NUMBER 274
DECEMBER 23, 1975

IVJH"

DESCRIPTIONS OF
NEW CHILEAN ANT TAX A
HYMENOPTERA: FORMICIDAE)

By Roy R. Snelling

NATURAL HISTORY MUSEUM OF LOS ANGELES COUNTY

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DESCRIPTIONS OF NEW CHILEAN ANT TAXA
(HYMENOPTERA: FORMICIDAE)1

By Roy R. Swelling2

Abstract: One new species of Solenopsis, dysderces, is described. Two
species, bidentatus Mayr and denticulatus Mayr, are removed from the genus
Nothidris. A new species of Nothidris , cekalovici, is described and Megalomyrmex
bicolor Ettershank is transferred to Nothidris. A key is given for the known
species of Nothidris. A new genus, Antichthonidris (type species: Monomorium
denticulatum Mayr 1887), is proposed for the two species removed from
Nothidris.

The status of the two genera Dorymyrmex and Araucomyrmex is briefly dis-
cussed. A new species, agallardoi , of Dorymyrmex is described from Santiago
Province. The following new species of Araucomyrmex are described: hunti (An-
tofagasta Prov.), hypocritus (Santiago Prov.), incomptus (Coquimbo Prov.), pap-
podes (V alparaiso Prov.) and pogonius (Nuble Prov.).

All new taxa are illustrated. Primary types of new species are in the Natural
History Museum of Los Angeles County (LACM), with paratypes of most in the
Museo Nacional de Historia Natural, Santiago, and Universidad de Concepcion,
Concepcion.

INTRODUCTION

A general taxonomic and ecological review of the ant fauna of Chile is now
nearing completion. The following new taxa are described in order that the names
may be available for use in that study in which all new and old taxa in the
Chilean fauna will be separated by keys.

Most of the material for the present paper was collected by J. H. Hunt and
deposited in the Natural History Museum of Los Angeles County (LACM). Im-
portant material from the collections of the Museo de Historia Natural de San-
tiago (MSTO) and from the collection of T. Cekalovic, Universidad de Concep-
cion, Concepcion (UCON), was also available. These institutions graciously have
assented to deposit of primary types, based on their material, in the LACM;
paratypic material will be deposited in all three collections.

The descriptions which follow utilize morphological terminology conven-
tional in formicid taxonomy. The number in parenthesis following a measure-
ment or index indicates the appropriate figure for the holotype or, in one case, the
allotype. All measurements are in millimeters.

'Review Committee for this Contribution
J. C. Hall
Charles L. Hogue
P. H. Timberlake

2Section of Entomology, Natural History Museum of Los Angeles County, Los Angeles,
California 90007

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MYRMICINAE
SOLENOPSIS Westwood
Solenopsis dysderces new species
Figures 1-2

Diagnosis. Worker: Size minute, HL less than 0.5 mm; apical antennomere
longer than segments 2-8 combined; eye a single unpigmented facet; frontal punc-
tures fine, sparse. FEMALE and MALE unknown.

WORKER. Measurements. HL 0.40-0.44 (0.44); HW 0.31-0.32 (0.32); SL
0.28-0.31 (0.30); WL 0.44-0.46(0.45); PW 0.19-0.21 (0.20).

Head (fig. 1 ). Distinctly longer than broad, Cl 70-76 (73), sides approximate-
ly parallel, slightly convergent above, occipital margin slightly concave. SI 87-98
(94), apex of scape short of occipital margin by about twice maximum diameter of
scape; apical antennomere 1 .20- 1 .30 ( 1 .27) times combined lengths of segments 2-
8. Eye unpigmented and barely discernible, consisting of a single facet. Clypeus
with distinct carinal and paracarinal teeth projecting beyond apical margin. Man-
dibular formula 1+3, basal tooth distinctly displaced basad on upper margin.

Thorax (fig. 2). Slender, PW 0.44-0.46 (0.45) x WL. Thoracic dorsum, in
profile, flattened; metanotal groove distinctly and sharply impressed.
Propodeum, in profile, without differentiated basal and posterior faces.

Petiole, in profile, robust, anterior peduncle short; anteroventral tooth pres-
ent, but small. Postpetiole, in profile, with node low, rounded. In dorsal view,
nodes of petiole and postpetiole about equally broad.

Vestiture. Head, thorax and petiole with sparse, irregularly spaced erect hairs
of variable length. Scape and tibiae with conspicuous short erect to suberect
hairs.

Integument. Smooth and shiny. Frons with scattered fine punctures,
separated by 4 x or more, a puncture diameter, hardly exceeding in diameter the
hairs arising from them. Frontal lobe without conspicuous striae. Clypeus with
bicarinate median lobe, otherwise unsculptured. Mandible with sparse fine punc-
tures. Mesopleura without punctures or striae. Side of propodeum with two or
three inconspicuous fine striae below.

Color. Pale yellowish, mandibular teeth, clypeal margin and thoracic sutures
reddish.

FEMALE and MALE unknown.

Type Material. Holotype and five worker paratypes: CHILE, Prov. Acon-
cagua: ca. 3 km north of Zapallar, 28 Oct. 1972 (J. H. Hunt, #JHH 958). All type
material in LACM.

Etymology. Gr., dysderkes, hardly seeing, so named because of the reduced,
unpigmented eye.

Ecology. The few specimens known were removed from a small cell about 15
cm below the surface of the soil, while excavating a colony of Araucomyrmex.

The depigmentation, reduced eyes and minute size suggest that this species is
probably entirely subterranean and may be associated with other ant species
through cleptobiosis.

Discussion. This ant belongs to the group recognized formerly as the sub-

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Descriptions of New Chilean Ant Taxa

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genus Diplorhoptrum , synonymized recently with Solenopsis by Ettershank
(1966). Its affinities are uncertain, but the minute size, elongate tenth anten-
nomere and reduced eye are suggestive of S. pygmaea Forel, an Antillean species.
The latter ant is known to me only from the original description, which is suf-
ficiently imprecise that no clear-cut distinction can be made at this time. I con-
sider it unlikely, however, that the two are the same and have elected to describe
the Chilean species as new.

The only other Chilean Solenopsis in which the tenth antennomere exceeds
the combined lengths of segments 2-8 is S. Helena Emery. In that species the eye is
pigmented and consists of three or four facets. The punctures on the frons are two
to three times the diameter of the hairs arising from them and are separated by
two to three times their own diameter. The median clypeal lobe is more abruptly
produced in S. helena and the node of the postpetiole, in profile, is more strongly
elevated.

NOTH IDRIS Ettershank

Nothidris was established by Ettershank (1966) for three Chilean species as-
signed previously to Monomorium. The designated type species was M. latastei
Emery, 1895. The two other included species were N. bidentatus (Mayr) and N.
denticulatus (Mayr). Ettershank was unable to study the sexual forms of any of
the species. Both sexes of all three species have been available to me and I am cer-
tain, after studying these, that the genus, as orginally constituted, is an unnatural
one. I am removing N. bidentatus and N. denticulatus to a new genus, described
below. Further, Megalomyrmex bicolor Ettershank, 1965, is transferred to
Nothidris and one new species is described here.

Although Ettershank felt M. bicolor to be related to such Megalomyrmex
species as M. goeldii Forel, I cannot agree that this is the case. In species of that
group, the median lobe of the clypeus is not bicarinate, the head is more nar-
rowed above than below, the antepenultimate and penultimate antennomeres are
much longer than wide, the propodeal profile is different and the petiolar and
postpetiolar nodes are much lower in profile. In all of these characters M. bicolor
is very similar to N. latastei ; the undescribed female of M. bicolor is also very
much like that of N. latastei. The transfer of Megalomyrmex bicolor to Nothidris
is a NEW COMBINATION.

Nothidris cekalovici new species
Figures 3-4

Diagnosis. Worker: Propodeum broadly rounded, without sharp projections;
head narrow, Cl 82-88; malar area no longer than maximum eye length;
penultimate antennomere 1.2-1. 5 times longer than wide. FEMALE and MALE
unknown.

WORKER. Measurements. HL 0.86-1.10 (1.10); HW (excluding eyes,
measured at level of top of eye) 0.71-0.96 (0.92); SL 0.78-0.99 (0.97); WL 1.13-
1.48(1.48); PW 0.51-0.71(0.71).

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Head (fig. 3). Distinctly longer than broad. Cl 82-88 (84); in frontal view,
sides approximately parallel in middle and convergent above and below; occipital
margin nearly flat. Scape short, SI 103-1 1 1 (106); penultimate antennomere 1.2-
1.5 (1.3) times longer than wide. Eye large, maximum diameter about 1.5 times
minimum diameter; OMD 0.79-1.00 (0.95) x EL. Clypeus weakly longitudinally
sulcate, sides of median lobe weakly carinate; median setae present; one pair in-
tercarinal setae; first pair paracarinal setae shorter; a few lateral setae present.
Dental formula 1 +4. Palpal formula 4, 3.

Thorax (fig. 4). Of normal worker form for this genus, PW 0.43-0.48 (0.48) x
WL. Promesonotum, in profile, strongly convex, abruptly sloping behind;
promesonotal suture distinct to spiracle, above which and across dorsum, it is
very faint. Metanotal groove distinctly impressed dorsally and on side.
Mesothoracic dorsum, seen from above, distinctly narrowed behind. Propodeum
longitudinally impressed; juncture of basal and posterior faces broadly rounded,
not at all angulate. Propodeal spiracle small, round. Inferior propodeal plates
large, with distinct angulation above! Metapleural gland large, distinct; postero-
ventrally with rounded protuberance bearing gland opening.

Nodes of petiole and postpetiole high, summits rounded in profile. Anterior
peduncle of petiole ventrally carinate, carina ending truncately in front. Gastric
profile biconvex.

Vestiture. Head, thorax and gaster with sparse, fine, long white hairs; scape
with much shorter, suberect hairs; hairs appressed to subappressed on tibial ex-
tensor surfaces.

Integument. Entire ant smooth and shiny. Median lobe of clypeus bicarinate
and with 1-3 short rugulae at side; a few fine rugulae in antennal fossa; malar area
with distinct, coarse rugulae; mandible coarsely rugulose; mesokatepisternum
with numerous fine, diagonal striae, some faint; metapleuron with a few short,
coarse rugulae.

Color. Thorax, petiole, postpetiole, and legs (except basitarsi) light yellowish
to light reddish; head, gaster and basitarsi light brown. Mandibles reddish yellow,
teeth blackish.

FEMALE and MALE unknown.

Type Material. Holotype and 21 worker paratypes: CHILE, Prov. Acon-
cagua: Carretera Panamericana, km 206, 10 km north of Pichidangui, 23 Dec.
1963 (T. Cekalovic, No. 4174). Holotype and seven paratypes in LACM; 11
paratypes in UCON: three paratypes in MSTO.

Etymology. This species is dedicated to Tomas Cekalovic K., collector of the
type series and many other fine samples of Chilean ants.

Discussion. The color pattern will serve to separate N. cekalovici from the
other described species. Four specimens from Algarrobo, Valparaiso, 21 July
1951 (Kuschel and Pena; MSTO) resemble N. cekalovici in color pattern. These
were recorded by Kempf (1970) as Megalomyrmex bicolor. Aside from the dark
head and slightly more angulate propodeum they are very similar to N . bicolor
and may represent a distinctive color phase of that species. These specimens differ
from N. cekalovici in the sharply angulate propodeum and long malar area.

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Descriptions of New Chilean Ant Taxa

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The three recognized species of Nothidris may be separated by the following
key to the workers.

1. Head concolorous with thorax, gaster darker (if head is concolorous with gas-
ter, malar area is at least 1.10 x EL); propodeum distinctly angulate or with

sharp projections 2

Head concolorous with gaster, thorax paler; malar area 0.79-1.00 x EL;
propodeum rounded, not at all angulate at juncture of basal and posterior
faces cekalovici Snelling

2. Propodeum angulate, but without sharp projections; penultimate anten-
nomere 1.25-1.45 x longer than wide; malar area usually 1.2 or more x

EL bicolor (Ettershank)

Propodeum at least sharply angulate, usually with distinct sharp projections;
penultimate antennomere 0.77-1.20 x longer than wide; malar area usually less
than 1.2 x EL latastei (Emery)

AMTICHTHONIDRIS new genus

Diagnosis. Monomorphic: Median lobe of clypeus bicarinate, prolonged
over apical margin in worker and female. Palpal formula, female and worker, 2,
2; male, 3, 2. Anterior tentorial pit about midway between antennal socket and
lateral margin of clypeus. Male scape longer than third antennomere. Propodeum
dentate or spinose. Promesonotum of worker, in profile, weakly convex or flat-
tened. Mid and hind tibial spurs absent.

Type Species. Monomorium denticulatum Mayr, 1887, by present designa-
tion.

WORKER. Monomorphic, size variation small. Eye well developed, placed
slightly below middle of side of head; ocelli absent. Antenna twelve-segmented,
with well-defined three-segmented club; scape simple at base, its apex not ex-
ceeding occipital margin. Palpal formula 2, 2 {\slp2>, H2). Dental formula 1+4,
mandible normal in A. denticulatus', modified in A. bidentatus', canthellus not
meeting basal margin and trulleum distinct and open in A. denticulatus, both
modified and reduced in A. bidentatus. Labrum cleft. Clypeus bicarinate (A. den-
ticulatus) or flattened and modified (A. bidentatus, fig. 5.), apex of median lobe
exceeding apical margin; median and paracarinal setae present. Promesonotum
moderately convex ( A . denticulatus) or flattened (+. bidentatus ); promesonotal
suture as in Nothidris. Metanotal groove distinct (A. denticulatus) or weak (+.
bidentatus , fig. 6.). Middle and hind tibiae without apical spurs. Propodeum den-
tate or short-spinose. Propodeal spiracle round. Petiole distinctly pedunculate;
nodes high and rounded in profile. Anterior and posterior subpostpetiolar
process distinct.

FEMALE. Slightly larger than worker and similar except in possessing
female thoracic segmentation. Forewing with M arising from Rs+M much
anterior to r; cu-a meeting A at approximately right-angle, A continued beyond
juncture.

MALE. Size similar to worker. Clypeus strongly convex. Mandible well

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developed, apex bidentate (fig. 9). Antenna thirteen-segmented, scape short, little
longer than third antennomere; antennomeres elongate. Palpal formula 3, 2.
Vertex strongly elevated above top of eye. Notauli and parapsides present, dis-
tinct (figs. 10, 11). Wings as in female. Petiole stoutly pedunculate; petiolar and
postpetiolar nodes low, rounded in profile. Genitalic capsule fully retractile;
parameres thickened, rounded apically.

Included Names.

bidentatus (Mayr 1887) {Monomorium). Chile, Argentina.
denticulatus (Mayr 1887) ( Monomorium ). Chile, Argentina.

= navarinensis (Forel 1904) {Monomorium denticulatum var.)

= piceus (Emery 1905) (Monomorium denticulatum var.)

Etymology. Gr., antichthon (southern hemisphere) + idris (the provident
one, i.e., an ant).

Discussion. The two species included in this genus were originally described
in the genus Monomorium', Emery (1915) placed them in his subgenus
Notomyrmex. The Old World Notomyrmex , including the type species, were
transferred to the synonymy of Chelaner by Ettershank (1966) who proposed the
new genus Nothidris for the American species. However, the two species here
placed in Antichthonidris have little in common with the type species of Nothidris.

The wing venation of the sexual forms, the longer scape of the male and the
presence of distinct notauli on the male scutum require that these species be
removed from Nothidris. The correct systematic placement of Antichthonidris is
uncertain, but it is evident that these ants do not belong among the Monomorium-
Solenopsis series of genera, since males of these groups lack notauli. The wing
venation, clypeal form, lack of apical spurs on the middle and hind tibiae, and
worker habitus are suggestive of Stenamma in the Pheidolini, but the male
habitus is quite different. It seems best to leave Antichthonidris unassigned until
all myrmicine genera can be re-evaluated.

DOLICHODERINAE
DOR YMYRMEXMayr

I am here using Dorymyrmex in the restricted sense suggested by Kempf
(1972); i.e., the subgenera Dorymyrmex, Psammomyrma and Spinimyrma, but ex-
cluding Ammomyrma. Ammomyrma, ranked as a subgenus of Dorymyrmex by
Kusnezov (1952) should, in my opinion, be transferred to Araucomyrmex. The
latter group was also regarded as a subgenus by Kusnezov (1952), but later
elevated to generic status by the same author (1959). Ammomyrma agrees with
Araucomyrmex in thoracic and palpal structure.

Dorymyrmex agallardoi new species
Figures 12-13

Diagnosis. Worker with prominent, posteriorly directed propodeal spine;
side of propodeum with coarse, widely spaced rugulae; occiput densely punc-
tulate. FEMALE and MALE unknown.

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Descriptions of New Chilean Ant Taxa

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Figures 1-6. Head in frontal view, head and thorax in lateral view, of worker: 1-2,
Solenopsis dysderces. 3-4, Nothidris cekalovici. 5-6, Antichthonidris bidentatus.

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Figures 7-10. Head in frontal view, head and thorax in lateral view, of male: 7-8, Nothidris
latastei. 9-10, Antichthonidris bidentatus\ 1 1, A. bidentatus , mesoscutum of male.

WORKER. Measurements. HL 1.05-1.22 (1.19); HW 0.92-1.06 (1.04); SL
1 .08- 1 .23 ( 1 . 1 7); PW 0.60-0.69 (0.69); WL 1 .73- 1 .99 ( 1 .98).

Head. Distinctly longer than broad, Cl 87-91 (87); HL a little less than to a
little more than SL; SI 1 10-1 18 (112). In frontal view, HW greatest a little below
midpoint, sides of head slightly convex; occipital margin distinctly concave.

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Scape extending beyond occipital margin by about one-third its length. Apical
margin of clypeus gently, evenly convex in frontal view. Eye on front of head,
OMD 0.97-1.04 ( 1.04) x EL.

Thorax. Slender, PW 0.33-0.37 (0.35) x WL. From above, pronotum about
twice as wide as mesonotum, about 1.3 x propodeum. In profile, meso- and
metanota forming a continuous, steep slope from pronotum to propodeum, inter-
rupted only by sharply projecting spiracles; posterior margin of metanotum
depressed well below dorsal level of propodeum, so that anterior margin of
propodeum is abruptly declivitous. Propodeal spine, from above, nearly parallel-
sided, apex rounded; in profile, flattened and sharp at apex, base below upper
level of propodeal dorsum, directed caudad. In profile, node of petiole with
anterior face nearly vertical, dorsal face convex, posterior face strongly sloping;
without ventral spines or teeth.

Vestiture. Erect setae general but sparse, variable in length on head, thorax
and gaster; those of scape abundant, short, fine; those of tibiae long, acuminate.

Integument. Front of head mostly moderately shiny, lightly shagreened;
malar area duller, more closely shagreened; occiput and vertex dull, closely punc-
tulate; head with scattered, setigerous punctures, more numerous on occiput.
Pronotum shinier than front of head, with scattered setigerous punctures.
Pronotal neck and entire meso-metanotum dull, densely punctulate. Propodeal
dorsum similar, but sides slightly shiny and with widely spaced, oblique rugulae.
Posterior face of node of petiole with delicate, concentric striae which may be
more or less obsolete. Gaster smooth and shiny.

Color. Head and thorax dull reddish; antenna and legs medium brown; gas-
ter blackish.

FEMALE and MALE unknown.

Type Material. Holotype and four paratype workers: CHILE, Prov. San-
tiago: El Alfalfal, 25 Jan. 1968 (J. Moroni); five paratype workers: CHILE, Prov.
Santiago: San Jose de Maipo, 29 Nov. 1969 (L. Alfaro). Holotype and two
paratypes in LACM; Five paratypes in MSTO; two paratypes in UCON.

Etymology. This species is dedicated to the late Angel Gallardo, a pioneer in
the systematics and biology of South American ants.

Discussion. This is very likely the same species that Berg (1890) recorded
from Santa Rosa de los Andes, Aconcagua, Chile, as planidens Mayr. Although it
does resemble planidens in stature, the distinctly rugulose propodeal sides will
separate it from that species. The red color is also much less bright than in
planidens.

ARA UCOMYRMEX

This genus, as I interpret it, includes those species listed by Kempf ( 1972) un-
der Araucomyrmex plus most of those included in the subgenus Ammomyrma of
Dorymyrmex. I have seen most of the species placed in Ammomyrma , including
the type species, exsanguis Forel; they are all Araucomyrmex , except for em-
maericaellus Kusnezov, which is a true Dorymyrmex. Those species which I have
not seen appear from their descriptions to be Araucomyrmex also.

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Araucomyrme x hunti new species
Figures 14-15

Diagnosis. Worker: Dark brown to black; upper setae of psammophore
below level of occipital foramen; frons conspicuously more shiny than occiput;
propodeal tubercle high, acute; Cl 77-84. FEMALE and MALE unknown.

WORKER. Measurements. HL 0.77-0.92 (0.88); HW 0.60-0.72 (0.70); SL
0.80-0.97 (0.90); PW 0.40-0.50 (0.50); WL 1 .03- ! .23 ( 1 . 1 7).

Head. Conspicuously longer than broad. Cl 77-84 (79); in frontal view,
widest at eye level, usually distinctly sinuate below eye level; occipital margin
evenly convex. Scape about as long as head, SI 119-133 (129); extending beyond
occiput by about 0.3 x its length. Eye large, OMD 0.86-1.17 (1.17) x EL. Apical
margin of clypeus, in frontal view, slightly convex, weakly emarginate in middle.

Thorax. Slender, PW 0.38-0.43 (0.43) x WL. Mesonotum, in profile, straight
or slightly convex, not angulate beyond middle. Propodeum, in profile, not
depressed in front of tubercle; tubercle high, acute.

Vestiture. Head with sparse, appressed, whitish pubescence; thorax and gas-
ter with appressed pubescence longer and a little denser; some cephalic
pubescence, especially on frons may be decumbent; that of scape decumbent to
erect.

Cephalic setae sparse, on face limited to clypeus and frontal lobes, none on
occiput or vertex. Basalmost setae of psammophore below level of occipital
foramen. Pronotum usually with a single pair of erect setae, which are shorter
than apical width of scape; mesonotum and propodeum without erect setae. First
gastric tergum with irregularly spaced, long, erect setae across summit of basal
face and a row along posterior margin; remaining terga with sparse longer hairs.
Scape without erect setae. Fore femur with three or four widely spaced setae
along basal half of ventral margin; mid and hind femora without erect setae on
dorsal margin; tibiae without setae.

Integument. Clypeus moderately shiny, closely shagreened except along
midline; frontal lobes and frons moderately shiny, lightly shagreened and with
scattered micropunctures; vertex and occiput sharply duller, closely shagreened
and with numerous micropunctures. Thorax similar to occiput, closely
shagreened and with numerous micropunctures. Gaster moderately shiny, less
closely shagreened than thorax, with numerous micropunctures and scattered
coarser punctures.

Color. Dark brown to blackish; antenna and legs lighter.

FEMALE and MALE unknown.

Type Material. Holotype and 41 paratype workers: CHILE, Prov. An-
tofagasta: 2 km E Paposo, 300 m elev., 16 Nov. 1972 (J. H. Hunt, § 994). Holotype
and most paratypes in LACM; three paratypes each in MSTO and UCON.

Etymology. This species is dedicated to James H. Hunt, who collected
numerous ant samples in Chile at my request.

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Figures 12-17. Head in frontal view, head and thorax in lateral view, of worker: 12-13,
Dorymyrmex agallardoi. 14-15, Araucomyrmex hunti. 16-17, A. hypocritus. All figures to
same scale.

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Araucomyrme x hypocritus new species
Figures 16-17

Diagnosis. Worker: Bicolored species with wholly ferruginous thorax; upper-
most setae of psammophore below occipital foramen; occipital sculpture not
sharply differentiated from that of frons; mesonotum, in profile, straight over
posterior one-half; terga pubescent at sides. FEMALE and MALE unknown.

WORKER. Measurements. HL 1.03-1.08 (1.08); HW 0.83-0.92 (0.92); SL
1 . 1 7- 1 .23 ( 1 .23); PW 0.57-0.62 (0.60); WL 1 .43- 1 .57 ( 1.57).

Head. Conspicuously longer than broad, Cl 81-85 (85); in frontal view,
widest at eye level, slightly sinuate below eye level; occipital margin nearly flat in
frontal view. Scape distinctly longer than head, extending beyond occipital
margin by about 0.45 x its length; SI 134-140 (135). Eye large, OMD 1.06-1.25
(1.25) x EL. Apical margin of clypeus, in frontal view, nearly straight, with barely
indicated median sinuosity.

Thorax. Slender, PW 0.38-0.41 (0.38) x WL. Mesonotum, in profile, nearly
straight, not angulate beyond middle. Propodeum, in profile, not depressed in
front of tubercle; tubercle high, acute.

Vestiture. Appressed pubescence short, sparse on fronsg denser on occiput;
longer and denser on thorax; long and dense on gastric terga, including sides of
first two segments; very scattered around antennal sockets and on sides of head;
completely appressed on scape.

Clypeus with long setae on apical margin and a few on basal margin, disc
with a few very short setae; frontal lobes with a seta pair near clypeal base and
another at level of lower eye margin, the latter notably long; vertex with a single
pair of short setae (apparently broken off in some specimens). Basalmost setae of
psammophore below level of occipital foramen. Pronotum with a median seta
pair and a preapical, much shorter pair; mesonotum and propodeum without
erect setae. First tergum with a few scattered setae on posterior half of dorsal
face; remaining terga with preapical seta row and a few, inconspicuous discal
setae. Scape without setae except at apex. Fore femur with three or four setae on
basal half of ventral margin; mid and hind femora without setae on dorsal
margin; tibiae without setae.

Integument. Clypeus smooth and shiny along midline, closely shagreened
and moderately shiny elsewhere; frontal lobes and frons slightly shiny, closely
shagreened and micropunctate; vertex and occiput a little duller and more densely
micropunctate, out blending into frons; malar area and gena shiny, lightly
shagreened. Thorax similar to occiput, closely shagreened and moderately shiny,
sides shinier. Gaster dull, very closely shagreened and with dull micropunctures.

Color. Head, including scape, and thorax bright ferruginous; gaster blackish;
flagellum and legs dark brown.

FEMALE and MALE unknown.

Type Material. Holotype and four paratype workers: CHILE, Prov. San-
tiago: Fundo Santa Laura, near Cuesta la Dormida, 20 Oct. 1971 (J. H. Hunt,
#453), all in LACM.

Etymology. The Latin, hypocritus , mime or dissembler, because of the
similarity to such species as goetschi and tener.

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Descriptions of New Chilean Ant Taxa

13

Araucomyrmex incomptus new species
Figures 18-19

Diagnosis. Worker: Blackish, head more or less ferruginous; basalmost setae
of psammophore below occipital foramen; vertex and occiput dull, sharply dif-
ferentiated from shiny frons; basal face of propodeum, in profile, distinctly
impressed in front of low, obtuse tubercle. FEMALE and MALE unknown.

WORKER. Measurements. HL 0.72-0.80 (0.78); H W 0.60-0.65; SL 0.73-0.80
(0.77); PW 0.40-0.43(0.43); WL 0.97-1.03(1.03).

Head. Conspicuously longer than broad, Cl 79-85(81); sides, in frontal view,
widest at eye level, weakly sinuate below eye level or not sinuate; occipital margin
flattened or very weakly convex in frontal view. Scape about as long as head, SI
121-128 (123), extending beyond occiput by about 0.25 x its length. Eye large,
OM D 1 .00- 1 .08 ( 1 .00) x EL. Apical margin of clypeus, in frontal view, straight or
weakly concave in middle.

Thorax. Slender, PW 0.40-0.43 (0.42) x WL. Mesonotum, in profile, evenly
convex, not angulate beyond middle. Propodeum, in profile, distinctly depressed
in front of tubercle; tubercle low, obtuse.

Vestiture. Pubescence short, scattered on most of head, conspicuous only on
vertex and occiput; thoracic pubescence a little sparser than that of occiput; that
of gaster similar but a little longer, becoming very sparse on sides of terga.

Cephalic setae sparse; apical clypeal margin only, with long setae, those of
disc and basal margins short; frontal lobes with seta pair near clypeal base and a
longer pair at level of lower eye margin; no occipital setae; basalmost setae of
psammophore below level of occipital foramen. Pronotal disc with a single, me-
dian, seta pair; mesonotum and propodeum without setae. First gastric tergum
with a few setae at about midlength of dorsal face and a few in preapical row;
remaining terga with scattered discal and a few preapical setae. Scape without
setae except at tip. Fore femur with two or three setae on basal half of ventral
margin; mid and hind femora without setae on dorsal margin; tibiae without
setae.

Integument. Midline of clypeus smooth and shiny, remainder lightly
shagreened and moderately shiny; frontal lobes and frons moderately to very
weakly shagreened, with scattered micropunctures, moderately shiny; vertex and
occiput abruptly differentiated, closely shagreened and micropunctate, barely
shiny; malar area and side of head moderately shiny, weakly shagreened. Thorax
and gaster closely shagreened and micropunctate, slightly shiny.

Color. Head dark ferruginous, becoming lighter at sides and toward mandi-
ble, darkest (almost dark brown) on occiput; thorax and gaster blackish. Ap-
pendages dark brownish.

FEMALE and MALE unknown.

Type Material. Holotype and 11 paratype workers: CHILE, Prov. Co-
quimbo: Cerro Tololo, ca. 10 km W, 3 km S of Vicuna, 16 Oct. 1971 (J. H. Hunt,
#439); holotype and most paratypes in LACM; two paratypes each in MSTO and
UCON.

Etymology. L., incomptus , unadorned or simple, because of the reduced seta-

tion.

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Araucomyrme x pappodes new species
Figures 20-21

Diagnosis. Worker: Basalmost setae of psammophore above lower margin of
occipital foramen; front of head with numerous erect setae of various lengths on
upper half; propodeal tubercle high, sharp; thorax wholly dark brown. FEMALE
and MALE unknown.

WORKER. Measurements. HL 0.96-1.09 (1.09); HW 0.82-0.96 (0.96); SL
1 .04- 1 . 1 5 ( 1 . 1 5); PW 0. 54- 1 .00 ( 1 .00); WL 1 .4 1 - 1 .59 ( 1.59).

Head. Distinctly to a little longer than broad. Cl 85-90 (88); in frontal view,
widest at eye level, margins not sinuate below eye level; occiput, in frontal view,
flat or weakly convex. Scape distinctly longer than head, SI 118-126 (120); ex-
tending beyond occiput by about 0.3 x its length. Eye large, OMD 1.10-1.20(1.14)
x EL. Apical margin of clypeus, in frontal view, weakly subangulate in middle.

Thorax. Slender, PW 0.37-0.40 (0.38) x WL. Mesonotum, in profile, weakly
angulate beyond middle. Propodeum, in profile, weakly sinuate in front of tuber-
cle; tubercle stout, high, summit rounded, but profile acute.

Vestiture. Appressed pubescence sparse on clypeus, malar area and gena;
longer, dense, and partially obscuring surface, on frontal lobes, frons, vertex and
occiput, some hairs subdecumbent. Thoracic pubescence less dense than that of
occiput, mostly appressed, but some decumbent to suberect, especially on dor-
sum. Gastric pubescence dense, but not obscuring surface, mostly appressed, but
some hairs subdecumbent.

Cephalic setae abundant; apical margin of clypeus with very long setae, basal
margins and disc with much shorter setae; frontal lobes with apical seta pair and
another at level of lower eye margin. Frons, vertex, occiput and margins of head
with numerous short, fine setae generally distributed. Basalmost setae of psam-
mophore arising well above lower margin of occipital foramen. Pronotum with a
median pair of long (subequal to MOD), slender setae and a pair of much shorter
setae near posterior margin; disc with numerous fine, much shorter, setae.
Mesonotum with sparse, very short, fine setae. Discs of gastric terga with general-
ly distributed, short, fine setae and preapical row of longer setae. Scape with
abundant, fine, suberect to erect, very short setae. Fore femur with short, fine,
suberect to erect setae along entire ventral margin. Femora and tibiae otherwise
with generally distributed very short, fine, decumbent to erect setae.

Integument. Clypeus shiny, midline smooth and polished, remainder lightly
shagreened; malar area and gena moderately shiny, lightly shagreened, with scat-
tered micropunctures and a few coarser punctures; frontal lobes, frons, vertex
and occiput slightly shiny, sharply shagreened and densely micropunctate.
Thorax shinier than frons, less closely shagreened, about as densely micropunc-
tate. Gastric terga about as shiny as frons and similarly sculptured.

Color. Head brownish ferruginous on occiput, becoming progressively paler
toward mandible. Pronotal neck obscurely ferruginous, thorax otherwise very
dark reddish brown. Gaster blackish brown. Appendages medium brown.

FEMALE and MALE unknown.

Type Material. Holotype and 37 paratype workers: CHILE, Prov.

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Descriptions of New Chilean Ant Taxa

15

Valparaiso: Maitencillo, 30 m elev., 10 Oct. 1971 (J. H. Hunt, #424). Holotype
and most paratypes in LACM; three paratypes each in MSTO and UCON.

Etymology. Gr., pappodes, downy, in allusion to the abundance of fine
pubescence rendering to this ant its distinctive appearance.

Araucomyrmex pogonius new species
Figures 22-28

Diagnosis. Worker: Basalmost setae of psammophore above lower margin of
occipital foramen; vertex without seta pair; setae of pronotal pair less than 0.5 x
MOD; head ferruginous. FEMALE. Unknown. MALE. Cl 97-100; SI 71-77; in-
terocellar distance equal to ocellocular distance; scape shorter than head.

WORKER. Measurements. HL 0.90-0.97 (0.93); HW 0.80-0.90 (0.87); SL
0.93- 1 .03 ( 1 .00); PW 0.47-0.55 (0.53); WL 1 .20- 1 .30 ( 1 .27).

Head. Distinctly, to a little, longer than broad, Cl 88-95 (92); in frontal view,
widest at eye level, margins not sinuate below eye level; occiput, in frontal view,
weakly concave in middle. Scape slightly longer than head, SI 1 14-122 (1 15); ex-
tending beyond occiput by about 0.3 x its length. Eye large, OM D 1 .07- 1.21 (1.21)
x EL. Apical margin of clypeus, in frontal view, straight or very weakly convex in
middle.

Thorax. Slender, PW 0.39-0.43 (0.42) x WL. Mesonotum, in profile, slightly
convex, often weakly angulate beyond middle. Basal face of propodeum distinctly
sinuate in profile; tubercle high, acute.

Vestiture. Appressed, pubescence short, abundant on frontal lobes, frons
vertex and occiput; very sparse on gena and malar area; some hairs subappressed
or subdecumbent on side, above eye and on vertex. Thoracic pubescence general,
mostly appressed, but some on pronotum subappressed to subdecumbent.
Gastric terga including sides of segments with abundant appressed, and some
subappressed, pubescence.

Cephalic setae sparse, vertex pair absent. Long setae present on apical
margin of clypeus; shorter, sparse setae on disc and along basal margin; frontal
lobes with seta pair near base of clypeus and another at level of lower eye margin.
Basalmost setae of psammophore above level of lower margin of occipital
foramen. Pronotal disc with median seta pair, setae less than 0.5 x MOD.
Mesonotum and propodeum without setae. First tergum with sparse, short setae
on basal half of dorsal face and usual preapical row; remaining terga with scat-
tered, very short, discal setae and preapical row of widely spaced setae. Scape
without setae, except near tip. Fore femur with two or three setae on basal half of
ventral margin. Mid and hind femora without setae on dorsal margin. Tibiae
without setae.

Integument. Midline of clypeus smooth and shiny, remainder shiny and light-
ly shagreened; gena and malar area moderately shiny, moderately shagreened and
with scattered micropunctures; frontal lobes, frons, vertex and occiput slightly
shiny, closely shagreened and densely micropunctate. Thorax slightly shiny,
closely shagreened and densely micropunctate. Gastric terga slightly shiny, close-
ly shagreened and densely micropunctate.

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Color. Head and thorax pale ferruginous, propodeum slightly brownish.
Gaster medium to dark brownish. Antennae yellowish brown, scape paler than
flagellum; legs medium brown.

FEMALE. Unknown.

MALE. Measurements. HL 0.57 (0.57); HW 0.55-0.57 (0.57); SL 0.40-0.43
(0.40); PW 0.73-0.80 (0.73); WL 1 .43- 1 .50 ( 1 .50).

Head. As long as broad to slightly longer than broad, Cl 97-100 (100),
broadest at upper margins of eyes; occiput, in frontal view, flat, narrowly
rounded onto sides of head. Scape shorter than head length, SI 71-77 (71); apex
reaching about to occipital margin. Eye large, OMD 0.25-0.27 (0.25) x EL. Apical
margin of clypeus convex in middle. Mandible with cutting margin oblique, with
three teeth basad of apical tooth.

Thorax. Stout, PW 0.49-0.55 (0.49) x WL. Scutellum, in profile, strongly
bulging, dorsal face flat. Propodeum evenly curved in profile.

Terminalia. Apical margin of subgenital plate broadly convex to slightly con-
cave. Genital capsule (figs. 26, 27) broader than long; digitus elongate, straplike,
extending to apex of gonocoxite; ventral margin of aedeagus (fig. 28) with very
coarse teeth and a few fine teeth.

Vestiture. Appressed pubescence very sparse and inconspicuous on head.
Pubescence a little more abundant on thorax, but still sparse; longest and most
conspicuous on propodeum. Gastric terga with evenly distributed appressed
pubescence, nowhere sufficiently dense to obscure surface; sterna similarly pubes-
cent.

Clypeus with a few inconspicuous setae along apical margin and a longer
pair on either side of median lobe; frontal lobe with a pair of very short setae a lit-
tle above level of antennal sockets. Gastric sterna with a few short erect setae.
Femora and tibiae without setae. Forewing without fringe hairs; hind wing with a
few hairs on apical margin and a fringe on basal half of posterior margin.

Integument. Clypeus and frontal lobes shiny, lightly shagreened and with
scattered micropunctures; frons, vertex and occiput less shiny, lightly shagreened,
densely punctate with fine punctures of two sizes. Mesoscutum about as shiny as
frons, similarly punctate anteriorly, punctures becoming coarser posteriorly;
scutellum shiny between coarse, dense punctures; pleura similar to scutellum.
Base of propodeum shiny, lightly shagreened and with scattered, obscure punc-
tures which are finer than those of scutellum; sides less shiny, closely, finely punc-
tate. Gastric terga moderately shiny, lightly shagreened, with sparse micropunc-
tures and scattered coarser punctures.

Color. Medium brown, with anterior half of scutellum lighter; antenna and
legs light brown. Wings faintly whitish, veins and stigma yellowish to brownish
yellow.

Type Material. Holotype worker, allotype male, 35 worker and 17 male
paratypes; CHILE, Prov. Nuble; Termas de Chilian, 20 Sept. 1969 (T. Cekalovic;
#4187). Holotype, allotype, 15 worker and 7 male paratypes in LACM; 18 worker
and 9 male paratypes in UCON; 2 worker and one male paratypes in MSTO.

Etymology. Gr., pogon, -os, beard, hence bearded, pogonius, in allusion to the
long psammophore on the ventral surface of the worker head.

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Descriptions of New Chilean Ant Taxa

17

Figures 18-23. Head in frontal view, head and thorax in lateral view, of worker: 18-19,
Araucomyrmex incomptus. 20-21, A. pappodes. 22-23, A. pogonius. All figures to same scale.

0.25

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No. 274

Figures 24-28. Araucomyrmex pogonius, male. 24, head in frontal view; 25, head and
thorax in lateral view; 26, genital capsule, ventral view, with attached subgenital plate; 27,
genital capsule, dorsal view, with inflated penis; 28, aedeagus, lateral view.

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Descriptions of New Chilean Ant Taxa

19

RESUMEN

Se describe una nueva especie de Solenopsis , dysderces. Una nueva especie de
Nothidris, cekalovici, es descrito y Megalomyrmex bicolor Ettershank es
trasladado a Nothidris. Se presenta un clave para las especies conocidas de
Nothidris. Dos especies, bidentatus Mayr y denticulatus Mayr, son transferidos a
un nuevo genero, Antichthonidris, con denticulatus como la especie ti'pica.

El estado de los dos generos Dorymyrmex e Araucomyrmex es tratado en
breve. Una nueva especie, agallardoi , de Dorymyrmex es descrito de la Provincia
de Santiago. Las nuevas especies siguientes de Araucomyrmex son descritas: hunti
(Prov. Antofagasta), hypocritus (Prov. Santiago), incomptus (Prov. Coquimbo),
pappodes (Prov. Valparaiso) y pogonius (Prov. Nuble).

Todas las nuevas taxas son ilustradas. Los tipos primaries de las nuevas es-
pecies estan depositados en el LACM, con los paratipos de la mayor! a en el
Museo Nacional de Historia Natural de Santiago, y Universidad de Concepcion,
Concepcion.

LITERATURE CITED

Berg, C. 1890. Los formicidios argentinos, chilenos y uruguayos. Soc. Cient. Argent., An.
29:5-43.

Emery, C. 1915. Noms de sous-genres et de genres proposes pour la sous-famille des Myr-
micinae. Modification a la classification de ce group. Soc. Entomol. France, Bull. pp.
189-192.

Ettershank, G. 1966. A generic revision of the world Myrmicinae related to Solenopsis
and Pheidologeton. Austr. Jour. Zool. 14:73-171.

Kempf, W. W. 1970. Catalogo das formigas do Chile. Papeis Avulsos Zool., S. Paulo 23: 1 7-
43.

1972. Catalogo abreviado das Formigas da Regiao Neotropical. Studia Entomol.

15:3-344.

Kusnezov, N. 1952. El estado real del grupo Dorymyrmex Mayr. Acta Zool. Lill. 10:427-
448.

1959. Die Dolichoderinen-Gattungen von Sud-Amerika. Zool. Anz. 162:38-51.

Accepted for publication November 20, 1975.

C.-2H L 66$

NUMBER 275
JUNE 30, 1976

NOTES ON THE HERPETOFAUNA OF WESTERN MEXICO:
NEW RECORDS FROM SINALOA
AND THE TRES MARIAS ISLANDS

By Roy W. McDiarmid, Joseph F. Copp and Dennis E. Breedlove

NATURAL HISTORY MUSEUM OF LOS ANGELES COUNTY

CONTRIBUTDNS IN SCENC6

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OF LOS ANGELES COUNTY
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CONTRIBUTIONS IN SCIENCE contain articles in the earth and life sciences, presenting
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NOTES ON THE HERPETOFAUNA OF WESTERN MEXICO:
NEW RECORDS FROM SINALOA AND THE TRES MARIAS ISLANDS

By Roy W. McDiarmid* 2, Joseph F. Copp3, and Dennis E. Breedlove4

Abstract: Two species of snakes, Hypsiglena torquata and Tantilla bocourti, are
reported for the first time from the Tres Marias Islands. The salamander Ambystoma
rosaceum, the frogs Bufo cognatus and Rana tarahumarae, the lizards Eumeces
parviauriculatus , Sceloporus poinsettii, S. spinosus and S. virgatus and the snakes
Chilomeniscus cinctus, Tantilla bocourti and T. wilcoxi are added to the fauna of
Sinaloa. Each specimen is compared with individuals of the same species from other
parts of its range. These records, together with deletions of two species and notes on
six others, contribute to our knowledge of the variation, distribution and biogeography
of the herpetofauna of western Mexico.

INTRODUCTION

More is known about the distribution of the faunas of western Mexico than of any
other part of that country. This generalization is true especially of amphibians and rep-
tiles where several major works (Bogert and Oliver 1945; Duellman 1958, 1961, 1965;
Zweifel 1959, 1960; Hardy and McDiarmid 1969) have provided in-depth treatments of
the faunal composition and species distributions in this biogeographically interesting
area. As well known as the herpetofauna is, additional field work continues to produce
significant specimens. In this paper range extensions, additions and deletions to the
herpetofaunas of the Tres Marias Islands and of Sinaloa, Mexico, are reported.

Most of the material from the Tres Marias Islands was collected by James R.
Northern and Roy R. Snelling between 17 and 30 March 1964. Their expedition was
sponsored by Richard F. Dwyer of the American Foundation of Oceanography in con-
junction with the Natural History Museum of Los Angeles County (LACM). The field
party visited Isla Maria Magdalena and Isla Maria Cleofas in the Tres Marias group and
Isla Isabel, a small island located between the Tres Marias Islands and the Mexican
mainland. The new material from Sinaloa is contained in several collections that
became available after the manuscript on the herpetofauna of Sinaloa was submitted for
publication (Hardy and McDiarmid 1969). One fairly large collection was made in the
northeastern part of the state by Copp (JFC) and Breedlove during the dry seasons
between 1967 and 1971. Animals were taken at several localities at various elevations

‘Review Committee for this Contribution
Robert L. Bezy
Laurence M. Hardy
Robert G. Webb
John W. Wright

2Research Associate, Natural History Museum of Los Angeles County, and Department of

Biology, University of South Florida, Tampa, Florida 33620; 3 1441 Muirlands, La Jolla,

California 92037; department of Botany, California Academy of Sciences, San Francisco,
California 94118.

2

Contributions in Science

No. 275

and in different habitats along the road from Los Hornos (= El Omo of Gentry 1946) to
Surutato (= Surotato of Gentry) and in adjacent canyons in the remote and rugged
Sierra de Surutato. The specimens collected in Mexico by Breedlove will be deposited
in the collections of the California Academy of Sciences.

The vegetation of the Sierra de Surutato is composed of a diverse mixture of trop-
ical and temperate forest types. Gentry (1946) gave a brief description of the vegetation
and listed some major elements. At the lower elevations thorn forest and tropical
deciduous forest are common. Some elements of seasonal evergreen forests are found
in the outwashes of the major canyons such as the Canon de Tarahumare. A riparian
forest with Platanus, quite reminiscent of those found in the mountains of southern
California, Arizona and Sonora, occurs along the canyons at middle elevations. At
1000 m the tropical deciduous forest grades imperceptibly into pine-oak forest, which
at higher elevations becomes more mesic and includes Juglans and Arbutus . A forest
reminiscent of evergreen cloud forests (Breedlove 1973; mesophytic mountain forest of
Rzedowski and McVaugh 1966) occurs in a few moist, protected canyons at high
elevations. This forest is composed of several genera of broadleaf evergreen trees,
Carpinus and the conifer Pseudotsuga. The flora is characterized by a high degree
of endemism. Gentrya, a Scrophulariaceae (Breedlove and Heckard 1970), is known
to occur only here. This mountain range is also the northernmost station for many
tropical and temperate-tropical species of plants.

SPECIES ACCOUNTS
Las Tres Marias and Isabel Islands

Individuals of the following species known previously from the islands were
collected during the 1964 trip or on earlier unreported expeditions. They include
Phyllodactylus tuberculosus saxatilis, Anolis nebulosus, Ctenosaura pectinata, Masti-
godryas melanolomus slevini and Oxybelis aeneus from Maria Cleofas; Anolis nebu-
losus, Ctenosaura pectinata, Urosaurus ornatus lateralis, Cnemidophorus communis
mariarum, Boa constrictor imperator, Mastigodryas melanolomus slevini and Masti-
cophis striolatus from Maria Magdalena; and Ctenosaura pectinata, Sceloporus clarkii
boulengeri, Cnemidophorus costatus huico and Lampropeltis triangulum nelsoni
from Isabel Island. In addition to these species, three snakes are worthy of separate
consideration.

Hypsiglena torquata (Gunther). — A single specimen of this nocturnal species was
collected on Isla Maria Magdalena on 23 March 1964. The snake was moving over
a rocky beach near the water’s edge between 2200 and 2300 hours. The specimen
(LACM 25247), a female, measures 434 mm total length, of which 63 mm (12.2%) is
tail. It has the following scale characteristics: 179 ventrals, 44 subcaudals, divided
anal plate, 21-21-17 dorsal scale rows, 8-8 supralabials, 10-10 infralabials, 1-1 preocu-
lars, 2-3 postoculars, 1+2-1 +2 temporals. There are 63 body blotches and 22 tail
blotches on the dorsum; many of the dorsal blotches run together, especially on the tail.
A dark brown collar involving eight scales on the midline continues well onto the
parietal scales of the head as a thin stripe. The nuchal collar is bordered anteriorly by

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Notes on the Herpetofauna of Western Mexico

3

a narrow (1-3 scales), pale brown band that passes through the angle of the mouth.
This anterolateral extension of the band separates the brown eye stripe from the dark
collar. This pattern is more similar to “ochrorhyncha” types from Sinaloa (Hardy
and McDiarmid 1969) than to specimens from Nayarit, which have “torquata” collar
types with a wider, cream-colored band. The Tres Marias specimen also is more sim-
ilar to Sinaloa than to Nayarit specimens in ventral, subcaudal and ventral plus sub-
caudal (V +Sc) counts. The V+Sc count (222) for the Tres Marias specimen is within
the range for Sinaloa specimens (210-229; “ochrorhyncha" collar types x = 223;
“torquata" collar types x = 220) but higher than for Nayarit specimens (208-219;
x = 212, all “torquata" types).

This specimen is the first record of Hypsiglena torquata to be reported from the
Tres Marias Islands. If the Tres Marias population is related more closely to Sinaloan
populations to the north than to adjacent mainland populations, as indicated by certain
scale characteristics and color pattern, then its distribution parallels that of Urosaurus
ornatus (Zweifel 1960:118-120). Mertens (1934) pointed out that snakes from insular
populations frequently have more ventral scales than do their mainland relatives. This
same pattern was confirmed by Zweifel (1960) with respect to nearly all of the snake
species that were known then from the Tres Marias Islands. Additional material is
needed to clarify the relationship of this insular population of Hypsiglena torquata.

Leptophis diplotropis (Gunther). — The field party, collecting in a canyon on
Isla Maria Magdalena on 26 March 1964, between 1000 and 1 100 hours, found a large
specimen of Leptophis lying in a small water hole. The snake apparently was “drink-
ing.” Zweifel (1960) cited the presence of several species of snakes in close proximity
to sources of permanent water on Maria Magdalena. This record (LACM 25248) repre-
sents the first report of Leptophis diplotropis from Isla Maria Magdalena. Unfor-
tunately, the snake, which died several days later, was not preserved immediately.
Although it is in relatively poor condition the following information is available: adult
male, 189 ventrals, divided anal plate, incomplete tail, 8-8 supralabials, 9-9 infra-
labials, 1-1 loreal, 1-1 preocular, 2-2 postoculars, 1 +2-1 +2 temporals.

Tantilla bocourti (Gunther). — A single specimen of Tantilla bocourti (LACM
25251) was collected in leaf litter along a dry stream bed on Isla Maria Cleofas on
29 March 1964. This specimen is the first record of the species from the Tres Marias
and extends its known range about 240 kilometers to the west. That this is the first
report of the species from a locality lower than 1500 meters elevation and from a habitat
other than the pine and oak forests typical of many of the mainland localities is of even
greater interest.

In attempting to allocate the Tres Marias snake to a known species of Tantilla, a
large series of T. bocourti and specimens of several closely related species were
examined. The known distribution of Tantilla bocourti is shown in figure 1.

The Tres Marias specimen is an adult female differing in some respects from other
female T. bocourti. It has a slightly shorter tail and fewer ventrals and subcaudals than
the average of the specimens examined. Data in Table 1 indicate that there is sexual
dimorphism in the ratio of tail length to total length and in the numbers of ventral and
subcaudal scales. However, the mean number of ventrals plus subcaudals is essen-
tially the same for males and females. This pattern of dimorphism has been reported

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for other species of Tantilla as well (Hardy and Cole 1968; McDiarmid 1968). Other
characteristics of the Tres Marias specimen are: 15-15-15 scale rows, 1-1 preoculars,
2-2 postoculars, 1 + 1-1 + 1 temporals, a posterior temporal as wide as long (scalelike),
7-7 supralabials, 6-6 infralabials, and no contact between the mental and chinshields.
Two other specimens of T. bocourti have the mental and chinshields in contact. This
last character probably is of little value in distinguishing species of Tantilla since it is

Figure 1. Map of central Mexico showing known locality records of Tantilla bocourti (Gunther).

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Notes on the Herpetofauna of Western Mexico

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TABLE 1

Selected character states of Tantilla bocourti from the Tres Marias Islands, Sinaloa, and of other
specimens selected from localities throughout the range of the species.

Tail Length/
Total Length

Sex

in %

Ventrals

Subcaudals

V + Sc

Tres Marias

9 0)

17.6

171

45

216

Sinaloa

9 (1)

21.5

179

59

238

Other*2

9(13)

16.0-20.0
x = 18.2

166-195
x = 178.4

47-58
x = 52.1

219-252
x = 231.7

<J (9)

21.0-22.5
x = 21.7

160-179
x = 172.8

55-61
x = 59.1

220-240
x = 231.9

a Several authors record proportions and counts higher or lower than those reported here. Our
re-examination of some of these specimens indicates that certain reports are in error; either speci-
mens were incorrectly sexed or incorrectly measured or counted. Other reports (not included in
Table 1) have not been verified for this study, including: 8 subcaudals - 54 (Taylor and Smith
1939); 9 subcaudals - 46 (Taylor 1940); $ subcaudals - 59, $ V + Sc - 216, and 8 ventrals - 180,
8 subcaudals - 48,65, 8 V + Sc 219, 244 (Smith 1942); 9 subcaudals - 41 and 8 subcaudals - 43
and 51 (Davis and Dixon 1959); 9 subcaudals - 44 and 45 and 8 subcaudals - 53; 9 tail/total
length - 15.1, 8 tail/total length 18.1-20.5 (Davis and Smith 1953).

variable in several of them. The cephalic coloration and scalation are shown in figure 2.
We assign this snake to T. b. bocourti (see later discussion).

Although the Tres Marias specimen differs from other known mainland specimens
in the lower number of ventral and subcaudal scales, the majority of other characteris-
tics is typical of the species. As indicated above, most of the snakes on the Tres Marias
average more ventral scales than their mainland counterparts. The only other exception
to this rule is the other Tres Marias black-headed snake Tantilla calamarina that also
has fewer ventrals than mainland individuals of the same species. It would be inter-
esting to know whether this apparent reduction in ventral and/or subcaudal counts in
insular populations of Tantilla, but not of other Tres Marias snakes when compared
with their mainland counterparts, is an artifact of small sample size, is characteristic of
snakes of the genus Tantilla only, or is associated with the ecologies of the species
involved ( e.g ., semifossorial versus terrestrial or arboreal).

Sinaloa

The collection from the Sierra Surutato includes the following species: Amby-
stoma rosaceum (107 specimens), Bufo occidentalis (14), B. punctatus (1), Pachy-
medusa dacnicolor (1), Hyla arenicolor (18), Rana pipiens (11), R. tarahumarae
(6), Anolis nebulosus (6), Ctenosaura hemilopha (1), Holbrookia maculata (8),
Sceloporus clarkii (1),S. horridus (2), S. spinosus (2 ),S. virgatus (3), S. poinsettii (2),
S.jarrovii (41), S. nelsoni (11), Urosaurus bicarinatus ( 5),Eumeces callicephalus (4),
E. parviauriculatus (9), Cnemidophorus costatus (4), Gerrhonotus kingii (4), Masti-
cophis flagellum (1), M. striolatus (1), Salvadora bairdi (1), S. hexalepis (1), Storeria
storerioides (4), Thamnophis cyrtopsis (2), Tantilla bocourti (1), T. calamarina (1),

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Figure 2. Dorsal and lateral view of the head of a female Tantilla bocourti (LACM 25251)
from Isla Maria Cleofas, Tres Marias Islands.

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Notes on the Herpetofauna of Western Mexico

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T. wilcoxi (1). Several of these species represent important additions to the herpeto-
fauna of Sinaloa or are of interest for other reasons. They are discussed below together
with other species from the northern or southern part of the state.

Ambystoma rosaceum Taylor. — A large series of this salamander, including
eggs, hatchlings, larvae and neotenes, was taken at several localities in the Sierra
Surutato. This species appears to be restricted to small streams at higher elevations in
the pine-oak-madrone forest. Thirty-five small larvae (16-30 mm total length; JFC
uncataloged) were taken in two small tributaries of the Rio Sinaloa, 0.2 mi W Los
Hornos and 0.4 mi N Los Hornos (elevation 1890 m) on 19 and 22 February 1968; and
24 eggs and hatchlings (JFC uncataloged) from a stream in the Arroyo Ocurahui ( ca .
1920 m) were collected on 22 February 1969. The clustered eggs were attached to the
underside of a large rock that had fallen into the stream. Other specimens are 15 larvae
(83-1 17 mm; JFC 69-1 to 69-15) and one neotene (162 mm; JFC 69-16) taken in deep,
spring fed pools at the source of a stream in the Arroyo de Rancho El Madrono, 6. 1 mi
by road NE La Cienega {ca. 2135 m) on 24 February 1969; 20 larvae (21.5-70 mm;
JFC 71-1 to 71-18+2) and one neotene (142 mm; JFC 71-19) from Los Hornos {ca.
1890 m), 8 March 1971 ; and one larva (85 mm; JFC 71-20) from El Triguito {ca. 1 860
m), 10 March 1971.

These specimens are interesting from several standpoints. They are the first sala-
manders to be reported from Sinaloa; the nearest known localities for Ambystoma
rosaceum are about 100 kilometers to the east-northeast near El Vergel, Chihuahua,
and about 310 kilometers to the southeast near Las Adjuntas, Durango (Anderson
1961). They represent the first report of eggs and hatchlings for this salamander as well
as the first record of neoteny in the species, and they represent a population that breeds
in February rather than at the beginning of the wet season in June or July, as is char-
acteristic of other populations of A. rosaceum. Dr. James D. Anderson who currently
is studying this material will provide more detailed information on these specimens in a
later publication.

Bufo cognatus Say. — A single live specimen (UAZ 38720) was collected about
2200 hours by Mike Robinson on the road 9.2 mi SW San Bias on 6 June 1974. The
road was dry and no rain had fallen. This is the first record of Bufo cognatus in Sinaloa
and extends the range of this species about 1 10 kilometers southwest from previously
known localities between Huatabampo and Navojoa, Sonora (McDiarmid 1966).
McDiarmid (1966) predicted a southeastward extension of B. cognatus into Sinaloa
in association with the extensive agricultural development along the lower Rio Mayo
and Rio Fuerte drainages.

Rana tarahumarae Boulenger. — Two males (JFC 67-14 and 67-15) were col-
lected on 26 March 1967 in a creek in pine-oak-madrone forest at Los Homos (1890 m).
These specimens were mentioned by Zweifel (1968) as representing the first records of
this frog for Sinaloa as well as the southernmost locality for the species. They extend
the known range of Rana tarahumarae approximately 95 kilometers to the southwest
from Arroyo Tecolote de Los Loera, Chihuahua (Zweifel 1955). Four additional speci-
mens were taken on 19 and 24 February 1969. Two (JFC 69-61 and 69-62) were col-
lected in a riparian habitat below the pine-oak forest in Arroyo San Rafael at La Joya

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(1370 m) and the others (JFC 69-63 and 69-64) were taken around spring-fed pools in
a meadow surrounded by pine-oak-madrone forest at Arroyo de Rancho El Madrono
(2135 m). One of these specimens is a gravid female measuring 102.4 mm body length.
The latter two specimens were secured at an elevation about 300 m higher than pre-
viously recorded for this species (Zweifel 1968). Pertinent measurements and pro-
portions are presented in Table 2.

TABLE 2

Pertinent measurements and proportions for Surotato specimens assigned to Rana tarahumarae.

No.

Sex

Body

Length0

Tibia

Length

Head

Length

Head

Width

HL/HW

TL/BL

67-14

6

70.0

37.0

20.0

25.0

0.800

0.528

67-15

6

72.0

37.0

21.5

27.0

0.796

0.514

69-61

6

61.5

31.0

20.0

23.0

0.869

0.504

69-62

9

102.4

47.4

32.4

39.5

0.820

0.463

69-63

9

47.5

22.5

15.0

17.7

0.847

0.474

69-64

9

82.5

44.2

27.0

32.0

0.844

0.536

^ All measurements in mm; taken according to Zweifel (1955).

Welboum and Loomis (1970) reported a single specimen of Rana tarahumarae
from 8 km W Ameca, Jalisco as a host for a new species of chigger. This locality is
within the range of Rana pustulosa but considerably south of the southernmost rec-
ords for/?, tarahumarae. The proportions of R. tarahumarae , the Surotato specimens
and R. pustulosa are represented in Table 3. In both proportions the Surotato speci-
mens are intermediate between R. tarahumarae and R. pustulosa. They are more
similar to R. tarahumarae in HL/HW and more similar to R. pustulosa on TL/BL.
Dorsolateral folds are present but faint in the three males and either very faint or absent
in the females from Surotato. The tympanum is indistinct and covered by minute, white
tubercles. In other details the Surotato frogs are more similar to R. tarahumarae, two
of which were so referred by Zweifel (1968). However, the intermediate nature of the
Surotato specimens in certain characteristics previously used to distinguish the two
species, suggests that/?, pustulosa and/?, tarahumarae probably are conspecific. A
detailed study of this group of frogs in Western Mexico is needed.

TABLE 3

Proportions of samples of Rana tarahumarae, Surotato specimens and Rana pustulosa.

Samples

N

HL/HW

TL/BL

R. tarahumarae a

31

0.812±0.006(0. 755-0. 879)

0.486±0. 004(0. 41 8-0.522)

Surotato specimens

6

0.829±0. 012(0. 796-0. 869)

0.503 ±0.01 2(0. 463-0. 536)

R. pustulosaa

66

0.851 ±0.004(0.755-0.923)

0.508±0. 003(0. 436-0.563)

°Data from Zweifel (1955); figures represent mean, standard error of mean and range.

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Notes on the Herpetofauna of Western Mexico

9

Sceloporus spinosus Wiegmann. — Two immatures of this lizard were taken in
the Sierra Surotato: JFC 68-33, from beneath a log in pine-oak-madrone forest, 0.4 mi
by road N Los Hornos, ca. 1890 m, 22 February 1968; and JFC 69-67 , collected on a
fence post at Ocurahui, ca. 1920 m, 22 February 1969. These are the first specimens
from Sinaloa and the westernmost localities reported for the species (Smith 1939).
These also are the first records of this species from pine-oak-madrone forest habitat.
Cole (1970) indicated that the species is found primarily in subtropical savanna and
thorn scrub. They represent range extensions of approximately 355 km to the west-
northwest from the nearest previously published locality, Durango, Durango (Smith
1939) and about 225 km in the same direction from Santiago Papasquiaro, Durango
(JFC 66-78). Discovery of Sceloporus spinosus in the Surotato indicates that, con-
trary to the conclusion that Smith (1939:93) expressed, the elevated western margin of
the Mexican Plateau has failed to present an effective barrier to the northwestward
dispersal of this species. Pertinent data are 35.4, 44.1 mm snout-vent length; 28, 28
dorsal scales; 48, 46 ventral scales; 12-11, 12-12 femoral pores; 4-4, 4-4 supraoculars.
The number of dorsals closely resembles the mean for the geographically nearby nom-
inate subspecies as well as for the far-removed S. s. apicalis Smith and Smith of
Oaxaca; the ventral and femoral pore counts most closely approach the means for
S. s. caeruleopunctatus Smith of Guerrero and Oaxaca; and the number of supraoculars
best fits the mean for S. s. spinosus (Smith 1939; Smith and Smith 1951). Since the
data from our specimens is within the known range of variation for the nominate sub-
species, and also on geographic grounds, we provisionally allocate the Sinaloan speci-
mens to S. s. spinosus. A series of adults from this area will allow a more complete
understanding of the relationships of this population to others of the species.

Sceloporus virgatus Smith. — Three specimens of this species include a juve-
nile, 25 mm SV length (JFC 69-133) and two adult males, 45.6 and 47.3 mm SV (JFC
70-12; 70-13). They are typical representatives of the species in details of scalation and
general coloration (Cole 1968). These are the first records of Sceloporus virgatus for
Sinaloa and extend the known range of the species about 170 kilometers south-
southeast from between Cerocahui and Barranca de Urique, Chihuahua (Cole 1963).
The lizards were taken near rocky streams at El Triguito, ca. 1860 m, on 4 November

1969 (JFC 69-133) and at a site 2 mi by road SE Los Homos, 2075 m, on 4 October

1970 (JFC 70-12; 70-13).

Sceloporus poinsettii Baird and Girard. — Two specimens of this large sceloporine
lizard (JFC 69-135, adult male, 125 mm SV and 69-134, adult female, 99 mm SV)
were collected 1.1 mi by road SE La Cienega, ca. 1800 m, on 4 November 1969. The
male is the largest known specimen of this species, exceeding the previous record by 8
mm in snout-vent length (Taylor & Knobloch 1940; Stebbins 1966). Both were taken
during the day on a rocky road cut in pine-oak forest. These first records of Scel-
oporus poinsettii from Sinaloa help to fill the hiatus in the western range of the species
in Mexico. Previously, the specimens nearest to Sinaloa had been collected about 130
kilometers to the northeast near Guachochic, Chihuahua (Smith and Chrapliwy 1958)
and about 3 15 kilometers to the southeast near El Salto, Durango (Smith and Chrapliwy
1958). Smith and Chrapliwy diagnosed S. poinsettii macrolepis from southwestern
Chihuahua, southern Durango, and west-central Zacatecas as having fewer dorsal

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scales (85% with 26-29) than S. p. poinsettii (only 3% with less than 30). In this regard
the two Sinaloan lizards with 30 and 32 dorsal scales are more similar to the northern
subspecies of S. p. poinsettii than they are to populations from adjacent localities in
the intervening area. The nearest specimens of the nominate subspecies are from north-
ern and eastern Chihuahua, while those from the southwestern portion of the same state
were assigned to S. p. macrolepis. Additional specimens from west-central Chihua-
hua were considered “. . . intergrades between poinsetti and macrolepis, tending
strongly toward the latter race” (Smith and Chrapliwy 1958:268). In the same
paper these authors characterized S. p. polylepis from southeastern Chihuahua and
eastern Durango as possessing more dorsals (83% with 36-41) than S. p. poinsettii
(only 4% with more than 35). At the same time they pointed out that S', p. macrolepis
occurs at higher elevations than the nominate subspecies, while S. p. polylepis occupies
desert foothills at comparatively low elevations. We suggest that the single character
that serves to distinguish these three subspecies — the number of dorsal scales — may
be merely a function of environmental temperature and aridity. If additional collecting
in eastern Durango and eastern Sinaloa indicates the species to have a nearly continu-
ous range (which we suspect), then the geographic and elevational distribution of the
number of dorsal scales should be examined carefully.

Eumeces callicephalus Bocourt. — Four males of this species were taken on 19
and 20 February 1968 in the Sierra Surutato. Two (JFC 68-100; 68-101) are from
beneath rocks along a stream in a logged-over valley surrounded by pine-oak-madrone
forest 0.5 mi by road SE Los Hornos ( ca . 1920 m); the others (JFC 68-102; 68-103),
also beneath rocks, were found in the Canon de Tarahumare between La Joya and
Barranca de las Tahonitas (ca. 1310 m). The latter locality lies in an ecotone between
riparian forest and tropical deciduous forest, immediately below pine-oak forest. The
first specimen measures 58.5 mm in SV length and has the Y-shaped head-color pattern
typical of Eumeces callicephalus as depicted by Stebbins (1966). However, the other
three specimens (JFC 68-101; 68-102; 68-103) are very large males (72.0, 66.8, and
67.0 mm SV) and have either very faint head markings or lack them completely. The
largest specimen is approximately 8 mm longer in SV length than the maximum re-
ported for this species (Stebbins 1966). All specimens are representative of E. calli-
cephalus in most other characteristics. Other salient data for these four specimens are:
27 or 28 (3) scale rows, the median dorsals unwidened; 56, 58 or 59 (2) dorsal scales
(including nuchals); 7-7 supralabials; 6-6 infralabials; 2-2 loreals; 1-1 preoculars; 2-2
presuboculars; 2-2 postoculars; 4-4 postsuboculars; 1+2-1 +2 temporals; 4-4 supra-
oculars; 5-8, 7-8 (2) or 8-8 supraciliaries. The prefrontals are separated (by contact of
the frontal and frontonasal) in 68-100, fused (no seam) in 68-101, and touching (in
contact) medially in 68-102 and 68-103. A postnasal is present on both sides in 68-100,
absent on both sides in 68-101, and present on the left but absent from the right side
of 68-102 and 68-103. The parietals are in contact behind the interparietal in 68-100
and 68-102 and separated in the others. A pair of scales separates the single postmental
from the mental in 68-100; the other specimens have two postmentals. The scale bor-
dering the medial margin of each postgenial is longer than wide. A distinct dorsolat-
eral pale stripe is present on the smallest male but is faintly represented only on the
anterior part of the body of the three large males. There are four dorsal scale rows

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Notes on the Herpetofauna of Western Mexico

11

between the dorsolateral stripes anterior to the insertion of the forelimbs. A dark lat-
eral stripe is present on all animals, although it is faint in the large specimens. At mid-
body this dark lateral stripe involves from one and one-half to two and one-quarter scale
rows. The paler dorsal color between the lateral dark stripes at midbody covers six
full and two half scale rows, eight scale rows, or eight full and two quarter scale rows.
Adpressed limbs of the smaller male touch; they do not touch in the other three speci-
mens. Mr. Carl S. Lieb examined these specimens and confirmed our identifications.

Eumeces parviauriculatus Taylor. — Nine specimens of this small skink were
collected at the following localities: 1 mi by road SE Los Hornos, ca. 1980 m, 26 March

1967 (JFC 67-17; 67-18); 0.4 mi by road N Los Hornos, ca. 1890 m, 22 February

1968 (68-104); 2.7 mi by road SE Los Hornos, 2135 m, 23 February 1969 (69-82);
Arroyo El Pie la Cuesta, 1.8 mi by road NW Surutato, 1680 m, 23 February 1969
(69-85; 69-86); 1 mi by road E Buenas Juntas, 2075 m, 1 October 1970 (70-15; 70-16);
Rancho El Madrono, 2135 m, 10 March 1971 (71-21). Most specimens were taken
under rocks or in crevices in rocky cliffs in pine-oak forest. These are the first records
for the state, realizing the prediction by Legler and Webb (1960) that Eumeces parvi-
auriculatus would eventually be taken in northern Sinaloa. The specimens extend the
known range of this species about 200 kilometers southeast from previously reported
localities near Alamos, Sonora, and about 190 kilometers south-southeast from near
Temores, Chihuahua (Legler and Webb, 1960). Four females (SV 43.2, 52.0, 53.1,
54.0 mm) contain developing eggs. Two (67-17, 67-18) have three eggs measuring 5
mm and a fourth measuring 2 mm; the others have a total of 7 and 8 very small eggs.
The specimens range from 37 to 54 mm snout-vent length. In the two specimens with
complete tails (male, 70-15; female, 67-18), the tail lengths are 61 .4 and 64.9% of the
total length. Other important diagnostic data are: 4 supraoculars, no postnasals, 1 post-
mental, parietals not in contact behind interparietals, frontal in contact with fronto-
nasal, 20 scale rows, and 58 (damaged), 60, 62, 63 or 64 dorsal scales.

These specimens were compared with 5 specimens of E. parviauriculatus (MVZ
74187-90, 74198) from a streamside locality (elevation 2000 m) on the Sonora-
Chihuahua border above Alamos, Sonora. The Sinaloan specimens are similar in
most respects to this Sonoran material and to specimens reported in the literature (Tay-
lor, 1933; Taylor and Knobloch, 1940; Legler and Webb, 1960). This new material
increases the number of reported specimens of this small skink from five to nineteen.

Chilomeniscus cinctus Cope. — This first record of Chilomeniscus from Sinaloa is
based on a specimen (LACM 121310) collected on 22 September 1975, at Rancho Palo
Verde, 2.7 mi W Miguel Hidalgo Dam. Pertinent data are: juvenile female; 97 mm
total length; 12 mm tail length; 15-13-13 dorsal scale rows; 111 ventrals; 24 subcau-
dals; 7-7 supralabials; 8-8 infralabials; 1-1 preoculars; 2-2 postoculars; 1 + 1-1 + 1
temporals. A loreal scale is present on the right side but absent on the left. There are 20
dorsal black crossbands, 15 on the body, 4 on the tail, and 1 across the head. The dorsal
interspaces were reddish orange, with color restricted to the middle 5-7 scale rows. In
most respects this specimen is similar to one from southern Sonora reported by Bogert
and Oliver (1945). The occurrence of C. cinctus in Sinaloa is not unexpected as
specimens are known from Sonora at localities 55 km to the northwest at Alamos
(Bogert and Oliver, 1945) and 50 km to the west at a point 14.2 mi N Sinaloa-Sonora

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border on Mexico Highway 15 (UMMZ 134106, W. Van Devender, personal
communication).

Sonora aemula (Cope). — A third specimen of Sonora aemula from Sinaloa
extends the known range (Hardy and McDiarmid, 1969) of this species about 400
kilometers southward. Its occurrence in the southern limits of the tropical semiarid
forest is not surprising, as it is relatively common in this habitat in southern Sonora.
The southern distribution of this snake parallels those of Coleonyx variegatus and
Salvadora hexalepis. This specimen (LACM 51563) was found DOR by John K.
Cross on 12 September 1967, on Highway 15, 40 mi S Mazatlan. It is a female mea-
suring 280 mm in total length and 39 mm in tail length, with 149 ventrals, 34 sub-
caudals, 17-15-15 dorsal scale rows, 7-7 supralabials, 7-7 infralabials, 1 loreal (1 fused
with preocular), 1-1 preoculars, 2-2 postoculars, and 1 +2-1+2 temporals. The animal
has a pale snout, black head cap, black collar, reddish ground color, four dyads and
one triad on the body, two dyads on the tail, and the tail tip is black. Three of the body
dyads are black-yellow-black, one is yellow-black- yellow and the triad is black-
yellow-black-yellow-black. The highly variable color pattern is representative of the
species.

Tantilla bocourti (Gunther). — An adult female containing six enlarged ova
(three on each side) is the first specimen from Sinaloa and extends the known range of
the species (Fig. 1) about 345 kilometers northwest along the Pacific versant of the
Sierra Madre Occidental from near Pueblo Nuevo in southwestern Durango (Webb
and Baker 1962). The snake (JFC 68-1 1 1) was unearthed from rocky substratum dur-
ing road repairs in pine-oak forest 1.1 mi by road N La Joya, ca. 1525 m, on 21 Feb-
ruary 1968.

This specimen has more subcaudals and a longer tail than any other female exam-
ined (Table 1) but in other respects is representative of the species. Other pertinent
data are: 349 mm total length; 75 mm tail length; 7-7 supralabials; 6-6 infralabials;
1-1 preoculars; 2-2 postoculars; and mental in contact with chinshields. The primary
temporals are single and elongate (length is 3.5 times width); there is a small, scale-
like secondary temporal (length about equal to width) on the left. On the right side the
secondary temporal is lacking so that the parietal and seventh supralabial are in con-
tact. The tertiary temporals are single and scale-like on both sides. Two ova on each
side measure 6 mm in length while the anteromost on each side is smaller (3 mm). We
assign this specimen to Tantilla b. bocourti, since it agrees with the nominate sub-
species rather than T. b. deviatrix Barbour in all characters that have been used to dif-
ferentiate the two forms. The ventral count is well above the known maximum for
T. b. deviatrix, while the number of subcaudals falls below the minimum for the latter
subspecies. The scale-like secondary temporal is characteristic of T. b. bocourti as
opposed to the narrow, elongate condition in the other subspecies. Typical of the nomi-
nate subspecies is the widespread distribution of dark pigment on the head, which is
markedly reduced in extent in T. b. deviatrix. This morphological evidence is con-
sonant with the geographic picture, since T. b. deviatrix is known only from valley
habitats in the distant state of San Luis Potosi.

Tantilla calamarina Cope. — A single male (JFC 69-91) of this small secretive
snake was found in a rock crevice along a trail in mixed oak and tropical deciduous

1976

Notes on the Herpetofauna of Western Mexico

13

forest in the Canon Tarahumares at Vado Ceboletas, ca. 1 190 m, on 20 February 1969.
This record extends the known range of the species about 275 kilometers north from
near Mazatlan (Hardy and McDiarmid 1969). Pertinent data are: 147 mm total length;
29 mm tail length; tail 19.7% of total length; 136 ventrals; 44 subcaudals; 6-6 supra-
labials and infralabials; 1-1 preoculars and postoculars; and 1 + 1-1 + 1 temporals.
The prefrontals and parientals are separated from the labials. Both the ventral and sub-
caudal counts (and, consequently, the V + Sc count) are higher than those previously
reported for the species. In other respects, however, the scalation is typical of the spe-
cies as described by Smith (1942) and others ( e.g Peters 1954; Zweifel 1960).

This specimen is distinct in many aspects of coloration. The dorsal ground color
is pale brown; the venter is grayish white. The lateral edges of the ventrals and sub-
caudals, the labials, and the mental have faint scattered tan flecks. A brown stripe
extends middorsally from the head cap to the tail tip. Anteriorly it involves all of scale
row eight and the adjacent edges of scale rows seven and nine from the head cap back
to a position above ventral ten. From here the stripe is restricted to the central portion
of scale row eight, gradually fading as it approaches the tail. Distinct lateral stripes are
present. They consist of brown pigment spots on the upper third of the scales in row
three and the posterior quarter of scales in row four. This arrangement gives the lateral
stripes a zigzag appearance. In addition, there are dashes of brown pigment on the
posteromedial parts of scales in rows one, two, five, and six. These dashes give the
impression of discontinuous faint stripes, similar to the lateral stripes in a Tres Marias
specimen (Zweifel 1960). The head cap is connected to the middorsal stripe but is
separated from the lateral stripes by two crescent-shaped marks. These crescents arise
on each side behind the parietals and extend anteriorly across the upper third to half
of the secondary temporals, along the lateral edges of the parietals, through the upper
third of the postoculars, and across the supraoculars and lateral parts of the prefrontals
onto the intemasals. These marks are white on the upper half of the scales in row five,
the entire scale in row six, and most of the scale in row seven and clearly sets off the
dark head cap from the ground color on the body. Anterior to the parietals, the cres-
centic marks gradually darken to the pale brown ground color. The lateral stripes con-
tinue onto the head where they broaden to form a dark eye mask that separates the cres-
cents from the pale lower portions of the supralabials. The head cap is brown mottled
with paler flecks that increase in size on the prefrontal, internasal, and rostral scales.

Much of the described variation in head coloration of specimens of Tantilla cala-
marina (Taylor 1937; Peters 1954; Zweifel 1960) is the result of a break up of the
crescentic marks on the head. This specimen apparently has a much more discrete
color pattern than any previous specimens and lends additional support to the sugges-
tion that Tantilla martindelcampoi and T. calamarina are conspecific.

Tantilla wilcoxi Stejneger. — A single specimen of this relatively rare snake was
collected in a rock crevice in a road cut in pine-oak-madrone forest 4.8 mi by road SE
Los Hornos, 2075 m, on 19 February 1968. It is the first record for Sinaloa and extends
the known range about 250 kilometers south from Mojarachic, Chihuahua (Smith
1942) and about 360 kilometers to the west-northwest from near Chorro, Durango
(Webb and Hensley 1959). The specimen (JFC 68-112), an adult female, has the fol-
lowing characteristics: 295 mm total length; 70 mm tail length; tail 23.7% of total

14

Contributions in Science

No. 275

length; 157 ventrals; 63 subcaudals; 7-7 supralabials; 6-6 infralabials; 1-1 preoculars;
2-1 postoculars; 1 + 1-1 + 1 + 1 temporals; mental separated from chinshields. A
continuous white collar one and one-half scales wide on the midline includes the pos-
terior quarter of the parietals. The posterior dark border is irregular and only one-half
scale wide. Most of the fifth supralabial and an adjacent part of each anterior temporal
are white. Additional aspects of color pattern are essentially the same as described for
other specimens of Tantilla wilcoxi by Smith (1942), Webb and Hensley (1959), and
Stebbins (1966). In life, the dorsum was dark olive-green; the posterior two-thirds of
the venter and entire underside of the tail was orange-red. Inasmuch as both ventral and
subcaudal counts fall well within the reported ranges of variation for females of the
nominate subspecies and above the ranges for T. w. rubricata Smith, and since the
dorsal coloration is dark rather than reddish, we refer our specimen to T. w. wilcoxi.
This snake adds further confirmation to the prediction by McCoy (1964) that in Mexico
the nominate subspecies occupies the Sierra Madre Occidental to the west, while T. w.
rubricata occurs in the Chihuahua Desert to the east.

Crotalus stejnegeri Dunn. — Two specimens of this apparently rare rattlesnake
have been collected in Sinaloa since Hardy and McDiarmid (1969) reported a specimen
from near Santa Lucia. The first of these new specimens is a large male collected at
night by Carlton Hall as it crossed Highway 40, 10 mi NE Concordia in August 1967.
The specimen (LACM 37718) is 615 mm in total length. The tail is 91 mm long and
14.8% of the body length. In addition, this snake has the following pertinent charac-
teristics: 176 ventrals of which ventral 97 and 103 are half scales; 48 subcaudals of
which 41 are entire and the last seven divided; 27-23-29 dorsal scale rows; 15-15 supra-
labials; 16-15 infralabials; 2-2 preoculars; 4-4 postoculars; 3-3 suboculars; 32 dorsal
body blotches; and more than 10 tail blotches. The posterior tail blotches are difficult
to count due to darkening of the ground color. The matrix of the proximal rattle is black
at its base; the rattle is complete, with four segments and a terminal button. In addition
to being the largest specimen of the species reported in the literature, this snake has a
slightly longer tail, fewer body blotches, and fewer dorsal scale rows at midbody than
other known examples.

The second specimen (RS 901 HSH/RSS,NHSM) was collected on Highway 40
between 10 and 15 mi NE Concordia on 10 July 1972. The snake was found at a point
where the road crosses a dry creek bed. It was dusk, the air temperature being about
24°C, and the road temperature about 27°C. According to the collector, this locality is
about two miles west of the beginning of the pine forest, probably in subtropical dry
forest (Hardy and McDiarmid 1969). Herbert S. Harris provided collecting data and
the following information: juvenile female, 350 mm total length; 34 mm tail length;
tail 9.5% of body length; 172 ventrals; 36 subcaudals; 27-27-20 dorsal scale rows;
14-15 supralabials; 18-17 infralabials; 2-2 preoculars; 4-4 postoculars; 2-3 suboculars;
40 body blotches; 10 tail blotches; 1 segment plus button comprising rattle.

QUESTIONABLE RECORDS FOR SINALOA

We take this opportunity to correct a statement concerning the southern limit of
the range of Uta stansburiana. Tinkle (1969, Fig. 1) stated “The range of the south-
western race should extend slightly farther south into northern Sinaloa than shown

1976

Notes on the Herpetofauna of Western Mexico

15

(Royce Ballinger, personal communication).” In a recent letter concerning the accu-
racy of the map. Tinkle indicated that the comments in the caption were in error, and
neither he nor Royce Ballinger know of any records of Uta stansburiana from Sinaloa.

In 1969 Peters and Donoso-Barros reported the distribution of Mabuy a mabouya
alliacea as ‘‘Veracruz and Sinaloa, Mexico to Costa Rica.” Apparently their report of
Mabuya from Sinaloa is based on Burger’s (1952) incorrect transcription of the range
of the species. He listed specimens from Colima but cited the distribution as “Mexico
from the states of Veracruz on the Atlantic and Sinaloa on the Pacific coast. . . .”
We know of no verified records of Mabuya mabouya from Sinaloa. Some of the old
records for northern states in Mexico are vague and unsubstantiated and may well be
based on misidentifications. Hobart Smith (personal communication) knows of neither
specimens nor literature records for Mabuya in Sinaloa. We suggest that the report is
in error; on the west coast of Mexico, Mabuya is known from Colima south.

CONCLUSION

The report of Hypsiglena torquata and Tantilla bocourti from the Tres Marias
brings the insular herpetofauna of this island group to a total of 21 species, including
2 frogs, 1 turtle, 5 lizards, and 13 snakes. The new records of amphibians and reptiles
from Sinaloa, including the reports of Enulius oligostichus (McDiarmid and Bezy
1971) and Hyla bistincta (Duellman 1970) and the deletion of Uta stansburiana and
Mabuya mabouya, bring the native terrestrial herpetofauna of that state to 133 species,
including 1 salamander, 34 frogs, 5 turtles, 1 crocodilian, 35 lizards, and 57 snakes.

ACKNOWLEDGMENTS

John W. Wright, Natural History Museum of Los Angeles County (LACM),
made some of the material available for study. Hymen Marx, Field Museum of
Natural History, and Richard G. Zweifel, American Museum of Natural His-
tory, provided comparative material of Tantilla. David B. Wake, Museum of
Vertebrate Zoology (MVZ), loaned specimens of Eumeces. Herbert S. Harris and
Robert S. Simmons (HSH/RSS), Natural History Society of Maryland (NHSM),
Carl S. Lieb, University of Southern California, James D. Anderson, Rutgers Univer-
sity, R. Wayne VanDevender, University of Michigan, Museum of Zoology (UMMZ),
and Michael D. Robinson, University of Arizona (UAZ) provided data on certain
specimens. David J. McKirdy prepared the excellent illustration of Tantilla bocourti.
Saichi Kawahara, Steven R. Seavey, Robert F. Thome and Howard F. Towner
accompanied Breedlove in the field, each on different expeditions. To all of these
people go our sincere thanks.

RESUMEN

Desde Las Tres Marias nos viene por primera vez informe sobre dos especies
de serpientes, a saber: Hypsiglena torquata y Tantilla bocourti. Como resultado de
dicho informe y refiriendonos unicamenta al susodicho grupo de islas, llega el total de
la herpetofauna conocida a 21 a especies, o sean 2 ranas, 1 tortuga, 5 lagartijas y 13
serpientes. La salamandra Amby stoma rosaceum, las ranas Bufo cognatus y Rana

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No. 275

tarahumarae, las lagartijasEwracces parviauriculatus , Sceloporus poinsettii, S. spino-
sus y S. virgatus, y las serpientes Chilomeniscus cinctus, Tantilla bocourti y T. wilcoxi
se anaden a la fauna de Sinaloa. A cada especimen se le compara con otros miembros
de la misma especie, procedentes de diferentes puntos del area de distribucion geo-
grafica de la especie. Estos datos, juntos con los apuntes sobre seis otras especies,
anaden intensamente a nuestro conocimiento de la variedad, distribucion, y bio-
geografia de la herpetofauna de Mexico Occidental. Se suprimen de la fauna sinaloense
Uta stansburiana y Mabuya mabouya. Resulta pues que la herpetofauna terrestre y
oriunda de Sinaloa, se compone de 133 especies, a saber: 1 salamandra, 34 ranas, 5
tortugas, 1 cocodrilo, 35 lagartijas y 57 serpientes.

LITERATURE CITED

Anderson, J. D. 1961. The life history and systematics of Ambystoma rosaceum. Copeia,
1961:371-377.

Bogert, C. M. and J. A. Oliver. 1945. A preliminary analysis of the herpetofauna of Sonora.
Bull. Amer. Mus. Nat. Hist., 83:301-425.

Breedlove, D. E. and L. R. Heckard. 1970. Gentrya, a new genus of Scrophulariaceae from
Mexico. Brittonia, 22:20-24.

Breedlove, D. E. 1973. The phytogeography and vegetation of Chiapas (Mexico), Chapter 5,
in Vegetation and vegetational history of northern Latin America. Edited by Alan Graham.
Elsevier, Amsterdam. 393 pp.

Burger, W. L. 1952. Notes on the Latin American skink, Mabuya mabouya. Copeia, 1952:185-
187.

Cole. C. J. 1963. Variation, distribution, and taxonomic status of the lizard, Sceloporus undu-
latus virgatus Smith. Copeia, 1963:413-425.

1968. Sceloporus virgatus. Cat. Amer. Amphib. Rept., 72.1-72.2.

1970. Karyotypes and evolution of the spinosus group of lizards in the genus Scelo-
porus. Amer. Mus. Novitates, 2431:1-47.

Davis, W. B. and J. R. Dixon. 1959. Snakes of the Chilpancingo region, Mexico. Proc. Biol.
Soc. Wash., 72:79-92.

Davis, W. B. and H. M. Smith. 1953. Snakes of the Mexican state of Morelos. Herpetologica,
8:133-143.

Duellman, W. E. 1958. A preliminary analysis of the herpetofauna of Colima, Mexico. Occ.
Pap. Mus. Zool. Univ. Michigan, 589:1-22.

The amphibians and reptiles of Michoacan, Mexico. Univ. Kansas Publ. Mus. Nat.

Hist., 15:1-148.

1965. A biogeographic account of the herpetofauna of Michoacan, Mexico. Univ.

Kansas Publ. Mus. Nat. Hist., 15:627-709.

1970. The hylid frogs of Middle America. Monogr. Mus. Nat. Hist. Univ. Kansas,

1:1-753.

Gentry, H. S. 1946. Notes on the vegetation of Sierra Surotato in northern Sinaloa. Bull. Torrey
Bot. Club, 73:451-462.

Hardy, L. M. and C.J. Cole. 1968. Morphological variation in a population of the snake,
Tantilla gracilis Baird and Girard. Univ. Kansas Publ. Mus. Nat. Hist., 17:613-629.
Hardy, L. M. and R. W. McDiarmid. 1969. The amphibians and reptiles of Sinaloa, Mexico.

Univ. Kansas Publ. Mus. Nat. Hist., 18:39-252.

Legler, J. M. and R.G. Webb. 1960. Noteworthy records of skinks (genus Eumeces) from
northwestern Mexico. Southwestn. Nat., 5:16-20.

McCoy, C. J., Jr. 1964. Notes on snakes from northern Mexico. Southwestn. Nat., 9:46-48.

1976

Notes on the Herpetofauna of Western Mexico

17

McDiarmid, R. W. 1966. A study in biogeography: the herpetofauna of the Pacific Lowlands of
western Mexico. Masters Thesis, Univ. So. California. 296 pp.

1968. Variation, distribution and systematic status of the black-headed snak eTantilla

yaquia Smith. Bull. So. Calif. Acad. Sci., 67:159-177.

McDiarmid, R. W. and R. L. Bezy. 1971. The colubrid snake Enulius oligostichus in western
Mexico. Copeia, 1971:350-351.

Mertens, R. 1934. Die Insel-Reptilien, ihre Ausbreitung, Variation und Artbildung. Zool.
Stuttgart, 84:1-209.

Peters, J. A. 1954. The amphibians and reptiles of the coast and coastal sierra of Michoacan,
Mexico. Occ. Pap. Mus. Zool. Univ. Michigan, 554:1-37.

Peters, J. A. and R. Donoso-Barros. 1970. Catalogue of the Neotropical Squamata: Pt. II.

Lizards and amphisbaenians. U.S. Natl. Mus. Bull., 297:1-293.

Rzedowski, J. and R. McVaugh. 1966. La Vegetation de Nueva Gallica. Contr. Univ. Mich-
igan. Herb., 9:1-123.

Smith, H. M. 1939. The Mexican and Central American lizards of the genus Sceloporus. Zool.
Ser. Field Mus. Nat. Hist., 26:1-397.

Smith, H. M. 1942. A resume of Mexican snakes of the genus Tantilla. Zoologica, New York,
27:33-42.

Smith, H.M. and P. S. Chrapliwy. 1958. New and noteworthy Mexican herptiles from the
Lidicker collection. Herpetologica, 13: 267-271.

Smith, P. W. and H. M. Smith. 1951. A new lizard (Sceloporus) from Oaxaca, Mexico. Proc.
Biol. Soc. Washington, 64:101-103.

Stebbins, R. C. 1966. A field guide to western reptiles and amphibians. Boston, Houghlin Mifflin.
279 pp.

Taylor, E. H. 1933. New species of skinks from Mexico. Proc. Biol. Soc. Washington, 46:175-
182.

“1936” (1937). Notes and comments on certain American and Mexican snakes of the

genus Tantilla, with descriptions of new species. Trans. Kansas Acad. Sci., 39:335-348.

“1939” (1940). Some Mexican serpents. Univ. Kansas Sci. Bull., 25:445-487.

Taylor, E. H. and I. W. Knobloch. 1940. Report on an herpetological collection from the
Sierra Madre Mountains of Chihuahua. Proc. Biol. Soc. Washington, 53:125-130.
Taylor, E. H. andH. M. Smith. “1938” (1939). Miscellaneous notes on Mexican snakes. Univ.
Kansas Sci. Bull., 25:239-258.

Tinkle, D. W. 1969. Evolutionary implications of comparative population studies in the lizard
Uta stansburiana, pp. 133-154. In: Systematic Biology, Proc. Internat. Conf. Nat. Acad.
Sci., 1969, Washington D.C.

Webb, R. G. and R. H. Baker. 1962. Terrestrial vertebrates of the Pueblo Nuevo area of south-
western Durango, Mexico. Amer. Midi. Nat., 68:325-333.

Webb, R. G. and M. Hensley. 1959. Notes on reptiles from the Mexican state of Durango. Publ.

Mus. Michigan St. Univ., Biol. Ser., 1:249:258.

Welbourn, W.C., Jr. and R. B. Loomis. 1970. Three new species of Hannemania (Acarina,
Trombiculidae) from amphibians of western Mexico. Bull. So. Calif. Acad. Sci., 69:65-73.
Zweifel, R. G. 1955. Ecology, distribution, and systematics of frogs of the Rana boylei group.
Univ. California Publ. Zool., 54:207-292.

1959. Additions to the herpetofauna of Nayarit, Mexico. Amer. Mus. Novitates,

1953:1-13.

1960. Results of the Puritan-American Museum of Natural History expedition to

western Mexico. 9. Herpetology of the Tres Marias Islands. Bull. Amer. Mus. Nat. Hist.,
119:77-128.

1968. Rana tarahumarae. Cat. Amer. Amphib. Rept., 66.1-66.2.

Accepted for publication June 30, 1975.

501H3

c 2 L set

NUMBER 276
JUNE 23, 1976

THE DISTRIBUTION OF RODENTS
IN OWENS LAKE REGION
INYO COUNTY, CALIFORNIA

By John O. Matson

NATURAL HISTORY MUSEUM OF LOS ANGELES COUNTY

m

at

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CONTRIBUTIONS IN SCIENCE contain articles in the earth and life sciences, presenting
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Printed in the United States of America by Chapman’s Phototypesetting on 70# Patina Book

THE DISTRIBUTION OF RODENTS IN OWENS LAKE REGION,
INYO COUNTY, CALIFORNIA1

By John O. Matson2

Abstract: The distribution and relative abundance of rodents in Owens Lake
Region, Inyo County, California are discussed. Seventeen species (18 subspecies)
of rodents were recorded from 10 plant associations. Factors limiting the distribu-
tion of some rodents were soil texture (Dipodomys deserti, Perognathus formosus
and Peromyscus crinitus) and vegetation (Reithrodontomys megalotis, Microtus
calif ornicus and Mus muse ulus). The relative abundance of the other species may
be influenced by either or both factors. The number of rodent species in each plant
association was positively correlated with increased vegetative spatial heterogeneity.
Faunal relationship values are compared for each plant association. Biogeographical
comments are given.

INTRODUCTION

The Owens Valley of California is an area where vegetational elements com-
mon to northern and southern deserts come into contact. A shadscale vegetation
zone, lying between the northern sagebrush zone and the southern creosote bush
zone, occupies all but the most southern portion of Owens Valley (Billings 1949).
Because of this Billings (1949) regarded the vegetation in Owens Valley as an
ecotone between the northern and southern deserts.

Rodents are one of the most ecologically important factors in a community
(Fautin 1946). Therefore, a study of rodent distributional patterns and abundance
is an important aspect of community ecology. Information concerning mammalian
distribution and abundance in the Owens Valley is scarce. Annotated checklists of
the mammals from this area were given by Elliot (1904) and Grinnell (1933); how-
ever, their lists were incomplete giving only generalized information on distribu-
tional patterns. Most literature dealing with the mammals from this area basically
is taxonomic, describing new forms or discussing the status of these forms (Merriam
1894 and 1897; Bailey 1898 and 1915; Elliot 1903; Hollister 1913 and 1914; Grin-
nell 1922; Hall and Dale 1939; and Lidicker 1960). More recently, various ecological
studies (Kenagy 1972, 1973a, 1973b; Brown 1973; Brown and Lieberman 1973)
have added to our knowledge of the rodent fauna of Owens Valley.

The purpose of this investigation was to study the distribution and relative
abundance of rodents in the Owens Lake Region of Inyo County, California. The
Owens Lake region was selected because of the ecotonal nature of vegetation and
because the rodent distribution patterns had not been adequately studied.

Review Committee for this Contribution
George F. Fisler
David Huckaby
Donald R. Patten

2Mammalogy Section, Natural History Museum of Los Angeles County; current address,
The Museum, Michigan State University, East Lansing, Michigan 48824

2

Contributions in Science

No. 276

GENERAL DESCRIPTION OF THE STUDY AREA

The Owens Valley is located in west central Inyo County, California, with
Owens Lake at the southern end of the valley. Owens Lake is bounded on the east
by the Inyo Mountains and to the west by the Sierra Nevada Mountains. The majority
of the study area is in the Upper Sonoran Life Zone (Merriam 1898), which is
characterized by the presence of several species of Atriplex and Sarcobatus. An
extension of the Lower Sonoran Life Zone is evident in the southern portion of the
study area, characterized by the presence of Creosote bush (Larrea divaricata).
All of the study area is in the Mohavian Biotic Province of Dice (1943). In part, it
is the Western Desert Scrub Formation of Clements (1920) with the major portion
being the Basin Sagebrush Formation.

The entire Owens Valley is an alkali sink, becoming progressively more alka-
line southward to Owens Lake (Gale 1915). With the completion of the Lo$ Angeles
Aqueduct, in 1913, Owens River water was diverted from the lake (Schumacher
1962). Today the lake is dry, except for a few salt marshes found along the former
shoreline.

In the study area, the elevation extended from 3600 feet to 4249 feet; how-
ever, all field stations were located between 3600 feet and 3840 feet.

Climatic data were not available for the Owens Lake region itself since the
nearest weather stations are at Independence, 15 miles to the north, and Haiwee,
5 miles to the south. Sprague (1941) recorded average January temperatures from
these two weather stations as 39.0°F and 39.5°F, respectively. Average July tem-
peratures were 78.3°F for Independence and 81.9°F for Haiwee. Average annual
precipitation for a 40-year period at Independence was 4.49 inches, while at Haiwee
it was 4.87 inches over a 16-year period (Sprague 1941). The differences were small
between these two weather stations. Since Owens Lake is found between these sta-
tions, it may be assumed that the macroclimate is similar throughout the study area.

METHODS OF STUDY

Field stations were initially selected on the basis of apparent differences in
habitat. Differences in plant species, number of plants per unit area, degree of rocki-
ness, visibly different soil textures, and slope exposure were used as indicators of
habitat distinctness.

A total of eleven field stations were studied (Fig. 1). Of these, ten were inten-
sively studied during July and August 1971. The eleventh field station (Stream
Side Association) was studied in October 1968.

Plants

A plant quadrat, 66 ft by 66 ft (20.1 m by 20.1 m), was staked out on each
field station using a steel tape and compass. The perennial plants in each quadrat
were identified and counted, except at stations 4 and 1 1 where most of the plants
were too numerous to count. Notes were made of any other plants found at a field
station but not occurring in the plant quadrat. Only the most prominent plants found

1976

The Distribution of Rodents in Owens Lake Region

3

Figure
See text

1. Map of study area showing trapping localities and distribution of plant association,
for explanation of abbreviations.

4

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No. 276

in the plant quadrat were used in naming an association. The maximum height and
width of each perennial plant was measured. The per cent cover area (Table 1) and
volume (see Pianka 1966) were determined from these measurements.

Identification of plants was determined in the field using Munz and Keck
(1959) and Jaegar (1941). Plant nomenclature follows that of Munz and Keck (1959).
Numbers of plants per acre, by species, for each field station is given in Table 1 .

Soils

A soil sample was collected from each plant quadrat. A core sample was taken
from the top six inches of soil and placed in an air-tight one-quart jar for subse-
quent analysis.

Texture analysis and the classes of soil texture follow those used by Hardy
(1945). In order of decreasing particle size these are: granule gravel [passes through
one-half inch (1.27 cm) mesh but not one-eighth inch (.32 cm)]; coarse sand [passes
through one-eighth inch (.32 cm) mesh but not #20 mesh]; fine sand (passes through
#20 mesh but not #80); and silt and clay (passes through the #80 mesh).

Field stations with rocks one-half inch or larger in diameter were assigned
class numbers according to the degree of rockiness. Class #1 was relatively free
of rocks. Class #2 contained rocks one-half inch to three inches (7.62 cm) in diam-
eter. Class #3 had numerous rocks over three inches but less than twelve inches
(30.48 cm) in diameter. Class #4 contained rocks over twelve inches in diameter.
The results of the soil texture analysis are given in Table 2.

Results of soil analyses for levels of pH and soluble chlorides, sulfates and
borates, by using a La Motte Soil Kit, are indicated in Table 3. Soil chemical anal-
yses showed no direct correlation with rodent distribution or abundance, although
Hardy (1945) did demonstrate indirect effect of soil chemicals as they affected
plant distribution.

Rodents

Trapping to determine the presence and relative abundance of rodents was
carried on at irregular intervals from October 1968 through May 1969. An inten-
sive trapping period using a quadrat-removal method (Bole 1939; Cahalane 1941)
was conducted during July and August 1971.

The trapping carried on during 1968 and 1969 was accomplished using single
traplines. Each line was set in a definite plant association but in different localities
than the field stations. A trapline consisted of 20 to 35 trap stations set approxi-
mately 25 feet (7.62 m) apart with three traps per station. The total trapping results
(combining both line and quadrate data) is given in Table 4.

A trapping quadrat was staked out at each field station using a steel tape and
compass (Manville 1949). The quadrat consisted of three traplines set 50 feet
(15.24 m) apart. Each line was composed of 20 trap stations placed 25 feet (7.62 m)
apart with three traps per station (two museum specials and one Sherman live trap).
A total of 180 traps per quadrat was used. This quadrat enclosed an area of 475 feet
by 100 feet (144.78 m by 30.48 m) or about 1.1 acres (.445 ha).

TABLE 1

LIST OF ESTIMATED NUMBERS OF PLANTS PER ACRE3

Field Station4

1976

The Distribution of Rodents in Owens Lake Region

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TABLE 4

RELATIVE ABUNDANCE OF RODENTS PER 100 TRAP-NIGHTS (ALL DATA)!

1976

The Distribution of Rodents in Owens Lake Region

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TABLE 5

1976

The Distribution of Rodents in Owens Lake Region

9

Trapping was carried on for three consecutive nights at each field station (Bole
1939; Dice 1938). The traps, baited with rolled oats, were set in the afternoon of
the first night. Traps were emptied and rebaited the following two mornings and
afternoons. Thus, a total of 540 trap-nights was recorded for each field station,
except for Station 1 1 where only 456 trap-nights were used. The results of quadrat
trapping are shown in Table 5. Gopher traps were used to capture pocket gophers
when burrows were observed.

Trapping results are recorded as the number of rodents per 100 trap-nights;
these were assumed to reflect the relative abundance of rodents. Estimates of rodent
populations are not attempted, but rather, a comparison of the relative abundance
of each species was determined within an association and between associations.

The classification of rodents follows that of Hall and Kelson (1959). Original
description and/or the latest revision of the taxa were consulted for all identifications.
Specimens collected during this study were deposited in either the collections at
California State University, Long Beach, or the Natural History Museum of Los
Angeles County.

DESCRIPTIONS OF VEGETATION

Two distinct vegetation types composed of ten plant associations occur in the
study area. The abbreviation, in parentheses, following an association name is the
designation to be used throughout the text for that association.

Desert Shrub Vegetation

The Desert Shrub Vegetation includes eight plant associations in this study
area. It is characterized by plants that are widely spaced and adapted to xeric condi-
tions. This community represents the major portion of the study area.

Atriplex confertifolia Association (AC). — This association covered almost
all of the lower portion of what Knopf (1918) referred to as the alluvial piedmont
slope of the eastern Sierra Nevada Mountains in the region of Owens Lake. On
higher parts of the alluvium the rocky slopes became more prominent. Lower on the
alluvium this association merged with the marshes along the lake shore. The area
was dissected by the numerous washes of Carroll, Cottonwood and Ash Creeks.
This association is irregularly distributed throughout the Owens Valley (Billings
1949). In general the slope gradient was about 2.5 per cent northeast. Field Station
I was located in this association (Fig. 2).

Twelve species of rodents were recorded from this association (Table 4). The
most abundant was Dipodomys merriami, followed by Perognathus longimembris .

Franseria dumosa Association (FD). — This association included the area
above and west of AC. It merged to the south with the Larrea Association. The
slope gradient at the field station was 10.8 per cent northeast. Field Station 2 was
located in this association (Fig. 3).

Ten species of rodents occurred in this association (Table 4). The most abun-
dant was Perognathus longimembris (Tables 4 and 5).

10

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Figure 2. Field Station 1, Atriplex confertifolia Association.

Larrea Association (LD). — This association covered the southwestern portion
of the study area, from about one mile south of Ash Creek to well south of Olancha.
In the present study area it occurred only on the lower, more rocky slopes of the
Sierra Nevada Mountains. It also occurred on the higher slopes of the Coso Moun-
tains south of Owens Lake (outside the present study area). The slope gradient at

Figure 3. Field Station 2, Franseria dumosa Association.

1976

The Distribution of Rodents in Owens Lake Region

11

the field station was 7.7 per cent southeast; in other areas it was nearly level. Field
Station 3 was located in this association (Fig. 4).

Figure 4. Field Station 3, Larrea Association.

In this association ten species of rodents were recorded (Table 4). The most
abundant species were Perognathus formosus and Peromyscus crinitus, both occur-
ing in about equal numbers. Perognathus longimembris was only slightly less abun-
dant (Tables 4 and 5). Rodents were more numerous in this association during the
summer of 1971 than in any other association.

Atriplex Scrub Association (A). — This association included most of the south-
ern portion of the study area except the lake shore and the sand dunes areas. It merged
with the creosote bush on the higher slopes of the Coso Mountains to the south. To
the west it was bounded by the sand dunes. Its eastern limit was not determined,
but was assumed to be on the lower slopes of the Inyo Mountains. The slope gra-
dient at Field Station 6 is 5.6 per cent northwest, while Field Station 7 is somewhat
steeper, 12 per cent northwest. Field Stations 6 and 7 are located in this association
(Fig. 5).

Only five species of rodents were recorded from this association (Table 4),
Dipodomys merriami being the most abundant. Station 6 seemed to be more pro-
ductive in its rodent populations than did Station 7 (Table 5). This was probably
because of the steeper slope and less dense plant cover at Station 7.

Suaeda-Atriplex Association (SA). — This association included a small area in
the eastern portion of the study area, from about 2.5 miles south of Keeler to the
Atriplex Scrub Association. It is part of the flood plain of the Malpais Mesa of the
southern Inyo Mountains. The slope gradient was about 4 per cent west. Field Sta-
tion 9 was located in this association (Fig. 6).

12

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Figure 5. Field Station 6, Atriplex Scrub Association.

Figure 6. Field Station 9, Suaeda- Atriplex Association.

Only three species of rodents were recorded from this association (Table 4),
Perognathus formosus being the most abundant.

Atriplex-F ranseria Association (AF). — This association was irregularly dis-
tributed along the northeastern shore of Owens Lake. It merged in the north with
the sand dunes and to the south with the Suaeda-Atriplex Association. For the most
part, this association was found above the sand dunes on the western alluvium of

1976

The Distribution of Rodents in Owens Lake Region

13

Figure 7. Field Station 8, Atriplex-Franseria Association.

the Inyo Mountains. In general, the slope gradient was southwest 5 per cent. Field
Station 8 was located in this association (Fig. 7).

Six species of rodents occurred in this association (Table 4). The most abun-
dant rodent was Dipodomys deserti.

Sarcobatus-Atriplex parryi Association (SAP). — This association occurred in
the southern portion of the study area, from just east of Olancha to about the region
of Keeler. It was a narrow strip, lying between the lake shore and the Atriplex Scrub
Association. Its distribution was not continuous; instead, it occurred as isolated
stands surrounded by other habitats. This association occurred on sand dunes and
reached its optimum development about two miles east of Olancha, where the dunes
may attain heights of over 50 feet above the surrounding terrain. The dunes in this
area are apparently still in the process of active migration. Field Station 5 was located
in this association (Fig. 8).

Six species of rodents occurred in this association (Table 4). The most abun-
dant species was Dipodomys merriami followed by D. deserti.

Sarcobatus-Atriplex confertifolia Association (SAC). — This association oc-
curred on the sand dunes at the northern end of Owens Lake. It was somewhat
irregularly distributed along the eastern lake shore, eventually merging with the
southern dunes near Keeler. These dunes are reportedly the old beach dunes of Owens
Lake (Knopf 1918). They were smaller than those found at the southern end of the
lake. Also, they do not appear to be actively migrating. Field Station 10 was located
in this association (Fig. 9).

Seven species of rodents occurred in this association (Table 4). The same species
occurred here as in the southern dunes with the addition of Onychomys torridus.
Again, Dipodomys merriami was the most abundant.

14

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No. 276

Figure 8. Field Station 5, Sarcobatus-Atriplex parry! Association.

Figure 0 Field Station 10, Sacrobatus-Atriplex confertifolia Association.

Riparian Vegetation

The Riparian Vegetation is separated into two associations. This vegetation
type is characterized by plants which need abundant ground water. The main dif-
ference between the two associations was the number of trees present. The Stream
Side Association contained relatively more cottonwoods and willows than did the
Lake Shore Marsh.

1976

The Distribution of Rodents in Owens Lake Region

15

Stream Side Association (SS).— This association reaches its optimum along
the Owens River at the north end of the lake. There was also a more restricted Stream
Side Association along Cottonwood Creek. Field Station 11 was located in this
association (Fig. 10).

Figure 10. Field Station 11, Stream Side Association.

Nine species of the rodents were recorded from this association (Table 5). The
most abundant was Peromyscus maniculatus.

Lake Shore Marsh Association ( LSM ). — This association was irregularly dis-
tributed around the lake. Field Station 4 was located in this association (Fig. 11).

Figure 1 1 . Field Station 4, Lake Shore Marsh Association.

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No. 276

Eight species of rodents were recorded from this association (Table 4). One
species, Thomomys bottae, was represented by two subspecies, T. b. operarius on
the eastern shore, and T. b. perpes on the western shore of the lake. The most abun-
dant species was Peromyscus maniculatus followed by Reithrodontomys megalotis.

ACCOUNTS OF SPECIES OF RODENTS

During the course of this study, a total of 8141 trap-nights produced 406 rodents
(pocket gophers not included because of the different trapping procedures utilized).
Of the 18 forms expected, I either collected or observed 17 forms. Microtus cali-
fornicus vallicola was the only rodent not trapped or directly observed during this
study.

Ammospermophilus leucurus leucurus (Merriam). — The antelope ground
squirrel was the fourth most abundant rodent taken during this study, comprising
7.6 per cent of the total rodents captured. It was common throughout the study area
and absent from only one association (SA Association).

Overall, the antelope ground squirrel was most abundant in the SAC Associa-
tion (Table 4). During the summer of 1971, it was most abundant in the LD (Table 5),
where large rocks and plants provided sufficient shelter against the summer heat.
Summer activity of A. 1. leucurus may be restricted to those areas supplying suffi-
cient protection against extreme temperatures (Dawson 1955).

Spermophilus beecheyi parvulus (Howell). — The California ground squirrel
was not taken during this study; however, visual observations were common. They
were recorded from the western side of Owens Valley (Grinnell and Dixon 1919).
I observed these squirrels only on the west side of Owens Valley and only in very
rocky areas. They were never observed on the lower slopes of the alluvium, where
large rocks are absent.

Seasons of peak activity in the study area seemed to be spring and early fall
when ambient temperatures were moderate. California ground squirrels were
observed in the LD and FD Associations during May 1969. They were also observed
in the FD Association in early November 1968. They were not observed in February
1969, nor during the summer of 1971.

Thomomys bottae operarius Merriam. — The burrows of this subspecies of
pocket gopher were quite numerous near the town of Keeler, during the summer of
1971. Surface activity of pocket gophers can be estimated from the number of bur-
rows observed in an area (Crouch 1933). Surface activity also seems to be dependent
on soil moisture (Crouch 1933; Miller 1948; Laylock 1957). The soil at Keeler was
observably moister than in other areas, which probably accounted for the apparent
high abundance of burrows observed.

Thomomys b. operarius was known only from the type locality — the town of
Keeler on the eastern shore of Owens Lake (Merriam 1897; and Bailey 1915). Dur-
ing this study, specimens of T. b. operarius were taken at Keeler and at a locality
three miles south of Keeler in sandy soils where salt grass (Distichlis spicata) was
predominant. This was the same type of habitat that Grinnell (1933) recorded as
preferred by this race of pocket gopher.

1976

The Distribution of Rodents in Owens Lake Region

17

Thomomys bottae perpes Merriam. — This pocket gopher was found along the
western side of Owens Valley (Bailey 1915; Grinnell 1933). The soils in this area
were dry during the summer of 1971, which probably accounted for the noticeable
lack of fresh burrows. Fresh burrows were observed during January, February and
May, when winter rains had moistened the soils.

Pocket gophers in southwestern Utah may be restricted to areas with soils
containing less than three per cent granule gravel (Hardy 1945). In the present study,
burrows of Thomomys b. perpes were observed in the FD and AC Associations. Both
of these associations have soils with over 20 per cent granule gravel.

Perognathus longimembris longimembris (Coues). — The little pocket mouse
was the third most abundant rodent in the study area, 13.6 per cent of the total
rodents. It was not taken during the colder months of the year, the earliest record
being in late May 1969. Its latest record of occurrence was in late August 1971. It
seemed unlikely that this pocket mouse could be inactive for more than a week at a
time (Bartholomew and Cade 1957). Its absence from winter trapping records in
the present study may have been the result of the irregularity of winter trapping
periods. Specimens of Perognathus l. longimembris have been taken in all seasons
of the year in other areas (Dean Harvey, personal communication). Specimens at
the Los Angeles Museum have recorded dates of capture as late as November 23
(Cabazon, Riverside Co., California) and as early as April 3 (Mohave, Kern Co.,
California). Kenagy (1973b) found P. 1. longimembris to be less active above ground
in winter, but quite active within its burrows.

Perognathus /. longimembris occurred in greatest numbers in the AC Associa-
tion (Tables 4 and 5). This was also recorded forP. /. longimembris in western Utah
(Fautin 1946). P. 1. longimembris in southwestern Utah was reported to prefer non-
gravelly soils, soils with less than 10 per cent granule gravel (Hardy 1945). This
was not found to be the case with P. 1. longimembris of the Owens Lake region,
where they occurred in greatest abundance on the gravelly soils (22.6 per cent gran-
ule gravel) of the AC Association.

Perognathus l. longimembris occurred in eight of the eleven field stations
(Table 5), being absent from Stations 4 and 11 (Riparian Community) and Station 7
(A Association). It was present at Station 6 of the A Association. Steep slopes may
be a limiting factor in the distribution of this species (Hardy 1945). Its absence
from Station 7 (slope gradient of 12 per cent) and presence at Station 6 (slope gra-
dient of 5.6 per cent) may be because of the steeper slope at Station 7.

Perognathus formosus mohavensis Huey. — The long-tailed pocket mouse
was taken in only three associations (Table 4), all of which were in rocky habitats.
This is in accord with what other authors have recorded as the preferred habitat for
this species (Hardy 1945; Fautin 1946; Hall 1946).

Perognathus f. mohavensis was taken along with P. 1. longimembris in the
three associations. In two of the associations (L and SA), P. f. mohavensis was
the more abundant of the two. This may be because more rocks were present at these
two associations. In the FD Association, P. 1. longimembris was more abundant
than P. /. mohavensis; because there are relatively few rocks at this association, it
is probably a marginal zone for the occurrence of P. f. mohavensis.

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Trapping records were not complete enough for any generalizations concerning
seasonal activity of this pocket mouse. They were absent from the LD Associa-
tion in late May 1969 (212 trap-nights), this association producing the largest num-
bers of P. f. mohavensis during the summer of 1971 . P. f. mohavensis was recorded
as being equally active during all seasons in the Providence Mountains of California
(Johnson, Bryant and Miller 1948).

Dipodomys microps microps (Merriam). — The chisel-toothed kangaroo rat
was taken in all associations studied in western Utah by Fautin (1946) but seemed
to prefer the shadscale and tetradymia associations. In southwestern Utah, it pre-
ferred gravelly or sandy soils and tended to shun rocky soils (Hardy 1945). In the
present study, Dipodomys m. microps was most abundant on the gravelly soils of
the AC Association (Tables 4 and 5), but was also taken in lesser numbers in the
rocky LD Association and the sandy SAC Association. It is likely that the AC Asso-
ciation, with its gravelly soils, presents the optimum conditions for its existence.
Recently, Kenagy (1972 and 1973a) had demonstrated the importance of saltbush
(Atriplex confertifolia ) in the diet ofD. m. microps in Owens Valley.

Dipodomys panamintinus mohavensis (Grinnell). — The Panamint kangaroo rat
was not abundant in the two associations where it occurred (Tables 4 and 5). It has
been reported to prefer gravelly soils (Grinnell 1933; Johnson et. al. 1948). During
the present study, it was taken on gravelly soils and in rocky areas, but it was absent
from sandy soils. It was taken once from the edge of a LSM Association north
of Olancha, probably as the result of wandering from a more typical habitat above
the marsh.

Dipodomys p. mohavensis was reported to be absent from the east side of
Owens Valley (Elliot 1904). This was also noted during the present study. It has
been recorded from apparently sandy soils at the southern end of Owens Lake in
association with D. merriami and D. deserti (Grinnell 1922). It may occur only
marginally on sandy soils, where they merge with gravelly soils, as in the area at
the southern end of the lake. If D. p. mohavensis does indeed tend to shun sandy
soils, then its absence from the east side of Owens Valley can be explained, because
soils in that area are predominantly sandy.

Dipodomys merriami merriami (Mearns). — Merriam ’s kangaroo rat was pres-
ent in all plant associations studied (Table 4). It was most abundant in the SAC and
AC Associations. Overall, it was the most abundant rodent in the study area, 30.5
per cent of the rodents being of this species. D. m. merriami was found to be the
most widely distributed and abundant rodent in southwestern Utah (Hardy 1945).
In southern Arizona, the distribution of D. m. merriami coincided with the distri-
bution of creosote bush (Reynolds 1958), although it was present in other situations
as well.

During the summer of 1971, D. m. merriami was about equally abundant in
eight of the field stations, while being considerably more numerous at Station 10
(Table 5). It was absent from Stations 4 and 8 during the summer, but it was present
in these associations during other trapping periods.

During the colder months of the year, D. m. merriami was one of the two most
abundant rodents; Peromyscus maniculatus was the other. During the summer,

1976

The Distribution of Rodents in Owens Lake Region

19

however, its abundance was at a minimum, as was that of P. maniculatus. Possibly
this was the result of the greater activity of the two species of Perognathus. In south-
ern Arizona, D. m. merriami reached its highest densities in July (Reynolds 1958).

Dipodomys deserti deserti Stephens. — The desert kangaroo rat was reported
to occur only where deposits of wind-blown sand are deep and easily workable
(Grinnell 1914; Huey 1951; Durrant 1952). This was also apparent in the present
study.

Dipodymus d. deserti was most abundant at Station 8, the AF Association
(Tables 4 and 5) that had sandy soils. Overall, D. d. deserti was about twice as
numerous in the AF Association as in the two associations found on the sand dunes;
within the AF Association, it was about ten times more abundant than the other
two rodents during the summer (Table 5).

Reithrodontomys megalotis megalotis (Baird). — In the Owens Lake region,
Reithrodontomys m. megalotis was most abundant in the Riparian Vegetation (Table
4). It was taken only once in the Desert Shrub Vegetation (AC Association) where
the trap-line was set about 100 yards from the SS Association at Cottonwood Creek.
The SS Association had about one-half again as many harvest mice as the LSM
Association (Tables 4 and 5).

The western harvest mouse is not confined to any one type of habitat, but did
seem to prefer grassy areas near water (Long 1940; Hall 1946; Hooper 1952). It
could be that the distribution of this mouse depends upon the presence of heavy
vegetation (Hardy 1945).

Peromyscus maniculatus sonoriensis (Le Conte). — The deer mouse was the
second most abundant rodent, 14.3 per cent of the rodents being of this species. It
was absent from only three associations (Table 4); upon further study, it will prob-
ably be found to occur in them as well. It was most abundant in the Riparian Vegeta-
tion and in the SAC Association of the Desert Shrub Vegetation.

Its absence from the AC Association in the summer of 1971 coincided with
the high abundance of Perognathus longimembris (Table 5). Whether this was the
result of competition between the two species cannot be determined from present
data.

Deer mice are usually one of the most abundant mammals in areas where they
occur (Hall 1946; Manville 1949). However, in desert situations, it is usually out-
numbered by heteromyid rodents (Baker 1968). Most species of Peromyscus usually
have well defined habitat preferences, P. m. sonoriensis being the least restricted
of all (Grinnell and Orr 1934; Baker 1968).

Peromyscus crinitus stephensi Mearns. — The canyon mouse was taken in
only two associations, both of which were in rocky habitats (Table 5). It was most
abundant in the LD Association, occurring in numbers equal to that of Perognathus
formosus (Table 5), which was also restricted to rocky habitats. The canyon mouse
is reportedly restricted to rocky habitats (Hardy 1945; Fautin 1946; Hall 1946).

Peromyscus boylii rowleyi (Allen). — Only four specimens of Peromyscus b.
rowleyi were taken, two in the FD Association and two in the AC Association. The
occurrence of this mouse on the desert floor was unexpected. However, they were
quite numerous in nearby Cottonwood Canyon (Matson 1974). The two associations

20

Contributions in Science

No. 276

where P. b. rowleyi occurred were on the flood plain of Cottonwood Creek. It is
possible that these mice moved down the canyon to the desert floor in response to
population pressures. The brush mouse was reported to prefer areas of heavy vege-
tation (Bailey 1932; Grinnell 1933; Jameson 1951).

Onychomys torridus clarus Hollister. — During the present study, six speci-
mens of Onychomys t. clarus were taken, five in the Desert Shrub Vegetation and
one in the Riparian Vegetation (Table 4). They were found to occur on rocky, grav-
elly and sandy soils. There were no apparent differences in the amount of cover nec-
essary, for they were taken at Station 6, with sparse vegetation, and at Station 11,
with heavy vegetation. The southern grasshopper mouse in southwestern Utah
seemed to prefer gravelly soils; however, there were too few data to make any gen-
eralizations (Hardy 1945). In New Mexico, the southern grasshopper mouse pre-
sumably preferred sandy soils (Bailey 1932). Grasshopper mice are reported to be
primarily carnivorous, 90 per cent of their diet consisting of animal matter (Bailey
and Sperry 1929). The predatory habits of this species may require it to forage over
large areas with little or no regard for soil or plant types.

Neotoma lepida lepida Thomas. — The desert wood rat was taken in four asso-
ciations and recorded (nests observed) for a fifth (Table 4). It was most abundant
in the SS and AC Associations where rocks were not present, but was also taken in
smaller numbers from two associations where large rocks were numerous (LD and
FD Associations). In the Owens Lake region, the presence of rocks did not seem to
be a requirement for the occurrence of Neotomal. lepida. The desert wood rat was
reported to be most abundant in rocky habitats; but occurred in other situations as
well (Hardy 1945; Fautin 1946; Hall 1946). It is probable that its occurrence is deter-
mined by the presence of adequate shelter material, vegetation or rocks.

Microtus calif ornicus vallicola Bailey. — The California meadow mouse was
not taken during this study. However, one specimen from the south shore of Owens
Lake (LSM Association) is in the Bird and Mammal Museum, California State Uni-
versity at Long Beach. In addition, runways were observed in both associations of
the Riparian Vegetation. In the Owens Valley, Microtus c. vallicola was reported
to be especially abundant along the Owens River and its tributaries (Elliott 1904;
Grinnell 1933). M. c. vallicola seemed to be restricted to the Riparian Vegetation.

Mus musculus Linnaeus. — The house mouse was taken in only one association
(SS) that was at least five miles from the nearest human habitation. The house mouse
was reported to be most commonly found in or near human dwellings; occasionally
it occurred far from them (Ingles 1965). This species probably occurs in other asso-
ciations within the study area, especially in areas where human dwellings are found,
as at Keeler and Olancha.

DISCUSSION
Distribution of Rodents

Soil texture has been considered to be a major factor influencing the local dis-
tribution of some small mammals (Hardy 1945; Fautin 1946 et. al.). This theory has
recently been questioned by Rosenzweig and Winakur (1969:561), who “. . . could

1976

The Distribution of Rodents in Owens Lake Region

21

find no patterns of mammal density or diversity using soil depths or soil particle
size”. They found structural aspects of the vegetation to be a major factor in the
distribution of small mammals. I find that both soil texture and plant cover (or vol-
ume) are important. Three species (Dipodomys deserti, Perognathus formosus and
Peromyscus crinitus) are apparently limited in their respective distributions by soil
type. D. deserti is restricted to sandy soils, the latter two to rocky soils.

Though the data are not conclusive, there does seem to be a relation between
relative abundance of some rodent species and soil texture. For example, Dipodomys
microps shows a higher relative abundance in gravelly soils than other areas where
it occurs; Perognathus longimembris was also more abundant on gravelly soils.

Structural aspects of vegetation was apparently a limiting factor for rodents
normally inhabiting Riparian situations (Mus musculus, Microtus californicus and
Reithrodontomys megalotis). Vegetation may also influence relative abundance of
rodent species; for example, Peromyscus maniculatus was more abundant in the
heavy vegetation of the Riparian than in Desert habitats. Neotoma lepida was appar-
ently restricted to those areas where structural materials were available for shelter.

Rodent Species Diversity

Species diversity can be expressed in two main ways (MacArthur 1965): 1. sim-
ple species counts; 2. some method which takes into account the abundance of each
species. The latter is usually considered to be a better method, because it differentially
ranks species into importance classes. Thus, a rare or accidental species is not given
as much importance as a more common species. Currently the most widely used
index of diversity, derived by Shannon (1948), is H = — X Pi log pj. Utilization
of H as a diversity index assumes a fairly reliable estimate of relative abundance.
Pianka (1966) has pointed out that simple species counts may prove as useful as H,
especially when there are seasonal and annual fluctuations in abundance.

Since my data are not sufficiently representative of each season, I consider the
simple species count to be a more reliable index of diversity than H. I assume the
total number of rodent species observed in each plant association is indicative of
the rodent fauna of that association. Further study in some cases may add additional
species to an association, but that should not significantly affect the general results
of this study.

The number of rodent species was compared with plant species diversity from
Table 1 and two aspects of vegetative spatial heterogeneity: per cent cover area and
plant volume diversity. Plant volume diversity was determined in the same manner
as described by Pianka (1966), utilizing H (Table 1). Only data from the Desert
Vegetation were compared.

No apparent relationship exists between plant species diversity and the number
of rodent species. This is essentially the same result as shown by Rosenzweig and
Winakur (1969) for rodents in desert situations, MacArthur and MacArthur (1961)
for birds and Pianka (1966) for desert lizards.

The number of rodent species is positively correlated with both per cent cover
area (Fig. 12) and plant volume diversity (Fig. 13). Reasons for these apparent rela-
tionships are not readily observable. One can assume increased spatial heterogeneity

22

Contributions in Science

No. 276

11-

10-

9

8-

7

6-

5-

4-

3-

.2-

1-1

• •

0—

0

5

rs = .952 (P< .01)

Y = .2l(X-7.80) + 7.25

1 1 1 1 T

10 15 20 25 30

PER CENT COVER

Figure 12. Number of rodent species versus per cent of plant cover. Spearman rank correla-
tion coefficient (rs) and linear regression equation are indicated.

(as shown by plant volume diversity) increases the number of “micro-habitats”
available to the rodents. This increased habitat complexity would allow more rodent
species to coexist.

Faunal Relationships Between Associations

The faunal relationships that exist between various plant associations can be
expressed by the following formula, utilized by Long (1963):

C(NX + N2) (100)/2N1N2 = percentage

where C = the kinds common to both associations, Nx = the number of kinds in
one association, and N2 = the number of kinds in the other association. This for-
mula was intended primarily for comparing large physiographic regions. However,
it can be utilized with good results on a smaller scale. Care must be taken when inter-
preting the results of this formula for a small geographic area. The mobility of small
mammals will tend to obscure the faunal relationships between adjacent plant asso-
ciations. A species will occasionally occur in an association it normally avoids if
its preferred habitat is nearby; for example, Dipodomys panamintinus was recorded
once from the LSM Association, which was close to the AC Association, its “pre-
ferred habitat”. Situations such as this will tend to increase the faunal relationship

1976

The Distribution of Rodents in Owens Lake Region

23

rs = .845 (P< .05)

Y = 4. 73 ( X - 1 . 231 + 7.25

1 1 1

0 1.0 2.0 3.0

PLANT VOLUME DIVERSITY

Figure 13. Number of rodent species versus plant volume diversity. Spearman rank correla-
tion coefficient (rs) and linear regression equation are indicated.

values. The results of faunal relationship analysis are given in Table 6 and graphically
represented in figure 14.

TABLE 6

FAUNAL RELATIONSHIP7

FD

LD

SA

A

SAP

SAC

AF

SS

LSM

AC

73

73

40

57

62

68

62

68

68

FD

. . .70

65

45

40

36

40

42

53

LD

. . .65

60

67

73

67

53

42

SA

. . .53

50

48

50

22

22

A

...13

86

73

47

31

SAP

...93

100

42

42

SAC

...92

51

38

AF

...42

42

SS

...78

7 See text for explanation.

U

LU

Q_

*/> 7-

i—

Z /

LU O'

Q

o

“ 5-

:> 3
z>

Z o

#/

/

/

• /

/

/

• •/

/

/

/

/

/

/

/

/

/ •

/ • •

The greatest difference (lowest values) occurred between the Desert Shrub Veg-
etation (except SA) and the Riparian Vegetation. There are high values, indicating

24

Contributions in Science

No. 276

PER CENT SIMILARITY

50 60 70 80 90 100

I I I i L l

Figure 14. Similarity phenograms of rodent species in the plant associations (see text for
explanation).

close relationships, between the AC Association and the two associations of the
Riparian Community. This is probably caused by their proximity to one another.

Highest relationship values occurred in the three plant associations having
sandy soils: SAP, SAC and AF Associations. Associations that occurred on rocky
soils — FD, LD and SA — did not show such high values.

The greatest differences within the Desert Shrub Community occurred between
associations found on different soil types (sandy versus rocky soils). The LD Asso-
ciation was an exception, showing a high relationship to associations with sandy
soils.

The two associations occurring on gravelly soils (AC and A) had a low faunal
relationship. This is probably because the A Association was the poorest producer
of rodents.

The two associations of the Riparian Community showed a high faunal rela-
tionship, as would be expected.

Biogeographical Comments

The 16 native species of rodents inhabiting the Owens Lake Region do not
show the same ecotonal relationships as do the plants (see introductory paragraph).

1976

The Distribution of Rodents in Owens Lake Region

25

Most species are of widespread occurrence in both northern and southern deserts.
However, inspection of range maps in Hall and Kelson (1959) shows most of the
species have their greatest distribution south of Owens Valley and may have invaded
the valley from the south.

Two species, Dipodomys microps and Peromyscus crinitus, have more exten-
sive ranges east and north of the valley and may have invaded from those directions.

ACKNOWLEDGMENTS

I wish to thank Dr. Ross Hardy for his encouragement and advice throughout
this study. Special thanks are also given to Dean E. Harvey, Lan A. Lester and
Douglas B. Williams for their assistance at various times during the study. I am
grateful to Andrew Starred, Richard O. Friesen and Donald R. Patten for their advice
and critique of the final manuscript. Thanks go also to Robert E. Crabb for his assis-
tance in the field during the summer of 1971.

This paper represents a revision of a Masters Thesis presented to the Department
of Biology, California State University, Long Beach.

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1976

The Distribution of Rodents in Owens Lake Region

27

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Accepted for publication June 30, 1975

NUMBER 2 77
JULY 7, 1976

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RIES. The Contributions are short papers of octavo size. The Bulletins are longer, compre-
hensive papers of quarto size. The Series are papers of variable lengths of quarto or larger
size. Papers in each serial are numbered separately and consecutively.

CONTRIBUTIONS IN SCIENCE contain articles in the earth and life sciences, presenting
results of original research. Emphasis is intended principally for papers allied to biosystematic
research, but other subjects and review-oriented ones will be considered. Number 1 was issued
on January 23, 1957. Contributions must be not less than 8 nor exceed 72 printed pages.

INSTRUCTIONS FOR AUTHORS

Acceptance of manuscripts will be determined by the significance of new information. Priority
will be given to manuscripts by staff members. All manuscripts must be recommended by the
curator in charge of each discipline or by the Editorial Board. Manuscripts must conform to
the specifications listed below. They will be examined for suitability by the Editorial Board
and will include review by specialists outside the Museum.

Authors must adhere to the International Code of Nomenclature of Bacteria and Viruses,
International Code of Botanical Nomenclature, and International Code of Zoological Nomen-
clature, including their respective recommendations. Further, authors proposing new taxa in
a CONTRIBUTIONS IN SCIENCE must indicate that all primary types have been deposited
in an appropriate scientific institution of their choice and must cite that institution by name.

MANUSCRIPT FORM. — (1) In preparation of copy follow the 1972 CBE Style Manual,
third edition (AIBS), Chapters 5 and 6. (2) Footnotes should be avoided; acknowledgments
as footnotes will not be accepted. (3) An informative abstract must be included for all papers.
(4) A Spanish summary is required for all manuscripts dealing with Latin American subjects.
Summaries in other languages are not required but are strongly recommended. (5) A differ-
ential diagnosis must accompany any newly proposed taxon. (6) Submit two copies of manu-
script.

ILLUSTRATIONS. — All illustrations, including maps and photographs, will be referred to
as figures. All illustrations should be of sufficient clarity and in proper proportions for reduc-
tion to CONTRIBUTIONS page size. In preparing illustrations and legends consult the 1972
CBE Style Manual, third edition (AIBS), Chapter 5. Submit only illustrations made with
permanent ink and glossy photographic prints of good contrast. Submit duplicate copies of
all illustrations. Original illustrations will be returned after the manuscript has been published.

PROOF. — Authors will be sent galley proofs which should be corrected and returned promptly.
No changes or alterations, other than typesetting corrections, will be allowed unless paid by
author. Requests for reprints may be placed through the Editor.

R. Edward Ostermeyer
Editor

All communications concerning manuscripts and exchange of or purchase of publications
should be sent to the Editor, Museum Publications, Natural History Museum of Los Angeles
County, 900 Exposition Boulevard, Los Angeles, California 90007.

Printed in the United States of America by Chapman’s Phototypesetting on 70# Patina Book

COMMENTS ON BATS NEWLY RECORDED FROM COSTA RICA1

By Andrew Starrett2

Abstract: Micronycteris nicefori, M. brachyotis, and Diphylla ecaudata are
reported for the first time from Costa Rica, and the ranges of these species are sum-
marized. The molt pattern of M. nicefori is described and the two color phases of
this species are explained on the basis of an apparent annual molt-hair discolora-
tion sequence.

INTRODUCTION

In 1970 and 1971, more than 55 species of bats were collected in Costa Rica
by students working in courses under the, program of the Organization for Tropical
Studies (OTS). Three, which are new to the recorded fauna of Costa Rica, are re-
ported here. They were taken on the Osa Peninsula, Provincia de Puntarenas, in
1970, and at Finca Jimenez (Ministerio de Agricultura y Ganaderia, Estacion Experi-
mental “Finca Jimenez Nunez”), Prov. Guanacaste, in 1971. Also included are
specimens of two of these species which were collected at Finca La Pacifica, Prov.
Guanacaste, by Theodore H. Fleming, and at Finca Jimenez, by Thomas B. Keyse,
during the course of separate projects in 1971 and 1972. The specimens are now
in collections at the Natural History Museum of Los Angeles County (LACM),
the Museum of Southwestern Biology, University of New Mexico (MSB) and the
University of Missouri, St. Louis (THF).

All measurements of specimens are in millimeters. Capitalized Forest Forma-
tion designations are those of L. R. Holdridge (Tosi 1969).

The sites of capture for the specimens from Finca Jimenez were in riparian
forest along the Rio Higueron. Both Finca Jimenez and Finca La Pacifica are in the
lowland Pacific Tropical Dry Forest region of western Costa Rica; the locality on
the Osa Peninsula is in lowland Pacific Tropical Wet Forest, some 260 km to the
southeast.

CAPTURES AND COMMENTS

Micronycteris nicefori Sanborn. — Two adult males were caught by O.T. S.
students in nets set across the Rio Higueron (elev. 10 m) at Finca Jimenez. One was
taken on the night of April 21-22, 1971, during the dry season when the river bed
was for the most part dry; the second was caught on June 8, 1971, in the early part
of the rainy season when the river was flowing. Three additional adult males were

Review Committee for this Contribution
James S. Findley
Donald R. Patten
Don E. Wilson

2Research Associate, Section of Mammalogy, Natural History Museum, and Department of
Biology, California State University, Northridge, California 91324

2

Contributions in Science

No. 277

caught by Thomas B. Keyse, in May and June 1972, in the forest on the south side
of the same river, not far from the place of capture of the first two.

In all essential characters and most measurements, the specimens from Costa
Rica agree closely with those given in Sanborn’s description of the species. In the
original description, Sanborn (1949) indicated that his series of five specimens (in
alcohol) showed “a gray and a red phase,” the holotype being “near Olive Brown
above” and the “darkest specimen near Walnut Brown above.” He also mentioned
“a faint light gray line” on the lower back of all specimens. No light gray line is
present on any of the specimens from Costa Rica, and this character appears to be
variable over the range of the species (Goodwin and Greenhall 1961; Ojasti 1966).
The range of color in the five males from Costa Rica shows variation which appar-
ently represents a molt and discoloration cycle similar to that described by Smith
(1972) for Pteronotus parnellii. The specimens of Micronycteris nicefori, which
were all taken from essentially the same locality on five different dates from late
April to early June in two successive years, range from a “red phase” (April 22)
through a reasonably date-correlated molt progression to a “gray phase” (June 8).
One specimen was collected on a later date (June 30) and showed an active inter-
mediate molt condition. The red phase pelage, which is somewhat more orange
than Sanborn’s “Walnut Brown” specimen (if the two copies of Ridgway 1912,
which I consulted, and which differ one from the other in some colors, show the
same colors seen in the copy used by Sanborn in 1949), seems to represent chem-
ically altered coloration of the dark olive brown fur attained in what apparently is
the single annual molt which takes place, in Costa Rica at least, from April through
June or July. Sanborn’s specimens (1 6 , 4??) were collected in January and repre-
sent a similar series which would indicate an earlier molt for this species in Colum-
bia. Five specimens caught in August in Amazonian Peru \/ere “olivatre” (Pirlot
1968), and three taken in Venezuela, a male and female in November and another
female in May, were described as “matron anaranjada” (Ojasti 1966, using Villa-
lobos and Villalobos 1947, color designations). That these specimens represent
the olive-brown and red color phases seems indicated, but whether they support
the proposed interpretation of color phases in this species, perhaps modified by
local factors and/or reproductive condition (Smith 1972), cannot be determined
for certain with the limited information available. A relationship between repro-
ductive state and molt pattern is suggested by the fact that in the specimens from
Costa Rica which show hair replacement in progress, the chest gland is prominent
and presumably active (representing reproductive activity?), whereas in the animal
from June 8, which shows no remnant of red phase hair, the gland is not discernible
from superficial examination. The timing of male activity is in line with that sug-
gested by data presented by Fleming, Hooper and Wilson (1972) for other species
in the same general locality.

In the Costa Rican series, dorsal molt progression begins around the eyes
(already brown in the April specimen), then proceeds mainly by a gradual inter-
mixture of new hairs and subsequent sloughing of old hairs over the head, and then
from the shoulders and interscapular area posteriad, with the fur of the sides and
middle back leading the progression. Ventrally, the molt pattern is more clearly

1976

New Costa Rican Bat Records

3

defined with a loss-replacement sequence which starts below the ears and on the
mid-abdominal area (light gray- brown hairs characteristic of gray phase ventral
pelage present in the under-ear area and a few small patches on the abdomen in
the April specimen), then expands laterad and posteriad from the throat and mid-
venter, the orange fur under the wings between humerus and femur being the last
to go. Especially noticeable dorsally is a frosted appearance caused by hairs with
silvery-white tips (not noted by Sanborn 1949) which gradually change to a silvery-
yellow in the red phase. During the molt sequence these hairs appear to be lost first,
leaving dark-tipped red hairs that give the pelage a dull, worn look. In some areas
the new silver-tipped brown hairs become apparent before the dull red pelage is
gone, and closer examination shows the less obvious new darker-tipped brown hairs
coming in as well. This intermixing of red and brown hairs gives the pelage an
intermediate red-brown tone which suggests at first glance a third “color phase.”

Selected measurements of the Costa Rica specimens are: (LACM 38542, 38543;
MSB 32537, 32538, 32539) forearm, 36.4, 38.2, 38.7, 35.1, 37.5; (LACM speci-
mens) metacarpal III, 33.3, 34.5; metacarpal IV, 30.8, 31.5; metacarpal V, 31.7,
33.0; (LACM 38543) greatest length of skull, 20.9; condylobasal length, 18.6;
zygomatic width, 9.5; postorbital constriction, 4.5; maxillary tooth row, 7.4; width
across upper canines, 3.4; width across M3-M3, 6.3.

Since Sanborn described Micronycteris (Trinycteris) nicefori from northern
Colombia in 1949, it has been reported from Trinidad (Goodwin and Greenhall
1961), Guyana (Hill 1964), Venezuela (Ojasti 1966), Panama (Handley 1966) and
the upper Amazon of Peru (Pirlot 1968). The locality nearest to the Costa Rican site
reported here is Fort Gulick, Canal Zone (Handley 1966:760) some 600 km to the
southeast.

Micronycteris brachyotis (Dobson) (=M. platyceps Sanborn). — An adult
female (forearm 43) was caught in a net placed across the dry bed of the Rio Higu-
eron, Finca Jimenez, on the night of April 21-22, 1971, and then banded and re-
leased. Three members of this species were also banded and released, in 1970-1971,
at Finca La Pacifica (approx, elev. 40 m), some 20 km NNE of Finca Jimenez (Flem-
ing et al. 1972), and two more, an adult male (forearm 41.0) and a weanling juvenile
male (forearm 28) from the same locality, were saved as a skin and skull and alcoholic
specimen, respectively (THF).

The yellow -throated bat was previously known from a scattering of localities
in Oaxaca and Chiapas, Mexico (Davis et al 1964; Schaldach 1964), Guatemala
(Jones 1966; Rick 1968), Nicaragua (Sanborn 1949), Panama (Handley 1966),
Colombia (Marinkelle and Cadena 1972), Venezuela (Sanborn 1949), French Guiana
(Sanborn 1949; Cayenne, type locality of Schizostoma brachyote Dobson), Trinidad
(Sanborn 1949; Goodwin and Greenhall 1961; Guanapo, type locality of Micro-
nycteris (Lampronycteris) platyceps Sanborn) and Brasil (Goodwin and Greenhall
1961: 231).

Diphylla ecaudata Spix. — An adult female was netted, on August 4, 1970,
near the Tropical Science Center building and not far from the airstrip for Rincon
de Osa. The net in which the animal was captured was set in relatively undisturbed
forest, some 25 m from the Rio Agua Buena (approx, elev. 15 m).

4

Contributions in Science

No. 277

This species is known from a scattering of localities ranging from southern
Texas (Reddell 1968) through Middle and South America to southern Brasil (Cabrera
1957; Hall and Kelson 1959; Villa-R. 1966). In Central America, it has been re-
corded previously from every country except Belize and Costa Rica (Goodwin 1942b;
Burt and Stirton 1961; Handley 1966; Jones 1966; Jones et al 1971). Nowhere
does it seem to be abundant, apparently being less influenced by concentrations of
domestic animals than is Desmodus. It also appears to have more of a preference
for humid environments than does the latter, being associated, in Central America,
at least, with lowland evergreen forest.

The forearm measurement (57.2) of the Costa Rican specimen (LACM 33180)
falls in the middle of the range for females given by Burt and Stirton (1961). I
prefer to follow these authors (also Handley 1966, and Jones et al 1971) in con-
sidering Diphylla ecaudata monotypic, even though Ojasti and Linares (1971)
have renewed support for the separate recognition of Middle American popula-
tions (based on a comparison of measurements of South American specimens with
those given by Burt and Stirton 1961). The wide range of measurements shown
by Villa-R. (1966) for this species in Mexico suggests the desirability of a more
inclusive review of specimens from Middle America before basing any judgments
on size characteristics.

ACKNOWLEDGEMENTS

I thank Roy W. McDiarmid, University of South Florida, for specimens, rec-
ords and field data from Finca Jimenez, and for reading and commenting on the
manuscript. Inclusion of the records and information concerning the Micronycteris
nicefori in the collection of the Museum of Southwestern Biology was made possible
through the courtesy of Thomas B. Keyse, James S. Findley and Kim Mortensen,
University of New Mexico; Theodore H. Fleming, University of Missouri, St. Louis,
very kindly made available to me the specimens of Micronycteris brachyotis, with
appropriate field notes, from Finca La Pacifica.

RESUMEN

Por primera vez se reportan tres epecies de murcielagos de Costa Rica: Mi-
cronycteris brachyotis, Micronycteris nicefori y Diphylla ecaudata. Las primeras
dos especies provienan de localidades de la Provincia de Guanacaste, la tercera
proviene de la Peninsula de Osa, Provincia de Puntarenas. En el presente informe
se esquematiza la distribucion de estas especies y se describe el patron de muda para
M. nicefori. Se sugiere que las dos fases de coloracion en esta especie representan
los extremos de una continua secuencia de muda y decoloracion quimica del pelaje.

LITERATURE CITED

Burt, W. H., and R. A. Stirton. 1961. The mammals of El Salvador. Univ. Mich. Mus.

Zool., Misc. Publ., No. 117:1-69.

Cabrera, A. 1957. Catalogo de los mamiferos de America del Sur. I. Mus. Argent. Cienc. Nat.

“Bernardino Rivadavia,” Cienc. Zool., Rev., 4:1-307.

1976

New Costa Rican Bat Records

5

Davis, W. B., D. C. Carter, and R. H. Pine. 1964. Noteworthy records of Mexican and Cen-
tral American bats. J. Mammal., 45:375-387.

Fleming, T. H., E. T. Hooper, and D. E. Wilson. 1972. Three Central American bat commu-
nities: structure, reproductive cycles and movement patterns. Ecol., 53:555-569.
Goodwin, G.G. 1942. Mammals of Honduras. Amer. Mus. Nat. Hist., Bull., 79:107-195.

, and A. M. Greenhall. 1961. A review of the bats of Trinidad and Tobago. Amer.

Mus. Nat. Hist., Bull., 122:187-302.

Hall, E. R., and K. R. Kelson. 1959. The mammals of North America.- Vol. I. Ronald Press,
N. Y. 546 p.

Handley, C. O., Jr. 1966. Checklist of the mammals of Panama, pp. 753-795. In Wenzel, R.

L., and V. J. Tipton, Ectoparasites of Panama. Field Mus. Nat. Hist., Chicago. 861 p.
Hill, J. E. 1964. Notes on bats from British Guiana, with the description of a new genus and
species of Phyllostomidae . Mammalia, 28:553-572.

Jones, J. K., Jr. 1966. Bats from Guatemala. Univ. Kans. Publ. Mus. Nat. Hist., 16:441-472.

, J. D. Smith, and R. W. Turner. 1971 . Noteworthy records of bats from Nicaragua,

with a checklist of the chiropteran fauna of the country. Mus. Nat. Hist., Univ. Kans., Occ.
Pap., No. 2:1-35.

Marinkelle, C. J., and A.Cadena. 1972. Notes on bats new to the fauna of Colombia.
Mammalia, 36(l):50-58.

Ojasti, J. 1966. Cuatro nuevos murcielagos para la fauna Venezolana. Acta Biol. Venez.,
5:91-97.

, and O.J. Linares. 1971. Adiciones a la fauna de murcielagos de Venezuela con

notas sobre las especies del genero Diclidurus (Chiroptera). Acta Biol. Venez., 7:421-441.
Pirlot, P. 1968. Chiropteres du Perou, specialment de Haute- Amazonie. Mammalia, 32:86-95.
Reddell, J. R. 1968. The hairy-legged vampire, Diphylla ecaudata, in Texas. J. Mammal.,
49:769.

Rick, A.M. 1968. Notes on bats from Tikal, Guatemala. J. Mammal., 49:516-520.

Ridgway, R. 1912. Color standards and color nomenclature. Washington, D.C., publ. by
author. 43 p., pi. I-LIII.

Sanborn, C. C. 1949. Bats of the genus Micronycteris and its subgenera. Field. Zool., 31: 215-
230.

Schaldach, W. J., Jr. 1964. Notas breves sobre algunos mamiferos del sur de Mexico. Inst.
Biol., Univ. Mexico, An., 35:129-137.

Smith, J. D. 1972. Systematics of the chiropteran family Mormoopidae. Univ. Kans. Mus. Nat.
Hist., Publ. No. 56, 132 p.

Tosi, J. A., Jr. 1969. Republica de Costa Rica, Mapa Ecologico. Tropical Science Center,
San Jose.

Villa-R., B. 1966. Los murcielagos de Mexico. Inst. Biol., Univ. Nac. Auton. Mexico.
491 p.

Villalobos, D.O., and J. Villalobos. 1947. Altas de colores. El Ateneo, Buenos Aires,
I-XV, 1-74, pi. 1-38 (citation from Ojasti, 1966).

Accepted for publication January 7, 1975.

5 07. 73
C a./ L 8&Z

NUMBER 278
AUGUST 30, 1976

LIVING CHAMIDAE OF THE EASTERN PACIFIC
(BIVALVIA: HETERODONTA)

By F. R. Bernard

NATURAL HISTORY MUSEUM OF LOS ANGELES COUNTY

CONTRIBUTDNS IN SCENC6

j| 1 :

f ?15 r...

'r;1 ■

Published by the NATURAL HISTORY MUSEUM
OF LOS ANGELES COUNTY
900 Exposition Boulevard, Los Angeles, California 90007

SERIAL PUBLICATIONS OF THE
NATURAL HISTORY MUSEUM OF LOS ANGELES COUNTY

Prior to November 30, 1973, publications of the Natural History Museum have appeared
under various formats — Leaflet Series, Museum Graphic, Science Series, Study Guides, Con-
tributions in Science, Contributions in History, Science Bulletins, unnumbered catalogs of
exhibitions, and other miscellaneous publications. The Museum now publishes the following
serials at irregular intervals as CONTRIBUTIONS IN SCIENCE, HISTORY BULLETINS,
SCIENCE BULLETINS, EDUCATION SERIES, HISTORY SERIES, and SCIENCE SE-
RIES. The Contributions are short papers of octavo size. The Bulletins are longer, compre-
hensive papers of quarto size. The Series are papers of variable lengths of quarto or larger
size. Papers in each serial are numbered separately and consecutively.

CONTRIBUTIONS IN SCIENCE contain articles in the earth and life sciences, presenting
results of original research. Emphasis is intended principally for papers allied to biosystematic
research, but other subjects and review-oriented ones will be considered. Number 1 was issued
on January 23, 1957. Contributions must be not less than 8 nor exceed 72 printed pages.

INSTRUCTIONS FOR AUTHORS

Acceptance of manuscripts will be determined by the significance of new information. Priority
will be given to manuscripts by staff members. All manuscripts must be recommended by the
curator in charge of each discipline or by the Editorial Board. Manuscripts must conform to
the specifications listed below. They will be examined for suitability by the Editorial Board
and will include review by specialists outside the Museum.

Authors must adhere to the International Code of Nomenclature of Bacteria and Viruses,
International Code of Botanical Nomenclature, and International Code of Zoological Nomen-
clature, including their respective recommendations. Further, authors proposing new taxa in
a CONTRIBUTIONS IN SCIENCE must indicate that all primary types have been deposited
in an appropriate scientific institution of their choice and must cite that institution by name.

MANUSCRIPT FORM. — (1) In preparation of copy follow the 1972 CBE Style Manual,
third edition (AIBS), Chapters 5 and 6. (2) Footnotes should be avoided; acknowledgments
as footnotes will not be accepted. (3) An informative abstract must be included for all papers.
(4) A Spanish summary is required for all manuscripts dealing with Latin American subjects.
Summaries in other languages are not required but are strongly recommended. (5) A differ-
ential diagnosis must accompany any newly proposed taxon. (6) Submit two copies of manu-
script.

ILLUSTRATIONS. — All illustrations, including maps and photographs, will be referred to
as figures. All illustrations should be of sufficient clarity and in proper proportions for reduc-
tion to CONTRIBUTIONS page size. In preparing illustrations and legends consult the 1972
CBE Style Manual, third edition (AIBS), Chapter 5. Submit only illustrations made with
permanent ink and glossy photographic prints of good contrast. Submit duplicate copies of
all illustrations. Original illustrations will be returned after the manuscript has been published.

PROOF. — Authors will be sent galley proofs which should be corrected and returned promptly.
No changes or alterations, other than typesetting corrections, will be allowed unless paid by
author. Requests for reprints may be placed through the Editor.

R. Edward Ostermeyer
Editor

All communications concerning manuscripts and exchange of or purchase of publications
should be sent to the Editor, Museum Publications, Natural History Museum of Los Angeles
County, 900 Exposition Boulevard, Los Angeles, California 90007.

Printed in the United States of America by Chapman’s Phototypesetting on 70# Patina Book

LIVING CHAMIDAE OF THE EASTERN PACIFIC
(BIVALVIA: HETERODONTA)1

By F. R. Bernard2

Abstract: Nineteen species of Chamidae live in the American Eastern Pacific
and occur predominantly in shallow warm waters. The extensive collections of
the Allan Hancock Foundation, University of Southern California, provided the
basis for this distributional and systematic review. It is concluded that the valve
of attachment is genetically determined. A reinterpretation of hinge ontogeny is
presented. Pseudochama dalli nom. nov. is proposed for a preoccupied name.
Three new species, Chama arcana, C. garthi, and C. tinctoria are proposed.

INTRODUCTION

The Superfamily Chamacea is represented by the single family Chamidae,
comprising epithetic (attached) dimyarian bivalves inhabiting shallow tropical to
temperate waters. Maximum abundance is just sublittoral, though a few species
have been collected down to 200 meters; deep records such as 2300 meters (Locard
1898) for Chama nicoloni Dautzenberg, 1892 are probably attributable to trans-
ported material (Clarke 1962). The largest and most diverse faunule is Indo-Pacific.
Approximately 70 living species are represented world-wide of which 19 are east-
ern Pacific.

The amount of chamid literature is small and scattered. The modern com-
prehensive taxonomic treatment is that by Lamy (1927), while anatomical and
systematic reviews by Odhner (1919) and Yonge (1967) reached somewhat con-
tradictory conclusions. Bayer (1943) reviewed some Caribbean species. In the
course of preparing a world- wide survey of the family, the large holdings of the
British Museum (Natural History), the Paris Museum, the Stockholm Rijksmuseet,
and the United States National Museum, were studied and compared, as well as
material in the California Academy of Sciences, Los Angeles County Museum
of Natural History, and the S. S. Berry collection. This paper is based upon the
important West American collections made since 1931 by the Allan Hancock Foun-
dation and its predecessor, the Hancock Pacific Expeditions, which have yielded
new distributional records, three new species, and a sufficient series of juvenile
specimens to clarify probable hinge ontogeny.

Review Committee for this Contribution
Kenneth J. Boss
Myra Keen
James H. McLean

2Research Associate in Malacology, Natural History Museum of Los Angeles County, and
Environment Canada, Fisheries and Marine Service, Pacific Biological Station, Nanaimo,
B.C., Canada. V9R 5K6

o

Contributions in Science

No. 278

Cham ids are generally highly inequivalve, with strongly prosogyrate beaks.
During development the beaks become separated, resulting in the longitudinal split-
ting of the substantial parivincular ligament. The external shell surface may be orna-
mented with regular lamellae or spines or may be entirely smooth, particularly in
gerontic specimens. Cup-shaped outgrowths analogous to the hyote spines of some
Indo-Pacific pycnodontid oysters are usually present on the cemented valve and
probably serve as supports for sensory folds of mantle tissue (Rudwick 1965). The
commissural outline is usually rounded but may be elongate, particularly in Pseu-
dochama. In nearly all species the commissure margins display a flattened area
set off at an obtuse angle from the general curve of the internal shell surface. This
region is analogous to the commissural shelf of some oysters and consists of the
outer and middle shell layers only, and may be crenulated or nodulose.

Chamids are either permanently cemented to the substrate or undergo a brief
phase of attachment during development. In all genera the unattached valve car-
ries a single laterally elongated tooth-like process that fits into a socket in the
attached valve. While the juvenile dentition displays a generalized heterodont
pattern, adult dentition is entirely different. Attempts to homologize the mature
configuration to early dissoconch hinge structures have led to unsatisfactory
conclusions and inability to resolve the systematic significance of the valve of
attachment.

All the permanently attached chamids are strongly inequivalve, the free valve
often being little more than a discoid operculum closing off the large cup-shaped
attached valve. This group is extremely xenomorphic, moulding to the substrate
and losing most external characters such as spines in mature specimens. The non-
cemented genus Arcinella displays a well-developed lunule that is absent in other
taxa, but some attached chamids have a trace of an obscure escutcheon on the free
valve. In all groups the ligament is external, but may be deeply sunk and over-
grown by the outer shell layers.

Chamids are stenohaline nearshore inhabitants of rocky shores and coral reef
communities. Their poor ability to withstand lowered salinity prevented their col-
onization of estuarine regions. Their distribution is limited to areas with little sedi-
mentation, and habitats fall into two major categories. The greater number of
species are cemented to massive rocks in exposed areas, from the mid-tidal zone
to a few meters depth. These individuals are large, thick-shelled and bear little shell
ornamentation. The other group comprises the smaller, thin shelled species with
small areas of attachment and pronounced shell ornamentation. These individuals
live as nestling epifauna, frequenting fissures and crannies, as well as the underside
of boulders. This group has a wider bathymetric range than the first, frequently
occurring in 20 or more meters, cemented to small pebbles, shells, or coral.

It is now well established that chamids and the extinct rudists had no common
phylogenetic links, yet the distribution and ecological niche of the two taxa is strik-
ingly similar. Dacque (1915) noted the low latitude circumglobal distribution of
rudists, an observation strengthened by Hamilton’s (1956) discovery of rudists
dredged from Cape Johnson guyot in the mid-Pacific.

1976

Eastern Pacific Chamidae

3

Despite their wide tropical and subtropical distribution, chamids remained
conservative in habitat selection, no representatives have been reported in such
niches as mangrove roots or floating debris so successfully colonized by other
cemented forms. The only experiment appears to be the pseudochamid-descended
genus Arcinella, which adopted a free existence when adult. It is doubtful if this
may be considered a true adaptation, as detachment is purely mechanical, the result
of the initial small attachment zone. However, the nearly equivalve condition and
the great development of the shell spines are probably contributive to successful
free epiphetic existence. The experiment cannot be considered an unqualified suc-
cess as Arcinella is very limited in distribution and is of rare occurrence.

Anatomy

The gross morphology of the Chamidae is well known from the work by Grieser
(1913), the comparative studies by Odhner (1919), and the functional interpreta-
tion of Yonge (1967). Only a brief summary is given here based upon observation
of preserved Chama squamuligera Pilsbry and Lowe; Pseudochama corrugata
(Broderip), and a single specimen of Arcinella californica (Dali).

Chamid soft parts, with the exception of Arcinella , are bilaterally asymmet-
rical, being hypertrophied on the side of attachment; the mantle, ctenidia, gonad
and digestive diverticula are enlarged, though the balance of the alimentary, circu-
latory, and nervous systems are not affected. The ventral migration of the adult
functional hinge results in the formation of a deep umbonal cavity, occupied by a
prolongation of the mantle, gonad, and connective tissues, similar to that of some
Ostreacea. The nature of this body asymmetry has been fully discussed by Yonge
(1967).

The mantle is thin, with small marginal folds. Fusion is extensive but involves
only the inner fold, except for the dorsal portions, where both the inner and middle
folds are fused. The fused border is outside the hinge line and lies just below the
ligament, so that an extensive epithelial sheet separates the opposing hinge elements.
This interdental epithelium is fenestrated, the openings conforming to the protuber-
ances on the teeth, which are analogous to vermiculate chomata (Stenzel 1971).
The presence of a nacre-secreting mantle edge outside the hinge teeth is the main
factor leading to the formation of an annular free valve with progressive centraliza-
tion of the hinge teeth.

The fused mantle borders are furnished with irregularly distributed small tenta-
cles, which are longest in Arcinella. Two small thin papillated siphons arise just
below the posterior adductor muscle, while the pedal opening occupies most of the
anterior face of the anterior adductor muscle. In Arcinella the pedal opening is
smaller and more ventrally situated, the siphons larger and more muscular. The
large adductor muscles are subequal and dorsoventrally elongated. The foot in
Chama and Pseudochama is virtually vestigial and probably not functional. In
Arcinella it is vermiform and capable of protrusion through the pedal opening.

Chamid ctenidial structure has been exhaustively covered by Menegaux (1890),
Ridewood (1903), Grieser (1913), Odhner (1919) and others. This organ is re-

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markably uniform in all three genera, and consists of two complete demibranchs,
the inner one larger than the outer. The lamellae are plicated, synaptorhabdic,
with both interfilamentar and interlamellar junctions as well as intraplicatural
fusions involving the distal ends of opposing filaments (Ride wood 1903). Cteni-
dial ciliation falls under “Type C” of Atkins (1937), and Yonge (1967) has dealt
with ciliary currents.

The labial palpi are asymmetrically placed and small in Chama and Pseudo-
chama, and much larger in Arcinella. The mouth is wide and overhung by pro-
truding lips. The rest of the alimentary canal is similar in all taxa. A slender plicated
oesophagus enters the anterior portion of the stomach, separated from the stomach
main chamber by a conspicuous ventral ridge. Crystalline style-pouch and midgut
are conjoined. The minor typhlosole terminates on the stomach’s right posterior
wall, while the major typhlosole, accompanied by the intestinal groove, curves
over the left wall and terminates near the openings of the digestive diverticulae. A
small dorsal hood is situated on the anterior left side of the stomach. The ducts
of the digestive diverticula number about eight and are clustered into four groups.
The gastric shield is small. The chamid stomach falls into “Type IV’’ of Purchon
(1958).

The intestine is short, passes dorsally through the ventricle of the heart, then
plunges ventrally along the outer surface of the posterior adductor muscle. The
anus is removed from the exhalant siphon, so it is possible that faeces are trans-
ported by ciliary currents and discarded via the pedal aperture. Odhner (1919)
reported variations in intestinal flexure; however, these are probably attributable
to indifferent specimen preservation. The specimens examined for this report all
conform to the description of Yonge (1967). Pelseneer (1911) claimed partial rever-
sion of the alimentary canal in Chama and Pseudochama; however, Odhner (1919)
did not support this view and Yonge (1967) showed that “inversion” involved the
pallial structures only.

The family is dioecious, the extensive gonads occupying the lateral portions
of the body, the umbonal cavity, and the dorsal mantle tissues. The eggs are small,
fertilization occurs externally, and the larvae probably undergo a prolonged plank-
tonic development (LaBarbera and Chanley 1971).

Cementation

Cementation is usually associated with the monomyarian condition; living
cemented dimyarians consist only of the Chamidae, Myochama, Dimya and the
freshwater Etheriidae. In the Chamidae cementation occurs late in the dissoconch
stage (sometimes termed the post-neanic), individuals being 0.5-5 mm total shell
length, depending upon ultimate species size. Subsequent to planktonic develop-
ment, larvae are mobile and temporarily attach by a single byssal thread (LaBarbera
and Chanley 1971). Anthony (1905) believed cementations occurred either ante-
riorly or by the entire valve surface, resulting in an oblique elongated or rounded
adult form. However, examination of large series of recently attached individuals
and the report by LaBarbera and Chanley (1971) clearly show that cementation is

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5

not pleurothetic but involves the new growth margin and results in the anteroposte-
rior axis being perpendicular to the substrate. A period of rapid idiomorphic growth
occurs with a strong tangential component in the attached valve which undergoes
a coiling growth. The early stages of cementation are presented diagrammatically
in figure 1. The more rapid addition to the attached valve results in the progres-
sive separation of the beaks, so that the dissoconch commissural planes come to
lie at right angles to each other. The spatial displacement of the umbones causes the
longitudinal splitting of the ligament, a process fully described by Owen (1953)
and Yonge (1967).

The size of the cementation area bears a direct relationship to the curvature
of the two shell valves. If it is extensive, the shell is highly inequivalve with a flat-

Figure 1. Cementation and early growth of Pseudochama. (a) Initial attachment; (b) period of
rapid idiomorphic growth; (c) assumption of adult form. l.v. = left valve; r.v. = right valve,
scale = 1 mm.

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tened opercular free valve. Jackson (1890), in a largely overlooked paper, first
concluded that mechanical constraints of cementation resulted in a cup-shaped
attached valve. Subequivalve chamids such as C. sordida Broderip and C. corallina
Olsson display small cementation zones as does the nearly equivalve genus Arcinella.

Lamarck (1819) segregated chamids according to which valve was cemented
to the substrate, but Broderip (1835a) failed to distinguish between them, while
Reeve (1847) stated that attachment was fortuitous. The systematic significance
of left or right valve attachment has not been resolved, though Odhner (1919) di-
vided the permanently cemented Chamidae into two genera. While agreeing that
most representatives are consistently attached either by the left or right valve, Lamy
(1927) placed all species in Chama. Yonge (1967) also rejected the taxonomic sig-
nificance of attachment, but admitted the convenience of referring to Chama and
Pseudochama.

Which valve is cemented to the substrate is genetically determined and appar-
ent anomalies are nearly all referable to misidentifications. For example the type
specimens of the Indo-Pacific C. pulchella said by Reeve (1847) to be indifferently
attached (Syntypic Series BM(NH) 1950. 11.1 49-51) certainly consists of two
species, the smaller individuals, the nominate species; and the larger specimen is
P. similis Odhner 1917. The attached left and right valves figured by Palmer (1928),
said to be C. pellucida Broderip, represent typical specimens of this species and
of P. exogyra (Conrad), whose ranges overlap. Taylor and Kennedy (1969) re-
peated the observation that C. pellucida may sometimes attach by the right valve.
I have examined long series of this species without noting a single case of anomalous
attachment. Yonge (1967) stated that Chama radians Lamarck may be cemented
by either valve, but I was unable to locate any material in the British Museum.
Nicol (1952a) reported only one specimen of one thousand A. arcinella that ap-
peared to be attached by the right valve.

Hinge Dentition and Reversal

Munier-Chalmas (1882) and Bernard (1895, 1897) examined the chamid
hinge and attempted to homologize it with heterodonts while suggesting a dental
formula notation. Dali (1903b) presented an illustration purporting to be a juve-
nile C. pellucida showing radiating cardinals and laterals. Odhner (1919) believed
it to be a juvenile Arcinella; however I do not consider it to be chamid and have
been unable to trace the specimen in the USNM. The first full description of the
dentition of juvenile chamids is given by Anthony (1905) and its undoubted hetero-
dont affinity revealed.

Munier-Chalmas (1882) demonstrated that dentition can be “normal” or
“inverse” so that the arrangement of the teeth of the attached valve is similar;
whether it be a right or left valve, and the dental elements are mirror images of
each other (Yonge 1967). This inversion affects only the shell and hinge morphol-
ogy; other systems (alimentary, nervous, etc.) are not reversed. Not only are at-
tached bivalves very consistent in the valve by which they attach, but transposition

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7

of hinge elements is extremely rare. It has been suggested by various authors that
at first adoption cementation may have occurred indifferently by either valve, but
would become set later in the history of a species. Termier and Termier (1949)
stated that Triassic oysters attached by either valve, but Newell and Boyd (1970)
failed to find any well documented cases for Middle and Lower Triassic oyster-
like bivalves. Odhner (1919, 1955) thoroughly reviewed the literature and cor-
rectly disposed of most reports of hinge reversal. Most inversions involve only
part of the hinge structure and are probably teratological. Popenoe and Findlay
(1933) could cite no example of complete transposition, though Hanna (1925) men-
tioned a case of complete inversion in an Eocene Venericardia and Eggleton and
Davies (1961) noted a small percentage of reversion in some Sphaeriids.

Development of Adult Dentition

Adult dentition is different from the juvenile heterodont phase. Grant and
Gale (1931) state that the hinge teeth “. . .are replaced by rather crude and heavy
rugosities. ...” Added to the impracticability of homologizing adult chamid teeth
to the immature condition is the problem of the similarity of dentition of attached
or free valves, whether they are right or left. Odhner (1919) accurately stated that
current inversion theory “gives no satisfactory explanation of the process by which
a right valve may acquire the characteristics of a left one. ...”

The adult chamid hinge consists of a thick parivincular ligament sunk in a
deep pit that may appear as an obtuse escutcheon on the free valve. Three distinct
layers are present, consisting of an inner fibrous region covered with a partially
calcified lamellar layer and a thin outer periostracal layer. The ligament is attached
to substantial nymphs, whose lower margins are much thickened and reflected to
envelop part of the ligament. The ligament is invariably more deeply inserted into
the attached valve, and the nymphal margins of this valve are more developed
than in the free counterpart. The ventral edge of the nymphal margin is crenulated
and forms one side of the socket. It has been considered a tooth, and attempts have
been made to homologize it with one of the juvenile cardinals. A schematic cross-
section of the adult hinge showing the ligament and nymphal ridges is presented
in figure 2.

The extensive Allan Hancock Foundation collections from the central eastern
Pacific contain over 80 dissoconch and very recently settled chamids of several
species. By careful comparison it was possible to assemble probable developmental
stages of Pseudochama and Chama. Camera-lucida drawings are presented in fig-
ure 3 of P. corrugata Broderip and Chama cf. C. pellucida (Broderip).

In this material the very early dissoconch stages display two subumbonal cardi-
nals and a smaller posterior lateral in each valve. During development only the
lateral maintains its identity, or at least is a direct precursor of the adult structure.
The three heterodont teeth remain distinct until cementation and the period of rapid
idiomorphic growth. The pit between the cardinals of the free valve deepens and
the teeth become buried by a general thickening of the pit edges; the ventral margin

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receives most deposition and ultimately forms the lateral peg of the free valve. The
nymphal thickened margin originates as a group of tubercles that interdigitates with
the accretionary mass of the posterior lateral of the free valve.

It is evident that juvenile dentition is identical in arrangement in left and right
valve cemented chamids, so that no dental inversion occurs. Probably mechanical
constraints, due to the more rapid coiling growth of the attached valve supporting
an opercular free valve, lead to the development of a central socket in the attached
valve, accommodating a single lateral tooth in its opposite number. This interpreta-
tion is essentially a development of Odhner’s (1919) suggestion that similarity of
arrangement of hinge elements is the result of growth characteristics, but he did

Figure 2. Schematic cross section of adult hinge of Chama, showing ligamental insertion and
nymphal ridges. 1. = ligament; l.v. = left valve; r.v. = right valve.

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Figure 3. Schematic illustration of postulated hinge development in Pseudochama and Chama, prepared from camera-lucida drawings.

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not recognize the basic identity of the juvenile dentition and proposed a diverse
origin for the adult teeth of both groups, which he placed in separate genera.

The concept of separation of adult chamid hinge structures from the juvenile
condition is strengthened by the fact that the majority of cemented bivalves are
edentulous. Such structures as the sockets of Spondylus and the interlocking
mechanisms of Plicatula and Dimya are secondary developments, as well as the
loss of classical heterodont dental structures by the adult in Anodonta and the Thy-
asiridae. In these situations the early shell form may provide interesting phylo-
genetic insights, but the actual systematic placement is based upon adult morphology.
Postponed assumption of adult characteristics does not influence generic place-
ment, and it is on this basis that the cemented xenomorphic genus Hinnites is sepa-
rated from Chlamys, though the juveniles are indistinguishable.

Shell Growth and Form

Bivalve growth being accretionary, the shape of the generating curve is main-
tained. Shell formation, as Stasek (1963) phrases it, “. . . embodies a functional
continuum of past and present.” In the majority of bivalves the beaks are the point
of origin and geometrical locus from which growth radiates. In chamids, the beaks
are the point of origin, but their relative position changes, and finally, the growth
origin is transferred to the commissural plane. The continuous secretory mantle bor-
der results in the dental elements not remaining marginal, a tendency carried to
its extreme in the extinct rudists where the teeth of the free valve are placed sub-
centrally on the opercular disc.

Chamid growth form includes a pronounced tangential growth component
(Yonge 1967). Observation of long developmental series confirms that one-half
to three-quarter coiling of the shell occurs rapidly, but this growth pattern con-
tinues for a brief time only, and small specimens (3-5 mm) have attained the mature
configuration. Subsequent growth is a simple increase in size. Coiling growth also
occurs in a number of non-chamid taxa but the shell is usually equivalve, perhaps
the earliest example being the Ordovician Redonia Rouault, assigned by Chavan
(1966) to the carditaceans. The living Isocardia is also coiled (Owen 1953), as
are some representatives of the Anomalodesmata, notably Pecchiola, which was
originally considered to be a chamid. However, an elongate spiral design is incom-
patible with bivalve organization, which requires a large functioning pallial cavity
to house the water pumping and food collecting ctenidial apparatus. The majority
of bivalves maintain a constant ratio between ctenidial area and body size, how-
ever this is not true of spiriform taxa and those with a large subumbonal cavity.
Large, old, chamids may nearly halve the proportion of ctenidium to body and
there is no doubt this must have profound physiological implications. This prob-
lem was not encountered by the rudists, where the large attached valve was filled
with porous calcitic deposits, effectively maintaining a proportionately constant
shell cavity. Rudists developed further aids to maintaining adequate flow through
the pallial cavity, which included perforated upper valves and siphonal notches
(Vogel 1960).

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Systematic Position and Relationships

The many common morphological characters and the ontogeny of the three
living chamid genera are suggestive of a single phylogeny. While chamids have
long been accepted as a homogenous group, their placement in the Class Bivalvia
has been unsure. A marked similarity to the extinct rudists led support for their
incorporation within the Hippuritacea (Odhner 1919, Newell 1965, Yonge 1967).
Chamids have been thought to have descended from Silurian pachydonts which
became cemented to the substrate by one valve in the manner of Diceras (Descha-
seaux 1952). It is unlikely that the highly evolved porous- shelled Diceratidae could
be ancestral to the modern Chamidae.

Rudists are considered to be heterodonts, primarily on dental homology, as
no dissoconch stages have been identified from Mesozoic strata. Taylor and Ken-
nedy (1969) and Taylor et al. (1969) confirmed earlier reports that though hetero-
donts are aragonitic in shell structure, C. pellucida Broderip and P. exogyra
(Conrad) possess a superimposed external calcitic layer, a character shared with
rudists. However, this cannot be considered conclusive evidence for affinity (New-
ell 1965, Yonge 1967). The general similarities to the Hippuritacea are probably
the product of convergence as chamids occupied approximately the geographical
range of rudists and appropriated the ecological niche vacated by their extinction.

Other authors have traced chamid descent from the Carditacea (Dali 1903b);
the Crassatellacea (Bohm 1891); the Lucinacea (Nicol 1952a); and the Veneracea
(Fischer 1886). Kennedy et al.(1970), in a wide survey of the shell structure and
dental morphology of many fossil and living chamids discussed all these sugges-
tions and demonstrated a most probable relationship to the byssate Carditacea.

Chamids have a comparatively short geological history, the earliest undoubted
representatives occur in the Upper Cretaceous of Europe, and bear a strong resem-
blance to C. pellucida Broderip. A period of radiative expansion followed in the
Eocene, together with the development of diverse ornamentation. Chamidae are
abundant components of the tropical and subtropical shallow water faunules from
the Pliocene. The genera Chama and Pseudochama are widely distributed, but
Arcinella, which appeared in the Lower Miocene of Florida is endemic to Pacific
and Atlantic central America.

Eastern Pacific Chamidae

The roughly north-south axis of the American west coast cutting' across tem-
perate and tropical waters yields a rich and diverse chamid faunule. The great major-
ity of species were collected by Hugh Cuming and described by Broderip (1835a)
with a few additions by Reeve (1847). Unfortunately the descriptions are overly
short and type localities not clear. One problem results from the citation “Lord
Hood’s Island,” which may be either South Pacific or West American. Cuming
visited Polynesia in 1827-33 and collected at Lord Hood’s Island, now known as
South Marutea. The following years Cuming journeyed on the west coast of America
collecting at the Pearl Islands, Panama and the Galapagos group, of which the
southernmost island was originally Lord Hood’s Island, now known as Hood or

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Espanola Island. That Cuming in fact collected here is evidenced by Broderip
and Sowerby (1832) in their description of Stilifer astericola with a type locality
cited as “ad Insulas Galapagos (Lord Hood’s Island).’’ The chamid species with
doubtful type localities are C. pacifica, C. imbricata, and C. spinosa. I had occa-
sion to examine the types and compare them to materials of known distribution
and concluded that C. pacifica is a well established Indo-Pacific species, the cen-
ter of distribution being the Solomon archipelago. Broderip states the species is
identical to material of Samuel Stutchbury (1797-1859) who collected widely in
Australia and Polynesia. A similar situation exists for C. imbricata; the type is
identical to recently collected Indo-Pacific material and Broderip also mentions
Stutchbury materials; however, Broderip also reports a variety of C. imbricata,
citing the type locality as Insulas Galapagos. This specimen was separated by Reeve
(1847) and described under the name P. janus. This species is well established in
the Galapagos group and bears little resemblance to Broderip’s C. imbricata.
C. spinosa is distinguished by the uniform distribution of sparse spines and scales
upon the free valve and resembles nothing in the eastern Pacific province, and is
probably Indo-Pacific in origin. The western American chamid fauna appears to
be endemic with little relationships to Indo-Pacific representatives, and despite
free exchange until the end of the Miocene across the isthmus of Panama no west-
ern representatives extend into the Antillean region. The explanation may lie in
the almost total extinction in the Pacific of the coral reef biotope.

In this review of eastern Pacific species, literature citations are furnished only
to readily available works that are a help to identification. Because of many mis-
identifications and confusion, particularly in earlier works, published distribu-
tion data are to be viewed with reserve; those cited here have been verified with
material. The terminology of higher taxa is taken from “Treatise on Invertebrate
Paleontology’’ (R. C. Moore, ed. 1969).

Abbreviations for collections mentioned in the text are identified below:

AHF Alan Hancock Foundation, University of Southern California

ANSP Academy of Natural Sciences, Philadelphia

BM(NH) British Museum (Natural History), London

CAS California Academy of Sciences, San Francisco

LACM Natural History Museum of Los Angeles County

MNHN Museum National D’Histoire Naturelle de Paris

MCZ Museum of Comparative Zoology, Harvard

SDSNH San Diego Society of Natural History

USNM National Museum of Natural History, Washington, D.C.

SYSTEMATIC REVIEW
SUPERFAMILY CHAMACEA LAMARCK 1809

Shell cemented, at least temporarily, to substrate. Umbones prosogyrate, liga-
ment parivincular, adult dentition consisting of a large lateral process in the upper
valve inserted in a deep pit on opposite valve. Sculpture generally well developed,
consisting of spines sometimes conjoined into concentric frills. Pallial line entire,
adductor muscle scars subequal. Upper Cretaceous to Recent.

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FAMILY CHAMIDAE LAMARCK 1809

Shell characters as in Superfamily. Variable and xenomorphic. Predominantly
among shallow warm water epifauna. The shell may be ponderously thickened in
old specimens and external characters frequently obliterated by abrasion and the
activity of shell borers. Anatomically this family is conservative. Mantle exten-
sively fused except for a small pedal gape and two small delicate siphons formed
solely from the inner mantle fold. Adductor muscles elongate, nearly subequal.
Foot reduced, laterally compressed. Ctenidium comprising a large inner demibranch
with a much smaller outer demibranch. Lamellae plicate, synaptorhabdic, fila-
ments connected by substantial interfilamental junction. Interlamellar junctions
short and numerous. Labial palp small, generally asymmetrical, with 12-20 palpar
ridges. Mouth small, leading to short, longitudinally plicated oesophagus. Stomach
large, divided by prominent ventral ridge. Style pouch and midgut conjointed.
Intestine short, piercing heart ventricle.

The anatomical characteristic of the Chamidae suggests that they are adapted
to waters with little suspended materials. The alimentary system is modified for
the acception of fine particulate materials. Representatives of the family occur on
hard substrates removed from zones of sedimentation. Geologically this group is
probably indicative of warm water as those few representatives extending to cooler
waters are all small and lack pronounced sculptural processes.

There are three West American genera.

Generic Key to the West American Chamidae

1. Shell nearly equivalve, lunule pronounced; not attached
Shell inequivalve, no lunule; cemented

2. Shell attached by left valve, nepionic shell small
Shell attached by right valve, nepionic shell large

GENUS CHAM A LINNE 1758
Type (subsequent designation: Schmidt 1818) Chama lazarus Linne 1758

Shell thick, porcellaneous, sometimes with waxy translucent outer layer. Shell
cemented by left valve. External surface smooth or ornamented with irregularly
placed concentric and radial processes. Attached valve with hyote-type spines.
Commissural margin sometimes produced. Dentition consisting of a single broad
tooth-like process in the right valve, fitting into socket in left valve. Nepionic shell
small, with typical heterodont dentition, externally ornamented with concentric
and radial sculpture. No abrupt transition of growth pattern at the post-neanic stage.
Anatomy as for Superfamily.

Subgenera proposed in Chama, such as Cipliacella Vincent, 1928 (Type C.
pulchra Ravn 1902) or Psilopus Poli 1795 (Type C. gryphoides Linne 1758) are
based upon minor variations not significant above the species level.

Twelve species occur in the eastern Pacific, the majority in the Panamic
province.

Arcinella

2

Chama

Pseudochama

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No. 278

Artificial Key to West American Chama

1 . Interior shell not colored 2

Interior of shell colored 8

2. Both valves strongly arched, attachment area small 3

Upper valve flat, attachment area large 4

3. Exterior ornamented with many short narrow spines C. corallina

Exterior ornamented with few long broad arched spines C. sordida

4. Exterior ornamented, no distinct color pattern . 5

Exterior smooth, with uniform brown lines C. venosa

5. Shell waxy, with wide, minutely crenulated commissural shelf 6

Shell porcellaneous with narrow, coarsely crenulated commissural shelf 7

6. Shell laterally elongated, exterior with short uniform frills, fused into concentric

wrinkles C. pellucida

Shell vertically elongated or round, exterior with irregular thin frills, not fused into con-
centric wrinkles C. arcana

7. Exterior white spines uniform, fusing into concentric frills C. squamuligera

Exterior colored, spines irregular, separate C. garthi

8. Internal color limited to narrow marginal band 9

Internal color diffused 10

9. External sculpture lacking or of narrow spines C. buddiana

External sculpture of broad, striated foliations C . frondosa

10. Internal color a diffuse marginal flush, or on anterior adductor muscle scar . .C. mexicana

Internal color extensive 11

11. Interior purple, hinge teeth bright coral red C. echinata

Interior yellowish red, hinge teeth white C. tinctoria

Chama arcana new species
Figures 4 a, b

Chama pellucida auctt., not Broderip 1835a: 149; Keep 1888:182, fig. 155 (as of Sowerby);

Arnold 1903:130 (Pliocene, Pleistocene of California); Arnold 1910:38 (Upper Miocene

of California); Grant and Gale 1931:279; Soot-Ryen 1931:314 (Galapagos Islands);

Smith and Gordon 1948:173.

Diagnosis: The new species can only be confused with C. pellucida Broderip,
but the commissural shelf is wider and the latter lacks the streaks of bright color often
present on the upper valve. The sculpture of C. arcana is irregular, thin, and period-
ically drawn out into longitudinally striated lamellae, which are not present in C.
pellucida , where the sculpture is more uniform and subdued. The shell of C. pellu-
cida is proportionately thicker and tends to be anteroposteriorly elongated, while in
C. arcana it is subcircular or dorsoventrally elongated. A distinct, but small, pal-
lial sinus is present just below the adductor muscle in C. pellucida, which is absent
in the new species.

Description: Shell interior porcellaneous, white, exterior waxy translucent.
Outline variable, depending upon habitat, either round or dorsoventrally elongated.
Cemented to substrate by wide area of left valve. Exterior sculpture often abraded
and encrusted, color white, sometimes with streaks of pink or red particularly on
posterior of right valve. Sculpture of either valve consisting of close-set foliations
irregularly joined into thin translucent concentric lamellae, with several radial rows

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15

of larger prolongations. Ligament deeply sunk and placed on a substantial nymph.
Dental processes not highly developed, nymphal ridge of left valve with a strongly
developed longitudinal groove. Shell margins minutely denticulated. Commissural
shelf broad, lacking inner layer, sometimes iridescent. Adductor muscle scars
large. Pallial lines shallow, entire.

Holotype measurement: Length 55, height 64, width 39 mm.

Type locality: Newport Bay, California (33°37'N, 117°55'W). Intertidal
— Collected March 1965 by J. McLean.

Holotype deposition : LACM 1723.

Geographic range: Yaquina Point, Oregon (44°N) to San Juanico Bay, west
coast of Baja California (26°N).

Bathymetric range: In Oregon and California this species occurs from the low
intertidal level down to 50 meters. In its southern range it is always subtidal, down to
80 meters.

Habitat: Clear water, often in nooks and crannies in exposed zones. Attached
to a solid substrate, rocks, pilings, breakwaters, subtidally often attached to gravel.

Etymology: The specific name is derived from the Latin adjective arcanus
(secret), referring to the long hidden distinctness of this species from C. pellucida.

Discussion: This species is common in the California Province, first appearing
in the Upper Miocene (Arnold 1910) and more frequently in the Pliocene and Pleisto-
cene (Arnold 1903). It occurs higher in the intertidal zone than other chamids and
is frequently found on pilings and other man-made objects. It has the most northern
range of the genus, and, in common with some other cool water bivalves, extends
down the coast of Baja California. Dali (1921) included the Galapagos Islands; this
is probably not correct as USNM does not contain specimens from Galapagos.
Soot-Ryen (1931) also recorded this species from the Galapagos group. C. arcana
is entirely absent from the tropical Panamic province and its congener C. pellucida
Broderip appears in similarly cool southern waters. These two species are closely
related, but consistent differences in sculpture and shell shape separate them as
discussed above.

Of the West American chamas, C. arcana and C. pellucida occupy the cool-
est waters. Lowenstam (1954) first noted the presence of an outer calcitic layer in
C. pellucida and later suggested (Lowenstam 1963) that the aragonitic outer layer
of warm water chamids is transformed to prismatic calcitic structure in a cool water
environment. Taylor and Kennedy (1969) confirmed the calcitic external layer,
but showed it to be an extra layer superimposed upon the normal aragonite shell
of the Superfamily. This fact, coupled by their belief that C. pellucida is distributed
transequatorially led Taylor and Kennedy to reject Lowenstam’s hypothesis. In
an appendix Taylor and Kennedy (1969) noted a calcitic layer in Pseudochama
exogyra and suggested that this species is conspecific to C. pellucida. I cannot
agree with these authors that the occurrence of a calcitic outer layer in these three
species is sufficient grounds for combining them into a single taxon. It is well estab-
lished that warm water bivalves tend to display a higher proportion of aragonite
than cold water representatives, and Lowenstam’s suggestion should be recon-
sidered, not on an individual ecomorphic basis but in a phylogenetic sense.

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Chama buddiana C. B. Adams 1852
Figures 5 d, e

Chama buddiana C. B. Adams 1852:253 (Type locality: Panama Bay, 7°N. Syntypes MCZ);

Turner 1956:36, pi. 20, figs. 7, 8 (designation of lectotype MCZ 190150); Olsson

1961:224, pi. 34, figs. 2-2c; Emerson and Hertlein 1964:348 (Pleistocene of Mexico);

Keen 1971:147, fig. 346.

External surfaces pink to deep red, ornamented with irregular radial rows of
small triangular white spines. Interior white with pinkish red marginal band. Shell
margin finely crenate.

Discussion: The exterior coloration, the contrasting small triangular white spines
interspersed with a few large ones in irregular rows, together with the marginal band
of color distinguish this species.

This is the largest and most abundant chamid occurring off Panama but it is
uncommon elsewhere. The Port Parker location, from the Allan Hancock Stations
is a northward extension of the confirmed range. Dali’s (1921) record of this species
from California is certainly in error, probably stemming from the fact that Adams
also cited material collected by Lt. Green at Guaymas. It is clear that Adams in-
tended to describe those specimens personally collected at Panama but mentions
material he considered identical.

Carpenter (1864) placed his C. frondosa fornicata in the synonymy of this
species. After examining the types I consider that these species are in fact not
synonymous, and that Carpenter’s material is referable to C. mexicana Carpenter,
1857. Chama rubropicta Bartsch and Rehder, 1939 is an immature C. buddiana
Adams, 1852.

C. buddiana is found in the low intertidal zone to 2 meters, generally attached
to rock on large boulders. It ranges from Port Parker, Costa Rica (11°N) to Cape
San Francisco, Ecuador (0°39'N). Also reported from Clipperton Island and the
Galapagos Group (Albermarle, Narborough, and Indefatigable Islands). Emerson
and Hertlein (1964) recorded this species from the Mexican Pleistocene.

Chamma corallina Olsson 1971
Figures 6 c-f

Chama corallina Olsson, 1971:39, figs. 7-10. (Type locality: Off Punta Escondido, Gulf of
Panama, 7°59'N, 78°30'W, in 55 meters. Holotype USNM 701157); Keen 1971:197,
fig. 346a.

Shell with both valves inflated, attachment area small. Exterior pinkish brown
to red. Interior white. Surface sculpture of fine radial riblets with irregular sharp
spines. Shell margin crenulated.

Discussion: The small size, rotundity of outline and concentric wrinkles with
small sharp spines readily distinguish this rare species. Mr. and Mrs. E. E. Wahren-
brock collected several specimens from trash fish dumps in Mazatlan that had been
trawled off the Sonora coast of Mexico.

1976

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17

This species is most frequently attached to small pebbles or calcareous poly-
chaete tubes in 18 to 95 meters. It ranges from the Sonoran coast of Mexico (23°N)
to Punta Escondido, Gulf of Panama (7°59').

Chama echinata Broderip 1835
Figures 7 a-f

Chama echinata Broderip 1835a: 150 (Type locality: Puerto Portrero, Bay of Guayaquil,
Ecuador, 2°11'S. Syntypes BM(NH) 1950. 11.1.20-22); Broderip 1835b:305, pi. 39,
fig. 5; Reeve 1847: pi. 7, fig. 35; Stearns 1893:375; Clessin 1889:14, pi. 6, fig. 2;
Keen 1971:147, fig. 347.

Chama coralloides Reeve 1847: pi. 4, sp. 18 (Type locality: Puerto Portrero, Ecuador,
2°1TS. Holotype BM(NH) no. number).

Chama delesserti Chenu 1846: pi. 6, fig. 4 (Type locality: Puerto Portrero, Bay of Guayaquil,
Ecuador, 2°11'S. Holotype BM(NH) 1950.11.1.20).

Exterior yellowish white, sculpture of many short irregular spines, often totally
abraded in mature specimens. Interior deep purple, hinge teeth bright coral red.
Juvenile specimens display only the purple interior, the red hinge appearing later.

Discussion: Reeve (1847) illustrated C. echinata but separated two worn speci-
mens of Broderip’s type series to erect C. coralloides. Chenu (1846) reproduced
Broderip’ s (1835b) figure of C. echinata under the new name C. delesserti. Carpen-
ter (1857a) pointed out this confusion and correctly surmised that Chenu’s species
should also be placed in synonymy.

T^ie deep purple of the interior, contrasting with the bright coral hue of the hinge
teeth distinguishes this species from all other American chamids. The outside of
the shell is frequently abraded and overgrown, attached to large rocks from the low
intertidal zone to 25 meters. The geographical range is from Angel de la Guarda
Island, Gulf of California (29°N) to Huanape Island, Northern Peru (8°34'S).

Chama frondosa Broderip 1835
Figures 8 a-c

Chama frondosa Broderip 1835a: 148 (Type locality: Isla La Plata, Ecuador, 1°18'S, BM(NH)
1950.11.1.55); Broderip 1835b:302, pi. 38, fig. 1; Reeve 1847: pi. 1, fig. la; Stearns
1893:375; Lamy 1927:314; Durham 1950:73, pi. 17, figs. 5, 6 (Pliocene to Recent of
Mexico); Emerson 1960:6 (Shell middens of Mexico); Olsson 1961:225, pi. 34, figs, la,
b, pi. 86, fig. 2; Keen, 1971:147, fig. 348.

Chama pacifica Carpenter (Gould MS) 1847, not Broderip 1834 (fide Carpenter 1857b).

Chama parasitica Rocheburne 1895:243 (Type locality: San Jose Island, Gulf of California,
Mexico, 25°N. Holotype MNHN).

Shell heavy, pinkish white, external sculpture of wide radially striated folia-
tions. Interior white, with narrow pink or purple marginal band.

Discussion: This infrequently encountered chamid is the only West American
species with foliated spines. It occurs cemented to rocks and large boulders, extend-
ing from the subtidal zone to 25 meters. The geographic range is from southern part

Contributions in Science

No. 278

of the Gulf of California at La Paz (24°30'N) to Salango Bay, Ecuador (1°35'N). I
have not seen genuine material from the Galapagos Islands and records from the
outer coast of Baja California and California are certainly misidentifications. This
is a warm water species and there is some doubt as to its northern extent, as the La
Paz record is based upon a single specimen.

Chama garthi new species
Figures 9 a, b

Chama spinosa auctt., not Broderip 1835; Carpenter 1857a:90; Strong and Hanna 1930:15.

Diagnosis: The species may be confused with C. squamuligera Pilsbry and
Lowe, but is easily distinguished by the bright external coloration and by the spines,
which never fuse into crenulated frills.

Description : Shell small, rounded, exterior irregularly mottled with purplish red.
Attachment area small. Left valve deeply cupped, right valve nearly flat. Right valve
covered with dense radial rows of short imbricated free spines; left valve with
fewer wider spines. Interior white or stained light brown; margins delicately
crenulated.

Holotype measurement: Length 19.5, height 23.7, width 15 mm.

Type locality: Octavia Bay, Colombia (6°50'N, 77°41'10"W). Shallow water.
Allan Hancock Station 435-35, January 28, 1935.

Type deposition: AHF 167 (Holotype). AHF 168 (Paratype).

Geographic range: Type locality and Salango Island, Ecuador (1°35'S).

Bathymetric range: Intertidal level to 22 meters.

Habitat: Rock and coral.

Etymology: The species is named for John S. Garth of the Allan Hancock
Foundation in small recognition for his inestimable services to Central American
malacology while accompanying all the Hancock Pacific Expeditions Velero III
cruises (1931-1941).

Discussion: The external coloration and delicate imbricated spines make C.
garthi the most elegant of West American chamids. There is a superficial similarity
to juvenile C. echinata Broderip, but the new species displays a wide commissural
shelf, entirely lacking in young C. echinata and the attached valve of C. garthi
carries a few wide spines, rather than the many small spines of C. echinata.

Chama maculata Clessin 1889
Chama maculata Clessin 1889:43, pi. 4, figs. 4, 6.

The brief description and indistinguishable illustration relegate this species to
a nomen dubium status. The type locality is the Strait of Magellan. It is highly
improbable that these cold waters support any representative of the Chamidae.
The literature yields no other mention of a chamid occurring south of approximately
33°S. Unfortunately the Clessin collection, housed in the Stuttgart Museum, was
totally destroyed during the Second World War.

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19

Chama mexicana Carpenter 1857
Figures 10 a-c

Chama frondosa mexicana Carpenter 1857a: 87 (Type locality: Mazatlan, Mexico, 23°N.
Syntypes BM(NH) Carpenter Collection Tablets 425-438); Hertlein and Strong 1955:114
(Galapagos Islands); Hertlein and Emerson 1956:165 (Pleistocene of Mexico); Keen
1971:147, fig. 349 (as C. mexicana).

Chama frondosa fornicata Carpenter 1857a:89 (Type locality: Mazatlan, Mexico, 23°N,
Syntypes BM(NH) Carpenter Collection Tablets 439-443); Keen 1968:397, pi. 56,
figs. 31 a, b, figs. 35 a, b.

Chama frondosa ( var (3) Broderip 1835a: 149 (Type locality: Mazatlan, Mexico, 23°N. Type
not located in BM(NH); Broderip 1835b:302, pi. 38, fig. 2.

Chama producta Broderip 1835a: 150 (Type locality: Gulf of Tehuantepec, Mexico, 16°N.
Holotype BM(NH) 1950.1.1.60); Broderip 1835b:305, pi. 39, fig. 4: Reeve 1847,
pi. 3, fig. 13; Clessin 1889:20, pi. 10, fig. 1: Lamy 1927:314; Keen 1971:899 (Nomen
oblitum).

Chama purpurascens Tryon (Conrad MS) 1872:117 (as synonym of C. frondosa Broderip
1835); Pilsbry and Vanatta 1902:551 (Galapagos Islands, as Chama frondosa purpura-
scens Conrad).

Chama compacta Clessin 1889:25, pi. 10, fig. 4 (Type locality: unknown. Type destroyed
in WW. H).

Shell exterior pink to deep red, with many small, and two radial rows of larger
spines. Interior white to yellowish. There is an indistinct flush of pinkish purple
around the anterior adductor muscle scar and part of the shell margins. Gerontic
specimens generally riddled by borers and with spines abraded.

Discussion: This species is readily separable from other West American chamids
by the irregular internal purple red flush, which generally spreads to include the ante-
rior adductor muscle scar.

There is some confusion in the literature concerning the type locality of C.
mexicana. Carpenter (1857a) recognized that his specimens were identical to
Broderip’ s C. frondosa var (3, and intended merely to apply an acceptable name to
it. In such a situation, Broderip’s specimen must remain the type, unless a case
can be made to suppress it entirely. Such a case can be made on the basis that sym-
bols have no nomenclatural status or that Broderip’s taxon may be considered a
species inquirenda. The extreme brevity of Broderip’s description would also favor
considering it a nomen dubium. I was unable to locate C. frondosa var (3 in the
Cuming Collection, and incline to accept Carpenter’s material as syntypic, or at
least plesiotypic.

Comparison of the paratype of C. producta Broderip (Fig. 10a) to the types
of C. frondosa mexicana and C. frondosa fornicata convinced me they are syn-
onymous and well removed from C. frondosa Broderip. However, Reeve (1847)
thought C. producta to be identical to C. iostoma Conrad 1837, a species indigenous
to Hawaii (Dali et al. 1938). Keen (1971) did not accept this view, and rejected
C. producta on the basis of discrepancies in the description. Under guidelines
adopted by the 1972 ICZN Commission meeting in Monaco the name is not avail-
able for nomenclatural purposes. In the unlikely event that it is proven desirable
to reinstate C. producta Broderip, formal petition will have to be made to ICZN.

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The species occurs on small cobbles and boulders, nearly always on a sandy
substrate, from the middle intertidal zone to 80 meters. The geographical range
is the head of the Gulf of California, Mexico (31°N) to San Jose point, Guatemala
(13°46'N).

Chama pellucida Broderip 1835
Figure 4 c, d

Chama pellucida Broderip 1835a: 149 (Type locality: Iquique, Chile, 20°13'S, in 17-20 meters.
Syntypes BM(NH) 1950.11.1.63-65); Broderip 1835b:302, pi. 38, fig. 3; Reeve 1847:
pi. 6, fig. 32: Clessin 1889:18, pi. 8, figs. 3-4; Lamy 1927:345; Olsson 1961:225,
pi. 33, figs. 2, 2a, pi. 34, fig. 5; Marincovich 1973:11, fig. 10; not Smith and Gordon
1948:173; part Osorio and Bahamonde 1970:198 (Juan Fernandez Islands); not Hertlein
and Grant 1972:227, pi. 43, figs. 12, 15.

Chama chilensis Philippi 1887:173, pi. 37, fig. 9 (Type locality: Pliocene of Laguna de Cahuil,
Chile, 34°30'S, 72°01'W. Holotype MNHN no number).

Shell rounded, generally longitudinally elongated. Sculpture of short, trans-
lucent fluted spines, fused into concentric ridges. Exterior white or pink, sometimes
dashed with red. Interior white, margins sharply crenulated. Commissural shelf
wide. Small pallial sinus present.

Discussion: This species is close to the northern C. arcana new species, and
possibly bears the same relationship to it as do Caribbean congeners of central eastern
Pacific species. Both C. arcana and this species are inhabitants of cool waters,
effectively separated by the warm equatorial zone since Miocene times. The more
elongate form, proportionately thicker shell, and short concentric spines fused into
ridges differentiate this species from its northern relative.

It appears that Keep (1888) first confused northern representatives with C.
pellucida which is restricted to the Peruvian province and does not occur north of
Paita. Chama chilensis Philippi from the Pliocene of Chile is certainly this species.
Californian fossil materials, some as early as Late Miocene are all referable to C.
arcana new species. Odhner’s (1922) reference to C. imbricata Broderip, from the
Juan Fernandez Islands, is actually to C. pellucida.

This species occurs high in the intertidal zone to 30 meters, most frequently
nestling in fissures of rocks, or on pilings. The range is from Paita, Peru (5°15'S), to
Tocopilla, Chile (22°S). It is also abundant in the low intertidal zone of the Juan
Fernandez Islands (33°S).

Chama sordida Broderip 1835
Figures 6 a, b

Chama sordida Broderip 1835a: 151 (Type locality: Isle of Cuna, Central America. Syntypes
BM(NH) 1950.11.1.52-53); Broderip 1835b:306, pi. 39, figs. 8, 9; Keen 1971:149,
fig. 35 (Right figure only).

Exterior reddish brown, the overall pattern of small radial riblets sparsely
interspersed with large imbricated spines. The interior white, with the exterior
color showing through. The margin is finely crenulated.

1976

Eastern Pacific Chamidae

21

Discussion: The radial ribs and few large spines make it unlikely to confuse the
identity of this elegant species. This is not C. digueti Rochebrune as suggested
by a number of workers, which has an entirely different sculpture and should be
assigned to C. venosa Reeve.

This species is generally attached to calcareous organisms and occurs from
the subtidal zone to 45 meters. The geographic range is from Angel de la Guarda
Island, Gulf of California, Mexico (29°39'N), to Gorgona Island, Colombia (3°01'N).

I have been unable to trace the original type location, given as Isla Cuna,
America Centrali. The latter was in contemporaneous use for the region north of
Panama Bay, approximately 9°N to 15°N. Isla Punta Icaco, Nicaragua (12°33'N,
87°16'W) is here designated the type locality.

Chama squamuligera Pilsbry and Lowe 1932
Figures 9 c, d

Chama spinosa auctt., not Broderip 1835a (in part).

Chama squamuligera Pilsbry and Lowe 1932:103, pi. 14, fig. 10 (Type locality; San Juan
del Sur, Nicaragua, 11°15'N, 85°53'W. Holotype ANSP 155623, Paratypes SDSNH
475a, b); Durham 1950:73, pi. 17, fig. 3, 6 (Pliocene to Recent of Mexico); Hertlein
and Allison 1966:139 (Clipperton Island 10°17'N, 109°13'W); Keen 1971:149, fig. 351.
Chama rubropicta Bartsch and Rehder 1939:13, pi. 3, figs. 6-10 (Type locality: Clipperton
Island, 10°17'N, 109°13'W. Holotype USNM 472553)

Chama squamuligera rubropicta Bartsch and Rehder. Hertlein and Emerson 1953:350 (Clip-
perton Island); Salvat and Ehrhardt 1970:227 (Clipperton Island).

Shell small, pure white to yellowish. Exterior sculpture of thin broadly im-
bricated spines conjoined into concentric frills. In worn specimens the frills are
reduced to concentric wrinkles. Interior white, margin finely crenulated. Commis-
sural shelf wide, often granulose.

Discussion: This small nearly colorless species is characterized by the many
spines, tending to fuse into irregular concentric lamellae.

When proposing this species Pilsbry and Lowe considered it very similar to
C. spinosa Broderip (Fig. 9e), separating it on a purely geographical basis. C.
spinosa has been listed in the West America fauna (Strong and Hanna 1930)
— another legacy from the Cuming location “Lord Hood’s Island,” in fact South
Marutea, as Broderip’ s species is clearly identifiable with South Pacific material
and probably synonymous to C. asperella Lamarck 1835, which has a few months’
priority. It is probable that C. flavida Clessin 1889 described from Panama with
no suggestion whether Pacific or Caribbean will prove to be this species. Clessin ’s
description and illustration do not match Caribbean materials I have examined;
they do, however, conform to the yellowish phase of C. squamuligera. Should
they prove synonymous Clessin’ s name will have priority, unless a case for treating
it is as a nomen oblitum can be made.

This species is frequently found nestling in dead bivalve shells, or on small
pebbles from the subtidal zone to 20 meters. It ranges from Gonzaga Bay, Gulf
of California, Mexico (29°47'N), to Bahia Honda, Panama (7°43'N), also in the
Galapagos Group (Indefatigable and Barrington Islands) and Clipperton Island.

22

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Chama tinctoria new species
Figures 5 a-c

Chama pacifica auctt., not Broderip 1835 (Holotype BM(NH) 1950. 11.1.54, Indo-Pacific);

Tryon 1872:119; Clessin 1889:15, pi. 7, fig. 2. Not chama pacifica Carpenter (Gould

MS) 1857b (synonym of Chama frondosa Broderip 1835).

Chama broderipi auctt., not Reeve 1847 (Holotype BM(NH) 1952.4.9.1, Indo-Pacific);

Tryon 1872:119; Lamy 1927:319 (as Chama pacifica broderipi Reeve 1847).

Diagnosis: This variable species can only be confused with C. buddiana Adams,
but is more brightly colored and bears more spines on the upper valve, while the lower
valve displays uniform radial costae never found on C. buddiana. Inside, the
new species is more highly colored, and, though C. buddiana may be lightly macu-
lated with pink or lilac, it never displays the bright rose brown. C. tinctoria has
no colored marginal band.

Description: Shell very inequilateral, exterior of right valve brightly colored,
with purple radial lines on anterior region, posterior white, central portions pink. Left
valve exterior uniform brownish red. Sculpture of right valve consisting of short
imbricated scales, white at the base and yellowish red at the tips. Left valve cov-
ered with shallow uniform radial costae, with sparse imbricated scales. Interior of
right valve white, with a purple to brown patch. Interior of left valve white, flushed
light brown to rose red with a darker border. Margin uniformly crenulated.

Holotype measurement: Length 32.5, height 37, width 29 mm.

Type locality: Bahia Honda, Panama, 7°43'16"N, 81°32'55"W, Allan Hancock
Foundation “Velero” Station 249-34, in 28-37 meters.

Type deposition: AHF 169 (Holotype). AHF 170 (Paratype).

Etymology: Named from the Latin adjective tinctorius — of dyeing, to draw
attention to the remarkable exterior and interior color combination.

Geographic range: Gulf of California (?). Tres Marias Isfands, Mexico
(21°26'N), to Bahia Honda, Panama (7°43'N).

Bathymetric range: 15 to 92 meters.

Habitat: Rocks and bivalve shells.

Discussion: Carpenter (1857b) cited “C. pacifica Gould” off the west coast of
America and synonymized it with his C. frondosa mexicana. I have been unable
to trace the specimen or any reference in Gould’s publication to C. pacifica and
consider it an MS name; however, it is possibly a lapsus for C. pacifica Broderip,
which has appeared with its synonymous C. broderipi Reeve in eastern Pacific
literature. Diguet in 1894 collected from the Gulf of California a large chamid he
identified with C. broderipi Reeve, 1847. Lamy (1927) reviewing the collections
in the Paris Museum cited Diguet’s material as C. pacifica broderipi Reeve and
accepted a pan-Pacific distribution. On examination of this specimen I concluded
it is a distinct species with only superficial resemblance to Indo-Pacific representa-
tives, and identical to two lots in the Allan Hancock Foundation collected off Mex-
ico and the Gulf of Panama. As Diguet’ s material lacks a specific type locality and
despite its large size, appears immature, I designate the Allan Hancock Foundation
Panamic specimen as the type.

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Eastern Pacific Chamidae

23

Chama venosa Reeve 1847
Figures 1 1 c-e

Chama venosa Reeve 1847: pi. 7, sp. 34 (Type locality: not stated. Syntypes BM(NH)
1950.11.1.4-6); Clessin 1889:36, pi. 16, fig. 6; Lamy 1927:341; Keen 1971:149, fig. 352.
Chama diqueti Rochebrune 1895:243 (Type locality: San Jose Island, Gulf of California,
Mexico, 25°N. Syntypes MNHN); Keen 1971:149, fig. 350 (as Chama sordida Broderip
1835, left and center figures only).

Shell exterior smooth, with a few short scattered spines, white with an elegant
pattern of fine reddish brown lines. Margins slightly and irregularly crenulated.

Discussion: This small species with parallel fine lines on the smooth shell cannot
be mistaken. Superficially it is close to P. janus Reeve, but in this species the elegant
fine lines are replaced by brown staining of the depths of radial striae and the upper
valve demonstrates two distinct sculpture patterns. Keen (1971) illustrated the holo-
type of C. digueti, synonymizing it with C. sordida Broderip. Her illustration is
one of three single specimens in the Paris Museum considered by Rochebrune when
proposing his new species, but the description is based upon a syntypic cluster of 4
specimens. Lamy (1927) states this group to be the type lot and I believe Rochebrune
drew attention to mutual fusion at the start of his description “Testa aggregata . .
as the cemented nature of chamids was well established by then. I follow Lamy
(1927) in considering C. digueti to be a junior synonym of C. venosa as it bears
the flattened upper shell valve and reddish brown lines of the latter species and
entirely lacks the bi-convex shape and long imbricated spines of C. sordida. A fine
specimen in the d’Orbigny collection from Paita, Peru (BM(NH) 1954. 12.4.820)
is undoubtedly this species.

This species has been collected on wharf pilings and dead shell from the sub-
tidal zone to 4 meters. Distribution is centered in the Gulf of California, Mexico
from 28°N and south possibly to Paita, Peru (5°S). Guaymas, Sonora, Mexico
(29°52'N, 1 11°06'W), is here designated the type locality.

GENUS ARC IN ELLA SCHUMACHER 1817
(= ECHINOCHAMA FISHER 1887)

Type (monotype) A. spinosa Schumacher 1817 = A. arcinella Linne 1767.

Shell nearly equivalve, briefly cemented by right valve during early growth.
Sculpture of radial rows of long, partially recurved spines, interspaces pitted, result-
ing in a reticulated appearance. Beaks prominent, prosogyrate. Lunule deeply
impressed. Ligament short, deeply buried. Hinge elements as in Chama but more
delicate. Nepionic shell distinctly demarcated, sculptured with concentric ridges.

Arcinella was first proposed by Oken (1815) for a carditid genus and is a
senior homonym of Arcinella Schumacher 1817. In 1956 (Opinion 417) the ICZN
rejected Oken as non-binomial, so Arcinella Oken no longer preoccupied Schu-
macher’s genus. However, Echinochama Fischer 1887 is a synonym of Arcinella
Schumacher; both cited Chama arcinella Linne 1767 as the type of the genus. Keen

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No. 278

(1962) summarized the situation, and pointed out that a rejected senior homonym
has no status unless subsequently validated. On the basis of strict priority she pro-
posed the use of Arcinella Schumacher. Nicol (1965) felt there may be some objec-
tion to adopting Arcinella and it could be considered a nomen oblitum. As no
application has been made to the ICZN to retain Echinochama Fisher, and Arci-
nella Schumacher has appeared several times in the literature since Keen’s 1962
article, it may be considered established in the taxonomy.

The gross external anatomy of Arcinella has already been discussed and ap-
pears very close to Pseudochama, except the foot is longer and the pedal aperture
rather more ventral. The nepionic shell is similar to Pseudochama as is the abrupt
post-neanic change in shell sculpture.

The taxon is confined to central America, appearing in the Early Miocene of
Florida (Nicol 1952a). Speciation and distribution has occurred in the Caribbean,
but the group is poorly developed on the Pacific side.

One eastern Pacific species:

Arcinella calif ornica (Dali 1903)

Figure 6 g

Echinochama californica Dali 1903a:950, pi. 62, fig. 5 (figure only); Dali 1903b: 1404, 1406.

(Type locality: Cedros Island, Baja California, Mexico, 28°N, in 24 meters. Holotype

USNM 96452); Keen, 1971:149, sp. 353 (as Arcinella californica).

Echinochama arcinella californica (Dali), Nicol 1952a:806, pi. 119, fig. 8; Olsson 1961:227,

pi. 34, fig. 3.

Shell equivalve, whitish yellow, anterior portion produced into a lobe, lunule
deep. Sculpture of symmetrical radial rows of long, sometimes recurved spines.
Interior white, border finely crenulated.

Discussion: This rare species is closely related to the Caribbean A. arcinella
(Linne 1767) but may be distinguished by the more produced anterior lobe, longer
spines and more distinct surface pattern. Nicol (1952a) considered western repre-
sentatives as only a subspecies of the Caribbean form and proposed a new subspecies
A. a. olssoni for Pliocene or Pleistocene Pacific Panama material displaying par-
ticularly large flat spines.

The type locality of A. californica cited by Dali is Cerros (now Cedros) Island,
situated on the outer coast of Baja California. Though Pilsbry and Lowe (1934)
refer to single specimens dredged off Mexico at Manzanillo (19°N) and Acapulco
(17°N) and the S.S. Berry collection contains several specimens from Angel de
la Guarda Island, Gulf of California (29°N), the main distribution appears to be
south of the Gulf of Tehuantepec (15°N). This species is represented in the Allan
Hancock Foundation holdings by several small valves from Port Utria, Colombia
(5°N). The geographic range is from Cedros Island, Mexico (28°N) to Port Utria,
Columbia (5°58'N). Juveniles are generally attached to calcareous organic struc-
tures, particularly gastropod shells. The adults lie free on the substrate in 25 to 77
meters.

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GENUS PSEUDOCHAMA ODHNER 1917

Type Chama cristella Lamarck 1819 (subsequent designation: J. Gardner 1926, see Nicol
(1952b)).

Shell attached by right valve. Nepionic shell large, subquadrate. Other char-
acters as of the family. Oligocene to Recent.

Seven eastern Pacific species:

Artificial Key to West American Pseudochama

1. Shell interior white, sometimes with brown patch 3

Shell interior extensively streaked or uniformly colored 2

2. Color streak rose or red P. clarionensis

Shell with extensive purple stain P. corrugata

3. Upper valve sculpture medially bisected P. janus

Upper valve sculpture not bisected 4

4. Shell inner margins smooth or finely crenated 5

Shell inner margins uniformly coarsely ridged P. saavedrai

5. Shell lacking obvious periostracum 6

Shell with thin brownish periostracum P. dalli

6. Sculpture of numerous concentric lamellae and spines P. exogyra

Sculpture of irregular fluted broad spines P. panamensis

Pseudochama clarionensis Willett 1938
Figures 12 e, f

Pseudochama clarionensis Willett 1938:48, pi. 4, figs. 1, 2 (Type locality: Off Clarion Island,
Mexico, 18°22'N. Holotype LACM 1058, Paratype LACM 1058a); Keen 1971:151, fig.
354.

Shell exterior bright red, with scattered white, short, imbricated spines. The
inner margin is delicately crenated. Interior white, clouded or streaked with bright
rosy red.

Discussion: The short, white spines arising from the red exterior and the rich
pinkish streaking of the interior distinguishes this elegant small species from all others.
It is rarely collected and appeared endemic to Clarion Island until a specimen was
collected in the Galapagos Islands (Keen 1971).

The species is generally cemented to small pebbles, or exists as colonies in
fissures and on the underside of boulders in 27 to 55 meters. The northward range
is Clarion Island, Mexico (18°22'N), extending southwards on the mainland coast
to Isla del Tigre, Honduras (13°16'N). It is a frequent component of the rocky sub-
strate epifauna of Barrington Island, Galapagos Group (0°51'S), but does not occur
so far south on the mainland coast.

Pseudochama corrugata (Broderip 1835)

Figures 7 g, h

Chama corrugata Broderip 1835a: 150 (Type locality: Corinto, Nicaragua, 12°29'N. Paratype
BM(NH) 1950.11.1.23); Broderip 1835b:305, pi. 38, fig. 7; Reeve 1847: pi. 2, fig. 9;
Clessin 1889:37, pi. 16, fig. 2; Lamy 1910:88.

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Pseudochama corrugata (Broderip), Olsson 1961:226, pi. 34, fig. 4-4d; Keen 1971:151,
fig. 355.

Shell highly variable, sculpture generally obscure, sometimes with broad folia-
tions, exterior radially grooved, often with brown lines. Interior with extensive
purple staining.

Discussion: This is the largest of western American Pseudochama and is easily
recognized by the extensive purple staining of the shell interior. It is the common-
est off the northern Peruvian coast, more rarely occurring off Panama, and sporad-
ically to the Gulf of California, Mexico. It is a warm water species and does not
extend into the cool water south of Point Aguja, Peru. The geographic range is
from Sechura Bay, Peru (5°40'S), to Isla Partida, Mexico (28°52'N). P. corrugata
is generally cemented to rock in exposed locations, more rarely on dead bivalve
shell, in the intertidal zone to 5 meters.

Pseudochama dalli new name
Figure 12 d

Chama inermis Dali (Carpenter MS) 1871:148 (Type locality: unknown: not Puget Sound,
Washington. Holotype USNM 24108). Not Chama imbricata inermis Deshayes 1863.
Pseudochama inermis (Dali), Palmer 1963:307, pi. 61, fig. 8-10; Keen 1971:151, fig. 356.

Shell smooth, covered by a thin adherent brownish yellow periostracum. Free
valve may bear a purple ray. Interior white, sometimes with a purple brown patch.
Margin smooth.

Discussion: This rare species is readily identifiable by the lack of exterior pro-
cesses and the thin shining periostracum. It may possibly be a teratological specimen
of P. panamensis (Reeve) but until more material is available the taxon must be re-
tained. The holotype was obtained supposedly from Puget Sound by J. Rowell,
who collected from California to Panama. This material was deposited in the
Smithsonian Institution and examined by P. P. Carpenter, who correctly surmised
that it was tropical and not from Puget Sound. Because of the doubtful type locality
Carpenter did not release his manuscript name and description for this species.
Dali published the name; however, it is preoccupied by Deshayes (1863) for a
variety of Chama imbricata Broderip 1835 from the Indian Ocean. Pilsbry and
Lowe (1934) illustrate a fine specimen collected in 1930 from the Tres Marias
Islands off Mexico. The species occurs from Panama Bay, Panama (9°N) to Tres
Marias Islands, Mexico (21°26'N) and has been collected only from wooden pil-
ings at the subtidal level to 5 meters. The type location, Tres Marias Islands,
Mexico (21°26'N) is here designated.

Pseudochama exogyra (Conrad 1837)

Figures 10 d-f

Chama exogyra Conrad, 1837:356 (Type locality: Santa Barbara, California, 34°23'N. Syn-
types BM(NH) 1961.5.20.155); Reeve 1847: pi. 7, fig. 38; Tryon 1872:117; Clessin
1889:26, pi. 10, fig. 5; Lamy 1927:337.

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Pseudochama exogyra (Conrad), Durham 1950:73, pi. 17, figs. 4, 13 (Pliocene to Recent
of Mexico); Addicott 1964:146 (Pleistocene of California); Yonge 1967:49; Smith and
Gordon 1948:173.

Pseudochama grand Strong 1934:137, pi. 8, figs. 6, 7 (Type locality: Clarion Island, Mexico,
18°N. Holotype CAS 5808); Smith and Gordon 1948:137; Dibblee 1966:58 (Pleistocene
of California).

Shell white, sometimes splashed with red, more rarely with green. Sculpture
of concentric lamellae that may be produced into broad spines. Interior white,
inner margin smooth; commissural shelf may be wide.

Discussion: This most northerly representative of Pseudochama may be diffi-
cult to recognize due to excessive abrasion and obliteration of the surface detail, but
the plain shell margins and translucency of the exterior surface made it unlikely
to be confused with other species. I consider P. grand Strong the subtidal form in
which the sculpture tends to be smaller and more regular, less likely to be eroded.
The type variant of P. exogyra is intertidal or just subtidal, and is distributed from
central Oregon (approximately 44°N), to San Diego, California (32°40'N). P. grand
occurs from 20 to 155 meters and extends from the southern British Columbia bor-
der (48°N) to San Benito Island, Mexico (28°N). In 1962 I collected a single speci-
men in 155 meters off the west coast of the Queen Charlotte Islands (53°N). Clarke
and Clarke (1974) reported a single specimen of P. exogyra from a Nootka Indian
shell midden on the west coast of Vancouver Island, British Columbia (49°35'N).
A number of other molluscan species have been collected from time to time far
from their normal range. These chance occurrences cannot be considered part of the
normal distribution pattern as the errant specimens do not constitute established,
breeding populations.

Odhner (1919) considered P. exogyra to be identical to echama rotunda Clessin,
1889 from the Gulf of Mexico. I do not agree with his conclusion.

Pseudochama janus (Reeve 1847)

Figure 11 a, b

Chama imbricata var a Broderip 1835a: 149 (Type locality: Galapagos Islands. Syntypes
BM(NH) 1950.11.1.36-38); Broderip 1835b:304, pi. 39, fig. 3; Soot-Ryen 1931:314.
Chama janus Reeve 1847: pi. 7, sp. 36 (Type locality: Galapagos Islands. Syntypes BM(NH)
1950.11.1.36-38); Clessin 1889:43, pi. 17, fig. 6; Lamy 1927:340.

Pseudochama janus (Reeve), Keen 1971:151, fig. 357.

Exterior with a uniform elegant brown striping. Upper valve medially bisected
into two distinct surface patterns of ornamentation, the posterior section with brown
lines and a few short scales. Interior white, margins crenulated only on dorsal
posterior portion.

Discussion: The medial bisection of the free valve into two distinct pattern
zones readily distinguishes this species from all other west American chamids.

There is no doubt that material from different locations was included by
Broderip when he proposed C. imbricata. The nominate species is a common
Indo-Pacific chamid, while var a is Galapagan and Reeve was correct in suggest-

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ing a new name. Odhner (1919) considered/5, janus synonymous withP. corrugata
(Broderip 1835), a totally unwarranted conclusion. The species appears endemic
to the Galapagos Islands, cemented to molluscan shells in 10 to 25 meters. Osorio
and Bahamonde (1970) record C. imbricata Broderip 1835 from the Juan Fernandez
Islands (33°S), and the literature contains records of P. janus from Mexico. I have
been unable to confirm these records and consider them probably due to misidenti-
fication ofP. panamensis (Reeve 1847).

Pseudochama panamensis (Reeve 1847)

Figures 12 a-c

Chama panamensis Reeve 1847: pi. 8, sp. 45 (Type locality: Panama. Holotype (BM(NH)
1950.11.1.23); Clessin 1889:32, pi. 13, fig. 5; Lamy 1927:330.

Pseudochama panamensis (Reeve), Olsson 1961:225, pi. 33, fig. 1-lb; Keen 1971:151,
fig. 358.

Shell generally dorsoventrally prolonged. Exterior white, with delicate lines
of brown. Attached valve with a few hyote spines. Free valve with concentric
rows of wide longitudinally ribbed imbricated spines and a small area of the dorsal
posterior portion with concentric scales. Interior white, sometimes with patches of
brown or yellow, shell margins smooth. Attachment area extensive.

Discussion: This species, though with a wide range, is of sporadic occurrence.
The ribbed imbricated spines of the upper valve and small zone of concentric lamel-
lae (“two-fold structure” of Reeve) easily distinguish it from other chamids. How-
ever, specimens with poor sculpture and heavy brown striping may be mistaken
forP. janus (Reeve). This species appears limited to clefts and fissures in massive
rocks from the middle tidal level to 10 meters. The range is from Gonzaga Bay,
Gulf of California, Mexico (29°50'N) to Cape San Francisco, Ecuador (0°40'N).
The original type locality “Panama” is vague, so Punta Garachina, Panama (8°07'N,
78°39'W) is here designated the type locality.

Pseudochama saavedrai Hertlein and Strong 1946
Figures 8 d-f

Pseudochama saavedrai Hertlein and Strong 1946:110, pi. 1, figs. 1, 3, 8, 10. (Type locality:
Manzanillo, Mexico, 19°00'N, in 45 meters. Holotype CAS 9189A.); Hertlein 1957:63
(Pleistocene of Mexico); Keen 1971:151, fig. 359.

Shell white to light yellow. Lower valve with concentric appressed lamellae.
Upper valve ornamented with concentric longitudinally striated lamellae, pro-
longed into two radial rows of wide imbricated spines. Interior white, margins
coarsely crenulated, comissural shelf wide. Attachment area small.

Discussion: The species is readily distinguished by the overlapping lamellae
produced into two radial rows of spines. The holotype is a poor specimen and does
not do justice to the beauty of this species. Material from Panama in the Allan Han-
cock Foundation holdings and other collections is more solid than Mexican repre-
sentatives and the lamellae are shorter and coarser but it is undoubtedly this species.

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29

P. saavedrai is frequently attached to dead shells in regions of small cobbles
and rock fragments in the low intertidal to 55 meters. In ranges from Puerto Penasco,
Gulf of California, Mexico (31°20'N) to Chacahua Bay, Mexico (15°55'N) and
the Allan Hancock Foundation has material from Secas Island, Panama (7°58'N).

ACKNOWLEDGMENTS

My sincere appreciation is due to J. S. Garth, Senior Curator (now Professor
Emeritus) of the Allan Hancock Foundation, for placing the chamid collection in
my hands. As this material largely consists of detached, often juvenile, valves
unsuitable for illustration, I am indebted to fellow workers, notably S.S. Berry,
C. Angermeyer, and the late W. J. Eyerdam, who donated specimens that are now
on deposit in the Los Angeles County Museum of Natural History. I am also in-
debted to K.M. Way of the British Museum (Natural History) for furnishing bio-
graphical details of certain nineteenth century collectors and to J. Rosewater of
the United States National Museum for the loan of type material. I am grateful to
E. V. Coan, A. M. Keen and J. H. McLean for generous advice and constructive
criticism.

RESUMEN

Diecinueve especies de Chamidae viven en el Pacifico Oriental Americano
y predominan en aguas templadas poco profundas. Las amplias colecciones de la
Fundacion Allan Hancock de la universidad del Sur de California proporcionan
las bases para esta revision sistematica y distributiva. Se concluye que se ha determ-
inado geneticameente la valva de u ion. Se presenta una nueva interpretacion de
la ontogenesis principal. Se propone el nombre Pseudochama dalli para un nombre
ya asignado. Tambien se proponen tres nuevas especies Chama arcana, C. garthi
y C. tinctoria.

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Figure 4. (a) Chama arcana new species, Newport Bay, California, holotype, LACM 1723;
(b) Chama arcana new species, Monterey, California, LACM A8881.1; (c) Chama pellucida
Broderip, Iquique, Chile, topotypes, LACM A8881.2; (d) Chama chilensis Philippi (= C.
pellucida ), Pliocene, Laguna de Cahuil, Chile, holotype, MNHN no number. Scale = 1 cm.

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31

Figure 5. (a) Chama tinctoria new species, Bahia Honda, Panama, holotype, AHF 169;
(b) Chama tinctoria new species, Bahia Honda, Panama, paratype, AHF 170; (c) Chama
tinctoria new species, Panama Bay, Panama, MNHN no number; (d) Chama buddiana C. B.
Adams, Isla del Rey, Panama Bay, Panama, LACM A8881.3; (e) Chama buddiana C.B.
Adams, Albemarle Island, Galapagos Islands, Ecuador, LACM A8881.4. Scale = 1 cm.

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Figure 6. (a) Chama sordida Broderip, Isle of Cuna, Central America, syntype, BM(NH)
1950.11.1.52; (b) Chama sordida Broderip, Gorgona Island, Colombia, AHF 1262; (c) Chama
corallina Olsson, Punta Escondido, Panama, holotype, USNM 701157; (d) Chama corallina
Olsson, Isla Cinche, Bahia Honda, Panama, LACM A881.5; (e) Chama corallina Olsson, Gulf
of California, Mexico, Mrs. E. E. Wahrenbrock; (f) Chama corallina Olsson, Punta Escondido,
Panama, topotype, AHF 1264; (g) Arcinella californica (Dali), Cedros Island, Mexico, holo-
type, USNM 96252. Scale = 1 cm.

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33

Figure 7. (a) Chama echinata Broderip, Puerto Portrero, Ecuador, syntype, BM(NH)
1950.11.1.21; (b) Chama echinata Broderip, Banderas Bay, Mexico, LACM A8881.6;
(c) Chama echinata Broderip, Isla Bona, Gulf of Panama, Panama, LACM A8881 .7; (d) Chama
echinata Broderip, Banderas Bay, Nayarit, Mexico, LACM A8881.19; (e) Chama echinata
Broderip, Cedros Island, Mexico, LACM A8881.8; (f) Chama coralloides Reeve (= C. echi-
nata), Puerto Portrero, Ecuador, holotype, BM(NH) no number; (g) Pseudochama corrugata
(Broderip), Tumbez, Peru, CAS 36666; (h) Pseudochama corrugata (Broderip), Caleto Mero,
Peru, CAS 36661. Scale = 1 cm.

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Figure 8. (a) Chama frondosa Broderip, Isla La Plata, Ecuador, holotype, BM(NH) 1950.
11.1.55; (b) Chama frondosa Broderip, Isla La Plata, Ecuador, paratype, BM(NH) 1950.
11.1.54; (c) Chama parasitica Rochebrune (= C. frondosa), San Jose Island, Mexico, holo-
type, MNHN no number; (d) Pseudochama saavedrai Hertlein and Strong, Manzanillo, Mex-
ico, holotype, CAS 9 189 A; (e) Pseudochama saavedrai Hertlein and Strong, Manzanillo,
Mexico, topotype, LACM A5498; (f) Pseudochama saavedrai Hertlein and Strong, Secas
Island, Panama. LACM A8881.9. Scale = 1 cm.

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35

Figure 9. (a) Chama garthi new species, Octavia Bay, Colombia, holotype, AHF 167;
(b) Chama garthi new species, Octavia Bay, Colombia, paratype, AHF 168; (c) Chama
squamuligera Pilsbry and Lowe, Santa Cruz Island, Galapagos Islands, Ecuador, LACM
A8881.10; (d) Chama squamuligera Pilsbry and Lowe, Barrington Island, Galapagos Islands,
Ecuador, LACM A8881.ll; (e) Chama spinosa Broderip, South Marutea (extralimital),
holotype, BM(NH) no number. Scale = 1 cm.

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Figure 10. (a) Chama producta Broderip (= C. mexicana ), Gulf of Tehuantepec, Mexico,
holotype, BM(NH) 1950.11.1.60; (b) Chama frondosa fornicata Carpenter (= C. mexicana ),
Mazatlan, Mexico, syntype, BM(NH) Carpenter Collection 440; (c) Chama mexicana Car-
penter, Bahia Concepcion, Baja California, Mexico, LACM A8881.12; (d) Pseudochama
exogyra (Conrad), Santa Barbara, California, syntypes, BM(NH) 1961.5.20.155; (e) Pseudo-
chama exogyra (Conrad), Vancouver Island, British Columbia, Canada, LACM A8881.13;
(f) Pseudochama exogyra (Conrad), Catalina Island, California, LACM A8881.14; Scale
= 1 cm.

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Eastern Pacific Chamidae

37

Figure 11. (a ) Pseudochama janus (Reeve), Galapagos Islands, Ecuador, holotype, BM(NH)
1950.11.1.36; (b) Pseudochama janus (Reeve), Albemarle Island, Galapagos Islands, Ecuador,
LACM A8881.15; (c) Chama digueti Rochebrune (= C. venosa), San Jose Island, Mexico,
syntypes, MNHN no number; (d) Chama venosa Reeve, Guaymas, Gulf of California, Mexico,
BM(NH) no number; (e) Chama venosa Reeve, locality unknown, holotype, BM(NH)
1950.11.1.4. Scale = 1 cm.

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Figure 12. (a ) Pseudochama panamensis (Reeve), Panama, holotype, BM(NH) 1950.11.1.23;
(b) Pseudochama panamensis (Reeve), Bahia Gonzaga, Gulf of California, Mexico, LACM
A8881.16; (c) Pseudochama panamensis (Reeve), La Paz, Baja California, Mexico, MNHN
no number; (d) Pseudochama dalli new name (= C. inermis ), Panama Bay, Panama, BM(NH)
no number; (e) Pseudochama clarionensis Willett, Barrington Island, Galapagos Islands,
Ecuador, LACM A8881.17; (f) Pseudochama clarionensis Willett, Clarion Island, Mexico,
LACM A8881.18. Scale = 1 cm.

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39

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Nat. Hist. 2(B): 143-409, pis. 1-57.

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Eastern Pacific Chamidae

41

Hertlein, L. G., and A.M. Strong. 1946. Eastern Pacific expeditions of the New York
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1955. Marine mollusks collected at the Galapagos Islands during the voyage of the

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Keen, A.M. 1962. Nomenclatural notes on some west American mollusks, with proposal
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xiv + 1064 pp, 22 pis, approx. 3400 figs.

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1927. Revision des Chama vivants du Museum National d’Histoire Naturelle de

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1, Regnum animale, part 2, p. 533-1327.

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1952b. Designation of the type species of Pseudochama (additional note). Jour.

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Accepted for publication January 22, 1976

61, 73

uLuf

NUMBER 279
JULY 7, 1976

OSTEOLOGY AND RELATIONSHIPS
OF THE ROOSTERFISH, NEMATIST1US
PECTORALIS GILL

By Richard H. Rosenblatt and
Michael A. Bell

.

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OSTEOLOGY AND RELATIONSHIPS OF THE ROOSTERFISH,
NEMATISTIUS PECTORALIS GILL1

By Richard H. Rosenblatt2 and Michael A. Bell3

Abstract: The status of the roosterfish, Nematistius pectoralis, long has been in
doubt. It alternatively has been considered a member of the Carangidae or to repre-
sent a monotypic family. An investigation of the osteology of A. pectoralis indicates
that it should not be placed in the Carangidae, but merits separate familial status.

N. pectoralis differs from members of the Carangidae in that the gas-bladder enters
the skull through large foramina in the basioccipital and contacts the inner ear, the
three anal spines are normally arranged, and the interosseus space of the shoulder
girdle is well developed. The two families are similar, however, in most other
skeletal features and are regarded as closely related.

Patterson’s suggestion that the Carangidae have been derived independently
from the Beryciformes is not supported. His primary indicator of relationships,
caudal rays with forked bases that clasp the hypurals, has been developed inde-
pendently in a number of unrelated lineages. Other resemblances between the
Cretaceous berycoid genus Aipichthys and modem carangids are regarded as prod-
ucts of convergent evolution.

INTRODUCTION

Nematistius pectoralis, the roosterfish or papagallo, is a large, fast swimming,
predaceous fish of the eastern tropical Pacific (Fig. 1). The most striking external
feature of the species is the presence of elongate, free dorsal spines, which account
for the generic and vernacular names.

Figure 1. N. pectoralis, a living adult. In normal swimming the elongated dorsal spines are
folded down. (Photograph by E. M. Hobson.)

The familial placement of Nematistius fairly can be termed an ichthyological
football. It variously has been regarded as a member of the Carangidae (Boulenger
1910; Regan 1913; Greenwood et al 1966) or placed in a separate family (Gill 1864;
Jordan and Evermann 1898; Berg 1947; Freihofer 1963). It will be noted that some of
the most distinguished names in the history of ichthyology are ranged on either
side of the question.

Review Committee for this Contribution
Robert J. Lavenberg
Colin Patterson
William F. Smith-Vaniz
Camm C. Swift

2Scripps Institution of Oceanography, (University of California, San Diego), La Jolla,
California 92037

3Research Associate in Ichthyology, Natural History Museum, and Department of Biology,
University of California, Los Angeles, California 90024.

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No. 279

Considering the unfavorable ratio of ichthyologists to fishes, it is perhaps
not surprising that no one has attempted to settle the matter by an investigation of
the internal anatomy of Nematistius pectoralis. Starks (1908) briefly described the
connection between the inner ear and the gas bladder (otophysic connection, vide
Greenwood et al 1966); Berg (1947) pointed out its possible taxonomic signifi-
cance; and Freihofer (1963) indicated that the ramus lateralis accessorius nerve
conformed to his Pattern 10, in distinction to the Carangidae, but that is all. An
investigation of the osteology of Nematistius is made more meaningful by the recent
publication of extensive descriptions of the osteology of a number of carangid
genera and species (Suzuki 1962).

MATERIALS AND METHODS

Dried, partly disarticulated preparations as well as stained and cleared speci-
mens were used. Details of the gas-bladder connection with the inner ear were
worked out by dissecting specimens in which the gas-bladder had been filled with
latex. In the following material list (S) refers to a stained specimen, and (D) to a
dried preparation. The material used in this study is housed in the collections of
the Scripps Institution of Oceanography (SIO), Biology Department, University
of California, Los Angeles (UCLA) and the National Marine Fishery Service, South-
west Fisheries Center, La Jolla (BCF).

Nematistndae-Nematistius pectoralis. SI062-22, entire skeleton of an 886 mm
(fork length) adult (D); SIO unnumbered, head and appendicular skeleton of an
adult (D); UCLA S402, two neurocrania and vertebral columns (D); UCLA A-225
3 (32-79.5) (S); UCLA W53-297, 1 (17.5) (S).

Carangidae-Ctfraflx melampygus, BCF422-26 (S); Chloroscombrus chrysurus
BCF422-19 (S); Decapterus sp. SIO unnumbered (D); Gnathanodon speciosus BCF
422-17 (S); Hemicaranx zelotes BCF422-6 (S); Selene oerstedi BCF422-2 (S); S.
vomer BCF422-22 (S); Seriola dorsalis SIO unnumbered (D); S. mazatlana SIO
57-16 (D); Trachinotus carolinus BCF422-5 (S); T. falcatus BCF422-21 (S); T.
goodei BCF422-23 (S); Vomer declivifrons BCF422-11 (S); V. setapinnis BCF422-9,
BCF422-20 (S).

Scombridae-Stf/r/tf chiliensis, SIO unnumbered (D); Scomber japonicus, SIO
unnumbered (D); Thunnus obesus, SIO unnumbered (D).

Cory phaemdae-Coryphaena hippurus SIO54-160 (D).

Engraulididae-.4flc/i0tf sp. SIO unnumbered (S).

Stromateida e-Peprilus sp. SIO unnumbered (S).

Serranida e-Mycteroperca jordani SIO62-706 (D).

Kyphosida e-Girella nigricans SIO unnumbered (D); Medialuna calif orniensis
SIO unnumbered (D).

OSTEOLOGY

Neurocranium. — (Figs. 2, 3). Bones of neurocranium relatively dense, except
for cancellous areas along anterodistal margin of supraoccipital, dorsolateral portions
of lateral ethmoids, and ventrolateral margins of frontals.

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Roosterfish Osteology

3

Figure 2. TV. pectoralis, neurocranium. A — side view, B — top view, C — bottom view. Abbre-
viations: BO, basioccipital; BOF, basioccipital foramen; BS, basisphenoid; EO, exoccipital; EP,
epiotic; FM, foramen magnum; FR, frontal; LE, lateral ethmoid; ME, mesethmoid; OO,
opisthotic; PA, parietal; PR, prootic; PS, parasphenoid; PSF, parasphenoid foramen; PT,
pterotic; PTS, pterosphenoid; SO, supraoccipital; SP, sphenotic; V, vomer (prevomer).

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Neurocranium deep, and relatively broad anteriorly; its outline subrectangular
when viewed from above. The most prominent features are the lateral crests and
median crest. The ventralmost crest is formed by the pterotic and frontal, the next
by the epiotic, parietal and frontal, and the medial crest by the supraoccipital,
frontals, and, to a minor extent, mesethmoid.

Mesethmoid roughly cruciform in anterior view, with dorsal ridges on the
lateral arms and a pronounced median ridge that continues downward onto anterior
face of vomer (prevomer). Vomer deep, with a relatively short shaft. Tooth patch
ovoid. Lateral ethmoids with large openings for olfactory tracts. Nasals ligament-
ously attached to ethmoids.

Roof of orbital cavity formed mainly by frontals, pterosphenoids and sphenotics.
Anterior opening of braincase bounded by pterosphenoids and basisphenoid. Ptero-
sphenoids not meeting across midline, but with medial processes posteriorly, which
almost come in contact. Basisphenoid in contact with pterosphenoids and prootic
dorsally and parasphenoid ventrally. Myodome large and deep.

Figure 3. Neurocranium of N. pectoralis, rear view. Abbreviations as in figure 2.

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Roosterfish Osteology

5

Parasphenoid with a sharp keel to just behind level of orbital cavity, then
expanded laterally and flattened. Parasphenoid in contact with vomer and lateral
ethmoids anteriorly, and with prootic and basioccipital posteriorly. Posterior open-
ing of myodome developed as a large canal bounded dorsolaterally by basioccipital
and ventrolaterally by parasphenoid. Basioccipital contacting prootic anteriorly,
parasphenoid ventrally, first vertebra posteriorly, and exoccipitals anteriorly.

On either side of basisphenoid, beneath and lateral to condyle, are two canals
with posterior openings that lead into the auditory bulla. Each canal receives a
process from the gas-bladder. These anterior processes of the gas-bladder extend
forward to the region of the inner ear, but do not come in contact with it. Our obser-
vations thus confirm those of Starks (1908). The exoccipitals, bounded by the supra-
occipital, epiotics, pterotics, opisthotics, prootics and basioccipital, are in contact
along the midline, above and below the foramen magnum.

Opisthotic almost excluded from top of skull by the overlying pterotic and exoc-
cipital. Pterotic with a strong backward projection, and a long socket which receives
one facet of head of hyomandibular. At junction of the pterotic, epiotic and parietal
there is an unossified area bridged by cartilage.

Prootic forming a major part of the posterolateral wall of the neurocranium.
At its anterodorsal comer it, together with the sphenotic, forms a deep socket for
an articular facet of the hyomandibular. Pars jugalis with but two openings, thus
agreeing with other perciforms (Patterson 1964:434-438).

Supraoccipital with a high crest, which extends far forward over frontals, and
posteriorly to exoccipital. Superficially frontals in contact for only a short distance;
they are separated by the supraoccipital posteriorly and the mesethmoid anteriorly.

The general shape of the jaws is indicated in figure 4. The maxilla fits closely
into the groove on the dorsolateral surface of the premaxilla and is braced anteriorly
against the palatine. Supramaxilla rather loosely attached to maxilla. Premaxilla
with two ascending processes anteriorly and a lower one posteriorly. The ascending
(anteriormost) process contacts the mesethmoid and the posterior ones contact the
maxilla. The premaxilla is very similar to those illustrated by Suzuki (1962) for
various carangid genera. The lower jaw is of normal perciform type, except that
the angular (retroarticular) is fused to the articular (angular).

Suspensorium. — (Fig. 5). Suspensorium and opercular bones well integrated.
Posterolateral face of hyomandibular deeply grooved to receive ascending process
of preopercle. Palatine with a narrow band of teeth.

Symplectic firmly joined to quadrate and metaptergyoid, and metapterygoid
further united with hyomandibular and, on its inner face, with ectopterygoid.

Hyoid Apparatus. — (Fig. 6). Ceratohyal and epihyal firmly united by deep su-
tures on medial face. A well-developed, elongate-oval foramen in ceratohyal, from
which a groove runs anteriorly and posteriorly along its lateral face. Posteriorly, this
groove continues onto epihyal, forming a deep excavation. There are seven branch-
iostegals, three articulating with the inner face of the ceratohyal, two with its outer
face, and two with the outer face of the epihyal.

Orbital Bones. — (Fig. 7). Six suborbital bones, including dermosphenotic (only
the first four are figured). Lachrymal without the outward curvature described by

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Figure 4. Jaws of N. pectoralis. A — maxilla and supramaxilla; B — premaxilla; C — lower jaw.
Abbreviations: AN, angular (articular); AR, articular (retroarticular); DE, dentary.

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Roosterfish Osteology

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Figure 5. Suspensorium and opercular apparatus of N. pectoralis. A — outer face; B — inner
face. Abbreviations: EC, ectopterygoid; ET, entopterygoid; HD, hyomandibular; IO, inter-
opercle; MT, metapterygoid; OP, opercle; PO, preoperacle; PT, palatine; QU, quadrate; SO,
subopercle; SY, sympletic.

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Suzuki (1962) for many carangids, but anterior notch characteristic of the Carangidae
weakly developed. Second suborbital trapezoidal and overlapping first, so that it
contacts its outer face rather than its posterior edge for most of its length. Third
circumorbital a thin, curved, inward directed lamina articulating with second along
its upper inner border. Third suborbital forming major part of suborbital ring, in
this respect agreeing with such carangid genera as Elagatis and Naucrates.

Figure 6. Hyoid apparatus of N. pectoralis. A — glassohyal, dorsal view. B — paired elements of
hyoid arch. C — urohyal. Abbreviations: CH, ceratohyal; EH, epihyal; GH, glossohyal; HH,
hypohyals; IH, interhyal; UH, urohyal.

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B

Figure 7. Orbital bones of N. pectoralis, SO 5 and dermosphenotic not shown. A — lateral
view. B — top view.

Limb Girdles. — (Figs. 8, 9). Scapula with two foramina. Anteriorly is the nor-
mal perciform foramen. In Nematistius, the cleithrum forms part of the anterior border
of this foramen on its lateral surface; medially the foramen is completely within
the scapula. Behind this foramen is a second smaller one, which is absent in the
Carangidae, as in all of the perciforms illustrated or described by Starks (1930)
except Cirrhites rivulatus and Scorpaenichthys marmoratus.

All four actinosts borne on scapula. First short and hourglass shaped; remainder
more elongate.

The pelvic girdle bears a striking resemblance to those illustrated by Suzuki
( 1962, Fig. 45). Pelvic plate thin and flattened and with lateral keel. Two sharp keels
ventrally (subpelvic and interpelvic keels of Suzuki). Ischial processes long and
curved.

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Vertebral Column. — There are 10 precaudal and 14 caudal vertebrae, including
the urostylar centrum. Articular facet of first vertebra for basioccipital condyle fac-
ing down and slightly forward, at an angle of approximately 45° to the axis of the
body. Articular surfaces for exoccipital condyles facing almost straight forward.
First neural arch autogenous. Second centrum about half as long as first and two
thirds as long as third. First two neural spines curve forward and are in close con-
tact. They appear fused in some specimens.

First epipleural rib articulating with first neural arch, second with second
centrum, and remaining 5 are borne on pleural ribs. Pleural ribs eight; the first
is associated with third vertebra. First three ribs sessile, remainder borne on

Figure 8. Pectoral girdle of N. pectoralis. Abbreviations: AC, actinosts; CL, cleith-
rum; CO, coracoid; PC, post-cleithra; PT, post-temporal; SC, scapula; SCL, supra-
cleithrum.

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Figure 9. Pelvic girdles of N. pectoralis. IP, ischial process.

parapophyses. First vertebra with parapophyses is the fourth, first with a haemal
arch the eighth. Inferior foramina of Starks (1911) lacking in parapophyses and
haemal arches.

Ventral zygapophyses do not strongly interlock. Dorsal zygapophyses inter-
lock strongly anteriorly, but become opposed by 17th vertebra.

Neural and haemal spines posterior to the 19th vertebra sloping strongly back-
ward, increasing the rigidity of caudal peduncle.

Caudal Skeleton. — (Figs. 10, 11). Principal caudal rays 9 + 8. Caudal rays,
except for middle two, cleft at the base and broadly overlapping skeletal supporting
elements. Procurrent caudal rays borne by neural spine of antepenultimate vertebra
and haemal spines of last two preural vertebrae. Two specimens with 10 procurrent
rays above and 9 below, one with 9 and 8.

Elements associated with ural centrum forming a compact unit. Individual
elements are difficult to distinguish in dried preparations, and more easily discerned
in stained and cleared juveniles (contrast figures 10 and 11). Hypurals reduced by
fusion to four. Upper and lower enlarged hypural plates each represent the fusion
of two hypurals. In small juveniles there is a foramen in the lower expanded hypural
plate, but this becomes obliterated with growth.

Dorsal and Anal Fins. — (Figs. 12, 13). Three median bones in advance of dorsal
fin. We follow the terminology of Smith and Bailey (1961) who termed these struc-
tures predorsal bones. The first interneural element is an enlarged structure that
bears two spines. The arrangement of three ray-less elements, followed by one
which bears two rays is 0 -0 -0 -2 in the shorthand terminology of Smith and Bailey.
For reasons given in the discussion, we regard the expanded element in Nematistius
as representing the fusion of the first pterygiophore with the proximal and me-
dial radials of the second pterygiophore. The first three anal spines are closely
approximated, rather than unequally spaced as in the Carangidae, nor is the first
anal pterygiophore as stout and expanded ventrally. However, the structure

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No. 279

EP

Figure 10. Caudal skeleton of a large juvenile A. pectoralis (dried preparation). Abbre-
viations: EP, epural; HP, hypural; HPP, hypurapophysis; HS, haemal spine; NS, neural
spine; UN, uroneural; UR, urostyle.

NS EP

Figure 1 1 . Caudal skeleton of a cleared and stained 32.5 mm juvenile of N. pectoralis. Abbrevia-
tions as in figure 10.

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Figure 12. Anterior dorsal fin elements and supporting structures in a 27.5 mm N. pectoralis.
Abbreviations: DR, dorsay ray; NS, neural spine; PB, predorsal bones; PT, pterygiophore.

fundamentally is not different from that found in carangids, and a moderate ex-
pansion of the ventral part of the pterygiophore could carry the first two anal spines
away from the third.

CLASSIFICATION AND RELATIONSHIPS

Nematistius differs in several respects from the forms customarily placed in
the family Carangidae. For comparative data on the Carangidae we have relied
mainly on the important work of Suzuki (1962) and the descriptions of Starks (1911),
although we have utilized skeletal and stained and cleared material as well.

The most important difference is the otophysic connection. The adaptive sig-
nificance of this modification, which would serve to increase both the sensitivity
of hearing and the range of frequencies perceived, is obvious. The formation of the
otophysic connection has involved important changes in the configuration of the
basioccipital and the gas bladder. It is of a type which is, so far as we have been
able to determine, unique.

The remaining characters that serve to isolate Nematistius from the carangids
are less fundamental. There are three normally arranged anal spines, rather than

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two spines detached from the anal and one at its base. This is not a character of obvi-
ous adaptive significance, although it is of great constancy in the Carangidae. The
shoulder girdle, though composed of the same elements as in the Carangidae, is
different in shape in Nematistius . In the Carangidae the coracoid is broad and flat-
tened, and parallel to the cleithrum, from which the lower end sometimes diverges.
As a result, the interosseous space (Starks 1930) is much reduced. In Nematistius
the middle and lower parts of the coracoid are rodlike. The rodlike portion of the
coracoid is well separated from the cleithrum, contacting it only ventrally, so that
the interosseous space is large.

There is also a difference in the arrangement of the predorsal bones. In Nema-
tistius there are two predorsals in advance of the first neural spine and one just
behind its tip. In the carangids that we have examined either there is one predorsal
before the first neural spine and two before the second, or each of the first three
neural spines is preceded by a predorsal bone.

II 12 13

Figure 13. Anterior anal fin elements and associated supporting structures in a 27 mm N.
pectoralis.

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15

Nematistius also differs from many carangids in that the first pterygiophore
is expanded greatly and platelike and bears two spines. The neural spines of the first
two centra are crowded and curved forward to accommodate it. We regard this
enlarged pterygiophore as the product of fusion of two pterygiophores. This is not
in accord with the hypothesis put forward by Smith and Bailey (1961). According
to their scheme, in a fish with 3 predorsals and 2 spines on the first proximal pterygio-
phore (0 -0 -0 -2), the first spine has been displaced backward from the third pre-
dorsal bone. However, this does not allow for the derivation of the 0 -0 -0 -2
condition from an ancestor with the 0 -0 -0 -1 condition. And the trends indicated
in Smith and Bailey’s plate I do not admit such a possibility. However, in the Carang-
idae both arrangements occur, as well as one not noted by Smith and Bailey,
0 -0 -0 -0 -2 in Trachinotus. (It should be noted that the arrangement in Vomer
setapinnis is 0 -0 -0 -2, not 0 -0 -0 -0 -0-0-1 as indicated by Smith and Bailey).

It seems to us that it is simpler to derive the 0 -0 -0 -2 condition from the
0 -0 -0 -1 (especially in the Carangidae, in which the former condition appears to
have been derived from the latter several times), by invoking a fusion of two pterygio-
phores, rather than the moving back of the spine and subsequent or simultaneous
loss of the rayless pterygiophore. In Trachinotus , however, it is clear that the first
spine has migrated backward, because its pterygiophore persists as a fourth pre-
dorsal bone. It is likely that studies of the ontogeny of the dorsal fin in carangids
will help clarify this admittedly unsettled question.

The 0 -0 -0 -2 condition, however, has been derived independently in Nema-
tistius and certain carangid genera, since primitive carangids such as Seriola and
Naucrates have the 0 -0 -0 -1 condition.

We believe that the first three differences discussed above are sufficient to
indicate the placement of Nematistius in a family distinct from the Carangidae. Nor
does the set of features exhibited by Nematistius warrant its inclusion in any other
fish family. However, the Nematistiidae does agree with the Carangidae in a num-
ber of features, and the families are closely related. The similarity in general appear-
ance and in the deeply forked caudal, with the rays clasping the skeletal supporting
elements, could be ascribed to convergence. The suite of osteological similarities
displayed by the two groups, however, are not so easily explained on this basis.

The neurocranium of a carangid has a very characteristic appearance caused
by the strong development of medial and lateral crests. The neurocranium of Nema-
tistius is extremely similar to that of certain high-headed, short-snouted carangid
genera. Only the tell-tale tunnels on the lateral faces of the basioccipital would allow
the separation of a Nematistius skull from a group of carangid skulls. Even the
peculiar posterior flattening of the parasphenoid of Nematistius is paralleled in
Trachinotus. The circumorbital bones of carangids are likewise distinctive (Suzuki
1962, Figs. 35, 36; Smith and Bailey 1962, plate 3 Q), in that the third suborbital
(2SO of Suzuki) bears a broad lamina and articulates with the second mainly along
its upper inner edge, rather than posteriorly. The resemblance between the suborbital
bones of Nematistius and such primitive carangid genera as Elagatis, Naucrates
and Seriola is striking. Another pecularity shared by the two groups is in the struc-
ture of the pelvic girdle. In both, the anterior parts of the pelvic bone are thin but

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broad, with flanges produced ventrally to provide deep grooves for muscle attach-
ment, and the posterior (ischial) processes are elongate and well developed. This
characteristic facies can be seen in Suzuki’s figures 45A-R, and our figure 9.

The otolith of Nematistius resembles that of Seriola and Caranx in that the
rostrum is long and there is a deep notch above it. It further resembles that of Seriola
in the form of the sulcus ( Caranx differs somewhat from the other two genera in
this respect) and in the serration of the lower margin. The otolith of Nematistius is
more massive and more crystalline in structure than that of either carangid, but is
not very different in either respect (compare figures 14 and 15).

Certain other points of similarity are perhaps of less value, but still serve to
emphasize the overall similarity of Nematistius to the Carangidae. These include
the presence of a well-developed foramen in the ceratohyal and the shape of the
hyomandibular, which has a deep groove on its lateral face for the reception of
the preopercle.

It is perhaps not surprising that the caudal skeleton of Nematistius should
resemble that of carangids, considering the similarity of function. Although in most
carangids there has been more fusion of elements (compare figures 10 and 11 and
figure 16), the caudal skeleton of the primitive but specialized Trachinotus (Fig. 17)
is like that of Nematistius in the retention of three epurals.

The differences between the Nematistiidae and the Carangidae are those of
specialization and no feature militates against the derivation of Nematistius from
a generalized carangid or protocarangid. However, no extant genus qualifies as
an ancestor. All of the subfamilies considered primitive by Suzuki are specialized
in having two detached anal spines. In the Chorineminae ( = Scomberoidinae) the
premaxillary is non-protractile, and in the Trachinotinae the supramaxillary has been
lost, the pharyngeals are enlarged, and there is a lateral peg on the basioccipital for
the attachment of a heavy ligament. Members of the Naucratinae are less specialized,
but in addition to the aforementioned difference in arrangement of anal spines, the
caudal skeleton of Seriola (the only naucratine genus examined osteologically by us)
is specialized in fusion and loss of elements present in Nematistius .

Freihofer (1963) found that the Carangidae and Nematistiidae differ in the
course of the nerves of the ramus lateralis accesorius (RLA), the former having
pattern 9 and the latter pattern 10 (reduced). He believed that this means that the
Carangidae and Nematistiidae are unrelated and that affinities should be sought
among other groups with pattern 10. He stated that “Nematistius pectoralis most
closely resembles Medialuna calif or niensis which also has pattern 10” and “Cursory
examination of the skeletons of Nematistius and Kyphosus reveals enough general
similarities falling within the entire conspectus implied by the Pattern 10 assemblage
to leave the hypothesis stand as a good one for future testing.”

We have compared the skeleton of Nematistius with those of Medialuna cali-
fornensis and Girella nigricans. The general similarities indeed are sufficient to
indicate an ordinal relationship. Neither form either exhibits or foreshadows the
peculiarities of Nematistius . Without repeating them, neither are the peculiarities
shared by the Nematistiidae and Carangidae found here. Noteworthy differences
include the lack of lateral crests on the skull and the restriction of the supraoccipital

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Figure 14. Right sagitta of N. pectoralis. A — medial face. B — lateral face.

Figure 15. Right sagitta of Caranx marginatus, medial face.

Contributions in Science

No. 279

crest, which does not encroach on the frontals, which in turn lack a crest. Also the
shape of the jaw bones is very different in these nibbling forms. In short, once com-
mon perciform characteristics are eliminated, there is little in the osteology of medi-
aluna and Girella to support the contention that they are especially closely related
to Nematistius . There is only the evidence of the RLA pattern, and no convincing
proof exists that it is the single characteristic by which teleost phylogenies are to
be deduced.

Patterson (1964) has argued that the Carangidae (and by extension the Nema-
tistiidae) are not perciform fishes, but that instead they have evolved independently
from Beryciformes, and that their perciform characters are due to parallel evolution.
This argument was repeated by Greenwood et al (1966:390) and supported by
Patterson (1968).

This conclusion is based on a series of similarities between the Cretaceous
dinopterygoid beryciform genus Aipichthys and certain carangids. Patterson (1964)

EP

Figure 16. Caudal skeleton of a 50 mm juvenile of Selene vomer. Abbreviations as in figure 10.

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NS

UR + HP

HP

Figure 17. Caudal skeleton of a 73.5 mm juvenile of Trachinotus glaucus. Abbreviations as in
figure 10.

did not cite the work of Suzuki (1962) or Starks (1911) and figured the osteology of
Vomer, one of the most specialized and advanced genera of the Carangidae. His
concept of the family thus was limited. According to him the chief characters linking
Aipichthys with the Carangidae are the “deep trunk and long dorsal and anal fins,
with few spines and with the anterior soft rays elongated. ... the high supraoccipital
crest. ... the upturned highly protrusible mouth, the presence of an elongated
supramaxilla, the number of vertebrae, the form of the cleithrum and coracoid, the
characters of the radials of the dorsal and anal fins, the cycloid scales . . . , and,
in particular, the deeply forked bases of the caudal fin-rays” (1964:397). The resem-
blances between Aipichthys and deep-bodied carangids such as Alectis, Selene,
Trachinotus and Vomer were held to be especially close, and “too detailed to be
due to convergence alone.” The forked caudal rays that clasp the endoskeletal ele-
ments also were held to be an important character indicating relationships (1964:
470). Patterson’s figure of Aipichthys is reproduced for comparison in figure 18.

To begin with, the deep-bodied carangid genera cited by Patterson were regarded
by Suzuki (1962) as specialized and (with the exception of Trachinotus) advanced.
Suzuki regarded the Naucratinae as the most generalized group of carangids and in
this we concur. If, as the osteological evidence indicates, Nematistius represents
an early offshoot from the carangid line, its features must also be accounted for. If

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phylogeny is to have any meaning, ancestral forms must resemble the generalized
representatives of descendant lineages, not the most advanced and specialized ones.

Taking first a similarity utilized by Patterson (1964) that we believe to be more
apparent than real, the supraoccipital crest of Aipichthys is very different from that
of the Carangidae. It apparently stops at the back of the frontals and is not carried
forward by them to the ethmoid as it is in carangids and Nematistius . A crest such
as that of Aipichthys, termed the “chaetodontid type” by Gosline (1966), can be
found in any number of perciforms with short, deep heads. Included would be sev-
eral genera of embiotocids, Calamus (Sparidae), and Medialuna (Kyphosidae),
certainly an unrelated assemblage. In fact, except that the head is less deep and fore-
shortened, the crest of Aipichthys is not basically different from that of certain poly-
mixioid genera illustrated by Patterson (1964, Figs. 76-78). We concur with Gosline
(1966) that it is unlikely that the sharp crest of carangids and Nematistius is derived
from the broad crest of Aipichthys.

The nature of the articulation of the caudal rays to endoskeletal elements is a
poor indicator of relationships. Caudal rays with forked bases that wrap around the

Figure 18. Aipichthys velifer. From Patterson, based on Smith Woodward.

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tail skeleton are found in fish groups that differ greatly in other respects, and thus
must have been evolved independently several times. Such “wrap-around” caudal
rays are of course characteristic of the Scombroidei. They are also found in the
Echeneiformes, some Atheriniformes (Exocoetoidei), and in the perciform suborder
Stromateoidei (Haedrich 1967) ( Peprilus sp. examined) — a quite unrelated assem-
blage. Weitzman (1967) has illustrated such rays (although not so dramatically
developed) in malacopterygian teleosts such as Vinciguerria (Gonostomatidae),
Parasudis (Paralepididae) and Saurida (Synodontidae), and they also occur in the
Engraulididae ( Anchoa examined). The list could be extended, but this should
suffice to document our contention.

The upturned, highly protrusible mouth of Aipichthys is not a character shared
with primitive carangids but with advanced and specialized ones. This sort of mouth,
along with a modified suspensorium, appears in certain advanced carangids with
scutes along the lateral line, a characteristic absent in Aipichthys.

Patterson did not specify the similarities in cleithrum and coracoid, but judging
from his figure, the shoulder girdle of Aipichthys does not differ from that of most
beryciforms, nor, for that matter, from that of generalized perciforms. The coracoid
of Aipichthys certainly does not resemble the broad, almost straight coracoid of
carangids. And, if Patterson’s figure is correct, two pectoral actinosts are borne on
the coracoid in Aipichthys, a character shared neither with the carangids nor most
of the Beryciformes.

We are left, then, with a general resemblance in body form between Aipichthys
and advanced carangids, and the shared characters of elongate and broad dorsal and
anal pterygiophores, a low number of vertebrae and cycloid scales.

The superficial resemblances between Aipichthys and certain advanced carangids
can be ascribed to convergent evolution in fishes with similar ecologies. Certainly
the elongation and broadening of the pterygiophores is an obvious adaptation, which
serves to stiffen the body in deep-bodied fishes, and is by no means restricted to
Aipichthys and the Carangidae.

There thus does not seem to be sufficient basis for the removal of the Nema-
tistiidae and the Carangidae from the Perciformes and the postulation of an inde-
pendent origin of the perciform suite of characters. If the order Perciformes is to be
dismembered, the process must begin elsewhere, and on firmer grounds.

ACKNOWLEDGMENTS

We thank Frederick H. Berry, who persisted in delivering large heaps of frozen
carangids and other large predatory fishes to the Scripps collection, and who insisted
they would come in handy some day. Elbert H. Ahlstrom allowed us to utilize his
extensive collection of stained and cleared fishes, and has discussed various aspects
of the work with us. John E. Fitch loaned sagittae of Caranx and Seriola. Carl L.
Hubbs and F. H. Berry have read the manuscript and offered valuable suggestions.
Figures 2-8 were drawn by Bette Parker, and figures 9-14 were rendered by her from
camera lucida drawings made by one of us (RR). Finally, we thank Moritz Benado
who prepared the Spanish resumen for us.

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No. 279

RESUMEN

La posicion sistematica del papagallo, Nematistius pectoralis, ha estado en
duda por largo tiempo. Ha sido considerado alternativamente como miembro de
la familia Carangidae o como representante unico de una familia monotipica. La
investigacion de la estructura osea sugiere, sin embargo, qu eN. pectoralis no deberia
ser clasificado dentro de la familia Carangidae. N. pectoralis difiere de miembro s
de la familia Carangidae en cuanto a que su vejiga natatoria penetra al craneo a traves
de grandes foramenes en los basioccipitales y toma contacto con el oido interno,
a que el espacio interoseo de la cintura escapular esta bien desarrallado y a que sus
tres espinas anales estan ubicadas normalmente. Sin embargo, ambas familias son
similares en la mayoria de sus otras caracteristicas oseas y, por lo tanto, se considera
que estan estrechamente relacionadas.

Se demuestra que la sugerencia de Patterson de que la familia Caragindae habria
derivado independientemente de la familia Beryciformis carece de fundamentos:
el principal indice de parentesco propuesto por el, rayos caudales con bases ahor-
quilladas que abrazan las estructuras hipurales, se ha desarrollado independiente-
mente en various linajes no relacionados entre si. Otras semejanzas entre el genero
bericoide Aipichthys del Cretaceo y carangidos modernos son considerades el
producto de la evolucion convergente.

LITERATURE CITED

Berg, L. S. 1947. Classification of fishes both recent and fossil. J.W. Edwards, Ann Arbor,
Michigan, English Trans. 517 p.

Boulenger, G. A. 1910. Fishes (Systematic account of Teleostei) In: The Cambridge Natural
History (London), Harmer, S. F. and A. E. Shipley, Vol. 7 (viii+ 760 pp.), pp. 541-727.
Freihoffer, W. C. 1963. Patterns of the ramus lateralis accessorius and their systematic signifi-
cance in teleostean fishes. Stanford Ich. Bull. 8(2):80-189.

Gill, T. 1864. Descriptive enumeration of a collection of fishes from the western coast of Cen-
tral America. Proc. Acad. Nat. Sci. Philadelphia 1863, 15(4): 153-200.

Gosline, W. A. 1966. Comments on the classification of the percoid fishes. Pacific Science,
20(4):409-418.

Greenwood, P. H., D. E. Rosen, S. H. Weitzman, and G. S. Myers. 1966. Phyletic studies
of teleostean fishes, with a provisional classification of living forms. Bull. Amer. Mus.
Nat. Hist. 1 3 1 (4):341 -455 .

Haedrich, R. L. 1967. The stromateoid fishes: systematics and a classification. Bull. Mus.
Comp. Zool. 1 35(2):3 1-1 39.

Jordan, D. S. and B. W. Evermann. 1898. The fishes of North and Middle America. Bull.
U.S. Nat. Mus. 47(1): 1-1240.

Patterson, C. 1964. A review of Mesozoic Acanthopterygian fishes, with special reference
to those of the English Chalk. Phil. Trans. Roy. Soc. London, Ser. B. 247 (739):213-482.

1968. The caudal skeleton in Mesozoic acanthopterygian fishes. Bull. Brit. Mus.

(Nat. Hist)., Geol. 17(2):47-102.

1976

Roosterfish Osteology

23

Regan, C. T. 1913. On the classification of the percoid fishes. Ann. Mag. Nat. Hist.
(8)12(17):1 11-146.

Smith, C. L. and R.M. Bailey. Evolution of the dorsal-fin supports of percoid fishes. Pap.
Michigan Acad. Sci. Arts, Lett. 46:345-363.

1962. The subocular shelf of fishes. Jour. Morph. 110(1): 1-18.

Starks, E. C. 1908. On a communication between the air-bladder and the ear in certain spiny-
rayed fishes. Science 28(722):61 3-614.

1911. Osteology of certain scombroid fishes. Leland Stanford Jr. Univ. Publ. Univ.

Publ. No. 5. 49 pp.

1930. The primary shoulder girdle of the bony fishes. Stanford Univ. Publ. Univ.

Ser., Bio. Sci. 6(2): 149-239.

Suzuki, K. 1962. Anatomical and taxonomical studies on the carangid fishes of Japan. Rep. Fac.
Fish. Prefectural Univ. Mie 4(2):45-232.

Weitzman, S. H. 1967. The origin of stomiatoid fishes with comments on the classification of
salmoniform fishes. Copeia No. 3:507-540.

Accepted for publication March 5, 1976.

NUMBER 280
AUGUST 30, 1976

•Se7, 73
O/ LiCS

ANATOMY OF XYLEM AND PHLOEM OF THE DATISCACEAE

By Christopher Davidson

NATURAL HISTORY MUSEUM OF LOS ANGELES COUNTY

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ANATOMY OF XYLEM AND PHLOEM OF THE DATISCACEAE

By Christopher Davidson* 2

Abstract: The woods of Octomeles and Tetrameles are similar in appearance
and gross morphology. The large diameters and thin walls of the vessel elements
and libriform fibers are responsible for the light-weight, non-durable quality of the
woods; the small amount of wood parenchyma present probably does not contrib-
ute appreciably to this condition. The woods are quantitatively different in several
respects, for instance in fiber length and vessel element diameter. The cambium
is more conspicuously storied in Tetrameles than in Octomeles. The wood of Dad-
sea is different from that of the two monotypic tree genera in the family and is
similar to that of some other “woody herbs.” The secondary phloem regions of
Octomeles and Tetrameles are strikingly similar in the zone of functional sieve
tube elements, but the amount and distribution of sclerenchyma in the zone of
sieve tube obliteration are different.

INTRODUCTION

Lindley in 1846 suggested a relationship between Datisca and Begonia based
on his knowledge of little more than the obvious morphological features, and even
a detailed study of floral and vegetative parts by the present writer (Davidson 1973)
permitted only an educated guess about the systematic position of the Datiscaceae
and the closeness of interfamilial ties. Many of the same trends and features are
present in Datiscaceae and Begoniaceae and in Flacourtiaceae, e.g., tendency
toward an inferior ovary, monoecy and dioecy, separate stigmas, capsular fruits,
numerous anatropous ovules and seeds, inflorescences with many flowers, ten-
dency toward anemophilv, valvate sepals, and nectar glands between gynoecium
and androecium; but it is the plasticity of just such traditionally reliable character-
istics in conjunction with the small size of the two families Datiscaceae and Begon-
iaceae that has made placement difficult, and not simply a lack of basic information.

xReview Committee for this Contribution
S. Carlquist
B. G. Cumbie
D. R. Reynolds
W. L. Sterne
R. F. Thorne

2Curator of Botany, Natural History Museum of Los Angeles County, 900 Exposition Blvd.,
Los Angeles, California 90007.

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The four species of the Datiscaceae are trees or root perennials. Datisca
cannabina L., a root perennial, has a range extending from the Middle East through
Iran and Afghanistan and into Nepal. This species was not available for study,
and therefore the California species, D. glomerata (Presl) Baill., which sometimes
develops a small amount of wood, was used. Octomeles sumatrana Miq. and Tet-
rameles nudiflora R. Br. are monotypic genera of Indo-Malesian trees attaining
heights of 150 to 180 feet. The former grows in rain forest and the latter in mon-
soon forest. Both trees are dioecious, a phenomenon explained (Davidson 1973)
as a response to selection for maximum outbreeding in essentially insular situa-
tions; and this explanation could also account for dioecy in D. cannabina and
androdioecy in D. glomerata.

In the present study, wood and phloem anatomy are compared among the
three genera. Ontogeny of the xylem is analyzed, and comparison is made of the
morphological variation in tracheary elements, fibers, and rays from primary to
secondary xylem in each genus to see if a basic pattern is present despite the dif-
ference in habit between Datisca and the two trees. This search has not been entirely
unrewarding, but interpretations based on this sort of data must be made with res-
ervation because of the lack of comparable information from larger families that
might be used to establish trends or at least the range of variation in a single group.
Data derived from measurements of wood elements of Octomeles and Tetrameles
are presented graphically to show size changes from the centers of the trees out-
ward toward the cambia.

MATERIALS AND METHODS

Samples of Datisca glomerata were collected in Southern California (David-
son 1002). Wood samples of Octomeles and Tetrameles were collected during a
field trip to Malasia in 1970. Collection data for Octomeles is as follows: David-
son 1124, sapling, Gum Gum Forest Reserve, Sabah; Davidson 1126, seedling
from Lungmanis grown in shade, Sabah; Davidson 1482, tree from Oomsis Cr.,
near Port Moresby, New Guinea. Data for Tetrameles: Davidson 1413a, tree from
Pahang, W. Malaysia; Davidson 1493, tree from Brown River, Papua. Wood sam-
ples were taken across the diameter of the bole at a level just above the buttresses,
at mid-point 30 to 60 ft above the ground, and at a level below the first branching.
Samples from buttresses, limbs, and twigs were also included. Woods were kiln-
dried and shipped to the U.S. with paraformaldehyde flake as a preservative. Cam-
bia, phloem tissues, and twigs were preserved in alcohol.

All material was prepared by standard microtechnical procedures. Woods of
the two trees sectioned poorly on the sliding microtome and had to be embedded
in Parowax. Phloem was stained with safranin-fast green and with lacmoid, fol-
lowing the procedure of Cheadle et al. (1953). Fiber measurements were taken
from macerations, but vessel elements were too large to macerate well and had to
be studied in tangential sections. All figures represent the average of 50 measure-
ments, except where stated otherwise.

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3

OBSERVATIONS
Octomeles sumatrana Miq.

Xylem. — Fusiform cambial initials from the base of the New Guinea tree
used in this study are storied, although the rows are not always perfectly even (Fig.
12). Cambial initials from the seedling and the four-meter sapling are not storied.
Ray initials are storied, as are the vessel elements, though in the latter case this
is inconspicuous because the vessels are solitary or paired; however, growth and
adjustments related to it obscure storying in the rest of the wood elements. Aver-
age fusiform initial length and tangential width are 470 /jl and 24 /jl , respectively
Corresponding values for ray initials are 780 n and 110 /x. In the shade-grown seed-
ling (Davidson 1126) the average size of fusiform initials is 250 /jl long and 8 /jl wide.

The following observations on primary xylem are based on serial radial sec-
tions and macerations of the xylem of seedling and sapling stems of Octomeles.
Secondary xylem consisting mostly of libriform fibers arises from the cambium
only a few centimeters proximal to the apex, apparently before stem elongation
is completed; therefore, it is difficult to distinguish between early secondary ele-
ments and the late metaxylem. For convenience an arbitrary topographic boundary
is used here. The first elements to arise from the interfascicular parts of the cambium
are very long libriform fibers, and therefore, all elements included within the fiber
zone opposite the original bundles are considered secondary. An ontogenetic study
in depth has not been attempted, and the terms “proto-” and “metaxylem” are
avoided. Instead, reference is made to the topographic relationships of the elements
discussed as seen in radial sections and in incompletely macerated groups.

Tracheary elements of the primary xylem have annular and helical thickenings.
The type of thickening may vary within a single element; and single, double, mul-
tiple, and singly-double helices are present in the peripheral part of the bundles
(using the terminology of Bierhorst 1960). Perforation plates of the helically thick-
ened elements may be simple (Fig. 1), or they may have a few thin bars.

Elements occurring in radial series adjust to the helically thickened vessel
members have scalariform pitting with broad or narrow bars on all faces (Fig. 3).
The helical thickenings of the preceding vessels are usually very closely spaced,
and the gyres are nearly transverse (Fig. 2). Adjacent to the scalariformly pitted
vessel elements are elements with alternate, closely spaced intervascular pits with
wide borders and elliptical to narrow inner apertures; or there may be a series of
transitional forms with more widely spaced bordered pits and larger apertures.
Vessel-parenchyma pitting varies in this transitional region from scalariform with
wide, horizontal bars to scalariform with thin, diagonal or variously oriented con-
nections between the larger bars. These elements may be part of the late metaxylem
or early secondary xylem. In vessel elements with closely spaced, alternate inter-
vascular pits, the pits opposite parenchyma cells are unilaterally compound and
half- bordered, and they are similar in most ways to the vessel-parenchyma pitting
in the mature xylem at a greater distance from the pith. The chief difference is that
the ray parenchyma near the pith consists mostly of upright cells, and the pits on

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the vessels are thus arranged in vertical rows. The perforation plates of the scalari-
formly pitted elements are almost always transverse, or nearly so, as are those of
the first alternately pitted elements adjacent to them; and the ends of the elements
are frequently tailed. The maturation pattern described here for the seedling is sim-
ilar to that found in the xylem taken about two meters above the ground level in the
sapling ( Davidson 1124).

The transition from the scalariformly pitted vessel elements to the first long,
alternately pitted vessel elements and to the subsequent shorter, alternately pitted
elements takes place within one millimeter of the pith in the sapling. Only a few
measurements were possible, but they indicate that the helical elements are the
longest (660 /jl ; 20 measurements) and that scalariformly pitted elements and the
first alternately pitted types are similar in length (530 /jl and 550 /m, respectively; 15
measurements each). The average diameter for both of these together is 130 fx (50
measurements). The long, alternately pitted members differ in several ways from
the shorter ones found throughout the rest of the wood. The longer elements are
narrow and have ends that are slightly constricted toward the rim of the perfora-
tion plate. In addition, as already mentioned, the vessel-parenchyma pitting pattern
differs because of the vertical length of the axial parenchyma close to the pith.

Mature vessel elements are short with wide lumina and simple, transverse
perforation plates and very thin walls (Fig. 13). Some elements have very large
tails. Intervascular pitting is alternate, and the pits are crowded so that the cham-
bers may appear slightly polygonal in face view (Fig. 19). Pit apertures are narrowly
elliptical to slit-like and are oriented at a slightly oblique angle to the vessel axis.
Pitting between vessel elements and axial parenchyma is half-bordered and unilat-
erally compound (Fig. 14). The border is on the vessel side, and up to eight vessel
pits may be opposite a single parenchyma pit field. Often, however, there are sev-
eral very fine, thickened bars extending across the parenchyma pit field, as well as
similar bars in the membrane of the vessel element pit. The pit apertures are ex-
tremely irregular in shape and may be elliptical, reniform, or lenticular, with narrow,
tapered ends (cf. Tetrameles, Fig. 26). When a single vessel pit is opposite a single
pit field, the width of the pit field in any direction is usually slightly less than that
of the pit membrane of the vessel pit. Occasionally pits to axial parenchyma cells
are very small, round, and widely spaced (Fig. 13); this type of pitting can be found
on radial and tangential walls but is apparently more common on the latter. Ves-
sels are rarely in direct contact with procumbent ray cells, but in such instances the
vessel member pits are similar to the intervascular pits, i.e., the apertures are narrow
and the chambers are crowded together. These pits are arranged in conspicuous
radial rows, however (Fig. 15). Transitions exist from this kind of pitting to that
described for vessel walls in contact with axial parenchyma, just as there are transi-
tions from axial parenchyma to procumbent ray cells. Both types can be found
opposite a single parenchyma cell. Tyloses are present in varying numbers in heart-
wood and sapwood, but they are no more common in the former than in the latter.
They are, however, very common (in 12 to 20 percent of the vessels) within a few
millimeters of the pith. Pits on tylosis walls are simple and very small.

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Figures in the following discussion represent the average of 50 measurements.
There is hardly any change in vessel element length and width along a 45 cm radius
from near the pith to the cambium. Along this radius element width varies from
220 /it to 330 with a subtle increase radially; and vessel element length (includ-
ing tails) fluctuates from 430 /jl to 520 \x, with no radial correlation. Vessels may
be solitary or in pairs. Near the pith up to half of them are in pairs, but along the
rest of the diameter frequency varies from 10 to 25 percent. These data are sum-
marized in figures 7 and 9. In transection vessel members are elliptical, with the
long axis radially directed (Fig. 17). The vertical course of vessels is usually straight
(Fig. 18), but it may be slightly sinuous.

Axial parenchyma is paratracheal vasicentric and forms a sheath two or more
cells thick (Fig. 17). The cells adjacent to the vessel element, forming the inner
strands, are very flat in transections and are square or broadly rectangular in face
view (Figs. 14, 16). The strand ends are truncated. These cells may be divided by
vertical or oblique walls as well as by the transverse walls formed in the original
cambial derivatives. The number of cells in the inner strands varies from four to 16
but is generally around six; and in the outer strands, from two to four. Length of
the strands varies from 500 /jl to 600 /jl. Although the inner strands have the greater
numbers of cells, they are shorter than the outer strands and are the same length as
the vessel elements. This is true regardless of the distance from the pith. Cells of
the outer strands obviously intergrade with the libriform fibers.

Libriform fiber length increases from 800 fx near the pith to 1300 /x at five
centimeters and then to 1700 fx at the outer end of the radius (Fig. 7). Fiber diam-
eter increases from 35 fx near the pith to 50 /x at five centimeters and then decreases
regularly to 30 /x at the end of the radius (Fig. 8). Morphologically the fibers can
be divided into three zones: the two long, tapering ends and the central “body”
having a nearly uniform lumen width throughout and comprising one half to one
third of the total length. Pits are confined to the radial walls. The narrowly elliptical
to very narrow, slitlike apertures of the simple pits are vertically oriented, and the
very thin walls tend to fracture along the pit apertures in macerations. Gelatinous
fibers are present in diffuse to concentrated, tangentially arranged groups (Fig. 17).
Septae are infrequent in both types of libriform fibers and even in the wood of seed-
lings. Fibers adjacent to rays have broader lumina than normal, and those differ-
entiating from fusiform initials that have “intruded” within a ray or between two
rays are especially broad and are often rectangular in transection.

In the wood seen in this study, no apotracheal diffuse parenchyma is present,
although it has been reported in some cases (Burgess 1966). The last source also
mentions that the wood may be distinctly ring porous, but no cases of ring porous-
ness were seen here.

Rays may be uniseriate or multiseriate (Fig. 18). Multiseriate rays are hetero-
cellular (Fig. 20). Near the pith only 11 percent of the rays in this sample are uni-
seriate, and along the remainder of the radius they comprise from two to 15 percent
of the total (Fig. 9). Neither abundance nor height of the uniseriate rays shows any
distinct correlation with distance from the pith, but there are definite peaks in the

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abundance that may correspond to ontogenetic changes in the cambium. More work
is necessary for a reliable demonstration of these changes. Multiseriate rays vary
from 1400 jjl high close to the pith to 1200 /x at the periphery of the bole, and the
total range of variation is from 900 /jl to 1400 /x. Again there is no correlation of
this with position on the radius (Fig. 7). Width of the multiseriate rays, however,
increases smoothly from 30 /jl at the center to 100 /x at the periphery (Fig. 8).

Uniseriate rays are composed of erect cells only, and near the pith, of course,
multiseriate rays are also composed of erect and square cells only. A few milli-
meters from the pith erect cells are found only at the margins of multiseriate rays,
and they vary from narrow and upright to rather broad in radial sections. The maxi-
mum height of erect cells observed is about 100 fx. The average for all those mea-
sured (150) is 72 /jl. Rays initials reaching the maximum apparently divide trans-
versely and two rows of square or even slightly procumbent cells thus result. The
several perfect radial sections seen show this change clearly. Changes in erect cells
on one margin tend to parallel changes in those on the other margin. Whether the
submarginal cells of the two-celled wing change ontogenetically to procumbent
cells or to erect cells could not be determined. Height of the marginal cells after
the division is from 40 to 50 /jl. The rays may have very long wings of erect cells,
and up to three multiseriate rays may be connected by uniseriate wings. The total
height then often exceeds 3 mm. Wings and rays connected by wings are much
more abundant in the inner part of the wood, e.g., wings were present on 25 per-
cent of the rays near the pith in this sample, but none was seen in sections from the
periphery of the bole. In other words, ray structure becomes simpler in a radial
direction from the pith toward the cambium.

Phloem. — Sieve tube elements of Octomeles are arranged singly or in groups
much like those of Tetrameles (see Fig. 28). They have simple to compound sieve
plates and thick, nacreous walls (Fig. 21). Simple sieve plates are always trans-
verse, but not all transverse plates are simple; compound ones are generally oblique,
with two to ten sieve areas. The four to twenty-one companion cells are very narrow
and deeply staining with fast green- safranin. In transections they are usually tri-
angular and are easily distinguishable from the ordinary phloem parenchyma cells,
which are slightly smaller in transectional area than the sieve tube elements and
are highly vacuolate. Slime plug material in sieve tube elements is present on sieve
areas opposite the lateral primary pit fields of the companion cells but not opposite
those of the parenchyma cells. These lateral pit fields are elliptical to irregularly
ovate, often with thin bars across the field, and thus they have a scalariform appear-
ance. Pits between sieve tube elements and phloem ray cells are similar. Neither
phloem parenchyma nor companion cells have nacreous walls, and both remain
in chains in macerations. Cells of the phloem parenchyma strands may divide trans-
versely, longitudinally, or obliquely.

Non-functional sieve tube elements are occluded by tylosoids (Fig. 22, on the
right). These arise as expansions of the protoplast of a companion cell into the
lumen of a sieve tube element, with a corresponding displacement of the nacreous
wall of the latter. Frequently several arise from adjacent companion cells, and

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where they meet in the lumen, the cell faces are flat; otherwise, they are spheroidal
to elongate. Soon after initial development, most of them acquire thick, lignified
walls, as do the corresponding companion cells. Companion cells that do not give
rise to tylosoids are still recognizable and apparently do not enlarge. Tylosoids
may contain anisotropic crystals and spherites (see Metcalfe and Chalk 1950, p. 700,
for a short account of this latter type of inclusion). Pits on and between the tylosoids
are simple. Ultimately the entire lumen of a sieve tube element may be occluded
by these structures or only a part of it, the rest being crushed by general expansion
of the ground tissue.

Secondary phloem fibers and strands of brachysclereids occur in bundles that
are tangentially elongate between the phloem rays and are rectangular in transec-
tion. In young stems the bundles are frequently radially directed as seen in transec-
tion because the rays are so much closer together. This sclerenchyma develops
directly from cambial derivatives, and not through sclerification of non-functional
sieve tube elements. The phloem fibers are very narrow and elongate, septate,
and frequently mucilaginous. Their lumina are almost completely occluded, either
by the mucilaginous walls or by lignified walls. Sclerenchyma in the bundles is
frequently transitional between simple brachysclereids and elongate fibers; i.e.,
brachysclereids may have very narrow, elongate tails attached to a short, cylindrical
body. These latter are transitional to short fibers that do not show a morphological
zonation and have simple, circular pits. The long phloem fibers have slit-like pits
that are oriented parallel to the long axis of each cell.

Phloem rays differ slightly from xylem rays. Derivatives of the erect ray ini-
tials divide transversely and all the phloem ray cells are thus procumbent, although
there is much less radial elongation of these cells than in the xylem rays (Fig. 24).

Dilatation of the rays occurs in the same zone of the phloem tissue in which the
tylosoids develop and comes about by both tangential elongation of and divisions
in the ray cells (Figs. 22-23). No obvious dilatation meristem is present. Axial
phloem parenchyma may divide, but ordinarily it takes little part in the expansion
process. Conspicuous intercellular spaces are present in the ray tissue once it begins
to expand, and the cells may contain starch, anisotropic crystals, and spherites.
Nests of brachysclereids and solitary short-armed sclereids develop in the widen-
ing rays, especially adjacent to the strands of secondary phloem fibers. The sclereid
nests may extend in either a tangential or a radial direction. The outer layer of pro-
cumbent ray cells in contact with the fiber strands is thus obscured (Fig. 23). Some-
times the axial phloem parenchyma strands sclerify, but this is uncommon.

Cambial initials from the cambium of the New Guinea tree used in this study
are twice as long as those from the shade-grown seedling. The initials from just
above the buttress level average 470 /x long and 24 /x in tangential width. In the
seedling stem they average 240 /x and 250 /x long in two different regions of the
cambium sampled, and 8 fx wide in a tangential direction. At the level of the but-
tresses, the sieve tube elements average 500 /x long in both macerated prepara-
tions and in tangential sections, and the average longest diameter is 84 /x. Their
length corresponds to that of the cambial initials (also cf. vessel element length).

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In the seedling the average sieve tube element length is 160 /jl, or almost 100 fx less
than that of the cambial initials, and the average longest diameter is 15 /x. This dif-
ference can be explained if some of the cambial derivatives divide transversely,
or almost so, and the daughter cells undergo only slight elongation. Secondary
phloem fibers in the bole from the same level as the sieve tube elements have an
average length of 1600 /x and an average diameter of 40 /x, values corresponding to
the dimensions of the libriform fibers in the outer xylem at that level (cf. Fig. 7).
Cambial initials in a small branch about 2 cm in diameter average 352 /x long. The
average length of the sieve tube elements in this stem is 307 ix, and the average
diameter is 31 /x\ phloem fibers average 1360 /x long and 29 fx in diameter. In this
case the difference between the length of the initials and that of the mature elements
possibly results in part from the measurement of slightly elongate derivatives. As
mentioned before, the cambium of the small branches is non-storied and is difficult
to locate precisely, unlike the storied cambium of the bole. The length of both ele-
ments of the phloem here are much shorter than those at the base of the tree. In the
seedling two to six companion cells accompany each element, with an average of
four. In the phloem at the base of the tree, an average of eight is found, and the
most seen was 21.

Tetrameles nudiflora R. Br.

Xylem. — Fusiform cambial initials from the base of the tree from Papua are
distinctly storied, as are the ray initials (Fig. 25). Fusiform initials from small
branches are not storied. Story ing is maintained in all elements of the wood includ-
ing the rays, but it is not obvious in the vessel elements because they are generally
solitary. Initials from the base of the tree have an average length of 520 fx and an
average tangential width of 13 fx .

Primary xylem of Tetrameles shows a transitional series in wall thickenings
slightly different from that in Octomeles. Annular thickenings are present in the
earliest formed tracheary elements, but there are also elements with irregularly
spiralled bands of very uneven thickness. Regular helical thickenings are single,
double, or a combination of each. Complexity of the branching and anastomosis
and tightness of the coils increases in a radial direction (Fig. 6). Thin connecting
sheets of wall material sometimes unite the gyres of the helices of the morpholog-
ically more advanced elements, and vessel elements with scalariform-to-altemate
pitting may be found directly adjacent to them (Fig. 4). Transitions in a compar-
able region in Octomeles are usually more abrupt, and vessel elements such as that
on the far right in figure 6 are not present in macerations of the xylem of the latter.
Often vessel elements with this scalariform-to-altemate pitting have a much greater
diameter than the helically thickened elements, and the bars between the pits are
very thin. The pits themselves may be hexagonal or polygonal in face view, which
is an indication that the elements have been slightly stretched, according to Bier-
horst and Zamora (1965). The pitting can be described as scalariform-reticulate in
this case. Perforation plates are nearly always simple and vary from transverse to
barely oblique, even on opposite ends of the same element (Fig. 5). Transitions

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9

from scalariform-to-alternate (scalariform-reticulate) pitted elements to mature,
alternately pitted elements occur over a very short radial distance. The same sort of
intermediate vessel members are present here as in comparable regions in Octomeles
(i.e., comparable in terms of the radial sequence of secondary wall types). The
intermediate vessel members are long with ends that are slightly constricted toward
the perforation plates, and the pitting is almost identical to that seen in Octomeles.

The large, morphologically mature vessel elements are almost indistinguishable
from those of Octomeles (Fig. 26). Intervascular pits are alternate and crowded
closely together; vessel-axial parenchyma pits are unilaterally compound and half-
bordered and have ovoid to lenticular or irregularly shaped chambers on the vessel
element side. Perforation plates are simple and transverse, and the rim is very narrow.
Inner apertures of intervascular pits are sometimes confluent by minute grooves,
especially toward the ends of the elements, and very large tails may be present
(Fig. 32). Pitting is less common on tangential walls, except when the vessels are
in radial pairs; but occasionally normal vessel-parenchyma pit pairs are present on
all faces. Vessel element to ray pitting is similar to that between vessels. Short radial
files of very small vessel elements are infrequently present among the very large
ones throughout the wood (Fig. 29, upper left). Pitting on these is similar to that
on the large elements. No such small vessels are present in the wood of Octomeles.
Lignified tyloses are common in heartwood and sapwood and have very large,
simple pits. In transection vessel elements are circular to elliptical with the major
axis oriented in a radial direction (Fig. 29), and the course of the vessels is straight
to slightly sinuous.

Figures given represent the average of 50 elements measured. Measurements
were taken at approximately six centimeter intervals along a 30 cm radius in a sec-
tion of wood from just above the buttress level of the tree from Papua. Vessel ele-
ments of Tetrameles are similar in length to those of Octomeles but are slightly
narrower. Vessel diameter increases hardly at all, as was the case in Octomeles, and
the change in vessel element length is negligible (Fig. 33). Vessels are solitary or
paired, with the pairs of vessels being a little more common than in Octomeles but
still accounting for only ten to 25 percent of the total (Fig. 1 1). The number of ves-
sels in a unit area, in this case 0.25 cm2, decreases in a radial direction (Fig. 34).

Axial parenchyma is paratracheal, as in Octomeles, but the inner and outer
strands are both storied and are the same length as the vessel elements (Fig. 30).
Strands are mostly two to six cells long, and those nearest the rays are rounded in
transection, more like the fibers, rather than tangentially flattened as they are in the
rest of the sheath. The thin-walled tissue that appears in transection to be para-
tracheal, aliform parenchyma is actually composed of fibers, as seen from serial
radial sections. Parenchyma is strictly vasicentric in the woods examined here. Axial
parenchyma often contains large starch grains.

Libriform fibers increase in length from 910 /jl near the pith to 1330 /jl at the
end of the radius 30 cm away (Fig. 33). Fluctuations in fiber diameter show no cor-
relation with fiber length (Fig. 35). The fibers are similar in appearance to those of
Octomeles, but the pits vary from slit-like and inconspicuous to large, with more

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noticeable pit membranes (Fig. 32). They show the same tendency to fracture along
the pit lines, and the pits are confined to the radial walls. Gelatinous fibers occur
in large, tangentially arranged groups, interspersed, of course, with the vessels.

Rays are uniseriate or multiseriate, and the latter are heterocellular (Figs. 30,
31), except near the pith, where the cells are square and erect only. The abundance
of uniseriate rays varies from seven to 20 percent and shows no correlation with
distance from the pith. There is a peak in abundance in the 18 to 24 cm region
(Fig. 10). Multiseriate rays are 1200 /jl high near the pith, 620 /z at 6 cm, and
690 fji at 30 cm (Fig. 33). The lowest multiseriate rays are only four cells high. Ray
width remains fairly constant along the radius (Fig. 35). Near the pith multiseriate
rays are composed almost entirely of erect and square cells, but the ontogenetic
change to procumbent cells takes place over a very short distance. Erect sheath
cells are rarely present. Uniseriate rays contain square and erect cells only, as seen
in radial sections. Frequently a ray consists of two or three multiseriate regions
connected by uniseriate wings. These “compound rays” are very numerous toward
the pith and decrease in abundance in a radial direction. Wings on rays are also less
common in the peripheral wood than near the pith, as was seen in Octomeles.

Phloem. — The appearance of the phloem zone with functional sieve-tube
elements in Tetrameles is similar to that in Octomeles. Sieve-tube elements from
the base of the tree from Papua (at the same level from which the xylem was taken)
are distinctly storied and have thick, nacreous walls (Fig. 27). Sieve plates are trans-
verse or slightly oblique and are either simple or compound. Most oblique sieve
plates have two to four sieve areas. Pitting of the phloem elements is similar to
that in Octomeles, and the arrangement of the elements in transection is the same.
Companion cells average 12 in a strand, with a range from 7 to 17. Sometimes two
rows of them accompany a single sieve-tube element, and the cells are occasionally
divided longitudinally or obliquely. Ordinary phloem parenchyma strands are much
larger in transectional area, though not longer than companion cell rows and con-
tain four to eight cells. Sieve-tube elements contain very small starch grains, and
the large parenchyma cells contain larger starch grains. Tylosoids are not present,
but instead the sieve tubes are obliterated by a general expansion of the phloem
parenchyma. Sieve plates, however, are still detectable in a transverse orientation
far into the old phloem.

Secondary phloem fibers differentiate directly from cambial derivatives and
are arranged in groups between the phloem rays (Fig. 28). The regular rectangular
shape seen in transections of Octomeles phloem is absent, and small cells of axial
and ray parenchyma adjacent to the fiber strands sclerify on their inner and radial
walls only, forming what are sometimes referred to as “hippocrepiform’’ sclereids.
These cells frequently contain large, cuboidal crystals, and they give the phloem
in longisection a distinctive appearance quite different from that of Octomeles,
where the adjacent cells are sclerified on all faces. The phloem fibers are usually
septate or gelatinous or both.

Phloem rays are non-storied and are similar to those in Octomeles (Fig. 27).
Expansion of the rays occurs in the zone of non-functional sieve-tube elements.

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Ray cells adjacent to the fiber bundles sclerify, but large sclereid nests similar to
those in Octomeles are infrequent. In general sclerification in the outer phloem
region of the bole is not as pronounced as in Octomeles.

Cambial initials at the base of the tree have an average length of 520 /x and an
average tangential width of 15 /jl . Sieve-tube elements at the same level are 480 /jl
long and 65 /jl on the longest diameter. Phloem fibers average 1230 /. x long and 43 /x
in diameter. Cambial initials from a young branch have an average length of
400 /jl and an average tangential width of 12 /jl. The average length of sieve-tube
elements is 400 /x and the average greatest width, 49 /jl;, corresponding sizes for
the phloem fibers in the young stem are 940 /jl in length and 19 /jl in diameter. Once
again the phloem fibers are similar in length to the xylem fibers in the part of the
wood closest to the phloem cambium.

Datisca glomerata

Xylem. — In the primary xylem of Datisca, a series of secondary wall thicken-
ing types similar to that in the other two genera is present. Annular and helical thick-
enings and scalariform pitting occur in vessel elements seen in radial sections arid in
macerations. The gyres of the helices are more frequently branched and tightly
wound in vessel elements that are adjacent to elements with scalariform pitting.
The transitional series from helical thickening to scalariform pits to alternate pits
on intervascular walls is much less abrupt in Datisca than in Octomeles and Tetra-
meles because a considerable number of elongate pits and scalariformly pitted areas
occur on the earliest alternately pitted vessel members. These areas of scalariform
pitting are not necessarily localized at the ends of the elements toward the perfora-
tion plates, where the pitting of most vessel elements is frequently modified or
distorted, but may occur anywhere on the intervascular face. In stems with a half
inch of wood or more, vessel elements near the cambium have mostly alternate
intervascular pits, with only a few elongate pits (Fig. 36). Intervascular pits may
be widely spaced, but commonly they are very crowded, with chambers that are
polygonal in face view and with inner apertures that are ovate to elliptical. The ves-
sels may be arranged in distinct concentric bands or in more or less distinct diag-
onal bands that intergrade into a diffuse arrangement of vessels in different parts
of the same stem.

Axial parenchyma is paratracheal in one or two layers, or around some vessels
it is scanty. It is very difficult to recognize in transections because of the thick,
lignified walls. The cells are often vertically elongate, and the half-bordered vessel-
parenchyma pitting is thus more conspicuously scalariform than in Octomeles and
Tetrameles. These pits are sometimes unilaterally compound. In places where a vessel
is close to a ray, the axial parenchyma tends to be flatter and more nearly rectangular
in transection, and the vessel-parenchyma pitting is almost identical to that in the
two tree genera.

Libriform fibers are short and non-septate and have large, simple pits that are
slit-like to elliptical with large, elliptical pit membranes. In some stems gelatinous
fibers are absent, but in others they are far more common than non-gelatinous ones.

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Rays are uniseriate or multiseriate (Fig. 38). Multiseriate rays are homocellular
with erect and square cells in the first 7 mm of wood, but in the outer wood in thick
stems there is a tendency for the central cells of the ray to be square and procum-
bent only. Pits in the tangential walls of procumbent and erect cells are tiny but
numerous. Pits on the transverse or radial walls are much larger.

The average length of vessel elements is 200 /jl, and the average greatest width,
96 /jl. These measurements are taken from the outer xylem of a stem with 7 mm of
wood (Davidson 1002). Libriform fibers are 430 /jl long and 14 /jl in diameter. The
average height of multiseriate rays is 520 /jl, and the average width, 40 /. x. In a dif-
ferent stem from the same collection, this time with only 3 mm of wood, the average
length of vessel elements is 240 /jl, and the average greatest width, 12 /jl. Libriform
fibers in this stem have an average length of 420 /jl and an average diameter of
23 /jl; and the average height of multiseriate rays is 570 /jl, and the average width,
45 /jl.

Phloem. — Sieve-tube elements have thin, nacreous walls and transverse to
slightly oblique sieve plates. Sieve plates are almost invariably simple. Very short-
sieve-tube elements have a single companion cell, but the usual number is four. As
in Octomeles and Tetrameles, sieve-tube elements are occasionally solitary in tran-
sections, but more often they are in irregular groups or radial rows, and they are
generally larger in transverse section than the surrounding phloem parenchyma.
The average length of sieve-tube elements is 180 /jl, and the average greatest width
is 53 /jl. Secondary phloem fibers are absent. Dilatation of the rays occurs in the
outer phloem where the sieve tubes are nonfunctional, and transections show large
“wedges” of dilated ray tissue.

Cambial initials of Datisca glomerata are short and show a tendency toward
story ing (Fig. 39). The average length of the initials is 200 /jl, and the average
tangential width is 10/. x.

SUMMARY AND CONCLUSIONS

Woods of Octomeles and Tetrameles are rather similar in appearance and in
physical properties. They are light-weight and nondurable and perish rapidly after
attacks of fungi and beetles. When dry, they are very weak under most stresses.
They have proved useful, therefore, in the manufacture of coffins, match sticks,
dugout canoes, tea chests, and carved wooden ware (Burgess 1966; Desch 1941).
Anatomically they are very specialized, consisting only of large vessel elements
with simple perforation plates, thin- walled libriform fibers, axial parenchyma re-
stricted to two paratracheal layers, and rays. The libriform fibers have very wide
lumina and narrow, tapering ends; and they fracture in a nearly vertical direction
in macerations, indicating a corresponding alignment or orientation of the cellulose
fibrils in the wall. This is possibly a specialization for vertical strength, and a pre-
sumed lack of lateral strength resulting from the thin walls of the elements is then
compensated by wall hydration. A reasonable assumption is that the wood is some-
what stronger in the living condition than when cut and “green” or dry, and that

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the rapid growth of these trees (at least of Octomeles ) is correlated with this method
(wall hydration in the libriform fibers) of attaining strength rather than one involving
the production of thick, lignified fiber walls. Zones of gelatinous fibers in the wood
are possibly also involved in this function.

The individual elements are similar not only in morphology but also in size.
Vessel elements tend to be slightly smaller in radial diameter, however, in Tetra-
meles than in Octomeles , and libriform fibers of the former tend to be shorter. Also,
vessels in Tetrameles are more frequently in radial pairs. The tendency for vessels
to be in oblique rows in transections of Tetrameles wood mentioned by Lakhanpal
and Verma (1965) was not evident in the woods in this study. Trends in the altera-
tion of length and diameter of vessel elements and libriform fibers from the pith
toward the exteriors of the boles of the two trees are similar. The most conspicuous
difference is the greater amount of story ing in Tetrameles. All elements of the sec-
ondary xylem are storied, including the libriform fibers, a feature that would appear
to require a uniform and coordinated increase in the length of the fibers during the
increase in girth of the trees. Support for this can be seen in figure 33, which shows a
smooth increase compared to that in Octomeles (Fig. 7).

Cambial initials of Datisca average 200 p in length and are less than half as
long as those at the base of the bole in Tetrameles (520 p) and Octomeles (470 /x).
Carlquist (1966b) found the same relationship in Compositae: cambial initial length
for all caudex perennials studied was half (152 p) that of the trees (312 /x). Cumbie
and Mertz (1963) found in Sophora a decreasing conspicuousness of storying in
sequence from trees to subshrubs to herbaceous perennials, a situation similar to
that in Datiscaceae. Cambia in Octomeles and Tetrameles are clearly storied, although
some regions in the cambium of Octomeles do not show this as well as others; how-
ever, the cambium of Datisca is not distinctly storied but shows instead a tendency
toward that condition, and the fusiform initials are short and similar to one another in
length, which is usually the case when obvious storying is present.

The cambium is storied in a wide variety of plants, and the occurrence of this
feature surely bears a relationship to habit and the amount of secondary growth that
takes place, as pointed out by Cumbie and Merz (1963) and Carlquist (1966b). In
Octomeles the shortest fusiform cambial initials are in seedlings (250 /x ), the largest
are in the cambium from the base of mature trees (470 p), and intermediate sized
initials are in twigs (352 fx ). In this case the initials elongate considerably over
seedling size, but an increasingly evident storied structure in this same sequence
results from presumed radial longitudinal divisions. In twigs from a mature tree
the vessel elements decrease in size from helical and scalariform (660 /x) to oppositely
pitted elements (530 p to 550 /x), and this apparently reflects a similar change in
the fusiform initials.

Scarcity of data on cell lengths in actual storied cambia force one for the most
part to extrapolate from vessel element lengths. When compared to published data
from both vessel element and cambial initial lengths, these values for Datiscaceae
do not appear to be unusual. The length for Octomeles is slightly larger than that
given for Hibiscus tiliaceus L. (400 fx ) and Picraena excelsa Lindl. (also 400 p)
(Beijer 1927); and that for Datisca glomerata is within the range for plants of

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comparable habit (90-200 /x) given by Beijer (1927) and close to that of Hibiscus
lasiocarpus Cav. (210-212 p ) (Cumbie 1963). Webber (1934) gives the range for ves-
sel element lengths in her material of Hibiscus tiliaceus as 59 to 456 /x (mostly 287 /jl).
Vessel element lengths are given by Hyde (1925) for the following tropical trees
with light-weight woods: Heliocarpus appendiculata Turcz., 462 /x; Apeiba aspera
Aubl., 510 /x; Pachira barrigon Seem., 280 /x; Cavanillesia platanifolia HBK.,
675 /x; Wercklea insignis Pitt. & Standi., 300-600 /x; and Cordia heterophylla Poir.,
276 /x.

Among the Senecioneae, 62 percent of the species studied by Carlquist (1962)
had storied wood structure, and in these vessel element length varied from 463 /x
in Liabum klattii Rob. & Greenm. and 445 /x in Gynoxys hallii Hieron. to 114 p
in Tetradymia argyraea Munz & Roos. The species of Tetradymia, all occupying a
desert habitat, had the shortest vessel elements, and the diminution of elements in
xerophytes is well documented in Compositae (Carlquist 1966b). Trees have the
longest and caudex perennials, the shortest vessel elements, on the average, among
the habit types found. in this family. Only six percent of the annuals or biennials
employed in this study had storied structure; however, 50 percent of each of the
other habit categories, i.e., caudex perennial, shrub or subshrub, tree, and rosette
tree or rosette shrub, had it.

From the extensive data of Carlquist (1960, 1962, 1965, 1966a) one can con-
clude that the degree of expression of storying in the wood is not necessarily related
to the length of vessel elements (and hence, cambial initials). In the Astereae (Carl-
quist 1960) species with short fibers show storying more clearly than species with
longer fibers, but storying is not always concerned with the amount of fiber elonga-
tion, but instead with the kind of elongation: differentially intrusive or coordinated.
This can be seen clearly in Tetrameles, in which storying extends through all ele-
ments of the wood despite the considerable length of these elements. Presumably
there is an upper limit above which the radial longitudinal divisions necessary for
the formation and maintenance of a storied cambium are no longer feasible. This
limit is obviously above 510 /x.

The trends of change in wood element sizes from the pith outward are inter-
esting to note. Vessel element length remains almost unchanged in both trees
throughout the 30 to 45 cm radii examined. In each case vessel element width
increases slightly. A similar relationship is present in Sophora (Cumbie and Mertz
1963). In contrast fiber length increases 1.6 and 1.8 times the length of the cambial
initials close to the pith in Octomeles and Tetrameles, respectively, and reaches a
maximum of 2.1 and 3.8 times initial length at the ends of the radii. According to
the table of Chattaway (1936) one might expect an enlargement of 2.0 to 2.3 times
the size of the initials for species with initials between 450 p and 500 p long. The
smaller amount of enlargement and the more uniform increase in length of the
fibers in Tetrameles compared to Octomeles is no doubt at least partly responsible
for the persistence of the storied condition in the wood. Fiber diameter in Octomeles
decreases after a brief increase, but in Tetrameles no clear correlation with increasing
girth is present. Height of multiseriate rays doubles in Octomeles but remains
unchanged in Tetrameles. Changes in the percentages of uniseriate rays and vessel

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pairs present and in uniseriate and multiseriate ray height show subtle peaks and
valleys on the graphs that are possibly correlated with environmental changes,
especially because the peaks and valleys occur at similar distances from the pith
(e.g., at 10 to 15 cm and 25 to 30 cm in Octomeles; and at 18 to 24 cm in Tetra-
meles). The number of vessel pairs in Va cm2 as seen in transection decreases
greatly. Ray width in mm and fiber diameter show hardly any change except for
the slight peaks at 18 to 24 cm in Tetrameles, but ray width in Octomeles increases
dramatically.

The woods of Octomeles and Tetrameles, although similar in appearance and
gross morphology, are thus quantitatively different in numerous respects. The wood
of Datisca differs both quantitatively and qualitatively from that of the two trees,
but this does not necessarily support the recognition of two families, Datiscaceae
and Tetramelaceae, as was done by Airy Shaw (1965). Datisca produces much
less xylem and the mature wood pattern is much more slowly attained; thus one
might expect little obvious correspondence between wood of herbaceous and arbo-
reous members of the same family, as is the case here. The earliest secondary xylem
in a stem of Datisca is, in fact, unlike that in the bole or even in twigs of Octomeles
and Tetrameles. On the other hand, one might expect that if enough wood were
eventually produced in plants with delayed maturation, a pattern resembling that
found in trees of the same family would result. The outer wood produced in the
largest stems of Datisca used in this study definitely has a configuration different
from that close to the pith: rays contain a greater abundance of procumbent cells,
intervascular pitting is alternate with only a very few transversely elongate pits,
axial parenchyma is more conspicuously paratracheal, and the dimorphism in pitting
between intervascular walls and vessel element-axial parenchyma walls is more
pronounced.

A conspicuous difference in the wood of Datisca, however, is the arrangement
of vessels in concentric or tangential bands. As far as can be determined, these bands
do not correspond to growth rings. The vessel elements within the tangential group-
ings are all of approximately the same diameter, and the regions between bands are
chiefly devoid of vessels; furthermore, definite concentric zones in which fiber
diameter increases or decreases are not found either associated with the vessel group-
ings or in the zones between them. This feature of the xylem represents a major
difference that can not be easily explained as simply the result of seasonality of the
habitat. Tetrameles has been reported as occasionally having ring porous wood,
although in the present study ring porousness was seen only in buttresses. An addi-
tional study of the buttress wood in Tetrameles is in progress.

Thus despite the difference in habits and the amount of wood produced, some
correspondence between the woods of Datisca and the two Indo-Malesian genera
can be noted; this is in addition to the storying or tendency toward it mentioned
above.

A specimen of a fossil wood has been described by Lakhanpal and Verma
(1965) and is tentatively included in the Datiscaceae as Tetrameleoxylon prenudi-
flora. It is from the Deccan Intertrappean beds near Nagpur in Central India and
is possibly as old as early Eocene. As described and pictured, its anatomy approaches

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very closely that of Tetrameles, and the storied structure of the fossil is especially
interesting. Storying of all wood elements is very uncommon (S. Carlquist, per-
sonal communication, 1972). However, several authors (Bailey 1924; Bancroft
1932) have pointed out some of the difficulties in identifying fossil woods and the
treacherous convergences of xylem characteristics that may occur (Bailey 1957).
In the 1957 paper Bailey stressed the importance of corroborative evidence in mak-
ing statements about relationships even among living plants.

The anatomical and morphological characteristics of Datiscaceae indicate a
fairly secure phylogenetic relationship with the Flacourtiaceae (Davidson 1973).
The features of the xylem allow a modest refinement of this view. The level of
specialization of the xylem in Octomeles and Tetrameles is greater than that in all
Flacourtiaceae investigated so far. Values for the libriform fiber/vessel element
ratio given by Miller (1975) are predominately below two. The values for Datisca-
ceae are: Octomeles, 3.95; Tetrameles, 2.77; and Datisca, 2.15. Vessel elements in
Flacourtiaceae are smaller in diameter and in many species tend to be more angular
in transection than in Datiscaceae. Fiber-tracheids are present in many species in
addition to libriform fibers, and these elements generally have thick walls and nar-
row lumina.

Axial parenchyma is absent in secondary xylem of Flacourtiaceae and is absent
or scanty in members of several other families considered to be related within the
suborder Cistineae, and for which there is data: Cistaceae (Metcalfe and Chalk 1950),
Violaceae (Taylor 1972), and Scyphostegiaceae (Metcalfe 1956). In these three
families axial parenchyma, when present, is paratracheal as a few cells about the
vessel elements. In Datiscaceae axial parenchyma is regularly paratracheal in two
rows in Octomeles and Tetrameles; and in Datisca it is scanty or absent. Presence
of abundant apotracheal axial parenchyma in Paropsia and Soyauxia indicates the
possibility of an early and independent specialization in the xylem (preceding the
subsequent and more obvious habit-related specializations) in Thorne’s (1968)
Caricineae because the tribe Paropsieae (Passifloraceae) is considered a morpho-
logically unspecialized group in transitional between Flacourtiaceae and Passiflora-
ceae (Ayensu and Stern 1964). A similar early specialization in the wood of Dati-
scaceae related to rapid growth is a possible consideration independent of the status
of the proposed fossil Tetrameleoxylon.

Secondary phloem regions of Octomeles and Tetrameles bear a striking resem-
blance to one another in the zone of functional sieve tube elements. In each genus
the sieve tube elements have nearly the same average length (500 p) and diameter
(ca 70 p) and have transverse and simple or slightly oblique and compound sieve
plates. In addition the lateral walls thicken greatly, apparently as an artifact upon
treatment with the fixative, and stain pearly green with fast green. The lumina of
the sieve tubes may be almost completely occluded by these walls. Anatomists
have referred to them as “nacreous” walls, and their presence appears to be a fairly
common feature in the phloem (Esau 1969). Uncommon or infrequently reported,
however, is the presence of a large number of companion cells in a single strand
accompanying each sieve tube element. In Octomeles and Tetrameles up to 15 and
even 20 may be present opposite a sieve tube element, and they are easily dis-

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tinguishable from the other phloem elements in tangential, radial, and transverse
sections. Secondary phloem fibers differentiate within the part of the phloem con-
taining functional sieve tube elements. After dilation of the phloem rays has begun,
the sieve tubes in Octomeles are “invaded” by tylosoids that grow out of the com-
panion cells; however, tylosoids are lacking in the phloem of Tetrameles, in which
the sieve tube elements are obliterated by general expansion of the phloem paren-
chyma. Moreover, the sclerenchyma that forms around the secondary phloem fibers
in this region in Tetrameles is composed of “hippocrepiform” sclereids, i.e., they
are horseshoe-shaped in transections because the outer cell walls remain unsclerified.
Sclereids in a comparable region in Octomeles are sclerified on all faces. This is
only a minor distinction between the two, but in longisection the outer phloem of
each is easily distinguishable because of it.

In Datisca secondary phloem fibers are absent, a common feature of herbaceous
plants, and the number of companion cells is four to five. Nacreous walls are
present, but they are not nearly as thick as in the other two genera; and the sieve
plates are almost exclusively simple.

Evidence from anatomy and morphology supports the inclusion of these three
genera in a single family. Subfamilial taxonomic ranking is possibly more a matter
of personal preference here, but the present writer believes that the differences
between Datisceae ( Datisca ) and Tetrameleae ( Tetrameles and Octomeles ) do not
necessitate subfamily status for the two groups; rather, they are better treated as
tribes, as was done by Warburg (1895) and Gilg (1925).

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Figures 1-6. Primary and early secondary xylem elements, all from macerations. Figures 1-3.
Octomeles sumatrana. Davidson 1127. Figures 4-6. Tetrameles nudiflora. Davidson 1413a.
Drawn with camera lucida. Figure 1. Simple perforation plate on a vessel element with helical
thickenings, x 1200. Figure 2. Vessel element. Very closely spaced gyres with complicated
branchings, x 600. Figure 3. Two adjacent vessels, one with narrow, scalariform pits. Actual
contact between these two elements was obscured, x 600. Figure 4. Two adjacent vessel
elements. Note three thin connecting walls between the gyres. Parenchyma was present be-
tween the two elements, x 1200. Figure 5. Simple perforation plate. Note branches in the
helix and one thickening band that ends blindly. X 1200. Figure 6. Four adjacent elements,
each with a progressively more complex thickening pattern. Stippling indicates the wall is
more lightly stained than the dark bands. X 1200.

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10

0 5

25 45 CM

Figures 7-11. Graphs showing average lengths and percentages of certain xylem elements
(ordinate) in relation to distance from the pith (abscissa) in cm. FD, fiber diameter; FL, fiber
length; RH, ray height; RW, ray width; UR, uniseriate rays; URH, uniseriate ray height; VL,
vessel element length; VW, longest width of vessel element; VP. vessel elements in pairs.
Figures 7-9. Octomeles sumatrana. Davidson 1482. Figures 10-11. Tetrameles nudiflora.
Davidson 1493. Figure 7. Note that fiber length increases but vessel element length changes
very little. Figure 8. Fiber diameter decreases; width of multiseriate rays increases. Figure 9.
Note rough correspondence of peaks between the percentages of uniseriate rays and vessel
elements in pairs. Figure 10. Abundance of uniseriate rays shows a peak. Figure 11. Per-
centage of vessel elements in pairs decreases.

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Figures 12-16. Octomeles sumatrana. Davidson 1482. Figures 13-16 from secondary xylem.
Figure 12. Cambium. Storied condition is most evident on the right. Cambial derivatives are
on the far left, x 45. Figure 13. Vessel element, flattened by the cover slip. Note unusually
small vessel-parenchyma pits, x 155. Figure 14. Vessel-to-axial parenchyma pitting. These
pits are half-bordered and unilaterally compound, x 560. Figure 15. Vessel pits opposite pro-
cumbent ray cells. X 155. Figure 16. Very long strand of axial parenchyma consisting of six-
teen cells. Strand is directly adjacent to the vessel element. X 155.

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Figures 17-20. Secondary xylem of Octomeles sumatrana. Davidson 1482. Figure 17. Tran-
section. Darkened patches are gelatinous fibers, x 40. Figure 18. Tangential section. X 40.
Figure 19. Intervascular pitting. From a tangential section, x 360. Figure 20. Radial section.
Note erect cells at the top of the ray. x 40.

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Figures 21-24. Phloem of Octomeles sumatrana. Davidson 1482. Figure 21. Transection of
four sieve tubes, three with oblique sieve plates and one with a transverse sieve plate. Note
appearance of the nacreous walls. X 920. Figure 22. Tangential section through several phloem
rays, three of which are undergoing dilation. Secondary phloem fibers are in strands to left
of center. Sieve tube elements occluded by tylosoids are to the right, x 60. Figure 23. Trans-
verse section showing dilation of a phloem ray and the strands of secondary phloem fibers, x 60.
Figure 24. Radial section through a phloem ray showing mostly procumbent cells on the left.
Cambium is on the left, out of the picture, x 60.

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Figures 25-28. Tetrameles nudiflora. Figures 25-26. Davidson 1493. Figures 27-28. David-
son 1413. Figure 25. Tangential section of cambium region showing storied cambium. Cam-
bial derivatives are on the far left, x 70. Figure 26. Vessel element from secondary xylem.
Note lenticular pits opposite axial parenchyma cells, x 250. Figure 27. Tangential section
of the secondary phloem showing storied sieve tube elements, x 80. Figure 28. Transverse
section of the secondary phloem. Note sieve tube elements with nacreous walls and second-
ary phloem fibers. Cambium is to the left. X 105.

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Figures 29-32. Secondary xylem of Tetrameles nudiflora. Davidson 1493. Figure 29.
Transection, x 40. Figure 30. Tangential section. Note storied fibers and axial parenchyma,
x 45. Figure 31. Radial section, x 52. Figure 32. Vessel element with a large tail and a few
libriform fibers from a maceration. X 70.

NO. V/ 0.25 CM

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2E

o

o

o

o

o

o

m

o

o

Figures 33-35. Tetrameles nudiflora. Davidson 1493. Graphs showing average xylem component measurements and number of vessel elements (ordinate)
in relation to distance from the pith (abscissa). Symbols are the same as in Figures 7-11. Figure 33. Note that fiber length increases, vessel element length
and diameter hardly change. Figure 34. The number of vessel elements in a unit of area decreases greatly. Figure 35. Fiber diameter and multiseriate ray
width change little.

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Figures 36-39. Datisca glomerata. Davidson 1002. Figure 36. Intervascular pitting. From
a tangential section of secondary xylem. Note simple perforation plate, x 340. Figure 37.
Transection of secondary xylem showing the ring porous condition in a stem with a centi-
meter of wood. Pith is toward the right, x 55. Figure 38. Tangential section of secondary
xylem. x 60. Figure 39. Tangential section of stem with one centimeter of wood, showing
cambium. Note tendency toward storying of very short fusiform initials, x 110.

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LITERATURE CITED

Airy Shaw, H. K. 1965. Diagnoses of new families, new names, etc., for the seventh
edition of Willis’s ‘Dictionary.’ Kew Bull. 18:249-273.

Ayensu, E. S. and W. L. Stern. 1964. Systematic anatomy and ontogeny of the stem in the
Passifloraceae. Contr. U.S. Nat. Herb. 34:45-73.

Bailey, I. W. 1924. The problem of identifying the wood of Cretacious and later dicotyledons:
Paraphyllanthoxylon arizonense. Ann. Bot. (London) 38:439-451.

1957. The potentialities and limitations of wood anatomy in the study of the

phylogeny and classification of Angiosperms. J. Arnold Arbor. 38:243-254.

Bancroft, H. 1932. On the identification of isolated timber specimens with especial reference
to fossil woods. Ann. Bot. (London) 46:353-365.

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Accepted for publication February 12, 1976.

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