HARVARD UNIVERSITY
Library of the
Museum of
Comparative Zoology
S^/^/^~S/an Oi^^o]
TRANSACTIONS
OF THE
SAN DIEGO SOCIETY OF NATURAL HISTORY
MUS. COMF. ZOOL. LiBWARY
AU6 1 9 1975
HARVARD
VOLUME 17 1972-1975
PRINTED FROM THE W. W. WHITNEY PUBLICATION ENDOWMENT
CONTENTS
1. Sound production and other behavior of Southern Right Whales, Eubalena glacalis. By William C. Cummings, James F. Fish, and Paul O. Thompson. 15 March 1972 1.14
2. Eastern Pacific Snake-Eels of the genus Callechelys (Apodes: Ophich- thidae). By John E. McCosker and Richard H, Rosenblatt. 25 April
1972 15-24
3. Paleontology and paleoecology of the San Diego Formation in northwestern
Baja California. By Robert W. Rowland. 9 June 1972 25-32
4. Seismic risk in San Diego. By Robert B. McEuen and Charles J. Pinckney.
19 July 1972 33-62
5. The feeding techniques of Stilt Sandpipers and Dowitchers. By P. J. K. Burton. 16 August 1972 63-68
6. Thoracic Cirripedia from Guyots of the Mid-Pacific Mountains. By M. V. Lakshmana Rao and William A. Newman. 31 August 1972 69-94
7. A new Mitrid from the western Atlantic. By George E. Radwin and Loyal
J. Bibbey. 31 August 1972 95-100
8. Diagnoses of new Cyprinid fishes of isolated waters in the Great Basin of western North America. By Carl L. Hubbs and Robert Rush Miller. 29 September 1972 101-106
9. Patterns of larval development in Stenoglossan Gastropods. By George E.
Radwin and J. Lockwood Chamberlain. 12 March 1973 107-118
10. A marine invertebrate faunule from the Lindavista Formation, San Diego, California. By George L. Kennedy. 28 March 1973 1 19-128
11. Post-Batholithic geology of the Jacumba area, southeastern San Diego County, California. By John A. Minch and Patrick L. Abbott, 10 April
1973 129-136
12. Revision of the coral-inhabiting barnacles (Cirripedia: Balanidae). By
Arnold Ross and William A. Newman. 20 April 1973 137-174
13. Biology, geographical distribution, and status of Atteva exquisita (Lepidoptera: Yponomeutidae). By Jerry A. Powell, John Adams Comstock
and Charles F. Harbison. 14 May 1973 175-186
14. Life history of the Western North American Goby, Coryphopterus nicholsii (Bean). By James W. Wiley. 30 October 1973 187-208
15. A new Platvdoris (Gastropoda: Nudibranchia) from the Galapagos Islands. By David K. Mulliner and Gale G. Sphon. 12 April 1974 209-216
16. The distribution and ecology of marine birds over the continental shelf of Argentina in winter. By Joseph R. Jehl, Jr. 28 June 1974 217-234
17. Mexican species of the genus Heterandria. subgenus Pseudoxiphophorus
(Pisces: Poeciliidae). By Robert Rush Miller. 28 June 1974 235-250
18. Lithostratigraphic variations in the Poway Group near San Diego, California. By Gary L. Peterson and Michael P. Kennedy. 6 December
1974 251-258
19. The autecology of Xantusia henshawi henshawi (Sauria: Xantusiidae). By
Julian C. Lee. 22 April 1975 259-278
20. A catalogue of Muricacean generic taxa. By George E. Radwin and Anthony D'Attilio. 16 May 1975 279-292
21. Bloods circulation in four species of barnacles (Lepas. Conchoderma: Lepadidae). By Bryan R. Burnett. 20 June 1975 293-304
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HARVARD UNIVERSITY
SOUND PRODUCTION AND OTHER BEHAVIOR
OF SOUTHERN RIGHT WHALES, EUBALENA GLACIAUS
WILLIAM C. CUM MINGS, JAMES F. FISH, AND PAUL O. THOMPSON
TRANSACTIONS
OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
VOL. 17, NO. 1 15 MARCH 1972
SOUND PRODUCTION AND OTHER BEHAVIOR
OF SOUTHERN RIGHT WHALES, EUBALENA GLACIALIS
WILLIAM C. CUMMINGS, JAMES F. FISH, AND PAUL O. THOMPSON
ABSTRACT.— In late June and early July, 1971, we recorded underwater sounds from southern right whales in Golfo San Jose, Argentina. The most common sound, a belch-like utterance, averaged 1.4 sec in duration, with most of its energy appearing below 500 Hz. Levels of this strong signal ranged from 172 to 187 dB, re 1 /^.N/nv at 1 m. The whales also produced two kinds of low-frequency moans. Simple moans had a narrow band of frequencies (centered at about 160 Hz) without appreciable frequency shifts. Com- plex moans exhibited a wider band width (centered at about 235 Hz), extensive frequency shifts, and over- tones. Other sounds were categorized as pulses, 0.06-sec bursts extending from 30 to 21(X) Hz, and mis- cellaneous sounds, comprising numerous phonations below 1950 Hz that varied in length from 0.3 to 1.3 sec. There was no periodic occurrence of sound production other than that related to the appearance of whales in the recording area at low tide.
When presented underwater playbacks of killer whale sounds, a right whale exhibited a behavior pat- tern called "spyhopping," but there was no obvious avoidance. An attack by five killer whales on two other right whales ended after 25 min, apparently without serious harm to the right whales. A common behavior of these southern right whales, "headstanding," may be associated with bottom feeding. Patterns of breath- ing varied considerably depending upon associated activities.
Local citizens reported that right whales appear in Golfo San Jos6 and nearby Golfo Nuevo each year in late June. They are most numerous in late August and September, and they disappear in November. We saw several consorting pairs that appeared to be courting, but no copulations and no very young whales.
This report describes the underwater sounds and behavior of southern right whales in Golfo San Jose, Argentina, in June-July, 1971. A brief summary of some of this work was presented earlier (Cummings et al., 1971).
The right whale is virtually world-wide in distribution (Hershkovitz, 1966). Although three subspecies have been recognized (australis: Southern Hemisphere; glacialis: North Atlantic; sind japonica: North Pacific), their validity is questionable (Rice and Scheffer, 1968). In this report we call this cetacean the "southern right whale" with no attempt to evaluate any subspecific rank.
Right whales, so named by whalers because these animals have a high oil content and float when dead, attain a maximum length of 18 m. They may be identified at sea by a characteristic V-shaped blow (Fig. lA), light-colored horny protuberances on the upper snout which include the bonnet (see Ridewood, 1901, and Matthews, 1938, for detailed descriptions), and by the lack of both a dorsal fin and throat grooves. Compared with other species of great whales, right whales are very rotund (Figs. IB, 2). Although killing of these animals has been prohibited for many years, the population remains exceedingly small in many regions (Ohsumi et al., 1971; Doi et al., 1971), and the species may be in danger of extinction through overharvesting.
Southern right whales have long been known to breed in bays and other sheltered waters (Scammon, 1874), and recent information indicates the same is true of northern animals (pers. comm. W. E. Schevill, Woods Hole Oceanogr. Inst.). In mid-July, 1969. Gil- more (1969) located 20 to 25 right whales that were courting and presumably mating in Golfo Nuevo, Argentina. On his advice, our attempts to record the vocalizations of this rare cetacean and to observe its behavior were concentrated in this region.
Little is known about vocalizations of the right whale. In discussing this whale's be- havior after being harpooned, Scammon (1874) wrote that, "after going a short distance, it frequently stops, or 'brings to,' 'sweeping' as it is said, 'from eye to eye,' and at the same time making a terrific noise called 'bellowing,' this sound is compared to that of a mam- moth bull, and adds much to the excitement of the chase and capture." Schevill and Wat- kins (1962) presented a description and a recording of low-frequency moaning sounds of northern right whales. Cummings and Phihppi (1970) reported low-frequency (20-174 Hz)
SAN DIEGO see. NAT. HIST., TRANS. 17(1): 1-14. 15 MARCH 1972
pulses and moans tentatively identified as being from northern right whales. These sounds, recorded off Newfoundland in December, 1965, appeared in repetitive, 11-min to 14-min stanzas that were separated by 8 to 10 min. Each stanza was composed of numer- ous signals appearing in a precise sequence that was repeated in the next stanza. Payne and McVay (1971) described a similar repetitive phenomenon, "songs," from the hump- back whale, Megaptera novaeangliae.
MATERIAL AND METHODS
This research was largely carried out from the National Science Foundation's re- search ship, HERO, a 38-m vessel that is managed by the United States Antarctic Re- search Program. We left Punta Arenas, Chile, on 11 June and proceeded north along the coast as far as Bahi'a Blanca, Argentina (39°N), returning to Punta Arenas on 16 July. Al- though other marine mammals were sighted along the coast, we did not see right whales in areas other than Golfo San Jose, an enclosed bay, 44 X 20 km, on the north side of the Valdes Peninsula (Fig. 3). There, from 21-24 June and from 1-8 July, we observed about 10 southern right whales, this estimate based on searching the entire Gulf on each of sev- eral days.
The deepest area of the Gulf is about 82 m, but most of the whales were observed near shore in less than 37 m. Because the Gulf is protected and shallow, we generally ex- perienced moderate or calm seas of State 2 or less. Air temperatures ranged from 6.1 to 8.3°C. We took bathythermographs in several areas of the Gulf and found isothermal conditions averaging 9.4° C. The ship's small boats occasionally were used for short excur- sions close to the whales, although we generally kept our distance so as not to in- tentionally crowd or molest them.
Underwater recordings were made with much the same system described by Calde- ron and Wenz (1967). Essentially, our recording system consisted of an acceleration-bal- anced hydrophone, flexible spar buoy, floating cable, calibrating device, sound-level me- ter, magnetic tape recorder, and monitoring equipment. Instruments used in playing sounds to right whales included a tape recorder (Uher 4200), preamplifier (Bogen BT- 35A), high-power amplifier (Optimation PA 250 AC), and an underwater sound projector specially designed by Wesley L. Angeloff of the Naval Undersea Research and Devel- opment Center. The frequency response of the playback system was ± 5dB from 650 to 3100 Hz, limited by the projector. Response of the receiving system was ±5 dB from 25 to 15000 Hz.
To obtain good recordings of low-frequency mysticete sounds, we have found it best to use a hydrophone that is relatively stationary in the water column and has a good low- frequency response, but not all the way down to 0 Hz. The response must be "roUed-off' in the low frequencies for use under normal sea conditions in order to prevent the recep- tion of low frequency noise. Such a hydrophone is still unsuitable, however, for towing from a moving vessel.
A hydrophone is designed to respond to changing pressure. Pressure changes caused by towing a hydrophone, or those resulting from the vertical excursions so characteristic of moderate or greater sea states, will usually produce excessive low-frequency noise. Coupled with the high sound pressure of low- frequency ambient noise (Wenz, 1962), ac- celeration and flow noise of this type will easily mask a low-frequency mysticete signal. Experience has taught us that such recordings have very low signal-to-noise ratio. More often, they are rendered useless by intermittent or even continuous blocking of the hydro- phone's preamplifier. The dynamic range of response of this preamplifier generally will not accommodate that of the electrical energy from sound pressures imposed on a hydro- phone under the above circumstances. The blocking occurs when the preamplifier is over- driven by an input signal that greatly exceeds the maximum input level designed for the amplifier.
To reduce these vertical and horizontal movements, we use an inflatable buoy for flexibility and a 450-m buoyant cable that is let out as fast as the ship drifts. The cable floats by means of a buoyant sheath that is molded around the conductors. In com- bination with a good-quality hydrophone having low-frequency rolloff and acceleration
Figure 1. A, V-shaped blow (exhalation) of a southern right whale; B, quartering view.
balancing, this system works well for us most of the time. Other investigators have dealt with the problem in other effective ways (Watkins, 1966).
The right whale sounds were recorded under quiet conditions, with all engines shut off. However, the ship's generator was needed during playback experiments. Most of our recordings were made while the ship was quietly lying to, 0.2 to 1.5 km from the whales. Whenever possible, we kept an account of the whales' behavior during the recordings,
both in a written log and as verbal comments on magnetic tape. Recording times of con- tacts varied from 10 to 120 min, after which the whales either moved out of an area or we simply stopped the recording.
PRONATIONS AND SOUND PLAYBACK
Southern right whales made several different types of powerful, low-frequency sounds resembling belches, moans, and pulses (Fig. 4, A-D). They also produced a num- ber of miscellaneous low-frequency sounds, too numerous to classify.
By far, the most common sound was a belch-like utterance that varied from 0.9 to 2.2 sec in duration and averaged 1.4 sec with principal energy centered at 235 Hz. Although the frequency ranged from 30 Hz to about 2200 Hz, the major portion fell below 500 Hz. Belch-like sounds often ended in about a 150-Hz upward frequency shift (Fig. 4A).
The first portion of the belch-like sound revealed two to four strong overtones with intervals of about 100 Hz. Sound pressure levels of the belch-like sounds were 172 to 187 dB, re 1 yuN/m^ ( = 72 to 87 dB, re 1 /^bar) at 1 m from the source. Source levels were de- termined from measurements in a band from 25 to 2500 Hz, thus including all fre- quencies oi belch-like sounds. These levels were derived from the absolute received sound pressure levels at the hydrophone (as measured in the laboratory from the calibrated recordings) and the estimated distances of the whales from the hydrophone. The calcu- lations took into account an estimated spreading loss of 6 dB per distance doubled. Atten- uation losses were regarded as negligible, because the whales were so close and their calls so low in frequency.
Southern right whales also made moaning sounds of several different kinds. Their moans were classified into two basic types, simple and complex (Fig. 4B). Simple moans had sound energy that was confined to a relatively narrow band without appreciable shifts in frequency. Simple moans lasted from 0.6 to 1.6 sec. The highest frequency noted was 320 Hz, the lowest was 70 Hz, and the region of principal energy was about 160 Hz. Complex moans exhibited a wider band of energy, extensive frequency shifts, overtones, and a longer duration compared to simple moans. The highest frequency observed among complex moans was 1250 Hz, the lowest was 30 Hz, and the region of principal energy was 235 Hz. The duration of complex moans ranged from 0.2 to 4.1 sec.
The third most common of the major types of right whale sounds were pulses (Fig. 4C). These sounds extended from 20 to 2100 Hz, and lasted only about 0.06 sec. The pul- ses frequently occurred in conjunction with a moan.
The remaining sounds consisted of numerous, miscellaneous, low-frequency sounds that varied in length from 0.3 to 1.3 sec (Fig. 4D). All of these were below 1950 Hz.
We were unable to associate sound production with any specific behavior. The sounds emanated from surfacing as well as from diving whales. They came from single whales or from small groups of two to three individuals. Although some of the right whales may have been feeding and others presumably were courting and perhaps mating, we were unable to associate any sounds with a particular activity. In one instance we were in a small rubber boat, close to a surfacing whale, when the whale produced a thun- derous, cavernous, bellow between two exhalations. The sound was clearly audible in air and may have been the same type of sound described by Scamrnon (1874). This whale was one of two that were consorting near us, in very shallow water.
Extensive recordings were made in the southeast corner of Golfo San Jose to deter- mine if there was any diurnal periodicity in sound production. These recordings were made for 15 min every 2 hrs, beginning at 1830 on 2 July and ending at 1030 on 4 July. We continued to listen for 10 to 20 min after each recording. Most of the right whale sounds on these recordings occurred close to the three low tides (Table 1), a phenomenon that may have been associated with the appearance of right whales in this area and not necessarily with any daily rhythm in sound production. At other times the whales moved along shore, either toward the west or north. There was no indication of a difference in daytime vs nighttime activity in sound production. In this general vicinity we doubt that whale sounds originating more than about 2 km away would have been detected, because
of the limited propagation which could be expected in the presence of the coves, shallow water, and disrupted bottom.
Table 1. Occurrence of right whale sounds on nineteen 15-min recordings.
|
Time of Day |
Date |
|
1830 |
2 July |
|
2030 |
2 July |
|
2230 |
2 July |
|
0030 |
3 July |
|
0230 |
3 July |
|
0430 |
3 July |
|
0630 |
3 July |
|
0830 |
3 July |
|
1040 |
3 July |
|
1245 |
3 July |
|
1515 |
3 July |
|
1945 |
3 July |
|
2150 |
3 July |
|
2345 |
3 July |
|
0145 |
4 July |
|
0345 |
4 July |
|
0545 |
4 July |
|
0830 |
4 July |
|
1030 |
4 July |
No. of Sounds
Time of Low Tide
0 0 4 3
30 0 3 1 0
28 1 4 0
10
11 1 6 0
6'
0112
1348
0200
'Five of these 6 sounds occurred in 9 sec and appeared to be a series of sounds from a single right whale.
Our earlier experiments had shown that certain marine mammals appeared to recog- nize underwater sounds of killer whales. Migrating gray whales, Eschrichtius robustus, off southern California, avoided underwater playbacks of killer whale "screams," (Cum- mings and Thompson, 1971); and playbacks prevented white whales, Delphinapterus leucas, from swimming up the Kvichak River in Alaska, where young salmon were migra- ting to the open sea (Fish and Vania, 1971). Thus, playback experiments provide a new source of information about the behavior of whales in their natural environment. For ex- ample, the escape reaction of the gray whale to killer whale sounds can be used to test the hearing capabilities of this species. Also, by playing tapes of certain segments of killer whale signals it may be possible to determine which parts of these signals induce an avoid- ance reaction.
We played back killer whale "screams" to a group of three southern right whales. HERO was 1.8 km from the beach, in 12 m of water, and all of the whales at first were less than 2 km away. The underwater sound was monitored with a hydrophone. We ob- served the whales for 15 min before playback. The first transmission consisted of 5 min of random noise, as a control. After 2 min of silence we transmitted a 5-min tone (described by Cummings and Thompson, 1971), also as a control. After 3 min of silence we played back 5 min of prerecorded killer whale sounds. Sound pressure levels of the playbacks, measured in situ with a calibrated system, varied from 159 to 163 dB, re 1 /tN/m- at 1 m from the source. Generator noise from the ship measured 134 dB, over the effective band- width of the recording system, at the same location and time of the playback experiments.
Only one whale could be seen well enough to observe its reaction. For 15 min before, it had been moving slowly back and forth along the beach, blowing at irregular intervals. There was no obvious change in its behavior when confronted with either the random noise or the tone. When the killer whale "screams" were played back, the right whale ap- peared to behave as before, except that it frequently raised its head out of the water in a "spyhopping" posture. This behavior consisted of raising the head vertically out of the water with the eyes above the surface. In earlier experiments, Cummings and Thompson (1971) found that gray whales fled a sound source for an appreciable distance and then "spyhopped." They concluded, as did Gilmore (1958), that "spyhopping" was an in- vestigative behavior.
Figure 2. Dorsal view of a southern right whale heading away from the ship. Note the widely separated blow holes and the rotund form of this species.
OTHER BEHAVIOR
On 4 July, in order to make detailed photographs, we accompanied a pair of right whales that apparently had been courting. We had just finished our work at dusk, and they had resumed their rolling antics near the surface, when a group of killer whales ap- peared off hero's stern. The killer whales were heading away from the right whales; then, suddenly, they whirled around and swam straight towards the two right whales which were separated by about 45 m.
When the killer whales were about 70 m away, the right whales came together so closely that they appeared to be touching one another. As soon as the killer whales had reached them, the right whales started slashing the water's surface with their flukes and flippers. The right whales were then blowing every 10 to 20 sec, twisting and turning in
|
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|
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1 |
||
|
. |
VALDES |
PENINSULA j |
|
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^^ Pta^ |
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7 |
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^.^Pla Delgada |
|
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^^^^-•i»la |
10 n. |
m iles |
|
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Figure 3. Chart showing the Valdes Peninsula of Argentina.
the water as the killer whales swam around them.
We were too far away to see whether or not the killer whales were actually biting the right whales. However, in other respects it appeared to be a full-fledged attack. On at least three occasions, one or the other right whale was on its back, thrashing the water's surface with its flippers and flukes at the same time. At one point, the right whales were completely encircled by the killer whales. The most impressive of the large whales' defen- sive maneuvers was the way they kept together— rolling, turning, and slashing within such close quarters. In at least two instances, the attacked and the attackers all were below the surface with nothing showing but a slick of whirhng water.
We moved to within 0.5 km to record any underwater sounds at short range. How- ever, when the ship had stopped, and we had only been recording for a short time, the killer whales left their prey and swam toward the ship. We counted five killer whales, in- cluding one very young animal and apparently four females. The attack had lasted 25 min, and occurred in 30 m of water.
The right whales then moved into very shallow water (7-11 m) where they rolled at the surface, more slowly than before the attack, exhibiting a notable decrease in activity. There were no signs of blood or other evidence of physical harm in the vicinity of the at- tack.
We recorded for about 3 min before the attack ended and for 15 min afterward, but obtained no underwater sounds from either species, even though both were well within range of the hydrophone. Gray whales and white whales became significantly quieter when confronted with killer whale sounds (Cummings and Thompson, 1971; Fish and Vania, 1971). Nevertheless, even in a recording as short as ours, we expected some phona- tions from the loquacious killer whales or the right whales. However, under these circum-
1.5-
1.0-
TIME, sec
Figure 4. Sonagrams of sounds from southern right whales recorded in Golfo San Jose, Argentina. Row A, two belch-like sounds; Row B, one simple and two complex moans; Row C, pulses associated with simple moans; Row D, two examples of miscellaneous sounds. The effective bandwidth of the analyzing filter for these sona- grams was 10 Hz.
2 -
z
z o
z
UJ
>
z
CO
0 6
5 -
Jl
Figure 5. Histogram showing the time du- ration between consecutive ventilations of the southern right whale. Conditions A, B. and C explained in text.
3 -
2 -
111
CONSECUTIVE VENTILATIONS
Stances neither may have profited from being noisy (see Schevill, 1964).
We saw killer whales on two other occasions in Golfo San Jose— a group of three on 1 July, in the mid Gulf, and another group, of six, on 8 July, near the east end. Evidently, these animals are common near Valdes Peninsula as several observers reported seeing them inside and outside of the two gulfs.
Two mussel fishermen, Jorge Enrique Ramirez and Jorge Raul Terenzi, related to us that their Captains, Roque Godio and Calixto Gerez, had also witnessed attacks of killer whales on right whales near the Valdes Peninsula. In one such attack they related that five killer whales "hammered" away at the head region until the right whale opened its mouth. The killer whales then started tearing away at the tongue. The area was colored with blood, the killer whales left, and the right whale was lying motionless at the surface, apparently dead.
Apparent pairs of right whales were seen on several occasions. They spent much time rolling at the water's surface, exposing bellies, backs, flukes and flippers, and occasionally "spyhopping." Members of a pair were often very close to each other, and at times they appeared to be in physical contact. Some of this behavior may have been associated with courtship, but we obtained no evidence of actual mating. Since we could not recognize in- dividual whales, we could not determine if the association was prolonged for more than about half a day.
The "headstanding" posture consisted of holding the flukes upright and out of the water for periods up to 2 min. During this time, the flukes slowly rocked back and forth or from side to side, occasionally arching downward toward the water's surface. "Head- stands" only occurred in very shallow depths, and the behavior was more frequent among single whales.
Right whales appeared to have little fear of the ship or the rubber boats. We once ventured as close as 9 m with a rubber boat, and neither one of a consorting pair showed any apprehension. Other observers have had the same experience (Matthews, 1938). Moreover, the two fishermen who were interviewed reported that they once were awak- ened at night by a right whale rubbing its head on the side of their boat.
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Occasionally, kelp gulls, Larus dominicamis, and brown-headed gulls, L. macuU- pennis, landed and rode on whales at the surface. One gull that landed near the blowhole was blown off by the next expiration. The gulls actually pecked at the whales, and possi- bly were feeding on parasites.
The whales we studied were rather sluggish. Many swam very slowly at the surface for long distances— in one case about 4 km without diving. Apparently, the whales were incapable of speeds greater than about 14.8 km/hr (8 knots). HERO's top speed of 18.5 km/hr (10 knots) easily enabled us to overtake two whales, whereas at 14.8 km/hr the ship could only keep up with them. The two that we accompanied tired more quickly than
II
other mysticete whales we have studied.
The whales' respiratory rate depended upon their activity. Whales swimming slowly at the surface ventilated about once a minute, or once every 2 to 3 min when performing "headstands" in the interim (Fig. 5A). A whale encountered in deeper water as it swam fairly rapidly and directly towards shore breathed irregularly, diving for periods that var- ied between 0.5 and 4.3 min (Fig. 5B). A whale we had been following stayed down for 6.2 min (Fig. 5C), and at another time its longest dive was 8 min.
Transiting right whales (those that moved along on a direct course without spending much time at the surface) usually displayed their flukes just before an extensive dive (Fig. 6). However, the next to last surfacing was sometimes accompanied by "false fluking," the flukes being drawn up close to but not above the surface.
Our brief stay in Golfo San Jose did not permit long-term observations of southern right whales, but the following information was obtained from local observers, particu- larly Santiago Ortega, Perez Macchi, and Carlos Oscar Garci'a:
1. Southern right whales occur in Golfo San Jose and nearby Golfo Nuevo each year. The whales come from the south and begin to show up at Golfo San Jose in late June, before they appear in Golfo Nuevo. They are most numerous in late August and September. Fewer are present in October, and all disappear during November.
2. The total number of right whales in the Valdes region is unknown, mainly because there is replacement, with some arriving and some departing throughout the season. Up to 30 may be seen at one time in Golfo San Jose during the peak of the season, and others can be found out to sea, just east of the peninsula. The reporters knew of no other place along the Argentine coast where this species enters bays each year.
3. All observers thought that right whales court and copulate in the two gulfs, but none thought that the young were born there. Small whales, seen in these gulfs, were judged too large to have been born there during a current "whale season."
4. Right whales reportedly have become more numerous in this area in recent years, as is true of elephant seals and sea lions of the region, possibly because the Valdes Penin- sula has become a wildlife refuge for land and sea animals. It is illegal to kill marine mammals in either gulf and the area is heavily patrolled.
DISCUSSION
We have recorded underwater sounds from six of the ten species of mysticete whales, and all the sounds have been low-frequency utterances below 3000 Hz. Although there are a few reports of high-frequency phonations in the presence of mysticetes (Perkins, 1966; Poulter, 1968; Beamish and Mitchell, 1971), baleen and toothed whales are markedly diff"erent in that low frequency is more typical of the former and high frequency of the latter. A good single hydrophone can yield an acceptable recording of these strong low-frequency signals, when used in calm seas and not towed through the water .
(The single, omnidirectional hydrophone may eventually be replaced by an eff"ective line array of several transducers that could be towed from a drifting or sailing ship. In theory, the advantage of a line array comes from increased signal-to-noise ratio accom- plished through directivity toward the sound source. The means for attaining such direc- tivity generally involves proper spacing of the individual hydrophones to phase out the input from directions other than those that are normal to the array's conformation. The extent of spacing is related to the wavelength involved and thus would be considerable m the case of low-frequency mysticete sounds where wavelengths are as long as 120 m or more. A 5-hydrophone array for this frequency would approximate 300 m in length. Un- fortunately, present systems such as this are burdensome to use, and they involve complex signal processing. Moreover, the line array is not within the budget of most scientific in- vestigations, nor is one yet available that is relatively noise-free with a high enough response across the entire frequency range of mysticete sounds.)
The belch-like sounds and complex moans of southern right whales reported here re- semble some of the sounds of northern right whales presented by Schevill and Watkms (1962). However, we also found dissimilarities. Diff"erences in behavior, m addition to pos-
12
sible regional differences resulting from evolutionary divergence, could account for such a disparity. Furthermore, our recordings had no evidence of repetitive stanzas that Cum- mings and Philippi (1970) suggested were from northern right whales. Their recordings were made in the open, deep sea, far from land in an area of the North Atlantic where breeding of northern right whales is unknown. The present recordings were made near shore in a protected, shallow embayment, where whales were courting.
Our earlier sound playback experiments were so successful in producing avoidances by gray whales and white whales that we expected the right whales to behave similarly, especially as they occur in an area where killer whales are known to attack them. Perhaps other playback attempts would produce a more decisive reaction. The source level of the sounds played was less than that used in experiments with gray whales and white whales. Also, the right whales were an appreciable distance from the ship, in very shallow water where we would not expect good propagation. Possibly the playback was not very audible to the whales in this location.
Right whales exhibited the "headstanding" posture mostly in the southeast comer of Golfo San Jose, in an area reported by fishermen to have dense populations of mussels. Local fishermen believe that this behavior is associated with feeding on mussels, and we support this idea. We observed the whales in water that was shallow enough to allow their heads to touch bottom and their tails to be exposed. In two instances of "headstanding," at a location where the water was only 6 to 8 m deep, the whales either had to be in con- tact with the bottom or had to arch their whole bodies. It is doubtful that they could have held their tails out of the water for such a long time, with the remainder of the body bent away from the bottom. Moreover, we did not observe "headstanding" in places known to be deeper than the estimated length of the whales. Right whales are positively buoyant, but holding their tails above the surface may make them just heavy enough in water to keep their heads against the bottom.
The idea of mysticetes feeding on mussels is not without precedent. Scammon (1874) reported that gray whales fed on mussels, based upon his having observed the mussels in the whales' "maws." In fact, he included the term "Mussel-digger" in his list of vernacular names for the gray whale.
The Valdes Peninsula area is well suited for studies of marine mammals. In addition to southern right whales and killer whales in Golfo San Jose, we observed southern sea lions (Otaria flavescens), elephant seals (Mirounga leonina), bottlenose porpoises {Tur- siops truncatus), "white-sided" porpoises {Lagenorhynchus sp.), and common porpoises {Delphinus sp.). To the south, large numbers of sea lions haul out at points Leon, Loma, Piramida, and Delgada (Fig. 3). There were about 800 sea lions at Punta Piramida at the time of our visit, and we were told this number would increase to 3000 in December. Nat- ural parks with facilities for visitors have been established at Punta Loma and Punta Pira- mida. Some elephant seals occurred with the sea Uons at Punta Leon. From our inter- views, we learned that elephant seals are most numerous from September to December, especially at Punta Norte. It was in this area, in 1969, that Dr. Raymond M. Gilmore saw 150-200 elephant seals as early as 13 July (pers. comm.). The seals were in three scattered groups, some of them occurring with sea lions.
ACKNOWLEDGMENTS
This work was supported by the National Science Foundation, U.S. Antarctic Research Program, Grant AG-261; the Naval Undersea Research and Development Center, Independent Research Projects; and by the Office of Naval Research, Oceanic Biology Program. Dr. George A. Llano (NSF) was very helpful in making ar- rangements for the cruise. We are grateful to Captain Franklin P. Liberty and the entire crew of HERO for their splendid support and seamanship. We thank Dr. Joseph R. Jehl, Jr., for his help in spotting marine mammals and identifying the birds for us; CDR Alfredo A. Yung, geophysicist with the Argentine Navy, and Angel Fer- rante, marine technician at the Argentine Institute of Oceanography, for their valuable advice and assistance on board; Carlos Bassi, Perez Macchi, Santiago Ortega, Carlos O. Garci'a, Jorge E. Ramirez, Jorge R. Terenzi, and others, for their very useful information; Charlotte L. Meinert and Alan R. Hamel, for assistance in preparing the manuscript; and William E. Schevill, William A. Watkins, and R. S. Gales, for their helpful comments.
13
REFERENCES CITED
Beamish, P., and E. Mitchell
1971. Ultrasonic sounds recorded in the presence of a blue whale, Balaenoptera musculus Deep-sea Res
18: 803-809.
Calderon, M. A., and G. M. Wenz
1967. A portable general-purpose underwater sound measuring system. Naval Undersea Warfare Ctr., Tech. Paper 25. 46 p.
Cummings, W. C, J. F. Fish, P. O. Thompson, and J. R. Jehl, Jr.
Bioacoustics of marine mammals off Argentina, R/V HERO, Cruise 71-3. Antarctic Jour U S VI(6)- 266-268.
Cummings, W. C, and L. A. Philippi
1970. Whale phonations in repetitive stanzas. Naval Undersea Res. Develop. Center, Tech. Publ. 196. 8 p. Cummings, W. C, and P. O. Thompson
1971. Gray whales, Eschrichtius robustus, avoid the underwater sounds of killer whales, Orcinus orca. Fish. Bull. 69(3): 525-530.
Doi, T., S. Ohsumi, and Y. Shimadzu
1971. Status of stocks of baleen whales in the Antarctic, 1970/71. Internatl. Comm. Whahng, 21st Rept.- 90-99.
Fish, J. F., and J. S. Vania
1971. Killer whale, Orcinus orca, sounds repel white whales, Delphinapterus leucas. Fish. Bull. 69 (3): 531- 535.
Gilmore, R. M.
1969. Populations, distribution, and behavior of whales in the western South Atlantic: Cruise 69-3 of R/V HERO. Antarctic Jour. U.S., IV (6): 307-308.
Hershkovitz, P.
1966. Catalog of living whales. U.S. Natl. Mus. Bull. 246.
Matthews, L. H.
1938. Notes on the southern right whale, Eubalaena australis. Discovery Rept. XVll: 169-182.
Ohsumi, S., Y. Shimadzu, and T. Doi
1971. The seventh memorandum on the results of Japanese stock assessment of whales in the North Paci- fic. Internatl. Comm. Whaling, 21st Rept.: 76-89.
Payne, R. S., and S. McVay
1971. Songs of humpback whales. Science 173 (3997): 585-597.
Perkins, P. J.
1966. Communication sounds of finback whales. Norsk Hvalfangst-Tidende (Norwegian Whaling Gazette) 55: 199-200.
Poulter, T. C.
1968. Marine mammals, p. 405-465. /« T. A. Sebeok [ed.]. Animal communication, techniques of study and results of research. Indiana Univ. Press, Bloomington, Ind.
Rice, D. W., and V. B. SchefTer
1968. A list of the marine mammals of the world. U.S. Fish WildHfe Ser., Spec. Sci. Rept.-Fish. No. 579.
Ridewood, W. G.
1901. On the structure of the horny excrescence, known as the bonnett, of the southern right whale {Ba- laena australis). Proc. Zool. Soc. Lond. 1901: AA-Al.
Scammon, C. M.
1874. The marine mammals of the north-western coast of North America, and the American whale fishery. Facsimile edition, Manessier Publishing Co., Riverside, Calif. 319 p.
Schevill, W. E.
1964. Underwater sounds of cetaceans, p. 307-316. In W. N. Tavloga [ed.]. Marine bio-acoustics, proceed- ings of a symposium held at the Lerner Marine Laboratory, Bimini, Bahamas, April 11 to 13, 1963. Pergamon Press, N.Y.
Schevill, W. E., and W. A. Watkins
1962. Whale and porpoise voices. Woods Hole Oceanogr. Inst, (with a phonographic record) 24 p.
Watkins, W. A.
1966. Listening to cetaceans, p. 471-476. In K. S. Norris [ed.]. Whales, Dolphins, and Porpoises. Univ. Cali- fornia Press, Berkeley and Los Angeles.
Wenz, G. M.
1962. Acoustic ambient noise in the ocean: spectra and sources. J. Acoust. Soc. Amer. 34 (12): 1936-1956.
Naval Undersea Research and Development Center, Applied Bioacoustics Branch, San Diego, California 92132
MUS. COMI>. ZOOU
LIBRARY
DEC 71976
EASTERN PACIFIC SNAKE-EELS u^tvERSr^f
OF THE GENUS CALLECHELYS (APODES: OPHICHTHIDAE)
JOHN E. McCOSKER AND RICHARD H. ROSENBLATT
TRANSACTIONS
OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
VOL. 17, NO. 2 25 APRIL 1972
EASTERN PACIFIC SNAKE-EELS OF THE GENUS CALLECHELYS (APODES: OPHICHTHIDAE)
JOHN E. McCOSKER AND RICHARD H. ROSENBLATT
ABSTRACT.-Three species of Callechelys are recognized from the eastern tropical Pacific. Two, C. eris- tigmus and C. galapagensis. are described as new. Callechelys cliffi Bohlke and Briggs is redescribed from adults. The species differ in coloration, body proportions and vertebral number. Callechelys cliffi and C. eristigmus n. sp. range from Panama to the Gulf of California, and C. galapagensis is known only from the Galapagos Islands. Vertebral number and proportional tail length of the 15 species of Callechelys are given. Lineages within the genus are indicated by the presence or absence of a scapula and the condition of the urohyal.
Callechelys is one of the larger genera of the Ophichthidae with fifteen species, mainly Hmited to the tropics. The species are distinguished on the basis of coloration, ver- tebral number, and certain body proportions, mainly body depth and preanal distance. Like most snake-eels, members of the genus are sand dwelling and restricted to continen- tal shelf depths. Some of the species attain lengths of one meter. It is not known whether they occupy burrows or wander extensively through the sand. Despite the sand-dwelling habit, many of the species are boldly marked. It is possible that they leave the sand at night, and the color pattern may have significance at these times. Occasional specimens have indeed been taken at the surface under lights at night.
When Storey (1939) published her revision of Callechelys, a single specimen, doubt- fully referred to C. marmoratus or C. luteus, was known from the eastern tropical Pacific. Subsequently (Bohlke and Briggs, 1954) another specimen was taken and made the holo- type of a new species. The collections at the Scripps Institution of Oceanography, the De- partment of Zoology, University of California, Los Angeles, and the University of Costa Rica now contain 55 eastern Pacific specimens of Callechelys. The recent collections of these eels are attributable to the development of synergized emulsified rotenone products. The use of these products has resulted in rich collections of ophichthid eels and other sand-dwelling fishes not obtainable with powdered derris root. Even with the use of pow- erful ichthyocides, the collection of these eels is not easy. Either because of a resistance to rotenone or the time involved in transport of rotenone down into the sand, they emerge long after most fishes are dead. Ophichthids may begin to appear after other fishes have been picked up and the station apparently completed.
Our material can be separated into three species, only one of which has been de- scribed. Callechelys cliffi Bohlke and Briggs, heretofore known only from the just-trans- formed holotype, can now be described on the basis of adult characters.
MATERIALS AND METHODS
Material used in this study is housed in the following institutions: University of Cali- fornia at Los Angeles, Department of Zoology (UCLA); National Museum of Natural History (USNM); California Academy of Sciences, material previously at Stanford Uni- versity, (SU); Universidad de Costa Rica, Museo de Zoologia (UCR); and Scripps In- stitution of Oceanography (SIO). Paratypes of Callechelys eristigmus will be deposited at the Academy of Natural Sciences of Philadelphia and the USNM.
All measurements are straight-line measurements, made either with a 300 mm ruler with 0.5 mm gradations (for standard length, trunk length, and tail length) and recorded to the nearest 0.5 mm, or with dial calipers (all other measurements) and recorded to the nearest 0. 1 mm. Head length is measured from the snout tip to the posterodorsal margin of the gill opening; trunk length is taken from the end of the head to mid-anus; body
SAN DIEGO see. NAT. HIST, TRANS. 17 (2): 15-24, 25 APRIL 1972
16
depth does not include the fin. Counts and proportions in Tables 2-4 include the mean, range, and 95% confidence limits of the mean. Fin ray and vertebral counts (which in- clude the hypural) were made using radiographs or cleared and stained specimens.
Callechelys Kaup, 1856
The genus Callechelvs may be distinguished from all other ophichthid genera on the basis of the following combination of characters: tip of tail a hard point; pectorals absent; anal fin present; dorsal fin originating on head; head and body laterally compressed; an- terior nostrils tubular; a median groove on underside of snout; gill openings low-lateral and converging forward, the isthmus much narrower than the gill opening length; inter- maxillary and vomerine teeth present, canine teeth absent.
Key to the Eastern Pacific Species of Callechelys
la. Tail considerably shorter than head and trunk, 3.25-3.75 in total length. Greatest body depth of adults 3.3-3.5 times in head length. Color pattern of strongly con- trasted round dark spots about as long as snout. Vertebrae 154-163 Callechelys ehstigmus n. sp.
lb. Tail almost equal to head and trunk, 2.2-2.4 in total length. Greatest body depth of adults 1.7-2.8 times in head length. Color pattern either solely of numerous small dark spots, or with larger dark oblongs as well, in which case the total vertebrae are 170-174 2
2a. Color pattern of numerous fine spots, not much larger than eye diameter, fins with a distinct white edge. Vertebrate 149-158 Callechelys clijfi Bohlke and Briggs
2b. Color pattern with oblong blotches varying in size between an eye diameter and a snout length along the major axis, fins without a white edging. Vertebrae 170-174 Callechelys galapagensis n. sp.
B
Figure la. Callechelys eristigmus n. sp., holotype, SIO 65-263, 503.5 mm total length, b. Head region of holotype of Callechelys eristigmus n. sp. Arrow indicates true dorsal fin origin.
Callechelys eristigmus n. sp.
Figs. 1, 2a, 5; Tables 1, 2, 5 Description of holotype. —Counts and proportions of the holotype are given in Table 1. Proportions of the holotype and 29 paratypes are given in Table 2.
Body laterally compressed throughout its length, tapering posteriorly to a hard fin-
17
Table 1. Counts, and proportions in thousandths, of the holotypes of the eastern Pacific species of Callechelys.
|
C. cliffi |
C. eristigmus |
C. galapagensis |
|
|
Total length (mm) |
93.5 |
503.5 |
818.0 |
|
Total vertebrae |
155 |
159 |
172 |
|
Preanal vertebrae |
105 |
92 |
|
|
(thousandths |
of total length) |
||
|
Head |
101 |
72 |
74 |
|
Trunk |
467 |
628 |
483 |
|
TaU |
433 |
300 |
444 |
|
(thousandths |
of head length) |
||
|
Dorsal fin origin |
606 |
318 |
312 |
|
Snout |
170 |
142 |
133 |
|
Upper jaw |
340 |
285 |
262 |
|
Eye |
74 |
41 |
46 |
|
Interorbital |
132 |
108 |
|
|
Isthmus |
74 |
55 |
119 |
|
Depth behind gill opening |
351 |
345 |
464 |
|
Width behind gill opening |
249 |
265 |
|
|
Depth at anus |
330 |
258 |
365 |
|
Width at anus |
195 |
249 |
|
|
Gill opening length |
145 |
202 |
less point. Depth behind gill openings 40 times and at anus 51 times in total length; width behind gill openings 55 and at anus 71 in total length. Head and trunk 1.4. head 13.8 in total length. Snout acute, rounded at tip. Lower jaw included, its tip slightly before eye and midway between anterior and posterior nostrils. Eye small, about as long as tube of anterior nostril. Posterior nostrils open into mouth although their distal edges are open to the outer edge of lip, visible externally as a slit. Surface of head, trunk and tail markedly wrinkled (except top and sides of anterior portion of head smooth), with approximately 30 longitudinal grooves on each side of body. Tongue adnate. Branchial basket expanded, supported by 31 pairs of branchiostegals and jugostegalia which broadly overlap along ventral midline. Urohyal simple, a single slender filament posteriorly. Tip of lower jaw and lateral skin folds of upper jaw covered with numerous papillae (Fig. 2a).
Teeth small and pointed (Fig. 2a), uniserial in jaws. An anterior intermaxillary tooth- pair covered by skin folds for most of their length, followed by seven vomerine teeth that become biserial posteriorly.
Preoperculomandibular, temporal, postorbital, suborbital, and supraorbital series of pores present (Fig. lb). Lateral line beginning on head with 10 pores before gill opening (lateral line canal and pores difficult to discern due to skin folds and waxy precipitate which forms on preserved specimens). Total right lateral line pores of the cleared and stained specimen 140, 92 before anus. Last pore ca. 0.15 head lengths before tail tip. Dor- sal fin origin on head, above and slightly behind rictus; median fins end about a snout length before tail tip. Fin rays in dorsal 498, anal 143 (counted from the cleared and stained paratype).
Gill arches and hyoid apparatus of two paratypes removed and stained. First basi- branchial ossified, second cartilaginous, third and fourth absent. Hypobranchials 1-2 os- sified, third cartilaginous. Ceratobranchials 1-4 ossified, fifth absent. Infrapharyngobran- chials 2-3 ossified. Lower pharyngeal teeth in elongate patches on fourth ceratobranchial and extend onto hypobranchial; upper pharyngeal tooth plate smaller, attached to distal ends of epibranchials 2-4 and second infrapharyngobranchial (I3 of Nelson, 1966).
Color in alcohol mostly cream, overlain with numerous dark spots that extend onto the dorsal fin membrane. Chin, throat, and venter often spotted, but always less so than dorsum. Spots on nape and snout smaller (nearly as large as eye).
Etymology.— From the Greek epi (eri), intensive participle, and a-TLyna (stigma), spot, in reference to the distinctive coloration; regarded as an adjective.
18
Remarks.— Gulf of California specimens are inseparable on the basis of coloration and morphology from those from southern localities (Cocos Island, Costa Rica, and Pan- ama). The mean vertebral number of specimens from these localities (158.3 for 29 Mexi- can specimens, 156.1 for 8 specimens from the south) are significantly different (P = .05 by t test); however, the degree of joint non-overlap is not sufficient to warrant taxonomic rec- ognition.
Table 2. Callechelys eristigmus n. sp., counts, and proportions in thousandths, of holotype and 29 para- types; mean, 95% confidence limits of the mean, and range.
|
X |
95% C. L. |
range |
||
|
Total length (mm |
) |
284-1 126mm |
||
|
Vertebrae (37 specimens) |
157.9 |
157.2-158.5 |
154-163 |
|
|
(thousandths of total length) |
||||
|
Head |
76 |
74-77 |
67-83 |
|
|
Trunk |
628 |
624-632 |
610-662 |
|
|
Tail |
295 |
291-299 (thousandths of head length) |
268-309 |
|
|
Dorsal fin origin |
327 |
316-337 |
250-379 |
|
|
Snout |
152 |
149-155 |
135-167 |
|
|
Upper jaw |
266 |
260-272 |
228-289 |
|
|
Eye |
46 |
44-48 |
34-56 |
|
|
Interorbital |
113 |
109-117 |
98-140 |
|
|
Left gill opening 1 |
ength |
142 |
136-147 |
111-168 |
|
Isthmus |
58 |
54-61 |
46-77 |
|
|
Depth behind gill |
opening |
295 |
286-304 |
254-345 |
|
Depth at anus |
250 |
237-262 |
172-338 |
|
|
Width behind giU |
opening |
194 |
185-203 |
144-272 |
|
Width at anus |
182 |
174-190 |
140-234 |
Material examined.— WoXoiy^Q: SIO 65-263, a 503.5 mm adult from Isla San Jose, Gulf of Cahfornia, Baja California Sur (24°52'15"N, 1 10°37'00"W). Taken with rotenone and SCUBA in depths of 20-25 m on a sand and boulder bottom by R. H. Rosen- blatt and party on 7 July 1965. Paratypes: all collected using rotenone ichthyocides in rel- atively shallow water (5-25 m), generally over a sand and rock bottom. Panama-Islas Secas, Isla Cavada, SIO 70-136, 2(359-465); Islas Secas, Isla Seca, 70-140, 2(342-450). Costa Rica-Isla del Coco, UCLA 58-378, 1(361); Isla del Caiio, UCR 423-126, 5(216-491). Gulf of California, Baja California Sur-Isla Carmen, UCLA 65-77, 3(325-420), SIO 65-299, 2(328-357); Isla Santa Catalina, SIO 65-337, 2(411-469); Isla Santa Cruz, SIO 65-342, 2(408-420), SIO 65-354, 2(431-498, the smaller specimen cleared and stained); Punta Nopolo, SIO 65-270, 1(564); Isla San Jose, SIO 65-263, 1(323, collected with the holotype), SIO 65-260, 1(372); Isla Espiritu Santo, SIO 61-277, 1(1 126); Bahia de los Lobos, SIO 61- 279, 1(418); Isla Ceralbo, SIO 61-256, 1(494), SIO 61-259, 2(399-493); Bahia de Palmas, UCLA 59-249, 1(285), UCLA 59-251, 2(284-538); Punta Pescadero, SIO 61-252, 2(317- 557); Punta Los Frailes, SIO 61-239, 1(425); El Tule Ranch, east of Cabo San Lucas, SIO 65-185,3(363-552).
Callechelys galapagensis, n. sp. Figs. 2b, 3, 5; Tables 1, 3, 5 Callechelys marmoratus, nee Bleeker, Fowler, 1932: 3. Fowler, 1938: 251. Callechelys luteus, nee Synder, Storey, 1939: 69.
Description of holotype.— Connie and proportions of the holotype are given in Table 1. Proportions of the holotype and 3 paratypes are given in Table 3.
Body laterally compressed throughout its length, tapering posteriorly to a hard fin- less point. Depth behind gill openings 29 times and at anus 37 in total length; width be- hind gill openings 51 and at anus 54.5 in total length. Head and trunk 1.8, head 13.5 in total length. Snout acute, rounded at tip. Lower jaw included, its tip closer to base of ante- rior nostrils than to a vertical from anterior margin of eye. Eye small, about equal in length to tube of anterior nostril. Posterior nostrils open into mouth, visible externally as a slit. Surface of head and trunk markedly wrinkled (except top and sides of anterior por-
19
Figure 2a. Dentition of holotype of Callechelvs eristigmus. b. Callechelys galapagensis. n. sp.. a paratype, UCLA 67-33. c. Callechelys cliffi. SIO 62-42.
tion of head smooth) as in C. eristigmus, but becoming smoother posteriorly. Tongue ad- nate. Branchial basket expanded, supported by 26 pairs of branchiostegals and jugoste- galia which broadly overlap along ventral midline. Urohyal split into two slender filaments for about 90% of its length. Tip of lower jaw and lateral skin folds of upper jaw papillose, as in C. eristigmus.
Teeth small and pointed (Fig. 2b). Intermaxillary teeth comprising two or three pairs partially covered by skin folds, largest anteriorly, followed by from four to six pairs of bi- serial vomerine teeth. Lower jaw teeth uniserial and small, about 10 to 15 on each side.
Preoperculomandibular, temporal, postorbital, suborbital, and supraorbital series of head pores present, not unlike those of C. eristigmus (Fig. lb) in number and position. Lateral line (of the left side of holotype) beginning on head, with 10 pores before gill opening, 87 to anus, and 157 total pores ending 0.2 head lengths from tail tip. Dorsal fin origin on head, above and slightly behind rictus; median fins ending less than a snout
Table 3. Callechelys galapagensis n. sp., counts, and proportions in thousandths, of holotype and 3 para- types; mean, and 95% confidence limits of the mean, and range.
|
X |
95% C. L. |
range |
||
|
Total length (mm) |
248-818 mm |
|||
|
Vertebrae |
172 |
169.4-174.6 |
170-174 |
|
|
(thousandths of total length) |
||||
|
Head |
76 |
67-85 |
69-82 |
|
|
Trunk |
478 |
456-499 |
463-494 |
|
|
TaU |
444 |
(thousandths |
432-456 ; of head length) |
437-455 |
|
Dorsal fin origin |
325 |
293-357 |
312-355 |
|
|
Snout |
132 |
127-138 |
128-137 |
|
|
Upper jaw |
248 |
194-302 |
197-269 |
|
|
Eye |
55 |
42-68 |
46-66 |
|
|
Interorbital |
103 |
80-126 |
81-112 |
|
|
Left gill opening length |
178 |
115-240 |
127-214 |
|
|
Isthmus |
109 |
71-148 |
76-133 |
|
|
Depth behind gill opening |
418 |
293-544 |
349-506 |
|
|
Depth at anus |
352 |
226-479 |
289-460 |
|
|
Width behind gill opening |
252 |
170-334 |
203-319 |
|
|
Width at anus |
226 |
158-293 |
178-272 |
20
length before tail tip. Fin rays in dorsal 520, anal 230 (counted from a radiograph of holo- type).
Gill arches and hyoid apparatus of the largest paratype (UCLA 64-40) removed and stained. Configuration and condition of the gill arch members like that of C. eristigmus except that the upper and lower pharyngeal tooth plates are nearly equal in length, and oblong rather than elongate (the lower pharyngeal plate of C. eristigmus is larger and more slender than the upper).
B
Figure 3a. Callechelvs galapagensis n. sp., paratype, UCLA 64-40, 767 mm total length, b. Callechehs galapa- gensis n. sp., a darkly colored paratype, UCLA 67-33, 248 mm total length.
Color in alcohol mostly cream, overlain with numerous dark oblong markings that vary in length from the size of the eye to the length of the upper jaw. These spots extend onto median fins and become densely aggregated on chin and top and sides of head. Ven- tral and dorsal surfaces more spotted than flanks, which have a row of small spots une- venly distributed along midline. The smallest paratype (Fig. 3b) differs from the other types in having a chocolate brown background coloration, although the spotting is sim- ilar.
f/vmo/ogy.— Named galapagensis, for the locality at which all known specimens were collected.
Material examined.— \\o\o{y\>Q: SIO 72-1, formerly UCLA 64-39, an 818 mm adult from the Galapagos Islands, Isla Santa Cruz, north shore, off small cove. Taken with Chemfish and SCUBA over a sand, rock, and sparse coral bottom in ten meters by B. W. Walker and E. S. Hobson on 24 February 1964. Paratypes: all from the Galapagos Is- lands. USNM 89728, 1(312), Isla Santa Maria, Black Beach Anchorage. UCLA 64-40, 1(767), Isla Santa Cruz, North Coast. UCLA 67-33, 1(248), Isla San Salvador, James Bay.
Callechelvs cliffi Bohlke and Briggs Figs.'2c, 4,"5;Tables 1,4,5 Callechelys cliffi Bohlke and Briggs, 1954: 275. Fraile Bay (Los Frailes), Gulf of Califor- nia.
Description.— Counts and proportions of the holotype are given in Table 1. Propor- tions of several juvenile and adult specimens are given in Table 4. The following descrip- tion is based on the adult specimens.
21
Body laterally compressed throughout its length, tapering posteriorly to a point. Depth behind gill openings 23 times and at anus 27 in total length; width behind gill openings 43.5 and at anus 45 in total length. Head and trunk 1.7, head 10.7 in total length. Snout acute, rounded at tip. Lower jaw included, tip reaches level of anterior nos- trils. Eye small, about as long as anterior nostril base. Posterior nostrils open into mouth, visible externally as a slit. Surface of head, trunk, and tail wrinkled (except top and sides of anterior portion of head smooth), becoming smoother on flanks posteriorly, as in C. ga- lapagemis. Tongue adnate. Branchial basket expanded, supported by 26 pairs of bran- chiostegals and jugostegalia which broadly overlap along ventral midline. Urohyal split into two slender filaments for ca. 80% of its length. Tip of lower jaw and anterolateral skin folds of upper jaw hghtly papillose (Fig. 2c).
t'-.<i»itr'6to.>ftiwi».JtAt.M^;lri»itLyyji>s».^
Figure 4. Adult of Callechelys cliffi, SIO 62-42, 455 mm total length.
Teeth small and pointed (Fig. 2c) uniserial in jaws. Two anterior pairs of inter- maxillary teeth hidden by skin folds of underside of snout, followed by a patch of six to seven intermaxillary teeth joined posteriorly to uniserial vomerine row.
Preoperculomandibular, temporal, postorbital, and supraorbital pore series present. Lateral line beginning on head with ten pores before gill opening, 86 to anus, and 151 to- tal pores, ending 0.3 head lengths from tail tip (SIO 62-42). Dorsal fin origin on head, above and slightly behind rictus; median fins end about a snout length before tail tip. Fin rays in dorsal 457, anal 205 (from radiograph of UCLA 63-45).
Gill arches and hyoid apparatus of two specimens (SIO 61-247, 65-281) removed and stained. The configuration and condition of the gill arch members is similar to that of C galapagensis (see description) in that the upper and lower pharyngeal tooth plates are nearly equal in length and oblong, rather than elongate and unequal as in C ehstigmus.
Color in alcohol tan, overlain with numerous fine brown spots on body and fins. Me- dian fins margined in white. Tips of snout, lower jaw, and tail cream-colored.
Table 4. Callechelys cliffi Bohlke and Briggs, counts, and proportions in thousandths, mean, 95% confidence limits of the mean, and range.
|
X |
95% C. L. |
range |
n |
|
Total length (mm) |
97.5-455 mm |
8 |
|
|
154-455 mm |
5 |
||
|
Vertebrae 154.9 |
153.4-156.5 |
149-158 |
14 |
|
(thousandths of total length) |
|||
|
Head 93 |
84-101 |
77-108 |
8 |
|
Trunk 474 |
459-488 |
441-496 |
8 |
|
Tail 434 |
426-442 |
418-450 |
8 |
|
(thousandths of head length) |
|||
|
Dorsal fin origin 4 1 3 |
351-474 |
363-480 |
5 |
|
Snout 142 |
123-161 |
121-170 |
5 |
|
Upper jaw 311 |
294-329 |
294-340 |
5 |
|
Eye 61 |
54-68 |
53-74 |
5 |
|
Isthmus 97 |
79-115 |
74-115 |
5 |
|
Depth behind gjU opening 494 |
416-573 |
351-568 |
5 |
|
Depth at anus 429 |
370-488 |
330-502 |
5 |
22
Remarks.— Out material includes a single collection (SIO 67-40) which contains a series of individuals from newly settled juveniles to adults. This series displays the juve- nile to adult color transformation and was compared with the holotype of C cliffi. Smaller specimens in the series were identical with the type in coloration, pore pattern, and morphometry.
Material examined— Mexico, Baja California Sur, Golfo de California— Bahia Los Frailes, SU 47521, 1(93.5 mm), the holotype. Punta Pulmo, SIO 61-247, 1(218). Punta San Telmo, SIO 65-281, 1(298). Buena Vista, UCLA 63-45, 1(382). Mexico, Nayarit, Bahia de Banderas, SIO 62-42, 1(455). Panama, Archipielago de las Perlas, Isla Saboga, SIO 67-40, 9(80-154).
DISCUSSION
We recognize 15 tropical and subtropical species in the genus Callechelys. C. guiche- noti Kaup, the generic type, is considered by us to be a junior synonym of C marmoratus (Bleeker, 1853). Kaup's (1856) description and Pellegrin's (1912) redescription of the type of C guichenoti, a 475 mm specimen from Tahiti, do not separate it from adults of C. marmoratus. Furthermore, recent extensive collecting efforts in Tahiti and the Southern Caroline Archipelago (by the Vanderbilt Foundation, J. E. Randall, and others) using im- proved ichthyocides have obtained numerous specimens of C. marmoratus and C. melano- taenius Bleeker. It is highly unlikely that C. guichenoti, if indeed distinct, would not have been taken in the various habitats sampled. Smith (1957: 838; 1962) also suspected C guichenoti to be a synonym of C. marmoratus, but was incorrect in considering C. hiteus Snyder conspecific with C. marmoratus.
Table 5. Vertebral number and tail length of the species of Callechelys.
|
Tail/SL |
Vertebrae |
Location |
Source |
|
|
C. bilinearis Kanazawa |
.3642 |
162 |
West Atlantic |
Kanazawa, 1952; this study |
|
C. bitaeniatus (Peters) |
.385 |
E. Africa, Mombasa |
Storey, 1939 |
|
|
C. cliffi Bohlke & Briggs |
.434 |
155 |
Eastern Pacific |
this study |
|
C. eristigmus sp. nov. |
.295 |
158 |
Eastern Pacific |
this study |
|
C. galapagensis sp. nov. |
.444 |
172 |
Galapagos Is. |
this study |
|
C. holochromus (Ginsburg) |
.333 |
Gulf of Mexico |
Ginsburg, 1951 |
|
|
C. leucopterus (Cadenat) |
.431-.475 164 |
Eastern Atlantic |
Blache and Cadenat, 1971 |
|
|
C. luteus Snyder |
.415 • 345; .282; .385^ |
213 |
Hawaii |
Gosline, 1951 |
|
C. marmoratus (Bleeker) |
180 |
West Pacific |
Storey, 1939; this study |
|
|
C. melanotaenius Bleeker |
203 |
West Pacific |
Storey, 1939; this study |
|
|
C. muraena Jordan & Evermann |
141^ |
West Atlantic |
Storey, 1939; this study |
|
|
C. nebulosus Smith |
.408 |
178^ |
Red Sea |
this study |
|
C. perryae Storey |
.328 |
Gulf of Mexico |
Storey, 1939; Blache and |
|
|
Cadenat, 1971 |
||||
|
C. perryae Storey |
.310 |
179 170^ |
Eastern Atlantic |
Blache and Cadenat, 1971 |
|
C. springeri (Ginsburg) |
.350 |
Gulf of Mexico |
Ginsburg 1951 |
|
|
C. striatus Smith |
.304 |
192 |
Red Sea |
this study |
Rounded mean value Type specimen
Characters currently used for species separation in this genus include the coloration, body depth, preanal length, and vertebral number (Table 5). The angle of the gill open- ing, sometimes used as a character (Storey 1939), is of little use, because of variability. The species most closely related to the eastern Pacific species C cliffi and C. eristigmus ap- pear to be C. muraena Jordan and Evermann and C perryae Storey, respectively. The re- markable similarity of each species pair is evidenced in the body depth and taper, color- ation, preanal length, and certain osteological characters. The members of each pair are, however, separable by vertebral number. A preliminary osteological study of several spe- cies of Callechelys and closely related genera has revealed trenchant differences in the urohyal and pectoral girdle. The urohyal is either a simple slender filament (in C eris- tigmus, C. marmoratus, and C. melanotaenius) or is split posteriorly into two slender diver-
23
g = C. galapagensis e= C. eristigmus
c = C. cliffi
Figure 5. Distribution of the eastern Pacific species of Callechelvs.
gent rays (in C. clijfi, C. galapagensis, and C. muraena). The pectoral girdle, as in most ophichthids that lack pectoral fins, is quite reduced, consisting of a slender cleithrum, supracleithrum, and small rodlike coracoid and scapula (?). Certain species of Callechelvs (C. eristigmus, C. marmoratus, and C melanotaenius) however, have lost the scapula, whereas others (C hi linearis, C. cliffi, C. galapagensis, C. luteus, C. muraena, and C. nebu- losus) have retained it. The retention of the scapula, along with the simple urohyal, may represent the generalized condition in Callechelys. The similarity of the New World forms, as well as their dissimilarity to other Indo-west Pacific species, strongly suggests a common ancestry prior to the closure of the middle American seaway. C. galapagensis ap- pears most similar to the central Pacific C. luteus Snyder, but differs in having fewer ver- tebrae, a deeper body, and a spotted anal fin. (Snyder (1904: 517) described the type as having "fins colored like the body"; our specimen, SIO 68-497, 1038 mm, has an un- spotted anal fin.) None of the three Atlantic species shows a close resemblance to C ga- lapagensis. On the basis of present evidence we therefore suggest that the three eastern
24
Pacific species of Callechelys have had two separate histories, with one species arising from a Pacific ancestor and the other two with a common New World ancestry.
ACKNOWLEDGMENTS
Carl L. Hubbs read the manuscript critically and Elizabeth Parker prepared the illustrations. For per- mission to utilize specimens in their care, thanks are due: William A. Bussing, Universidad de Costa Rica; Wil- liam N. Eschmeyer and Warren C. Freihofer, California Academy of Sciences: Lev Fishelson, Hebrew Univer- sity; C. Richard Robins, University of Miami Marine Laboratory; and Boyd W. Walker, University of California at Los Angeles.
This is a contribution from the Scripps Institution of Oceanography.
LITERATURE CITED
Blache, J. and J. Cadenat
1971. Contribution a la connaissance des Poissons anguilliformes de la cote occidentale d'Afrique. Dix- ieme note: les genre Mvrichihvs. Bascanichthvs et Callechelvs (Fam. des Ophichthidae). Bull, de IT.F.A.N., ser. A, 33(1): 158-201. Bohlke, J. E. and J. C. Briggs
1954. Callechelvs cliffi. a new ophichthid eel from the Gulf of California. Stanford Ichthyol. Bull. 4(4): 275-278. ■
Fowler, H. W.
1932. The fishes obtained by the Pinchot South Seas Expedition of 1929, with descriptions of one new genus and three new species. Proc. U.S.N.M., 80(6): 1-16.
1938. The fishes of the George Vanderbilt South Pacific Expedition, 1937. Zool. results, part 3. Monog. Acad. Nat. Sci. Philadelphia, no. 2. 349 p.
Ginsburg, I.
1951. The eels of the northern Gulf coast of the United States and some related species. Texas J. Sci. 3(3): 431-485.
Gosline, W. A.
1951. The osteology and classification of the ophichthid eels of the Hawaiian Islands. Pacific Sci. 5(4): 298- 320.
Kanazawa, R. H.
1952. More new species and new records of fishes from Bermuda. Fieldiana, Zool. 34(7): 71-100. Kaup, J. J.
1856. Catalogue of apodal fish, in . . . the British Museum. London, 163 p. Nelson, G. J.
1966. Gill arches of teleostean fishes of the order Anguilliformes. Pacific Sci., 20(4): 391-408. Pellegrin, J.
1912. Sur une collection de poissons des Nouvelles-Hebrides du Dr. Cailliot. Bull. Mus. Hist. Nat., Paris, 18(4): 205-207.
Smith, J. L. B.
1957. The fishes of Aldabra. Part IX. (with a new eel from East Africa). Ann. Mag. Nat. Hist., ser. 12, 10:833-842.
1962. Sand-dwelling eels of the Western Indian Ocean and the Red Sea. Rhodes Univ. Ichthyol. Bull. 24: 447-466.
Snyder, J. O.
1904. Catalogue of the shore fishes collected by the Steamer Albatross about the Hawaiian Islands in 1902. Bull. U.S. Fish Comm., Vol. 22 for 1902: 513-538. Storey, M. H.
1939. Contributions toward a revision of the ophichthyid eels. I. The genera Callechelvs and Bascanichthys, with descriptions of new species and notes on Mvrichihvs. Stanford Ichthyol. Bull., 1(3): 61-84.
Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92037
PALEONTOLOGY AND PALEOECOLOGY
OF THE SAN DIEGO FORMATION
IN NORTHWESTERN BAJA CALIFORNIA
ROBERT W. ROWLAND
TRANSACTIONS
OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
VOL. 17, NO. 3 9 JUNE 1972
PALEONTOLOGY AND PALEOECOLOGY
OF THE SAN DIEGO FORMATION
IN NORTHWESTERN BAJA CALIFORNIA
ROBERT W. ROWLAND
ABSTRACT-More than 100 species of invertebrate fossils were collected from gray sandstones of the San Diego Formation (Pliocene) exposed along the coast of northwestern Baja California. Paleoecologic eval- uation of the extant species and associated sediments suggests that the fauna accumulated at shallow sub- tidal depths near a submarine bank or low rocky headland. This feature, which probably formed the south- ern flank of the Pliocene San Diego embayment, was composed of a Miocene volcanic formation which underlies the fossiliferous strata.
The light-colored sandstone underlying the southwestern portion of San Diego County, California, is known as the San Diego Formation (Arnold and Arnold, 1902). Ex- tinct species indicate a Pliocene age for the formation and recent workers (ZuUo, 1969; Wi- cander, 1970) regard it as late Pliocene. The formation extends into Baja California, where highway construction exposed a number of fossiliferous sites (Fig. 1). This paper describes the fauna of these beds and presents a paleoenvironmental reconstruction of the area using geological and paleontological evidence.
The geology of the Tijuana-Rosarito Beach area was mapped and described by Minch (1967). In this area the San Diego Formation is underlain by a thick sequence of basalt, tuff, sandstone and breccia. Minch named these rocks the Rosarito Beach Formation; their age is middle Miocene (Hawkins, 1970; Minch, et al., 1970). Minch ( 1967) recognized two mem- bers in the San Diego Formation. The lower unit is composed of light gray to light brown sandstone containing several discontinuous lenses of conglomeratic sand. The upper mem- ber is a yellowish brown coarse sandstone containing beds of cobble conglomerate. Over- lying the San Diego Formation and capping the higher mesas is a reddish brown sandstone which Minch referred to the Lindavista Formation. Fossiliferous sand of Late Pleistocene age occurs on the low terraces along the coast (Valentine and Rowland, 1969).
Structurally the area consists of a series of elongate fault blocks which parallel the Paci- fic coast. These blocks are separated by high angle normal faults. Movement on the major faults has produced a west-tipped stepped structure and has separated the fossiliferous strata of the San Diego Formation into two belts. One lies within % mile of the ocean, and the other, less clearly defined, more than 1 Va miles inland. The relationship between the two belts is not clear, for no stratum can be correlated in both deposits.
Three collections of fossils (A-239, A-241, A-249) were made from the inland belt. Lo- cality A-252 is at the north end of the coastal belt, in the terrace which forms a base for the Pleistocene deposits of the Tijuana Playas area. The remaining localities are exposed in coastal bluffs and canyons from the International Border south to Rosarito Beach. Local- ities A-240, A-241, A-246, A-248, A-250 and A-251 are in basal conglomerates less than 20 feet above the base of the formation. Locality A-245 is 104 feet above locality A-240. The remaining localities are not in local superposition and their relative ages remain uncertain. Complete descriptions of the fossil localities have been presented elsewhere (Rowland. 1968).
METHODS
Thirteen localities were sampled semi-quantitatively. At each locality approximately 1.5 cubic feet of fossiliferous matrix was collected. The number of specimens of each species in this sample is recorded in Table 1 . The matrix was used for grain size analysis. The weight of sediment remaining on each sieve (from -3<}> to -1-4 l/2<^) was calculated as a percent of
SAN DIEGO see. NAT. HIST.. TRANS. 17(3): 25-32. 9 JUNE 197:
26
^
Figure 1. Map showing location of fossil localities sampled.
the total sample weight, then plotted against sieve size to produce size frequency histograms (Fig. 2). The collected material is deposited in the Geology Department, University of Cali- fornia, Davis.
Terminology for environmental parameters of wave exposure and water depth follows that ofValentine( 1961: Fig. 2). The littoral zone is delineated by the high and low tide lines and the inner sublittoral zone by the low tide line and the 25 fathom contour Une. Depth range, geographic range, and substrate requirements for the extant species were compiled from Grant and Gale (1931), Keen (1971), Morris (1966), Ricketts and Calvin ( 1968) and Valentine (1958).
RESULTS AND DISCUSSION
Megafossils collected are listed in Table 1. Extinct species form a significant portion of the fauna and are important in confirming the age of the strata. Common extinct species are: Dendraster ashlevi forma ynezensis, Acanthina eniersoni, Nassariiis gramniafus, Terehra martini. Ostrea erici, Anadara irilineata, Padnopecten dilleri, Patinopecten healyi. and Chlamys parmeleei. These species are characteristic of Pliocene strata in the San Diego, Ventura, and Santa Maria areas of California. The exact age of the San Diego Formation, to which the deposits in northwestern Baja California are assigned, is not known. The un- certainty arises partly from problems associated with establishing the Pliocene-Pleistocene boundary in the marine strata of California (see Bandy and Wilcoxon, 1970) and from com-
27
0
-1
o a
3
V
c
H(^ i-Ztp +3<t> +4(^ PAN
Figure 2. Size-frequency histograms of the sedimentary matrix at each fossil locality.
plexities within the formation itself. All the marine Pliocene deposits of western San Diego County are referred to the San Diego Formation, though the relationships between the strata of difterent areas are presently undeterminable. For example. Mission Valley and the Rose Canyon fault separate the San Diego Mesa with its Pliocene faunas from the Pliocene strata at Pacific Beach. These deposits may represent different times of deposition as discussed by Woodring and Bramlette (1950: 104-107), and surely they represent different dep- ositional environments. The Pacific Beach fauna is indicative of a sand-cobble, open coast environment, whereas quiet water faunas characterize the San Diego Mesa deposits. The collections at hand contain faunas whose components show aflfiliation to both of these biostratigraphic zones.
The fauna contains species representative of three environments. Calliostoma. Oce- nehra, Acanthina, Tegula, Thais, Ostrea, Hinnites, andArchitecfonia indicate a litloral-sub- littoral rocky coast area. Representatives of this group occur at 1 1 localities (see Tables 1 and 2). Tivela, Dentalium, Cadulus, Dendraster, and certain lucinid bivalves suggest a sub- littoral open coast environment with a sand substrate. This element is less abundant and occurs at four localities. Species of Nuculana, Panope, Spisula, Tresus, and Nassarius are predominant elements of a large fauna indicative of a fine mud or mud-sand substrate at
28
Tabic 1. FosmK Ironi llii' S.m Dicgu rornialion in northucsliTn H.i|a Calit'ornu
Spo
Antllo/oa.
Astrangia \:\. A. insignificata
Nomland. 1915 Balanophvllia clfgans Vernll.
1846 (iaNtropoda
Haliotis tulgens Pluhppi, 1845 Diodora a IT. D. iiuivquatts
(Sowcrby. 18351 CatUostonin costalum (Martyn.
17841 Calliostotna gemmuLitum
rarpcnicr. 1864 Calltosrorna kern Arnold. 1 910 Tegiila funebralis (A. Adams,
18541 Teguta gallinn (! orbes, 1850) AstToca inncqunlis (Martyn,
18741 Astraea undosa (Wood, 1828) Elilimn alT E. rulila Carpenter,
1864 Epitonium hellastriatum
(C'arpcnlcr. 1864) O/'alui \'anco%tatum Stearns,
1875 Tachvrhvmiiits erosus torma
imior Dall, 1919 Tt/rrittila iOopcri Carpenter.
1864 Tumtctta f^onostoina torni.i
hcmphilU Merrlam. 1941 Architecloitiva nohtis forma
discus drant and Gale. 1931 Cerilhtdea catifornka
(Haldeman. 18401 Calvptraea irtnmtlbrts Bmdenp.
1834 Trochito radians Lamark. 1822 Crcpidula onvx .Sowerby. 1824 l.unatia Icwisii ((iould. 1847) Polinices rccluzianus ( Deshayes,
18391 Trivin sutt^anea (Sowerby.
18321 h'usttriton aregonensis
(Redlield. 18461 Bursa californica Hinds, 1843 ' Ccralustonia foliata (Ctmelin,
18451 Jalun j estiva (Hinds, 1844) Ocenebra aft. O. fraseri
lOldroyd. 19201 Acanthina emersoni Hertlein
and Mlison. 1959 Tliais enmrf^nata (Deshayes,
18391 Thais lamellosa ic;melin. 17901 Cantharus aff C ringens
(Reeve. 18461 Kcllelia all. A. kellelii (1 orbes,
18501 Ainphissa el. A reticulata Dall.
1916 %Utrella ^ausapata (tioiild.
18541 Sassarius californianus
(Conrad. 18561 Xassarius Kraninialus (Dall.
19171 Nassariits mendieus forma
mdisputabllis (01dr..yd. 19271 Nassariits e t . .V pcrpinguis
(Hinds. 18441 Barharojusiis barbarcnsis (Trask.
18551 Psephaea oregonensis I Dall.
19071 (Hivelta btplteata (Sowerby.
1825) Olnelta pedrtmna (Conrad. 1855) Canceltaria fugleri (Arnold. 19071 Caneellaria tritonidea Clabb.
1866 Caneellaria rapa (Nomland. 1919 Conns eatifornieus (Hinds, I 844 1 Conus aff. C reeurvus
Broderip. 1833 Conus sp.
Tercbra niarltnt 1 nj.'lish. 1914 Terebra sp, Clavus ef. C empvrosia (Dall.
18991
I nlversin ol ( ahlnrnia, Dans I ossil 1 oialil les A series
239 240 241 243 244 245 246 247 24K 249 25(1 251 252
10
50
1
15 1
I 30
10
25
20
2 15
1
5 10
cf7
12 21
48
ef2 1
25 1
15
25 4 5
4 2 1
sublittoral depths or in a semi-protected area; this fauna occurs at 11 localities. Because Cerithidea califoniica. Bulla gouldiana, and Cryptomya californica are rare or absent in these collections but are dominant species in modern coastal lagoons (Warme, 1971), I be- lieve this last complex represents a sublittoral, open coast environment rather than a pro- tected lagoon.
The hydrographic regime indicated by the fossil faunas is paradoxical. Commonly a locality contains representatives of extant species whose present geographic ranges along
29
Tjblo 1 (Lunliruii.\l i
SpC.K-
Titrridac sp.
Ategasurcula carihiucruind
iGahh, lSh5l Mc^asurcula irvoniana Klabb.
1866) Volvolclla cylinJrua (( urpL-ntcr.
1S64) Acteocim a(t. .-1. inculla
((;ou!d and Carpcnlcr. 1857) Bivalvia
Acib castrcnsis (Hindv 1834) Sachi-m taphria (Dall. 18')6) Afiadara tritmeata (Conrad.
1856) CAycymeris cf. C subobsoleta
(CariK-nlLT. 1864) Myliltis c(. coalingcusis
Arnold, WIO Myfilus sp.
Ostrea erici McrlU-m. 1929 Ostrea vesperliiia (Conrad.
1854) Ostrta sp. Chlamys (Argopectcn) ctrcularis
(Sowcrby. 1835) Chlamys ha slata forma hcruia
(Gould. 1850) Chlamvs parmcleci { Dall.
189S) Chlamys sp. I.vropccten ccrroscnsis ((iahb.
1866) Pccicn helliis torma hemphilli
Dall. 1879 Pctlcnslcarnsi Dall. 1879 Pcclen (Palinopectcnl Jillcri
Dall, 1901 Pcctcn (Palinopectcnl hcaiyi
Arnold. 191)6 Hinnites sp.
Pododesmtis ccpio ((ira\. 1850) Cvclocardia californua (Dall.
1903) l.ucinonia annulata (Rcc-vc. 1850) l.ucina cxcavata Carpcntfr.
1857 Lucinisca nuiiallii (( onrad.
1837) Parvihicina tcnuisculpta
CarpL-nlcr. 1864 Thyasira hisccta (( onrad. 1849) Ijicvicardiuni quadra^cnarium
iConrad. 1837) Thcia <iiiiltoriim (Maui.'. 1823) Dosinia ponderosa (iray.
1 838 nc-u torni Chionc lI. elcsmerensis
1 n^hsh. 1914 Chionc fcrnandocnsis il nulisli.
1914 Prntofhaca lencrrima
(C arpi-n(cr. 1856) Spisula hemphilli (Dall. 1SM4) Madra sp. ^1 Mai tra sp. *2 \factra sp. #3 Trcsus nutlallii (( onrad.
1837) Garicdentula (Clabb. 1868-1869) Semclf ruhropuia Dall. 1871 Siliqua hnida ((onrad. 1837) Corbtita ^hhtjormis
(Sowcrby. 1833) Panopc abrupta (Conrad. 1849) Scaphopoda;
Dcntalium ncohcxagoniim
Sbarpand Cilsbry. 1897 Cadiilus fusijormis I'lKbry and
Sharp. 1897 Arthropodj
Balamn (BalamtsI sp. Balanus (Balamis) f^rcgaritis
(Conrad. 1856) I ».hinodi.Tmaia:
Dendraster ashlvyi lornia
ynczcnsis Ki-w. 1919 I Lhint)id spines hucidaris Ihourasii ( VaUni_icnncs.
1846) Vfrtcbrata;
Oircharodon arnoldi lordan.
1909
UnivcrsiCy of Calilorniu. Davis - I oiiil Localilics A scries 239 240 241 24? 244 245 246
249 250
4
21
|
15 |
•t |
5 |
1 |
|
|
25 |
3 |
20 |
5 |
|
|
2 |
1 1 II |
|||
|
5 |
3 |
26
13
14 1
13
13 19
5
25
25
37
5
19
5
8 I I
12
1 15
10
I
25
75 1
20
the western coast of North America do not overlap. For example. A-246 contains elements of all habitats as well as three Trivia sanguinea. which is living only in the Gulf of California and southward and a variety oi^ Dosinia ponderosa. At present Dosina is not found north of Scammon's Lagoon, Baja California. The same locality also yielded CaUiostoma cosiaium, Parvihicina tenuiscidpta and Chlamys hastata forma hericia, which range from southern California to Alaska, as well as Fusitriton oregonensis. a submergent. stenothermal, frigiphi- lic species which lives intertidally north of Oregon and is not found at depths less than 80
30
Table 2: Correlation between faunal elements and preferred sediment type. F ~ Faunal element present, S - Sediment peak developed
Locality Number
Sediment coarser tlian-2.0</)
Rocky substrate. Open coast fauna
Sediment between -2.0^ and +2.0 <^
Sand substrate. Open coast fauna
Sediment finer than +2.0 </>
Fine sand or mud substrate. Offshore fauna
A-239
A-240
A-241
A-243
A-244
A-245
S F
S F
S F
F (2 species)
S F
S F
S F
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S F
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fm. off southern California (Smith, 1970: 493). Depths of this magnitude are incompatible with environments indicated by the other species collected at this locality.
The concurrence of these northern and southern elements and the presence of Fusitri- ton is not readily explicable. Presumably nearshore upwelling of cool waters, perhaps into coastal waters warmer than presently found off southern California, was important in al- lowing these thermally anomalous species to coexist (Valentine and Emerson, 1961: 617- 618).
Data from the sedirnent analysis can be used to clarify the paleoecological inter- pretations. Sediment samples from the center of the study area are poorly sorted (Fig. 2). The distinct size concentrations of coarse and fine material suggest that these sediment sizes were not transported together (see, for example, the curve for locality A-246). The coarse fraction of the sediment may represent either lag gravels of underlying volcanic rocks or cobbles transported by storm waves. Presumably the sand- and silt-size material infiltrated the coarser material. Samples with the best sorting (A-249, A-250, and A-252) are found on
31
the margins of the area. The unimodal sand of A-249 impHes sorting by beach transport. At most locaUties the sediment size indicated by the size-frequency-histograms is compatible with the substrate on which the extant species are commonly found. For example, the fauna of locality A-246 contains species indicative of the three environments described above. The size-frequency distribution curve for this locality has peaks (-3</>, + \i> and -t-3.5</>). which correspond to the substrate of each of these environments. Interrelationships be- tween fauna and sediment are shown in Table 2. There is significant accord between the fauna and the sediment in 23 of the 29 cases. The heterogeneous nature of the fauna and the poor sorting of the sediments suggests that the environments that contributed to the fossil beds were in close proximity to the site of burial.
In summary, the environment of deposition of the Pliocene strata of northwestern Baja California can be reconstructed as follows: the Rosarito Beach Formation does not extend northward into California; presumably it formed the southern flank of the San Diego em- bayment as a bank or headland. The faunas studied accumulated on this feature at subti- dal. inner sublittoral depths in areas where patches of fine sand and mud were interposed between cobble beds and rocky exposures.
ACKNOWLEDGEMENTS
J. A. Minch. University of California. Riverside, provided me with an excellent field orientation. J. W. Valen- tine gave generously of his time and information throughout the study. Figures were drafted by L. Valentine and R. Darden.
LITERATURE CITED
Arnold, D., and R. Arnold
1902. Stratigraphy of southern California. J. Geol. 10: 117-138.
Bandy, O. L., and J. A. Wilcoxon
l'970. The Pliocene- Pleistocene boundary, Italy and California. Geol. Soc. Amer. Bull. 81: 2939-2948.
Grant, U. S., IV, and H. R. Gale
1931. Catalogue of the marine Pliocene and Pleistocene molluscs of California and adjacent regions. San Diego Soc. Nat. Hist. Memoir 1 Hawkins, J. W.
1970. Petrology and possible tectonic significance of Late Cenozoic volcanic rocks, southern California and Baja California. Geol. Soc. Amer. Bull. 81: 3323-3338.
Keen, A. M.
1 97 1. Sea shells of tropical west America. Stanford, Stanford Univ. Press.
Minch, J. A.
1967. Stratigraphy and structure of the Tijuana-Rosarito Beach area, northwestern Baja California. Mexico. Geol. Soc. Amer. Bull. 78: 1155-1178.
Minch, J. A., K. C. Schulte, and G. Hofman
1970. A middle Miocene age for the Rosarito Beach Formation in northwestern Baja California, Mexico. Geol. Soc. Amer. Bull. 81: 3149-3154.
Morris, P. A.
1966. A field guide to the shells of the Pacific coast and Hawaii. Boston, Houghton-Mifflin.
Ricketts, E. F., and J. Calvin
1968. Between Pacific tides. Revised by J. W. Hedgepeth. Stanford, Stanford Univ. Press. Rowland, R. W.
1968. Paleontology of the San Diego Formation in northwestern Baja California, Mexico. M.S. thesis. Uni- versity of California. Davis. 60 p.
Smith. J. T.
1970. Taxonomy, distribution and phylogeny of the Cymatiid gastropods Argobuccinum. Fusitriton, Me- diargo. and Priene. Bull. Amer. Paleo. 56: 445-573.
Valentine, J. W
1958. Paleoecologic molluscan geography of the Californian Pleistocene. Ph.D. dissertation. University of
California, Los Angeles. 458 p.
Valentine, J. W.
1961. Paleoecologic mollu-scan geography of the Californian Pleistocene. Univ. California Publ. Geol. Sci. 34: 309-442.
Valentine, J. W.. and W. K. Emerson
1961. Environmental interpretation of Pleistocene marine species: a discussion. J. Geol. 69: 616-618.
Valentine. J. W., and R. W. Rowland
1969. Pleistocene invertebrates from northwestern Baja California Del Norte, Mexico. California Acad. Sci.
32
Proc. 36: 511-530.
Warme, J. E.
1971. Paleoecological aspects of a modern coastal lagoon. Univ. California Publ. Geol. Sci. 87: 1-131.
Wicander, E. R.
1970. Planktonic foraminifera of the San Diego Formation, p. 105-117. In, Pacific slope geology of northern Baja California and adjacent Alta California. Amer. Assoc. Petrol. Geol. (Pacific Section) Fall Field Trip Guidebook.
Woodring, W. P., and M. N. Bramlette
1950. Geology and paleontology of the Santa Maria district, California. U. S. Geol. Survey Prof. Paper 222: 1-185(1951). Zullo, V. A.
1969. Thoracic Cirripedia of the San Diego Formation, San Diego County, California. Los Angeles Co. Mus. Contr. Sci. 159: 1-25.
Department of Geology, University of California, Davis, California, 95616
5»a/
Lip V .^'^ HARVARQ
SEISMIC RISK IN SAN DIEGO
ROBERT B. McEUEN AND CHARLES J. PINCKNEY
TRANSACTIONS
OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
VOL. 17, NO. 4 19 JULY 1972
SEISMIC RISK IN SAN DIEGO
ROBERT B. McEUEN AND CHARLES J. PINCKNEY
ABSTRACT.— Data from artificial earth satellites suggest that the regional shear stress responsible for earth- quakes is relatively high in the San Diego region. The direction of this stress is related to the orientation of the East Pacific Rise and the Gorda Rise. The apparent nonequivalence of strain accumulation to release along active faults northeast of San Diego also suggests that shear stress is accumulating over a wide zone and that seismic activity may occur on adjoining but presently less active faults.
Maximum credible earthquake magnitudes for San Diego proper and for the San Clemente Island fault zone are 6.8 and 7.7. respectively. These events are highly unlikely but should be considered in designing critical structures such as nuclear power plants. Regarding probable earthquakes, San Diego falls in the sec- ond most active of six regional zones in the United States in terms of strain release and in the most active of three zones in terms of regional seismic risk. In the recent past, how ever, most of the regional strain energy has been released outside the immediate San Diego area. Our analysis of the mechanics of strain release indicates that San Diego proper will experience an acceleration of 0.2 g on worse ground approximately every 60 years. The area ofwor.se ground is around the bays, where a two-fold amplification of bedrock acceleration could occur. The most likely source for this acceleration is the Elsinore fault.
A magnitude 6.3 or greater earthquake within the Continental Borderland could produce seismic sea waves capable of inundating San Diego's low lying coastal areas, but the occurrence of such an event is un- likely.
The purpose of this paper is to define seismic risk in San Diego, CaUfornia. We have attempted to strike a balance between an "it couldn't happen here" attitude and one that states "it's only a matter of time." Most of the data on which our conclusions are based are available in the literature. Dr. Charles F. Richter's (1959) comment sets the stage for the discussion which follows:
"There has been a general impression that earthquake risk does not exist at San Diego, historical records to
the contrary being forgotten or ignored. Older structures were erected with no close attention to soundness. During and since World War II, population has increased enormously, and the city area has expanded at a pace hardly consistent with careful construction and inspection. Fortunately most of this expansion has been over the higher ground..."
SEISMOTECTONICS
The seismotectonic framework of the San Diego area can be best understood by ana- lyzing seismotectonics on a global scale and by then studying in more detail those parts that have direct bearing on regional and local seismicity.
GLOBAL SEISMOTECTONICS
The seismic stresses responsible for earthquakes are thought to originate in the up- welling of hot light material of the earth's mantle. As this material convects it causes hori- zontal stresses in the earth's crust. The presence of such convection cells below the crust is indicated by slight changes in density of the material undergoing convection. These density variations in the earth cause deviations in the orbits of artificial satellites. Figure 1. shows satellite-deduced density variations for regions of high seismic activity (Schwiderski. 1968).
The Western Pacific (Fig. la) represents one of the most seismically active regions in the world. Here, zones of maximum seismic activity fall between low density areas presum- ably indicative of upwelling and high density areas indicative of convection downturn. Along the western coast of North and South America (Fig. lb) the zone of seismic activity also lies between an area of convective upwelling and downturn. This eff"ect is pronounced along the western coast of South America and we believe the western coast of North Amer- ica is being influenced by similar convective stress. But, the magnitude of this stress appears to be less than in the high seismicity zones of the Western Pacific or along the western coast of South America. Note, particularly, that the zones of seismic activity, almost without ex- ception, occur where the rate of change of density at the mantle surface is a maximum, that
SAN DIEGO SOC. NAT. HIST.. TRANS. 17(4): 33-62, 19 JULY 1972
34
30'
0 -
30-
L EGE ND X SHAL LOW DEPTH O INTERMEDIATE DE PTH • GREAT DEPTH
Figure 1. Contour map of density anomaly p' (in g/(dm)"^) at the surface of the mantle. Contour lines change by 8p' = 1.2. Earthquakes after Gutenberg and Richter (1954). a. Western Pacific showing earthquake zones along unstable strips between low-density sources and high-density sinks, b. Eastern Pacific showing earthquake zones along unstable strip between low-density sources and high-density sinks.
is, where the contour lines in Figure 1 are most closely spaced. San Diego occurs in such an area.
REGIONAL SEISMOTECTONICS
Figure 2 shows regional tectonic features thought to have direct bearing on the seismi- city of San Diego and adjoining areas. Figure 3 shows locations of earthquake epicenters for that portion of the area lying south of 34°N latitude. This area can be located on Figure lb by noting where the 120°W longitude line intersects the western coast of North America.
Between the zone marked East Pacific Rise at the bottom of Figure 2 and the zone marked Gorda Rise at the top, there exists a series of en echelon faults extending from the Tamayo fracture zone to the San Andreas Fault Zone. All these faults have a right-lateral sense of displacement, with the eastern side moving southeast relative to the western side.
Ridge crests, such as the East Pacific Rise and the Gorda Rise, are areas in which new oceanic crust is being created. Molten material presumably wells up within these zones and in so doing shoulders aside older material. As this process is repeated the area on both sides of the ridge crest moves laterally. Records of seismic activity indicate that zones of shallow earthquakes are associated with ridge crests; these zones also tend to align between areas of mantle upwelling and downturning as delineated by upper-mantle density anomalies (Schwiderski. 1968). The apparent extension of the East Pacific Rise into the Basin and Range Province (Fig. 2) follows the zone of maximum upper-mantle density change (Fig. lb).
The large arrows perpendicular to the strike of the East Pacific Rise and the Gorda
35
Figure 2. Fractures and spreading centers along part of the Pacific Coast of North America. S.D. marks the location of San Diego. Oceanic fracture zones (FZ) and continental faults (F) are solid black lines, dashed where uncertain. S.A.F.— San Andreas Fault; D.V.F.— Death Valley-Furnace Creek Wash Fault; O.V.F.-Owens Valley Fault; G.F.— Garlock Fault; E.F.— Elsinore Fault; S.J.F.— San Jose Fault; A.B.F.— Agua Blanca Fault; S.R.F.— Santa Rosalia Fault; S.C.F.— San Clemente Fault; R.F.— Rampart Fault. Post- ulated spreading centers along the crest of the East Pacific Rise and its possible continuation into the continent shown in gray. Representation of spreading centers in the Basin and Ranges is sym- bolic, indicating a region of crustal extension (Modified from Elders, et al., 1970).
Rise indicate the relative direction in which stress is appHed due to forces produced along these spreading centers (Fig. 2). The right-lateral movement of the series of faults is accom-
36
modating this stress, and one is tempted to consider the whole zone of fauhing as a shear set. Gastil et al. (in press) note, however, this simphstic view is not consistent with the right- stepping nature of the en echelon fault breaks.
In the San Diego region, the zone of possible stress accumulation reaches its widest extent in an area bounded on the east by the San Andreas fault and on the west by the Rampart fault, which marks the western hmit of the Cahfornia Continental Borderland.
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Figure 3. Earthquake epicenters with magnitudes of 4 or greater between 1958 and 1968 (from Gastil, Allison, and Phillips, in press).
Earthquakes occur in areas where differential stress exceeds the shearing resistance of the material in the area, and rupture occurs. If diff"erential stress is applied across the broad zone of en echelon faults strain should be occurring throughout the zone. A necessary con- straint to a surface rupture of considerable length is that the rate of surface strain accumula- tion must be a maximum in the immediate zone of faulting. If not, and large surficial plates are moving in opposite directions tangential to the fault (Fig. 2), the faulting must spread through time over a wide lateral area. With these thoughts in mind, let us examine the strain-accumulation and strain-release history of the onshore regions adjoining San Diego.
Onshore strain accumulation. To determine strain accumulation, geodetic surveys
37
should be carried out in intervals between earthquakes. Following the magnitude 7. 1 Impe- rial Valley earthquake of 1940, the Imperial Valley triangulation network was resurveyed; a second resurvey was made in 1954. and a third in 1967. Scholz and Fitch ( 1969). summa- rized the data obtained in the area of the Imperial fault, which ruptured along 40 miles of its length in 1940. and therefore represents a zone along which strain accumulaton should at- tain a local maximum. They concluded that slip occurred along the Imperial fault between surveys, releasing about 15 per cent of the accumulated strain. Their slip-corrected data (Fig. 4) verifies that shear strain is accumulating at a higher rate near the fault. The data for the 1 94 1 - 1 954 period are shown in vector form in Figure 5a. The fact that the shear strain is appreciable at considerable distance from the fault zone led Scholz and Fitch ( 1969) to state that "the Elsinore. San Jacinto, and Mission Banning Creek faults... may, in fact, testify to a 'spreading' of the fault zone due to a nonequivalence of strain accumulation and release..."
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Figure 4. Strain accumulation parallel to the Imperial Fault versus distance from the fault for the period 1941- 1954. The data has been corrected for the observed slip and superimposed on one side of the fault (Scholz and Fitch. 1969).
Savage (1970) shows that the strain that accumulated between 1941 and 1967 is ap- proximately twice that accumulated between 1941 and 1954 and concludes that for the Im- perial Valley triangulation network the strain rate is about 0.4-1-0.1 /x strain/yr over a zone 100 km (63 miles) wide.
Onshore strain release. —Strain release can be obtained bv direct measurement if good geodetic control is available prior to the release of strain by an earthquake. Figure 5b shows retriangulation results obtained following the 1940 Imperial Valley earthquake. Such good geodetic control in the past has been the exception rather than the rule, and seismologists have had to rely on empirical relationships to establish probable strain release associated with earthquakes.
Figure 6 shows a strain-release map derived from a two year study of 28.000 earth- quakes in the conterminous United States, including 16,000 in California. The map is useful in that it shows the relative rate of seismotectonic activity in various areas. Note that a zone of maximum seismotectonic activity lies just east of San Diego and that the San Diego area falls in the second most active of zones.
Offshore faiilting.-Moore (1969) published a structural map of the California Conti- nental Borderland based largely upon the interpretation of seismic reflection profiles. These profiles commonly show folded structure within strata and either directly or indirectly the location of faults. He concluded that the primary offshore structural pattern comprises two
38
^Coltpotr ia
\
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El Ceniro
1941-1954
MILES 10 20
30
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in feet
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1939-1941
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^ ^
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Figure 5. a, Retriangulation strain-accumulation results, U.S. Coast and Geodetic Survey, Imperial Valley, 1941- 1954. b, Retriangulation strain-release results, U.S. Coast and Geodetic Survey, Imperial Valley, 1939-1941 [after Whitten by C. R. Allen] (Ritcher, 1958).
sets of faults, a set trending northwest and another east-northeast. The northwest trend so predominant onshore clearly carries through to most of the Borderland as the principal set and, where topographic offsets are well enough developed to be significant, movement appears to be right-lateral (Fig. 7). This conclusion is consistent with first-motion studies of earthquakes which, with one important exception, indicate right-lateral movement on northwest trending faults (Gutenberg, 1941; Allen, 1960). The exception is the 5.9 magni- tude earthquake that occurred off the southeast tip of San Clemente Island in 1951. First motion for this earthquake can only be explained by assigning it a large component of dip- shp movement (Allen, 1960).
The dominant fault of the inner zone of major northwest trending faults is the San Cle- mente Island fault extending from the eastern side of San Clemente Island to the Cabo Col- nett area of Baja California, Mexico. Another major fault forming the eastern face of Santa Catalina Island may be continuous with a fault along the western boundary of the San Diego Trough. Moore (1969) suggested, based on the sedimentation and structure of the Borderland and records of modern earthquake epicenters, that about 1 million years ago formation or rejuvenation of the Agua Blanca fault initiated strike-slip faulting in the inner
39
zone of the Borderland, formed new inshore basins, and realigned drainage systems, form- ing centers of deposition for Pleistocene turbidity currents. This latest movement continues today, as shown by the modern seismic activity of the inner zone, but perhaps with abated intensity, inasmuch as deformation of Pleistocene sediment in the inner basis is uncommon. Wiegand ( 1970) suggested that the Newport-Inglewood fault has an offshore extension of major proportion. Although there are faults observable offshore as far south as Encinitas that can be extrapolated northward in such a way as to merge with the Newport-Inglewood trend, there is insufficient evidence that these are continuous or that they involved offsets of the same order of magnitude as the major faults farther offshore.
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Figure 6. Strain release in the United States, 1900 to 1965, expressed as the equivalent number of magnitude 4 earthquakes/ 10,000 km766 years (from Algermissen, 1969).
LOCAL SEISMOTECTONICS
Strain /-e/ea^e— Earthquake epicenters recorded in the San Diego area are plotted on Figure 8. The data (Fig. 6) indicate that the energy associated with strain release in the San Diego area during the past 66 years should be equivalent to that produced by approximately 100 magnitude 4 earthquakes per 1,000 km- of surface area. Figure 9 gives a generalized rela- tionship between the Richter Magnitude and Modified-Mercalli Intensity. Within a 1,000 km- circle centered on downtown San Diego, only 12 earthquakes have been reported dur- ing the past 66 years. The magnitudes of these average less than 4 and their intensities aver- age about IV. We conclude that in the recent past most of the regional strain energy has been released outside the immediate San Diego area. Algermissen (1969) gives the average strain release per 1,000 km- for the entire Pacific Coast (west of 1 14° W longitude) as being equivalent to 12 magnitude 4 earthquakes per 66 year interval.
Surficial faulring.-The principal surficial faults in the San Diego area are shown on Figure 10. Many of these appear to be associated with past tectonic forces, but some of the northwest trending and north trending faults offset Holocene (less than 1 1 ,000 years old), as
40
30
I I L
NAUTICAL MILES
- VERIFIED LENGTH OF F
- DEPTH IN FATHOMS
Figure 7. Structure of the Continental Borderland and adjacent regions (modified from Moore. 1969).
well as late Pleistocene (less than 400,000 years old) sediments. The north trending parallel series of faults on Point Loma, as well as faults in the Rose Canyon area, offset Pleistocene sediments. These faults can typically be mapped for at least a few miles (see Buffington, 1964; Kennedy, 1969). There is a series of normal faults east of San Diego Bay that offset Pleistocene sediments. One of these, the La Nacion fault, offsets Pliocene sediments by over 230 ft. Pleistocene sediments by over 200 ft, and Holocene materials a few feet.
Faulting in basement rock.—\r\ areas covered by a veneer of sedimentary rock, changes in surface topography caused by faulting quickly become obscured by erosion or by depo- sition. For such areas, faulting is best delineated by changes in elevation of basement rock. In the parts of San Diego where batholithic rocks are absent, basement is represented by dense metavolcanic rocks of Jurassic age. Gravity data provide an excellent basis tor pre- dicting the elevation of this basement unit due to its high density relative to the overlying sediments (Elliott, 1970).
Location of probable basement faulting by analysis of gravity data is limited, since steep slopes on the ba.sement surface produce gravity anomalies which differ only slightly from those produced by near-vertical faulting. The inferred regional stress pattern dis- cussed earlier strongly suggests that primary basement faulting is responsible for the north- west trends evident in the gravity data in the San Diego Bay, Mission Bay, and Mount Sole- dad area.
Figure 1 1 shows probable basement faulting superimposed on the gravity data re- cently published by Elliott. The two primary and presumably right-lateral faults, indicated
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3 3' 00'
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Figure 8. Epicenter map of the San Diego area giving date (e.g. 11-4-25), Modified-Mercalli Intensity (e.g. IV M.M.), and Richter Magnitude (e.g. 3.4) when known. Circle shown has area of 1,000 square kilometers.
by the dashed Unes, form the edges of a zone which narrows to the northwest. Within this zone, secondary fauUing, indicated by the dotted hnes, may have occurred.
The right-lateral sense of the primary faults is suggested by the manner in which they offset the La JoUa Submarine Canyon (Buffmgton, 1964). The westernmost primary fault has some surface expression which has been mapped by Milow (see Buffmgton, 1964) and by Kennedy (1969). The right-lateral sense of this fault may be further indicated by offset topography along the eastern margin of Point Loma. Other geophysical data suggest that this fault continues to the south, where it parallels the western coast of Baja California (Allen et al., 1965). The easternmost of the primary faults has little surface expression. Rose Canyon notwithstanding. It can possibly be traced for a limited distance in the area north- west of Rose Canyon, and it may be correlated with faulting exposed east of Mission Bay. That motion along the primary fault set is not exclusively right-lateral is attested to by the pronounced gravity low in the region of San Diego Bay. This view is corroborated by the depths of basement rock in the area (Elliott, 1964). Vertical offset of basement rock in excess of a thousand feet is certainly consistent with geophysical and well data for the South Bay area.
Due to the convergence of the primary fault set, a zone of transitional stress occurs north of San Diego Bay. Compressional stress to the north may account for the anomalous elevation of Mount Soledad. It has been suggested that Mount Soledad represents the up- tilted edge of a block which contains Mission Bay as the downtilted counterpart (Peterson. 1970). The secondary faults, indicated by dotted lines on Figure II, allow for this possi- bility. The northernmost secondary fault is provided in order to allow for the possibility that Mount Soledad and Mission Bay represent a horst-graben set. These secondary faults are consistent with the gravity data and are placed along the strike of "positive" faults, as mapped by Milow (see Buffington. 1964). These "positive" faults have a direction of dip or relative vertical separation which is consistent with the gravity interpretation presented herein.
42
Wiegand (1970) analyzed selected geologic and geophysical data covering the area be- tween the two suggested primary basement faults shown on Figure 11. He concluded that primary faulting has occurred along the axis of San Diego Bay and proposes this fault may be an extension of the Newport-Inglewood fault zone to the north and the San Miguel fault to the south. The gravity data of Figure 1 1 do not support such faulting through San Diego Bay.
Not felt except by very lew under especially favoruble conditions
Felt only by a few persons at rest, especially on upper Hoors of buildings. Delicately suspended objects may swing.
Felt quite noticeably indoors, especially on upper floors of buildings, but many people do not recognize it as an earthquake. Standing motor cars may rt)ck alightly. Vibration like passing of truck. Duration estimated.
During the day felt indoors by many, iiuldoors by few. At night some awakened. Dishes, windows, doors dis- turbed; walls make creaking sound. Sensation like heavy truck striking building. Standing motor cars rock noticeably.
Fell by nearly everyone; many awakened. Some dishes, windows, etc., broken; a few instances of cracked plaster; unstable objects overturned. Disturbance of trees, poles and other tall objects sometime noticed. Pendulum clocks may stop.
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Felt by all; many frightened and run outdoors. Some ] or damaged chimneys. Damage slight.
;avy furniture moved; a few instances of fallen plaster
Vli
Everybody runs outdoors. Damage negligible in buildings of good design and construction; slight to moderate in well-built ordinary structures; considerable in poorly built or badly designed structures; some chimneys broken noticed by persons driving motor cars.
Vli
Damage sliglit in specially designed structures; considerable in ordinary substantial buildings with partial collapse; great in poorly built structures. Panel walls thrown out of frame structures. Fall of chimneys, factory stacks, columns, monuments, walls. Heavy furniture overturned. Sand and mud ejected in small amounts. Changes in well water. Persons driving motor cars disturbed.
Damage considerable in specially designed structures; well designed frame structures thrown out of plumb; great in substantial buildings, with partial collapse. Buildings shifted off foundations. Ground cracked conspicuously. Underground pipes broken.
Some well-built wooden structures destroyed; most masonry and frame structures destroyed with foundations, ground badly cracked. Rails bent. Landslides considerable from river banks and steep slopes. Shifted sand and mud. Water splashed (slopped) over banks.
J
Figure 9. Modified Mercalli Intensity scale showing approximate relationship with ground acceleration and mag- nitude of shallow local earthquakes (from Linehan 1970).
43
SEISMIC RISK
The determination of seismic risk is fraught with uncertainties. To quantify these un- certainties is beyond the scope of this paper, but we have attempted to estimate the max- imum probable risk presented to the San Diego area by earthquake energy. An in- troduction to the probabiHstic approach has been recently presented by Esteva (1970). Dr. Clarence Allen (1964) in a discussion of the engineering implications of seismic geology
made the following comments:
"Seismic zoning maps for engineering purposes have usually been constructed on the basis of the earthquake history of a region, sometimes in combination with the locations of so-called "active" faults and related seismo-tectonic features. Indeed, these are normally the only items of pertinent information avail- able—however inadequate. It should be emphasized, however, that these data may be even far more in- adequate than most people realize. The difficulties and dangers in interpreting a relatively short recorded earthquake historv, as well as the problems in attempting to differentiate between active and inactive faults, have already been pointed out, together with the very widespread distribution of earthquake-induced ef- fects during a great shock. In addition, major after-shocks of a great earthquake are distributed over a far wider area than has generally been appreciated, and they constitute a hazard that may seemingly be quite unrelated to the local fault pattern. Potentially damaging after-shocks of the 1960 Chilean earthquake, for example, blanketed an area almost the size of California. It is significant that those countries with the long- est and most complete recorded earthquake histories are generally those in which the mapped zones of potential high seismic hazard are the broadest, and this lesson should be kept in mind by those persons attempting to construct new zoning maps or by engineers who are facing the same problems in regard to specific sites."
These comments apply to much of what follows.
FORMATIONS
SAN DIEGO
OTAY (NEW)
SWEE T WATER (NEW)
POWAY
□
3r LA JOIL A O
ROSARIO
o- metamorphic JJ;
^ AND GRANITIC - ROCKS "
INFERRED
CONCEALED
ANTICLINE
FAULT
SYNCLI NE
CONTACT
Figure 10. Principal surficial faults and related structures (from Artim and Pinckney, m press).
DEFINITIONS
It is of Utmost importance to define the terminology used in ascertaining seismic risk.
Maximum credible earl hquake.— This is the maximum earthquake that in our judg- ment appears capable of occurring. It is the maximum rational and believable event con- sistent with the known facts. While it is highly unlikely, it is still a believable event that could occur within the present geologic framework and present geologic epoch. No state-
44
O Dry Oil Well 35
(-2138) Top of Basement
0(-5236) \ -15
Figure 11. Probable basement faulting, Bouguer gravity map after Elliott (1970). Faulting; Secondary Basement Faulting.
Primary Basement
ment can be made with regard to its probability of occurrence, other than that it is finite (modified from Cluflfet al., 1969).
Maximum probable earthquake.— This is the maximum earthquake that might occur with a fairly high probability. The tectonic forces which cause it are reasonably well under- stood. Statistical data allow the prediction of a recurrence interval for this earthquake. For all but the most critical considerations, it is the maximum "design" earthquake.
Active fault.— An active fault is one that has moved in historic time or along which off'- set of Holocene materials can be demonstrated. If Holocene materials are not offset, but numerous epicenters have been recorded in or in close proximity to the fault, a classifica- tion of active may be used.
Potentially active fault.— A potentially active fault is one that offsets Pleistocene ma- terials, but for which offset of Holocene materials is lacking and for which seismic activity is nominal or absent.
REGIONAL RISK
Algermissen's regional risk map is reproduced in Figure 12. On this map San Diego is shown in the zone where "major destructive earthquakes may occur." This map is based on the following: the distribution of M.M. (Modified-Mercalli) intensities associated with the known seismic history of the United States; strain release in the United States since 1900; and the association of strain release patterns with large scale geologic features believed to be related to recent seismic activity. Since this map is based partly on maximum observed intensities, it is biased towards conditions expected on worse ground. The probable fre- quency of occurrence of damaging earthquakes in each zone was not considered in assign- ing ratings to the zones.
45
Figure 12. Seismic Risk (after Algermissen, 1969). Zone 0-No damage. Zone 1-Minor damage; distant earth- quakes may cause damage to structures with fundamental periods greater than 1.0 seconds, corresponds to in- tensities V and VI of the M.M. Scale. Zone 2-Moderate damage; corresponds to intensity VII of the M.M. Scale. Zone 3— Major damage; corresponds to intensity VIII and higher of the M.M. Scale.
LOCAL RISK
Zone 3, which includes the San Diego area, corresponds to intensity VIII and higher on the M.M. scale. Assuming that San Diego falls in the intensity VIII portion of the zone leads to the conclusion that it will experience an acceleration on worse ground of approximately 0.2 g (Fig. 9).
An acceleration of 0.2 g exceeds by only a factor of four the acceleration which San Diego in all probability repeatedly experiences; the isoseismal maps shown in Figure 13 indicate probable ground accelerations in San Diego of 0.05 g. Events of this size (i.e. mag- nitude 6.3) originating in the same general 10,000 km- area as the earthquakes plotted on Figure 13 can be expected to occur approximately once every 15 years. Note that if for the earthquakes shown on Figure 13 one calculates the expected acceleration directly from magnitude and distance considerations using the most recent empirical relationships, con- siderably lower probable acceleration is obtained (Esteva, 1970; Seed, Idriss, and Kiefer, 1969). This deviation may be explained in terms of the shallow depth at which events in Southern Cahfornia occur and local geology.
Seismic-input estimates. -The most difficult aspect of determining seismic risk is esti- mating the maximum energy which can be expected. Correlations between geological and seismological data must be used where statistically significant seismic data are lacking. Fig- ure 14 shows an idealized relationship between the length of the surface fault breaks occur- ring at the time of earthquake (determined geologically) and earthquake magnitude (deter- mined seismologically). The portion of the curve above magnitude 6.5 is based on a study of historic surface faulting in the continental United States and adjacent parts of Mexico car- ried out by Bonilla (1967). We have plotted on this figure the reported surface breaks and measured magnitudes of some important earthquakes. The size of the earthquakes plotted range from the great, magnitude 8.6, Chilean earthquake of 1960 where surface breakage occurred over a distance of 600 miles to the recent 6.6 magnitude San Fernando earthquake which had surface breakage of over 9 miles. This plot confirms that the stress drop across the slipped fault is the same for all large earthquakes; and therefore, that for a constant
46
Morch 19, I9S4
limilt of F«ll Area
CALIFORNIA
ARIZONA
J<f-
Aprll t, 196t , It: 2t: 5(9 P.S.T Mognitvd* 6.5 CAIIFORNIA
-3^
Figure 13. Borrego area earthquakes (Murphy and Cloud, 1956: Von Hake and Cloud, 1966). Stations reporting anomalously high intensity are indicated by black dots.
depth of faulting the total strain energy released is proportional to the length of surface breakage.
Maximum probable input from San Andreas system.— The work of Bonilla ( 1967) and Housner (1969) allows us to predict maximum probable earthquake magnitude for a given fault system by assuming a maximum probable length of surface breakage. For example, if one assumes for the Elsinore fault zone that surface breakage could occur along a zone 50 to 70 miles long, then the resultant magnitude would be 7.3. Such a surface break might be expected to have its southern limit near Vallecito Valley and its northern limit somewhere between Temecula and Lake Elsinore. Similarly, if one assumes for the San Jacinto fault zone that surface breakage could occur along a zone 150 to 190 miles long, then the result- ant magnitude would be 7.8. Such a surface break might be expected to have its northern limit between Riverside and San Bernardino and its southern limit between Imperial and the known southern limit of the Imperial fault in Mexico. The above discussed approx- imations are plotted on Figure 14 and shown in map view on Figure 15.
47
Figure 14. Idealized relation between length of surface breakage and magnitude of earthquake used for determination of maximum probable events on Elsinore and San Jacinto Faults. C = Chile (1960), A = Alaska (1964), S = San Francisco (1906), E = E1 Centre (1940), S.M. = San Miguel ( 1956), S.Fer. = San Fernando (1971) (Modified from Housner, 1969).
1000 500
100 50
10
I
1.0
0.5
0.1
|
1 |
1 |
T |
T |
1 |
r |
/•c- |
|
|
- |
1 = 2.25X10'* |
e^M |
--^. |
/a . - |
|||
|
SAN JACINTO |
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|
/ |
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I |
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, |
|||||
|
- ELSINORE |
/ |
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- |
EV /SM |
- |
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'- |
IP .*S.FER. /l |
; |
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= 1.82X10''e'*^ |
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2 3 4 5 6 7
Magn itude
8 9
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SAN DIEGO
20
1
SCALE OF MILES
Eorthquoke Epicenteri
a 6 0-69
A 55-59
A 5.0-54
• 4.5-4.9
• (1931-1968)
Figure 15. Ma.ximum probably surface breakage-Epicenters and faults from California Dept. Water Res. Bull. 1 16-2. Cross-hatched zone = 10,000 km'.
48
There is presently considerable debate as to the nature of the San Andreas fault in the area immediately south of the Salton Sea (see Fig. 16). Because the position of faults in that portion of the Imperial Valley is uncertain, estimates of maximum probable surface break- age along this part of the San Andreas fault are not presently feasible.
Figure 16. Faulting south of Salton Sea (from Elders et al., 1970).
Figure 17. which relates ground acceleration to epicentral distance, indicates that a magnitude 7.3 event on the Elsinore fault produces greater ground acceleration in San Diego than a magnitude 7.8 event on the San Jacinto fault. However, the duration of shak- ing for the magnitude 7.8 event can be expected to be 20 per cent greater than that pro- duced by the magnitude 7.3 event (Steinburgge, 1966). These relative comparisons are valid, but the value of ground acceleration for a given site can range widely from the "inter- mediate ground" values given in Figure 17. An order of magnitude variation in acceleration is feasible (Esteva, 1970). At San Diego, the slightly longer duration of expected shaking produced by the larger San Jacinto fault event does not result in total dehvered energy greater than that produced by the smaller event on the Elsinore fault.
The frequency of earthquakes in Imperial Valley has been graphed by Evernden (1970) in a form selected to reflect the repeat interval for earthquakes in a 10,000 km' area (Fig. 18). For comparative purposes Figure 15 shows a 10,000 km- zone 35 miles in width which extends southward from the town of San Jacinto to an area just west of the Laguna Salada in Baja California. From 1934-1971 this zone experienced five earthquakes having magnitudes greater than 6. This rate is consistent with the data of Figure 18. which can therefore be used to estimate repeat intervals for maximum probable events on the Elsinore and San Jacinto faults. Linear extrapolation to high magnitude, justified below magnitude 8, yields a repeat interval of approximately 60 years for the 7.3 event on the Elsinore and approximately 170 years for the 7.8 event on the San Jacinto.
Note that if the surface break on the Elsinore fault shown on Figure 15 is logical, and if the seismicity of the Imperial Valley can be applied to this area, then the Elsinore fault rep- resents the source of maximum risk to the San Diego area. The maximum probable event for this fault occurs more often and delivers more energy to the San Diego area than does
49
)0
a
i 6
o
Figure 17. Acceleration on intermediate ground as a function of epicentral distance and magnitude (after Esteva et al., 1964).
|
9= 981 cmAec^ R= Epicentrol Distance in Miles |
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7 8 ON SAN JACINTO |
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0 20 0 15
0 10
0 05
0 01
z o
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20 30 40 60 80 100
EPICENTRAL DISTANCE R, MILES
the maximum probable event for the San Jacinto fauU. The geologically short seismic his- tory for this fault does not, so far, corroborate this view. The San Jacinto fault poses an equivalent threat in cases where the induced failure is extremely sensitive to the duration of shaking.
Maximum credible input from ojfshore— On Figure 7, the maximum verified lengths of offshore faults are plotted. In order to be considered verified, two conditions must be met: the fault must have been positively identified on seismic profiles; and its extension between profiles must be consistent with submarine topography.
The largest fault within the California Borderland is the San Clemente Island fault, with a verified length of approximately 110 statute miles. The maximum credible earth- quake for the Borderland, produced by breakage of this fault over its entire verified length, would have a magnitude of 7.7. Since this fault is approximately the same distance from San Diego as the Elsinore fault, we conclude that the maximum credible off'shore event will produce approximately 50 per cent greater acceleration in San Diego then the maximum
Figure 18. Regional seismicity. Imperial Valley, California, 1934-1963 (Everden. 1970).
MAGNfTUOE
50
I 1-6 t 1.2
u _0
0) 0.8 >
"5
Q.
1/1
0.4 0
|
1.6 1.2 0.8 0.4 0 |
1.6 1.2 0.8 0.4 0 |
^ |
1.6 1.2 0.8 0.4 0 |
i\ |
|||||||||||
|
fi |
\ |
\ |
S . |
fi |
\ |
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|
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'^'>_ |
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. |
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||||||||
|
A |
/^ |
/ |
^>« |
t |
0 0.5 1.0 1.5 0 0.5 1.0 1.5 Period— Sec. Period— Sec.
0 0,5 1.0 1.5 Period —Sec.
0 0.5 1.0 1.5 Period — Sec.
MAX. ACCN.= 0.05g
Figure 19. Computed response spectra for sand and gravel deposit (from Seed, 1969). Predominate period of bed- rock motion = 0.35 seconds; equivalent damping = 5%.
probable event on the Elsinore. It would also cause a greater duration of shaking.
Tsunami (seismic sea wave) risk.— ]oy ( 1968) discussed tsunamis and their occurrence along the San Diego County coast. He pointed out that the relatively wide Continental Bor- derland off the coast has historically acted as an effective diffuser and reflector of the energy which arrives from remotely generated tsunamis. Damage associated with remotely gener- ated tsunamis, therefore, will be most likely confined to small craft in the harbor, although some waterfront structures may also be affected.
Locally generated tsunamis risk is difficult to assess. Tsunami generation requires a rapid dislocation of the sea surface or bed over a very large area (thousands of square miles). This size dislocation is not likely to occur if the source earthquake has magnitude less than 6.3 (lida, 1970). Most major dislocations of the sea surface or bed are thought to be associated with fault movement of the "dip-slip" type. This type motion seems to have been associated with the 5.9 magnitude earthquake that occurred near San Clemente in 1951. Generation times for tsunami producing dislocations can be as large as several minutes. An earthquake could therefore initiate a large submarine landslide, which could then become a tsunami source.
Seven per cent of Southern Cahfornia earthquakes have submarine epicenters (Cle- ments and Emery, 1947), and yet only two or three locally generated tsunamis are known to have occurred off Southern California since 1800, none in the San Diego area. Joy (1968) points out that if the San Clemente Island fault and the Agua Blanca fault in Mexico (Fig. 2) "actually constitute a single larger feature, ... it could represent a standing threat to San Diego County." He concluded, however, that "it is entirely speculative to suggest at this time that any significant threat exists. Certainly the nonoccurrence of tsunamis generated nearby, even if for the geologically short period of 170 years, cannot be ignored."
Whalin et al. (1970) have modeled the wave run-up which would occur at San Diego if a tsunami were to be generated locally. The period of the waves studied were intermediate, falling between values associated with the wind-wave and the typical tsunami-wave spectra; the longest studied was 186 seconds. Waves of this period are generated near tsu- nami sources, but become attenuated at great distance. They concluded that "the narrow, low-lying Silver Strand, the City of Coronado, California, and portions of North Island were completely inundated for most conditions tested. Wave heights in the restricted har- bor entrance approached 26 feet . . . bores were observed in the smaller partially enclosed basins, bays, and creeks surrounding the harbor."
LOCAL RISK REGIONALIZATION
Subdivision of earthquake risk into local regions depends on knowledge of local faults and on the response of the surficial geology to shaking.
Risk due to surficial and basement faulting.— Sur^cml faults in the San Diego area pre-
51
sent zones of increased risk due to the fact that the effects of shaking may be different on opposite sides of a fault. Where the fault zone itself is of considerable width, a third zone, possibly having a still different response, must be considered. Construction in zones of such variable response can result in earthquake-induced problems, such as differential settling, etc.
Figure 10 shows the faults in the San Diego area which are considered to be either "ac- tive" or "potentially active." The La Nacion fault has a verified length of approximately 15 miles. As this fault offsets Holocene materials at least locally and demonstrates repeated movement of late Pleistocene materials, it must be considered an active fault. The maxi- mum credible event that could be expected would be of magnitude 6.8 with expected acceleration approaching 0.4 g.
Determining the maximum credible surface breakage for basement faults deduced from gravity data is not a reliable method of estimating maximum credible earthquake magnitudes. The approximate locations and sense of movement of these faults (Fig. 1 1) do, however, provide clues to the thickness of the less competent overlying sediment, to the lo- cation of zones along which aftershocks remote to large events are apt to occur, and to the location of zones along which local earthquakes are more apt to be centered.
Response of surficial materials. —Seed (1969) stated that "analysis of the effects of soil conditions on damage due primarily to the effects of ground shaking requires an under- standing of the complex interrelationships between the effects of soil types, soil depth, the
a o
SURFACE OUTPUT
|
0 |
Hydraulic Fill Avg. BC= 21 (0=75%) |
|
|
9 |
^ Saturated Hydraulic Fill Avg. BC= 21 (D,= 6S%) "2=35 /j=95 /, = 120 |
|
|
13 20 |
Boy D*po>ilt Avg, BC = S (0,= 40%) Kj = 30 ^-^=82 J', = II3 |
|
|
3t |
T«r r ac« O«potit t Avg. BC=24 ( D,= 80%) K2=65 J'd = 102 /, = I26 |
|
|
San Di*go Formation Avg. BC = 59( D,= 90IOO%J '<2=" (|'d='05 ^".= 128 |
||
|
<fd~ "'V D«n«'«V |
||
|
^,= Wot D«n»ily |
||
|
D, = Rolaliv* D«n«ity |
||
|
1 ^ |
'. |
BC = Blow Count G= Kj(0)V2 |
|
300 |
fT - Ov«rburd«n Strsst |
BEDROCK IMPUT
Figure 20. Input acceleration, surficial geology, and resulting surface acceleration output (Equivalent damping
7.8%).
52
MISSION BAT
1857 Boundoiy Preieni Boundo
SAN DIEGO
CHUIA VISTA
Figure 21. Areas which have been filled since 1857. (Sources: U.S.G.S. Water Supply Paper 446; San Diego Bay, 1859 Coast Survey Office; San Diego Union, June 29, 1971).
amplitude of ground motions, the frequency characteristics of ground motions, and the structural characteristics of buildings in order to analyze damage resulting from past earth- quakes or prevent damage in future earthquakes."
From the standpoint of local zoning, a mappable parameter which reflects the max- imum expected shaking is desired. One approach, illustrated in Figure 19, is to calculate the maximum probable shaking at the bedrock-soil interface and compute the theoretical re- sponse expected at the surface of the ground (see Seed, 1969). From these data one can compile a series of maps which allow rough reconstruction of the maximum expected shak- ing for any particular period of shaking. Housner (1952) suggested that the area under the particle velocity spectrum over a range of shaking rates be used to define the local intensity of shaking. This measure of intensity would be obtainable directly from such maps.
To calculate the theoretical response at the ground surface, values of the shear modu- lus, unit weight, and damping factor are needed as a function of depth from the surface to bedrock. Care must be taken in selecting these values due to the nonlinearity of some of these "constants" with increasing strain. The seismic input should be either an average smoothed response compiled from earthquakes having magnitude and epicentral distance similar to the maximum probable event expected to affect the San Diego area, or a "white" input. An advantage of using a "white" input is that it allows separation of effects due to surficial materials from those due to the transmission path; it also provides a mappable out- put from which the response for any input is readily calculable.
We have carried out recently a similar analysis to determine the response of the sur- ficial materials to shaking and response of simple structures to the resultant velocity of sur- face shaking. Figure 20 shows the acceleration time history input at the top of the Cre- taceous sediments, the assumed geologic column overlying these sediments, and the theo- retically predicted acceleration time history which would result at the surface. For the geologic parameters and acceleration levels assumed, the maximum acceleration is in- creased by more than a factor of two (i.e. from 0.06 g to 0.13 g) in traversing the 300 foot column. Most of this amplification occurs in the upper 28 feet, which is assumed to be com- posed of loosely consolidated sediments. The stratagraphic column assumed is typical of much of the area surrounding the bays to which fill has been added (Fig. 21). These filled areas represent zones of maximum seismic risk.
The spectrum shown in Figure 22 approximates the particle velocity spectrum at the earth's surface for the conditions and assumptions described on Figure 20. If data of this
53
1.0 PERIOD-SECONDS
Figure 22. Spectral velocity derived from surface acceleration.
sort were available throughout areas of maximum expected seismic risk, considerable prog- ress could be made toward rational seismic-risk zoning.
CONCLUSIONS AND RECOMMENDATIONS
In this paper we have consolidated the background information developed by various experts in the field of geology, seismology, and earthquake engineering with specific appli- cation to the San Diego area, and have formed the following conclusions and recommenda- tions.
1. San Diego is in an active seismic area.
2. A Richter magnitude 7.3 earthquake on the Elsinore fault having a repeat interval of 60 years appears to be the "maximum probable" earthquake for San Diego. For most construction the "maximum probable" earthquake is recommended for design. In the case of structures such as hospitals which must remain operative during times of disaster and special installations such as nuclear reactors design should be based on the "maximum credible" earthquake.
3. Design studies should further consider the possible effects of a magnitude 7.8 "max- imum probable" earthquake on the San Jacinto fault because of its longer expected dura- tion of shaking.
4. Structures built on filled areas underlain by loose embayment type soils such as those found in San Diego and Mission bays are particularly susceptible to earthquake dam- age. Because of the numerous structures planned for such areas, a comprehensive study of the effects of earthquake-induced forces in embayment deposit areas is strongly recom- mended.
5. A seismic sea wave (tsunami) initiated within the offshore California Continental Borderland is possible. Such a wave could have a damaging eff'ect on low-lying shoreline areas along the Pacific Ocean and in mouths of bays.
ACKNOWLEDGMENTS
Publication of this paper has been made possible in part by financial support provided by the San Diego Asso- ciation of Geologists. This study was partially supported by a research grant from the Professional and Geotechni- cal Development Program of Woodward-Gizienski & Associates. This support is gratefully acknowledged.
We would like to thank L. J. Lee, S. P. Gizienski. and R. G. Gastil for reviewing this manuscript. R. P. Phillips for permission to publish his compilation of epicenters, and T. M. Gavin for his help with the computer analysis.
54
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1969. Seismic risk studies in the United States, p. 14-27. In, Proceedingsof fourth World conference on earth- quake engineering.
Allen, C. R.
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Allen, C. R., P. St. Amard. C. R. Richter, and J. M. Nordquist
1965. Relationship between seismicity and geologic structure in the southern California region. Seism. Soc. Amer. Bull. 55; 753-797
Allen. C. R.. L. T. Silver, and P. G. Stehh
I960. Agua Blanca fault— a major transverse structure of northern Baja California, Mexico. Geol. Soc. Amer. Bull. 71:457-482.
Artim. E. R., and C. J. Pinckney
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Buffington, E. C.
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Coffman, J. L., and W. K. Cloud
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Cluff. L. S.
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Elders, W. A., R. W. Rex, T. Meidav, and P. T. Robinson
1970. Crustal spreading in southern California. Institute of Geophvsics and Planetary Phvsics, U. California Riverside: 1-12 (pre-printed for private circulation prior to formal publication).
Elliott, W. J.
1970. Gravity survey and regional geology of the San Diego embayment, southwest San Diego County, Cali- fornia, p. 10-22. In. Amer. Assoc. Geol. Guidebook 1970 Fall Field Trip of Pac. Sec. of AAPG, SEPM, and SEG.
Elliott, W. J.
1964. Gravity survey of the southeast quarter of the San Diego quadrangle, California. Senior Thesis, San Diego State College.
Esteva, L.
1970. Seismic risk and seismic design decisions, p. 142-152. In. Seismic design nuclear power plants. M.I.T. Press. Cambridge. Mass.
Esteva. L.. and E. Rosenblueth
1964. Espectros de temblores a distancias moderadas y granelas. Soc. Mex. Ing. Sis. Bol. 2(1).
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1970. Study of regional seismicity and associated problems. Seism. Soc. Amer. Bull. 60: 393-446.
Gastil. R. G.. E. C. Allison, and R. P. Phillips
Reconnaissance geology of the State of Baja California. Geol. Soc. Amer. Mem. (in press).
Gutenberg, B.
1 94 1 . Mechanism of faulting in southern California indicated by seismograms. Seism. Soc. Amer. Bull. 3 1 : 263- 302. Gutenberg, B., and C. F. Richter
1954. Seismicity of the earth. Princeton L'niversity Press, Princeton, 2nd ed.: 310 p.
Housner. G. W.
1952. Intensity of ground motion during strong earthquake. California Inst. Tech., Earthquake Res. Lab., August 1952.
Housner, G. W.
1969. Engineering estimates of ground shaking and maximum earthquake magnitude, p. 1-13. In. Proceed- ings of fourth World conference on earthquake engineering.
55
lida, K.
1970. The generation of tsunamis and the local mechanism of earthquakes, p. 3-18. In, Tsunamis in the Paci- fic Ocean, Proceedings of the Int. Symp. on Tsunamis and Tsunami Research. East-West Center Press, Honolulu.
Joy, J. W.
1968. Tsunamis and their occurrence along the San Diego County coast. Westinghouse Ocean Research Lab report for the Unified San Diego County Civil Defense and Disaster Organization. 35 p.
Kennedy. M. P.
1969. Preliminary geologic map of a portion of northwestern San Diego City, California. California Div. Mines Geol. Open-File Rept.. Scale 1:9,600.
Linehan, D.
1970. Geological and seismological factors influencing the assessment of a seismic threat to nuclear reactors, p. 69-90. In. Seismic design for nuclear power plant. M.I.T. Press, Cambridge.
Moore, D. G.
1969. Reflection profiling studies of the California Continental Borderland: structure and Quaternary turbi- dite basins. Geol. Soc. Amer. Spec. Paper 107.
Peterson, G. L.
1970. Quaternary deformation patterns of the San Diego area, southwestern California, p. 120-126. In. Amer. Assoc. Geol. Guidebook 1970 Fall Field Trip of Pac. Sec. of AAPG. SEPM. and SEG.
Richter. C. F.
1958. Elementary seismology. W. H. Freeman and Company, San Francisco.
Richter, C. F.
1959. Seismic regionalization. Seism. Soc. Amer. Bull. 49: 123-162.
Savage, J. C, and R. D. Burford
1970. Accumulation of tectonic strain in California. Seism. Soc. Amer. Bull. 60: 1877-1896.
Scholz, D. H., and T. J. Fitch
1969. Strain accumulation along the San Andreas fault. J. Geophys. Res. 74: 6649-6666.
Schwiderski, E. W.
1968. Mantle convection and crustal tectonics inferred from a satellite's orbit: a diflferent view of sea-floor spreading. J. Geophys. Res. 73: 2828-2833.
Seed, B. H.
1969. The influence of local soil condition on earthquake damage. In. Soil dynamics. Proc. of specialty. Ses- sion 2. Seventh International Conference on Soil Mechanics and Foundation Engineering.
Seed, B. H., I. M. Idreiss, and F. W. Kiefer
1969. Characteristics of rock motions during earthquakes. Soil Mechanics and Foundations Division. Amer. Soc. Civil Eng. 95: 1199-1218.
Steinbrugge, C.
1966. Engineering seismicity aspects of Prince William Sound, Alaska earthquakes, preliminary report, March-April, 1964. U.S. Coast and Geodetic Survey: 58-75.
Von Hake. C. A., and W. K. Cloud
1966. United States earthquakes 1964. U.S. Coast and Geodetic Survey. Washington, D.C.
Whalen, R. W.. D. R. Bucci, and J. N. Strange
1970. A model studv of wave run-up at San Diego. California, p. 427-452. In. Tsunamis in the Pacific Ocean, Proceedings of the Int. Symp. on Tsunamis and Tsunami Research. East-West Center Press. Honolulu.
Wiegand. J. W.
1970. Evidence of a San Diego Bay-Tijuana fault. Assoc. Eng. Geol. Bull. 7: 107-121.
Department of Geology, San Diego State College, San Diego, California, and Wood- ward-Gizienski & Associates, San Diego, California.
56
APPENDIX Important Earthquakes, Modified and Up-dated from Joy (1967).
Type, Date, and Time z indicates GMT * indicates PST
Generating region and epicenter, if known. Magnitude (Arabic) Modified Mercaili Intensity (Roman)
Remarks and References
Local earthquake April II, 1769
Coastal earthquake November 22, 1800, 1330*
Local earthquake May 25, 1803 (no tsunami noted) Regional earthquakes May, 1812
Local earthquakes October 12, 1812 Coastal earthquake December 8, 1812 about 0700*
Local earthquake June 23, 1843, 1530* Local earthquake September 16, 1849 Local earthquake September 22, 1849 Local earthquake April 12, 1852 Local earthquakes October 26, 1852 November 27-30, 1852 (no tsunami noted) Possible remote tsunami November 1853
Remote tsunami
December 23, 1854,
0015Z
December 24, 1854,
0800z
Local earthquake
September 20, 1856
Several local earthquakes May 27, June 13-14, 1862 October 21, 1862 January 25, 1863, 0200* July 7, 1963, 1311* Local earthquake April 19, 1865 Remote tsunami April 2, 1868
San Diego (severe)
Southern Cahfornia (VII)
San Diego, near 32.5°N 117°W
Southern California
San Diego
Coastal Southern Cali- fornia (VIII-IX)
San Diego (very severe) Baja California Santa Ysabel San Diego County Carrizo Creek San Diego County San Diego
San Diego (IX-November 29, 1852)
Kuril Islands
Ansei, Tokkaido, Japan 34.1°N; 137.8°E(8.4)
33.2°N; 135.6°E(8.4)
San Diego County (VII)
All at San Diego
San Diego S. E. Hawaii
Diary of Miguel Costanso, Portola Expedition 1769-1770. Bancroft (Works, VoL 18, p. 127); Wood (1916); Townley & Allen (1939). The adobe walls of San Diego Presidio barracks were cracked. California Archives Provincial State Papers XXI, p. 135; HitteU (1898); Wood & Heck (1966); Trask (1864); Bancroft (1883) p. 86, 654,658.
Slightly Damaged San Diego Mission Church, Wood & Heck (1961); Bancroft (1883) p. 106, 114; Wood (1916).
Southern California was subjected to nearly continuous shocks for 4 Vi months. The inhabi- tants abandoned their houses and lived out of doors. Townley & Allen (1939). Shocks for 40 days. Townley & Allen (1939).
Mission San Juan Capistrano destroyed. Strongly
felt at San Diego, but no damage to San Diego
Mission. Probably on Inglewood-Newport fault.
Bancroft (1883) p. 347-348; Lounderback (1948);
Heizer (1941) p. 221; 5. F. Bulletin, March 5,
1864, March 19, 1864, p. 3, c. 4.
Southern California to Mexico. Townley &
AUen (1939); Wood & Heck (1966).
Probably on the Elsinore fault. Townley &Allen
(1939).
Probably on Elsinore fault. Townley & Allen
(1939).
Townley & Allen (1939).
November 29 two minute shock in San Diego followed by light quakes for several days. Trask (1856); Wood, (1916); Townley & Allen (1939).
Reported to be a large tsunami. Small waves possibly recorded on newly installed San Diego gage. Solov'ev and Ferchev (1961); lida, et al., (1967); U.S. Coast Survey Report for 1855 (1856) p. 99.
A very large tsunami. Recorded at San Diego + 12.6 hrs. later, 0.5 feet, 31 min. avg. period. Bache (1856); lida, et al, (1967); Shuck (1869). Two tsunamis, whose effects along this coast were more or less merged together. Walls cracked, ceilings fell, and local Indians were terrified. Cattle stampeded at Santa Ysabel. Wood & Heck (Rev. 1966). May 27, severe shock at San Diego, Temecula, Probably on Elsinore fault. Track (1864); Bancroft, MMs cited by Townley & Allen (1939).
Severe shock. Townley & Allen (1939).
Recorded at San Diego, 0.33 ft; 30 min. avg. period. S. F. Bulletin, June 13, 1868; lida, etai, (1967); Heck (1947); Townley & Allen (1939).
57
Type, Date, and Time z indicates GMT * indicates PST
Generating region and epicenter, if known. Magnitude (Arabic) Modified Mercalii Intensity (Roman)
Remarks and References
Remote Tsunami August 13, 1868, 1645Z
N. Chile; So. Peru 18.5°S;71°W
Remote Tsunami August 23, 1872
Remote tsunami September 16-17, 1872
Hawaii (?)
(?)
Remote tsunami
November 22, 1878
Probably either that of
May 10, 1877, or August
13, 1868, but misdated.
(no local earthquakes reported)
Offshore or coastal earthquake Los Angeles region
earthquakes and possible (VI-V)
local tsunami August 10,
1879, 1315*
Local earthquakes
December 21, 1880
2300*
Local earthquakes
March 11, 1882, 1600*
March 30, 1882, 2300*
Octobers, 1882,0200*
(no tsunamis)
Local inland earthquake
February 9, 1890,0406*
(no tsunami)
Offshore earthquakes
February 23, 1892, 2320*
Several aftershocks
(no tsunamis)
Local earthquake
October 23, 1894
Local earthquake
July 3, 1896,2127*
(no tsunami)
Local inland earthquake
December 23, 1899,0425*
Remote tsunami
January 31, 1906, 1536z
San Diego (V-strongest)
San Diego (Ill-V)
San Jacinto fault (VI)
Off coast N.W. of Ensenada, B.C., Mexico 31.5°N; 116.5°W(VII-1X)
San Diego-Poway region 33°N; 117°W(V1I) San Diego (Small)
San Jacinto fault
(IX)
Columbia - Ecuador
1°N; 81.5% (8.6)
Great Africa, Peru, Tsunami. Recorded at San Diego 1 1.9 hrs. later, 1.0 ft, 16 min. avg. period. Noted at San Pedro and Wilmington, 6.0 ft, 20 min. avg. period. Proctor's article gives heights at San Pedro which are 10 times too great ac- cording to local newspaper accounts. Alta Cali- fornia, September 12, 1868;Z,./4. Star, August 14-19, 1868; lida, era/., (1967); von Hockstetter (1868); (1869); Berninghausen (1962); Proctor (1869).
lida, et at., (1967), lists a tsunami noted in Hawaii on this date. Davidson (1872) gives August 24th as the date that a tsunami was ob- served at Astoria, San Diego, and San Francisco. No details.
Davidson (1872) states that tsunami activity was noted on these two dates on the San Diego, San Francisco, and Astoria Ore. tide gages. No de- tails or confirmation from other sources. Angel (1883) reports 6 ft. waves at Wilmington. Waves and damage done at San Luis Obispo, Point Sal, Avila, Port Harford, Surf, Pismo, Morro Bay, and Cayucos. Not noticed in San Diego. No reports from any other source for tsunamis of this date.
Sea wave noted in Santa Monica Bay. Not report- ed in San Diego. The sea wave was originally reported by Rockwood who was cited by Townley & Allen; no detail, small earthquake. No tsunami noticed elsewhere. lida, et ai, (1967) cite Wood (1916) as authority for this event and accept it as a valid tsunami. Rockwood (1879); Wood (1916); Townley & AUen (1939); lida, era/., (1967). Townley & AUen (1939); Rockwood (1881).
Townley & AUen (1939).
Felt in San Diego. Wood & Heck (Rev. 1966).
Considerable datnage in San Diego. Possibly Aqua Blanca fault. Wood & Heck (1966); Richter (1965); Holden (1898); Allen, Silver, & StehU (1960); Townley & AUen (1934). Walls cracked, but no serious damage in San Diego. Wood & Heck (1966). Townley & AUen (1939).
Felt in San Diego. Wood & Heck (Rev. 1966).
A major tsunami; said to have been recorded in San Diego although heights not given. Heck (1947); lida, era/., (1967).
58
Type, Date, and Time z indicates GMT * indicates PST
Generating region and epicenter, if known. Magnitude (Arabic) Modified Mercalli Intensity (Roman)
Remarks and References
Local inland earthquake May 15, 1910,0747* (no tsunami) Remote tsunami November 10, 1922 0433z
Remote tsunami February 4, 1923 1602z
Remote tsunami April 14, 1923, 1531Z
Offshore earthquakes and local tsunami November 4, 1927, 1351z 0551*
Remote Tsunami March 3, 1933 March 2, 1933, 17:31z October 2, 1933, Aftershock
Coastal earthquake March 10, 1933 1754*
Local inland earthquake December 30-31, 1934
Large local earthquake May 18, 1940, 2036* ( no tsunami)
Possible remote tsunami February 9, 1941, 0144*
Lake Elsinore (6.0)
Atacama, No. Chile 25.5°S; 70°W (8.3)
Kamchatka 54°N; 161°E(8.3)
Kamchatka 56.5°N;162.5°E(7.2)
Off Cape Arguello 34.5°N;121.5°W (7.3, IX-X)
Sanriku, Japan Tuscarora Deep 39.l'^N;144.7^E
Long Beach, California 33.6^N; 118°W(6.25,IX)
Imperial Valley in Mexico 32°N; 114.75^W(7.1,IX, X)
S.E. of El Centro 32.7°N; 115.5°W(7.1,X)
Cape Mendocino, California 40.9°N;125.4°W(6.6)
Felt in San Diego. Probably Elsinore fault. Wood & Heck (1966).
At San Diego 13 hrs. later, 1.3 ft. max., 15 min. period. Willis, (1929); Berninghausen (1963); lidai, etal., (1967).
At San Diego 10 hrs. later, 1.3 ft. max., 10 min. period, lida, etal., (1967); Miller (1964) RED in Honolulu.
At San Diego 14.3 hrs. later, 0.75 ft. max., 43 min. period, lida, etal., (1967); MiUer (1964) RED in Honolulu.
This is the only well documented locally gener- ated tsunami in California history. Byerly's paper reproduces marigrams. This was a very small tsunami; very small at La Jolla and San Diego, but was detected at Hilo, Hawaii 5.1 hrs. later where it produced water level excursions of about 8 in. Along this coast the max. heights nowhere exceed those attained by great tsunamis of distant origin. According to Wilson the earth- quake was felt at sea by the S.S. Socony which at the time was at 34°54'34"N; 121°01'00"W. La JoUa +0.9 hrs., 0.02 ft. (6mm)
Nr. Port San Luis 5 ft.
Surf-Pismo 6 ft.
San Diego 0.02 ft.
San Francisco +1.2 hrs., 0.02 ft. (4mm)
(15 min. period at La Jolla, 12 min. period at San Francisco) Byerly (1930); Wilson (1928); Miller (1964) RED; Wood & Heck (1961); lida, etal., (1967); Cox (1964). Great Sanriku Tsunami.
Santa Monica 0.35 ft.
San Pedro +11.5 hrs. 0.75 ft.
La JoUa 0.25 ft.
San Diego - probably recorded but very small. (14 min. period at San Pedro, 1 1 min. period at La JoUa). Neumann (1935) Heck (1947); lida, etal., (1967); Miller (1964) BLUE in Hawaiian Island.
Destructive Long Beach earthquake. Newport- Inglewood fault. Tide gage records ground motion at Long Beach. Nothing noticed on San Diego tide gage record. Slight activity no- ticed at La Jolla; possible shelf seiche. The earthquake was felt aboard ships. Aftershock felt in San Diego. Emery (1960) p. 125; Wood (1933); Bittinger (1933); Wood & Heck (1961); Eaton (1933); Clements & Emery (1947); Buwalda(1933).
Strongly felt in Tiajuana and San Diego. Also felt in Arizona and Nevada. Wood & Heck (1966).
The surface rupture produced during this earth- quake was over 40 miles long. Shocks strongly felt throughout San Diego County with some damage. Wood & Heck (1966). From inspection of local tide records; not re- ported elsewhere. San Diego: +14 hrs., general increase in harbor seiching. La Jolla: no unusual activity noticed. Port Hueneme: +36 hrs., general increase in harbor seiching. San Fran- cisco: + 14 hrs.. some harbor seichine.
59
Type, Date, and Time z indicates GMT * indicates PST
Generating region and epicenter, if known. Magnitude (Arabic) Modified Mercalli Intensity (Roman)
Remarks and References
Remote tsunami December 7, 1944, 0435z
Local earthquake January 1, 1946,
Remote Tsunami April 1, 1946, 1229*
Kii, Japan
33.75^N; 136°E (8.0)
32°43'N;117°25'W(3.3)
Aleutian Islands 53.5°N; 163^(7.4)
Local inland earthquake Anza Desert
September 5, 1950, 1120* 33.7'^N; 116.8°W (4.8) (no tsunami)
Offshore earthquake San Clemente Island
December 25, 1951, 1647* 32.8°N; 118.3°W (5.9, VI)
Remote tsunami March 4, 1952
Hokkaido, Japan 42.2°N; 143.8°E (8.1)
Remote tsunami Kamchatka
November 5, 1952, 1658z 57.75°N; 159.5°E (8.25)
Local inland earthquake June 13, 1953,2017* Local earthquake March 19, 1954, 0154*
Local inland earthquake March 22, 1954, 2015* Local inland earthquake October 17, 1954, 1457*
Local inland earthquake October 24,1954,0144*
Local inland earthquake November 12, 1954, 0427* Two aftershocks Local earthquakes January 3, 1956 February 9, 1956, 0633*
Local earthquakes February 14, 1956, 1033* 1720*
Imperial Valley 32.8°N; 115.7°W(VII)
Borrego Springs 33°17'N; 116^11'
W(VI)
Santa Rosa Mountains 33.3°N; 116.2°W(5.1,VI) Baja California 31.5°N;116.5°W(5.7)
Baja California 31.5°N;116°W(6.0)
Baja California 31.5°N;116°W(6.3)
Baja California
bothat31.8°N; 115.9°W
1/3/56 (4.7)
2/9/56 (6.8, VI-VIII)
Baja California
31.8°N; 115.9°W(V-VIII)
1033* = 6.3
1 T^n* - C A
San Diego La Jolla Los Angeles Port Hueneme San Luis Obispo Avila, Calif.
San Diego, +13.9 hrs., 0.33 ft., 14 min. period. Terminal Island, Long Beach, 0.33 ft., 16 min. period. lida, etal, (1967); Heck (1947); Bodle(1946).
Locahzed shock in the coastal area running from La Jolla through San Diego and National City "Buildings swayed." A great tsunami
1.3 ft. +6.2 hrs. 1.4 ft.
2.6 ft.
5.5 ft. +5.6 hrs., 8.0 ft.
3.8 ft.
Munk (1953); Green (1946); Bodle & Murphy (1948); lida, e/fl/., (1967); MiUer (1964) BLUE. Felt in San Diego. Wood & Heck (1966).
Slight damage in San Diego and northern parts of the county. No tsunami. Richter (1965); Wood & Heck (1966). "There is some coherence between the two records, with similar phases occurring at Ocean- side 2 to 3 min. after La Jolla." (Munk, 1953). Los Angeles, 2.6 ft: Oceanside, 1.5 in.; La Jolla, 1.0 in. (10 min. avg. period at Oceanside and La JoUa). Munk (1953); Miller (1964) RED; Murphy & Cloud (1954); lida, etal, (1967). A great tsunami. San Diego La Jolla
L.A. (Berth 174) San Pedro Bkwtr Santa Monica Port Hueneme Avila, Calif.
lida, et al., (1967); Zerbe (1953); MUler (1964) RED.
Felt from San Diego to Phoenix, Arizona. Wood & Heck (1966).
Intensity VI at La Jolla. Felt by and awakened many in La Jolla; frightened few. Cracked plastt and a few walls in La Jolla. Murphy & Cloud (1956).
Slight damage from Palm Springs to San Diego, Wood & Heck (1966). Felt in San Diego County, Probably Agua Blanca fault. Murphy and Cloud (1956) Richter (1958).
Felt in San Diego County. Probably Agua Blanca fault. Murphy and Cloud (1956); Richter (1958).
Extensive damage at El Alamo, Mexico. Felt in San Diego and much of southern California. Wood & Heck (1966).
Tecate, B.C., Mexico to San Diego. Probably San Miguel fault. Richter (1965); Wood & Heck (1961).
|
San Diego |
+9.6 hrs. |
2.3 ft. |
|
La Jolla |
+9.6 hrs. |
0.8 ft. |
|
L.A. (Berth 174) |
+9.6 hrs. |
2.3 ft. |
|
San Pedro Bkwtr. |
+9.5 hrs. |
1.7 ft. |
|
Santa Monica |
+9.6 hrs. |
4.7 ft. |
|
Port Hueneme |
+9.0 hrs. |
2.3 ft. |
|
Avila, Calif. |
+9.0 hrs. |
3.3 ft. |
Probably on San Miguel fault. Wood & Heck (1961).
Richter (1965);
60
|
Type, Date, and Time z indicates GMT * indicates PST |
Generating region and epicenter, if known. Magnitude (Arabic) Modified Mercalli Intensity (Roman) |
Remarks and References |
Remote tsunami March 9, 1957, 1422*
L.A. Harbor Berth
Remote tsunami May 22, 1960, 1911z
Remote tsunami March 27, 1964, 0336z
Offshore earthquake December 22, 1964 (No tsunami noted)
|
Aleutian Islands |
A great tsunami. |
|
|
51.3 N;175.8°W (8.0-8.5) |
Ensenada, B.C. |
|
|
Mexico |
+6.8 hrs. 3.4 ft. |
|
|
San Diego |
+6.9 hrs. 1.5 ft. |
|
|
La JoUa |
+6.6 hrs. 2.0 ft. |
|
|
Newport Bay |
+6.6 hrs. 0.9 ft. |
|
|
Anaheim Landing |
+6.7 hrs. 2.6 ft. |
|
|
Long Beach |
+6.6 hrs. 1.7 ft. |
|
|
San Pedro Bkwtr |
+6.6 hrs. 1.2 ft. |
|
|
L.A. Harbor Term.I +6.6 hrs. 0.6 ft. |
||
|
L.A. Harbor |
||
|
Berth 60 |
+7.0 hrs. 2.1 ft. |
|
|
L.A. Harbor Berth |
||
|
174 |
+6.9 hrs. 3.1 ft. |
|
|
Santa Monica |
+6.6 hrs. 3.0 ft. |
|
|
Port Hueneme |
+6.5 hrs. 3.5 ft. |
|
|
Avila, Calif. |
+5.8 hrs. 3.5 ft. |
|
|
lida, era/., (1967); |
Salsman(1959);MiUer |
|
|
(1964) BLUE. |
||
|
Southern Chile |
A great tsunami. |
|
|
41.0°S;73.5"W |
Ensenada, B.C. |
|
|
(8.25-8.5) |
Mexico |
+ 13.6 hrs. 8.1 ft. |
|
San Diego |
+ 14 hrs. 4.6 ft. |
|
|
La JoUa |
+ 14 hrs. 3.3 ft. |
|
|
Wilson Cove, |
||
|
San Clemente |
||
|
Island |
+ 14 hrs. 4.1ft. |
|
|
Alamitos Bay, |
||
|
Long Beach |
+ 14.5 hrs. 4.0 ft. |
|
|
L.B. Naval Ship |
||
|
Yard |
+ 14.4 hrs. 5.7 ft. |
|
|
San Pedro Bkwtr. |
+ 14.5 hrs. 3.0 ft. |
|
|
L.A. Harbor Berth |
||
|
60 |
+ 14.5 hrs. 5.0 ft. |
|
|
Santa Monica |
+ 14.4 hrs. 9.1 ft. |
|
|
Port Hueneme |
+ 14.3 hrs. 8.8 ft. |
|
|
Berkman & Symons (1964); lida, etai, (1967); |
||
|
Miller (1964) RED, |
||
|
Prince William Sound |
Great Alaska Earthquake and Tsunami. |
|
|
&GuIf of Alaska (8.4) |
Ensenada, B.C. |
|
|
Mexico |
+6.1 hrs. 7.8 ft.+ |
|
|
San Diego |
+6.2 hrs. 3.7 ft. |
|
|
La JoUa |
+5.8 hrs. 2.2 ft. |
|
|
Newport Bay |
+5.8 hrs. 1.3 ft. |
|
|
Alamitos Bay, |
||
|
Long Beach |
+5.9 hrs. 2.8 ft. |
|
|
L.A. Harbor Berth |
||
|
60 |
+5.8 hrs. 0.4 ft. |
|
|
Santa Monica |
+5.7 hrs. 2.5 ft. |
|
|
Avila, Calif. |
+5.4 hrs. 5.0 ft. |
N.W. of Ensenada, B.C. Mexico; 31.9°N; 117.1°W(5.5)
Spaeth & Berkman (1965); lida, era/., (1967). Possibly on submerged portion of Agua Blanca fault. Richter (1965).
Remote tsunami October 17, 1966 Local inland earthquake April 8, 1968, 1828*
Local inland earthquake April 28, 1969, 1521*
Near coast of Peru 10.7^S;78.7°W(7.5) Ocotillo Wells, Calif. 33°10.5'N; 1 16^^07. 3'W (6.5, VII)
Borrego Springs, C 33.°21'N; 116^21' (5.9, VII)
s, Calif. W
San Diego, +10.1 hrs., 0.25 ft. Berkman & Carrier (1967); lida, e/ a/., (1967). Felt by and frightened all in San Diego. In- tensity VI in San Diego. Cracks opened on the west side of Sunset CUffs Boulevard. Plaster cracked and fell in several San Diego buildings. A 9 ft. concrete retaining wall had 1/8-in. crack from top to bottom, von Hake & Cloud (1970). Intensity V in San Diego.
61
APPENDIX REFERENCES
Allen. C. R.. L. T. Silver, and F. G. Stehli
1960. Agua Blanca Fault-a major transverse structure of northern Baja California. Mexico Geo! Soc Amer. Bull. 71:457-482.
Angel. M.
1882. The history of San Luis Obispo County. Publisher unknown, p. 329-330. (available Los Angeles Main Public Library).
Bache. A. D.
1856. Report of Superintendent of the United States Coast Survey for 1855. Notice of earthquake wave on the western coast of the U.S. on the 23rd and 25th of December, 1854. Washington. D.C.. p. 99; Appen- dix 50, 342-346. (also published in Amer. J. Sci.. Series H. 21(61): 37-45).
Bancroft. H. H.
1883. History of California. A. L. Bancroft. San Francisco 2: 201, 263. 268. 346-358. 363-368.
Berkman. S. C. and D. C. Carrier
1967. The tsunami of October 17. 1966 as recorded by tide gauges. Coast and Geodetic Survey ms., 5 p. (on file in International Tsunami Information Center. U. Hawaii, Honolulu).
Berman. S. C. and J. M. Svmons
1964. The tsunami of May 22. 1960 as recorded at tide stations, U.S. Dept. Comm., Coast and Geodetic Sur- vey. Washington. D.C.. 79 p.
Berninghausen. W. J.
1962. Tsunamis reported from the west coast of South America. 1562-1960. Seism. Soc. Amer. Bull. 52(4): 915-921.
Bittinger. C.
1933. Experiences over a submarine epicenter. Amer. Geophys. Union. Trans 14th Ann. Mtg., p. 260. (also in Earthquake notes. Seism. Soc. Amer. (Eastern Section) June 5(1&2), p. 260).
Bodle, R. R.. and L. M. Murphy
1948. U.S. earthquakes, 1946. U.S. Dept. Comm.. Coast and Geodetic Survey, Washington, D.C., Ser. 715. 45 p.
Buwalda. J. P.
1933. The Long Beach earthquake— what happened geologically. Sci. 70(2016): 148-149.
Byerly. P.
l"930. The California earthquake of November 4. 1972. Seism. Soc. Amer. Bull. 20(2): 53-66.
Clements. T.. and K. O. Emery
1947. Seismic activity and topography of the sea floor off southern California. Seism. Soc. Amer. Bull. 37(4): 309-313.
Cox. D. C.
1964. Unpublished list of tsunamis, p. 96. In Weigel, Oceanographic engineering. Prentice-Hall.
Davidson, G.
1872. Remarks on recent earthquake waves. California Acad. Sci., Proc. 4(5): 268.
Eaton. J. E.
1933. Long Beach. California earthquake of March 10. 1933. Amer. Assoc. Pet. Geol. Bull. 17: 732-738.
Emery. K. O.
1960. The sea off southern California. John Wiley and Sons, New York.
Green. C. K.
1946. Seismicsea wave of April 1. 1946 as recorded on tide gauges. Amer. Geophvs. Union. Trans. 27(4): 490- 500.
Heck. N. H.
1947. List of seismic sea waves. Seism. Soc. Amer. Bull. 37(4): 269-284.
Heizer, R. F.
1941. California earthquakes of the mission period. 1769-1838, p. 219-223. California. J. Mines Geol., Rep. No. 34 of the state mineralogist, April 1941.
Hittell. T. H.
1898. History of California. N. J. Stone and Co.. San Francisco. 2: 547 p.
Holden. E. S.
1898. A catalog of earthquakes of the Pacific coast from 1769-1897. Smithsonian Misc. Coll.. Washington. D.C.. No. 1087.
lida. K.. D. C. Cox. and F. Parares-Caravannis
1967. Preliminary catalog of tsunamis occurring in the Pacific Ocean. Hawaii Inst. Geophys., Rep. HIG-67- 25, U. Hawaii.
Louderback. G. D.
1948. California earthquakes in 1812. Paper presented April 9. 1948, Seism. Soc. Amer. Ann. Mtg. (Abstract: Geol. Soc. Amer. Bull.. 59(12). part 2. December 1948).
62
Miller, G. R.
1964. Tsunamis and tides. PhD. Thesis. Univ. Calif., Scripps Inst. Oceanogr., 120 p.
Munk. W. H.
1953. Small tsunami reaching California from the Japanese earthquake of March 4, 1952. Seism. Soc. Amer. Bull. 43(3): 219-222.
Murphy, L., and W. Cloud
1954. U.S. earthquakes, 1952. U.S. Dept. Comm., Coast and Geodetic Survey, Washington, D.C., ser. 773.
Murphy, L., and W. Cloud
1956. U.S. earthquakes, 1954. U.S. Dept. Comm., Coast and Geodetic Survey, Washington, D.C.. ser. 793.
Neumann, F.
1935. U.S. earthquakes, 1933. U.S. Dept. Comm., Coast and Geodetic Survey, Washington, D.C., ser. 579.
Proctor, R. A.
1869. Earthquake waves in the Pacific. Nature 1: 54-56.
Rockwood, C. G.
1879. Notes on American earthquakes. Amer. J. Sci.. 3rd series, vols, for 1872-87.
Salsman, G. G.
1959. The tsunami of March 9, 1957 as observed at tide stations. U.S. Dept. Comm., Coast and Geodetic Survey, Washington, D.C., Tech. Bull. 6, 18 p.
Shuck, O. T.
1869. Cahfornia scrap-book; a repository of useful information and select readings, p. 246, 274, 298, 386, 476. H. H. Bancroft and Co., San Francisco and New York.
Spaeth. M. G., and S. C. Berkman
1967. The tsunami of March 28, 1964 as recorded at tide stations. U.S. Dept. Comm., Coast and Geodetic Survey, Washington, D.C., No. 33, 86 p.
Townley, S. D., and M. W. Allen
1939. Descriptive catalog of earthquakes of the Pacific coast of the United States 1769-1928. Seism. Soc. Amer. Bull. 29(1): 1-297.
Trask, J. B.
1856. Untitled paper of earthquakes in California from 1812 to 1855, p. 84-86. California Acad. Nat. Sci., Proc. 1 (January 14, 1856).
Trask, J. B.
1864. Earthquakes in California from 1800 to 1864, p. 130-153. California Acad. Nat. Sci., Proc. 3 (April 18, 1864).
von Hockstetter, F.
1868. On the earthquake in Peru on 13 August 1868 and the flood wave caused by it in the Pacific Ocean, particularly on the coasts of Chile and New Zealand (in German). Sitzungsher, d.k. Akad. d. Wiss- ensch., Vienna, 59, p. 109.
SAl\J
(0(0% LIBRARY ■
Dlu 7 1^7^
i'
J HARVARO
t\\ UNIVERSITY
THE FEEDING TECHNIQUES
OF STILT SANDPIPERS AND DOWITCHERS
P.J. K. BURTON
TRANSACTIONS
OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
VOL. 17, NO. 5 16 AUGUST 1972
THE FEEDING TECHNIQUES
OF STILT SANDPIPERS AND DOWITCHERS
P. J. K. BURTON
ABSTRACT.— This paper presents descriptive and quantitative observations of feeding behavior of Stih Sandpipers (Micropalama himantopus) and dowitchers (Limnodromus spp.). Stilt Sandpipers make frequent use of "stitching" -a series of extremely rapid jabs into the mud surface, performed while pivoting the body or walking. This is probably a means of tactile foraging; visual searching behavior is also used. Dowitchers do not "stitch" but employ isolated (though frequent) deep jabs and probes, which are often prolonged and vig- orous. They show little evidence of hunting by sight. The differences provide further evidence for assigning the Stilt Sandpiper and dowitchers to the Calidridinae and Scolopacinae, respectively. Significant differences in anatomy of the feeding apparatus are summarized.
The great diversity in bill shape and size among shorebirds leads one to expect a corre- sponding diversity in feeding techniques and methods; yet there have been few really de- tailed and quantitative studies of these techniques. One of the most thorough, concerning European shorebirds, is a little known study by Streefkerk (1960). Detailed descriptions of feeding methods in five species of shorebirds, with a summary of information available for others, are given by Burton (1969, and in press). The present paper concerns dowitchers {Limnodromus spp.) and the Stilt Sandpiper {Micropalama himantopus). Various descrip- tions in the literature suggest a close similarity between the feeding methods of these birds, and both are often stated to employ a "sewing-machine action" (e.g., by Peterson, 1947). The best accounts are those of Bent (1927) and Palmer (1967), but these include observa- tions from a variety of sources and are insufficiently detailed for comparative purposes.
Dowitchers and Stilt Sandpipers have often been considered closely related, as in- dicated by their juxtaposition in many North American lists until recently. According to an alternative view (Lowe, 1931; Peters, 1934) the Stilt Sandpiper is closely related to Calidris (Scolopacidae, subfamily Cahdridinae), while dowitchers are allied to the snipes, Gallinago spp. (subfamily Scolopacinae). This view is reinforced by recent work (Jehl, 1968; Burton, in press). As the Calidridinae and Scolopacinae differ extensively in feeding methods, the alleged similarity in this respect between dowitchers and the Stilt Sandpiper is surprising. Therefore, during the course of a visit to Texas during the latter half of April, 1969, I took the opportunity to make detailed observations on their feeding behavior.
METHODS
Stilt Sandpipers were watched principally at a brackish pool lying between agricultural land and mesquite brush near Alamo, lower Rio Grande valley, Texas. Dowitchers (mostly L. griseus)weTe watched at tidal pools on the mudflats of the west (Laguna Atascosa) shore of Padre Island, near Port Isabel, Texas. Observation was by telescope (30 X to 60 x). Quantitative aspects were studied by dictating running commentaries into a portable tape recorder. This provided data amenable to statistical treatment, and to timing of various items; some timed data were also obtained in the field, using a stop watch. Prolonged exam- ination of qualitative aspects of behavior were also made, in addition to the taped recorded commentaries. The total observation time (about 20 hours for each species) is relatively brief but served to clarify considerably the similarities and diff'erences between the two spe- cies in feeding methods.
STILT SANDPIPER
Three principal types of feeding action were distinguished: a. Pecks.— These are extremely brief movements made into water, or at its surface, or
SAN DIEGO SOC. NAT. HIST., TRANS. 17 (5): 63-68, 16 AUGUST 1972
64
into the surface of exposed mud.
b. Probes.— LongeT movements in which the bill is thrust into the mud for some depth. As in the case of Dunlin {Calidris alpina) studied by Burton (in press), these are normally made with a very rapid up-and-down quivering action. This, and their distinctly longer duration, are the only means of distinguishing them from pecks when (as fre- quently happens) the insertion of the bill into the mud cannot be seen.
c. Stitching.— This term is used by Burton (in press) to refer to a feeding action which appears to be characteristic of the Calidridinae. It has previously been described from several members of the subfamily by Streefkerk (1960), Holmes (1966), and others. Basically, stitching consists of very rapid series of shallow jabs into the mud surface, made while on the move; Holmes (1966) refers to it simply as a "rapid series of jabs." Stitching and probes may appear closely similar, and in fact intergrade; probes are generally made in one spot, and usually deeper and more vigorously than stitching.
The Stilt Sandpipers invariably fed on mud covered by a layer of water, sometimes barely covering the feet, but usually to about tarsus length, and commonly to belly depth. A notable characteristic mentioned by several authors is their lack of mobility. This is espe- cially striking by comparison with other species feeding near them in similar situations, in this case Lesser Yellowlegs {Tringa flavipes) and Wilson's Phalarope {Phalaropus tricolor). This lack of mobility is also a contrast to most other members of the Cahdridinae, which, however, generally feed in shallower water or on exposed substrates.
Several accounts of the habits of the Stilt Sandpiper mentioned a characteristic atti- tude, with neck outstretched and bill pointed vertically down. This attitude is indeed well marked in this species, though a similar attitude is quite often assumed by other shorebirds (e.g. Redshank, Tringa totanus)vj2iding in fairly deep water. It is restricted to spells of feed- ing by means of pecks; stitching series are carried out with the bill inclined at about 80° to the horizontal, as in other Calidridinae. The more perpendicular bill carriage where pecks predominate is probably related to the fact that these are used in hunting by sight; the per- pendicular attitude may serve to minimize errors due to refraction. Stitching, on the other hand, appears to be a form of trial probing with the object of detecting prey by tactile means. The behavior of the birds while making pecks gave a strong impression that they were engaged in visual search. They would walk slowly about, on a zig-zag path or back- wards and forwards, not covering a great amount of ground, but maintaining the out- stretched neck and perpendicular attitude throughout.
Stitching usually involves even less mobility, and one bird may spend an hour or more in an area only a yard or so across; similar lethargy mentioned by Bent (1927) and Palmer ( 1967) probably refers to birds feeding in this way. By contrast with most Calidris species, which usually stitch while walking, Stilt Sandpipers generally carry this out while standing still, the only movement usually being a side to side pivoting at the pelvis combined with neck action, so that the stitching jabs are made around it in a semicircle. The tracks left by this process should have been highly characteristic if there were any, but the mud surface was much too soft to retain indentations. The bird seen swinging its immersed bill from side to side mentioned by Bent and Palmer was very probably stitching. Palmer's comparison with a side to side action seen in the Greater Yellowlegs (Tringa melanoleuca) is probably misleading. A side to side action is shown by a variety of Tringinae, especially Redshank (T. totanus) and Willet (Catopfrophorus semipalmatus), but close examination shows it to be accompanied by very rapid opening and shutting jaw movements, a feature never seen in the stitching of Calidridinae which it superficially resembles.
Stitching was usually performed in more shallow water than feeding by pecks, though some prolonged spells of stitching took place with the head completely immersed, only the quivering and slow pivoting of the body indicating what was happening. On the rare occa- sions when stitching was carried out on virtually exposed mud, it could be seen that the bill was very slightly open at the tip, as in Dunlin. The duration of 321 stitching sequences timed gave a mean of 2.3 sees with a maximum of 13.7 sees. This is somewhat shorter than that recorded for Dunlin (mean 3.9, maximum 25.7) on a tidal mudflat by Burton (in press) though it is pointless to pursue the comparison too closely.
Probes were relatively brief, the great majority lasting under one second. Since most
65
were made under water (usually of belly depth), the depth to which the bill was inserted into the mud could not normally be seen; when visible, the amount of insertion appeared not less than half the bill length, and frequently its full length. No changes of bill orien- tation were seen during the course of a probe. The great majority of probes were isolated, but up to six have been observed in one spot, presumably in efforts to capture a particularly difficult prey animal. Most obvious captures (indicated by head jerking and swallowing movements) followed probes rather than pecks; probably the items acquired by pecking were mostly so small that their capture went unobserved.
The proportions of pecks, probes and stitching sequences in 52 minutes of timed obser- vations were recorded (Table 1). Each stitching sequence was counted as a single move- ment. The mean number of feeding movements per minute was 40.2 (min. 10, max. 82). High rates were associated with a large proportion of pecks— not surprisingly, since pecks are the most rapid movements. Conversely, low rates are associated with a high proportion of spells of stitching, which are of longer duration than pecks or probes. Interestingly, high- est probing rates occur around the middle of the range of total frequencies, and relatively few probes followed stitching sequences, contrasting with the Dunlin studied previously (Burton, in press). Evidently visual signs provided the clues leading to a probe in the major- ity of cases. Stitching thus appeared a relatively inefficient method of locating prey in this area, though it may have been more important near the edges of the pool, where prey were possibly deeper lying. In other situations, and especially at night, it may well be of much greater value.
Table 1. Summary of timed observations on feeding movements of individual Stilt Sandpipers.
|
Rate (Total move- |
Number of |
Combined |
Stitching |
Peci<s |
Probes |
|
|
ments per minu |
te) |
minutes |
totals |
|||
|
10 to 19 |
5 |
79 |
77 |
2 |
0 |
|
|
20 to 29 |
8 |
192 |
123 |
32 |
37 |
|
|
30 to 39 |
14 |
483 |
8 |
197 |
278 |
|
|
40 to 49 |
13 |
598 |
19 |
273 |
306 |
|
|
50 to 59 |
6 |
317 |
34 |
269 |
14 |
|
|
60 to 69 |
3 |
190 |
3 |
151 |
36 |
|
|
70 to 79 |
2 |
145 |
6 |
126 |
13 |
|
|
80 to 89 |
1 |
82 |
0 |
44 |
38 |
|
|
Overall total |
52 |
2086 |
270 (12.9%) |
1094 (52.4%) |
722 (34.5%) |
DOWITCHER
Only two types of feeding action could be distinguished:
a. ya^5.— These are simple, brief movements in which the bill is thrust into the mud and immediately withdrawn.
b. Probes.— More prolonged movements in which the bill is thrust into the mud and held there for a short time, usually accompanied by a rapid up-and-down quivering action.
Probes are generally deeper than jabs, mostly between one third and the full length of the bill (where depth of insertion could be clearly seen), whereas most jabs were to less than half the bill length. However, the main distinction was the brevity of jabs, which were gen- erally too rapid for accurate timing, though apparently under 0.5 seconds in duration. 103 probes timed averaged 1.7 seconds, with maxima of 4.1 and 7.3 seconds.
This classification is to some extent arbitrary, but probably most jabs are trials made in searching for prey by tactile means, while probes include most of the actions in which prey are actually captured. Probes were often grouped in one place. When this was the case, they were often made with obvious vigor, and frequently with the capture of a prey animal, as indicated by swallowing movements. Presumably, in such cases, prey had been located, but
66
several attempts were needed to complete its extraction.
The dowitchers were nearly all feeding in tidal pools, frequently up to belly depth; a few were watched feeding on exposed mud. Though none ever showed the remarkable at- tachment to one spot displayed by some Stilt Sandpipers, their mobility was not great. Most commonly, a bird would concentrate on a small area for about 30 seconds, probing around itself with pivoting movements of the body and a leisurely step or two; then walk on more briskly for a few seconds, and pause to repeat the process. Long series of jabs were some- times made while walking steadily forwards; however, these could not be confused with the stitching of Stilt Sandpipers and Calidris spp., as the frequency of jabs was far less rapid, and the bill was raised well clear of the mud between each.
Rates of feeding movements were generally high. The mean rate during 61 minutes of timed observations (Table 2) was 60.6 (min. 36, max. 110). Not surprisingly, high rates coin- cided with high proportions of jabs. Overall, there were slightly less (48%) jabs than probes. Highest rates were recorded from birds feeding on exposed mud, which employed a high proportion of jabs, and apparently met with little success. Birds feeding in this situation were occasionally seen to make short runs and sudden turns, suggesting pursuit of prey lo- cated by sight.
Between feeding actions, dowitchers held the bill inclined at about 70° or 80° to the horizontal. An attitude with neck outstretched and bill pointed vertically down, as in Stilt Sandpiper was never seen. The orientation of the bill was rarely altered to any significant extent during the course of a probe, though on one occasion the bird turned a full circle around its bill during a single probe. The probes themselves were sometimes made with considerable force and vigor, quite unlike anything seen in the Stilt Sandpiper.
No prey item was at any time seen. Several samples of mud in areas favored by dowit- chers were dug up and carefully sifted, but the only animal species found was the small (5 to 9 mm.) bivalve Lyonsia hyalina Conrad. This moUusk is evidently abundant in the area, and may well have been the main prey of the dowitchers observed.
Table 2. Summary of timed observations on feeding movements of individual dowitchers.
|
Rate (Total movements |
Number of |
Combined |
Jabs |
Probes |
|
per minute) |
minutes |
totals |
||
|
30 to 39 |
2 |
74 |
10 |
64 |
|
40 to 49 |
8 |
359 |
96 |
263 |
|
50 to 59 |
20 |
1099 |
455 |
644 |
|
60 to 69 |
18 |
1164 |
591 |
573 |
|
70 to 79 |
10 |
726 |
402 |
324 |
|
80 to 89 |
2 |
162 |
117 |
45 |
|
110 |
1 |
110 |
93 |
17 |
|
Overall total |
61 |
3694 |
1764 (47.8%) |
1930 (52.2%) |
COMPARISON
Dowitchers and Stilt Sandpipers certainly show some similarities while feeding. Both forage largely in pools and show a generally high rate of feeding movements combined with low mobility. Their feeding actions are mostly simple, fairly regular movements, made more or less straight downwards. The impression of similarity is heightened by contrast with other waders feeding in the same situations, notably Greater and Lesser Yellowlegs, whose brisk actions include dashes and sudden turns.
Nevertheless, there are well marked and important differences. The most obvious of these is the absence of "stitching" in Dowitchers— notwithstanding the fact that the actions of both birds have been likened with some justice to a sewing machine. Despite the sim- ilarity of imagery, it must be remembered that the term "stitching" as used here and else-
67
where (Burton 1971, and in press) applies specificially to an extremely rapid series of shal- low jabs, made with minimum head movement. This action, seen in many calidridine sandpipers, including the Stilt Sandpiper, was never observed from dowitchers during the course of these observations. Conversely, Stilt Sandpipers rarely used deep test probes, whereas the jabs of dowitchers regularly penetrate to a third or more of their considerable bill length. Probes in both species are made with a similar quivering action, but Stilt Sand- pipers never exhibit the vigor and forcefulness which is often shown by probing Dowitchers.
The attitude with neck outstretched and bill pointed perpendicularly down is charac- teristic of Stilt Sandpipers but is rarely shown by Dowitchers. As explained earlier, this atti- tude is probably connected with hunting by sight, and indicates the much greater impor- tance of vision for feeding in the Stilt Sandpiper— a factor which underlies other differences between their feeding techniques. Stitching as a means of tactile foraging increases the chances of contact with prey lying near the surface in a given time, but must be relatively inefficient for detecting deeper lying prey. The individual jabs in a stitching series are shal- low, and probably only penetrate the soft surface layer of water covered mud; they require relatively little anatomical specialization, and form part of a generally more versatile range of feeding techniques. The generally deeper jabs of dowitchers stand a greater chance of detecting deep lying prey, but there are many fewer in a given time. Also, since the head is fully raised and lowered between each one, and the deeper penetration involves entering a harder substrate, the amount of energy expended in proportion to the number of contacts with prey may well be greater in dowitchers. This is probably offset to some extent by greater tactile sensitivity in dowitchers. Moreover, dowitchers are capable of handling con- siderably larger prey than Stilt Sandpipers, and since these tend to be deeper lying dowit- chers may be expected to encounter more of them. The feeding technique and anatomy of dowitchers thus probably depends on relatively infrequent contacts with larger prey.
Detailed information on anatomy of the feeding apparatus in shorebirds is given by Kozlova (1961-62) and Burton (in press). The points of difference between dowitchers and Stilt Sandpipers summarized below appear particularly relevant to a comparison of feeding methods.
a. The bill axis is considerably more downwardly directed relative to the cranium in dowitchers.
b. The dorsal bar of the upper jaw is greatly reinforced in dowitchers, and is almost in contact with the ventral bar. In the Stilt Sandpiper, both ventral and dorsal bars are thin and widely separated.
c. Hexagonal pits, indicating clusters of tactile receptors (Herbst's corpuscles) are much more numerous at the tips of the jaws in dowitchers.
d. M. protractor quadrati, which raises the tip of the upper jaw, is enormous in dowit- chers by comparison with the Stilt Sandpiper.
e. M. adductor externus (of major importance for jaw closure and gripping prey) is rela- tively larger in dowitchers, and of more complex structure, with more pinnate fiber arrangements— a modification to increase the force of contraction over short distances.
f. M. rectus capitis superior, a flexor of the head and anterior part of the neck, lacks at- tachment to vertebra 4 in the Stilt Sandpiper. This curious feature, unique among shorebirds, is probably connected with its characteristic head attitude with bill pointed straight down, while feeding in water.
In most of these, and other anatomical features of head and neck, the Stih Sandpiper is typical of the Calidridinae, whereas dowitchers closely approach the Scolopacinae, though showing some similarity to members of the Tringinae. Dowitchers have by some authors (e.g., Kozlova. 1961-2) been considered more closely allied to godwits, but Jehl (1968) has produced strong evidence for their close relationship to the Scolopacinae, first proposed by Lowe ( 1931). The results of this study bear out Jehl's view. The feeding technique of dowit- chers closely resembles that of Snipe (Gallinago gallinago ), described in detail by Burton (in press), in the great reliance of both on simple probing, and in the manner, timing, and dis- position of probes. They certainly show little resemblance to the versatile techniques of the much more mobile godwits. Similarly, the feeding behavior of Stilt Sandpipers, with its frequent use of "stitching" is very similar to that of other Calidridinae, though with modifi-
68
cations for feeding in deeper water than most of the subfamily.
In any further study of feeding in dowitchers and Stilt Sandpipers, it would be desir- able to observe them in an area where both forage together. I saw them in close proximity on various stretches of shore in the Laguna Atascosa Refuge, but was not able to prolong my observations there. Such a comparison might throw further light on the results obtained by Recher (1966) in a comparison of waders sharing a stretch of shore. It would be particu- larly interesting to know whether dowitchers (the larger species) take a narrower spectrum of prey, including more large items, than the Stilt Sandpiper. Such a difference might be expected from Recher's analysis of diets in relation to body size, though in the experience of Jehl (pers.comm.) the reverse seems to be the case at Churchill, Manitoba, where the two species often feed in close proximity.
ACKNOWLEDGMENTS
I am deeply indebted to Mr. and Mrs. John J. Morony and John J. Morony, Jr. and to Mr. and Mrs. John Arvin; their kindness and hospitahty during my visit to Texas made this study possible. I am grateful to Mr. J. Peake of the British Museum (Natural History) for identifying the mollusk collected at Padre Island.
LITERATURE CITED
Bent, A.C.
1927. Life histories of North American Shore Birds. Part I. U.S. Natl. Mus. Bull. 146.
Burton, P. J. K.
1969. Anatomy and adaptive modifications of the feeding apparatus in waders (Aves: Charadrii). Ph.D. thesis. University of London.
1971. Comparative anatomy of head and neck in the Spoon-billed sandpiper, Eurynorhynchus pygmeus and its allies. J. Zool., Lond., 163: 145-163.
In press. Feeding and the feeding apparatus in waders. British Museum (Natural History).
Holmes, R. T.
1966. Feeding ecology of the Red-Backed Sandpiper {Calidris alpina) in Arctic Alaska. Ecology, 47: 32-45.
Jehl, J. R., Jr.
1968. Relationships in the Charadrii (shorebirds): a taxonomic study based on color patterns of the downy young. San Diego Soc. Nat. Hist., Memoir 3.
Kozlova, E. V.
1961-1962. Fauna S. S. S. R., Zool. Inst. Akad. Nauk S. S. S. R., nov. ser. no. 81, Ptitsy, 2, no. 1, pt. 3 [Birds, Charadriiformes. Suborder Limicolae] Moscow-Leningrad. Akad. Nauk. S. S. S. R.
Lowe, P. R.
1931. An anatomical review of the "waders" (Telmatomorphae). Ibis, 1931: 721-771.
Palmer, R. S.
1967. Species accounts, In G. D. Stout (ed.). The Shorebirds of North America. Viking Press, New York.
Peters, J. L.
1934. Check-list of birds of the world. Vol. 2. Harvard Univ. Press, Cambridge.
Peterson, R. T.
1947. A Field Guide to the Birds. Houghton-Mifflin Co., Boston.
Recher, H. F.
1966. Some aspects of the ecology of migrant shorebirds. Ecology 47: 393-407.
Streefkerk, C. J.
1960. Verslag van het vergelijkend onderzoek naar de wijze van voedsel zoeken van enige soorten steltlopers. Uitgegeven door de Christelijke Jeugdbond van Natuurvrienden, Amsterdam.
Sub-Department of Ornithology, British Museum (Natural History), Tring, Hertford- shire, England.
cS4a/
UBRARY
THORACIC CIRRIPEDIA FROM GUYOTS OF THE MID-PACIFIC MOUNTAINS
M. V. LAKSHMANA RAO AND WILLIAM A. NEWMAN
TRANSACTIONS
OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
VOL. 17, NO. 6 31 AUGUST 1972
THORACIC CIRRIPEDIA FROM GUYOTS OF THE MID-PACIFIC MOUNTAINS
M. V. LAKSHMANA RAO AND WILLIAM A. NEWMAN
ABSTRACT.— Knowledge of the fauna of oceanic seamounts is meager. To determine whether seamounts serve as stepping stones for the distribution and dispersal of sedentary faunas across oceanic barriers, and their role in the biogeography and speciation of deep-sea faunas, an expedition went to the Mid-Pacific Mountains in the summer of 1968. This paper reports on Thoracic Cirripedia from six guyots located there. Nine species were identified, of which four are new. Three of the new species are allied to forms from the Indo-Pacific; the fourth is closely related to a Hawaiian species. Of the five previously known species, two are widely distributed in the Indo-Pacific, two are cosmopohtan and one is endemic to Hawaii. Thus, the affinities of the cirripeds are predominantly Indo-Pacific.
Virtually nothing is known of the faunas of submarine archipelagos. One would like to know specifically what role seamounts serve as stepping stones at bathyal depths, what im- portance they have in the evolution of deep-sea faunas, and to what degree these faunas tend to be endemic. In the summer of 1968, Wilham A. Newman and Richard H. Rosen- blatt, both of the Scripps Institution of Oceanography, John A. Allen of the Dove Marine Laboratory, England, and the late Edwin C. Allison of San Diego State College, and Harry S. Ladd of the U.S. Geological Survey staged an expedition (Styx-Leg 7) aboard the R/ V Alexander Agassiz to investigate both recent and extmct faunas of the Mid-Pacific Moun- tains.
The Mid-Pacific Mountains are a chain of seamounts located between 17° and 23°N, with the main axis extending between 165° W and 170°E for some 2,780 km (Fig. 1). This chain of seamounts, part of the Marcus-Necker Ridge, forms the northeastern portion of the region designated as the Darwin Rise (Menard, 1964). Numerous flat-topped seamounts occur along this chain at depths ranging between approximately 1,000 and 1,700 m. Shallow water megafossils taken by dredging indicate that many flat-topped seamounts are guyots, land forms produced by subaerial erosion and marine planation at a time when they broke the sea surface. The fossils, particularly the rudist molluscs and associated or- ganisms such as corals, indicate that the seamounts persisted as shaflow water banks and reefs up to the mid-Cretaceous before subsiding more than a kilometer to their present depths (Hamilton, 1956). Prior to this time, the Mid-Pacific Mountains formed an extensive island chain, comparable to the present Hawaiian Archipelago. Since formation, the chain has migrated northwest some 25° to its present position (Lonsdale et ai, 1972). Con- sequently the chain has always been beneath tropical waters.
The tops of the guyots have been altered to varying degrees since they subsided (Karig et ai, 1970; Lonsdale et ai, 1972). Virtually all exposed hard surfaces, such as rudist reefs, limestone, exhumed chert and basalt outcrops are covered with ferromanganese oxides of varying thickness. For some reason fresh manganese-coated surfaces appear unfavorable for attachment of benthic organisms and the numerous large slabs and nodules dredged from the Mid-Pacific Mountains were devoid of them. Generally pieces of pumice, appar- ently of recent origin, and occasional small rocks (cherts) are free of manganese coatings. Otherwise, uncoated hard surfaces on which sedentary organisms might be expected to settle and attach are hmited to the hard parts of living organisms such as spicules of si- liceous sponges, shells of gastropods, barnacles and corals usually occurring on soft sedi- ments. In the present collection cirripeds were taken from all these with the exception of the corals.
SampHng methods were varied. Pipe and chain-bag dredges were employed on hard bottoms and outcrops; otter and beam trawls over soft bottoms. A variety of benthic in- vertebrates was recovered and the present paper reports on the class Cirripedia. Only mem-
SAN DIEGO SOC. NAT. HIST, TRANS. 17(6); 69-94, 31 AUGUST 1972
70
25°
350CX 1464
Horizon Guyot
170°E
180
70° W
Figure 1. Chart indicating the location of the guyots sampled on the Mid-Pacific Mountains during the Styx-7 Expedition. Depths in meters. Numerous other guyots in the region not indicated. Of the guyots indicated, only Darwin, Hess and Horizon have been named previously.
bers of the order Thoracica were encountered on the six guyots sampled (Table 1). (Station numbers for this leg of the expedition were numerical: year, month, day, 1, 2 or 3 etc.).
Of the nine identifiable species found, four are new, the relative number of new species being comparable to that of the Antarctic (Newman and Ross, 1971), One cannot assume that all four new species from the Mid-Pacific Mountains are endemic to the region because knowledge of deep-sea cirripeds is meager (see Zevina, 1972). While one of the new species is most closely related to a species known previously only from Hawaii, the remaining three show close affinities with forms widely distributed in the Indo-Pacific. Of the five previously known species, two are known from the Indo-Pacific, one from Hawaii (and thus perhaps an Indo-West Pacific derivative endemic to Hawaii), and two are cosmopolitan. Thus, as one might have anticipated, the affinities of the cirriped fauna of the Mid-Pacific Mountains are primarily with the Indo-Pacific. The fishes show comparable affinities (R.H. Rosenblatt, pers. comm.).
While virtually nothing is known of the faunas of other submarine archipelagos, the fauna of Shoal Guyot, situated at approximately 25° S, 85° W, some 1,300 km west of South America at a depth of 288 m, is relatively well known and is of considerable bio- geographic interest. Hubbs ( 1959) published on fishes, and information on echinoderms and barnacles was given by Zullo et al. (1964), Zullo and Newman (1964) and Allison et al. ( 1967). One might have expected the fauna of Shoal Guyot to be strongly Eastern Pacific in character since it is separated from the Indo-Pacific by the so-called East Pacific Barrier. To the contrary however, it proved to be primarily an eastward extension of the Indo-West Pacific and thus would appear to be the eastern terminus of a series of submarine stepping stones at bathyal depths across the East Pacific Barrier (AUison et al, 1967). The situation is more complicated than this however, for there is apparently a peculiar extension of neretic plankton toward this region from the west (A. Fleminger, pers. comm.), and this indicates that the eastward extension of the Indo-Pacific fauna is not simply by way of submarine stepping stones in this region, as previously supposed.
SYSTEMATIC ACCOUNT
Order Thoracica Darwin, 1854
Suborder Lepadomorpha Pilsbry, 1916
Family Scalpellidae Pilsbry, 1916
Genus A rcoscalpelluni Hoek, 1907
Arcoscalpellum alcockianum (Annandale), 1905 Figures 2 and 1 IG
ScalpeUitm alcockianum ^x\nlm&^\Q. 1905:82; 1906a: 138; 1906b:392: 1913:229; 1916: 129, pi. vi, man, 1918a:115; Nilsson-Cantell, 1928:6; 1931:2; 1938:7.
fig. 5; Cal-
71
Table I. Cirripedia from guyots of the Mid-Pacific Mountains
|
Species |
Horizon |
Hess |
Allison |
Agassiz |
Sio Darwin |
Previously known distributions |
Sources |
|
LEPADOMORPHA Family: Scalpellidae |
|||||||
|
l.'^Arcoscalpellum sp. |
1718m |
Present report |
|||||
|
l.ArcoscalpMum alcockianum i.Arcoscatpellum etegqntissimum n. sp. |
1652- 1670m |
1418- 1664m |
1566m |
Indian Ocean ; Mozambique Channel; Gulf of Manaar; Bay of Bengal; Malay Archipelago, SW Pacific Ocean; (109S-1800m) Lukunor Atoll. Caroline Islands; (972m) (present report) |
Annandale (1906); Caiman (1918a); Nilsson^'antell (1938) Present report |
||
|
A.Arcoscalpellum hawaiiense |
1415- 1557m |
Hawaii; (1460m) |
Pilsbry (1907a) |
||||
|
S.Arcoscatpellum michelottianum |
1584- 1800m |
1692- 1735m |
1413- 1645 m |
1557m |
Cosmopolitan - Atlantic, Indian, Pacific and Antarctic Oceans; (40-2900m) |
Nilsson-CanteU (1938); Newman and Ross (1971) |
|
|
S.Arcoscalpellum radiatum |
1584- 1800m |
1413- 1645m |
Present report |
||||
|
1 .Arcoscalpellum rossi n. sp. |
1692- 1735m |
1413- 1645m |
Present report |
||||
|
S.Mesoscatpellum gruvelii Family: Poecilasmalidac |
1429- 1663m |
Indian Ocean; Gulf of Aden; Laccadives; Gulf of Manaar; Andaman Sea; (794-2268m) |
Nilsson-Cantell (1938) |
||||
|
9.Megalasma (Glyptelasma) pihbryi |
1445- 1557m |
Indian Ocean; Malay Archipelago; Pacific and Atlantic Oceans; (1098-1647m) |
Nilsson-Cantell (1938) |
||||
|
VERRUCOMORPHA |
|||||||
|
10. Verruca {Altiverruca) allisoni n. sp. |
1718- 1770m |
1413- 1645 m |
1300- 1353m |
Present report |
Material. -Slyx-7, 680903-04 Sta. 1. Allison Guyot ( 18°3rN, 179°36'W), 1418-1664 m (otter trawl). One her- maphrodite on long glassy spicules of a siliceous sponge.
Supplementary description (hermaphrodite).— The capitular plates were adequately de- scribed by Annandale (1906b). Evidently the capitulum and the peduncle are subject to considerable variation (Annandale, 1913; Nilsson-Cantell, 1928). In the present specimen as compared to those shown by Annandale (1916), tergum is not as reduced, the scutal mar- gin is hollowed out, and the carinal margin is angular and recedes from the carina both above and below. The scutum is not fully calcified, and the calcified portion is triangular, reaching to the lower extremity of the occludent margin of the tergum; the apex is terminal. A rostrum is present.
The peduncle is cylindrical, almost as high as the capitulum and armed with about 13 rows of transversely elongate plates. There is no basal disc in the present specimen, appar- ently reflecting the substrate to which the specimen is attached.
Of the arthropodal structures brief descriptions were given by Annandale and Nilsson- Cantell together with figures of the mandible, maxillae and caudal appendages. The follow- ing account and accompanying figures are supplementary.
Labrum bullate, very broad distally and mottled by pigment all over the surface; teeth very small; palp elongate, pointed at the tip and covered with plumose spines along the entire margin (Fig. 2D). Maxilla I having nearly straight cutting edge divided into two steps with about 13 strong spines above, and approximately 10 strong and 18 weaker spines of about equal length below (Fig. 2E). Maxilla II large, with superior margin long, supporting a continuous row of spines; a medial notch as noticed by Nilsson-Cantell ( 1928); maxillary lobe short, broad and truncate apically (Fig. 2F). Mandible with four teeth including infe- rior angle; first tooth well separated from second, third tooth nearer to inferior angle than to second (Fig. 2B); inferior angle supporting 30-31 short blunt subspatulate spines some of which are bifid (Fig. 2C).
Cirrus I widely separated from the rest; intermediate segments of the anterior ramus strongly protuberant, those of the posterior ramus cylindrical and 2/3 as wide; both rami prominently hairy (Fig. 2A). Cirrus II nearly Wi times as long as cirrus I and cirrus III a little longer than the second. Cirri V and VI with terminal segments missing. Segment 18 of cirrus VI is figured (Fig. 2G); articular areas along greater curvature with 2-4 long and 1-2 short setae; lateral faces with a few short setae; interarticular areas devoid of setae and bristles. Setation ctenopod; four major pairs of setae along lesser curvature. Between each
72
Figure 2. Arcoscalpellum alcockianum (Annandale), Styx-7, 680903-04 Sta. 1. A, cirrus I; B, mandible: C, third tooth and inferior angle of mandible; D, palp; E, maxilla I; F, maxilla II; G, intermediate articles of cirrus VI; H, caudal appendage; I, penis.
major pair there are 1-2 long bristles. Caudal appendage of 29 segments reaching to at least half the length of cirrus VI. Each segment with 1-5 setae along outer margin, terminal seg- ment with a tuft of 5 short setae at tip (Fig. 2H).
Penis short, moderately stout, covered with small hairs and annulated in the proximal part; distal end narrow and covered with minute hairs (Fig. 21).
Two complemental males were recovered, one from each pouch near the tip of the in-
73
side of each scutum. The male is sac-like, without traces of valves or cirri, but the mantle is covered with rows of spines and supports two prehensile antennae at the middle of the ven- tral margin.
Remarks.— This species is apparently distributed widely in the Indian Ocean, having been reported several times from the Bay of Bengal and Malay Archipelago. The only record outside of this area is in an unpublished report by Caiman on specimens taken be- tween Australia and New Zealand (Nilsson-Cantell, 1928). The present report extends its range far east into the Pacific.
Arcoscalpellum giganteum (Gruvel) from the Atlantic is closely related, but its tergum is much hollowed and the caudal appendage consists of only four segments.
Arcoscalpellum elegantissimum n. sp.
Figure 3
Malerial.-Styx-l. 680907 Sta. 1, Agassiz Guyot (17°50.6' N, 178°25.0' W), 1566 m (otter trawl) 1 spec; 680829 Sta. 3. Horizon Guyot (19°28.0' N. 168°52.3' W). 1652-1670 m (rock dredge), 1 spec; CARMARSEL Exped. Sta. 815 (off Lukunor Atoll, Caroline Islands, 10 March 1967), 972 m, 2 spec.
Depositorv.-V.S.NM. no. 140943 (Holotype. Stvx-7, 680907, Sta. 1) U.S.N.M. no. 140944 (Paratype, Styx-7, 680829, Sta. 3,' 1 spec.) U.S.N.M. nos. 140945, 140946 (CARMARSEL Exped. Sta. 815, 2 spec)
Diagnosis.— Capitulum with 14 fully calcified approximate plates ornamented with strong radial ridges. Carina broad basally; carinal roof traversed by longitudinal ridges; parietes well developed. Carinal latus as broad as high. Rostral latus wider than high. Ros- trum ovotriangular and fully exposed. Inframedian latus higher than rostral latus but shorter than carinal latus. Mandible with 4 teeth including inferior angle. Maxilla I with straight cutting edge. Intermediate segments of cirrus VI with 2-3 major and 1 minor pair of setae. Caudal appendages with 4 partially fused segments reaching % the length of first seg- ment of pedicel of cirrus VI.
Description (female).— Capitulum globose, ovally elongate, apically pointed, hirsute especially on the carinal side; 14 fully calcified plates, white, with no indication of a per- sistent cuticle. Plates ornamented with prominent ridges, radiating from the umbones, in- tersected by faint growth lines (Fig. 3 A).
Tergum nearly twice the area of the scutum, rhomboid, twice as long as wide; apex prominently acute; basicarinal angle reaching about % the distance towards the base of the capitulum, nearly to the lower whorl of the plates; lateral margin partly overlapped by the upper latus. Scutum subquadrate, more than twice as long as broad; surface convex, ap- pearing divided into halves by a diagonal angulation running from the umbo to the basil- ateral angle. Carina strongly bowed, broad basally, tapering towards apex; roof essentially fiat, traversed by prominent longitudinal ridges; parietes well developed and also promi- nently ridged. Carinal latera meet for a short distance at base of carina forming a broad V- shaped margin (Fig.3B); each as broad as high, with an inwardly curved apex which pro- jects slightly beyond the surface of the capitulum; basal and lateral margins irregular; two ledges running from umbo to base divide plate into two parts, a shallow wing-like expan- sion at base of upper latus and two triangular areas (one a raised carinal part adjoining the carina and the other a concave middle portion between this and the wing-like portion). In- framedian latus triangular, slightly higher than broad; apex raised above the surface of ca- pitulum and curved inwards. Rostral latus twice as broad as high; scutal and basal margins subparallel; plate diagonally divided into halves by a faint ridge; apices of both sides partly overlapped by rostrum (Fig. 3C). Rostrum ovotriangular, broad at anterior end and narrow posteriorly (Fig. 3C). Peduncle short, Va height of capitulum and armored with 8-10 rows of 4-5 closely packed, narrow and elongate scales. Measurements (in mm) of the holotype fol- low: overall height, 16.5: height of capitulum, 13.0: height of peduncle, 4.0.
Labrum bullate, no soft setae present; crest armed with about 45 teeth. Palp elongate, triangular, somewhat rounded distally; proximal superior margin with short stiff bristles; distal border with long setae (Fig. 3H). Mandible with four teeth including inferior angle; second tooth well separated from first (Fig. 3D); inferior angle with 13-15 triangular to sub- spatulate teeth a few of which are bifid (Fig. 3E). Maxilla I with cutting edge feebly concave above and convex below; concave part supports 2 long, stout and 3-4 shorter, thinner spines (Fig. 3F). Maxilla II triangular in shape, lobes weakly developed; marginal setae dis-
74
^^^i!^-^^
|
,AC |
5.0 mm |
||
|
,B ,DFHIJ |
SO |
0.5 |
|
|
,E |
0.2 |
||
|
,6 |
_0.5 |
||
|
,K |
0.5 |
Figure 3. Arcoscalpellum elegantissimum n. sp., Holotype, Styx-7 680907 Sta. 1, Agassiz Guyot. A, side view of female; B, carinal view; C, rostral view; D, mandible; E, third tooth and inferior angle of mandible; F, maxilla I; G, maxilla 11; H, palp; 1, cirrus I; J, intermediate articles of cirrus VI; K. caudal appendage.
tributed in three clusters, but those of the superior and distal borders are contiguous; max- illary lobe short, broad and truncate apically (Fig. 3G).
Cirrus I well separated from the rest; anterior ramus shorter than posterior; inter- mediate segments of anterior ramus protuberant, those of posterior cylindrical and % as
75
wide; both rami clothed with long setae (Fig. 31). Cirrus II normal. Cirri IV-VI nearly equal in length with equal or sub-equal rami. Each articulation along greater curvature of inter- mediate articles of Cirrus VI supporting 4-5 short slender setae. Interarticular areas along greater curvature and lateral faces free of setae. Setation ctenopod; 2-3 major pairs and 1 minor pair with 1-2 slender spines at bases of major setae (Fig. 3J). Caudal appendage com- posed of 4 stout, partially fused segments, extending about % length of pedicel of Cirrus VI; distal article with tuft of 3-5 setae, 2 or 3 being longer than appendage (Fig. 3K). Cirral counts of the four specimens follow:
I II III IV V VI Ca
|
Styx-7 680907 |
8 |
22 |
22 |
24 |
25 |
25 |
|
Sta. 1 Agassiz Guyot (Holotype) |
12 8 13 |
20 21 22 |
21 22 24 |
25 21 25 |
17+ 22 24 |
26 26 26 |
|
Styx-7 680829 |
7 |
20 |
23 |
25 |
15+ |
25 |
|
Sta. 3 (Paratype) |
12 |
20 |
23 |
22 |
23 |
23 |
|
7 |
20 |
22 |
13+ |
23 |
23 |
|
|
12 |
20 |
23 |
23 |
23 |
23 |
|
|
CARMARSELSta. 815 |
8 |
20 |
22 |
22 |
24 |
25 |
|
(Paratype) |
12 |
20 |
21 |
22 |
24 |
25 |
|
7 |
16+ |
21 |
22 |
16+ |
12+ |
|
|
12 |
19 |
21 |
22 |
23 |
23 |
|
|
CARMARSELSta. 815 |
7 |
15 |
16 |
16 |
17 |
17 |
|
(Paratype) |
9 |
15 |
15 |
15 |
17 |
17 |
|
7 |
14 |
15 |
16 |
15 |
17 |
|
|
9 |
14 |
15 |
18 |
17 |
18 |
Remarks.— Arcoscalpellum elegantissimum is closely related to the A. michelottianum group of scalpeUids (Newman and Ross, 1971). Important uniting characters are: a promi- nently hirsute capitulum, a triangular inframedian latus not exceeding the height of the carinal latus and with an apical umbo, carinal lateral plates not interdigitating where they meet below the carina, and a rostral latus almost twice as wide as high. The new species is closely alhed to^. hawaiiense {ViX^ibry) but differs in having: 1) apex of carinal latus curved inwards, not projecting beyond the base of the carina; 2) posterior ramus of cirrus I only slightly longer than the anterior ramus but with \Vi times as many segments; 3) caudal ap- pendage with but four incompletely fused segments and less than the height of the first segment of the pedicel; 4) scales on the peduncle not overlapping or imbricating and 5) a much smaller size. In its small size and the general nature of the arthropodal structures /i. elegantissimum shows some resemblance to A. hirsutum (Hoek). However, in the latter spe- cies the roof of the carina does not possess longitudinal ridges and the carinal latus is less elaborately developed.
The specific name refers to the elegant capitular ornamentation.
Arcoscalpellum hawaiiense (Pilsbry), 1907 Figures 4 and 1 1 C-D
Scalpellum hawaiiense Pilsbry 1907a: 181. pi. IV, fig. 1-2.
Material. -Styx-7, 680905 Sta. 2, Allison Guyot ( 179°37.r W, 18°35.4' N) 1450-1557 m (otter trawl). 1 spec, attached to a small rock.
Supplementary description (female).— The capitular structure of this scalpellid agrees well with the description of the type from Kauai, Hawaii (Pilsbry, 1907a). The present spec- imen, larger than the type, has the following dimensions (in mm): overall height, 44; capitu- lar height, 3 1 ; width of capitulum, 22; height of peduncle, 14.
The arthropodal structures were not described and are dealt with here. Labrum bul- late, longer than broad, apex gently curving, surface mottled with pigment. Palp long and narrow, superior and anterior margins clothed with thick, short, slightly plumose setae; an-
76
terior margin and lateral faces naked (Fig. 4F). Mandible with 4 teeth including inferior angle; teeth more or less equidistantly spaced (Fig. 4B); inferior angle supporting about 14 teeth many of which are worn and blunt (Fig. 4C). Maxilla I with cutting edge nearly straight without evident notch; upper half supporting 7 spines, the uppermost 2 long and stout, the rest shorter and thinner; lower portion supporting 17-18 long and short spines (Fig. 4D). Maxilla II triangular, with 3 weakly developed lobes; marginal setae distributed in three clusters, those of superior and anterior margins being longer; lateral faces devoid of setae (Fig. 4E).
Cirrus I widely separated from the rest; posterior ramus IVi times longer than ante- rior ramus; intermediate segments of anterior ramus strongly protuberant, those of pos- terior ramus cylindrical and % as wide (Fig. 4A). Cirrus II normal. Cirri III-IV about equal in length with equal or subequal rami. Each articulation along greater curvature of inter- mediate segments of cirrus VI with a cluster of 2-5 short setae. Setation ctenopod; 3 major pairs of setae along lesser curvature, a pair of long slender setae at base of distal pair and 2-3 short bristles at bases of all major pairs (Fig. 4G). Caudal appendage of six segments, each with 1-3 spines, reaching to about Vi length of second segment of pedicel of cirrus VI. Ter- minal segment with a tuft of 4 long and 2-3 short, slender setae (Fig. 4H). Cirral counts are as follows:
II III IV V VI Ca
Styx-7 680905 Sta. 2
|
9 |
28 |
33 |
32 |
36 |
40 |
|
17 |
27 |
32 |
32 |
34 |
40 |
|
9 |
28 |
30 |
33 |
34 |
40 |
|
17 |
28 |
32 |
34 |
36 |
40 |
Eight dwarf males were recovered, four from each pouch on the inside of the distal end of the scutal plates. The males are sac-like, devoid of plates but covered with rows of spines.
Remarks.— This is the second report of A. hawaiiense which was originally dredged off Kauai, Hawaii at a depth of 1460 m. Though Pilsbry (1907a) did not describe the mouth parts and cirri, the capitular structure of our specimen agrees almost point for point with the description of the type specimen. The bathymetry also agrees. Pilsbry drew attention to the relationship between A. hawaiiense, A. rubrum (Hoek) and A. hirsutum (Hoek). In a later publication he (Pilsbry, 1911) included these species under the group of Scalpellum vehiti- num. With this we concur. However, a detailed comparison of ^4. hawaiiense from Allison Guyot with more complete descriptions of^. rubrum (Pilsbry, 1911) andv4. hirsutum (New- man and Ross, 1971) shows that the resemblance is rather superficial, there being several differences in the capitular structure, mouth parts and cirri. ArcoscalpeUum hawaiiense shows close resemblance to A. elegantissimum n. sp. While closely related, these can be distinguished from one another by the following characters; A. hawaiiense has 1) the apex of the carinal latus projecting, though slightly, away from the carina; 2) close and imbricat- ing scales of the peduncle; 3) posterior ramus of cirrus I, Wi times longer than the anterior and composed of nearly double the number of segments, 4) a caudal appendage composed of 6 segments and reaching to about Vi the length of second segment of the pedicel of cirrus VI, and 5) a much larger overall size.
ArcoscalpeUum wyethi (Cornwall) from Guam appears to be a related form, but in this species the carinal latera project strongly beyond the base of carina, the scales on the pe- duncle do not overlap and are widely spaced, and the intermediate articles of cirrus VI sup- port 5 pairs of setae instead of 3 pairs as in ^4. hawaiiense.
ArcoscalpeUum michelottianum (Seguenza), 1876 Figures 5 and 1 1 A-B
Scalpellum michelotiianum Seguenza, 1876:381, pi. 6, figs. 15-25: 464, pi. 10, fig. 26; ArcoscalpeUum mich- elottianum: Newman and Ross, 1971: 71, pi. IXB, text-fig. 34 (see this reference for complete synonymy of this species).
A/a/ma/.-Styx-7,680901 Sta. 3, Hess Guyot ( 174°24.8' W; 17°53.2' N), 1692-1735 m (Sigsbeebeam trawl), 1 spec; 680903-04 Sta. 1, Allison Guyot ( 179°36.0' W; 18°31.0" N); 1413-1645 m (otter trawl), 2 spec; 680905 Sta. 2, Allison Guvot (179°37.r W; 18°35.4' N), 1413-1449 m (otter trawl), several spec; 680907 Sta. 4. Agassiz Guyot (178° 14.2' W; 17°58.5' N), 1557 m (Sigsbee beam trawl), 1 spec
Supplementary description (female).— The large series of specimens agree closely with
77
.S.Oinm
iBEFBH
.1.0
_0.5
.1.0
Figure 4. Arcoscalpellum hawaiiense (Pilsbry), Styx-7, 680905. Sta. 2, Allison Guyot. A, cirrus I; B, mandible; C. third tooth and inferior angle of mandible; D, maxilla I; E, maxilla II; F, palp; G, intermediate articles of cirrus VI; H, caudal appendage.
the descriptions of Scalpellum eximium Hoek {= Arcoscalpellum michelottianum). The lengthy synonymy under /i. michelottianum (see Newman and Ross, 1971) indicates that this species is not only variable but that also several species were confused with and in- cluded in it. Because of this it is important that the specimens from the Mid-Pacific be carefully characterized, for the synonymy problem will undoubtedly continue.
Capitulum robust, thick near the peduncle and flatter towards the apex; surface cov- ered by a yellow to olive colored cuticle, velvety to touch, prominently hairy in young indi- viduals and sparsely so in older ones; 14 fully calcified plates usually fully approximate, but in some specimens carina separated from others by a narrow chitinous interspace (Fig. 1 IB). Scutum trapeziform; \Vi-2 times as long as broad, divided into two parts by a faint diagonal ridge running from umbo to basilateral angle. Carina strongly bowed, nar- row apically and gradually increasing in width towards base; roof gently convex and trav- ersed by an indistinct longitudinal median ridge and marked by V-shaped growth lines; parietes well developed and sculptured with 4-6 distinct longitudinal ridges; base triangu- lar and enters as a wedge between carinal latera (Fig. 1 1 A). Carinal latus irregular; umbo at recurved apex which, in some specimens, is raised above surface of capitulum; plate divided into three parts by two ridges running from umbo to basal margin. Inframedian latus as high or slightly higher than wide; apex usually curved downwards. Form of plate
78
|
,ABCEGH |
10 mm |
|
|
.DiKLM |
■) n |
|
|
.F |
SO |
|
|
.1 |
Figure 5. Arcoscalpellum micheloiiianum {Seguenzd). Styx-7, 680901, Sta. 3, Hess Guyot. A, palp; B, maxilla I; C, maxilla 11; D. mandible; E, inferior angle and third tooth of mandible; F, cirrus I; G, dwarf male; H. intermediate articles of cirrus VI; I. caudal appendage; J-M, side view of females.
changes considerably with growth (Fig. 5L-M). Rostral latus shorter than height of infra- median latus; broad and divided into two parts by a ridge running from umbo to lateral margin. Rostrum appearing externally in young individuals, lanceolate in shape; umbo apical. With growth, rostrum is overlapped by rostral latera of both sides and becomes hidden. Peduncle long; scales closely set or widely spaced, completely covered by a mem-
79
brane or partly projecting through it.
The measurements (in mm) of four dissected individuals are given below:
|
Station (Styx-7) |
680901 |
680903-04 |
680903-04 |
680907 |
|
Sta. 3 |
Sta. 1 |
Sta. 1 |
Sta. 4 |
|
|
Overall height |
53 |
58 |
22 |
50 |
|
Height of capitulum |
30 |
36 |
16 |
32 |
|
Height of peduncle |
25 |
25 |
8 |
20 |
Labrum buUate; palp triangular, rather broad and short, superior and distal margins covered with long plumose spines, inferior margin naked (Fig. 5A). Maxilla I with cutting edge nearly straight; spines distributed in three indistinct sets; upper margin supporting 2 long stout and 5 short spines; intermediate set consisting of 1 long and 2 short spines; lower margin with a set of 1 long and 9-1 1 short spines (Fig. 5B). Mandible with four teeth in- cluding inferior angle; teeth spaced nearly equidistant from one another (Fig. 5D); inferior angle supporting 22-25 bluntly pointed teeth (Fig. 5E). Maxilla II broadly triangular, setae distributed in three clusters, those of superior and distal lobes contiguous; maxillary lobe broad, short and truncate apically (Fig. 5C).
Cirrus I widely separated from others; intermediate segments of anterior ramus strongly protuberant, those of posterior ramus moniliform and % as wide (Fig. 5F). Cirrus II normal, almost twice length of cirrus I. Cirri III-VI subequal with equal or subequal rami; articular areas along greater curvature have 3-4 long plumose setae; lateral faces with 2-5 rows of setae; setation ctenopod, three major pairs and one minor pair along lesser curva- ture; 2-3 short setae between major pairs (Fig. 5H). Caudal appendage of 4 incompletely fused segments, less than height of first segment of pedicel of cirrus VI; distally, articular areas with 2-4 spines on the outer margin; third segment with one long and one short seta on distal margin; distal segment with a tuft of 7-8 long plumose setae (Fig. 51). Cirral counts of four dissected specimens follow:
I II III IV V VI Ca
|
Styx-7 680901 |
8 |
26 |
31 |
35 |
18+ |
17+ |
|
Sta. 3 |
13 |
29 |
30 |
25+ |
20+ |
16+ |
|
8 |
28 |
30 |
35 |
18+ |
18+ |
|
|
13 |
27+ |
31 |
26+ |
18+ |
19+ |
|
|
Styx-7 680903-04 |
8 |
26 |
30 |
35 |
19+ |
18+ |
|
Sta. 1 (spec. 1) |
13 |
30 |
31 |
25+ |
22+ |
18+ |
|
8 |
28 |
30 |
35 |
36 |
15+ |
|
|
13 |
31 |
31 |
36 |
40 |
13+ |
|
|
Styx-7 680903-04 |
8 |
18 |
23 |
25 |
25 |
25 |
|
Sta. 1 (spec. 2) |
11 |
21 |
22 |
24 |
23 |
23 |
|
8 |
19 |
23 |
20 |
24 |
25 |
|
|
11 |
19 |
22 |
21 |
25 |
24 |
|
|
Styx-7 680907 |
7 |
28 |
35 |
36 |
34 |
35 |
|
Sta. 4 |
13 |
27 |
28 |
32 |
35 |
33 |
|
7 |
29 |
32 |
31 |
37 |
35 |
|
|
13 |
27 |
32 |
34 |
35 |
35 |
tt:, 4
:n 2
Dwarf males recovered from three large specimens; as many as 5-9 in a pouch on the inner sides of the scuta (Fig. 5G). They resemble those figured for S. eximium by Hoek (1883, pi. 9. fig. 10).
Remarks.— Tht Mid-Pacific specimens agree closely with Hoek's description of Scal- pellum eximium and the resemblance is particularly striking with regard to the character- istic shape of the dwarf males.
The specimens from the Mid-Pacific differ from the examples of Newman and Ross ( 197 1 ). The latter have a supramedian notch in the cutting edge of Maxilla I where as none is apparent in the present specimens; the intermediate segments of cirrus VI have 4 pairs of setae in Pacific specimens as opposed to 3 pairs in the North Atlantic individuals. The Elta-
80
nin specimens, which are relatively small, came from depths exceeding 3000 meters while the specimens from the Mid-Pacific were dredged at nearly half that depth and are large. However, while it is possible that allometry and bathymetry account for the observed differences, it is also possible that the differences are genetic. There are presently in- sufficient data to resolve this problem.
Arcoscalpellum radiatum n. sp.
Figure 6
A/a/ma/.-Styx-7, 680903 Sta. 1 Allison Guyot ( 179°36.0' W, 18°31.0'N), 1413-1645 m (otter trawl). 2 spec.
Depository.-V.S.NM. no. 140947 (Holotype. Styx-7. 680903 Sta. 1); U.S.N.M.no. 140948 (Paratype, Styx-7, 680903. Sta. 1).
Diagnosis.— Capitulum with 14 fully calcified approximate plates sculptured with prominent radial ribs emanating from the umbones. Carinal latera interdigitate at base of carina. Carinal roof flat, parietes well developed. Rostrum exposed, elongate triangular. Mandible with 4 teeth including a strongly denticulate inferior angle. Maxilla I with a deep medial notch in cutting edge. Caudal appendage uniarticulate and much shorter than first segment of pedicel of cirrus VI.
Description (female).— Capitulum elongate, oval, almost twice as long as broad; occlu- dent and carinal margins moderately arched, covered with long hairs; 14 fully calcified ap- proximate plates sculptured with prominent, evenly spaced ribs which extend from um- bones to basal margins; ribs intercepted by feeble lines of growth (Fig. 6A). Scutum subquadrate; twice as long as broad and broadest in the middle; occludent and carinal mar- gins subparallel, the latter % as long; surface slightly convex and traversed by ribs emanat- ing from region of umbo; ribs more conspicuous in lower half of plate; apical umbo partly overlapping occludent margin of tergum. Tergum triangular, sculptured with longitudinal ribs except for a narrow carinal portion. Upper latus appears triangular but is four sided; a faint diagonal angulation runs from umbo to carinolateral angle. Carina with broad base enclosed between carinal latera; roof flat and marked with broad 'U' shaped lines of growth; parietes well developed, smooth (Fig. 6B). Carinal latus higher than wide, lateral margin long and partly overlapped by inframedian latus; ribs radiate from umbo; while not shown in figure, carinal margins broadly interdigitating (Fig. 6B-C). Inframedian latus more than 4 times as long as broad; traversed by transverse striae; umbo at truncate apex. Rostral latus trapeziform; divided into two unequal triangular areas by a faint ridge that runs from umbo to basilateral angle. Rostrum well developed, triangular, broad above and pointed below (Fig. 6D). Peduncle short, covered with 6 rows of strong scales with pro- jecting edges.
Labrum bullate; crest armed with 21 V-shaped pointed teeth (Fig. 6H). Palp long and narrow; proximal superior and distal margins covered with spines (Fig. 61). Mandible with 4 teeth including the inferior angle; first tooth well separated from second (Fig. 6E); inferior angle strongly denticulate and armed with 8 pointed teeth (Fig. 6F). Maxilla I with a deep notch in middle of cutting edge; 2 long and 2 short spines above notch and 2 long and 2-3 short spines below notch; surface covered with long setae (Fig. 6G). Maxilla II triangular and covered with a few marginal setae on superior, distal and inferior margins.
Cirrus I separated from remaining cirri; posterior ramus slightly longer; segments moniliform; covered with long plumose setae (Fig. 6J). Cirrus II not modified. Cirri III-VI essentially equal in length with subequal rami. Articular areas along greater curvature with 1-2 long thin setae; interarticular areas and lateral faces naked; setation ctenopod; 2 major and 1 minor pair of setae along lesser curvature; a few short bristles at bases of these (Fig. 6K). Caudal appendage uniarticulate; shorter than first segment of pedicel of cirrus VI; an- terior and posterior borders free of setae; 4-5 setae distally. Cirral counts of the holotype follow:
I II III rv V VI Ca
|
Styx-7 680903 |
7 |
11 |
14 |
15 |
16 |
17 |
|
Sta. 1 (Holotype) |
8 7 |
12 12 |
13 14 |
15 15 |
16 15 |
16 15 |
|
8 |
10 |
14 |
14 |
16 |
17 |
7^ 1
81
O M V
|
,ltBCD |
2.0mm |
|
,EGHI |
1 n |
|
■ F |
05 |
|
JK |
OS
T^;^
Figure 6. Arcoscalpelliim radiatum n. sp., Holotype, Styx-7, 680903, Sta. I, Allison Guyot. A, side views of fe- male; B, carina! view; C, base of carina and abutment of carinal latera; D. rostrum and adjoining plates; E, mandible; F, third tooth and inferior angle of mandible; G, maxilla I; H, crest of labrum; I, palp; J, cirrus I; K, intermediate articles of cirrus VI.
Remarks.— Arcoscalpelliim radiatum is related most closely \o A. pacificum ( Pilsbry), A. c/2/7/eme(Pilsbry) (new name for A. ^raf/7<? (Pilsbry) and /I. semisculptum (Pilsbry). Charac- ters in common are an elongate capitulum, a narrow and elongate inframedian latus with an apical umbo and shorter than the carinal latus, the presence of a narrow and elongate rostrum and the possession of carinal latera which are higher than wide and interdigitating where they meet. The ornamentation of the capitular plates o{ A. radiatum recalls the con- dition in A. pacificum. However, the rostral latera of A. pacificum are wider than high, the
82
umbones of the carinal latera are at the lower '/4 of the carinal margin (Pilsbry, 1907a), the cutting edge of maxilla I is nearly straight and the caudal appendage is five-segmented (Annandale, 1913). Arcoscalpellum radiatum differs from A. pacificum in all these charac- ters. It differs from A. chiliense in the possession of longitudinal ribs on the terga and scuta, in the carinal roof being flat rather than convex, and in the inframedian latus which is pro- portionately much wider and decidedly higher than the adjoining rostral latus. Arcoscal- pellum semisculptum also has an inframedian latus which is much narrower than in A. radiatum, but in this species the umbones of the carinal latera are placed at the lower 'Z? of the carinal margin as opposed to their distinctly medial position in the new species. The type o^ A. semisculptum came from a depth of 512 meters which is nearly one-third the depth from which the Mid-Pacific specimens were taken. Broch ( 1953) recorded one speci- men from a depth of 1484 meters, comparable to the Pacific station. Unfortunately neither Pilsbry (1907c) nor Broch gave any details of the arthropodal structures of this species. Also present at the same station is a small individual which has not yet developed the radial sculpture, but is in all other respects similar to the one described above.
Arcoscalpellum rossi n. sp.
Figure 7
Ma/mfl/.-Styx-7, 680901 Sta. 3, Hess Guyot (174°24.8' W, 17°53.2'N), 1692-1735 m (Sigsbee beam trawl). 1 spec. Styx-7, 680903-04 Sta. 1, Allison Guyot (' 179°36.0' W, 18°31.0' N), 1413-1645 m (otter trawl), 2 spec.
Depositorv.-XJ.S.fiM.no. 140949 (Holotype, Styx-7, 680901, Sta. 1) U.S.N. M. no. 140950 (Paratypes, Styx-7, 680903-04 Sta. 1,2 spec).
Diagnosis (female).— Capitulum long and narrow, composed of 14 fully calcified plates. Roof of carina flat, parietes well developed, especially towards distal half of plate. Rostrum large, ovotriangular and fully exposed. Maxilla I with notch in middle of cutting edge. Mandible with four teeth including inferior angle; upper margin of third tooth ser- rated. Caudal appendage of 4 segments and reaching to ^4 height of first segment of pedicel of cirrus VI.
Description (female).— Capitulum long and narrow, composed of 14 fully calcified plates and sparsely covered with hairs. Plates separated by narrow chitinous interspaces and marked with faint lines of growth. Occludent margin strongly convex; carinal margin irregularly straight; apex slightly retroverted towards the carinal side (Fig. 7A).
Tergum triangular, occludent margin short and convex, scutal and basal margins al- most straight, carinal margin concave for % the distance towards the carinal angle and straight thereafter. Scutum more than twice as long as broad; lateral margin sinuate just below tergolateral angle; apex of upper latus projects towards this sinuous part; umbo api- cal, overlapping occludent margin of tergum. Upper latus appearing triangular but five sided. Carinal latus fully twice as long as broad; carinal margin curving out at base of ca- rina, beyond which umbones bluntly project. Carinal latera meet and surround base of ca- rina in form of a broad 'V and do not interdigitate (Fig. 7C). Carina long and simply bowed; roof flat; parietes well developed towards distal half of plate (Fig. 7B). Inframedian latus rectangular, more than four times as long as broad, umbo submedial in position, slightly displaced towards distal half and slightly raised above surface of plate. Rostral latus nearly rectangular in outline, with parallel but unequal scutal and basal margins and sub-parallel lateral margins. Rostrum large, fully exposed, elongate triangular, broad above and pointed below (Fig. 7D). Peduncle short, bent at right angles to capitulum and covered with 6-8 rows of narrow elongate plates with chitinous interspaces.
Labrum bullate; crest armed with 22 teeth. Palp narrow and elongate; superior and anterior margins armed with a few spines; inferior margin with proximal short stout spine (Fig. 7E). Maxilla I with a well defined notch in middle of cutting edge, 2 long and 1-2 short stout spines above and one long and 3-5 short spines below notch (Figs. 7H, I). Max- illa II with 3 well defined lobes; marginal setae long and setulose; setae distributed in 3 clusters, those of inferior margin being segregated; lateral margins sparsely setose; max- illary lobe moderately long and cylindrical (Fig. 7J). Mandible with 4 teeth including infe- rior angle; second tooth twice the distance from the first than from the third tooth; upper margin of third tooth serrate (Fig. 7F); inferior angle supporting 8 long, narrow and pointed teeth (Fig. 7G).
83
|
.AC |
2.0 |
|
|
2.0 |
1.0 |
|
|
0.2 |
||
|
,FI) |
||
|
,eH |
0.1 |
|
|
0-5 |
0.2
05
Figure 7. Arcoscalpellum rossi n. sp., Holotype, Styx-7. 680901, Sta. 3, Hess Guyot. A, right side view of female; B, carina! view; C, carinal latera; D, rostrum; E, crest of labrum and left palp; F. mandible; G. third tooth and inferior angle of mandible; H-I, maxillae I; J. maxilla II; K, intermediate articles of cirrus VI; L, cirrus I; M, caudal appendage.
Cirrus I (Fig. 7L) separated from the rest: cirrus II normal; articular areas along greater curvature of cirrus VI with one sharp spine; interarticular areas faintly serrated with 5-6 spines; lateral faces devoid of setae. Setation ctenopod; 2 major and 1 minor pair along
84
lesser curvature. Caudal appendage composed of 4 segments; reaching to % length of first segment of pedicel of cirrus VI; distal segment with 2 long and 1 short setae (Fig. 7M). Cir- ral counts follow:
I II III IV V VI Ca
|
Styx-7, 680901 |
7 |
12 |
15 |
18 |
18 |
18 |
|
Sta. 3 |
8 |
13 |
18 |
18 |
19 |
19 |
|
(Holotype) |
1 + |
12 |
17 |
19 |
19 |
20 |
|
8 |
14 |
15 |
17 |
19 |
18+ |
tt: 4
Remarks.— Arcoscalpellum rossi is related ioA.flavum (Hoek, 1883: 127), yl. novae-Zea- landeae {Hoek, 1883: 124),^. a^v^^/co/a (Hoek, 1883:114),/J. m/>7w/wm (Hoek, 1883:113),^!. perlongum (Pilsbry, 1907b: 198), A. albatrossianum (Pilsbry, 1907c:54). Characters that unite all these species are: 1) the capitulum is elongate and narrow, the lower whorl of latera contributing in part to its lengthening; 2) a long and narrow inframedian latus with an umbo that is medial to basal.
With the exception o^ A. rossi all these species have an inframedian latus which is ei- ther hour-glass shaped or has at least a narrow constriction in the middle. Arcoscalpellum rossi can be separated readily from these by its rectangular inframedian latus which is not at all constricted. Further, it has a well developed rostrum that is fully exposed whereas in the others a rostrum has not been described or, if present, is of a smaller size.
In the relative proportions of the capitular plates and in the general nature of the ar- thropodal structures A. rossi shows a close resemblance to A. albatrossianum and A. per- longum. All three species have a mandible in which the upper margin of the third tooth is serrate and maxilla I has a deep notch in the middle of the cutting edge (Nilsson-Cantell, 1925; MacDonald, 1929). However, in A. albatrossianum and A. perlongum the caudal ap- pendages reach beyond the pedicel of cirrus VI and respectively have 8 and 6 segments whereas in A. rossi the caudal appendage is shorter than the first segment of the pedicel of cirrus VI and has 4 segments.
The species is named for Arnold Ross, Natural History Museum, San Diego, student of barnacles, and friend.
1 Arcoscalpellum sp. Figure 1 lE-F
Material.-Sly\-1, 680910 Sta. 5. Sio Guyot (171°05.r E, 18°17.7 N). 1692 m (pipe dredge), broken shells.
The shell fragments from Sio Guyot, while undoubtedly belonging to a scalpellid, are too incomplete to allow positive identification and are tentatively assigned to Arcoscal- pellum on the basis of a carina (Fig. 1 IF) and a scutum (Fig. 1 IE).
Genus Mesoscalpellum Hoek, 1907
Mesoscalpellum gruvelii (Annandale), 1906
Figures 8 and 1 IH-I
Scalpellum gruvelii Annandale 1906b:390; 1906a: 141, text-fig. 4; 1907-1908, pi. 1, fig. 1. pi. 11, figs. 1, la, 3; 1913:232; Scalpellum gruvelii var. quadralum Annandale, 1906b:391; 1907, pi. II, fig. 3: Annandaleum gruvelii; Newman and Ross, 1971 : 122; Scalpellum chitinosum Hoek. 1907:73 pl. VII, fig. 4; Scalpellum imperfectum Pilsbry, 1907c:75. pl. IV, figs. 15-18, text-fig. 30; Barnard, 1924:46; 1925:3; MacDonald, 1929:537, pl. 2, fig. 3; Broch, 1953:9; Stubbings, 1961:11, fig. 2; Zevina; 1969:67; Mesoscalpellum imperfectum: Newman and Ross, 1971:119; fig. 62.
Malerial.~Slyx-l. 680903-04 Sta. 1. Allison Guyot ( 179°36.0' W, 18°31.0' N), 1429-1663 m (otter trawl), 1 spec; 680905, Allison Guyot ( 179°37.r W, 18°35.4' N), 1449-1557 m (otter trawl), several spec.
Supplementary description (female).— There is considerable variation in the external morphology of the large series of specimens from the Mid-Pacific (see fig. 8A-C, 1 IH-I). However, specimens comparable in size to Annandale's types appear identical with his de- scriptions. Some clarification is needed as regards the vase-shaped nature of the in- framedian latus, supposedly characteristic of the genus Annandaleum (Newman and Ross, 1971). In A. gruvelii, both in the original description and in several of the specimens in the present collection the outline of this plate has the shape of an hourglass. A club-shaped ridge, with its expanded extremity, projects outwards, and it is this ridge that gives the plate its vase-like appearance, especially when seen through the semi-transparent membrane.
85
.^>>%.-^
|
,*c |
|
|
,B |
4n |
|
,D |
in |
|
,EN |
in |
|
JIIM |
ni |
|
,Sl |
ns |
|
,H |
D1 |
|
,R 7 |
2.0
Figure 8. Mesoscalpellum gruvelii (Annandale), Styx-7, 680903-04 Sta. 1, Allison Guyot (A and D-N); Styx-7, 680905, Sta. 2. Allison Guvot (B-C). A-C, side views of females; D, male cyprid; E. crest of labrum; F, palp: G, mandible; H, third tooth and inferior angle of mandible; I. maxilla I; J, maxilla II; K, cirrus I; L. intermediate article of outer ramus of cirrus VI; M, intermediate article of inner ramus of cirrus VI; N, caudal appendage.
The bearing this problem has on the distribution of the genus will be taken up below, under remarks.
Annandale's descriptions of mouth parts and cirri are incomplete and are elaborated on as follows. Labrum long, triangular rather than buUate; crest armed with 40-50 bluntly
86
pointed teeth (Fig. 8E). Palp elongate, bluntly triangular distally; superior proximal margin with a few stout spines; distal extremity strongly spinose, lateral faces with a few spines (Fig. 8F). Maxilla I with straight cutting edge; upper margin with 1 short and,2 long spines; lower margin supporting 2 long and 4 short, stout spines (Fig. 81). Mandible with 4 teeth including a slightly receding inferior angle; first tooth well separated from second; third tooth proximal to inferior angle (Fig. 8G); inferior angle supporting 12-13 moderately long, somewhat pointed teeth (Fig. 8H). Maxilla II triangular, lobes feebly developed; marginal setae distributed in 3 clusters; lateral faces setose; maxillary lobe elongate, broad near the base and narrow apically (Fig. 8J).
The cirri, as noted by Annandale, are devoid of pigment. Cirrus I widely separated from the rest; intermediate segments of anterior ramus protuberant, those of posterior ramus cyhndrical and Va as wide (Fig. 8K). Cirri II-VI increasing progressively in length and with equal or subequal rami. Greater curvatures of cirri II-VI with 2-3 rows of stiff bristles; lateral faces with 1-4 rows of setae; articular areas with a cluster of 3-5 setae; interarticular areas with 1-4 setae. Distal cluster of setae along lesser curvature of intermediate segments hypolasiopod in outer ramus and ctenopod (3 major pairs and I minor pair) in inner ramus; 2-3 pairs at bases of all major setae (Figs. 8L, M). Caudal appendages as long as pedicels of cirrus VI; each consisting of 8 segments; distal segment supporting 6 long setae of equal length (Fig. 8N). Cirral counts of one specimen are:
I II III IV V VI Ca
|
Styx-7, 680903-04 Sta. 1 |
8 11 |
19 22 |
23 24 |
27 28 |
28 26 |
30 28 |
|
8 |
20 |
24 |
26 |
28 |
29 |
|
|
10 |
22 |
26 |
26 |
28 |
29 |
A male cyprid was found in a pouch on the inner side of the right scutum of one speci- men. It resembles (Fig. 8D) the male cyprid of 5". gruvelii ( = M. gruvelii) by Stewart (1911).
Remarks.—Several authors expressed concern over the similarities between Annanda- leiim gruvelii (Annandale), Mesoscalpellum imperfectum (Pilsbry), and M. sanctaebarbarae (Pilsbry), (see Pilsbry 1907c; Annandale, 1913; Barnard, 1924; Stubbings, 1961; Newman and Ross, 1971). This and related problems need clarification here. The first is with regard to the inclusion of gruvelii, in the genus Annandaleum proposed by Newman and Ross (1971) for the reception of this and three other Indo-West Pacific species. The most diagnos- tic characteristic of Annandaleum is the large and vase-shaped inframedian latus, which as far as can be judged from published figures, is present in A. japonicum, A. lambda and A. flavum. In A. gruvelii, it is not well developed and the inclusion of this species '\n Annanda- leum greatly weakens the definition of this genus. Actually /I. gruvelii has a facies similarity with members of the genus Mesoscalpellum and we propose that it be transferred to this genus. This greatly sharpens the distinction between the two genera.
The second problem concerns M. gruvelii and M. imperfectum. Several specimens from the Mid-Pacific collection show a point to point similarity with the description of M. gruvelii (Annandale, 1906b) and there is no doubt that the specimens before us belong to this spe- cies. However, the arthropodal structures of the Mid-Pacific specimens are almost identical with those of the paratypes of M. imperfectum figured by Newman and Ross (1971, text-fig. 62). Therefore we believe that imperfectum and gruvelii are the same species, a synonymy that has been suggested before.
This leaves us the question as to the status of M. sanctaebarbarae. Newman and Ross pointed out several diff'erences in the anatomy of A/, imperfectum ( = M. gruvelii) and M. sanctaebarbarae. We have had the opportunity to examine closely the soft parts of the latter species from the San Diego Trough, which confirm that the diff'erences are consistent, with one exception. The setation of the distal cluster of the intermediate articles of the outer rami of cirrus VI is said to be ctenopod in the paratypes whereas it is distinctly hypolasio- pod in the specimen from the San Diego Trough. The importance of this diff'erence remains to be determined and in the light of other dilTerences we are inclined to continue to recog- nize the two species.
87
With the transfer of gruvelii to Mesoscalpellum and the recognition of A/, imperfectum as a synonym of M. gruvelii, the genus and the species take on a world wide distribution (Indian, Atlantic and Pacific oceans).
Family Poecilasmatidae Annandale, 1909
Genus Megalasma Pilsbry, 1907c
Subgenus Glyptelasma Pilsbry, 1907c
Megalasma (Glvptelasma) pilsbryi Caiman, 1919
Figure 9
Megalasma (Glvptelasma) pilsbryi Caiman, 1919:363. fig. lA-C. fig. 2; Nilsson-Cantell, 1928:20, fig. 9A-E; 1938:10.
MaleriaL^Sxy\-l. 680905 Sta. 2, Allison Guyot ( 179°37.r W. 18°35.4' N), 1445-1557 m (otter trawl). 10 spec, all attached to Anoscalpellum michelollianum and Mesoscalpellum gruvelii..
5'i//7/7/£'me/7/arvfife5cr//7//6>n.— The external morphology ofour Specimens agrees with the description given by Caiman (1919). The base of the carina is produced into two teeth on the inner side (Fig. 9C). In the present specimens the basal margin of the scutum and carina meet at an angle of more than 90° whereas in Caiman's specimens these are shown to meet at right angles. This character varies with growth.
Nilsson-Cantell (1928) gave brief descriptions of the mouth parts. More detail of the trophi and cirri is in order. Labrum buUate, slightly broader than long and bluntly triangu- lar anteriorly; anterior margin and surface covered with tufts of 2-6 fine, short hairs; crest armed with 35 small, stout and somewhat pointed teeth (Fig. 9F). Palp broad proximally and bluntly conical distally; superior margin free of setae; inferior and distal margins bor- dered by long plumose setae; lateral faces setose (Fig. 9F). Mandible with 5 teeth including inferior angle; upper margin of fourth tooth serrate; surface profusely covered with long thin spinules some of which cross the cutting edge; superior and inferior margins bordered by short, thin hairs along the entire length (Fig. 9G); inferior angle tridentate, the teeth being short and pointed (Fig. 9H). Maxilla I with cutting edge concave above and strongly convex below, without a well defined notch, 2 long and 1 short spine above; the convex lower portion supports a set of 14-15 short and long spines, and superior and inferior mar- gins as well as surface covered with short hairs (Fig. 91). Maxilla II triangular, higher than wide; superior lobe well developed, distal and inferior lobes feebly so; marginal setae dis- tributed in three clusters, those of superior and distal lobes separated by a naked superior margin (Fig. 9J).
Cirrus I widely separated from cirrus II; anterior and posterior rami equal in length and composed of 9 and 10 segments respectively; segments of anterior ramus l'/4-iy2 times broader than those of posterior (Fig. 9E). Cirrus II, Wi times longer than cirrus I; cirri III- VI equal in length with equal rami and composed of a rather constant number of segments. Articular areas along greater curvatures with 2-3 long and 1-2 short setae; interarticular areas and lateral faces devoid of setae; setation ctenopod; 3 major pairs and 1 minor pair along lesser curvature; 1-3 short bristles at bases of major pairs (Fig. 9K). Caudal appen- dage uniarticulate, short, about Vy height of first segment of pedicel of cirrus VI; anterior and posterior margins bordered with small and inconspicuous spinules; distal end broad, with 8 short to long plumose setae (Fig. 9L). Penis large, proximally broad, gradually taper- ing to a blunt apex; surface covered with long thin setae which are sparsely distributed for a greater length of the organ but are more profuse and conspicuous towards the distal end. A single pair of rather short, slender filamentary appendages are present on dorsum of pro- soma near its posterior margin (Fig. 9M), as described and figured by Caiman (1919). Cirral counts of the dissected specimen follow;
I II III IV V VI Ca
|
Styx-7, 680905 |
9 |
15 |
19 |
18 |
19 |
19 |
|
Sta. 2 |
10 |
16 |
19 |
19 |
19 |
20 |
|
9 |
17 |
19 |
19 |
19 |
20 |
|
|
10 |
16 |
19 |
19 |
19 |
18 |
88
|
<AD |
50 |
|
|
|B |
10 |
|
|
.CM |
2 0 |
|
|
,E |
05 |
|
|
iFGIJKL |
0 |
|
|
,H |
02 |
Figure 9. Me^alasma (Glvptelasma) pilsbryi Caiman, Styx-7, 680905, Sta. 2, Allison Guyot. A-B, right side view of hermaphrodites; C, inner view of disarticulated shells; D, outer view of carina; E, cirrus I; F, labrum and palps; G. mandible; H, third and fourth teeth and inferior angle of mandible; I, maxilla I; J, maxilla II; K, intermediate articles of cirrus VI; L, caudal appendage; M, prosoma and filamentary appendages.
Remarks.— ?'\hhxy ( 1 907c,d) and Caiman (1918b, 1919) discussed the status and defini- tions of the genus Megalasma and its subgenera Megalasma s.s. and Glvptelasma. The speci- mens from the Mid-Pacific are clearly referable to Glvptelasma because the basal margin of
89
the scutum forms a distinct angle with the occludent margin, and also by the weak sculpture of the plates. The configuration and relative proportions of the capitular plates and the gen- eral structure of the trophi and cirri are in agreement with the description of Megalasma (Glvptelasma) pilsbrvi. The bathymetry is also similar. The figures and descriptions given by Nilsson-Cantell show that the crest of the labrum has about 50 teeth, the rami of cirrus I have 9 and 1 1 segments and the posterior cirri have 23-24 segments. In contrast, the crest of the labrum of the Mid-Pacific specimen supports 35 teeth, the rami of cirrus I have 9 and 10 segments respectively and the posterior cirri are composed of 18-20 segments. It is likely that allometry may account for these differences, Nilsson-Cantell's specimens being larger (capitular height: 20 mm) than the Mid-Pacific example (capitular height: 1 1 mm).
Megalasma pilsbrvi is closely related to M. annandalei Pilsbry. Caiman (1919) and Barnard (1925) recognized this, but both authors advocated their retention as good species. Caiman stated that A/, pilsbrvi diflfers from M. annandalei "in having no sudden widening of the sides of the carina and no excavation of the adjacent sides of the scutum, as well as in the thick cuticle covering the valves ..." Furthermore the intermediate segments of cirrus VI of M. pilsbrvi support 3 major pairs and one minor pair of setae along the lesser curvature whereas in M. annandalei there are 4 major pairs and 1 minor pair (Pilsbry, 1907, pi. V, Fig. 14).
The Mid-Pacific specimens were found attached to Arcoscalpellum michelottianum and Mesoscalpellum gruvelii. Nilsson-Cantell (1928) collected this species from Scalpellum ve- lutinum ( = A. michelottianum) and S. alcockianum ( = A. alcockianum).
Suborder Verrucomorpha Pilsbry, 1916
Family Verrucidae Darwin, 1854
Genus Verruca Schumacher, 1817
Subgenus /I ///vernvcfl Pilsbry, 1916
Verruca (Altlverruca) allisoni n. sp.
Figure 10
Material.-Sty\-1, 680901, Hess Guyot (174°24.8' W, 17°53.2' N), 1,718-1,770 m (Sigsbee beam trawl), 3 spec, on trochid gastropods: Styx-7 680915 Sta. 1. Darwin Guyot, (171°16.5' E. 21°53.3' N), 1.300-1.353 m (rock dredge), 2 spec, on manganese fragment.
De'/70.5//o/;v.-HolotypeU.S.N.M.no. 140951 (Styx-7, 6809 15); Paratypes U.S.N. M. no. 140952 (Styx-7, 680901).
Z)/ag«o5/5.— Distinguished from all other A Itiverruca in having 7 rather than 3 or 4 in- terlocking teeth forming the suture between the carina and rostrum.
Description.—ShQll white, without persistent yellow cuticle. Suture between rostrum and carina formed by numerous interdigitating ribs (Fig. lOH). It can be deduced from successive growth lines that the number of ribs increases throughout life. In the holotype this number has increased from as few as 3 or 4 to 7. Sutures formed by rostrum overlap- ping fixed scutum and by carina overlapping fixed tergum; sutures simple except carinal margin of fixed tergum is ala-like. Suture between fixed tergum and fixed scutum formed by an ala-like margin on former and radius-like margin on latter (Fig. lOG). Parietal por- tion of fixed tergum interdigitates between radius-like and parietal portions of fixed scutum.
Movable tergum and scutum articulated by the interdigitation of proximal portions of their apico-basal ridges (Fig. lOH). Supplemental ridges parallel main ridges on scutal side of the movable tergum, and the rostral portion of the movable scutum is ornamented by longitudinal lines (Figs. lOK, L).
Crest of labrum supports numerous teeth, nearly 80 in the paratype; palps pointed, sparsely covered with short strong setae (Fig. lOA). Mandible with 3 teeth, not including lower cutting edge and inferior angle; upper margin of third tooth and lower cutting edge serrate; inferior angle of several stout spines (Fig. lOB). First maxilla with group of long strong spines above and below well developed notch; inferior angle supporting few short, bifid spines (Fig. IOC). Second maxilla notched and sparsely covered with setae (Fig. lOD).
Second cirri resemble more the first than the succeeding pairs. Their rami are rela- tively short, subequal and uncoiled. Intermediate articles of posterior pairs ctenopod, each supporting 1 long plumose and 1 short simple pair of setae, and often 1 minute simple seta, along the lesser curvature (Fig. lOF). Caudal appendages of 6 to 8 segments and less than
90
Figure 10. Verruca (Altiverruca) allisoni n. sp. A-F and I-L, Holotype. A, labrum and palp, left palp removed; B, mandible; C, maxilla I; D, maxilla II; E, pedicle of cirrus VI supporting penis and caudal appendage; F, inter- mediate article of cirrus VI; G, lateral view of entire specimen illustrating relationship of carina, fixed tergum and fixed scutum; H, lateral view of entire specimen illustrating relationship of movable terga and scuta with the carina and rostrum; I and L, interior and exterior views of the movable scutum respectively; J and K, interior and exterior views of the movable tergum respectively.
91
Figure 1 1. A. Arcoscalpellum michelottianum (Seguenza), carinal view of female X 1.42; B, right side view of the same individual X 1.6; C, A. hawaiiense (Pilsbry), right side view of female X 1.7; D, carinal view of the same individual X 1.4; E, ? Arcoscalpellum sp. scutum X 4.2; F. ? Arcoscalpellum sp., carina X 3.4; G, A. alcockianum (Annandale). right side view of hermaphrodite X 1.57; H, Mesoscalpellum gruvelii (Anr\2LX\da.\t), rightside view of female X 1.4; Mesoscalpellum gruvelii (Annandale), right side view of female X 3.9 (A-D and H from Styx-7, 680905 Sta. 2, Allison Guyot; E-F from Styx-7, 680910 Sta. 5, Sio Guyot; G and I from Styx-7, 680903-04 Sta. 1, Allison Guyot).
92
the length of the basal segment of the pedicel of cirrus VI; the penis relatively short, pro- vided distally with a few short seta (Fig. lOE). Cirral counts for three specimens follow:
I II III IV V VI *
|
Hess Guyot Styx-7, 680901 (Paratype) |
9 8 |
7 8 |
13 16 |
22 23 |
22 |
24 26 |
|
Hess Guyot Styx-7. 680901 (Paratype) |
11 9 |
9 11 |
13 16 |
17 21 |
20 15 |
17 19 |
|
Darwin Guyot Styx-7, 680915 Sta. 7 ( Paratype ) |
6 6 |
9 10 |
13 14 |
17 16 |
17 |
19 |
Remarks. — Verruca (Altiverruca) allisoni is similar to V. (A.) cristallina Gruvel, 1907 from the East Indies, V. (A.) gibbosa Hoek, 1883 which is nearly cosmopolitan, and V. (A.) regularis Nilsson-Cantell 1929 from the Nicobar Islands. It differs from the first in having 7 rather than 3 or 4 interlocking teeth between the rostrum and carina, in lacking multiple interlocking ridges between the suture of the fixed tergum and scutum and in lacking the small beaded ridges along the scutal margin of the rostrum. It differs from the second and third in having 7 rather than 4 interlocking teeth between the rostrum and the carina, in having the movable scutum with longitudinal markings and in having a fixed scutum lack- ing an ala-like rostral margin.
The major difference between this and other species of Altiverruca is the large number of interlocking teeth between the rostrum and carina. In fact this same difference separates this species from all other Verruca except V. (?Rostratoverruca) dens Broch 1931, V. (R.) intexta Pilsbry 1912, V. (?R.) koehleri Gruvel 1907, V. (?R.) nexa Darwin 1854 and V. (Ver- ruca) scrippsae Zullo 1964. Broch's illustration indicates there are about 6 interlocking teeth between the rostrum and carina, essentially as in the present species. Pilsbr)' (1907c), dis- cussing Darwin's species, says that there are 7 ribs on the carina interlocking with the ros- trum. It is curious that the ne'w Altiverruca should be so similar in this regard to these mem- bers of Rostratoverruca. One might suspect that the subgeneric diagnosis was wrong. However there is no question that the apex of the rostrum is not separated from the scutal margin of the plate, as it is in Rostratoverruca. The similarity to V. (V) scrippsae is only with regard to the carino-rostral suture; the complex interlocking sutures between the fixed scu- tum and the rostrum and the fixed tergum and the carina are wholly lacking in V. (A.) alii-' soni.
ACKNOWLEDGMENTS,
This paper is a contribution from the Scripps Institution of Oceanography and was supported in part by National Science Foundation grants GB-7596 and GB-30908X.
LITERATURE CITED
Allison, E.C., J.W. Durham, and L.W. Mintz
1967. New Southeast Pacific Echinoids. California Acad. Sci. Occ. Pap. 62: 1-23. Annandale, N.
1905. Malaysian barnacles in the Indian Museum, with a list of the Indian Pedunculata. Mem. Asiatic Soc. Bengal. 1(5): 73-84.
1906a. On the Cirripedia. Rept. Pearl Oyster Fisheries, Govt. Ceylon 5(31): 137-150.
1906b. Natural History Notes from the R.l.M.S. ship "Investigator." Ser. 111. No. 12. Preliminary report on the Indian stalked barnacles. Ann. Mag. Nat. Hist. 7(17): 389-400.
1907-1908. Illustrations of the Zoology of the R.l.M.S. ship "Investigator." Crustacea (Entomostraca), pis. I- IV.
1909. An account of the Indian Cirripedia Pedunculata. Part I. Family Lepadidae (sensu stricto). Mem. In- dian Mus. 2: 61-137.
1913. The Indian barnacles of the subgenus Scalpellum. Rec. Indian Mus. 9(4): 229-236.
1916. Three plates to illustrate the Scalpellidae and Iblidae of Indian Seas, with synonymy and notes. Mem. Indian Mus. 6(3): 127-131.
93
Barnard, K.H.
1924. Contribution to the crustacean fauna of South Africa. No. 7 Cirripedia. Ann. South African Mus. 20: 1-103.
1925. Report on a collection of Cirripedia from South African waters. Rept. Fish. Mar. Biol. Survey IV(6), Cape Town: 1-5
Broch, H.J.
1931. Indomalayan Cirripedia. Papers from Dr. Th. Mortenson's Pacific Expedition. 1914-1916. Vidensk.
Meddel. Dansk Naturh. Foren. 91: 1-146. 1953. Cirripedia Thoracica. Danish-IngolfExped. 3(14): 1-17. Caiman. W.T.
1918a. On barnacles of the genus Scalpellum from deep-sea telegraph cables. Ann. Mag. Nat. Hist. 9(1): 96-
124. 1918b. The type specimens of Poecilasma carinatum Hoek. Ann. Mag. Nat. Hist. 9(4): 401-408. 1919. On barnacles of the genus Megalasma from deep-sea telegram cables. Ann. Mag. Nat. Hist. 9(24): 361- 374. Darwin, C.
1854. A monograph on the subclass Cirripedia, with figures of all the species. The Balanidae, the Verrucidae etc. Ray Soc, London. 684 p. Gruvel, A.
1907. Cirrhipedes opercules de le 1' Indian Museum de Calcutta. Mem. Asiatic Soc. Bengal. 2(1): 1-10. Hamilton, E.L.
1956. Sunken Islands of the Mid-Pacific Mountains. Geol. Soc. America Mem. 64: 1-97. Hoek, P.P.C.
1883. ReportoftheCirripediacollectedbyH. M.S. Challenger during the years 1873-1876. Rept. Scient. Res.
Voyage H.M.S. Challenger, Zool. 8 (4): 1-169. 1907. The Cirripedia of the Siboga Expedition. Cirripedia Pedunculata. Siboga Expedite. 31a. 1-127. Hubbs, C.L.
1959. Initial discoveries of fish faunas on seamounts and offshore banks in the Eastern Pacific. Pacific Sci. 13(4): 311-316. Karig, D.E., M.N. A. Peterson and G.G. Shor
1970. Sediment-capped guyots in the Mid-Pacific Mountains. Deep-Sea Research 17: 373-378. Lonsdale, P.F.. W.R. Normark and W. A. Newman.
1972. Sedimentation and erosion on Horizon Guyot. Geol. Soc. America Bull. 83: 289-315. Menard, H.W.
1964. Marine Geology of the Pacific. McGraw Hill Co., New York. MacDonald, R.
1929. A report on some cirripedes collected by the S.S. Albatross in the eastern Pacific during 1891-1904. Bull. Mus. Comp. Zool. Harvard 49( 15): 527-538. Newman, W.A. and A. Ross.
1971. Antarctic Cirripedia. Antarctic Research Series 14: 1-257. Amer. Geophys. Union. Nilsson-Cantell, C.A.
1925. Neue und wenig bekannte Cirripeden aus den Museen zu Stockholm und zu Uppsala. Ark. Zool. 18 A(3): 1-46.
1928. Studies on Cirripedes in the British Museum (Natural History). Ann. Mag. Nat. Hist. 10(2): 1-39.
1929. Cirripedien des Genus Verruca der Deutschen Tiefsee-Expedition auf dem Dampfer "Valdivia" 1898- 1899. Zool. Jahrb. Syst. 58: 459-480.
1931. Cirripedes from the Indian Ocean and Malay Archipelago in the British Museum (Natural History),
London. Ark. Zool. 23 A(18): 1-12. 1938. Cirripedes from the Indian Ocean in the collection of the Indian Museum, Calcutta. Mem. Indian
Mus. 13(1): 1-81. Pilsbry, H.A.
1907a. Hawaiian Cirripedia. Bull. U.S. Bureau Fish. 26: 181-190.
1907b. Cirripedia from the Pacific Coast of North America. Bull. U.S. Bureau Fish. 26: 193-204.
1907c. The barnacles (Cirripedia) contained in the collections of the U.S. National Museum. U.S. Natl. Mus.
Bull. 60: 1-122. 1907d. Notes on the cirriped genus Megalasma. Proc. Acad. Nat. Sci. Philadelphia 59: 408-416.
1911. Barnacles of Japan and Bering Sea. Bull. U.S. Bureau of Fish. 29: 59-84.
1912. Diagnoses of new barnacles from Philippine Archipelago and China Sea. Proc. U.S. Natl. Mus. 42: 291-294.
1916. The sessile barnacles (Cirripedia) contained in the collections of the U.S. National Museum, including a monograph of the American species. U.S. Natl. Mus. Bull. 93: 1-366. Schumacher, C.F.
1817. Essai d'un nouveau Systeme des habitations des Vers testaces. Schultz, Copenhagen. Seguenza, G.
1873-1876. Ricerche palaentologiche intorno ai Cirripedi Terziarii della provincia di Messina. Con appen- dice intorno ai Cirripedi viventi nel Mediterraneo, e sui fossili terziarii dell "Italia meridionale. Pt. 1, Balanidi e Verrucidi, 1873: Pt. II, Lepadidi, 1876. Atti Accad. Pontaniana, Napoli. 10: 265-481. Stewart, F.H.
94
1911. Studies in postlarval development and minute anatomy in the genera Scalpellum and Ibla. Mem. In- dian Mus. 3(2): 33-51. Stubbings, H.G.
1961. Cirripedia from the Tropical West Africa. Atlantide Rept. 6: 7-41. "
Zevina, G.B.
1969. Cirripedia Thoracica. The Biology of the Pacific Ocean, book II pt. I, Deep-Sea Bottom Fauna, V.G. Kort. ed., Inst. Okeanol. Akad. Sci. U.S.S.R.: 66-68.
1972. Benthic Lepadomorpha (Cirripedia Thoracica) from the Southeast Pacific. Crustaceana 22( 1): 39-63. Zullo, V.A. R.F. Kaar, J.W. Durham and E.C. Allison.
1964. The echinoid genus Salenia in the Eastern Pacific. Palaeont. 7(2): 331-349. Zullo, V.A. and W.A. Newman.
1964. Thoracic Cirripedia from a Southeast Pacific Guyot. Pacific Sci. 18(4): 355-372.
Scripps Institution of Oceanography, LaJolla, California 92037
sa^ ^6/r
MUS. COMF. ZOOi:. LIBRARY
DEC 71976
HARVARD
A NEW MITRID FROM THE WESTERN ATLANTIC
GEORGE E. RADWIN AND LOYAL J. BIBBEY
TRANSACTIONS
OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
VOL. 17, NO. 7 31 AUGUST 1972
A NEW MITRID FROM THE WESTERN ATLANTIC
GEORGE E. RADWIN AND LOYAL J. BIBBEY
ABSTRACT.— Mitra helenae n. sp. from Cay Sal Bank, between the Florida Keys and Cuba, is assigned to the subgenus Pleioptvgma Conrad, 1863, which was previously known to contain only species of Miocene and Pliocene age. The large size of this gastropod, its distinctive clouded color pattern and its threaded sculpture are unique among Recent western Atlantic mitrids. Although assigned to the Mitridae, the true familial affin- ities oi Pleioptvgma and this new species must await study of the radular dentition.
Malacology has long benefitted from the cooperation of commercial fishermen whose constant searching of the ocean for the objects of their commerce has led them to discover many new forms of marine life.
Recently, through the kindness of Mr. Ivan Thompson of El Cajon, California, we ex- amined two specimens of a remarkable and apparently undescribed mitrid. Mr. Thompson received these gastropods from Captain Jack Casey of Marathon, Florida, who reported collecting them in lobster pots set at a depth of 2 1 .5 m on Cay Sal Bank, between the Florida Keys and Cuba, in December, 1971. Both shells were inhabited by hermit crabs whose well- known carnivorous and scavenging feeding habits almost certainly account for their pres- ence in the pots.
Family Mitridae Swainson, 1831
Genus Mitra Lamarck, 1798
Subgenus Pleioptvgma Conrad, 1863
Type species. — Valuta carolinensis Conrad, 1840, by monotypy; Miocene; North Caro- lina.
Definition.— ^hoW large, up to 125 mm in length, fusiform, elongate, inflated, and mod- erately light in weight; protoconch of 2 or IVi smooth whorls, teloconch of 6 to 8 slightly convex whorls. Sculpture consisting of moderate to very sharp spiral threads or cords, spaced irregularly and becoming obsolete medially on the whorl. Aperture elongate, slightly longer than spire, smooth within, lip edge thin, with or without a slight swelling anteriorly just below the shoulder slope on the inner surface of the lip; columella with 6-9 irregular, moderately thin, simple folds. Siphonal notch weak to moderately strong; a thin columellar callus extends along the entire inner margin. (Modified after Cernohorsky, 1970:60).
/^ema/'A.y.— Cernohorsky (1970) indicated that Pleioptvgma probably belongs in the Volutidae. He based his opinion on "large size, inflated and light shell, large columellar cal- lus, absence of a siphonal notch and thin, irregular, often intercalate columellar folds."
We disagree with this placement for several reasons, but primarily as a result of our examination of two Recent specimens of a species referable to Pleioptvgma. It seems to us that the extremely diverse nature of mitrid and volutid shell form greatly weakens Cerno- horsky's arguments. Although volutids average larger than mitrids, the existence of such species as Mitra swainsoni, M. belcheri and M. mitra, all of which reach 120- 150mm, clearly shows the potential for large size in this family. Cernohorsky's other arguments are equally difficult to accept as criteria for excluding Pleioptvgma from the Mitridae. A siphonal notch is apparent on our specimens of the type species and on our new species. Irregularities in the plication and extent of callus development are certainly no greater here than in Dibaphus Philippi, 1847, an unquestioned mitrid with no plaits or callus.
Our contention for a mitrid assignment is based on the general form of the shell and, in particular, on the unusual clouded color pattern and the threaded sculpture. Also, the pro- toconchs of both fossil and Recent species (Figs. 7, 8) are different from any known type of volutid protoconch (see Pilsbry and Olsson, 1954). We are thus tentatively placing the sub- genus Pleioptvgma in the Mitridae, pending examination of the radular dentition of A/. (P.)
SAN DIEGO SOC. NAT. HIST.. TRANS. 17 (7): 95-100, 31 AUGUST 1972
96
helenae.
As Cernohorsky noted, no Recent representatives have been found.
Mitra (Pleioptygma) helenae n. sp.
Type locality.— Cay Sal Bank (between the Florida Keys and Cuba), ca. 23°45'N., 80°20''W., 21.5 m. Captain Jack Casey coll., December, 1971 (holotype: Figs. 2, 5).
Type depository.— Hololype, San Diego Soc. Nat. Hist., Mar. Invert, no. 61863; para- type, collection of Ivan Thompson.
Diagnosis.— Mitra helenae is comparable to two fossil species from the southeastern United States. It is similar in size and shape to M. carolinensis (Conrad, 1840), a species that is probably identical to M. heilprini Cossmann, 1899 ( = A/. lineolata Heilprin, 1887, not Bellardi, 1885). It differs from M. carolinensis in its more poorly marked columellar callus, its less sharp-crested more closely spaced spiral threads, its broader more inflated penulti- mate nuclear whorl, its more strongly impressed suture, its more apparent siphonal fasciole, its slopingly shouldered body whorl and its possession of small intermediate plaits between the anterior columellar plaits.
The other fossil species, M. prodroma Gardner, is probably the ancestor of A/, heilprini (see Gardner, 1937:406). It is generally much smaller than M. helenae (avg. length 69mm. vs. 112mm.), has fewer (3-5) columellar plaits, which are of regularly increasing promi- nence, and has a proportionately smaller body whorl that makes up about three-fifths of the total shell length compared to two-thirds or more of the total shell length in M. helenae.
Chronologically, M. prodroma was the first to appear, followed by M. carolinensis and then by M. helenae. Morphologically, as well as chronologically, M. carolinensis apparently is closer to M. helenae.
No other western Atlantic mitrid has been reported to reach the size of M. helenae. Another Floridian member of the family, M. (Dibaphimitra) florida Gould, 1856, reaches a relatively large size (38-50mm) but has a more convex whorl profile, a shorter spire, a more ventricose body whorl and a white shell with spiral rows of brown dots and some nebulous brown blotches.
Species to which M. helenae could be compared in its color pattern and sculpture in- clude M. versicolor Reeve, 1844, M. nebulosa Reeve, 1844, M. lamarcki Reeve, 1844 and M. serpentina Lamarck, 1822. None of these reach the size of M. helenae, none have its almost volute-like form and all are apparently hmited to the Indo-west Pacific.
Description.— J\iQ shell is large for the genus (98- 123mm in length). It is moderately heavy, fusiform, and has a moderately high spire (about 2/5 of total shell length). The shell surface is smooth and polished. The spire whorls are demarcated by an impressed suture. The spire consists of 2y4 smooth, polished, tightly wound nuclear whorls and 7 or 8 weakly convex postnuclear whorls.
The body whorl is large (about 3/5 of total shell length) and fusoid; it is weakly shoul- dered a short distance anterior to the suture and tapers gradually toward the anterior end. The aperture is long, moderately narrow, and almost rectangular, except at its posterior end. The outer apertural lip is thin and even in a mature specimen. Just below the shoulder margin, on the inner surface of the outer apertural lip, there is a slight swelling extending anteriorly for about 25 mm. The inner lip is oblique and is coated with a thin callus of minor extent. The inner lip bears a series of 9 plaits of various strengths. The two posterior-most are strongest and of these the first is stronger and thicker than the second. These are fol- lowed anteriorly by 1 weak and 6 moderately weak plaits that diminish in strength and ex- tent of projection from the aperture proceeding anteriorly. The siphonal fasciole is well- defined, originating as a white raised ridge at the fifth plait from the upper end of the series. The siphonal notch is well-defined and moderately deep.
Axial sculpture is lacking except for fine growth lines, and erratically occurring stronger lines representing major growth stoppages. Spiral sculpture on the spire whorls consists of numerous fine erratically spaced cords; 2 or 3 immediately below the suture are bunched more closely than the others. The stronger primary cords are sharply raised and bear an interrupted brown and white spotted color pattern that is distinct from the back- ground. Weaker secondary cords are ephemeral and, as such, are not visible uniformly over
Figure 1, 4. Mitra ( Pleioptvgma) helenae n. sp., paratype. Cay Sal Bank, 21.5 m, in lobster pots, length- 123 mm, maximum diameter— 41.1 mm. collection of Ivan Thompson. 2, 5, M. (P.) helenae n.sp., holotype. Cay Sal Bank, 21.5 m, in lobster pots, length— 98.4 mm, maximum diameter— 32. 1 mm, SDSNH Mar. Invert, no. 61863. 3, 6, M. (P.) carolinensis (Conrad, 1840), Pliocene, Clewiston, Florida, length- 103 mm, maximum diameter— 34.8 mm, SDSNH Paleo. no. 07248.
98
.^""^.
<£■ .;i ./A'f''^ .vi-a"*!' ^-'^^f^"
ilip^""
a
Figure 7. M/Vra fP.j carolinensis (Conrad, 1840), protoconch, locality data as in Figure 3.
Figure 8. Mitra (P.) helenae n.sp., protoconch, lo- cality data as in Figure 2.
the shell. This spiral sculpture becomes partially obsolete on the periphery of the body whorl.
The shell is white with numerous irregular diffuse flammules of reddish chestnut brown. The interior of the aperture is porcellaneous white.
Mea5wreweA7/5.—Holotype— length, 98.4mm; greatest diameter, 32.1mm; paratype— length, 123mm (lacking protoconch); greatest diameter, 41.1 mm.
Remarks.— J\\Q holotype and the single paratype were inhabited by hermit crabs at the time they were collected. The holotype is in fresh condition and apparently is not full- grown; it has a thin, immature, outer apertural hp. The paratype has apparently attained full size but it lacks a protoconch; its surface is more worn and the color pattern is com- paratively faded.
Mitra helenae is here considered a living representative of Pleioptygma, a genus that is known otherwise only from Miocene and Pliocene species. Other species previously as- signed to this group include M. carolinensis, M. heilprini and M. prodroma.
Etymologv.— This patronym honors the late Mrs. Helen Thompson of El Cajon, Cah- fornia.
ACKNOWLEDGMENTS
We thank Captain Jack Casey and Mr. Ivan Thompson for their interest and courtesy in providing us with the only known specimens of M. helenae. Mr. David K. Muiliner photographed the specimens and Mr. Clifton Martin supplied references. Mr. Anthony D'Attilio illustrated the protoconchs.
LITERATURE CITED
Bellardi, Luigi
1850. Monografia delle Mitre fossili del Piemonte. Mem. Real. Accad. Sci. Torino, ser. 2, 11:1-34, pis. 1-2. (not seen)
Cernohorsky, W. O.
1970. Systematics of families Mitridae and Volutomitridae (Mollusca, Gastropoda). Bull. Auckland Inst. Mus., 194p.
Conrad, T. A.
1840. New fossil shells from North Carolina. Amer. J. Sci. Arts 39: 387-388.
Cossmann, A. E. M.
1899. Essais de Paleoconchologie Comparee, Paris, 3: 1-201, pis. 1-8.
Gardner, J.
1937. The molluscan fauna of the Alum Bluff" Group of Florida, pt. VI, Pteropoda, Opisthobranchia and Ctenobranchia (in part). U.S. Geol. Surv. Prof Paper 142F, 187p.
Gould, A. A.
1856. Descriptions of new shells. Proc. Boston Soc. Nat. Hist. 6: 11-16.
99
Lamarck, J. B. P. A.
1798. Tableau encyclopedique et methodique des trois regnes de la nature. Paris, pis. 287-390. (not seen)
Philippi, R. A.
1847. Beschreibung zweier neuer conchyliengeschlechter, Dihaphus und Amphichaena nebst einigen be- merkungen uber Cyamium, Ervilia und Entodesma. Arch. Naturg. 13( 1): 61-66, pi. 3. (not seen)
Pilsbry, H. A. and A. A. Olsson
1954. Systems of the Volutidae. Bull. Amer. Paleont. 35(152): 1-36, pis. 1-4 (25-28).
Department of Marine Invertebrates, Natural History Museum, P.O. Box 1390, San Diego, California 92112 and San Diego Shell Club, P.O. Box 1390, San Diego, California 92112.
■^**-^L.»
. ■■■^■i. J*.,
:n. :, ^ '
5-4 a/
DIAGNOSES OF NEW CYPRINID FISHES ^UfivS^**^'
OF ISOLATED WATERS IN THE GREAT BASIN OF WESTERN NORTH AMERICA
CARL L. HUBBS AND ROBERT RUSH MILLER
TRANSACTIONS
OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
VOL. 17, NO. 8 29 SEPTEMBER 1972
DIAGNOSES OF NEW CYPRINID FISHES
OF ISOLATED WATERS IN THE GREAT BASIN
OF WESTERN NORTH AMERICA
CARL L. HUBBS AND ROBERT RUSH MILLER
ABSTRACT.— One new genus, two new species, and six new subspecies are diagnosed from highly restricted endorheicbasinsof the western United States— Relictussolitarius n. gen. andn. sp., from the basins of pluvial lakes Gale, Franklin, Steptoe, and Waring; Gila alvordensis n. sp., from the basin of Lake Alvord; and the following new subspecies: Gila bicolor newarkensls and G. b. euchila ( Lake Newark), and G. b. isolata ( Lake Clover), Rhlnichthys osculus reliquus ( Lake Gilbert), R. o. ollgoporus and R. o. lethoponis ( Lake Clover).
In amplification of our general summary (Hubbs and Miller, 1948), we are now docu- menting in detail the correlations between the hydrographic history of the endorheic waters of the Great Basin and the differentiation of the remnant fish fauna that somehow has man- aged to survive in the pitiful remnants of the pluvial lakes and streams that in late Pleisto- cene time covered about one-fifth of the now arid area. One of the species described herein, and the post-Pleistocene desiccation of the Alvord basin to which it is rigidly confined, are under intensive study; all of the other taxa are integral parts of a major treatise now in final processing (Hubbs and Miller, in press).
The type specimens are deposited in the University of Michigan Museum of Zoology (UMMZ).
Relictus n. gen.
Tvpe species.— Relictus solitarius.
A cyprinid of moderate size (larger than Rhinichthvs), with some distinctive os- teological characters: dorsal crest of maxilla greatly expanded upward and backward: cleithrum slender; supraethmoid elongate, slender medially but notably expanded laterally at front (resembling that of Rhinichthvs ); urohyal long and narrow. Vertebrae 35-39. Phary- ngeal arch moderately strong and heavy, but rather thin and somewhat lacy on the strongly expanded median section; not strongly elevated at the posterior end of the tooth row; with- out a flattened shelf on which a second tooth row might develop; teeth 4—4 (rarely 5—4 or 4— 3). Gill-rakers small and few (7-12, usually 8-11, on first arch). Mouth oblique and termi- nal, completely lacking horny cutting edges; no frenum or barbel. Lateral line obsolescent, rarely extending to below origin of dorsal fin, commonly disrupted; total pores 3-29. Supra- temporal canal seldom complete (only 4 of 76 specimens have the commissure closed), with usually 3 or 4 (0-5) pores in each lateral segment; preoperculomandibular pores 11-19; mandibular pores 3-8. Scales rather small (50-70 transverse rows), poorly imbricated and markedly irregular; each usually vertically oval but sometimes becoming rectangular with age; with numerous radii on all fields (much as in Rhinichthvs and some other Western gen- era). Fins small and strongly rounded; the pelvic especially and uniquely paddlelike; dorsal and pelvic both displaced backward, and both beginning at approximately the same verti- cal (as in the subgenus Siphateles of the genus Gila and in many species of the typical sub- genus Gila); dorsal and pelvic rays typically 8, anal 7. Nuptial tubercles form a highly dis- tinctive pattern on head; the largest uniserially line the infraorbital sensory canal and suborbital margin; large uniserial caducous cones (much stronger than in Gila) line the up- per edge of the first pectoral ray; smaller cones, also strictly uniserial (not forking once as they do in Rhinichthvs) occur along one to several following rays; in high males some tu- bercles develop along outer pelvic rays and along first anal rays. Head and body turgid. Coloration much as in Siphateles. rather even, and often with large melanophores on lower side; lacking the two lateral bands, the head stripe, the paired light spots at caudal base, and
SAN DIEGO SOC. NAT. HIST. TRANS. 17(8); 101-106, 29 SEPTEMBER 1972
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Other features characteristic of Rhinicluhvs. Intestine forming a single, simple, compressed- S loop, as in Rhinichthvs and many other American cyprinids. Karyotype distinguished by a relatively large number (2 large and 8 small) of acrocentric chromosomes but many (12) metacentrics; remaining 28 are subtelocentric and submetocentric (total 50 as in other American cyprinids examined).
Relictus solitarius n. sp.
Holotvpe.—VMMZ 186904, a nuptial male 60.3 mm in standard length, from upper, hillside spring on Kirkpatrick Ranch (earlier called "Atwood Ranch," later called "Don Phalan Ranch") on east side of Butte Valley north of the narrows, in east part of T.29 N., R.62 E., Elko County, Nevada, 21 km northwest of Currie; collected by the Hubbs family June 27, 1942 (collection H42-47).
The characters of the species are essentially those of the genus. Counts for the holotype and the paratypes (UMMZ 141518) from the same collection follow. Rays: dorsal 7-8 (mean 7.40), anal 6-7 (6.95), caudal 18-21 (19.17), pectoral 13-16 (14.17), pelvic 7-9 (7.95). Vertebrae: 35-37 (36.05). Scale-row counts: lateral-line 50-57 (54.6), predorsal 30-33 (31.4), dorsal to anal origins 2 1 -23 (22.4), around body 55-58(55.8), around peduncle 30-3 1 (30.2). Pores: lateral-line 13-26 (18.4), supratemporal 2-4 (3.0), mandibular 4-7 (5.33). Gill-rakers 7-1 1 (8.90). Measurements of holotype in thousandths of standard length: predorsal length 579, anal origin to caudal base 318, body depth 295, caudal-peduncle depth 158, head length 282, head depth 207, head width 170, snout length 76, orbit length 59, upper-jaw length 82, mandible length 1 02, interorbital width 88, suborbital width 4 1 , depressed-dorsal length 223, caudal length 238, pectoral length 208, pelvic length 160.
Gila alvordensis n. sp.
Holotvpe.— UMMZ 130495, an adult female 70.7 mm in standard length, from Trout Creek, tributary to Alvord Desert, in Harney County, Oregon; just below the canyon and just below bridge where roads to Denio, Jordan Valley, and Fields meet, in southeast part of T.39 S., R.36 E.; collected by the Hubbs family July 26, 1934 (collection M34-87).
A chub of moderate size (though usually greatly dwarfed in Borax Lake), agreeing most closely with Siphateles (now regarded as a subgenus of Gila), but with scales much reduced in size and more embedded, and with radii all around, much as in Rhinichthvs and Relictus. Pharyngeal teeth uniserial, normally 5—4 (rarely 5—5, 4—5, 4—4, or 4—3), with the first tooth on a moderately elevated base. Nuptial tubercles strong on the flattened and moderately twisted pectoral fin of nuptial males; developed on the outer half (by number) of the rays, over at least two-thirds of the width of the fin, covering nearly the full length of each thickened ray; uniserial and small on the only moderately thickened outermost ray; the row branching once on each of the following rays: very strong on rays 2 and 3 (on the ridge of the distorted fin), then decreasing inward in number and size; each tubercle set on a single ray segment and rising from a large rounded base to end in a rather narrow and sharply pointed, essentially erect, tip (with only a slight cant basad); in high males similar but weaker tubercles discernible on the pelvic fin, but not on other fins; minute excres- cences, simulating tubercles, over the top and sides of head in high males. General color dusky with a continuous file of large melanophores, usually uniserial or nearly so, ahgned on either side of the back.
Fin rays: dorsal 7-10 (normally 7), anal 6-9 (normally 7), caudal 17-20 (normally 19), pectoral 12-17, pelvic 7-9 (normally 8). Gill-rakers: 16-22, usually short, especially forward. Measurements of holotype in thousandths of standard length: predorsal length 568, anal origin to caudal base 312, body depth 250, caudal-peduncle depth 129, head length 267, head depth 163, head width 139, snout length 77, orbit length 48. upper-jaw length 72, man- dible length 100, interorbital width 85, suborbital width 33, depressed-dorsal length 204, caudal length 238, pectoral length 191, pelvic length 141, pelvic insertion to anal origin 185.
Gila bicolor newarkensis n. subsp. Holotype. -UMMZ 188893, a nuptial male 68.0 mm in standard length, from spring in
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Newark Valley on west side near Diamond Peak (called South Peak in 1934), on alluvial slope about opposite south end of Newark Dry Lake, near middle of T.IO N., R.55 E., in northwestern White Pine County, Nevada; collected by the Hubbs family September 11, 1934 (collection M34-206).
A medium to rather small-sized chub (largest of many specimens 97 mm long). Gen- eral color tone darker and more uniform than in G. b. ohesa, not closely approaching the bicolored pattern of that subspecies; dark pigmentation of sides less uniform than in other forms, because of the thick and broad concentration of melanophores around margins of scale pockets, leaving the rounded central area of pockets largely clear, to form rather con- spicuous stripes along the horizontal scale rows; the dark pigment extending farther down, usually more or less completely rounding caudal peduncle; basicaudal spot replaced by a thin blackish streak along curving posterior border of squamation. Head and body strongly turgid, rounded in all aspects. Muzzle broadly rounded; mouth generally low, curved, and less oblique than usual, becoming more nearly horizontal forward; mandible slightly in- cluded at tip. Nuchal region more humped than in most forms; dorsal contour scarcely ele- vated at front of dorsal tin. Fins distinctively rounded, without any falcation; unusually large; sexual dimorphism in fin lengths extreme. Anal-ray count averaging low, modally 7; pelvic rays averaging 8.10 and 8.66 in two races. Vertebral and scale counts averaging low (scale counts around body averaging fewer than 47: those around peduncle fewer than 27). Gill-rakers outstandingly few (modally 12), short, soft, and swollen. Pharyngeal teeth usu- ally 5-4.
Gila bicolor euchila n. subsp.
Holotype.—VMMZ 124938, an adult female 141 mm in standard length, from Fish Creek Springs in northwestern part of Fish Creek (Little Smoky) Valley, in main ditch about 0.5 km below junction of two main spring-fed branches, in Sec. 8, T. 16 N.. R.53 E.; near southwest corner of Eureka County, Nevada; collected by the Hubbs family August 17, 1938 (collection M38-134).
An outstandingly large chub (for an isolated population), males reaching 114 mm and females 149 mm; the distinction in bulk is even more striking than in length. Agreeing with G. b. newarkensis in color pattern (as described above), but differing in color: females deep moss-green on back, with scale borders tending to converge backward, with sides usually mottled or speckled on individual scales, with lower fins deep-olive, grading to blackish on rays and to yellowish on membranes, and with dorsal and caudal fins very dark olive; adult males with much more gilt than females on cheeks, opercles, and sides, and with gilt on body somewhat rosy, with blue reflections rather strong on lower sides, with scale margins ventrally orange-red, with a considerable wash of lemon-orange on dorsal and caudal fins, with axils of paired fins rather bright orange, with this color rather strong on interradial membranes, and with rays of lower fins deep-olive. Body contours typically much less tur- gid than in G. b. newarkensis, and head much more pointed in side view, with the tip much nearer horizontal midline of head; anterodorsal profile much straighter and less decurved; head much larger: suborbital and muzzle wide and flat: mouth much larger, straighter, and more oblique, with particularly massive lips and mandible (yet tip of mandible is also slightly included). Fins hardly falcate, but less rounded than in G. b. newarkemis. Supra- temporal canal, as also only in G. b. newarkensis, but in contrast with other forms of G. bico- lor, more often complete than incomplete. Dorsal fin more posteriorly inserted than in other subspecies, even more than in G. b. newarkensis. Paired fins in males larger than in nearly all other populations studied. Scale-row counts, as in G. b. newarkensis, average lower than in other forms, with little overlap in most categories. Gill-rakers average few and generally shorter and less hard than usual in G. b. obesa.
Gila bicolor isolata n. subsp.
Holotype.-VMMZ 186906, an adult female 85.8 mm in standard length, from Warm Springs of Independence Valley (also known as Ralph's Warm Springs), just off base of Pe- quop Mountains, approximately on edge of bed of pluvial Lake Clover, on either side of
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T. 35-36 line near middle of R.66 E., in east-central Elko County, Nevada; collected by Miller and Hubbs August 25, 1965 (collection M65-33).
A somewhat dwarfed chub (largest male 73 mm and largest female 91 mm long). Un- pigmented ventral band wider than in G. b. newarkensis and G. b. eiichila\ the pigment almost never rounding peduncle below; however, almost all specimens have a highly dis- tinctive black speck on midventral line at the very outset of the lower procurrent caudal rays. Anterodorsal profile less rounded and decurved than usual in G. b. newarkensis. As in G. b. obesa, contrasting with G. b. newarkensis and G. b. euchila front tips of mandible and upper lip about even; in contrast with G. b. newarkensis, mouth nearly straight, and suffi- ciently oblique to rise nearly to lateral midline of head. Lateral line, even in larger adults, usually incomplete posteriorly, lacking at least on peduncle, usually throughout that region and in some farther forward, where it may be either lacking or interrupted. Supratemporal canal regularly complete, as in none of the other subspecies studied. Dorsal fin, with little overlap, farther back than in any of the other forms considered except G. b. newarkensis and G. b. euchila. Distance from anal origin to caudal base averaging shorter than in the other subspecies considered, including G. b. newarkensis but not G. b. euchila. Mandible aver- aging larger than in other forms considered, except G. b. euchila and the variant form of G. b. obesa in Sulphur Spring (Diamond Valley). Sexual dimorphism of pectoral fin about as in G. b. obesa, much less than in G. b. newarkensis and G. b. euchila. Anal rays predominantly 7 rather than 8— as also in G. b. euchila and two of the three populations of G. b. newarkensis studied. Pelvic rays predominantly 8 instead of 9 (as in two G. b. newarkensis populations). Numbers of vertebrae and scale rows low. Gill-rakers also few (8-14, averaging 11.14). Rakers essentially like those of G. b. obesa.
Rhinichthys osculus reliquus n. subsp.
Holotvpe.—VMMZ 124906, an adult female 67 mm in standard length, from spring- fed creek in a grassy meadow in the partly enclosed southwestern arm of Grass Valley, 13 km east of Mt. Callaghan, in course of Callaghan (Woodward) Creek, on Grass Valley Ranch, in SW 1/4, Sec. 10, T.21 N., R.46 E., in eastern Lander County, Nevada; collected by Hubbs family and Miller, August 9, 1938 (collection M38-116).
A relatively large dace, despite its occurrence (now apparently extinct) in a restricted habitat; largest size 82 mm. Quite different in appearance from R. o. robustus: body less speckled; blackened regenerated scales rather fewer and less emphasized; underlying main dark lateral band generally broader, more solid, more even-edged. Pattern further in- tensified by more definitely lightened ground color between this lateral band and the dark, broad predorsal stripe. Deep-lying giant melanophores often formed on the lower sides, especially posteriorly, much more conspicuous than in R. o. robustus, forming punc- ticulations somewhat similar to those on this region in subgenus Siphateles of Gila. Lower dark lateral line, usually rather well developed in R. o. robustus, obsolescent. A very dis- tinctive dark streak or wedge developed along lower border of caudal peduncle. Head char- acteristically darkened from the dark area of the suborbital region, and from front of mouth, upward and backward over front and top of head: horizontal dark stripe on snout, characteristic of R. o. robustus, barely even suggested. Vertical fins also more uniformly darkened, and less speckled, than in R. o. robustus, with hardly a trace of the especial black- ening at the bifurcation of the rays. Lower lip, even in specimens with lower surface of head elsewhere devoid of pigment, heavily punctate all around. Red color often apparent in Rhi- nichthys osculus, in axils of paired fins, about mouth, and on preopercle, scarcely evident in life. Body more turgid in nuchal region, and snout more rounded, more declivous, and broader (overall width of mouth, in consequence, approximately equally as long as, rather than shorter than, the snout). Mouth as seen from below broadly U-shaped, instead of being narrower approaching a V. Barbel almost invariably absent. Lateral line on both body and head greatly reduced; supratemporal canal commissure consistently interrupted medially, typically very widely. Body averaging slenderer than in other forms; caudal-pe- duncle depth is less than in R. o. lethoporus, with slight overlap. Pelvic-fin insertion more posterior than in any other form considered. Sexual dimorphism in pectoral-fin length most extreme. Dorsal fin more posteriorly inserted in males than in females, on the average, con-
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trary to findings for other forms oi' Rhinichthvs (and for cyprinids in general). Pectoral-ray counts on the average lower than in other subspecies treated. Caudal vertebrae definitely averaging fewer. Scale counts averaging consistently higher than in the two forms described below.
Rhinichthys osculus oligoporus n. subsp.
Holotvpe.—VMMZ 186902, an adult female 55.2 mm in standard length, from Warm Springs in Clover Valley, at Warm Creek (formerly Clover) Ranch, near southeastern cor- ner of Clover Valley, near foot of bajada just above the ancient bed of Lake Clover, in Sec. 7, T.33 N., R.61 E., in southeastern Elko County, Nevada; collected by James E. Deacon and Mary Beth Rheuben September 14, 1964.
A dace of about average size. Body more extensively speckled with black than in R. o. robustus; lower lateral band as a rule much less or not at all evident; dark pigmentation around snout generally diffused, with no evidence of the usual horizontal black streak in front of eye. but retaining a tendency for its continuation across opercle. Jet-black basicau- dal wedge much reduced in size and intensity, more disrupted, occasionally hardly evident. Dusky dashes on dorsal and caudal fins tending to be more numerous, but barely evident on anal fin (where often evident in R. o. robustus); these marks much less apt to form in, and to be largely restricted to, the crotches of the bifurcating rays. Main lateral band bordered above by a light streak, barely evident in R. o. robustus. Life color on back bright-olive or golden-green and below silvery, with an intervening bright-gilt stripe and with dusky mot- tling. Axils of paired fins and base of anal in adult male clear red (contrasting with males of R. o. reliquus). Differing from R. o. robustus in general form: outlines of body, and espe- cially of head, more curved; head in particular more rounded, in both dorsal and lateral aspects. Mouth tending to be more definitely lower than lower border of eye, and generally more curved; whole aspect bulkier. Barbel invariably absent (51 specimens). Reduction of lateral line on body extreme (as in R. o. reliquus and R. o. lethoporus). Suborbital averaging slightly narrower than in other forms studied, R. o. lethoporus excepted. Pelvic-fin insertion averaging farther back than in typical R. o. robustus or in R. o. lethoporus, but farther for- ward than in R. o. reliquus. Number of rays in paired fins somewhat reduced in average number. Scale counts averaging definitely lower than in R. o. reliquus, about the same or not quite so low as in R. o. lethoporus, and somewhat lower than in more typical races of R. o. robustus.
Rhinichthys osculus lethoporus n. subsp.
Holotvpe.—VMMZ 186905, an adult female 35.3 mm in standard length, from Warm Springs in Independence Valley (the same collection from which the type of Gila bicolor isolata was taken; see above).
Apparently the most dwarfed dace of any in the general area under consideration: the largest male measures 34 mm and the largest female 39 mm in standard length, among the 101 specimens collected (not much larger than young-of-the-year of some of the other forms). Dark speckling usually very fine, and tending to extend downward across the caudal peduncle; lower edge of peduncle often with a blackish wedge or streak. Horizontal stripe on head restricted largely to snout and upper part of opercle, usually developed, at least as a trace (much as in R. o. robustus, contrasting with R. o. oligoporus). Blackening of crotches at bifurcation of dorsal and caudal rays, and occasionally of anal rays, more as in R. o. robustus than in R. o. oligoporus. Light streak above main lateral band, frequent in R. o. oligoporus, obvious in only a few of the preserved specimens. Form particularly distinctive, unusually compressed for a Rhinichthys: greatest body width steps over the curve of the sides about 2.0 times, rather than about 1 .5 times in R. o. robustus {R. o. oligoporus approximately inter- mediate). Anterior profile less flattened than in R. o. robustus and less arched than in R. o. oligoporus. Anterior part of head more foreshortened than in R. o. robustus, but rather more pointed (less rounded) than in R. o. oligoporus. Mouth definitely straighter than in R. o. oligoporus, but more oblique, rising forward to a horizontal through the lower edge of the eye. Barbel almost invariably absent, as in the two other subspecies here named. As in the other two, development of lateral line greatly reduced— even more than in R. o. oligoporus.
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less extreme than in R. o. reliquus. The body proper, and more strikingly the caudal pe- duncle, averaging deeper than in the two other forms here described. Dorsal and anal fins are inserted farther back than in R. o. robustus. The mouth, strikingly, is strongly oblique and nearly straight, the upper jaw rising to about level with middle of eye. Pectoral rays average few (12.72). Vertebrae and scale rows somewhat reduced in number.
LITERATURE CITED
Hubbs, C. L.. and R. R. Miller
1948. 11. The zoological evidence/Correlation between fish distribution and hydrographic history in the desert basins of western United States. In, The Great Basin, with emphasis on Glacial and Postglacial times. Bull. Univ. Utah, 39(20). Biol. Ser. 10(7): 17-166, figs. 10-29, map 1.
In press. Hydrographic history and relict fishes of the north-central Great Basin. Mem., California Acad. Sci.
Scripps Institution of Oceanography, La Jolla, California 92037 and The University of Michigan, Museum of Zoology, Ann Arbor, Michigan 48104.
-Wfi-S
MUS. CCMP. ^OOU UBRARV
JUN22t973
HARVARD UNlVERSITYi
PATTERNS OF LARVAL DEVELOPMENT IN STENOGLOSSAN GASTROPODS
GEORGE E. RADWIN AND J. LOCKWOOD CHAMBERLIN
TRANSACTIONS
OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
VOL. 17, NO. 9 12 MARCH 1973
PATTERNS OF LARVAL DEVELOPMENT IN STENOGLOSSAN GASTROPODS
GEORGE E. RADWIN AND J. LOCKWOOD CHAMBERLIN
ABSTRACT.— Studies of egg capsules and the mode of development in certain species of stenoglossan pro- sobranchs tVom the northeastern Gulf of Mexico revealed an apparent disproportionate number of species with non-pelagic larval development. Thorson ( 1950) suggested that among shallow-water marine in- vertebrates incidence of pelagic development increased from the arctic to the tropics and predominated in the subtropics and tropics. His conclusions were based largely on prosobranch moUusks. We suggest that the mode of early development in the Stenoglossa tends to follow phyletic lines, regardless of latitude or climatic conditions.
Many prosobranch gastropods lay their eggs in parchment-Hke capsules, separately or in clusters, attached to firm substrata. Unequivocal species identification is possible when the capsules are deposited in an aquarium containing individuals of a single species or when observations on ovipositing snails are made. The young of most higher pro- sobranchs pass the veliger stage within the capsule and may be sufficiently developed be- fore emergence to be identifiable either by the sculpture of the early teloconch sculpture or by the radular dentition. In other groups the young are released as veligers and are car- ried in the plankton until they settle and metamorphose. Pearse (1969) described a third mode of development which seems to be intermediate between these two. In this type a modified veliger (called by some authors a veUconcha) emerges from the egg capsule and swims feebly for a short time in the bottom-most layer of water before settling. He has called this a demersal mode of development. The only stenoglossan species we know to exhibit this kind of development is Olivella verreauxi (Duclos).
Identification of capsules of marine gastropod species can contribute to distributional data which may be useful in zoogeographic studies and may serve as an ecological tool in determining the reproductive range of a species. In addition, their use as taxonomic char- acters at the generic level should be considered.
In this paper the spawning conditions and egg capsules of nine species of stenoglos- san mollusks from the northeastern Gulf of Mexico are described. These observations were made from March 1963 to July 1964. The species treated are: Phyllonotus pomum (Gmelin), Muricanthus fulvescens (Sowerby), Calotrophon ostrearum (Conrad), JJrosal- pinx tampaensis (Conrad), Urosalpinx perrugata (Conrad), Thais floridana (Conrad), Can- tharus cancellarius (Conrad), Cantharus multangulus (Philippi), and Pollia tincta (Con- rad).
SPAWNING SITES, EGG CAPSULES, AND LARVAL DEVELOPMENT
Phyllonotus pomum (Gmelin, 1791) (Fig. 1, la). Localities: St. Teresa and Bay Mouth Bar, Franklin Co., Fla., attached to large, empty bivalve shells. Period: May-July. The capsules are deposited in irregular compact masses up to 30 cm across; individual cap- sules are superficially similar to those of Buccinum and Neptunea. From two to five larvae develop in each.
Tryon (1880), Webb (1942), and Perry and Schwengel (1955) described and figured the capsule mass of P. pomum, and Webb reported communal spawning by as many as twenty-five females. This egg mass is similar to that reported for Murex senegalensis (see Knudsen, 1950). D'Asaro (1970b) reported non-pelagic development for P. pomum.
Muricanthus fulvescens (Sowerby, 1834) (Fig. 5). Locality: St. Andrews State Park, Bay Co., Fla., attached to rocks of the breakwater. Period: June-August. Capsules depos- ited in clusters with their bases fused. Each capsule is a flattened cylinder about 25 mm
SAN DIEGOSOC. NAT. HIST.. TRANS. 17(9): 107-118. 12 MARCH 1973
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high, with the top broader than the base. All were empty when collected. Identification was made on the basis of a laying female and an egg mass (catalogue no. 599643) in the collection of the Division of Mollusks, U.S. National Museum of Natural History. Moore (1961: 26) figured a similar capsule collected off Mississippi as M. fiilvescens. He gave the height of "one typical specimen" as 14 mm which, from the examples we have seen, seems to be too small. He also reported that there are over one hundred eggs in each cap- sule.
Calotrophon ostrearum (Conrad, 1846) (Fig. 7,7a). Localities: 1) St. Teresa. Franklin Co., Fla., on the blades of turtle grass; 2) dredged in 13 m off" Dog Island, Franklin Co., Fla., attached to the sides of egg capsules of Ficus communis (Roding); and 3) attached to the walls of aquaria in which specimens of C ostrearum were isolated (see Radwin and Wells, 1968). Period: early May to mid-June. Numerous capsules are laid individually, their bases separated; they are roughly semicircular, average about 4 mm high, and when first deposited usually contain 3 to 5 large, spherical, reddish eggs. Emergence is in the crawling stage (pelagic stage absent). Egg capsules apparently of this species were attrib- uted by Perry and Schwengel (1955) to both Urosalpinx perrugata and Cantharus florid- anus.
Urosalpinx perrugata (Conrad, 1846) (Fig. 2). Localities: 1) Bay Mouth Bar. Alligator Harbor, Franklin Co., Fla., attached to empty mollusk shells; 2) attached to the sides and bottoms of aquaria in which adults were isolated (see Radwin and Wells, 1968). Period: late April to mid-June. Numerous erect capsules, with fused bases, are deposited in a mat; the capsules, about 10 mm high, are inversely pyramidal and have two lateral alae and apical protuberances. An egg mass may contain as many as 200 capsules. A large but un- determined number of eggs is initially deposited; the majority are apparently nurse-eggs, since only 5 to 15 larvae develop fully. Larvae emerge in the crawling stage (pelagic stage absent). Egg capsules of this species are misidentified in Perry and Schwengel (1955) as the product of Nassarius vibex.
Urosalpinx tampaensis (Conrad, 1846) (Fig. 3). Locality: Attached to the floor of an aquarium in which individuals of this species were isolated (see Radwin and Wells, 1968). Period: March (in aquarium). The erect egg capsules, about 8 mm high, are deposited singly. They resemble plump fingers on stalks and are more similar to those of Eupleura sulcidentata (see Perry and Schwengel, 1955) than to those of the other two western Atlan- tic species of Urosalpinx (cinerea and perrugata). Each capsule contains numerous eggs which, in our material, did not develop.
Thais floridana (Conrad, 1837) (Fig. 4,4a). (For characters distinguishing this species from T. haemastoma, see Radwin and Wells, 1968.) Locality: St. Andrews State Park, Bay Co., Fla., attached to empty bivalve shells and rocks of the breakwater. Period: July- August. The elongate, trough-shaped capsules are about 12 mm high, have apical escape pores, and are deposited in large masses. The capsules at the base of a mass tend to be nearly erect and are attached side by side to the substratum, with their bases fused. Other capsules are attached to those beneath in an arborescent pattern.
Burkenroad (1931) figured a capsule mass and commented on the hatching process. D'Asaro (1966), who figured the capsule and described the spawning and embryology in detail, reported communal spawning occurring from February through November at Miami, Fla. He suggested that spawning "probably occurs also in December and January when the temperature is above average." A shorter spawning season in the northeastern Gulf of Mexico is consistent with the shorter period of warm water temperature there. Large numbers of veligers emerge and have a prolonged pelagic development (D'Asaro, 1966). This mode of development (also reported by other workers for this species in North American waters) contrasts with that of most stenoglossans treated in this paper.
Thorson ( 1946, 1950) cited T. floridana as having pelagic development in some partSi of its range and direct, non-pelagic development in others. This may be correct, but hisj evidence is apparently inferred from Lamy (1928), who referred, in turn, to Korschelt and! Heider (1900), which reference we have not seen. Lamy reported only that many of the! larvae die after cleavage and are then eaten by the others in the capsule. Although this! "nurse-egg" type of feeding is usually associated with non-pelagic larval development, itj
109
Figure 1. PhvUonmus pomiim—^even capsules from an egg mass. la. P. pomtimsmaW egg mass. 2. Urosalpinx perrugaiiisingk egg capsule. 3, Urosalpinx iampaensis—^\n^\c egg capsule. 4, Thais fhridana—single egg cap- sule. 4a, Thais fJoridana-ponion of an egg mass. 5, Muricanihi/s fulvescens-single egg capsule. 6. Cantharus nnilranguhis— single egg capsule. 6a. Cantharus multanguhis~\.op view of a single egg capsule. 7. Caloirophon os- /rertn///;— single egg capsule. 7a. Caloirophon osirearum—side view of a single egg capsule. 8, Cantharus cancel- /ani/.s-single egg capsule. 8a. Cantharus cancellarins-lop view of a single egg ca'psule.
110
is not proof of such development, as Thorson ( 1950) pointed out for Natica catena.
Caniharus cancellarius (Conrad, 1846) (Fig. 8, 8a). Localities: 1) Bay Mouth Bar, Al- ligator Harbor, Franklin Co., Fla., on empty mollusk shells; 2) Seahorse Key, Cedar Keys, Levy Co., Fla., on stones and empty mollusk shells; and 3) attached to the sides of aquaria in which adults were isolated (Radwin and Wells, 1968). Period: early May to late June. The erect capsules are deposited in a mat with their bases confluent. In nature the mats contained 15-20 capsules; the number of capsules laid in aquaria was smaller. Indi- vidual capsules are roughly rectangular, have four distinctive spinose projections at the top, and are about 4 mm high. In each capsule approximately 10-20 larvae develop to the crawling stage.
Moore (1961:26) figured a capsule of this species as Cantharus reticidatus. He also noted that on the Mississippi coast "these capsules are rather common objects during March, April, and May," and that from one capsule "a dozen or more eggs hatch out while still in the veliger stage." We have seen no other report of pelagic development in this species or elsewhere in the entire family Buccinidae.
Cantharus tmdtanguhis (Philippi, 1849) (Fig. 6. 6a). Capsules illustrated in Perry and Schwengel (1955), fig. 340. Localities: 1) Bay Mouth Bar, Alligator Harbor, Franklin Co., Fla.; 2) St. Teresa, Franklin Co., Fla.; and 3) deposited on the floor of aquaria. The cap- sules collected in the field were on shells and turtle grass. Period: May-July. Each capsule is inversely pyramidal and about 4 mm high; the top surface bears four spine-like projec- tions. The capsule mass is a mat formed by the confluent bases of the capsules. When first deposited each capsule contains 8-20 flesh-colored eggs, a number of which apparently serve as nurse-eggs, as only a few crawling-stage larvae eventually emerge from each cap- sule.
Pollia tincta (Conrad, 1846) (see Perry and Schwengel, 1955; Lebour, 1945). Local- ities: St. Teresa, Franklin Co., Fla., and Seahorse Key, Cedar Keys, Levy Co., Fla., on shells and small rocks. Period: June-July. Clusters of several capsules are deposited, each about 5 mm high, broadly goblet-shaped and basally pedunculate. Each capsule contains 5 to 15 eggs, which, in our material, did not hatch. Lebour (1945) described the larval de- velopment as non-pelagic. Generic distinction o^ Cantharus and Pollia (as Pisania), based on radular dentition (see Troschel, 1866), is corroborated by differences in egg capsule morphology. Cantharus capsules are four-sided and rectangular or inversely pyramidal, with a flat top. Pollia capsules are goblet-shaped.
DISCUSSION
The nine species studied belong in either the family Muricidae (six species) or the Buccinidae (three species), and constitute a majority of these families reported to live in the area of field work (Perry and Schwengel, 1955). The two families are both in the sub- order Stenoglossa, order Neogastropoda.
Among shallow-water, benthic, marine invertebrates, Thorson ( 1950) found that spe- cies with pelagic larval stages were rare in polar regions but increased, and indeed pre- dominated toward the tropics. This conclusion was based primarily on samples of pro- sobranch mollusks from several widely separated areas. However, our data and those of D'Asaro (1970) indicate that at least in the stenoglossans, non-pelagic forms of devel- opment may be more common in tropical waters than is generally recognized. Thorson's data demonstrate a substantial increase in the percentage of species with pelagic devel- opment from arctic to temperate waters (0% in East Greenland to 63.5% in southern Eng- land) but they show a much smaller increase in percentage from temperate to tropical wa- ters (e.g. southern England to a) Canary Islands, 4.5%; b) Persian Gulf, 11.5%; c) Bermuda, 21.5%). These facts have led us to question whether the proportional increase implied by Thorson ( 1950) is demonstrable in lower latitudes.
A review of the literature on modes of larval development among marine pro- sobranchs shows that in the Archaeogastropoda there is no clear predominance of either pelagic or non-pelagic development. In the Mesogastropoda, however, pelagic devel- opment predominates. Within the Neogastropoda the suborder Toxoglossa exhibits pela- gic larval development, whereas the suborder Stenoglossa is the only major prosobranch
Ill
group in which non-pelagic larval development seems to clearly predominate (Table 1).
The apparent predominance of non-pelagic development in the Stenoglossa. regard- less of latitude, as well as the abundance of species of this suborder in lower latitudes sug- gests that the Stenoglossa were under-represented in at least some of the areas discussed by Thorson. The Bermudas, the Canaries, and the Persian Gulf are not typical of the main tropical and subtropical shelf regions of the world. The first two are small island groups, separated from the adjacent mainland by deep water (over 1.000 m), and the third is a hypersaline body of water with excessively high water temperatures (Mohr, 1929) and a restricted outlet to the Indian Ocean.
Bermuda— Lehoufs (1945) data, on which Thorson (1950) based his estimate of 85% of Bermudan species having pelagic development, are biased toward species with pelagic development, as her study was based principally on plankton samples. Only 29 of her prosobranch species were sufficiently identified to be used in a calculation. Of these, only three (10%) are stenoglossans; two have non-pelagic development. All 26 of the non-sten- oglossans have pelagic development.
The actual percentage of Bermudan prosobranchs with pelagic development, though apparently less than 85% may, nevertheless, be higher than is typical of tropical and sub- tropical western Atlantic areas. Evidence for this supposition stems from the fact that stenoglossans make up a smaller percentage of total prosobranchs at Bermuda than is typical of other similar areas. Peile (1927) listed 215 Bermudan species of marine pro- sobranchs, excluding abyssal species, of which 21% are stenoglossans. In comparison, fau- nal lists for the adjacent mainland and Caribbean island areas give the following percent- ages of stenoglossans: western Florida, 28% (Perry and Schwengel, 1955); West Indies, 29- 32% (Arango, 1878; Dall and Simpson, 1901; Morch, 1878); Brazil, 32% (Lange de Mor- retes, 1949).
Canary Islands— Thorson (1950) reported that 68% of the Canary Islands marine prosobranchs exhibit pelagic development. Faunal lists for these islands and for the adja- cent coast of western Africa indicate a situation parallel to that in Bermuda, with fewer stenoglossans among marine prosobranchs at the islands than at the mainland areas: Ca- naries, 30% (Dautzenberg, 1890, 1891); western Africa, 37% (Nickles, 1950). Sao Thome, in a more tropical position off' the western coast of Africa, has an essentially similar situa- tion; 28% of the marine prosobranchs are stenoglossan (Tomlin and Shakleford, 1923).
Evidence of a lower percentage of prosobranchs with non-pelagic larval development at Bermuda, the Canaries, and Sao Thome is, in itself, of biogeographical and ecological interest. The faunal Hsts cited above show that the marine moUusks of these islands in- clude few endemics. Such low endemism is evidence of recent faunal origin by immigra- tion. The marine molluscan fauna of Bermuda is considered a depauperate Antillean fauna (Warmke and Abbott, 1961), and the prosobranchs of the Canaries and Sao Thome are just as clearly depauperate western African. The colonization of these islands largely by species with pelagic larvae could be attributed to their ability, as larvae, to traverse the geographical and bathymetric barriers isolating the islands from the mainland.
Persian Gulf.— Thorson (1940a, 1950) found that 75% of the prosobranch species studied from the Persian Gulf had pelagic development. His data seems moderately biased toward such species as only 24% of them (5 of 21 species) were stenoglossans. Mel- vill and Standen (1901) and Melvill (1928) indicate that just over 30% of the marine pro- sobranchs from this area are stenoglossans.
In view of Thorson's original data showing only a small increase in the percentages of prosobranch species with pelagic larval development from temperate to tropical wa- ters the question arises whether any significant increase exists. Regardless of the answer to this question— and our evidence is not enough to resolve it— there remams the question of why a steep gradient exists in higher latitudes but only a weak one (if, indeed, any exists) in lower latitudes. Of course, data on larval ecology and distribution must include other invertebrate groups as well.
After a draft of this paper was sent to Thorson in 1968, he informed us (in litt.) that the data he had compiled on stenoglossan early development, more extensive than the data in Table I, suggest an appreciably lower percentage of species with non-pelagic de-
112
TABLE I OCCURRENCE OF PELAGIC AND NON-PELAGIC LARVAL DEVELOPMENT WITHIN THE STENOGLOSSA
|
Superfamily |
|
|
Family |
No. Species With |
|
Genus |
Pelagic Larvae |
|
Muricacea |
|
|
Rapanidae |
|
|
Rapana |
3 |
|
Muricidae |
|
|
Murex |
4 |
|
Chicoreus |
— |
|
Phvllonotus |
3 |
|
Boreotruphon |
— |
|
Caloirophon |
— |
|
Bedevina |
1 |
|
Bedeva \ Favartia \ |
— |
|
— |
|
|
Viiularia |
1 |
|
Ceratosioma |
— |
|
Ocenehra \ |
— |
|
Vrosalpinx \ |
— |
|
Eupleura |
\ — |
|
Thaididae |
\ |
|
Purpura |
\ 1 |
|
Neptunea |
\ — |
|
Siphonalia |
\ — |
|
Pollia |
\ — |
|
"Cantharus" |
\ — |
|
Buccinum |
\ — |
|
Volutharpa |
V- |
|
Macron |
—V |
|
Chauvetia |
— \ |
|
Melongenidae |
\ |
|
Melongena |
— \ |
|
Syrinx |
— \ |
|
Busycon |
\ |
|
Hemifusus |
— |
|
Fascioiariidae |
|
|
Leucozonia |
— |
|
Peristernia |
— |
|
Fasciolaria |
— |
|
Pleuroploca |
— |
|
Fusinus |
— |
|
Troschelia |
— |
|
Volutacea |
|
|
Volutidae |
|
|
Valuta |
— |
|
Thais |
9 |
|
Nucella |
— |
|
Buccinacea |
|
|
Columbellidae |
|
|
Pyrene |
— |
|
Milrella |
1 |
|
Anachis |
5 |
|
Zafrona |
1 |
|
Astvris |
— |
|
Amphissa |
1 / |
|
Columhella |
2 / |
|
Nassariidae |
/ |
|
Nassarius |
II / |
|
Trilia |
2 / |
|
llyanassa |
1/ |
|
Buccinidae |
/ |
|
Beriiii^ius (Jumahil |
/— |
|
Volutopsius |
/ — |
|
Pyrulofusus |
/ — |
|
Colus |
/ — |
|
Plicifusus |
/ — |
|
A lei 1 hoe |
/ — |
|
Melo |
/ — |
|
Cyniha |
/ — |
|
Cymhiola |
/ — |
|
Marginellidae |
/ |
|
Persicula . |
/ — |
|
Mar^inella / |
— |
|
Prunum / |
— |
|
Cancellariidae / |
|
|
( aneellaria / |
— |
|
Admete / |
— |
|
Vasidae / |
|
|
Vasum / |
— |
|
Mitridae / |
|
|
Siri^atella |
3 |
|
Atriniilra |
1 |
|
Turbincllidae |
|
|
lurhinella (XancusI |
— |
|
Olividae |
|
|
Ancilla |
— |
|
Olivella |
— |
|
Oliva |
1 |
|
X — Jt. Allison Kay, personal |
communication |
|
XX -/this paper |
No. Species With Non-pelagic Larvae
Reference
18,37.83
45,80
6,15.24.26,43.45,49,63,83
30,39,47
3,17.30,41,42,45,63.79.83.92.93
3.5
'^
21,30,50,82
30,85
22,32 .
30.82,84,xx
50 \
33 \
6,20.38,88
51
9,45
43 43 26
43 82
26
26.66 16
26
63
6,30,53,67
65
12
TABLhI OCCURRENCE OF PELAGIC AND NON-PELAGIC LARVAL DEVELOPMENT WITHIN THE STENOGLOSSA
Superlamily lamily (ienus
Muricacea
Rapanidac
Rapana Muricidae
Murex
Chicoreus
Phvllonoius
Boreoirophon
Cahlrophon
Bedevina
Bedeva
Favartia
Vitularia
Ceratostoma
Ocenehra
Urosalpinx
Eupleura Thaididae
Purpura
Thais
Nucella Buccinacea
Columbellidae
Pyrene
Miirella
Anachis
Zafrona
Aslyris
Amphissa
Columbella Nassariidae
Nassarius
Tritia
llyanassa Buccinidae
Benn^ius (Jumalaj
Voluiopsius
Pyrulofusus
Colus
Plicifusus
Neptunea
Siphonalia
Pallia
"Canlharus"
Buccinum
Volulharpa
Macron
Chau vetia Meiongenidae
Melon^ena
Syrinx
Busycon
Hemifusus Fasciolariidae
Leucozonia
Peristernia
Fasciolaria
Pleuropluca
Fusinus
Troschelia Voiutacea
Voiulidae
Valuta
Alciihae
Mela
Cvniha
Cymbiala Margineliidae
Persicula
Marginella
Prunum Cancellariidae
Cancellaria
Admeie Vasidae
Vasurri Mitridae
Sirigaiella
A trim it ra Turbineilidae
Turbinella IXancus I Olividae
Ancilla
Olivella
Oliva
No. Species With Pelagic Larvae
No. Species With Non-pelagic Larvae
I
5 I
I
2
II
2 9 1
4 I I
2 8 I I I
I I
3 1
2 I
3 2 2 I
Reference
18.37,83
15.43,63,75,83 26,62,76 26,83 30,50.55.85
XX
61
7
74
25
6
30
ll,34,xx
II
49
6,15,24,26,43,45,49,63,83
30,39,47
72 6,63
6,25.54.78
4.6
82.85
70
43,72
3. 1 7.30.4 1 .42.45.63.79.83.92.93
3,5
79
21.30,50,82
30,85
22,32
30,82,84,xx
50
6,30,40
81
48
XX
30,84 30 14 30
35.45,71 36,6! 45.7l,xx 6
26,49,75
X
26,45.xx 45.75 6.14.43 30
45,80
33
6,20,38.88
51
9,45
43 43 26
43 82
26
26.66 16
26
63
6.30,53,67
65
X — E. Allison Kay, personal communication
113
velopment (62% compared to our 72%). Thorson's reasons for believing "that the species with a non-pelagic development predominate more in available data than they do in na- ture" are 1) these species have egg capsules which are large, conspicuous, and easy to dis- cover; 2) they tend to be discovered more often with their capsules than do species with pelagic development because they have a longer spawning season; 3) the capsules are eas- ier to identify to species and 4) his experience at the Canary Islands and in Thailand in- dicates "that most species with pelagic development there will reproduce in the hottest season of the year," whereas "biologists tend to make expeditions to such places at the cooler times of the year." Correction for these biases would lower Thorson's entire gradient of pelagic vs. non-pelagic development, except for the Arctic, where we have seen no evidence to indicate the existence of pelagic development among stenoglossans; thus the slope of the gradient probably would be increased from high to mid-latitudes. We would not, however, expect the slope to be changed much from mid- to low latitudes by corrections for any of the sources of bias suggested by Thorson, except his last one, which would, in theory, result in some steepening.
SELECTIVE ADVANTAGE OF NON-PELAGIC LARVAL DEVELOPMENT
The apparent predominance of non-pelagic development in the Stenoglossa has ne- cessitated a more detailed review of early development in this group (Table 1). The mode of larval development in the Stenoglossa seems generally to follow phyletic lines, regard- less of latitude or climatic conditions (beginning with the Buccinidae pelagic development is almost unknown). Exceptions include the Nassariidae, in which pelagic development is clearly predominant and the Mitridae, whose wide distribution in the Indo-west Pacific (Cernohorsky. 1965) suggests that the pelagic mode of development predominates. We cannot explain these apparent inconsistencies on the basis of our data.
Thorson (1950) argued that pelagic development is disadvantageous in the Arctic be- cause the period of rich plankton production on which most pelagic larvae depend for food is too short. For the lower latitudes, where both modes of development are practical, the problem remains.
Garstang (1928) and Thorson (1950) showed that pelagic development permits rapid dispersal, repopulation of depleted areas, and establishment of dense populations when the larvae encounter optimal conditions. By contrast, non-pelagic larvae tend to remain in established optimal situations, are not as numerous as pelagic larvae, and are provided with protection and a large food supply by parental brooding. This mode inhibits rapid dispersal, repopulation of depleted areas, and short-term establishment of dense popu- lations.
There is little information on the advantages of the various modes of larval devel- opment to marine prosobranchs and other marine invertebrates of shallow waters. Thus, the selective advantage of non-pelagic larval development in the stenoglossans is not clearly understood. However, most stenoglossans are carnivorous and, therefore, occupy relatively high trophic levels in their ecosystems. It seems reasonable to suggest that these animals are probably food-limited. Thus, it may be more advantageous for stenoglossans to use their energy in producing relatively few, non-pelagic young that can utilize "proved" local food resources, than to adopt the alternative strategy of producing vast numbers of highly vagile young that must find suitable conditions to insure survival.
ACKNOWLEDGMENTS
This report is based in part on a thesis submitted by the senior author to Florida State University in partial fultiliment of the requirements for the Master of Science degree. Dr. Harry W. Weils directed the thesis research. Drs. Joseph Rosewater and Harold A. Rehder. Division of Mollusks. U. S. National Museum of Natural His- tory, offered constructive ideas and suggestions. Mr. Anthony D'Attilio re-drafted the original illustrations.
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1928. The marine Mollusca of the Persian Gulf, Gulf of Oman and North Arabian Sea . . . addenda, corrigenda, and emendanda. Proc. Malac. Soc. London 18: 93-117.
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1898. Notes on a collection of marine shells from Lively Id., Falklands, with a list of species. J. Conch. 9:97-105.
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1878. Catalogue of the West Indian shells in the collection of Dr. CM. Poulsen. Bianco Luno, Co- penhagen. 16p.
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1957. Studies on the egg masses and larval development of some prosobranchs from the Gulf of Man- nar and Palk Bay. Proc. Indian Acad. Sci. 46: 170-228.
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1950. Spawning and development of some Hawaiian marine gastropods. Pacific Sci. 4: 75-1 15.
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Dept. of Marine Invertebrates, Natural History Museum, P.O. Box 1390, San Diego, California, 92112, and Environmental Oceanographic Research Program, National Marine Fisheries Service, Washington, D. C.
I
S-Aifi'S
MUS. COMP. 200L. LIBRARY
HARVARD UNIVERSITY.
A MARINE INVERTEBRATE FAUNULE FROM THE LINDAVISTA FORMATION, SAN DIEGO, CALIFORNIA
GEORGE L. KENNEDY
TRANSACTIONS
OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
VOL. 17, NO. 10 28 MARCH 1973
I
A MARINE INVERTEBRATE FAUNULE FROM THE LINDAVISTA FORMATION, SAN DIEGO, CALIFORNIA
GEORGE L. KENNEDY
ABSTRACT.— A small mainly molluscan invertebrate fauna, dominated by the Pismo clam Tivela stulto- rum (Mawe), occurs in the reportedly unfossiliferous Lindavista Formation on the Linda Vista Terrace (at an altitude of 130-140 m) east of Murphy Canyon, city of San Diego, San Diego County, California. The faunule is suggestive of two habitats, an exposed open coast sandy beach, and a cobble or rocky-bot- tom, both at littoral or shallow adlittoral depths. The age of the Lindavista Formation may either be late Pliocene or early Pleistocene on the basis of the fauna, which contains the extinct species Area sisquo- censis Reinhart and Pecten helliis (Conrad). Because of the fewer tectonic-related events experienced by the Lindavista Formation than by the unconformably underlying late Pliocene sediments, the formation may actually be early Pleistocene in age.
The presence of late Pleistocene marine fossils from the San Diego area has been well documented by numerous authors (see references in Kern, 1971; also Ellis, in Ellis and Lee, 1919; Berry, 1922; Valentine and Meade, 1961; Moore, 1968; Kern, Stump, and Dowlen, 1971; Bishop and Bishop, 1972). Fossils from the older Pleistocene(?) Lindavista Formation (called the Sweitzer Formation by some authors) are unknown from the San Diego area, although Minch (1967: 1 170) has reported finding "poorly preserved casts" at one locality in the Lindavista Formation in the Tijuana-Rosarito Beach area of north- westernmost Baja California, Mexico. In August, 1971, Richard C. Schwenkmeyer of San Diego Mesa College located an exposure of fossiliferous beach sand containing numerous fragments and a few complete single valves of the Pismo clam Tivela stultorum (Mawe) in a new housing development east of Murphy Canyon in San Diego (Fig. 1). Mr. Schwenk- meyer kindly brought this discovery to my attention, and the results of the ensuing in- vestigation form the basis for this note.
THE LINDAVISTA FORMATION
The Lindavista Formation, named for exposures near the Lindavista railroad siding (Hanna, 1926: 218), consists of several meters of iron-red, moderately indurated dirty sand and pebble-cobble conglomerate. Along the eastward extent of the formation, the sandy facies interfingers with terrestrial gravels which are probably deltaic in origin. In addition, the formation is commonly characterized by pea-sized hematitic concretions on weath- ered surfaces (Hanna, 1926: pi. 23; Emery, 1950). The lithology at the fossil localities (see also Register of Localities) varies from a very modern-looking clean gray laminated beach sand to a fossiliferous conglomerate rich in heavy minerals (Fig. 2).
The Lindavista Formation blankets the Linda Vista Terrace, a broad and essentially planar, slightly westward sloping wave-cut surface extending from the present coastline nearly fifteen kilometers inland, where it terminates at the base of the foothills. Remnants of this formation are exposed on terraces from northernmost Baja California (Minch, 1967: 1157, 1170) to areas near Oceanside in San Diego County (Emery, 1950: 214, and pi. 29). The most prominent features of the Linda Vista Terrace are the three ancient beach ridges which approximately parallel the present coastline. These have been inter- preted as stillstands during the marine regression which followed cutting of the terrace (Peterson. 1970: 122). Marine sediment along the eastern margin of this wave-cut surface was deposited earlier than that toward the coast.
The history of Pliocene and Pleistocene sedimentation of the San Diego coastal plain has been summarized by Hertlein and Grant (1944) and by Peterson ( 1970). Two possible sea level stands have been postulated for the events in the formation of the Linda Vista
SAN DIEGO SOC. NAT. HIST, TRANS. 17(10); 119-128.28 MARCH 1973
120
Figure 1. Index map of San Diego area showing general position of fossil localities on east side of Murphy Canyon.
Terrace (Hertlein and Grant, 1944: 64-65). One is that after deposition of the uppermost San Diego beds, the region was elevated but remained sufficiently below wave base for wave erosion or sea floor scour to truncate the marine Pliocene and Eocene beds. The Lindavista Formation therefore represents distribution by ocean waves and near-shore currents of coarse material derived from the local clastic formations, or by stream erosion on older rocks in the mountainous areas to the east. The second possibility is that parts of the San Diego Formation were elevated slightly above sea level at the close of the dia- strophic movements which "inaugurated Sweitzer time." The soft nature of the San Diego beds resulted in their quick destruction by waves and subsequent reduction to a shallow submarine platform. However, formation of the Linda Vista Terrace may also have been the result of a relative subsidence of the coastal plain (or rise in sea level) with con-
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comitant transgression of a shallow sea. then followed by submarine erosion. Subsequent retreat of the sea (as evidenced by the beach ridges) and deposition of the offlap facies (deltaic and terrestrial clastic sediments) to the east culminated deposition of the terrace material.
Despite problems of reconstructing these earlier events, at least 150 meters of relative sea-level change and only minor deformation has occurred during and since the creation of the Linda Vista platform (Peterson, 1970: 122). West of the Rose Canyon Fault consid- erable tilting and uplift has occurred, although not to the extent as affects the late Plio- cene San Diego Formation underlying it (Moore, 1972: 1 16, fig. 3 [Structure contours on the base of the Lindavista Formation]). The Lindavista Formation to the south on San Diego Mesa is flat-lying and in slight angular unconformity with the underlying San Diego Formation which dips 6° to 8° to the south-southwest (Hertlein and Grant, 1944: 63 [as the Sweitzer Formation]).
AGE OF THE LINDAVISTA FORMATION
The age of the Lindavista Formation has been variously interpreted as late Pliocene to late Pleistocene. Originally Hanna (1926: 218) simply assigned his "Lindavista terrace material" to the Quaternary. Hertlein and Grant (1939: 71) considered their Sweitzer Formation (which equals the Lindavista Formation) to be younger than the Pliocene San Diego Formation and to be either late Pliocene or early Pleistocene in age. Milow and Ennis (1961: 28) called the "Lindavista Formation" upper Pleistocene, but they were re- ferring instead to deposits of topographically lower and younger terraces than the Linda Vista Terrace. Their combined Sweitzer Formation and an overlying unnamed Sandstone comprise the Lindavista Formation of current usage. Most recently Peterson (1970: 122) has assigned the Lindavista Formation to the middle Pleistocene because of its medial po- sition between the "Early Pleistocene?" higher greatly dissected Poway Terrace and the late Pleistocene lower terrace associated with the Bay Point Formation. Fossils collected from the Linda Vista Terrace (see below; also Fig. 3) indicate either a late Pliocene or early Pleistocene age for the formation. Because of the greater number of tectonic-related events experienced by the late Pliocene San Diego Formation (see above), the Lindavista Formation may actually be early Pleistocene in age. although further evidence is needed before any age determination can be substantiated.
FAUNA OF THE LINDAVISTA FORMATION
The fauna of the Lindavista Formation is essentially a modern one, with a few ex- ceptions. Two of these. Area sisquocensis Reinhart and Pecten belhis (Conrad), are known only from Pliocene and lower Pleistocene strata in California. Turritella gonostoma hemp- hilli Merriam, only questionably found in the Lindavista Formation, also occurs in upper Pliocene rocks in California. Tegula hemphilli Oldroyd occurs in both the upper Pliocene San Diego Formation, and the upper Pleistocene of Pacific Beach, San Diego. The re- maining molluscan species are all extant, but range back into the Pliocene. The barnacle Balanus pacipcus Pilsbry. also only doubtfully identified, is not positively known to occur in Pliocene or older rocks (ZuUo. 1969: 10). These fossils indicate either a late Pliocene or early Pleistocene age for the fauna.
The possibility that the fossils have been reworked from the Pliocene San Diego For- mation is slight, but cannot be discounted entirely. The Lindavista Formation in the vi- cinity of the fossil exposures unconformably overlies the Eocene Friars Formation and Stadium Conglomerate (Kennedy and Moore, 1971). Field investigations have revealed no outcrops of the San Diego Formation anywhere in the area (G. W. Moore, pers. com- mun.; Hertlein and Grant, 1944: 50). The closest exposures of Pliocene strata are all sev- eral kilometers distant, to the south on the south side of Mission Valley, and to the west in the vicinity of Mission Bay and on Mt. Soledad.
The following species were found in exposures of the Lindavista Formation on the east side of Murphy Canyon in San Diego. Nearly all the species are from one locality (SDSNH loc. 0325); numbers following the species name are the number of specimens (fragments in parentheses) collected from this locality, unless otherwise noted. For local-
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Figure 2. SDSNH locality 0329: Fossiliferous exposure on Santo Road, San Diego, showing heavy-mineral sand, cobble conglomerate, and fragmented valves of Tivela siullorum. Meterstick for scale.
ity data see Register of Localities.
Mollusca. Gastropoda: Diodora arnoldi McLean, 1966—3; Calliosloma spp.—{\\); Te^uhi hemphilli Old- royd, 1921—3(4); Tegula funebralis (Adams, 1855)— 2(6); Turritella sp. cf. T. gonostoma hemphilli Mer- riam, 1941— (6); Turriiella sp.— l(\)\ Crepidula spp.— (2); Crucibulutn spinosum? (Sov^erhy. 1824)— (1); Polinices recluzianus (Deshayes, 1839)— 1(?12); Acanthina spirata (Blainville, 1832)— (21); unidentified fragments— (3). Mollusca, Bivalvia: Yoldia cooperi Gabb, 1865— (1); Area sisquocensis Reinhart, 1937— (1); Oslrea sp.— (1); Pecten bellus (Conrad, 1857)— 1; "Pecten' spp.— (16); Anomia'} sp.— 1; Pododesmus sp.- (2); Cardita sp. aff. C affinis Sowerby, 1833-1 at loc. 0329; Lucinisca nuttalli (Conrad, 1837)-2(15); Tivela siullorum (Mawe, 1823)- 12, 1(15) at loc. 0321. (6) at loc. 0322, fragments not collected at Iocs. 0323 and 0324, (1) at loc. 0326, 3(10) at loc. 0329; Proloihacal sp.-(l) at loc. 0329; Pelricola carditoides (Con- rad. 1837)-(1): Spisula hemphilli (Dall, 1894)-(2); Tellind! sp.-(2); Maeoma nasuia'^. (Conrad, 1837)- (1); Zirfaea pilshryi Lowe, 1931-(6, ?2); Peniiella sp.-(?l), (4) at loc. 0326; unidentified fragments-(9). Annelida, Polychaeta: spionid worm burrows— 15 [in single Tegula funebralis]. Echinodermata, Ech- inoidea: echinoid spines— 8. Arthropoda, Crustacea (Cirripedia): Balanus sp. cf B. pacificus Pilsbry, 1916—1; Megabalanus sp.— 2; unidentified barnacle wall plates— 75 + .
PALEOECOLOGY
The fauna collected does not represent the remains of any single biotic community, but rather is a detrital death assemblage from several near shore marine habitats. Speci- mens have been derived mainly from two habitats: sandy beach and cobble or rocky-bot- tom.
An exposed open coast sandy beach habitat at littoral or adlittoral depths is strongly suggested by the great abundance of the Pismo clam Tivela stultorum, as well as by the presence of Spisula hemphilli. Donax gouldi, a common member of this habitat group was unexpectedly absent. Many specimens are quite fragmented (most post depositionally), but their as.sociation with the cobble conglomerate indicates either local transport before deposition, or mixing with an offlap regressive facies.
A cobble or rocky-bottom habitat is suggested by many of the species in the fauna, including those in the genera Diodora, Calliosloma, Tegula, Acanthina, Area, Cardita, Protothaca, Pelricola, Peniiella, Balanus, and Megabalanus. Most of the specimens are fragmentary and while the conglomeratic nature of the outcrop may have been similar to the paleosubstrate (see above), mixing and local transport are indicated here.
123
In addition to the above habitats, there are representatives of soft-bottom (sand and mud) habitats which could have occurred in shallow protected bays or offshore below the level of effective wave action. These include species of Turhtella, Polinices, Yoldia, Pecten, Lucinisca, Tellina, Macoma, and Zirfaea.
Most species are largely represented by only a relatively few fragments, and indicate at least local transport and mixing. The high degree of breakage may well be a con- sequence of the conglomeratic substrate and proximity to surf action.
Of the extant species represented in the fauna, only Cardita sp. aff. C. affinis does not occur today in the vicinity of San Diego. Cardita affinis occurs from Bahi'a de Pequefia (26° 12' N) on the outer coast of southern Baja California, throughout the Gulf of Cali- fornia, and south to northern Peru. Tiirritella sp. cf. T. gonostoma hemphilli, a relative of the living T. gonostoma s.s., which occurs today from the Gulf of California southward to Ecuador, also suggests warmer water. The remainder of the fauna suggests a water tem- perature comparable with that of the present Californian Province. There are no cold-wa- ter or strictly northern species in the fauna. The occurrence in Pleistocene sediments of both cooler water (Californian) and warmer water (Panamic) species cannot yet be satis- factorily explained.
Reconnaissance geology of the area of outcrop by George W. Moore (pers. comm.) indicates that the Lindavista Formation lies on the Eocene Friars Formation (soft sand- stone) directly north of the eroded edge of the overlying Eocene Stadium Conglomerate, the contact between the two Eocene formations trending northeasterly. A ridge of the more resistant southward dipping conglomerate seems to have stood slightly in relief dur- ing erosion of the wave-cut platform. The fossiliferous deposits of the Lindavista Forma- tion lie in an embayment etched into the poorly cemented Friars Formation directly north of a Pleistocene rocky headland of Stadium Conglomerate. This physiographic con- figuration may have been responsible for the accumulation of different habitat forms in the fauna. Subsequent deposition of an offlap facies (conglomerate and tight deltaic sandy claystone, never deposited to the west), protected the deposits from weathering and erosion which probably accounts for the general lack of fossils in the formation as a whole.
SYSTEMATIC NOTES
Mollusca: Gastropoda
Diodora arnoldi McLc'dn, 1966
Fig. 3c
Range— Crescent City, Del Norte County, California, to Isla San Martin, Baja Cali- fornia ( McLean, 1966:6).
Remarks.— This small keyhole limpet occurs exclusively in the sublittoral zone and is not uncommon on the undersides of rocks below a depth of 9 m (McLean, 1969: 13). Diodora arnoldi is also known from the upper Pliocene San Diego Formation from south- westernmost San Diego County (LACMIP loc. 305A).
Tegula hemphilli Oldroyd, 1921
Fig. 3 a,b
Remarks.— This extinct low spired Tegula was described from upper Pleistocene de- posits on the La JoUa Terrace at Pacific Beach, San Diego (Oldroyd, 1921: 115). It is also known to occur in the upper Pliocene San Diego Formation, where it is exposed on Tele- graph Canyon Road, east of the city of Chula Vista.
Tegula funebralis (Adams, 1855)
Fig. 3d
/?a/jge.— Vancouver Island, British Columbia, to central Baja California (McLean, 1969: 22).
Remarks.— This species occurs strictly intertidally and is abundant in rocky areas at
124
■•ifA
'^
%•
^oiP'
Figure 3. Fossils from the Lindavista Formation, a, b, Tegula heniphilli. SDSNH 15581, width 16.2 mm; c, Diodora amoldi. SDSNH 14886. length 9.1 mm; d. Tei^iiUi fiwehralls, SDSNH 14889, width 27.2 mm; e, Pecten hellus, SDSNH 13117, height 22 mm; f", Cardila sp. aff. C. affinis, SDSNH 16678, length 59 mm; g, Tivela stulto- rum, SDSNH 14887. length 78.7 mm; h, Megabalanus sp., SDSNH 14888, height 60 mm.
the midtide level (McLean, 1969: 22). Dead shells are retained in the intertidal zone by hermit crabs, which use them for their own protection. The columella of one specimen has been extensively bored by spionid worms.
MoUusca: Bivalvia
Area sisquocensis Reinhart, 1937
Remarks.— One fragment of this distinctive Pliocene and lower Pleistocene Area was found. This species, described from the Pliocene Careaga Formation, also occurs in the lower Pleistocene Santa Barbara Formation (Reinhart, 1943: 25), as well as in the upper
125
Pliocene San Diego Formation exposed in southwesternmost San Diego County (LAC- MIP Iocs. 305 and 305A).
Pecten bellus (Conrsid, 1857)
Fig. 3e
Remarks.— One small flat left valve referable to Pecten hellus has the apical angle, number of ribs, and muscle scar typical of the species. This characteristic middle to late Pliocene species also occurs in the lower Pleistocene Santa Barbara Formation (J. W. Val- entine, pers. commun.). Sixteen additional pectinid fragments remain unidentified.
Cardita sp. aff'. C. affinis Sowerby, 1833 Fig. 3f
Range— [oi C. affinis] Bahi'a de Pequena, and the Gulf of California south to north- ern Peru (Keen, 1958: 85; Olsson, 1961: 190).
Remarks.— One complete right valve differs from Recent specimens examined by its more central umbo, rounded anterior and posterior margins, and greater thickness, al- though these diff'erences may only be phenotypic. Cardita affinis occurs under rocks or in crevices intertidally and off'shore to a depth of 27 meters (Keen, 1971: 107). This is the only living species in the fauna of the Lindavista Formation that does not presently occur along the San Diego coastline.
Fossil occurrences of C. affinis are known only from the upper Pliocene and Pleisto- cene of the southern part of the Gulf of CaUfornia (Durham, 1950: 72; Hertlein, 1957: 62; Emerson and Hertlein, 1964: 341).
Tivela siultorum(Ma'^e, 1823)
Fig- 3g
Range.— Hsilf moon Bay, San Mateo County, California, to Bahia Magdalena, Baja California (Fitch, 1953:60).
Remarks.— This is the most abundant of any species found, and fragments and occa- sional complete valves were present at every locality in the area which produced fossils. No paired valves were found, and all appear to be detrital. A few specimens still exhibit faint coloration patterns. Many of the valves have been post-depositionally fragmented. Tivela stultorum usually occurs in the intertidal zone on flat sandy beaches on the open coast (exposed to the full force of the surO. or in channels leading into bays and estuaries (Fitch, 1953: 60).
Penitella sp. indet.
Remarks. —Se\er2i\ small specimens of a poorly preserved Penitella were removed from sandstone cobbles at two localities. The umbonal regions of all the specimens are too damaged for specific identification. Species of Penitella are commonly found in cob- bles in molluscan death assemblages, and usually represent intertidal or high inner sub- littoral zones on the open coast where wave action is strong and fine sedimentation does not occlude the siphonal openings.
Arthropoda: Crustacea Cirripedia
Remarks.— 0\er 75 fragments of barnacle wall plates were found at one locality. These, although mostly unidentified, represent several species belonging to both Balanus s.s. and Megahalanus (Fig. 3h). Numerous fragments were recovered from the con- glomeratic sandstone, but none were found attached to cobbles, nor were any bases found on any of the cobbles. A single opercular plate has been tentatively identified as Balanus sp. cf B. pacificus Pilsbry, a species not positively known from Pliocene or older rocks (Zullo, 1969: 10). Balanus pacificus occurs today from San Francisco, California, to north-
126
em Peru, and is common in Pleistocene deposits of California and northern Baja Califor- nia (Zullo, 1969: 10).
REGISTER OF LOCALITIES
►
All of the following localities are from the lower Pleistocene (?) Lindavista Formation from exposures on the Linda Vista Terrace east of Murphy Canyon in the city of San Diego, San Diego County. California. Most of the specimens were collected by me in September (Iocs. 0321-0326) and late November (loc. 0329), 1971. These localities are now mostly on private residential property. Specimens have been deposited in the Department of Invertebrate Paleontology in the San Diego Natural History Museum and bear its locality numbers.
Loc. 0321. Northwest trending bank facing southwest on east (back) side of residence at 5349 Jazmin Court. San Diego. Unconsolidated sand. Altitude 142 m. Approximate coordinates: 32° 49.7' N., 117° 5.6' W. Locality found by R. C. Schwenkmeyer.
Loc. 0322. West-facing bank at the northeast corner of the intersection of Sandia Place and Gabacho Drive (10810 Gabacho Drive), San Diego. Fossil fragments in gray laminated and cross-bedded non-indurated beach sand with occasional scattered pebbles. Approximate coordinates: 32° 49.8' N., 1 17° 5.8' W.
Loc. 0323. North-facing bank on south side of lot at 10805 Gabacho Drive (in cul-de-sac opposite Sandia Place). San Diego. Laminated gray unconsolidated beach sand overlain bv well-indurated fossiliferous con- glomeratic sandstone, which in turn is overlain by a terrestrial conglomeratic facies. Approximate coordinates: 32° 49.8' N., 117° 5.8' W.
Loc. 0324. East-west trending utilities ditch in south side of street along north side of 10825 Gabacho Drive, San Diego. Approximate coordinates: 32° 49.8' N., 117° 5.8' W.
Loc. 0325. North-facing bank on south side of residence at 10735 Montego Drive (in southeast corner of first cul-de-sac on Montego Drive west of El Noche Way), San Diego. Unconsolidated fossiliferous con- glomeratic sandstone. Altitude 131 m. Approximate coordinates: 32° 49.7' N., 117° 5.8' W. Locality found by G. W. Moore.
Loc. 0326. West-facing bank on east side of residence at 10735 Montego Drive (in southeast corner of first cul-de-sac on Montego Drive west of El Noche Way), San Diego. Approximate coordinates: 32° 49.7' N., 1I7°5.8' W.
Loc. 0329. Ninety-meter stretch along west-facing roadcut on east side of Santo Road, beginning approx- imately 35-40 meters north of intersection of Santo Road and Monte Negro Drive, San Diego. Fossiliferous len- ses mixed with black heavy-mineral sand and cobble conglomerate. Locality found by G. W. Moore.
ACKNOWLEDGEMENTS
I am grateful to Richard C. Schwenkmeyer (San Diego Mesa College) for bringing his specimens and local- ity to my attention. George W. Moore (USGS) extended many courtesies, including extensive data from his own field investigations, and constructive criticism of the manuscript. The molluscan identifications have been checked by J. G. Vedder (USGS). Arnold Ross (SDSNH) kindly identified the cirripeds, and read the manu- script. Figure 1 was prepared by Lanci Valentine (University of California at Davis).
LITERATURE CITED
Berry, S. S.
1 922. Fossil chitons of western North America. Proc. Calif Acad. Sci., ser. 4, 1 1 : 399-525.
Bishop, M. J., and S. J. Bishop
1972. New records of Pleistocene marine Mollusca from Pacific Beach, San Diego, California. Veliger. 15:6.
Durham, J. W.
1950. Megascopic paleontology and marine stratigraphy, 216 p. In 1940 E. W. Scripps cruise to the Gulf of California. Geol. Soc. Amer., Mem. 43.
Ellis, A. J., and C. H. Lee
1919. Geology and ground waters of the western part of San Diego County, California. U. S. Geol. Surv., Water-Supply Paper 446.
Emerson, W. K., and L. G. Hertlein
1964. Invertebrate megafossils of the Belvedere Expedition to the Gulf of California. Trans. San Diego Soc. Nat. Hist., 13: 333-368.
Emery, K. O.
1950. Ironstone concretions and beach ridges of San Diego County, California. Calif Jour. Mines Geol., 46:213-221.
Fitch. J. E.
1953. Common marine bivalves of California. Calif Dept. Fish Game. Mar. Fish. Br., Fish Bull. 90: 1-102.
Hanna, M. A.
1926. Geology of the La Jolia quadrangle. California. Univ. Calit: Publ. Geol. Sci.. 16: 188-247.
Hertlein, L. G.
1957. Pliocene and Pleistocene fossils from the southern portion of the Gulf of California. Bull. So. Calif. Acad. Sci.. 56: 57-75.
127
Hertlein, L. G.. and U. S. Grunt IV
1939. Geology and oil possibilities of southwestern San Diego County. Calif. Jour. Mines Geol.. 35: 57-78. 1944. The geology and paleontology,' of the marine Pliocene of San Diego. California. Part 1, geology. Mem. San Diego Soe. Nat. Hist., 2: 1-72.
Keen, A. M.
1958. Sea shells of tropical west America. Stanford Univ. Press, Stanford. 624 p.
1971. Sea shells of tropical west America [second edition], Stanford Univ. Press, Stanford. 1064 p.
Kennedy, M. P., and G. W. Moore
1971. Stratigraphic relations of Upper Cretaceous and Eocene formations, San Diego coastal area, Califor- nia. Amer. Assoc. Petrol. Geol. Bull., 55: 709-722.
Kern. J. P.
1971. Paleoenvironmental analysis of a late Pleistocene estuary in southern California. Jour. Paleont 45- 810-823.
Kern. J. P.. T. E. Stump, and R. J. Dowlen
1971. An upper Pleistocene marine fauna from Mission Bay, San Diego. California. Trans. San Diego Soc. Nat. Hist., 16: 329-338.
McLean, J. H.
1966. A new genus of Fissurellidae and a new name for a misunderstood species of west American Diod- ora. Los Angeles Co. Mus. Contrib. Sci., 100: 1-8.
1969. Marine shells of southern California. Los Angeles Co. Mus. Nat. Hist, Sci. ser. 24, Zool. 11: 1-104. Milow, E. D., and D. B. Ennis
1961. Guide to geologic field trip of southwestern San Diego County, p. 23-43. In B. E. Thomas, ed.. Guidebook for field trips [57th Ann. Meet. Cordilleran Sec, Geol. Soc. Amer.].
Minch. J. A.
1967. Stratigraphy and structure of the Tijuana-Rosarito Beach area, northwestern Baja California, Mex- ico. Geol. Soc. Amer., Bull. 78: 1155-1177.
Moore. E. J.
1968. Fossil moUusks of San Diego County. San Diego Soc. Nat. Hist., Occas. Paper 15.
Moore. G. W.
1972. Ofi"shore extension of the Rose Canyon Fault. San Diego, California, U. S. Geol. Surv., Prof Paper 800-C: 113-116.
Oldroyd, T. S.
1921. New Pleistocene mollusks from California. Nautilus, 34: 1 14-1 16.
Olsson. A. A.
1961. Mollusks of the tropica! eastern Pacific particularly from the southern half of the Panamic-Pacific faunal province (Panama to Peru). Panamic-Pacific Pelecypoda. Paleont. Res. Inst.. Ithaca (New York). 574 p.
Peterson. G. L.
1970. Quaternary deformation of the San Diego area, southwestern California, p. 120-126. In E. C. Allison, et al, eds.. Pacific slope geology of northern Baja California and adjacent Aha California. [Geological guidebook for 1970 fall field trip. Pacific sees. AAPG. SEPM. and SEG].
Reinhart. P. W.
1943. Mesozoic and Cenozoic Arcidae from the Pacific slope of North America. Geol. Soc. Amer.. Spec. Paper no. 47.
Valentine. J. W.. and R. F. Meade
1961. Californian Pleistocene paleotemperatures. Univ. Calif Publ. Geol. Sci., 40: 1-45. Zullo, V. A.
1969. Thoracic Cirripedia of the San Diego Formation. San Diego County. California. Los Angeles Co. Mus. Contrib. Sci.. 159: 1-25.
Department of Geology, University of California, Davis, California 95616
S-/\)P^-S
MUS. COMP. ZOOL LIBRARY
HARVARD UNIVERSITY
POST-BATHOLITHIC GEOLOGY OF THE JACUMBA AREA, SOUTHEASTERN SAN DIEGO COUNTY, CALIFORNIA
JOHN A. MINCH AND PATRICK L. ABBOTT
TRANSACTIONS
OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
VOL. 17, NO. 11 10 APRIL 1973
POST-BATHOLITHIC GEOLOGY OF THE JACUMBA AREA, SOUTHEASTERN SAN DIEGO COUNTY, CALIFORNIA
JOHN A. MINCH AND PATRICK L. ABBOTT
ABSTRACT.— The post-batholithic history of the Peninsular Range is documented by sparse exposures of fluvial and volcanic rocks in widely separated areas. The Jacumba Valley outcrops present one of the most complete stratigraphic records in the range.
The intial erosion surface upon the Southern California Batholith probably formed in the Late Cre- taceous. This surface was fairly deeply weathered as was the earliest granitic gravel deposited upon it. Clasts resembling those of the Table Mountain Gravels were transported across the Jacumba area to the Pacific Coastal region, where they appear in the Cabrillo Formation of Late Cretaceous age. Eocene "Poway-type" gravel was transported acro.ss an essentially parallel surface just south of Jacumba Valley near La Rumorosa. Erosion partially removed and reworked the gravel until Early Miocene outpourings of basalt and pyroclastic debris filled in much of the Jacumba Valley area. The first basalt flows from eruptive centers within the valley were followed by faulting and the deposition of andesitic pyroclastic and lahar depos- its. The source of this andesite may have been the plug-like masses at Round Mountain and Jade Bench- mark. Continued faulting ofl'set the volcanic rocks before the eruption of a second series of basalt flows which covered the andesite in the northeast and east portions of the valley. Intermittent erosion within the volcanic sequence is evidenced by fluvial and eolian volcaniclastic deposits. Post-volcanic faulting elevated the Penin- sular Range and accelerated erosion to produce the present topography.
The Jacumba Valley area is located at the crest of the Peninsular Range and straddles the Mexico-United States boundary. Interstate 8 and the San Diego and Arizona Eastern Railroad pass through the valley between San Diego and the Imperial Valley. Rainfall is hght resulting in sparse vegetation and excellent outcrops. Field work for this report was accomplished in the fall of 1971 and spring of 1972 in conjunction with a field geology class at California State University, San Diego.
The first account of the post-batholithic geology of Jacumba Valley was by Fairbanks (1893), who indicated the presence of the gravels and volcanics at the crest of the Peninsular Range. Miller (1935a) followed with a brief description of the rocks and included specula- tions on their former widespread extent, exotic origin, and Miocene age.
In the late 1940s and early 1950s field classes from San Diego State College used the area for reconnaissance mapping exercises. These were compiled as map sheet 23 (Brooks and Roberts, 1954) in Bulletin 170 of the California Division of Mines and Geology. Ja- cumba Valley remains an excellent area for students to map in a terrane exposing a variety of eruptive features resting on sedimentary, plutonic, and metamorphic rocks.
Gastil and Bushee ( 1 96 1 ) and Weber ( 1 963 ) briefly mention the valley. Hawkins ( 1 970) provided a detailed analysis of the chemistry of the volcanic rocks in the valley and tied them into the over-all picture of sea-floor spreading in Southern Cahfornia. Minch (1971) described the Table Mountain Formation and indicated its nonlocal origin.
BASEMENT ROCKS
The crystalline rocks flooring the valley have been mapped as two separate units (We- ber, 1963). The older mass is comprised of metamorphic rocks mixed with granodiorite, diorite, and pegmatites. These metasedimentary rocks are dominated by the quartz- and mica-rich Julian Schist, with minor amounts of gneiss and quartzite and occasional pods of marble. These are cut by abundant pegmatites and plutonic bodies.
The younger plutonics of the Southern California Batholith are here composed mostly of quartz diorite along with granodiorite and minor pods of gabbro.
TABLE MOUNTAIN GRAVELS The Table Mountain Gravels are light yellow-brown, moderately bedded, fairly well-
SANDIEGOSOC. NAT. HIST. TRANS. 1 7( 1 1): 129-136, 10 APRIL 1973
130
sorted, very friable, medium to coarse-grained sandstones and conglomeratic sandstones which crop out in and near Jacumba Valley. In addition to local granitic clasts they contain clasts of low-grade green metavolcanic and metasedimentary rocks and quartzites that are not found locally.
Miller (1935a: 138) defined the Table Mountain Formation from exposures at Table Mountain 7 km northeast of Jacumba as: "Moderately consolidated deposits of yellowish to reddish-brown gravels and sands. Various kinds of pre-Cretaceous crystalline rock frag- ments occur in the formation . . . These sediments are rather variable in character, crudely stratified, and gently dipping."
Several authors have indicated the exotic nature of these gravels found high in the Pen- insular Range (Fairbanks, 1893; Brooks and Roberts, 1954; Weber, 1963). Brooks and Rob- erts (1954) compare the clasts to the Santiago Peak Volcanics of western San Diego County: "They contain fragments of dacites and other aphanitic rocks that show strong similarities to the Jurassic?Santiago Peak Volcanics of western San Diego County. These gravels are partially interbedded with and principally overlain by other volcanic rocks."
DISTRIBUTION. -The Table Mountain Gravels crop out on the erosion surface in a belt about 10 km wide and 25 km long that lies roughly parallel to the axis of the Peninsular Range. They are the remnants of an extensive fluvial deposit. In the Jacumba area they stretch another 5 km down the frontal scarp of the range. The principal outcrops are in and around Jacumba Valley and in the area just west of La Rumorosa in Baja California. The small isolated patches of the gravels which occur at lower elevations on the frontal scarp of the range are the easternmost exposures.
The best exposures of the Table Mountain Gravels are in the area of Jacumba Valley where the Jacumba Volcanics form a resistant cap above the gravels (Fig. 1). A typical section measured on a flat-topped hill just north of Jacumba in the northwest corner of Sec. 5, T 18 S, R 8 E consists of 75 m of interbedded light yellow-brown, moderately to thickly bedded, very friable, medium- to coarse-grained sandstone and Vi to 1 m thick beds of conglomeratic sandstone. The sandstones within the Table Mountain Formation are sheet-wash to fluvially deposited, plutonic lithic arkose. The framework grains are very angular, poorly to very poorly sorted, mineralogically immature, and are cemented by poikilotopic, very coarsely crystalline calcite where unleached. Common grains include both fresh and heavily sericitized plagioclase and orthoclase, polycrystalline quartz, schist and plutonic rock fragments along with hornblende, biotite, muscovite, and other acces- sory minerals.
The gravel-sized clasts are subangular to subrounded and average 2.5 to 5 cm in di- ameter with clasts commonly to 10 cm and rarely to 30 cm. Fifty percent of the clasts are extraregional, low-grade, green metavolcanic and metasedimentary rocks. Other signifi- cant components of these gravels are quartzites and resistant sandstones (25%), and local granitic and gneissic basement rocks (12%). The thickness of the gravels is quite variable, ranging from a thin mantle on the surface to greater than 75 m. Most exposures are less than 30 m in thickness.
Other good exposures of these gravels occur on the northeast side of Jacumba Peak (N. Center Sec. 7, T 18 S, R 8 E), on Table Mountain (T 17 S, R 8 E), and in Myer Valley (NE '/4, Sec. 26, T 17 S, R 19 E) about halfway down the frontal scarp.
In the Jacumba area the Table Mountain Gravels seem to have been highly eroded before the deposition of the Jacumba Volcanics. This is evident because the basalts and breccias have an irregular basal contact which, in one case, rests on 75 m of gravel at one end of a hill but sits on the granitic erosion surface 120 m lower in altitude at the other end of the hill.
AGE. The Table Mountain Gravels are certainly older than the 18.5 m.y. Jacumba Volcanics which overlie them, and they are younger than the rocks of the Peninsular Range Batholith upon which they rest (90-105 m.y., Bushee et al., 1963; cooling age of 65- 80 m.y., R. G. Gastil, pers. comm.). They were deeply eroded before the deposition of the Jacumba Volcanics, suggesting that they may be significantly older than the Miocene vol- canics.
In the San Diego coastal area the conglomerate of the Upper Cretaceous Cabrillo
131
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to massive to scoriaceous Basa It d i kes Cinder agglomerate; baked reddish cinders
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Figure 1. GENERALIZED COLUMNAR SECTION
Formation (Kennedy and Moore, 1971) contains a small percentage of black to blue-gray quartzite, light colored quartzite, and chert pebbles, and several types of metavolcanic clasts not associated with the local basement. These clasts are not found in the locally de- rived gravel of the underlying Lusardi Formation, indicating that they are extra-region- ally derived clasts. These exotic clast types are also found in the Table Mountain Forma- tion.
The presence of the extra-regional clasts in the Cabrillo Formation, which has been dated as Maestrichtian (Kennedy and Moore, 1971), suggests a relation to the Table Mountain Gravels, which in turn suggests that the two formations might be the same age. If so, this would place the initial deposition of the gravels in the Late Cretaceous.
I
JACUMBA VOLCANICS
The Jacumba Volcanics were defined by Miller (1935a: 138-139) for "...the exten- sive rocks which are excellently exposed in the several areas north to east of Jacumba . . . Some volcanic breccias or pyroclastics here occur toward the bottom of the lava beds." In the present report the Jacumba Volcanics are subdivided into three basic units. They are: (1) basalt flows and cinder-cone deposits, (2) basaltic-andesite plugs, and (3) andesite breccia, lahar deposits, conglomerate, and volcaniclastic sandstone.
The same authors who discussed the Table Mountain Gravels also generally dis- cussed the Jacumba Volcanics (Fairbanks, 1893; Miller, 1935a, b; Brooks and Roberts,
132
1954; Gastil and Bushee, 1961; and Weber, 1963). In addition, Hawkins (1970) discussed the petrochemistry of the volcanics and cited a K/Ar whole rock date of 18.7 ±1.3 m.y. for the lower part of the basalt sequence.
The Jacumba Volcanics form a 20 by 55 km belt of outcrops parallel to the axis of the Peninsular Range. However, the principal areas of outcrop are in a narrow belt 5 to 10 km wide by 55 km long on and along the frontal scarp of the range, with the majority of the outcrops near the base of the scarp. The Jacumba Volcanics also crop out in and around Jacumba Valley.
The basalt flows are the most extensive part of this unit, with outcrops over most of the valley. The andesite breccia, lahar deposits, and volcaniclastic sandstone are as exten- sive but more limited in outcrop. Remnants of at least five cinder cones and two promi- nent hypersthene andesite plugs are exposed in the valley.
FLOWS.-The lavas consist of up to 40 meters of gray to dark gray, platy to massive, vesicular olivine basalt and basaltic andesite. The basalt flows crop out at the base and at the top of the volcanic sequence. As many as five or six flow units may be represented in any given outcrop. These flow units tend to be massive in their upper portions but exhibit platy jointing due to flow shearing at their bases or where they abut other rocks (see Hawkins, 1970, for detailed chemical description).
DIKES AND CINDER CONES.-Squaw Tit is an excellent example of one of several prominent dikes exposed on Table Mountain (Map-Fig.2). This dike system appears to have partially followed a northwest-trending fracture system. The basalt in these dikes ranges from a dense gray-green to dark gray, well-jointed olivine basalt to a scoriaceous ohvine basalt which appears to have been close to the surface of a vent represented by the spine of Squaw Tit. These dikes cut the lower basalt unit and may be the source for the upper basalt unit.
Associated with these dikes are at least two cinder cones. The oldest cinder cone is at the base of the section east of a fault on the southern side of Table Mountain. It is 75 to 90 m high and is well exposed as a result of quarrying operations. The cinders comprising the cone are red- to purple-brown, well sorted, thinly bedded, and tend to be lapilh to dust size with a small percentage of blocks and very few bombs. The upper 15 m of the cone has been altered by gasses to a yellow-brown color. Also deposited during this pyro- clastic episode is a thinly bedded cinder carpet up to 4.5 m thick, which appears to be thicker to the east and southeast of the cone, suggesting a paleowind direction similar to the present prevailing wind pattern. This cone may have been the source for the earlier basalt flows. A fault truncates its west side and moves the western portion right-laterally about 90-150 m.
Transitional lithologies occur where the first pyroclastic eruptives are mingled with the granitic wash mantling the Table Mountain Formation. Commonly found here are volcanic glass-cemented, spherical concretions of slightly granular, bimodal, very coarse- and very fine-grained, volcanic lithic arkose. The coarser mode contains numerous pluton- ic rock fragments along with microcline, orthoclase, and perthite from the surrounding highlands. The finer mode comprises idiomorphic volcanic plagioclase, relict shards, 1am- probolite, zircon, biotite, and apatite. The non-concretionary arenite in places contains montmorillonite formed from altered pyroclastics.
West of the major fault and interlayered with but partially overlying the earlier flows is a series of agglomerate and cinder deposits. These pyroclastics are distinguished from the earlier cone materials because they overlie the lower basalt, are coarser, lack sorting, and contain a large percentage of bombs and agglutinate material. Some of the bombs and blocks in this younger cone are up to 1.3 m in diameter, although most average 3 to 5 cm. Several basalt flow units appear to have issued from the base of the younger cone along the west and northwest side of Table Mountain. The cone morphology is not ob- vious as it has largely been destroyed or obscured by later deposits. Cinder and scoria de- posits suggestive of smaller eruptive centers are found on the east side of the border hill (VABM 3572), in a pit along Carrizo Gorge road just north of old Highway 80, in a pit east of Round Mountain and south of Interstate 8, and in the low hills north of the free- way and west of the Jacumba turnoff'. All have an abundance of calcite cement, and in the
133
eruptive center just south of the freeway the calcite percentage is so high that the cinders initially appear to lack a supporting framework.
ANDESITE PLUGS.-Round Mountain and the hill at Jade Benchmark (Map-Fig. 2) are plugs whose chemistry differs significantly from the other volcanic rocks in the valley (Hawkins, 1970). They contain significant percentages of hypersthene in place of the hornblende typical of the basalt flows. These plugs are largely intact and have typical on- ion-skin jointing and a bulbous dome-like structure. Both plugs contain xenoliths of gran- odiorite, quartz diorite, and schist from the basement rock.
The plugs are younger than at least that part of the andesite breccia sequence which they rest upon. No clear-cut evidence can be presented for their minimum age and they could be much younger than the lavas and andesites. Similar appearing plugs of Pliocene age (R. G. Gastil, pers. comm.) occur in other parts of the Peninsular Range near the in- ternational boundary.
ANDESITE BRECCIA, LAHAR DEPOSITS, CONGLOMERATE, AND SANDSTONE.-A hetero- geneous sequence of andesitic lahar deposits, breccia, conglomerate and sandstone form a significant portion of the Jacumba Volcanics. The andesites are up to 150 m thick in some localities and generally average 90 m thick over much of the area. The breccia appears to be the dominant form of the andesite, but other forms are more common locally. The in- tergradation of the component rock types and the presence of a heavy lag gravel over the andesite prevented the mapping of the individual andesitic rock units.
The best exposure of the andesite breccia is just east of the Table Mountain quarry in NE '/4, Sec. 35, T 17 S, R 8 E (Map-Fig. 2). There the breccia consists of red-brown to brown to gray massive hornblende andesite which has been intensely sheared, broken, and comminuted to form a flow breccia. No bedding or stratification can be discerned at the outcrop.
The andesite breccias grade into lahars (mudflows of volcanic detritus). In the vicin- ity of the Table Mountain quarry an approximately 9 m thick lahar deposit consists of a red-brown to brown, massive andesitic breccia with andesite and cinder particles ranging from dust to small boulder size. The complete lack of bedding and sorting coupled with monohthologic andesite fragments are characteristic of a lahar deposit. Intermittent flu- vial action has reworked the breccia and lahar deposits producing volcaniclastic con- glomerate and sandstone which occur throughout the section. These fluvial units resemble the breccia in clast composition, and they are distinguished by the presence of bedding and of increased sorting of the clasts. A typical sandstone exposed above the quarry on Hill 4089 (SW '/4, Sec. 26, T 17 S, R 8 E) is a very poorly sorted, very angular to subangu- lar, pebbly medium sandstone. This and similar sandstone beds are lithic arkoses and are loaded with volcanic rock fragments and extrusive euhedral minerals, while plutonic-de- rived sediment is usually absent.
Mixed plutonic-volcanic lithic arkoses are found between tuff's (below) and volcanic mudflows (above) on the south side of Round Mountain. This mixed-provenance lith- ology illustrates the intermittent nature of volcanic sedimentation that allowed inworking of granitic-derived debris.
Intercalated within the volcanic sequence west of Gray Mountain is a volcanic lithic arkose mass exhibiting 0.6 to 1.3 m thick planar-wedge sets of cross-laminae. These fine sandstone grains are mostly plagioclase, volcanic-rock fragments, hypersthene, horn- blende, and biotite that are moderately sorted, skewed toward the fines, and subrounded to subangular. The sedimentary structures, presence of abrasion, fine grain size, and best sorting in the valley all indicate an episode of reworking of volcanic sediment into eolian dunes.
The various units of the Jacumba Volcanics are considered to be of Early Miocene age. The K/Ar whole rock age date of 18.7 ±1.3 m.y. (Hawkins, 1970) for a basalt on Ja- cumba Peak corresponds with concordant hornblende and plagioclase dates of 18.5 ±0.9 m.y. and 18.6 ±0.8 m.y., respectively, obtained from a clast in the andesite breccia on Table Mountain (K/Ar laboratory CSUSD). Thus, the bulk of the Jacumba Volcanics were erupted in the Early Miocene.
134
STRUCTURE
The structure of the Jacumba area is dominated by a series of northwest-trending normal and reverse faults. Two east-trending faults bound the area on the north and south. Only a few northwest-trending faults could be traced beyond the east-trending faults.
The northwest-trending set of faults produces a horst and graben effect within the valley. Throws of up to 300 m are necessary to produce some of the observed features. The fault which bisects Table Mountain has approximately 90 to 150 m of right-lateral separation and 30 to 60 m of vertical separation. In many cases a fault which can be traced for some distance with certainty in the volcanic rocks is lost within a few feet in the granitic rocks. In other cases a single fault in the volcanic rocks splits into several seg- ments as it enters the granitic rocks.
An interesting feature noted along several large faults is the inclusion of a thin sliver of Table Mountain Formation in the fault zone. In a number of cases the presence of a fault was recognized by the thin strip of conglomerate between the granitic and the vol- canic rocks.
The two east-trending faults are primarily in granitic rocks and have helped erosion produce long linear valleys. The northern fault exhibits a 0.6 to 1.5 m shear zone along the north side of Table Mountain.
The structure in the Jacumba Valley closely parallels the regional structure of the northwest side of the Peninsular Range. The valley itself is directly along the projected trend of the Elsinore fault zone as it passes out of the main mountain mass near Banner Grade. The right-lateral separation on at least one fault in the Jacumba area may suggest that some of the displacement on the Elsinore is taken up by movement along its pro- jected trend in the Jacumba Valley area.
ACKNOWLEDGEMENT
We would like to thank George W. Moore for his helpful review of this manuscript.
LITERATURE CITED
Brooks, B., and E. Roberts
1954. Geology of the Jacumba area, San Diego and Imperial Counties. In. Jahns. R. H.. ed.. Geology of Southern California. Calif Div. Mines and Geology Bull. 170, map sheet 23.
Bushee, J., J. Holden. B. Geyer, and G. Gastil
1963. Lead-alpha dates for some basement rocks of southwestern California. Geol. Soc. Amer. Bull. 74: 803-806.
Fairbanks, H. W.
1893. Geology of San Diego County. Calif. State Mining Bur. Repl. 11: 76-120.
Gastil, G.. and J. Bushee
1961. Geology and geomorphology of eastern San Diego County, p. 8-22. In, Field trip guidebook, San Diego County. Geol. Soc. Amer. (Cordilleran Section) 57th Ann. Mtg.
Hawkins, J. W.
1970. Petrology and possible tectonic significance of late Cenozoic volcanic rocks, southern California and Baja California. Geol. Soc. Amer. Bull. 81: 3323-3338.
Kennedy, M. P.. and G. W. Moore
1971. Stratigraphic relations of Upper Cretacious and Eocene formations, San Diego coastal area, Califor- nia. Amer. Assoc. Petrol. Geol. Bull. 55: 709-722.
Miller, W. J.
1935a. Geologic section across southern Peninsular Range of California. Calif Jour. Mines and Geology 31: 115-142.
1935b. Geomorphology of the southern Peninsular Range of California. Geol. Soc. Amer. Bull. 46: 1535- 1561.
Minch, J. A.
1970. Early Tertiary paleogeography of a portion of the northern Peninsular Range, p. 83-87. //;, Pacific slope geology of northern Baja California and adjacent Alta California. Amer. Assoc. Petrol. Geol. (Pacific Section) Fall Field Trip Guidebook.
i
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Weber. F. H.. Jr.
1963. Mines and mineral resources of San Diego County, California. Calif Div Mines and Geoloey Count) Rcpl. 3: 1-309.
Department of Geology, Saddleback College, Mission Viejo, California 92675, and De- partment of Geology, California State University, San Diego, California 92115.
s-m-s
MUS. COMP. ZOOL. LIBRARY
JUN221973
HARVARD UNWERS^TYi
REVISION OF THE CORAL-INHABITING BARNACLES (CIRRIPEDIA: BALANIDAE)
ARNOLD ROSS AND WILLIAM A. NEWMAN
TRANSACTIONS
OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
VOL. 17, NO. 12 20 APRIL 1973
Figure I. Boscia anglicum on Carvophvllia smiihii Stokes and Broderip: Eddystone, South Devon, England: British Museum (Nat. Hist.) 1904.6.27.13. British Museum photograph.
REVISION OF THE CORAL-INHABITING BARNACLES (CIRRIPEDIA: BALANIDAE)
ARNOLD ROSS AND WILLIAM A. NEWMAN
ABSTRACT.— The biogeography, growth, morphology and host specificity of all known taxa of coral-in- habiting barnacles in the Pyrgomatinae are reviewed. In addition to Pvri^oma and Cretisia. among which all of the species were previously divided, we resurrect five genera and propose Hoekia, Hiroa and Cantellius. These 10 genera fall into three groups: Boscia (cosmopolitan), Ceratoconcha (Pliocene in the eastern Pacific, Mio-Pliocene in the Mediterranean Basin, and as Miocene relicts in the western Atlantic), and Cantellius and its derivatives (Miocene to Recent in the Indo-west Pacific). The Pyrgomatinae are apparently poly- phyletic; Cantellius and possibly Boscia arose tYom different armatobalanid stocks, while Ceratoconcha arose from an indeterminate balanoid stock. Cantellius and Ceratoconcha first appeared in the Miocene during the break up of the Tethyan Sea and the initiation of faunal provincialism.
The reef coral community has been characterized by Cloud (1959: 387) as essentially a steady-state oasis of high population density, intense calcium metabolism, and complex nutrient cycling, generally surrounded by waters of relatively low nutrient and plankton content. Aside from interesting parallels with tropical rain forests and man-made mega- lopolises, Newell (1971: 2) argued that the organisms comprising the coral reef commu- nity are "superlatively coadapted." One of the remarkably coadapted animal groups is the coralliophilic pyrgomatines.
Barnacles comprising the Pyrgomatinae are obligatory symbionts or parasites prima- rily of scleractinian corals. They occur in all regions of the world that support major growths of hermatypic corals, and they have been found in sediments dating from the early Miocene. Modern pyrgomatines were probably recognized by naturalists in the 18th century, but the group did not receive serious attention until the middle of the 19th cen- tury. The present study is the first general revision on a world-wide basis.
HISTORICAL ACCOUNT
Studies on pyrgomatine cirripeds may be grouped into three periods. The work of Leach (1817, 1818, 1825), Sowerby (1823), Gray (1825, 1831), and many other con- chologists characterize the earliest period as one of describing new taxa and grouping these into a hierarchy.
The second period, covering about 70 years, began with the publication of Darwin's (1854) monograph of the Balanidae and Veruccidae. Darwin attempted to embody the best features of earlier studies; however, he chose not to follow the generic divisions pro- posed by Leach and Gray, and retained only Pyrgoma and Creusia, and the latter he as- signed subgeneric status. Leach and Gray had attempted to group a seemingly meager number of species into a maximum number of poorly defined genera. Consequently, Dar- win's conservative approach was generally accepted; and such caution has proved a deter- rent to unraveling the systematics of this group.
The third period began with the work of Annandale (1924), followed by Withers (1926, 1929), Hiro (1935, 1938), and Nilsson-Cantell (1938), and more recently, by Brooks and Ross (1960), Utinomi (1962, 1967), Baluk and Radwahski ( 1967a, 1967b, 1967c), and Ross and Newman (1969). Annandale, Hiro, and Nilsson-Cantell provided names for the majority of Darwinian numerical varieties, and they added considerably to our knowl- edge of the Indo-Pacific members of the subfamily.
Of the many classifications proposed for this group, the earliest were taxonomic rather than phylogenetic, except that of Gray (1825: 102), which was based on an ecologi- cal concept. The most promising classification was proposed recently by Baluk and Rad- wahski (1967c) who resurrected the generic groupings initiated by Leach, Gray and
SAN DIEGO SOC. NAT. HIST.. TRANS. 17(12): 137-174. 20 APRIL 1973
138
Sowerby, and proposed several new names. The present study somewhat revises and greatly extends their classification.
BIOGEOGRAPHY *"
Modern pyrgomatines occur in all regions of the world that support major growths of hermatypic corals. Fossils occur predominantly in the Tertiary and Pleistocene of the western Atlantic and the Mediterranean Basin (Withers, 1929: 2; Brooks and Ross, 1961: 326; Baluk and Radwahski, 1967c; Newman and Ladd, in press). The western Atlantic contains but a few morphologically primitive pyrgomatines, while the Indo-west Pacific has the greatest variety and abundance and the morphologically most advanced species. The disparity between these faunal realms may relate to the greater number of reef corals available as hosts in the Indo-Pacific, of which there are 80 genera and 500 species as compared to 20 genera and 65 species in the western Atlantic (Newell, 1971: 26), but the latter has also witnessed a general decline in the biota dating from the Miocene (Newell, 1971: 23).
Three major morphological groups of Pyrgomatinae are recognized in this paper {Ceratoconcha, Boscia and CantelUus and its derivatives), and these have interesting im- plications. The first and most generalized is the creusioid Ceratoconcha, which first ap- pears in sediments of lower Miocene age. Based on studies by Brooks and Ross (1961: 362), Baluk and Radwahski (1967c), and Newman and Ladd (in press), it is evident that during the Miocene Ceratoconcha was not only more diverse in terms of species than it is today, but also ranged throughout the tropical Atlantic and its eastern Pacific outpost, while it survives as a Miocene relict in the western Atlantic (Fig. 2). Ceratoconcha appar- ently never ranged into the Indo-Pacific, probably because communications between the Indian Ocean and the Mediterranean had ceased in early Miocene times (Ruggieri, 1967: 284) with the northward movement of the African land mass.
The Pliocene fauna in the Mediterranean Basin includes only C. costata (see Baluk and Radwahski, 1967c: 483; Moroni, 1967: 17); apparently no Pleistocene ceratocon- choids are found there. The short stratigraphic range of Ceratoconcha in the Mediterra- nean Basin is not surprising, because climatic cooling which had already begun in the Oligocene (Wells, 1956; Ekman, 1953), coupled with isolation (Ruggieri, 1967: 284), re- sulted in a decline in, if not total destruction of, the hermatypic corals and other tropical elements of the fauna.
The Mediterranean ceratoconchoids are probably western Atlantic derivatives de- spite the great distance separating these two regions. Numerous other invertebrates pres- ently have trans-Atlantic distribution patterns (Briggs, 1970), and apparently many of these animals have larvae that were transported eastward from the western Atlantic (Robertson, 1964: 21; ScheUema, 1971: 284).
Ceratoconcha was represented by at least five species in the western Atlantic in the early Miocene (Newman and Ladd, in press), and some time thereafter by a few species in the eastern Pacific. At least two species are found in Pliocene corals of the Imperial Formation of the Carrizo Creek and Coyote Mt. areas of southern California (Ross, un- publ.). There are no Pleistocene or living ceratoconchoids in the eastern Pacific. The west- ern Atlantic Pliocene fauna contains only preflorldanum: the Pleistocene fauna contains barbadensis, possibly prefJoridanum, and several undescribed species (Brooks and Ross, 1960: 362). The Recent western Atlantic contains two or possibly three species.
The second group, containing only the primitive pyrgomoid Boscia (Fig. 2), has been found in sediments of Pliocene age in the Mediterranean Basin (Baluk and Radwahski, 1967c: 483) and England (Darwin, 1854b; Withers, 1926). Pleistocene occurrences include Italy (Alessandri, 1906) and Japan (Sakakura, 1938). Although Sakakura reported the in- dividuals he found on an ahermatypic coral as anglicum, restudy of these may reveal that they represent either a new species or oulastreae (see Utinomi, 1967: 232), since anglicum appears to be restricted to the western Mediterranean and eastern Atlantic (Moyse, 1961: 384; Utinomi, 1967: 231; cf Rees, 1962: 412). Boscia occurs on hermatypic corals in the western Atlantic (madreporarum) and western Pacific (oulastreae), whereas in the eastern Atlantic and Mediterranean (anglicum) it settles only on ahermatypic corals. There are no
139
records of Boscia in the eastern Pacific.
The third group is wholly Indo-west Pacific with species ranging from the Red Sea to the Great Barrier Reef and to the Line Islands (Fig. 2 and 3). There are but two Miocene records for the eight genera in this group, but the specimens have not yet been identified (Newman and Ladd, in prep.). Nubia, Cantellius, and Savignium are found throughout the Indo-Pacific, but only Savignium ranges as far south as the Great Barrier Reef and as far east as the Line Islands. Pyrgoma, Creusia, and Hoekia range from eastern India to Ja- pan, although Hoekia has been reported from Mauritius (Ross and Newman, 1969). There is only one record for Hiroa, in the Caroline Islands.
From the foregoing, two provincial coral-barnacle faunas can be recognized, one centering in the Caribbean portion of the western Atlantic and the other in the Austra- lasian portion of the Indo-Pacific. Comparable biogeographic patterns have long been recognized in other invertebrates and in fishes (see Briggs, 1970). The coral barnacles were evolving when the continuity of the Tethyan Sea was being destroyed, ultimately leading to faunal provincialism. In light of the geological history of these regions and con- sidering the morphological features of these two groups, it is apparent that they devel- oped independently in the two regions from different balanoid ancestors. Boscia, which appears to be a third independent group, may owe its widespread distribution to its abil- ity to settle on deep-water ahermatypic corals.
GROWTH AND FORM
The early growth stages of pyrgomatines look much like those of ordinary balanids. It is in the later stages that their adaptations to an intracoralline hfe become evident. Knowledge of the larval stages is limited: Kolosvary (1950: 293) described typically bala- noid nauplii of Savignium milleporae and Moyse (1961: 371) described all larval stages of Boscia anglicum. Duerden (1904: 39) suggested that the cyprid bores through the living tissue of the polyp and that in the process of growth the skeletons of the two become fused.
Utinomi (1943: 16) followed the ontogeny of the earliest juveniles of Creusia indicum Annandale, and found that the juvenile does not initially attach to the coral skeleton but remains imbedded in the coral tissue. While the four plates making up the wall and the opercular valves are calcified, the cup-shaped basis of the juvenile is wholly membranous. Even after the basis calcifies there is a period when the juvenile remains free in the coral tissue before the basis and corallites come into contact and fuse. Moyse (1971: 127) noted similar relationships in Boscia anglicum.
Subsequent growth is rapid, especially laterally, so that the shell reaches essentially maximum diameter early in life. This is well illustrated by Hiro (1938, fig. 1 1 and 12). In general, the wall becomes proportionately less conical as its diameter and basal height in- crease, the aperture enlarging by diametric growth in four-plated forms, or by corrosion and cirral rasping in single-plated forms. In the scatter diagram plotted by Hiro (1938, fig. 12) for Creusia indicum, after the period when the basal height and shell width increase uniformly, width stabilizes while basal height continues to increase, as it must throughout the life of the barnacle. During the early period of rapid increase in width, the barnacle may rotate its position by as much as 90° (Baluk and Radwahski, 1967b, fig. 2, 1; New- man and Ladd, in press, pi. 2h).
Creusioids with well developed radii are commonly overgrown to some extent by the coral, and enlargment in both basal height and shell diameter requires breaking the over- growth along the sutures. Creusioids with radii indicated by simple sutures, and pyrgo- moids in general (except Boscia, see Moyse, 1971), have the ability to suppress coral skeleton deposition around the margin of the shell so that vertical growth can proceed without mechanical breakage. In some cases, the coral may lay down skeletal elements on the wall of the barnacle suggestive of normal septa, and the barnacle then takes on the appearance of a corallite (Duerden, 1904: 39); this is an unusual form of mimicry to say the least. In other cases, only coral tissue grows over the wall of the barnacle, and in Hoekia this tissue proliferates over the aperture where it is fed upon by the barnacle (Ross and Newman, 1969).
140
140° 120' 100° 60' 60* 40' 20' » 0° E ;0' 40° 60°
1 r
100° 120° 140° 160° E 160° W 160° 140°
-^
Caniellius
140° 120° 100° 80° 60° 40° 20° W 0° E 20° 40° 60°
100° 120° 140° 160° E 180° W 160° 140°
140° 120° 100°
60° 40° 20° W 0° E 20° 40° 60'
100° 120° 140° 160° E 180° * 160° 140°
60° E 160° W 160°
Figure 2. Distributional records for Nobia, Fyrgoma, Hiroa, Savignium, and Creusia. Data from same sources as Figure 3.
In specimens of Savignium crenatum that we have observed growing between low branches of the surface of Merulina ampliala, the rate of growth of the barnacle exceeds that of the coral so that the barnacle extends well above the general surface of the coral- lum. In most cases a thin layer of coral skeleton grows up onto the surface of the basis of the rapidly advancing barnacle, aiding in its support, but in some a fair proportion of the basis stands free of the coral. While it might appear that the barnacle's growth rate is sim- ply out of phase with that of the coral, there is adaptive value in growing in this manner. The barnacles are growing up between branches of the coral which will eventually fuse laterally at higher levels. If the barnacles simply kept pace with the growth of the surface, they would more than likely be buried.
Boscia anglicum grows in a similar manner, but on solitary ahermatypic corals, along the margin of the corallite (Fig. 1). In this position there is relatively little interference with the normal feeding mechanism of the coral. Established individuals frequently serve as sites for subsequent generations. Cloud (1959: 392) suggested that the barnacles re- place the coral polyps, and although this is certainly not true here, it may more frequently
141
IJO" 120' 100'
100° 80* 60' 40' 20° W 0° t 20° '0' 60
\2<y IW 160" E 180" * 160°
Figure 3. Distributional records for Caniellius. Hoekia, Ceratoconcha, Pyrgopsella, and Boscia. Circles and squares represent Recent records, triangles fossil records. Data based on specimens in the American Museum, San Diego Natural History Museum, Scripps Institution of Oceanography. Florida State Museum, British Mu- seum (Natural History), Museum of Comparative Zoology, Harvard University, and available literature.
142
be true in those corals having smaller caHces. Duerden (1904: 39) found that in Side- rastrea radians. Ceratoconcha fixes itself in the calicinal cavity, never on the ridges con- necting two calices and that the presence of the barnacle results in imperfections in the surrounding polyps.
The only pyrgromatine growing on the stinging hydrocoral Millepora is Savignium milleporae. It is not uncommon to find a thick-walled chimney of the host skeleton ele- vated about 5 mm above the general surface of the coral supporting the barnacle. The basis of the barnacle occupies the whole chimney, with the initial point of attachment es- sentially at the level of the surrounding colony. The top of the chimney is flush with the flat top of the barnacle. Evidently the general surface of the coral does not grow fast enough to accommodate the rapidly growing body chamber of the barnacle. Whether the barnacle is able to regulate the growth rate of the coral, so that the supporting chimney is formed, or the coral is simply reacting to the presence of a foreign object and attempting to bury it, has not been determined. Interestingly, Balamis stultus, the only other barnacle occurring on Millepora, likewise extends well above the general surface of the coral. It is also covered by a layer of coral skeleton, but it appears to be simply encrusted, rather than contained within a thick-walled chimney as is S. milleporae. Balanus stultus contin- ues to grow diametrically by fracturing the coral skeleton along the sutures in the wall. Thus in both cases the coral is reacting in ways that favor the diff'erent growth habits of the barnacles, and this suggests that these barnacles are exercising some control over the growth habits and defense mechanisms of the coral.
In general, shell color in the pyrgomatines is white. Boscia juveniles have a white shell, but with later growth the shell takes on a pinkish or pinkish-purple hue. Hoekia has a pinkish-purple shell, while that of Nobia is white and splotched with pink or purple. In Cantellius some species are all white, whereas in others the apical portion of the opercular plates is tinted purple. The shell in Savignium is commonly pinkish red, and in Pyrgoma it is a pale pink. Ceratoconcha is invariably white. While the basis is never pigmented, the exposed shell of most genera is. Consequently, there must be some adaptive or functional significance to these colors. Since the colors do not match those of their hosts, they appar- ently do not serve as protective coloration.
Generalized creusioids have well developed radii, and undergo diametric growth during the better part of their lives. The radii range in form from triangular to rectangu- lar, or they may be indicated externally simply by sutures. When the radii are triangular, the base of the isosceles triangle forms part of the apertural margin and indicates that the aperture has enlarged disproportionately to the total diameter of the shell. Rectangular radii indicate proportionate increments. Where radii are evidenced simply by sutures, di- ametric growth has all but terminated, and the total diameter of the wall can increase only by marginal increments. The aperture either remains the same or is enlarged by cor- rosion and (or) by the rasping eff'ect of cirral movement; such forms have eff'ectively reached the pyrgomoid level of organization.
The surface of the basis is commonly marked by longitudinal ribs, corresponding to the internal radiating ribs of the wall, and by transverse growth lines. The growth lines are generally very fine, ranging between 4 and 24 per mm (Newman and Ladd, in press), and are interrupted by discontinuities at more or less regular intervals (Baluk and Rad- wahski, 1967a, fig. 2; Newman and Ladd, in press, pi. l,b). The interruptions are fre- quently at intervals of 5 mm or so and probably correspond to the annual density bands in coral described by Knutson et al ( 1972: 270). This suggests that coral barnacles live for several years, which agrees with the age estimate given by Hiro (1938: 410). Unfortu- nately, the barnacles in which these bands have been observed are fossil forms that have been leached out of the coral so that the host species is unknown. With intact specimens, agreement between the bands in the coral and the barnacle probably could be deter- mined by the x-ray techniques employed by Knutson et al (1972), but such work remains to be done.
Coral barnacles do not live as long as their hosts, and eventually they become en- tombed. In some cases the opercular parts of the entombed barnacles are cemented in the position they occupied in life, while in others they have fallen into the body chamber. In
143
the first case the coral undoubtedly overwhelmed the barnacle while alive. This could be true in the second case, although it may be that the barnacle died before the coral over- grew it. In any event, the coral usually forms a "stopper," growing into the aperture a short distance, before attaining a normal growth pattern over the barnacle (Baluk and Radwahski, 1967c: 490).
To the best of our knowledge all pyrgomatines have solid walls, at least fundamen- tally. Some species develop parietal tubes where the longitudinal ribs on the interior of the wall become fused with the sheath, while others form tubes between external longitu- dinal ribs. In still others, where the sheath becomes fully fused to a much thickened wall, several rows of more or less regularly spaced tubes develop. In none of these cases are the tubes formed in the same way as in the tubiferous balanids (subgenera Balanus and Mega- halanus) where interlaminate figures can be observed in the longitudinal septa separating the inner and outer laminae of the wall.
The ontogenetic and phylogenetic development of tubiferous walls has been ana- lyzed in a number of cases (Costlow, 1956; Newman et al, 1967; Ross and Newman, 1967), but their function has only been a point of speculation. A few systematists have suggested applying the general engineering principle that, for a given amount of material, a properly designed tubiferous structure would be mechanically stronger than a solid one. If it were necessary for a barnacle to be economical in its use of calcium carbonate, then a tubiferous wall should be advantageous in high energy environments. Barnes et al (1972) tested the resistence of certain species to impaction and found that breakage occurred not in the plates themselves but at the sutures between them. They concluded that the strength of the plates generally exceeded the strength of the articulating joints. The nature of the articulation between the wall and calcareous basis is also of great importance (New- man et al, 1967: 170). These structural features are well developed in the pyrgomatines. However, wall strength in coral barnacles can hardly be related to withstanding impac- tion as in many free-living forms, but rather is related to the pressures required to sustain growth in an intracoralline habitat.
Considering the array and independent occurrences of tubiferous walls, and the sec- ondary modifications found in them, e.g. sealing off into chambers, secondarily filling with calcareous material, or filling with chitin during construction, one might look for some adaptive value other than simply strength. Ross (1970: 9) and Newman and Ross (1971) suggested that such adaptations might include defensive mechanisms against bo- rers, specifically against the drilling of gastropods. In this regard, Orton (1927: 653) noted that "oysters are frequently attacked and abandoned (by gastropods) . . . if either a cham- ber or loose horny layer is encountered . . ." It would be expected that free-living barn- acles, which are frequently attacked by gastropods, would also have developed defense mechanisms against them. However, in the pyrgomatines predation by borers has not been reported. Their tubiferous walls, then, developing in different ways in different members of the group, undoubtedly have some other function. Strength is probably the important one, but it is also likely that these tubes allow for physiological interactions be- tween the barnacle and its host. In many species the tubes are arranged so as to leave gaps around the margin of the shell, which appear to allow the uncalcified integument of the barnacle to come into intimate contact with the tissue of the coral. Moyse (1971) sugges- ted that the barnacle may receive metabolic substances from the host by this route. How- ever, we believe it more likely or important that these are the sites where physiological control of coral growth are initiated.
The opercular valves function to guard the aperture and range in form from wholly balanoid to highly modified. In Cantellius and Ceratoconcha. the two most generalized genera, the four-plated wall varies from high conic to virtually flat. Yet the valves are al- ways tall and typically balanoid. The same can be said of Boscia, except that it has a con- crescent shell. In these three genera the terga as well as the scuta occlude the aperture.
In the Savignium line (Fig. 5), the opercular valves are generally thin and fragile, and the wall is totally concrescent. The scuta are relatively elongate and the reduced terga be- come completely fused to them. Likewise, the aperture is elongate, and it is guarded primarily by the scuta. The epitome of modified valves is seen in Hoekia. However, it has
144
a minute orifice and tiiis is related to its wholly parasitic way of life (Ross and Newman, 1969).
In the Hiroa lineage the opercular valves tend to remain balanoid, although the scuta alone occlude the aperture. Modifications within the lineage include elongation and nar- rowing of the terga and reduction of articular margins on one hand {Hiroa, Pvrgoma), and broadening and concrescence on the other (Nobia, Creusia). In Hiroa- Pyrgoma the opercular plates are relatively thin and fragile while in Nobia-Creusia they are thick and massive. This disparity correlates to some extent with size, but the difference probably also relates to the amount of protection each requires from predators. Baluk and Rad- wahski ( 1967c: 463), with reference to Darwin's plate 13, fig. ld,(Fig.l2, c herein), misun- derstood the anatomical relationships between the opercular valves and the wall in Nobia, and concluded that the valves no longer guard the aperture. Apparently, they were not distinguishing between the scutal and tergal portions of the concrescent valves and thought that the occludent margins of the scutal portions were fused together and no longer functional.
In summary, cyprids of coral barnacles apparently first settle on coral tissue where they metamorphose into juveniles. A juvenile doesn't attach to the coral skeleton until af- ter the cup-shaped basis has become calcified. During this period, and to some extent af- ter attachment, the juvenile may undergo reorientation in relation to the host of as much as 90°. Unlike ordinary barnacles, subsequent growth is primarily through elongation of the basis rather than the wall. Species with radii generally undergo diametric growth and, in the process, frequently fracture the coral skeleton overgrowing them. Advanced species apparently gain a degree of control over coral tissue, and its ability to lay down new skele- ton. While barnacles live for several years, they eventually become entombed.
HOST SPECIFICITY
Gray (1825: 102) proposed the Pyrgomatidae to accommodate several balanoid gen- era peculiar to certain zoophytes; Pvrgoma and Creusia imbedded in scleractinian corals, Conopea in gorgonians and Acasta in sponges. The unification of these genera under one family was based primarily on comparable habitats.
Figure 4 summarizes available data on distribution of the various genera of Pyr- gomatinae among the scleractinian suborders. Of the ten genera all, except Pyrgopsella in sponges (not included in the figure) and Savignium milleporae on nine species of Mille- pora, occur exclusively on hermatypic and ahermatypic corals. Of these, seven genera oc- cur on Faviina, five on Fungiina, five on Astrocoeniina, four on Dendrophylliina, and two on Caryophylliina. Faviina then, with the greatest diversity of genera, supports the great- est diversity of coral barnacles. Caryophylliina, while nearly equal to Faviina in numbers of genera, supports the least. This is no doubt because Faviina, Fungiina, and Astrocoe- niina are hermatypic, while Dendrophylliina and Caryophylliina are ahermatypic with representatives ranging into deep water. Balanoids in general are shallow water organ- isms.
Only the cosmopolitan genus Boscia is known to inhabit all five scleractinian subor- ders and it is, as far as opercular valves are concerned, among the most generalized of the Pyrgomatinae. Hoekia, Pyrgoma, and Hiroa are each limited to but one scleractinian sub- order, and each is monotypic. Of these, the first two are among the more specialized members of the subfamily, Hoekia being the most specialized balanoid known. Hiroa on the other hand resides at the stem of the other higher forms {Creusia, Nobia, and Pyr- goma) which, between themselves share all five scleractinian suborders, with Nobia, a rel- atively highly modified form, occurring on four of them.
Ceratoconcha is one of the most generalized forms, yet it inhabits but two of the scle- ractinian suborders. In being an Atlantic genus, it has survived in a situation where coral diversity has declined since the Oligocene or Miocene (see Biogeography). The remaining generalized genus, Cantellius, stands at the stem of the Indo-Pacific members of the sub- family and is well represented on the three principal shallow water suborders, Faviina, Fungiina, and Astrocoeniina.
From the foregoing, what can be said of host specificity among Pyrgomatinae at the
145
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Figure 4. Distribution of genera of Pvrgomatinae among scleractinian coral suborders derived from the liter- ature. Space for each coral suborder is proportional to the total number of coral genera within each suborder; bar width indicates number of occurrences of barnacles within each suborder; bar height represents the number of coral genera on which the barnacles are known to occur.
scleractinian subordinal level? One might expect highly modified forms to be highly host specific, and for such extremes as Hoekia this is indeed the case. However, Nobia is among the most modified forms, yet it occurs on all scleractinian suborders except As- trocoeniina, while Hiroa, an intermediate in the transition between Cantellius and Creusia, has been found only on Astrocoeniina. Savignium and Creusia exploit mainly Fa- viina while Cantellius exploits mainly Fungiina and Astrocoeniina, but the division is not precise as there is considerable overlap among the three.
What then seems to be the situation as regards host specificity at the specific level? Hiro (1935: 23) found that in Tanabe Bay, Japan, ''A given species of Pyrgoma is prac- tically confined to a single species of coral, whereas the same variety of Creusia may be found on various kinds of coral." In 1938 he reported on his findings in the more tropical Palau Islands. While expanding the number of corals playing host to species of Pyrgoma (1938: 404), he again came to the same general conclusion (1938: 392). Presently, his statement holds best for the monotypic genera.
The suborder Faviina plays host to most of the genera of Pyrgomatinae. Of the Fa- viina, Pontes apparently has been selected most frequently as a host. Other balanids also have invaded Pontes, the Recent armatobalanid Balanus allium, the Pliocene to Recent armatobalanid Balanus durhami and the Miocene balanid Balanus duvergieri are notable. Growth on Pontes is independent of the growth of individual coral polyps and con-
146
sequently requires little specialization. This appears to us to be the reason why Porites plays host to a variety of barnacles. Millepora, on the other hand, does not, and one might suspect that this is due to its stinging ability.
In summary then— 1) the greatest diversity of Pyrgomatinae in terms of numbers of genera is found among hermatypic suborders, particularly Faviina and this is probably because balanids in general are shallow water organisms; 2) there are no marked differences between the occurrences of pyrgomoids and creusioids as a whole on the vari- ous suborders of scleractinian corals— in both groups Faviina is preferred, with scattered occurrences between the other scleractinian suborders; and 3) the rule (Hiro 1938: 408), that the more peculiar the morphological characteristics of species, the more rigid their host specificity, holds in a general way. The same rule holds only weakly when applied to barnacle genera and scleractinian suborders, for some relatively specialized genera, such as Nobia and Boscia, occur on a wide variety of corals and are notable exceptions.
ORIGIN AND EVOLUTION
The Pyrgomatinae are a well defined group (Baluk and Radwahski, 1967b: 465), but to what lineage of the Balaninae the subfamily owes its origin has not been resolved. Al- though the consensus is that the Pyrgomatinae are polyphyletic, only the broader outlines of their evolution have been elucidated (Withers, 1929: 564; 1935: 38; Hiro, 1938: 402, 412; Zullo, 1961: 72; 1967: 127; Baluk and Radwahski, 1967c: 500). Existing problems stem from a lack of critical data on fossil and Recent forms, as well as from Darwin's (1854) conservative handling of genera and species. His treatment of Creusia as a sub- genus of Pyrgoma has not been accepted by later workers. Also, his reluctance to recog- nize geographic populations of Creusia as species, even though a sample from a given locality showed markedly uniform characteristics (Darwin, 1854: 376), and the failure of subsequent workers to rectify this, resulted in a plethora of subspecific and in- frasubspecific taxa that make little sense biologically. Therefore, before looking into the origins of these barnacles relationships within the subfamily are discussed.
Pyrgoma. in the broad sense, contains the most highly evolved members of the Pyr- gomatmae (Darwm, 1854: 355, 375; Hiro, 1938: 402). Baluk and Radwahski (1967b: 691; 1967c; 486) revised Pyrgoma, dividing it into Pyrgomina ( = Megatrema of Utinomi, 1967: 232) and Pyrgoma with its subgenera Nobia and Daracia. We recognize somewhat similar groupings, with minor differences in the arrangement of species, but all at the generic level. The relationships of the genera are indicated in Figure 5.
Pyrgoma s. s., Nobia, Savignium, Hoekia, and Pyrgopsella are Indo-Pacific shallow- water pyrgomoids. Boscia is a cosmopolitan pyrgomoid, having both shallow and deep- water representatives. The Indo-Pacific pyrgomoids differ morphologically from Boscia in having highly modified opercular valves and in lacking paired fissures ('sutures') in the sheath; they can be derived readily from Indo-Pacific creusioids {Cantelliiis, Creusia, Hiroa), as will be discussed, but they cannot be derived readily from Boscia. We infer that Boscia has had a separate origin— that is, that the Pyrgomatinae are at the least diphyletic. In contrast, the Indo-Pacific pyrgomoids apparently are related through two major lines derived from different creusioid lineages. Hence, we infer that the pyrgomoid level of or- ganization has been achieved at least four times (Fig. 5).
Creusia, in the broad sense, contains the most generalized members of the Pyrgoma- tinae. Baluk and Radwahski (1967c: 484) attempted a modest revision oi Creusia, which they divided into the nominate subgenus and a new subgenus, Withersia. Their revision was based mainly on fossil forms, thereby considering only the Atlantic fauna and thus failed to come to grips with the Indo-Pacific Creusia spimdosa complex; and the natural groupings that exist within Creusia were overlooked. All of the Atlantic species, both liv- ing and fossil, form a natural unit for which the name Ceratoconcha is available. Cerato- concha has relatively unmodified balanoid opercular valves of a characteristic type that differ markedly in form from what would be considered generalized balanoid valves of the Indo-Pacific forms contained within our newly proposed genus Cantellius. This in- dicates that the generalized or primitive creusioids are not closely related and if the creu- sioids descended from a common balanoid stock, they did so independently in the
147
CREUSIA
NOBIA
PYRGOMA
BOSCIA
CANTELLIUS
CERATOCONCHA
®Z)V ^M
Figure 5. Diagram depicting inferred phylogenetic relationships within the Pyrgomatinae. The group or groups from which Boscni. Ceratoconcha. and Caniellius evolved remain unknown. The solid lines radiating from the orifice of the shell, shown in plan view, indicate relative position of the sutures separating the compartments; the dotted lines in Bosci'u indicate the position of the pseudoalae. Dotted lines on the opercular plates indicate a structures present in only a few species of that group.
Atlantic and the Indo-Pacific. Thus we set Ceratoconcha from the Atlantic apart and inde- pendent from the Indo-Pacific creusioid genus Caniellius, and consider the subfamily to be triphyletic (see Fig. 5).
Although Ceratoconcha has remained much the same throughout its history, the Indo-Pacific creusioids have undergone marked diversification. There is no fossil record to document the lineages leading to contemporary forms, but among Recent representatives there are sufficient forms upon which to draw inferences. First, there presently appears to be no reason to suggest that the Indo-Pacific creusioids are other than a natural group since they can be derived readily from one another. Caniellius is the most generalized and is envisaged as the stem from which the remaining genera evolved. Secondly, there are apparently two major lineages, one stemming from Hiroa, the other from Savignium;— that is, two parallel lines, each leading independently from Caniellius to pyrgomoid forms (Fig. 5). Pvrgopsella, occurring in sponges, appears to be an ofi'shoot of the Savignium- Hoekia line. The modifications that ensue in each line concern alterations in the form of the opercular valves and concrescence of the wall plates, presumably better adapting the barnacles to different host corals. Interestingly, the most modified form, Hoekia, has the most reduced wall plate, aperture, and opercular valves of any pyrgomoid. It has also modified its nutritional source, shifting from setose feeding to feeding directly on the tis- sues of the host coral (Ross and Newman, 1969: 255).
Baluk and Radwanski (1967c: 465) believed that Pyrgopsis annandalei Gruvel ( = P\rogopsella nom. nov., Zullo, 1967), dredged from 90m off the Andaman Islands, should not be assigned to the Pyrgomatinae because the basis is membranous. Gruvel (1907: 8) had three specimens, but the habitat and (or) actual relationship of the barnacle to the substratum were unknown. He inferred that the membranous elongate basis func- tioned as a peduncle or stalk, analogous to the fleshy stalk of Xenohalanus, by which the animal attached to the substratum. Indeed, Zullo (1967: 123) referred to Pvrgopsella as an "unusual pedunculate balanid." Recently, however. Resell (pers. comm., 1971) reported finding a new species of Pvrgopsella imbedded in a sponge from the Philippines, and we believe that this explains the peculiar anatomical structure of the genus. The mem- branous stalk is not a "peduncle" in the sense used by Gruvel, but rather it is an elongate basis comparable to and serving the same function as the elongate basis of other Pyr- gomatinae. In inhabiting sponges, rather than a coral, the basis is membranous rather than calcareous, analogous to the situation seen in Memhranohalanus also inhabiting sponges. The single plate making up the wall and the pyrgomoid valves suggest that Pvr- gopsella is an off-shoot of the coral-inhabiting pyrgomatines. Indeed the valves are similar to those of Savigniunh and it is from this genus that we infer it has evolved.
In summary then, the Pvrgomatinae are a diverse group of coral-inhabiting balanids. dominated by a central group of eight wholly Indo-Pacific genera stemming from Can-
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lellius, and flanked by the cosmopolitan genus Boscia and the Atlantic genus Cerato- concha. Cantellius, Boscia, and Ceratoconcha have rather generalized balanoid opercular valves, but there is no indication that one gave rise to the other. Rather it is inferred that they descended independently from balanoid ancestors, and therefore the subfamily is considered triphyletic. We can now ask from which balanines these three lines may have evolved.
There is ample evidence that the Pyrogomatinae have been derived from balanines; the rostrum overlaps the laterals, the opercular plates are balanoid, the labrum is notched, and the intromittant organ bears a basidorsal point. While the most primitive living balanid {Chelonibia) has eight plates making up the wall, it is apparently a special- ized survivor of an ancient stock that presumably gave rise to the more typical balanines. The vast majority of typical balanines have six plates making up the wall, and it has gen- erally been assumed that the Pyrgomatinae descended from some six-plated ancestor (Withers, 1929: 564; 1935: 38; Hiro, 1938: 402; Zullo, 1967: 127; Baluk and Radwahski, 1967c: 504). Withers (1935: 38) suggested that Balamis {Balanus) duvergieri (Alessandri) might be such a form, and Zullo (1961: 72) proposed the subgeneric name Hexacreusia for Balamis durhami, a species he thought also likely to be such a form.
Balanus duvergieri, with its tubiferous wall and basis, appears to belong to the sub- genus Balanus, where Withers placed it. The wall of all known pyrgomatines is solid; while tubes may be found in some species, they are formed between the sheath and the internal ribs or between external ribs of the wall and therefore are not homologous with the tubes of Balanus. All generalized pyrgomatines, except Boscia anglicum, have a solid basis. The opercular valves of 5. duvergieri are generalized, resembling those of Cantellius more than those of Boscia and Ceratoconcha, but this is no doubt simply because Cantel- lius has the most generalized valves of any of the pyrgomatines. In light of the differences in the wall between B. duvergieri and the Pyrgomatinae, and in light of the evidence indi- cating that the Pyrgomatinae had a solid-walled ancestry, we must agree with Baluk and Radwahski ( 1967c: 504) that B. duvergieri is not an ancestor of the Pyrgomatinae as Withers suggested, nor is it closely related to the stock from which the Pyrgomatinae must have been derived.
Balanus durhami appears closer than B. duvergieri to the stem hne of the Pyrgoma- tinae since it has a solid wall and basis, and since the opercular valves are superficially comparable. If 5. durhami had but four wall plates rather than six, would it then belong to the Pyrgomatinae, and if so, to which of the three major groups would it be assigned? It would belong to the Pyrgomatinae as presently defined, but it is not readily assignable to any one of the three existing divisions. The tergum, with broad spur and strongly developed depressor muscle crests, and the scutum, with a broadly developed adductor ridge descending from the occludent margin, differ markedly from the generalized types seen in the subfamily, so that B. durhami would have to be placed as a fourth and inde- pendent line. Although for different reasons, we agree with Baluk and Radwahski ( 1967c: 504) that B. durhami is not a surviving ancestor of the Pyrgomatinae. Yet it is much closer to what must have been the balanine stock from which one or more of the Pyrgomatinae lines were derived, and it is therefore necessary to look closely at the affinities of B. durhami.
Zullo (1961: 75) stated that B. durhami resembles species of the subgenus Armatoha- lanus but differs from them in having the anterior margin of cirrus III toothed rather than only cirrus IV, and he placed it in a new subgenus, Hexacreusia.^ However, when Zullo (1963: 590) described B. [Armatobalanus) nefrens from California, he noted that this spe- cies lacks hooks or spines on cirrus IV, as does B. {A.) oryza Broch from the southwest Pacific. Zullo (1967: 127) later noted that Darwin (1854) confused specimens of B. dur- hami with B. (A.) allium from the southwest Pacific. He stated that such species of Arma- tobalanus, as terebratus Darwin are so similar to B. durhami that it appears reasonable to assume that the armatobalanids were the ancestral stock from which the coral barnacles
'We wholly concur that Hexacreusia and Arniatohalaniis are similar, and in fact, except for the development of the scutal adductor ridge in the former, there are no diagnostic difi'erences between them. Rather than elevate Hexacreusia to generic rank as did Zullo, et al (1972: 72), we consider it synonymous with Annatobaluiuis. If Armatohalanus were raised to generic rank, it would be reasonable to consider //tn^/cref/.v/asubgenerically distinct.
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Figure 6. enhagen.
Cantellius pallidus on Fungia fungites (Linnaeus). Indo-west Pacific. Zoologisk Museum, Cop-
were derived.
Darwin (1854: 282), Hiro (1938: 402), and Zullo (1967: 127) looked to Armatoba- lanus as the stem line from which the Pyrgomatinae evolved. Members of the subgenus are found in both the Atlantic and the Indo-Pacific, some occur exclusively on corals, and one is known from the late Miocene of the United States (Ross, 1965: 337). There is a fair diversity of opercular valves, and in general these bear a closer resemblance to those of Cantellius than to those of Boscia or Ceratoconcha.. If the lines within the Pyrgomatinae have in fact evolved three times, it seems likely that at least the Indo-Pacific Cantellius and its derivatives and perhaps Boscia have an Armatobalanus ancestry. The affinities of Ceratoconcha are still too obscure to conjecture (see Newman and Ladd, in press).
SYSTEMATICS
Descriptions of the 54 or more species in this subfamily are not included here, be- cause many require redescription and adequately preserved material is unavailable. To obviate the problem of deciding on the author's intent in relegating subspecific or in- frasubspecific rank to a taxon (ICZN, Art. 45), we have blanketly endorsed all known nominal taxa, and accordingly assigned them appropriate rank. Our reasons for placing a nominal species or genus in synonymy are given in the remarks section under the respec- tive taxon. For each species, following citation of the author and date of publication, we cite type locality and host-coral. A list of species incertae sedis follows the systematics sec- tion.
Family Balanidae, Leach, 1817
Subfamily Pyrgomatinae Gray, 1825
Balanidae Leach, 1817: 68, in part; Darwin, 1854a: 33, in part.
Pyrgomatidae Gray, 1825: 102, in part; Reichenbach, 1828: 89, in part.
Bifora Latreille, 1825: 234, in part.
Pyrgomacea Menke, 1830: 92, in part; Philippi, 1853: 424, in part.
Sessilia: Philippi, 1836: 247, in part.
Tetrameridae Gruvel, 1903: 159, in part; Alessandri. 1922: 226, in part.
Creusiinae Baluk and Radwahski, 1967c: 468.
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Defjfiition.—Shell of four parietal plates with radii and alae, or totally concrescent, with or without carinal "pseudoalae" discernible in sheath; walls solid or tubiferous, the tubes occurring in one or more rows either between the sheath and internal ribs or be- tween external ribs of wall; scutum and tergum either separate, cemented, or calcified to- gether; basis membranous or calcareous, when calcareous cup-shaped and shallow or cylindrical and deep; labrum with deeply incised notch; intromittant organ with basi-dor- sal point. Obligatory symbionts or parasites primarily of scleractinian corals. (One species occurs on a hydrocoral, another on a sponge.) Type genus: Pyrgoma Leach, 1817.
Key to Genera of Pyrgomatinae
1. Basis membranous (1 sp.) Pyrgopsella
1 . Basis calcareous 2
2. Shell concrescent 3
2. Shell separable into 4 plates 7
3. Scutum at least twice as long as high 4
3. Scutum as long as high 5
4. Tergal spur well developed (1 sp.) Pyrgoma
4. Tergal spur rudimentary 6
5. Opercular plates balanoid, separable; tergum
triangular (4 spp.) Boscia
5. Opercular plates modified, fused together; tergum
quadrate (6 spp.) Nobia
6. Shell irregular in outline; aperture minute (1 sp.) Hoekia n. gen.
6. Shell regular in outline; aperture large (4 spp.) Savignium
1 . Opercular valves fused (3 spp.) Creusia
7. Opercular valves not fused 8
8. Opercular valves highly modified (1 sp.) Hiroa n. gen.
8. Opercular valves balanoid 9
9. Scutum with basal margin entire, depressor muscle pit present, but no rostral tooth; tergum with broad pad in area normally
occupied by depressor muscle crests (16 spp.) Ceratoconcha
9. Scutum with basal margin notched near basi-tergal angle, commonly with depressor muscle pit, and a rostral tooth; tergum without broad pad (17 spp.) Cantellius n. gen.
Cantellius n. gen.
Definition— V^aW of four plates, conical to flat; compartments separated by well de- fined radii; scutum varies from high triangular to transversely elongated, and bearing prominent adductor ridge and lateral depressor muscle depression; scutum commonly with rostral tooth and notch in basal margin near basitergal angle; spur of tergum essen- tially confluent with scutal margin, and about Vi width of basal margin; crests for tergal depressor muscles feebly developed or wanting.
Type species.— Cantellius transversalis (Nilsson-Cantell), 1938; Recent, Andaman Isl- ands.
Etymology.— ^Simtd in honor of Carl August Nilsson-Cantell.
Species assigned to genus:
Cantellius acutum (Hiro), 1938; 398 (syn.: Creusia spinulosa var. 6 subvar. 2 Darwin, 1854: 379); Palao Is- lands, Caroline Islands; on Acropora formosa.
Cantellius arcuatum (Hiro), 1938: 395; Palao Islands, Caroline Islands; on Porites capricornis.
Cantellius hreviter^um (Hiro), 1938: 397; Palao Islands, Caroline Islands; on Acropora sp.
Cantellius et4spinulosum {Broch). 1931: 118 (syn.: Creusia spinulosa vslt. 1 Darwin, 1854: 377); Amboina, Molucca Islands; on Herpetolitha sp.
Cantellius ^regarea (Sowerby), 1823 [no pagination] (syn.: Creuisa spinulosa var. 3 Darwin, 1854: 378; Creusia spinulosa pseudoseptima Kolosvary, 1948: 362; Creuisa spinulosa paeudoseptima [sic]: Kolosvary, 1951 lb: 292); near Kei Islands (5°3rS., 132°47'E.); on Acropora cvtherea. type host here designated.
Cantellius iwavama (Hiro), 1938, p. 393; Palao Islands, Caroline Islands; on Porites iwayamaensis.
Cantellius madreporae {Bormdaile). 1903: 443 (syn.: Pvrgoma madrepoarae [sic]: Nilsson-Cantell, 1938: 65); Hulule, Male Atoll, Maldive Islands; on Madrepora sp.
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Figure 7. Opercular plates of Cantellius. a-c, C. sextus. after Hiro. 1938; d, e, C. arciiatus. after Hiro. 1938; f. C. madreporarae, after Borradaile, 1903; g-i, C. euspinulosum. after Hiro, 1938; j-m, C. iransversalis. after Nil- sson-Cantell, 1938; n-i, C. iwavama, after Hiro, 1938; q, r, C. breviiergum. after Hiro. 1938; s, t. C. iredecimus. after Kolosvary, 1947; u-x, C. acutum. after Hiro, 1938.
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CanlelUus octavus Ross and Newman, n. sp. (syn.: Creusia spinulosa var. 8 Darwin, 1854a: 380); type local- ity, distribution and host coral not known.
Cantellius pallidus (Broch), 1931: 1 18; Banda Sea (5°32'S., 132°37'E.); on Pocillopora damkornis. type host here designated. r
Figure 8. Opercular plates of CanlelUus. a-d, C. secundus. after Hiro, 1938; e, C. septiimis. after Darwin, 1854; f-h, C sumhawae, after Hoek, 1913; i, j, C. gregarea, after Nilsson-Cantell, 1938; k-m, C. sepiimus, after Hiro, 1938; n, C. quinius, after Darwin, 1854; o-r, C pallidus, after Hiro, 1935.
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Caiuelliiis quinius Ross and Newman, n. sp. (syn.: Creusia spinulosa var. 5 Darwin, 1854a: 379); type local- ity, distribution and host coral not known.
Canicllius pseudopullidum (Kolosvarv), 1948: 362: Pacific area: on Pavona varians.
Canicllius secuncjus (Broch), 1931: 118 (syn.: Creusia spinulosa var. 2 Darwin, 1854: 378); offNaira, Banda Islands; on Pavonia sp.
Canicllius sepii'mus (Hiro), 1938: 395 (syn.: Creusia spinulosa var. 7 Darwin, 1854: 380; Creusia spinulosa duodecima Koiosvary and Wagner, 1941: 9); Palao Islands, Caroline Islands; Monlipora sp. cf. M. cacutus.
Canicllius sextus (Hiro). 1938 (syn.: Creusia spinulosa var. 6 suhvar. 3 Darwin. 1854: 379); Palao Islands, Caroline Islands; on Pachvseris rugosa.
Cantellius sumbawae (Hoek), 1913: 265; east of Dangar Besar, Saleh Bay; on Heieropsammia sp.
Caniellius transversalis (Nilsson-Canteli), 1938: 61 (syn.: Creusia spinulosa var. 6 subvar. 1 Darwin. 1854: 379); North Bay, Port Blair, Andaman Islands; on Madrepora sp.
Caniellius iredecimus (Koiosvary). 1947: 426; Island of Singapore; on Tridacophyllia lactiua.
Remarks —Cantellius is proposed for those Indo-Pacific creusoids with unfused oper- cular valves of which the scutum commonly possesses a notch in the basal margin near the basi-tergal angle, a rostral tooth, an adductor ridge, and a lateral depressor muscle pit. The tergum has either feebly developed crests for the depressor muscles, or no crests.
In critically comparing the illustrations and brief description of Creusia spinulosa duodecima Koiosvary (1941: 9) with that of Cantellius septima. the authors find no differences that warrant continued recognition of duodecima. We also find, for the same reasons, that C. spinulosa pseudoseptima is synonymous with C gregarea.
Hiroa n. gen.
Definition— VsldW of four plates, small, flat or low conical; parietal tubes present; sheath occupying whole inner wall; basis cylindrical and deep; triangular scutum high and elongated transversely; adductor ridge projecting below basal margin of valve; ter- gum narrow, with spur about Vi or less height of valve, lacking crests for depressor mus- cles; overall height of tergum greater than that of scutum and about equal in bulk to scutum.
Type species.— Hiroa stubbingsi, new species.
Etvmology.—Na.med in honor of Dr. Fijio Hiro ( = Huzio Utinomi), in appreciation of his numerous studies on the Pyrgomatinae.
Remarks.— Hiroa bridges the gap between Cantellius and the morphologically ad- vanced Indo-Pacific creusoids and pyrgomids. In having a shell with four distinct plates, it is readily separable from Nobia and Pvrgoma. The bizarre development of the opercular plates, which are separate, distinguishes it from Cantellius on one hand, and from Creusia on the other.
Hiroa stubblngsi n. sp.
Diagnosis.— ^QCSi\i?,Q there is but a single known species, the diagnosis is the same as that for the genus.
Material. -^umtrous specimens in Stvlophora sp., type host; OUan Island, Truk Islands, 7°14'N, 151°38'E, type locality; CARMARSEL Exped. sample CRS 811: 25 February 1967; coral blasted from ba.se of seaward reef front at 8 m; c" dating indicates age of less than 500 BP.
/)e.9fr//>//o«.— Specimens were entombed in coral so that the external surfaces of the wall could not be observed; wall of four plates, flat or low conic; outline ovate; rostrocari- nal diameter less than 5 mm, lateral diameter less than 3 mm; parietes non-tubiferous and thickened marginally, thinning toward aperture; sutural surfaces of radii strongly denticulate; sheath extending to basal margin of wall with basal edge depending freely.
Basis deep (greater than 26 mm); cylindrical; strongly ribbed internally; non-tubi- ferous; gradually expanding from point of initial growth.
Scutum high and transversely elongated (1.7 mm high x 1.6 mm wide); exterior sur- face sculptured with irregular, high, growth ridges; tergal margin about Vi length of basal; occludent margin coarsely toothed; internal surface smooth; slight indication of adductor muscle depression; adductor plate extends well below^ basal margin of valve proper; ros- tral angle of adductor plate slightly produced.
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Figure 9. Opercular plates of Hiroa stubbingsi n. gen., n. sp.
Tergum T-shaped or narrowly triangular (2.3 mm high x 1.6 mm wide); external sur- face ornamented with irregular low growth ridges; external longitudinal furrow deep, steep-walled and open throughout its length; internal surface smooth, lacking crests for depressor muscles, deep depression present in area bordering basi-carinal angle.
Disposition of types— Tho. holotype and two paratypes are deposited in the collections of the National Museum of Natural History. The remaining paratypes are housed in the collections of Scripps Institution of Oceanography.
Etymology— ^dimtd in honor of H. G. Stubbings, long-time student of the Cirri- pedia, on the occasion of his retirement.
Genus Creusia Leach
Creusia Leach, 1817: 68. Genus without originally included nominal species; first species assigned to genus: Creusia spinulosa Leach, 1818, Recent, type locality unknown, ipso facto type species by subsequent monotypy (Leach, 1818: 171).
Cerusia (eTTOT for Creusia Leach, 1817): Ranzani, 1818: 92; Ranzani. 1820: 56.
Creusa (error for Creusia Leach, 1817): Catlow, 1843: 39.
Definit ion. —SheW flat, ribbed, compartments separated by narrow radii; parietal tubes absent in small species, rarely present in larger ones; scutum and tergum calcified together without visible indication of line of juncture; adductor "plate" commonly ex- tending below basal margin of valve; where plate extends below margin it is produced as basi-rostral tooth; no distinct lateral depressor muscle depression on scutum; tergal por- tion of valve somewhat quadrate, occupying Vi or more of total area; basis oval, or nearly circular in outline and commonly deep.
Species assigned to genus:
Creusia decima Ross and Newman, n. sp. (syn.: Creusia spinulosa var. 10 Darwin, 1854: 381); type locality, distribution, and host coral not known.
Creusia inJicum (Annanddle), 1924: 64 (syn.: Creusia spinulosa var. 11 Darwin, 1854: 381: Pyrgoma indicum phase merulinae Annandale, 1924: 65; Pyrgoma indicum phase svmphvlliae Annandale, 1924: 65; Creusia spin- ulosa angustiradiaia Broch, 1931: 118; Creusia spinulosa angustiterga [sic]: Nilsson-Cantell, 1938: 63); Padaw Bay, King-Fsland, Mergui Archipelago; on Favia valenciennesii.
Creusia spinulosa Leach, 1818: 171 (syn.: Creusia spinulosa var. 9 Darwin, 1854: 380); type locality, distri- bution, and host coral not known.
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Figure 10. Creusia. a, b, shell and oper- cular plate of C. indicum\ c, opercular plate of C. spinulosa: opercular plate of C decima: all figures after Darwin, 1854.
Remarks— J\vQ original definition of Creusia follows: "Testa quadripartita; oper- culum valvis unipartitis" (Leach, 1817: 68). This was later given by Leach (1818: 171) as: "Shell quadripartite; parts equal. Valves of the operculum unipartite. Base in- fundibuliformis." In reference to Leach's statement that the opercular valves are fused. Gray (1825: 103) stated, in his discussion of C. spinulosa, "Dr. Leach describes the valves of the operculum as soldered two and two, but they are not so in the Museum specimens." Probably the opercular valves of the specimens in question, which are not necessarily a species of Creusia {sensu stricto), are only cemented together, rather than calcified to- gether, and this would account for the discrepancy between the two descriptions.
Of the 13 numbered varieties and sub-varieties of C. spinulosa described by Darwin (1854a), three have not been redescribed nor assigned formal names. For "variety 5" we propose the name Cantellius quintus: for "C spinulosa var. 8," the name Cantellius oc- tavus; for "C. spinulosa var. 10," the name Creusia decima.
Nilsson-Cantell (1938: 63) considered Annandale's phase merulinae and phase sym- phylliae to be synonymous with Creusia spinulosa angustiradiata. This taxon is a junior subjective synonym of C. indica, as noted by Utinomi (1962: 227), who also followed Nil- sson-Cantell's suggestion in synonymizing Annandale's several "phases."
Genus Nobia Sowerby
Nobia Sowerby (ex Leach), 1839: 71. Type species: N. [obia] grandis Sowerby, Recent, Island of Singapore (type locality here designated), by monotypy.
Definition. —ShQ\\ flat or conical, ribbed or smooth, composed of one piece lacking all evidence of radii and alae; shell perched on basis; sheath applied directly to wall, extend- ing to, or nearly to basis; opercular valves nearly of equal size and fused, with line of fu- sion invisible, or visible either externally, internally, or both; scutal portion of valve quadrate to subquadrate in outline; basis deep, cylindrical, and either exserted or flush with corallum.
Species assigned to genus:
Nobia conjugcilum (Darwin). 1854: 364; Red Sea; on Cvphastraea chalcidkum.
Nobia grandis Sowerby, 1839: 71; Singapore; on Galaxea musicalis.
Nobia halomitrae (Kolosvary), 1948: 363; type locality and distribution unknown; on Halomitra sp.
Nobia kuri(\\oQk). 1913; 259; near Kei Islands (5°28.4'S., 132°0.2'E.,); on Caryophvllia sp.
Nobia orbicellae (Hiro), 1934: 367; Tanabe Bay, Japan; on Goniopora sp.
Nobia projectum (Nilsson-Cantell), 1938: 70; Persian Gulf; on Carvophvlh'a sp.
Remarks.—SoweThy^ (1839: 71) original definition of Nobia is: "This genus resem- bles Pyrgoma, Auct. consisting of a conical paries supported upon a funnel-shaped cavity in the madrepore, but diff'ers in its operculum, which consists of two valves; whereas that of Pyrgoma has four."
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Figure 11. Nobia grandis on Euphyllia fimhriata (Spengler); Warrior Reef, Torres Straits, Australia; Museum Comparative Zoology coral 5685.
Genus Pyrgoma Leach
Pyrgoma Leach (ex Savigny MS), 1817: Genus without originally included nominal species; first species as- signed to genus: Pyrgoma cancellata Leach, 1818, Recent, Indo-Pacific, ipso facto type species by subsequent monotypy (Leach, 1818, 171; and by subsequent designation of Brooks and Ross, 1960: 354).
Pvrgone (Qxxox ior Pyrgoma hQ&dn, 1817): Ferrusac, 1822: 144.
Pyrgona (quov ior Pyrgoma 'L&&c\\, 1817): Catlow, 1843: 39.
Pvrgomum (error for Pyrgoma Leach, 1817): Darwin, 1854: 364 (footnote).
Pyrogoma (error for Pyrgoma Leach, 1817): Kolosvary and Wagner, 1941: 12; Kolosvary, 1943: 95.
Pytgoma (error for Pyrgoma Leach, 1817): Johnson, 1963: 95.
Definition. —Shell large, flat to sub-conical, plates totally fused; short adpressed sheath covers about 1/5 height of inner wall; parietal tubes present; triangular scutum high and elongated transversely; adductor ridge projecting below basal margin of valve; tergum extremely narrow, with spur % to Va height of valve; lacking crests for depressor muscles; overall height of tergum greater than that of scutum, but about '/> bulk of scu- tum.
Species assigned to genus:
Pyrgoma cancellata Leach, 1818: 171 (syn.: Pyrgoma lobata Gray, 1825: 102; Pyrgoma cancellaliim var.Japo- nica Wehner, 1897: 255); Sirahama, Honshu Island, Japan, type locality here designated; on Turhinaria contorta.
Remarks.— Leach's (1817: 68) original definition of Pyrgoma is: "Testa unipartita; operculum valvis bipartitis." In subsequent publications Leach (1818, 1825) neither en- larged nor amplified this description.
Pyrgoma cancellata is the only species assigned to this genus. The unusual devel- opment of the opercular valves, especially the tergum, and the concrescent shell, serve to distinguish it from those species previously referred to Pyrgoma.
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Figure 12. Opercular plates of Nobia. a-c, N. ^randis. after Darwin, 1854; d, e. .V. conjugaium. after Darwin. 1854; f, g, N. kuri, after Hoek. 1913; h. ,V. halomiirae. after Kolosvary. 1948; i. j. ,V. projecium. after Nilsson- Cantell, 1938; k, 1, N. orbkellae, after Hiro, 1935.
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Figure 13. Pyrgoma cancellata Leach on Dendrophvllia micranthus grandis Crossland; Great Barrier Reef, Aus- tralia; Zoologisk Museum, Copenhagen.
Figure 14. Opercular plates of Pyrgoma cancellata, after Hiro, 1935.
Genus Savignium Leach
Savignium Leach, 1825 (not Sowerby, 1823, nomen nudum): 210. Genus without originally included nomi- nal species; first species assigned to genus: D. [aracia] linnaei Gray, 1825 [ = Savignium crenaium Sowerby. 1823], Recent, Island of Singapore (type locality here designated), ipso facto type species by subsequent monotypy (Gray, 1825: 102).
Daracia Gray, 1825: 102. Type species: D. [aracia] linnaei [ = Savignium linnaei = Savignium crenatum So- werby, 1823], Recent, Philippine Archipelago, by monotypy.
Z)orada (error for Z)arac/a Gray, 1825): Weltner, 1897: 278.
Definition —Shell totally fused, flat, oval in outline; lower margin of sheath free, ex- tending nearly to basal edge of wall; opercular valves separate, cemented, or fused to-
159
Figure 15. 1868.
Savignium crenatum on Merulina ampliata Ellis and Solander; Singapore; American Museum coral
gether; scutum transversely elongated, its overall length exceeding that of tergum; tergum variable, commonly lacking definitive spur and lacking crests for depressor muscles; scu- tum comprising bulk of operculum; basis commonly deep and cylindrical. Species assigned to genus:
Savignium crenatum Sowerby, 1823, no pagination (syn.: Pyrgoma crenatum phase tridacophvlliae Annan- dale. 1924: 66; Pyrgoma crenatiformis Kolosvary, 1951: 287); Singapore, type locality here designated; on Tri- dacophvllia lactuca.
Savignium dcnialum Darwin. 1854: 369; Red Sea; on Meandrina spongiosa.
Savignium elongatum Hiro. 1931; 154; Sirahama. Honshu Island. Japan; on Madrepora sp.
Savignium milleporae Darwin. 1854: 367 (syn.: Pyrgoma millepora [sic]: Nilsson-Cantell. 1938: 65; Pyrgoma milleporae forma typica Kolosvary, 1950: 292; Pyrgoma milleporae CoTma snelliusi Kolosvary, 1950: 292); Min- doro Island. Philippine Archipelago; on Millepora complanata.
Remarks— Aiter Leach (1817, 1818) published his first two studies on the Cirripedia he subdivided Pyrgoma and proposed the genera Savignium, Megatrema, and Adna. Al- though he did not publish these names until 1825, he did leave labeled specimens in the British Museum (Natural History) collections (see Sowerby, 1823; Gray, 1825: 107). So- werby (1823) found ". . . upon examining the collection of Cirripedes, in the British Mu- seum, as it now remains arranged by Leach himself, that since the publication of the 'Supplement to the Encyclopedia Britannica,' where the characters of the genus [Pyr- goma] first appear in print, he [Leach] had divided into four; upon what grounds we must acknowledge ourselves entirely ignorant, except it be from some diff"erences in the form of the shell, and the valves of the operculum . . . We do not consider . . . these four genera . . . sufficiently distinct to constitute several genera . . . wherefore we still include all above enumerated [Megatrema, Savignium, and Adna] under the denomination of Pyrgoma^
Sowerby is not considered the author of Megatrema, Savignium, or Adna, although his publication has priority, because, "A name first published as a synonym is not thereby
160
Figure 16. Savignium milleporae on Mil- lepora sp.; Heron Island, Great Barrier Reef, Australia.
made available unless prior to 1961 it has been treated as an available name with its origi- nal date and authorship, and either adopted as the name of a taxon or used as a senior homonym" (Article 1 1 (d), ICZN). Sowerby's use of the specific names, Savignium crena- tum and Adna anglica, suggested by Leach, on the other hand, entitles him to the author- ship of these.
Leach's second synopsis of the Cirripedia, published in July of 1825, contained brief descriptions of Savignium, Megatrema, and Adna. At the same time Leach was working on his manuscript. Gray (1825) was also preparing a synopsis of the Cirripedia, which was pubhshed in the August issue of the Annals of Philosophv. In his synopsis. Gray (1825: 102) described the genus Daracia as follows: ""Daracia, Gray, Savignium, Leach, without character. Valves of the body of the shell, four, soldered together." This description com- pares favorably with Leach's abbreviated description of Savignium: "Testa indivisa: basis immersa, valvae indivisae" (1825: 210). The only species mentioned by Gray in con- nection with the definition of Daracia is linnaei, which is not described. In the discussion of Pyrgoma, Sowerby (1823) made reference to Savignium crenatum, which he attributed to the authorship of Leach. That Gray referred to the same specimens as did Sowerby, who figured them, seems probable at this time, and Gray more than likely based his con- cept of D. linnaei on these specimens. Therefore, we believe that Gray's D. linnaei is ac- tually a junior objective synonym of Savignium crenatum. It should also be noted that Gray, proposed Daracia as a replacement name for Savignium (see Gray 1825: 102, foot- note).
Based on the general aspects of barnacles overgrown by a milleporine, Darwin (1854: 366) suspected Chenu's (1843) Creusia madreporarum to be synonymous with his Pyr- goma milleporae. Chenu, questionably, ascribed this taxon to the authorship of Leach, and his illustration speaks favorably of its being the same as Darwin's taxon. So far as we have been able to determine, the only pyrgomatid reported from a milleporine is P. mille- porae. In the interests of stability, although recognizing that C madreporarum has prior- ity, Darwin's name is used here.
Two forms of Pyrgoma milleporae were designated by Kolosvary (1951: 292), typica ( = P. milleporae milleporae) and snelliusi. These are not recognized here because the mor- phological variations recorded fall within the limits of variation assumed to correlate with different infrageneric milleporine associations.
In the coral collections of the American Museum there are two large specimens of Merulina ampliata (cat. no. 1868 and 3214) from the Island of Singapore infested with pyrgomatids. Our study of these indicated that they are conspecific with Pyrgoma crena- tum. In 1951 Kolosvary described P. crenatiformis from the coral Merulina ampliata, col-
161
ra
Figure 17. Opercular plates of Savignium. a-d, S. crenatum. after Hiro, 1935; e-g, 5'. milleporae. after Darwin, 1854; h-k, S. denialum. after Hiro. 1935 and 1938; 1-n. S. elonganinu after Hiro. 1938.
lected in the vicinity of the Island of Singapore. Comparison of our specimens with Kolosvary's illustrations and brief description does not reveal differences that enable one to separate these two species.
Hoekia n. gen.
Definit ion. —SheW totally concrescent, irregularly lobate in outline, and exhibiting no definitive peripheral shape; region surrounding minute ovate orifice elevated above exter- nally flat or undulatory surface of shell; sheath short, adpressed, basal margin not de- pending freely; irregularly scattered wall tubes occur at varying distances from shell
162
Figure 18. Hoekia monticulariae. Left, on Hydnophora exesa (Pallas); Mortensen Java-South Africa Expedition 1929-30; Station 44, Flat Island, Mauritius; Zoologisk Museum, Copenhagen. Right, internal view of shell from Hydnophora exesa; Singapore; American Museum coral 1883.
margin; operculum minute; scutum and tergum fused without evidence of suture, form- ing elongate valve with broad occludent ledge; tergal end of valve lacking spur.
Etymology —This taxon honors the late Dutch cirripedologist Paulus Peronius Cato Hoek(1851-1914).
Type species.— Pyrgoma monticulariae Gray, 1831, Recent, Island of Singapore.
Species assigned to genus:
Hoekia monticulariae (Gray), 1831: 6; Singapore; on Hydnophora exesa.
Remarks.— ThQ gross differences between the shell and opercular valves of mon- ticulariae and those of other Pyrgomatinae are of sufficient magnitude to warrant its sepa- ration as a distinct genus (see Ross and Newman, 1969).
Although Baluk and Radwahski (1967b: 487) resurrected the name Daracia to in- clude Pyrgoma monticulariae and P. elongatum, it is readily apparent that not only was Daracia proposed as a replacement name for Savignium (see Gray, 1825: 102, footnote), but also the type species D. linnaei appears to be a junior objective synonym of 5". crena- tum. Consequently, we feel justified in proposing a new taxon.
Hoekia is allied morphologically to Savignium in that the fused opercular valves show some affinity to those of S. crenatum, S. dentatum, and less so to S. milleporae, as pointed out by Darwin (1854a: 374). But, in these species the valves are separate or only cemented together.
Figure 19. Opercular plate of Hoekia monticulariae: top, after Darwin, 1854; bottom, after Hiro, 1935.
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Figure 20. Shell and opercular plates of Pvr^opseUa annandalei. redrawn after Gruvel, 1907.
Aside from the fact that H. monticulariae is the only known wholly parasitic balanid, the trophi of this species depart radically from those of other pyrgomatines (Ross and Newman. 1969: 255). Apparently, critical study of the mouth field should provide addi- tional and independent criteria for recognition of pyrgomatine generic groups. Our pre- liminary studies of species having morphologically primitive shells indicate that the trophi of these depart little from that of many primitive balanids (see Broch, 1924, fig. 10).
Genus Pyrgopsella Zullo
Pyrgopsis Gruvel, 1907: 8. Type species: Pyrgopsis annandalei Gruvel, Recent, Andaman Islands, by mono- typy.
Pyrgopsella Zullo, 1967: 109 (substitute name for Pyrgopsis Gruvel, 1907, not Rochebrune, 1884).
Definition.— V^dW subconical, rostro-carinally elongate, smooth, composed of numer- ous calcareous rods contained in a chitinous envelope continuous with basis; basis elon- gate and membranous; opercular plates separate, well calcified, scutum transversely elong- ated; tergum triangular with short irregular spur; living in sponges.
Species assigned to genus: Pyrgopsella annandalei (Gr\i\Q\), 1907: 8: Andaman Islands; host unknown.
Remarks— T\\Q remarkable feature in Pyrgopsella is the membranous basis that Gru- vel (1907: 9) thought served as a peduncle. Rosell (pers. comm.) recently discovered a new species of Pyrgopsella living in a sponge in the Philippines, and from this it is clear that the function of the elongate membranous basis is comparable to that of the elongate calcareous basis of the other pyrgomatines, and that being membranous is simply a sec- ondary adaptation to living in sponges as opposed to corals.
Utinomi (1943: 16) studied the post larval settlement stages in Creusia indicum, and found the basis to be initially cup-like and wholly membranous. It is evident that calcifi- cation of the basis is delayed, at least in C. indicum, and hence it is not difficult to envis- age that in Pyrgopsella ontogenetic suppression of calcium deposition would result in a membranous basis.
The general shape of the shell and the opercular plates of Pyrgopsella are similar to those found in Savignium dentatum. From the morphology of the hard parts it is apparent that Pyrgopsella was derived from Savignium.
Genus Boscia Ferussac
Boscia Ferussac. 1822: 145. Type species: Balanus madreporarum Bosc, 1812 [ = Boscia madreporamm (Bosc)], Recent, Caribbean-western Atlantic, by monotypy.
Megatrema Leach, 1825 (not Sowerby, 1823, nomen nudum): 210. Genus without originally included nomi- nal species; first species assigned to genus: M. [egalrema] slokesii Gray, 1825 [ = Boscia madreporarum (Bosc), 1812], Recent, Caribbean-western Atlantic: ipso facto type species by subsequent monotypy (Gray, 1825: 102), and subsequent designation of Philippi ( 1853: 424).
Adna Leach, 1825 (not Sowerby, 1823, nomen nudum): 210. Genus without originally included nominal spe-
164
'■*?-l*^,* .lit
r^^
■iMIiiiMi
Figure 21. Boscia madreporarum on Agahcia agahcites (Linnaeus); Dry Rocks, off Key West, Florida.
cies; first species assigned to genus: M. [egatrema] (A. [dna]) anglica Gray, 1825 \ = Boscia cmglicum Sowerby, 1823], Recent, coast of Devonshire, England; ipso facto type species by subsequent designation of Philippi ( 1853: 424).
Pyrgominia Baluk and Radwahski, 1967b: 691. Type species: Pvrgominia seguenzai Baiuk and Radwanski, 1967 [ = Boscia seguenzai Baluk and Radwanski], by original designation. Pliocene, Island of Crete, Greece.
Definition.— SheW conical in juveniles and commonly flat or low conical in later stages; shell plates totally fused externally; pseudo-alae may be present; sheath adpressed and covering % to entire inner wall; opercular valves typically balanoid; terga lacking depressor muscle crests; basis cup-shaped or sub-cylindrical, exserted or flush with coral- lum.
Species assigned to genus:
Boscia angliciim Sowerby, 1823 [no pagination] (syn.: Pvrgoma sulcatum Philippi, 1836, pi. 12, fig. 24; Pvr- goma undaium Michelotti, 1839: 140-141); coast of Devonshire, England; on Carvophyllia smilhii.
Boscia madreporarum {Bo^c), 1812: 66 (.syn.: Creusiaboscii DeBlainville, 1824: 378; Pvrgoma stokesii Gray, 1825: 103; Creusia decorata Chenu, 1843 [no pagination]; Pvrgoma stockesi [sic]: Kruger, 1940: 382); "Ame- rique" [ = Caribbean western-Atlantic]; on Agaricia agaricites.
Boscia oulastreae (Utinomi), 1962: 83; Nomosaki, Kyushu Island, Japan; on Oulastrea crispata.
Boscia seguenzai (Baluk and Radwahski), 1967b: 691; Gournes, Island of Crete, Greece; Pliocene.
Remarks— FeTuss'dc''s (1822: 14) original description of Boscia follows: "Test univalve en cones tres-surbaisse, a parois tubuleuses; articule avec la base. Celle-ci, plus grande, en- forme de godet ou de cupule. "
in the year following the publication o{ Boscia, Sowerby (1823) published two manu- script names of Leach: Megatrema and Adna. When Sowerby described Megatrema he failed to mention any nominal species. Subsequently, stokesii was assigned to the genus (Gray, 1825: 103). However, it appears that Megatrema stokesii is a junior subjective syn-
165
Figure 22. Boscia madreporarum ( = Pvrgoma stokesii). Top, slab with several shells and opercular valves mounted and identified by Darwin: bottom right, external view of shell shown at top center of slab; bottom left, internal view of shell shown at top left of slab. British Museum (Nat. Hist.) 1962. 12.7.1.
onym of Boscia madreporarum, because there are no differentiating morphological fea- tures, and because it occurs on the same host coral, Agaricia agaricites (Linnaeus), in the same geographical region.
Adna was described by Sowerby (1823) as a subjective synonym of Pvrgoma. How- ever, Sowerby is regarded as the author only of the specific name anglica (see Article 1 1(d), ICZN). Leach, who originally proposed Adna, did not publish the name until 1825. At that time no nominal species was assigned to the genus. Gray (1825: 103) included only one species, Adna anglica.
The manner is which Gray (1825: 103) cited the taxon Adna suggests that it was to be recognized as a subgenus of Megatrema. He did not state why this, rather than a generic assignment was made, nor did Darwin (1854: 360) who also cited Adna as a subgenus.
Leach's original definition of Megatrema is "Testa indivisa: basis immersa, valvae Balani," while that of Adna is: "Testa indivisa: basis exserta, valvae Balani" (1825: 210). The only difference between the two, as proposed by Leach, is in the basis, which in Adna is not flush with the surface of the corallum.
Of the pyrgomatids known to Darwin (1854a: 355), only Pyrgoma stokesii { = Boscia madreporarum) and P. anglicum ( =5. anglicum), ". . . have some claims to be generically separated from the other species of Pyrgoma . . ." This opinion was based on the sim- ilarity of the operculum, and the conical shells which internally exhibit carinal pseu- doalae. The authors have adopted Darwin's suggestion and maintain these two species, in addition to Boscia oulastreae and B. seguenzai in a distinct genus.
What have been interpreted as carinal sutures are a pair of fines where the arthrodial
166
Figure 23. Opercular plates of Boscia. a, b, B. anglicum, after Darwin, 1854; c-f, B. oulastreae, after Utinomi, 1962; g, h, B. madreporarum.
membranes of the scuta and terga attach to the sheath. As the operculum is carried ba- sally with growth of the sheath, the Hnes remain marking the points of earher attachment. These Hnes could represent vestiges of the suture, but they appear only in the sheath and not the wall. When the shell is ground transversely, the area beneath the lines has a folded appearance; the overlapping portion being termed a pseudoala.
Genus Ceratoconcha Kramberger-Gorjanovic
Ceratoconcha Kramberger-Gorjanovic, 1889: 50. Type species: Ceratoconcha costata Kramberger-Gorjano- vic [ = Creusia krambergeri nom. nov. = Ceratoconcha krambergi (Baluk and Radwanski), 1967: 145], Miocene, Yugoslavia, by monotypy.
Paracreusia Abel, 1927: 101. Type species: Paracreusia trolli Abel [ = Ceratoconcha trolli (Abel)], Miocene, Italy, by monotypy.
Andromacheia Kolosvary, 1949: 4. Type species: Andromacheia noszkvi Kolosvary [ = Ceratoconcha noszkvi (Kolosvary)], Upper Miocene, southern Hungary, by monotypy.
Withersia Baluk and Radwanski, 1967c: 485. Type species: Creusia barbadensis Withers, Pleistocene, Bar- bados by original designation.
Definition. -~?i\\Q\\ of four compartments separated by radii and alae, the latter trend- ing toward reduction in size; shell ribbed, ranging from conical to nearly flat; sheath ap- proximately Vi height of wall, with basal margin depending freely; well developed ribs may occur on inner surface of shell and extend from base to sheath; opercular valves typi- cally balanoid; rostral tooth of scutum either inconspicuous or wanting; well developed lateral depressor muscle pit present; tergum commonly bears a prominent ridge or plate on carinal segment, rather than depressor muscle crests; basis commonly deep and cy- lindrical.
Species assigned to genus:
^Ceratoconcha barbadensis (Withers), 1926: 2 (syn.: Creusia barndensis [sic]: Nilsson-Cantell, 1938: 63); Barbados, West Indies; Pleistocene.
^Ceratoconcha costata (Sequenza), 1876, p. 316 (syn: Creusia costata elargata (Sequenza), 1876: 317; Creusia moravica Prochazka, 1893: 20; Creusia spinulosa forma, praespinulosa Kolosvary, 1949: 1, fig. 5 only; Creusia spinulosa forma kojumdgievae Kolosvary, 1962: 86); Messina, Italy; Pliocene (Astian).
^Ceratoconcha darwiniana {Proishdzkd). 1893: 23; Leibnitz, Australia; Miocene.
\ Ceratoconcha diploconus (Seguenzsi), 1876: 322; Messina, Italy; Pliocene (Astian).
Ceratoconcha domingensis (Des Moulins), 1867: 307; Port-au-Prince, Haiti; on Porites astreoides.
Ceratoconcha floridanum (Pilsbry), 1931: 81; Gulf of Mexici>; on Maeandra sp. cf. M. areolata.
1; Ceratoconcha krambergeri (Baluk and Radwaiiski), 1967a: 145 (see Kramberger-Gorjanovic, 1889: 50); Podsused, Yugoslavia; Miocene.
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Figure 24. Ceratoconcha fioridanum on MvcetophvUia lamarckana Milne-Ed- wards and Haime; Recent, Florida Keys.
^Ceratoconcha miocaenica (?xoc\\dLzk3i), 1893: 22; Wollersdorf, Austria: Miocene.
^Ceratoconcha noszkvi (V^o\o^\iL'[y), 1949: 4; Magyarszek, Hungary; Miocene.
^Ceratoconcha prefioridana (Brooks and Ross), I960: 355 (syn.: Creusia neogenica weisbord, 1972: 60); Florida, U.S.A.; Pliocene; on Manicina mayori.
Ceratoconcha quaria (Kolosvary), 1947: 426 (syn.: Creusia spinulosa var. 4 Darwin, 1854: 378); West Indies; West Indies; on Colpophvllia nutans.
^Ceratoconcha rangi rangi (Des Moulins), 1867: 302 (syn.: Pyrgoma miilticostatum Seguenza. 1873: 319; Creusia fuchsi Prochazka, 1893: 18; Creusia spinulosa forma, caldangiae Kolosvary. 1949: 1; Creusia spinulosa formd praespinulosa Kolosvary, 1949: I, figs. 2-3 only); Bazas, France; Miocene (Aquitanian).
j Ceratoconcha rangi latum (Seguenza). 1876: 321; Rometta, Italy; Miocene (Tortonian).
\ Ceratoconcha sanctacrucensis Baluk and Radwaiiski, 1967c: 468; Korytnica, Poland; Miocene (Torton- ian); on Tarhellastraea reussiana
^Ceratoconcha sturi (?xoc\\azka), 1893: 15; Sudic, Czechoslovakia; Miocene.
^Ceratoconcha trolli (Abd). 1927: 101: Voslau, Austria; Miocene: on Siderastraea crenulata.
Remarks— \n view of the allocation of the coral-inhabiting barnacles to different gen- era, the specific name Ceratoconcha costata, proposed by Kramberger-Gorjanovic (1889: 50), becomes a junior homonym of^ Creusia costatuni (Sequenza, 1876: 316). As a replace- ment for this preoccupied name, Baluk and Radwahski (1967a: 145) proposed Creusia kramhergeri.
The validity of Paracreusia has long been questioned (Withers, 1929: 565: Hiro, 1938: 414; Kriiger, 1940: 452), because no apparent differences allowing separation from Ceratoconcha were noted by Abel (1927, 1928), or subsequent workers. Baluk and Rad- wahski (1967c: 482) suggested merging Paracreusia, a proposal we have adopted here.
Kolosvary (1949: 4) proposed Andromacheia on the basis of one poorly preserved specimen with visible and irregularly developed squamate compartments. The shell sur- face was said to bear three rows of scales. These are probably the result of weathering in- asmuch as the same feature was noted in Ceratoconcha cladangiae (Kolosvary, 1949: 2); therefore they are not considered to be of major taxonomic significance. The poor demar- cation of the parietal plates and poor development of radii and alae, as noted by Kolos- vary, is often encountered in fossil material. Baluk and Radwahski (1967c: 476) questioned "^hQihtx Andromacheia was even a barnacle.
Many fossil Pyrgomatines have been described from specimens lacking morphologi- cally important details (Baluk and Radwariski, 1967c: 482). Many of these are based on unique specimens, and many of them have not been reported or described since their in-
168
Figure 25. Opercular plates of Cerato- concha. a, b, C. quaria, after Darwin, 1854; c-e, C. preflondamim, after Brooks and Ross. 1960.
itial publication. Over half of the species assigned to Ceratoconcha were originally based on incomplete specimens and still are known to us solely on the basis of an abbreviated, incomplete description. Invariably these descriptions omit the morphology of the oper- culum, which is perhaps the most diagnostic feature of this genus. Therefore, the assign- ment of many of the species must remain tentative until well preserved and more complete material becomes available.
Baluk and Radwahski (1967c: 485) proposed the subgenus Withersia for two species, one of which, Creusia barbadensis, is here referred to Ceratoconcha, and the other, C ou- lastreae, to Boscia. The reason for proposing Withersia was that the radial sutures are "in- distinct or even disappearing." In barbadensis sutures are present, but poorly discernible or obscure largely due to secondary calcification, whereas in oulastreae radial sutures are never present in the adult stage.
Incertae Sedis
The following taxa cannot be assigned to any of the genera defined herein: Creusia childreni Gray, 1825; Balanus duploconus Lamarck, 1818; Megatrema semicostata So- werby, 1839; Pyrgoma stellata Chenu, 1843; Pvrgoma spongiarum Chenu, 1843; Pyrgoma corymbosa "Valenciennes" Chenu, 1843; Creusia radiata Chenu, 1843; Creusia multi- striata Chenu, 1843; Creusia madreporarum "Leach?," Chenu, 1843; Creusia striata Chenu, 1843; Pyrgoma undata Michelotti, 1839.
Darwin (1854: 365, footnote) noted that Balanus duploconus Lamarck may be synon- ymous with Nobia grandis Sowerby. Lamarck's (1818: 394) description, "R testae parte suprema univalvi, indivisa, convexa; inferiore turbinata, non clausa; apertura elliptica," may also apply to other species here included in the genera Nobia, Pvrgoma, or Boscia. The uncertainty that surrounds the nature of B. duploconus, which Lamy and Andre (1932) failed to clarify, stems from the lack of a more complete description.
Schluter (1838: 38) considered Lamarck's Balanus duploconus to represent a distinct
169
genus, for which he proposed Duplocona, with D. laevigata Schluter (=Balanus dupl- oconus Lamarck, 1818) as the sole nominal species. Although D. laevigata is accompanied by a reference to Lamarck's work, no description or illustrations are given, the section on barnacles being for the most part a list of names. Pilsbry (1916: 261), without any comment, placed Schluter's taxon in the synonymy of Pvrgoma as then recognized. Because of the dubious nature of Balanus duplocomis, Duplocona cannot be defined.
Both Creusia childreni and Megatrema semicostata are presented without description or locality. Sowerby's illustration of the external surface of A/, semicostata is too small and generalized to be of any taxonomic value. Creusia childreni was not figured.
In his "Illustrations Conchyliologiques" Chenu (1843) figured seven species of Creusia and five species of Pvrgoma. Of these, only Creusia grandis, C decorata, C. mad- reporarum, Pvrgoma cancellatum, and P. crenatum can be identified with any certainty. The lack of text, figure explanations, or locality data, precludes identification of the re- maining seven species.
The illustration of Creusia striata presented by Chenu shows only the internal surface of the shell in situ. Close inspection reveals six fines marking the interior surface of the sheath, indicating that the wall is composed of six plates. Therefore, Chenu's form is ei- ther a species of Balanus or Hexacreusia.
Darwin (1854: 364 footnote) stated that J. E. Gray thought Pvrgoma stellata Chenu was a synonym of P. conjugatum Darwin. However, Darwin commented that, ". . . it may be so; but the figure given of the shell will do equally well or rather better for the Pvrgo- mum [sic] dentatum of this work, and for some varieties of P. crenatum."'' The uncertainty regarding the identity of P. stellata stems from the lack of illustrations of the opercular plates.
ACKNOWLEDGMENTS
It is with great pleasure that we acknowledge the assistance of numerous friends and associates during the more than thirteen years we have devoted to preparing this revision. We are especially indebted to Patricia L. Barker, British Museum (Natural History); Roger Batten, American Museum of Natural History: Harold K. Brooks, University of Florida; William K. Emerson, American Museum of Natural History; Peter Glynn. Smithsonian Tropical Institute of Research; Ivan Goodbody, University of West Indies; the late Thomas Goreau. University of the West Indies; J. P. Harding, British Museum (Natural History); Meredith L. Jones. Smithsonian Institution; Harry Ladd, U. S. Geological Survey; John Moyse, Iloilo University, Philippines; An- drez Radwahski, University of Warsaw; the late William J. Rees, British Museum (Natural History); Jack Rud- loe. Gulf Specimen Corporation; Donald Squires, Smithsonian Institution; Huzio Utinomi, Seto Marine Biological Laboratory; Stephen Wainwright, Duke University; and Victor A. Zullo, California Academy of Sci- ences.
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Department of Paleontology, Natural History Museum, P.O. Box 1390, San Diego, California 92112, and Scripps Institution of Oceanography, La Jolla, California 92037.
O- fvi-J
MUS. CO MP. ZOOL LIBRARY
HARVARD UNlVeRSITYi
BIOLOGY, GEOGRAPHICAL DISTRIBUTION, AND STATUS OF ATTEVA EXQUISITA (LEPIDOPTERA: YPONOMEUTIDAE)
JERRY A. POWELL, JOHN ADAMS COMSTOCK AND CHARLES F. HARBISON
TRANSACTIONS
OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
VOL. 17, NO. 13 14 MAY 1973
BIOLOGY, GEOGRAPHICAL DISTRIBUTION, AND STATUS OF ATTEVA EXQUISITA (LEPIDOPTERA: YPONOMEUTIDAE)
JERRY A. POWELL, JOHN ADAMS COMSTOCK AND CHARLES F. HARBISON
ABSTRACT.— Moths of the genus Altera are colorful insects that are often encountered at flowers during daytime. Taxonomic relationships among the ten described New World species are poorly known. Three spe- cies occur in Nearctic North America: the widespread punciella Cramer, the quite similar exquisita Busck which was formerly known only from northern Mexico, and a dissimilar endemic in Florida, floridana Neumoegen. The geographical distribution and status o{ exquisita in relation io punctella are analyzed. The two are allopatric with a meeting and possible blend zone near the Rio Grande. The northward spread of punctella following the distribution of adventive A ilanthus trees is documented. The biology and behavior of exquisita. based primarily on a recently discovered colony in southeastern California, and the relationship of the distribution of this moth to various Simaroubaceae are examined. After a long premating period, mating takes place at the onset of the light phase of the diel cycle; oviposition occurs at the end of the light phase, on fibrous substrates, probably mainly in the larval webbing in the field; larvae feed gregariously in a tent-like shelter, using flowers and seed o{ Castela emoryi and also foliage of more leafy host plants, reaching maturity in about 50 davs at laboratory temperatures; pupation occurs in a frail cocoon within the larval tent; the pupa remains in place at emergence of the moth. The species is multivoltine. apparently without a diapause period. The egg, larva, and pupa are described.
Members of A tleva are colorful, rather conspicuous moths that are encountered during the daytime at flowers but apparently are essentially crepuscular and nocturnal in behavior. The genus is primarily Pan-Tropical in distribution, consisting of some 50 species, half of which are described from the Indo-Malayan area. About ten New World species have been described, and these are concentrated in the Antillean and circum-Caribbean region. There are three species represented in the Nearctic: the v/idespread punctella (Cramer) ( = aurea Filch)., floridana Neumoegen in Florida and exquisita Busck, previously known only from northern Mexico. Despite the relatively large size of the individuals compared to most so- called Microlepidoptera, and their conspicuousness, no satisfactory taxonomic treatment exists for New World species. Most of the described Neotropical species have been in- adequately sampled to enable firm conclusions on geographical variation and relation- ships.
In 1966 our attention was called to the occurrence ofanAtteva near Coyote Wells, Im- perial County, in the Colorado Desert area of southern California, when larvae were col- lected by R. V. Moran. Records at the California Department of Agriculture, Sacramento, showed that this moth had been discovered in California by R. A. Flock of the University of California, Riverside, who collected larvae "near Seeley," Imperial County in November, 1964. Probably the actual source was the same colony from which our collections were made. Moths reared from the Moran collection were determined asAtteva exquisita Busck (1912), described from Mobano, Coahuila, Mexico. This species has received little notice since its original description, and apparently it was not collected again until recently.
The California population, which is located in an isolated grove of Castela (Hola- cantha) emoryi Gray (Simarubaceae) seven airline miles southeast of Coyote Wells, Impe- rial County, was used as the principal source of material in our biological study. The locality was revisited by Calvert Norland and Powell in June, 1966; by Harbison in December, 1966; and by Powell in October, 1967, and June, 1968, to obtain additional information on the habits of this moth. Our observations, together with data based on scattered collections made in Baja California, Mexico, should prove of value in assessment of comparative biol- ogy when a comprehensive study of relationships in American Atteva is realized. Various aspects of the bionomics of Atteva punctella have been recorded from the eastern United States, and that species recently has been exten.sively studied in Connecticut (Taylor, 1966, 1967). Nothing has been reported previously on the biology of exquisita.
SAN DIEGO SOC. NAT. HIST. TR.ANS. 17( 13): 175-186. 14 MAY 1973
176
Figures 1-10. Adults of /I //eva: \,punctella female. 5 mi. W. Cave City, Ky. VIII-3/4-71 (J. Powell) 1, punctella male, Alexandria, Va. IX-17-70 (J. Powell). 3, exquisita female, 3 mi. E. Galeana. N.L.. Mex. VIII-7/9-63 (Duck- worth & Davis). 4, excjuisiia male, 7 mi. SE. Coyote Weils, Calif. V 1-25-66, r. f. Holacantlui emoryi (J. Powell No. 66F13) 5, exqiiisita female, isla San Francisco, Goifo de California. Mex. IV- 17-62 (Harbison), b.exquisiia female. 21 mi. W La Paz. Baja, Calif. Mex. V 11-9-66 (J. A. Chemsak). 7, ^. punctelltiXexc/uisiia {pufMive blend zone pop- ulation) female and male, 20 mi. S. Sabinas Flidaigo. N.L.. Mex. Vll-7-66 (Buckett & Ciardner). 9. aberrant fe- male same data. 10, exquisita aberrant female, same data as fig. 4.
177
PHENOTYPIC VARIATION
Atteva exquisita differs from A. punctella, a widespread Neotropical species originally described from Surinam, and other similar described species (Walsingham, 1914) by having the yellow transverse bands of the orange forewing paler and relatively unbroken by dark lines. In particular, the submedian band is composed of about 4 to 7 separate pale spots in punctella and 2 to 4 in exquisita; the postmedian band is a granulated-appearing patch of 12 to 16 more or less distinct spots in punctella, whereas in exquisita these spots are partially confluent, numbering about 6 to 8 (Figs. 1-6). Although both punctella and exquisita are variable in details of forewing markings, neither varies to an extent that field collected series of one include individuals with the wing pattern characteristic of the other.
To what degree these differences reflect different environmental effects acting directly on individuals rather than expression of genetic characteristics of the populations is un- known. O. R. Taylor (in litt.) has shown extreme variability in laboratory stocks and be- lieves there are many temperature labile genes in punctella. Color features, including the quality of orange, amount of melanic reticulation on the transverse yellow areas of the fore- wing, and paleness of the yellow vary with temperature. Taylor stated, for example, that the melanic reticulations all but disappear in the two proximal bands at high temperatures. The existence of reduced melanic lines in exquisita in widespread desert areas would seem to corroborate this correlation, although this feature may be genetically fixed. In addition, frequent occurrence of striking aberrations (Figs. 9, 10) both in the field and in moths reared from field collected larvae suggests caution should be exercised in forming con- clusions about genetic relationships reflected by the various phenotypic expressions.
California exquisita adults vary in color, both in the quality of the orange and in the markings, which range from whitish to yellowish. The individuals that exhibit the palest markings, and therefore approach most closely the type of exquisita, are those reared in January. Those emerging in both spring and fall have pale yellow transverse bands, in- distinguishable from field collected specimens from various localities, including northern Mexico.
During this study no morphological differences could be discovered among several col- lections of Atteva punctella from southern Mexico and the eastern United States. This sup- ports the opinion that aurea (Fitch, 1857) is a synonym of punctella, as was indicated by Zeller (1871), Walsingham (1897), and Forbes (1923). Evidently the persistent use of the name aurea for Nearctic populations of this species by textbooks and most lepidopterists is due to their reliance on Holland's Moth Book and McDunnough's Check List. We concur with Taylor ( 1967) in treating aurea as a synonym.
The separation of exquisita as a species is also suspect, because it is an allopatric coun- terpart in western arid regions and is also very similar in morphological details (including genitalia). Probably exquisita should be treated as a subspecies of punctella pending in- vestigation of the nature of the color differences.
GEOGRAPHICAL DISTRIBUTION
Atteva exquisita is widespread in desert and thorn forest areas of northern Mexico and southwestern United States (Appendix; Fig. 1 1 ). In addition to the type locality, this species has been taken in Nuevo Leon in Northeastern Mexico, while westward, it has been col- lected in the plateau region in southern Chihuahua, and at a number of stations in southern Baja California and along the Gulf of California. It ranges thence northward into southern California and Arizona.
Available information indicates that exquisita, like related species, is restricted to Sim- arubaceae for larval foodplants. The species is more widespread than any genus of Sim- arubaceae in this part of the continent (Standley, 1923), but a complex of essentially allopatric members of the family comprise a distributional pattern corresponding to that of exquisita. Thus the host in Coahuila and Nuevo Leon presumably is Castela (C.) texana (Torrey and Gray), while Alvaradoa amorphoides Liebm. is available in southern Chi- huahua; the moths have been associated with Castela (C.) peninsularis Rose in southern Baja California, with Castela (Eremacantha) polvandra Moran and Felger ( 1968) in the cen-
178
Figure 1 1 . Geographical distribution of A tteva exquisita Busck, according to material cited in the Appendix. Half- closed circles indicating localities where the phenotype of samples suggests a possible blend zone with A. punctella to the north. The type locality (TL) of /I. exquisita, Mobano, Coahuila, is indicated, but this place has not been located on maps we examined.
tral Gulf of California region, and with Castela (Holacantha) emorvi in southern California. This last plant presumably also serves as the foodplant in Arizona.
The most commonly encountered and best known species of American A tteva, punc- tella (= aurea), is widespread in the eastern United States. The species is assumed to be adventitious from some Neotropical area because its host ipXdini, A ilanthus altissima (Mill.) (Simarubaceae) is an introduced ornamental tree from Asia. The plant was brought to North America by way of Europe about 1784 (Davies, 1941), and it adapted and voluntarily spread so that by the middle of the nineteenth century, when the A tteva was first formally noticed, it was widespread in the eastern United States.
A tteva aurea was described by Fitch (1857), who received specimens from a corre- spondent in Savannah, Georgia. Clemens ( 1861 ) redescribed the moth (as compta) based on specimens from Texas. The species was found to be common on Ailanthus in Missouri by Riley ( 1869), and general statements in the literature listed >4. punctella (as aurea) from the Gulf States and thence southwestward. No reports of its presence in the Washington, D.C.— Pennsylvania areas were made by Clemens, Riley, or other early entomologists of the re- gion. Later, occurrence of the species was recorded at Raleigh, North Carolina (Brimley, 1909), at Philadelphia, Pa. (Ilg, 1911), and at Baltimore, Maryland, and in Illinois (Gibson, 1920). The distribution was summarized as New York to Illinois and southward by Forbes (1923). Thus the fragmentary record suggests that the extension to approximately 42° N latitude was the result of spread during the half century between 1870 and 1920. The range may not have expanded much subsequently, but Taylor (in litt.) has seen specimens from Minnesota (St. Paul) and southeastern South Dakota (Yankton). We have specimens from northern Wisconsin (Lake Katherine, Oneida County, H. M. Bower) collected in 1961, which represent the northern record we have seen, about 46° N.
Although Ailanthus is the only host over most of eastern North America, in southern regions three native species of Simarubaceae are available (Small, 1903). In southern Texas Castela texana (Torrey and Gray) is native, while in Florida both Picrannia pentantra Sw. and Simarubra glauca DC. may serve as hosts. The latter is used by a related species, ^//eva floridana Neumoegen, but is not known to be a host plant o^ punctella (Dyar, 1897; Kimball, 1965).
Thus it seems likely thai punctella was not introduced into the United States by man
179
but merely represents a northern component of populations that were native in the West Indies, or Florida and (or) southern Texas. A spread northward, as Ailanlhus became suffi- ciently abundant to support populations, presumably occurred from the nearest geogra- phical areas in which the species lived.
As noted, the close similarity and allopatry of punctella and exquisita suggest that they are geographical components of a single species. The blend zone between the two, or pos- sible sympatric occurrence, is to be expected in southern Texas or areas of Mexico near the Rio Grande. Material for study from this region has been limited. A series from the vicinity of Galeana in southern Nuevo Leon shows a phenotype similar to the type of exquisita in reduction of dark lines in the forewing pattern. However, a single, worn specimen from Val- lecillo, and a good series from 20 miles south of Sabinas Hidalgo in northern Nuevo Leon are less similar. The submedian band is relatively unbroken, as in exquisita, while the post- median band has more extensive dark lines, differentiating about 9 to 13 pale spots, an in- termediate condition between exquisita and punctella (Figs. 7, 8). These specimens lend credence to the supposition that the populations here treated as exquisita represent a west- ern, arid country subspecies of punctella.
BIOLOGY AND BEHAVIOR
Observations were made on plant associations of the moths at the Imperial County, California, site and in two areas of Baja California, on Isla San Francisco in the Gulf of California, and in the vicinity of La Paz. Behavior of the adults was studied in the labora- tory, using reared moths from Coyote Wells and employing glass jar breeding cages with a screen ceiling of nylon (Powell, 1964) or a portable type consisting primarily of a plastic cylinder 17 x 30cm. Larval and pupal habits in the field were recorded only at the Imperial County locality.
Adult.— T)\xx\ng the daytime adults of both sexes were found on the host plant, as well as at flowers of other plants. Diurnal visitation of various flowers has also been recorded for Atteva punctella (Brimley, 1909; Ilg, 1911; Riley, 1869). At Isla San Francisco .4. exquisita was taken in association with Castela peninsularis, a presumed foodplant; at Coyote Wells a few were found on the larval webs and flowers of Castela emoryi; while in the La Paz area adults were visiting flowers of Wislizenia refracta Englem. (Capparidaceae) and two un- identified shrubs. The moths were observed at midday but were not witnessed flying. Sev- eral individuals were taken at light. The species was attracted in numbers to fluorescent blacklight at two localities in Nuevo Leon. Atteva punctella is also commonly collected at lights.
Under laboratory conditions, several groups of adults (totaling about 80 individuals) were caged during a sequence of nine weeks in the summer of 1966 and in January, 1967. Cages were stored in one of three conditions: a) at outdoor temperatures (which in inland Contra Costa County, California, are lower, especially the nightly minima, than would be expected at the Coyote Wells site); b) at variable room temperature ( 15-20 C); and c) in a temperature controlled laboratory at 20 ±1 C Atteva exquisita proved to be a hardy moth, relative to many Microlepidoptera, and successful mating and oviposition were obtained in all three situations. Individual moths lived 4 to 36 days and averaged about 15 days. Mating and oviposition took place primarily during the first few days after caging and neither oc- curred after the tenth day. Females survived in dry vials up to four days, but the moths were observed to take v^ater readily, even during midday, especially after periods when none had been available.
The moths appear to be primarily crepuscular in activity, but some phases of behavior, notably mating, apparently consistently occur at other times in the diel rhythm. Under nat- ural lighting conditions the period of greatest activity of caged adults was about 1730 to 2000 PST, from about 1.5 hours before sunset to 1 hour or more after sunset. Possibly tem- perature was a critical factor in masking normal activity periods, since evenings were cool, usually below 15 C. by nightfall or shortly afterwards. During the late afternoon and dusk period, most individuals actively crawled about the screen ceiling of the cage and occasion- ally flew. At other times of day only occasional moths moved; a reaction to the observer appeared to be a factor. Artificial, overhead lighting aff'ected diurnal activity of exquisita.
180
Individuals exposed to this light condition (in a temperature controlled laboratory) sporad- ically moved about without apparent external stimulus, but neither mating nor oviposition was observed under these circumstances. With the lights off, the same motljs became less active during mid afternoon than they had been while exposed to artificial lighting.
Pronounced activity at the side of the cage towards lights was also noted at night. Therefore, nocturnal observations were made by means of a red-covered flashlight, which did not seem to affect the moths. In outdoor temperature conditions they became inactive by 2030 and 2130, with the temperature at 16 and 13 C. on different evenings, while once when the temperature remained at 19 C. at 2130, the moths were still slowly crawhng. At 2300 with the temperature 13 C. there was no activity, even when a flashlight was directed onto the moths.
Mating by six pairs was observed, at least once in each of the three cage situations. Pairs copulated on the second to seventh day following emergence (average 4.8 days). Under controlled conditions of regular photoperiod and constant temperature (about 22 and 28 C), Taylor (1967) found a long premating period also characteristic in punctella: isolated pairs of virgin moths usually did not mate until the third to sixth day after eclosion. In each case our exquisita pair was witnessed at the onset of morning observations, usually at 0700, but once at 0510 (after daybreak), and the moths remained apparently inactive, in copulo during the morning hours. Separation usually occurred between 1000 and 1 100. In once instance the pair was first observed at 1054, and they separated at 1 148. In at least three examples the moths were known to have been not in copulo late the previous evening, after apparent activity had ceased. Mating did not take place during the crepuscular height of individual movement, and no copulation was observed in the field.
Taylor (1967) found tha{ punclella males' responsiveness and mating occurred chiefly during the first 30 minutes of the light period. Evidently a similar diel rhythm obtains in the mating behavior of exquisita.
Oviposition by exquisita took place in late afternoon. Females engaged in a character- istic behavior pattern, walking slowly, with the abdomen extended and curved ventrad. The extended ovipositor could be seen to press against the twig or protrude through the nylon mesh of the cage ceiling. Oviposition was a slow process, often requiring two to three min- utes at one egg site, and no female was observed to deposit a second egg without moving. Our observations corroborate those of Taylor (1967) on punctella in a controlled environ- ment. He reported that oviposition generally began 1 to 3 hours before the end of the light period and continued into the dark period.
Females of exquisita consistently selected fibrous or pitted surfaces for egg laying. Counts were not made of the various substrates used for oviposition in the cages, but nearly all eggs were deposited on the screen, on the foodplant, especially in partiaUy eaten flowers (Figs. 12, 13), or on the cotton used to hold the foodplant bouquet. A few were placed on the rough wooden floor of the cylinder cage. None were laid on the smooth walls of the breeding cages, where the moths spent most of their time crawling.
Ilg (191 1) stated that eggs of Atteva punctella (= aurea) were distributed through the communal web. We provided females with Castela emoryi which had been cleaned of nearly all the silk webbing. Selection of the cotton and nylon fibers for oviposition suggests that^. exquisita uses the larval webbing in the field.
Riley (1881) reported that the egg of^. punctella was sometimes laid on the web, but generally was attached to the side of the mid-rib of the new leaves of Ailanthus, where it caused a well defined swelling of the leaf vein. Riley attributed this to a toxic substance which he supposed was secreted during oviposition.
Egg.— Eggs of exquisita required 8 to 9 days for development at 20 ±1 C. Groups of eggs were stored in a refrigerator at 4 C five or six days (third to eighth day and about fifth to eleventh day) and their development took 15 to 16 days. Eggs stored in a dry refrigerator for several weeks did not survive.
Larva.— A tendency for larvae of various ages to live gregariously and occupy a com- mon web is characteristic for Atteva {e.g., punctella, (Ilg, 191 1) and fabriciel la (Swed.) in India (Fletcher, 1 920)). Larvae of exquisita produce copious amounts of silk, even in the early instars, and at the Coyote Wells site large inflorescences of the host plant were enmeshed in
181
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fine webbing. Larvae of various sizes were present in the same web in June. Since Castela emorvi is essentially leafless, most of the feeding took place on the flowers and developing seed. Both male and female flowers of the dioecious plant were used, but in late June larvae were more abundant on the staminate inflorescences. Later in the season, after the flowers had dried, overwintering individuals were found only among the seed-bearing in- florescences, where they fed primarily on the seed covers. Moran and Felger (1968) found a similar situation with Castela polyandra in Baja California, where at each of their localities at flowering time, larvae of exquisita "festoon the flowering branches with spidery webs." They noted that larvae also ate the leaves and bark.
In the laboratory newly hatched larvae were able to establish and survive on 25 to 40 day old Castela stems with remnants of flowers eaten by preceding generation larvae. The bark was skeletonized and at times whole twigs were girdled. Similar feeding behavior was reported for Atteva punctella on Ailanthus, a leafy plant, by Riley (1869). Although the Cas- tela branches were kept in water, they appeared dry by the time the first instar larvae began hatching during our study. When first and second instar larvae were placed in vials contain- ing Castela twigs and fresh terminal leaflets of Rhus typhina (Anacardiaceae) from the Uni- versity of California, Berkeley, campus, only the Castela was accepted. A small amount of feeding occurred on the Rhus, but no larvae successfully established on it. A few larvae sur- vived to the penultimate instar on the dry, skeletonized Castela branches, but none reached maturity.
Other first instar larvae were ofl'ered only fresh leaflets of Ailanthus altissima from the University of California, Berkeley, Botanical Garden. Development on Ailanthus was only partially successful, with a small percentage of first instar estabhshment. Once estabhshed, growth occurred at about the same rate as in larvae feeding on Castela stems. The few sur- viving individuals on Ailanthus did not reach maturity, but rearing conditions other than the food may have been critical. Larvae died in the penultimate and antepenultimate in- stars, when 15 to 20 days old.
Larger larvae taken from Castela in May accepted Ailanthus foliage from San Diego and development proceeded successfully. However, penultimate and final instar larvae col- lected in December failed to accept seeds of Ailanthus from Contra Costa County even when these were sliced longitudinally, exposing the soft, inner tissue.
An attempt was made to determine the number of instars through head capsule meas- urements. However, data are mconclusive, owing to lack of material representing the inter- mediate instars. Probably five or six instars are normal, and it is likely that the number diff"ers depending upon circumstances. Larvae subjected to adverse conditions, such as dur- ing winter, may undergo an additional moult. The largest head capsule measurements orig- inate from larvae collected in October and December. There is considerable overlap in the size of the final two instars when individuals representing various seasons are considered
182
15
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Figure 14. Distribution of measurements of head capsule width in la.TVd\ Aiieva exquisiia Busck; based on samples taken in various seasons from one site near Coyote Wells, California. Filled squares indicate head capsules of preserved larvae; cross-hatched squares indicate head capsules shed by pre-final instar larvae; open squares in- dicate head capsule widths of final instar exuviae (estimated byconversion from measurements of frontal triangle).
together (Fig. 14).
Pupa —At maturity larvae construct a frail silken network in which they suspend for pupation. In the field pupae were found within the inflorescence, particularly in lower por- tions of the webbing which the larval colony inhabited. The extremely thin cocoon appears to be a biological feature associated with a behavioral tendency to remain in the communal shelter, and a tendency to wander in the laboratory probably is abnormal. Cocoons also occur in the larval webs in punctella (Ilg, 1911) and A tfevafloridana (Dyar, 1897).
Construction of the cocoon, a quiescent prepupal period, and transformation to the pupa required about 48 hours. Cocoons spun in isolation from other larval webbing were so thin as to be almost invisible. They were rather flat, roughly oval, measuring about 25 X 35mm in outline, with an irregular interior network and a slightly heavier inner cocoon some 15mm in length in which the pupae was suspended, held about 2mm from the sub- strate.
Metamorphosis in the pupa required nine days at room temperatures (approximately 18 to 22 C. daily range).
LIFE HISTORY
There was no indication in the laboratory of either obligate or facultative diapause. Evidently there are at least two or three annual generations, with emergence of adults in late May or June, again in July, and probably at least once more in late summer. Probably extreme summer conditions reduce longevity of adults compared to that in confinement, but, even so, flight periods of generations overlap. By mid-June all stages were present at the Coyote Wells site, and well-defined generations probably are not exhibited from that time on through the season.
Our observations indicate a developmental period of about 40 to 50 days. Thus adults emerging in May could produce a third generation by late August or early September. Sur- vey in October and in late December revealed only larger larvae. No adults, eggs, or pupae could be located. When brought into laboratory temperatures these larvae continued devel- opment, feeding on nearly dry seed covers, and produced adults within a month. Appar- ently individuals resulting from eggs deposited in fall begin feeding and enter a quiescent state, possibly growing slowly by feeding during warm spells in winter, and reach maturity by the time Castela blooms again in spring.
183
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Figures 15-17. Structures of last instar larva oi Aitexa exquisita Busck. 15, setal arrangements on segments 1 and II of thorax, and 1, 2, 6, 7, 8, and 9 of abdomen; SP = spiracle, arrows indicate variable loci. 16, frontal view of head capsule, showing color pattern, black ventral, red-brown median, and orange dorsal. 17, crotchets of abdominal proleg.
Riley (1869) believed that adults o{ Atteva punctella overwintered, because he was unable to obtain oviposition from moths emerging in September and October. Taylor (in litt.) has no data indicating appreciable cold-hardiness in any stage o^ punctella and be- lieves that the species does not overwinter in the northern part of its range.
DESCRIPTION OF EARLY STAGES
f^g'.— Appearing whitish when first deposited, turning pale yellow within 48 hours and gradually deeper yellow prior to darkening of the embryo. Pliable when deposited and assuming variable shapes depending in part upon substrate; on flat surfaces, oval, flattened, somewhat produced towards micropylar end (Fig. 12), varying from about 1.05 X 0.60mm to 1. 15 X 0.65mm; on fibrous and other irregular surfaces, usually somewhat thickened and less regular in outline (Fig. 13). Dorsal surface more or less regularly sculptured with round, shallow pits.
Riley (1881) mentioned the variable form of the eggs xn punciella and indicated that one end frequently was produced into a "short neck." Riley gave the length as 0.9mm, and Peterson ( 1967), who published a photograph of eggs of//, punctella ( = aurea). gave 0.9 X 0.5mm. slightly smaller than anv observed in our study.
La/Tfl-.— First Instar: Head capsule, width 0.27 to 0.31mm; pale when teneral, becoming dark brown, slightly paler towards frontal triangle. Body, length about 2.3 mm when teneral, 3.0 to 3.4 mm when fully fed; integument unpigmented at first, becoming lightly mottled with reddish grav specks, without a distinct pattern. Thoracic shield scarcely discernible; anal shield unpigmented. Setae and pinacula minute and colorless; arrangement apparently very similar to that of final instar. Abdominal proleg crotchets, 6. in an irregular circle; anal proleg crotchets, 8 or 9.
Second Instar: Head capsule, width 0.41 to 0.58mm (possiblv to 0.68mm). dark brown with well defined pale spots on front and crown, corresponding to. but proportionately larger than, those of last instar. Body, length about 3.4 to 4. 1 mm; integument heavily mottled with brownish gray, tending to form dorsolateral bands which contrast with the relatively large, unpigmented DL pinacula. Thoracic shield brown, well defined. Setae relatively elongate, unpigmented. apparently arranged as in final instar. Abdominal proleg crotchets, 10 to 12, uniordinal, in a regular circle; anal proleg crotchets, about 14, irregularly biordinal.
'Description based on specimens from La Paz area of Baja California; females collected in August, 1966. ■Based on specimens from the Coyote Wells site in California; distended in K.A.A.D.; first two instars from eggs deposited by females reared in July; late instars from larvae collected in May. June, and December.
184
Figure 18. Larva and pupa of Aiieva exquisiia Busck. A, Penultimate instar, dorsal aspect. B. penultimate instar. head capsule, anterior aspect. C. pupa, dorsal aspect. D, pupa, ventral aspect. E, pupa, caudal area, showing cre- master structure.
Penultimate Instar: (Figs. ISA, B). Head capsule, width (possibly from 1.05 mm) 1.20 to 1.60 mm; nearly unicolorous, black, at times deep red-brown at crown; round unpigmented spots surrounding setal bases, appear- mg white on the living larva. Body, length about 1 1 to 19 mm; longitudinally striped with orange, black, and white, color pattern variable, consisting of small spots, blotches and irrorations; a broad dorsal band of orange or och- reous-orange( absent on prothora.x), sprinkled with white and dark orange spots, enclosing a thin, mid-dorsal whit- ish line, margined by a fine, broken, black edging; an irregular dorsolateral band of black, subtended by a lateral band of blackish which is heavily sprinkled with white dots and irregular spots; a narrt)w spiracular band of orange runnmg the length of abdomen, lacking on thorax, venter mottled, black and white. The relatively small prolegs banded yellowish and black. Setal arrangement not differing from final instar. Thoracic legs heavily sclerotized, black. Abdominal proleg crotchets, about 26 to 34, in an irregular biordinal tt) triordinai circle; anal proleg crot- chets, about 24 to 28, more or less evenly biordinal.
FINAL INSTAR: Head capsule, width 1.43 to 2.00 mm; black bek)w middle, red-brown to orange at crown, the pattern and extent of black-to-brown marking variable (Fig. 16), spots surrounding setal bases unpigmented, appearing white on the living larva. Body, length about 16 to 25 mm; color pattern variable, similar to penultimate instar, generally less black pigment, with corresponding brighter orange and paler dark bands. Spiracles on ab- dominal segments I to 7 very small, scarcely larger than base of DL seta. Setal arrangements as in Figure 15; pina- culi moderately strongly upraised, whitish; setae unpigmented, mostly elongate, L setae on abdominal segments very small. Abdominal proleg crotchets, about 36 to 40, an irregular arrangement of 18 to 20 large inside a pe- ripheral circle of 18 to 19 small (Fig. 17); anal proleg crotchets, about 32 to 35, a marginal row of 14 to 16 small spurs followed posteriorly by irregularly scattered large crotchets.
185
Setal characteristics ofiwc/uisiia dii nut ditTcr appreciahlv from those given by Mathur ( 1960) in his excellent description of the larva offahriciella (Swed.). This and the partial description ol'punciella given by F\'terson ( 1956) indicate a close similarity in larvae of various species in this genus. The abdominal proleg crotchets apparently are more irregularly arranged in fabriciella. and the anal crotchets are more numerous ( ±43) in that species. Although variable in placement and number to some extent, the abdominal proleg crotchets are more numerous than those of the anal proleg in all instars of exquisiia. whereas the reverse is true in fabriciella according to Mathur.
Pupa.— (Figs. 18C-E) Length about 12 mm: greatest width 3 mm. Subfusiform. head round anteriorly, cauda regularly tapering. Front and sides of head v\ ith a number of hooked anchor setae: front with twt) small, whitish nodules, each with two hooked setae. Antennae and maxillae reaching wing tips, darker than other appendages. General color light brown, with darker shading on several structures, as illustrated: wings with several veins darker than ground color. Dorsum with the longitudinal white lines of larva, considerably obscured; a black longitudinal line lateral to each white line, discontinuous on anterior portion of abdomen, unbroken on caudal segments. Cre- master{Fig. 18E) with numerous, fragile, hooked anchor setae, easily broken: apparently showing no regularity in placement.
Details of the pupal structure of punciclla have been illustrated by Mosher ( 1916).
ACKNOWLEDGMENTS
Our sincere thanks are extended to the following, who assisted in gathering field data during the present study: J. A. Chemsak and J. T. Doyen, University of California, Berkeley: R. V. Moran. who pointed out the Coyote Wells colony, and R. P. Phillips, San Diego Museum of Natural History: and C. E. Norland, San Diego State College.
W. D. Duckworth. U. S. National Museum, provided assistance with the identification of .4 1 leva excpdsiia. and Paddy McHenry, Burbank, California, furnished excerpts of some of the literature. F. L. Blanc, State Depart- ment of Agriculture. Sacramento, supplied early records of exquisita.
O. L. Taylor. Jr.. LIni\ersit\ of Kansas. Lawrence, reviewed a draft of the manuscript and offered many help- ful suggestions along with unpublished data on various aspects of the bionomics of .Aiieva punciella.
Joachim Wolf, assistant on the National Science Foundation project (GB-4014) which supported part of the research program, carried out some of the maintenance and surveillance of the laboratory colonies, and coopera- tion by Anton Crist, University of California, Berkeley, enabled use of plant materials from the Botanic Garden.
Photographs of the eggs were made by A. A. Blaker, Scientific Photographic Laboratory, University of Cali- fornia, Berkeley.
This research was supported in part by grants from the National Science Foundation (NSF-GB-4014, NSF- GB-6813X).
APPENDIX
Data from specimens examined representing /I //eva exquisiia and populations of possible blend with/1. /ji^/jc- tella. MEXICO
Baja California. Norte: Bahia de Los Angeles. VI 1-2-66. on Castela polyandra (R. P. Phillips).
Baja California. Territorio Sur: Isla San Francisco. Golfo de California. IV- 17-62 (C. F. Harbison). 9 mi. SW La Paz. VIIl-10-66.at fis.nisli:eiiiarefracta(i. T. Doyen. J. Powell): VIII-14-66(J. Powell). 21 mi. W La Paz, Vlil- 9-66. at fls. legume shrub (J. A. Chemsak). 26 mi. W.'La Paz. Vlil- 10-66 (J. A. Chemsak). 7 mi. S San Pedro. Vlll- 10-66. at light (J. Powell). Todos Santos. VII-14-57 (D. Spencer. R.. J. & A. Ryckman). 1 mi. SW Punta Palmilla. IX- 14-67, at Bl. & white lights (J. A. Chemsak). 3 mi. N San Jose del Cabo, IX-10. 1 1-67 (J. A. Chemsak).
Chihuahua: 8 mi. NE Hidalgo del Parral, VII- 13-64, at light (J. A. Chemsak, J. Powell).
Coahuila: Mobano (R. Muller). Vallecillo. VI-2-51 (P. D. Hurd).
Nuevo Leon: 20 mi. S Sabinas Hidalgo. VII-7-66 (J. S. Buckett, M. Gardner). 3 mi. E Galeana, VlII-7/9-63 (Duckworth & Davis). UNITED STATES
Arizona: 24 mi. SE Parker, Yuma Co., IX-5-64 (J. Haddock).
California: Hiway 98, 7 airline mi. SE Coyote Wells, Imperial Co., V-22-66, reared from Holacantha emoryi
[(R. V. Moran): VI-1 1-66, reared fVom //. emorvi (C. E. & B. Norland): VI-25-66, on H. emoryi (J. Powell): reared
from//, ewonv, emgd. VI-29to V11-13-66(J. Powell-66FI3); XI 1-25-66, reared from //. ewon;, emgd. 1-18, 19-67
l(C. F. Harbison: JAP-67A6): X-5-67, reared from //. emorvi, emgd. X-1 1-67 (P. A. Opler. J.' Powell. P. A. Rude:
JAP-67K68).
LITERATURE CITED
Brimley, C. S.
1909. List of moths observed at Raleigh, N.Carolina. Ent. News 20: 33-41.
Busck. A.
1912. New Microlepidoptera from Mexico. Proc. Ent. See. Washington 14: 83-87.
Clemens, B.
1861. Contributions to American Lepidopterology. No. 7. Proc. Acad. Nat. Sci., Philadelphia, 1860: 522-547.
186
Davies, P. A.
1941. The history, distribution, and value of Ailanthus altissima in North America. Trans. Kentucky Acad. Sci. 9: 12-124.
Dyar, H. G. *
1897. Oetafloridana Neumoegen. J. New York Ent. Soc. 5: 48.
Fitch, A.
1857. Third report on the noxious and other insects of the State of New York. Trans. N.Y. State Agr. Soc, 1856, 16:315-490.
Fletcher, T. B.
1920. Life histories of Indian insects. Microlepidoptera. Mem. Dept. Agr. India, Ent. Series 6 (1-9), 217 p.
Forbes, W. T. M.
1923. Lepidoptera of New York and neighboring states. Primitive forms, Microlepidoptera, Pyraloids, Bombyces. Cornell Agr. Exp. Sta., Mem. 68, 729 p.
Gibson, A.
1920. Note on the distribution of Altera aurea Fitch. Canadian Ent. 52: 15.
Ilg, C.
1911. The Ufe history ofAtteva aurea Fitch. Ent. News 22: 229.
Kimball, C. P.
1965. Arthropods of Florida and neighboring land areas. Vol. 1. The Lepidoptera of Florida, an annotated checklist. Div. Plant. Indust., Florida Dept. Agr., Gainesville.
Mathur, R. N.
1960. Setal arrangement of y4//evayaZ>n'aW/aSwederus(Yponomeutidae, Lepidoptera). Indian J. Ent. 21:1-5.
Moran, R. and R. Felger
1968. Castela polyandra, a new species in a new section; union of Holacantha with Castela (Simarubaceae). Trans. San Diego Soc. Nat. Hist. 15: 31-40.
Mosher, E.
1916. A classification of the Lepidoptera based on characters of the pupa. Bull. Illinois State Lab. Nat. Hist. 12: 17-159.
Peterson, A.
1956. Larvae of Insects. Lepidoptera and Hymenoptera. Part 1. 3rd ed. Publ. by author, Columbus, Ohio.
Peterson, A.
1967. Some eggs of moths from several families of Microlepidoptera. Florida Ent. 50: 125-132.
Powell, J. A.
1964. Biological and taxonomic studies on tortricine moths, with reference to the species in California (Lepi- doptera: Tortricidae). U. CaUfomia Publ. Ent., vol. 32. 318 p.
Riley, C. V.
1 869. First annual report on the noxious, beneficial, and other insects of the State of Missouri. Missouri State Board Agr., Jefferson City, 181 p.
Riley, C. V.
1881. Lepidopterological notes. Papilio 1 : 106-110.
SmaU, J. K.
1903. Flora of the southeastern United States. Publ. by author, New York City, 1370 p.
Standley, P. C.
1923. Trees and shrubs of Mexico. Oxalidaceae-Tumeraceae. Contr. U. S. Natl. Herbarium 23: 517-848.
Taylor, O. R.
1966. A study of genetics, sperm precedence, and causes of multiple mating iwAtteva punciella (Cramer) (Yponomeutidae, Lepidoptera). Unpubhshed M.S. thesis, U. Connecticut, Storrs.
Taylor, O. R.
1%7. Relationship of multiple mating to fertility in Atteva punctella (Lepidoptera: Yponomeutidae). Ann. Ent. Soc. Amer. 60: 583-590.
Walsingham, T.
1897. Revision of the West Indian Microlepidoptera, with descriptions of new species. Proc. Zool. Soc. Lon- don, 1897: 54-182.
Walsingham, T.
1914. Lepidoptera: Heterocera, Vol. 4. Biol. Centralia Americana: 327-332. lij
Zeller, P. C.
1871. "First annual report on the noxious, beneficial, and other insects of the State of Missouri," by C. V. Riley, 1869 [review]. Stett. Ent. Zeit. 32: 178.
Powell: Department of Entomological Sciences, University of California, Berkeley 94720. Comstock: Deceased subsequent to the writing of the original draft. Harbison: Natural History Museum, San Diego, California 92112.
MUS. COMP. ZOOU LIBRARY
SEP30\974
HARVARD UNIVERSITY LIFE HISTORY OF THE
WESTERN NORTH AMERICAN GOBY,
CORYPHOPTERUS NICHOLSII (BEAN)
JAMES W. WILEY
TRANSACTIONS
OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
VOL. 17, NO. 14 30 OCTOBER 1973
LIFE HISTORY OF THE
WESTERN NORTH AMERICAN GOBY,
COR YPHOPTER US NICHOLSII ( BEAN )
JAMES W. WILEY
ABSTRACT. -The life history of Coryphopterus nicholsii was investigated by field and laboratory studies based primarily on a population at Laguna Beach, California. The species occurs in depths of 61T1 to more than 60m on rock reefs, where it utilizes holes and undercuts in the rock for shelter. Crustaceans (amphipods and copepods) are the major food item; mollusks are also taken in significant numbers. Echinoderms, annelids, mollusks, bryozoans and various eggs are more important food items during fall and winter seasons. Pelagic prejuveniles feed only on copepods. In the study area the sex ratio is 1.7 females : 1 male. Juveniles were first observed on the reefs in February 1967. Length- frequencies and observed scale age groups show 4 to 5 age groups. Paralahrax nebulifer and Lythrypnus dalli prey on C. nicholsii. Sexual dimorphism occurs in the genital papilla, size, length of dorsal and anal fins, and nuptial color of pelvic fins. Breeding extended from mid-February to late August in 1967. Males became ripe at 55 mm, in age-group II and III. Females became ripe at about 47 mm, in age-group II. Ripe ovaries contain two egg groups: ripe and unripe. The total number of ripe eggs in 4 individuals ranged from 3274 to 4788. The spindle-shaped fertilized eggs are attached directly to the overhanging rock surface of the nest. The larvae are pelagic and prejuveniles have been taken far from shore. Juveniles as small as 21.8 mm were found on the reefs from February through August, 1967. The male prepares and guards the nest. In courtship the male rushes at the female and also rises off the bottom a few centimeters with the fins spread, before it settles back down. This species is terri- torial. A hierarchy is established in the laboratory aquarium.
The gobies constitute a widely divergent group of fishes, the suborder Gobioidei. Tliey occur in the tropicaL temperate, and subboreal zones throughout the world, avoiding only the polar regions. Most gobioids are marine, but some inhabit fresh water, including a few in tor- rential streams.
Gobies of the New World genus Coryphopterus are common in the inshore waters of both the tropical western Atlantic and eastern Pacific, inhabiting holes in shallow water coral reefs or rocks. Nine species have been described in the tropical and subtropical western Atlantic. Of the two eastern Pacific species, C urospihis is tropical, but C nicholsii (Bean), the subject of this paper, ranges widely from subtropical to subboreal waters.
STUDY AREA
An intensive field study of Coryphopterus nicholsii was conducted at Laguna Beach, Orange Co., California from September 1966 through January 1968. The study area consisted of two rock reefs: one a shallow, breaking reef which extends down to 10m is approximately 90m offshore; the other varies from 15 to 25m in depth, and is approximately 1200m from the shallow reef, and 800m offshore. Each is approximately 45m long, and is surrounded by sand bottom.
METHODS AND MATERIALS EXAMINED
Tlie population at Laguna was sampled at weekly or biweekly intervals with the use of SCUBA. Most specimens were collected with a slurp gun, although some were taken with "Chem-Fish." Other collections were made in California at Malibu and Palos Verdes, Los Angeles Co.; at Cameo Shores and Aliso Creek, Orange Co.; and at La Jolla, San Diego Co.; and in Baja California, Mexico, at Punta Banda (SW side).
Methods of counting serial parts and taking measurements follow those of Hubbs and Lagler (1958), except that the caudal ray counts follow the methodology of Ginsburg (1945). Tlie last two ray bases of the dorsal and anal fins were counted as one ray. All measurements were taken with dial calipers to the nearest 0.1 mm. Proportions, obtained arithmetically, are presented as ranges and means. All measurements of body length are standard lengths (S.L.).
SAN DIEGO SOC. NAT. HIST., TRANS. 17(14): 187-208, 30 OCTOBER 1973
188
Museum specimens examined were from the following collections: Stanford University (SU); California Academy of Sciences (CAS); Scripps Institution of Oceanography (SIO); Uni- versity of California, Los Angeles (UCLA); Los Angeles County Museum of^Natural History (LACM);and California State College, Long Beach (CSCLB).
BLUESPOT GOBY
Coryphoptems nicholsii (Bean)
Gobius nicholsii. -Bean, 1881: 469 (original description; type locality, Departure Bay, British Columbia; 20 fm.). Jordan and Evermann, 1898: 2218 (specimens recorded from coast of British Columbia). Halkett, 1913: 30, 95 (listed; coast of British Columbia). Fowler, 1923: 293,300 (Malibu Cove, Point Firmin, Newport, Catalina, Isthmus Harbor, Cataling Harbor, Avalon, Santa Cruz, and La Jolla, California). Clemens and Wilby, 1946: 168 (description of type).
Gobius nicholsi. -Jordan and Gilbert, 1882: 946 (coast of British Columbia; description). Jordan and Eigen- mann, 1886: 489, 494, 516, 517 (coast of British Columbia; analysis; listed). Jordan, 1885: 893 (105) (listed). Eigenmann and Eigenmann, 1888: 59 (California; listed). Eigenmann and Eigenmann, 1892: 354 (San Diego, California). Eigenmann, 1892: 130, 159 (Point Loma, California). Jordan and Starks, 1895: 838 (Vancouver Island, British Columbia; listed). Jordan and Evermann, 1896: 456 (coast of British Columbia; listed). Gilbert and Starks, 1904: 176 (mentions Gobius nicholsi in comparing dermal fold of Microgobius emblematicus). Starks, 1911: 211 (listed; San Juan Islands, Washington). Bean and Weed, 1919: 79 (3 specimens - 33, 43, and 47 mm long; taken at Ucluelet, Vancouver Island, British Columbia, during low tide; June-July, 1909).
Gobius nicholsoni (sic). -Eigenmann, 1890: 66 (taken in deep water by the Albatross off Point Loma, Cali- fornia). Eigenmann, 1909: 65 (off Point Loma, California).
Rhinogobius nicholsii. -Starks and Morris, 1907: 223 (San Pedro, California). Starks and Mann, 1911: 16 (San Diego, California; 50 fm.).
Rhinogobius nicholsi. -Snyder, 1913: 459 (Pacific Grove, Cahfornia; description; taken from 10-15 fm.). Gilbert, 1915: 359 (abundant in harbor at Avalon, Catalina Island; taken in shallow water at Monterey, California). Kincaid, 1919: 40 (San Juan Islands, Washington).
Rhinogobiops nicholsii. -Huhhs, 1926: 2 (type of genus; description; Santa Barbara Channel and southwest of Newport, California). Hubbs, 1928: 15 (listed). Ulrey and Greeley, 1928: 20 (Catalina Island, Hunt- ington Beach, Malibu, Newport, Point Firmin, and Santa Cruz, Cahfornia). Jordan, Evermann, and Clark, 1928: 440 (coast of British Columbia, south to southern California). Ulrey, 1929: 10 (listed). Wismer and Swanson, 1935: 34 3; Table 19 (San Juan Channel, Washington; depth 8-1 2m; estimate of numbers of R. nicholsii at 17 fish/2000m2 on dredge and trawl catches). Schultz, 1936: 122, 191; fig. 16 (key; figure showing ventral side; British Columbia to southern California). Barnhart, 1936: 81; fig. 245 (description; San Clemente Island to British Columbia; sometimes taken in more than 2100 feet). Schultz and DeLacy, 1936: 137, 213 (British Columbia to southern Cahfornia; Hood's Canal near Holly, Washington; marine; not rare; San Juan Island, Washington). Clemens and Wilby, 1946: 5, 29, 167-168; fig. 103 (key;hsted; range, English and Nanoose bays, Barkley Sound at Ucluelet, Esperanza Inlet on west coast of Vancouver Island, Skidegate Channel, Queen Charlotte Islands; 20 fm. or more; description). Limbaugh, 1962: 552 (La Jolla, California; colonizing newly exposed reefs).
Coryphoptems nicholsii. -Ginshurg, 1938: 113 (no locahty; differences from Coryphoptems urospilus). Ginsburg, 1945: 136, 137 (C nicholsii used in study of fin-ray count methodology). McAllister, I960: 38 (listed). Miller and Lea, 1972: 186 (figure; description; key; range - south of Point Rompiente, Baja California, to Skidegate Channel, Queen Charlotte Island, British Columbia; depth 5 to 80 feet).
Coryphoptems nicholsi. -Huhhs and Follett, 1953: 34 (listed). Limbaugh, 1955: 26, 35, 120 (southern Cali- fornia; observed in "sand-bottom holdfast biotope" and "kelp rock-bottom biotope"; preferred southern Cahfornia habitat sand near rocks; 1-180 feet; description; observed at following localities - Pacific Grove, Yankee Point, Goleta, Point Dume, EI Segundo, Rocky Cove, Newport Beach, San Clemente, and La Jolla; and at San Miguel, Santa Rosa, Santa Cruz, Anacapa, Santa Catalina, Los Coronados, and San Martin islands). Bohlke and Robins, I960: 103, 105 (key; characteristics; discussion of genus). Ebert and Turner, 1962: 249-252 (ecology; breeding habits; behavior; description of eggs and embryos). Pequegnat, 1964: 272 (Corona del Mar, California; abundance on reef). Carlisle, Turner and Ebert, 1964: 15, 28, 73, 77 (listed; observed on artificial reefs and offshore oil installations, and in Santa Monica Bay, California; spawned on Redondo Beach, California artificial reef; listed - Seal Beach, Rincon, Summerland, Redondo Beach, and Paradise Cove, California). Best and Oliphant, 1965: 101 (listed; Point Arguello, California). Turner, Ebert and Given, 1965: 109, 112 (listed, San Elijo Lagoon, San Diego County, California). Berry and Perkins, 1966: 676 (distribution of pelagic prejuveniles). Turner, Ebert and Given, 1966a: 16, 17, 18, 19, 26-27, 29; tables 1-4 (abundance; distribution on benthic quadrats; listed as abundant; Point Loma, California). Turner, Ebert and Givfen, 1966b: 40, 47 (distribution around Orange Co., California sewer outfall pipeline; relative abundance of goby in vicinity of outfall). McCart, 1967: 433-434 (scale regener- ation). Fitch, 1967: 4, 16; fig. 3 (lower Pleistocene otoliths). Fitch, 1968: 2, 21-22; fig. 2s (early Pleis- tocene otoliths). Turner, Ebert and Given, 1969: 185 (habits on southern California artificial reefs). Macdonald, 1972: 91 (cephalic-lateralis system). Quast, no date (a): 4, 6; table 1 (listed among species ranging from boreal into temperate waters; British Columbia through north temperate; 0-130 feet; listed as member of southern California rocky-inshore zone fauna).
189
Bohlke and Robins (1%0) referred to this species as Coryphopterus nicholsi. Although it stands alone in the group, Bohlke and Robins accept it in Coryphopterus. Tliey indicated that should C. nicholsii be treated as subgenerically distinct, the name Rhinogobiops Hubbs would apply.
Figure 1. Coryphopterus nicholsii. Adult male, 86.5 mm in standard length, from Laguna Beach, Orange Co., California.
Diagnosis. -Coryphopterus nicholsii (Fig. 1) is easily distinguished from all other species of Coryphopterus by having more soft dorsal, anal, and pectoral rays, more scales, and in having a narrow wedge of scales reaching a point above the anterior margin of the opercle.
Description. -h has an elongate, moderately stout body. Greatest body depth 4.1-6.1 (5.17) in standard length. Body slightly compressed, width 5.7-10.6 (7.26) in standard length. Head moderate, wider than deep; head width 1.2-2.1 (1.50) in head length; head length 3.0-4.2 (3.56) in standard length. Cheeks not tumid. Mouth small and terminal. Lower jaw projecting. Maxilla not reaching to point below anterior margin of eye, 1.9-3.2 (2.58) in head length. Jaw teeth conical, in bands, enlarged in both an outer and inner row. Tongue truncate at tip. Eye directed superolaterally and large (diameter 2.5-4.3 (3.42) in head length). Bony interorbital very narrow. A high, thin and nearly vertical crest on top of head from behind eyes to origin of spinous dorsal fin. Rows of papillae on sides of head moderately developed. No barbels (Fig. 12). Slit behind fourth gill-arch reduced; pseudobranchiae exposed. Branchiostegals 5 (1 on epihyal). Pelvic fins fully united, free from belly, each with 1,4 rays. Pectoral fins with 21-24 (22.3) rays, none silky. Dorsal fins barely separated, VI-I, 12-15 (13.8). Caudal fin broadly rounded, 17: 12 segmented, branched rays and a variable number of segmented, unbranched rays and simple (procurrent) rays. Some specimens with 2 above and 1 below segmented, un- branched rays, plus 2 simple rays below occur about as frequently as those with 2 above and none below segmented, unbranched rays, plus 3 simple rays — 1 above, 2 below. Rarely the caudal elements composed of 1 2 branched, segmented rays with above and below 1 unbranched, segmented ray, plus 1 above and 2 below simple rays. Anal 1, 1 1-14 (12.1). Body completely scaled except in predorsal midline. Head scaleless. Scales of sides each with a comb-like row of marginal spines, a submarginal focus, and basal radii. Scales in oblique rows, 23-28 (25.6) at midline. No lateral line. Shoulder girdle without papillae. Color: pale orange-olive or light yellow, with irregular vertical purplish brown streaks developed at time of death or in social interaction. Body irregularly flecked with metallic blue-green. Iridescent stripe below eye, giving rise to vernacular name - bluespot goby. Tip of first dorsal jet black. Pelvic fin of breeding male black.
OCCURRENCE
Coryphopterus nicholsii ranges from Point Rompiente (27°N), Baja California to Skide- gate Channel (530N), Queen Charlotte Island, British Columbia (Miller and Lea, 1972;McCart, 1967). It is common in this area and its range may be more extensive than is currently reahzed.
190
Otoliths of C. uichohii have been found in many southern CaHfornia Pliocene and Pleis- tocene deposits. More than 1 ,700 have been recovered from the Lomita marl (Pliocene) at San Pedro, and others have come from Timms Point silt, San Pedro sand (Lower I^eistocene) and Baldwin Hills, Los Angeles (Upper Pleistocene) (Fitch, 1967, 1968).
GENERAL ECOLOGY AND NATURAL HISTORY
Coryphopterus nicholsii inhabits shallow water, from 6m to more than 60m. After a pelagic oceanic existence as larvae and early juveniles, individuals assume a benthic habit. The preferred habitat appears to be a rock-reef area, but small groups of rocks on the open sand are also inhabited. The greatest concentrations occur near the periphery and in the channels of the reef, where the rock meets the surrounding sand bottom; in these areas there are numerous undercuts and holes, into which this goby can find safety. It is seldom found more than 25 cm from protective cover, but is common on the open sand or rubble bottom in front of its shelter. The open area around the hole serves as a feeding and display site.
Coryphoptenis nicholsii is also found over the tops of reefs, particularly in areas having many holes, ledges, or thick gorgonian cover. Using the protective cover of the gorgonian canopy, individuals may venture more than a meter from their home shelter.
MORPHOMETRICS
The meristics of C. nicholsii from the sampled areas are rather uniform (Table 1 ). How- ever, pectoral ray counts from British Columbia are lower than those from the southernmost locality (Isla San Martin).
Pelagic prejuveniles were sampled in southern California from San Pedro Basin, San Juan Seamount, and between Anacapa and Santa Cruz Islands. Variation in the pelagic prejuveniles was similar to that in the juvenile-adult sample with the exception of the first dorsal spines and scale counts. For the scales the explanation is one of delayed development. Variation in dorsal spines between the age groups may be the result of delayed development or perhaps some spines were overlooked.
Morphological data for three localities were considered in size groups in Table 2. Although adequate samples were not available from Baja California or British Columbia, no notable trend of morphological variation was evident. Differences in proportions were observed in fin ray lengths. As C. nicholsii exhibits sexual dimorphism of some body parts (particularly fins) morphological comparisons should be made on the basis of individual sex, but sample sizes were inadequate for such analyses.
FOOD HABITS
Food studies were conducted to identify the major foods, to determine if differences in seasonal utilization occurred, and to disclose any variation in the foods taken by fish of different sizes. Tliree methods of analysis were used: numerical, volumetric, and frequency-of- occurrence. Of the 106 stomachs examined, two were empty, and were not included in the calculations.
It appears that crustaceans are the principal food item of C. nicholsii (Fig. 2); they were found in nearly all stomachs examined, generally in the greatest numbers, and formed the bulk of the volume. Numerically crustaceans comprised 90.9% of the food items; mollusks (4.8%) were second. Other food items, such as annelids, echinoderms, etc., were usually found in small numbers.
By volume crustaceans made up 79.0% of the diet; mollusks again were second (4.6%). Other foods composed a small portion of the diet.
Crustaceans occurred in 97.0%> of the stomachs analyzed (Fig. 2). Although found in small quantities numerically and volumctrically, mollusks occurred in 63% of stomachs examined. Bryozoans, which accounted for only 0.4% of total food volume, were found in 37% of stomachs examined. As this goby was not observed to selectively bite off pieces of bryozoans on the reefs it is possible that these organisms were picked up incidentally along with the pre- ferred bottom-dwelling food items. Bryozoans are relatively indigestible and are probably re- tained in the gut for some time, which may account for their apparent abundance.
191
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Table 2. Comparison of morphometries among populations of Coryphopterus nicholsii
Punta Banda, Baja California
Laguna Beach, California
Hunt Island, British Columbia
Proportions
S.L. N Range Mean N Range Mean N Range Mean
standard length
|
head length |
22-39mm |
11 |
3.0-3.4 |
(3.30) |
39 |
3.0-3.6 |
(3.30) |
|||
|
40-55 |
17 |
3.1-3.8 |
(3.39) |
56 |
3.1-3.7 |
(3.40) |
||||
|
56-75 |
18 |
3.2-4.0 |
(3.60) |
86 |
3.3-3.9 |
(3.46) |
9 |
3.6-3.9 |
(3.75) |
|
|
76-92 |
26 |
3.3-4.2 |
(3.65) |
17 |
3.3-4.0 |
(3.76) |
||||
|
standard length |
||||||||||
|
body width |
22-39mm |
11 |
5.7-8.4 |
(7.46) |
37 |
7.0-10.6 |
(8.48) |
|||
|
40-55 |
9 |
6.7-7.8 |
(7.33) |
45 |
6.1-8.7 |
(7.25) |
||||
|
56-75 |
17 |
6.6-8.1 |
(7.35) |
51 |
5.9-8.5 |
(6.60) |
||||
|
76-92 |
28 |
5.9-8.8 |
(7.28) |
|||||||
|
standard length |
||||||||||
|
length base 1st dorsal |
22-39mm |
11 |
5.7-6.4 |
(6.17) |
39 |
5.3-7.2 |
(6.28) |
|||
|
40-55 |
14 |
4.7-5.8 |
(5.30) |
51 |
4.9-7.1 |
(5.67) |
||||
|
56-75 |
18 |
5.1-6.1 |
(5.59) |
75 |
4.9-6.2 |
(5.41) |
10 |
5.0-6.0 |
(5.50) |
|
|
76-92 |
23 |
4.6-6.1 |
(5.20) |
17 |
4.8-6.1 |
(5.25) |
||||
|
standard length |
22-39mm |
11 |
3.4-4.0 |
(3.80) |
39 |
3.4-4.1 |
(3.82) |
|||
|
length base 2nd dorsal |
||||||||||
|
40-55 |
15 |
3.4-3.8 |
(3.58) |
54 |
3.0-3.8 |
(3.56) |
||||
|
56-75 |
18 |
3.4-4.2 |
(3.74) |
76 |
3.3-3.9 |
(3.51) |
10 |
3.5-3.8 |
(3.64) |
|
|
76-92 |
23 |
3.2-4.0 |
(3.54) |
17 |
3.3-4.2 |
(3.67) |
||||
|
standard length |
||||||||||
|
length base anal |
22-39mm |
11 |
3.9-4.9 |
(4.69) |
38 |
3.4-4.8 |
(4.78) |
|||
|
40-55 |
13 |
4.3-4.9 |
(4.54) |
49 |
3.9-5.1 |
(4.61) |
||||
|
56-75 |
18 |
4.4-4.8 |
(4.56) |
79 |
4.1-5.0 |
(4.69) |
10 |
4.4-4.8 |
(4.56) |
|
|
76-92 |
24 |
4.0-4.9 |
(4.52) |
17 |
4.2-5.0 |
(4.54) |
||||
|
standard length |
22-39mm |
11 |
3.0-3.6 |
(3.40) |
38 |
3.1-3.9 |
(3.51) |
|||
|
length of longest pectoral ray |
||||||||||
|
40-55 |
16 |
3.3-3.9 |
(3.46) |
52 |
3.1-4.3 |
(3.60) |
||||
|
56-75 |
18 |
3.1-4.0 |
(3.51) |
70 |
3.1-4.0 |
(3.69) |
3 |
3.1-3.2 |
(3.17) |
|
|
76-92 |
21 |
3.2-3.9 |
(3.55) |
17 |
2.8-3.5 |
(3.22) |
||||
|
standard length |
22-39mm |
11 |
2.4-2.8 |
(2.53) |
28 |
2.4-2.5 |
(2.45) |
|||
|
length of longest 2nd dorsal ray |
||||||||||
|
40-55 |
16 |
3.2-3.7 |
(2.74) |
11 |
2.1-2.5 |
(2.32) |
||||
|
56-75 |
18 |
2.0-2.2 |
(2.15) |
34 |
1.9-2.4 |
(2.23) |
3 |
2.0-2.1 |
(2.03) |
|
|
76-92 |
18 |
1.9-2.3 |
(2.10) |
17 |
1.7-2.0 |
(1.89) |
||||
|
standard length |
||||||||||
|
body depth |
22-39mm |
11 |
4.4-5.4 |
(4.97) |
39 |
4.5-5.9 |
(5.18) |
|||
|
40-55 |
16 |
4.5-5.5 |
(4.98) |
50 |
4.4-5.9 |
(5.35) |
||||
|
56-75 |
18 |
4.6-5.6 |
(5.00) |
73 |
4.1-6.1 |
(5.05) |
3 |
4.9-5.3 |
(5.10) |
|
|
76-92 |
23 |
4.5-6.1 |
(5.27) |
17 |
4.8-5.9 |
(5.39) |
||||
|
standard length |
22-39mm |
11 |
4.0-4.4 |
(4.21) |
39 |
4.1-4.7 |
(4.40) |
|||
|
length of longest pelvic ray |
||||||||||
|
40-55 |
3 |
4.3-4.5 |
(4.37) |
11 |
4.1-5.1 |
(4.48) |
||||
|
56-75 |
4 |
3.9-4.6 |
(4.38) |
28 |
3.5-5.1 |
(4.55) |
3 |
4.2-4.8 |
(4.44) |
|
|
76-92 |
19 |
4.3-4.8 |
(4.66) |
17 |
3.9-4.5 |
(4.25) |
||||
|
standard length |
22-39mm |
3 |
2.8-3.4 |
(3.03) |
35 |
2.9-3.0 |
(2.97) |
|||
|
length of longest anal ray |
||||||||||
|
40-55 |
3 |
2.6-2.8 |
(2.74) |
12 |
2.7-3.4 |
(2.89) |
||||
|
56-75 |
4 |
2.6-2.8 |
(2.75) |
28 |
2.4-3.0 |
(2.74) |
3 |
2.5-2.7 |
(2.56) |
|
|
76-92 |
17 |
2.3-2.9 |
(2.56) |
16 |
2.1-2.7 |
(2.18) |
||||
|
head length |
22-39mm |
4 |
2.5-3.2 |
(2.65) |
35 |
2.4-3.2 |
(2.82) |
|||
|
length upper jaw |
||||||||||
|
40-55 |
16 |
2.3-3.1 |
(2.66) |
56 |
2.3-3.2 |
(2.86) |
||||
|
56-75 |
7 |
2.4-2.9 |
(2.64) |
77 |
2.1-3.2 |
(2.55) |
3 |
1.9-2.8 |
(2.40) |
|
|
76-92 |
22 |
2.2-2.7 |
(2.44) |
16 |
2.3-2.7 |
(2.45) |
||||
|
head length |
||||||||||
|
head width |
22-39mm |
4 |
1.6-1.7 |
(1.62) |
36 |
1.5-2.1 |
(1.75) |
|||
|
40-55 |
16 |
1.3-1.7 |
(1.49) |
59 |
1.4-1.8 |
(1.51) |
||||
|
56-75 |
7 |
1.3-1.5 |
(1.43) |
77 |
1.2-1.8 |
(1.42) |
3 |
1.4-1.5 |
(1.43) |
|
|
76-92 |
24 |
1.2-1.6 |
(1.37) |
17 |
1.3-1.7 |
(1.54) |
||||
|
head length |
||||||||||
|
snout length |
22.39mm |
4 |
3.5-4.9 |
(4.06) |
36 |
3.3-4.5 |
(3.84) |
|||
|
40-55 |
15 |
3.2-4.0 |
(3.51) |
56 |
3.2-3.9 |
(3.42) |
||||
|
56-75 |
7 |
3.1-3.9 |
(3.34) |
78 |
2.9-4.0 |
(3.57) |
3 |
2.9-4.5 |
(3.63) |
|
|
76-92 |
22 |
3.1-4.0 |
(3.45) |
17 |
3.5-4.4 |
(3.99) |
||||
|
head length |
||||||||||
|
length of eye |
22-39mm |
4 |
3.2-4.3 |
(3.52) |
35 |
3.1-3.8 |
(3.30) |
|||
|
40-55 |
15 |
2.9-3.8 |
(3.04) |
54 |
2.9-3.9 |
(3.36) |
||||
|
56-75 |
7 |
3.1-3.9 |
(3.46) |
78 |
2.9-4.2 |
(3.52) |
2.5-3.3 |
(2.97) |
||
|
76-92 |
24 |
3.3-4.0 |
(3.61) |
17 |
3.1-3.6 |
(3.45) |
193
Echinoderms (mainly sea urchin spines and tests) were also found in relatively high fre- quency (26%), probably for the reasons discussed for bryozoans. The nutritional importance of bryozoans and echinoderms is seemingly small.
CRUSTACEANS
MOLLUSCS
ANNELIDS
UNIDENTIFIED EGGS
ECHINODERMS
BRYOZOANS
Si9^^$^s$C!$S!$?s$s^s^$s^ff^^
i
k
^
[
S NUMERICAL 7o ■ VOLUMETRIC % n OCCURRENCE %
— r— 25
50
— r- 75
100
Figure 2. Analysis of 106 stomach contents of Coryphoptems nicholsii taken at Laguna Beach, California, from October 1966 to September 1967.
CRUSTACEANS COPEPODS ISOPOOS AMPHIPODS OSTRACODS DECAPODS CUMACEANS UNIDENTIFIED
MOLLUSCS PELECYPODS GASTROPODS
ANNELIDS
ECHINODERMS
PORIFERA
BRYOZOANS
COELENTERATES
VERTEBRATES
MISC. EGGS
Figure 3. Further analysis of the stomach contents of Coryphoptems nicholsii expressed as numerical and frequency-of-occurrence percentages.
194
Measurements and counts from the moUusks were taken with the shell intact. However, for accurate evaluation, only the digestible parts should be considered. This was not possible, because of the small size of the food items. Because mollusk shells are relatively undigestible, and they may be retained in the stomach, data for this element are probably biased. Some shells may have been picked up incidentally along with the substrate as the goby grabbed for a desired bottom-dwelling organism. Empty gastropod shells could also be the shelter of hermit crabs, an important part of the decapod element of the diet. The crabs are presumably digested rapidly, whereas the shells may accumulate in the gut. These emptied hermit crab shelters would then be categorized as a mollusk element even though the food item selected by the goby was a crustacean.
Amphipods (39.9% numerically) and copepods (19.6% numerically) were the most abun- dant crustaceans taken by C. nicholsii (Fig. 3). One stomach contained 256 amphipods. Iso- pods (3.6%) and decapods (6.8%) also made up an important part of the diet.
Amphipods were found in 88% of the stomachs examined. Copepods (74%), decapods (73%) and isopods (55%) were also found in most stomachs (Fig. 3). Although pelecypods and gastropods composed only 2.5% and 2.3% of the total number of food items respectively, pele- cypods were found in 49% and gastropods in 47% of all stomachs examined (Fig. 3).
|
CRUSTACEANS |
.SSQS8S!3< |
KiSSS^SSS |
>^^^\^^\\^\^^l |
||
|
■■■■■■1 |
|||||
|
MOLLUSCS ANNELIDS UNIDENTIFIED EGGS ECHINODERMS BRYOZOANS |
|||||
|
1 |
|||||
|
1 |
k- |
] |
S NUMERICAL % |
||
|
UJ QQ C9 |
^^ |
■ VOLUMETRIC % n OCCURRENCE % |
|||
|
y |
|||||
|
wm |
|||||
|
c |
Sv:::. |
||||
|
( |
25 |
50 75 |
10 |
||
|
CRUSTACEANS MOLLUSCS UNIDENTIFIED EGGS BRYOZOANS |
K^«S?Nfi?SISS«J2«5?je^;SS»5^^ |
||||
|
OS |
i^:::;;:iii;;;;;;:;:i;h;;::;; ■ j |
||||
|
ea UJ |
F |
||||
|
UJ |
:;:::S---::i |
||||
|
CO 1 |
|||||
|
^ |
1 |
||||
|
a. |
? |
||||
|
c |
1 |
||||
|
25 |
1 1 50 T> |
U)l |
Figure 4. Seasonal analxsis of the stomach contents of Coryphopterus nicholsii.
Coryphoptenis nicholsii exhibited seasonal variation in food utilization (Fig. 4). Crus- taceans were the major food item in both the October-March sample (numerical: 87. 7%; volu- metric: 66.0%) and the April-September sample (numerical: 94.0%; volumetric: 95.5%). Mollusks apparently became more important in October-March (numerical: 4.5%; volumetric: 4.6%) as compared to April-September (numerical: 5.3%; volumetric: 1.5%). The other food classes, e.g., echinoderms,annelids,'etc., also became more important during the Fall and Winter.
195
The frequency analysis also showed a similar pattern of seasonal food use (Fig. 4). Crus- taceans were found in 86% of the October-March stomachs and 98% of the April-September stomachs. Mollusks were found in 70% of the October-March samples, but in only 58% of the April-September samples. Thirty-two percent of the October-March stomachs contained echino- derms, but only 18% of the April-September stomachs contained this food.
Benthic organisms, such as mollusks, echinoderms, annelids and bryozoans, were found more frequently in the October-March period. Also in the October-March sample the crustacean element shifted somewhat to more benthic forms such as decapods, cumaceans, and ostracods, with concomitant decreases in copepods and other swimming and planktonic forms. Tliis shift in diet perhaps reflected changes in populations of the latter groups.
Copepods composed 100% (N = 47) of the food of four pelagic postlarvae (18.7-21.1 mm) from the San Juan Seamount, California. One stomach contained a single scale. No gross dif- ferences in diet were noted between size classes or sexes once the gobies had assumed a benthic existence.
POPULATION STRUCTURE
Tlie Laguna population showed a sex ratio of 1.7 females to 1 male (165 females and 96 males). The sex ratio seemingly fluctuated somewhat, but the paucity of data for some months precluded a complete analysis.
Scales provided satisfactory material for aging C. nichohii, and scale analysis demonstrated the relation between age and size (Fig. 5). Modes in the length-frequency distributions agree well with the observed ages, although overlap occurs due to the differential growth and pro- longed spawning period.
V-
IV-
« III-
UJ
C9
II-
I-
STANDARD LENGTH, MM
Figure 5. Empirical growth rate of Coryphopterus nicholsii from Laguna Beach, California, based on scale analysis of 134 specimens collected from October 1966 through January 1968. Vertical line represents mean; horizontal line, the range of variation; longer rectangle, one standard deviation on either side of the mean; shorter rectangle, 2 standard errors on either side of the mean.
196
Young gobies were first observed on the Laguna reefs in February. Tliese individuals, which ranged from 21.8 to 26.2 mm in standard length, were probably ones that had hatched the previous year. Growth during the pelagic period is considerable as the newly-hatched larvae measure under 3.0 mm in total length.
Scales of C. nicholsii form during the pelagic period. One specimen showed some well developed scales at 19.5 mm on 28 December 1966. However, the majority of specimens did not show scales until they had attained a length of 21 .1 mm or greater. This is the approximate size at which C. nicholsii settled on the reefs in 1967. Tlie first annulus is not laid down until the following winter.
Tlie observed length-frequencies of C nicholsii coWeciQd. at Laguna Beach (Fig. 6) usually corresponded with the observed age-groups indicated by scales in that five (sometimes four) frequency groups were represented in the samples. Males of any frequency group were rela- tively larger (as indicated by mean standard length) than females of the same group.
r^1n II r^rlnrn n 1^ n
JAN.
r^ nn n n h
EL
^^^
IL
FEB.
AFInnnn nr^ A nP-n P^^^ h I ^n F^ n 'f\
MAR.
n^n n^^r^rnnTiJi^ n./\
JUNE
_L1
pJl^r^n n^^hn h^nn
RJl
JULY
f^npJI .
IL
rXnrnnr^^
AUG.
5-
0 5 0 10 5H
Ik
h
JhL
SEPT.
A
^
OCT.
^nnnn jl
^ ySF^
^
j^
NOV.
X
I
r^ , n K^^^^ r^ . /h
DEC.
20 30 40 50 60 70
STANDARD LENGTH. MM
80
90
Figure 6. Length-frequency measureihents of 1325 specimens of Coryphopterus nicholsii taken at Laguna Beach, Cahfornia, from October 1966 through September 1967.
PREDATION
One incident of predation on C. nicholsii was observed on the shallow Laguna reef. A small sand bass {Paralahrax nebulifer) caught and ate a Coryphopterus after I flushed the goby away from the shelter of the reef onto the surrounding open sand. Subsequent collections of
197
22 sand bass on the reef revealed that 7 (32%) had fed on C. nichohii. Turner, Ebert and Given (1969) did not find C. nichohii in the stomach of large predaceous fish collected on reefs be- tween 1960 and 1963, although this goby was abundant and appeared to be a suitable food item. Smith (1970) and Quasi (n.d.b.) list Gobiidae as a food of kelp bass (Paralabrax clathratus).
Stomach analyses of bluebanded gobies, Lythrypnus dalli, another common inhabitant of the southern California rock reef, revealed larval C. nicholsii in 2 of 42 (4.8%) stomachs. Investigations were not made on the food habits of other possible predators on the reefs inliabited by C. nichohii.
Turner, Ebert and Given (1969) observed a 3 mm larval C. nichohii entrapped in the hydranth of an Obelia on an artificial reef off southern Cahfornia.
SEXUAL DIMORPHISM
Sexual dimorphism of the genital papilla, is usually evident in the Gobiidae (Dotu, 1957a, 1958a, 1961a; Miller, 1963; Springer and McErlean, 1961 ; Tavolga, 1954; Smith, 1964;Weisel, 1947). Dimorphism has also been noted in fin size (Hildebrand and Cable, 1938; Baird, 1965; Dotu, 1958b, 1959, 1961b), pigmentation (Heincke, 1880; Tavolga, 1954;Ninni, 1938;D6tu, 1958c, 1961c), shape of mouth (Baird, 1965), and size and shape of the body (Breder and Rosen, 1966; Baird, 1965; Dotu, 1957b, 1958c, 1961c).
Four hundred specimens of C. nicholsii from 9.6 to 88.0 mm in standard length were examined for external sex identification. The genital papilla was found to be sexually dimorphic (Fig. 7). Specimens shorter than 25 mm standard length could not be accurately sexed extern- ally, but those larger than 25 mm were correctly sexed by examination of the papilla, which is elongate and pointed in the male and is broad and truncate in the female.
During the breeding season the males of C. nichohii are easily distinguished from the females by their black pelvic fins. These fins remain light grey throughout the year in the females.
83.0 mm. S.L.
Gl.Omm.S.L.
Figure 7. Sexual dimorphism in the genital papilla of Coryphoptems nicholsii.
Dimorphism is also discernable in the maximum sizes of the sexes. Males attain a greater length than females. The largest male examined was 90.0 mm in standard length, whereas the largest female was 76.0 mm. Larger size may accord the nest-guarding male greater success in the protection of the eggs.
Examinafion of the length of the second dorsal and anal fins of mature gobies also re- vealed sexual dimorphism. Both fins were found to be relatively longer in the male (Fig. 8). Measurement was from the front of the base of the first element to the distal end of the last ray. Tliis dimorphism was not expressed in meristic differences.
198
REPRODUCTION
The Laguna population was sampled at weekly or biweekly intervals from October 1966 to September 1967 to determine the length of the breeding season. The presence of eggs and individuals of both sexes in breeding condition was used as evidence of reproductive activity.
CO
2.0 2.1 2.2 2.3 2.4
2nd Dorsal in Standard Length
Oct 09
23 24 25 2.6 2.7 2.8
Anal Fin in Standard Length
Figure 8. Sexual dimorphism in length of the second dorsal and anal fins of Coryphoptenis nicholsii, from anterior of base to posterior tip of last ray; expressed as ratio of length of fin into standard length.
Females of C. nicholsii were found to be mature at 47.3 mm or larger (Fig. 9). This size corresponds to age-group 11 as observed from scale and length-frequency analysis. Mature males shorter than 55 mm were not found. This size corresponds with the last of age-group III. How- ever, mature males were found with two or more annuli (age-groups III througli V). Ripe females were found in age-groups II througli V.
o a>
4- 3- 2 1
0
cr
• — Mature *— Immature
• — ••
• — • — •'
— I ' I I I I
20 30 40
7
I ■ ' I 50
— p— 60
70
80
Standard Length in Millimeters
Figure 9. Standard lengths of Coryphoptenis nicholsii at sexual maturity based on gonad development of 22 males and 43 females from Laguna Bcach, California.
199
Tlie first ripe females, measuring 47.3 to 73.5 mm in standard length, were taken on 10 February 1967. Tlie first ripe males appeared slightly earlier on 2 February 1967; they ranged from 72.1 to 83.0 mm in standard length. No ripe gobies of either sex were found after 26 August 1967 (Fig. 10).
c»o»-« ©•o»o»- o» o w^ o • o •
' Mar. ' Apr. ' May ' June ' July ' Aug ' Sep. ' Oct ' Nov ' Dec '
Jan ' Feb
MONTH
Figure 10. Monthly percentages of ripe Coryphoptents nicholsii from Laguna Beach, CaHfornia. Based on 1134 specimens taken from Laguna Beach, California from October 1966 through September 1967. Solid dots (solid line) represent males, circles (broken line) represent females.
The mature ovaries contained two egg groups, one ripe and one unripe. The ripe egg group seemed to be spawned at one time. The number of ripe ovarian eggs (in both ovaries) was found in four individuals to range from 3274 to 4788. However, the assessment of fecundity in a species which may spawn several times over an extended period, has little bio- logical value per se. I could not determine how many times this species spawned in a season.
Ripe ovarian eggs are orange and round, and measure 0.4 to 0.7 mm. Unripe eggs range in diameter from 0.05 to 0.2 mm.
Eggs were found on the Laguna reefs from 1 1 April to 5 August 1967. However, because it is difficult to locate the nests, I do not think that these dates wholly encompass the spawning period. Ebert and Turner (1962) observed nests off Hermosa Beach and Santa Monica, Cali- fornia, from April through October.
200
Fertilized eggs (Fig. 1 1) have the spindle shape characteristic of gobies. They are attached directly to the rock surface but have no adhesive threads. Ebert and Turner (1962) found that mature eggs averaged 2.10 mm long by 0.48 mm wide. The embryo within eqph mature egg averages 2.97 mm in length and its head is directed opposite (downward from) the pole of attachment on the lower surface of the nest. Ebert and Turner described the developing embryo.
Fertilized Egg Mass Section
A..
Fertilized Egg
2.2 mm.
Figure 1 1 . Fertilized eggs of Coryphopterus nicholsii.
Tlie prejuvenile of C. nicholsii (Fig. 12) is pelagic. Specimens ranging in size from 15.5 to 29.0 mm standard length have been taken 560 km off San Francisco and 260 km off Santa Barbara. One individual was taken on Davidson Seamount, 97 km southwest of Point Sur, California (Berry and Perkins, 1966). These individuals have been described by Berry and Perkins as pelagic, oceanic, protracted prejuvenile stages. Specimens from the vicinity of San Diego ranging from 9.6 to 22.6 mm in standard length, have been examined. These were dis- tinct from the adults in having vertical bars which are burnt orange in life. These bars become light brown in alcohol.
Juveniles of C. nicholsii were found to assume a benthic habit on the Laguna study reefs at 21.8 mm standard length. Specimens as short as 24.0 mm were found on other reefs. Fish of this size were found on the Laguna reefs in February through August 1967.
Figure 1 2. Pelagic prejuvenile of Coryphopterus nicholsii, 1 9.4 mm in standard length, from San Pedro Basin, California.
201
FEEDING BEHAVIOR
Coryphoptems nicholsii has three feeding-behavior patterns. The most frequent was swimming off the bottom for a distance of about 8 cm, grabbing a small crustacean and then settling. Another pattern involved picking a benthic organism from the substrate. The third involved picking up a mouthful of the loose bottom, spitting it out, and then selecting the desired food as it fell through the water. By the latter two methods such items as decapods, annelids, and echinoderms were taken. These items were probably detected visually, although this species does have moderately developed papillae (Macdonald, 1972) which may function in sensing burrowing organisms.
I noted one exception to the general benthic habit on the southwest coast of Punta Banda, Mexico, where there are many narrow canyons through which strong upwelling currents flow. Gobies there hovered 0.5 to 1.0m off the bottom, using their pectoral fins as the means to counter the current, as they fed on the plankton that drifted up the canyons.
In the aquarium, C. nicholsii was fed on frozen brine shrimp. Usually the gobies grabbed the shrimp in midwater, and swallowed them whole. If the shrimp was picked off the bottom the goby would spit it out with the associated rubble and then once again grab the shrimp as it drifted downward. When fed on chunks of frozen smelt, which were too large to be swallowed whole, the gobies, which have moderately developed teeth, bit off large pieces.
BREEDING BEHAVIOR
Gobies and species of various other groups endowed with adherent eggs generally seek some rocky crevice, shell, or other hard object suitable for egg attachment. As is typical of gobioid fishes, and most territorial fishes, the male C. nicholsii selects and prepares the nest (Tavolga, 1954; Dotu, 1958a; Guitel, 1893). Nest building is intermittent, alternating with courtship and other phases of social behavior. The male enters and leaves his shelter frequently. The duration of the stay within the shelter is highly variable.
Nest preparation consists of several cleaning movements, similar to those described by Tavolga (1954) for Bathygobius soporator: fanning, rubbing, scooping, and nibbling. Fanning the most frequent act, consists of the vigorous waving of the body and pectoral fins, sending up a cloud of sand for several seconds. This appears to be the most efficient type of digging activ- ity for this fish. Rubbing consists of brushing the body against the algae-covered surface of the nest, apparently to dislodge this material. Scooping is accomplished by taking mouthfuls of sand, small shells, or other debris and carrying it away from the nest. Nibbling may occur if the shelter has algae or other material clinging to its surface. Nest cleaning is not thorough and the adhesive algae and other organisms are not cleaned off completely.
Essentially the same nest-preparation movements observed in C. nicholsii have been described for other species of gobies, as well as for most teleosts that construct any sort of hollow in sand substrates. The fanning method of nest formation is probably the most wide- spread of the nesting behaviors in fishes and has been described for the Centrarchidae (Breder and Rosen, 1966), certain cichlids (Baerends and Baerends-Van Roon, 1950), and Clinocottus and other cottids (Breder and Rosen, 1966).
When courting, each male rose a few centimeters off the bottom, spread his fins fully, and settled back to the substrate. After one to several of these displays, he swam back to his nest, where he continued nest construction for a short time, and then resumed his courting.
Intermittently the male swam swiftly toward the female and then quickly returned to his starting place, apparently in an attempt to stimulate the female and to attract her to his nest site. If the female reacted negatively, the male followed and continued courting, often nipping and chasing her. Early in courtship the female simply darted away into other shelters. Prior to spawning the female often took shelter in the male's nest, from which she was chased. However, the male, upon seeing the female within the nest, approached with courting movements before entry and chasing. Apparently the male faced a conflict situation between defense of his nest and enticing the female to remain and spawn. Occasionally a female approached a male that was courting her. The female then slowly undulated the body, gaped, and spread the fins.
Some form of courtship behavior is exhibited by males of most nesting species of fishes. There is considerable interspecific variation in the details of this behavior within gobiids. The
202
courting male of Gobius munitus exhibits body tremors and rapid breathing movements while approaching the female with short hops, his fins bristling, head raised, throat puffed, and mouth agape (Guitel, 1892). Males of Gobiosoma approach the female with short darts, with fins widely spread (Breder, 1942). Courting males of Brachygobius xanthozdnus swim back and forth in front of the female (Field, 1945). Tlie courtship display of a male Elacatinus oceanops consists of violent swimming while he clings to the substrate with the pelvic cup; he then butts the female in the head and genital regions with his nose, and slaps her on the head with his caudal fin (Feddern, 1967). The male of Batliygobius soporator slowly approaches the female and positions himself beside or in front of her; he then waves his body, tail, and pec- torals in a manner similar to that involved in nest cleaning; if the female moves away, the male follows and continues courting, often chasing and nipping her (Tavolga, 1954).
A change in the color of the pelvic fin of Coryphoptenis nicholsii males during the breed- ing season presumably stimulates courtship response by the female. Color changes have been noted in various fins of other gobiid fishes during the breeding season (Dotu, 1956;Kinzer, 1960). Tavolga (1954) showed that Bathygobius soporator females can at times "recognize" males by coloration, in the absence of any courtship activity. Tliat the male's black pelvic fin may provide adequate stimulus for sexual recognition was suggested in an experiment wherein an adult female with artificially blackened pelvic fins was approached by a ripe female showing definite courtship behavior.
The female C. nicholsii attaches her eggs to the underside of the nest. Tlie deposited egg masses average 10 cm in diameter, are roughly circular and are made up of a single layer of eggs. The male is intermittently present in the nest at the time of oviposition, where he frequently circles the female, butting and bitting her. He often passes his turgid genital papilla over the surface of the eggs. Fertilization apparently takes place during and immediately after oviposition.
Among the gobies whose nesting habits have been described, oviposition on the underside of shelters is quite common. Fishes that hide and nest under shelters are likely to be confronted with a nest floor which consists of sand, mud, rubble, or other irregular surfaces, whereas the ceiling will probably present a hard surface more suitable for the adherence of eggs. Also such shelters offer a degree of safety against egg predators.
Tavolga (1950) found that unless artificially fertilized eggs of Bathygobius soporator ?lxq placed in a hanging position many of the embryos do not rotate properly within their elongate egg cases. Such individuals develop with their heads pointed toward the attached end of the shell and are thus unable to hatch.
Spawning completed, the male of C nicholsii defends, cleans, and fans the eggs until they hatch. He fans the eggs by intermittently waving his body and pectoral fins. This movement resembles that of nest preparation, and produces a strong current of water over the eggs. Tlie residing male rushes out to chase away any goby or other organism that approaches the nest, as well as a slurp gun placed in front of the nest.
The male guards the eggs in the majority of nesting fishes (Breder and Rosen, 1966). Among the gobies, only Typhlogobius is reported as an exception, in that both sexes guard and fan the spawn (MacGinitie, 1939). Brood care by the male of C nicholsii consists almost exclu- sively of fanning with some or all of the fins. Brood care is practiced by most nesting fishes. Tlie function of the brooding is three-fold: circulation of water for respiration, prevention of bacterial and fungal growth, and defense of the eggs. Tavolga (1954) proposed another func- tion in that the fanning activity of the male in some way prevents the abnormal positioning of the embryos within the eggs.
SOCIAL BEHAVIOR
Coryphopterus nicholsii is a bottom dweller. Its swimming activity is confined to short, quick spurts for feeding, for territory defense, and for escape to shelter. Although it is able to change color and pattern according to the habitat, its light color is generally retained even in dark, rocky areas. This light color blends well with the sand bottom, which appears to be the preferred substrate type of this goby. Tlie black eyes and tip of the first dorsal, although con- spicuous to the human observer, may serve as disruptive markings, breaking up the shape of the goby before a predator.
203
Like many other gobies (Stebbins and Kalk, 1961; Tavolga, 1954), C. nicholsii exhibits territorial behavior. It is a solitary species that sets up a territory that includes a shelter and a feeding-display area in front of it. Tlie juxtaposition of the territories, which may be spaced less than 25 cm between shelter centers, induces numerous encounters between neighboring individuals, hi the aquarium any available shelter, including a tank corner, was utilized and fought over. The species was quite aggressive in a tank containing several fish; there was almost continuous nipping and chasing.
Figure 13. Changes in coloration of Coryphopterus nicholsii during social interaction. A. Normal light color- ation of undisturbed or dominant individual. B. Intermediate darkening of submissive goby. C. Final darkened coloration of submissive goby. Note light spot under eye. This spot is blue in life and gives rise to the ver- nacular name, biuespot goby.
204
A variable nip order was established which was somewhat, but not absolutely, correlated with size (see also Bopp, 1957; Tavolga, 1954). Social orders were established very quickly. During the breeding season, spawning males, which were the largest individuals, appeared to be dominant. Subdominant members retreated to higher levels of the aquarium, hanging on the tank walls and corners by means of continuous swimming movements of the fins and by the suction of their fused pelvic fins. Some attempted to jump out of the tank.
The fundamental color of C. nicholsii is uniform pale yellow, but the coloration is vari- able, changing rapidly in response to different social situations. During social interactions the subordinate animal usually becomes much darker, and is mottled (Fig. 13). One subordinate individual which had been displaced from the bottom of the tank took up a position three- fourths of the way up the tank wall next to the filter siphon which had evenly spaced holes with growths of dark algae. The color pattern of the fish quickly matched that of the siphon holes. This individual held this position and retained this color pattern for several days.
i^.^
Figure 14. Combat-threat posturing behavior of adult males of Coryphopterus nicholsii in aquarium.
The highest degree of aggressive behavior was observed in encounters between mature fish of about equal size. The two gobies approached each other with slow undulations of the body, and with all fins stiffly erected. They positioned themselves next to one another, directly head on (Fig. 14), or head to tail. The mouth was then widely gaped, with the throat expanded and the head elevated. The two gobies displayed either alternately or simultaneously. The "loser" assumed the mottled color pattern and dashed to the safety of shelter.
Interactions between fish of different sizes, or after a hierarchy has been established, usually involve a quick dash by one of the fish, the more dominant one, with the other fish retreating. The more dominant fish nips the fins and scales of the retreating individual. In the laboratory, the fish of the higher rank continually attacked the subordinate intruders if the tank was not large enough to provide adequate territories for the gobies present.
Pugnacity, a feature common to gobies and most territorial fishes, is expressed in C. nicholsii as a simple type of biting and pursuit behavior between combatants. Guitel (1892) described similar darkening, throat puffing, gaping, and fin stiffening in Gobius minutus. Breder (1942) reported that males of Gobiosoma robustum exhibit darkening and fin spreading as intimidation mechanisms. Tavolga (1954) found Bathygobius sporator also exhibits color changes correlated with fighting and with reproductive behavior, especially in males, and that extreme darkening is characteristic of fighting males; this occurs together with throat puffing, gaping, quivering, butting, and biting movements. Weisel (1947) found that intimidation be- havior o[ Gillichthys mirabilis consists almost entirely of the display of its huge gape.
ACKNOWLEDGMENTS
I am grateful to Dr. David W. Greenfield, my major sponsor, for his assistance and stimulation in every phase of this study. I'or help in the field, I should like to thank Jack C. Turner, David M. Wildrick, and Dannie A. Hensley. Dr. Philip Adams deserves special thanks for his assistance in the laboratory and field. Robert J. Lavenberg provided the specimens of pelagic prejuveniles. I wish to thank Dr. Bayard Brattstrom and Dr. Kenneth L. McWilliams for their suggestions and critical reading of an early draft of the manuscript. Dr. Carl L. Hubbs ottered many helpful suggestions for the manuscript. Terry Greenfield typed the manu- script and helped in the laboratory, for which I am very grateful. My wife, Beth, provided the illustrations.
205
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California State University, Fullerton, California 92631. Present address: 16341 Skymeadow Drive, Placentia, California 92670.
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MUS. COM P. ZOOU LIBRARY
SeP30S74
HARVARD UNIVERSITY.
ANE\N PLATYDOR/S (GASTROPODA: NUDIBRANCHIA) FROM THE GALAPAGOS ISLANDS
DAVID K. MULLINER AND GALE G. SPHON
TRANSACTIONS
OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
VOL. 17, NO. 15 12 APRIL 1974
A NEW PLATYDORIS (GASTROPODA; NUDIBRANCHIA) FROM THE GALAPAGOS ISLANDS
DAVID K. MULLINER AND GALE G. SPHON
ABSTRACT. — Platvdoris carolynaen. sp. is described from the Galapagos Islands and compared with the two eastern Pacific species of PlatyJoris and with P. scabra. the only member of this genus with wide distributional limits. Platydorids are rasping sponge feeders that live in tropical and temperate oceans. The distribution and nomenclature of the 36 known species is reviewed briefly.
The nudibranch fauna of the Galapagos Islands has been neglected by previous workers. Apparently, only two species, Doris peruviana Orbigny 1837 and Onchidium k'slici Stearns 1893, have been reported (Pilsbry and Vanatta, 1902: 556; Stearns, 1893: 383). Yet, in March 1971 members of the Ameripagos Expedition to the Galapagos Islands collected at least 15 species of nudibranchs, some of them fairly common, at various localities in the islands (Sphon and MuUiner, 1972). Included among these was a previously undescribed species of Plat}'doris that was found at several localities, and which may be endemic to these islands. In this paper, we describe this new species, and briefly review the distribution and nomenclature of Pkitydoris.
BIOGEOGRAPHY
Members of the genus Pkitydoris are sluggish, retiring invertebrates that cling tightly tc crevices on the underside of rocks and coral heads. They are found in tropical and temperate waters from 40° N latitude to 32° S latitude. All but one of the thirty-six known species have limited ranges, usually consisting of one shoreline, one island chain, or one location (Fig. 1). Platydoris scabra (Cuvier, 1804) is the exception, ranging in tropical waters from 38° E longitude to 155° W longitude.
The majority of the platydorids are found in the Indo-Pacific. They are rasping sponge-feeders, and the great abundance and diversity of sponges may account for the large number of platydorids found in these seas as compared to the Atlantic or Eastern Pacific.
SYSTEMATICS
Order Nudibranchia
Family Dorididae
Genus Pkity^doris Bergh, 1877
Definition. — The body is leathery, flattened, and oval with a coarse to smoothly granular mantle. The foot is notched anteriorly. The branchial aperture is oval and six- lobed. There is no labial armature, and the radula consists of numerous hamate teeth. The stomach is large; the penis is armed with small spines, and the vagina has a thick cuticular lining (translated and modified after Bergh, 1877).
Type species. — Platydoris argo (Linnaeus, 1758), by original designation.
Platydoris carolynae n. sp.
Type locality. — Docking area, Charles Darwin Research Station, Santa Cruz Island, Galapagos Islands, Ecuador, (0° 45' 05" S, 90° 15' 38" W).
Description. —The ground color of the animal is cream, the entire dorsum mottled with black or brown blotches. The ventral side of the mantle is also cream with black or brown spotting, each spot made up of multiple fine cross-hatched lines. The rhinophores are tan-colored with dark brown spots. The branchiae are translucent with dark brown or
SAN DIEGO SOC. NAT. HIST., TRANS 17(15): 209-216. 12 APRIL 1974
210
140" 120° IOC 80° 60° 40* ?0° W 0° E 20' 40° W
100° 120° 140° 160° E 180° W 160° 140°
Figure 1. Distributional records for Platydoris scabra are indicated by the solid dots. Numerals represent the number oi Platydoris species found at each locality.
black specks (Fig. 2).
The rhinophores are perfoliate with twenty-four leaves. They are completely retract- able and set in a rhinophoral pit with a seven-lobed margin. The branchiae are completely retractable, tripinnate, six in number and divided into two groups of three. The anterior end of the branchial opening forms a crenulate lobule. The pharynx extends for approxi- mately half the distance from the anterior end of the foot to the edge of the dorsum.
Two small head tentacles are attached to the head between the mantle and the body. No eyespots are visible. The foot is bilabiate anteriorly to just behind the foot corner, notched medially. The radula is approximately heart-shaped with 76 longitudinal rows of hamate teeth. No rachidian teeth are present. The radula formula is 76 x 70.0.70 (Figs. 3, 4). In the reproductive system the spermatocyst is elongated, connecting directly into the mucus and albumen gland. A short convoluted tube connects to the oval spermatheca. The prostate is large and globular. The penis is armed with erect, slightly curved spines. The vagina is lined with thick cuticle-bearing folds (Fig. 5).
Ety^mology. — This species is named for Carolyn Stover, a member of the Ameripagos Expedition.
Type material. — Holotype, California Academy of Sciences, Invertebrate Zoology Type Series No. 303. Photographs of the living animal are deposited in the CASIZ slide collection as Nos. 153-155. The specimen, which is 46.4 mm long and 32.5 mm wide was collected by Andre DeRoy on 13 February 1964, intertidally at the Charles Darwin Research Station dock.
Paratypes (7). — One specimen deposited at the Charles Darwin Research Station, collected intertidally in shallow pools on Santa Cruz Island. One specimen deposited at the Los Angeles County Museum of Natural History, Invertebrate Zoology. Type Collec- tion No. 1619, collected intertidally at Duncan Island, by the Ameripagos Expedition on 26 March 1971. Two specimens deposited at the San Diego Natural History Museum, Department of Marine Invertebrates: SDSNH No. 62826, collected from 10m at Jervis Island by the Ameripagos Expedition on 24 March 1971; Radula slide and dissected animal SDSNH No. 62827, collected from 6m off Punta Alfaro, Isabella Island, by the Ameripagos Expedition on 25 March 1971. One specimen deposited at the American Museum of Natural History, Department of Living Invertebrates, AMNH No. 173729, collected from 10m, off Jervis Island, by the Ameripagos Expedition on 24 March 1971. One specimen deposited at the United States National Museum of Natural History, type Collection No. 735349, collected from 6m off Punta Alfaro, Isabella Island, by the Ameripagos Expedition on 26 March 1971. One specimen deposited at the Delaware Museum of Natural History, No. 64524, collected at Long Beach on the northern coast of Santa Cruz Island by Sue Andrews on 21 December 1972. The paratypes range in size from 19.5 mm long and 14.2 mm wide to 42.3 mm long and 28.0 mm wide.
Discussion. — The only species of Platydoris known from the eastern Pacific are P. tnacfarhmdi Hanna, 1951, and P. punctatella Bergh, 1898. The three species are separ-
211
Figure 2. Platydoris carolynae, dorsal (top) and ventral (bottom) views.
able by external appearance and geographical range. Platydoris macfarlatidi is known only from the type lot of four specimens dredged from 172m off Pismo Beach, San Luis Obispo County, California. It is dark red, velvety smooth, with no spots or markings on the surface. The foot tapers to a point posteriorly. Platydoris punctatella is from "Isia de Pajargo", Chile (? = Isla de Pajaros, Chile, ca. 26° S. lat.). It is pale yellow. The rhino- phores and the anterior margin of the foot are bright yellow. The back has a few scattered
212
Figure 3. Radula with offset drawings of individual teeth.
light brown spots and flecks. The underside of the mantle is smooth and taint yellow with no markings.
Platydoris carolytuie is known only from the Galapagos Islands. The foot is round posteriorly in contrast to P. nnicfurlandi. The color is cream or white with brown or black mottling on the dorsum. Each of the spots on the ventral side of the mantle is made up of fine cross-hatched lines. Platydoris punctatella has no ventral markings.
Internal differences were noted in P. carolynae. The radula formula is 76 x 70.0.70 for a 46 mm animal, whereas the radula of a 50 mm P. scuhra is less elongated, 49 x 103.0.103. The vas deferens in P. scuhra is long and coiled, whereas it is short and straight in P. carolynae.
THE SPECIES OF PLATYDORIS
We have been able to find 46 specific names described as. or later assigned to Platy-
213
doris in the literature. Of these, one (P. variolata) has been shifted to Anisodoris; eight are currently considered synonyms; and two are nomina nuda. The remaining names are listed alphabetically in Table 1. Synonyms are cited chronologically under the currently accepted name. We have also indicated the distribution of each species and have added the two nomina nuda at the end of the list, as they both appear to be undescribed species.
TABLE 1. Currently recognized species of Platydoris and their distributions.
SPECIES
DISTRIBUTION
P. angustipes (Morch, 1863)
Synonyms:
P. angustipes alaleta (Bergh. 1877a)
P. rubra White. 1952 P. argo (Linnaeus, 1767) (Type species of the genus)
P. canariensis (Orbigny, 1839)
P. capricomensis Allan, 1932
P. carinata Risbec, 1928
P. cruenta (Quoy and Gaimard, 1832)
Synonym:
P. arrogans Bergh, 1877a P. dura Pruvot-Fol, 1951 P. ellioti (Alder and Hancock, 1864) P. flammulata Bergh, 1905 P. formosa (Alder and Hancock, 1864) P.'galhanus Burn, 1958 P. hi'patica (Abraham, 1877) P. herdmani Farran, 1905 P. immonda Risbec, 1928 P. incena Eliot. 1904 P. inframaculata (Abraham, 1877) P. infrapicta (Smith. 1884) P. laminea Risbec, 1928 P. macfarlandi Hanna, 1951 P. murrea (Abraham, 1877) P. noumeae Risbec, 1928 P. papiUata EHot. 1904 P. philippi Bergh. 1877a P. pukhra Eliot. 1904 P. punctata (Orbigny, 1839) P. punctatella Bergh, 1898 P. sanguinea Bergh, 1905 P. scahra (Cuvier, 1804) Synonyms:
P. coelestis (Kelaart, 1858)
P. I'urychlamys Bergh. 1877a
P. coriacea (Abraham, 1877)
P. vicina Bergh, 1880
P. in-dalci Allan. 1932 P. sordida (Quoy and Gaimard. 1832) P. speciosa (Abraham. 1877) P. spinulosa Farran. 1905 P. spongllla Risbec. 1928 P. striata (Kelaart, 1858) P. townscndi EWot. 1905 P. variolata (Orhigney. 1837)
See: Anisodoris variolata (Bergh. 1898) P. varicgata Bergh, 1880
NOMINA NUDA P. hnumca Bergh. 1877a P. niarniorata Bergh. 1877b
Southern Florida, Bahi'a, Brazil.
through Caribbean, and south to
Mediterranean Sea. Also, a questionable report from the East Indies. Canary Islands.
Capricorn Group, Queensland, Australia. New Caledonia.
Western Pacific, Japan, Philippine Islands, and East Indies.
Mediterranean Sea.
Indian Ocean and southeast coast of India.
East Indies.
Eastern Indian Ocean; also, reported from Hawaii.
Southern Australia.
Riciniola (Pacific Ocean).
Ceylon.
New Caledonia.
Zanzibar.
Ceylon and East Indies.
Queensland, Australia.
New Caledonia.
Central California.
Mauritius, Indian Ocean.
New Caledonia.
Eastern Africa.
Mediterranean Sea.
Eastern Africa.
Canary Islands.
Isla de Pajaros, Chile.
East Indies.
Indian and western Pacific Oceans.
Mauritius, Indian Ocean.
Western Pacific Ocean.
Ceylon.
New Caledonia.
India and Japan.
India.
Central Chile.
Tahiti.
Although this is the type locality o\ P. hcpatica. as given by Abraham (1877). we have been unable to locate such a locality from available gazetteers.
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Figure 4. Scanning electron micrographs from a section of the radula at 3a. Left, X400; right, XQOO.
_-- — P*"
mg —
a--
1.0mm
Figure 5. Camera-lucida drawing of reproductive organs with offset of a cirral hook, hd-hermaphrodite duct, sc-spermatocyst. st-spermatheca. pr-prostate, vd-vas deferens, v-vagina, p-penis, od-oviduct, mg-mucus gland, a-albumen gland, am-anipulla, eg-external genital opening.
215
ACKNOWLEDGEMENTS
We wish to thank the Charles Darwin Research Station and its Director, Peter Kramer, for making it possible for the Ameripagos Expedition to collect in the Galapagos Islands.
We also wish to thank Allyn G. Smith, Department of Invertebrate Zoology, California Academy of Sciences for lending specimens and photographs.
Joe Nakanishi of the Los Angeles County Museum of Natural History prepared the illustrations of the dorsal and the ventral views of the holotype; Anthony D'Attilio of the San Diego Natural History Museum drew the reproductive organs and the radula; Michael Featherby made the SEM photographs. James Lance helped with the literature search and offered technical advice. George E. Radwin read the manuscript, offered technical advice, and extracted and mounted the radula. Thanks are also due to the Ameripagos Expedition members for their collecting help and companionship.
LITERATURE CITED
Abraham, P. S.
1877. Revision of the anthobranchiate nudibranchiate Mollusca, with descriptions or notices of forty-one hitherto undescribed species. Proc. Zool. Soc. London, 1877, p. l%-269, pis. 27-30. Alder, J. and Hancock, A.
1864. Notice of a collection of nudibranchiate mollusca made in India. Trans. Zool. Soc. London 5: 113-147, pis. 28-33. Allan, J.
1932. Australian nudibranchs. Australian Zool. 7(2): 87-105, pis. 4, 5. Bergh, R.
1877a Malacologische Untersuchungen, Nudibranchiaten. /// C. G. Semper, Reisen im Archipel der Phil- ippinen. Sect. 2, 2(12): 495-546. pis. 58-61.
1877b Kritische Untersuchung der Ehrenberg' schen Doriden. Jahrb. Deutsch. Malakoz. Ges. 4: 45-76.
1880. Malacologische Untersuchungen, /// C. G. Semper, Reisen im Archipel der Phiiippinen. Sect. 2, 4(1): Suppl. (1) 1-78, pis. A-F.
1898. Die Opisthobranchiata der Sammlung Plate. Zool. Jahrb. Suppl. 4(3): 481-582, pis. 28-33.
1905. Die Opisthobranchiata der Siboga-Expedition. Monographic 50: 1-248, pis. 1-20. Burn, R.
1958. Further Victorian Opisthobranchia. J. Malacol. Soc. Australia 2: 20-36, pis. 6, 7. Cuvier
1804. Suite de I'extrait des memoires sur les mollusques. Bull. Sci. Soc. PhiJom. Paris. 3(93): 254-256, pi. 22. Eliot, C.
1904. On some nudibranchs from East Africa and Zanzibar. Part III. Proc. Zoo). Soc. London, 1903, p. 354-385, pis. 22-24.
1905. Nudibranchs from the Indo-Pacific. 1. Notes on a collection dredged near Karachi and Maskat. J. Conch. 11(8): 237-256. pi. 5.
Farran, G.
1905. Report on the opisthobranchiate mollusca collected by Professor Herdman, at Ceylon, in 1902. Report to the Government of Ceylon on the pearl oyster fisheries of the Gulf of Manaar. Suppl. Rep. 21: 329-364, pis. 1-6. Hanna, G. D.
1951. A new west American nudibranch mollusk. Nautilus 65(1): 1-3. Kelaart, E. F.
1858. New and little known species of Ceylon nudibranchiate molluscs and zoophytes. J. Roy. Asiatic Soc, Ceylon Branch, Colombo 3(9): 76-111. Linnaeus, C.
1767. Systema Naturae, 12th ed., pp. 1-1367. Marcus, E. and E. Marcus
1960. Opisthobranchia aus dem Roten Meer und von den Malediven. Akad. Wiss. Lit. Abh. Math.
Naturwiss.. 12: 873-933. 1967. American Opisthobranch Molluscs. Studies in Tropical Oceanography No. 6: Inst. Mar. Sci., Univ. Miami, Florida pp. i-viii + 1-256, 1 pi. Morch, O.
1863. Contributions a la faune malacologique des Antilles Danoises. J. Conchyl. (3) 11: 21-43. Orbigny, A. D.
1835-46. Voyage dans I'Amerique Meridionale. Mollusques pp. 1-758, pis. 1-85.
1839. Mollusques. echinodermes, foraminiferes et polypiers, recueillis aux lies Canaries par Mm. Webb et Berthelot. Mollusques 1. 2(2): 1-117, pis. 1-28. Pilsbry, H. A. and E. G. Vanatta
1902. Papers from the Hopkins Stanford Galapagos Expedition, 1898-1899. XIII, Marine Mollusca. Proc. Washington Acad. Sci. 4: 549-560. Pruvot-Fol, A.
1951. Etudes des nudibranches de la Mediterannee. 2. Arch. Zool. Exper. Gen. Paris 88: 1-80. pis. 1-4. Quoy, J. R. and Gaimard, J. P.
1832. Voyage de decouvertes de I' Astrolabe . . . pendant les annees 1826-1829 sous le commendemcnt de M. J. Dumoni D"Urville, Zool. 2: 1-686, pis. 1-26 (1833).
216
Risbec, J.
1928. Contribution a I'etude des nudibranches Neo-Caledoniens. Faune des Colonies Francaises 2(1): 1-328, pis. 1-12. Smith, E. A. ♦•
1884. In: MoUusca. Report on the zoological collections made in the Indo-Pacific Ocean during the voyage of H. M.S. 'Alert' 1881-1882. Trustees of the British Museum. London, pp. 34-116, pis. 4-7. Sphon, G. G. and D. K. Mulliner
1972. A preliminary list of known opisthobranchs from the Galapagos Islands Collected by the Ameripagos Expedition. Veliger 15(2): 147-152. Steams, R. E. C.
1893. Scientific results of explorations by the U.S. Fish Commission steamer Albatross. No. XXV. -Report on the mollusk-fauna of the Galapagos Islands with descriptions of new species. Proc. U.S. Natl. Mus. 16(942): 353-450, pis. 51, 52. White, K. M.
1952. On a collection of molluscs from Dry Tortugas, Proc. Malacol. Soc. London 29(2-3): 106-120, pi. 6.
Contribution No. 153 of the Charles Darwin Foundation for the Galapagos Islands.
Mulliner: Department of Marine Invertebrates, Natural History Museum, San Diego, California 92112.
Sphon: Invertebrate Zoology, Los Angeles County Museum of Natural History, Los Angeles, California 90007.
SAN
MUS. COMP. ZOOL. LIBRARY
SEP Q 10"'/1
HARVARD UNiVERSITY
THE DISTRIBUTION AND ECOLOGY OF MARINE BIRDS OVER THE CONTINENTAL SHELF OF ARGENTINA IN WINTER
JOSEPH R. JEHL, JR.
0^
I
TRANSACTIONS
OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
28 JUNE 1974
VOL. 17, NO. 16
THE DISTRIBUTION AND ECOLOGY OF MARINE BIRDS OVER THE CONTINENTAL SHELF OF ARGENTINA IN WINTER
JOSEPH R. JEHL, JR.
ABSTRACT. — Quantitative data on the distribution and abundance of marine birds in winter were obtained on three transects of the coastal shelf of Argentina in 1971 and 1972. On the basis of avifaunal assemblages, the shelf waters can be divided into two zones, the boundary occurring near the southern edge of Golfo San Jorge (47° S). Spheniscus magellanicus, Puffinus griseus. and Sterna hirundinacea were characteristic of the northern zone; Fulmarus glacialoides. Eudyptes crestatus, Pelecanoides magel- lani, Diomedea exulans/ epomophora. and Pachyptila sp. of the southern zone. Beyond the continental shelf off northern Argentina the avifauna was similar to that over the southern shelf, but included several additional species: Garroidia nereis. Procellaria cinereus. and Pelecanoides urinatrix.
Winter sea bird populations along the coast of Argentina appear to be established by mid-June and to remain stable through the winter. In general, abundances seemed low and concentrations were found mainly in areas of strong mixing or upwelling. The winter census data are compared with those from a brief summer transect. Despite pronounced shifts in the ranges of individual species, there was little seasonal difference in total sea bird abundance. A preliminary ecological study indicated that the bulk of the sea bird biomass through the entire year is contributed by large species that obtain their food from the upper meter of the sea, mainly by surface seizing. However, marked seasonal and latitudinal differ- ences in patterns of resource utilization appear among divers, plungers, and filter feeders.
Circumstantial evidence suggests that oil pollution is a major cause of sea bird mortality, particularly over the northern shelf.
Although sea birds are among the most conspicuous inhabitants of the ocean, their role in marine ecosystems has received little attention (Ashmole, 1971). Basic information such as population sizes at different seasons, species composition of sea bird flocks, and periods of migration are prerequisites for ecological analysis. While such data are slowly beginning to accumulate (e.g., King, 1970), they are inadequate if not entirely lacking for most parts of the world.
In the austral winters of 1971 and 1972, the R/V Hero, a research vessel of the National Science Foundation was engaged in oceanographic research along the coast of Argentina (Cummings et al., 1971; Jehl, 1973b). One objective was to obtain data on the distribution, abundance, and ecology of sea birds over the continental shelf. General pat- terns of sea bird distribution in this area have been presented by Murphy (1936), Escalante (1970). and others (references in Cooke and Mills, 1972). Watson et al. (1971) have mapped the distribution of those antarctic and subantarctic species that occur there. Yet. detailed data are scarce and pertain mostly to observations made in spring, summer, or autumn. With the exception of Cooke and Mills' (1972) report on a brief summer transect between Buenos Aires and Tierra del Fuego there seem to be no precise quanti- tative data for shelf waters at any season. Tickell and Woods (1972) discussed sea bird abundance between Montevideo, Uruguay, and the Falkland Islands on the basis of 17 transects in the period November-May 1954-64; however, their transect route was largely beyond the continental shelf and their quantitative data are too simplified for detailed analysis.
This paper deals mainly with quantitative data obtained on three transects of the Argentine coastal shelf: one in June 1971 between the Strait of Magellan and Bahi'a Blanca; the second in July 1971 on the return voyage; and the third in July-August 1972 between Buenos Aires and the Strait of Magellan. The dates of the several transect periods were far enough apart that distributional changes through the austral winter could be determined. The present data with those of Cooke and Mills (1972) also allow a prelimi- nary comparison of summer and winter differences in abundance, distribution, and
SAN DIEGO SOC. NAT. HIST.. TRANS. 17 (16): 217-234. 28 JUNE 1974
218
ecological impact of the sea bird fauna.
The sun'ey area. — The coast of Argentina is bordered by a broad, shallow continental shelf, which extends offshore for about 180 km at the latitude of Mar del Plata, 500 km near Bahia Blanca, and 800 km, to the Falkland Islands, off the Strait of Magellan. Over most of the shelf depths are less than 60 fathoms, and along the transect routes depths over 40 fathoms were uncommon.
The shelf waters are derived from the subantarctic waters of the Falkland (Malvinas) Current, which flows northward along the edge of the continental slope. They can be sep- arated into two zones. South of Golfo San Jorge (ca. 47° S) strong westerly winds prevail for most of the year, forcing surface waters seaward, and causing upwelling. In that area surface waters are cold and rich in dissolved oxygen, nitrates, and phosphates. North of Golfo San Jorge, surface waters are warmer and levels of dissolved nutrients are much lower. Beyond the continental shelf off northern Argentina, the Falkland Current brings subantarctic waters into sharp juxtaposition with the warmer shelf water. Although condi- tions there are similar to those prevailing over the southern shelf, it is useful to recognize a third zone beginning about 30 km landward of the continental slope.
The northern terminus of the Falkland Current varies seasonally. In August- September waters beyond the continental slope retain a subantarctic character to about 36°30' S. There they meet and mix with warmer waters moving northeastward off the continental shelf and with subtropical waters of the southward-flowing Brazil Current. This area of confluence, which is often realized near the mouth of the Rio de la Plata, creates rich feeding conditions for a wide variety of sea birds (Murphy, 1936; Escalante, 1970; Cooke and Mills, 1972). There is a pronounced faunal shift there, with warm water species reaching their southern limits and cold water species their northern limits over the shelf.
Detailed oceanographic information on the region may be obtained in the extensive series of "Pesqueria" reports (Aragno, 1968; Valdez, 1969; Villanueva, 1969-1971). Cooke and Mills have summarized some of these data that pertain to the summer months.
CRUISE TRACKS AND METHODS
In 1971 the Hero departed Punta Arenas, Chile, on 11 June and proceeded northward over the continental shelf of Argentina to Bahi'a Blanca, arriving on 25 June (Fig. 1). In general the transect route lay 16 to 40 km offshore, although we cruised within several km of the beach in Golfo San Jorge and Golfo Nuevo. Observations were made in Golfo San Jose' on 22 and 23 June. We left Bahi'a Blanca on 28 June for Golfo San Jose, remaining inside the gulf until 8 July. After a port call in Puerto Madryn we proceeded southward on 12 July along a route similar to that of the northward transect, except for crossing Golfo San Jorge near its mouth. The cruise terminated in Punta Arenas on 16 July.
In 1972 the Hero left Buenos Aires, Argentina, on 26 July. Between 28 and 30 July we cruised slowly southwestward between 37°07' S and 41°40' S, mostly over deep water beyond the continental shelf but occasionally zigzagging over the edge of the shelf. Late on 30 July we re-entered shelf waters and headed to Puerto Madryn, arriving on 1 August. Late on 3 August we departed for Golfo San Jose, where we spent the period 4 to 19 August. Following a port call in Bahi'a Blanca, we departed for Punta Arenas on 22 August, arriving there on 30 August. The route was similar to that of the southward transect in 1971, except that most of 25 August was spent in Bahi'a Concepcion and 27 August in Bahi'a de los Nodales.
In 1971 I made censuses as often as possible, except when the ship was at anchor. The duration of the observations depended upon weather conditions and ship's activities, and varied from 2 to 7 hours per day. In 1972, with the assistance of Jon P. Winter, it was possible to monitor bird populations almost continously. Most observations were made from a flying bridge 7 m above the waterline, affording good visibility in all directions. All birds were counted, but for ship-following species the maximum numbers were estimated hourly. In 1971, daily counts were totalled, whereas in 1972, for increased precision, they were divided into morning and afternoon components. Surface water temperatures were taken regularly except when sea conditions precluded work on deck. Quantitative data.
219
Figure 1. Cruise track of the R/V Hero along the coast of Argentina during transects reported in this study: 1972 (left), 1971 (right).
precise localities, and sea surface temperatures are given in Tables 1 and 2.
In this paper I consider only those species that regularly occur over the open ocean, or more than about 5 km from shore. Information on Golfo San Jose' is presented else- where (Jehl, RumboU, and Winter, 1973). Specimens obtained in these studies are depos- ited in the Natural History Museum, San Diego.
In the following species accounts I follow the generic classification of Procellariiformes of Alexander et al. (1965). Otherwise, classification and common names largely follow Meyer de Schauensee (1966). The exceptions involve my strong preference for retaining the traditional whalers' names for certain species. In my opinion the use of such prosaic names as Gray Petrel for Pediunker and White-chinned Petrel for Shoemaker has little, if anything, to recommend it.
ANNOTATED LIST OF SPECIES
Rockhopper Penguin (Eudyptes crestatus). — Rockhopper Penguins follow the Falkland Current north to Uruguay in winter (Escalante, 1970). They seem restricted to the cold, deep waters beyond the continental shelf, and may be much commoner off northern Argentina than the literature suggests. Groups of up to 15, mostly adults, were common between 36-40° S in late July 1972; the maximum concentration was 79/hour. Over the continental shelf, however, Rockhoppers were rare or absent. The only sighting in 1971 was of a single bird near 40° S on 15 July. In 1972 a few appeared at the southern edge of Golfo San Jorge, where surface temperatures dropped sharply to 4.4° C, but none
220
were seen in colder waters farther south. In summer Cooke and Mills (1972) recorded only one Rockhopper over the shelf near 52°40'S.
Magellanic Penguin (Spheniscus mugellanicus). — In summer Magellanic Penguins are common in the vicinity of nesting colonies in southern Argentina (i.e., south of 44° S); in winter they largely abandon these areas and move northward as far as Uruguay and southern Brazil. We found them fairly common between Buenos Aires and the Valdes Peninsula, uncommon to rare southward; in all areas their local abundance was markedly reduced by turbid water. All sightings were made in shelf waters, mostly within 30 km of shore in areas where surface temperatures exceeded 9° C. On all three transects we found concentrations 15 km off the Valdes Peninsula; maximum densities were 27/hour. The largest concentration, 300 birds, 150 km east of the peninsula on 31 July 1972, was near the area where Cooke and Mills found large flocks in summer. Penguin flocks were usually accompanied by South American Terns {Sterna hirnndinacea) and Sooty Shearwaters (Piifjinus griseus), which feed on fish that penguins drive to the surface. This penguin- tern-shearwater assemblage is the most conspicuous and characteristic avian grouping over northern shelf waters.
Wandering Albatross (Diomedea exulans), Royal Albatross (D. epomophora) . — Rare over the northern shelf but slightly commoner farther south. In 1971 we saw occasional great albatrosses as far north as the Valdes Peninsula but the only concentration, 20 birds, was in Bahi'a Grande on 15 July. Small numbers near the Valdes Peninsula and in Golfo San Matias in late August 1972 indicate a northward shift of the population later in win- ter. Beyond the continental shelf great albatrosses were fairly common from 36-40° S. They appeared as soon as the ship crossed into deep water and often outnumbered the Black-brows. Their abundance declined immediately as we re-entered the shelf waters and en route to Puerto Madryn none was seen closer to land than 200 km.
On 29 July 1972 we saw over 110 great albatrosses, 3 of which were color banded; 30 were with a large tlock of Black-brows at 39°22' S; 50 more along with other seabirds fed on scraps from a fishing trawler; and another 30 were scattered along the route. Most of the birds in the first group of 30 were photographed; of these, at least 4 were Royals (dark line on tomium visible) and 20 were Wanderers. Sight records suggest a similar species composition in the other groups. No Royals were identified over shelf waters in 1972, although two birds in 1971 were thought to be epomophora (Cabo Danoso, 15 July; Bahi'a Engano, 18 June).
Robertson and Kinsky (1972) showed that large numbers of Royal Albatrosses use the southwestern Atlantic as a major feeding area, particularly in winter. However, their sug- gestion (following Dabbene, m Murphy, 1936) that it is the common species of great albatross there is questionable. The present data indicate that Wanderers greatly out- number Royals throughout the winter, in coastal as well as offshore waters. Robertson and Kinsky (1972) also found that about 55 per cent of the Royals wintering in the south- western Atlantic are three years old or less and about 70 per cent are four or less. Wan- dering Albatrosses of those ages retain considerable brown in their plumage and should be distinguishable in the field (see Tickell, 1968: fig. 12). Yet, only one of over 145 great albatrosses observed in this study was in the brown juvenile plumage of exulans; four were in the adult ''chionoptera' stage of exulans; and the rest were in plumages in which the two species are usually indistinguishable. If my estimates of relative abundance are accu- rate, it would appear that Wanderers wintering off Argentina average several years older than Royals in the same are. This is a potentially important biological difference between these similar species that requires confirmation. Furthermore, since mottled immatures of exulans were fairly common along the coast of Chile in the winter of 1970 (pers. obs.), the average age of Argentine Wanderers may be greater than that of birds wintering off the Pacific coast of South America.
Black-browed Albatross (Diomedea melanophris) . — Common to abundant along the entire coast, except where waters are excessively turbid. In both years it was rather regu- larly distributed over the shelf north to Bahia Blanca, and concentrations were found off the Valdes Peninsula and in Golfo San Jorge, although in 1971 the largest numbers (150/hour) were seen in Bahi'a Grande. No important seasonal or yearly differences in
221
Figure 2. Part of a tlock of 10,000 Black-browed Albatrosses and other sea birds. Coast of Argentina. 39°22'S. 55°22'W, 29 July 1972.
distribution were evident. Tickell and Woods (1972) did not observe seasonal differences in abundance on transects between Montevideo and the Falkland Islands.
The species was also common — and once spectacularly abundant — near the edge of the continental shelf. On the morning of 29 July 1972 an estimated 10,000 were feeding with other sea birds and a large pod of Pilot Whales {Globicephala melaetia) near 39°22' S, 55°22' W at the edge of the shelf (Fig. 2). That afternoon an additional 10.000 were feeding on scraps from a large trawler. Over the entire route it appeared that adults out- numbered immatures by about 5 to 1, although immatures seemed more likely to occur in near-shore waters and mouths of bays. Many birds near Buenos Aires were heavily oiled.
Giant Petrel [Macronectes gigatiteus). — Widespread and remarkably uniformly dis- tributed in shelf and offshore waters through the year, though commoner in winter. Usually three or four followed in our wake. Over 500 were scavenging offal near a fishing ship at 39°40' S on 29 July 1972.
In 1971 approximately 70 per cent of the birds seen were immatures, whereas in 1972 adults slightly outnumbered immatures over the continental shelf. This age distribution suggests a possible influx of adults later in the winter. Beyond the continental shelf immatures composed over 70 per cent of the flocks, and in harbors and waters very close to shore they predominated strongly. Only 3 white-phased birds were encountered, one with a huge flock of sea birds at 39°22' S in 1972, and two well inside Golfo Nuevo in 1971. No birds suspected of being Macronectes halli were among the giant petrels flying near the ship (see Bourne and Warham, 1966, for characters that may allow these similar species to be identified under field conditions).
Southern Fulmar [Fulmtirus glacialoides). — Common to abundant over southern shelf waters in winter, in waters colder than 7° C. In June and July 1971, Southern Fulmars were common to about 49° S, but disappeared abruptly in warmer waters to the
222
north. On the southward transect in August 1972 a few appeared at 44° S, where temper- atures dropped under 7° C, but none was seen again until 47°24' (4.4° C). Fulmars were uncommon but regular beyond the continental shelf at 36-40° S; surface temperatures there were less than 6.7° C. Cooke and Mills did not record this species on their summer transect.
Cape Pigeon {Daption capense). — Cooke and Mills did not observe this species during their cruise. In June 1971 it was widely distributed but uncommon; in July 1971 it was seemingly commoner, especially in the south; and in August 1972 it was common over much of the shelf and in offshore waters. These data suggest a shift northward as the winter progresses. It occurred in greatest abundance beyond the continental shelf on 29 July 1972, where flocks of 4000 and 6000 were in association with albatross fiocks.
Whale-birds or Prions {Pachyptila spp.). — In 1971 scattered prion flocks were seen between San Julian and the Valdes Peninsula, and in Golfo San Jose. The largest concen- tration (up to 150/hr.) occurred off Rio Chico on 15 July. In August 1972 they were uncommon to rare over shelf waters, except inside Golfo San Jose (Jehl et al., 1973). Prions were somewhat commoner offshore, especially near 41°40' S, where we found scattered flocks of 10-15 birds. Although P. desolata and P. belc fieri are said to occur in this general area (Escalante, 1970), the only specimens we obtained were belcheri (cT, 109 g, 37°22' S, 54°24' W; cf, 4r38' S, 56°43" W; ??, Golfo San Jose). In summer Cooke and Mills observed prions only south of 50° S, near presumed breeding grounds.
Pediunker {Procellaria ciriereus). — A single bird made several passes near the ship on 30 July 1972, when we set out a chum slick well offshore. This was our only observation of the species, which appears to avoid shelf waters at all seasons. Not recorded by Cooke and Mills.
Shoemaker (Procellaria aequinoctialis). — In June 1971, Shoemakers were widespread though generally uncommon along the entire coast, whereas a month later they were virtually absent south of 43° S. In August 1972, too, they were uncommon in coastal waters north of 44° S. and much rarer to the south. In both years concentrations occurred in waters adjacent to the Valdes Peninsula.
Beyond the continental shelf Shoemakers replaced Sooty Shearwaters as the dominant, and usually only, species of shearwater, though they appeared to be no commoner there than in coastal waters. The limited data hint that this species may be more abundant in summer than in winter.
Greater Shearwater [Puffmus gravis). — Common to abundant in summer but rare or absent in winter, when the species occurs in the North Atlantic. Our only winter observations were in mid-June 1971: four between 43°40' S and 42°00', and several in Golfo San Jose. These were apparently late stragglers on the northward migration.
Sooty Shearwater (Puf'finus griseus). — In winter Sooties are largely restricted to shelf waters north of 45° S; their distribution seems to be strongly affected by surface temperatures for they are rare in waters cooler than 9° C. On the northward transect in June 1971 none were seen south of 43°40' S (9.5° C), but farther north they were common to abundant, particularly near the Valdes Peninsula (maximum, 375/hr.). On the southward transect in July they seemed rarer. Only scattered individuals were seen between the Valdes Peninsula and Golfo San Jorge and the only bird seen farther south (47°35' S) was sick and emaciated (specimen, weight 563 g).
A similar distribution was observed in August 1972, with concentrations off the Valdes Peninsula and the northeastern corner of Golfo San Matias (maximum 800/hr.), and in the mouths of the larger bays. Although some birds occurred as far south as the Strait of Magellan, they were uncommon south of 45° S. One hundred and fifty km off the Valdes Peninsula we observed 600 with large flocks of South American Terns and Magellanic Penguins. Sooties were virtually absent from waters beyond the continental shelf.
Manx Shearwater {Pujfinus pujfimis). — This northerm hemisphere migrant winters commonly off the northern coast of Argentina (Cooke and Mills, 1972), but leaves the area in the austral winter. Our only sightings were in 1972; one, 50 km S. of the coast of Uruguay, 27 July; and two in Golfo San Matias, 23 August.
223
Wilson's Storm-Petrel (Oceanites occanicus). — In both years Wilson's Storm-Petrels were rare over the continental shelf between the Strait of Magellan and Bahia Blanca, and the only area of local abundance (maximum 23/hr) was off the Valdes Peninsula. Nearly all of our observations were made north of 44° S, where surface temperatures exceeded 9° C. The similar distribution patterns found in all three transects indicate that migration is largely completed by June. These petrels were widespread but still uncommon in colder waters (<6° C) beyond the continental slope, Twenty- tlve, in a small area 225 km SE of Mar del Plata on 29 July 9172, comprised the only significant concentration. Surprisingly, Wilson's Storm-Petrel seems even rarer in shelf waters in summer. Cooke and Mills saw only a single storm-petrel (sp.?) during their transect.
Gray-backed Storm-Petrel (Garrodia nereis). — This species was not observed by Cooke and Mills (1971), and Escalante (1970) does not include it in his compilation. We saw only one bird over shelf waters, 37 km offshore at 48°59' S on 15 June 1971. Beyond the shelf, on 30 July 1972, we saw tlve birds and collected one (cr*, wt. 33 g) near 41°38' S, 56°43' W. They were associated with a tlock of six Wilson's Storm-Petrels. These appear to represent the northernmost records of the species (cf. Watson et al., 1971; Olrog, 1958), which nests on the Falkland Islands.
Megallanic Diving-Petrel (Pclccanoides magellani) . — This was the only species of diving-petrel that could be identified in the shelf waters of southern Argentina, and all observations there are referred to it. In each year it occurred to Golfo San Jorge, which is farther north than the range given by Meyer de Schauensee (1966), though it was regular only south of 49° S and common to abundant only between the mouth of the Rio Chico and the Strait of Magellan. The largest concentration (85/hr.) was found in Bahia Grande on 15 July 1971. Although these diving-petrels seem to prefer waters colder than 7° C, we found no seasonal or yearly differences in distribution even though quite different water temperatures prevailed in the two years. In summer Cooke and Mills saw a few diving-petrels, presumably magellani, near Bahia Grande.
Subantarctic Diving-Petrel (Pelecanoides urinatrix). — This species, which nests on the Falkland Islands, ranges north to Uruguay in winter (Escalante, 1970). Apparently, it follows the Falkland Current, for we saw scattered diving-petrels, all presumably urinatrix, well offshore in late July 1972. Our first records were made on the night of 27 July, when 7 flew aboard; all had fed on small crustaceans 8 to 10 mm long. Other sightings were made between 35-42° S, mostly near the edge of the continental shelf; one bird was as close as 160 km from shore. Weights: 2?: 148, 160 g; 4(^: 120, 144, 145, 145 g.
Great Skua (Catharacta skua). — Skuas are rare off Argentina in summer (Cooke and Mills, 1972) and in winter. Our few sightings in 1971 were made within a mile or so of land, generally in the vicinity of bays and harbors, and the only concentration included several flocks on the beach at San Julian on 14 June. Only 9 skuas were seen in 1972: five off Mar del Plata on 27 July, one well offshore on 30 July, and three in near-shore waters between the Valdes Peninsula and Golfo San Jorge. All were referable to C. s. chilensis except for one near Mar del Plata which was probably C. s. antarctica. In each year several skuas wintered in Golfo San Jose; some of these did not appear to be chilensis and may have been antarctica.
Parasitic Jaeger (Stercorarius parasiticus). — One record, a dark-phased bird near Golfo Nuevo on 18 June 1971.
Kelp Gull {Larus dominicanus). — In winter Kelp Gulls disperse widely along the Argentine coast. Apparently their post-breeding movements are largely completed by June, because we noted no important distributional differences in the three transects. Except for local concentrations in bays and near centers of human habitations, this gull was uncommon within 30 km of the coast, and was virtually absent farther offshore. None were seen beyond the continental shelf. Well over 90 per cent of the birds were adults. Cooke and Mills encountered the species rarely, and only near land. Weights: 6</, 850- 1130 (952) g; 8$, 430 (starved), 680-1040 (865) g.
Brown-hooded Gull (Larus maculipennis). — Not seen at sea, except for three in mid-Golfo San Matias in 1971. Fairly common in large harbors north to Buenos Aires.
224
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226
South American Tern (Sterna hintndinacea). — After the nesting season South American Terns leave southern Argentina and migrate north to Brazil. They were rare or absent south of 40° S, and uncommon south of Golfo San Jorge. Farther north they were common to abundant, particularly near the mouth of bays and near the Valdes Peninsula, where large tlocks were present each year (maximum 375/hr.). We saw no terns beyond the continental shelf, although on 31 July 1972 we observed scattered terns up to 190 km offshore, and 140 km offshore 1500 were feeding with Sooty Shearwaters and Magellanic Penguins. All seemed to be hiniiiditiacea, but other species could have been overlooked. Most sighting were made within 30 km of shore.
ZONATION, CONCENTRATIONS
Each of the three oceanographic zones in the survey area contains a distinct faunal assemblage. Sphetiiscus magellanicus, Pujftnus griseus, Oceanites oceanicus. and Sterna hinindinacea were largely restricted to the continental shelf north of Golfo San Jorge; surface temperatures there were greater than 7° C. Farther south, particularly south of 49° S, sea temperatures were lower and those species were rare or absent. Fulmanis glacialoides. Eudyptes crestatus, Pelecanoides magellani appeared and Diomedea exulans/ epomophora and Pachyptila spp. became commoner. In cool waters beyond the continental shelf off northern Argentina the avifauna was similar to that of the southern shelf. Immediately as we passed beyond the shelf Puffinus griseus, Spheniscus magellanicus, and Sterna hinindinacea dropped out and the following species appeared or occurred in greatly increased numbers: Diomedea exulans/ epomophora, Fulmanis glacialoides, Eudyptes crestatus, Pachyptila spp., Garrodia nereis, Procellaria cinereus, and Pelecanoides urinatrix. Note that the diving-petrel of deep waters (urinatrix) is not that of the southern shelf (magellani).
Precise patterns of distribution within these zones are strongly affected by local conditions, especially turbidity. Waters in many near-shore areas (e.g., the mouth of the Rio de la Plata nearly to Punta del Este; much of the north shore of Golfo San Matias and northward within 15 km of shore to Bahia Blanca; the mouth of the estuary near San Julian) are heavily laden with sediment. This reduces underwater visibility and precludes the presence of divers such as penguins; it also reduces feeding opportunities for plungers such as terns and some shearwaters. Even scavengers are scarce, presumably because increased turbidity also reduces the size of tlsh populations.
Concentrations of sea birds were found in few localities, and indeed the general sparseness of sea birds over shelf waters was impressive. Concentrations seemed to occur mainly in areas of upwelling or strong tidal currents, where vertical mixing could enrich surface waters. For example, in each year flocks of Magellanic Penguins, Sooty Shearwaters, and South American Terns were at the mouth of Golfo Nuevo and Golfo San Jose as well as 8-15 km of the northeastern corner of the Valdes Peninsula. On 23 August 1972 large numbers of sea birds were distributed across the mouth of Golfo San Matias, but greatest abundances were realized east of Punta Rasa and near the tip of the Valdes Peninsula. Strong tidal currents prevail in all of these areas. The only other significant concentration over shelf waters consisted largely of great albatrosses. Black-browed Albatrosses, Magellanic Diving-Petrels, Southern Fulmars, and prions in Bahia Grande on 15 July 1971. Surface temperatures there were anamalously cold (4.5° C), suggesting a strong, local upwelling.
Farther offshore, large flocks of terns, penguins, and shearwaters were feeding 150 km east of the Valdes Peninsula on 31 July 1972. Cooke and Mills (1972) also found sea bird concentrations there and pointed out that the area is rich in dissolved nutrients.
The largest concentrations were at the edge of the continental shelf. On the morning of 29 July at 39°22' S, 55°22' W, we estimated 10.000 Black-browed Albatrosses, 30 Royal/Wandering Albatrosses, 4,000 Cape Pigeons, 300 Giant Petrels, 2 Shoemakers, 2 Southern Fulmars, and 1 Sooty Shearwater, all in association with a pod of Pilot Whales. As we passed through the flock we were accompanied by ranks of 50 to 100 Black-brows sailing by in formation, and this sight was repeated in all directions over an area of
227
perhaps eight km^. Many of the birds, particularly the great albatrosses, were feeding on white wormlike masses approximately 20 cm long, and on dead reddish fish (presumably Sehustes or Hclicolcnus, Scorpaenidae). That afternoon we found an even larger concentration, also at the edge of the shelf, near 39°40' S, 55°35' W. There, 10,000- 12,000 Black-browed Albatrosses, 50 Royal/Wandering Albatrosses, 6,000 Cape Pigeons, and 500 Giant Petrels were feeding on offal from a large trawler. In each area sonar tracings revealed the presence of large schools of fish.
SEASONAL DIFFERENCES
Census data indicate few pronounced differences in the distribution and abundance of most species over the Argentine coastal shelf in winter. Apparently wintering popula- tions are established by mid-June and remain largely stable through August. To obtain a more representative picture of average winter conditions, I pooled the data from all three transects. This procedure reduces bias from inadequate sampling on individual transects and minimizes differences caused by minor variations in routes. In Table 3 the combined data are compared with those gathered by Cooke and Mills in a rapid transect between Buenos Aires and Tierra del Fuego in summer. For convenience the data are grouped by 2° increments of latitude. The data from each season are not so complete as to inspire any great confidence as to their general applicability; however, they are the only available quantitative data and can be used to make preliminary comparisons of summer and winter patterns.
Differences between the summer and winter surveys are largely interpretable in terms of the breeding biology of particular species. For example, the high density of Speniscus magi'lhmicus south of 44° S in summer is attributable to concentrations in the vicinity of nesting colonies; winter densities are lower because the species disperses widely over the northern shelf waters. A similar pattern of increased density near known or presumed southern nesting grounds in summer followed by northward dispersal in winter is shown by Pachyptila ssp. (presumably P. belcheri from the Falkland Islands), Eudyptes crestatus. and Pelecanoides magellani.
Albatrosses and Giant Petrels occupy the shelf waters year-round, with few differences in distribution or abundance. These species have long deferred maturity. If populations of great albatrosses in the area consist largely of pre-breeding-age individuals, as seems to be the case for D. eponiophora, the lack of large seasonal differences would not be unexpected. However, the higher density of Macronectcs in winter may reflect a post-nesting influx of adults. This is suggested by the apparent increase in adults in August 1972 as compared with earlier censuses. Large concentrations of Diomedeu mclunophris between 42-48° S in summer suggest locally rich feeding conditions that do not persist into the winter months.
Though not as pronounced, deferred maturity is also characteristic of smaller Pro- cellariiformes (Ashmole, 1971: Table 2), and one would expect some non-breeders of most species to occur in the area throughout the year. The absence of fulmarine petrels [Fulmarus glucicdoides. Daption capensis) in summer is probably attributable to their breeding biology: young birds tend to search for nesting sites at colonies several years in advance of active breeding (G. E. Watson, pers, comm.).
Proci'Uariii acquinoctialis is resident in the southern hemisphere, nesting in the austral summer (Murphy, 1936: 644;. Its apparent predominance in summer seems unusual and may be due to concentrations of non-breeders near 44° S; the situation may be similar to that shown by D. mclunophris. Pujfinus gravis was virtually absent in winter, having migrated to the northern hemisphere; its abundance far from any known nesting grounds in summer presumably indicates a large population of non-breeding individuals (see also Watson, 1971; Tickell and Woods, 1972). Most Puffinus griseus winter in the northern hemisphere, but large numbers occur over the Argentine shelf all year. The limited data do not suggest any important differences in abundance between wintering and summering populations in the area, but there is an obvious shift northward in winter. However, much greater abundances are expected during periods of migration.
228
TABLE 3. A comparison of winter (W) and summer (S) seabird densities over the continental shelf of Argen- tina. Winter data are pooled from three transects (see text); summer data are from one transect (Cooke and Mills, 1972). Abundance indicated is number of birds per hour of observation. Species seen on fewer than five days are omitted from the winter sample.
Species
40-42 42-44
Latitude °S 44-46 46-48 48-50
50-52 52-54
Eudyptes crestatus
Spheniscus magellanicus
Diomedea exulans/ epomophora
Diomedea melanophris
Macro nectes giganteus
Fulmarus glacialoides
W S
w s
w s
w s
w s
w s
5.4
0.3
3.0
2.8
0.3
0.2
0.5
0.5
7.5
0.4
41
0.5
|
5.4 |
1.7 |
0.5 |
0.5 |
0.8 |
— |
|
— |
19.5 |
10.0 |
3.0 |
0.8 |
0.5 |
|
0.6 |
0.1 |
0.1 |
6.0 |
0.4 |
|
|
0.5 |
0.7 |
1.7 |
0.3 |
0.8 |
— |
|
5.3 |
2.9 |
10.8 |
9.7 |
66 |
2.4 |
|
9.2 |
32 |
13.2 |
5.5 |
0.8 |
3.5 |
|
3.1 |
3.6 |
2.8 |
6.8 |
8.0 |
3.1 |
|
2.7 |
2.2 |
3.1 |
2.1 |
1.6 |
1.0 |
6.0
Daption capensis Pachyptila spp. Procellaria aequinoctialis Puff inus gravis Puffinus griseus Puffinus puffinus
Oceanites oceanicus (incl. petrel sp.)
Pelecanoides magellani (and Pelecanoides sp.)
Catharacta skua
Stercorarius parasiticus (and Stercorarius sp.)
Larus dominicanus
Sterna hirundinacea
Hours of observation
W S
W S
W
s
w s
w s
w s
w s
w s
w s
w s
w s
w s
w s
2.0
2.5
2.1
2.6
1.4
1.6
1.3 13.2
5.4
120
1.1
0.5
2.2
|
2.5 |
0.8 |
2.1 |
8.0 |
78 |
4.4 |
|
— |
— |
— |
— |
16.3 |
19.0 |
|
7.5 |
0.8 |
2.1 |
0.7 |
6.8 |
5.6 |
|
15.1 |
60 |
4.8 |
1.5 |
0.8 |
0.5 |
|
36 |
284 |
67 |
8.3 |
0.8 |
0.5 |
|
36 |
18.0 |
1.7 |
2.4 |
|
3.6 |
|
5.6 |
51 |
0.8 |
— |
— |
1.0 |
2.5 0.5
0.1 0.4
0.6 4.3
24.8 39.6
0.5
0.4
0.2
9.2
0.2
0.9
4.4
0.2
1.9
0.9
0.7 3.5 40
6.6 3.9 2.4
4.8
0.2
0.8 27.6
9.3
31.0 6.2
16.5 17.0 13.5
2.7 2.3 3.2
0.8
0.4
0.4
2.5 1.2
11.8 2.5
0.4 0.5
2.0
5.0 2.0
229
Oceanites oceanicus and Catharacta skua were uncommon at both seasons, though more widespread and northerly in winter. Post-breeding northward dispersal in Lams dominicatius and Sterna hinindinacea is largely responsible for their predominance in the winter censuses, although the virtual absence of L. domitiicanus in summer is partly attributable to the fact that Cooke and Mills' route was farther offshore than the normal range of this gull.
Two migrants from the northern hemisphere, Pujfitius pufjhius and Stercorarius parasiticus, occurred almost exclusively in their non-breeding season, the austral summer; at the latitudes under consideration the shearwater is very uncommon.
In all three winter transects the transition between the northern and southern shelf avifaunas occurred near 47° S. Cooke and Mills suggested that the transition zone was nearer 50°S in summer, but it seems to occur near Golfo San Jorge area in that season as well (Table 3, Fig. 5).
ECOLOGICAL CONSIDERATIONS
Despite their limitations, the quantitative data are useful in suggesting questions for future research. For example, do latitudinal or seasonal distributional patterns of sea birds suggest corresponding differences in the productivity of shelf waters. Neither the winter nor the summer data show any consistent relationship between latitude and sea bird abundance (Fig. 3), although in both seasons the highest concentrations were recorded in the northern half of the census area. Seasonal differences in abundance also seem minor, as the summer and winter curves correspond fairly closely over most of the range. (North of 40° S the winter data were largely gathered beyond the continental shelf.) Biomass is a more useful index to productivity, for it indicates the total mass of
300
200
3 O
X
100
50
36
Winter
Summer
38 40 42 44 46
OS Latitude
48
50
52
Figure 3. Sea bird abundance along the coast of Argentina, plotted to nearest 0°30' of latitude. Winter data are pooled from three transects; summer data are from Cooke and Mills (1972).
230
organisms that is being maintained in an area. To obtain this statistic, the density of each species in Table 3 was multipHed by its average weight (Appendix) and the resuhs were summed, giving grams/hours/2° increment of latitude. The data hint at increased biomass to the north (Fig. 4), but they are strongly biased by inadequate sampling, particularly at the higher latitudes. The winter peak at 50-52° S is especially suspect, being based on only 2-1/2 hours of observations on a single day. In summary, present data on sea bird abundance and biomass do not indicate marked seasonal or latitudinal differences in the productivity of the Argentine coastal waters. This conclusion is tentative and requires additional study.
A more interesting question is how seasonal and latitudinal differences in species composition may affect patterns of resource utilization. Table 4 presents a simplified ecological classification of sea birds modified after Ashmole (1971), which should be consulted for details. In this table, I have grouped the avifauna into nine categories based on size of bird, major feeding behaviors, and food preferences. The Shoemaker is separated from the other shearwaters partly because of its greater size and different feeding behavior, but mainly because it is resident in the southern hemisphere and therefore its ecological impact is expected to be more constant. Since total biomass at any latitude is variable (Fig. 4) and is strongly affected by census errors, the data have been converted to a percentage basis for each category. When these data are presented graphically (Fig. 5) the marked change in the ecological composition of the sea bird community at 46-48° S is emphasized.
In summer, north of this area, virtually the entire biomass is made up of large species that obtain their food from the upper meter of the sea, mainly by surface seizing or pursuit plunging (albatrosses, large and small shearwaters). The remainder consists largely of divers (penguins) that feed on t'lsh. Groups that feed at least in part by filtering small organisms (fulmarine petrels, prions and storm-petrels) are absent. South of 46-48° S large surface feeders compose only 50-60 per cent of the biomass, and there is a sharp increase in the biomass of divers and filter feeders. The high percentage of gulls and skuas at 48-50° S is based on a concentration of Parasitic Jaegers. Jaegers typically derive much of their food by piracy; however, since likely prey species were rare or absent they may have been feeding by surface seizing or scavenging.
40 2 42 4 44 6 46 8 48 50
°S latitude
Winter ■ Summer '
502
52 4
Figure 4. Seasonal relationship between biomass (grams/hour) and latitude along the coast of Argentina, plotted by 2° increments of latitude. Winter data are pooled from three transects, summer data are from Cooke and Mills (1972).
231
TABLE 4. A simplified ecological classification of seabirds (modified from Ashmole, 1971]
Group
Species
Weight
Major Food
Foraging Behavior
|
A. |
Albatrosses and giant petrels |
Diomedea exulans D. epomophora D. melanophris Macronectes giganteus |
Larger than 3000g |
Fish, carrion, cephalopods |
Surface seizing, scavenging |
|
B. |
Fulmarine petrels |
Fulmarus glacialoides Caption capensis |
350-7 OOg |
Crustaceans, cephalopods, carrion |
Surface seizing, filtering, scavenging |
|
C. |
Gulls and skuas |
Larus dominicanus Catharacta skua Stercorarius parasiticus |
500-1 500g |
Varied |
Scavenging, surface seizing, piracy |
|
D. |
Prions and storm- petrels |
Pachyptila spp. Oceanites oceanicus Garrodia nereis |
30-1 30g |
Small fish, plankton |
Filtering, pattering |
|
E. |
Large shearwaters |
Procellaria aequinoctialis |
1250g |
Cephalopods, fish, crustaceans |
Surface seizing, pursuit plunging |
|
F. |
Smaller shearwaters |
Puffinus gravis Puffinus griseus Puffinus puffinus |
400-750g |
Fish, cephalopods crustaceans |
Surface seizing, pursuit plunging |
|
G. |
Terns |
Sterna hirundinacea |
200g |
Small fish |
Plunging |
|
H. |
Penguins |
Spheniscus magellanicus Eudyptes crestatus |
2500-4900g |
Fish, cephalopods, crustaceans |
Pursuit diving |
|
1. |
Diving-petrels |
Pelecanoides magellani Pelecanoides urinatrix |
150-160g |
Crustaceans, small fish |
Pursuit diving |
In winter the transition zone persists at 46-48° S, but biomass relationships are more complex. The proportion of surface feeders increases from about 75 per cent in the north to 90 per cent in the south. In the north this is divided among albatrosses, large and small shearwaters, and gulls; the remainder consists of diver (penguins) and plungers (terns). In the south albatrosses alone make up approximately 75 per cent of the biomass, the remainder being contributed by smaller surface feeders and filter feeders; the percentage of divers is much reduced, and plungers are absent.
Through the year the biomass contributed by some ecological groups remains fairly constant. Surface feeders dominate the shelf waters all year, and piratical feeders make up a fairly consistent though small proportion of the biomass. It is interesting, however, that major seasonal shifts in distribution shown by many species are not accompanied by a compensatory movement into the vacated area by taxa that utilize the similar foods. For example, penguins vacate the southern shelf in winter, and fulmarine petrels, prions, and diving-petrels shift northward. The biomass they contributed to southern waters is not replaced by other divers, small scavengers, or filter feeders but by large surface feeders. Also, terns congregate over the northern shelf in winter, an area that contained no plungers in summer. These shifts may indicate an increase in the spectrum of available food in winter. More likely, however, a wide variety of foods is present all year but cannot be exploited in summer because this area is too distant from nesting colonies.
Marine bird populations beyond the continental shelf. — The marine avifauna beyond the continental shelf differs importantly both in species composition and in relative abundance of species from that nearer shore. The major differences noted in winter have been discussed (p. 226). Tickell and Woods (1972) reported several species on transects between Montevideo, Uruguay, and the Falkland Islands from late spring to late autumn that we did not find over the shelf in winter. These included Phoebetria palpebrata, Pterodroma macroptera. Pt. lessoni, Pt. incerta. Pt. mollis, Halobaena caenilea. Fregetta tropica, Fregetta grallaria, Stercorarius pomarinus, and S.
232
<
g
CO
402
468 480
°S Latitude
44 6
48 0
50-2
Figure 5. Biomass relationships ot'seabirds by feeding types, along the coast of Argentina in winter (upper) and summer (lower). Groupings comprising less than 1 per cent of the biomass for any period arc not plotted. A. Albatrosses and giant petrels. B. Fulmarine petrels. C. Gulls and skuas. D. Prions and storm-petrels. E. Large shear\\aters. F. Smaller shearwaters. G. Terns. H. Penguins. 1. Diving-petrels.
lon^^icaiidus. Several other species e.g., (Procc/laria cincrcus. PuJIimis gravis, Garrodia nereis) seemed to be tar commoner in deep waters than near shore. Almost certainly, sea bird density, latitudinal patterns of abundance and distribution, and ecological patterns of resource utilization also differ significantly between these areas, but the only semi- quantitative data (Tickell and Woods, 1972) are insufficient to permit even preliminary comparison and analysis.
233
MORTALITY
In 1972 vve found the desiccated remains of Magellanic Penguins every 30 m or so along the beaches of Golfo San Jose (Jehl et al., 1973); extensive mortality was also noted at Punta Norte and elsewhere on the Valdes Peninsula. Most of the birds had been dead for a long time, and although there was no evidence that the mortality had been caused by a single event, the majority of the carcasses were oiled. At sea it was not uncommon to observe oiled albatrosses. Giant Petrels, and Cape Pigeons. I made no quantitative esti- mates, but the incidence of oiling was greatest off northern Argentina, particularly in the vicinity of the Rio de la Plata. This heavily-trafficked area is close to one of the most important feeding grounds for sea birds in the South Atlantic (Murphy, 1936; Robertson and Kinsky, 1962; Cooke and Mills, 1972). In many miles of beachcombing in Golfo San Jose, 1 found the remains of few pelagic birds other than penguins, and none that were oiled. Flying birds are less likely than penguins to amass lethal doses of oil at one sitting, but even small amounts can break down the insulation of the feather coat and lead to death far from the area of contamination. Further, the pelts of Procellariiformes are less durable than the tough hides of penguins, and their bodies seem more likely to be devoured by Giant Petrels and other scavengers before they can drift ashore. I suspect that the incidence of sea bird mortality from oil pollution, even in the remote reaches of the South Atlantic, is more insidious and pervasive than the present documentary evidence indicates (see also Jehl, 1975).
ACKNOWLEDGMENTS
The research was made possible from a grant (NSF-GV-32739) from the National Science Foundation. The assistance and cooperation of Master Frank Liberty, Master P. J. Lenie. and the crew of the R/V Hero is sincerely appreciated. 1 am indebted to Jon P. Winter, W. C. Cummings. J. F. Fish, and P. O. Thompson for assistance in the field, to Carl L. Hubbs for ichthyological information, and to George E. Watson for comment- ing on a draft of the manuscript.
LITERATURE CITED
Alexander, W. B., et al.
1%5. The families and genera of the petrels and their names. Ibis 107: 401-405. Aragno, F. J.
1%8. Datos y resultados preliminares de las campafias pesqueria: "Pesqucria 1. II, III." Mar del Plata, Argentina, Publicaciones del projecto de dcsarrollo pesquero (Series Informes Technicos) Nos. 10/1, 10 II. 10/111. Ashmole, N. P.
1971. Sea bird ecology and the marine environment, p. 223-285. //;. D. S. Farner and J. R. King (cds.). Avian Biology. Vol. 1. Academic Press, N. Y, and London.
Bourne, W. R. P.. and J. Warham
l%b. Geographical variation in the Giant Petrels of the genus Macroncctcs. Ardea 54: 45-67. Cooke. F.. and E. L. Mills
1972. Summer distribution of pelagic birds off the coast of Argentina. Ibis 144: 245-251. Cummings. W. C, J. R. Fish, P. O. Thompson, and J. R. Jehl, Jr.
1971. Bioacoustics of marine mammals off Argentina. R. V. Hero, Cruise 71-3. Antarctic J. U. S. b(b): 2hf)-2b8. Escalante, R.
1970. Aves marinas del Rio de la Plata. Montevideo, Barreiro y Ramos, S. A. Jehl, J. R., Jr.
1973a. The distribution of marine birds in Chilean waters in winter. Auk 90: 114-135.
1973b. Winter populations of marine birds along the coast of Argentina. Antarctic J. U. S., 7(2): 32-33.
1975. Mortality of Magellanic Penguins in Argentina. Auk 92, in press. Jehl. J. R.. Jr., M. A. E. Rumboll. and J. P. Winter
1973. Winter bird populations in Golfo San Jose. Argentina. Bull. Brit. Ornith. CI. 93: 56-63. King, W. B.
1970. The trade wind /one oceanographv piKit studv. Part 7: Observations of sea birds March 1964 to June 1965. LI. S. Fish Wildl. Serv. Spec. Sci. Rept. Fish. No. 586. Lack, D.
1968. Ecological adaptations for breeding in birds. London, Methuen and Co., Ltd, Meyer de Schauensee, R.
1966. The species of birds of South America. Narberth. Pennsylvania. Livingston Publ. Co.
234
Murphy, R- C.
1936. Oceanic birds of South America, 2 vols. New York, Amer. Mus. Nat. Hist. Olrog, C. C. «.
1958. Observaciones sobre la avifauna antarctica y de alta mar desde el Rio de la Plata hasta 60° de latitud sur. Acta Zool. Lilloana, 15: 19-33. Robertson. C. J. R., and F. C. Kinsky
1972. The dispersal movements of the Royal Albatross (Diomedea epom'ophora). Notornis, 19: 289-301. Serventy, D. L., V. Serventy, and J. Warham
1971. The handbook of Australian Sea-birds. Sydney, A. H. and A. W. Reed. Tickell, W. L. N.
1968. The biology of the great albatrosses, Diomedea exulans and Diomedea epomophora. p. 1-55. In, O. L. Austin, Jr. (ed.). Antarctic bird studies. Antarctic Res. Ser. 12. 262 p. Washington, D.C., American Geophysical Union.
Tickell, W. L. N., and R. W. Woods
1972. Ornithological observations at sea in the South Atlantic Ocean, 1954-64. Brit. Antarct. Surv. Bull. 31: 63-84.
Valdes, A. J.
1969. Datos y resultados de las campafias pesqueria: "Pesqueria V." Mar del Plata, Argentina, Publicaci- ones del projecto de desarrollo pesquero (Serie Informes Technicos), No. 10/V.
Villanueva, S. D. (ed.)
1969-71. Datos y resultados de las campafias pesqueria: "Pesqueria VI, VII, VIll, IX, X, XI." Mar del Plata, Argentina. Publicaciones del projecto de desarrollo pesquero (Serie Informes Technicos; Nos. 10/VI, 10/VII, 10/VIII, 10/IX, 10/X, lO/XI. Watson, G. E.
1971. Molting Greater Shearwaters (Pufftnus gravis) off Tierra del Fuego. Auk 88: 440-442. Watson, G. E., et al.
1971. Birds of the Antarctic and Subantarctic. Antarctic Map Folio Ser. Folio 14, New York, Amer. Geogr. Soc.
San Diego Natural History Museum, P.O. Box 1390, San Diego, California, 92112.
APPENDIX I Weights of seabirds'
Eudyptes crestatus, 25(X) (L). Spheniscus magelhnicus. 4900 (L). Diomedea exulans/ epomophora. 85(X) (L, SSW, SD). Diomedea melanophris. 3600 (SD). Macronectes giganteus, 30(X) (SSW. SD). Fulmants glacialoides. 700 (J). Daption capensis. 350 (J). Pac/iyplila spp., 130 (J). Procellaria aequinoctialis. 1250 (SD). Pujfinus griseus. 750 (J). Pujfinus gravis, 650 (E). Pujfinus pujfinus, 400 (L). Oceanites oceanicus, 30 (L, J). Peleca- noides mugelUini. 160 (J). Pelccunoidcs urinatrix. 150 (SD, this paper). Catharacta skua. 1400 (SD). Stercorar- ius parasiticus. 500 (L). Lams dominicanus, 910 (SD). Sterna hirundinacea. 200 (SD).
References: L = Lack, 1968, appendix 17. J=Jehl, 1973a. SSW = Serventy, Serventy. and Warham, 1971. SD = specimens in San Diego Natural History Museum. E = estimate.
I
i
MUS. C?OMP. ZOOL- LIBRARY
HARVARD UNIVERSITY,
MEXICAN SPECIES OF THE GENUS HETERANDRIA, SUBGENUS PSEUDOXIPHOPHORUS (PISCES: POECILIIDAE)
ROBERT RUSH MILLER
TRANSACTIONS
OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
VOL. 17, NO. 17
28 JUNE 1974
i
J
MEXICAN SPECIES OF THE GENUS HETERANDRIA. SUBGENUS PSEUDOXIPHOPHORUS (PISCES: POECILIIDAE)
ROBERT RUSH MILLER
ABSTRACT. — The subgenus Fscucld.xiphophorus is currently regarded as monotypic. with a single wide- spread species, Hctcnuulria hiimiciihitu. inhabiting the Atlantic slope of Middle America. Actually, the taxon includes two sharply distinct species in Mexico, the more primitive being H. jonesi; other species of Fsciuloxiphoplionis occur in Guatemala. The basis for recognizing subgenera of Hcterandria is presented as well as a detailed comparison between H. himaculata and H. jonesi. including illustrations of gonopodia. gonopodial suspensoria, and the whole fish. Hetcruudrui jonesi, which occurs at elevations up to 2,385 meters, is close to the ancestral stock of the genus.
RESUMEN. — El subgenero Pseudoxiphophoms. de acuerdo a la literatura corriente. es considerado como monotipico. con una sola especie de amplia distribucion, Hetenindriu himaculata. que habita la vertiente Atlantica de Mexico y America Central. Como se muestra aqui, en Mexico hay dos especies claramente distintas, la mas primitiva siendo //. jonesi: otras especies de Pseudoxiphophoms existen en Guatemala. La base para reconocer subgeneros de Heterandria se presenta asi como una comparacion detallada entre H. hinuiculata y H. jonesi. incluyendo ilustraciones de gonopodios, suspensores de gonopodio, y ademas de el pez completo. Heterandria jonesi. que occure a alturas hasta 2.385 metros, es cercano a el tronco ancestral de el genero.
Until the recent general review of the Poeciliidae by Rosen and Bailey (1963), Heter- andria and Pseudoxiphophonts were regarded as monotypic genera represented, respec- tively, by H. formosa Agassiz in Florida and adjacent coastal lowlands, and by P. bi- maculatus (Heckel) from northeastern Mexico southward and eastward into Nicaragua. Among ichthyologists publishing on Pseudoxiphophoms during this century, only Regan (1904-1913) consistently maintained that this subgenus comprises two fully distinct species, although Hubbs (1924-1936) divided P. bimaculatus into four subspecies, includ- ing the one that is here restored to full specific status. Rosen and Bailey (1963: 131), commenting on Hubbs' action, indicated that the characters distinguishing these forms "are apparently clinal and grade imperceptibly from one race to another." In attempting to distinguish forms oi Pseudoxiphophoms, overemphasis has been placed on the dorsal- ray number which varies widely in the two species of this group in Mexico. As usual in poeciliids, the detailed architecture of the gonopodium proves to have far more important systematic value, although the size and position of the dorsal fin is also highly useful. Color pattern helps to distinguish the Mexican species (Pseudoxiphophoms) but it is too variable for complete reliance.
Regan was correct in concluding that P. Jonesi (restricted to east-central Mexico) and P. bimaculatus are distinct species, even though the male of jonesi was unknown to him. As here shown for the first time, the gonopodium of Heterandria Jonesi is consistently and sharply distinct from that of H. bimacukita. Although these species have overlapping ranges they are rarely taken together, as in central Veracruz (see below). My paper on the zoogeography of Middle American freshwater fishes (Miller, 1966) did not include the extralimital H. Jonesi, but recognition of more than one species of Pseudoxiphophoms in Mexico was implied in the range statement for Heterandria bimacukita, since the sub- genus Pseudoxiphophoms ranges northward into southeastern Tamaulipas.
This paper presents a detailed comparison between H. Jonesi and H. bimacukita in Mexico, illustrates their distinctive gonopodia and suspensoria as well as the general form and appearance of each species, and discusses variation in coloration, body proportions, and meristic characters. The distribution of the two species is also treated and support is presented for the view that H. Jonesi is closest to the common ancestor of the genus.
SAN DIEGO SOC. NAT. HIST.. TRANS 17(17): 235-250, 28 JUNE 1974
236
MATERIALS AND METHODS
Specimens examined came from the following museum collections: BMNH, British Museum (Natural History), P, Instituto Politecnico Nacional (Mexico), UMMZ, Univer- sity of Michigan Museum of Zoology, USNM, United States National Museum. I am grateful to P.H. Greenwood for making a syntype oX MoUietiisia jonesii available, to Jose Alvarez for the loan of topotypes of that species, to William M. McLane and Brandon McNair for information regarding the sympatric occurrence of H. bimaculata and H. jonesi, to Royal D. Suttkus for the loan and exchange of specimens, to the staff of the National Museum of Natural History (USNM) for facilities and working space, and to the John Simon Guggenheim Memorial Foundation for support as a Guggenheim Fellow while preparing this manuscript. Appreciation is also extended to Martha B. Lackey, former staff artist of the Museum of Zoology, for the accompanying illustrations, except Figure 4, drawn by Patricia J. Wynne, current staff artist. I am grateful to Mexican officials for permission to collect fishes in their country.
|
Table |
1. |
Distingu |
sh |
ng |
characters of the |
subgenera |
of Heterandria. |
|
Character |
Heterandria |
Pseudoxiph ophorus |
Gonopodium (Fig. 2):
Serrae on posterior margin of ray 4p
Segments beyond distalmost serrae of ray 4p
Tip of ray 5a
Distal part of ray 3
7-9
5 or fewer
Extends beyond tip of ray 4p
Widely separated from ray 4
9-18
5 or more
Extends to or falls short of of tip of ray 4p
Closely adjoining ray 4
Gonopodial suspensorium (Fig. 3):
Ligastyle
Tip of gonapophysis I
Reduced to an oval remnant below 10th vertebra
Extends ventrally about 1/3 way from vertebral column to insertion of pelvic fin
An elongate bone lying below 1 1th vertebra
Extends ventrally more than 1/3 to 1/2 way from vertebral column to insertion of pelvic fin
Reproductive biology: Superfetation
Egg size at fertilization,
2 in mm
o
Brood interval Size
Strongly developed 0.37-0.40
1
Averaging 5-6 days (small broods)
Minute; largest mature male ca. 14 mm S.L.
Absent as far as known 2.08-2.56
35-40 days (large broods)
Moderate; smallest mature male (jonesi) ca. 22 mm S.L.
Dorsal fin of female
About equal in size to anal, its origin behind anal origin, over 16th or 17th vertebra
Much larger than anal, its origin usually farther forward (behind in one species), over 12th to 15th vertebra
Dorsal rays Vertebral number
6-8
Sexually dimorphic; males 32-34, females 30-33 (Table 4)
9-18
No sexual dimorphism; total variation, 30-34
As many as 6 stages of developing embryos in a single ovary (Turner, 1937). ^From Scrimshaw, 1946; based on H. formosa and H. bimaculata only. ^At height of reproductive season (Turner, 1937). "^Over 16th in one form in Alta Verapaz, Guatemala (D.E. Rosen, pers. comm.)
237
Counts and measurements were made as prescribed by Hubbs and Lagler (1958: 19-26). Measurements are expressed as permillages of the standard length; they were taken with dial calipers reading to the nearest tenth of a millimeter. One ratio (length of depressed dorsal into predorsal length) was stepped off with a pair of dividers and esti- mated to the nearest tenth. A second ratio (base of dorsal tin into predorsal length) was measured with calipers, converted into permillages, and mathematically calculated — a more accurate and objective means of obtaining the required figures. The vertebral count includes the hypural plate as the terminal vertebra; the second vertebra is the first rib-bearing one in all cyprinodontoids.
CHARACTERS OF THE TWO SUBGENERA
When only two species were assigned to Heterandria, the need for subgeneric recogni- tion was minimal. Now that Pseudoxiphophorus is polytypic (probably containing three or more species — Miller, 1966, and Rosen and Bailey, MS), it is helpful to employ the subgenus when discussing the Middle American forms. Consequently I have drawn up a comparison (Table 1) which provides a biological as well as a structural basis for recog- nizing two subgenera of Heterandria: some may feel the differences are sufficient for generic recognition. Characters that indicate a close relationship between Pseudoxipho- phorus and Heterandria involve the morphology of the reproductive system and the breed- ing behavior as well as the osteology of the skull (as pointed out by Rosen and Bailey, 1963: 128-129). Another interesting common feature discovered in the present study is the marked sexual dimorphism in the length of the snout: H. Jonesi—43 males, 78-96; 47 females, 92-1 II. H. himacuUita—30 males, 82-100; 30 females, 94-111. (Figures are permillage of standard length; see Table 3.) H. formosa — 10 males, 58-75; 10 females, 76-89. Another interesting aspect of the comparison is the sexual dimorphism in vertebral number in subgenus Heterandria only: males, 32 (8), 2)2) (26), 34 (3); females, 30 (1), 31 (13), 32 (18), 22 (1) — Table 4. The tiny egg of the subgenus Heterandria is correlated with the high degree of dependence on the mother for nourishment by the developing embryo. Such virtual elimination of yolk is paralleled in certain species of Poeciliopsis (e.g., Poeciliopsis elongata [Giinther] and P. prolijica Miller— see Schultz and Thibault, MS), in which superfetation is also strongly developed. Presumably superfetation is not developed in subgenus Pseudoxiphophorus (checked only in H. himaculata and H. jonesi).
THE MEXICAN SPECIES
Heterandria jonesi (Gunther) (Figs. 1-3)
Mollienisia joncsii. — Gunther, 1874: 371 (original description, based on females only; Lago Alcuhuaca, Mexico = Lago de Aljojuca — see Alvarez, 1950). Gamhusia Joncsii. — Regan. 1907: 260 (name; comparisons). Regan, 1906-08: 94, 97-98, pi. 12, fig. 8 (key;
description; synonymy; female syntype figured; distribution). Pscudoxiphophnnis jonesii. — Regan, 1913: 993 (synonymy; description; range).
Pseudoxiphophorus himuculatus jom-sii. — Hubbs, 1924: 17-18 (characters; synonymy). Alvarez, 1950:
88-91 (redescription of topotypes; correction of type locality to Lago de Aljojuca, 15 km NE of Ciudad
Cerdan, Puebla; comparison with sample from Tepeaca, Puebla, in Ri'o Balsas basin).
Pseudoxiphophorus bimaculatus (misidentification). — Woolman, 1894: 55-56 (description; Rio Blanco at
Orizaba). Jordan and Evermann, 1896: 678 (description, based on Orizaba specimens). Meek, 1904: 127
(in part; Orizaba records only).
Heterandria himaculata (misidentification). — Rosen and Bailey, 1963: 131 (in part; references io jonesi and pauciradiatus). Pseudoxiphophorus reticuhitus (misidentification). — Jordan and Evermann, 1896: 678, footnote (description of
specimens from Ri'o Blanco at Orizaba, where only H. Jonesi occurs). Pseudoxiphophorus pauciradiatus. — Regan, 1904: 256 (original description, based on 8 of Woolman's speci- mens from Orizaba). Regan, 1905: 362-363 (validity of species; comparison with bimaculatus). Regan. 1907: 260 (listed as synonym oi Mollienisia Jonesii).
Diagnosis. — A species of the subgenus Pseudoxiphophorus (Table 1) distinguished from H. himaculata as follows (see also Table 5): Terminal segment of ray 4a of gono-
r //
^^^,
***>■
y ■"*^-
5^^^ i 1 1 j^r 1% II H\' Vv* An r/«
K'XCv^^:^^^f^.
Xl<ii0im>xi
*?" T -r * iiiiiiiS"'^
£12^
pjrSS-
'J6c^:k- -
Figure 1. Top io botloiii: Uctcrumhiu joiicsi. adult male, M mm, RaiKho .Sierra de Agiia, Ori/aba Valley (L'MMZ 1838')4); Hclcnuidria jouvsi. adult temale, 43.5 mm. t'rt)ni same collection (topotypes of P. painircnlialtis Regan); Hcicnindria himaciilata. adult male, 35,5 mm. Nacimiento de Cosolapa (UMMZ 183902); Hclcrandria himuciilata. adult female, 50 mm, from same collection.
239
podium short (not longer than 2-3 subdistal segments and often barely exceeding penuhi- mate one), sHghtly reciir\ed, not reaching tip of enclosing membrane; anterior margin of subdistal segments of ray 4a smooth; ray 4p forming part of curved tip of gonopod (Fig. 2). Base of dorsal tin enters predorsal length 1.6 to 2.4 times in males, and 2.0 to 2.9 times in females; depressed dorsal fin enters same distance 1.2 to 1.6 (rarely 1.1) times in males, and 1.4 to 2.0 times in females. Origin of dorsal fin more posterior (Table 3). Basicaudal spot generally smaller, lower, and more anterior, lying mostly on caudal peduncle.
Type locality. — This species was described from Lago de Aljojuca, a crater lake or axalapazco (Tamayo, 1964: 113) in the endorheic part of the high Puebla Plateau (Llanos de El Salado), 15 km northeast of Ciudad Cerdan, Puebla, and west of the great volcano Pico de Orizaba (5,750 m) at an elevation of 2,385 m (Alvarez, 1950, 1972). Apparently it is the only fish native to this lake, although three other similar lakes to the north each
Table 2. Variation in number of dorsal fin rays in two species of Heterandria from Mexico.
Cat. no. and/or authority and locality^
Number of dorsal rays
10 11
12 13 14 15
16
17
No. Avg.
H. jonesi
P 203, Alvarez, 1950 (topotypes)^,
Lago de Aljojuca, Puebla P 184, Tepeaca, Puebla (Balsas basin) 183986, Acosac, Puebla (Balsas basin) 186675, Tehuacan, Puebla (Papaloapan
basin) 183894, Hubbs, 1924, 1926, Orizaba
Valley 162143, Ri'o Atoyac, Veracruz"^ 183896, Rfo Atoyac, Veracruz 124304, Rfo Necaxa, Puebla
(Tecolutia basin) 193493, 42 km WSW Poza Rica,
Veracruz (Cazones basin) 124330, 162141, Palitla.S.L.
Potosf (Panuco basin) 183887, Jaumave, Tamaulipas
(Tamesf basin)
|
70 |
34 |
|
5 |
13 |
|
17 |
13 |
22
7 - -
|
38 |
149 |
14 |
|
48 |
43 |
1 |
|
96 |
29 |
— |
- - - 24 20
12
19 54
8 24
104 11.33
20 11.75
30 11.43
30 12.20
211 12.00
96 11.42
125 11.23
47 12.55
19 12.32
76 12.79
35 13.86
H. bimaculata
Hubbs, 1924, 1926, Jico and Jalapa,
Veracruz (Chachalacas basin) USNM 31023,45489, Mirador,
Veracruz (Chachalacas basin) 162144, Rfo Atoyac, Veracruz'* 181309, Hubbs, 1924, 1926, Cordoba,
Veracruz (subtopotypes) Regan, 1905, Rfo Tonto, Veracruz
(Papaloapan basin) 183902, Cosolapa, Oaxaca
(Papaloapan basin) 124234, 4 km E El Hule, Veracruz
(Papaloapan basin) Regan, 1905, in Hubbs, 1924, Sto.
Domingo Petapa, Oaxaca (Coatza-
coalcos basin) 178533, Rfo Sarabia, Oaxaca
(Coatzacoalcos basin)
2 30 11 2
6 23 4
8 26 4
1 7 30 13
- 5 7
3 12 32 13 3 21 28 1
1 3 1
12 23 16
45 13.29
33 13.94
38 13.89
51 14.08
15 14.87
- 60 13.92
53 13.51
1 6 15.33
51 15.08
Catalog numbers are those of UMMZ unless otherwise stated. 2|n 28 loaned from this series I counted 1 1 (22), 12 (6). Also included is a count of 12 on a syntype, BMNH
1873.1.13.1 (illustrated by Regan, 1906-08: PI. 12, Fig. 8). -^Sympatric with bimaculata (162144). ^Sympatric v\i\th jonesi (162143).
240
Figure 2. Gonopodia of: A. Heterundria jonesi; B. Hetenuulrici bimiiculata; C. Heterandria fonnosa.
contain an atherinid of the genus Poblana {-Chirostoma: see Bolland and Barbour, MS). The tlsh was named for its discoverer, T.M. Rymer Jones.
Variation. — The gonopodium (Figs. 2, 3) provides the major criterion for distinguish- ing//. Jonesi from its relatives. It is therefore important to know how much it varies. The three characteristics given in the diagnosis include the variation known for the populations examined. Other features follow. Ray 3 terminates near the proximal end of segments 3 to 6 of ray 4a. There is sharp transition between the several elongate proximal segments of ray 4a and the short subterminal segments. There is always a rather abrupt change in height and size between the most proximal serra-bearing segment of ray 4p and the next succeeding segments of this ray. These shorter segments, which precede the last one of ray 4a, vary from 2 to 5. Ray 4p has from 12 to 18 strong, retrorse serrae. Ray 5a ends about 2 to 4 segments from the tip of ray 4a.
Ten measurements were made on males and females of four populations of H. Jonesi (Table 3) representing: (1) the type locality of the species (Aljojuca), at 2,385 m; (2) the type locality off. pauciradiatus (Orizaba), at 1,240 m; a locality (Palitla) in the southern part of the Rio Panuco basin, at about 120 m; and the northernmost known population (Jaumave), in the headwaters of the Rio Guayalejo, at about 330 m. These data show that: (1) Aljojuca and Orizaba specimens have the shortest dorsal-fm base, Jaumave the longest, with Palitla intermediate; (2) Jaumave females have the longest anal tin, Orizaba and Aljojuca the shortest, with Palitla somewhat intermediate; (3) the caudal tin is longest at Jaumave, generally shortest at Orizaba and Aljojuca, and again somewhat intermediate at Palitla, although the measurements do not overlap those at Jaumave; (4) body depth varies greatly, in part because of the reproductive condition of the female, as at Aljojuca (see below); (5) head length shows little or no sexual dimorphism at Aljojuca, Orizaba, or in the Rio Atoyac at Atoyac (10 males, 269-283, ave. 273, 10 females, 260-280, ave. 269), but is dimorphic at Palitla and Jaumave (and might be found to be so in populations at lower elevations between Atoyac and Palitla); (6) snout length is sharply dimorphic between the sexes at all four localities, as are predorsal length and distance between dorsal origin and base of caudal tin; but that (7) the distance from anal origin to caudal base is neither sexually dimorphic nor significantly different in the four samples.
The number of dorsal-fin rays is highest at Jaumave, among the lowest at Aljojuca. and intermediate at Palitla (Table 2).
Vertebral number is rather consistently 32, varying from 31 to 33, in Puebla and adjoining parts of Veracruz, but shows a decrease toward the north (southwest of Poza
241
Figure 3. Gonopodial suspensoria ot: A. HelcnuiJna Jonrsi; B. Hetcrandria himciciilatu; C. Hi'tcnindriu for- iiiosa. (From same specimens illustrated in Fig. 2.)
Rica, in the Rio Cazones basin), especially at Jaumave, where the mode is 31 and the range 30 to 32 (Table 4).
Color pattern is rather consistent for the populations from the Puebla Plateau (Alojojuca, Tepeaca, Acosac), the Orizaba Valley, and the Rio Atoyac. They are moder- ately to strongly barred, with 3 to 1 1 rather narrow and usually short, vertical bars con- fined to the midside from just behind the base of the pectoral fin to just before the basi- caudal spot. Generally, the larger fish have the most bars. These vary from 5 to 9 in the
242
Table 3. Proportional measurements of Heterandria jonesi and H. bimaculata (in permillage of standard length).
|
Heterandria jonesi |
/y. bimaculata |
|||||
|
Aljojuca |
Orizaba |
Palitia |
Jaumave |
Cordoba |
Cosolapa |
|
|
P 203 |
183894 |
162141 |
183887 |
108614-^ 181309 |
183902 |
|
|
Standard length. |
||||||
|
Range (mean) No. |
1 |
|||||
|
IVlales |
23.0-36.1 |
23.6-36.1 |
24.4-37.1 |
22.8-27.1 |
30.1-48.4 |
25.5-51.9 |
|
(27.2) 7 |
(30.9) 15 |
(30.1) 14 |
(25.4) 7 |
(38.9) 15 |
(39.2) 15 |
|
|
Females |
31.1-41.6 |
29.9-55.5 |
30.1-55.0 |
26.0-47.1 |
32.7-68.4 |
43.1-76.2 |
|
(38.2) 4 |
(41.5) 15 |
(38.9) 13 |
(36.7) 15 |
(50.0) 15 |
(55.9) 15 |
|
|
Body depth |
||||||
|
Males |
267-290 |
264-295 |
264-297 |
266-306 |
253-290 |
249-288 |
|
(282) |
(280) |
(281) |
(293) |
(270) |
(267) |
|
|
Females |
255-283 |
274-333 |
271-296 |
296-323 |
240-281 |
248-281 |
|
(267) |
(299) |
(282) |
(310) |
(261) |
(265) |
|
|
Predorsal length |
||||||
|
Males |
516-534 |
500-538 |
489-532 |
498-522 |
453-494 |
452-486 |
|
(525) |
(516) |
(519) |
(510) |
(470) |
(470) |
|
|
Females |
575-593 |
568-597 |
553-573 |
561-589 |
496-536 |
516-546 |
|
(587) |
(582) |
(563) |
(576) |
(520) |
(528) |
|
|
D. Origin to C. base |
||||||
|
Males |
490-518 |
495-520 |
492-531 |
515-533 |
540-583 |
539-571 |
|
(500) |
(507) |
(515) |
(523) |
(563) |
(554) |
|
|
Females |
421-430 |
427-461 |
456-483 |
450-476 |
477-514 |
479-508 |
|
(426) |
(445) |
(466) |
(462) |
(500) |
(493) |
|
|
A. origin to C. base |
||||||
|
Females |
437-453 |
413-452 |
431-448 |
422-450 |
431-470 |
438-460 |
|
(445) |
(437) |
(439) |
(437) |
(455) |
(449) |
|
|
Head length |
||||||
|
Males |
270-287 |
263-280 |
263-296 |
266-276 |
266-287 |
250-275 |
|
(279) |
(269) |
(278) |
(270) |
(276) |
(261) |
|
|
Females |
270-286 |
263-293 |
276-308 |
272-300 |
252-306 |
252-282 |
|
(279) |
(277) |
(295) |
(284) |
(281) |
(267) |
|
|
Snout length |
||||||
|
Males |
78-89 |
78-87 |
86-96 |
79-82 |
85-100 |
82-96 |
|
(83) |
(82) |
(92) |
(81) |
(92) |
(89) |
|
|
Females |
93-97 |
92-105 |
99-111 |
92-103 |
89-108 |
94-107 |
|
(95) |
(98) |
(105) |
(98) |
(102) |
(101) |
|
|
C. peduncle depth |
||||||
|
Males |
163-177 |
158-176 |
148-186 |
166-193 |
165-186 |
157-190 |
|
(170) |
(168) |
(169) |
(184) |
(178) |
(178) |
|
|
Females |
147-151 |
144-161 |
160-171 |
172-183 |
155-178 |
153-168 |
|
(150) |
(151) |
(164) |
(176) |
(162) |
(161) |
|
|
D., basal length |
||||||
|
Males |
235-255 |
225-256 |
268-299 |
302-325 |
326-369 |
329-358 |
|
(244) |
(245) |
(284) |
(309) |
(348) |
(342) |
|
|
Females |
205-210 |
202-226 |
242-267 |
264-290 |
284-310 |
273-315 |
|
(207) |
(213) |
(253) |
(274) |
(300) |
(302) |
|
|
A., depressed length |
||||||
|
Females |
190-203 |
182-211 |
203-225 |
234-252 |
193-239 |
199-243 |
|
(196) |
(196) |
(213) |
(244) |
(212) |
(220) |
|
|
C, length middle rays |
||||||
|
Males |
238-258 |
221-245 |
237-275 |
279-289 |
227-260 |
231-275 |
|
(248) |
(232) |
(258) |
(283) |
(239) |
(248) |
|
|
Females |
220-227 |
206 231 |
225-256 |
257-284 |
203-239 |
201-230 |
|
(223) |
(215) |
(246) |
(271) |
(218) |
(216) |
material examined from Aljojuca, although large females (such as the syntype figured by Regan, 1906-08: pi. 12, fig. 8, 65 mm S.L., examined by me) may show no trace of bars. At Acosac, adults of both sexes have from 3 to 8 bars, although a 63-mm female lacks
243
them. In the Orizaba Valley, 45 fish (30 males, 15 females) have from 4 to 10 bars. Vertical bars are most strongly developed in the two samples from Rio Atoyac, wherein all tish (including young only 11 mm long) are barred, and the number of bars varies in 53 adults from 6 to 11, usually 8 to 10. In the Rio Cazones drainage (42 km WSW of Poza Rica), the bars on males are weakly developed (1-7 in 14) and are apparently lacking in females and juveniles. At Palitla, bars are also weakly developed in males (from none to 7) and none is evident in females or juveniles. The extreme variation is attained at Jaumave, where none of the fish collected show vertical bars. The basicaudal spot, also quite uniform from the Puebla Plateau to Rio Atoyac, is rather small, generally oval, and lies mostly on the base of the caudal peduncle not far above the body axis (Fig. 1). In the Rio Cazones collection, the spot is larger, higher, and almost as much of it lies on the caudal fin as on the peduncle, thus more closely approaching the basicaudal spot typical of H. himaculata. At Palitla, the spot is more like that at Rio Atoyac except that it lies higher above the body axis. At Jaumave, the basicaudal spot is similar to that at Palitla but tends to become obsolete in large females.
Biology. — As suggested above, body depth in females is strongly influenced by pregnancy. In the four mature females measured from Aljojuca (Table 3), collected 21 May 1949, there were large mature eggs but no embryos. Permillage values for body depth are from 255 to 283 (avg. 267), whereas in 43 females from the three other localities (with mean standard lengths not greatly different from those of the females from Aljojuca) these values are from 271 to 333 (avg. 282, 299, 310). Clearly the reproductive season is much shorter at Aljojuca (2,385 m) than it is at the lower elevations. For example, in the 10 largest and fattest females, collected 18 March 1968 from Acosac (UMMZ 183986, ca. 1,830 m), one had advanced embryos, one had early embryos, and eight were packed with large eggs — demonstrating that at this lower elevation the reproductive season was well under way, even though the tlsh were taken earlier in the year. At still lower elevations production probably occurs over a long time span as suggested by the two collections made during the latter half of December from Atoyac (UMMZ 162143) and Palitla (UMMZ 162141), each of which contains individuals as small as 11 mm.
It is a general observation for poeciliids (but not for all viviparous cyprinodontoids — e.g., goodeids, Fitzsimons, 1972: 730) that males have determinate growth and attain maturity at widely different sizes. This is abundantly supported for H. jonesi by the fol- lowing data giving the frequencies for each standard length measurement (rounded to nearest whole number) followed by number of specimens and mean value: Orizaba Valley (UMMZ 183894), 24 (7), 25 (16). 26 (9), 27 (9), 28 (11), 29 (8), 30 (2), 31 (4), 32 (3), 34 (6), 35 (3), 36 (2), in 80, range 23.6-36.1 mm, mean 28.1 mm; Rio Atoyac at Atoyac (UMMZ 183896). 27 (1), 29 (I), 30 (1), 31 (2), 32 (1), 35 (1), 36 (2), 37 (7), 38 (3), 39 (2), 41 (1), 42 (1). 45 (1), 46 (1), 25, 37.5 (range 27.5-45.7 mm). The Orizaba collection is from a spring-fed, roadside ditch, whereas the Atoyac collection is from a large river.
At only one locality and at only one time were H. jonesi and H. himaculata taken together and then the circumstances were unusual although the data on number of dorsal rays suggest that sympatry may be normal in this area. The collection was made by W. McLane and B. Schultz on 23 December 1940 in the Rio Atoyac (then in flood), 6.5 km north of Hacienda Potrero Viejo (E of Cordoba and N of Hwy 150) and contains 96 speci- mens of //. /o//('5/ (1 1-53 mm, UMMZ 162143), including one transforming male, and 38 of//, bimaculata (10-40 mm, UMMZ 162144), including one mature male. The dorsal rays (Table 2) show an overlap only at 13 rays; the 8 specimens of H. bimaculata with that number are discussed under Variation in the account of that species.
Range. — The northern limit of this species (Fig. 4) is the Rio Guayalejo of south- eastern Tamaulipas, the major tributary of the Rio Tamesi, where it must be scarce. Darnell (1962) failed to take Heterandria in the 66 collections (totaling over 1 1,000 fishes) made during 1950-53 in the Tamesi basin, and that only two collections are known from that drainage: 2 specimens from near the bridge just west of Nuevo Morelos, Tamaulipas, Rosen and Gordon, 18 January 1957 (specimens lost), and 94 from Jaumave, discussed herein. The species is probably widespread in suitable habitats throughout the Rio Panuco basin (up to elevations near 2,000 m — e.g., Tula, Hidalgo) southward to the Rio
244
Table 4. Number of vertebrae in three species of Heterandria from Mexico and Florida.
Species, cat. no. , locality
Number of vertebrae
30
31
32
33
34
No.
Avg.
H. jonesi (Mexico)
P 203, L. Aljojuca, Puebia (topotypes)
P 184, Tepeaca, Puebia (Balsas basin)
183986, Acosac, Puebia (Balsas basin)
187718, Orizaba Valley, Veracruz
183896, Rfo Atoyac, Atoyac, Veracruz
193493, WSW Poza Rica, Veracruz (Cazones basin)
162141, Palitla.S.L. Potosf (Panuco basin)
183887, Jaumave, Tamaulipas (Tamesf basin)
H. bimaculata (Mexico)
1
USNM 31023, 45489, Mirador, Veracruz
(Chachalacas basin) 108614, 181309, Cordoba, Veracruz (subtopotypes) 183902, Cosolapa, Oaxaca (Papaloapan basin) 124234, near El Hule, Veracruz (Papaloapan basin) 178533, Ri'o Sarabia (Coatzacoalcos basin)
H. formosa (Florida)
USNM 133265, Crows Bluff, Deland, males
females USNM 210703, Monroe Station, Tamiami Trail,
males
females
|
— |
12 |
2 |
|
2 |
8 |
— |
|
— |
13 |
— |
|
— |
19 |
6 |
|
4 |
24 |
1 |
|
11 |
6 |
1 |
|
4 |
22 |
— |
|
24 |
1 |
— |
|
1 |
13 |
— |
|
- |
13 |
17 |
|
- |
12 |
7 |
|
8 |
8 |
— |
|
3 |
20 |
1 |
|
2 |
12 |
|
|
7 |
9 |
— |
|
_ |
6 |
14 |
|
6 |
9 |
1 |
|
14 |
32.14 |
|
10 |
31.80 |
|
13 |
32.00 |
|
25 |
32.24 |
|
29 |
31.90 |
|
18 |
31.44 |
|
26 |
31.85 |
|
30 |
30.87 |
|
14 |
31.93 |
|
30 |
32.73 |
|
20 |
32.45 |
|
16 |
31.50 |
|
24 |
31.92 |
|
15 |
32.93 |
|
17 |
31.47 |
|
22 |
32.82 |
|
16 |
31.69 |
I
All catalogue numbers are UMMZ, except as noted. Localities under H. jonesi are arranged from high to low elevations (Aljojuca to Atoyac) and from south to north (Poza Rica to Jaumave); under H. bimaculata, they are arranged from north to south.
Nautla. The species reappears in the Rio Atoyac, southwest of Veracruz (City), and is the only Heterandria of the Orizaba Valley and the streams, irrigation ditches, and crater lakes (Aljojuca only) of the Puebia Plateau, where it occurs as high as 2,385 m. In this elevated region it lives in tributaries of the Rio Balsas and Rio Papaloapan as well as in waters without exit to the sea. Its distribution south of the latitude of Tehuacan (1,649 m) is unknown, but it has not been found in the lowlands of the Papaloapan basin or any- where in the Rio Coatzacoalcos system, the next major drainage to the south.
Zoogeography. — The occurrence oi Heterandria jonesi \n a high-elevation crater lake! (Aljojuca) in the endorheic, semidesert basin (area ca. 8,000 km^) occupied by the Llanos de Puebia or San Juan (Tamayo, 1964: 113, Fig. 4) calls for explanation. The remnant native fish fauna (Chirostoma, "Poblana", and Heterandria) in this area indicates that the interior basin they now occupy was connected with at least three different major drainages during late Cenozoic time. Barbour (1973) has presented convincing biological] evidence to tie the area in with the Rio Lerma basin via the Valle de Mexico. The occur- rence of the cyprinid "Aztecula vittata (Girard)" in Pleistocene lake deposits and anj adjacent Recent tributary of the Balsas basin just south of the city of Puebia (Miller and Uyeno, MS) demonstrates a former connection between the Valle de Mexico, Llanos de, San Juan, and the Rio Balsas drainage. Finally, the occurrence of the otherwise exclu- sively Atlantic (in Mexico) subgenus Pseudoxiphophoms in both Lago de Aljojuca and in Rio Balsas tributaries proclaims a former connection between the Llanos de San Juan, the] Atlantic slope, and the Balsas system.
Why docs not Heterandria jonesi also occur in the three other fish-inhabited crater j lakes and in Laguna de El Carmen (the large marsh-like, shallow lake just west of the crater lakes)? Probably because those lakes contain species of atherinids that either prey! on the newborn young of the poeciliid or outcompete Heterandria in other ways. Lago de Aljojuca contains only Heterandria which elsewhere in this plateau region occurs only in
245
spring-ted ditches and ponds tliat contain no other tlshes.
Alvarez (1972) has presented the following hypothesis to explain the distribution of the tlshes of the Llanos. Prior to the Pleistocene this plateau region contained an enor- mous shallow lake that was connected to the Valle de Mexico by way of Apizaco and Apani (Barbour, 1973: Fig. 5). The crater lakes in question were formed much later by volcanic explosion, and their cavities were tilled with water because they all lay below the highest level of the Plio-Pleistocene lake. Because of their different altitudes, the crater lakes were isolated from each other at varying times as the level of the hypothetical lake fell below 2.440 meters.
Lago de Aljojuca is the highest of these tlsh-supporting crater lakes and some partic- ular aspect of the history of its colonization, as yet undetermined, must account for the fact that it alone contains Hetcnnidria. Very likely other species of tlshes became extinct in the area following virtual desiccation of the original lake.
Specimens examined (All in Mexico). — Hidalgo: M74-48. in UMMZ, ditch near Tula; Puebla: BMNH 1873.1.13.1 (syntvpe), Lago de Aljojuca; P 184 (10), Tepeaca; P 203 (20 topotypes), Lago de Aljojuca; UMMZ 124304 (47), Ki'o Necaxa; UMMZ 183986 (50). trib. Rio Balsas at Acosac; UMMZ 186675 (57). trib. Rio Papa- loapan, Teluiacan; UMMZ 193493 (19), trib. Rio San Marcos. 42 km WSW of Poza Rica. San Luis Potosi: UMMZ 124330 (48). 162141 (45). Palitla; Tamaulipas: UMMZ 183887 (94), Jaumave. Veracruz: UMMZ 162143 (96), Rfo Atovac, 6.5 km N Potrero Viejo; UMMZ 183894 (500). Orizaba Valley; UMMZ 183896 (869). Rio Atoyac at Atoyac; UMMZ 187718 (47b), Orizaba Valley.
Heterundria bimaciilata (Meckel) (Figs. 1-3)
Xiphoplionis himuculatus. — Meckel. 1848: 297-299, pi. 9, figs. 1-2 (original description; a clear brook ot the
Orizaba Mountains, Mexico).
Poecilioiile.s himaculutus. — Steindachner, 1863: 176 (original description; Teapa, Tabasco, Mexico — see
Rosen and Bailey, 1963).
Pseudoxiphophonts himaculutus. — Garnian. 1895: 81-82. pi. 3. fig. 6, pi. 8, fig. 9 (in part; synonymy; description). Meek, 1902: 98 (brief description; maximum adult size; notes on eggs, embryos, time of birth). Meek. 1904: 127-128 (in part; synonymy, excluding P. pauciradiatus Regan; description; range). Regan, 1904: 256 (comparison with P. pauciradiatus; P. reticulatus Troschel in synonymy). Regan, 1913: 993-994, fig. 170C (synonymy; description; gonopodium figured). Scrimshaw, 1946 (size of ova and ovisac). Rosen and Gordon, 1953: 26, Fig. 32C (gonopodium). Rosen and Mendelson. 1960: fig. 4M (hypothetical correlation between sensory canals of head and feeding habits). Rosen and Tucker. 1961: fig. 2 (secondary sex characters and sexual behavior).
Heierandria himaculata. — Rosen and Bailey. 1963: 131. figs. 49B, 51 D, 55B (in part; synonymy, excluding references to jonesi and pauciradiatus; range; skeleton and gonopodial suspensorium of male figured). Miller. 1966:790 (range).
Gambusia himaculata. — Regan. 1906-08: 98, pi. 14, fig. 4 (synonymy; description; range, excluding Orizaba).
Gamhusia (Pseudoxiphophorus) himaculata. — Regan, 1907: 260 (listed in comparison with G. annectens).
Pseudoxi/tho/Jtiorus himaculatus himaculatus. — Hubbs, 1924: 18 (synonymy; distribution; dorsal-ray counts). Pseudoxiphophorus himaculatus taeniatus. — Regan. 1905: 363 (original description; San Domingo de Guzman.
Oaxaca. Mexico; this locality, now called Petapa. is on a tributary of the Rio Coatzacoalcos SW of Mati'as
Romero). Pseudoxiphophorus himaculatus peninsulae. — Hubbs. 1936: 230-232, pi. 8, fig. 1 (original description; vicinity
or Progreso. Yucatan. Mexico). Pseudoxiphophorus reticulatus. — Troschel in von Muller, 1865: 638-639 (original description; Mexico).
Diagnosis. — A species of the subgenus Pseudoxiphophorus (Table 1) distinguished from H. Jonesi as follows (see also Table 5): Terminal segment of ray 4a of gonopodium greatly elongate (as long as 4-8 subdistal segments), its tip strongly hooked forward (J- shaped), reaching tip of enclosing membrance; anterior margin of 4 to 6 subdistal seg- ments of ray 4a with keel-like prominences; ray 4p not entering into curved tip of gonopod (Fig. 2). Base of dorsal tin enters predorsal length 1.2 to 1.5 times in males, and 1.6 to 1.9 times in females. Origin of dorsal tin more anterior (Table 3). Basicaudal spot gen- erally larger, higher, and more posterior, lying mostly on caudal tin.
Type Locality. — Confusion has resulted from the common misinterpretation of Meckel's type locality as "Orizaba". In the same paper in which H. himaculata is described, Meckel (1848) also described Xiphophoms helleri and Poeciliopsis gracilis (see
246
♦
Kigurc 4. Distribution ot two species o\ Hctvnindriu in Mexico. For //. hinuiculata (which ranges eastward and southward into Nicaragua) only the records from the Rfo Coat/.acoalcos basin northward are included. Stations are Uom UMMZ records and Meek's (1404: 128) localities (except Sanborn, not found).
Table 5. Comparison between two species of Heterandria inhabiting Mexico.
247
Character
H. jonesi'
H. bimaculata^
Gonopodium (Fig. 2):
Terminal segment of ray 4a
Anterior margin of subdistal segments of ray 4a
Ray 4p
Ray 5a
Gonopodial suspensorium (Fig. 3)
Dorsal origin to caudal base
Predorsal length Base of dorsal fin
Predorsal length
Depressed dorsal-fin length
Basicaudal spot (Fig. 1)
Cross-hatching on sides
Short, slightly curved forward, not reaching tip of enclosing mem- brane; not longer than 2-3 sub- distal segments, often only exceeding penultimate one
Evenly smooth on all
Extending far beyond tip of ray 3 to form part of curved tip of gonopod
Distal part curves evenly toward tip of gonopod; ray 4p is only slightly elevated in this region
Angle of gonactinosts about 45° from vertical. Ligastyle as long as or longer than basal stem of gonapophysis III
Shorter. In permillage of S.L., males 490-533; females 421-483 (Table 3)
Males 1.6-2.4; females 2.0-2.9
Greatly elongate, tip strongly hooked forward (J-shaped), extending to end of enclosing membrane; as long as 4-8 sub- distal segments
With keel-like prominences on 4-6 segments
Extending just beyond tip of ray 3, not entering into curved tip of gonopod
Distal part descends abruptly to ray 4p which is strongly elevated in this region
Angle of gonactinosts about 33° from vertical. Ligastyle shorter than basal stem of gonapophysis III
Longer. In permillage of S.L., males 539-575; females 479-508 (Table 3)
Males 1.2-1.5; females 1.6-1.9
Males 1.1-1.6^; females 1.4-2.0 Males 0.9-1.1 ; females 1.2-1.4
Generally smaller, its position lower and more anterior (weakest in females from Jaumave)
Well developed and generally extending ventrally around caudal peduncle
Generally larger, its position usually higher and more posterior
Well developed above body axis but fading ventrally; none on venter of caudal peduncle
Ratios and proportions based on specimens from 5 populations (including topotypes of M. jonesil and P.
pauciradiatus) as follows: UMMZ 162141 (Palitia), 183887 (Jaumave), 183894 (Orizaba Valley), 183896
(Atoyac), and P 203 (Aljojuca). o Ratios and proportions based on specimens from 2 populations (3 collections, including subtopotypes of
X. bimaculatus) as follows; UMMZ 108614 and 181309 (Cordoba), and 183902 (Cosolapa). o This ratio was determined mathematically by dividing the measurement of the base of the dorsal fin into
that of the predorsal length for each fish.
The ratio of 1.1 \r\ H. jonesi occurred in only 1 male from Jaumave; otherwise the range was 1 .2-1 .6.
Rosen and Bailey, 1963: 131-133) and stated that all three species live together "in einem klaren Bache des Gebirges Orizaba". Although X. helleri inhabits streams of the Orizaba Valley, neither H. hinuiculata nor F. gracilis live there (the only other known fish is H. Jonesi). Therefore, apparently none of Meckel's species came from any tributary of or stream in the trough-like Orizaba Valley, which lies at an elevation of about 1,240 m. Menzel and Darnell (1973: 232), in discussing the type locality of Poccilia mexicana Steindachner, also said to be from Orizaba, concluded that the types came from a much lower elevation in either the Ri'o Jamapa or Ri'o Blanco drainages. Most likely X. helleri and H. himaculaiu (if not P. gracilis) came from the vicinity of Cordoba at an elevation of about 870 m. Woolman (1894: 65) described the rapids and barrier falls in the Rio Blanco, the drainage system of the Orizaba Valley, which prevent the ascent of fishes into
248
this valley from lower elevations to the east of Orizaba.
Variation. — The salient characters distinctive of the gonopodium of this species have been given in the Diagnosis and also appear in Table 5. Additional traits follow. Ray 3 extends to the base of the penultimate segment or to that of the terminal one (the J- shaped hook) of ray 4a. Distal to the elevated tlange or keel of ray 3 are from 6 to 9 small segments. Ray 4a bears from 2 to 4 squarish segments between the terminal one and the last keeled segment, and from 6 to 9 segments distal to the terminal serra on ray 4p. There are 6 to 12 segments distal to the last serra of ray 4p, and this ray bears 10 to 14 strong, retrorse serrae. Ray 5a ends several segments of ray 4a short of the base of the J-shaped hook.
Ten measurements (Table 3) were made on 30 males and 30 females sampled from two places in Veracruz and Oaxaca — Cordoba (approximate type locality of the species) and Cosolapa. approximately 50 airline km SE of Cordoba. These data show very close agreement except in head length, which is longer at Cosolapa. Sexual dimorphism is strongly marked in dorsal origin (as shown by predorsal length, and dorsal origin to caudal base) and basal length of dorsal tin; it is less striking in caudal peduncle depth and length of middle caudal rays.
The number of dorsal tin rays, lowest in the highlands (Jico-Jalapa) near the northern limit of the range, appears to show an increase southward and toward lower elevations. The extreme range for this species is from 11 to 18 (11 in one specimen from Honduras, UMMZ 173305, and 18 in three from Belize, formerly British Honduras — specimens taken by David W. Greentleld at Sta. G70-139).
Vertebral number shows modes of 32 or 2)2> in samples from tlve populations in Mexico (Table 4).
Color pattern is generally more consistent in bimaculata than in Joiiesi. Cross- hatching is well developed on the upper and mid-sides but begins to pale ventrally and fades out entirely over the ventral surface of the caudal peduncle. Vertical bars are rare although Hubbs (1936: 231) stated that H. b. pcninsulac from Yucatan has 2 to 4 such bars, "like narrow parr marks", behind the shoulder spot. Among 35 young to juvenile individuals from the Rio Atoyac (UMMZ 162144) are 8 with 2 to 5 faint bars anteriorly; 7 of these have 13 dorsal rays, the number that overlaps that of H. Jonesi at this same locality. However, in no other features do these specimens resemble /o/a'.s/; measurements of the basal length of the dorsal tin and predorsal length yielded calculated ratios of less than 1.0 in all eight specimens (see Table 5). Bars thus appear to be only rarely developed in H. bimaculata. The basicudal spot is somewhat variable in size and position. Typically it is large, roundish, more or less equal to the diameter of the eye, set higher than in /V>//<'.s/ and mostly on the caudal tin. However, in a collection from the Rio Coatzacoalcos basin (Ri'o Sarabia, Oaxaca, UMMZ 178533), the spot lies almost entirely on the base of the caudal tin, generally only slightly above the body axis, and varies from round to tri- angular with the apex of the triangle (often drawn out) directed posteriorly. This popula- tion (corresponding to H. b. taeniata of Regan) also shows a well-developed midlateral stripe that is disrupted in young specimens.
Biology. — Meek (1902: 98) reported that this species probably gives birth "near the first to the middle of June" (at Jalapa, Veracruz, 1,427 m). Possibly this is true but if so, successful fertilization and development take place later in the year than it does in H. Jonesi. A collection (UMMZ 108614) made on 22 March from Cordoba (872 m) contains individuals as small as 14 mm standard length, indicating that brood production had been under way for some time. As already indicated (see Biology, H. Jonesi), both species had produced young in the Ri'o Atoyac (about 600 m) by late December.
Mature males of//, biiuaculata. like those of//, jonesi, vary greatly in. size: 25 (1), 27 (1), 29 (2), 30 (1), 31 (1), il (3), i:> (6), 34 (2). 35 (3), 37 (1), 38^2), 39 (2), 40 (2), 43 (1), 44 (3), 45 (5), 46 (1), 47 (2), 48 (3), 49 (3), 50 (1), 51 (1), 52 (1), 48, avg. 39.4 mm (UMMZ 183902, Cosolapa). The largest of 20 immature males in this collection was 51, the smallest 40, and 16 were 41 or more mm long (all these males had the gonopodium elongated but undifferentiated at the tip). The 74 mature females in this collection, varying from 43 to 76 mm long, averaged 58.1 mm.
249
Synipatry between H. hiniaciilatu and //. joncsi has already been discussed (see Biology, H. ioiwsi).
Raii}^c. — Ihe precise northern limit of//, himaculata on the Atlantic coastal plain is uncertain, but it evidently does not extend to the Rio Nautla basin, which as far as known contains only //. Joncsi. The northernmost collection known to me is from the Rio Misantla (M74-6, in UMMZ; Fig. 4), an independent tributary to the Gulf of Mexico lying just southeast of the Rio Nautla, Veracruz; this stream is north of Jalapa, which lies near the northernmost inland limit of H. himaculata. In Mexico the species occurs at elevations from near sea level to at least 1,430 m (Jalapa).
Spccinn-ns examined (All in Mexico). — Oaxaca: UMMZ 17853.1 (52), Rio Sarabia on Trans-Isthmian Hwy; UMMZ 18.1902 (757), Cosolapa. Veracruz: U.SNM ,1102.1 (5) and 45489 (27), Mirador; UMMZ 108614 (207), Ki'o Chico, Cordoba; UMMZ 124234 (h9). 4 km E ot Papaloapan ( = E1 Hiilc); UMMZ l(i2144 (.18), Rio Atovac. (1.5 km N ot Potrero Viejo; UMMZ 181.109 (35), Cordoba: UMMZ 184512 (94), 32.5 km N ol Jose Cardel.'
PHYLOGENY
In considering the relationships of phyletic lines within the subgenus P.sciulo.xiphop/ionis. it is clear from Table 5 and Figures 2 and 3 that //. Joncsi is less specialized than //. himaculata. The gonopodium, especially, is of simpler construction in joncsi. Although several species of this subgenus are yet to be described from Guatemala. I have examined all of them and conclude that none is more primitive than //. Joncsi. In body form and proportions, position and size of the dorsal tin, head shape, length of mandible, and detailed architecture of the gonopodium, each of the Guatemalan species shows some features that indicate a less generalized condition than is found in H. j'oncsi. The species represented by UMMZ 193893 (Alta Verapaz, Guatemala) is perhaps as close to Joncsi as is any of the Guatemalan species, but it shows certain modifications about the distal end of the gonopodium (e.g., thickening of ray 3. increased number of small segments in ray 4a) that, to me. mark it as more specialized.
LITERATURE CITED
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1950. Contribucion al conocimiento de los peces de la region de los Llanos, estado de Puebla (Mexico). An. Esc. Nac. Cien. Biol., b (1-4): 81-107. tigs. 1-3.
1972. Algiinos ejemplos de especiacion en peces niexicanos. Acta Polit.. Mex., 13(b0): 81-89. tigs. 1-6. Barbour. CD.
1973. A biogeographical history of Chirosioiiui (Pisces: Atherinidae): a species tlock from the Mexican Plateau. Copeia. 1973(3):' 533-556, tigs. 1-18.
Boiland. R.F., and CD. Barbour
MS. Svstematic status ot the genus Fohhuui Dc Buen (Pisces: Atherinidae). Darnell, R.
1962. Fishes of the Rio Tamesi and related coastal lagoons in east-central Mexico. Publ. Inst. Mar. Sci., 8: 299-365, tigs. 1-2. Fitzsinions. J.M.
1972. A revision of two genera of goodeid tlshes (Cyprinodontitormes, Osteichthyes) troni the Mexican Plateau. Copeia, 1972(4): 728-756, tigs. 1-10. Carman, S.
1895. Ihc cyprinodonts. Mem. Mus. Comp. Zool.. Harvard Coll.. 19: 1-P9, pis. 1-12. Gunther, A.
1874. Descriptions of new species of tlshes in the British Museum. Ann. Mag. Nat. Hist., ser. 4, 14: .168-3^1. Meckel, J.
1848. Fine ncue Gattung von Poecilien mit rochenartigen Amklammcruiigs-Organc. .Sitzber. K. Akad. Wiss. Wien, Math^Natwiss. CI.. 1: 289-.l()3. pis. 8-9. Hulibs, CL.
1924. .Studies of the tlshes of the order Cyprinodontes. 1-I\'. Misc. Publ. Mus. Zool. Univ. Mich.. 13:
1-31, pis. 1-4. 1926. Studies of the tlshes of the order Cyprinodt)ntcs. \ 1. Material for a revision of the American genera
and species. Misc. Publ. Mus. Zool. Univ. Mich.. 16: 1-86. pis. 1-4. 1936. Fishes of ihc 'i ucatan Peninsula. Cam. Inst. Wash. Publ. 45": 15"-28", tig. 1. pK. 1-15.
250
Hubbs. C.L. and K.F. Lagler
1958. Fishes of the Great Lakes region. Bull. Cranbrook Inst. Sci., 26: i-xiii, 1-213, figs. 1-251. col. pis. 1-44. Jordan. D.S., and B.W. Evermann
18%. The fishes ot North and Middle America. Bull. U.S. Nat. Mus., 47(1): I-LX. 1-1240. Meek. S.E. '
1902. A contribution to the ichthyology of Mexico. Field Col. Mus., Publ. 65, Zool. Scr. 3(6): 63-128, pis. j
14-31. 1904. The fresh-water fishes of Mexico north of the Isthmus of Tehuantepec. Field Col. Mus., Publ. 93, Zool. Ser. 5: i-lxiii, 1-252, figs. 1-72, 1 map, pis. 1-17. Menzel, B.W., and R.M. Darnell
1973. Systematks of Poecilia mexicana (Pisces: Poeciliidae) in northern Mexico. Copeia, 1973(2): 225-237. figs. 1-3. Miller. R.R.
1966. Geographical distribution of Central American freshwater fishes. Copeia, 1966(4): 773-802, figs. 1-5. Regan. C.T.
1904. Descriptions of new or little-known fishes from Mexico and British Honduras. Ann. Mag. Nat. Hist., ser. 7. 13: 255-259.
1905. A collection of fishes made by Dr. H. Gadow in southern Mexico. Ann. Mag. Nat. Hist., ser. 7, 16: 361-363.
1906-08. Pisces. In: Biologia Centrali-Americana, 8: 1-203. 7 figs., pis. 1-26.
1907. Descriptions of six new freshwater fishes from Mexico and Central America. Ann. Mag. Nat. Hist.,
Ser. 7. 19: 258-260. 1913. A revision of the cyprinodont fishes of the subfamily Poeciliinae. Proc. Zool. Soc. London, 1913:
977-1018, figs. 168-173, pis. 99-101. Rosen. D.E.. and R.M. Bailey
1963. The poeciiiid fishes (Cyprinodontiformes). their structure, zoogeography, and systematics. Bull. Am. Mus. Nat. Hist.. 126: 1-176. figs. 1-61, maps 1-19, pis. 1-2.
Rosen, D.E., and M. Gordon
1953. Functional anatomy and evolution of male genitalia in poeciiiid fishes. Zoologica, 38(1): 1-47, figs. 1-47. pis. 1-4. Rosen, D.E.. and J.R. Mendelson
1960. The sensory canals of the head in poeciiiid fishes (Cyprinodontiformes). with reference to dentitional types. Copeia, 1960(3): 203-210, figs. 1-4.
Rosen, D.E., and A. Tucker
1961. Evolution of secondary sexual characters and sexual behavior patterns in a family of viviparous fishes (Cyprinodontiformes: Poeciliidae). Copeia, 1961(2): 201-212, figs. 1-3.
Schultz. R.J. ."and R. Thibault
MS. Reproductive strategies among viviparous fishes. Amer. Nat. Scrimshaw, N.S.
1946. Egg size in poeciiiid fishes. Copeia. 1946(1): 20-23. Steindachner. F.
1863. Beitrage zur Kcnntniss der Scianoiden Brasiiiens und der Cyprinodonten Mejicos. Sitzber. K. Akad. Wiss., Wien, Math.-Natwiss.. 48(1): 162-185. pis. 1-4. Tamayo. J.L.
1964. The hydrography of Middle America, pp. 84-121. figs. 1-6. //;: Handbook of Middle American Indi- ans, vol. 1. R. Wauchope and R.C. West, eds. Univ. Texas Press, Austin.
Turner. C.L.
1937. Reproductive cycles and superfetation in poeciiiid fishes. Biol. Bull., 72(2): 145-164. von Muller. J.W.
1865. Reisen in den Vereinigten Staaten, Canada und Mexico. Vol. 3. Leipsig. pp. i-xii, 1-643. Wooiman, A.J.
1894. Report on a collection of fishes from the rivers of central and northern Mexico. Bull. U.S. Fish Comm.. 14(1895): 55-66. pi. 2.
4
I
Museum of Zoology, The University of Michigan. Ann Arbor. Michigan 48104 U.S.A.
SAN (^(sn
LITHOSTRATIGRAPHIC VARIATIONS
IN THE POWAY GROUP
NEAR SAN DIEGO, CALIFORNIA
GARY L. PETERSON AND MICHAEL P. KENNEDY
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OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
VOL. 17, NO. 18
6 DECEMBER 1974
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LITHOSTRATIGRAPHIC VARIATIONS IN THE POWAY GROUP NEAR SAN DIEGO, CALIFORNIA
GARY L. PETERSON AND MICHAEL P. KENNEDY
ABSTRACT. — The Eocene Poway Group consists of two mutually intertongued bodies of rock, or iithosomes. One consists predominantly of coarse conglomerate of fluvial origin and is located principally in the eastern San Diego area. The other consists of sandstone and siltstone and lies predominantly west of the conglomerate lithosome. Tongues of the conglomerate lithosome extend toward the west and include the Stadium Conglomerate and the herein named Pomerado Conglomerate (Upper Eocene). Tongues of the sandstone lithosome extend toward the east and pinch out within the conglomerate. Lower sandstone tongues constitute the Mission Valley Formation, and an upper tongue is herein named the Miramar Sandstone Member of the Pomerado Conglomerate (Upper Eocene). The sandstone lithosome is partly of nearshore-marinc and partly of nonmarine origin, whereas the conglomerate is of tluviatile origin. The conglomerate was deposited as a delta at the site where a large Eocene river emerged onto a low -lying coastal plain.
One of the most distinctive and widespread stratal units in the San Diego area is referred to in the older literature as the "Poway Conglomerate" (Ellis and Lee. 1919; Hanna. 1926; Bellemin and Merriam, 1958; and many others). More recently, Kennedy and Moore (1971) recognized that this Eocene stratal unit is composed not only of conglomerate, but also contains at least one widespread mappable sandstone unit. They revised the nomenclature accordingly and raised the rank of the "Poway Conglomerate" to the Poway Group. Within the Poway Group, Kennedy and Moore (1971) recognized a lower rock unit designated the Stadium Conglomerate, a middle unit dominated by fine-grained sandstone designated the Mission Valley Formation, and a third unnamed conglomerate, herein designated the Pomerado Conglomerate.
A geologic map of part of San Diego, and adjacent areas, now completed at a scale of 1:24,000 (Kennedy and Peterson, 1974). shows the distribution of these formations and their relationships to one another. A small portion of that map is included here as Fig- ure 1. The purpose of this paper is to name, briefly describe, and establish type sections for new rock units, as well as to describe the vertical and lateral variations in lithologic character within the Poway Group.
The lateral distribution of rock types within the Poway Group is best illustrated and explained by utilizing the lithosome concept of Wheeler and Mallory (1956). rather than more traditional lithostratigraphic units (formations and members). Briefly, a lithosome is a rock body of uniform character that intertongues with one or more other rock bodies of uniform but differing character. The individual tongues of the lithosome are referred to by Wheeler and Mallory as lithostromes, and are here what we have mapped as formations and members (Fig. 1).
The lithostratigraphic variation in the Poway Group is most pronounced in an east-west direction (Fig. 2). The Poway Group is subdivided into two mutually intertongued Iithosomes, each representing a different depositional environment. One lithosome is dominated by conglomerate and is herein informally referred to as the conglomerate lithosome. The other is dominated by soft, friable sandstone and is hereafter referred to as the sandstone lithosome.
The basically simple lithosomal relations that we illustrate in Figure 2 are in part interpretational, since the Poway Group is only partially presened. The principal complicating factor is the presence of the Lindavista Terrace, a Pleistocene wave-cut platform capped by a thin veneer of reddish-brown sandstone and conglomerate (the Lindavista Formation). Because of this later erosional episode, the Poway Group has a large notch removed, and the variations within this missing portion of the group are no longer evident. This erosional notch affects the western part of the Poway Group, or that
SAN DIEGO SOC. NAT. HIST., TRANS. 17(18): 251-258, 6 DECEMBER 1974.
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portion which we interpret to be dominated by the sandstone lithosome. We have reconstructed within this missing portion what we consider to be the most reasonable lithostratigraphic variation to account for the relations observed and mapped within the preserved portion of the section.
The lithosomes, together with their lithostromes, which are mappable rock units of member and formational rank, are briefly described below. A discussion of the regional genetic significance follows in the last section.
CONGLOMERATE LITHOSOME
The conglomerate lithosome is composed of one of the most distinctive rock types in the San Diego area. The clasts range in size from pebbles to small boulders, and locally are up to nearly a meter in diameter. Clasts over 30 cm in diameter are rare. The clasts are subrounded to rounded and are set in a medium- to coarse-grained sandstone matrix.
I
253
In general field appearance the conglomerate is so distinctive that with only some minor exceptions involving reworking, it can be readily distinguished from the older and younger conglomerates of the area (Peterson, 1970). Thin beds and lenses of cross-stratit'ied sandstone lithologically similar to the conglomerate matrix occur throughout the section and increase in persistence toward the west. The conglomerate is chiefly nonmarine, and we interpret the interstratified sandstone to be partly marginal marine but predominantly of fluvial origin.
The conglomerate is characterized by the Poway suite of clasts (Bellemin and Merriam, 1958; DeLisle et al., 1965; Woodford et al., 1968; Peterson, 1971), an exotic assemblage consisting predominantly of rhyolitic to dacitic volcanic and volcaniclastic rocks with a smaller but significant proportion of quartzite. This assemblage of clasts first appears in the stratigraphic succession at San Diego in the Eocene (Peterson and Nordstrom, 1970), is extensively reworked into post-Eocene rock units, and in most places is the dominant clast suite found in the modern stream and beach gravels. The Poway clasts are exceedingly durable, having travelled an exceptionally long distance to the site of deposition. Their probable area of origin seems to be on the Sonoran side of the Gulf of California (Bellemin and Merriam, 1958; DeLisle et al., 1965; Woodford et al., 1968; Minch, 1970, 1972).
The character of the conglomerate lithosome is surprisingly uniform throughout the San Diego area. It varies little either geographically or stratigraphically. Thus the Stadium Conglomerate is lithologically nearly identical to the Pomerado Conglomerate. These conglomerates can be differentiated only because they are separated by the Mission Valley Formation.
Stadium Conglomerate. — The lower conglomerate lithostrome was designated the Stadium Conglomerate, with a type section near San Diego Stadium in Mission Valley. This rock unit is very widespread and has been recognized throughout the San Diego region (Kennedy and Moore, 1971; Peterson, 1971). Its thickness is highly variable and ranges from a few meters to perhaps 75 m. In general it is thickest and most typically developed in the central San Diego area and becomes progressively thinner to the north and west. The Stadium Conglomerate is overlain by the finer-grained Mission Valley Formation. The contact between the two units is gradational, and locally the two units are intertongued.
Pomerado Conglomerate. — The upper conglomerate lithostrome is here named the Pomerado Conglomerate. A well-exposed section, here designated the type section, is located along the roadcuts of Pomerado Road and Sycamore Canyon access road between San Diego and Poway (location P in Figure 1).
At the type section, the Pomerado Conglomerate gradationally overlies the Mission Valley Formation, a unit consisting of gray to light brown sandstone containing a small amount of whitish caliche, scattered pebbles, and small cobbles of rhyolitic rock. The basal Pomerado contact is placed at the base of a 7 m massive conglomerate of typical Poway type. Overlying the conglomerate is a 7 m thick medium-grained, soft, friable sandstone resembling the underlying Mission Valley Formation but interpreted here as a lens of sandstone within the Pomerado Conglomerate.
Overlying the sandstone lens is a 14 m thick massive cobble conglomerate with the typical Poway suite of clasts, many of which are fractured in situ. This conglomerate grades upward into a sandstone containing small scattered pebbles and a thin bed of pebble conglomerate. Thickness of the sandstone is 7 m. It is overlain by 5 m of cobble conglomerate with some clasts up to 30 cm diameter. Overlying this conglomerate is a 2 m thick sandstone lens which is in turn overlain by a 1 m massive cobble conglomerate bed. Overlying the conglomerate is a 3 m bed of soft, friable, medium-grained sandstone containing some Poway-type pebbles. The highest exposed unit of the Pomerado Conglomerate is a 10 m thick bed of cobble to boulder conglomerate. Some of the boulders are up to 30 cm in diamter and many are fractured in situ. Some thin, mostly discontinuous beds and lenses of sandstone are present in this otherwise massive conglomerate bed.
The top of the type section of the Pomerado Conglomerate ends at the crest of the
254
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I
hill. In this area no further units overlie the Pomerado. Farther to the south, the Pliocene
San Diego Formation unconformably overlies the Pomerado Conglomerate.
The Pomerado Conglomerate is gradational with the underlying Mission Valley Formation throughout the map area (Fig. 1) and much of the San Diego region. To the east, however, the Mission Valley Formation becomes thinner and finally pinches out between the Pomerado Conglomerate and Stadium Conglomerate.
No fossils have been found in the Pomerado Conglomerate; it is here considered to be Late Eocene in age, as it is gradational with and overlies the Mission Valley Formation, which is Late Eocene (Kennedy, 1973).
The Pomerado Conglomerate is not nearly as widespread as the Stadium Conglomerate, but the difference in distribution is at least in part a matter of preservation. The Stadium Conglomerate extends beneath the Lindavista wave-cut platform and is present in much of the western part of the San Diego area. The Pomerado Conglomerate, for the most part, terminates at the old sea cliff associated with the Lindavista Terrace (Fig. 2).
Within part of the Pomerado Conglomerate is a moderately widespread sandstone and siltstone unit here designated the Miramar Sandstone Member. We interpret this as a tongue of the sandstone lithosome (Fig. 2) described below.
SANDSTONE LITHOSOME
The sandstone lithosome is composed primarily of soft white, gray, yellow, and light brown friable sandstone with interbedded soft gray to green-gray siltstone. In general, this rock type crops out much more poorly and is not nearly as obvious as the conglomerate. In addition, the sandstone and siltstone rock units tend to be covered with slopewash derived from the overlying conglomerate. However, exposures are present at road cuts and because of a distinctive topographic expression their distribution can be mapped with some degree of certainty.
In addition to the dominant lithology, the sandstone lithosome contains random thin beds and lenses of conglomerate. The conglomerate is similar in all respects to that of the conglomerate lithosome and is considered to represent minor tongues of that unit. The conglomerate beds and lenses locally constitute up to about 20 per cent of the sandstone lithosome, which is also equivalent to the maximum per cent of sandstone beds and lenses locally present in the conglomerate lithosome.
A marginal marine and nonmarine environment of deposition for the sandstone lithosome is based on the presence of fossil mammals, tlsh, lagoonal oysters, and nearshore-marine moUusks (Kennedy, 1973).
Mission Valley Formation. — The Mission Valley Formation is a rock unit named by Kennedy and Moore (1971), with a type section along the south side of Mission Valley near State Highway 163 (old U.S. 395). From that locality the Mission Valley Formation extends over a wide area that includes parts of the La Mesa, La Jolla, Del Mar, and
255
Poway IVi minute quadrange. The Mission Valley Formation is thickest in its westernmost exposures near Mission Valley. To the east, within the upper Mission Gorge area, the lower part of the formation intertongues with the upper part of the Stadium Conglomerate (Fig. 2). An upper tongue of the Mission Valley Formation can be seen in upper Murphy Canyon but pinches out rapidly toward the eastern boundary of the Poway and La Mesa quadrangles. Beyond this line, the Pomerado and Stadium Conglomerates are in contact. A Late Eocene age has been assigned to the Mission Valley Formation based on the presence of Tejon mollusks in the nearshore-marine part of the section and Uinta C mammals in the nonmarine part (Kennedy, 1973).
Miramar Sandstone Member of Pomerado Conglomerate. — The uppermost tongue of the sandstone lithosome is found entirely within the Pomerado Conglomerate in the general vicinity of Miramar Reservoir. Lithologically, it is identical to the Mission Valley Formation, and its outcropping characteristics are similar. However, because this unit is wholly within the Pomerado Conglomerate, and because it is nowhere in contact with the Mission Valley Formation, we are here designating it the Miramar Sandstone Member of the Pomerado Conglomerate. We interpret the Miramar Member as well as the Mission Valley Formation to be tongues of the sandstone lithosome, but this interpretation depends on evidence within that part of the Poway Group that has been erosionally removed by the cutting of the Lindavista Terrace (Fig. 2).
The type section for the Miramar Sandstone Member is here designated to be along the fire road extending along the ridge at the northern margin of Miramar Reservoir (see Fig. 1). At the type section, the Pomerado overlies the Mission Valley Formation which consists of soft, friable, red to brown weathering sandstone. The lower part of the Pomerado consists of 17 m of pebble to cobble conglomerate composed of the Poway suite of clasts.
Overlying the lower conglomerate is 20 m of soft medium- to coarse-grained, gray to gray-brown, red-brown weathering sandstone here designated the Miramar Sandstone Member. The sandstone is best exposed in gullies at the edge of the fire road. Locally it is pebbly, containing the Poway suite of clasts, and locally it is fractured with the fractures filled with caliche. In all respects, the Miramar Member strongly resembles the Mission Valley Formation.
The Miramar Member is overlain by 32 m of massive cobble conglomerate, the upper unit of the Pomerado Conglomerate in this section. The conglomerate is dominated by cobbles and small boulders with some of the clasts ranging up to 30 cm in diameter.
From the type section, the Miramar Member can be traced around the hills surrounding Miramar Reservoir. Where traced to the east it pinches out within the Pomerado Conglomerate (Figs. 1, 2).
No fossils were found within the Miramar Member, although the general lithologic similarity to the Mission Valley Formation suggests a similar environment of deposition. The fact that it is within the Pomerado Conglomerate, which is gradational with the underlying Mission Valley Formation, suggests an age of late Eocene.
REGIONAL IMPLICATIONS
In the Late Eocene in the San Diego area a large river valley emerged along the Pacific Coast. This ancient valley, called the Ballena Channel by Minch (1970, 1972), is traceable eastward almost to the Elsinore Fault. It enters the San Diego area in the vicinity of San Vicente Reservoir. There are narrowly distributed channel deposit, (the "Ballena Gravel") rapidly fans out and grades westwardly into the Late Eocene stratal units of the San Diego area (Kennedy and Moore, 1971; Peterson, 1971).
Apparently the Ballena Channel carried much of the coarse sediment, especially that of the coarse conglomerate characterized by "Poway" clasts, which is now so abundant in the Eocene succession of the San Diego area. The Ballena River entered the San Diego embayment from the east, apparently dropping much of its coarsest load in the area of lowering gradient as it entered the coastal plain of San Diego. The conglomerate lithosome represents predominantly fiuvial deposits. These conglomerate beds grade
256
laterally and intertongue westward (also to an extend northward and southward) with the sandstone lithosome. #
The sandstone lithosome is at least partially marine. Thus a significant portion of the tine detritus may have been derived via longshore transport or roughly at right angles to the westward paleoslope indicated by the Ballena Channel. In addition , much of the fine detritus appears to be supplied by local minor drainage channels (Peterson, 1971).
Generally continuous submergence was necessary to preserve the rocks of the Poway Group. The large scale intertonguing of the two distinctive lithosomes can be interpreted in several ways. First, the eastward extensions of the partially marine sandstone-siltstone lithosome indicate eastward transgression of the strand line. The maximum transgression would be represented by the Mission Valley Formation. The regressive phases would be represented by the tluvial conglomerate lithosome, with the maximum regressions represented by the Stadium and Pomerado Conglomerates. The transgressive-regressive fluctuations could have been caused by interacting eustatic sea-level changes and local tectonic subsidence. Such fluctuations tit well with earlier transgressive-regressive episodes represented within the underlying La Jolla Group (Kennedy and Moore. 1971).
A second possible interpretation is that the size and position of the conglomerate lithosome may be due to variations in the amount of coarse fluvial detritus being transported into the San Diego area. That is, in times of voluminous supply, such as during the deposition of the Stadium and Pomerado conglomerates, a conglomeratic fan-delta could have built westward at the expense of the marine environment. During times of less fluvial sediment supply during the subsidence, the marine environment might again have encroached eastward.
A third possibility is that the intertonguing lithosomes indicate a combination both of changes in rate of submergence and of changes in rate of sediment influx. We consider this possiblity the most plausible.
LITERATURE CITED
Bellemin, G.J., and R.H. Merriam
1958. Petrology and origin of the Poway Conglomerate. San Diego County. California. Geol. Soc. Amer. Bull. 69: 199-220. DeLisle. M., J.R. Morgan, J. Heldenbrand, and G. Gastil
1965. Lead-alpha ages and possible sources of metavolcanic rock clasts in the Poway Conglomerate, south- west California. Geol. Soc. Amer. Bull. 76: 1069-1074. Ellis. A.J., and C.H. Lee
1919. Geology and ground waters of the western part of San Diego County, California. U.S. Geol. Survey Water-Supply Paper 446: 1-321. Hanna. M.A.
1926. Geology of the La Jolla quadrangle, California. Univ. Cal. Publ. Geol. Sci. 16: 247-398. Kennedy. M.P.
1973. Stratigraphy of the San Diego embayment, California. Ph.D. Thesis. Univ. California (Riverside). Kennedy. M.P., and G.W. Moore
1971. Stratigraphic relations of Upper Cretaceous and Eocene formations. San Diego coastal area, Cali- fornia. Amer. Assoc. Petroleum Geol. Bull. 55: 709-722.
Kennedy. M.P., and G.L. Peterson
1974. Geology of the La Mesa, Poway. and southwest quarter of the Escondido quadrangles, eastern San Diego metropolitan area, California. California Div. Mines and Geol. Bull. 200B.
Minch, J. A.
1970. Early Tertiary paleogeography of a portion of the northern Peninsular Ranges. In Pacific slope geology of northern Baja California and adjacent Alta California. Amer. Assoc. Petroleum Geol. (Pacific Sec.) Fall Field Trip Guidebook: 4-9.
1972. The Late Mesozoic-Early Tertiary framework of continental sedimentation, northern Peninsular Ranges, Baja California, Mexico. Ph.D. Thesis. Univ. California (Riverside).
Peterson, G.L.
1970. Distinctions between Cretaceous and Eocene conglomerates in the San Diego area, southwestern California. In Pacific slope geology of northern Baja California and adjacent Alta California. Amer. Assoc. Petroleum Geol. (Pacific Sec.) Fall Field Trip Guidebook: 90-98.
1971. Stratigraphy of the Poway area, southwestern California. San Diego Soc. Nat. Hist. Trans. 16: 225-236.
257
Peterson. G.L.. and C.E. Nordstrom
1970. Sub-La Jolla unconformity in vicinity of San Diego, California. Amer. Assoc. Petroleum Geol. Bull 54: 265-274. Wheeler, H.E., and V.S. Mallory
1956. Factors in lithostratigraphy. Amer. Assoc. Petroleum Geo!. Bull. 40: 2711-2723. Woodford, A.O.. E.E. Welday, and R.H. Merriam
1968. Siliceous tuff clasts in the upper Paleogene of southern California. Geol. Soc. Amer. Bull. 79: 1461-1486.
Department of Geological Sciences. San Diego State University, San Diego. California. California Division of Mines and Geology. Geological Research Division, Scripps Institution of Oceanography. La Jolla, California.
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THE AUTECOLOGY OF XANTUSIA HENSHAWI HENSHAWI (SAURIA: XANTUSIIDAE)
HARVARO
JULIAN C. LEE
TRANSACTIONS
OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
VOL. 17, NO. 19
22 APRIL 1975
THE AUTECOLOGY OF XANTUSIA HENSHA WI HENSHA WI (SAURIA: XANTUSIIDAE)
JULIAN C. LEE
ABSTRACT. — Xantusia henshawi henshawi is a secretive, crevice-dwelling lizard confined to southern California and adjacent Baja California, Mexico. Field studies during portions of four years at two sites in western San Diego Co. and studies of musuem specimens revealed that the distribution of this saxicolous species is correlated with the presence of granitic rocks. The availability of suitable rock crevices is an important factor limiting both population size and geographic distribution. Brush fires may generate additional crevices by accelerating the exfoliation of boulders.
This species is slow-growing, late-maturing, long-lived, and has the lowest reproductive potential yet reported for any lizard. Males probably first breed at about 2.5 years; females breed first at 3.5 years, and produce one brood (mean size 1.46) per season. Head and tail length exhibit allometric growth relative to snout-vent length; linear growth is determinant. The frequency of caudal autotomy is high among adults and probably results from intra-specific fighting rather than predation. The mortality rate from all causes is low.
Xantusia h. /zens/iauj occupies a thermally buffered microhabitat, and in summer maintains body tempera- tures within approximately the same limits day and night. This species is eurythermic, showing no distinct temperature preference. Body temperature is highly dependent on substrate temperature.
The life history of this lizard is similar to that of Xantusia vigilis.
Of the approximately 3,000 living species of lizards, the life histories of perhaps no more than 50 have been studied thoroughly (Fitch, 1970). Because of its limited and highly disjunct distribution, the family Xantusiidae is of particular interest. Yet the only general life history for any xantusiid, is Miller's (1951) study of Xantusia vigilis. The present study, designed to fill partially this gap in our knowledge of lizard ecologies, presents an analysis of the life history of Xantusia henshawi.
Possibly because of its limited distribution, secretive habits, and specialized microhabitat, little information has been published on this species since its discovery in 1893. Authors who have discussed aspects of the biology of X henshawi — often in casual or anecdotal fashion — include: Atsatt (1925), Brattstrom (1951, 1952, 1965), Grinnell and Camp (1917), Klauber (1926, 1931. 1939), Lee (1974), Mautz and Case (1974), Scott (1971), Shaw (1949), and Stephens (1921).
Description. — Xantusia henshawi is a small lizard. Adult males average 56 mm SVL and weigh about 2.9 g. Adult non-gravid females average 62 mm and 3.3 g. These lizards are dorso-ventrally compressed (Fig. 1), a feature associated with their crevice dwelling habits. The limbs are well developed, pentadactyl, and the digits bear small, strongly recurved claws. The head is covered with enlarged, symmetrical shields; the dorsal and lateral body surfaces and throat are covered with granular scales; the venter bears 14 longitudinal rows of enlarged rectangular plates; and the tail is covered with whorls of smooth, rectangular scales. Femoral pores are present in both sexes. As in all xantusiids, eyelids are lacking, the eye being covered by a transparent spectacle. The pupil is vertically elliptical. This species exhibits a daily rhythmic color change (Atsatt, 1939): during the day, the animal is dark gray or black with a fine yellowish reticulum; at night the yellowish network expands, and the animal becomes grayish with dark spots. I Distribution. — Prior to 1970, X. henshawi was known only from "Rocky areas on
both sides of the mountains from northern Riverside Co., California, to the San Pedro Martir Mountains, Lower California" (Stejneger and Barbour, 1943; see also maps in Stebbins, 1954, 1966). Webb (1970) described a disjunct population which he named Xantusia henshawi bolsonae, from a single locality in eastern Durango, Mexico, 1280 km
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Figure 1. Adult male Xantusia henshawi henshawi. 56 mm snout-vent length.
southeast of the nearest population of the nominate race. Figure 2 presents the distribution of X. h. henshawi based upon published localities, museum records, and data from this study.
Webb (1970) summarized variation in X. h. henshawi based upon an examination of 108 specimens from throughout its geographic range. Comparison with Webb's data indicated that the Mt. Woodson and Lee Valley populations sampled in this study are referable to X h. henshawi (Table 1).
Habitat. — X. henshawi is saxicolous and is rarely found far from crevices, especially those formed by the exfoliation of granitic boulders (Fig. 3). Such rocks are a requirement for this species, and their absence is probably a factor limiting both distribution and population density.
Chaparral is the principal plant community in the range of the nominate race, although ecotonal chaparral-coastal sage scrub situations are inhabited in western San Diego Co., as is the chaparral-creosote bush scrub ecotone in eastern San Diego Co., southwestern Imperial Co., and portions of Riverside Co.
Summers are generally hot and dry throughout the range of this subspecies. However, the rock-crevice microhabitat occupied hy Xantusia henshawi henshawi protects
116
— r-
Riverside
• San Diego
1 Imperial
1
I'
Baja California
-3f
Figure 2. Distribution of Xantusia henshawi henshawi. Open arrow indicates study site 1, solid arrow indicates study site 2.
261
TABLE 1 . Comparison of taxonomic characters in 20 adult Xantusia henshawi henshawi from Mount Wood- son, San Diego County, California, 20 adults from Lee Valley, San Diego County, and 108 specimens of the subspecies from throughout its range (Webb, 1970). The first figure is the mean; the figures in parentheses, the range.
Character Webb, 1970 Mount Woodson Lee Valley
Number of infralabials 5.1 (4-7) 5.8 (5-6) 6.4 (5-7)
Number of supralabials 6.2(5-8) 6.7(6-9) 7.0(6-8)
Head width/body length 0.18(0.16-0.28) 0.17(0.16-0.18) 0.17(0.16-0.19)
Number of dorsal granules at midbody 62.8(56-71) 61.3(55-66) 63.4(57-69)
Number of transverse rows of ventral scales 32.7(30-36) 34.1(32-36) 33.0(31-34)
Number of enlarged scales on gular fold 10.3(7-14) 11.2(9-13) 11.8(7-14)
Number of temporal scales 5.6 (4-8) 5.6 (5-7) 5.6 (4-8)
Number of femoral pores 10.7(7-16) 11.0(10-13) 11.3(10-14)
them from temperature extremes. This thermal buffering effect is illustrated in Figure 4. The meager rainfall (often less than 36 cm per year) is mostly restricted to the cooler fall, winter, and spring months (Fig. 5).
The possible ecological relationships of vertebrates known to coexist with X. h. henshawi are indicated in Table 2.
MATERIALS AND METHODS
Field work at two sites was conducted intermittently in 1968, 1970, and 1971, and systematically from April through October, 1972. Site 1, in Lee Valley, San Diego Co., California (Fig. 2) is described elsewhere (Lee, 1974). Site 2 is located 4.8 km north and 4.8 km east of Poway, San Diego Co., California (Fig. 2). The site includes portions of Warren Canyon and the south and southwest slopes of Mount Woodson. Elevation ranges from 430 m at the bottom of Warren Canyon to 890 m at the top of Mount Woodson. The steep flanks of Warren Canyon and tlie slopes of Mount Woodson are strewn with exfoliating granitic boulders and covered with chaparral (Fig. 6). Portions of the area were burned in 1967.
In this investigation 735 living lizards and 171 preserved specimens from the San Diego Society of Natural History (SDSNH) were examined. Locality data were obtained from collections in the San Diego Society of Natural History, Museum of Vertebrate Zoology, Los Angeles County Museum of Natural History, and the California Academy of Sciences.
Population structure. — From late April to mid October, 1972, samples were taken at approximately monthly intervals from contiguous areas at site 2. Specimens were captured by removing granitic flakes with a crowbar (see Klauber, 1926). Weights and measurements were taken in the laboratory within 24 hours of capture. Weights were taken on a Mettler balance and read to the nearest 0.01 g. Snout-vent, tail, and axilla- groin lengths were measured with a plastic millimeter rule and read to the nearest mm. Head length (anterior margin of auditory meatus to tip of rostrum) and head width (greatest width anterior to auditory meatus) were measured with vernier calipers to the nearest 0.1 mm. Caudal autotomy was noted for each lizard, as was the number of femoral pores and the sex of each adult. All lizards were released unharmed in the approximate area of capture. The same data, with the exception of weight, were obtained from specimens in the San Diego Society of Natural History.
Reproduction. — Testes of preserved specimens were measured to the nearest 0.01 mm with an ocular micrometer. Testicular volume was calculated using the formula for the volume of an ellipsoid. Copulatory activity in recently captured lizards was recorded, and gravid females were held in captivity until parturition to provide information on brood size, characteristics of the newborn, and timing of parturition.
262
TABLE 2. Vertebrate associates of Xantusia henshawi henshawi.
Group
Potential Competitors For Food
Potential Predators
Relationship Unknown
Amphibians Lizards
Snakes
Birds
Mammals
Hyla regilla Bufo boreas
Sceloporus occidentalis Sceloporus orcutti Uta stansburiana Urosaurus microscutatus Phrynosoma coronatum Cnemidophorus tigris C. hyperythrus Coleonyx variegatus Phyllodactylus xanti
Numerous insectivorous passerines
Sceloporus orcutti
Lichanura trivergata Lampropeltis getulus Masticophis lateralis Salvadora hexalepis Hypsiglena torquata Trimorphodon vandenburghi Crotalus ruber Crotalus mitchelli
Faico sparverius Buteo jamaicensis Tyto alba Otus asio Bubo virginianus Geococcyx californianus Corvus corax Aphelocoma coerulescens
Neotoma sp. Canis latrans
Pituophis melanoleucas
Numerous granivorous passerines
Dipodomys agilis Perognathus sp. Peromyscus sp. Sylvilagus sp. Myotis subulatus Odocoileus hemionus
Radiographic examination. — Following the technique described by Etheridge (1962), 15 preserved specimens were x-rayed to determine the presence or absence of epiphysial- diaphysial fusion and to verify caudal autotomy in certain specimens.
Thermal biology. — From 14 June through 19 October, 1972, lizards were captured at night at site 1 and the following data were recorded: date and time of capture, sex, cloacal temperature, air temperature (1 cm above substrate), and substrate temperature. Temperatures were taken with a Schultheis rapid equilibrium thermometer and read to the nearest 0.1 C. Cloacal temperatures were read within 10 seconds of capture, and were taken only from lizards which were abroad on boulders.
RESULTS
Sexual dimorphism. — Adult females average 6 mm longer in SVL than adult males (62 mm vs. 56 mm; Fig. 7), and weigh more (3.3 g vs. 2.9 g), but at any given length, males and non-gravid females weigh the same. I found no sexual dichromatism or intersexual differences in relative head length, head width, axilla-groin length, or tail length of adults.
As in many species of lizards, X. h. henshawi has a row of femoral pores along the postero-ventral margin of the thighs. In males they are large and produce an obvious secretion; in females they are small and inconspicuous (Fig. 8). Dissection of preserved specimens confirms that these secondary sex characters permit accurate sexing of adult
263
Figure 3. Crevice formed by the exfoliation of a granitic boulder. Photographed at site 1.
lizards. I interpreted the presence of a waxy plug within the pore as evidence of active secretion. In preserved lizards and in living material, a secretory plug was first evident in males at a SVL of 42 mm and 43 mm respectively. The number of pores ranges from six to 14 per thigh; often the number on one thigh exceeds that on the other by two or three. I found no significant intersexual difference in mean number of femoral pores on the right thigh (males = 11.0, females = 11.2, N = 100 and 97 respectively, t = 1.36, P> 0.2).
0^
a;
a
^
00 02 04
08
10 12 14 Time of Day
16
-t- 18
20 22 24
Figure 4. Twenty-four hour temperature cycles on a granitic boulder. Solid circles indicate temperature on outer surface of exfoliating flake; open circles indicate temperature at edge of crevice; triangles indicate temperature 25 cm inside crevice. Recorded 22 September 1972 at site 1.
264
35
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JFMAMJJASOND
Months
Figure 5. Ten year mean monthly maximum (solid circles) and minimum (open circles) temperatures and mean precipitation for the period 1957-1966 from Ramona, San Diego Co., California, 13.5 km from study site 2. Data from U.S. Weather Bureau, Ramona-Spalding station.
Population structure. — No significant deviation from a 1 : 1 sex ratio exists in adults from site 2 (X^ = 2.81, P> 0.05), or in specimens of first year (21 males, 23 females), second year (12 males, 11 females), or adult lizards (X^ = 2.34, P>0.10) in the SDSNH collected throughout San Diego Co. Figure 7 presents frequency distributions of SVL for six successive monthly samples from site 2. For lizards which produce only one brood per season and in which parturition occurs over a short period, a SVL frequency distribution
Figure 6. Study site 2, Mount Woodson, San Diego Co., California.
265
w
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September
30 35 40 45
55 60 65 70
Snout-vent Length (mm)
Figure 7. Population structure of Xantusia henshawi henshawi. For lizards 44 mm or above, open bars are females, shaded bars are males. Lizards below 44 mm were not sexed. Black bars indicate lizards in the first year of life. October sample is inverted to facilitate comparison of age classes.
will be polymodal, with the modes representing size classes, which in turn represent age classes. Thus in the October sample, lizards 29 to 33 mm SVL are deemed newborn (see reprodution, below), those 37 to 40 mm are one year old, those 43 to 49 mm two years old, and those 52 mm and above are three years or older. Designation of age class boundaries is sometimes arbitrary, especially for older lizards where growth rates are slower, causing size classes to overlap. Thus in the July sample I consider as first year lizards those with a SVL of 40 mm or less. To the extent that age classes can be inferred from size classes, Figure 7 indicates that in each month lizards three years or older comprised over 50 per cent of the sample. Over the entire six months, lizards in the first year of life comprised 18.2 per cent, second year lizards 9.3 per cent, and lizards in the third year or older, 72.5 per cent of the total sample.
266
Figure 8. Femoral pores of adult male and female Xantusia henshawi henshawi. Pores are darkened for emphasis.
Growth. — A statistical approximation of growth is obtained by plotting the mean SVL for each size class against time. Results (Fig. 9, based upon data in Fig. 7) are only as accurate as the age class designations, which are somewhat arbitrary. At birth mean SVL is 31 mm and mean weight is 0.44 g; at one year, 39 mm and 0.89 g; at two years, 47 mm and 1.51 g; and by June of the third year, when lizards are approximately 32 months old, mean SVL is 51 mm and mean weight is 1.96 g.
Growth in X. h. henshawi, as in most vertebrates, is allometric (Figs. 10, 11). Relative to SVL, small lizards have short tails and long heads. A possible deviation from simple allometry is suggested in Figure 11. Lizards above 60 mm apparently have relatively shorter tails than lizards of intermediate sizes; possibly I failed to detect caudal autotomy in some of the larger lizards.
Contrary to the situation among turtles and crocodilians, some lizards exhibit determinate growth which results from fusion of the primary centers of ossification (diaphyses) with the secondary centers (epiphyses) of the endochondral bones (Haines, 1969). Such epiphysial-diaphysial union is illustrated for X. h. henshawi in Figure 12. Of 15 lizards examined by radiography, the smallest male showing such union was 52 mm SVL; the smallest female, 58 mm. These are close to the sizes at which I estimate reproductive maturity is attained. The approximately normal size distribution of adults from site 2 (Fig. 7) and the lack of extraordinarily large individuals also suggests determinant growth for this species.
Mortality. — Available life table data for X. h. henshawi are inadequate for calculation of mortality rates, but an approximation of mortality can be inferred from the relative abundance of age classes. Newborn lizards in the October sample from site 2 comprise 28 per cent of that month's sample. If the population is at equilibrium, annual mortality approximates 28 per cent. The abundance, in each sample, of lizards in the third year or older indicates that large numbers of lizards survive the first two years — convincing evidence that mortality is low.
In October, 1970, in the vicinity of Jamul, San Diego Co., lizards were collected in areas devastated two days previously by the Laguna Fire. Lizards were frequently removed from beneath flakes that had been blackened by fire, yet no dead or injured lizards were found, nor did lizards seem less abundant than in contiguous unburned situations. Samples from a burned area and an adjacent unburned area, collected approximately three months after the fire, showed little length-specific weight difference (Fig. 13),
267
First Year
Second Year
Third Year
E
E
0)
c
55-r
50-
45-
40-
C
% ^ 35
D O
c
30-
25-
7 8
8 6 6
11
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29
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16
B
|
9 |
15 |
16
H
0 N D J F
-I 1-
J J A S 0 N D J F
J JASONDJ FMAMJ
Time (months)
Figure 9. Growth rate in Xantusia henshawi henshawi during the first three years of life. For each sample, vertical line indicates range, horizontal line indicates mean. Rectangles encompass 95% confidence limits for the parametric means. Number above vertical line indicates sample size.
indicating that lizards from burned and unburned areas are equally well nourished.
No incidents of predation on X. h. henshawi were observed during this study, but potential predators (Table 2) were encountered frequently. Murray (1955) recorded a Sceloporus orcutti with the hind portion of a X. h. henshawi protruding from its mouth. Petrosaunis mearnsi eats X. h. henshawi in captivity (Cozens, pers. comm.); Petrosaurns is widely sympatric with X. h. henshawi, and occupies a similar microhabitat. In this study, Hypsiglena torquata was twice oberved at night resting about one and a half meters above ground between the leaves of a shrub and the side of a boulder. In both cases the snakes were within a meter of individual X. h. henshawi. In captivity this species readily devours X. h. henshawi, as do Masticophis lateralis, Trimorphodon vandenburghi, Salvadora hexalepis, and Lampropeltis getulus, all of which are sympatric with X. h. henshawi.
Potential diurnal avian predators include Falco sparverius, Buteo jamaicensis, Geococcyx califomianus, Aphelocoma coerulescens, and Corvus corax. Due to its secretive habits, X. h. henshawi probably rarely falls prey to these birds. Nocturnal birds such as Bubo virginianus, Tyto alba, and Otus asio may occasionally capture these lizards, but Xantusia are probably below the usual size range of prey items for the former two species.
Many rodents are omnivorous (Landry, 1970), and I consider Neotoma a potential predator, particularly because of its size, its propensity for rocky situations, and its nocturnality which undoubtedly brings it into contact with X. h. henshawi.
Caudal autotomy. — Like many lizards, X. h. henshawi can lose and subsequently regenerate portions of the tail. It is frequently assumed that regenerated tails can be distinguished on the basis of size, color, and scutellation. Yet, Zweifel and Lowe (1966) were sometimes unable to distinguish regenerated tails in Xantusia vigilis without the aid of radiographs. Of 15 X. h. henshawi examined in this study by radiography, however,
268
regeneration was invariably associated with one or more of the above criteria. Nonetheless, some autotomy may have gone undetected. Thus data concerning the frequency of autotomy are minimal estimates. Of 257 sexable lizards from site 2, 159 (61.4%) have experienced caudal autotomy at least once, with larger (presumably older) lizards showing the highest frequency (Fig. 14). The incidence of autotomy was the same in males (74 of 122, 60.0%) and females (85 of 135, 62.5%).
Reproduction. — Of 75 preserved males in the SDSNH, the smallest exhibiting testicular enlargement were 47 mm SVL. Because slight shrinkage occurs in preservative, I infer that sexual maturity in males is attained at about 50 mm SVL, when lizards are in their third year. Testicular volume varies considerably through the year (Table 3). Testicular volume is low during winter, maximizes in late spring and early summer, then apparently declines in late summer and fall.
TABLE 3. Seasonal variation in testicular volume in Xantusia henshawi henshawi. N indicates number of testes examined.
|
Month |
N |
X |
SD |
|
January |
13 |
3.83 |
2.17 |
|
March |
5 |
7.53 |
2.64 |
|
April |
10 |
17.01 |
10.49 |
|
May |
3 |
30.30 |
7.14 |
|
June |
5 |
19.49 |
7.61 |
|
July |
3 |
23.18 |
5.13 |
|
November |
2 |
11.20 |
0.01 |
The smallest gravid female I encountered was 56 mm SVL, suggesting that sexual maturity is attained at about that length. Moreover, females above 54 mm SVL undergo pronounced seasonal weight change, whereas those below 54 mm do not (Fig. 15). Above 54 mm, April-May females are significantly heavier than January females, and June females are significantly heavier than the April-May sample. By October weights have regressed to slightly below January levels. This weight change is probably the result of fat deposition necessary to carry gravid females through the hot dry period of gestation. Males do not exhibit this seasonal weight change. I therefore infer that females are sexually mature at about 54-56 mm SVL, a length attained late in the third, or early in the fourth year of life.
I observed attempted copulation among recently captured lizards on 18 June, 6 July, and 7 July. The attempts were similar to the general saurian pattern, and presumably reflected the timing of copulatory activity in the population from which they came. Thus breeding extends from at least mid June through early July.
Like other xantusiids, X. h. henshawi is viviparous. Parturition usually occurs from mid September through mid October. Parturition dates for 28 broods born to recently captured females spanned the period 17 September to 19 October, but a newborn lizard collected at site 2 on 3 September shows that parturition occasionally occurs earlier. Assuming that fertilization occurs shortly after copulation, gestation requires about 90 days.
Population structure, timing of seasonal weight increase, and timing of copulation and parturition indicate that females at site 2 produce one brood per year. Because most sexually mature females exhibit a pronounced weight increase in spring, I assume that females are able to breed each year.
Of 28 broods, 13 contained two offspring and 15 contained one (X = 1.46). For broods consisting of two offspring, a strong positive correlation exists between the SVL of the female and the combined weight of her offspring (r = 0.915, P< 0.01).
Thermal biology. — Sixty-eight cloacal temperatures ranging from 18.1 to 31.8 C were obtained from lizards abroad at night at site 2. Mean temperatures for males and females do not differ significantly (25.6 and 25.2 respectively). Cloacal temperatures are strongly
269
26-30 31-35 36-40 41 45 46-50 51-55 56-60 61-65 66-70
Snout-vent Length (mm) Figure 10. AUometric growth in the head of Xantusia henshawi henshawi. Symbols as in Figure 9.
correlated with both substrate and air temperatures (Figs. 16 and 17 respectively), but the higher coefficient of determination indicates that lizards are more closely coupled to substrate temperatures than to air temperatures.
DISCUSSION AND CONCLUSIONS
Sexual dimorphism. — Like many species of lizards, X. h. henshawi exhibits sexual size dimorphism, with females larger than males. Because larger female X. h. henshawi produce heavier, presumably more" fit offspring, this may be an adaptation to accommodate relatively large embryos.
Among lizards, sexual dichromatism is widespread and often assumed to have a social function. Dichromatism therefore implies color vision, and the absence of color vision should preclude the evolution of social sexual dichromatism. Xantusia vigilis and Klauberina riversiana possess retinas adapted to conditions of low light intensity (Walls, 1942), conditions under which visual information in terms of color would be difficult to perceive, and color vision would be unlikely to evolve. Both are sexually monochromatic. Similarly, the secretive crepuscular-nocturnal habits of X. h. henshawi suggest the absence of color vision and probably account for the monochromatism of this species.
Males of many species of lizards, including X. h. henshawi, possess enlarged femoral pores, whereas those of the females are rudimentary. Pores and their secretions may somehow be associated with sexual activity (Atland, 1941; Bellairs, 1970; Bostic, 1964; Cole, 1966), but in X. h. henshawi femoral pore secretion is first evident in males at a SVL of about 44 mm and thus preceeds the acquisition of sexual maturity.
Population structure. — Many investigators have found unbalanced sex ratios among reptiles (Fitch, 1961). Among lizards such deviations usually favor females and are interpreted as the result of differential predation acting against the more conspicuous territorial males. The expected 1:1 sex ratio in X. h. henshawi for all age classes indicates that no such differential mortality is operating on this species. This is reasonable, for in this secretive monochromatic species, males are no more conspicuous than females.
A remarkable feature of the age class structure of the X. h. henshawi population is the high proportion of adults, implying a low rate of turnover. In this X. h. henshawi is similar to Xantusia vigilis in which 51 per cent of a winter population consisted of mature
270
26-30 31-35 36-40 41-45 46-50 51-55 56-60 61-65 66-70
Snout-vent Length (mm)
Figure 1 1 . Allometric growth in the tail of Xantusia henshawi henshawi. Symbols as in Figure 9.
individuals (Zweifel and Lowe, 1966). Such age class structure is not unique to Xantusia, but it is in sharp contrast with the situation in many iguanids where high reproductive potential and high mortality combine to produce populations in which rates of turnover are high and immature lizards are abundant relative to adults. The iguanid lizard Uta stansburiana in west Texas is an extreme example in which life expectancy is little more than a year, and annual turnover approaches 100 per cent (Tinkle, 1965).
For X. h. henshawi, a species of narrow ecological tolerance, limited geographical distribution, existing in an area of low and unpredictable rainfall, a high proportion of long-lived breeding adults is adaptive in that it permits the population to survive several successive seasons of reproductive failure. The probability of such failure may be high, for the correlation between reproductive failure and inadequate mositure has been
B
Figure 12. Epiphyseal-diaphyseal fusion in the humerus oi Xantusia henshawi henshawi. A. 46 mm SVL B. 49 mm SVL C. 62 mm SVL.
271
|
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H 1 1 h
H 1 h
45
50 5 5 60
Snout-vent Length (mm)
H — I — h-
65
Figure 13. Comparison of the relationship between weight and snout-vent length in samples of Xantusia henshawi henshawi from burned (solid circles) and unbumed (open circles) areas.
documented for some lizards (Mayhew, 1965; Nagy, 1973), including X vigilis (Zweifel and Lowe, 1966).
Growth. — For its size, X. h. henshawi is an unusually slow growing, late maturing species; males first breed at about two and a half years, females at three and a half years. In this respect X. h. henshawi is identical to X vigilis (Miller, 1951).
Like most vertebrates, X. h. henshawi has a relatively larger head at birth than at adulthood. This presumably results from the concentration of sense organs and nerve tissue in that area. Once ossified, the numerous complex, interlocking cranial elements preclude very much expansion in the head region. The biological significance of allometric growth in tail length of X. h. henshawi is obscure. It might reflect an ontogenetic change in the importance of the tail as an organ for fat storage, or changing demands on the tail as an organ of balance during locomotion. Fitch (1954) found similar allometric growth in the tail of the skink, Eumeces fasciatus.
Mortality. — Available evidence indicates that in X. h. henshawi mortality from all causes is low, as it must be for a species with low reproductive potential. This is so despite the fact that coexisting with X. h. henshawi are numerous potential ,predators. These lizards are probably most vulnerable when abroad at night, but their light nocturnal color phase closely approximates their granitic background, rendering them difficult to detect visually. Hypsiglena torquata and Trimorphodon vandenburghi, both nocturnal, perhaps occasionally prey on X. h. henshawi, but since neither species is numerous they may not make serious inroads in the lizard population. Nonetheless, the precise background matching coloration indicates that selection in the form of visually oriented predation has been a significant factor in the ecology of this species.
Brush fires might be a source of mortality in X. h. henshawi, as suggested by Klauber (1939). His conclusion that X. h. henshawi, in contrast to Uta and Sceloporus, was little affected by fires agrees with my observations that these lizards not only survive fires, but remain well nourished after living several months in a burned area.
Most chaparral fires in southern California occur during late summer and early fall during periods of high temperature, a time when X. h. henshawi seeks refuge deep within rock crevices from unfavorable temperatures. So situated, they are protected from fires
272
5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
Per Cent With Regeneration
Figure 14. Frequency of caudal autotomy in Xantusia henshawi henshawi by size class. Numbers inside bars indicate sample size.
which, although generating high temperatures, are of short duration.
Because the presence of granitic exfoliations is important for the existance of this species, fires, rather than being detrimental, may be an asset; the rapid expansion of boulders caused by the heat of brush fires accelerates exfoliation, thereby generating more habitat.
I have no evidence that food shortage contributes to mortality in post-partum lizards, although it might lower reprodutive success. Of 735 lizards collected in this investigation, only two were obviously malnourished; this could have been the result of pathology unrelated to the availability of food.
Of those species which are potential competitors for food (Table 2), most are either temporally or spatially separated from X. h. henshawi. Coleonyx, Phyllodactylus, Urosaurus, Uta, Sceloponis, and Petrosaurus are likely to share the same boulder-crevice microhabitat, but only the activity of the first two overlaps both temporally and spatially with that of X h. henshawi, which tend to be active within crevices during late afternoon and early evening and quiescent while abroad on boulders at night (Lee, 1974). In the area of sympatry between X. h. henshawi and Coleonyx, the latter is nowhere numerous, and Phyllodactylus overlaps X. h. henshawi geographically only on the desert slopes of mountains. Thus, although potential competitors for food are numerous, actual interspecific competition — if in fact food is limiting — is rare.
Caudal autotomy. — A high frequency of caudal autotomy suggests heavy predation pressure, but such a conclusion is inconsistent with the ecology of X. h. henshawi, for actual predator species are few, and individuals never abundant. Observations by Heimlich and Heimlich (1947), Lowe (1948), and Brattstrom (1952) provide an alternative explanation. Both Heimlich and Heimlich, and Brattstrom found tails of conspecifics in the stomachs of Xantusia vigilis; Lowe reported agonistic interactions among captive X. vigilis involving biting; and Zweifel and Lowe (1966) concluded that intraspecific fighting accounted for most of the autotomy observed by them during their nine year study of X. vigilis in the Mojave Desert. My observations on captive X. h. henshawi agree closely with those of Lowe (1948) for X. vigilis. Among captive X. h. henshawi, fights were common and involved twitching of the tail and biting, with the bites often directed toward the base of the tail. Several lizards exhibiting recent autotomy undoubtedly lost their tails in this manner. The high incidence of caudal autotomy in X. h. henshawi probably is more a reflection of intraspecific fighting than a high rate of attempted predation.
273
6.0
5.5
5.0
4.5
4.0 1 r 3.5
i
3.0 +
2.5
2.0
1.5
• April-May
o June
A October
▲ January
^-^-^ /^A A A A ^
^A
— I — I— I — till 1 — I 1 — I — I 1 1 — I — I — I — I — I 1— I — I — I—" — I —
44 46 48 50 52 54 56 58 60 62 64 66 68
Snout-vent Length (mm)
Figure 15. Relationship between weight and snout-vent length for female Xarttusia henshawi henshawi collected at different times of the year. Below 54 mm 95% confidence limits for all regressions broadly overlap. Above 61 mm confidence limits for January entirely overlap October and slightly overlap April-May.
Reproduction. — Mean brood size for X h. henshawi is lower than that reported for
Xantusia vigilis by Zweifel and Lowe (1966) (L46 and L87 respectively). Because female
X. h. henshawi probably require three years to reach reproductive maturity, produce only
a single brood per season, and average L46 offspring per brood, this species has the
lowest reproductive potential (in the sense of Ballinger, 1973) reported for any lizard.
However, the difference in brood size between X. h. henshawi and X. vigilis may not be
significant, because Zweifel and Lowe (1966) demonstrated a strong positive correlation
between brood size and amount of winter precipitation. If a similar relationship exists for
X. h. henshawi. my estimate of brood size, based upon lizards collected in 1972, is a
minimal one. Precipitation for the winter of 1971-72 in San Diego Co. was well below
normal.
The low reproductive potential of X. h. henshawi may be contrasted with that of
Sceloporus olivaceous, a species with perhaps the highest known reproductive potential of
274
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ROCK SURFACE TEMPERATURE
AIR TEMPERATURE C
Figure 16. Regression of cloacal temperature of Figure 17. Regression of cloacal temperature of
Xantusia henshawi henshawi against rock surface XaMfus/a AeniAawj AensAam against air temperature,
temperature.
any lizard. In that species, yearling females may produce four clutches of eggs per season with a mean clutch size of 11.3 eggs. Clutch size increases to 18.4 in two-year-olds, and 24.5 in lizards three years of age (Blair, 1960). Theoretically, a female Sceloporus olivaceous surviving through the third breeding season could produce about 217 offspring in the time it would take X. h. henshawi to produce one or two. Mortality, of course, is very different in these two species. An average of 75 per cent of Sceloporus olivaceous eggs fail to hatch, and mean life expectancy at hatching is about three months (Blair, 1960). In the viviparous X. h. henshawi, developing embryos are protected, reducing mortality during development, and post-partum mortality is low, allowing females a protracted breeding life.
On the basis of reproductive strategy and attendant life history characteristics, Tinkle (1969) and Tinkle et al. (1970) have identified two categories of lizards. One contains small species that are early-maturing, short-lived, and highly fecund (e.g., Sceloporus olivaceous); the other contains larger species that are late-maturing, have long life expectancy, and produce few offspring per season. Members of the former category are relatively r-selected (Pianka, 1970); they allocate large amounts of energy for reproduction, produce many offspring, but apportion little energy per individual offspring. Members of the latter category are relatively A'-selected, channeling energy into production of a few highly fit offspring. Except for size, X. h. henshawi typifies the latter category and is a highly AT-selected species.
Thermal biology. — In previous studies dealing with the thermal biology of X. h. henshawi (Brattstrom 1965; Mautz and Case, 1974; Scott, 1971) cloacal temperatures obtained from lizards in the field were apparently taken only during daylight hours, and from lizards that had been removed from crevices. In the present study, cloacal temperatures obtained at night from lizards abroad on boulders indicate that X. h. henshawi is highly dependent on rock surface temperatures; thus, Brattstrom's (1965) designation of this species as a thigmotherm is appropriate.
Cowles and Bogert (1944) define the normal activity range of temperatures in reptiles as ". . . the thermal range extending from the resumption of ordinary routine (after the animal has ceased basking, in the case of diurnal forms) and terminates at a point just below the level at which high temperatures drive the animal to shelter." Elsewhere (Lee, 1974) I show that maximum activity in this species occurs before lizards issue forth from their crevices at night. Therefore, the range of temperatures recorded for these lizards abroad at night may not reflect the normal activity range, but rather the range over which a relatively quiescent portion of the activity cycle occurs. Thus, my data cannot be directly
275
compared with published data on normal activity ranges of lizards. It is of interest, however, to compare them with the range of temperatures tolerated voluntarily during the day as determined by Scott (1971). The close correspondence between Scott's data (18.6 to 33.0 C, X = 26.0) and mine (18.1 to 31.8 C, X = 25.3) indicates that in general, during the warmer part of the year, lizards maintain body temperatures within about the same limits both day and night. This species is clearly eurythermic, tolerating a wide range of body temperatures and with no clearly defined preferred temperature.
The biology of Xantusia henshawi compared with that of other xantusiids. — The Xantusiidae are a small, apparently ancient family of unknown origin (Bezy, 1972). Savage (1963) recognized four living genera: Cricosaura, monotypic and known only from Cabo Cruz, Oriente Province, Cuba; Klauberina, also monotypic and restricted to the Channel Islands off the coast of southern California; Lepidophyma, with perhaps 12 species, confined to southern Mexico and Central America; and Xantusia, with two species, restricted to northeastern Mexico and the southwestern United States.
Ecologically, the family is relatively homogeneous. Xantusiids tend to be small, secretive, and terrestrial. So far as known, all are viviparous and most have low reproductive potential (Goldberg and Bezy, 1974). As a group they are relatively AT-selected. Xantusia henshawi henshawi and Xantusia vigilis are especially similar in reproductive biology, population structure, growth (Miller, 1951), and thermal biology (Kour and Hutchinson, 1970).
Xantusiids exhibit highly disjunct, frequently relictual distributions, and often have specialized microhabitat requirements (rock crevices, fallen yuccas, decomposing logs in humid tropical forests). Bezy (1972) views this as a response to increasing aridity during the Tertiary. Perhaps an additional factor has been competition with other lizards. If xantusiids are competitively inferior, the few existing species are those that have survived the Tertiary radiations of other lizard groups by avoiding competition, either by increased specialization (e.g., Xantusia henshawi henshawi) or by fortuitous establishment on (or restriction to) islands (e.g., Klauberina).
ACKNOWLEDGEMENTS
Roger Carpenter, Richard Etheridge, and Paul Nichols critically reviewed portions of the manuscript. Michael U. Evans took the photographs which appear as Figures 3 and 6. Janet Lee provided financial support for this study. This report is a portion of a thesis submitted to the faculty of San Diego State University in partial fulfillment of the requirements for the degree of Master of Science.
LITERATURE CITED
Atland, P.D.
1941. Annual reproductive cycle of the male fence lizard. J. Elisha Mitchell Sci. Soc. 57:73-83. Atsatt, S.R.
1925. Observations on \\\\ng Xantusia henshawi. Copeia 1925:71-72. Atsatt, S.R.
1939. Color changes controlled by temperature and light in the lizards of the desert regions of southern California. Univ. California (Los Angeles) Pub. Biol. Sci. 1:237-276. Ballinger. R.B.
1973. Comparative demography of two viviparous iguanid lizards (Sceloporus jarrovi and Sceloporus poinsetti). Ecology 54:269-283. Bellairs, A.
1970. The life of reptiles. 2 vols. Universe Books, New York. 590 p. Bezy, R.L.
1972. Karyotypic variation and evolution of the lizards of the family Xantusiidae. Los Angeles Co. Mus. Nat. Hist., Contrib. Sci. 227:1-29. Blair, F.W.
1960. The rusty lizard. University of Texas Press, Austin. 185 p.
276
Bostic. D.L.
1964. The ecology and behavior oi Cnemidophorus hyperythrus beldingi (Sauria: Teiidae). Master's thesis, San Diego State University. 112 p. *
Brattstrom. B.H.
1951. The number of young of Xantusia. Herpetologica 7:143-144.
Brattstrom, B.H.
1952. The food of the night lizards, genus Xantusia. Copeia 1952:168-172. Brattstrom, B.H.
1965. Body temperatures of reptiles. Am. Midi. Nat. 73:376-422. Cole, C.
1966. Femoral glands in lizards: a review. Herpetologica 22:199-206. Cowles, R.B. and CM. Bogert.
1944. A preliminary survey of the thermal requirements of desert reptiles. Am. Mus. Nat. Hist., Bull. 83:265-296. Etheridge, R.
1962. Skeletal variation in the iguanid lizard Sator grandaevus. Copeia 1%2:613-619. Fitch, H.S.
1954. Life history and ecology of the five-lined skink, Eumeces fasciatus. Univ. Kansas Publ. Mus. Nat. Hist. 8:1-156.
Fitch, H.S.
1961. Longevity and age-size group in some commons snakes. In: Vertebrate speciation, a University of Texas symposium. University of Texas Press, Austin. Fitch, H.S.
1970. Reproductive cycles in lizards and snakes. Univ. Kansas Mus. Nat. Hist., Misc. Publ. 52:1-247. Goldberg, S.R. and R.L. Bezy.
1974. Reproduction in the island night lizard, Xantusia riversiana. Herpetologica 30:350-360. Grinnell, J. and C.L. Camp.
1917. A distributional list of the amphibians and reptiles of California. Univ. California Publ. Zool. 17:127-208. Haines, R.W.
1969. Epiphyses and sesamoids. In: Cans, C, Bellairs, A., and T.S. Parsons (eds.). Biology of the Reptilia. vol. 1. Academic Press, New York. 373 p.
Heimlich, E.M. and M.G. Heimlich.
1947. A case of cannibalism in captive Xantusia vigilis. Herpetologica 3:149-150. Klauber, L.M.
1926. Field notes on Xantusia henshawi. Copeia 1926:115-117. Klauber, L.M.
1931. A new species of Xantusia from Arizona, with a synopsis of the genus. San Diego Soc. Nat. Hist., Trans. 7:1-16. Klauber, L.M.
1939. Studies of reptile life in the arid southwest. Zool. Soc. San Diego, Bull. 15:1-23. Kour, E.L. and V.H. Hutchison.
1970. Critical thermal tolerances and cooling rates of lizards from diverse habitats. Copeia 1970:219-229. Landry, S.O.
1970. The rodentia as omnivores. Quart. Rev. Biol. 45:351-372. Lee, J.C.
1974. The diel activity cycle of the lizard, Xantusia henshawi. Copeia 1974:934-940. Lowe, C.H.
1948. Territorial behavior in Xantusia vigilis. Herpetologica 4:221-222. Mautz, J. and T.J. Case.
1974. A diurnal activity cycle in the granite night lizard, Xantusia henshawi. Copeia 1974:243-251. Mayhew, W.W.
1965. Comparative reproduction in three species of the genus Uma. In: W.W. Milstead (ed.). Lizard ecology, a symposium. University of Missouri Press, Columbia. 300 p. Miller, M.
1951. Some aspects of the life history of the yucca night lizard, Xantusia vigilis. Copeia 1951:114-120. Murray, K.F.
1955. Herpetological collections from Baja California. Herpetologica 11:33-48. Nagy, K.A.
1973. Behavior, diet, and reproduction in a desert lizard, Sauromalus obesus. Copeia 1973:93-102. Pianka, E.R.
1970. On rand A" selection. Am. Nat. 104:592-597. Savage, J.M.
1963. Studies on the lizard family Xantusiidae. IV. The genera. Los Angeles Co. Mus. Nat. Hist., Contrib. Sci. 71:1-38.
277
Scott, R.
1971. Thermal biology of the granite night lizard. Master's thesis, San Diego State University. Shaw, C.E.
1949. Notes on broods of two xantudiids. Herpetologica 5:23-26. Stebbins, R.C.
1954. Amphibians and reptiles of western North America. McGraw-Hill Book Co. Inc., New York. 536 p. Stebbins, R.C.
1966. A field guide to western reptiles and amphibians. Houghton Mifflin Co., Boston. 279 p. Stejneger, L. and T. Barbour.
1943. Checklist of North American amphibians and reptiles. 5th ed. Mus. Comp. Zool., Bull. 93(1): 1-260. Stephens, F.
1921. An annotated list of the amphibians and reptiles of San Diego County, California. San Diego Soc. Nat. Hist., Trans. 3:57-69. Tinkle, D.
1965. Home range, density, dynamics, and structure of a Texas population of the lizard Uta stansburiana. In: W.W. Milstead (ed.) Lizard ecology, a symposium. University of Missouri Press, Columbia. 300 p.
Tinkle, D.
1969. The concept of reproductive effort and its relation to the evolution of life histories of lizards. Am. Nat. 103:501-516.
Tinkle, D., Wilber, H.M. and S.G. Tilley.
1970. Evolutionary strategies in lizard reproduction. Evolution 24:55-74. Walls, G.
1942. The vertebrate eye and its adaptive radiation. Cranbrook Inst. Sci. 785 p. Webb, R.
1970. Another new night lizard {Xantusia) from Durango, Mexico. Los Angeles Co. Mus. Nat. Hist., Contrib. Sci. 194:1-10. Zweifel, R. and C. Lowe.
1966. The ecology of a population oiXantusia vigilis, the desert night lizard. Am. Mus. Novitates 2247:1-57.
San Diego State University, San Diego, California. Present address: Museum of Natural History and Department of Systematics and Ecology, University of Kansas, Lawrence, Kansas 66045.
S/W Gqc^^
AU6 1 9 1970
HARVAWO
TRAN
OF THE
SOCIETY OF p NATURAL hist'
IONS
VOL. 17, NO. 20 16 MAY 1975
A CAT'
p. 2
p.i
r
p. i
p. i
A CATALOGUE OF MURICACEAN GENERIC TAXA
ERRATA
p. 279, last line - should read — monotypy; ^ -extinct genus p, 281, right column, immediately after line 52 insert —
CYMIA Morch, 1860: 97, 98 Type sp. (M.)' Cuma sulcata Swainson, 1340, A Treatise on Malacology, p. 87, fig. 4 (= Buccinum tectum Wood, 1828) p, 283, right column, line 34 - should read — LYROTYPHIS. p. 234. left column, line 35 — delete whole line
left column, line 44 — acute accent over "e" in Linne. right column, line 59 — "Jousseaume" instead of ''Jousseaum". p. 286, left column, line 43 — should read ~ lieth. pi. 436, fig. 1,
Liste, p. 8. right column, line 1 — should read — figs, la, lb, Liste, p. 1. right column, line 10 ~ "non-biononinal" should be - "non-binominal'' p. 288, right column, line 53 — "Collected" should begin with a lower
case letter, p. 289, right column, line 59 — "recent" should begin with an upper case
letter.
SAN DIEGO SOC. NAT. HIST., TRANS. 17(20): 279-292, 16 MAY 1975.
A CATALOGUE OF MURICACEAN GENERIC TAXA
GEORGE E. RADWIN AND ANTHONY D'ATTILIO
ABSTRACT. — A compilation of genus-level taxa and their type-species is provided, including the mode of type designation and references to the original descriptions of the genera and the type-species.
Despite long-standing and recently intensified interest in muricacean mollusks, no compilation of generic taxa is currently available. The most complete listing (Wenz, 1941) lacks the depth needed by taxonomists and other workers. Wenz listed only 223 taxa and he treats half of these as synonyms, for which he does not supply type-species; where he does note type-species he rarely cites the mode of type designation or gives references to these type-species. Yokes (1971) presented a more complete listing, at the species level, for several subfamilies of the Muricidae, and Keen (1944) catalogued the Typhinae at the specific and generic levels.
In preparing a guide to the Muricidae, we compiled nomenclatural data on genera in that and other muricacean families. They are catalogued below. In the first section we list nominal generic and subgeneric muricacean taxa, most cited from primary sources, arranged alphabetically, including type-species designations and original references. The list is essentially complete through 1974. In the second section we present a bibliography of works in which muricacean generic taxa have been introduced. We have supplied complete citations to generic references, abbreviated references of type-species and subsequent type designations. As this catalogue is intended to serve as a reference work, rather than as a vehicle for our taxonomic opinions, we have avoided all but the most essential comments on synonymy. The following abbreviations are used: O, D. — type species by original designation; S. D. — type species by subsequent designation; M. — type species by monotypy; T. — type species by tautonymy; S. M. — type species by subsequent monotypy; — extinct genus.
SAN DIEGO SOC. NAT. HIST., TRANS. 17(20): 279-292, 16 MAY 1975.
280
GENERIC AND SUBGENERIC TAXA OF THE MURICACEA
AARONIA A. H. Verrill, 1950: 4
Type sp. (O. D.): Murex (Aaronia) strausi Verrill, 1950, Min. Conch. Club S. California 103: 4.
ACANTHINA Fischer de Waldheim, 1807: 174 Type sp. (S. D., Gray, 1847b): Buccinum mono- cerus Chemnitz, 1788 (= Buccinum monodon Pallas, 1774). Neues Systematisches Conchylien- Cabinet 10: 197, pi. 154, figs. 1469, 1470).
tACANTHlNELLA Shuto, 1969: 109
Type sp. (O. D.): Acantina (sic.) _/ava«a Martin, 1899, Samml. Geol. Mus. Leiden, N. F. 1: 109.
ACANTHINUCELLA Cooke, 1918: 8
Type sp. (O. D.): Acanthina punctulata (Sowerby, 1835), Proc. Zool. Soc. London 3: 50.
tACANTHOLABIA Olsson & Harbison. 1953: 252 Type sp. (O. D.): Acantholabia floridana Olsson & Harbison, 1953, Acad. Nat. Sci. Phila. Monogr. 8: 251. pi. 33, fig. 10.
ACANTHOTROPHON Hertlein & Strong, 1951: 86 Type sp. (O. D.): Trophon (Acanthotrophon) sorensoni Hertlein & Strong. 1951, pt. X. Zoo- logica 36(2): 86, p. 2. fig. 1.
ACTINOTROPHON Dall, 1902: 534
Type sp. (M.): Trophon (Boreotrophon) actino- phorus Dall, 1889. Mus. Comp. Zool. Harvard 18: 206.
ACUPURPURA Jousseaume, 1880: 335
Type sp. (O. D.): Murex tenuispina Lam., 1822, (= M. pecten Lightfoot, 1786) Hist. Nat. Anim. s. Vert. 7: 158.
ADAMSIA Dunker, 1857: 357 (Not Forbes, 1840) Type sp. (O. D.): Adamsia typica Dunker, 1857 (= Purpura tritonifonnis Blainville, 1832), Proc. Zool. Soc. London 25: 357.
AFRITROPHON Tomlin, 1947: 271
Type sp. (O. D.): Trophon kowieensis Sowerby. 1901, Proc. Malac. Soc. London 4: 213. pi. 22. fig. 16.
AGNEWIA Tenison-Woods, 1878: 29
New name for Adamsia Dunker, 1857. not Forbes 1840.
tALDRICHIA K. Palmer. 1937: 262
Type sp. (O. D.): Murex cancellaroides Meyer & Aldrich, 1886 (= Muricopsis aldrichi Cossmann, 1903, new name for M. cancellaroides Meyer & Aldrich, 1886, not Grateloup, 1833), J. Cinn. Soc. Nat. Hist. 9: 44, pi. 2 fig. 15.
ALIPURPURA P. Fischer, 1884: 641
Type sp. (O. D.): Murex acanthopterus Lamarck, 1822, Hist. Nat. Anim. s. Vert. 7: 165.
ANATROPHON Iredale. 1929a: 186
Type sp. (O. D.): Trophon sarmentosa Hedley & May, 1908, Rec. Australian Mus. 7: 121.
ANTIMUREX Cossmann, 1903: 12
New name for Crassilabrum Jousseaume, 1880. not Megerle von Muhifeid (Ms) in Scudder, 1882. (This unnecessary replacement name was intro- duced by Cossmann on the assumption that Megerle's manuscript genus Crassilabrum pre- occupied Crassilabrum Jousseaume. In actuality Megerle's (Ms) name was not validated until Scudder (1882), thus making it junior to Jous- seaume's taxon.)
APIXYSTUS Iredale, 1929a: 185
Type sp. (O. D.): Trophon stimuleus Hedley. 1907, Rec. Australian Mus. 6: 293, pi. 55, fig. 19.
ARADOMUREX Coen, 1929: 1281
Type sp. (O. D.): Murex sophiae Aradas & Benoit.
1870, Conch. Viv. Mar. Sicil. p. 270-271, pi. 5,
fig. 7. ARANEA Perry, 1810: 225 (not /lra«ea Linne, 1758)
Type sp. (M.): Aranea gracilis Perry, 1810, The
Arcana, p. 225, pi. 47. ASPELLA Morch. 1877: 24
Type sp. (M.): Ranella anceps Lamarck, 1822,
Hist. Nat. Anim. s. Vert. 7: 154. ATTILIOSA Emerson. 1968a: 380
Type sp. (O. D.): Coralliophila incompta Berry,
1960, Leaflets in Malacology 1(19): 119-120. AUSTROTROPHON Dall, 1902: 534. 548
Type sp. (S. D. Grant & Gale. 1931): Trophon
cerrosensis Dall. 1891, Proc. U. S. Natl. Mus. 14:
181, pi. 5, figs. 5. 7. AXYMENE Finlay. 1927: 426
Type sp. (O. D.): Trophon (A.) turbator Finlay.
1927, Trans. Proc. New Zealand Inst. 57: 426, pi.
23. figs. 127. 128. AZUMAMORULA Emerson. 1968b: 380
New name for Morulina Dall, 1923. not Borner.
1906. BABELOMUREX Coen. 1922: 68
Type sp. (O. D.): Fusus babelis Requien, 1848,
Cat. des Coquilles de Tile de Corse, pt. 49 p. 76,
sp. 549. BASSIA Jousseaume, 1880: 335 (not Quoy & Gaimard, 1830)
Type sp. (O. D.): Murex stainforthi Reeve, 1842,
Proc. Zool. Soc. London 9: 104. BASSIELLA Wenz, 1941: 1089
New name for Bassia Jousseaume. 1880. not Quoy
& Gaimard. 1830. BATHYMUREX Clench & Perez Farfante. 1945: 41
Type sp. (O. D.): Bathymurex atlantis Clench &
Perez Farfante. 1945. Johnsonia 17: 41, pi. 21,
figs. 3-5. BEDEVA Iredale. 1924: 183
Type sp. (O. D.): Trophon hanleyi Angas. 1867
(= Trophon paivae Crosse. 1864). Proc. Zool.
Soc. London 31: 110, pi. 13, fig. 1. BEDEVINA Habe, 1946: 198
Type sp. (O. D.): Trophon birilefft Lischke. 1871,
Malak. Bi. 18: 39. BENTHOXYSTUS Iredale. 1929a: 185
Type sp. (O. D.): Trophon columnarius Hedley &
May, 1908. Rec. Australian Mus. 7: 121, pi. 24,
fig. 22. BIZETIELLA Radwin & D'Attilio. 1972: 341
Type sp. (O. D.): Tritonalia carmen Lowe, 1935.
Trans. San Diego Soc. Nat. Hist. 8(6): 20. pi. 2
fig. 6. BOLINUS Pusch. 1837: 134
Type sp. (O. D.): Murex brandaris Linne, 1758,
Syst. Nat., Ed. 10, p. 747, no. 446. BOREOTROPHON P. Fischer. 1884: 640
Type sp. (M.): Murex clathrata Linne, 1767, Syst.
Nat., Ed. 12, p. 1223, no. 563. BRONTA Pusch, 1837: 130
New name for Brontes Montfort, 1810, not
Fabricius, 1801. BRONTES Montfort, 1810: 623 (not Fabricius, 1801)
Type sp. (O. D.): Brontes haustellum Montfort,
281
1810. (— Murex haustellum Linne, 1758) Conch. Syst. 2: 623. pi. 622.
BRONTESIA Reichenbach. 1828: 91
New name for Brontes Montfort, 1810, not Fabricius, 1801.
CALCITRAPESSA Berry, 1959: 13
Type sp. (O. D.): Murex leeamis Dall, 1890, Proc. U. S. Nat. Mus. 12: 329, pi. 7, fig. 1.
CALOTROPHON Hertlein and Strong, 1951: 87 Type sp. (M.): Calotrophon bristolae Hertlein & Strong. 1951 (= Tritonalia turrita Dall, 1919), Zoologica 36(2): 87, pi. 2. fig. 2.
CANRENA Link, 1807: 126
Type sp. (O. D.): Murex neritoideus Gmelin, 1791, Syst. Nat. Ed. 13, p. 3537, no. 43.
CARIBIELLA Perrilliat, 1972: 82
Type sp. (O. D.): Murex intermedius C. B. Adams, 1850, Contrib. to Conch. 1(4): 60.
CENTRIFUGA Grant and Gale, 1931: 706-707 Type sp. (O. D.): Murex centrifuga Hinds, 1844, Mollusca, pi. 1, p. 8, pi. 3, figs. 7, 8.
CENTRONOTUS Swainson, 1833: 100 (not Centronotus Schneider 1801) Type sp. (O. D.): Murex eurystomus Swainson, 1833 (= ?M. duplex Roding, 1798), Zool. Illust. (2)3: 100, pi. 3.
Type sp. (S. D., ICZN, 1970): Murex radix Gmelin, 1791, Syst. Nat., Ed. 13, p. 3527. (see ICZN opinion 911, 1970, Bull. Zool. Nomencl. 27: 20, wherein M. radix was designated as type to supersede all others).
CERASTOMA Conrad, 1837: 264 Type sp. (M.): Murex (Cerastoma) nuttalli, Con- rad. 1837: J. Acad. Nat. Sci. Philadelphia 7: 264, pi. 20, fig. 22.
CERATOSTOMA Hermannsen, 1846: 206
New name for Cerastoma Conrad, 1837, not Latreille, 1802.
CHALMON de Gregorio. 1885: 28
Type sp. (O. D.): Trophon (Chalmon) muricatus Montagu, 1802, Test. Brit. 1: 262. pi. 9, fig. 2.
CHATHAMIDEA Dell, 1956: 118
Type sp. (O. D.): C. expeditionis Dell, 1956, Dominion Mus. Bull. 18: 118, figs. 159, 160.
CHICOMUREX Arakawa, 1964: 361
Type sp. (O. D.): Murex superbus Sowerby, 1889, Proc. Zool. Soc. London 1889: 565, pi. 28, figs. 10, 11.
CHICOREUS Montfort, 1810: 610
Type sp. (fixed by ICZN opin. 911. 1970. Bull. Zool. Nomencl. 27: 20): Murex ramosus Linne, 1758, Syst. Nat. Ed. 10, p. 747, no. 448.
CHOREOTYPHIS Iredale, 1936: 324
Type sp. (O. D.): Typhina pavlova Iredale, 1936, Rec. Australian Mus. 19(5): 324, pi. 24, fig. 12.
CHORUS Gray, 1847b: 136
Type sp. (O. D.): Monoceros giganteus Lesson, 1831, Zool. 11(1): 403.
CINCLIDOTYPHIS DuShane, 1969: 343
Type sp. (O. D.): C. myrae DuShane, 1969, The Veliger, 11(4): 343. p. 54, figs. 1-3.
COLUMBARIUM von Martens, 1881: 105
Type sp. (O. D.): Pleurotoma (Columbarium) spinicitictum Martens, 1881; Conchologische Mitteilungen, 2: 105, pi. 21, fig. 1-4.
COLUZEA Finlay 1927: 407
Type sp. (O. D.): Fusus spiralis A. Adams, 1856, Proc. Zool. Soc. London 23: 221. (For comments see Keen, A. M., 1969, Bull. Zool. Nomencl.
26: 184.)
COMPTELLA Finlay, 1927: 424
Type sp. (O. D.): Trophon curtus Murdoch, 1905, Trans. New Zealand Inst. 37: 228.
CONCHOLEPAS "Klein" Bruguiere. 1792: 535 Type sp. (S. D. Lamarck, 1801): Concholepas peruvianus Lamarck, 1801 (= Buccinum con- cholepas Bruguiere, 1789), Syst. Anim. s. Vert, p. 70.
CONCHOPATELLA Herrmannsen. 1847: 291 Listed as synonym of Concholepas Lamarck, 1801 (= Concholepas Bruguiere, 1792).
CONCHULUS Rafinesque. 1815: 142
Introduced as a synonym oi Concholepas Lamarck, 1801 (= Concholepas Bruguiere, 1792).
CONOTHAIS Kuroda, 1930: 1
Type sp. (M.): Conothais citrina Kuroda, 1930, Venus, 2(1): 1.
CORALLINIA Bucquoy & Dautzenberg (in, Buc- quoy, Dautzenberg, & DoUfus), 1882: 24 Type sp. (O. D.): Murex aciculatus Lamarck, 1822, Hist. Nat. Anim. s. Vert. 7: 176.
CORALLIOBIA H. & A. Adams, 1853: 138
Type sp. (M.): Leptoconchus (Coralliobia) fimbriata H. & A. Adams, 1853 (nomen nudem) (= Concholepas [Coralliobia] fimbriata A. Adams, 1854), Proc. Zool. Soc. London 19: 93.
CORALLIOFUSUS Kuroda, 1953: 119
Type sp. (O. D.): Coralliofusus acus Kuroda, 1953, Venus 17: 119, figs. 3. 4.
CORALLIOPHILA H. & A. Adams, 1853: 135 Type sp. (S. D. Iredale, 1912): Murex neritoideus Chemnitz (non-binominal) (= Fusus neritoideus Lamarck, 1816), Neues Systematisches Con- chylien-Cabinet 10: 280, pi. 165, figs. 1577, 1578.
CRASPEDOTRITON Dall, 1904: 119
Type sp. (O. D.): Triton convolutus Broderip,
1833, Proc. Zool. Soc. London 1: 7. CRASSILABRUM Jousseaume. 1880: 335
Type sp. (O. D.): Murex crassilabrum Sowerby,
1834. Conch. Illust. Murex. pi. 59, fig. 14. CRONIA H. & A. Adams, 1853: 128
Type sp. (M.): Purpura amygdala Kiener, 1835, Spec. Gen. Icon. Coq. Viv. . . . Pourpre, p. 39, pi. 10, fig. 26.
CUMA Swainson, 1840: 87, 307
Type sp. (O. D.): Buccinum tectum Wood, 1828, Index Testaceologicus ... A catalog of shells, Suppl. p. 12, no. 13, pi. 4, fig. 13.
CUMOPSIS Rovereto, 1899: 105
New name for Cuma Swainson, 1840, not Milne- Edwards, 1828-see Cymia Morch, 1860.
CYTHAROMORULA Kuroda, 1953: 183
Type sp. (M.): Cytharomorula vexillum Kuroda, 1953, Venus 17: 183.
DALLIMUREX Rehder, 1946: 142
Type sp. (O. D.): Murex nuttingi Dall, 1896 ( = Murex paz/ Crosse, 1869), Bull. Lab. Nat. Hist., State Univ. Iowa 4(1): 13, pi. 1, fig. 1.
DENTOCENEBRA Monterosato, 1917: 21
Type sp. (O. D.): Ocenebra corallinus Scacchi, 1836 (= O. aciculata Lamarck, 1822), Cat. Conch. Regni Neap., p. 11, fig. 15.
DERMOMUREX Monterosato, 1890: 181
New name for Poweria Monterosato, 1884, not Bonaparte, 1841.
DICATHAIS Iredale, 1936: 325
Type sp. (O. D.): Buccinum orbita Gmelin, 1791, Syst. Nat. Ed. 13, Vermes, p. 3490. no. 183.
282
DISTICHOTYPHIS Keen & Campbell, 1964: 56 Type sp. (O. D.): Distichotvphis vemae Keen & Campbell. 1964, The Veliger 7(1): 56-57, pi. 11. figs. 45-47.
DRUPA Roding, 1798: 55 Type sp. (S. D. Rovereto, 1899): Drupa morun, Roding, 1798, Museum Boltenianum p. 55, no. 694.
DRUPELLA Thiele. 1925: 137
Type sp. (S. D. Wenz, 1941): Drupa (Drupella) ochrostoma (Blainville, 1832), Nouv. Ann. Mus. Hist. Nat. Paris ser. 3, 1: 205.
DRUPINA Dall, 1923: 303
Type sp. (O. D.): Ricinula digitata Lamarck, 1816 (= Drupa grossularia Roding, 1798), Tableau Encycl. Meth. pi. 395, fig. 7a, 7b, Liste, p. 2.
tECPHORA Conrad. 1843: 310
Type sp. (O. D.): Fusus quadricostatus Say, 1824, J. Acad. Nat. Sci. Philadelphia 4: 127.
EMOZAMIA Iredale, 1929a: 185
Type sp. (O. D.): Murex licinus Hedley and Pet- terd, 1906, Rec. Australian Mus. 6: 219, pi. 37, fig. 6.
ENATIMENE Iredale, 1929a: 185
Type sp. (O. D.): Trophon simplex Hedley, 1903, Mem. Australian Mus. 4(1): 380.
ENIXOTROPHON Iredale, 1929a: 185
Type sp. (O. D.): Trophon carduelis Watson, 1882, MoUusca of H. M. S. Challenger Expedi- tion, pt. 14. p. 388.
tENTACANTHUS Ihering, 1907: 183
Type sp. (M.): Trophon monoceros Ihering, 1907, Anal. Mus. Nac. Buenos Aires 14: 183.
tEOTYPHIS Tembrock, 1963: 322
Type sp. (O. D.): Typhis sejunctus Semper, 1861, Arch. Verens. Freunde Naturg. Mecklen. 15: 161.
ERGALATAX Iredale, 1931: 231
Type sp. (O. D.): Ergalatax recurrens Iredale, 1931 (= Buccinum contractum Reeve, 1846), Rec. Australian Mus. 18: 231.
EUPHYLLON Jousseaume, 1880: 335
Type sp. (O. D.): Murex monodon Sowerby, 1825 (= Murex comucervi Roding, 1798), Cat. Shells Tankerville, App., p. 19, sp. 1703.
EVOKESIA Radwin & D'Attilio, 1972: 335
Type sp. (O. D.): Sistrum rufonotatum Carpenter, 1864, Ann. Mag. Nat. Hist.", ser. 3, 14:. 48.
EUPLEURA H. & A. Adams, 1853: 107
Type sp. (S. D., F. C. Baker, 1895): Ranella caudata Say, 1822, J. Acad. Nat. Sci. Philadelphia 2: 236.
FAVARTIA Jousseaume, 1880: 335
Type sp. (O. D.): Murex breviculus Sowerby, 1834, Conch. Illust., pi. 63, fig. 37.
tFLEXOPTERON Shuto, 1969: 112
Type sp. (O. D.): Flexopteron philippinensis Shuto, 1969, Mem. Fac. Sci. Kyushu Univ. (ser. Geol.) 19: 112.
FORRERIA Jousseaume, 1880: 335
Type sp. (O. D.): Murex belcheri Hinds 1844, Proc. Zool. Soc. London 11: 128.
FRONDOSARIA Schluter, 1838: 20 Type sp. (S. D., E. H. Yokes, 1964): Frondosaria inflata (Lamarck, 1822) (= Murex ramosus Linne, 1758), Hist. Nat. Anim. s. Vert. 7: 160.
FUEGOTROPHON Powell, 1951: 157
Type sp. (O. D.): Fusus crispus Gould, 1849 ( = Murex pallidus Broderip, 1833), Proc. Boston
Soc. Nat. Hist. 3: 141. tFULGUROFUSUS Grabau, 1904: 86
Type sp. (O. D.): Fusus quercollis Harris, 1896, Bull. Amer. Paleo. 1: 200, pi. 18, fig. 9. FUSOMUREX Coen, 1922: 69 Type sp. (O. D.): Purpura alucoides Blainville, 1829, Faune Francaise, p. 128, pi. 5b, fig. 1.
tGALEROPSIS Hupe, 1860: 127
Type sp. (O. D.): Galeropsis lavenavana Hupe, 1860, Rev. Mag. Zool. 12: 127.
GALFRIDUS Iredale, 1924: 271
Type sp. (O. D.): Triton (Cumia) speciosum Angas, 1871, Proc. Zool. Soc. London, 89: 13, pi. 1, fig. 1.
GEMIXYSTUS Iredale, 1929a: 185
Type sp. (O. D.): Trophon laminatus Petterd, 1884, J. Conch., 4: 136, pi. 22, fig. 3.
GENKAIMUREX Kuroda, 1953: 120
Type sp. (O. D.): Coralliophila (Genkaimurex) varicosa Kuroda, 1953 (= Murex fimbriatulum A. Adams, 1863). Venus 17: 120.
GRACILIMUREX Thiele, 1929: 289
Type sp. (O. D.): Gracilimurex bicolor Thiele, 1929, Handbuch Syst. Weichtier., p. 289.
GRACILIPURPURA Jousseaume, 1880: 335
Type sp. (O. D.): Fusus strigosus Lamarck, 1822, Hist. Nat. Anim. s. Vert. 7: 130.
HADRIANIA Bucquoy & Dautzenberg, 1882: 16, 33 Type sp. (O. D.): Murex craticulatus Brocchi, 1814 (not Linne, 1758) (= Hadriania craticuloides E. H. Vokes, 1964), Conch. Foss. Subapp., 2: 406, pi. 7, fig. 14.
HANETIA Jousseaume, 1880: 335 Type sp. (O. D.): Murex haneti Petit, 1856, J. Conchyl. 5: 90.
tHARMATIA Noszky, 1940: 28
Type sp. (O. D.): Murex (Harmatia) stephani Noszky, 1940, Ann. Hist. Nat. Mus. Hung. Min. Geol. 33: 1-80.
HAUSTELLARIA Swainson, 1833: pi. 100
Type sp. (O. D.): Haustellaria haustellum Linne, 1758, Syst. Nat., Ed. 10, p. 746, no. 493.
HAUSTELLOTYPHIS Jousseaume, 1880: 335 Type sp. (O. D.): Typhis cumingi Broderip, 1833, Proc. Comm. Sci. Corr. Zool. Soc. London 2: 177.
HAUSTELLUM "Klein" Bruguiere, 1792: 533 Type sp. (S. M., Schumacher, 1817), Murex haustellum Linne, 1758, p. 746, no. 213.
HAUSTRUM Perry, 1811: pi. 44 Type sp. (S. D. Iredale, 1915): Buccinum haustrum Martyn, 1788 (non-binominal) ( = Buccinum haustorium Gmelin, 1791), Univ. Conch., vol. 2, fig. 9c.
HERTLEINELLA Berry, 1958: 95
Type sp. (O. D.): Hertleinella leucostephes Berry, 1958, 1(16): 95.
tHETEROPURPURA Jousseaume, 1880: 335 Type sp. (O. D.): Murex polymorphus Brocchi, 1814, Conch. Foss. Subapp. 2: 415, pi. 8, figs. 4a, 4b.
tHEXACHORDA Cossmann, 1903: 47
Type sp. (O. D.): Murex tenellus Mayer-Eymar, 1869, J. Conchyl. 17: 82, pi. 3 fig. 5.
HEXAPLEX Perry, 1811: pi. 8
Type sp. (S. D. Jousseaume, 1880): Murex cichoreum Gmelin, 1791, Syst. Nat., Ed. 13, 1: 3530.
tHIPPOCAMPOIDES Wade, 1916: 466 Type sp. (O. D.): Hippocampoides serratus
283
Wade, 1916. Proc. Acad. Nat. Sci. Philadelphia 68: 466. pi. 24, figs. 11-13.
HIRTOMUREX Coen. 1922: 69
Type sp. (O. D.): Fusus lamellosa Philippi, 1836, Enum. Moll. Sicil., p. 204.
tHIRTOTYPHIS Jousseaume, 1880: 336
Type sp. (O. D.): Murex horridus Brocchi, 1814, Conch. Foss. Subapp., 2: 405, pi. 7, fig. 17.
tHISPIDOFUSUS Darragh, 1969: 67
Type sp. (O. D.): Fusus senticosus Tate, 1888, Trans. Roy. Soc. S. Austr., 10: 135, pi. 7, fig. 3.
HISTRICOSCEPTRUM Darragh, 1969: 87
Type sp. (O. D.): Columbarium atlantis Clench & Aguayo, 1938, Mem. Soc. Cuba Hist. Nat. vol. 12(5): 382, pi. 28, fig. 1.
HOMALOCANTHA Morch, 1852: 95
Type sp. (M.): Murex scorpio Linne, 1758, Syst. Nat. Ed. 10, p. 747, no. 449.
tINDOTYPHIS Keen, 1944: 59
Type sp. (O. D.): Laevityphis (Indotyphis) hantamensis (Oostingh, 1933), De Mijningenieur, Jaarg. 14, p. 193.
INERMICOSTA Jousseaume, 1880: 335 Type sp. (O. D.): Murex fasciat us Sowerby, 1841, Proc. Zool. Soc. London 8: 144.
lOPAS H. & A. Adams, 1853: 128
Type sp. (S. D. Dall, 1909): Purpura sertum Lamarck, 1816 (= Buccinum sertum Bruguiere, 1789), Tableau Encycl. Meth.. pi. 397, fig. 2, Liste p. 2.
JANIA Cossmann, 1892: 68
Type sp. (O. D.): Murex blainvillei Payraudeau, 1826, Cat. Moll. Corse, p. 149.
JATON Pusch, 1837: 135
Type sp. (O. D.): Murex decussatus Gmelin, 1791, Syst. Nat. Ed. 13, p. 3527, no. 7.
JATOVA Jousseaume, 1880: 335
Type sp. (O. D.): Purpura jatou Adanson, 1757 (non-binominal) (= Murex decussatus Gmelin, 1791), Hist. Nat. du Senegal. Coquillages, p. 129, pi. 9, fig. 21.
KALYDON Hutton, 1884: 220 (not to be confused
with Calydon J. Thomson, 1864) (Kalydon
suppressed — ICZN Opin. 911, 1970, Bull.
Zool. Nomencl. 27: 20).
Type sp. (O. D.): Fusus plebeius Hutton, 1873,
Cat. Mar. Moll. New Zealand p. 9.
LAEVITYPHIS Cossmann, 1903: 59
Type sp. (O. D.): Typhis coronarius Deshayes, 1865 (= Typhis muticus J. Sowerby, 1834), Descr. Anim. s. Vert, decouv. Bassin de Paris, p. 335, pi. 88, figs. 11-13.
LAMELLATIAXIS Habe & Kosuge, 1970: 182 Type sp. (O. D.): Latiaxis (Lamellatiaxis) marumai Habe & Kosuge, 1970, Venus 24(4): 182.
LATAXIENA Jousseaume, 1883: 187
Type sp. (T.): Lataxiena lataxiena Jousseaume, 1883 (== Trophon fimbriatus Hinds, 1844), Bull. Soc. Zool. Franc. 8: 187.
LATIAXIS Swainson, 1840: 82, 306
Type sp. (M.): Pyrula mawae "Gray" Griffith & Pidgeon, 1834, (in, Cuvier, Regne Animal) Mollusca & Radiata, p. 599, pi. 25, figs. 3, 4.
LATIMUREX Coen, 1922: 70
Type sp. (O. D.): Murex meyendorffi Calcara, 1845, Cenne Moll. Sicil., p. 38.
LENITROPHON Finlay, 1927: 424 Type sp. (O. D.): Trophon convexus Suter, 1909, Rec. Canterbury Mus. 1(2): 126, pi. 12, fig. 4.
LEPADOMUREX Coen, 1922: 70
Type sp. (O. D.): Purpura brevis Blainville, 1832, Nouv. Ann. Mus. Hist. Nat. Paris, vol. 1(2): 233.
LEPSIA Hutton, 1884: 223
Type sp. (O. D.): Purpura haustrum Martyn, 1788 {— Buccinum haustorium Gmelin, 1791), Univ. Conch., vol. 2, fig. 9c.
LEPSIELLA Iredale, 1912: 223
Type sp. (O. D.): Purpura scobina Quoy & Gaimard, 1833, Voyage of the "Astrolabe," Zool. II, p. 567.
LEPSITHAIS Finaly, 1928: 258
Type sp. (O. D.): Polvtropa squamata Hutton, 1878. J. Conchyl. 26: 19.
LEPTOCONCHUS Ruppell, 1834: 105
Type sp. (S. D. Gray, 1847): Leptoconchus peroni Lamarck, 1818, Hist. Nat. Anim. s. Vert. 5: 374.
LINIAXIS Laseron, 1955: 72 Type sp. (O. D.): Liniaxis elongata Laseron, 1955, Proc. Roy. Zool. Soc. New South Wales 1953-54: 72.
LITOZAMIA Iredale, 1929a: 185
Type sp. (O. D.): Peristemia rudolphi Henn & Brazier, 1894, Proc. Linn. Soc. New South Wales 19: 166, pi. 14, fig. 1.
tLOWENSTAMIA Sohl, 1964a: 182
Type sp. (O. D.): Lowenstamia funiculus Sohl, 1964, U.S. Geol. Surv. Prof. Paper 331b: 182, pi. 21, figs. 23, 26.
tLYROPURPURA Jousseaume, 1880: 335 Type sp. (O. D.): Murex crassicostata (Deshayes, 1835, Descrip. Coq. Foss. Environ, de Paris 2: 601, pi. 82, figs. 13, 14.
tLYROTHYPHIS Jousseaume, 1880: 336 Type sp. (O. D.): Typhis cuniculosus Duchatel, (in Bronn), 1848 (= Murex cuniculosus Nyst, 1836). Mess. Sci. Arts Belg. 4: 176.
MACULOTRITON Dall, 1904: 136
Type sp. (O. D.): Triton bracteata Hinds, 1844, Proc. Zool. Soc. London, 12: 132.
MAGILOPSIS Sowerby, 1919: 77
Type sp. (O. D.): Leptoconchus lamarcki Des- hayes, 1863, Cat. Moll. Conchyl. L'ile de la Reunion (Bourbon), p. 127, pi. 12, figs. 1-3.
MAGILUS Montfort, 1810: 42
Type sp. (O. D.): Magilus antiquus Montfort, 1810, 2: 42.
MANCINELLA Link, 1807: 115
Type sp. (T.): Murex mancinella Linne, 1758 ( = Mancinella aculeata Link, 1807), Syst. Nat. Ed. 10, p. 751, no. 469.
MARCHIA Jousseaume, 1880: 335
Type sp. (O. D.): Murex clavus Kiener, 1843 ( = Murex elongata Lightfoot, 1786), Spec. Gen. Icon. Coq. Viv. 7: 111, pi. 37, fig. 2.
MAXWELLIA Baily, 1950: 9
Type sp. (O. D.): Murex gemma Sowerby, 1879, Thes. Conch., vol. 4, Murex, p. 32, fig. 214.
MENATHAIS Iredale, 1937: 256 Type sp. (O. D.): Purpura pica Blainville, 1832, Nouv. Ann. Mus. Hist. Nat. Paris, ser. 3, 1: 213.
tMICRORHYTIS Emerson, 1959: 6
Type sp. (O. D.): Pterorytis (Microrhytis) pecki Emerson, 1959, Amer. Mus. Novitates 1974.
MICROTOMA Swainson, 1840: 301
Type sp. (S. D. Gray, 1847 [as Microstoma]): Microtoma persica (Lamarck, 1799), Mem. Soc. Hist. Nat. Paris, p. 71.
MINNIMUREX Woolacott, 1957: 115
284
Type sp. (O. D.): Minnimurex phantom Woola- cott, 1957, Proc. Roy. Soc. New South Wales, 1955-56. p. 115.
MINORTROPHON Finlay, 1927: 425
Type sp. (O. D.): Daphnella crassilirata Suter, 1908, Trans. Proc. New Zealand Inst. 57: 425.
tMIOCENEBRA E. H. Yokes, 1963: 162
Type sp. (O. D.): Tritonalia (Miocenebra) silverdalense E. H. Yokes, 1963, Tulane Stud. Geol. 1(4): 162, pi. 2, figs. 6a, 6b, 7a, 7b.
MIPUS De Gregorio, 1885: 28
Type sp. (O. D.): Trophon gyratum Hinds, 1844, Yoy. H. M. S. Sulphur, Zoology, 2: 14, pi. 1, figs. 14-15.
MONOCEROS Lamarck, 1822: 250 (not Bloch & Schneider, 1801) Type sp. (S. D., herein): Monoceros imbricatum Lamarck, 1816 (= Buccinum monodon Pallas, 1774), Tabl. Encycl. Meth., pi. 396, figs, la, lb, Liste. p. 2.
MONSTROTYPHIS Habe, 1961: 19 (appendix) Type sp. (O. D.): Typhis (Typhinellus) tosaensis Azuma, 1960, Cat. Shell-bearing Mollusca Okinoshima, Kashiwajima . . . (Tosa Province), Shikoku, Japan., p. 99, pi. 2, fig. 8.
tMOREA Conrad, 1860: 290
Type sp. (M.): Morea cancellaria Conrad, 1860, J. Acad. Nat. Sci., Philadelphia 4: 290.
MORULA Schumacher, 1817: 68, 227
Type sp. (M.): Morula papillosa Schumacher, 1817 (= Drupa uva Roding, 1798), Ess. Yers. Test., pp. 68, 227.
MORULINA Dall, 1923: 303 (not Borner, 1906) Type sp. (O. D.): Ricinula mutica Lamarck, 1816, Tabl. Encycl.
Tabl. Encycl. Meth., pi. 395, figs. 2a, 2b, Liste, p. 1.
MORUNELLA Emerson & Hertlein, 1964: 361 Type sp. (O. D.): Buccinum lugubre C. B. Adams, 1852, Cat. Shells coll. Panama . . ., p. 69.
MUREX Linne, 1758: 746
Type sp. (S. D., Montfort, 1810): Murex pecten Montfort, 1810, (not Lightfoot, 1786), (= Murex tribulus Linne, 1758), Conch. Syst. 2: 619.
MUREXIELLA Clench & Perez Farfante, 1945: 49 Type sp. (O. D.): Murex hidalgoi Crosse, 1869, J. Conchyl. 17: 408.
MUREXSUL Iredale, 1915: 471
Type sp. (O. D.): Murex octogonus Quoy & Gaimard, 1832, Yoyage . . . I'Astrolabe . . . Paris, Zool., Mollusca, 2: 531, pi. 36, figs. 8, 9.
MURICANTHUS Swainson, 1840: 296
New name for Centronotus Swainson, 1833, not Schneider, 1801.
MURICIDEA Swainson, 1840: 64
Type sp. (O. D.): Murex magellanicus Lamarck, 1816 (— Buccinum geversianum Pallas, 1774), Tabl. Encycl. Meth., pi. 419, figs. 4a, 4b, Liste, p. 5.
MURICODRUPA Iredale, 1918: 38
Type sp. (O. D.): Purpura fenestrata Blainville, 1832 (= Murex fvniculus Wood, 1828), Nouv. Ann. Mus. Hist. Nat. Paris 1: 221.
MURICOPSIS Bucquoy & Dautzenberg, 1882: 16, 19 Type sp. (O. D.): Murex blainvillei Payraudeau, 1826, Cat. Descr. Meth. Annel. Moll. lie de Corse, p. 149.
MURITHAIS Grant & Gale, 1931: 729
Type sp. (O. D.): Murex trunculus Linne, 1758, Syst. Nat. Ed. 10, p. 747, no. 447. tMUROTRITON de Gregorio, 1890: 97
Type sp. (O. D.): Triton grassator de Gregorio, 1890, Ann. Geol. Paleo. 7: 97. NAQUETIA Jousseaume, 1880: 335
Type sp. (O. D.): Murex triqueter Born, 1778, Index Mus. Caes. Yindobon., p. 288. NAMAMUREX Carrington & Kensley, 1969: 197
Type sp. (O. D.): Namamurex odontostoma
Carrington & Kensley, 1969, Ann. S. Afr. Mus.
52: 197. NASSA Roding, 1798: 132
Type sp. (S. D., Dall 1909): Nassa picta Roding, 1798 (= Buccinum sertum Bruguiere, 1789), Museum Boltenianum, p. 132. NEMOFUSUS Cossmann, 1903: 195
Type sp. (O. D.): Murex fusulus Brocchi, 1814, Conch. Foss. Subapp. 2: 409, pi. 8, fig. 9. NEORAPANA Cooke, 1918: 7, 11
Type sp. (O. D.): Purpura muricata Broderip,
1832, Proc. Comm. Sci. Zool. Soc. London, 2:
125, 126. NEOTHIAS Iredale, 1912: 223
Type sp. (O. D.): Purpura smithi Brazier, 1889,
Mem. Australian Mus. 2: pi. 4, figs. 1-4, 7-12,
21. 22. tNEOTYPHlS Yella, 1961: 385
Type sp. (O. D.): Typhis tepunga Fleming, 1943,
Trans. Roy. Soc. New Zealand 73(3): 205, pi. 30,
fig. 21. tNEURARHYTIS Olsson & Harbison, 1953: 252
Type sp. (O. D.): Purpura (Pterorhytis) fluviana
(Dall, 1903), Trans. Wagner Free Inst. Sci. 3(6):
1633, pi. 60, figs. 20, 21. NIPPONOTROPHON Kuroda & Habe, 1971: 233 (Japanese), 152 (English)
Type sp. (O. D.): Boreotrophon echinus Dall,
1920. Proc. U.S. Natl. Mus. 54: 232. NODULOTROPHON Habe & Ito, 1965: 32-33
Typesp. (O. D.): Trophon dalli. Kobelt, 1878 (in
Kiister) Martini & Chemnitz Conchylien-Cabinet,
pt. 275, p. 289, pi. 74, figs. 1, 2. NOTHOTYPHIS Fleming, 1962: 109, 119
Type sp. (O.D.): Pterynotus (Nothotyphis)
norfolkensis Fleming, 1962, Trans. Roy. Soc. New
Zealand 2(14): 109, 119. NUCELLA Roding, 1798: 131
Type sp. (S. D. Winckworth, 1945): Nucella
theobromus Roding, 1798 (= Buccinum lapillus
Linne. 1758), Mus. Bolten. p. 131. OCINEBRELLUS Jousseaume, 1880: 335
Type sp. (O. D.): Murex eurypteron Reeve, 1845,
Conch. Icon., vol. 3, Murex, sp. 176, pi. 34, fig.
176a, 176b. OCENEBRA Gray, 1847a: 269
Type sp. (M.): Murex erinaceus Linne, 1758,
Syst. Nat. Ed. 10, p. 748, no. 451. OCINEBRINA Jousseaum, 1880: 335
Type sp. (O. D.): Fusus corallinus Scacchi, 1836
(= Murex aciculatus Lamarck, 1822), Cat.
Conch. Neap., p. 11. OLLAPHON Iredale, 1929a: 186
Type sp. (O. D.): Trophon molorthus Hedley &
May, 1908, Rec. Australian Mus. 7: 122. OPPOMORUS Iredale, 1937: 258
Type sp. (O. D.): Morula nodulifera Menke,
1829, Conch. Samml. Malsburg, p. 33. ORANIA Pallary, 1900: 285
285
Type sp. (O. D.): Pseudomurex spadae Libassi, 1859, Atti Acad. Palermo, 3: 43, fig. 29.
PAGODULA Monterosato, 1884: 116
Type sp. (O. D.): Murex vaginata Cristofori & Jan, 1832, Cat. . . . rerum Nat. Mus. Extant. Josephi de Cristofori, Sect. 11(1), Conch. Fossili, p. 11.
tPANAMUREX Woodring, 1959: 217
Type sp. (O. D.): Murex gatunensis Brown & Pilsbry, 1911, Proc. Acad. Nat. Sci. Philadelphia 63: 354, pi. 26, fig. 2.
PARATROPHON Finlay, 1927: 424
Type sp. (O. D.): Polvtropa cheesemani Hutton, 1882, New Zealand J. Sci. 1: 69.
PASCULA Dall. 1908: 311, 312
Type sp. (O. D.): Trophon (Pascula) citricus Dall, 1908. Bull. Mus. Comp. Zool. 43(6): 312.
PATELLIPURPURA Dall, 1909: 50 Type sp. (O. D.): Buccinum patulum Linne, 1758, Syst. Nat., Ed. 10, p. 739, no. 402.
PAZIELLA Jousseaume, 1880: 335 Type sp. (O. D.): Murex pazi Crosse, 1869, J. Conchyl., 17: 183.
PAZINOTUS E. H. Yokes, 1970b: 27 Type sp. (O. D.): Eupleura stimpsoni Dall, 1889, Bull. Mus. Comp. Zool. 18: 204.
PENTADACTYLUS "Klein" Bruguiere, 1792: 520 (not Schultze, 1760) Type sp. (S. D., P. C. Baker, 1895): Pentadactylus ricinus Lamarck (= Murex ricinus Linne, 1758, Syst. Nat., Ed. 10, p. 750, no. 464.)
tPERITROPHON Marwick, 1931: 119
Type sp. (O.D.): Peritrophon decoratus Marwick, 1931, Paleont. Bull. New Zealand no. 13: 119.
PEROTYPHIS Jousseaume, 1880: 336 (error for Pterotyphis — q.v.) Type sp. (O.D.): Typhis pinnatus Broderip, 1833, Proc. Comm. Sci. Corr. Zool. Soc. London 2: 178.
PHYLLOCOMA Tapparone-Canefri. 1881: 44 Type sp. (O. D.): Triton convolutus Broderip, 1833, Proc. Zool. Soc. London 1: 7.
PHYLLONOTUS Swainson, 1833: pi. 100 Type sp. (S. D. Swainson, 1833 — pi. 109): Murex imperialis (var.a) Swainson, 1833 ( = Murex imperialis. Swainson, 1831) (not Fischer de Waldheim, 1807), (= Murex margaritensis Abbott, 1958), Zool. Illust., ser. 2, 3: pi. 100.
PHRYGIOMUREX Dall, 1904: 137 Type sp. (O. D.): Triton sculptilis Reeve, 1844, Proc. Zool. Soc. London 12: 118-119.
tPILSBRYTYPHIS Woodring, 1959: 220
Type sp. (O. D.): Typhis gabbi Brown & Pilsbry, 1911, Proc. Acad. Nat. Sci. Philadelphia 63: 354, pi. 26, fig. 6.
PINAXIA H. & A. Adams, 1853: 132 Type sp. (M.): Pinaxia coronata H. & A. Adams, 1853 (nomen nudem) (= Pinaxia coronata A. Adams, 1853, Proc. Zool. Soc. London 19: 185).
PINON de Gregorio, 1885: 28
Type sp. (O. D.): Trophon (Pinon) vaginatus Cristofori & Jan, 1832, Cat. rerum Nat. Mus. Sect. 11(1), Conch. Foss., p. 11.
tPIRGOS de Gregorio, 1885: 28
Type sp. (S. D., Cossmann, 1904): Fusus alveolatus J. Sowerby, 1823, Min. Conch. 5: 9.
PIRTUS de Gregorio, 1884: 257
Type sp. (O. D.): Murex (Pirtus) fiatus de Gregorio, 1884, Bull. Soc. Malac. Ital. 10: 257.
PLANITHAIS "Bayle" Fischer, 1884: 645
Type sp. (O. D.): Purpura planospira Lamarck, 1822, Hist. Nat. Anim. s. Vert. 7: 240.
PLICOPURPURA Cossmann, 1903: 69
New name for Purpurella Daii, 1871, not Robineau-Desvoidy, 1853.
POIRIERIA Jousseaume, 1880: 335
Type sp. (O. D.): Murex zelandicus Quoy & Gaimard, 1833, Voy. Astrolabe, Zool. 2: 529, pi. 36. figs. 5-7.
POLYPLEX Perry, 1811: pi. 9 Type sp. (S. D., ICZN Opinion 911, 1969 — see Bull. Zool. Nomencl., 27: 20): Polyplex bulbosa Perry, 1811, Conchology, pi. 9.
POLYTROPA Swainson, 1840: 305
Type sp. (S. D., Gray, 1847): Buccinum lapillus Linne, 1758. Syst. Nat., Ed. 10, p. 739, no. 403.
POROPTERON Jousseaume, 1880: 335 Type sp. (O. D.): Murex tubifer Bruguiere, 1972, (an apparent error as Jousseaume also designated this species as type of Typhis Montfort) Type sp. (S. D. Jousseaume, 1881): Murex uncinarius Lamarck, 1822, Hist. Nat. Anim. s. Vert. 7: 166.
POWERIA Monterosato, 1884: 113 (not Bonaparte, 1841) Type sp. (M.): Poweria scalarina Bivona, 1832 ( — Murex scalaroides Blainville, 1826), Effem. Lett. Sicii., p. 22.
PROTOTYPHIS Ponder, 1972: 221
Type sp. (O. D.): Typhis angasi Crosse, 1863, J Conchyl. 11: 86, pi. 1, fig. 2.
PROVEXILLUM Hedley. 1918: 79
New name for Vexilla Swainson, 1840, not Vexil- lum Roding, 1798.
tPSEUDOMOREA Cossmann, 1925: 265 Type sp. (M.): Morea marylandica Gardner, 1916, Maryland Geol. Survey, Upper Cretaceous, Syst. Paleo. Mollusca, p. 371.
PSEUDOMUREX Monterosato, 1872: 15, 33
Type sp. (O. D.): Murex bracteata Brocchi, 1814, Moll. Foss. Subapp., p. 409, pi. 9, fig. 3.
tPSEUDORAPA Holzapfel, 1888: 111
Type sp. (O. D.): Murex pleurotomoides Muller, 1851, vol. 1, Mon. 2, p. 24, pi. 3, fig. 31.
PSEUDOSALPINX Olsson & Harbison, et al., 1953: 254 Type sp. (O. D.): Urosalpinx floridana (Conrad, 1837) (= Murex ostrearum Conrad, 1846), J. Acad. Nat. Sci. Philadelphia 7: 265.
PTEROCHELUS Jousseaume, 1880: 335 Type sp. (O. D.): Murex acanthopterus Lamarck, 1816, Tabl. Encycl. Meth. pi. 417, figs. 2a, 2b, Liste, p. 5.
PTEROPURPURA Jousseaume, 1880: 335
Type sp. (O. D.): Murex macropterus Deshayes, 1839, Rev. Zool. Soc. Cuv. 2: 360.
PTERORYTIS Conrad, 1862: 17
Type sp. (O. D.): Murex umbrifer Conrad, 1832, Foss. Shells Tert. form. N. Amer. 1: 17, pi. 3,
fig. 1. PTEROTYPHIS Jousseaume, 1881: 338 (Emenda- tion for Perotvphis Jousseaume, 1880) PTERYMUREX Rovereto, 1899: 105
New name for Pteronotus Swainson, 1833, not
Rafinesque, 1815. tPTERYNOPSIS E. H. Vokes, 1972: 1
Type sp. (O. D.): Pterynopsis prosopeion E. H.
Vokes, 1972 (= Murex nysti von Koenen, 1867,
not Roualt, 1850), Bull. Inst. R. Sci. Nat. Belg.
286
48(9): 2.
PTERYNOTUS Swainson. 1833: pi. 100
Type sp. (S. D. Swainson. 1833, pi. 122): Murex pinnatus Swainson, 1822 (= Purpura alatus Roding. 1798), App. Cat. Bligh, p. 17.
PURPURA Bruguiere. 1789: xv
Type sp. (S. D., Montfort, 1810): Buccinum pepsicum Linne, 1758, Syst. Nat.. Ed. 10, p. 738, no. 401.
PURPURELLA Dall, 1871: 110 (not Bellardi, 1882, nor Robineau-Desvoidy, 1853) Type sp. (O. D.): Purpura columellaris Lamarck, 1816, Tabl. Encycl. Meth.. pi. 398, figs. 3a, 3b, Liste. p. 2.
tPURPURELLA Bellardi. 1882: 193 (not Dall, 1871. nor Robineau-Desvoidy, 1853) Type sp. (M.): Purpurella canaliculata Bellardi, 1882, Moll. Terr. Terz. Piem. Ligur. pt. 3, p. 193, pi. 11, fig. 35.
PURPURELLUS Jousseaume, 1880: 335
Type sp. (O. D.): Murex gambiensis Reeve, 1845, Conch. Icon. vol. 3. Murex. pi. 16, sp. 65.
tPURPURINA Cox, 1961: 10
Type sp. (O. D.): Purpurina yanreyensis Cox, 1961, Bull. Australian Bur. Min. Res. Geol. Geophys., pp. 10, 33, pi. 7, figs. 6a, 6b.
QUOYULA Iredale. 1912: 221
Type sp. (O. D): Purpura monodonta Quoy & Gaimard, 1833, Voy. Astrolabe. Zool. 2, p. 561, pi. 37. figs. 9. 11.
RAPA "Klein" Bruguiere. 1792: 533 Type sp. (S. D.. Herrmannsen. 1848): Bulla rapa (Linne, 1767) (= Murex rapa Linne. 1758. not Gmelin. 1791). Syst. Nat. Ed. 12. p. 1184. no. 384.
RAPANA Schumacher. 1817: 214 Type sp. (M.): Rapana foliacea Schumacher. 1817 (= Buccinum bezoar Linne, 1758), Ess. Vers. Test., p. 214.
RAPANUS "Schum." Sowerby, 1839: 92
Type sp. (M.): Pyrula papyracea [Lamarck, 1816] (= Rapa rapa Bruguiere, 1792), Tabl. Encycl. Meth. pi. 436, fig. 1.
RAPELLA Swainson, 1840: 82, 307 Type sp. (M.): Rapella papracia (sic) (Lamarck, 1816), Tabl. Encycl. Meth. pi. 436, fig. 1, Liste, p. 8.
RHINOCANTHA H. & A. Adams, 1853: 72 Type sp. (S. D., E. H. Yokes, 1964): Murex brandaris Linne, 1758, Syst. Nat., Ed. 10, p. 747, no. 446.
RHIZOCHILUS Steenstrup. 1850: 75
Type sp. (M.): Rhizochilus antipathum Steen- strup. 1850, Overs. K. Danske Vidensk. Selsk. Forh. 1850: 75.
RHIZOPHORIMUREX Oyama. 1950: 10
Type sp. (O. D.): Murex capuchinus (sic) Lamarck, 1822, Hist. Nat. Anim. s. Vert. 7: 164.
RHOMBOTHAIS Woolacott, 1954: 38
Type sp. (O. D.): Rhombothais arbutum Wool- acott, 1954, Proc. Roy. Soc. Zool. Soc. New South Wales, 1952-53: 38, pi. 3. figs. 1, 2.
RICINELLA Schumacher. 1817: 72
Type sp. (S. D., Iredale, 1937): Ricinella pur- purata Schumacher, 1817, Ess. Syst. Vers. Test., p. 72.
RICINULA Lamarck, 1816: 1
Type sp. (S. D., Children. 1823): Ricinula huridu (sic) Lamarck. 1816, Tabl. Encycl. Meth.. pi. 395,
figs, la, lb.
RISOMUREX Olsson & McGinty, 1958: 40
Typesp. (O. D.): Engina schrammi Crosse, 1863, J. Conchyl. 11: 86, pi. 1, fig. 2.
ROPERIA Dall, 1898: 5 Type sp. (O. D.): Fusus roperi Dall, 1898, The Nautilus 12(1): 5.
RUDOLPHA Schumacher, 1817: 63, 210
Type sp. (O. D.): Buccinum mo«oceros Chemnitz, 1788 (non-bionominal) (= Buccinum monodon Pallas, 1774), Neues Systematisches Conchylien- Cabinet 10: 197. pi. 154. figs. 1469, 1470.
tRUGOTYPHlS Vella, 1961: 376
Typesp. (O. D.): Typhis francescae Finlay. 1924. Trans. Proc. New Zealand Inst. 55: 465, pi. 49, figs. 6a, 6b.
tSARGANA Stephenson, 1923: 377 Type sp. (O. D.): Rapana stantoni Stephenson, 1923, North Carolina Geol. Surv.. 5: 377.
tSCALASPIRA Conrad. 1862: 560
Type sp. (M.): Fusus strumosa Conrad, 1862, Proc. Acad. Nat. Sci. Philadelphia 14: 560.
SEMIRICINULA von Martens, 1903: 95 Type sp. (M.): Purpura muricina Blainville. 1832, Nouv. Ann. Mus. Hist. Nat. Paris 1: 218.
tSEMITYPHIS K. Martin. 1931: 31
Type sp. (M.): Semitvphis incisus K. Martin, 1931, Wetens. Meded.'l8: 31, pi. 5, figs, la, lb.
tSERRATIFUSUS Darragh. 1969: 89
Type sp. (O. D.): Fusus crasspedotus Tate, 1888, Trans. Roy. Soc. South Australia 10: 134. pi. 8. fig. 4.
SHASKYUS Burch & Campbell. 1963: 203 Type sp. (O. D.): Murex festivus Hinds. 1844. Proc. Zool. Soc. London 11: 127.
SIPHONOCHELUS Jousseaume. 1880: 335 Type sp. (O. D.): Typhis avenatus (sic) Hinds, 1843 (= T. arcuatu's Hinds. 1843), Proc. Zool. Soc. London 11: 19.
SIRATUS Jousseaume, 1880: 335 Type sp. (O. D.): Purpura sirat Adanson, 1757 (non-binominal) (= Murex senegalensis Gmelin, 1791), Hist. Nat. Senegal, p. 125.
SISTRUM Montfort, 1810: 595 Type sp. (M.): Sistrum album Montfort, 1810, Conch. Syst. 2: 595.
SPINIDRUPA Habe & Kosuge, 1966: 330
Type sp. (O. D.): Murex euracantha A. Adams, 1851, Proc. Zool. Soc. London 18: 268.
SPINOSTOMA Coen, 1943: 90 Type sp. (S. D. herein): Murex nuttalli Conrad, 1837, J. Acad. Nat. Sci. Philadelphia 7: 264, pi. 20, tig. 22.
STRAMONITA Schumacher, 1817: 226
Type sp. (S. D. Gray, 1847): Buccinum haemas- toma Linne, 1867, Syst. Nat., Ed. 12, p. 1202, no. 566.
STRAMONITROPHON Powell, 1951: 156
Type sp. (O. D.): Buccinum laciniatus Martyn, 1788 (non-binominal) (= Buccinum laciniatum "Martyn" Diilwyn, 1817), Univ. Conch. 2:42.
SUBPTERYNOTUS Olsson & Harbison. 1953: 246 Type sp. (O. D.): Murex textilis Gabb, 1873, Trans. Amer. Philos. Soc. (n.s.) 15(1): 202.
TAKIA Kuroda, 1953: 190
Type sp. (O. D.): Murex inermis Sowerby, 1841 (not Philippi, 1836) (= Dermomurex [Takia] infrons E. H. Vokes, 1974), Venus 17(4): 190.
TALITYPHIS Jousseaume. 1882: 338
287
Type sp. (O. D.): Typhis expansus Sowerby, 1874,
Proc. Zool. Soc. LxJndon 42: 719, pi. 59, fig. 4. TARANTELLAXIS Habe, 1970: 85
Type sp. (M.): Tarantellaxis kuroharai Habe,
1970, Venus 29(3): 85. tTAURASIA Bellardi, 1882: 194
Type sp. (O. D.): Purpura subfusiformis Orbigny,
1952. Prodrome Paleont ... 3: 15. TENGUELLA Arakawa. 1965: 123
Type sp. (O. D.): Morula granulata Duclos, 1924
(sic) (correct date Duclos, 1832). Ann. Sci. Nat.
26(101): 111. TEREFUNDUS Finlay, 1927: 425
Type sp. (O. D.): Trophon crispulatus Suter,
1908, Proc. Malac. Soc. London 8: 178, pi. 7,
fig. 2. TERNARIA Coen, 1943: 89
Type sp. (S. D.. E. H. Yokes, 1964): Murex
eurypteron Reeve. 1845, Conch. Icon., vol. 3,
Murex. pi. 34, sp. 176. THAIS Roding, 1798: 54
Type sp. (S. D. Stewart, 1926): Thais lena Roding,
1798 (= Merita nodosa Linne, 1758, p. 777.) THAISELLA Clench, 1947: 69
Type sp. (O. D.): Purpura trinitatensis Guppy,
1869. Proc. Sci. Assoc. Trinidad 1: 366. THALESSA H. & A. Adams. 1853: 127
Type sp. (S. D., Cossmann. 1903): Purpura hypo-
castaneum "Linne." Cossmann. 1903 (= Murex
hippocastanum "Linne" Auct.) (= Murex hippo-
castanum Gmelin, 1791. p. 3539.) tTIMBELLUS de Gregorio. 1885: 275
Typesp. (O. D.): Murex latifolius Bellardi. 1872,
Moll. Terr. Terz. Piem. Ligur. pt. 1, p. 54, pi. 4,
fig. 5. tTIMOTHIA Palmer, 1938: 3
New name for A Id rich ia Palmer, 1937, not Coquil-
let. 1894. nor Vaughan, 1900. TOLEMA Iredale, 1929a: 186
Type sp. (O. D.): Purpura sertata Hedley, 1903,
Mem. Australian Mus. 4: 382, figs. 95, 96. (ICZN
ruling. Opinion 911, 1970. Bull. Zool. Nomencl.
27: 20 fixed the type as Tolema australis Laseron,
1955). TORVAMUREX Iredale, 1936: 323
Type sp. (O. D.): Triplex denudatus Perry, 1811,
Conchology . . ., pi. 7, fig. 2. TRACHYPOLLIA Woodring, 1928: 268
Type sp. (O. D.): Trachvpollia sclera Woodring,
1928, Carnegie Inst. Wash. Publ. 385: 269, pi. 16, figs. 7, 8.
TRANSTRAFER Iredale, 1929b: 290
Type sp. (O. D.): Transtrafer longmani Iredale,
1929, Mem. Queensland Mus. 9: 290. TRIALATELLA Berry, 1964: 149
Type sp. (O. D.): Trialatella cunninghamae Berry, 1964, Leaflets in Malacology 1(24): 149.
TRIBULUS "Klein" Bruguiere, 1792: 530
Type sp. (S. D., Wenz, 1941): Mancinella {Tri- bulus) planospira Lamarck, 1822, Hist. Nat. Anim. s. Vert. 7: 240.
TRIGONOTYPHIS Jousseaume, 1881: 339
Type sp. (O. D.): Typhis Jimbriatus A. Adams, 1854. Proc. Zool. Soc. London 21: 71.
TRIPLEX Perry. 1810: M7
Type sp. (M.): Triplex foliatus Perry. 1810 ( = Murex palmarosae Lamarck. 1822). The Arcana, or the Museum Nat. Hist., p. M7. (Triplex foliatus Perry has been suppressed by the ICZN, Opinion
911, 1970, Bull. Zool. Nomencl. 27: 20). TRIPTEROTYPHIS Pilsbry & Lowe, 1932: 78
Type sp. (O. D.): Typhis lowei Pilsbry, 1931, The
Nautilus 45(2): 72. TRIREMIS "Bayle" P. Fischer, 1884: 641
Type sp. (M.): Murex gambiensis Reeve, 1845,
Conch. Icon., vol. 3, Murex pi. 16, sp. 65. TRITONALIA "Fleming" Gray, 1847b: 122 (not Fleming, 1828)
Type sp. (O. D.): Murex erinaceus Linne, 1758,
Syst. Nat., Ed. 10. p. 748. no. 451. TROCHIA Swainson, 1840: 302
Type sp. (M.): Trochia sulcata "Lamarck,"
Swainson. 1840 (= Buccinum cingulatum Linne,
1771). Treat. Malac. p. 302. TROMINA Dall. 1918a: 137
Type sp. (O. D.): Fusus unicarinatus Philippi,
1868. Malak. Bl. 15: 223. TROPHON Montfort. 1810: 483
Type sp. (O. D.): Trophon magellanicus Gmelin,
1791 (= Buccinum geversianus Pallas, 1774),
Syst. Nat., Ed. 13, p. 3548, no. 80. TROPHONOPSIS Bucquoy & Dautzenberg, 1882: 40
Type sp. (O. D.): Murex muricatus Montagu,
1803, Test. Brit.. 1: 262. pi. 9, fig. 2. TRUBATSA Dall. 1889: 215
Type sp. (S. D.. Keen, 1944): Typhis (Trubatsa)
longicomis Dall (in, Agassiz), 1888, The Three
Cruises of the "Blake," 2: 70, fig. 294. TRUNCULARIA Monterosato, 1917: 20 (not Wiegmann, 1832)
Type sp. (O. D.): Murex trunculus Linne, 1758,
Syst. Nat., Ed. 10, p. 747, no. 447. TRUNCULARIOPSIS Cossmann, 1921: 79
New name for Truncularia Monterosato, 1917,
not Wiegmann, 1832. TUBICAUDA Jousseaume, 1880: 335
Type sp. (O. D.): Murex brevispina Lamarck,
1822. Hist. Nat. Anim. s. Vert. 7: 159. TYPHINA Jousseaume. 1880: 335
Type sp. (O. D.): Typhis belcheri Broderip. 1833,
Proc. Comm. Sci. Zool. Soc. London 2: 178. TYPHINELLUS Jousseaume. 1880: 335
Type sp. (O. D.): Typhis sowerbiyi (sic) Broderip,
1833 (= Typhis sowerbii Broderip, 1833), Proc.
Comm. Sci. Zool. Soc. London 2: 178. TYPHISALA Jousseaume, 1881: 339
Type sp. (O. D.): Typhis grandis A. Adams, 1855,
Proc. Zool. Soc. London 22: 41. TYPHISOPSIS Jousseaume, 1880: 335
Type sp. (O. D.): Typhis coronatus Broderip,
1833. Proc. Comm. Sci. Zool. Soc. London 2: 178. UNICORNUS Montfort, 1810: 454
Type sp. (O. D.): Unicornus typus Montfort,
1810 (= Buccinum monodon Pallas, 1774),
Conch. Syst. 2: 454, pi. 114. UROSALPINX Stimpson. 1865: 58
Type sp. (O. D.): Fusus cinereus Say, 1822, J.
Acad. Nat. Sci. Philadelphia 2: 236. USILLA H. Adams, 1860: 369
Type sp. (O. D.): Vexilla nigro-fusca Pease, 1860
(= Vexilla fusconigra Pease, 1860), Proc. Zool.
Soc. London 27: 141. tUTTLEYA Marwick, 1934: 19
Type sp. (O. D.): Uttleya arcana Marwick, 1934,
Proc. Malac. Soc. London 21: 19. tVESANULA Finlay. 1926: 245
Type sp. (M.): Trophon chaskanon Finlay, 1926,
288
Trans. New Zealand Inst. 56: 245.
VEXILLA Swainson, 1840: 300
Type sp. (M.): Vexilla picta Swainson, 1840 ( = Murex vexillum Gmelin. 1791), Treat. Malac, p. 300.
VIATOR E. H. Yokes, 1974: 4
Type sp. (O. D.): Viator antonius E. H. Yokes, 1974. J. Malac. Soc. Australia 3(1): 4.
VITULARIA Swainson, 1840: 297
Type sp. (M.): Vitidaria tuberculata Swainson, 1840 (= Murex miliaris Gmelin, 1791), Treat. Malac, p. 297.
VITULINA Swainson, 1840: 64
Type sp. (O. D.): Murex vitulina Lamarck, 1816 (= Murex miliaris Gmelin, 1791), Tabl. Encycl. Meth., pi. 419, figs, la, lb, Liste, p. 5.
tWIDNINGlA Ludbrook, 1941: 95
Type sp. (O. D.): Widningia crassiplicata Lud- brook, 1941, Trans. Roy. Soc. South Australia 65(1): 95.
XANTHOCHORUS P. Fischer, 1884: 639
Type sp. (M.): Trophon xanthostoma Broderip, 1833, Proc. Zool. Soc. London 1: 8.
XENOTROPHON Iredale, 1929a: 184
Type sp. (O. D.): Trophon euschema Iredale, 1929, Rec. Australian Mus. 17: 184, pi. 40, fig. 3.
XYMENE Iredale. 1915: 471
Type sp. (O. D.): Fusus plebius Hutton, 1873, Cat. Mar. Moll. New Zealand, p. 9.
XYMENELLA Finlay, 1927: 424
Type sp. (O. D.): Trophon pusillus Suter, 1907, Trans. New Zealand Inst. 39: 253, pi. 19, fig. 10.
XYMENOPSIS Powell. 1951: 158
Type sp. (O. D.): Fusus liratus "Couthouy" Gould. 1849, Proc. Boston Soc. Nat. Hist. 3: 141.
tYASILA Olsson, 1930: 59
Type sp. (O. D.): Yasila paytensis Olsson, 1930, Bull. Amer. Paleo. 17(62): 59.
ZACATROPHON Hertlein & Strong, 1951: 86 Type sp. (O. D.): Trophon (Zacatrophon) beebei, Hertlein & Strong, 1951, Zoologica 36: 86.
ZEATROPHON Finlay, 1927: 424
Type sp. (O. D.): Fusus ambiguus Philippi, 1844, Abbild. Beschreib. Conch.. Fusus, p. 107. pi. 1. fig. 2.
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Department of Marine Invertebrates, Natural History Museum, San Diego, California 92112.
v5^^^
AU8 191970
BLOOD CIRCULATION IN FOUR SPECIES OF BARNACLES (LEPAS, CONCHODERMA: LEPADIDAE)
BRYAN R. BURNETT
TRANSACTIONS
OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
VOL. 17, NO. 21 20 JUNE 1975
BLOOD CIRCULATION IN FOUR SPECIES OF BARNACLES ilEPAS, CONCHODERMA: LEPADIDAE)
BRYAN R. BURNETT
ABSTRACT. — Circulatory morphologies of the primitive lepadomorphans Lepas anatifera, L. pectinata pacifica. L. fasicularis and Conchoderma virgatum are similar, but major differences appear in vessel caliber and refinement of the basic system. The smaller species (L. fasicularis and L. pectinata pacifica) have larger vessels for their body size than the larger species (Z,. anatifera and C. virgatum). Circulatory organization of the lepadids is simpler than that of Pollicipes polymerus (Scalpellidae) and Balanus tintinnahulum (Balanidae). The lepadid rostral vessel, which is morphologically similar to that of P. polyments, is interpreted as a vestige of the heart. Pump function can be attributed to the rostral sinus (the blood pump), which is apparently a remnant of the pericardial sinus. Transfer of hemolymph pumping from the heart to the rostral sinus probably occurred with the development of the peduncle.
Detailed accounts of cirriped circulation may be found in Cannon (1947) and Burnett (1972). The circulatory systems of Lithotrya valentiana and Pollicipes polymerus (Cannon, 1947) had been considered to represent the general condition for thoracican Cirripedia (e.g. Maynard, 1960). However, Burnett (1972) showed that the circulatory system of the pedunculate barnacle Pollicipes polymerus was unlike that of other Crustacea. In order to obtain a more complete understanding of circulatory relationships in the Cirripedia, I studied the circulatory systems of four species of Lepadidae: Lepas anatifera, L. pectinata pacifica, L. fasicularis and Conchoderma virgatum.
MATERIALS AND METHODS
The three species o^ Lepas were collected from debris that washed ashore at Scripps Institution of Oceanography, La Jolla, California in the summers of 1972 and 1973. The Conchoderma virgatum were collected from a Pacific Ridley sea turtle {Lepidochelys olivacea) captured off La Jolla. Living specimens were injected with yellow (MV-122) or maroon (MV-118) Microfil (Canton Bio-Medical Products, Inc. P.O. Box 2017, Boulder, Colorado 80302), either into the peduncle or through the adductor scutorum into the rostral sinus, following techniques developed in an earlier study (Burnett, 1972). The amount injected ranged from 0.5 to 2.0 ml based on the size of the animal. In each species, the rostral valve at the posterior-most part of the peduncular vessel usually did not hold under the pressure exerted from the Microfil injections into the peduncle; almost always a significant amount of Microfil entered the body via the peduncular vessel. The rostral valve in the lepadids is more delicate than that of P. polymerus: consequently their vessels are more prone to rupture and distort, which makes it difficult to trace circulatory pathways, especially with the peripheral-collecting circulation. In order to determine vessel wall structure, portions of the gut vessels were removed (while they still had solidified Microfil in the vessel lumina) and embedded in Spurr (Polysciences, Inc. Paul Valley Industrial Park, Warrington, Penna. 18976). Sections, 2[j.m thick, were made with a glass knife on a Porter-Blum JB-4 microtome.
Body movements of L. fasicularis were observed through a dissection microscope by shining a light through the thin walled capitulum.
CIRCULATORY MORPHOLOGY
Basically, I shall follow Burnett (1972) in dividing the barnacle circulatory system into three arbitrary divisions: 1) the circulation of the peduncle and mantle, 2) the distributive circulation and 3) the peripheral-collecting circulation.
SAN DIEGO SOC. NAT. HIST.. TRANS. 17(21): 293-304, 20 JUNE 1975
294
AD SCUT AF AD SCUT
S:iir — SCUT VAL
^;5^6»<* •» ^ » y,» ij^^iMati<ya»,f°fe^^£flF mancirc.
>=» o' ^
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OW FR,
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Figure 1 . Mantle circulation in L. anatifera. a. View of the carina with the carinal vessel situated along the
midline of the valve, b. View of the right side of the mantle and a portion of the peduncle. Only the intervalve
circulation is shown, with the arrows representing the direction of hemolymph flow. Basically, this pattern of
circulation is present in L. pectinata pacijlca and C. virgatum. Abbrevations are explained in the Appendix.
Figure 2. Mantle circulation (right side) in L. fasicularis. Arrows show the direction of flow with the heavier
arrows indicating major hemolymph flow.
Figure 3. The origin and associated circulation of the carinal vessel in L. fasicularis.
Figure 4. A portion of the tergal plexus from L. pectinata pacifica.
Figure 5. The double circulation of the mantle in C virgatum.
Figure 6. A portion of the tergal plexus from L. anatifera.
295
Circulation of the peduncle and mantle. — The peduncular vessel extends the full length of the peduncle without giving off any branches, and ends with a gradual enlargement at the basal disc. From the basal disc, the hemolymph percolates towards the mantle, and it appears that the entire peduncle is a single sinus.
Hemolymph from the peduncle enters the mantle circulation by two pathways (Fig. 1). In one route, blood is directed into the mantle circulation from the posterior-most part of the peduncle by a series of short parallel vessels (Fig. lb). From these vessels the blood moves through a plexus toward the ovigerous frena and eventually into the paired scutal vessels. Lepas fasicularis has enlarged vessels entering the mantle in the area between the scutal and carinal regions (Figs. 2, 3).
The other pathway by which the blood enters the mantle is through the carinal vessel (Figs. 1-3). In Lithotrya valentiana. Cannon (1947) described a pair of vessels in the mantle region between the terga and carina, but I doubt these are homologous to the carinal vessel of the Lepadidae, which is unpaired. The carinal vessel extends the full length of the carina, and gives off smaller vessels along its entire length. Almost all of the tergal area and a good portion of the scutal area of the mantle is supplied by this vessel.
In lepadids, the ovigerous frena (Figs. 1, 2) are highly vascularized with a circulation similar to the rest of the mantle. A vessel, connecting the scutal vessel on each side of the mantle, borders the distal margin of each ovigerous frenum. In L. fasicularis, the ovigerous frena are bilobate (Fig. 2), with a large vessel extending along the distal margin of each lobe. These vessels join and the resulting vessel connects to the scutal vessels, which in turn enter the body. In contrast to the situation in P. polymerus, the mantle knobs and the circulation associated with the mantle muscles are not present in the lepadids.
The paired scutal vessels partially circle the adductor scutorum at the muscle's insertion on the two scutal plates (Figs. 1, 2) in a manner similar to that found in P. polymerus. The scutal valve (Fig. 1) lies just inside the entrance of the scutal vessel into the body.
The circulation of the mantle varies between species (Figs. 3-6), with the plexuses appearing random in L. anatifera (Fig. 6) to fairly organized in L. pectinate pacifica (Fig. 4). The mantle circulation of C. virgatum (Fig. 5) differs from Lepas in being essentially a double system in which plexuses are associated with both the external and internal cuticles of the capitulum. Scattered connections exist between these two plexuses.
In L. anatifera, the vessels between the capitular plates enlarge somewhat; in C. virgatum the plexal vessels appear uniform throughout the mantle, but enlarge as they approach the scutal vessels.
Distributive circulation. — Near the points where the adductor scutorum inserts on the scuta, the two scutal vessels enter the body from the mantle and enlarge to form the paired scutal sinuses (Figs. 7-10). In all four species, as in P. polymerus, the scutal sinuses are located on each side of the rostral sinus, in close proximity to the adductor scutorum. The precise position of the scutal sinuses varies from species to species: in L. anatifera they are mostly posterior to the adductor scutorum; in L. fasicularis they are anterior; and in L. pectinata pacifica and C. virgatum they are dorsal. Their shape and extent also varies.
The adductor scutorum receives blood from the scutal sinuses in all species. The afferent circulation to this muscle is located immediately posterior to the scutal valves. From the scutal sinuses hemolymph enters the vessels of the gut, gastric gland, and the maxillary gland.
On the gut, the gastric plexus continues around most of the cephalic portion of the gut with little variation in vessel caliber (Figs. 7-10). In the posterior part of the cephalic gut, the paired inferior gastric vessels continue from vessels of the gastric plexus. As this pair of vessels continues posteriorly, branches of the gastric gland plexus also combine with the inferior gastric vessels.
The paired inferior gastric vessels join on the ventral surface of the thoracic gut above the first pair of cirri. This combined vessel (the posterior inferior gastric vessel) continues posteriorly and descends to contact the epineural sinus by one or more
296
CEPH. TR. M.
INF GAS. VES.
CAST GL.
SUB. VES.
THOR. TR M. I
POST INF GAS VES.
EPI.SIN,
-AD SCUT
CEPH.TR. M.
INF GAS. VES.
POST INFGAS VES.
SUB. VES
EPISIN.
SCUT SIN
Figure 7. Distributive circulation as seen from the left side of the body in I. anatifera. Numbers 1-6 refer to the positions of the respective cirri.
Figure 8. Distributive circulation in L. fasicularis.
branches. In L. anatifera, the posterior inferior gastric vessel is reduced and has only one contact with the epineural sinus. In all lepadids, the epineural sinus, which surrounds the nerve cord at the base of the cirri, receives blood from two additional sources: 1) the scutal sinuses through the maxillary gland, to connect to the anterior part of the epineural sinus, and 2) a connection by the subintestinal vessel from the gastric gland
297
CEPH TR M
GAS.VES.
/NFGAS.VES.
POST SIN.
AD.SCUT
SUBVES
THORTR.M. 182
Figure 9. Distributive circulation in L. pectinata pacifica. Figure 10. Distributive circulation in C. virgatum.
plexus. Blood from the epineural sinus goes to the cirri, penis and oral cone.
In L. anatifera the subintestinal vessel originates as a pair of vessels among the plexus surrounding the gastric gland. These two vessels collect blood from the gastric gland plexus and enlarge as they descend toward the epineural sinus. The subintestinal vessel is then formed by the combining of the two vessels just anterior to the first thoracic transverse muscle. On the anterior part of the epineural sinus, the subintestinal vessel
298
enters slightly dorsal to the maxillary gland connections. In the other three species the subintestinal vessel consists of one or two short vessels connecting the gastric gland plexus to the epineural sinus.
The distributive circulation of Z.. fasicularis is more grossly constructed in contrast to L. atiatifem. The posterior inferior gastric vessel unites with the epineural sinus to form a large posterior sinus. The afferents to the oral cone, which originate from the epineural sinus, are divided into two vessels, the afferent mandibular vessel going directly to the mandibles, and the afferent oral cone vessel to the rest of the oral cone. The afferent filamentary vessels to the four filamentary appendages at the base of each first cirrus originate on the anterior-most part of the epineural sinus.
Circulatory morphology in L. pectinata paciftca appears most similar to that of L. fasicularis. The union of the posterior inferior gastric vessel to the epineural sinus is so extensive that the two make up a single sinus (the posterior sinus) posterior to the second thoracic segment. The gastric gland plexus does not extend directly around the cephalic transverse muscle and the large sinus at the base of the first cirrus is not present as it is in L. fasicularis.
The distributive system of C. virgatum is similar to that of Lepas (Fig. 10). The gut plexus is strongly directionally oriented. The connection of the posterior inferior gastric vessel to the epineural sinus is by two or three large caliber vessels. Plexal circulation of the gastric gland appears more haphazard than in L. anatifera. The dorsal part of the gastric circulation is connected to the inferior gastric vessels by a varying number of short vessels.
In P. polymenis, the cirri are too darkly pigmented to observe their circulatory morphology, but the opposite holds with the lepadids. Figure 11 shows the circulation of three segments of a ramus from L. anatifera, which is similar to that of the other species being considered here.
The afferent circulation in a ramus of a cirrus continues distally from the epineural sinus and is in close contact with the flexor muscle. In each segment of a ramus, the circumflexor muscle circulation originates from the afferent vessel and surrounds the flexor muscle in a sheet-like sinus. This circulation connects to the efferent circulation of the ramus by a steadily constricting sinus. There may be a valve at the contact point with the efferent cirral vessel. The efferent cirral vessel progresses down the outside margin of the ramus to eventually connect with the peripheral-collecting circulation.
The general morphology of circulation in the lepadid filamentary appendage is similar to that of P. polymerus (Burnett, 1972). There are two vessels (the filamentary vessels) on opposite sides of the filamentary appendage that parallel the main axis of the appendage (Fig. 12). From the afferent filamentary vessel, a sheet-like sinus arises on each side of the vessel, and each extends in a semicircle around the filamentary appendage to connect the efferent filamentary vessel.
The Lepadidae have two types of filamentary appendages: type I receives hemolymph from thq afferent circulation to the cirri; type II receives blood from the peripheral circulation and will be discussed below. Each species shows a different arrangement and number of type I filamentary appendages. Lepas anatifera has a type I appendage at the base of the first cirrus. Lepas pectinata paciftca also has one in the same location, but it is reduced. There are four such appendages in L. fasicularis, which form a star pattern where they originate at the base of first cirrus. Conchoderma virgatum has filamentary appendages of the first type at the base of the first, third, fourth and fifth cirri. Interestingly, C. virgatum has an additional filamentary appendage at the base of the first cirrus that receives blood from the efferent circulation of that cirrus (a type II filamentary appendage). This is the only case where a type II filamentary appendage occurs on a cirral base.
Peripheral-collecting circulation. (Figs. 13-18). — In P. polymenis, I described three circulations of the body: distributive, peripheral and collecting. The lepadids, however, have only two distinctive circulations of the body, the distributive and the return. In order to maintain uniformity in nomenclature, I shall call the return circulation of the lepadids the peripheral-collecting circulation. Cannon (1947) also described the return circulation
299
CIRCUMFL.M.CIRC.
0-5mm
CEPHTR.MCIRC.
TEST PL PER CIRC
ROSr VES
GAS.VES.
AD. SCUT
Figure 11. Circulation of three segments of a ramus in L. anatifera. a. View of the posteriorly facing side of the
ramus, b. anteriorly facing side.
Figure 12. A filamentary appendage from the base of the first cirrus in L. anatifera showing the circulatory pattern. This arrangement is basic to all filamentary appendages thus far observed, a. Longitudinal view, b. cross section.
Figure 13. The peripheral-collecting circulation of L. anatifera in an illustration similar to Fig. 7. The superior gastric vessel along most of its length abutts directly against the inferior gastric vessel (see Fig. 7).
300
PRO SIM
POST VAL
0-5 mm
Figure 14. Variation in the superior gastric vessel of L. anatifera. See text for description.
Figure 15. The peripheral-collecting circulation as seen from the left side of the body of/,, anatifera, a. the ln)rdcr of the prosomal sinus.
Figure 16. Close-up of the peripheral-collecting circulation of the cephalic region in L fasicularis showing the thin layer of the peripheral circulation along with the testicular plexus.
Figure 17. The rostral vessel and its associated sinuses in L. anatifera.
Figure 18. The distribution of the thin layer of muscle surrounding the prosomal sinus in C. virgatum.
301
in Lithotrya valentiana as essentially a peripheral-collecting system.
The peripheral-collecting circulation in the Lepadidae was much more difficult to trace due to the weakness of the rostral valve and a consequent filling of the prosoma with Microfil. However, in a few£. anatifera I was able to trace this circulation, although fine details were usually obscurred.
The major source of hemolymph to the peripheral-collecting circulation comes from the efferent cirral vessels and the return flow from the penis. There are two possible routes for this hemolymph after it leaves the cirri. In one pathway, vessels from the posterior cirri (5 and 6) and penis join to form the paired superior gastric vessels (Fig. 13). These vessels occupy a ventrolateral position on each side of the thoracic gut and decrease in caliber from their posterior origin. The superior gastric vessels give rise to a plexus covering almost the entire thoracic gut. Essentially the same pattern is shown in P. polvmerns (Burnett, 1972). In one individual (of five £. anatifera) the efferent circulations from the left side of cirri 2 through 6 contributed to the superior gastric vessel (which in this case was divided into two vessels; Fig. 14). On the right side, the morphology was as described above.
The efferent cirral circulation also contributes to the peripheral circulation of the thoracic region (Fig. 15). In the dorsal part of the thorax the peripheral circulation is derived from the plexus of the thoracic gut circulation. The two peripheral circulations combine and their hemolymph flows anteriorly. At the cephalic-thoracic border, a vessel emanating from the thoracic peripheral circulation enters the cephalic filamentary appendage.
There is a peripheral connection between the thoracic and cephalic peripheral circulations, but as this area is remote from the site of injection, the Microfil rarely formed a continuous band from the thoracic to the cephalic peripheral-collecting circulations. The cephalic filamentary appendage (a type II filamentary appendage), however, serves as a less resistant connection between the two halves of the peripheral- collecting circulations. The cephalic transverse muscle, in contrast to that of P. polymerus, is surrounded by hemolymph from the cephalic peripheral circulation (Fig. 13).
The peripheral-collecting system of the prosoma has two regions. In the posterior part, the circulation is divided into a plexus that surrounds the testes (the testicular plexus). This is similar to the peripheral-collecting circulation of the thoracic region. In L. fasicularis, this plexus is more grossly constructed than in L. anatifera and in both a thin peripheral circulation arises from connections with the testicular plexus.
The testicular plexus and peripheral circulation connect anteriorly to the prosomal sinus (Figs. 13, 17), which is a half bowl-shaped sinus occupying the anterodorsal part of the body. This sinus is completely covered by a thin blanket of muscle (Fig. 18) that is sandwiched between the sinus and the cuticle of the prosoma.
As in P. polymerus, the prosomal sinus is connected by a pair of round openings (the prosomal valves. Fig. 17) to the rostral vessel. The morphology of the region appears to be as in P. polymerus, except the valve flaps of the rostral vessel do not appear to be present (this is probably due to vessel distortion so frequently observed in the injections of the lepadids).
The rostral sinus (Figs. 13, 17) also has a morphology similar to that of P. polymerus. This sinus receives blood from the oral cone, the adductor scutorum, and perhaps the prosomal sinus via the rostral vessel.
By shining a light through L. fasicularis, I observed that the cuticle between the adductor scutorum and the oral cone pulsates every 3-4 seconds at 22°C. Such movements probably result from the contraction of the rostral sinus muscles. However, for the rostral sinus to operate as a pump, a valve should be located between the rostral sinus and the anterior oral cone; none was found.
It appears that the rostral sinus pumps hemolymph through the rostral vessel and into the peduncle. The direction of flow is deduced from the position of the valves, partial injections of Microfil, and from my studies with P. polymerus (Burnett, 1972).
302
0(pr.)
CARDVAL ...„.-.,..- ...™^..,.
ROSTVAL. ROSTSIN. \ ^PRQVAL.(pr)
Figure 19. Comparison of the rostral vessel (right) with the heart of Calanus finmarchicus (left — redrawn from
Lowe. 1935).
The structure of the vessel wall of the cephalic gut is like that of the midsagittal vessels in P. polymenis. Light microscopy shows an intima containing large branching fibers that become more diffuse a short distance from the intima. The spaces with no apparent circulation ventral to the gut are occupied by the seminal vesicles. These organs appear to have little circulation associated with them.
The distributive circulation of the four species differs in vessel number and caliber: the smaller species {L. fasicularis and L. pectinata pacifica) have fewer, larger caliber vessels than the larger species, suggesting that small barnacles have less complex circulation. Conchodenna virgatum and L. fasicularis are of similar size, but the former has more complex circulation.
The blood pump. — The location of the hemolymph pump in barnacles has been in dispute (Fyhn et al., 1973). From a study of serial sections of Lithotrya valentiana. Cannon (1947), placed it between the adductor scutorum and the base of the oral cone (the rostral sinus). He called this sinus the "blood pump" instead of a heart because the muscles are located within the sinus rather than encircling it. In Balanus balanoides, Gutmann (1960) argued that circulation takes place as a result of muscular activity or during cirral extension and retraction: during periods of inactivity contraction of muscles in the prosoma propel the blood. However, in inactive barnacles Blatchford (1970) observed movements in the region of the rostral sinus that he ascribed to circulatory movements.
I found by my observations on L. fasicularis that the rostral sinus probably acts as a blood pump for this species and for the other lepadid species.
DISCUSSION
Newman et al. (1969) postulated that the thoracican Cirripedial were derived from an ascothoracican-like maxillopodian ancestor and therefore are closely allied to the Copepoda. I noted (1972) the similarity of the heart of the copepod Calanus finmarchicus to the rostral vessel of P. polymerus (Fig. 19). The lepadid rostral vessel with its connection to the prosomal sinus has the same arrangement as in P. polymerus. The argument supporting the rostral vessel as being a vestigial heart is 1) the rostral vessel is essentially in a dorsal position and is properly oriented, 2) the openings into the rostral vessel correspond to the positions of the ostia in the copepod Calanus finmarchicus (Lowe, 1935), and 3) the rostral valve is homologous to the cardioarterial valve in the copepod heart.
Since the rostral vessel lacks musculature, I infer that during the evolution of the Cirripedia, heart function was shifted from the heart (rostral vessel) to the rostral sinus (an original part of the pericardial sinus). Why would there be a shift of heart function in the barnacles? In pedunculate barnacles contraction of the peduncle forces a large pulse of hemolymph into the body. Apparently, the only large sinus positioned to receive and store this extra hemolymph is the prosomal sinus. The prosomal sinus probably not only acts as the main venous sinus for the body, but also is involved in maintaining equilibrium between the peduncle and the body.
In the primitive thoracic cirriped, the heart was suspended in a sinus that was subject to increasingly high pressures as the peduncle became more dynamic. The net
303
effect of these increasingly high pressures would be collapse of the heart. A shift of blood pumping from the heart to a sinus where the muscles are intrinsically located would solve the problem of collapse.
The reason for splitting the primitive pericardial sinus into the prosomal and rostral sinuses is difficult to postulate. Perhaps this separation was present prior to the development of a peduncle and the consequent loss of heart musculature. Such a separation would be necessary if part of the pericardial sinus was to act as a reservoir and part as a pumping organ.
Regardless of the state of the peduncle, it must always receive oxygenated blood. This is accomplished by a continuous beating of the rostral sinus in which, no matter what the length of the peduncle, a constant volume of blood is pumped into the peduncle from the rostral sinus. Peduncular extension is probably mostly mediated by hemolymph from the prosomal sinus that was originally squeezed out of this sinus by contraction of the prosomal muscles.
ACKNOWLEDGEMENTS
I wish to thank Dr. Robert R. Hessler of Scripps Institution of Oceanography for his review of the manuscript and helpful suggestions during this study. I also wish to thank Dr. Carl Hubbs of Scripps Institution of Oceanography for supplying the Conchoderma virgatum, and Dr. William Newman of Scripps Institution of Oceanography for his review of the manuscript.
LITERATURE CITED
Blatchford, J.G.
1970. Possible circulatory mechanism in an operculate barnacle. Comp. Biochem. Physiol., 34:911-915. Burnett, B.R.
1972. Aspects of the circulatory system oi Pollicipes polymerus J.B. Sowerby (Cirripedia: Thoracica). J. Morph., 136:79-107.
Cannon, H.G.
1947. On the anatomy of the pedunculate barnacle Z,/r/iorrva. Philos. Trans. Roy. Soc. London., Proc. B 233:89-136. Fyhn, H.J., J. A. Petersen, and K. Johansen
1973. Heart activity and high-pressure circulation in Cirripedia. Science, 180:513-515. Gutmann, W.F.
1960. Funktionelle Morphologic von Balanus balanoides. Abh. senckenb. naturf. Ges., 500:561-603. Lowe, E.
1935. On the anatomy of a marine copepod Calanus finmarchicus. Roy. Soc. Edinburgh, Trans., 58:561-603. Maynard, D.M.
1960. Circulation and heart function. In. Waterman, T.H. (ed.) The Physiology of the Crustacea. I. Metabolism and Growth. Academic Press, New York. p. 161-226. Newman, W.A., V.A. Zullo, and T.H. Withers
1969. Cirripedia. In. Moore, R.C. (ed.). Treatise on Invertebrate Paleontology. Part R. Arthropoda 4. Geological Society of America, Inc. Boulder Colorado, p. 206-295.
Scripps Institution of Oceanography. P.O. Box 1529, La Jolla, California 92037.
APPENDIX ABBREVIATIONS
AD. SCUT. adductor scutorum
AF. AD. SCUT. afferent of the adductor scutorum
AF. CIR. VES. afferent cirral vessel
AF. FIL. VES. afferent filamentary vessel
AF. MAN. CIRC. afferent mantle circulation
AF. MD. afferent mandible circulation
AF. OR. C. VES. afferent oral cone vessel
AN. anus
ANT. OR. C. VES. anterior oral cone vessel
304
CAR.
CAR. VES.
CARD. VAL.
CEPH. FIL. AP.
CEPH. PER. CIRC.
CEPH. TR. M.
CEPH. TR. M. CIRC.
CIR. 1
CIRCUM. FL. M. CIRC.
CON. VES.
carina
carinal vessel
cardioarterial valve
cephalic filamentary appendage
cephalic peripheral circulation
cephalic transverse muscle
cephalic transverse muscle circulation
cirrus 1
circumflexor muscle circulation
connective muscle
EF. CIR. VES. EF. FIL. VES. EPI. SIN. EX. CUT.
efferent cirral vessel efferent filamentary vessel epineural sinus exterior cuticle
FIL. AP.
filamentary appendage
|
G. |
gut |
|
CAST. GL. |
gastric gland |
|
GAST. PL. |
gastric plexus |
|
INF. GAS. VES. |
inferior gastric vessel |
|
IV. CIRC. |
intervalve circulation |
|
M. |
mantle |
|
MAX. GL. PL. |
maxillary gland plexus |
|
O. |
ostium |
|
O. (pr) |
ostium (paired) |
|
OR. C. |
oral cone |
|
OV. FR. |
ovigerous frenum |
|
P. |
penis |
|
PED. |
peduncle |
|
PED. VES. |
peduncular vessel |
|
PER. CIRC. |
peripheral circulation |
|
POST. INF. GAS. VES. |
posterior inferior gastric vessel |
|
POST. OR. C. VES. |
posterior oral cone vessel |
|
POST. SIN. |
posterior sinus |
|
PRO. M. |
prosomal muscle |
|
PRO. SIN. |
prosomal sinus |
|
PRO. VAL. |
prosomal valve |
|
PRO. VAL. (pr) |
prosomal valve (paired) |
|
ROST. M. |
rostral muscle |
|
ROST. SIN. |
rostral sinus |
|
ROST. VAL. |
rostral valve |
|
ROST. VES. |
rostral vessel |
|
SCUT. PL. |
scutal plexus |
|
SCUT. SIN. |
scutal sinus |
|
SCUT. VAL. |
scutal valve |
|
SCUT. VES |
scutal vessel |
|
SUB. VES. |
subintestinal vessel |
|
SUP. GAS. VES. |
superior gastric vessel |
|
SUR. CIRC. |
surface circulation |
|
TER. PL. |
tergal plexus |
|
TEST. PL. |
testicular plexus |
|
THOR. FIL. AP. |
thoracic filamentary appendage |
|
THOR. PER. CIRC. |
thoracic peripheral cjrculation |
|
THOR. TR. M. |
thoracic transverse muscle |
VAL.
valve
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