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TULAWS STUDIES 
Iv ZOOLOGY 


VOLUME 2 
1964-1965 


TULANE UNIVERSITY 
NEW ORLEANS 


TULANE STUDIES IN ZOOLOGY is devoted primarily to the zoology of the waters 
and adjacent land areas of the Gulf of Mexico and the Caribbean Sea. Each number is 
issued separately and contains an individual monographic study, or several minor studies. 
As volumes are completed, title pages and tables of contents are distributed to institu- 
tions receiving the entire series. 


Manuscripts submitted for publication are evaluated by the editor or associate editor and 
by an editorial committee selected for each paper. Contributors need not be members 
of the Tulane University faculty. 


The editors of Talane Studies in Zoology recommend conformance with the principles 
stated in chapters I and II (only) of the Style Manual for Biological Journals, 2nd ed., 
published in 1964 by the American Institute of Biological Sciences, Washington, D. C. 


Manuscripts should be submitted on good paper, as original typewritten copy, double- 
spaced, and carefully corrected. Two copies, carbon or other suitable reproduction, must 
accompany the original to expedite editing and assure more rapid publication. Legends 
for figures should be prepared on a separate page. Illustrations should be proportioned 
for one or two column width reproductions and should allow for insertion of legend if 
occupying a whole page. 


An abstract not exceeding three percent of the length of the original article must ac- 
company each manuscript submitted. This will be “transmitted to Biological Abstracts 
and any other abstracting journal specified by the writer. 


The editors also recognize the policy adopted by the Federal Council for Science and 
Technology, and endorsed by the Conference of Biological Editors, that page charges for 
publication of scientific research results in scientific journals will be budgeted for and 
paid as a necessary part of research costs under Federal grants and contracts. Accord- 
ingly, writers crediting research grant support in their contributions will be requested 
to defray publication costs if allowable under the terms of their specific awards. 


Illustrations and tabular matter in excess of 20 percent of the total number of pages may 
be charged to the author, the levy applied being the excess above 10-point typesetting 
costs. 


Exchanges are invited from institutions publishing comparable series but subscriptions 
are available if no exchange agreement can be effected. Separate numbers or volumes 
can be purchased by individuals, but subscriptions are not accepted. Remittance should 
accompany orders from individuals. Authors may obtain separates of their articles at cost. 


Address all communications concerning manuscripts and editorial matters to the editor; 
Communications concerning exchanges, and orders for individual numbers to the Meade 
Natural History Library. 


When citing this series authors are requested to use the following abbreviations: Tlane 
Stud. Zool. 


Price for this volume: $3.50. 


Harold A. Dundee, Edztor 
Gerald E. Gunning, Associate Editor 
Department of Biology, 
Tulane University, 
New Orleans, Louisiana 70118, U.S.A. 
Harold A. Dundee, Director 
Meade Natural History Library, James R. Reed, Jr. 
Tulane University, Assistant to the Editors 
New Orleans, Louisiana 70118, U.S.A. 


CONTENTS OF VOLUME 12 


NUMBER 


ile 


bo 


(J) 


A NEW BRANCHIOBDELLID (ANNELIDA) FROM COSTA RICA 
Perry C. Holt 


THE RIVER CRABS OF COSTA RICA, AND THE SUBFAMILIES OF 
THE PSEUDOTHELPHUSIDAH 


Alfr ed E. Galler 


MYSIDOPSIS ALMYRA, A NEW ESTUARINE MYSID CRUSTACEAN 
FROM LOUISIANA AND FLORIDA... 


ituomes E. ipomen 


AGE DETERMINATION OF THE COTTON RAT (SIGMODON HISPIDUS) 
Robert K. Chipman 


DIGENETIC TREMATODES OF MARINE FISHES FROM APALACHEE 
BAY, GULF OF MEXICO. 


“FusdiM. Nahhae and Robart Bo Short 


HISTOLOGY, DEVELOPMENT, AND INDIVIDUAL VARIATION OF COM- 
gg ee VI Fe ODE) EAC UA, Oe aos. 2 ee Se oe ee 


Andrew A. Ar he Norman C. Negus, and Martha Sapp Downs 


ETHEOSTOMA DITREMA, A NEW DARTER OF THE SUBGENUS OLIGO- 
CEPHALUS (PERCIDAE) FROM SPRINGS OF THE ALABAMA RIVER 
BASIN IN ALABAMA AND GEORGIA__ 


oun s. pameces Fal Ron D. Suttkus 


PARASITES FROM LOUISIANA CRAYFISHES_____ wae 
Fr sali Sorandar es- Bee mal 


A NEW SUBSPECIES OF THE CRAWFISH ORCONECTES LEPTOGO- 
NOPODUS FROM THE OUACHITA RIVER DRAINAGE IN ARKANSAS 


Jobe Mitzpatrick, J: 


ECOLOGICAL DISTRIBUTION AND ACTIVITY PERIODS OF BATS OF 
THE MOGOLLON MOUNTAINS AREA OF NEW MEXICO AND ADJA- 
SURI Maem NOLO) Are ee Se ee ee ee ee 


Clyde Tones 


ETHEOSTOMA (OLIGOCEPHALUS) NUCHALE, A NEW DARTER FROM 
AMON STONE: SP RENG-UN At AB A MAC 1.2) as eee eee 


William Mile: Howell aad Richard Dale Caldew ell 


EARLY DEVELOPMENTAL STAGES OF THE ROCK SHRIMP, SICYONIA 
BREVIROSTRIS STIMPSON, REARED IN THE LABORATORY. 


Harry L. Cook and M. Hee Mur Diy 


FISHES TAKEN IN MONTHLY TRAWL SAMPLES OFFSHORE OF PI- 
NELLAS COUNTY, FLORIDA, WITH NEW ADDITIONS TO THE FISH 
FAUNA OF THE TAMPA BAsYaeA Rin Ate a oe 


Martin A. Moe, Jr. ae Geonee T. Martin 


PAGE 


if 


39 


51 


87 


93 


101 


109 


129 


Printed in the U.S. 
at New Orleans, by 
HAUSER-AMERICAN: 


TULANE STUDIES 
IN ZOOLOGY 


Volume 12, Number 1 August 21, 1964 


A NEW BRANCHIOBDELLID (ANNELIDA) 
FROM COSTA RICA 


PERRY C. HOLT, 
DEPARTMENT OF BIOLOGY 
AND 
VIRGINIA AGRICULTURAL EXPERIMENT STATION, 
VIRGINIA POLYTECHNIC INSTITUTE, 
BLACKSBURG, VIRGINIA Pen 2 


THE RIVER CRABS OF COSTA RICA, AND THE SUBFAMILIES 
OF THE PSEUDOTHELPHUSIDAE 
ALFRED E. SMALLEY, 


DEPARTMENT OF ZOOLOGY, TULANE UNIVERSITY, 
NEW ORLEANS, LOUISIANA Dinca 


MYSIDOPSIS ALMYRA, A NEW ESTUARINE MYSID CRUSTACEAN 
FROM LOUISIANA AND FLORIDA 
THOMAS E. BOWMAN, 
DIVISION OF MARINE INVERTEBRATES, 


SMITHSONIAN INSTITUTION, 
WASHINGTON, D.C. 20560 p. 15 


TULANE UNIVERSITY 
NEW ORLEANS 


TULANE STUDIES IN ZOOLOGY is devoted primarily to the zoology of the waters 
and adjacent land areas of the Gulf of Mexico and the Caribbean Sea. Each number is 
issued separately and contains an individual monographic study, or several minor studies. As 
volumes are completed, title pages and tables of contents are distributed to institutions ex- 
changing the entire series. 


Manuscripts submitted for publication are evaluated by the editor or associate editor 
and by an editorial committee selected for each paper. Contributors need not be mem- 
bers of the Tulane University faculty. 


The editors of Tulane Studies tn Zoology recommend conformance with the principles 
stated in chapters I and II (only) of the Style Manual for Biological Journals published in 
1960 by the American Institute of Biological Sciences, Washington, D. C. 


The editors also recognize the policy adopted by the Federal Council for Science and Tech- 
nology, and endorsed by the Conference of Biological Editors, that page charges for publica- 
tion of scientific research results in scientific journals will be budgeted for and paid as a 
necessary part of research costs under Federal grants and contracts. Accordingly, writers 
crediting research grant support in their contributions will be requested to defray publica- 
tion costs if allowable under the terms of their specific awards. 


Illustrations and tabular matter in excess of 20 percent of the total number of pages may 
be charged to the author, the levy applied being the excess above 10-point typesetting costs. 


Manuscripts should be submitted on good paper, as original typewritten copy, double- | 
spaced, and carefully corrected. Two carbon copies in addition to the original will help 
expedite editing and assure more rapid publication. 


An abstract not exceeding three percent of the length of the original article must accom- 
pany each manuscript submitted. This will be transmitted to Biological Abstracts and any 
other abstracting journal specified by the writer. 


Separate numbers or volumes may be purchased by individuals, but subscriptions are not 
accepted. Remittance should accompany orders from individuals. Authors may obtain 
copies for personal use at cost. 


Address all communications concerning manuscripts and editorial matters to the editor; 
communications concerning exchanges, and orders for individual numbers to the Director, 
Meade Natural History Library. 


When citing this series authors are requested to use the following abbreviations: Tulane 
Stud. Zool. 


Price for this number: $0.50. 


Harold A. Dundee, Editor 

Gerald E. Gunning, Associate Editor 
Department of Zoology, 

Tulane University, 

New Orleans, Louisiana 70118, U.S.A. 


Royal D. Suttkus, Director 

’ Meade Natural History Library, Francis L. Rose, 
Tulane University, Assistant to the Editors 
New Orleans, Louisiana 70118, U.S.A. 


TULANE STUDIES IN ZOOLOGY 


Volume ie Number 1 


“August De 1964 


A NEW BRANCHIOBDELLID (ANNELIDA ) 
FROM COSTA RICA 


PERRY C. HOLT, 
Department of Biology 
and 
Virginia Agricultural Experiment Station, 
Virginia Polytechnic Institute, 
Blacksburg, Virginta 


ABSTRACT 


A new branchiobdellid, Cambarincola 
smalleyi, from freshwater crabs of the 
family Pseudothelphusidae in Costa Ri- 
ca is described. A somewhat primitive 
member of the genus, this species is 
assumed to be a southern survivor of 
a Pleistocene migration of cambarine 
crawfishes and their epizoic commen- 
sals. It is hypothesized that the bran- 
chiobdellids survived in Costa Rica by 
passing from their former hests to the 
winners of the interglacial or  post- 
Pleistocene competition between craw- 
fishes and crabs. 


Branchiobdellid annelid worms, usually 
found as epizoic commensals on freshwater 
crawfishes of the family Astacidae, have 
been known from Mexico for some time 
(Rioje, 1940, 1943). They recently have 
been recorded from hosts other than astacid 
crawfishes (Hobbs and Villalobos F., 1958; 
Holt, 1963). The finding of them on fresh- 
water crabs of the family Pseudothelphusidae 
in Costa Rica by Alfred E. Smalley of Tulane 
University, is, nonetheless, worthy of note. 
First, this discovery adds another to the 
rapidly increasing list of crustacean families 
which serve as hosts for the branchiobdellids. 
In addition, the southward extension of their 
range from the Isthmus of Tehuantepec in 
Mexico through approximately seven degrees 


of latitude to the highlands of Costa Rica is 
of some zoogeographical interest. 


I am grateful to Dr. Smalley for making 
the four mature worms which he recovered 
from specimens of Psewdothelphusa tumt- 
manus Rathbun ( Pseudothelphusidae ) ayail- 
able to me for study and take pleasure in 
naming the new species of the genus Cam- 
barincola which they represent in his honor. 


The procedures I use in the study of 
branchiobdellids have been described else- 
where (Holt, 1960). My studies are sup- 
ported by a grant, NSF-GB372, from the 
National Science Foundation. 


Cambarincola smalleyi, n. sp. 
( Figs. 1-4) 

Diagnosis. Medium-sized members of the 
genus; head, approximately equal in diame- 
ter to that of segment I and the sucker, 
showing external evidence of being com- 
posed of four segments; prosomites of body 
segments not appreciably greater in diameter 
than metasomites; jaws homodont and iso- 
morphic, dental formula 6/6. Male repro- 
ductive system: the prostate about two-thirds 
the size of the spermiducal gland in length 
and diameter and histologically different 
from the latter, the prostate lacking an ental 


EDITORIAL COMMITTEE FOR THIS PAPER: 


G. E. GATES, Emeritus Professor and Visiting Professor, University of Maine, Orono, 


Maine 


WALTER J. HARMAN, Chairman, Department of Zoology, Louisiana State University, 


Baton Rouge, Louisiana 


WILLIAM R. MuRCHIE, Professor of Zoology, Flint College, University of Michigan, 


Flint, Michigan 


i) 


bulb; the spermiducal gland without defer- 
ent lobes; the bursa elongate pyriform in 
shape. Female reproductive system: sperma- 
theca with a long ectal duct and an ental 
process. 

Description, Since only four specimens of 
Cambarincola smalleyi are known, measure- 
ments are of little value. The type speci- 
men, however, as some indication of the size 
of these animals, has the following dimen- 
sions: total length, 2.82 mm, head length, 
0.43 mm; head diameter, 0.29 mm; diame- 
ter, segment I, 0.40 mm; diameter, segment 
VI, O51 mm; diameter, sucker, 0.39 mm. 
The smallest specimen is 1.93 mm long. 

The worms are somewhat corpulent in 
appearance; the greatest diameter of the 
holotype is one-sixth the total body length. 
The prosomites are not markedly greater in 
diameter than the metasomites, the body 
wall lacking the supernumerary muscles 
which produce this condition in some bran- 
chiobdellids. The sucker is of usual appear- 
ance and somewhat greater in diameter than 
the head or segment I. 

The head shows obvious external signs of 
being composed of four segments (Fig. 1). 
Other branchiobdellids are known to have 
four vascular commissures in the head, but 
in C. smalleyi these commissures are readily 
apparent in the specimens mounted entire. 
The peristomium is, as usual, divided into 
dorsal and ventral “lips”; each lip is sub- 
divided by a slight median emargination. 
No oral papillae are present. 

The jaws (Figs, 2 and 3) are unusual. 
The upper and lower jaws are similar in size 
and shape and the number of teeth (six) is 
the same for each jaw. The teeth, further- 
more, are subequal in size and their points 
form a gently curved arc in dorsal view. 
The jaws are sub-rectangular in dorsal view. 
They contrast, then, in these respects, with 
the triangular jaws with fewer teeth of most 
species of the genus. The dental formula of 
6/6 is diagnostic of C. smalleyi. 

The anterior nephridiopore, located as 
usual for the genus, is unusually prominent. 
The “bladder” and outlet duct formed by 
the junction of the two nephridia are thick- 
walled and glandular in appearance. Whether 
or not this reflects a real difference or the 
accidents of preservation cannot be deter- 
mined from the material available. 

The prostate is composed of large vacuo- 
lated glandular cells, the spermiducal gland 


Tulane Studies 1n Zoology 


Vol. 12 


anterior 


es 


025mm Fig-2 


ei 


025mm _. 
Fig-3 


Figures 1-3. Cambarincola smalleyi, n. sp. 
1. Outline drawing of type specimen. 2. Dor- 
sal jaw, paratype. 3. Ventral jaw, paratype. 


of more densely granular cells, but the pros- 
tatic ental bulb is absent. The short, rela- 
tively thick, differentiated prostate without 
an ental bulb, a condition not described for 
any other branchiobdellid, is characteristic 
of C. smalleyz, 

The spermiducal gland is perhaps some- 
what smaller in proportion to the total size 
of the animal than in most other species of 
the genus, but otherwise is not remarkable. 
The same statement can be made about the 
other organs of the male reproductive sys- 
tem. 

A clitellum is present on segments VI and 
XI. The spermatheca has a rather long 
ectal duct and the spermathecal bulb has a 
small, but distinct, ental process (Fig. 4). 

Type locality. Rio Hondura, eight miles 
north of San Jeronimo de Moravia, San 
Jose Province, Costa Rica. 

Host. Pseudothelphusa tumimanus Rath- 
bun. 

Disposition of types. The holotype, U. S. 
N. M. No. 30940 and one paratype, U. S. 
N. M. No. 30941 are deposited in the col- 
lections of the Division of Marine Inverte- 
brates, United States National Museum. One 
paratype is in the collection of Dr. Smalley 
at Tulane University and the remaining one 
is retained in my collections kept at the Vir- 
ginia Polytechnic Institute (PCH 1702). 

Distribution. Cambartncola smalleyi is 
known only from the type locality. 


No. 1 


Remarks. Cambarincola smalleyi most 
closely resembles C. vitrea Ellis, 1919, in jaw 
structure but differs in the larger number 
of teeth borne by the jaws of the former 
and in the fact that the same number of teeth 
is present on each jaw. The general body 
form is like that of many species of the 
genus, differing in the more obvious signs 
of segmentation of the head. The male re- 
productive system in the histologically dif- 
ferentiated prostate is like that of Hoffman’s 
(1963) phtladelphica section of the genus, 
which includes C. vitrea, but differs in the 
absence of a prostatic bulb. One can specu- 
late that C. smalleyi is related in a greater 
or lesser degree to C. vitrea, a species which 
is widespread in the mid-continental plains 
region of the United States, or to C. meso- 
chorea Hoffman, 1963, likewise a mid- 
continental species. C. mesochorea has an 
undifferentiated prostate without an ental 
bulb, but has an ental spermathecal process, 
present in C. smalleyi and absent in C. vitrea. 

Cambarincola smalleyi extends the known 
range of branchiobdellids almost 500 miles 
southward from southern Mexico to Costa 
Rica. Presumably it represents a montane 
survivor of a population representing the 
pre-Pleistocene North American fauna which 
moved southward during one of the Pleisto- 
cene glaciations. The species must have 
reached Costa Rica more recently than the 
late Miocene or early Pliocene closing of the 
Central American water gaps, if these gaps 
existed as is generally believed. The north- 
ern, temperate distribution of branchiob- 
dellids would argue against them being a 
part of the Neotropical Cenozoic fauna of 
North America. 

Though the jaws of C. smalleyi are pres- 
ently thought to reflect a primitive bran- 
chiobdellid condition (Ellis, 1919) and the 
segmentation of the head is undoubtedly 
primitive, the species does not appear mark- 
edly primitive in other respects. The most 
reasonable conclusion would seem to be that 
it is a descendant of an already relative- 
ly advanced cambarincolid, pre-Pleistocene 
stock intermediate between Cambarincola 
mesochorea and C. vitrea. 

Finally, some notice must be taken of the 
host of C. smalleyi, Presently, branchiob- 
dellids are known from astacine, cambaroi- 
dine, and cambarine crawfishes, isopods of 
the genus Asellus (Holt, 1963), and grapsid 
crabs (Hobbs and Villalobos F., 1958). 


New Branchtobdellid 


Wo 


anterior 


aos 


ventral 


Fig 4 


-OSmm 


Figure 4. Cambarincola smalleyi, lateral 
view of reproductive systems of type speci- 
men. Abbreviations: 6, bursa; ed, ejacula- 
tory duct; enp, ental process of spermathe- 
ca; pr, prostate; sb, bulb of spermatheca; 
sd, ectal duct of spermatheca; spg, spermi- 
ducal gland; vd, vas deferens. 


Their occurrence on the tropical, freshwater, 
pseudothelphusid crabs takes them consider- 
ably beyond the range of the cambarine 
crawfishes which reach their southern limits 
in the Guatemalan highlands. Unquestion- 
ably, branchiobdellids are primarily com- 
mensals of astacid decapods, but no longer 
can be assumed to be confined to these hosts. 
Yet cambarine crawfishes must have carried 
them to Costa Rica, lost in competition with 
the tropical crabs, and passed their com- 
mensals to their conquerors. 


The hypothesis that the branchiobdellids 
passed from crawfishes to crabs in southern 
Mexico and hence by repeated transfers and 
migrations southward to other crabs in Costa 
Rica may be, on the contrary, the correct ex- 
planation: it seems to me less likely. 


Summary. A new branchiobdellid, Cam- 
barincola smalleyi, from freshwater crabs of 
the family Pseudothelphusidae in Costa Rica 
is described. Although a somewhat primitive 
member of the genus, it is not markedly so, 
and is assumed to be a southern survivor of 
a Pleistocene migration of cambarine craw- 
fishes and their epizoic commensals. The 
branchiobdellids presumably survived in 


4 Tulane Studies n Zoology 


Costa Rica by passing from their former 
hosts to the winners of the interglacial or 
post-Pleistocene competition between craw- 
fishes and crabs. 


REFERENCES CITED 


Evuis, Max M. 1919. The branchiobdellid 
worms in the collections of the United 
States National Museum, with descrip- 
tions of new genera and new species, 
Proc. U. S. Nat. Mus. ; 241-265. 

Hopss, Horton H., JR. a. ALEJANDRO VIL- 
LALOBOS F. 1958. The exoskeleton of a 
freshwater crab as a microhabitat for 
several invertebrates. Virginia J. Sci. 
(N. S.) 9: 395-396. 

HorrMaN, RICHARD L. 1963. A revision of 
the North American annelid worms of 
the genus Cambarincola (Oligochaeta: 
Branchiobdellidae). Proc. U. S. Nat. Mus. 
aI SS PAPAS Zale 


Vol, 12 


Hout, Perry C. 1949. A comparative study 
of the reproductive systems of NXironogi- 
ton instabilius instabilius (Moore) and 
Cambarincola philadelphica (Leidy) (An- 
nelida, Oligochaeta, Brancniobdellidae), 
J. Morph. 84: 535-572. 

ia 1960. The genus Cerato- 
drilus Hall ‘(Branchiobde’ lidae, Oligochae- 
ta), with the description of a new species. 
Virginia Casals (ANS IS) ints GsiH7'7- 

Pe oe eee ee 1963. A new branchiob- 
dellid (Branchiobdellidae: Cambarinco- 
la). J. Tennessee Acad. Sci. 38: 97-100. 

RioJA, ENRIGUE, 1940. Estudios Hidrobi- 
ologicos II. Datos sobre los Branchiob- 
dellidae de Xochimileco, Zempoala y Tex- 
coco, Anales del Instituto de Biologia 11 
(1): 249-253. 

~ _........ 1948. Estudios Hidrobi- 
ologicos IX. Anotaciones sobre branquiob- 
delidos Mexicanos. Anales del Instituto 
de Biologia 14(2): 541-545. 


THE RIVER CRABS OF COSTA RICA, AND THE SUBFAMILIES 
OF THE PSEUDOTHELPHUSIDAE 
ALFRED E. SMALLEY, 
Department of Zoology, Tulane University, 
New Orleans, Louisiana 


ABSTRACT 


The Costa Rican river crabs of the 
family Pseudothelphusidae are reviewed 
and their gonopods described. Two sub- 
families are recognized in the family 
Pseudothelphusidae; the new subfami- 
ly Epilobocerinae for Hpilobocera, and 
Pseudothelphusinae for the remaining 
four genera. Epilobocera fuhrmanni is 
a Pseudothelphusa. New subgenera 
proposed for Pseudothelphusa are: Ach- 
lidon, for P. agrestis; Allacanthus, for 
P. pittieri; Megathelphusa, for P. mag- 
na and P. richmondi; Ptychophallus, 
for P. tristani, P. montana, P. tumi- 
manus, P. exilipes, and P. xantusi. P. 
convexa is relegated to the synonymy 
of P. montana, 


I. INTRODUCTION 


The American river crabs are an important 
component of the fauna of tropical fresh 
waters. There are numerous species, most of 
which have restricted ranges. Taxonomical- 
ly, the river crabs have been neglected in 
spite of the many interesting systematic and 
zoogeographic problems posed by them. 
Most of the Pseudothelphusidae were de- 
scribed by Rathbun, who also produced the 
most recent monograph of the family (Rath- 
bun, 1905). Since that time, studies have 
been sporadic, usually incidental to other 
research, or included in faunistic papers. 
Furthermore, earlier students did not recog- 
nize the importance of the male pleopods 
(gonopods) in classification. Rathbun was 
inconsistent in the use of gonopod char- 
acters. Sometimes she provided good figures, 
but at other times she ignored the gonopods, 
even when the description was based on a 
male. 


Rathbun was well aware of the inade- 
quacy of using the carapace for taxonomic 
distinctions in the genus Psewdothelphusa, 
and also realized the specific distinctiveness 
of the gonopods, but nevertheless chose to 
base her keys and descriptions on non- 
gonopodal features. As a result, many de- 
scriptions are based on females, although 
species of Pseudothelphusa should never be 
described from females alone. Even if a 
species can be distinguished without using 
the gonopods, its relationships to other spe- 
cies and genera will remain unknown if this 
practice is followed. 

In this paper, the five genera of the 
Pseudothelphusidae are divided into two sub- 
families and the Costa Rican Pseudothel- 
phusa into subgenera on the basis of gono- 
pod structure. In addition, supplementary 
descriptions are given for the Costa Rican 
species. 

There are types of all the Costa Rican 
species in the U. S. National Museum. 


II]. COLLECTION LOCALITIES 


Since most of the Pseudothelphusidae have 
restricted ranges, the localities where they 
are collected assume considerable impor- 
tance. All of the Pseudothelphusidae known 
from Costa Rica were described by Rath- 
bun (1893, 1896, 1898), from specimens 
provided by various collectors. The locality 
data supplied by these collectors are inade- 
quate, usually including the name of the 
nearest village or town and the altitude, but 
never the province. Since finding the lo- 
calities where these collections were made 


EDITORIAL COMMITTEE FOR THIS PAPER: 


FENNER A. CHACE, JR., Senior Scientist, Department of Zoology, United States Na- 


tional Museum, Washington, D.C. 


Dr. L. B. HoLttHuts, Rijksmuseum van Naturlijke Historie, Raamsteeg 2, Leiden, 


The Netherlands 


HAROLD E. VOKES, Professor and Chairman, Department of Geology, Tulane Uni- 


versity, New Orleans, Louisiana 


6 Tulane Studies n Zoology 


proved to be a difficult task, the results of 
my search are listed below. Sr. Don Salvador 
Jiménez-Canossa was most helpful in resolv- 
ing difficult problems. The gazetteer by 
Selander and Vaurie (1962) is very useful, 
and would have greatly lightened my task 
had it been available sooner. 

Aguabuena. Puntarenas Prov., near the 
Panamanian border, 8° 44’ N, 82° 56’ W. 


Boruca. Puntarenas Prov., 9° 01’ N, 83° 
PAW 

Cachi. CGartago Prov. 9° 49° N, 83° 
48’ W. 

Cariblanco. Heredia Prov., 10° 10’ N, 
84° 10’ W. 


Chemin de Carrillo. Junction of San José, 
Cartago, and Limon Provinces, 10° 10° N, 
83°57 W. 

El Coronel. Border of San José and Car- 
tago Provinces, on the Rio Sucio, 10° 7’ N, 
832 oo WE 


Java. Selander and Vaurie list a “Que- 
brada de Java,” Puntarenas Prov., 8° 52’ N, 
83° O17 W. 


La Palma. There are several “La Palmas” 
in Costa Rica. According to the altitude of 
1500 meters, the one cited by Rathbun is 
probably Alto La Palma, San José Prov., 
10° 03’ N, 83° 58’ W. 

Pacaca, Rodeo. Pacaca is an older name 
for Villa Colon: Rodeo is probably the name 
for a farm or ranch. San José Prov., 9° 56’ 
N, 84° 16’ W. 

Palmar. Palmar Norte or Palmar Sur, 
Puntarenas Prov., 8° 57’ N, 83° 27’ W. 

Pozo Azul. Guanacaste Prov., 10° 12’ N, 
84° 56’ W 

Rio Maria Aguilar. A tributary of the Rio 
Virilla, probably near the city of San José, 
San José Prov., 9° 56’ N, 84° 05’ W. 

Rio Torres. Also a tributary of the Rio 
Virilla, probably near San José (see previous 
item ). 

San Carlos. A region, or district, in Ala- 
juela Province, drained by the Rio San 
Carlos. 

Santa Clara Jiménez. Heredia Prov., 10° 
13’ N, 83° 43° W. 

Santa Domingo, Gulf of Dulce. 
renas Prov., 8° 32’ N, 83° 17’ W. 

Surubres, near San Mateo, Alajuela Prov., 
9° 56’ N, 84° 30° W. 

La Flor, Torito. Cartago Prov., 9° 53’ N, 
83° 50’ W. 


Punta- 


Vo 2 


Ill. KEY TO THE SPECIES OF COSTA RICAN 
PSEUDOTHELPHUSIDAE 


The following key is based principally on 
gonopod morphology. There are no funda- 
mental differences between the gonopods of 
Pseudothelphusa and Potamocarcinus, and 
the gonopod characteristics of Potamocarcin- 
ws included in the key should not be con- 
sidered of generic importance. Terminology 
follows Smalley (1964). 


1. Antero-lateral teeth of carapace 

large and spiniform; ventral 

border of front of carapace 

not visible from above; mar- 

ginal process of gonopod ex- 

tending beyond apex. 

Saige WOE Potamocarcinus nicaraguensis 
Antero-lateral teeth small or 

minute; ventral margin of 

front visible from above; 

marginal process of gonopod, 

when evident, not extending 

beyond apex. Pseudothelphu- 

$0) 22 wd ee 
Tip of gonopod not folded, api- 

cal spines pointing apically ; 

gonopod simple in structure. 

__Pseudothelphusa (Achlidon) agrestis 
Tip of gonopod folded; at least 

some of the apical spines 

pointing: cephalad === aaa 3 
Patch of well-defined, short, 

sub-apical spines on cephalic 

surface of gonopods, in addi- 

tion to apical spines. 

Pseudothelphusa (Allacanthus) pittieri 
Apical spines only, ey 4 
4. Large mesial tooth near apex 

of gonopod; shaft without 
broad lateral process. Sub- 
genus Megathelphusa 5 
Apical part of gonopod broad, 
joined to rest of gonopod by 
narrow peduncle; usually with 
broad lateral processes. Sub- 
genus Ptychophallus 
5. Marginal process of gonopod 
curving laterad, ending at 
tip of gonopod. 


bo 


Go 


pel er ee Pseudothelphusa magna 
Marginal process curving: mesi- 

ad, ending just short of tip 

of gonopod. 

ne ts BIE Pee, Pseudothelphusa richmondi 
6. Lateral subapical process of 

gonopod not broad, not ex- 

ceeding apical process; mesi- 

al process subapical. 

-Pseudothelphusa xantusi 

Lateral subapical process broad, 

exceeding apical process C7 
Mesial apical process of gono- 

pod broad, hatchet-shaped. 

= __Pseudothelphusa tristani 
Mesial’ apical process narrow, 

finger-like 


<I 


8. Lateral subapical process of 
eupeue not bilobed. 
Pseudothelphusa exilipes 


lateral subapical | process _ bi- 
lobed _ ie ie ae 9) 


9. Mesial apical process satae gono- 
pod, seen in marginal view, 
nearly as long as lateral api- 
cal process; proximal lobe of 
subapical process sub-acute. 
Small species. 
_Pseudothelphusa montana 


Mesial subapical process much 
shorter than lateral process; 
proximal lobe of subapical 
process broadly rounded. 
Large species. 

Pseudothelphusa tumimanus 


IV. SYSTEMATIC ACCOUNT 


Most of the specimens on which this ac- 
count is based were collected by me in Costa 
Rica during the summer of 1962, and were 
identified by comparison with types in the 
U.S. National Museum. Specimens from the 
U. S. National Museum are indicated by the 
initials USNM. The drawings of Epilobo- 
cera cubensis are from a specimen borrowed 
from the Museum of Comparative Anatomy, 
Harvard University. All other specimens 
are at Tulane University. 


Measurements, where given, are for great- 
est carapace width and median carapace 
length in millimeters, of the largest male 
examined. Immature males too small to be 
identified with certainty are simply included 
with the large males in the same collection 
and listed as “imm.”. Some question of 
identity applies to any female Psewdothel- 
phusa, and they also are grouped with the 
identified males. Specimens so small that 
the pleopods are not developed are desig- 
nated “imm.”. A number of collections did 
not include any identifiable specimens and 
are omitted. Figures in parentheses indicate 
the altitude in meters. Localities are in 
Costa Rica unless otherwise specified. 

Synonymies are given only if the species 
has been mentioned by anyone other than 
Rathbun (1896, 1898, 1905), and Young 
(1900). 


Pseudothelphusa tuberculata Rathbun is 
omitted from this account. There is a female 
from Boruca, in the U. S. National Museum, 
determined by Rathbun, but I believe that 
this is an erroneous identification, and that 
the range of P. tuberculata should be re- 
stricted to Guatemala. The same remarks 


Costa Rican River Crabs 7/ 


apply to a female Pseudothelphusa vene- 
zwelensis Rathbun from La Palma. 

In the illustrations of the gonopods, the 
caudal surface is always oriented so that the 
margin can be identified as a line extending 
the length of the gonopod, with a proximal 
tuft of setae. The cephalic surface is oriented 
so that at least some of the apical spines 
point directly toward the observer. In most 
Costa Rican species, the apical spines are 
directed cephalad, although this is not the 
case with many, if not most, Pseudothel- 
phusidae. Most gonopods are more or less 
flattened caudocephalad, but the drawings: 
of the caudal and cephalic surfaces are not 
necessarily at 180 degrees, so the gonopod 
may appear broader in one view than in the 
other. A standard orientation for gonopod 
drawings is desirable because figures of 
complex gonopods are difficult to compare 
if they are drawn from different sides. Best 
results are obtained if the right gonopod is 
removed from the crab for examination, and 
subsequently kept in a small cotton-stoppered 
vial in the jar with the crab. 


The Subfamilies of the Pseudothelphusidae 


Bott (1955) divided the old family Pota- 
monidae into the three families Potamonidae, 
Pseudothelphusidae, and Deckiniidae, and 
his arrangement is adopted here, although 
with some reservations. All the American 
river crabs, except the genus Trichodactylus 
Latreille, 1825, belong in the family Pseudo- 
thelphusidae, which is restricted to the New 
World. 


The relationships among the genera of 
the Pseudothelphusidae have undergone vari- 
Ous treatments in the past as summarized by 
Colosi (1920). Gonopod morphology has 
not been used in previous classifications at 
the generic level, even though some car- 
cinologists, notably Alcock (1910), Colosi 
(1920), and Bott (1955), have recognized 
the importance of the gonopods in distin- 
guishing the Pseudothelphusidae from other 
river crabs. The Pseudothelphusidae can be 
divided into two readily distinguishable sub- 
families on the basis of gonopod structure 
alone. 


Pseudothelphusinae Ortmann, 1893 


Pseudothelphusidae with gonopods armed 
at the tip with a group of apical spines, con- 
centrated in a distinct area at the aperture 
of the sperm channel. Type genus, Psemdo- 


8 Tulane Studies n Zoology 


thelphusa de Saussure, 1857. Other genera; 
Potamocarcinus WH. Milne-Edwards, 1853; 
Rathbunia Nobili, 1896, and Typhlopseudo- 
thelphusa Rioja, 1952. 


Epilobocerinae, new subfamily 


Pseudothelphusidae with gonopods armed 
at the tip with both a patch of apical spines 
at the aperture of the sperm channel, and 
also with large, scattered spines. Type and 
only genus, Epilobocera Stimpson, 1860. 

The difference between the gonopods of 
the two subfamilies can readily be seen by 
comparing Epilobocera cubensis Stimpson, 
1860 (Figs. 16-17) with any Pseudothel- 
phusa. Zimmer (1914) described a river 
crab from Columbia and placed it in Epzlo- 
bocera on the basis of non-gonopodal struc- 
tures. Fortunately, Zimmer provided good 
illustrations of the gonopod, which clearly 
show that Epilobocera fuhrmanni Zimmer 
should be Psewdothelphusa fuhrmanni (Zim- 
mer ). 


Genus Potamocarcinus H. Milne-Edwards 
1853 

Potamocarcinus ntcaraguensis Rathbun 

Rathbun, 1893, p. 656; Colosi, 1920, p. 
17; Smalley, 1964, p. 29. 

Specimens examined: Trinidad, Heredia 
Prov., border between Costa Rica and Nica- 
ragua; 1 May 1960; 2 @ 2.—Resguardo, 
Guanacaste Prov., near Nicaraguan border; 
7 Feb. 1960; 4 ¢ ¢. 

Margin of gonopod straight; caudal pro- 
cess prominent, extending well beyond apex; 
a prominent mesial apical tooth; two smaller, 
spiniform, cephalic teeth placed close to- 
gether; without lateral setae. 

This species can be distinguished in the 
field from all other Costa Rican Pseudo- 
thelphusidae by the prominent spiniform 
anterolateral teeth of the carapace. If I had 
only the gonopod before me, I would place 
this species in Psewdothelphusa (Megathel- 
phusa). A large species, found in lakes, 
rivers, and streams in Nicaragua and Costa 
Rica. Largest female examined by Rathbun, 
95 x 60.1; largest Tulane male, 75.1 x 45.1. 


Genus Pseudothelphusa de Saussure, 1857 


Rathbun made two subgeneric divisions 
of the large genus Pseudothelphusa, one 
based on gonopod structure (1898, p. 513), 
the other mostly on structure of the carapace, 


third maxillipeds, and chelae (1905, p. 27 


Volz 


ff.). The two arrangements result in dif- 
ferent classifications, but neither was formal- 
ly proposed, and there are at present no sub- 
genera recognized for Pseudothelphusa, 
Rathbun’s grouping according to gonopod 
structure is, in my Opinion, the more satis- 
factory of the two. A number of changes 
must be made in Rathbun’s gonopod groups, 
but for the Costa Rican Pseudothelphusa, 
only the following changes are necessary: 
(1) remove P. pittieri from Group 1, and 
erect for it a monotypic subgenus, (2) add 
P. extlipes to Group 2, and (3) remove 
P. agrestis from Group 6 and erect for it a 
monotypic subgenus. 


The phylogeny, evolution, and zoogeog- 
raphy of Pseudothelphusa cannot profitably 
be studied without a subgeneric classifica- 
tion, for which the most satisfactory criteria 
are gonopod characters. Subgenera are there- 
fore proposed for the Costa Rican Pseudo- 
thelphusa. Subgenera can similarly be 
erected for other species groups of Pseudo- 
thelphusa, but a large number of unresolved 
taxonomic problems prevent further exten- 
sion of the classification at this time. 


Achlidon, new subgenus 


Gonopod simple in structure, curving 
mesiad, with expanded apex. Blunt, mesial 
subapical tooth the only process. Apical 
spines directed apically, apex without folds. 
Margin curving mesiad, emerging near 
cephalic surface. Type and only species, P. 
agrestis. Achlidon (masc.)—unornamented. 


Pseudothelphusa ( Achlidon) agrestis 
Rathbun, 1898 


Specimens examined: La Flor, near Torito, 
Cartago Prov., 1 6,1 2, the types (USNM). 
Illustrated by Rathbun (1898, p. 515). 
The shape of the gonopod is quite different 
from the other species in Rathbun’s Group 6. 


Allacanthos, new subgenus 


Gonopod and margin straight, apex folded, 
sperm channel emerging on cephalic sur- 
face. With a blunt, mesial, apical lobe, and 
a small, sharp, apically directed lateral lobe 
bearing sparse apical spines. Cephalic and 
lateral surfaces with well defined area of 
small regularly spaced spines; row of scat- 
tered spines on mesial surface of shaft. Type 
and only species, P. pittiert. Allacanthos 
(fem. )—other spines. 


No. 1 


Pseudothelphusa ( Allacanthos) pittiert 
Rathbun, 1898 
( Figs. 1-3) 
Specimens examined: Agua Buena, Punta- 
renas Prov.; 2 ¢ 6,1 2, the types (USNM). 
A small species (19.1 x 11.9), with the 
characters of the subgenus. A small tubercle 
at the base of the moveable finger of the 
chela is distinctive. Rathbun thought the 
gonopod of P, pittieri to be similar to those 
of a group of Mexican and West Indian 
species (Group 1), but in fact it is unique. 


Megathelphusa, new subgenus 


Gonopod with large mesial tooth, visible 
in both cephalic and caudal aspects, and two 
smaller cephalic teeth, varying in position 
and shape. Marginal process not extending 
beyond apex, sperm channel emerging from 
beneath fold of tip of gonopod. Apical 
spines small, facing partly apically, partly 
cephalad. Setae prominent, particularly 
mesial setae. Two tubercles at base of mov- 
able finger of chelae, forming long area 
which is light-colored in fresh specimens. 
Type-species, Pseudothelphusa magna, other 
species, P. richmondi. Megathelphusa (fem.) 
—large river crab. 

Rathbun separated P. richmondi and P. 
magna by the characters of the chelae, stating 
that the tubercle at the base of the fingers 
is lacking in P. richmondz, but in fact the 
two species have very similar chelae. Both 
species of Megathelphusa are widely dis- 
tributed, in contrast to most Costa Rican 
Pseudothelphusidae. 


Pseudothelphusa (Megathelphusa) magna 
Rathbun, 1896 

Holthuis, 1954, p. 33; Bott, 1956, p. 230; 
Smalley, 1964, p. 29. 

Specimens examined: 11.5 mi. NNW Li- 
beria, Guanacaste Prov.; 9 Feb. 1960; 1 4, 
1 2.—Rio Virilla, 2 mi. W San José, San 
José Prov.; 11 Feb. 1960; 1 ¢.—Same Jo- 
cality; 24 Jan. 1961; 2 64,1 2,limm. é. 
—Rio Irigaray, on Pan Am Highway, Guan- 
acaste Prov.; 21 Jan. 1961; 1 2.—Rio Las 
Vueltas, E of Nicaraguan border, Guanacaste 
Prov.; 21 Jan. 1961; 1 6,1 9, 1imm. 6.— 
Small stream, E bank Rio Grande de Tar- 
coles, 3 mi. E Atenas, Alajuela Prov. (580 
m); 11 July 1962; 3 $3,3 22,1 imm— 
Small stream, 0.3 mi. S above locality; 11 
July 1962; 3 63,1 2,3 imm. ¢ ¢6—Rio 


Costa Rican River Crabs 9 


Ciruelas, 0.2 mi. S RR crossing at Ciruelas, 
Alajuela Prov. (800 m); 20 July 1962; 
466. 4 O89. 2 timm: 

Two cephalic teeth not separate, consist- 
ing of two teeth of single medially directed 
process. Gonopods similar to illustrations by 
Holthuis and Bott; some variation shown by 
mesial apical process. 

P. magna is one of the largest species of 
Pseudothelphusidae, although no one has re- 
ported another specimen of the heroic size 
of one of Rathbun’s syntypes (135 x 84); 
the largest Tulane male is 86.5 x 52.3. The 
specimens from Ciruelas were under large 
rocks in a nearly dry gully, and were found 
in pairs, probably copulating. Known from 
Costa Rica to Guatemala. 


Pseudothelphusa (Megathelphusa) richmondi 
Rathbun, 1893 
( Figs. 4-6) 
Nobili, 1897, p. 3 (but the same speci- 
mens listed by Colosi, 1920, p. 20, as P. sp.); 
Boone, 1929, p. 567. 

Specimens examined: Tributary of Rio 
Escondido, 50 mi. from Bluefields, Nica- 
ragua (probably near the town of Rama); 
1 6, the holotype (USNM)—1.1 mi. N 
Turrialba, Cartago Prov. (600 m); 18 July 
1962: 9 66,15 29,3 imm)> ¢.¢. 

Cephalic teeth uneven in size, proximal 
twice size of distal, more pointed. Setae 
prominent, particularly mesial setae. Row of 
short setae on cephalic surface just below 
apical spines. Smaller than P. magna; holo- 
type, 49 x 32.5; largest Tulane male, 62.7 
x 40.6. 

The Costa Rican specimens were found in 
a coffee plantation on a wet hillside. Ditches 
had been dug to drain seepage from the 
field, and the crabs were burrowing into the 
sides of the ditches. P. richmondi is known 
from Nicaragua to Panama. 


Ptychophallus, new subgenus 


Gonopod with expanded tip connected to 
shaft by narrow peduncle. Lateral process of 
apical expansion larger than mesial, bearing 
apical spines; mesial process either narrow 
and fingerlike, or broad and hatchet-shaped. 
Most species with very broad subapical lat- 
eral process, usually bilobed. Apical spines 
directed cephalad. Marginal process folded 
cephalad, not projecting beyond apex. With- 
out marginal setae; lateral setae usually short, 
scattered; marginal and caudal setae present. 


10 Tulane Studies 1n Zoology 


Type-species, Pseudothelphusa  tristant. 
Other species: P. montana, P. tumimanus, 
P. exilipes, and P. xantusit. Ptychophallus 
(masc.)—folded gonopod. P. ¢ristant 1s 
chosen as the type because it is common, 
easily recognized, and fairly typical. Psewdo- 
thelphusa colombiana Rathbun, 1893, from 
Panama and Mexico, should be placed in this 
subgenus on the authority of Rathbun 
(1893). Through an oversight, I did not 
examine the specimens in the U. S. National 
Museum on which Rathbun’s description 
was based. The only other record of this 
subgenus outside of Costa Rica is an errone- 
ous one for P. xantusi from La Guayra, Vene- 
zuela. 


Pseudothelphusa (Ptychophallus) tristant 
Rathbun, 1896 
( Figs. 7-8 ) 

Specimens examined: La Mina, Rio Tor- 
res, San José Prov.; 1 4, the holotype 
(USNM).—1 mi. NW Tabarcia, San José 
Prov.; 20 June 1962; 2 64,5 2%, 3 imm. 
é $—same locality; 17 July 1962; 9 ¢ 4, 
9 22,1 imm. ¢, 3 imm—2 mi. S. Villa 
Colon, San José Prov.; 29 June 1962; 2 4 2, 
72 2.—same locality; 4 July 1962; 1 ¢, 
3 22, 6 imm. 36 4¢—3 mi. E. Atenas, 
Alajuela Prov. (580 m); 7 July 1962, 4 ¢ 4, 
> 22°) 1 imm—O0O5 mi. S Cebadilla,-Ale- 
juela Prov; 1. July 1962; 6.6 6,9 2? 1 
ovigerous), 6 imm. 6 6, 2 imm—2.7 mi. 
S El Roble, Heredia Prov. (1200 m): 13 
July 1962; 2 66,1 2—2.5 mi. NE Santi- 
ago Puriscal, San José Prov., 17 July 1962, 
26 646,16 22,4imm. 6 ¢.—0.8 mi. W 
Piedades, San José Prov.; 26 July 1962; 12 
66,26 664, (4 with small crabs on abdo- 
men), 6 imm. ¢ ¢. 

Only Ptychophallus with mesial apical 
lobe broad and hatchet-shaped. Proximal 
process of subapical lobe small, setae sparse. 
Fingers of larger chelae gaping in largest 
males, closed tightly in smaller males. 


Abundant in the hills and mountains 
south of San José. P, tristani is more ter- 
restrial than P. tumimanus or P. montana. 
Typically, P. tristant is found under rocks or 
logs at the edge of streams, or even some 
distance from the stream edge. A cavity 
under the rock or log, filled with water, 
forms part of the crab’s burrow. 


Vol. 12 


Pseudothelphusa (Ptychophallus) montana 
Rathbun, 1898 
( Figs. 9-10) 
P. convexa, Rathbun, 1898. 

Specimens examined: Alto La Palma, 
San José Prov.; 2 6 6), 2) So theseypes 
(USNM ).—Palmar, Puntarenas Prov., 1 ¢, 
holotype of P. convexa (USNM).—0.6 mi. 
S. Alto La Palma, San José Prov.; 9 July 
1962: 2 26, 2 99, 0:2 “mr SeAlore 
Palma; 9 July 1962; 2 ¢ 6, 3 212) 2aane 
6 6 —Rio Honduras, 3.0 mi. N continental 
divide, San José Prov.; 9 July 1962; 9 ¢ ¢.— 
11 mi. NE Turrialba, Cartago Prov. (770 
m); 6 July 1962; 4 ¢/6,5 2°, 6 timmy: d'd 
same locality; 21 July 1962; 13 64, 14 
22,17 imm. ¢ 6.4 mi. E La Suiza, Car- 
tago: Prov.; 18 July 1962. i "cee 
imm. é. 


Similar to P. tumimanus and P. exilipes. 
Medial process of gonopod long, slender. 
Subapical lateral process bilobed, proximal 
lobe acutely angled, caudal surface with dis- 
tinct depression between lobes. Small spe- 
eres (309 = 13ale): 


Rathbun (1898) gave a confusing account 
of P. montana and P. convexa. The only dis- 
tinct difference between the types is that 
the two subapical lateral lobes of P. montana 
are not so distinct, the more proximal lobe 
not so acute, and the depression between 
the two lobes on the caudal surface more 
shallow. However, her figures (1898, p. 516 
and p. 526) show the opposite, that is P. 
montana with a deep depression on the 
caudal surface. Since the gonopods of the 
material examined by me vary in the shape 
of the subapical lateral lobes and degree of 
concavity of the caudal surface, P. convexa 
should be considered a synonym of P. mon- 
tana. The name P. montana is chosen in 
preference to P. convexa because the speci- 
mens studied and illustrated in this work 
are from the type locality of P. montana and 
from the surrounding region. 

The lack of females from Rio Honduras 
is due to the mixture of P. tamimanus and 
P. montana in the collection, and the diffi- 
culty of distinguishing the females. All the 
females were arbitrarily assigned to the more 
common P. twmimanus. 

Found in streams, and under boards at 
an abandoned sawmill (northeast of Tur- 
rialba ). 


No. 1 


Pseudothelphusa (Ptychophallus) tumimanus 
Rathbun, 1898 
( Figs. 11-12) 

Specimens examined: Cachi, Cartago Prov., 
1 ¢, the holotype (USNM)—2 mi. S$ 
Cariblanco, Heredia Prov. (1200 m); 25 
june 1962; 3 64,7 22, 1 imm—same lo- 
cality, 28 June 1962,4 66,5 22 (2 with 
juveniles on abdomen), 2 imm. ¢ ¢.—same 
locality; 14 July 1962; 10 ¢ 6,5 ? 2.—Rio 
Honduras, 3.0 mi. N continental divide, San 
José Prov.; 9 July 1962; 166 6, 31 22, 16 
imm. 6 ¢, 5 imm—1.2 mi. SE El Roble, 
Heredia Prov. (1300 m); 13 July 1962; 
Peo. qmm. ¢ . 

Lateral subapical process relatively larger 
than in other species of subgenus, tapering 
more gradually proximally, with scalloped 
border, and with short, heavy setae scattered 
along proximal part of lateral process. 

A large species for the subgenus (Tulane, 
60.3 x 35.7; holotype, after Rathbun, 70.2 x 
42.2). Most specimens, and all the larger 
ones, were found in streams under rocks, or 
moving freely on the bottom. 

Both Temnocephala and Branchiobdellidae 
were found on P. tumimanus, but they were 
mutually exclusive; the Temnocephala oc- 
curred on the population near Cariblanco, 
and the Branchiobdellidae on the crabs from 
Rio Honduras. The two populations are 
separated by about 18 miles of very rugged 
mountains. Hobbs and Villalobos (1958) 
report both groups of commensals occurring 
together on Pseudothelphusa lamellifrons 
Rathbun, 1893. 


Pseudothelphusa (Ptychophallus) extlipes 
Rathbun, 1898 
( Figs. 13-14) 

Specimens examined: Santa Maria de Dota, 
San José Prov.; 2 66,4 22 (USNM). 

Mesial apical lobe of gonopod down- 
turned, more proximal than in P. montana; 
rounded distal lobe formed from margin at 
apex. Marginal and caudal setae prominent, 
individual setae long; long, scattered setae 
on lateral surface proximal to widest part 
of subapical lobe. Apical spines restricted to 
distal part of “patch”. 

The holotype of P. exilpes is a female 
from El Coronel. The present description 
and illustrations are based on a male from 
Santa Maria de Dota, about 51 kilometers 
from El Coronel, and identified with the 


Costa Rican River Crabs 11 


type by Rathbun. Males from the type- 
locality would be very valuable. Collecting 
six miles from El Coronel yielded specimens 
only of P. tumimanus and P. montana. Simi- 
lar problems of confirming the identity of 
female types are common in the Pseudo- 
thelphusidae. 


Pseudothelphusa (Ptychophallus) xantust 
Rathbun, 1893 
CEive5)) 
Nobili, 1897, p. 3; Colosi, 1920, p. 19 (in 
the synonymy of P. fossor). 

Specimens examined: Boruca, Puntarenas 
Prov.; 3 66,1 imm. (USNM). 

Without mesial apical lobe, the lobe 
placed subapically instead. Lateral subapical 
lobes poorly developed. 

Although P. xantusi is a rather aberrant 
member of the subgenus, the folded tip bears 
the apical spines exactly as in other species 
of Ptychophallus, and the lateral subapical 
lobes are typical in their shape and position, 
although not nearly as broad as in the other 
species. 

The holotype of P. xantusi is a female, 
locality unknown, but probably from Mexico, 
and almost certainly not from Costa Rica. 
In my opinion this species will eventually 
have to be declared a species dubia and a 
new name assigned to the distinctive species 
from Boruca. However, judgment should 
be deferred until the river crabs of Mexico 
are much better known. 


ACKNOWLEDGEMENTS 


For help in the field, I am indebted to 
Dr. John DeAbate, Sr. Don Salvador 
Jiménez-Canossa, Dr. R. D. Suttkus, and 
especially my wife. Drs. Herbert W. Levi, 
F. A. Chace, Jr., and Raymond B. Manning 
were most helpful in loaning specimens; 
Dr. Manning was the subject of the greater 
part of these requests, with which he was 
most patient. This research was supported 
by a grant from the Systematics Section of 
the National Science Foundation (NSF- 
G20862), whose aid is gratefully acknowl- 
edged. 


V. REFERENCES CITED 


Aucock, A. 1910. On the classification of 
the Potamonidae (Thelphusidae). fee. 
Indian Mus. 5: 253-261. 

BoongE, L. 1929. A collection of brachyuran 
Crustacea from the Bay of Panama and 


Tulane Studies rn Zoology 


IG “13 I4 


Explanation of the Figures 
Right gonopods (usually distal portion only) and chelae of Costa Rican Pseudothelphusi- 
dae. 1-3, Pseudothelphusa pittieri; 4-6, P. richmondi; 7-8, P. tristani; 9-10, P. mon- 
tana; 11-12, P. tumimanus; 13-14, P. exilipes; 15, P. xantusi; 16-17, Epilobocera cuben- 
sis. Drawn to different scales. 


No. 1 


the fresh waters of the Canal Zone. Bull. 
Amer. Mus. Nat. Hist. 58: 561-583. 
Bort, R. 1955. Die Stisswasserkrabben von 
Afrika (Crust. Decap.) und ihre Stam- 
mesgeschichte. Ann. Mus. Roy. Congo 
Belge, C--Zool., Ser. III, III, Vol. 1(3): 
209-352, pl. 1-30. 
_ 1956. Dekapoden (Crus- 
3. Susswasser- 
Senck. Biol. 


~ tacea) ¢ aus El Salvador. 
krabben (Pseudotelphusa). 
37: 229-242. 


CoLosi, G. 1920. I Potamonidi del R. Museo 
Zoologica di Torina. Boll. Mus. Zool. 
Anat. Comp. R. Univ. Torino 35(734): 
1-39. 


MILNE-Epwarps, H. 1853. Observations sur 
les affinités zoologiques et la classifica- 
tion naturelle des Crustacés. Ann. Sei. 
Nat., Zool. 18(3): 109-162. 

Hopes, Horton H., and ALEJANDRO VILLA- 
LOBOS F.. 1958. The exoskeleton of a fresh- 
water crab as a microhabitat for several 
invertebrates. Virginia J. Sci. (N.S.) 9: 
395-396. 

HouruHuis, L. B. 1954. On a collection of 
decapod crustacea from the Republic of 
El Salvador (Central America). Zool. 
Verhandel., Leiden, No. 23: 1-43. 

LATREILLE, P. A. 1825. Fiamilles naturelles 
du Regne animal. Paris. 


Nosiui, G. 1896. Di un nuovo genere di 
Crostacei decapodi raccolto nel Darien 
dal dott. E. Festa. Boll. Bus. eee Anat. 
Comp. R. Univ. Torino 11(238) : 1-2 


1897. Viaggio AG Dr. 
~ Enrico Festa nella pepe ee dell’ Ecua- 
dor e regioni vicine. I decapodi terrestri 
e d’acqua dolce. Boll. Mus. Zool. Anat. 
Comp. R. Univ. Torino 12(275) : 1-6. 


ORTMANN, A. E. 1893. Die Decapoden- 
Krebse des Strassburger Museums, mit 
besonderer Berucksichtigung der nov 


Herrn Dr. Déderlein bei Japan und den 


Costa Rican River Crabs 13 


Liu-Kiu-Inseln gesammelten und zur Zeit 
im Strassburger Museum aufbewahrten 
Formen. VII. Theil. Zool. Jahrb., Syst. 
7; 411-495. 

RATHBUN, M. 1893. Descriptions of new 
species of American fresh-water crabs. 
Proc. U. S. Nat. Mus., 16: 649-661. 


1896. Descriptions of 
two new species of fresh-water crabs from 
Costa Rica. Proc. U. S. Nat. Mus. 18: 


Bee) 

. . 1898. A contribution to 
the knowledge of the fresh-water crabs of 
America—The Pseudothelphusinae. Proc. 
U. S. Nat. Mus. 21: 507-537. 

_. 1905. Les crabes d’eau 

douce (Potamonidae). Nowv. Arch. Mus. 

Hist. Nat. Paris, ser. 4, 72 159-321. 


RiogA, E. 1952. Estudios carcinologicos. 
XXVIII. Descripcion de un nuevo género 
de potamonidos cavernicolos y ciegos de 
la Cueva del Tio Ticho, Comitan, Chis. 
An. Inst. Biol., Mexico 23(1-2): 217-225. 

SAUSSURE, H. DE. 1857. Diagnoses de quel- 
ques Crustacés nouveaux des Antilles et 
du Mexique. Rev. Mag. Zool. 9(2) :304- 
306. 


SELANDER, R. and P. VAURIE. 1962. A gazet- 
teer to accompany the “Insecta” volumes 
of the “Biologia Centrali-Americana”’. 
Amer. Mus. Novitates, No. 20999: 1-70. 


SMALLEY, A. 1964. A terminology for the 
gonopods of the American river crabs. 
Syst. Zool. 13:28-31. 

STIMPSON, W. 1860. Notes on North Ameri- 
can Crustacea, No. 11. Ann. Lyc. Nat 
(East: Newent eliO=246e 

YOUNG, C. 1900. The stalk-eyed Crustacea 
of British Guiana, West Indies and Ber- 
muda. Watkins, London. 

ZIMMER, C. 1914. Beitrag zur Kentniss der 
Stisswasserdekapoden Kolumbiens. Mem. 


Neuchdteloise des Sciences Naturelles 5: 
1-8. 


August 21, 1964 


MYSIDOPSIS ALMYRA, A NEW ESTUARINE MYSID CRUSTACEAN 
FROM LOUISIANA AND FLORIDA 
THOMAS E. BOWMAN, 
Division of Marine Invertebrates, 
Smithsonian Institution, 


W ashington, 


ABSTRACT 
Mysidopsis almyra is described from 
Lake Pontchartrain, Louisiana, St. An- 
drews Bay, Florida, and Buttonwood 
Canal, Florida. 


Two species of Mysidopsis are known 
from the Atlantic and Gulf of Mexico coasts 
of the United States. M. bigelows W. Tat- 
tersall (1926) occurs from New England to 
Louisiana, while M. furca Bowman (1957) 
is known only from the type-locality, off 
South Carolina. A third species, collected 
from brackish waters in Florida and Louisi- 
ana, is described below. 


Mysidopsis almyra,' new species 
Figures 1-24 

Mysidopsis sp., Darnell, 1961, pp. 555-556. 

Description. Length, from anterior margin 
of rostrum to end of telson, varies seasonally: 
8.1-9.4 mm in 6 adults collected 19 Feb. 
1954, 4.2-5.3 mm in 5 adults collected 30 
July 1953 in Lake Pontchartrain, Louisiana. 
Anterior margin of carapace broadly round- 
triangular, not produced between eyes as 
rostrum; anterolateral angles rounded; pos- 
terior margin evenly concave, thoracic somite 
8 and a small portion of thoracic somite 7 
exposed in dorsal view. Eye large, cornea 
kidney-shaped, without ocular papilla. Tel- 
son slightly shorter than pleonite 6, lingui- 
form, with broadly rounded apex; lateral 
margins each with about 20 spines along 
entire length; apex with 6-7 pairs of closely 
set long strong spines, central pair longest, 


1 From the Greek aduvoedc, brackish. 


D.C. 20560 


about 1/4 as long as telson. First segment 
of peduncle of antenna 1 longer than third, 
with rounded lobe bearing long recurved 
setae arising from inner distal angle; male 
lobe slender, about as long as first segment, 
inner margin thickly set with setae. Scale 
of antenna 2 narrowly lanceolate, 2-seg- 
mented, distal segment about 0.4 as long 
as proximal; distal segment of peduncle pro- 
duced into spine on outer distal corner. 
Labrum rounded anteriorly; posterior margin 
with small central margination; middle 2/3 
armed with short setae. Molar of mandible 
obsolete; incisor curved so that in some 
views it appears bipartite, with 9 teeth in 
left mandible, 5 teeth in right; left lacinia 
mobilis broad, with 6 teeth; right lacinia 
much smaller, constricted at base, with 5 
teeth; spine row of 7-8 spines, with numer- 
ous setae interspersed among spines; palp 
well developed. Outer plate of maxilla 1 
with 9 spines at apex; inner plate with 2 
setae at apex and | on outer margin. Proxi- 
mal lobe (lobe of second segment) of 
maxilla 2 with 4 setae on truncate apex; 
exopod with 4 setae. Thoracic leg 1 (maxil- 
liped) short and stout. Leg 2 (endopod of 
2nd thoracic appendage) slender; segment 6 
slightly longer than segment 5; segment 7 
ending in nail, posterior margin with 4 
robust long barbed setae, anterior margin 
with about 10 long naked setae. Legs 3-7 
slender, subequal; tarsus of 2 segments, first 
about 4 times as long as second; prehensile 
distal end formed by long slender dactyl and 
5 long setae, 4 inserted at distal end of first 
and 1 at distal end of second tarsal segment. 


EDITORIAL COMMITTEE FOR THIS PAPER: 


Dr. WILLIAM D. CLARKE, Marine Sciences Section, General Motors Defense Re- 
search Laboratories, Goleta, California 


SIDNEY S. HERMAN, Assistant Professor of Biology, Lehigh University, Bethlehem, 


Pennsylvania 


Dr. OLIVE S. TATTERSALL, Pendeen, 66, Sinah Lane, Hayling Island, Hants, England 


15 


16 Tulane Studies in Zoology Vol. 12 


Figures 1-14. Mysidopsis almyra, new species: 1. anterior part of female, lateral; 2. 
male, dorsal; 3. telson, dorsal; 4. male antenna 1, proximal segments, dorsal; 5. scale of 
female antenna 2, dorsal; 6. labrum; 7. right mandible, external (ventral) view; 8. right 
mandible, gnathobasic process, external view; 9. same, internal (dorsal) view; 10. left 
mandible, gnathobasic process, internal view; 11. same, oblique internal view; 12. 
maxilla 1; 18. maxilla 1, outer plate; 14. maxilla 2. 


No. 1 


Leg 8 much shorter than other legs. Male 
pleopod 1 with lobe bearing 6 setae at base 
of endopod. Endopod of male pleopod 4 
with 2 lobes bearing 1 and 6 setae respec- 
tively; exopod longer than endopod, with 
long barbed robust apical spine. Exopod of 
uropod about twice as long as telson (ex- 
cluding terminal spines), curved gently out- 
ward; endopod about 3/4 as long as exopod, 
armed on ventral surface near medial margin 
distal to statocyst with a single long spine. 

Color. In preserved specimens black chro- 
matophores are distributed as follows: Dor- 
sally, 1 pair at base of telson; ventrally 2 
pairs on thorax, 1 in midline near posterior 
margin of pleonites 1-5, 1 on each posterior 
oostegite near base. 

Types. Male holotype, USNM_ 110924, 
female allotype, USNM 110925, and 8 para- 
types, from station A. IL 188, 2.4 km off- 
shore from the mouth of Bayou St. John, 
Lake Pontchartrain, Louisiana, collected 28 
Dec. 1953, by Rezneat M. Darnell. More 
than 450 specimens collected by Dr. Dar- 
nell from other stations in Lake Ponschar- 
train in 1953-54 have also been designated 
as paratypes. 

Occurrence. In addition to the specimens 
from Lake Pontchartrain, I have identified 
specimens of M. almyra from St. Andrews 
Bay, Florida, collected by Thomas L. Hop- 
kins, and from the north end of Buttonwood 
Canal, connecting Florida Bay at Flamingo 
with Coot Bay, in the Cape Sable region of 
southern Florida, collected by Raymond B. 
Manning (cf. Tabb and Manning, 1961; 
Tabb, Dubrow, and Manning, 1962). At all 
3 localities the salinity is low, at least sea- 
sonally. At the Lake Pontchartrain stations 
from which I have specimens of M. almyra, 
the salinity varied from 2.0-5.2°/o0, and 
Darnell (1958) reports a salinity during 
his study (July 1953 to August 1954), of 
1.2-18.6°/o0, with an average of less than 
6°/oo and a maximum of less than 9°/o9 for 
most months. In the St. Andrews Bay sys- 
tem the salinity ranges from low values in 
the upper reaches to values only slightly 
below full ocean salinity in St. Andrews Bay 
proper, West Pass, and East Pass (Jones 
and Ichiye, 1960; Ichiye and Jones, 1961). 
Specimens of Mysidopsis almyra were col- 
lected by Hopkins at stations $3 and S5 
(Hopkins, 1963) in St. Andrew Bay and 
West Pass respectively, and the salinities at 
the times of collection were 33.1°/o9 and 


New Mysid Crustacean Ly 


Figures 15-19. Mysidopsis almyra, new spe- 
cies: 15. leg 1; 16. leg 2; 17. leg 2, dis- 
tal segment; 18. leg 3, distal segments, 
viewed from above; 19. leg 8. 


: 


EZ 


LBA 
oy 4 
| 


DAA 


e¢ 


GeoeoC eC? QOEOLO CE LU TL 


oe 


» 


\ || 
los 


Figures 20-24. Mysidopsis almyra, new spe- 
cies: 20. pleopod 1, male; 21. pleopod 1, 
male, endopodal lobe; 22. pleopod 4, male; 
23. left uropod, ventral; 24. genital appen- 
dage, male. 


= 


24 


18 Tulane Studies 1n Zoology 


27.3-33.7°/oo respectively (Hopkins, in litt.). 
At the site of collection in Buttonwood 
Canal the salinity undergoes marked fluctu- 
ations, varying from less than 18°/99 to more 
than 40°/o9 (Tabb, Dubrow, and Manning, 
1959). 

Mysidopsis almyra is very abundant in 
Lake Pontchartrain. Quoting Darnell (1961), 
the zooplankton “is dominated by the cala- 
noid copepod (Acartia tonsa) and to a lesser 
extent by adult schizopods (Myszdopszs sp.) 
and larval penaeid shrimp.” M. almyra is 
an important item in the diet of a number 
of Lake Pontchartrain fishes (Darnell, 1958). 
Both young and adult Anchoa mitchilli dta- 
phana feed on this mysid; in other fishes 
(Ictalurus furcatus, Cynoscion arenarius, C. 
nebulosus, Micropogon undulatus, Sciaenops 
ocellatus) only the young specimens feed 
on Mysidopsis, the older individuals turning 
to larger prey. Finally, the young of some 
fishes (Menidia beryllina and Baitrdiella 
chrysura) prey mostly on copepods; as these 
fishes grow older, they come to depend more 
on mysids. 

Remarks. Only 3 species of Mysidopsts, 
M. angusta G. O. Sars, M. didelphys Nor- 
man, and M. indica W. Tattersall, have a 
single spine on the uropodal endopod near 
the statocyst. These species differ from M. 
almyra in having very short distal segments 
of the antennal scales and 3-segmented tarsi 
on thoracic legs 3-8, and their telsons are 
quite different. Only 1 species of Mystdop- 
sis, M, bigelowi W. Tattersall, has been re- 
ported from the Gulf of Mexico: Tattersall 
(1951) reports it from Calcasieu Pass, Lou- 
isiana (I have examined these specimens 
and confirm his identification); Clarke 
(1956) records it from 10 miles off Bara- 
taria Light, Louisiana, and the U. S. Na- 
tional Museum has a single specimen col- 
lected by the M/V Silver Bay off southern 
Florida (26°20'N, 83°02’W). M. bigelowi 
is easily distinguished from M. almyra by its 
smaller eye, unsegmented antennal scale, the 
very robust thoracic leg 2, the presence of 


Vole, 


5 spines near the statocyst, and the armature 
of the telson. 


REFERENCES CITED 


BOWMAN, THOMAS E. 1957. A new species 
of Mysidopsis (Crustacea: Mysidacea) 
from the southeastern coast of the United 
States. Proc. U. S. Nat. Mus. 107(3378) : 
1-7. 

CLARKE, WILLIAM D. 1956. A further de- 
scription of Promysis atlantica Tatter- 
sall (Crustacea, Mysidacea). American 
Mus. Novitates 1755: 1-5. 

DARNELL, REZNEAT M. 1958. Food habits of 

fishes and larger invertebrates of Lake 
Pontchartrain, Louisiana, an estuarine 
community. Publ. Inst. Mar. Sci. Univ. 
Texas 5: 353-416. 
AS an IER 1961. Trophic spectrum 
of an estuarine community, based on 
studies of Lake Pontchartrain, Louisiana. 
Ecology 42(3): 553-568. 

HOPKINS, THOMAS L. 1963. The variation in 
the catch of plankton nets in a system of 
estuaries. J. Mar. Res. 21(1): 39-47. 

ICHIYE, TAKASHI and MEREDITH L. JONES 
1961. On the hydrography of the St. 
Andrew Bay System, Florida. Limnol. 
Oceanogr. 6(3) : 302-311. 

JONES, MEREDITH and TAKASHI ICHIYE 1960. 
Hydrographic data of the St. Andrews 
Bay system, Florida. Florida State Univ. 
Oceanogr. Inst. Contr. 148: 1-56 (mimeo- 
graphed). 

TABB, DURBIN C., DAvip C. DUBROW, and 
RAYMOND B. MANNING 1959. Hydro- 
graphic data from the inshore bays and 
estuaries of Everglades National Park, 

_ Florida, 1957-1959. Mar. Lab. Univ. Mi- 
ami Rept. 59-5: 1-26 (Mimeographed). 

PA teen eries eRe oem The ecology of 
northern Florida Bay and adjacent estu- 
aries. Florida State Board Conserv. Tech. 
Ser. 39: 1-79. 

TABB, DURBIN C. and RAYMOND B. MANNING 
1961. A checklist of the flora and fauna 
of northern Florida Bay and adjacent 
brackish waters of the Florida mainland 
collected during the period July, 1957 
through September, 1960. Bull. Mar. Sci. 
Gulf and Caribbean 11(4): 552-649. 

TATTERSALL, WALTER M. 1926. Crustaceans 
of the orders Euphausiacea and Mysida- 
cea from the western Atlantic. Proc. 
U. S. Nat. Mus. 69(2634): 1-28, pls. 1-2. 

So ee 1951, VAtSreviewsotethe 
Mysidacea of the United States National 
Museum. Bull. U. S. Nat. Mus. 201: 1- 
292. 


August 21, 1964 


TULANE STUDIES IN ZOOLOGY 


Volume 12, Number 2 


February 23, 1965 


AGE DETERMINATION OF THE COTTON RAT (SIGMODON HISPIDUS)* 


ROBERT K. CHIPMAN, 
Department of Zoology, 
University of Vermont, 

Burlington, Vermont 


CONTENTS 

BERNE SHRUG Ss ae. ee eee 19 
II. INTRODUCTION. 20 
NBIVIACRER TAT. -AINID IME SE @D Si ee eee 21 
PWemmlbaBOLACOLV SUUGY =. 228s 8 tA a ate eee ee NE ee, ED 

B. Field study 22 
Pere MLA OOCy MCAS UT I CICS ea es ee 22 
vemise aera dM OltS ae a See 2 eS SO ee ee serenely rm eke IZA 

COMBE LO UGE OI Pea ea GON he = a octet is IE a ng Bre om ta sey SD 

ILD) Fang ER es Gil eterna a nee ee eels Rk Paes nas Oe BS rj oe sees. eae egy Wi, 

AS CIC CC iaiere naket 248 ne) oan hae i 28 

MMM INS VC ele en oh ee ee ea Be, ein Ns ee ee eee ee eae SN 

MGB FL) CLES EU lee Marsters BS ne ON a AM I in ded on eee BY 
emPESUSSION ANDi CONGHU SIONS 25: 22 eee ot Se ee OD 
WAP NGRINO WALLED GENIE IN GUS etn soe ie ee A ee ee 37 
WIRRIMPIRERIPNGES @IVGED 2-2 ee OF 


I. ABSTRACT 

A study based on 316 known-age 
specimens of the cotton rat, Sigmodon 
hispidus hispidus, from southeastern 
Louisiana consisted of a laboratory and 
a field study. The categories of mor- 
phological characters examined were: 
body measurements; pelage and molt- 
ing; reproductive activity; teeth; skel- 


changes of these characters were stud- 
ied through twelve months of age. The 
laboratory study showed that body 
length, molting stage, epiphyseal fu- 
sion, skull measurements, and dry lens 
weight combine to give a high de- 
gree of success for age-determination 
through six months of age. 

The field study consisted of releas- 


ing 96 known-age cotton rats and suc- 
cessive periods of retrapping. The re- 
trapping data support the conclusions 
of the laboratory study. Weight as an 
age-determining character is discussed 
and evaluated from the field data of 
this and other studies. 


etal growth; and lens weight. The 


* This paper is based on a dissertation 
submitted in partial fulfillment of the re- 
quirements for the Ph.D. degree in Zoology 
at Tulane University, New Orleans, Lou- 
isiana, 1963. 


EDITORIAL COMMITTEE FOR THIS PAPER: 


KYLE R. BARBEHENN, Lecturer on Biology, Department of Biology, University of 
Pennsylvania, Philadelphia, Pennsylvania 


JAMES N. LAYNE, Associate Professor of Zoology, Department of Conservation, Cor- 
nell University, Ithaca, New York 


NorMAN C. NEGUS, Associate Professor of Zoology, Department of Zoology, Tulane 
University, New Orleans, Louisiana 


19 


20 Tulane Studies n Zoology 


Il. INTRODUCTION 


The need for reliable criteria for esti- 
mating the age of wild animals has been 
noted by many researchers and has been re- 
viewed by Alexander (1958). Support for 
the study of age-indicating techniques .has 
been devoted primarily to the larger game 
mammals due to sporting interests. Even 
when studies have been undertaken on 
smaller mammals, the emphasis is still placed 
on those species that are of interest either 
for hunting or for their commercial fur 
value. With the recent interest in the study 
of populations of small rodents and particu- 
larly the occasional dramatic fluctuations in 
their numbers, there is an increasing need 
for accurate methods for determining age 
classes. 


The degree of accuracy necessary for esti- 
mating the age of any given animal will de- 
pend on the species itself. For example, if 
the species does not breed until it is several 
years old, the estimation of age in units of 
time of less than one year will have little 
practical value. If, however, the species 
breeds at the end of its first year, then esti- 
mation of age to one year or even less would 
be desirable to distinguish between young 
of the year and adults for the next breeding 
season. In the case of small rodents more 
precise estimation of age is necessary as 
many of the young will become reproduc- 
tively active during the breeding season in 
which they were born. Three or more gen- 
erations in a breeding season of a small 
rodent are not uncommon and may be the 
rule especially if the species breeds through- 
out the year. Occasional trapping in the 
animal’s natural habitat will not solve the 
problem of age determination as the age of 
the captured animals so collected will be un- 
known, and only rough approximations of 
age classes can be formulated. A solution 
can only be found by first studying the de- 
velopment of various morphological char- 
acters on animals whose individual ages are 
known. Ideally, field studies should be 
undertaken concurrently on known-age ani- 
mals to verify or adjust the laboratory de- 
rived data. 

Thus, the purpose of this study was to 
determine useful age-determination  char- 
acteristics from laboratory-raised cotton rats 
(Sigmodon hispidus) and to field-test the 
application of those techniques. Hopefully, 


Vol. 12 


the techniques that are successful for deter- 
mining the age of the cotton rat will aid 
other researchers in age determination of 
small rodents. 

Studies on growth of the cotton rat are 
limited largely to weight and measurement 
data. Svihla (1929) described cotton rats at 
birth, their early growth, and their ability to 
feed at about ten days of age. Meyer and 
Marsh (1943) noted that cotton rats be- 
come sexually mature at six to seven weeks. 
In the most elaborate study of growth of the 
cotton rat Meyer and Meyer (1944) pre- 
sented considerable data on the growth of 
the young and additional data on growth 
through 15 months. Body weights are given 
in units of 5O days of age, but do not give 
good indication of being reliable criteria for 
aging of the animal. Furthermore, the sam- 
ple size is limited to three to six animals. 
Information was presented that the rate of 
growth is influenced by the age of weaning. 
Data were also given for growth of various 
endocrine glands, but the areas of overlap 
from one age group to another were too ex- 
tensive for estimating the age. No data were 
presented on body measurements, the growth 
of bones, the progression of molts, the de- 
velopment of the baculum, or the several 
other categories investigated in this study. 

McIntire, Schweigert, and Elvehjem (1944) 
studied the increase in weight of the cotton 
rat to six weeks of age. The authors noted 
that both sexes grow at the same rate al- 
though the female is somewhat smaller than 
the male at any given age. Odum (1955) 
indicated breeding begins at a weight of 62- 
87 grams and at an age of 40-50 days. Indi- 
vidual size of the animals varied with the 
density of the population, animals being 
larger at lower than at higher densities. Data 
on weight were given for a limited number 
of known-age individuals. Odum also noted 
that very few individuals survived six months 
of live trapping, which may give some indi- 
cation of longevity under field conditions. 

Sealander and Walker (1955) suggested 
that size is no indication of reproductive 
capabilities. The population studied by these 
authors was aged by the use of the laboratory 
weight data of Meyer and Meyer (1944). 
Age classes based on body measurements 
were thought to be of little value as these 
classes had little relationship to weight. Keys 
(1958) followed the rate of embryonic and 
early postnatal development. He noted that 


No. 2 


the cotton rat is quite precocious at birth 
and develops at a remarkably rapid rate. His 
study was not carried beyond 15 days of age. 


Ill. MATERIAL AND METHODS 
A. Laboratory Study 


A breeding colony of wild cotton rats 
from southern Louisiana was organized in 
the spring and summer of 1960. Some of 
the young born of the wild cotton rats were 
also used as breeders in the laboratory. 
Breeding pairs were housed in large cages. 
Large fruit juice cans and cotton batting 
were found to make satisfactory nesting sites. 
Little fighting occurred after the first few 
days of pairing. 

The females usually bore young two to 
four months after pairing. The male ignored 
the newborn young, and was left continually 
in the cage to take advantage of the post- 
partum estrus. The breeding females were 
palpated every two weeks to determine preg- 
nancies. Once a litter was expected the cage 
was checked daily. At parturition the female 
would bar the male from the nest can; he 
then made a nest elsewhere in the cage. This 
action normally served to establish the date 
of birth. Also, as the eyes of the young are 
closed at birth but open the next day, a 
quick check of the newborn young would 
verify the date of birth. 


The laboratory-born young that were used 
as breeders were usually paired when weaned 
(three weeks). At this age males and females 
were amicable. If pairing was delayed until 
after six weeks, some fighting resulted. In 
a few instances when the newborn young 
were a week to ten days old, the female, 
whether wild or laboratory raised, would 
viciously attack the male, chewing the hide 
from the back of the head to the sacral 
region. The pair was then separated and no 
further attempt was made to breed the 
female, although invariably a litter was born 
about two weeks after the separation. 

The cotton rats were fed a diet of Wayne 
Lablox exclusively. Water was available ad 
libitum. The breeders were occasionally fed 
fresh greens in the earlier stages of this 
study. Most of the laboratory-bred cotton 
rats were secretive during the day, or at 
night when any activity was taking place in 
the laboratory. Although I made constant 
efforts to handle and tame the cotton rats, 
especially the young, the attempt proved use- 


Age Determination of Cotton Rat Ail 


less. The tamest animals in the colony were 
wild-born, adult breeders. Generally the ani- 
mals were removed from their cages by 
trapping them in their nest can or by chas- 
ing them into a Sherman live trap. The 
animals were then etherized for examination. 
Once subdued the animals would not bite 
but would still try to escape. 

Meyer and Meyer (1944) showed that 
cotton rats weaned at 10 days of age did not 
gain weight as rapidly as those weaned at 
20 or 30 days, the difference between the 
latter two ages being slight. Rabasa (1952) 
showed growth rates in albino rats to vary 
depending on the number of individuals per 
cage. For these reasons all cotton rats were 
weaned at the same age (21 days) and, 
with the exception of the few used for 
breeding purposes, were caged individually. 
Cages contained between 110 and 120 square 
inches of floor space and were supplied with 
coarse sawdust or shavings, a nest can of 
suitable size, and some cotton for nesting 
material. The nesting material was exten- 
sively used during winter, but was generally 
ignored during summer, although the tem- 
perature in the air-conditioned animal room 
was seldom lower than 65° F or higher than 
75° F. I attempted to limit the photoperiod 
to that available as sunlight. Occasionally 
the animals received additional light when 
night work was necessary. The variations of 
light and temperature were kept to a mini- 
mum whenever possible, but may have af- 
fected some of the laboratory data, as will 
be discussed below. 

The study was based on 12 samples. The 
first sample was made up of one-month-old 
animals. Successive samples were one month 
older than previous samples through 12 
months of age. Each sample was derived 
from 3 to 5 separate litters and was planned 
to be composed of 5 males and 5 females. 
Cotton rats were assigned at the time of 
weaning to the older incomplete month-age 
samples. The first few litters were composed 
predominantly of males, causing the 12- 
month sample to have an undesirably high 
number of this sex. With the exception of 
the conditions described above, the animals 
were assigned to a sample at random. A few 
individuals died or were accidently killed 
prior to attaining their desired age, causing 
some deviation from this plan. Adjustments 
were made where possible. 

Three wild-caught individuals were kept 


22 Tulane Studies tn Zoology Vol. 12 
TABLE 1. 
Distribution of individuals forming the laboratory study. 
Age of Sample (Months) 

1 Zi 3 5 6 i 8 9 10 1 2, 18 

Males 5 5 6 5 5 5 5 6 3 3 4 9 2 

Females 6 5 6 5 4 5 8 1 W 6 5 A 1 

Total 11 10 Ak 10 9 10 13 7 10 9 9 ial 3 
Number of litters 

represented 4 5 5 5 a 4 5 3 3 3 4 4 ~ 


in captivity as breeders for 16 months. These 
were judged to be two or more months old 
at capture and are thus considered to have 
been 18 months or older when sacrificed. 
The data from these individuals were incor- 
porated where possible. The composition of 
each month-age sample as to number, sexes, 
etc., is given in Table 1. The animals used 
in this study came from litters ranging from 
5 to 10 young. No significant difference 
existed in weight or body measurements be- 
tween the different sized litters. 


All cotton rats were etherized and exam- 
ined every two to four weeks for molting 
and reproductive condition. Individuals 
were sacrificed with ether when they had 
reached the desired age in months and on 
the same day of the month as their date of 
birth. The animal was then weighed, and 
the standard body measurements {total, tail, 
hind foot (not including nail), and ear 
(measured from the notch) lengths} were 
taken. The cotton rat was then skinned, the 
pelt being pinned out flat for drying. Both 
eyes were removed, placed in formalin, and 
the lenses later removed. The lenses were 
dried and weighed on a Mettler analytical 
balance to 0.1 mg. 

The skull was severed, dried, and cleaned 
by dermestid beetles. The left forelimb and 
scapula were removed, fixed in 40% 1s0- 
propyl alcohol, and later macerated and 
stained to study the epiphyseal areas. The 
right forelimb was similarly removed and 
preserved in formalin together with the tail. 
Both structures were later X-rayed for 
epiphyseal fusion. The entire penis was re- 
moved, macerated, and the baculum stained. 
Other reproductive structures were inspected, 
and pertinent notes taken. The remaining 
portion of the carcass was preserved in 
formalin. 


B. Field Study 


Growth data on laboratory-raised individ- 
uals of a wild species would not be expected 


to be the same as on animals in their nat- 
ural habitat. Many differences exist be- 
tween the laboratory and the natural habitat, 
such as food and climatic factors. Moreover, 
the cage environment may produce condi- 
tions that affect the normal growth of the 
animal. The limitations of activity, the lack 
of extreme environmental variation, and the 
change in social patterns are difficult to 
evaluate. Thus I attempted to obtain growth 
data on known-age cotton rats in their nat- 
ural habitat by releasing and retrapping 
young cotton rats born in the laboratory (in- 
dividually marked by toe-clip). The re- 
trapped individuals were examined and re- 
leased, hopefully to be retrapped a second 
time. 
IV. RESULTS 
A. General Body Measurements 

The body length measurement was ob- 
tained by subtracting the tail length from 
the total length. I consider this computed 
measurement more reliable than either of 
the other two measurements, as portions of 
the tail are frequently lost. 

The data for weight (Fig. 1) and for body 


250 


200 


150 


Weight in Grams 


100 


50 


2 


I 525342 S266. 7 8 See Oma 18 


Age in Months 


Figure 1. Body weight when sacrificed of 
known-age cotton rats by sex. The vertical 
line indicates the range and the horizontal 
line the mean of the sample. The left line 
of each pair is the data for males, the right 
line the data for females. 


No. 2 


length (Fig. 2) are presented by sex. The 
difference between the sexes for these char- 
acters was considered significant (P==0.02). 
The sexual dimorphism of hind foot and ear 
length (Fig. 3) is not considered significant 
(P=0.3), and the data are combined for 
both sexes. 


Length in Millimeters 


fea) 34s 67 a9" 10) iM i2 18 
Age in Months 

Figure 2. Body length when sacrificed of 

known-age cotton rats by sex. (See Figure 

1 for description). 


Height and Lenath in Millimeters 


ices 4.75) 56) 7 8 9 TOMI le 18 


Age in Months 


Figure 3. Ear height and hind foot length 
when sacrificed of known-age cotton rats. 
Data are for both sexes. Upper series of 
data are for hind foot length; lower series 
of data are for ear height. The vertical 
line represents the range and the horizon- 
tal line the mean of the sample. 


While of limited value for age determina- 
tion, these data should be considered in de- 
tail as these measurements are classical mam- 
malian measurements. The measurements 
differentiate satisfactorily between one- and 
two-month-old animals, and distinguish these 
two age groups from older specimens. The 
age groups are best separated on the basis 
of body length and, to a lesser extent, by 
hind foot and ear lengths. Weight appears 


Age Determination of Cotton Rat 23 


to be least related to age and is the most 
variable measurement. 

The usefulness of any character for age 
determination depends in part on knowing 
and evaluating its variability. One possible 
variable might be the day length during the 
first few months of the cotton rat’s life, since 
this was not controlled. The body length of 
nine males and five females born between 
September 8th and 12th are compared with 
11 males and 12 females born between Janu- 
ary 11th and 14th (Fig. 4). The first group 


180 
5 
% 160 
E 
= 
£ 140 
= 
> 
5 
120 
5 
=f VES —= 
100 a7 Females== == = = 
w 


3 6 9 l2 ifs) 18 2l 24 
Age in Weeks 


Figure 4. Variation in mean growth rates 
of known-age cotton rats, depending on the 
time of the year in which the animals were 
born. 


was exposed therefore to a decreasing day 
length for three months and then to an in- 
creas ng photoperiod, the second group being 
exposed only to an increasing day length. 
The January group was consistently larger 
at each age in body length than the Septem- 
ber group. While Figure 4 shows only the 
means for the sample, the ranges of the 
measurement showed little overlap. At three 
weeks of age the means differ by 10 mm, 
while at nine weeks the differences are 14 
mm for females and 19 mm for males. At 
these two points there are no areas of over- 
lap of the range. For the males this differ- 
ence in body length is maintained until 
twenty-three weeks of age, the limit of the 
data. For the females the means appear to 
be approaching each other at this age. 

Body length is the most reliable measure- 
ment for age determination (Fig. 2). How- 
ever, the seasonal variation, whatever its 
basis, could handicap the data. Perhaps sepa- 
rate growth curves could be used during dif- 
ferent seasons, but this seems a questionable 
procedure. 

A second source of variation might be 


24 Tulane Studies in Zoology 


genetic, i.e., would growth curves determined 
by animals from one area be applicable to 
animals from another area? The only other 
study of laboratory cotton rats is that of 
Meyer and Meyer (1944). The stock for 
their colony came from Baton Rouge, Lou- 
isiana, 80 miles from the locality of my 
stock, and belong to the same subspecies 
(S. h. hispidus), The only comparable data 
presented by these authors are body weights, 
and when their growth curves are plotted 
with mine the curves are virtually contigu- 
ous. This fact does not really answer the 
question posed as to genetic variability, al- 
though the similarity of the two growth 
curves suggests the data of my study might 
be used within the range of this subspecies 
safely. 

A third question raised by the data is the 
apparent decrease in means and ranges of 
measurements at 8 or 9 months in Figures 
1, 2, and 3. Each age sample comprises only 
the measurements of the sacrificed animals. 
Thus at 8 or 9 months there is no decrease 
but only the data from smaller animals. The 
reason for these smaller animals is not at 
all clear. The best suggestion seems to be 
the season in which the specific individuals 
were born. Those animals forming the eight- 
and nine-month samples were born in No- 
vember and December, while those forming 
the younger age samples were born in Janu- 
ary through March. Photoperiod can be sug- 
gested as the cause, but the mechanism is 
only conjecture. 


Undoubtedly other factors will affect body 
weight and measurements. Sealander and 
Walker (1955) and Dunaway and Kaye 
(1964) have shown the mean body weights 
to decline during winter when depot body 
fat is being rapidly consumed and recruit- 
ment of the population is low. 


B. Pelage and Molts 


The results presented in this section are 
based primarily on observations of the dried 
pelt, with data of live animals being used as 
a check and/or elaboration. 

The pelage of cotton rats displays a re- 
markable degree of uniformity throughout 
the animal’s life. All the pelts were viewed 
at One time, but no real variations in color, 
shade, or texture could be observed except 
for very young cotton rats (one to two weeks 
old) in which the pelage was notably softer 
and composed of shorter hairs. 


Vol. 12 


The actual molting patterns or progres- 
sions are diagramed in Figure 5. Several 
specific molts can be demonstrated onto- 
genetically. The newborn cotton rat is com- 
pletely furred with short hairs somewhat 
darker than the adult. The juvenile pelage 
becomes complete within one week of age 
at which time the young cotton rat begins 
the very rapid molt to the subadult pelage. 
This molt begins in the ventral thoracic 
region. The three-week-old animal is molt- 
ing laterally. At four weeks of age the ani- 
mal is molting dorsally only. The new pel- 
age is complete between five and six weeks 
of age, and the animal is now a subadult 
(i.e, may become reproductively active but 
physically smaller than the adult body size). 
This molt is extremely constant both in pat- 
tern and duration. 

The next molt is termed the adult molt, 
since at its completion the cotton rat has 
reached adult size and the growth rate de- 
creases abruptly. This molt usually begins at 
five to six weeks of age, often while the 
previously described molt is still present 
dorsally particularly on the top of the head. 
The progression of this adult molt is the 
same as for the subadult molt except for 
duration. The first molt requires about one 
month for completion while the adult molt 
requires two and one-half to three months. 
As a practical point, these two molts can 
be distinguished by: (1) the presence of 
juvenile pelage dorsally in the subadult molt; 
(2) the adult molt occurring as a narrow 
lateral band while the subadubt molt being 
present over one-half of the body surface at 
once; (3) the small size of the animal dur- 
ing the subadult molt. 

As early as five months but usually around 
six months, the cotton rats molt again. This 
molt, very irregular both in duration and 
extent, has been termed a patch molt. My 
observations indicate that this molt follows 
the general pattern described for the pre- 
vious molts and differs in that only small 
disconnected areas are molting at any one 
time. Both the duration and precise pro- 
gression of this molt are difficult to follow, 
especially since the animal will frequently 
stop molting only to start again where it 
stopped or commence a new molt, or both. 

Further adult molts occur with increasing 
irregularity both in area and duration. Molt- 
ing is most easily observed when present 
laterally, particularly around the front limbs 


No. 2 


and on the cheeks. The molting areas are 
small and scattered, and become even more 
so as the molt progresses dorsally. I have 
presumed the typical ventral-to-dorsal pro- 
gression occurs, but definite observations are 
insufficient for a positive description due to 
the limited number of animals raised to the 
older age samples. The later adult molts ap- 
pear strongly influenced by photoperiod and, 
in the case of a few known-age females used 
as breeders, by reproduction as well. 

The adult molts need more critical study 
than could be undertaken. However, if a 
normal longevity of six to eight months is 
postulated, then the molting pattern, if 
closely examined, could be helpful for esti- 
mating the age of the cotton rat. If the 
specimen shows no molting, then the ani- 
mal is either in complete subadult pelage 
(about six weeks old) or in complete adult 
pelage (about five months old). Body length 
or weight could be used to distinguish these 
two ages. The use of the molting pattern for 
age determination of cotton rats does not 
consider environmental variations. 

Photoperiod will potentially influence the 
use of molting as an aging device, although 


nose 


lower 
jaw 


\ina eye 


front 
limb 


hind 
limb 


3 Weeks 


Age Determination of Cotton Rat 25 


the major variation seems to occur after the 
subadult-to-adult molt has been completed. 
Mohn (1958) described the development of 
“growth waves” (1e., ontogenic molts) for 
the black rat (Rattus norvegicus) which are 
virtually identical to my observations in age 
at Onset, progression, and duration. The 
similarity of these observations as well as 
those by other authors suggests that the 
first few molts (to the adult pelage) are 
more influenced by ontogeny than other fac- 
tors. Mohn also comments that the later 
(adult? ) molts are considerably more vari- 
able and the frequency and rate are retarded 
by both pregnancy and lactation. 

A microscopic examination of individual 
hairs and groups of hairs was undertaken. 
The hairs of one-month-old animals were 
distinctly shorter and were a mixture of the 
shorter juvenile hairs and the incompletely 
grown subadult hairs. Otherwise microscopic 
examination of the hair was of no value for 
age determination. 


C. Reproduction 


The condition of the external reproductive 
structures was included in the periodic ex- 


6 Weeks 2 Months 


5 Months 7 Months 


patterns of known-age cotton rats viewed from the skin side of the 


3 Months 4 Months 
Figure 5. Molt ‘ 
pelt. Darkened areas indicate areas of active molting. 


26 Tulane Studies in Zoology 


amination of the live cotton rats. For males 
the position of the testes (scrotal or ab- 
dominal) was determined. The pigmenta- 
tion and relative size of the teat and the con- 
dition of the vaginal orifice (perforate or 
imperforate ) were recorded for each female. 
Additional data were derived from an ex- 
amination of the birth dates of litters from 
known-age parents. 

The youngest age at which a rat gave birth 
was 65 days, having been impregnated by a 
litter mate. Subtracting a gestation period 
of 27 days (as determined by Meyer and 
Meyer, 1944) gives an age at conception of 
38 days. This particular individual was the 
only spring-born (February) female that 
was used for breeding purposes. All other 
data on age at first litter are from animals 
born during September and October. For 
these individuals the youngest age at which 
a female gave birth was 84 days, with con- 
ception thus occurring at 57 days. The age 
at conception of the first litter for other 
females ranged from 70-100 days, with the 
older age being more common. Meyer and 
Meyer noted one female being impregnated 
at 40 days of age and several others by 50 
days of age. These authors also noted the 
first estrus to occur at a younger age during 
the period January-through-June than dur- 
ing the period September-through-December. 

The condition of pregnancy is of value for 
age determination only to the extent that the 
investigator can determine a probable mini- 
mal age. Furthermore, nonimpregnated fe- 
males need not necessarily be less than that 
minimal age. Additionally, Odum (1955) 
and Haines (1961) have shown that the cot- 
ton rat has seasonal reproductive peaks and 
occasional periods of anestrus, especially 
during the winter. Presumably photoperiod 
affects the age at onset of reproductive ma- 
turity although other factors undoubtedly 
exist. Thus pregnancy is at best a limited 
tool for age determination. 

The earliest age at which a_ perforate 
vaginal orifice was noticed was six wecks. 
By three months all females had shown this 
condition at least once. When sacrificed, one 
two-month-old female had a distended, fluid- 
Mee uterus, a condition described by Clark 

1936) as occurring during proestrus and 
estrus. An active estrus, as determined by a 
perforate vaginal orifice or an examination 
of the uterus, might be more helpful for age 
determination than pregnancy as it occurs 


Vol. 12 


independent of male cotton rats. However, 
the condition is still influenced by season 
and, like pregnancy, is of value only for es- 
tablishing minimal age. 

Size and extent of the pigmentation of 
the teat were constant for females two 
months or older, except for pregnant and 
nursing individuals. One-month-old females 
showed no pigmentation except for the one 
female mentioned above that bred at 38 days 
of age. By two months all females showed 
some pigmentation, and by three months all 
possessed a dark-brown pigmentation of the 
teat. A week or ten days prior to the birth 
of a litter the teats become enlarged and 
change from dark-brown to black pigmen- 
tataion. The dark-brown color returns after 
weaning if the female is not pregnant. The 
size and degree of pigmentation of the teat 
suggest an expression of sexual maturity and 
activity rather than of age. 


Sexual maturity in males can be deter- 
mined by the presence of viable sperm in 
the epididymis. No sperm were seen in 
smears of the epididymis of one month and 
six-week-old males. The testes normally de- 
scend and remain in the scrotal sac at two 
weeks to one month for laboratory-raised 
young. Of the five two-month-old males, 
only two contained sperm in the smeared 
epididymis. Viable sperm were present in 
all males three months of age or older. The 
two earliest pregnancies reported above 
(conception at 38 days) were by males of 
the same age as the females. Haines (1961) 
has shown that male cotton rats vary as much 
as females seasonally, although I did not 
notice this. Whatever the variations and 
their causes, reproductive maturity in males 
is only indicative of a minimal age of per- 
haps two months and is thus of very limited 
value for age determination. 

The baculum and its digital processes were 
studied after maceration and staining. Mac- 
eration was considerably hastened by pre- 
serving the penis in 40% isopropyl alcohol. 
Stained specimens were stored in glycerine 
containing 0.5% phenol to inhibit mold. All 
bacula were measured with dial calipers. The 
total length and the height and width of 
the base were carefully examined, and char- 
acter indices were attempted. One-month- 
old animals were distinct, but all older age 
groups encompassed the same measurements. 
The staining of the bacula showed a high 


No. 2 


degree of uniformity, variations being prob- 
ably due to staining technique. 

Forty-two bacula had digital processes that 
were satisfactory for study. Of these, 18 were 
less than seven months of age and showed 
no deposition of stain in the processes and 
may thus be assumed to exhibit no ossifica- 
tion. Seven-month-old specimens show a 
small amount of stain in the tip of the 
medial process, which increases in extent 
with age. The lateral processes begin to 
show staining at nine months, also increas- 
ing with age. The extent of the staining is 
nearly complete at 12 months, showing very 
little increase at 18 months. The progression 
of the stained areas is illustrated in Figure 6. 


yd “RNS 

Nd “AN 

And “ARE 
An 4 


Figure 6. Digital processes from bacula of 
known-age cotton rats. Number at each 
group of three indicates the age. The first 
figure on the left is a ventral view of the 
median cartilage; the middle figure is a 
lateral view of the median cartilage; the 
figure on the right is a ventro-lateral view 
of a lateral cartilage. 


The value for age determination of the 
staining of the digital processes is limited 
to male animals over six months of age. In 
all probability this would be a very small 
portion of the population. If sufficient 
numbers of males with ossifying digital 
processes could be collected, some evaluation 
of the age composition of the older individ- 
uals could be made, especially if one pre- 


Age Determination of Cotton Rat 27 


sumes the same age distribution for the 
females. 
D Leeth 

Twelve measurements were made of vari- 
ous individual teeth and tooth rows. The re- 
sults were effective only to separate one- 
month-old cotton rats from all older age 
groups which remained indistinct from each 
other. 

Three subjective tooth characters became 
evident when measuring the skulls. When 
viewed laterally, the occlusal surface of the 
lower molariform teeth appears as a straight 
line for the younger animals. For the older 
individuals this view becomes more concave, 
presumably due to the grinding of the two 
tooth rows on each other (Fig. 7). Subjec- 
tive categories with numerical values were 
applied in an attempt to evaluate this uneven 
wearing. The technique did not prove suc- 
cessful and was particularly unworkable for 
very old animals. 

The second character was the differential 
wearing of the first lower molar, the pos- 
terior two thirds being ground away more 
rapidly leaving a short prominence or spike 
on the anterior third (Fig. 7,C and D). The 
prominence was categorized numerically but 
the results were similarly unproductive es- 
pecially for very old individuals which often 
lacked the prominence. 

The third character was the reentrant 
angle or groove on the lateral crown surface 
of the molar teeth. As the tooth is worn 
away, the groove decreases in length and be- 
comes more exposed. Since the size is too 
small to measure, I attempted to evaluate 
the length of the groove as the ratio (ex- 
pressed as per cent) of this length to the 
exposed crown height. This evaluation was 
only made on the first and second molars as 
the third is partially concealed by the base 
of the coronoid process. Again the char- 
acterization was not significant. The de- 
creased length of the groove is evident in 
Figure 7. 

At the age of one month only eight molars 
are visible in the cotton rat. The third molar 
(both mandibular and maxillary) has not yet 
broken the skin although the tooth is not 
covered with bone. By two months, the tooth 
has completely erupted and has attained ap- 
proximately the same height as the first and 
second molars. 

The occlusal surface is quite constant 
throughout the life of the cotton rat. The 


28 Tulane Studies n Zoology 


Sigg: 


Figure 7. Lower jaws of known-age cot- 
ton rats. A—1 month, B—3 months, C— 
6 months, D—9 months. 


changes were more difficult to evaluate than 
the three subjective categories listed above 
and thus were of even less value for age 
determination. 


E. Skeleton 


Skulls of a male and a female of each age 
group were randomly selected for a pre- 
liminary study of characters that might be 
useful for age determination, measurements 


Vol. 12 


being made with dial calipers. Over thirty 
measurements were investigated. Measure- 
ments of: 1) nasal length; 2) greatest 
zygomatic breadth; and 3) greatest width 
of the lambdoidal crest seem to be related 
to age, and were made on all skulls, as was 
the condylobasilar length. The data from 
the four measurements are summarized in 
Figures 8-11. 


For the condylobasilar length (Fig. 8) the 
data are presented separately for each sex, 
the males at each age having significantly 
longer skulls than the females (P==0.05 at 
one month of age; P==0.02 at all older ages). 
For the other three measurements ( Figs. 
9-11) the differences between the sexes were 
small although the males were uniformly 
larger. P values were as low as 0.1 in a few 
instances but for the most part were 0.3 or 
greater. The data do not warrant being 


Length in Millimeters 


3.4 5 6 7 8) 9) slomiiml2 18 
Age in Months 


| 


Figure 8. Condylobasilar length of known- 
age cotton rats by sex. (See Figure 1 for 
description. ) 


J] hl 
| 


Age in Months 


Figure 9. Nasal length of known-age cot- 
ton rats. (See Figure 3 for description.) 


Oo 


Rh 


june 


Breadth in M limeters 


Ad 


ee sses 5516 676 69) 108 I) Ie 8 
Age in Months 
Figure 10. Lambcidal breadth of known- 
age cotton rats. (See Figure 3 for descrip- 
tion.) 


Breadth in Millimeters 


i 2 Slee Gem eG Gite ee i 
Age in Months 
Figure 11. Zygomatic breadth of known- 


age cotton rats. The thinner, vertical line 
on the left of each symbol represents the 
range of the data. The heavier, vertical 
line on the right of each pair represents 
two standard deviations on either side of 
the mean, which is indicated by the horizon- 
tal line. 


separated by sex especially considering the 
small sample size. 


The measurement of the most apparent 
value for age determination is the zygomatic 
breadth (Fig. 11). For this measurement 
the standard deviation was computed and 
added to the figure as two standard devi- 
ations on either side of the mean. This 
procedure was used to determine the validity 
of the sample as the two standard deviations 
would thus represent ninety-five per cent of 
the population and provide more comparison 
than the actual ranges. 

By inspection one-month-old individuals 


Age Determination of Cotton Rat 29 


are distinct from all other groups. The two- 
month-old individuals are nearly distinct. A 
line has been added to the figure at 18.7 
mm to separate the two-month-old individ- 
uals from older specimens. The overlap of 
the data is in the standard deviation only, 
the ranges being distinct. Three- and four- 
month animals together form a group which 
is largely separable from the rest of the 
animals in this study. A second line has 
been added at 19.8 mm _ which, although 
arbitrary, separates most of the three- and 
four-month specimens from most older in- 
dividuals. 

Thus, four age groups can be identified: 
1) one-month-old individuals; 2) two- 
month-old individuals; 3) three- and four- 
month-old individuals; and 4) individuals 
five months or older. These categories have 
virtually no overlapping of the ranges. The 
sample size is undesirably small, perhaps 
accounting for a large standard deviation. 

Alexander (1960) has shown that there 
is approximately a 1.5% decrease in the 
zygomatic measurement of the muskrat as 
the skull dries. This shrinkage in cotton rats 
would amount to 0.3 mm of a zygomatic 
breadth of 20 mm. Since all skulls were 
cleaned and measured at the same time, the 
shrinkage should be uniform and the data 
still valid. Presumably standard cleaning and 
measuring techniques should be used when 
making this measurement on a population 
sample. Character indices also were com- 
puted by various combinations of the four 
measurements, but the applicability of the 
data was not increased. 

Older animals exhibit a general increase 
in the development of the ridges or crests 
of the skull. The ridges appear to attain 
most of their development by three or four 
months, although the skull still appears to 
become more massive throughout the age 
groups. However, with the exception of the 
breadth of the skull at the lambdoidal ridge, 
all measurements to evaluate this increased 
size were unsuccessful. Weighing the skulls 
only served to distinguish one-month-old in- 
dividuals as a group. Furthermore, when 
guessing the age of an individual skull by 
examination of the development of its ridges 
and its weight, I was successful only with 
one- and two-month-old individuals. Thus, 
while subjectively evident, the ridges defy 
objective measurements and are concluded 
to be of little value for age determination. 


30 Tulane Studies in Zoology 


The mandibular weight permitted the 
identification of both one- and two-month- 
old animals as groups distinct from the rest 
of the specimens. The limited value of this 
measurement does not justify the time spent 
in the careful cleaning of the mandible be- 
fore weighing. 

The forelimb was studied extensively for 
areas of epiphyseal fusion that would be 
of value for age determination. The results 
described below are a composite of both 
the maceration and X-ray data, the former 
being the more easily studied. At one month 
the distal epiphyses of the metacarpals are 
distinguished from the diaphyses by a non- 
staining band of cartilage, which by two 
months is reduced to a deeper staining 
suture line. This line becomes indistinct at 
three months and is absent at four months 
of age. 

The sesamoid bones of the metacarpal- 
phalanx joint first become apparent by stain- 
ing at three months of age, but are distinct 
from the two bones of the digit. At four 
months the sesamoids are beginning to fuse 
with the metacarpals, which process is com- 
pleted at five months of age. 

A second series of sesamoids can be seen 
at four months, at the distal end of the 
proximal phalanx. Like the first series these 
bones are fused to the proximal phalanx 
two months later at an age of six months. 

The distal epiphyses of the radius and 
ulna at one month are distinct and separated 
from the diaphyses by a clear nonstaining 
band of cartilage. For animals two months 
of age the epiphyses are separated only by 
a line lacking in stain. The epiphyseal suture 
is about one-half ossified at three months. 
The process is virtually completed at four 
months although a suture line is visible in 
all older specimens and shows very little 
change. Green (1949) also has noted the 
persistence of this suture line to older ages 
in the Norway rat. 

The proximal epiphysis of the ulna is very 
similar to the distal epiphyses of the radius 
and ulna, clearly distinct at one month and 
largely ossified to the diaphysis at four 
months of age. A suture line is similarly 
present in all older specimens. 

The acromion process of the scapula shows 
no ossification at one month of age and 
only a small distal area of stain deposition 
at two months. The amount of ossification 
gradually increases so that the process 1s 


Violet 


largely if not completely ossified at five 
months. A suture line is still visible for a 
few months, but is absent in all specimens 
nine months or older. 

The suprascapular cartilage is also un- 
stained at one month of age. At two months 
a small area of staining appears at the corner 
of the glenoid and vertebral borders of the 
scapula. By three months the suprascapular 
cartilage is ossified about one half its length, 
but a narrow stain-free area separates the 
ossifying cartilage from the scapula. At five 
months of age the cartilage is largely oss1- 
fied, and only at this time does the supra- 
scapular cartilage begin to fuse to the scap- 
ula. This later process continues slowly and 
is not complete even in the twelve-month 
animals. 

The ossification processes are not all com- 
plete at six months, but at this age the 
changes are very slow and irregular. These 
later stages of ossification and fusion are of 
very limited value for age determination 
and are not discussed. All the described areas 
of ossification are summarized in Figure 8. 
Other epiphyseal areas exist in the forelimb, 
but these are either difficult to distinguish, 
such as the epiphyseal areas of the humerus, 
or proceed too rapidly to be diagnostic, such 
as is seen in the epiphyses of the phalanges. 

The tail also was X-rayed to study the 
degree of ossification and fusion of the 
intervertebral discs. This procedure was in- 
vestigated as the tail can be X-rayed easily 
on a live, anesthetized animal where an ex- 
amination without injury is highly desirable. 

For the younger animals the caudal inter- 
vertebral discs are largely unossified to the 
centra of the vertebrae. Those that are 
nearest the pelvis ossify first. The degree of 
ossification increases with increasing age of 
the specimen, although it is never complete. 
Even in the twelve-month-old specimens the 
last few (three to six) discs remain quite 
distinct. The major difficulty in evaluating 
the data is deciding which discs have begun 
to show ossification in order to produce 
numerical or even reasonably objective data. 
No satisfactory method was found. The 
problem was compounded due to the X-ray 
film used and its inability to produce a suf- 
ficiently sharp outline of the structure. 

The use of epiphyseal fusion gives promise 
as an aging device. While the best data are 
derived from the examination of macerated 
material, the use of X-rays is encouraging 


No. 2 


and should be investigated further. If mac- 
erated limbs are used, a good estimation of 
age can be made by the examination of the 
seven areas of bone development (Fig. 12). 


F. Lens Weight 


All lens weights discussed are the com- 
bined weight of both lenses. The technique 
employed here is that described by Lord 
(1959). Each age group was examined for 
sexual dimorphism. Except for the ten- 
month-old group discussed below, no sig- 
nificant differences exist between the sexes 
(P>0.3). The data for both sexes are 
therefore considered as a single sample for 
each age, the larger sample size permitting 
a better mathematical comparison of the age 
groups. Lord likewise noted no differences 
between males and females and considered 
both sexes as a single sample. 

The ranges and means for the data are 
presented in Figure 13. The standard devi- 
ation has been computed for each age group 
and added to the figure as two standard devi- 
ations on either side of the mean. This 
method of evaluation is especially justified 
since the standard deviations exceed the 
range of most samples. 


2 


D Epiphysis, 


Separate Fusing 


Metacarpal 


Sesamoid, 


Metacarpal 


Sesamoid, 
P. Phalanx 


D. Epiphysis, 
Radius, Ulna 


Fusing 


Nonstaining 5 Stained 


Acromion 


Process 


Figure 12. 
age in months. 


3 Stained] = Stained 


= Stained 5 Stained 


Summary of data on epiphyseal fusion. The numbers at the top indicate the 


Age Determination of Cotton Rat 31 


The one-month-old sample is quite dis- 
tinct. The two-month-old sample is nearly 
so, a small overlap of the standard deviations 
occurring between the two- and three-month 
samples. Animals up to three months, there- 
fore, could be quite correctly aged by this 
technique. For all older age groups, both the 
range of the sample and the area covered 
by the two standard deviations show at least 
some contiguity, especially for those groups 
six months or older. 

Older age groups might be distinguished 
by making arbitrary weight values to sepa- 
rate them. Accordingly, horizontal lines have 
been added to Figure 13 at 25 and 33 mg. 
This permits isolation of a four- and a five- 
month-old age group from the three-month 
age group and the age group six months or 
older. Thus a total of five age classes can 
be established. Of the 62 individuals in the 
one- through six-month-old age groups, only 
three, or less than 5%, thus fall into incor- 
rect classes. Therefore, the dry lens weight 
would appear to be a very satisfactory tech- 
nique for age determination. 

For the successful application of any aging 
technique, one should be aware of possible 
variations and their causes. The 10-, 11-, 


Suture Line Visible 


Fused 


Suture Line Visible 


16%} I) 


Fusing to Scapula 


Wo 
ho 


Weight in Milligrams 


i ¥2 


SA SG 7 eo io i iB 
Age in Months 

Figure 18. Dry lens weight of known-age 

cotton rats. (See Figure 11 for description. ) 


and 12-month-old samples offer some in- 
sights to the problem. The limits of the two 
standard deviations of the 10-month sample 
considerably exceeded the observed range, 
admittedly large itself. The individuals con- 
stituting this sample fall into two groups: 
one of six females whose lens weights range 
from 35.6-37.8 mg, and a second group of 
three males whose lens weights ranged from 
43.9-44.3 mg. This is the only age group 
where distinct differences occur between the 
sexes. Perhaps a more reasonable explana- 
tion is that the females were not autopsied 
until several days after being sacrificed, al- 


though the specimens were frozen. Mont- 
gomery (1963) has shown that raccoon 


lenses lose weight after being frozen for sev- 
eral days before autopsy. 

For the 1l-month-old sample, one indi- 
vidual born in May and sacrificed the fol- 
lowing April had a lens weight of 36.7 mg. 
The remaining individuals of this sample 
were born in September and sacrificed the 
following August. These individuals had 
lens weights ranging from 40.4 to 43.2 mg. 
The 12-month-old samples contained one 
group of seven individuals born and _sacri- 
ficed in May whose lens weights ranged 


Tulane Studies n Zoology 


VolAi2 


from 36.2 to 39.4 mg. The remaining four 
individuals of the sample were born and 
sacrificed in September and had lens weights 
of 39.6 to 43.8 mg. None of the specimens 
were frozen prior to autopsy. An explanation 
of the differences in weight might be vari- 
ation induced by the day length since the 
animals, born in different seasons, were sub- 
jected to the normal day length throughout 
this study. Also, since the animals were 
from several different litters this range of 
weight might simply indicate normal vari- 
ation in the older animals. 


G. Field Study 


The last phase of this study was an at- 
tempt to obtain accurate growth data from 
the natural habitat to be compared to the 
laboratory-derived growth curves which 
could then be evaluated and adjusted. An 
old field habitat was selected for releasing 
four-week-old laboratory-raised animals. The 
area had been trapped intermittently over 
a period of two years and was known to be 
suitable for cotton rats. For two months 
before releasing the young animals I made 
several trips to the area to trap out as much 
of the existing small mammal fauna as pos- 
sible, reducing competition for the young 
cotton rats. During the retrapping period 
following release of the young, only one 
nonmarked cotton rat was collected. 

Each cotton rat to be released was toe- 
clipped for identification when weaned. 
Three or four cotton rats from the same litter 
were then placed in a new cage. In place 
of the usual tin-can nesting facilities the 
animals were provided with a wooden nest 
box approximately 6 x 6 x 4 inches high. 
A 2 x 2 inch opening was provided with a 
cover that could be closed quickly with the 
cotton rats inside. The nest box was trans- 
ported to the release area, the cover opened, 
and the animals left with an available nest 
to which they might be accustomed. A lib- 
eral supply of food was also placed in the 
nest box. I had hoped that some individuals 
would continue to use this shelter and thus 
facilitate their recapture. Many of the nest 
boxes appeared to be inhabited as grass and 
cuttings were incorporated into the nest box 
cotton. However, only one cotton rat was 
ever found in the nest box and this indi- 
vidual escaped before the opening could be 
covered. A total of 96 rats were released 
from March 25 to June 5, 1961 


No. 2 


During May the release area was ex- 
haustively retrapped on three occasions with 
collapsible Sherman live traps. Approxi- 
mately 200 traps were set each of the seven 
nights involved. The release area was also 
live-trapped in mid-June for five nights con- 
tinuously with 240 traps per night, prior to 
which heavy rains had inundated the release 
area. No cotton rats or any other small mam- 
mals were collected during the latter period. 
The field project was terminated at this 
time for lack of additional young available 
for release. 

Cotton rats trapped in May were ether- 
ized, weighed, and measured, and examined 
for molting and reproductive status. They 
were then allowed to recover for 30 minutes 
and released at the same location where they 
were trapped. Of the 96 rats released, 12 
were recaptured from one to four times for 
a total of 23 recaptures. Four individuals 
died in the live traps, presumably from the 
high temperature due to direct sunlight on 
the traps and from attacks by fire ants. The 
remains of the four that died were autopsied 
as far as possible. The date on these four 
animals are given in Table 2. 


The weights and body lengths of all re- 
trapped cotton rats are plotted in Figures 
14 and 15. If an individual was retrapped 
on several consecutive days, only the first 
day is plotted. Two individuals were re- 
captured a second time, 22 days after their 
first recapture. These points are connected 
with a line for identification. 


As expected, weight increase was much 
slower in the field than in the laboratory. 
The lines on Figure 14 represent the m2zn2- 
mum weight of the monthly laboratory 
sample of each sex. The mean weight was 
so much greater that plotting it on the chart 
would have had no value for comparison. 


Age Determination of Cotton Rat 


Uo 
Wo 


4 5 6 7 8 9 10 {I 
Age in Weeks 


Figure 14. Body weights of released known- 
age cotton rats. The heavy line represents 
the minimum monthly weights from Figure 
1 (upper line for males; lower line for 
females). The thin lines connect data for 
the same individual. 


The difference between the laboratory and 
field studies probably is due to increased 
activity in search for food—food that also 
is less likely than the laboratory diet to be 
accumulated as body fat. Possibly the stress 
induced by being released into an unfamiliar 
and competitive habitat and/or being in the 
live-trap for extended periods may have af- 
fected the body weight. Animals recaptured 
on successive days showed weight losses 
from previous days of up to five grams. The 
information on body weights is too limited 
to construct a growth curve of wild animals. 
The data do strongly suggest that laboratory 
weights are of little use for age determina- 
tion of wild individuals. 


The body length measurements are plotted 
in Figure 15. The lines in this figure repre- 
sent the average body length of each monthly 
sample. The field data appear to be quite 
consistent with the laboratory data, and sub- 
stantiate the idea that the greater body 


TABLE 2. 
Data on released animals that died in the live traps. Skull measurements in millimeters; 
lens weights in milligrams. 


Animal No. 356 
Sex m 

Age (days) 85 
Condylobasilar length 34.0 
Nasal length Def 
Lambdoidal breadth 13.6 
Zygomatic breadth 18.8 
Lens weight Dione 


382 426 445 
if f f 
75 45 D5 

32.6 30.5 32.4 

12.1 Abe 12.5 

13.3 13.0 13.2 

18.4 17.6 18.0 
= 13.4 z 


* Data not available 


34 Tulane Studies n Zoology 


° 


160 


150 


& 
ro) 


130 


Length in Millimeters 


120 


10 


Age in Weeks 


Figure 15. Body length of released, known- 
age cotton rats. The heavy lines represent 
the mean body lengths from Figure 2 (up- 
per line for males; lower line for females). 
The thin lines connect data for the same 
individual. 


weights of laboratory animals reflect a 
greater amount of fat and not larger size. 
On the basis of these limited data, body 
length appears to be a useful method for 
age determination. 

Five cotton rats were found to be molting 
when recaptured. Two individuals (33 and 
34 days old) were completing the subadult 
molt. Two others (61 and 75 days old) 
were in the earlier stages of the adult molt. 
A single recapture at 84 days of age was 
molting dorsally, thus completing the adult 
molt. Five individuals captured at 43-47 
days of age were not molting. Presumably 
they were in complete subadult pelage and 
would shortly begin to molt to the adult 
pelage. The cotton rat examined at 96 days 
was not molting. The individual molting 
data of the released animals coincide well 
with the observed laboratory data except 
that the subadult-to-adult molt may begin 
somewhat later and end somewhat earlier. 
With more field studies and an increased 
understanding of seasonal variation, the 
molting pattern for age determination could 
possibly be developed to a high degree. 

The reproductive data are limited. One 
male died in the trap (age 84 days). A 
smear of the testis and epididymis was nega- 
tive but this is attributed to the carcass 
being severely damaged by fire ants and the 
length of time between death and micro- 
scopic examination. All males when recap- 
tured had the testes in the scrotal position. 

One female captured at 96 days of age 
had considerably enlarged teats and was 


Vol. 12 


lactating. The vaginal orifice was imper- 
forate which suggests that parturition had 
occurred one or two days previous to cap- 
ture. With a normal gestation period this 
female probably mated at about 65 days of 
age. This single example of reproductive 
activity of a released female agrees well with 
the laboratory data. The reproductive tracts 
of the three females that died in the live 
traps did not show any indication of repro- 
ductive activity. 


The teeth of the four released cotton rats 
that died in the traps showed the most dra- 
matic difference from the laboratory study. 
Staining of the teeth, presumably due to the 
diet, is very marked. The teeth are consider- 
ably more worn than laboratory individuals 
of the same age. Using laboratory tooth 
wear as a criterion for age determination 
produces an estimate two-to-four months 
older than the actual age. Since tooth wear 
is more rapid in the natural habitat, this 
character might be used successfully for 
aging, as more variability would be present 
and thus more stages of wear that possibly 
would reflect the animal’s age. 

The skeletal characteristics of the released 
cotton rats compare well with the laboratory 
data. The skull measurements are listed in 
Table 2. The condylobasilar and nasal 
lengths both fall in the lower range of the 
known-age measurements. The lambdoidal 
breadth and the zygomatic width show very 
satisfactory agreement with the laboratory 
data. A good age estimation can be obtained 
on the basis of these two measurements.. 

The characteristics of the stained forelimb 
are in consistent agreement with the labora- 
tory data. The metacarpal and phalangeal 
epiphyses, the distal epihyses of the radius 
and ulna, the proximal epiphyses of the 
ulna, and the ossification of the acromion 
process and the suprascapular cartilage are 
all in close agreement with the laboratory 
data. These limbs were examined initially 
without the knowledge of the specimen’s 
exact age. The 45-, 55-, and 75-day-old 
specimens were all estimated to be “about 
two months” while the 85-day-old individual 
was estimated to be “three months.” These 
estimations appear to be as accurate an 
estimation as could be made with any char- 
acter. 

The lens weights of only two of the four 
dead known-age individuals were in satis- 
factory condition for study. The eyes of the 


| 


No. 2 


others were dried out and partially eaten by 
ants. As can be seen by comparing the lens 
weight from Table 2 with those in Figure 
13, the data from the released cotton rats 
fit the laboratory data quite satisfactorily. 


V. DISCUSSION AND CONCLUSIONS 


When considering the reliability of age 
determination based upon laboratory data, 
two points must be kept in mind. First, ani- 
mals are not found in month-old groups but 
form a continuum of all ages. Thus, while 
one may attempt to assign an animal to a 
certain age group one does so with the 
knowledge that the age of the animal is 
being approximated only. The second point 
is estimating age from a live or a dead ani- 

mal. In a live-trap study one must determine 
the age and then release the animals un- 
harmed. Such a procedure limits the number 
of characters that can be employed. The 
present study was based largely upon the 
interpretation of characters from dead ani- 
mals. I presumed that some dead-animal 
characteristics could be adapted to evaluate 
living cotton rats. One possible adaptation 
would be the use of X-raying in place of the 
maceration and staining technique. 

From an examination of the data that 
have been presented it appears that age 
determination can be accomplished best for 
animals up to six months of age by a com- 
bination of several characters. Age determi- 
nation of older cotton rats appear virtually 
impossible other than to indicate an indi- 
vidual as being over six months of age. 
Precisely what age cotton rats may attain in 
their natural habitat is, of course, unknown. 
Some information on this topic has been 
presented by Odum (1955), who stated that 
an animal once trapped was never retrapped 
more than six months later. Assuming such 
an individual to be a month old or more 
when initially trapped, its maximum age 
when retrapped would probably not exceed 
seven to ten months. In a live-trapping study 
of the cotton rat in Louisiana in which I 
participated, cotton rats were never retrapped 
more than four months after the initial trap- 
ping. Recently Dunaway and Kaye (1964) 
did note two wild cotton rats approximately 
10 and 11 months of age. It is not known 
how many other rats attained such an age. 

The techniques developed in this study 
are felt to be satisfactory for estimating the 
age of wild cotton rats throughout the greater 


Age Determination of Cotton Rat 35 


portion of their presumed life expectancy. 
However, any attempt to estimate age should 
be based on several characters to minimize 
error. The most reliable characters are sum- 
marized in the following two paragraphs. 

The computed body-length measurement 
is rapidly collected and is satisfactory to sepa- 
rate animals up to three months of age from 
all other animals of the population. Molting 
might also be used to distinguish the younger 
age categories, although the distinctions are 
less specific than body length, and the pro- 
cess is more easily studied from the skin 
side of the pelt. The molting pattern con- 
tinues to change fairly regularly in the labo- 
ratory specimens, but the information is 
probably inadequate for use as a critical age- 
determining characteristic, as molting has 
been shown in other rodents to vary with 
the seasons of the year. This particular char- 
acter definitely should be studied in more 
detail under more varied laboratory condi- 
tions and in the natural habitat. 


Epiphyseal ossification can be determined 
on a dead animal by maceration and stain- 
ing. By comparing the several ossification 
areas, one can establish the approximate age 
of an animal to six months of age. For a live 
animal, epiphyseal ossification might be 
studied by X-raying the limb of an anesthe- 
tized animal. This character may have con- 
siderable advantage as an age-estimating 
technique, as ossification processes seem to 
proceed at a fairly constant rate and _ pre- 
sumably are not as subject to environmental 
variation as are body weight and molting. 
One additional charatcer that might be de- 
veloped for determining the age of a live 
cotton rat is the measurement of the zygo- 
matic breadth. This character was studied 
only on clean skulls but proved quite ac- 
curate for estimating age. Since the amount 
of flesh covering the zygomatic arch of the 
live animal is quite limited, this measure- 
ment might be adapted for estimating age. 
The lens weight data are very useful for age 
determination. There is no clear separation 
of the four- and five-month-old animals, but 
these two ages are distinguishable from all 
younger age groups and from all older ani- 
mals. As the moment nothing is known of 
the factors, other than freezing, that may 
cause variation in the lens weight. Thus by 
a combination of the above techniques, one 
should be ab!e to closely approximate the 


2 


age of a given animal based upon the labo- 
ratory data. 


One very difficult problem to evaluate is 
the difference between growth of a labora- 
tory specimen and growth of a wild spect- 
men in its natural habitat. That such a dif- 
ference exists is easily shown by the fact 
that the laboratory cotton rats used in this 
study were considerably heavier than their 
counterparts released in the field at an age 
of 4 weeks. However, this may be only part 
of the picture. Unknown and impossible to 
evaluate is the effect of preweaning growth 
on the cotton rat before it is released. All 
cotton rats, prior to release, recetved what 
might be considered an adequate if not 
optimal diet. Presumably by this time the 
subsequent growth pattern has been largely 
determined. Similarly difficult is the prob- 
lem of evaluating the health and nutrition 
of the female cotton rat prior to conception. 
A female in good health could be expected 
to produce healthier young than a female 
in poor health. Thus not only the early pre- 
weaning growth but even the prenatal de- 
velopment of the animals that were released 
was undoubtedly affected by the laboratory 
environment. One possible mechanism for 
evaluating sucn changes would be to collect 
pregnant cotton rats from the field and al- 
low them to have their litters in the labora- 
tory. Immediately after birth the animals 
could be toe-clipped, and then the female 
and her litter released into the natural en- 
vironment, possibly in a large enclosure. 
Dunaway and Kaye (1964)  toe-clipped 
young cotton rats born in live traps. Pre- 
sumably these individuals are the known-age 
animals they discuss. This method is the 
best way of obtaining known-age animals in 
their hab‘tat, although perhaps limited in 
numbers of individuals. 

Several studies have attempted to esti- 
mate the age of the cotton rat. Erickson 

1949) classified each individual as either 
immature or adult but did not give any 
basis for these age classes. Since the basic 
purposes of the study were calculations of 
movement and density, age determination 
was not particularly important. 

Similarly, Stickel and Stickel (1949) 
studied the home range of the cotton rat in 
Texas. They recognized four age Classes 
based primarily on size and breeding condi- 
tion. Only approximate body-length meas- 
urements were taken, and these were not 


36 Tulane Studies n Zoology 


Well, i 


listed by the authors. The age classes were 
thus rather subjectively determined. Their 
two youngest age Classes probably correspond 
to one- and two-month old animals as used 
in this study. 


Sealander and Walker (1955) conducted 
a study of the cotton rat in northeastern 
Arkansas. Age classes were initially defined 
on the basis of actual or potential reproduc- 
tion. Thirty days was considered the age at 
which cotton rats might begin breeding. 
The laboratory growth data of Meyer and 
Meyer (1944) were then employed to form 
weight limits to each age class. The age 
classes were subadult, 10 to 29 days; young 
adult, 30 to 50 days; old adult, 51 to 250 
days. On the basis of the age classes as 
determined by using body weight, these 
authors found an age distribution during the 
late winter and early spring that indicated 
a high percentage of young individuals in 
population. This, in spite of the fact 

hat breeding had ended the previous No- 
ae and had not yet resumed. Thus 
weight used as an age criterion did not pro- 
duce an age distribution that agreed with 
the field data. These authors also noted that 
considerable body fat accumulated by the 
cotton rats in November and December, 
declined drastically in January and February 
to about 60% of the peak December value, 
and disappeared in April. Presumably this 
body fat is used as an energy source during 
the period of its decline. Thus, while the 
animals are actually becoming older they are 
losing weight, a fact which would place ani- 
mals in younger age categories. In theory, 
weight might be used as an aging technique 
during the severe winter period if one could 
take into consideration the probable weight 
loss in each individual at this time. How- 
ever, it would be incorrect to assume that 
the same rate of body weight decline is 
present during each winter. 

Odum ( 1955) concurrently studying cot- 
ton rat Fe ater over a period of 11 years, 
presents data that may give a truer picture 
of the normal weight ca He captured a 
15-gm female on June 6, 1949. On the basis 
of an average birth weight of 7 gm and a 
gain of 1 gm a day (Svihla, 1929; Meyer 
and Meyer, 1944), the above individual was 
adjudged to be a week old when captured. 
It was recaptured on August 21, at a pre- 
sumed age of 159 days and a weight of 96 
gm. A second female weighed 74.5 gm on 


No. 2 
August 21, and two and one-half months 
later, on November 9, weighed 103 gm. 


Judging from my release records, this sec- 
ond female was two to three months old 
when first caught and, therefore, about five 
months old at the weight of 103 gm. While 
limited, the data do give some idea of the 
rate of weight gain by wild cotton rats. 
According to the weight limits of the age 
categories employed by Sealander and Walk- 
er, these two females would have been classi- 
fied as young adults (age 30-50 days). 
Odum’s study of cotton rat populations 
was based largely on spring (May) and fall 
(November) trapping. The primary pur- 
pose of his study was to follow the periodic 
changes in population density. The trap- 
ping program employed served the purpose 
well, as Odum’s methods avoided the prob- 
lematic period of winter weight loss. 
Dunaway and Kaye (1964) mention a 
male and two female cotton rats weighing 
103, 95, and 101 gm, respectively, at an age 
of 104 days when trapped in November. 
A male and a female 119 days of age when 
captured in February weighed only 88 and 
77 gm, respectively, however, and a 117 
day old male weighed only 75 gm at this 
time. Also, a female, age unknown, weighed 
62 gm in September, 87 gm in November, 
but only 84 gm in February. In addition to 
emphasizing the severe effects of winter, the 
data point out the impossibility of using 
laboratory weight for age estimation. The 
three 314-month-old cotton rats trapped in 
November fall in the weight range of 2 
month old laboratory rats. Using Odum’s 
(1955) criteria, these animals would have 
been placed in the 2-to-5-month-old category. 
The information on growth rates and re- 
productive activity of known-age individuals 
in the natural habitat is too limited for spe- 
cific conclusions. However, where available, 
data from cotton rats released in the present 
study either show close agreement with the 
laboratory data or else give indication that 
the laboratory data might be modified to 
allow for an adequate age estimation. Body 
weight is a useful age-determining technique 
at certain seasons of the year, but should not 
be employed during the period January- 
through-April except with extreme caution. 
The other techniques described in this study 
should be more useful than weight for age 
determination, especially during the winter. 
Finite evaluation of age-determining tech- 


Age Determination of Cotton Rat oy 


niques should be based on releasing and re- 
trapping young known-age individuals at all 
seasons of the year. 


VI. ACKNOWLEDGEMENTS 

I wish to express my sincere appreciation 
to the following people: Dr. Norman C. 
Negus under whose direction this study was 
carried out; Robert C. Feuer and Dan Gold- 
berg for timely assistance in the laboratory 
and field; and my wife for patience, en- 
couragement, and assistance in all phases of 
this study. 


VII. REFERENCES CITED 


ALEXANDER, MAURICE M. 1958. The place of 
aging in wildlife management. Amer. 
Sct. 46: 123-137. 

. 1960. Shrinkage of musk- 

‘rat skulls in “relation to aging. J. Wildl. 
Mgmt. 24: 326-329. 

CLARK, RENE H. 1936. The estrous cycle 


of the cotton rat. Contr. Lab. Vert. Ge- 
netics. No. 2. 2 pp. 
DUNAWAY, P. B., and S. V. KAYE 1964. 


Weights of cotton rats in relation to sea- 
son, breeding and environmental radio- 
active contamination. Am. Midland Nat- 
uralist, 71: 141-155. 


ERICKSON, ARNOLD B. 1949. Summer popu- 
lations and movements of the cotton rat 
and other rodents on the Savannah River 
Refuge. J. Mammal. 30: 133-140. 


GREEN, EUNICE C. 1949. Gross anatomy. 
In: The Rat in Laboratory Investiga- 
tions. Edmond J. Farris and John G. 
Griffith, Jr., editors. Second edition. J. 
B. Lippincott Co., Philadelphia, i-xiv; 
les 

HAINES, HowArp 1961. Seasonal changes 
in the reproductive organs of the cotton 
rat, Sigmodon hispidus. Texas J. Sci., 
13: 219-230. 

cae CHARLES E. 1958. The rate of devel- 
opment of Sigmodon hispidus as com- 
pared with some other rodents. Trans. 
Kentucky Acad. Sci., 19: 25-27. 

Lorp, RExForD D., JR. 1959. The lens as an 
indicator of eS an cottontail rabbits. 
J. Wildl. Mgmt., 23: 358-360. 


McINTIRE, J. M., B. G. SCHWEIGERT, and 
C. H. ELVEHJEM 1944. The nutrition of 
the cotton rat Sigmodon hispidus hispi- 
dus. J. Nutrition, 27: 1-9. 


Meyer, D. B., and MARTHA MarsH 19438. 
Development and management of a cot- 
ton rat colony. Am. J. Publ. Health, 33: 
697-700. 

MEYER, B. J.,. and R. K. Meyer 1944. Growth 
and reproduction of the cotton rat Sig- 
modon hispidus hispidus under laboratory 
conditions. J. Mammal., 25: 107-129. 


38 Tulane Studies n Zoology 


MoHN, MELVIN P. 1958. The effects of dif- 
ferent hormonal states on the growth of 
hair in rats. In: The Biology of Hair 
Growth, pp. 335-398. William Montagna 
and Richard A. Ellis, editors. Academic 
Press Inc., New York. i-xvii, 1-520. 

MONTGOMERY, G. G. 1963. Freezing, decom- 
position and raccoon lens weight. J. 
Wildl. Mgmt., 27: 481-483. 

OpUM, EUGENE P. 1955. An eleven year 
history of a Sigmodon population. J. 
Mammal., 36: 368-378. 


RABASA, S. L. 1952. Growth rate of the 


Vol. 12 


white rat in relation to the number per 
cage. Physiol. Zool., 25: 98-108. 

SEALANDER, JOHN A., JR., and BARRY Q. 
WALKER 1955. A study of the cotton rat 
in northwestern Arkansas. Proc. Arkan- 
sas Acad. Sci., 8: 153-162. 

STICKEL, LUCILE F. and WILLIAM H. STICK- 
EL 1949. A Sigmodon and Baiomys popu- 
lation in ungrazed and unburned Texas 
prairie. J. Mammal. 30: 141-150. 

SvIHLA, ARTHUR 1929. Life history notes 
on Sigmodon hispidus hispidus. J. Mam- 
mal., 10: 252-253. 


DIGENETIC TREMATODES OF MARINE FISHES FROM 
APALACHEE BAY, GULF OF MEXICO 


FUAD M. NAHHAS* 


and 
ROBERT B. SHORT, 
Department of Biological Sciences, 
Florida State University, 
Tallahassee, Florida 


CONTENTS 


F ABSTRACT ee 39 
I]. ACKNOWLEDGMENTS __ Pee a ae 39 
Li IN ERODUGTION AND METHODSS 2... ee es 40 
IV. DESCRIPTION AND DISCUSSION OF SPECIES___........--------------_- ee. ae a eA) 
Bamilly A porocotyiidde 2. €2 oa. i ee een eee 40 
Family Bucephalidae__ Le sl 4O 
Family Fellodistomatidae_.._____»_»______ E 4] 
Family Haplosplanchnidae 4l 
HaniliysGoroodenidde: 2. ests 2a Pi aed ee Se ee ee 2 eee 41 
Hanillys@ pechclidge sn oe ke ee ee ee 41 
amtivsepocteadiicac si. sa aks waar ies ne ls ue meer ens ee) oe ee 42 
amily Gryprosenimidae sa 2 eee eee 
anally Acanthocolpidata< sess eee en ee A eee a Se eee 
Family Hemiutidae-22. = 2 is eee A CS oe eS asia 1 ee A) 
RannilyeSclerodistomidae 2: 2s) a ee ee ee ees 

By arc EIMAIN ACAI 2 an ne sR nee RT eee a See Ee eee Lea ee 48 
Rit SALPHABERICAT: HOST=-PARASITE LIST. 2.25.2 2) en es 48 
VIL. List OF FISHES NEGATIVE FOR TREMATODES....._..--_--_ 49 
ARUP ERENCES CITED: ss ok © ae Oe ee ee ee 49 


I. ABSTRACT 


Forty-eight species of Digenea are 
reported from 43 species of fishes from 
Apalachee Bay, Florida. Three new 
species are described: Genitocotyle ca- 
blei (Opecoelidae), Lepocreadium bre- 
voortiae (Lepocreadiidae) and Pseudo- 
acanthostomum floridensis (Cryptogo- 
nimidae). Fourteen new locality rec- 
ords bring to 109 the species of Digenea 
known from Tampa Bay and the north- 


* Present address: Department of Bio- 
logical Sciences, University of the Pacific, 
Stockton, California. 


ern Gulf: 27 species from the Texas 
coast, 50 from Louisiana, 16 from Mis- 
sissippi, 31 from Tampa and Boca Cie- 
ga Bays, and 48 from Apalachee Bay. 


Il. ACKNOWLEDGMENTS 


Thanks are due a number of people, par- 
ticularly Professor Ralph W. Yerger for the 
identification and nomenclature of fishes, 
and to Mr. Theodore Booden and Mr. Edwin 
Powell for assistance in the collection of 
material. The authors also wish to acknowIl- 
edge the financial support of the Institute of 


EDITORIAL COMMITTEE FOR THIS PAPER: 


RAYMOND M. CABLE, Professor of Zoology, Department of Biological Sciences, 
Purdue University, Lafayette, Indiana 


HAROLD W. MANTER, Professor of Zoology, Department of Zoology and Physiology, 
University of Nebraska, Lincoln, Nebraska 


FRANKLIN SOGANDARES-BERNAL, Associate Professor of Zoology, Department of 


Zoology, Tulane University, New Orleans, Louisiana 


aby 


40 Tulane Studies n Zoology 


Molecular Biophysics of the Florida State 
University during residence of the first 
author as a postdoctoral fellow in the De- 
partment of Biological Sciences. 


Ill. INTRODUCTION AND METHODS 


Work on the adult digenetic trematodes 
of marine fishes of the Gulf of Mexico has 
been summarized or reviewed by Manter 
(1954) and Sparks (1960). To date 190 
species are known from Tortugas compared 
with 87 from other parts of the Gulf: Tampa 
and Boca Ciega Bays (31), Mississippi (16), 
Louisiana (50), and Texas (27). In con- 
trast, only four species have been reported 
from Apalachee Bay in the northeastern part 
of the Gulf. Short (1953, 1954) reported 
two new species of aporocotylids, Kruse 
(1959) redescribed Opecoeloides fimbriatus 
(Linton, 1934) Sogandares-Bernal and Hut- 
ton, 1959, and Riggin and Sparks (1962) 
described a new bucephalid. The present 
paper adds 44 species to the Apalachee Bay; 
some are reported for the first time from the 
Gulf of Mexico. Not included are six spe- 
cies of monorchiids and zoogonids which 
will be reported elsewhere. The present sur- 
vey was conducted mainly over a 10-week 
period during the summers of 1963 and 
1964, and consists of the examination of 
more than 300 individuals representing 63 
species of fishes, taken from Alligator Har- 
bor, Mud Cove, Dog Island Reef, off St. 
Marks light house, and off St. George Island 
in the Apalachee Bay. The fishes were ob- 
tained by several methods including traps, 
nets, line, and the use of rotenone. Hosts 
were examined shortly after their death; in 
a few instances their viscera were kept in 
0.7% saline for less than six hours in jars 
placed on ice. The worms were washed in 
saline, studied alive whenever time per- 
mitted, and fixed in Alcohol-Formalin-Acetic 
acid (A.F.A.) under light cover slip pressure. 
An attempt was made to relax some of the 
trematodes in chloretone before fixation, but 
the results were not satisfactory, particularly 
in the case of the hemiurids. The specimens 
were stained with either Semichon’s carmine, 
Harris haematoxylin, or Ehrlich’s acid hae- 
matoxylin, dehydrated in a graded series of 
ethyl alcohol, cleared in  terpineol, and 
mounted in damar. Figures were drawn 
with the aid of a microprojector or a camera 
lucida, except for Figure 5 which was traced 
from a photograph. Measurements are in 


Vol. 12 


millimeters except where indicated other- 
wise. All host names are those used in 
American Fisheries Society Special Publica- 
tion No. 2, 1960, “A list of Common and 
Scientific Names of Fishes from the United 
States and Canada.” Holotypes of new spe- 
cies as well as specimens of some known 
ones are deposited in the U. S. National 
Museum Helminthological Collection. An 
asterisk indicates a new host record; two 
asterisks, a new locality record for the north- 
ern Gulf. 


IV. DESCRIPTION AND DISCUSSION OF 
SPECIES 


FAMILY APOROCOTYLIDAE Odhner, 
1912 


Cardicola laruet Short, 1953 
Hosts: Cynoscion arenarius; C. nebulosus 
Site: heart 
Localities: Alligator Harbor; St. George 
Island 


Selachohemecus olsoni Short, 1954 
Host: Scoliodon terrae-novae 
Site: heart 
Locality: Alligator Harbor 
This species was not found in the present 
study but is listed to give a more complete 
record of adult trematodes of the area. 


FAMILY BUCEPHALIDAE Poche, 1907 


Bucephalus varicus Manter, 1940 
Hosts: Caranx crysos; C. hippos 
Site: ceca 
Localities: Alligator Harbor; Dog Island 
Reef 


Bucephaloides arcuatus (Linton, 1900) 
Hopkins, 1954** 

Synonyms: Gasterostomum arcuatum Lin- 

ton, 1900; Gasterostomum sp. Linton, 
1900; Bucephalopsis arcuatus (Linton) Eck- 
man, 1932 

Hosts: *Pomatomus saltatrix; Scombero- 
morus maculatus 

Site: intestine 

Locality: Dog Island Reef 

Deposited specimen: US.N.M. No. 60080 


Bucephaloides bennetti Hopkins & Sparks, 
1958 

Host: Paralichthys albigutta 

Site: intestine 

Locality: Alligator Harbor 


No. 2 


Bucephaloides caecorum Hopkins, 1956 
Host: Batrdiella chrysura 

Sites: ceca and intestine 

Locality: Alligator Harbor 


Bucephaloides megacirrus Riggin & Sparks, 
1962 
Host: Sciaenops ocellata 
Site: intestine 
Locality: Alligator Harbor 


Rhipidocotyle baculum (Linton, 1905 ) 
Eckman, 1932** 

Synonyms: Gasterostomum baculum Lin- 
ton, 1905; Gasterostomum sp. Linton, 1900; 
Nannoenterum baculum (Linton, 1905 ) 

Host: Scomberomorus maculatus 

Site: intestine 

Locality: Dog Island Reef 


Rhipidocotyle transversale Chandler, 1935 

Synonym:  Prosorhynchus  grascilescens 
(Rud.) of Linton, 1940 

Hosts: Strongylura marina; *S. notata 

Site: intestine 

Locality: Alligator Harbor 


Prosorhynchus atlanticum Manter, 1940* * 

Synonym:  Gasterostomum sp. Linton, 
1910 

Host: Mycteroperca bonaci 

Site: intestine 

Locality: Alligator Harbor 

A single specimen was found; eggs meas- 
ured 32-35 by 21-23 microns. 


FAMILY FELLODISTOMATIDAE Nicoll, 
1913 


Tergestia pectinata (Linton, 1905 ) 
Manter, 1940 

Synonyms: Distomum pectinatum Linton, 
1905; Theledra pectinata (Linton) Linton, 
1910 

Hosts: Bairdiella chrysura; Caranx crysos; 
C. hippos 

Site: intestine 

Localities: Alligator Harbor; Dog Island 
Reef 


Steringotrema corpulentum (Linton, 1905 ) 
Manter, 1931 
Synonym: Distomum corpulentum Lin- 
ton, 1905 
Host: Lagodon rhomboides 
Site: intestine 


Locality: Alligator Harbor 


Trematodes of Marine Fishes 41 


FAMILY HAPLOSPLANCHNIDAE 
Poche, 1925 


Schikhobalotrema acutum (Linton, 1910) 
Skrjabin and Guschanskaja, 1955** 

Synonyms: Deradena acuta Linton, 1910; 
Haplosplanchnus acutus (Linton) Manter, 
1937 

Host: Strongylura marina 

Site; intestine 

Locality: Alligator Harbor 

Deposited specimen: U.S.N.M. No. 60081 


Schikhobalotrema sp. 
Host: Mugil cephalus 
Site: intestine 
Locality: Alligator Harbor 


The four specimens found are not favor- 
able for study. They probably represent a 
new species of haplosplanchnid. 


FAMILY GORGODERIDAE Looss, 1901 


Nagmia floridensts Markell, 1953 
Host; Dasyatis sabina 
Site: body cavity 
Locality: Alligator Harbor 


A great deal of confusion exists regarding 
generic features in the Anaporrhutinae, and 
the validity of the genus Nagmia has been 
questioned by Johnston (1934) and others. 
Nagmia floridensis was described from a 
single specimen, and the vitellaria were re- 
ported as partly medial and partly ventral to 
the ceca. Our material shows variation in 
their position, with the majority of the 
worms having vitellaria partly extracecal and 
partly overlapping the ceca ventrally. Two 
immature specimens show clearly the ex- 
cretory vesicle as Y-shaped; in adults, the 
unbranched stem is seen but its arms are 
concealed. 


FAMILY OPECOELIDAE Ozaki, 1925 


Opecoeloides fimbriatus (Linton, 1934) 
Sogandares-Bernal and Hutton, 1959 

Synonym: Cymbephallus fimbriatus Lin- 
ton, 1934 

Hosts: Bairdiella chrysura; Menticirrhus 
americanus; *M. focaliger; M. littoralis; Mr- 
cropogon undulatus; Sciaenops ocellata 

Site: intestine 

Localities: Alligator Harbor; Mud Cove; 
St. George Island 

The original description by Linton is in- 
adequate and the species has been redescribed 


42 Tulane Studies n Zoology 


by Sogandares-Bernal and Hutton (1959b), 
and by Kruse (1959) from Linton’s type 
specimen and additional ones collected from 
Apalachee Bay. The single specimen from 
Micropogon undulatus has a smaller sucker 
ratio (1:1.17) and fewer acetabular papillae 
(exact number cannot be determined). On 
the basis of these features, it should perhaps 
be referred to O. polynemt Von Wicklen, 
1946. Sogandares-Bernal and Hutton 
(1959c) questioned the validity of O. poly- 
nem1,; in sucker ratio (1:1.25) it comes close 
to the lower limit found in some of our 
specimens from the other hosts (range 1: 1.3- 
1.8). The papillae on the acetabulum may 
be retracted and thus may be indiscernible; 
Kruse (1959) reported “four lobes each hav- 
ing from five to nine papillae” and Sogan- 
dares-Bernal and Hutton (1959b, Fig. 13) 
show 6, 6, 6, and 8 papillae per lobe. No 
such variation, however, is reported by Von 
Wicklen in her 10 specimens of O. polynemz. 


Genitocotyle cablei n.sp. 
Figure 1 


Host: Ancylopsetta quadrocellata 
Site: intestine 

Locality: Dog Island Reef 
Holotype: U.S.N.M. No. 60082 


Description and measurements based on 
two specimens. Body elongated, 2.70-2.93 
long, 0.567-0.600 wide. Oral sucker 0.165- 
0.185 in diameter; ventral sucker in anterior 
third of body, pedunculate, 0.268-0.294 in 
diameter, with three or four small papillae 
on anterior and posterior margins; sucker 
ratio 1:1.54-1.62. Accessory “sucker” pit- 
like and without a limiting membrane, sur- 
rounded by a few cells, about half-way 
between pharynx and ventral sucker. Pre- 
pharynx short; pharynx large, 0.155 in di- 
ameter; esophagus slender, 0.294-0.360 long; 
cecal bifurcation at level of anterior margin 
of ventral sucker; ceca ending blindly near 
posterior end of body. Testes two, smooth, 
tandem, close together, 0.232-0.309 in di- 
ameter. Cirrus sac absent; seminal vesicle 
tubular, reaching posteriorly halfway be- 
tween ventral sucker and ovary; ejaculatory 
duct very long and slender, extending from 
posterior end of acetabulum to level of pos- 
terior margin of pharynx. Ovary entire, 
pretesticular, 0.155-0.180 in diameter; semi- 
nal receptacle absent; uterus preovarian; 
eggs 56-64 by 31-36 microns. Genital pore 


Vol? 


ventral, slightly sinistral, near level of pos- 
terior margin of pharynx. Vitelline follicles 
extending from level of posterior margin of 
ventral sucker to posterior end of body, con- 
fluent in posttesticular space. Excretory vesi- 
cle tubular, extending to ovary. 


This species is referred to the genus 
Genittocotyle Park, 1937, on the basis of an 
accessory sucker (preacetabular pit) and 
blind ceca, conditions determined on live 
material as well as on frontal sections of one 
of the two specimens. Unlike other mem- 
bers in the genus, this species has acetabular 
papillae. We do not feel, however, that a 
new genus is justified on that basis. 


Genitocotyle cablei differs from the other 
three species in the genus in having acetabu- 
lar papillae. It further differs from G. acirra 
Park, 1937, in the position of the genital 
pore, in lacking a limiting membrane around 
the accessory sucker, and in having smaller 
eggs; from G. atlantica Manter, 1947, chiefly 
in extent of vitellaria and shape of the 
gonads; and from G. heterosticht Mont- 
gomery, 1957, in extent of vitellaria, posi- 
tion of the genital pore and seminal vesicle, 
and in lacking a limiting membrane around 
the accessory sucker. Neither the whole 
mount nor the frontal sections in our lim- 
ited material show a true seminal receptacle. 
Such a structure is also reported as absent 
in G. heterosticht but present in the other 
two species. This structure is of generic 
value, at least in some opecoelids. 


The species is named in honor of Pro- 
fessor R. M. Cable of Purdue University, 
Lafayette, Indiana, in recognition of his con- 
tributions to the knowledge of the Trematoda. 


FAMILY LEPOCREADIIDAE Nicoll, 
1934 


Lepocreadinm brevoortiae n.sp. 
Figure 2 
Host: Brevoortia patronus 
Site: intestine 
Localities: Alligator Harbor; Mud Cove 
Holotype: U.S.N.M. No. 60083 


Description and measurements based on 
20 specimens. Body elongated, tapering an- 
teriorly, rounded posteriorly, 0.850-1.140 
long, 0.260-0.390 wide. Cuticle spinose; eye 
spot pigments diffuse. Oral sucker sub- 
terminal, 0.078-0.108 in diameter; ventral 
sucker in mid-third of body, sometimes equa- 


No. 2 


torial, 0.072-0.090 in diameter; sucker ratio 
1:0.85-1.00. Prepharynx absent or very 
short; pharynx massive, sometimes larger 
than oral sucker, 0.080-0.096 in diameter; 
esophagus about half to one and a half length 
of pharynx; cecal bifurcation about midway 
between suckers; ceca extending to level of 
posterior vitelline follicles. Testes two, 
tire, tandem, contiguous, 0.072-0.150 in di- 
ameter. Cirrus sac long, about 1/4 body 
length, sometimes reaching ovarian zone, 
containing subspherical internal seminal 
vesicle, large pars prostatica, and long mus- 
cular spiny cirrus; spines of cirrus minute, 
sometimes partially lost; external seminal 
vesicle saccate, often overlapping ovary dor- 
sally. Ovary triangular in shape, contiguous 
with anterior testis, 0.060-0.096 in diameter; 
seminal receptacle postovarian; uterus pre- 
ovarian. Eggs 60-66 by 31-41 microns. Vi- 
telline follicles extending from level of in- 
testinal bifurcation to near posterior end 
of body, confluent in posttesticular space. 
Genital atrium small; genital pore preace- 
tabular, sinistral. Excretory vesicle tubular, 
anterior extent not determined; excretory 
pore terminal. 


en- 


The combination of a massive pharynx 
any spiny cirrus distinguish Lepocreadiam 
brevoortiae from all the other 21 species 
in the genus. The massive pharynx is a con- 
stant feature not due to excessive flattening 
and was seen in the live material obtained 
from 13 fish from two localities. A large 
pharynx is described for L. znciswm Hanson, 
1955 and L. clavatum (Ozaki, 1932); Yama- 
guti, 1938 but both species lack a spiny 
cirrus, the cirrus sac does not extend pos- 
terior to the ventral sucker, and the ovary 
and testes are lobed. L. pyriforme (Linton, 
1900) Linton, 1940 has a spiny cirrus. 
Sogandares-Bernal & Hutton (1960) dis- 
cussed this species and concluded that there 
are several species involved in Linton’s de- 
scriptions. Nahhas & Cable (1964) ac- 
cepted as this species only individuals that 
are similar to Figure 47 (Linton, 1940) or 
Figure 9 (Sogandares-Bernal & Hutton, 
1960). On this basis, L. brevoortiae would 
differ from L. pyriforme by having a larger 
pharynx, shorter prepharynx, and more an- 
terior extent of the vitellaria. 


Trematodes of Marine Fishes 43 


Lepocreadium floridanus Sogandares-Bernal 
and Hutton, 1959 


Lagodon rhomboides 
intestine 
Alligator Harbor 

Three specimens are in close agreement 
with the description of Sogandares-Bernal 
and Hutton (1959a) except for a somewhat 
oval body shape rather than an elongated 
one. In one specimen, the testes were 
slightly oblique. Egg size was not given in 
the original description of the species. In 
our material the range is 54-72 by 26-38 
microns. 

Another group of more elongated worms 
with vitellaria extending only to the acetabu- 
lum, was found in the same host species. 
They were first thought to be Lepocreadium 
pyriforme (Linton, 1900) as limited in the 
discussion of the previous species. However, 
the cirrus lacks spines and for the time being 
the trematodes are considered as younger 
forms of Lepocreadium floridanus, 


Host: 
Site: 
Locality: 


Opechona gracilis (Linton, 1910 ) 
Manter, 1947** 
Figure 3 
Synonym: Prodistomum gracile Linton, 
1910; nec Opechona gracilis (Manter, 1931) 
Ward & Fillingham, 1934 
Host: *Peprilus alepidotus 
Site; intestine 
Locality: Mud Cove 


Deposited specimen: U.S.N.M. No. 60084 

The present material is referred to this 
species on the basis of shape of the ovary, 
extent of vitellaria and excretory vesicle, 
sucker ratio and other measurements. Our 
specimens differ, however, in egg size and 
in having a definite prepharynx varying in 
length from about one half to one and 
half the length of the pharynx. The eggs in 
our material are collapsed and measure 72- 
82 by 30-37 as compared with 61-64 by 
37-47 microns (Manter, 1947). 


Apocreadium mexicanum Manter, 1937** 


Host: Monacanthus hispidus 

Site: intestine 

Locality: Alligator Harbor 

This species was first described by Manter 
from the Pacific Coast. Siddiqi and Cable 
(1960) reported it from Puerto Rico but 
noted “slight differences in sucker ratio, 
width of eggs, and length of posttesticular 


44 


space.” Nahhas and Cable (1964) found 
this species in Monacanthus hispidus in Ja- 
maica and noted that their specimens were 
“more like those of Siddigi and Cable 
(1960 ) ’ and that “the posttesticular 
space usually is less than half as long as the 
body but sometimes the two regions are 
about equal in length.” Eggs of the Florida 
material measure 70-84 by 30-48 microns 
compared with 63-71 by 42-45 microns for 
the Jamaican material. Manter (1937) gave 
an egg size range of 61-67 by 31-34 microns. 


Homalometron pallidum Stafford, 1904 
Host: Letostomus xanthurus 

Site: intestine 

Locality: Alligator Harbor 


Multitestis inconstans (Linton, 1905 ) 
Manter, 1931** 
Synonym: Distoma inconstans Linton, 
1905 
Host: Chaetodipterus faber 
Site: intestine 
Locality: Alligator Harbor 


Deposited specimen: U.S.N.M. No. 60085 


Diploproctodaeum plicitum (Linton, 1928 ) 
Sogandares-Bernal & Hutton, 1958 

Synonyms: Distomum sp. of Linton, 1898 
and 1905; Psilostomum plicitum Linton, 
1928; Biantum concavum Stunkard, 1930; 
B. adplicatum Manter, 1940; B, plicitum 
(Linton) Stunkard, 1931 

Host: Chilomycterus schoepfi 

Site: intestine 

Locality: Alligator Harbor 


Dermadena lactophryst Manter, 1946** 

Synonym: Distomum lamelliforme Lin- 
ton, 1907 in part 

Host: Lactophrys quadricornis 

Site: intestine 

Locality: Alligator Harbor 

Deposited specimen: U.S.N.M. No. 60086 


FAMILY CRYPTOGONIMIDAE Ciurea, 
bys) 
Siphodera vinaledwardsu (Linton, 1899 ) 
Linton, 1910 


Synonym: Monostomum vinaledwardsu 
Linton, 1899 

Host: Opsanus beta 

Site: intestine 

Locality: Alligator Harbor 


Tulane Studies in Zoology 


Metadena adglobosa Manter, 1947** 
Host: *Paralichthys albigutta 
Site: ceca 
Locality: Alligator Harbor 


Two specimens, one mature but damaged, 
and one immature, were recovered along 
with a number of individuals of Bucepha- 
loides bennetti. The egg size and that of the 
oral sucker relative to body width are char- 
acteristic of this species. This species has 
hitherto been known only from snappers of 
the genus Lutjanus. 


Pseudoacanthostomum floridensis n.sp. 
Figure 4 


Synonym:  Pseudoacanthostomum  pana- 
mensis of Corkum, 1959, nec Caballero et 
al., 1953 

Host: Galetchthys felis 

Site: intestine 

Locality: Alligator Harbor 

Holotype: US.N.M. No. 60087 


Description and measurements based on 
two specimens, one sectioned  frontally. 
Body elongated, 2.63-3.00 long, 0.489-0.750 
wide. Cuticle with spines extending to level 
of posterior testis; eye spot pigments pres- 
ent. Oral sucker like an inverted bell, 0.180- 
0.294 long, 0.309-0.330 in greatest width; 
mouth surrounded by single row of 28 pe- 
rioral spines measuring 42-60 by 18-24 
microns; ventral sucker in anterior third of 
body, 0.118-0.155 long, 0.155-0.170 wide; 
sucker ratio 1:0.54. Prepharynx contracted 
in holotype, longer than pharynx in para- 
type; pharynx 0.129-0.206 in diameter; 
esophagus very short; ceca extending to pos- 
terior end of body, and joining excretory 
vesicle by two narrow ducts a short distance 
anterior to excretory pore. Testes two, ovoid 
or rhomboid, tandem, well separated, 0.283- 
0.309 long, 0.180-0.283 wide; seminal vesi- 
cle tubular, sinuous, extending posteriorly to 
about halfway between ventral sucker and 
ovary; prostate cells free in parenchyma. 
Ovary trilobed, about midway between ven- 
tral sucker and anterior testis, 0.232-0.260 
long, 0.298-0.309 wide; seminal receptacle 
spherical, preovarian; uterine coils extending 
to near posterior tips of ceca. Genital pore 
median, immediately preacetabular; gonotyl 
as large as ventral sucker, the two sometimes 


overlapping. Eggs 20-25 by 11-14 microns. | 


Vitelline follicles small, sometimes granular, 
extending from anterior testis laterally and 


I 


No. 2 


dorsally some distance anterior to ventral 
sucker but not reaching intestinal bifurca- 
tion. Excretory vesicle Y-shaped, wide arms 
extending from near posterior testis to mid- 
level of pharynx; pore terminal. 

This is the second species in the genus 
Pseudoacanthostomum. P. floridensis dif- 
fers from P. panamensts Caballero, Bravo H. 
and Grocott, 1953 from Galeichthys seemant 
from the Pacific Coast in the number of 
perioral spines (28 compared with 26), 
greater extent of the vitellaria, and the pres- 
ence of a uroproct. This last feature was 
suspected in the live material and confirmed 
by frontal sectioning of the paratype. 

Corkum (1959) reported a single speci- 
men with 28 perioral spines as P. panamensts 
from Galeichthys felis. We have borrowed 
this specimen and found it to agree with our 
material also in the distribution of the vi- 
tellaria. The connections of the ceca with 
the stem of the vesicle could not be deter- 
mined as they were concealed by the uterine 
coils. Figure 5 is a tracing of a photomicro- 
graph of Corkum’s material. 


FAMILY ACANTHOCOLPIDAE Luhe, 
1909 
Stephanostomum ditrematis (Yamaguti, 
1939) Manter, 1947 

Synonyms: Echinostephanus  ditrematts 
Yamaguti, 1939; Stephanostomum longiso- 
mum Manter, 1940; Stephanostomum filt- 
forme Linton, 1940 

Host: Caranx hippos 

Site: intestine 

Locality: Alligator Harbor 


Stephanostomum interruptum Sparks & 
Thatcher, 1958 
Hosts: Batrdiella chrysura; Cynoscion are- 
narius; C. nebulosus 
Site: intestine 
Locality: Alligator Harbor 


Stephanostomum megacephalum Manter, 
1940 

Host: Caranx hippos 

Site: intestine 

Locality: Alligator Harbor 


Stephanostomum sentum (Linton, 1910) 
Manter, 1947** 
Synonym: Stephanochasmus sentus Lin- 
ton, 1910 
Host: *Menticirrus americanus 
Site: intestine 
Locality: Alligator Harbor 


Trematodes of Marine Fishes 45 


Stephanostomum metacercaria 

Host: Monacanthus hispidus 

Site: wall of the heart 

Locality: Alligator Harbor 

A single specimen, with 34 perioral spines 
and an oral sucker smaller than the ventral 
sucker, was found encysted on the wall of 
the heart. 


Pleorchis americanus Lihe, 1906 

Synonyms: Distomum polyorchis Linton, 
1901 nec Stossich, 1888; Distoma molle 
(Leidy, 1856) Stiles & Hassall, 1894; 
Pleorchis mollis (Leidy, 1856) Stiles, 1896; 
Pleorchis lintoni Yamaguti, 1938; Polyorchis 
molle (Leidy, 1856) Mont., 1896 

Hosts: Cynoscion arenarius; C. nebulosus 

Site: intestine 

Localities: Alligator Harbor; Dog Island 
Reef; St. Marks 


FAMILY HEMIURIDAE Luhe, 1901 


Aponurus laguncula Looss, 1907 
Hosts: *Centropristis melanus; *Lago- 
cephalus laevigatus; *Paralichthys albigutta 
Site: stomach 
Localities: Alligator Harbor; Dog Island 
Reef; St. George Island 


Fourteen worms collected from three fishes 
are 0.541-1.275 long, 0.138-0.335 wide. We 
first thought that three worms from Lago- 
cephalus laevigatus represented a different 
species because they were larger (1.200- 
1.275 by 0.319-0.335) than those from the 
other two hosts (0.541-0.849 by 0.138- 
0.180) and their eggs were slightly thicker- 
shelled, narrower at one end, and measure 
30-32 by 17-18 compared with 26-31 by 
14-17 microns. Egg measurements overlap, 
and proportions of organs are the same, how- 
ever. In body size and egg shape, the three 
larger trematodes are similar to A. trachinott 
Manter, 1940 but this species has smaller 
eggs (25 by 10 microns). 


Aponurus elongatus Siddiqi & Cable, 
1960** 

Host: Chaetodipterus faber 

Site: stomach 

Localities: Alligator Harbor; Dog Island 
Reef 

Deposited specimen: U.S.N.M. No. 60088 

Three specimens found in this study agree 
closely with the description of Siddiqi & 
Cable (1960) but differ in having slightly 


46 Tulane Studies in Zoology 


larger eggs (28-35 by 16-18 compared with 
26-29 by 13-16 microns). Siddigi and Cable 
did not distinguish their species from others 
in the genus. It is most similar to A. lagun- 
cula but differs in sucker ratio (1:2.5 com- 
pared to 1:1.7-2.1) and in having a more 
elongate body, more anterior ventral sucker, 
a greater postovarian space, and vitellaria 
that are longer than wide. A. elongatus is 
known only from Chaetodipterus faber and 
has been reported from Puerto Rico, Jamaica, 
and now from Apalachee Bay. 


Lecithaster confusus Odhner, 1905 ** 
Synonym: Distomum bothryophoron Ols- 
son of Linton, 1899 
Hosts: *Brevoortia patronus; *Lagodon 
rhomboides 
Site: intestine 
Locality: Alligator Harbor 


Parahemiurus merus (Linton, 1910) 
Woolcock, 1935 

Synonyms: Hemiurus merus Linton, 1910; 
Parahemiurus parahemiurus Vas & Pereira, 
1930; P. platichthyi Lloyd, 1938; P. atherinae 
Yamaguti, 1938; P. harengulae Yamaguti, 
1938 

Hosts: Brevoortia patronus; Cynoscion 
nebulosus; *Lagodon rhombotdes 

Site: stomach 

Locality: Alligator Harbor 


Sterrhurus monticelli (Linton, 1898 ) 
Linton, 1910 
Synonym: Distomum monticelli Linton, 
1898 
Host: Pomatomus saltatrix 
Site: stomach 


Locality: Dog Island Reef 


Sterrhurus musculus Looss, 1907 

Synonyms: Sterrhurus laeve (Linton) of 
Manter, 1931; Sterrhurus floridensis Manter 
1934 in part 

Hosts: * Ancylopsetta quadrocellata; * An- 
guilla rostrata; *Batrdiella chrysura; *Cen- 
tropristis melanus; *Diplectrum formosum; 
*Letostomus xanthurus; Menticirrhus amert- 
canus; *Mtcropogon undulatus; *Ogco- 
cephalus radiatus; *Ophidion welsht; *Op- 
sanus beta; *Orthopristis chrysopterus; 
*Paralichthys albigutta; *Syacium  papil- 
losum; Synodus foetens; *Urophycts flort- 
danus 

Site: stomach 

Localities: Alligator Harbor; Dog Island 
Reef; St. George Island 


by 


Vola 


Lecithochirium parvum Manter, 1947 

Synonym: Sterrhurus floridanus Manter 
1934 in part 

Hosts: *Letostomus xanthurus; * Micro- 
pogon undulatus; *Paralichthys albigutta 

Site: stomach 

Locality: Alligator Harbor 


> 


Lechithochirium microstomum Chandler, 
1935 

Synonym: — Lecithochirinm 
Bravo-Hollis, 1956 

Hosts: *Angualla rostrata; Trichiurus lep- 
turus 

Site: stomach 

Localities: Alligator Harbor; Mud Cove 


sinaloense 


Lecithochirium texanum (Chandler, 1941) 
Manter, 1947 


Synonym: Sterrhurus texanus Chandler, 
1941 

Host: *Selene vomer 

Site: stomach 


Locality: Alligator Harbor 


Lecithochirium mecosaccum Manter, 
1 947 * * 
Figure 6 


Hosts: *Sciaenops ocellata; Synodus foe- 
tens 

Site: stomach 

Locality: Alligator Harbor 

The main distinguishing features of 
Lecithochirtum mecosaccum ate the broad 
vitelline lobes, the large sinus sac and ejacu- 
latory vesicle, and a long muscular herma- 
phroditic duct. The preacetabular pit, de- 
scribed as indistinct and nonglandular, was 
not observed in specimens from Synodus 
foetens but was evident in some of the speci- 
mens from Sczaenops ocellata. The genital 
pore is a slit-like opening usually just pos- 
terior to the pharynx but may be more pos- 
terior due to contraction of the muscular 
hermaphroditic duct. 


Lecithocladium excisum (Rudolphi, 1819) 
Luhe, 1901** 
Synonyms:  Lecithocladium  excisiforme 
Cohn, 1903; L. gulosum (Linton, 1899) 
Looss, 1907; L. cristatum (Rudolphi, 1819) 


Looss, 1907; L. crenatum (Molin, 1859) 
Looss, 1907 

Hosts: *Peprilus aleptdotus; Poronotus 
triacanthus 


Site: stomach 


| 


No. 2 Trematodes of Marine Fishes 47 


Figure 1. Genitocotyle cablei, holotype, ventral view. Figure 2. Lepocreadium brevoor- 
tiae, holotype, ventral view. Figure 3. Opechona gracilis, ventral view. Figure 4. Pseu- 
doacanthostomum floridensis, holotype, ventral view. Figure 5. Same, tracing of a pho- 
tograph of Corkum’s specimen showing mainly forebody. Figure 6. Lecithochirium meco- 
saccum, ventral view, from Synodus foetens. 


48 Tulane Studies in Zoology 


Localities: Alligator Harbor; St. George 
Island 
Deposited specimen: U.S.N.M. No. 60089 


Stomachicola sp. 

Host: Diplectrum formosum 

Site: attached to ovary 

Locality: St. George Island 
Tubulovesicula sp. 

Hosts: Cynoscion arenarius; C. nebulosus 

Site: beneath ovarian membrane and in 

body wall muscles 
Locality: Alligator Harbor 


The worms were found on several occa- 
sions by the second author. Some contained 
eggs although the majority were immature. 
No description of the species will be given 
at the present since the majority of the 
worms are not in condition favorable for 
description. 


FAMILY SCLERODISTOMIDAE Dollfus, 
1932 


Sclerodistomum sphoerotdis Manter, 1947 
Host: Chilomycterus schoepfi 

Site: stomach 

Locality: Alligator Harbor 


V. SUMMARY 


Forty-eight species of Digenea are re- 
ported from 43 species of fishes from Apa- 
lachee Bay, Florida. Three new species are 
described: Gemnitocotyle cablei, (Opecoe- 
lidae); Lepocreadium brevoortiae, (Lepo- 
creadiidae ) and  Pseudoacanthostomum 
floridensis, (Cryptogonimidae). Fourteen 
new locality records bring to 109 the spe- 
cies of Digenea known from Tampa Bay 
and the northern Gulf: 27 species from the 
Texas coast, 50 from Louisiana, 16 from 
Mississippi, 31 from Tampa and Boca Ciega 
Bays, and 48 from Apalachee Bay.. 


VI. ALPHABETICAL Host-PARASITE LIST 


Following each host species is the number, 
in parentheses, of individuals examined. 


Ancylopsetta quadrocellate Gill ocellated flounder (1) 
Genitocotyle cablei 
Sterrhurus musculus 

Anguilla rostrata (LeSueur), American eel (2) 
Lecithochirium microstomum 
Sterrhurus musculus 

Bairdiella chrysura (Lacépéde), silver perch (18) 
Bucephaloides caecorum 
Tergestia pectinata 
Opecoeloides fimbriatus 


Vol. 12 


Stephanostomum interruptum 
Sterrhurus musculus 
Brevoortia patronus Goode, largescale menhaden (24) 
Lepocreadium brevoortiae 
Lecithaster confusus 
Parahemiurus merus 
Caranx crysos (Mitchill), blue runner (5) 
Bucephalus varicus 
Tergestia pectinata 
Ceranx hippos (Linnaeus), Crevalle jack (3) 
Bucephalus varicus 
Tergestia pectinata 
Stephanostomum ditrematis 
Stephanostomum megacephalum 
Centropristis melanus Ginsburg, Southern sea bass (10) 
Aponurus laguncula 
Sterrhurus musculus 
Chaetodipterus faber (Broussonet), Atlantic 
spadefish (9) 
Multitestis inconstans 
Aponurus elongatus 
Chilomycterus schoepfi (Walbaum), striped 
burrfish (3) 
Diploproctodaeum plicitum 
Sclerodistomum sphoeroidis 
Cynoscion arenarius Ginsburg, sand sea trout (5) 
Cardicola laruei 
Pleorchis americanus 
Stephsnostomum interruptum 
Tubulovesicula sp. 
Cynoscion nebulosus (Cuvier), spotted sea 
trout (21) 
Cardicola laruei 
Preorchis americanus 
Stephanostomum interruptum 
Paraheminurus merus 
Tubulovesicula sp. 
Dasyatis sabina (LeSueur), Atlantic stingray (1) 
Nagmia floridensis 
Diplectrum formosum (Linnaeus), sand perch (3) 
Sterrhurus musculus 
Stomachicola sp. 
Galeichthys felis (Linnaeus), sea catfish (16) 
Pseudoacanthostomum floridensis 
Lactophrys quadricornis (Linnaeus), cowfish (2) 
Dermadena lactophrysi 
Lagocephalus laevigatus (Linnaeus), smooth 
puffer (1) 
Aponurus laguncula 
Legodon rhomboides (Linnaeus), pinfish (29) 
Steringotrema corpulentum 
Lepocreadium floridanus 
Lecithaster confusus 
Parahemiurus merus 
Leiostomus xanthurus Lacépéde, spot (8) 
Homalometron pallidum 
Lecithochirium parvum 
Sterrhurus musculus 
Menticirrhbus americanus (Linnaeus), Southern 
kingfish (1) 
Opecoeloides fimbriatus 
Stephanostomum sentum 
Sterrhurus musculus 
Menticirrhus focaliger Ginsburg, minkfish (1) 
Opecoeloides fimbriatus 


Menticirrhus littoralis (Holbrook), Gulf kingfish (1) 
Opecoeloides fimbriatus 


No. 2 


Micropogon undulatus (Linnaeus), Atlantic 
croaker (12) 
Opecoeloides fimbriatus 
Lecithochirium parvum 
Sterrhurus musculus 
Monacanthus hispidus (Linnaeus), planehead 
filefish (9) 
Apocreadium mexicanum 
Stephanostomum metacercaria 
Mugil cephalus Linnaeus, striped mullet (4) 
Schikhobalotrema sp. 
Mycteroperca bonaci (Poey), black grouper (1) 
Prosorhynchus atlanticus 
Ogcocephalus radiatus (Mitchill), polka-dot 
batfish (2) 
Sterrhurus musculus 
Ophidion welshi (Nichols and Breder), crested 
cusk-eel (5) 
Sterrhurus musculus 
Opsanus beta (Goode and Bean), Gulf 
toadfish (8) 
Siphodera vinaled ward sii 
Sterrhurus musculus 
Orthopristis chrysopterus (Linnaeus), pigfish (12) 
Sterrhurus musculus 
Paralichthys albigutta Jordan and Gilbert, Gulf 
flounder (9) 
Bucephaloides bennetti 
Metadena ad globosa 
Aponurus laguncula 
Lecithochirium parvum 
Sterrhurus musculus 
Peprilus alepidotus (Linnaeus), Southern 
harvestfish (3) 
Opechone gracilis 
Lecithocladium excisum 
Pomatomus saltatrix (Linnaeus), bluefish (3) 
Bucephaloides arcuatus 
Sterrhurus monticelli 
Poronotus triacanthus (Peck), butterfish (1) 
Lecithocladium excisum 
Sciaenops ocellata (Linnaeus), red drum (2) 
Bucephaloides megacirrus 
Opecoeloides fimbriatus 
Lecithochirium mecosaccum 
Scoliodon terrae-novae (Richardson) Atlantic 
sharpnose shark (1) 
Selachohemecus olsoni 
Scomberomorus maculatus (Mitchill), Spanish 
mackerel (1) 
Bucephaloides arcuatus 
Rhipidocotyle baculum 
Selene vomer (Linnaeus), lookdown (1) 
Lecithochirium texanum 
Strongylura marina (Walbaum), Atlantic 
needlefish (3) 
Rhipidocotyle transversale 
Schikhobalotrema acutum 
Strongylura notata (Poey), redfin needlefish (2) 
Rhipidocotyle transversale 
Syscium papillosum (Linnaeus), dusky flounder (1) 
Sterrhurus musculus 
Synodus foetens (Linnaeus), inshore lizardfish (2) 
Lecithochirium mecosaccum 
Sterrhurus musculus 
Trichiurus lepturus Linnaeus, Atlantic cutlassfish (1) 
Lecithochirium microstomum 


Trematodes of Marine Fishes 49 


Urophycis floridanus (Bean and Dresel), Southern 
hake (2) 


Sterrhurus musculus 


VII. List OF FISHES NEGATIVE FOR 
TREMATODES 


The numbers in parentheses following 
common names of fishes represent numbers 


of individuals examined. 

Anchos hepsetus (Linnaeus), striped anchovy (2) 

Archosargus probatocephalus (Walbaum), 
sheepshead (1) 

Bagre marinus (Mitchill), gafftopsail catfish (1) 

Cyprinodon variegatus Lacépéde, sheepshead 
minnow (1) 

Dorosoma cepedianum (LeSueur), gizzard shad (2) 

Echeneis naucrates Linnaeus, sharksucker (1) 

Elops saurus Linnaeus, ladyfish (2) 

Etropus crossotus Jordan and Gilbert, fringed 
flounder (1) 

Eucinostomus argenteus Baird and Girard, spotfin 
mojarra (8) 

Eucinostomus gule (Quoy and Gaimard), silver 
jenny (1) 

Fundulus similis (Baird and Girard), longnose 
killifish (9) 

Haemulon sciurus (Shaw), blue striped grunt (1) 

Larimus fasciatus Holbrook, banded drum (1) 

Lutjanus griseus (Linnaeus), gray snapper (1) 

Menidia berylline (Cope), tidewater silverside (3) 

Mugil curema Valenciennes, white mullet (2) 

Paralichthys lethostigma Jordan and Gilbert, Southern 
flounder (1) 

Porichthys porosissimus (Cuvier), Atlantic 
midshipman (3) 

Prionotus tribulus Cuvier, bighead searobin (1) 

Trinectes maculatus (Bloch and Schneider), 
hogchoker (4) 


VIII. REFERENCES CITED 


CorkuM, K. C. 1959. Some trematode para- 
sites of fishes from the Mississippi Gulf 
coast. Proc. Louisiana Acad. Sci. 22: 17- 
29. 


JOHNSTON, T. H. 1934. Some Australian 
anaporrhutine trematodes. Trans. Roy. 
Soc. South Australia. 58: 139-148. 


KrusgE, D. N. 1959. Parasites of the com- 
mercial shrimps, Penaeus aztecus Ives, 
P. duorarum Burkenroad and P. setiferus 
(Linnaeus). Tulane Stud. Zool. 7: 123- 
144, 

LINTON, E. 1940. Trematodes from fishes 
mainly from the Woods Hole region, 
Massachusetts. Proc. U. S. Natl. Mus. 
88: 1-172. 

MANTER, H. W. 1937. A new genus of dis- 
tomes (Trematoda) with lymphatic ves- 
sels. Hancock Pac. Exp. 2: 11-22, pl. 


SEES ete ts Paes 1947. Digenetic trema- 
todes of marine fishes of Tortugas, Flori- 
da. Amer. Midland Nat. 38: 257-416. 


origin, waters, and marine life.’ Fishery 


50 Tulane Studies n Zoology 


Bull. (89) of the U. S. Fish and Wildlife 
Service. 55: 335-350. 

NAHHAS, F. M. and R. M. CABLE 1964. Di- 
genetic and aspidogastrid trematodes 


from marine fishes of Curacao and Ja- 
maica. Tulane Stud. Zool. 11: 169-228. 


RIGGIN, G. T., JR. and A. K. SPARKS 1962. 
A new gasterostome, Bucephaloides meg- 
accirrus, from the redfish, Sciaenops ocel- 
lata. Proc. Helminthol. Soe. Wash. 29: 
D=29) 

SHort, R. B. 19538. 
dicola laruei n.g., 
from marine fishes. 
309. 


A new blood fluke, Car- 
n.sp. (Aporocotylidae) 
J. Parasitol. 39: 304- 


: _.. 1954. A new blood fluke, 
Selachohemecus olsoni, n.g., n.sp. (Aporo- 
cotylidae) from the 'sharp- nosed shark, 
Scoliodon terrae-novae. Proce. Helminthol. 
Soc. Wash. 21: 78-82. 

Srppiqi, A. and R. M. CABLE 1960. Dige- 
netic trematodes of marine fishes of 
Puerto Rico. Sci. Sur. Porto Rico and 
the Virgin Is. 17: 257-369. 

SOGANDARES-BERNAL, F. and R. F. Hutron 
1959a. Studies on helminth parasites of 


Vol. 12 


the coast of Florida I. Digenetie trema- 
todes of marine fishes from Tampa and 
Boca Ciega Bays with descriptions of two 
new species. 1. Bull. Mar. Sci. Gulf 
Carib. 9: 53-68. 

jks Seer Mees aed ase, 1959b. Studies on hel- 
minth_ parasites from the coast of Flori- 
da. III. Digenetic trematodes of marine 
fishes from Tampa and Boca Ciega Bays. 
J. Parasitol. 45: 337-346. | 

: _..... 1959c. Studies on hel='3 
minth “parasites from the coast of Flori- 
da. IV. Digenetic trematodes of marine 
fishes of Tampa, Boca Ciega Bays, and 
the Gulf of Mexico. 8. Quart. J. Fla. 
Aicad. Sev. 2s 259-2138: 


s : 1960. The status of some 
marine species ‘of Lepocreadium Stossich, 
1904 (Trematoda: Lepocreadiidae) from 
the North American Atlantic. Lib. Hom. 
E. Caballero y C. (Mexico) : 275-283. 


SpaRKS, A. K. 1960. Some aspects of the 
zoogeography of the digenetic trematodes 
of shallow-water fishes of the Gulf of 
Mexico. Lib. Hom. E. Caballero y C. 
(Mexico) : 285-298. 


February 23, 1965 


TULANE STUDIES IN ZOOLOGY 


June 23, 1965 


Volume 12, Number 3 


HISTOLOGY, DEVELOPMENT, AND INDIVIDUAL VARIATION OF 
COMPLEX MUROID BACULA 


ANDREW A. ARATA, 
NORMAN C. NEGUS 


and 
MARTHA SAPP DOWNS,! 
Department of Zoology, 
Tulane University, 
New Orleans, Louisiana 


CONTENTS 
PAA ca aT GOS TNAGT GOP TSO SS te ah ger ee see eg eet nd Ow Le Wess ey Sy 
HeVEERERTALCCANTD METHODS 2..- <8 i I ee oe 52 
Ul. RIESTONETES JAIN MDY | DI CLUISSOVN ee PES) 
PMI S COLO De ae sree ee BO ee SERINE A 2) 
ib) Development and individual vatiation 55 
C. Os clitorides in muroid genera with complex bacula______-______---------------- 61 
1b) petleas Oni © alG tin pli CATIONS. x ae. ie ees oes ee St Bae 62 
VAG KINIONTGEDGHMEN TS <0 ee te ee ee 63 
WAM IMERERETTOES (GVLED = ec 200 ety ee ee 64 


ABSTRACT 


Bacular development, morphology, and 
variation was studied in Microtus, On- 
datra, Sigmodon, Mesocricetus, and 
Rattus. 

Bacular shaft development is essen- 
tially similar in all forms in which it 
was studied. A synovial joint is de- 
scribed as present between the shaft 
and the distal processes of the bacu- 
lum. The distal processes were ob- 
served cssified only in Rattus. In all 
other forms studied, the cartilage of 
these processes calcifies when sexual 
maturity is reached. 


1 Present address, Department of Zoolo- 


-gy, University of California, Berkeley. 


The tctal length of the baculum and 
the bacular irdex (a summation of the 
length times the width of the shaft 
and the preduct cf the length of the 
median precess times that of a lateral 
distal process) shows no correlation 
with known-age of 96 Microtus mon- 
tanus, but, rather, is related to the to- 
tal length of the individual. The devel- 
cpment and absolute form of the bacu- 
lum presumably is ccntrolled in part 
by hcrmonal and genetic factors, and 
chronological age is not as important 
as physiological age in its development. 

Individual variation in the baculum 
of Microtus montanus is described. The 
“og clitoridis” of Mesocricetus is not 
hemolegcus to that of Ondatra as each 


EDITORIAL COMMITTEE FOR THIS PAPER: 
W. RoBert EApIE, Professor of Zoology, Cornell University, Ithaca, New York 


EMME? T. Hooper, Professor of Zoology, Museum of Zoology, University of Michi- 
gan, Ann Arbor, Michigan 


W. B. Quay, Associate Professor of Zoology, University of California, Berkeley, Calt- 
fornia 


5) 


52 Tulane Studies in Zoology 


bone or cartilaginous element is appar- 
ently homologous to a different part of 
the complex baculum. 


The similarity observed in the devel- 
opment, histology, and general form of 
the baculum of Rattus and the cricetids 
studied herein, suggests that murids 
and cricetids represent but a _ single 
family. 


I. INTRODUCTION 
The baculum of many muroid rodents 
consists of a proximal shaft and three distal 
processes (Figure 1). It has been recognized 
for a long time (Gilbert, 1892; Tullberg, 
1899), and considered characteristic of the 


Imm 


Figure 1. Views of the complex baculum 
of Sigmodon hispidus. The parts of the 
baculum are: median (mp) and lateral 
(Ip) distal processes; the spine (sp) and 
base (b) of the shaft. The views illustrat- 
ed are: A. lateral, B. dorsal (anti-ure- 


thral), C. ventral, D. distal (urethral up- 
permost), E. proximal (anti-urethral up- 
permost). 


Microtinae, the Cricetini, and certain Neo- 
tropical or neotropically derived Hesperomy- 
ini (Cricetinae) and some Muridae (Hooper 
and Musser, 1964). 


Hamilton (1946) described the baculum 
in numerous Microtinae, as well as in Szg- 
modon and Oryzomys (Cricetinae), and 
pointed out the similarity of the structure in 
such supposedly diverse groups. He also il- 
lustrated a series of bacula of Microtus penn- 
sylvanicus and showed the general change in 
form associated with the assumed age of the 


Volsa2 


animal. Callery (1951) illustrated series of 
bacula from a few known-age hamsters 
(Mesocricetus auratus) produced by inbreed- 
ing from a single pair of animals. Anderson 
(1960) figured a growth curve in which 
length of the bacular shaft of Mzcrotus och- 
rogaster was plotted against total length of 
the animal. Elder and Shanks (1962) dis- 
cussed bacular changes in a limited series of 
known-age muskrats (Ondatra zibethicus). 
To our knowledge, no study is available de- 
scribing changes in the morphology of the 
baculum in a large series of known-age ant- 
mals, or considering the histology and 
changes occurring in the distal processes of 
this element. 


Il. MATERIALS AND METHODS 


This report is based on histological obser- 
vations of the bacula of 6 muroid genera 
(Table 1), and approximately 50 locally 
collected hystricomorphs (Myocastor coy- 
pus). One-hundred and thirty-eight Mzcro- 
tus montanus (including 97 known-age 
males and 21 known-age females) used in 
this study for growth and development data 
were taken from a laboratory breeding col- 
ony maintained by one of us (Negus). This 
colony originated from about 100 Mzcrotus 
montanus live trapped in Jackson Hole, 
Wyoming. These animals were maintained 


TABLE 1. 

Muroid species and number of specimens 
(in parentheses) examined in this study. 
Supergeneric groupings follow 
Simpson (1945). 


Superfamily Muroidea 
Family Cricetidae 
Subfamily Cricetinae 

Tribe Cricetini 

Mesocricetus auratus 
(males 33) females*2) === 5 

Tribe Hesperomyini 

Sigmodon hispidus 


(males 38; females 1)... 4 
Peromyscus gossypinus 
(males 4; females 2). 6 


Subfamily Microtinae 
Tribe Microtini 
Ondatra zibethicus 
(males 5;- females 93) == 8 
Microtius montanus 
(males 148; females 33)... 176 
Family Muridae 
Subfamily Murinae 
Rattus norvegicus 
(males >> females 2) === 7 


Total Specimens Examined 206 


No. 3 


as pairs in the laboratory, and fed a basic 
diet of rabbit chow supplemented every few 
days with lettuce and other greens. A con- 
stant photoperiod of 18 hours per day was 
maintained and room temperature was main- 
tained by air conditioning. No inbreeding 
was permitted in the colony. Individuals 
were weaned at 15 days of age, at which 
time the litters were placed in separate 
cages, weighed, measured and sexed. 


Ill. RESULTS AND DISCUSSION 
A. Histology 


The bacular shaft of all forms we have 
examined is true bone. It consists of a lat- 
erally enlarged basal area to which the M. 
corpus cavernosus attaches and a spine-like 
distal projection (Figure 1). In all respects, 
the structure in cricetids is similar to that 
of Rattus (Ruth, 1934). In small species 
(i.e. Microtus montanus) and small individ- 
uals of large forms (2ze., Sigmodon) the 
shaft is formed by a single haversian system 
identical to that of the simple baculum of 
Peromyscus and other Nearctic cricetines 
(Figure 2). The spine may be composed of 
several haversian systems in larger forms 
(e.g. In cross-section the spine 


GK, 73 


on 


of the phallus of 
Peromyscus gossypinus, illustrating the na- 
ture of the spine of the baculum (bac). 


Figure 2. Cross-section 


is circular, oval, or dorso-ventrally flattened. 
This spine is generally characteristic of the 
species, but much variation and overlap 
exists. 

Ruth (1934) termed the bony develop- 
ment of the shaft of Rattws an endoblastemal 
ossification in which osteogenic cells become 
active in laying down osteoid substance be- 


Muroid Bacula 5) ) 


fore any marked differentiation of surround- 
ing tissues can be observed. Although we 
have not sectioned pre- or neo-natal crice- 
tids, the bony formation in one-week-old 
Microtus is similar to that described by Ruth 
(op. cit.). Diameter increase is by means 
of an active periosteum. An endosteum is 
seen in young animals. Maximum shaft 
length is achieved near breeding age. 

Hemopoietic bone marrow and fatty tissue 
are present in the enlarged basal area of the 
shaft (Figure 3). Cancellous bone is present 
in some species. In large individuals of 
Microtus, and in most individuals of larger 
forms (e.g. Ondatra) these tissues extend 
into the medullary cavity of the spine for 
more than one-half its length. 

The several elements of the complex bacu- 
lum (the shaft and the distal processes) are 
not of the same origin or histological nature. 
The distal processes, often referred to as 
cartilage, ossifying in adults, have not been 
described histologically. The cartilaginous 
nature of these processes in young individ- 
uals has been described by many (Hamilton, 
1946; Callery, 1951; Dearden, 1958; Ander- 
son, 1960; Elder and Shanks, 1962; and 
others ), but the subsequent “bony” develop- 
ment often described is usually considered to 
be typical endochondral ossification. In only 
one form (Rattus) have we observed this to 
be the case. 

The “ossifications” of the distal processes 
of the complex cricetid baculum seen are 
only calcifications of either hyaline or fibro- 
cartilage. In Mesocricetus (Figure 4), Mi- 
crotus (Figure 5) and Szgmodon, no true 
ossifications were found. Only in Rattus 
(Figure 6) were true ossifications of the 
distal processes observed. An apparent rea- 
son for this oversight in previous work is 
that most studies on bacular morphology 
employ clearing (in KOH and _ glycerin) 
and staining (with Alizarin Red) of the 
whole glans penis in which the bony struc- 
ture is found. Staining by Alizarin Red is 
not specific to bone, however, but calcium 
specific, and differentiation between an ossi- 
fication and a calcification is not discernible 
with this technique. 

The baculum of Rattus is usually con- 
sidered to consist of but two osseous portions 
(Taylor, 1961) and although Hooper (1960) 
and Hooper and Musser (1964) do consider 
the glans penis of murines to represent the 
complex type, the presence of the lateral 


54 Tulane Studies in Zoology 


wba Sale 


aah oil 


Figures 3-6. Histological preparations of phalli. 3. Longitudinal section through the phal- 
lus of Microtus montanus showing hemopoietic tissue present in the enlarged basal area 


of the baculum. 


4-6. Cross-sections through the distal regions of the phalli showing the 


relative sizes and nature of the distal processes. 4. Mesocricetus auratus 5. Microtus mon- 


tanus 6. Rattus norvegicus. 


distal processes is often overlooked. Whereas 
these structures are not as free as are those 
in the cricetids examined by us, their pres- 
ence is obvious (Figure 6). This fusion of 
the lateral processes to the median may rep- 
resent a condition derived from the pattern 
typically seen in cricetines, as some cricetines 
show trends in this development (Figure 7). 

An unusual histological feature of the 
bacula studied is the presence of a synovial 
joint (diarthrosis) between the shaft and 
the distal processes (Figure 8). We have 
observed this in Microtus, Ondatra, Sigmo- 


don, Mesocricetus, and Rattus. Associated 
with this joint, but not included in the scope 
of this report, are tendons and muscles in 
the soft tissues of the glans penis affecting 
the movement of the distal elements. The 
functional morphology and possible adaptive 
significance of this joint and associated struc- 
tures will be reported in a later paper. 

The distal processes are functionally not 
separate entities. They develop from car- 
tilaginous anlagen, as three elements fused, 
or nearly fused, near the synovial joint. The 
distal processes exist essentially as a single 


r 


Figure 7. Cross-section of the phallus of 
Sigmodon hispidus, slightly distal to the 
level of the synovial joint, showing the fu- 
sion of the lateral processes (lp) with the 
median process (mp) near their junction 
with the shaft. 


Figure 8. Longitudinal section through the 
phallus of Microtus montanus showing the 
synovial joint present between the distal 
and proximal elements of the baculum. 


unit, with varying degrees of fusion, culmi- 
nating in the ankylosed condition seen in 
adult Rattus. 

Different degrees of calcification of the 
distal processes are seen in different species. 
It is most complete in the larger forms, or 
large individuals of smaller species. Large 
Microtus montanus develop sequelae. Such 
deposits in this region are visible in Mzcro- 
tus as anteriorly directed “spurs” (Figure 9). 
Extra calcification in the distal processes 
near the region of the synovial joint are evi- 
dent in the illustrations of adult Ondatra 
(15 months of age and older) provided by 


Muroid Bacula 55 


Elder and Shanks (1962). If freedom of 
the synovial joint is essential in the repro- 
ductive activities of these forms, continued 
calcification may mark termination of the 
reproductive activity on the part of the in- 
dividual. On the other hand, since most 
mice have short lives, such a problem may 
be only of academic interest. 

The rod-like baculum of many Nearctic 
cricetines (e.g. Peromyscus, Neotoma, and 
others) is capped by a tip of hyaline car- 
tilage which is adnate with the shaft, but 


ventral lateral ventral 


172mm 


189mm 


Figure 9. Excessive calcification in the 
bacula of large Microtus montanus. The 
“spurs” in the region of the joint between 
the shaft and distal processes are calcium 
deposits. Also note the variation in the 
shapes and angles of the median and lateral 
processes of the two bacula illustrated. The 
total lengths of the animals from which 
the bacula were obtained are given. 


not joined by a synovial joint. This tip is 
possibly homologous with the medial distal 
process of the complex bacular form. Though 
only a small number of such bacula have 
been examined by us, no calcifications or 
ossifications in this distal tip have been 
noted. Hooper (1960) did report that the 
cartilaginous spine (i.e. tip) is one of four 
Ototylomys examined was partly osseous 
(calcified? ). 


B. Development and Individual Variation 


The shaft of the baculum begins to de- 
velop in Rattus when the animal is one-day 
old, and within three days the definitive 
osseous character of the shaft is established 
(Ruth, 1934). The youngest Mzcrotus ex- 
amined by us was 7 days old (72 mm total 
length), and the osseous shaft of the bacu- 
lum was 0.9 mm long. No basal enlargement 
is evident at this stage. By 15 days the basal 
area is well developed and cancellous. Late 


56 Tulane Studies in Zoology 


development does not occur in all rodents, 
however. We have observed prenatal ossi- 
fications in nutria (Myocastor coypus), a 
large hystricomorph possessing a long (25 
mm), simple, rod-like baculum in the adult. 
Such late development in the Muroidea per- 
haps is associated with the general altricial 
condition of the young. 

After the first two weeks the shaft in- 
creases in length and breadth. The diameter 


h) WY 
Al 


Za als 47 210 days 
103-105 128 143 177 mm 


Figure 10. A selected series of bacula of 
Microtus montanus arranged by age and 
total length of the individual from which 
each was obtained, illustrating the general 
pattern of growth. Only calcified and true 
osseous elements are figured. 


TOTAL LENGTH 
LENGTH OF SHAFT 


LENGTH OF BACULUM (MM) 


0 25 50 75 100 


Figure 11. 


125 
KNOWN AGE (DAYS) 
Comparison of the known age of 96 Microtus montanus to the length of 


Voleal2 


of the spine of the shaft increases by active 
periosteal deposition. Calcifications are not 
evident in the cartilaginous distal processes 
until somewhat over one month (with some 
obvious, expected variation). Until calcifica- 
tions occur, the cartilaginous limits of the 
distal processes are not always clearly visible 
in cleared and stained specimens. Calcifica- 
tion of the distal processes and expansion 
of the basal region of the shaft occur rapidly 
after approximately 35 days of age (Figure 
10). All animals examined that were over 
40 days of age had some calcification of the 
distal processes and only one less than 35 
days of age demonstrated calcification. This 
rapid change in the structure of the baculum 
coincides with other changes of an endocrine 
nature occurring at the same time. Calcifica- 
tion of the median process appears to be 
more rapid (in Microtus) than that of the 
lateral elements. Generally by 50-60 days 
calcification of all three processes is under- 
way. 

It is difficult to choose a single measure- 
ment that satisfactorily demonstrates the in- 
crease in size of a complex baculum. Figure 
11 compares the total length of the bacu- 
lum (i.e. maximum length of bone and cal- 


TOTAL LENGTH OF BACULUM (MM)/AGE (DAYS) 
LENGTH OF SHAFT (MM)/AGE (DAYS) 


N = 96 


330 DAYS 


150 175 200 225 250 


the shafts of the bacula (below horizontal interrupted line) and to the total calcified 


length of the baculum (above horizontal interrupted line). 


The vertical interrupted line 


marks the approximate age at which the latter measurement is obtainable. 


TOTAL LENGTH 
LENGTH OF SHAFT 


LENGTH OF BACULUM (MM) 
w 


Muroid Bacula 


i, 


TOTAL LENGTH OF BACULUM (MM)/TOTAL LENGTH (MM) 
LENGTH OF SHAFT (MM)/TOTAL LENGTH (MM) 


| N= 113 


(130 MM) 


70 80 90 100 110 120 


130 


160 


180 


140 150 170 190 


TOTAL LENGTH (MM) 
Figure 12. Comparison of the total lengths of 113 Microtus montanus to the lengths of 


the shafts of bacula 


lengths of the bacula (above horizontal interrupted line). 


(below horizontal interrupted line) and to the total calcified 


The vertical interrupted line 


marks the approximate total length at which the latter measurement is obtainable. 


cified median distal process), and the length 
of the shaft only, against the known age of 
96 Microtus montanus. Little or no change 
can be noted in either measurement after 35 
days of age. The same bacular measurements 
are plotted against the total length of the 
animal (the same known age specimens plus 
several unknown age individuals) in Figure 
12. Although a somewhat closer association 
is seen, the change is slight and much vari- 
ation exists. Separation of individuals into 
age and size groups above 130 mm total 
length, or above 35 days of age is not pos- 
sible utilizing either of these parameters 
(Figures 11 and 12). 


Although simple lengths of the bacula do 
not correlate with known age or total length 
of the individual, subjective differences in 
massiveness and rugosity are evident be- 
tween the bacula of young and old or small 
and large animals. Such impressions have, 
of course, been noted before. Hamilton 
(1946) illustrates 14 bacula of “immature”, 
“subadult”, and “mature” Microtus pennsyl- 
vanicus. Elder and Shanks (1962) illustrate 
similar changes in the bacula of twelve On- 
datra classified as “juvenile” (5-8 months) 


and “adult” (15 months or more) individ- 
uals. Even though the observations concern- 
ing bacular form may be suggestive of juve- 
nile age, Ondatra eight months old may be 
in breeding condition. The animals in their 
“juvenile” class (5-8 months old) were 
trapped in December, and born between 
April and July. Those born earlier in this 
period probably were in breeding condition 
during the latter part of the summer, where- 
as those born in July had far less chance to 
enter the breeding population their first 
year. Not all 5-8 months old Ondatra are 
juveniles, and if, as we suspect, the develop- 
ment of the baculum is controlled in part 
by hormonal factors, chronological age is 
not as important as physiological age. This 
consideration, as Elder and Shanks (1962) 
point out, is often ignored in taxonomic 
studies. 


“It seems unwise for authors comparing 
various species of the Microtinae to claim 
that only the middle, or only the lateral 
digital processes are calcified when only 
3-4 specimens of a species have been ex- 
amined. It also seems likely that disagree- 
ments as to which of the digital processes 


58 Tulane Studies in Zoology 


are calcified at all in a genus such as 

Phenacomys (Dearden, 1958; Hamilton, 

1946), are due to the fact that one man 

has examined bacula of juveniles, the 

other those of adults.” 

Of concern also is the unexplored possi- 
bility that bacular sizes and forms may dif- 
fer within a population as the chronological 
and physiological age composition of the 
population changes. This could occur dur- 
ing a season, a year, or in a Classic microtine 
four year cycle. It would be interesting to 
compare samples of bacula collected from a 
single population at different seasons or 
from year to year. 

A number of attempts were made to meas- 
ure the subjective impression of robustness 
alluded to above, that we, as well as others, 
note in viewing series of bacula from mice 
of different ages and sizes. The most suc- 
cessful approach is the utilization of an in- 
dex, obtained by summing the product of 
the length times the width of the shaft and 
the product of the length of the median 
distal process times that of one (the long- 
est) of the lateral distal processes. Plotting 
such an index against known age reveals 
considerable variation following the critical 


OD 


< 


INDEX 


7 A 
6. 
B . 
5 | = (AB) + (X*Y) * 
4 ° . 
ive . 
ao . 
= sie : 


0 25 50 75 100 


Figure 13. 
indices. 


125 150 
KNOWN AGE (DAYS) 


Comparison of the known age of 97 Microtus 


Volk l2 


35 day old point, indicating that, although 
the index tends to increase with age, the 
curve is not steep enough to allow separa- 
tion of animals 50-75 days old from those 
225 days old (Figure 13). 

Plotting the same indices against total 
lengths of the animals reveals a closer cor- 
relation (Figure 14). The index is seen to 
be closely related to the size of the animal 
but enough individual variation is present 
to preclude separation of the 116 animals 
examined into size groups based on bacular 
index with any practical degree of prob- 
ability. 

Anderson (1960) notes that in Microtus 
ochrogaster, “sexual maturity is reached 
rather abruptly when the total length of most 
individuals is 140 to 150 millimeters.” This 
probably corresponds to the 130 mm size 
we denote as critical in M. montanus. An- 
derson (op. cit.) also notes that maximum 
individual variation would occur in animals 
of this total length (140-150 mm). Our 
data demonstrate, however, that the greatest 
variability is evident in old (circa 225 days) 
and large (above 160 mm) voles (Figures 
13 and 14). 

A further indication that bacular size is 


KNOWN AGE (DAYS) 
N = 97 


330 DAYS 


175 200 225 250 


montanus to their bacular 


Muroid Bacula 


a9 


INDEX / TOTAL LENGTH (MM) 


No. 3 
73 
ra y 
x 
5 A 
ua 
24 


1 = (A-B) + (X-Y) 


N= 116 


70 80 90 100 110 120 


130 


180 


140 150 160 170 190 


TOTAL LENGTH (MM) 
Figure 14. Comparison of the total lengths of 116 Microtus montanus to their bacular 


indices. 


dependent more upon total length than upon 
chronological age of the animal, is sum- 
marized in data presented in Table 2. Data 
on animals of two size classes (160-165 mm 
and 180-189 mm) were selected from the 
known age M. montanus material and known 
age and total lengths were compared with 
the lengths of the bacular shafts and the 
bacular indices. Although the length of the 
shaft was essentially the same in both size 
classes, the bacular index of the larger size 
group was significantly greater than that 
of the smaller group of animals (t—3.85 at 
27 degrees of freedom; significant at .001 
level). Further, the average age of the 160- 
165 mm group was 186 days, whereas that 
of the 180-189 mm group was only 152 
days (Table 2). The small number of ani- 


mals in the respective classes disallows sig- 
nificant statistical results, however. 

In our laboratory stock of Mzcrotus mon- 
tanus, both males and females reach sexual 
maturity at about 5 weeks of age at which 
time the average total length is approxi- 
mately 130 mm. That total length of the 
baculum shows much greater variation after 
35 days of age, suggests that physiological 
factors may influence bacular development 
This is further implied by closer relation of 
the bacular index to body length than to age 
(Figure 12). Apparently, individual dif- 
ferences in physiology and genetics may ac- 
count for the greater variability in bacular 
size once sexual maturity is reached. Per- 
haps the gonadotropic hormones of the 
adenohypophysis or the gonadal hormones 


TABLE 2. 


Comparison of the length of the shaft of the baculum and the bacular index (see text 
for explanation) in two size classes of adult Microtus montanus. 


Size Class Number of Number of Length of 
(Totallength of individuals known-age the shaft of Bacular Index Age (Days) 
the individual) in size class individuals the baculum 
2.3-2.9 mm 3.1-5.5 79-243 
160-165 mm 20 13 (xa 1225) (x = 4.6) (x — 186) 
2.3-3.0 mm 4.4-7.2 105-172 
180-189 mm 9 4 (x= 236) (xa — 5.4) (xX = 152) 


60 Tulane Studies in Zoology 


may exert some influence on bacular de- 
velopment. The general body size attained 
by an individual is regulated largely by 
genetic factors, but individual variations in 
size within a species may well be based more 
on physiological differences. Thus, an in- 
dividual possessing a more active (or larger ) 
anterior pituitary (producing more somato- 
tropin) may grow faster and larger than 
another of its own species. Similarly, a more 
active pituitary might also release greater 
amounts of gonadotropins and release of 
more adrenal androgens may influence the 
possible relationship of bacular growth to 
sexual maturity and total length (as a meas- 
ure of size of the individual) in Mzcrotus. 
Presumably, elucidation of endocrine rela- 
tionships to bacular development can be 
readily accomplished for many mammals by 
experimental procedures in the laboratory 
using known-age animals. 

It is perhaps surprising that endocrine ef- 
fects on such a taxonomically important ele- 
ment as the baculum have not been noted 
by mammalogists before, as they are well 
recorded in the literature. A response in 
baculum size (associated with general mas- 
sive development of all parts of the male 
reproductive tract) in Rattus to androgens 
has been recorded by Korenchevsky et al. 
(1932) and Thyberg and Lyons (1948). 

Howard (1959) referring to gonadectom- 
ized mice (Mws) states: “not only is there 
an increase in lengths of the bone (1.e. bacu- 
lum) with DHA (dehydroepiandrosterone ) , 
but the changes in shape and thickness are 
striking.” A similar response is produced 
by administration of 11-hydroxy-androstene- 
dione (an adrenal androgen) to gonadectom- 
ized mice (Howard, op. cit.). 

These data suggest that chronological age 
cannot be ascertained in Microtws by meas- 
urements of a number of parameters of the 
baculum. We suspect that the same is true 
for other rodents with the complex type of 
baculum. Total bacular size (as indicated 
by the index herein employed) appears to 
be possibly a function of hormonal activity 
and physiological, rather than chronological, 
age. 

Other than differences directly attributable 
to size, considerable individual variation was 
noted in the bacula of M. montanus. Figure 
15 illustrates a series of bacula demonstrat- 
ing the extremes of variability observed in 
the 117 males studied. The base of the shaft 


Vol. 12 


is usually a crudely shaped diamond without 
a basal notch. In some (Figure 15E), a notch 
is present. In others the shape of the base 
varies from roughly triangular (Figure 15D) 
to oblong (Figure 15H), often with an ir- 
regular, rugose proximal edge (Figure 15G). 
The spine of the shaft is more constant in 
form than the base, though occasional medial 
or terminal swellings are evident (Figures 
ISB and 151). The “spurs” or sequelae, 
mentioned above, are often present near the 
synovial joint associating shaft and distal 
processes (Figure 15B and 15J). These 
latter elements are highly variable. The cal- 
cified portion of the median process may be 
simple rod-like (Figure 15C, 1SE, and 15G) 
or may be expanded near its base (Figure 
ISA, I5F, 15H, and 15J). Although this 
expansion is generally associated with greater 
age or total length of the individual, excep- 
tions were noted. 


205 89 days 
17O) | We \ 189 \ 140 mm 
PA 220 days 
175 163 161. mm 
yb j be Wy 
167 days 
180 162 189 mm 
Figure 15. Ten bacula of Microtus mon- 
tanus illustrating individual variation. 


Ages and total lengths of the individuals 
from which the bacula were taken are given 
below the figures. 


No. 3 


The lateral distal processes vary greatly 
between individuals and sometimes between 
members of the same pair. Calcification, 
even in large, adult animals, may be com- 
plete or incomplete, and may, in each proc- 
ess, result from one or occasionally two, 
centers of calcification (Figure 15C). If 
fully calcified, these processes may curve 
inward (Figure 15A and 15G), or remain 
straight (Figure 15D and 15E). The tips 
occasionally curve outward. Viewed laterally 
the lateral processes vary in their relation 
to the median process and the shaft, some- 
times lying in the same plane as the shaft 
or declinating by as much as a 45° angle 
(Figure 9). 

In the Microtus studied, the lateral proc- 
esses are the last to calcify and occasionally 
they may not do so. In large microtines 
(e.g.Ondatra) these elements are large and 
usually well calcified. Pztymys, one of the 
smaller microtines, is often characterized by 
the poor development of these processes. 
Possibly the different degrees of calcification 
seen in a group such as the microtines may 
be more a function of the average or maxi- 
mum size obtained by the form than a 
morphological characteristic, per se. 


Muroid Bacula 61 


C. Os Clitorides in Muroid Genera with 
Complex Bacula 

As homologs of the penis, clitoral ele- 
ments are of interest as they often demon- 
strate what may be interpreted as either 
rudimentary or reduced conditions of the 
male structures. In some rodents, especially 
the sciurids, the os clitoridis is a small, 
clearly homologous, version of the baculum 
(Layne, 1954). This is not the case in the 
muroids examined. 

In muroids the clitoris forms a small rep- 
lica of the penis. The urethra is enclosed 
within the clitoris in Mesocricetus, Ondatra 
(Figures 16 and 17) and Microtus. Distally 
the clitoris terminates in three lobes of tis- 
sue, homologous with the anlagen of the 
three distal processes of the baculum. Car- 
tilaginous tissue is present in these lobes in 
the genera examined. In Ondatra the fibro- 
cartilage of the median lobe calcifies in 
large individuals (Figures 17 and 18A), and 
although we have not observed calcifications 
in the lateral processes, they possibly may 
occur in some individuals. The only other 
microtines in which the os clitoridis has 
been reported are Microtus californicus and 
M. longicaudus (Ziegler, 1961). The illus- 


Figure 16. Cross-section of the clitoris of Mesocricetus auratus showing the true bony 


nature of the os clitoridis (os). 


Figure 17. 


Cross-section of the clitoris of Ondatra 


zibethicus, showing the homologs of the lateral processes of the baculum (lp), and the 
median process with a calcified fibro-cartilage “os clitoridis” (os). The urethra (ur) 


is visible in both Figures 16 and 17. 


62 Tulane Studies in Zoology 


trations of these specimens suggest that they 
are of the same type as that of Ondatra. 
We have examined 21 female Miécrotus 
montanus ranging in total length from 145- 
166 mm, and in age from 212-245 days, but 
have observed no calcification following 
Alizarin Red staining. Fibro-cartilage is 
present in the median lobe, however, and 
under favorable conditions might calcify. 
Ziegler (1961) suggests that the occurrence 
of the os clitoridis in Mzcrotus may not be 
associated with age, as it is found in both 
young and old animals. 

The os clitoridis of Mesocricetus is quite 
different from that of the microtines. In 
Mesocricetus the element is located more 
proximally and has a more definitive shape 
(Callery, 1951). Sectioning reveals that this 
is true bone (Figure 16), histologically iden- 
tical to the shaft of the baculum. Its proxi- 
mal location in the clitoris confirms this 
homology (Figure 18B). No calcifications 
were noted in the three large, loosely car- 
tilaginous lobes of tissue present distally in 
Mesocricetus. 

The “os clitoridis” of Mesocricetus is not 
homologous to those of Ondatra and Micro- 
tus, as each is homologous to a different 
part of the complex baculum. The “os cli- 
toridis” of Mesocricetus is the only one ob- 
served that can properly be termed a bony 
element. 


D. Taxonomic Implications 


The continuing use of the baculum and 
other phallic structures in mammalian, espe- 
cially muroid, systematics, suggests the de- 
sirability of much more information on the 
development, individual variability, micro- 
structure, and physiological and chronolog- 
ical relationships of these elements before 
sound taxonomic interpretations can be 
based on them. 

From the data presented above, bacular 
structures Obviously are subject, at least at 
the population and infraspecific levels, to 
considerable variability. Such observable dif- 
ferences may be dependent upon a plethora 
of variables, including the endocrine state 
of the individual, chronological age, genetic 
background, etc. 

The degree of such variability, and the 
importance of the endocrine state, as well 
as the nature of the calcifications observed 
in the distal processes in this study, cast 
doubt on the utility of minor differences in 


Vol. 12 


ventral lateral 


ventral lateral 


Figure 18. Clitorides of two cricetids, Onda- 
tra zibethicus (A) and Mesocricetus aura- 
tus (B), illustrated in ventral (urethral) 
and lateral views. The “os clitoridis” of 
each is stippled. 


form and size of the complex baculum in 
systematic studies at the lower taxonomic 
levels in those rodents in which it occurs. 
The source of specimens employed in such 
studies also seems to be of considerable im- 
portance. Unfortunately, many specimens 
available in collections, and often used in 
morphological and systematic studies, have 
been aged on such criteria as the condition 
of the pelage and/or the size of the testes 
and epididymides. Whereas such criteria 
may determine “ecologically adult” individ- 
uals (i.e. individuals functioning as sexually 
mature entities in a population), they pro- 
vide no reliable information on the true 
chronological or physiological age of the 


: 


No. 3 


individual. Since only a small percentage 
of rodents seem to achieve full morphologi- 
cal adulthood under natural conditions, 
laboratory colonies of known age animals 
can perhaps provide better material for com- 
parative morphological studies of male re- 
productive organs and systematic studies 
based on these elements than can be obtained 
in the field. 

This does not mean to imply that observ- 
able differences do not exist between the 
bacula of different muroid rodents, particu- 
larly at, and above, the generic level. At 
these levels gross differences in proportions 
and/or dimensions can generally be sub- 
stantiated as has been shown by Hooper 
(1960 and other papers) and Hooper and 
Musser (1964). Even at these levels, how- 
ever, it would seem imperative to under- 
stand something of the development of the 
baculum, or at least to select bacula from 
individuals of large size as these may repre- 
sent the maximum, and therefore character- 
istic development of the form involved, 
reducing the variability caused by the en- 
docrine state, diet, and other factors. 

Above the generic level basic anatomical 
patterns of bacular development and form, 
as well as association with other structures 
of the glans penes should be similar within 
phylogenetically related groups. Within the 
Rodentia such information is currently only 
available within the myomorphs, and the 
similarity of the baculum or the complete 
glans penis in diversely classified muroids 
has been noted for some time. Hamilton 
(1946) compared Oryzomys and Sigmodon 
to the microtines. Hooper and Musser 
(1964) in a study of the glans penes, con- 
sidered cricetids and murids to represent a 
single family (Muridae). Arata (1964), 
studying the male accessory reproductive 
glands, demonstrated that a basic pattern 
existed in murids and cricetids, and sug- 
gested that only one family was represented. 
Hershkovitz (1962) discounted the com- 
monly accepted differences in dental pattern 
between the murids and cricetids and recog- 
nized only a single family (Muridae), pre- 
ferring the evidence afforded by the phallus. 

The similarity of bacular form in Rattus 
and the cricetids examined in this study 
supports the thesis that murids and cricetids 
represent but a single family. The develop- 
ment of the baculum of Rattus described by 
Ruth (1934), and the presence of a movable 


Muroid Bacula 63 


joint between proximal and distal elements 
of the baculum of Rattus and the cricetids 
noted in this report suggests that basic 
homologous morphological forms are repre- 
sented. 

Although all cricetids examined by us have 
calcified fibro-cartilage distal elements as 
contrasted to the bony distal processes of 
Rattus, far too many muroids remain un- 
examined, and little systematic significance 
can be placed on this difference at this time. 


The fusion of the distal elements seen in 
Rattus is greater than that observed in the 
cricetids, but is probably derived from the 
basic cricetid pattern. Hooper and Hart 
(1962) note similar trends in microtines, 
and Hooper and Musser (1964) point out 
that this trend may have occurred several 
times, and is evident in microtines, murines, 
South American cricetines and Old World 
cricetines, producing secondarily simple 
penes, derived from an ancestral complex 
stock. Bittera (1918) previously suggested 
that such reductions were secondary. The 
evidence produced by a study of the male 
accessory reproductive glands (Arata, 1964) 
also suggests that certain glandular comple- 
ments, usually present along with the com- 
plex baculum occurs in muroids (including 
cricetines, microtines, and murines), and is 
variously reduced in different subgroups. 


Thus, the data presented above reinforce 
the importance of the baculum and associated 
phallic structures in studies of muroid ro- 
dents at the generic level and above, and 
suggest caution concerning the utilization of 
the baculum alone at specific and subspecific 
levels in rodents in which the complex type 
is present. 


IV. ACKNOWLEDGMENTS 


The authors thank Mr. J. Howard Hutch- 
ison for drawing Figure 1 and Mr. Larry H. 
Ogren for aid in collecting specimens of 
Ondatra and Myocastor used in this study. 


The senior author carried out part of this 
work under the auspecies of the American 
Cancer Society (Grant No. IN 24-E) and the 
National Science Foundation (GB 2458). 
Mrs. Downs (Martha C. Sapp) participated 
in this study while a recipient of a National 
Science Foundation Undergraduate Research 
Fellowship at Tulane University (Newcomb 
College). Availability of the Mzcrotus mon- 
tanus utilized in this study was made possible 


64 


by support from the National Science Foun- 
dation (188926), U. S. Atomic Energy Com- 
mission (AT-40-1-1831) and the New Or- 
leans Cancer Association. 


V. REFERENCES CITED 


ANDERSON, SYDNEY 1960. The baculum in 
microtine rodents. Univ. Kans. Publ. 
Mus) Nat: Hist. 112): 1822216: 


ARATA, ANDREW A. 1964. The male acces- 
sory reproductive glands of muroid ro- 
dents. Bull. Florida State Mus., Biol. Sci. 
9: 1-42. 

BITTERA, JULIUS 1918. FHiniges iiber die 
mdnnlichen Kopulations-organe der Muri- 
den und deren systematische Bedeutung. 
Zool. Jahrb., Abl. Systematik. 41: 399- 
418. 


CALLERY, R. 1951. Development of the os 
genitalia in the golden hamster, Meso- 
cricetus (Cricetus) auratus. J. Mammal. 
32: 204-207. 

DEARDEN, L. C. 1958. The baculum in La- 
gurus and related microtines. J. Mam- 
mal. 39: 541-553. 

ELDER, W. H. and C. E. SHANKS 1962. Age 
changes in tooth wear and morphology of 
the baculum of muskrats. J. Mammal. 
43: 144-150. 

GILBERT, T. H. 1892. Das os priapi der 
Saugethiere. Morph. Jahrb. 18: 805-831. 

HAMILTON, W. J., JR. 1946. A study of the 
baculum in some North American Micro- 
tinae. J. Mammal. 27: 378-386. 

HERSHKOVITZ, PHILIP 1962. Evolution of 
neotropical cricetine rodents (Muridae) 
with special reference to the phyllotine 
group. Fieldiana: Zoology. 46: 1-524. 

Hooper, EMMET T. 1960. The glans penis in 
Neotoma (Rodentia) and allied genera. 
Occ. Pap. Mus. Zool., Univ. Mich. No. 
GilSieem=2 02 

Hooper, EMMETT T. and B. S. Hart 1962. 


Tulane Studies in Zoology 


Vol. 12 


A synopsis of North American microtine 
rodents. Misc. Publ., Mus. Zool., U. Mich. 
No. 120: 1-67. 

HooPpeR, EMMET T. and Guy G. MUSSER 
1964. The glans penis in Neotropical cri- 
cetines (Family Muridae) with comments 
on classification of muroid rodents. Misc. 
Publ., Mus. Zool., U. Mich. No. 123: 1-57. 


HOWARD, EVELYN 1959. A complementary 
action of corticosterone and dehydroepi- 
androsterone on the mouse adrenal, with 
observations on the reactivity of repro- 
ductive tract structures to dehydroepian- 
drosterone and 11-hydroxy-androstenedi- 
one. Hndocronol. 65: 785-801. 

KORENCHEVSKY, V., M. DENNISON and A. 
KOHN-SPEYER 1932. The rat unit of tes- 
ticular hormone. J. Biochem. 26: 2097- 
2107. 

LAYNE, JAMES N. 1954. The os clitoridis of 
some North American Sciuridae. J. Mam- 
mal. 35: 357-366. 

RuTH, E. B. 1934. The os priapi: a study 


in bone development. Anat. Ree. 60: 
231-249. 

SIMPSON, GEORGE G. 1945. Principles of 
classification and a classification of 
mammals. Bull. Amer. Mus. Nat. Hist. 
88: 1-350. 


TAYLOR, J. MARY 1961. Reproductive biolo- 
gy of the Australian bush rat, Rattus 
assimilis. U. Calif. Pub. Zool. 60(1): 
1-66. 

THYBURG, W. G., and W. R. Lyons 1948. 
Androgen-induced growth of the os pe- 
nis of hypophysectomized-gonadectomized 
rats. Proc. Soc. Exp. Biol. and Med. 69: 
158-161. 


TULLBERG, TYCHO 1899. Ueber das System 
der Nagethiere, eine Phylogenetsche 
Studie. Nov. Acta. Reg. Soc. Upsala, ser. 
3, vol. 18: 329-541. 

ZIEGLER, ALAN C. 1961. 
clitoridis in Microtus. 
101-103. 


Occurrence of os 
J. Mammal. 42: 


ETHEOSTOMA DITREMA, A NEW DARTER OF THE SUBGENUS 
OLIGOCEPHALUS (PERCIDAE) FROM SPRINGS OF THE 
ALABAMA RIVER BASIN IN ALABAMA AND GEORGIA 


JOHN S. RAMSEY 


and 


ROYAL D. SUTTKUS, 
Department of Zoology, 
Tulane University, 

New Orleans, Louisiana 70118 


ABSTRACT 


Etheostoma (Oligocephalus) ditrema 
is described from 183 specimens from 
three localities in the upper Coosa-Ala- 
bama River basin. It is restricted in 
habitat to springs and spring-fed ponds 
above the fall line. It is a small, sexu- 
ally dimorphic species most closely re- 
lated to but sharply differentiated from 
E. swaini of the eastern Gulf Coast- 
al Plain. Infraspecific variation is 
marked. E. ditrema is unusual among 
percids in typically possessing two cor- 
onal pores, which, when considered with 
other characters, suggests that it is a 
paedomorphic species of the H. aspri- 
gene species group. 


The subgenus Oligocephalus is the most 
complex and speciose group of those com- 
prising the North American darter genus 
Etheostoma. The members of the group were 
delimited by Bailey and Gosline (1955), 
who recognized 19 nominal species. Strawn 
and Hubbs (1956) recognized Etheostoma 
lepidum (Baird and Girard) as a species 
distinct from E. grahami (Girard). Yerger 
(1960) resurrected E. okaloosae (Fowler ) 
from the synonymy of E. swaini (Jordan), 
and included it in the subgenus Véllora. 
Etheostoma spilotum Gilbert was reduced to 
a subspecies of E. sagitta (Jordan and Swain) 
by Kuehne and Bailey (1961). Distler and 
Metcalf (1962) described E. pallididorsum, 
which may prove to be a subspecies of E. 
cragimt Gilbert. With the definition of the 
subgenus Oligocephalus and the redescrip- 


tion of E. hopkinsi (Fowler) by Bailey and 
Richards (1963), the number of recognized 
nominal species in the group was brought 
tome 

Etheostoma ditrema was first collected 
by Jordan (1876) in millponds of the region 
of Rome, Floyd Co., Georgia. However, he 
misidentified his specimens as Boleichthys 
elegans Girard, which is probably a synonym 
of E. grahami, a species of southwestern 
United States and northeastern Mexico. 


We discovered the new darter during the 
spring of 1962, in a spring tributary to the 
Coosa-Alabama river system in northwestern 
Georgia. Later another spring locality in 
northeastern Alabama was brought to our 
attention. 


We acknowledge gratefully the assistance 
of the following. Clyde D. Barbour, Wil- 
liam T. Mason, Jamie E. Thomerson, and 
members of the Tulane University Summer 
Program in Environmental Biology for 1964 
aided in the collection of material. Richard 
D. Caldwell and W. Mike Howell (Univer- 
sity of Alabama) apprised us of the existence 
of the Alabama population of ditrema and 
have given information on their collecting 
efforts in springs of northeastern Alabama. 
Dr. Herbert T. Boschung loaned material 
from the University of Alabama Ichthyology 
Collection (UAIC). Dr. Bruce B. Collette 
discovered and notified us of a single speci- 
men of ditrema remaining from Jordan’s 


EDITORIAL COMMITTEE FOR THIS PAPER: 


BRUCE B. COLLETTE, Acting Director, Ichthyological Laboratory, U. S. National Mu- 


seum, Washington, D. C. 


LESLIE W. KNAPP, Supervisor for Fishes, Oceanographic Sorting Center, U. S. Na- 


tional Museum, Washington, D. C. 


GEORGE A. Moore, Professor of Zoology, Oklahoma State University, Stillwater, 


Oklahoma 


66 Tulane Studies in Zoology 


collection in the region of Rome, Georgia. 
He allowed us to examine this specimen 
while he had it on loan from the Academy 
of Natural Sciences of Philadelphia (ANSP). 
Miss Winona H. Welch (De Pauw Univer- 
sity) identified aquatic mosses from the 
type locality. Assistance in field work was 
made through National Institutes of Health 
grants WP-00082-04, 05 and 3-T1-ES-27- 
01S1, 02S1, and National Science Founda- 
tion NSF G-23598 to Suttkus, and NSF 
G-17005 to Ramsey through the Highlands 
Biological Station, Inc., North Carolina. 


Etheostoma (Oligocephalus) ditrema 
new species 
Coldwater darter 
( Figs. 1-3 ) 

Boleichthys elegans—Jordan, 1876: 
309 (misidentification ). 

Material—Description is based on 133 
specimens from three localities in the Coosa- 
Alabama river drainage. The holotype, TU 
35703, an adult male 33.9 mm in standard 
length, was collected in a spring flowing 
into a small tributary to Mills Creek, tribu- 
tary to Chattooga River, 4.3 airline miles 
due west of Lyerly, Chattooga Co., Georgia 
(0.2 miles ENE of the Alabama boundary ), 
on the Broomtown (Ala.)-Foster’s Store- 
Lyerly road (T7S, R11E, Section 28) on 18 
July 1962. Taken with the holotype were 
21 paratopotypes (TU 29153, 15-35 mm 
s.l.). Other paratopotypes were taken 19 
April 1962 (TU 26086, 8: 24-31), 30 
May 1962 (TU 27566, 9: 18-34), 1 June 
1964 (TU 32762, 34: 19-42), and 23 June 
1964 (TU 32981, 43: 20-39). Five para- 
topotypes from TU 32981 have been dis- 
tributed to each of the following institu- 
tions: USNM 198607, United States Na- 
tional Museum; MCZ 43123, Museum of 
Comparative Zoology, Harvard University; 
ANSP 101231, Academy of Natural Sciences 
of Philadelphia; UMMZ 187501, University 
of Michigan, Museum of Zoology; CU 
47872, Cornell University; SU 62401, Stan- 
ford University. 

A paratype (ANSP 20649, 1: 23) was 
collected during the summer of 1876 from 
a millpond (Etowah River drainage) near 
Rome, Floyd, Co., Georgia. 


308- 


Specimens from a third population, not 
designated as type material, were captured 
in Coldwater Creek, tributary to Choccolocco 


Vole 


Creek, immediately below Coldwater Spring 
(T16S, R7E, Section 29), at Coldwater, 5.7 
miles W of Oxford, Calhoun Co., Alabama, 
about 500 yards north of U. S. Highway 78, 
on 28 January 1964 (UAIC 1138, 1: 38), 
1 June 1964 (TU 32746, 9: 26-41), and 31 
August 1964 (TU 34400, 6: 20-32). 

Several series of Etheostoma swaini from 
the Alabama River drainage were used for 
comparison with ditrema. These include 
TU 9497 (2: 43-55), Ala., Montgomery 
Co., creek 12.6 miles east of Montgomery, 
Highway 80; TU 34016 (5: 20-38), Ala., 
Clarke Co., Sand Hill Creek 1.1 miles west 
of Choctaw Bluff: TU 35176 (472 22-43) 
Ala., Dallas Co., Pine Flat Creek 6 miles 
south of Selma. The problem of geographic 
variation in swaimt and in the asprigene 
comp!ex is being reported elsewhere. 

Counts and measurements were made fol- 
lowing Hubbs and Lagler (1958), except 
transpelvic width, the distance between the 
outer bases of the pelvic spines when held 
parallel (Bailey and Richards, 1963). The 
cephalic lateralis canals were analyzed fol- 
lowing Hubbs and Cannon (1935). 


Diagnosts—A_ small, moderately robust 
species of the subgenus Oligocephalus. Lat- 
eral line moderately arched and incomplete, 
pored lateral-line series terminating between 
the level of the posterior base of the spinous 
dorsal fin and posterior soft dorsal base; 
total lateral-line scales 41 to 54, pored scales 
19 to 35, unpored scales 13 to 30. Coronal 
canal incomplete, usually two coronal pores; 
infraorbital canal complete; supratemporal 
canal usually interrupted. Branchiostegal 
membranes overlapping anteriorly. Nape 
naked to completely scaled; breast usually 
scaled, rarely naked; prepectoral region, 
cheeks, opercles, and posterolateral corners 
of top of head scaled. Dorsal fin-rays VIII 
to XII—9 to 12; anal I, 6 to 8; pectoral 11 
to 13. Nuptial tubercles absent. Vertebrae 
35 to 37. Breeding male dark brown with 
orange pigment on belly and lower caudal 
peduncle; female indistinctly mottled with 
dark brown. Submarginal orange band pres- 
ent in spinous dorsal fin of both sexes. 
Humeral dark spot absent. Three dark 
blotches (rarely somewhat ocellate) in a 
vertical series at caudal fin base. 

Description—Etheostoma ditrema is a 
dwarfed species of the subgenus Ol/gocepha- 
lus, The largest specimen available is a 


PF aw —_ 


~ 
SBE ele 
CEL EPR Ga 


ge ee 


Figures 1-3. Etheostoma ditrema, new species. 1. 


A New Darter 67 


(Upper) TU 32762, male paratopo- 


type, 39.0 mm standard length. 2. (Middle) TU 32762, female paratopotype, 31.9 mm. 


3. (Lower) TU 32746, female, Coldwater Creek, 40.7 mm. Photographs by C. 


bour. 


male 42.1 mm in standard length, the larg- 
est female, 40.7 mm. Adulthood is appar- 
ently reached when a standard length of 
25 mm is attained. The body is moderately 
robust but somewhat compressed. The body 
is widest just behind the head, and deepest 
at the level of the pelvic fin insertion, ex- 
cept in gravid females. There is a moderate 
nuchal hump in about half of adult males 
and in a third of adult females. The caudal 
peduncle is moderately slender. These and 


D. Bar- 


other proportional measurements are listed 
in Table 1. 

The head is of moderate length, about 30 
percent of standard length. The snout is 
gently to abruptly decurved and short, its 
length usually less than orbit length. The 
upper and lower profiles of the snout meet 
at an angle of 55° to 85°. The projected 
angle formed by the upper and lower head 
surfaces behind the eye ranges from 19° to 
30°. The frenum is always well-developed, 


68 Tulane Studies in Zoology Vol. 12 
TABLE 1. 
Measurements of Etheostoma ditrema in thousandths of standard length 
TU 26086 TU 26086 
TU 357038 27566, 29153 29153 
Catalog Number Holotype Paratypes Paratypes 
Number of specimens 1 9 10 
Sex 3 3 g 
Range x1 Range x 

Standard length (mm) 33.9 24.9-33.7 (30.4) 26.7-35.3 (31.3) 
Predorsal length 348 346-367 (353) 358-371 (358) 
Anal origin to snout 644 619-656 (641) 634-668 (650) 
Body depth 209 190-208 (199) 190-228 (206) 
Distance from soft dorsal 

origin to anal origin 180 157-175 (169) 149-176 (161) 
Body width 142 121-138 (130) 124-153 (139) 
Caudal peduncle length 233 227-265 (244) 227-272 (245) 
Caudal peduncle depth 106 97-109 (103) 90-111 (100) 
Head length 307 294-312 (320) 280-317 (300) 
Head depth 174 165-177 (fas) 159-180 (166) 
Head width 136 125-145 (si) 129-149 (CLB37()) 
Lower jaw symphysis to 

juncture of gill membranes IPA 115-149 (13:2) 126-152 (136) 
Pelvic insertion to juncture 

of gill membranes 192 167-192 (180) 180-198 (185) 
Orbit length 74 76-89 (80) 72-90 (80) 
Snout length Pal 54-72 (66) 59-75 (65) 
Upper jaw length 86 80-96 (87) 82-95 (87) 
Width of gape 74 72-85 (79) 70-83 (76) 
Interorbital width, least fleshy 50 48-64 (55) 31-54 (50) 
Spinous dorsal base 274 260-289 (276) 252-288 (269) 
Longest dorsal spine 97 85-112 (99) 67-99 (85) 
Soft dorsal base ales 158-197 (LYK) 142-184 (166) 
Longest dorsal soft ray 174 131-159 (143) 127-153 (139) 
Soft dorsal, depressed length 254 218-273 (252) 221-257 (236) 
Longest anal soft ray 142 LAGE 5A (140) 113-138 (128) 
Anal fin base 124 94-136 (ala) 96-115 (107) 
First anal spine 86 69-95 (84) 65-87 (74) 
Anal, depressed length 200 205-230 (216) 192-214 (199) 
Longest pectoral ray 200 187-245 (207) 158-216 (191) 
Pelvic fin length 209 186-223 (265) 173-194 (185) 
Pelvic fin base 32 382-39 (35) 33-39 (36) 
Interpelvic distance 15) 10-16 (13) 10-19 (14) 
Transpelvie width f(a 61-67 (65) 62-72 (66) 
Caudal length 206 190-232 (209) 187-216 (203) 


1 Holotype included in mean for males. 


although frequently narrow. The mouth is 
terminal or slightly subterminal, and_pro- 
jects posteriorly and downward to or slightly 
beyond the anterior edge of the eye. The 
prevomer and palatine bones bear teeth. The 
upper surface of the eye in lateral aspect is 
even with the top of the head. The gill 
membranes are usually separate and over- 
lapping anteriorly, occasionally very slightly 
conjoined. There are six branchiostegal rays 
on each side. 


The lateral line is incomplete, and is ele- 
vated and arched anteriorly, beginning the 
downward arc at about the level of the 


spinous dorsal origin. The pored lateral line 
terminates at the level of a point between 
the posterior spinous dorsal and_ posterior 
soft dorsal bases. 


The infraorbital canal is usually complete 
(interrupted on one side in one of 22 type 
specimens and in two of 16 specimens from 
the Choccolocco Creek drainage; interrupted 
on both sides in one specimen from the 
Choccolocco locality, pores 24-5 - 5-4-2). In- 
fraorbital pores usually number 8 (5 to 9). 
The preoperculomandibular canal is typically 
complete, usually with 10 pores (rarely 8 
or 11, frequently 9). The supratemporal 


No. 3 A New 
canal is usually interrupted, each branch 
having 2 pores (Table 5). The lateral canal 
normally has 5 pores. 

An unusual diagnostic feature is the pos- 
session of two well defined coronal pores 
in most specimens (Table 5), which results 
from the non-fusion of the two coronal 
canals branching mesially from the supra- 
orbital canals. In all other species of Oligo- 
cephalus, and in other percid subgenera, 
these branches fuse to form a_ backward- 
projecting tube terminating at the coronal 
pore. In E. ditrema the two coronal branches 
emerge side-by-side just posterior to a line 
between the upper orbital rims. The two 
pores may fuse as one, but there is rarely a 
tube directed caudad to the pore. There are 
in addition four pores in the supraorbital 
canal, although infrequently one interorbital 
pore is absent. Rarely, one of the coronal 
branches has failed to develop. 

Scale row counts (Tables 2 and 3): total 
lateral-line scales number 41 to 54 (usually 
44 to 50), pored lateral-line scales 19 to 35 


Darter 69 


(usually 22 to 32); unpored lateral-line 
scales 13 to 30 (usually 16 to 26); trans- 
verse body scales (from soft dorsal origin 
posteroventrally to anal fin base) 11 to 14 
(usually 12 or 13); scales above lateral line 
3 to 5 (usually 4); scales below lateral line 
6 to 9 (usually 7 or 8); caudal peduncle 
scales 17 to 22 (usually 19 to 21). 
Squamation: The opercles, cheeks, belly, 
and prepectoral region are wholly invested 
with exposed ctenoid scales. There are a 
few scales embedded on the head just above 
and anterior to the junction of the supra- 
temporal and lateral canals. The breast is 
naked anteriorly. The posterior breast is 
usually scaled, although some infraspecific 
variation exists. The type material from the 
Chattooga and Etowah drainages in Georgia 
usually has exposed ctenoid breast scales. 
Occasionally the scales are embedded, or a 
narrow median strip is naked, but the breast 
is never entirely scaleless. Of the 16 speci- 
mens available from Coldwater Spring, only 
one has exposed ctenoid breast scales, 10 


TABLE 2. 


Distribution of scale row counts in Etheostoma ditrema and E. swaini. 


Value for 


holotype of ditrema in boldface 


Species 
and 
drainage 


Total lateral-line scales 


39 40 41 42 438 44 45 46 47 48 49 50 51 52 53 54 N 


ditrema 


Chattooga Le Lees Or iG 22S el Geena — ne OO 
Etowah 1y— jl 1 
Choccolocco a 3 4 a BY 2 | 1115) 
swaini 
Alabama 1 4 3 2 Se LO 1 52a 44 
Caudal peduncle Soft dorsal origin 
seales to anal base 
17 28 19 20 21 22 N SLD ott 3 lA Ny 
ditrema 
Chattooga 3) Ads sian eo) ao 108 2 Gon 40. e209 
Etowah 1 1 1 1 
Choccolocco 1 i 8 3 1 14 14 1 155 
swaini 
Alabama 1 4S ala lhe lO) 3) 44 i ae lel ell 
Seales above Scales below 
lateral line lateral line 
BE i De IN Grae Oso ll OvaeN 
ditrema 
Chattooga 2) ie) WC 76 Br x0) Bil 7 70 
Etowah 1 il 1 1 
Choccolocco 14 1 a LS) Oe Lbs 
swaini 
Alabama 3) By ty Il All 5) PQ) aly Bal! 


'.! Both sides of single specimen used: r 


= richt, |] = left 


70 


Tulane Studies in Zoology 


Vol. 12 


TABLE 3 (continued on opposite page) 
Lateral line scales in Etheostoma ditrema and EF. swaini. Value for holotype in boldface. 


Species 
and 
drainage 19 20 21 


ditrema 
Chattooga 3 2 2 
Etowah 
Choccolocco 1 1 


swaini 
Alabama 


Pored lateral-line scales 


22 23 24 25 26 27 28 29 


3 8 11 15 12 12 11 
1 2 1 — 2 3 3 


Unpored lateral-line scales 


4 5 6 7 8 


9 10 iil 12 13 14 15 16 


ditrema 
Chattooga 
Etowah 
Choccolocco 


swaint 
Alabama 1 3 9 10 10 


have scattered, embedded ctenoid scales, and 
5 have the breast completely naked. 

Nape squamation is variable (Table 6). 
Specimens from Coldwater Spring tend to 
have the nape more fully scaled than in type 
specimens. The notation used for the de- 
gree of nape squamation in Table 6 was 
derived from a relative scale. 
zero signifies that at least the median por- 
tion of the nape from the spinous dorsal 
origin to the occiput is naked; I through II 
represent successive increases in posterior 
nape squamation; IV, nape wholly scaled but 
scales embedded at least anteriorly; V, nape 
completely invested with exposed scales. 

Fins (measurements in Table 1): The 
spinous dorsal is composed of 8 to 12 
slender spines. Many specimens have small 
postapical fleshy enlargements at the spine 
tips similar to those in other species of 
Oligocephalus. The fin is low; the length 
of the longest spine (located at the fin cen- 
ter) is about two-fifths to one-half the 
length of the fin base, and can be stepped 
into head length two and one-half to three 
times. The fin border in both sexes usually 
forms a gentle arc rearward to the dorsum 
(not subquadrate in outline, as in E. swainz). 
The soft dorsal fin is usually well separated 
from the spinous dorsal (as in Fig. 2). 
There is typically a much broader hiatus be- 
tween the fins in the Choccolocco population 
(Fig. 3). Though low, the soft dorsal is 
higher than the spinous dorsal. Dorsal soft 
rays number 9 to 12. Total dorsal rays range 


A value of 


from 18 to 23. The Choccolocco population 
has fewer dorsal rays (Table 4), which 
probably is correlated with the greater dor- 
sal fin separation. 

The anal fin is also small. There are usu- 
ally two spines (one specimen out of 133 
has a single spine, and two have three 
spines). The second spine is usually more 
slender than the first. The second spine in 
the Choccolocco population is usually stiff, 
but is typically very slender and flexible in 
specimens from Georgia. Anal soft rays 
number 6 to 8 (usually 7). 

There are 11 to 14 (usually 12 or 13) 
branched caudal rays. The posterior edge of 
the caudal fin is usually truncate, frequently 
slightly emarginate or convex. The pectoral 
fins are short and rounded, the longest ray 
about two-thirds of head length. Left pec- 
toral rays number 11 to 13 (usually 12). 
The pelvic fins (rays I, 5) usually extend 
beyond the posterior edge of the pectoral 
fin, and are inserted very close together. 
Interpelvic distance is less than half the 
width of the pelvic fin base. 

Analysis of radiographs of 35 specimens 
from the type locality revealed the following 
vertebral counts: 35 vertebrae (one speci- 
men), 36 (17), and 37 Cli): 

Coloration of males—The most conspicu- 
ous feature of nuptial males is the somewhat 
muted red-orange pigmentation of the 
lower body. In several male paratopotypes 
captured on 1 June 1964, this pigment was 
distributed almost uninterruptedly from just 


p> ae. 


No. 3 A New Darter 71 
TABLE 3 (continued) 

4 [5 Pored lateral-line scales > 
30 Sl 32 Bs 34 35 36 37 38 39 40 41 42 43 N 
7 5 8 2 — 1 109 
1 
— 1 15 
2 2 a 4 3 2 7 5 6 3 2 — al 44 

Unpored lateral-line scales 

LY 18 19 20 Dall 22 23 24 25 26 Pat | 28 29 30 N 
5 19 5 18 19 Lil 3 6 1 5 3 — — 1 109 
HES ee 1! 1 
4 — — a1 3 4 — 2 —_ 1 15 
44 


behind the pectoral base to immediately pos- 
terior to the anal fin origin, and on the lower 
caudal peduncle in the form of about five 
indefinite bar-like groupings of orange 
scales separated by dull olive-green bars. 
The orange pigmentation on the caudal pe- 
duncle extended dorsad only to the level of 
the lateral line. Other males had orange pig- 
ment before the vent only. Two to four 
upper body scales in some males also bore 
orange pigment, but these were scattered 
and inconspicuous. 

In life, and in alcohol, the dorsum is usu- 
ally uniformly dark brown, broken in most 
by a predorsal buff-colored nuchal patch of 
varying width. In some there are about nine 
very ill-defined darker saddles crossing the 
dorsal midline and extending laterad on 
about two scale rows to either side. The 
intermediate areas between the saddles are 
brown, similar to the background color, but 
occasionally are a light brown or buff color. 
The body at the base of each dorsal fin is 
buff. In some, the centers of the exposed 
fields of scales of the dorsum have a slightly 
darker brown color, giving the impression 
of vague longitudinal lines extending from 
the sides of the occiput to the posterior soft 
dorsal base. The striped pattern extends 
downward (excluding the lateral line) to 
the anal base. The stripes are irregularly if 
at all developed on the lower body, generally 
being limited to an area on the lateral belly 
anterior to the anal fin origin and for a 
short distance on the lower body above the 


anal fin. There is no humeral dark blotch. 
The lateral line is less pigmented along the 
pored portion than on adjoining areas, and 
appeared yellowish in life, somewhat as in 
E. parvipinne Gilbert and Swain. The un- 
pored lateral-line series appears as an ir- 
regular light line. Very faint lateral bars 
(dull olive-green in life) showing some con- 
nection with the dorsal dark saddles are 
present in many individuals. 

There are three black spots (sometimes 
connected) in a vertical series at the caudal 
base. Occasionally the lower and/or median 
spots are faint or absent. The central spot 
lies at the termination of the lateral-line 
series just at or immediately behind the pos- 
terior edge of the hypural plate. The upper 
and lower spots lie at the bases of the pos- 
terior procurrent caudal rays. The caudal 
base between the spots is usually lighter than 
on adjoining areas of the peduncle, and in 
life there was a small spot of red-orange 
immediately posterior and mesial to the 
upper and lower basicaudal dark spots. 

The genital papilla and anal rugae are im- 
maculate white. The genital papilla in males 
takes the form of a short subquadrate flap 
extending posteriorly to the base of the 
first anal spine. Occasionally a median short 
fingerlike projection extends beyond the 
shorter lateral portions of the papilla. 

The lower belly is evenly stippled with 
micromelanophores. The breast has larger 
melanophores distributed to the gular region. 
There is a prepectoral dark blotch. 


72 Tulane Studies in Zoology 


The head dorsum to the snout is dark 
brown. The upper snout was buff-colored 
in life. A dark diffuse line extends from the 
anterior edge of the orbit below the nostrils 
to the snout tip, expanding on the anterior 
third of the upper lip to either side of the 
buff-colored frenum. The remainder of the 
upper lip has one or two dark blotches. The 
posterior maxillary is darkened. The lower 
lip and lower jaw rami are mottled, and the 
mandibular symphyseal region usually has a 
dark blotch. The gular region and branchio- 
stegal membranes are diffusely stippled. 
There is a postorbital dark streak. The sub- 
orbital bar is well-developed, beginning be- 
hind the lower orbital midpoint and curving 
downward and slightly forward on the cheek. 
The iris was golden-orange in life. 


The spinous dorsal fin in life was bor- 
dered by a narrow dusky blue band. Proxi- 
mal to this was a band of red-orange, about 
three times as wide as the marginal band 
anteriorly, tapering to an equal width pos- 
teriorly. Below this was a slightly wider 
dusky blue band extending almost to the 
base of the fin. There was a basal spot of 


Vola2 


dark red behind each dorsal spine. Nuptial 
males have melanophores irregularly dis- 
tributed on the spines. 


The soft dorsal fin was dusky blue through- 
out, always having a basal spot of dark red 
behind each ray. There was usually some 
red-orange arranged in one or two indefi- 
nite narrow bands mesially and submargin- 
ally. There are three or four dark blotches 
on the rays. 

The anal fin was dusky blue-green on both 
the spined and soft-rayed portion, with basal 
red-orange spots on the membranes between 
the soft rays. Some nuptial males had a 
median band of orange on the rays. Others 
had several quadrate dark blotches on yel- 
lowish rays. The edge of the fin was 
colorless. 

The caudal fin has five to seven irregular 
dark bars (pigment on rays only). Between 
the dark bars the rays are yellowish. In a 
few individuals, the basal portion of the 
central rays had red-orange pigment extend- 
ing two-thirds of the distance toward the 
fin edge. The anterior procurrent caudal 
rays are embedded in opaque whitish tissue. 


TABLE 4. 


Distribution of fin-ray counts in Etheostoma ditrema and E. swaini. 


Value for 


holotype in boldface. 


Species Dorsal spines Dorsal soft rays 
and 
drainage 8 OS Oeetel eel 2 N 9 10 11 12> snare N 
ditrema 
Chattooga Wl by te ala BO) ely i 112 
Etowah 1 1 1 1 
Choccolocco 6 9 1 16 i 8 “i 16 
swaint 
Alabama ihe Wal ye 44 119, 23 in 1 44 
Total dorsal rays 
18 19 20 PAA 22, Ze 24 25 N 
ditrema 
Chattooga 1 2 48 44 if iLL 
Etowah if! 1 
Choccoloecco 6 3 7 16 
swaini 
Alabama it 9 21 Lal 1 1 44 
Anal soft rays Left pectoral rays 
6 7 8 N Lal 12 Le 14 N 
ditrema _ ral 
Chattooga 40 66 6 2 3 36 29 65 
Etowah i 1 1 il 
Choccoloceco 5 et 16 10 5 155 
swaini 


Alabama 6 ayil 7 44 


A New Darter Ws 


TABLE 5. 
Supratemporal canal and coronal pores in Etheostoma ditrema and E. swaini. 
Value for holotype in boldface. 


Species 
and Supratemporal canal Coronal pores 
drainage Complete Interrupted N 1 2 
ditrema 
Chattooga 30 86 116 45 68 latts 
Etowah 1 1 il 1 
Choccolocco 5 ill 16 8 8 16 
swaint 
Alabama 20 24 44 44 44 


The pectoral fins are colorless save for a 
scattering of dusky along the entire length 
of the rays. 

The tissue investing the pelvic spine is 
only very slightly thickened, and is colorless 
save for a sprinkling of micromelanophores. 
The soft-rayed portion had dusky blue-green 
(darkest between the posterior rays) along 
the basal two-thirds of the rays and inter- 
radial membrane. The distal third of the 
membrane is colorless. The distal portions 
of the rays have scattered melanophores. 

Only two young males are available from 
the Choccolocco locality. These had sub- 
marginal and basal red-orange bands in the 
spinous dorsal fin, but lacked the orange 
pigment on the venter. 

Coloration of females—Females were de- 
void of erythric pigment on the body. In 
alcohol the general body coloration is similar 
to that of males, save they tend to be more 
mottled, especially on the venter. Chocco- 
locco females are darker and less mottled, 
and occasionally the basicaudal dark spots 
are somewhat ocellate (Fig. 2 and 3). 

Only one female from the Chattooga pop- 
ulation had a submarginal pale orange band 
in the spinous dorsal, but all adult females 
from the Choccolocco locality possessed this 
coloration. Females usually have a dusky 


marginal band, which tends to be obsolete 
anteriorly. There are brownish streaks in 
the median interradial membranes along the 
spines. Dusky spots occur basally in the 
interradial membranes. The spines are vari- 
ously marked with one or two elongate dusky 
blotches. 

The soft dorsal fin is marked with four or 
five indefinite bands of brownish pigment, 
which is distributed on the interradial mem- 
branes distally and on the rays basally. There 
is a basal series of interradial dark blotches. 
The soft dorsal bands are more discrete and 
narrower in Choccolocco females. 

The caudal fin is barred with five to seven 
irregular rows of dark pigment. The anal fin 
bears one to three vague dusky brown series 
of blotches on or adjacent to the rays. The 
pectoral fin is pigmented as in the male. The 
pelvic fins are colorless or have scattered 
melanophores. 

The immaculate, slightly crenulate genital 
papilla of the female projects posteriorly to 
the base of the first anal spine, and is as 
long as or slightly longer than broad. 

Coloration of juveniles—Juveniles are 
generally more lightly pigmented than 
adults. The smallest individuals have moder- 
ately well-defined dorsal saddles and lateral 
blotches. 


TABLE 6. 
Squamation of nape in Etheostoma ditrema and E. swaini (see text for explanation of 
symbols). Value for holotype in boldface. 


Species 
and Degree of nape squamation 
drainage 0 I I IV V N 
ditrema 
Chattooga 24 13 16 8 6 8) 76 
Etowah il 1 
Choccolocco i — — — 6 9 16 
swaini 
Alabama 25 5 3 fl 10 44 


74 Tulane Studies in Zoology 


Infraspecific variation—The single speci- 
ment of E. ditrema from the Etowah drain- 
age of Georgia is apparently of the same 
genetic stock as specimens from the type 
locality in the Chattooga drainage. Members 
of the Choccolocco population differ mark- 
edly in several respects: they have the nape 
more often fully scaled (Table 6); the breast 
tends to be naked or weakly scaled; the fe- 
males are darker and less mottled than Chat- 
tooga females, and more consistently possess 
an orange submarginal band in the spinous 
dorsal; the basicaudal dark spots occasionally 
are ocellate; the second anal spine is stronger. 
The most striking difference is that the 
Choccolocco population has a reduced num- 
ber of dorsal rays. If a separation point in 
Table 4 is determined as being between 20 
and 21 total dorsal rays, the average diver- 
gence between the Choccolocco population 
and the Etowah and Chattooga population 
is about 94 percent. Concurrently, the dor- 
sal fin bases are more widely separated. 
These observations suggest that the number 
of dorsal fin rays has been secondarily re- 
duced, and that the Choccolocco race is a 
derivative of a common stock which has 
been preserved in a more primitive state in 
the upper Coosa area. 

The Choccolocco population likely repre- 
sents a genetically valid subspecies, but we 
hesitate to designate it as such in view of 
the dearth of specimens and lack of knowl- 
edge of distribution of ditrema throughout 
the Coosa drainage. There may be a clinal 
type of variation in probable spring popula- 
tions of the area surrounding the nearly 60 


Vol. 12 


airline miles between Lyerly, Georgia and 
Coldwater, Alabama. In opposition to this 
view, Mr. Richard D. Caldwell of the Uni- 
versity of Alabama informs us that E. di- 
trema was absent from numerous collec- 
tions made by him in springs of northeastern 
Alabama. 

Relationships—The subgenus Oligoceph- 
alus retains in part the diversity of composi- 
tion formerly possessed by the catch-all darter 
genus Poecilichthys (now a synonym of 
Etheostoma s.s.). Although evaluation of 
evolution within Oligocephalus is confused 
by many secondarily developed characters in 
the species, it is clear that EF. ditrema is 
closely allied with the E. asprigene species 
group. Members of this group are E. as- 
prigene (Forbes), E. swaini, E. ditrema, 
and an undescribed species from the Black 
Warrior-Tombigbee drainage in Alabama. 
These forms share the following character- 
istics; nuptial tubercles absent; opercular 
membranes overlapping or scarcely con- 
nected; body robust at the level of the spin- 
ous dorsal origin; supratemporal canal usu- 
ally or frequently interrupted (much _vari- 
ation in swatnt and asprigene); lateral line 
slightly to moderately arched anteriorly; 
humeral blotch not enlarged, inconspicuous 
or absent (usually distinct in swatnz); color 
pattern of red-orange and blue or olive-green 
on the lower body, red-orange and blue in 
dorsal and anal fins of males; 35 to 39 
vertebrae. 

Collette (in press) has found the presence 
and distribution of breeding tubercles among 
percids to be of systematic significance. The 


TABLE 7. 


A comvarison of Etheostoma ditrema and EF. swaini from the Alabama River basin. 


Character 


Species 


ditrema 


swaini 


Snout shape 
Spinous dorsal fin 
n 


Greatest known size (s.1.) 
Horizontal streaks on body 
Dorsal saddles 

Breast 

Prepectoral region 


Left pectoral rays 

Coronal canal 

Lateral line contour 
Pored lateral-line scales 
Unpored lateral-line scales 
Seales above lateral line 


Decurved, blunt 

Spines slender, short; 
posterior edge gently 
curved and diagonal 
to body 

42 mm 

Absent or indistinct 

Absent or indistinct 

Usually sealed 

Exposed ctenoid scales 


Mode at 12 

Incomplete, usually 2 pores 
Moderately arched 

19-35 

13-30 

Mode at 4 


Produced, acute 

Spines thicker, longer; 
posterior edge abruptly 
curved and nearly 
perpendicular to body 

55 mm 

Distinct 

Distinct 

Naked 

Naked or with embedded 
cycloid scales 

Mode at 13 

Complete, a single pore 

Slightly arched 

31-43 

4-12 

Mode at 5 


No. 3 


asprigene species group forms a_ natural 
group among atuberculate species of Olzgo- 
cephalus. Others which appear most closely 
related are E. exile (Girard), E. grahami, 
E. lepidum, and E. pottsi (Girard). Etheo- 
stoma mariae (Fowler) and E. juliae Meek 
also lack tubercles, but on the basis of mor- 
phology and pigmentation do not appear as 
closely related to the asprigene group. 

Etheostoma asprigene comprises a com- 
plex whose most easterly range along the 
Gulf Coast is in tributaries of the lower 
Mississippi River in Louisiana and Missis- 
sippi. Etheostoma swaimi ranges from the 
Amite River drainage of Louisiana and Mis- 
sissippi eastward below the fall line to the 
Apalachicola River drainage of Florida and 
Georgia (Bailey, Winn, and Smith, 1954). 

Etheostoma ditrema appears to be a 
highly specialized derivative of swaini stock 
which early surmounted the fall line in the 
Coosa River system. The nature of the char- 
acters by which ditrema is distinct from 
swaini suggests that ditrema has diverged 
through genetic fixation of developmental 
traits which in darters are associated with 
neoteny. Collette (1962) discussed appar- 
ently neotenic populations of E. (Hololepis) 
fusiforme (Girard), which are characterized 
by reduction in adult size, decrease in rela- 
tive number of pored lateral-line scales, and 
incomplete development of cephalic canals. 
All of these characters are found in ditrema 
as compared with swaini. Collette (1962) 
found reduction in development of the coro- 
nal canal in a neotenic population of fzsz- 
forme, but did not report as great a degree 
of reduction as that present in ditrema, in 
which the coronal branches usually do not 
fuse at all. The assemblage of characters in 
which E. ditrema seems a paedomorphic 
species have probably arisen through adapta- 
tion to the cold spring environment, to 
which the species presently appears re- 
stricted. 

Other species of Oligocephalus inhabiting 
the Alabama River system include E. par- 
vipinne and E. whippli artesiae (Hay), 
which have the lateral line complete or 
nearly so, and possess moderately conjoined 
opercular membranes. Etheostoma  parvt- 
pinne apparently occurs only on the Coastal 
Plain. Etheostoma whipplii occurs above 
and below the fall line, but has never been 
collected with ditrema. 

Etheostoma ditrema resembles species of 


A New Darter WD 


the subgenus Hololepis in the configuration 
of the lateral line. Two species of Hololepis 
are reported from the Alabama River sys- 
tem, including E. fusiforme barratti (Hol- 
brook) and E. zontferum (Hubbs and Can- 
non), and a third, E. gracile (Girard), is 
known from the Tombigbee River system 
(Collette, 1962). In the Mobile Bay system 
these occur only on the Coastal Plain. They 
differ from E. ditrema in possessing nuptial 
tubercles and in lacking red-orange body 
pigmentation in breeding males. The lateral 
line is more highly arched in Hololepis spe- 
cies. The moderately arched lateral line in 
E. ditrema seems to be a secondary special- 
ization, and its similarity to that of Holo- 
lepis almost certainly represents convergence 
(probably as does the somewhat arched 
form of the lateral line in E. exile). 

Etheostoma (Psychromaster) trisella Bailey 
and Richards is known from a unique speci- 
men collected about midway between two 
of the known localities of ditrema. Re- 
peated efforts by several groups to collect 
further specimens have been futile.  Al- 
though the specimen is distinct in possessing 
a single weak anal spine, three intense dor- 
sal saddles, and a complete lateral line, it is 
possible that the type of ¢rzsella is an aber- 
rant hybrid between ditrema and another 
darter. This is rather tenuously suggested by 
the generally blotched color pattern, the 
overlapping opercular membranes, and pres- 
ence of two coronal pores in ¢risella (which 
the authors mentioned was a probable anom- 
aly, but which is the usual condition in 
ditrema ), as well as its apparent absence 
in the region today. It is understandable 
that a large-stream form such as E. (No- 
thonotus) acuticeps Bailey might be collected 
only rarely, but all habitats (mainly springs 
and small streams) of the region in which 
trisella might occur have been surveyed in- 
tensively. 

Habitat and life history—E. ditrema 
has been collected recently only in or near 
large springs. We suspect that the “mill- 
ponds” in which Jordan (1876) found speci- 
mens were springfed impoundments, as the 
region of Rome, Georgia has many large 
springs. 

The spring at the type locality boiled from 
a bed of dolomitic limestone at a rate of 
about 30 cubic feet per second. The water 
was cold (16 to 18 C), colorless, and was 
clear even after heavy rains had roiled neigh- 


76 Tulane Studies in Zoology 


boring streams. The bottom was composed 
of a deep bed of soft whitish clay overlaid 
by detritus and a dense growth of aquatic 
mosses (Fontinalis filiformis and Fissidens 
debilis). The greatest depth of water was 
about two meters. The spring pool was 
about 15 m in diameter, and was surrounded 
by brush and open woods. An abrupt break 
in habitat type occurred with the beginning 
of moderate flow at the head of the gravelly 
effluent stream, which was about 2 m wide 
and choked in place with submerged Spar- 
ganium americanum. 


E. ditrema was the only darter present 
in the spring pool. It was always associated 
with dense aquatic vegetation, and individ- 
uals could occasionally be seen perching at 
the surface of moss clumps. It was most 
commonly captured in less than a meter of 
water, but was also taken as deep as 1.3 m. 


Associated fish species in the spring pool 
at the Chattooga locality included Esox 
americanus, E. niger, Minytrema melanops, 
Moxostoma duquesnet, Notropis chrosomus, 
N. lirus, Semotilus atromaculatus, Ictalurus 
melas, Lepomis cyanellus, Micropterus s. sal- 
moides, and Cottus carolinae zopherus. In 
the effluent stream, the above were taken 
(except for E. ditrema ), as well as Hypen- 
telium etowanum, Campostoma anomalum, 
Notropis c. chrysocephalus, N. xaenocepha- 
lus, Rhinichthys atratulus, Lepomis m. mega- 
lotis, Micropterus coosae, Etheostoma (Ulo- 
centra) coosae, and Percina caprodes car- 
bonarta. 

As Coldwater Spring is the chief water 
supply for the city of Anniston, Alabama, 
we were forced to collect in Coldwater 
Creek just below the spring overflow. The 
spring flows from a thrust in the Weisner 
Quartzite formation, and yields 32 million 
gallons per day. The flow in Coldwater 
Creek was estimated at 100 cfs. The water 
was clear, colorless, and cold (18 C). 
Etheostoma ditrema was the only darter 
present, and was taken from dense silted 
patches of Myriophyllum growing in pro- 
tected pockets along the left stream edge 
(right edge was polluted from a tributary 
a short distance below). Several specimens 
were captured in a muddy ditch near its 
junction with Coldwater Creek. 

Associated species at the Coldwater lo- 
cality were Lampetra aepyptera, Esox amert- 
canus, E. niger, Gambusia affinis, Lepomis 


Vol. 12 


cyanellus, L. macrochirus, and Cottus caro- 
linae zopherus. 


Jordan (1876) took Notropis  lirus, 
Etheostoma stigmaeum, and Percina n. nigro- 
fasciata with E. ditrema. 


Males had assumed nuptial coloration by 
the end of April. They were still brightly 
colored in mid-July. It is probable that 
bright coloration is maintained year-round. 

Females were gravid in collections made 
in April through July, but were largely spent 
by the latter date. Coldwater females were 
greatly swollen with eggs on June 1 (Fig. 

but did not yield eggs when gently 
pressed. Ovarian eggs were large and few 
in number. Chattooga females had eggs of 
an average diameter of 1 mm on June 1, 
and 1.2 mm on June 23. One at 40.5 mm 
s..1. had 25 large ova in the left ovary and 
19 in the right. Another at 33.1 mm _ had 
23 (left) and 14 (fight). A third vat {3ie/ 
mm had 23 ripe eggs in the right ovary. 
The smallest gravid female was 24.4 mm 
long. 

The smallest young available (15.2 mm 
sl.) was taken at the Chattooga locality on 
18 July. Spawning likely occurs throughout 
the month of June. 


The name ditrema refers to the typical 
possession of two coronal pores. 


LITERATURE CITED 


BAILEY, R. M., and W. A. GOSLINE. 1955. 
Variation and systematic significance of 
vertebral counts in the American fishes 
of the family Percidae. Misc. Publ. Mus. 
Zool. Univ. Michigan 93: 1-44. 

, and W. J. RICHARDS. 
1963. Status of Poecilichthys hopkinsi 
Fowler and Etheostoma trisella, new spe- 
cies, percid fishes from Alabama, Geor- 
gia, and South Carolina. Occ. Pap. Mus. 
Zool, Univ. Michigan 630: 1-21. 

—., H. B. WINN, and Gagc: 
SMITH. 1954. Fishes from the Escambia 
River, Alabama and Florida, with eco- 
logic and taxonomic notes. Proc. Acad. 
Nat. Sei. Philadelphia 106: 109-164. 


COLLETTE, B. B. 1962. The swamp darters 
of the subgenus Hololepis (Pisces, Perci- 
dae). Tulane Stud. Zool. 9(4): 115-211. 


. In press. The systemat- 
ic significance of breeding tubercles in 
fishes of the family Percidae. Proc. U.S. 
National Mus. 

, and R. W. YERGER. 1962. 
The American percid fishes of the sub- 
genus Villora. Tulane Stud. Zool. 9(4): 
2138-230. 


No. 3 


DISTLER, D. A., and A. L. METCALF. 1962. 
Etheostoma pallididorsum, a new percid 
fish from the Caddo River system of Ar- 
kansas. Copeia 1962(3): 556-561. 

Huss, C. L., and M. D. CANNON. 1935. The 
darters of the genera Hololepis and Vil- 
lora. Mise. Publ. Mus. Zool. Univ. Michi- 
gan 30: 1-93, 3 pl. 

a , and K. F. LAGLER. 1958. 
Fishes of the Great Lakes region. Cran- 
brook Inst. Sci. Bull. 26: 1-213, 44 pls., 
251 figs. 

JORDAN, D. S. 1876. A partial synopsis of 
the fishes of upper Georgia. Ann. Lye. 


A New Darter Wil 


Nata Hast. Ne. 1 807s. 

KUEHNE, R. A., and R. M. BAILEY. 1961. 
Stream capture and distribution of the 
pereid fish EH theostoma sagitta, with geo- 
logic and taxonomic considerations. Co- 
peta 1961(1): 1-8. 

STRAWN, K., and C. Hupps. 1956. Observa- 
tions on stripping small fishes for experi- 
mental purposes. Copeia 1956(2): 114- 
116. 

YERGER, R. W. 1960. Htheostoma okaloosae 
(Fowler), a percid fish endemic in north- 
west Florida. Bull. Assoc. Southeastern 
Biol. 7(2): 41 (abstract). 


June 23, 1965 


PARASITES FROM LOUISIANA CRAYFISHES 
FRANKLIN SOGANDARES-BERNAL, 


Department of Zoology, 
Tulane University, 
New Orleans, Loutsiana 


ABSTRACT 


Two microsporidians, Thelohania sp. 
and ? Plistophora sp., and eight trema- 
todes, Crepidostomum cornutum, Gor- 
godera amplicava, Microphallus opacus, 
M. progeneticus, Maritrema obstipum, 
Macroderoides typicus, Ochetosoma sp., 
and Paragonimus kellicotti, are report- 
ed from crayfishes in Louisiana. The 
presence of the metacercariae of P. kel- 
licotti is of particular interest since the 
crayfishes in which this parasite is 
found are eaten by humans in Louisi- 
ana. 


INTRODUCTION 


Nine species of crayfishes have been ex- 
amined for parasites during studies of para- 
gonimiasis in Louisiana from 1959-1964. 


METHOD OF PROCEDURE 


Crayfishes were collected by the most ex- 
pedient methods and usually transported to 
my laboratory for examination. The live 
specimens were usually identified by the 
late Doctor G. H. Penn, Department of 
Zoology, Tulane University, or identified 
with the aid of a key by Penn (1959). The 
crayfishes were kept in aquaria or finger- 
bowls until they were decapitated and ex- 
amined. The muscles and internal organs 
were separated and carefully teased apart 
with dissection needles while viewed through 
a binocular stereoscopic microscope. Most 
parasites were studied alive under a binoc- 
ular compound microscope. Specimens not 
discarded were fixed in Alcohol-Formalin- 


* Supported in part by a research grant 
(AI 038386 TMP) from the National Insti- 
tutes of Health. 


Acetic solution, stained in Van Cleave’s 
Combination Hematoxylin (Van _ Cleave, 
1953), and mounted in Permount (Fisher 
Sci. Co., N. Y.). The parish of each locality 
is mentioned the first time the locality is 
cited in the text. 


FINDINGS 
Protozoa 
Microsporidia, Nosematidae 
1. Thelohania sp. 
( Figs. 1-4) 
Host: Cambarellus shufeldti (Faxon, 1881) 
Location: Body musculature 
Localities: Chacahoula (Terrebonne Par. ) 
and near Covington (St. Tammany Par.), 
Louisiana 


Discussion: Sogandares (1962a) reported 
this Thelohania sp. from a C. shufeldti col- 
lected at Chacahoula, Louisiana. Since that 
time several additional natural infections 
have been found in the same host species 
near Covington, Louisiana. Sogandares 
(1962a) believed his record to be the first 
for a microsporidian in North American 
crayfishes. This belief was in error, since 
Sprague (1950) named in an abstract, The- 
lohania cambart from Cambarus bartoni 
from streams along the Georgia-North Caro- 
lina border. He reported that the sporont 
(pansporoblast of other authors) of T. 
cambart gave rise to eight spores which aver- 
aged 4.6 microns long by 2.2 microns in 
greatest width, were somewhat oval in shape, 
being broadly rounded at both extremities, 
tapered slightly from anterior to posterior, 
and lacked a persistent sporont membrane. 


EDITORIAL COMMITTEE FOR THIS PAPER: 


HORTON H. Hosps, JR., Senior Research Scientist, Department of Zoology, U. S. 
National Museum, Washington, D. C. 


HAROLD W. MANTER, Professor of Zoology, University of Nebraska, Lincoln, Ne- 


braska 


MARY HANSON PRITCHARD, Research Associate, Department of Zoology and Physi- 
ology, University of Nebraska, Lincoln, Nebraska 


80 Tulane Studies in Zoology 


The polar filament was reported to be 80- 
90 microns long. 

Thelohania sp. from Cambarellus shufeldti 
had pansporoblasts 6-9 microns in diameter, 
which as a preterminal product contained 
eight sporoblasts. Each sporoblast formed 
one spore, resulting in eight spores sur- 
rounded by the pansporoblast membrane. 
Live spores measured from 3.0 to 3.5 mi- 
crons long by 1.2 to 1.6 microns wide. Polar 
filaments about 15 microns long observed in 
3 spores were in all probability only partially 
extruded. 

The Louisiana Thelohania from C. shu- 
feldti probably represents a different species 
from T. cambari since the spores differ in 
size and the pansporoblast membrane of the 
former is persistent. Thelohania contejeant 
Henneguy and Thelohan, 1892, the only 
European species of Thelohania from cray- 
fishes, has a spore 2 to 3 microns long. Thus, 
T. sp. from Louisiana has spores which are 
intermediate in size between more of T. 
cambart and T. contejeani. The specific 
identity of the Louisiana Thelohania from 
C. shufeldti awaits information regarding the 
filament length and life-history, but low in- 
cidence of natural infection makes the neces- 
sary study difficult to complete. 


2. ? Plistophora sp. 
( Figs. 5-6 ) 

Host: Cambarellus puer Hobbs, 1945 

Location; Body musculature 

Locality: Near Covington, Louisiana 

Discussion: Sogandares (1962a) reported 
this form from one C. puer. This species is 
characterized by 19 to 21 comma-shaped 
spores, about 6.0 to 9.0 microns long by 4 
microns wide, contained in the pansporo- 
blast membrane. I have not collected this 
species again. 


Platyhelminthes 
Trematoda, Digenea 
Allocreadudae 
3. Crepidostomum cornutum (Osborn, 
1903 ) Stafford, 1904 
( Fig. 7) 

Hosts: Cambarellus puer Hobbs, 1945; 
C. shufeldti (Faxon, 1881); Orconectes lan- 
cifer (Hagen, 1870); Procambarus clarkii 
(Girard, 1852); P. blandingi acutus (Gi- 
rard, 1852); P. penni Hobbs, 1951 

Location: Hepatopancreas, heart, pericar- 


Figures 1-6. Microsporidians. 1-3. Thelo- 
hania sp., developing pansporoblasts; 4. 
same, pansporoblast membrane surround- 
ing spores; 5A,B,C,D, ?Plistophora sp. 
variation in shape and size of spores; 
6. same, pansporoblast membrane surround- 
ing spores. [Courtesy Journal of Parasitol- 
ogy 48(3): 493] 


dial membranes and musculature of cephalo- 
thorax. 


Localities: C. puer, C. shufeldti, and O. 
lancifer from Gibson (Terrebonne Par.) and 
Maringouin (Iberville Par.); P. clarki from 
Gibson, Ama, Bonnet Carre Spillway (St. 
Charles Par.), Sarpy (St. Charles Par.), 
Amite River on U. S. Hwy. 190 (East Baton 
Rouge Par.), Maringouin, Bayou close to 
Rosedale on La. Hwy. 76 (West Baton 
Rouge Par.), 1.7 mi. N. Junction La. Hwy. 
20 on La. Hwy. 309 (Terrebonne Par) eoee 
blanding: acutus from Amite River on U. S. 
Hwy. 190; P. penni trom near Pineville 
(Rapides Par.); all Loiusiana localities. 


Discussion: C. cornutum is without doubt 
one of the most common and widespread 
trematodes found encysted in Louisiana cray- 
fishes. Hopkins (1934) reported this spe- 
cies from crayfishes (listed as Cambarus sp. 
from Baton Rouge, Amphiuma means Cu- 
vier, “catfish,” and Ictalurus melas (Rafines- 
que) (—Ameimrus melas) in Louisiana. 
Stafford (1931) reported this species from 
Cambarus spp. in the neighboring state of 
Mississippi. The crayfishes reported by Hop- 
kins (1931) and Stafford (1931) cannot be 
identified because at that time most North 
American crayfishes were assigned to the 
genus Cambarus. 

Hopkins (1934) and Ameel (1937) both 
observed that encysted metacercariae of C. 
cornutum produced eggs. I observed such 
progenesis frequently in my specimen of 
C. cornutum trom Louisiana. It is really not 
known if these eggs are the result of par- 
thenogenesis or self-matings, or if the re- 


No. 3 Crayfish 
sultant developmental stages are capable of 
continuing with their normal biological 
functions of reproduction. 

One first intermediate host of C. cornu- 
tum in Louisiana is a sphaeriid clam of 
the genus Muasculium. Naturally infected 
sphaeriids have been collected at Gibson and 
at a bayou near Rosedale at the junction of 
La. Hwys. 76 and 413. Cercariae from clams 
of both localities readily encysted on the sur- 
face of the heart and hepatopancreas of 
laboratory reared P. clarkit and C. shufeldtz, 
lightly encysted matacercariae being found 
as early as 16 hours postexposure. 


Natural definitive hosts of C. cornutum 
found in this study were Amza calva Linn. 
and Lepomis macrochirus (Rafinesque). 
Other hosts in Louisiana have been cited 
above. 


Gorgodertdae 
4. Gorgodera amplicava Looss, 1899 
( Figs. 8-10) 
Hosts: Orconectes palmeri  creolanus 


(Creaser, 1933), Procambarus clarku (Gi- 
rard, 1852) 


Location: On lower quadrant of stomach 
wall, usually at level of gastric mill 


Localities: O. palmert creolanus from 
stream drainage into Bayou Sarah, about 1 
mile S. Mississippi State Line (West Felici- 
ana Par.); P. clark from Ama, Bonnet Carre 
Spillway, Sarpy, Maringouin, Edgard (La- 
fourche Par.), Buras (Plaquemines Par.), 
Pierre Pass (Assumption Par.), Venice 
(Plaquemines Par.), and 1.7 mi. N. Jct. La. 
Hwy. 20 on La. Hwy. 309. 

Discussion: Krull (1935) described the 
life cycle of this species. The partial life- 
cycle of G. amplicava has been experiment- 
ally established in this laboratory in young 
Rana clamitans Latreille and adult Amphrt- 
uma means Cuvier. Rana catesbeiana Shaw 
is one definitive natural host of G. ampli- 
cava in Louisiana, and has been shown by 
Penn (1950) to feed on crayfishes. Hyla 
cimerea (Schneider) and Chaenobryttus gu- 
losus (Cuv. & Val.) were refractory to in- 
fection. Judging from the site of encyst- 
ment, I suspect that crayfishes become in- 
fected by ingesting the cercariae. Almost all 
crayfishes collected in Sarpy, an oil field near 
Norco, Louisiana, were infected with G. 
amplicava. The species has been previously 
reported from crayfishes by Krull (1936). 


Parasites 81 


Microphallidae 
5. Microphallus opacus (Ward, 1894) 
Ward, 1901 
( Figs. 11-13) 
Host: Cambarellus puer Hobbs, 1945 and 
Procambarus clarkiit (Girard, 1852) 
Location: Hepatopancreas 


Locality: Bayou close to Rosedale on La. 
Hwy. 76. 


Discussion: M. opacus was the most com- 
mon metacercaria in P. clarkii at the Rose- 
dale locality, being found in about 98% of 
those examined. Ammnicola, probably integra, 
from the same locality released three differ- 
ent types of microphallid cercariae, prob- 
ably corresponding with the 3 microphallid 
tremadoes encysted in crayfishes from the 
same bayou. 

Encysted specimens of M. opacus were in- 
jected under the cephalothorax of P. clark 
and C. per from uninfected localities, but 
these worms did not produce eggs, even after 
three weeks, though they did remain alive 
for this period of time. CF, white mice were 
fed cysts of M. opacus and gravid specimens 
were recovered after 24 hours. The reser- 
voirs for the adults of M. opacus in the Rose- 
dale locality are unknown, though the species 
will develop to maturity in a number of 
vertebrates (Rausch, 1947). 

In this laboratory M. opacus would pro- 
duce eggs in 0.85% NaCl-1:20,000 Strepto- 
mycin sulfate solution in 12 to 36 hours at 
30 C. Metacercariae were artificially ex- 
cysted by vigorously shaking and incubating 
the entire infected crayfish hepatopancreas 
in a pepsin-HCl solution (100 ml. 0.3% 
HCI and 40 ml. 0.5% pepsin N.F.) at 40 C 
for 30 minutes, then incubating the washed 
cysts (0.85% NaCl) in a trypsin solution 
(0.5% trypsin in 0.85% NaCl, adjusted to 
pH 7.8 with K2HPO,) held at 40 C for 
10-12 min. The excysted metacercariae were 
then washed in 30 C 0.85% NaCl-1:20,000 
Streptomycin sulfate solution and later in- 
cubated in the same but clean solution. 
Thousands of clean excysted metacercariae 
could be obtained by following the above 
method. 

Rausch (1947) observed that when meta- 
cercariae of M. opacus were left in crayfish 
hepatopancreas extract overnight at room 
temperatures they excysted, found partners 
and began to mate. Ward (1900) also ob- 
served worms from natural infections 1 


82 Tulane Studies in Zoology Vol. 12 


0.5 


WRIELIL REY, 


7 PER x 

KTP RS 
LH ¥ Sx > 
FERS 


PSR 


Figures 7-20. Digenetic Trematodes. 7. Crepidostomum cornutum, excysted metacercaria; 
8. Gorgodera amplicava, excysted metacercaria; 9. same, adult from experimental infec- 
tion of Amphiuma; 10. same, eggs; 11. Microphallus opacus; excysted metacercaria; 12. 
same, adult from experimental infection of CF, mouse; 13. same, dorsal view of termi- 
nal genitalia; 14. Microphallus progeneticus, adult from Cambarellus puer; 15. same, ter- 
minal genitalia; 16. same, egg containing miracidium; 17. Maritrema obstipwm, excysted 
metacercaria; 18. same, terminal genitalia; 19. Macroderoides typicus, excysted meta- 
cercaria; 20. Paragonimus kellicotti, excysted metacercaria. The projected scales have 
their values indicated in millimeters. All figures accompanied by a projected scale were 
drawn with the aid of a Leitz camera lucida for inclined microscopes. Those figures lack- 
ing a scale are sketches. 


No. 3 Crayfish 
copula. In several experiments in this labo- 
ratory, encysted metacercaries from  post- 
pepsin-HCl treatment were individually iso- 
lated and incubated in trypsin-saline solu- 
tion. The resulting excysted worms, which 
had not been able to mate with a partner, 
were individually isolated in 4 x 40 mm 
tubes containing NaCl-Streptomycin solution 
and kept at room temperature. Approxi- 
mately 11% of the single worms treated as 
indicated above produced eggs of unascer- 
tained viability. By following almost the 
same procedure in another experiment, 50 
pairs of excysted M. opacus metacercariae 
were placed in identical tubes (2 worms per 
tube) and solutions. Eighty-four percent of 
these worms produced eggs, the viability of 
which was not determined. Further experi- 
mentation on this aspect has not been con- 
tinued since a severe drought in 1963 deci- 
mated the snail and crayfish populations. At 
present it is not known if mating is always 
necessary for the production of viable eggs, 
nor is it known if temperature or possible 
increase in titer of materials released by the 
mated pairs was responsible for egg produc- 
tion. Ching (1963a), for example, has in- 
dicated that increased (30 to 40 C) temper- 
ature stimulated egg production in Leven- 
sentella charadriformis Young, 1949. In an- 
other experiment (Ching, 1964b), she did 
not observe egg production of another micro- 
phallid, Maritrema laricola Ching, 1963, 
when held at 30 to 40 C. The viability of 
the eggs of the former species was not 
tested. Experiments of this type are neces- 
sary tO answer Certain questions of interest 
to trematode specialists. For example: Are 
eggs from isolated worms a result of par- 
thenogenesis or self-fertilization? Are the 
developmental stages of eggs produced by 
“self-matings” viable throughout their life- 
cycles? If self-matings are possible, what is 
the statistical significance of such self- 
matings on the species population structure? 


6. Microphallus progeneticus 
Sogandares, 1962 
( Figs. 14-16) 

Host: Cambarellus puer Hobbs, 1945, 
Procambarus clarku (Girard, 1852) 

Location: Cephalothoracic cavity 

Locality: Gibson, Maringouin, Bayou close 
to Rosedale on La. Hwy. 76, Louisiana. 

Discussion: This species, first found by 
Dr. Joseph Fitzpatrick, then a graduate stu- 


Parasites 83 


dent and assistant in my laboratory, was 
described by Sogandares (1962b). It is 
unique in lacking a complete pharynx and 
may be gravid when unencysted and wander- 
ing over the organs of the cephalothorax of 
the affected hosts. Eggs im wtero contain 
actively moving miracidia. 

Live specimens of Microphallus progene- 
ticus were intubated per ora into several 
CF, laboratory mice, but none were recoy- 
ered upon necropsy after 24 hours. The 
worms presumably were passed or digested 
by the host mice. M. progeneticus, except 
for the lack of a pharynx, is close to M. 
opacus, and may represent a sibling species 
of the latter. However, M. opacus is encysted 
and M. progeneticus is free in the crayfish 
hosts. Even if M. opacus could excyst in a 
crayfish host under certain conditions, which 
seems unlikely, excysted specimens experi- 
mentally introduced into the hemocoels of 
crayfishes failed to mature in three weeks, 
(see under M. opacus), though maturation 
took place in CF, laboratory mice and 7m 
vitro, It seems unlikely that gene flow be- 
tween the two forms could occur even if 
both were ingested by a single vertebrate 
host. 


7. Maritrema obstipum (Van Cleave and 
Mueller, 1932) Mueller, 1934 


(Figs. 17-18) 


Host: Cambarellus shufeldti (Faxon, 
1881) and Procambarus clarku (Girard, 
1852) 


Location: Central shaft of gill filaments 
and hepatopancreas 


Locality: Bayou close to Rosedale on La. 
Hwy. 76, Louisiana 

Discussion: This species was first observed 
by me in the gill filaments of its hosts. 
Later, great numbers were easily recovered 
from the hepatopancreas of affected hosts 
with the excystment procedure described 
under Microphallus opacus. Etges (1953) 
studied the life-history of Maritrema ob- 
stipum and found it encysted in the isopod 
Asellus communis. His identification of 
Maritrema obstipum seems doubtful at pres- 
ent, and completion of the life-history of 
the forms from crayfishes may elucidate the 
identity of his species. The first intermedi- 
ate host reported by Etges (1953) was Am- 
nicola pilsbryt. One of the three microphal- 
lid cercariae from Ammnzicola, reported under 


84 Tulane Studies in Zoology 


Microphallus opacus, is probably the larva 
of this species. Stafford (1931) reported a 
Maritrema sp. from Cambarus in Mississippi. 


Plagiorchitdae 
8. Macroderotides typicus (Winfield, 1929 ) 
Van Cleave and Mueller, 1932 
(Figil9 ) 

Hosts: Procambarus blandingi acutus (Gi- 
rard, 1852) P. clark (Girard, 1952), and 
Orconectes lancifer (Hagen, 1870) 

Location: Cephalothoracic and antennal 
musculature 

Localties: P. blandingi acutus and P. 
clarku from Edgard, P. clarku from Bayou 
near junction of La. Hwys. 413 and 76 
(West Baton Rouge Par.), and O. lancifer 
from Gibson, Louisiana. 

Discussion: Macroderoides typicus also 
utilizes tadpoles as second intermediate hosts 
(McMullen, 1935). The cercaria emerges 
from Helisoma trivolvis lentum in Louisi- 
ana. Adults of M. typicus have been found 
in Amia calva Linn. from Louisiana. Ex- 
posure of various species of sunfishes to 
cysts of M. typicus produced negative results. 


9. Ochetosoma sp. 
Host: P. clarkui (Girard, 1852) 
Location: Abdominal musculature 


Locality: Bayou close to Rosedale on La. 
Hwy. 76, Louisiana 

Discussion: Adult hosts of Ochetosoma in 
Louisiana are usually snakes of the genera 
Natrix and Agkistrodon. Certain species of 
Louisiana Ochetosoma are known to utilize 
physid snails and tadpoles as intermediate 
hosts (Byrd, 1935). Physids, tadpoles, and 
watersnakes were present in the locality in 
which the crayfishes were found infected 
with Ochetosoma. Penn (1950) has indi- 
cated that certain watersnakes feed heavily 
on crayfishes. Ninety-seven of 100 cray- 
fishes from the locality were found infected 
with Ochetosoma. 


Troglotrematidae 
10. Paragonimus kellicotti Ward, 1908 
( Fig. 20) 
Hosts: Procambarus blandingi acutus (Gi- 
rard, 1852) and P. clarki (Girard, 1852) 


Location: Heart and surrounding mem- 
branes 


Voleil2 


Locality: Amite River on U. S. Hwy. 190 

Discussion: My colleague, Dr. E. A. 
Malek, and I first collected this species in 
crayfishes. Experimental infections have 
been established in his and my laboratories, 
and a separate paper describing our results 
is in preparation. 


SUMMARY 


Parasites found in Louisiana crayfishes 
during this study are listed in Table 1. All 
localities visited for collection of crayfishes 
are indicated in Figure 21. Localities from 
which infected crayfishes were taken are in- 
dicated, under the specific parasite being 
considered, in the text. Where possible, 
local, experimental, and natural intermediate 
and definitive hosts of parasites discussed are 
cited in the text. 

The parasites found inhabiting crayfishes 
in Louisiana are represented by two micro- 
sporidians of the Nosematidae, and 8 dige- 


Se | 


Map showing collecting locali- 


Figure 21. 
ties in Louisiana. Areas visited are indi- 
cated by dark circles. 


netic trematodes by one species of Allo- 
creadiidae, one species of Gorgoderidae, 
three species of Microphallidae, two species 
of Plagiorchiidae, and one species of Tro- 
glotrematidae. 

The presence of Paragonimus kellicotti, 
the North American mammalian lung fluke, 
is of particular interest since the specific 
hosts in which this parasite was found are 
utilized as food by humans in Louisiana. 


Host-PARASITE INDEX 


Cambarellus puer 
Crepidostomum cornutum 
Microphallus opacus 
Microphallus progeneticus 
?Plistophora sp. 

Cambarellus shufeldti 
Crepidostamum cornutum 
Maritrema obstipum 
Thelohania sp. 

Orconectes clypeatus (Hay, 1899) 
Negative 

Orconectes lancifer 
Crepidostomum cornutum 
Macroderoides typicus 

Orconectes palmeri creolanus 
Gorgodera ampuicava 

Procambarus clarkii 
Crepidostomum cornutum 
Gorgodera amplicava 
Macroderoides typicus 
Maritrema_ obstipum 
Microphallus opacus 
Microphallus progeneticus 
Ochetosoma sp. 
Paragonimus kellicotti 

Procambarus blandingi acutus 
Crepidostomum cornutum 
Macroderoides typicus 
Paragonimus kellicotti 

Procambarus penni 
Crepidostomum cornutum 

Procambarus vioscai (Penn, 1946) 
Negative 


4 


LITERATURE CITED 


AMEEL, DONALD J. 1937. The life history of 
Crepidostomum cornutum (Osborn). J. 
Parasitol. 23: 218-220. 

Byrp, ELON E. 1935. Life history studies of 
Reniferinae (Trematoda, Digenea) para- 
sitic in Reptilia of the New Orleans area. 
Trans. Am. Microscop. Soc. 54: 196-225. 


CHING, HILDA LEI 1963a. The life cycle and 
bionomics of Levenseniella charadrifor- 
mis Young, 1949 (Trematoda: Microphal- 
lidae). Canad. J. Zool. 41: 889-899. 

1963b. The description 
and life cycle of Maritrema laricola sp. n. 
(Trematoda: Microphallidae) Canad. J. 
Zool. 41: 881-888. 

ETGES, FRANK J. 1953. Studies on the life 
histories of Maritrema obstipum (Van 
Cleave and Mueller, 1932) and Leven- 
seniella amnicolae n. sp. (Trematoda: 


Crayfish Parasites 85 


Microphallidae). 
662. 


HopPkKINS, SEWELL HEPBURN 1934. The pap- 
illose Allocreadiidae. JIl. Biol. Monogr. 
18: 45-124. 

KRULL, WENDELL H. 1935. Studies on the 
life history of a frog bladder fluke, Gor- 
godera amplicava Looss, 1899. Pap. Mich. 
Acad. Arts & Letters 20:697-710. 

ae . 1936. Additional second 
intermediate hosts for Gorgodera ampli- 
cava Looss, 1899. Proc. Helm. Soc. Wash. 

3 OSs 


McMULLEN, DONALD B. 1935. The life his- 
tory and classification of two allocrea- 
diid like plagiorchids from fish, Macro- 
deroides typicus (Winfield) and Allo- 
glossidium corti (Lamont). J. Parasitol. 
21: 369-380. 

PENN, GEORGE HENRY 1950. Utilization of 
crawfishes by cold-blooded vertebrates in 
the Eastern United States. Am. Midl. 
Nat. 44: 643-658. 


J. Parasitol. 39: 643- 


summary of their distribution within the 
state (Decapoda: Astacidae). Tulane 
Stud. Zool. 7: 3-20. 


RAUSCH, ROBERT 1947. Some observations 
on the host relationships of Microphallus 
opacus (Ward, 1894). Trans. Am. Micro- 
scop. Soc. 66: 59-63. 

SOGANDARES-BERNAL, FRANKLIN 1962a. Pre- 
sumable microsporidiosis in the dwarf 
crayfishes Cambarellus puer Hobbs and 
C. shufeldti (Faxon) in Louisiana. J. 
Parasitol. 48: 4938. 
ee ee ees 1962b. Microphallus pro- 
geneticus, a new apharyngeate progenet- 
ic trematode (Microphallidae) from the 
dwarf crayfish, Cambarellus puer, in 
Louisiana. Tulane Stud. Zool. 9: 319-322. 


SPRAGUE, VICTOR 1950. Thelohania cambari 
n. sp., a microsporidian parasite of North 
American crayfish. J. Parasitol. 36 (Sec 
Ai AG: 

STAFFORD, E. W. 1931. Platyhelmia insects 
and crustacea. J. Parasitol. 18:1381. 

VAN CLEAVE, HARLEY J. 1953. Acanthoce- 
phala of North American Mammals. /Il. 
Biol. Monogr. 23: 1-179. 

WarbD, HENRY B. 1900. Notes on the para- 
sites of the lake fish III. On the struc- 
ture of the copulatory organs in Micro- 
phallus nov. gen. Trans. Am. Microscop. 
Soc. 22: 175-187, 5 figs. 


June 23, 1965 


A NEW SUBSPECIES OF THE CRAWFISH ORCONECTES 
LEPTOGONOPODUS FROM THE OUACHITA RIVER 
DRAINAGE IN ARKANSAS 


J. F, PITZPATRICK,. JR:, 


Department of Biology, 
University of Virginia, 
Charlottesville? 


ABSTRACT 


A new subspecies of the crawfish 
Orconectes leptogonopodus Hobbs, O. l. 
acares, is described from the Ouachita 
River drainage in Arkansas. The new 
race is distinguished from the typical 
subspecies by shorter terminal elements 
of the first pleopod, a shorter pleopod, 
and other minor differences. Orconec- 
tes leptogonopodus leptogonopodus is 
recorded from Oklahoma. 


An excellent series of Orconectes lepto- 
gonopodus Hobbs (1948) was found among 
Tulane University lots of Ozark-Ouachita 
crawfishes sent to me for identification by 
Dr. George H. Penn shortly before his death. 
About the same time Dr. Horton H. Hobbs, 
Jr., of the United States National Museum 
sent an “interesting” series of the species 
collected by Dr. A. P. Blair from the Caddo 
River drainage. Examination of this large 
series revealed that Ouachita River popula- 
tions of O. leptogonopodus are morphologic- 
ally distinct from the topotypic population of 
O. leptogonopodus and from other popula- 
tions located in tributaries of the Red River. 
Accordingly, the Ouachita populations are 
recognized as subspecifically different from 
the Red River populations of O. leptogo- 
nopodus and a new subspecies is described. 


In addition to the persons mentioned 
above, the writer is indebted to Dr. Alfred 
E. Smalley of Tulane University who has 


1 Present Address: Department of Zoolo- 
gy, Mississippi State University, State Col- 
lege, Mississippi. 


permitted the selection of type material to 
be distributed as noted below. 


The name of this new subspecies is taken 
from the Greek, acares, short; it is so named 
because a prominent characteristic is the 
short, in comparison with /. leptogonopodus, 
terminal elements of the first pleopod. 


ORCONECTES LEPTOGONOPODUS 
ACARES, subsp. nov. 
Synonymy. 
Orconectes leptogonopodus Williams, 1954 
(in partim). 


Diagnosis; Pigmented; eyes normal. Ros- 
trum with marginal tubercles or spines, 
median carina present, margins subparallel 
or slightly converging cephalad, not thick- 
ened; length of areola 29.1 to 33.7 (mean 
31.8) per cent of total length of carapace, 
5.5 to 7.0 times longer than broad, three to 
five punctations in narrowest part. Post- 
orbital ridges strong, terminating cephalad 
in strong, divergent, corneous spines or tu- 
bercles; sides of carapace lacking lateral 
spines. First pleopod of first form male 
reaching caudal margin of coxopodite of 
first pereiopod with abdomen flexed; cen- 
tral projection with strong cephalic shoulder 
near base; central projection straight, longer 
than mesial process [ratio of central pro- 
jection length to mesial process length 1.25 
to 1.54 (mean 1.34)}, slender, with tip 
curving caudodistally; mesial process straight, 
setiform, slender, delicate; tips of first pleo- 
pod divergent (Figs. A, E). Annulus ven- 


EDITORIAL COMMITTEE FOR THIS PAPER: 


HorTON H. Hoss, JR., Senior Scientist, Department of Zoology, United States Na- 
tional Museum, Washington, D. C. 


ALFRED E. SMALLEY, Assistant Professor of Zoology, Tulane University, New Or- 


leans, Louisiana 


AUSTIN B. WILLIAMS, Professor of Zoology, University of North Carolina Institute 
for Fisheries Research, Morehead City, North Carolina 


87 


88 Tulane Studies in Zoology Volew2 


Figures A-J. Orconectes leptogonopodus acares. 

Legend. A. Mesial view of first pleopod of holotype; B. Mesial view of first pleopod 
of morphotype; C. Dorsal view of carapace of holotype; D. Lateral view of first pleopod 
of morphotype; E. Lateral view of first pleopod of holotype; F. Annulus ventralis of allo- 
type; G. Right chela of holotype, upper view; H. Epistoma of holotype; I. Antennal 
scale of holotype; J. Basipodite and ischiopodite of third pereiopod showing hook. (Me- 
sial process of holotype slightly warped in preservation; in life, it is less divergent and 
is straight.) 


No. 3 


tralis immovable, subrhomboid in outline, 
with prominent tongue-like caudal projec- 
tion, deep transverse trough in anterior half; 
sinus originating in trough, winding sinu- 
ously either sinistrally or dextrally, disappear- 
ing in caudal margin (Fig. F). 

Holotypic male, Form I; Body subcylin- 
drical, slightly depressed. Abdomen nar- 
rower than cephalothorax (8.5, 8.7 mm in 
widest parts, respectively). Width of cara- 
pace greater than depth in region of caudo- 
dorsal margin of cervical groove (8.7, 6.9 
mm ). 

Areola moderately broad (6.8 times longer 
than wide) with two or three punctations 
across narrowest part. Cephalic section of 
carapace about 1.9 times as long as areola. 
Length of areola 34.3 per cent of entire 
length of carapace. Dorsal features of cara- 
pace illustrated in Figure C. 

Rostrum with slightly converging margins; 
margins not distinctly thickened, but ter- 
minating cephalically in strong spines; upper 
surface deeply concave, bearing setiferous 
punctations, and with a moderately devel- 
oped median carina. Acumen short, broad; 
extending to distal end of peduncle of anten- 
nule; tip not upturned. Subrostral ridges 
evident in dorsal aspect for a short distance 
at bases. 

Postorbital ridges strong, grooved dorso- 
laterally, projecting cephalad in strong di- 
vergent spines. Suborbital angle acute. 
Branchiostegal spines acute. Carapace with 
a weakly developed tubercle on each lateral 
surface at level of branchiocervical groove. 
Entire carapace studded with  setiferous 
punctations except extreme cephalolateral 
ventral portions which bear setiferous granu- 
lations. 

Abdomen shorter than carapace (17.2, 
17.8 mm). Cephalic section of telson with 
two spines in each caudolateral corner. 

Epistome (Fig. H) subcircular in outline 
with cephalomedian tubercle. 

Antennules of usual form with prominent 
spine on ventral surface of basal segment. 
Antennae broken, but appear to have ex- 
tended to posterior region of abdomen. An- 
tennal scale (Fig. 1) about 2.2 times longer 
than broad, mesial margin of lamellar por- 
tion evenly rounded, widest distal to mid- 
length. 

Chela (Fig. G) depressed, palm inflated; 
all surfaces bearing setiferous punctations. 
Tubercle present on lower surface of palm 


New Crawfish 89 


at base of dactyl. Inner margin of palm 
with two irregular rows of tubercles, lower 
row of seven and upper row of six. Fingers 
with slight gap at base. Upper surface of 
immovable finger with broad, rounded, sub- 
median, longitudinal ridge flanked by seti- 
ferous punctations; another ridge along 
proximal three-fourths of finger immedi- 
ately mesial to aforementioned ridge. Outer 
margin of immovable finger with well- 
defined keel extending proximally two- 
thirds length of palm; opposable margin of 
finger with row of two small, one large, and 
three small tubercles (proximal to distal ) 
etxending along basal two-thirds and crowd- 
ed minute denticles along distal one-third; 
submedian longitudinal ridge on lower sur- 
face of finger. Dactyl similar to immovable 
finger above and below; mesial margin with 
double row of tubercles along proximal one- 
third, lower row of three but upper row 
with only one well-defined tubercle; oppos- 
able margin with five small tubercles along 
basal two-thirds and crowded minute denti- 
cles in distal one-third. 

Carpus of cheliped longer than broad and 
with broad shallow longitudinal furrow 
above; setiferous punctations over entire sur- 
face and few small tubercles on upper sur- 
face mesial to furrow; mesial surface with 
prominent tubercle on upper proximal one- 
third, strong acute spine on lower middle 
one-third, and tubercle on upper mesiodistal 
margin: lower submedian distal margin and 
lower laterodistal margin each with strong 
spine. Upper and lower surfaces of merus 
with scattered setiferous punctations; lateral 
surfaces generally smooth; three spines in 
line on upper distal surface; lower mesial 
surface with row of nine tubercles increas- 
ing in size distally, terminating in strong 
acute distal spine; single acute distal spine 
on lower laterodistal margin and row of one 
spine and nine tubercles proximal to distal 
spine. Lower surface of ischiopodite with 
small rounded tubercle. Hooks on ischiopo- 
dites of third pereiopods only (Fig. J); 
hooks simple. 

First pleopod extending cephalad to caudal 
margin of coxa of first pereiopod with ab- 
domen flexed. Tip terminating in two dis- 
tinct parts, both slender and setiform; rami 
separated for considerable distance from tips 
and moderately divergent (Figs. A, E). Cen- 
tral projection corneous, straight, but with 
tip curved caudodistally. Mesial process not 


90 Tulane Studies in Zoology 


extending so far distad as central projection, 
non-corneous, and quite delicate. (Delicate 
nature of mesial process results in preserva- 
tion artifacts; so noted in figure of holo- 
type.) Pleopods symmetrical (sensu Hobbs, 
1962). 

Morphotypic male, Form Il: Differs from 
holotype in following respects: lateral tuber- 
cles of cephalothorax lacking. Carpus of 
cheliped with upper mesiodistal spine. Palm 
less inflated and proportionately smaller than 
holotype. Hooks on ischipodites of third 
pereiopods much reduced. Both elements of 
pleopod (Figs. B, D) non-corneous, blunter 
and in close apposition along basal three- 
fourths. 

Allotypic female: Differs from holotype 
in following respects: palm proportionately 
smaller and less inflated than holotype. First 
pleopod biramous and weakly developed. 

Annulus ventralis immovable, subrhom- 
boid in outline with prominent tongue-like 
projection of caudal margin, fused ceph- 
alically with sternum but with two promi- 
nent lateral tubercles raised (ventrally) in 
cephalic half. Deep transverse trough in 
cephalic half, with aforementioned tubercles 
overhanging cephalolateral portions. Sinus 
originating in trough, curving gently caudo- 
sinistrally, then caudally following sinuous 
path to caudal margin of annulus (Fig. F). 

Type locality: Stream tributary to Ouach- 
ita River, 6 mi. northwest of Mt. Ida, Mont- 
gomery County, Arkansas. 

Disposition of the types: The holotypic 
male, Form I; the allotypic female; and the 
morphotypic male, Form HI, are in the col- 
lections of the United States National Mu- 
seum (mos. 115517, 115518, and 115519, 
respectively ). Paratypes are deposited in the 


Vol. 12 


U. S. National Museum (nos. 114821 and 
114822), the Museum of Comparative Zo- 
ology, Harvard University (no. 12637), Tu- 
lane University (parts of Lots 2500, 2956, 
3081, 3082, 3083, 3150, 3346, 3364, 3443, 
3444, 3450, and 3451), and in personal col- 
lections of the author. The paratypic series 
is a total of 218 specimens representing both 
forms of the male, females, and juveniles of 
both sexes. The specimens at MCZ and in 
collections of the author are among speci- 
mens designated topoparatypes. 

Range: This subspecies is confined to 
tributaries of the Ouachita River and has 
been collected from the following counties 
in Arkansas: Garland, Hot Springs, Mont- 
gomery, Perry, Pike, Polk, and Saline. 

Variations: There are relatively few vari- 
ations in the specimens examined. In some 
there are less pronounced cephalomedian 
projections of the epistome, and in a few 
specimens the projection is lacking. In some 
specimens the terminal elements of the pleo- 
pod are longer than usual, resulting in a 
greater central projection: mesial process 
ratio. Lateral tubercles of the carapace are 
lacking in many specimens. 

Relationships: Orconectes leptogonopodus 
acares has its closest affinities with O. /. 
leptogonopodus Hobbs. Although there are 
no evidences of intergrade populations 
among the specimens examined, Jones Creek 
and Caddo River specimens show definite 
tendencies toward typical leptogonopodus 
morphology, and specimens of O. leptogo- 
nopodus leptogonopodus from McCurtain 
County, Oklahoma, show definite tendencies 
toward morphological features of O. lepto- 
gonopodus acares. O. |. leptogonopodus 
appears to be restricted to tributaries of the 


TABLE I. 
Measurements of type specimens of Orconectes leptogonopodus acares. 
(All measurements in mm) 


Holotype 

Carapace— height 6.9 
width 8.7 
length 17.8 
Areola— length 6.1 
width 0.9 
Rostrum— length 4.9 
width 2.8 

Chela— length of inner 
margin of palm 5.0 
width of palm 6.5 

length of outer 
margin of palm 14.1 
length of dactyl 8.5 


Allotype Morphotype 
10.4 1.5 
8.7 8.7 
25.3 18.0 
8.6 5.9 
Wee ileal 
5.9 5.0 
3.4 3.0 
7.0 4.8 
8.5 6.3 
19.1 12°59 
10.7 Coll 


No. 3 


Red River in Arkansas and eastern Okla- 
homa, while O. /. acares, is confined to 
tributaries of the Ouachita River, from the 
Caddo River upstream. O. /. acares may 
be distingiushed from O. |. leptogonopodus 
by a shorter pleopod, a shorter central pro- 
jection, and a smaller central projection: 
mesial process ratio (mean value for 
acares: 1.34; for /eptogonopodus: 1.43). 
In O. /. acares there is a greater tendency 
toward development of a cephalomedian 
projection of the epistome, and there are 
slight differences between the two subspecies 
in outline of the cephalic margin of the 
annuli ventrales. 

Remarks: Orconectes leptogonopodus has 
never been reported from outside the state 


of Arkansas, but two collections in the 
USNM are from Oklahoma: (1) 8 Oct. 


New Crawfish 91 


1955, McCurtain Co. (?), Eagle Creek, trib. 
to Mountain Fork Riv., nw of Smithville, 
coll. A. P. Blair (2?) (Hobbs Collections ) ; 
and (2) 28 Nov. 1963, McCurtain Co., 
Broken Bow, 6 NNE, coll. A. P. Blair, and 
both of these contained specimens which I 
identified as O. 1. leptogonopodus. 


LITERATURE CITED 


Hopss, H. H. Jr., 1948. Two new crayfishes 
of the genus Orconectes from Arkansas 
with a key to the species of the Hylas 
Group. Amer. Midl. Nat. 39: 189-150. 


Pameedt s «B _., 1962. Notes on the af- 
finities of the members of the Blandingii 
Section of the crayfish genus Procam- 
barus. Tulane Stud. Zool. 9: 273-298. 


WiuurAMs, A. B. 1954. Speciation and dis- 
tribution of the crayfishes of the Ozark 
Plateaus and Ouachit: Provinces. Univ. 
Kansas Sci. Bull. 36: 808-918. 


June 23, 1965 


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Volume 12, Number 4 


TULANE STUDIES IN ZOOLOGY 


October 11, 1965 


ECOLOGICAL DISTRIBUTION AND ACTIVITY PERIODS OF BATS 
OF THE MOGOLLON MOUNTAINS AREA OF NEW MEXICO 
AND ADJACENT ARIZONA 


CLYDE JONES 
Department of Biology, Tulane University 
New Orleans, Loutstana 


ABSTRACT 


Data concerning ecology and distri- 
bution are presented and summarized 
for 19 species of bats from southwest- 
ern New Mexico and adjacent south- 
eastern Arizona. Time of capture and 
air temperature at time of capture are 
given for all species. Environmental 
factors that may influence activity and 
distribution of bats are discussed. 


INTRODUCTION 


Few observations have previously been 
published on bats in New Mexico, and in- 
formation on general ecology has often been 
incidental to distributional or taxonomic 
studies. Bailey (1931), while presenting 
geographic ranges of bats known from New 
Mexico, made some mention of ecology and 
natural history. More recently, limited eco- 
logical information has been contributed by 
Mumford (1957, 1964), Commissaris (1959), 
Findley (1960), Constantine (196la, b), 
Harris (1963), and others. Sheppard (1962) 
assembled natural history and ecological data 
for the species of bats occurring in Bernalillo 
Co., New Mexico. 


The purpose of this report is to furnish 
information concerning distribution and gen- 
eral ecology and to discuss briefly the factors 
that may influence activity and distribution 
of bats of the Mogollon Mountains area of 
southwestern New Mexico and adjacent 
southeastern Arizona. 


DESCRIPTION OF THE AREA 


Fenneman (1931) included the northern 
part of the study area (north of 33° N lat) 
in the Datil section of the Colorado Plateau 
physiographic province and the southern 
part (south of 33° N lat) in the Mexican 
Highland division of the Basin and Range 
province. The study area is composed of a 
portion of the Mogollon Rim and several 
semi-isolated and isolated smaller mountain 
ranges bordered on the north by the closed 
basin of the San Augustin Plains and on the 
east and south by the Rio Grande and Gila 
River drainages (Fig. 1). From the lowest 
elevation of 3,800 ft on the Gila River at 
the Arizona-New Mexico border the altitude 
rises to 10,788 ft in elevation at the highest 
point, Mogollon Peak. Precipitation in the 
area is variable, ranging from about 10 to 
16 inches annually (little or no weather data 
are available from montane areas), with the 
heaviest rainfall occurring in July and Au- 
gust (Hardy, 1941). 

The Mogollon Mountains area has biotic 
communities characteristic of the southern 
Rocky Mountains (Lowe, 1964). For the 
purposes of this study, three biotic com- 
munities are recognized. 

Xeric-shrub grassland —Present and wide- 
spread below 6,000 ft except for restricted 
stands of evergreen and deciduous vegeta- 
tion on north-facing slopes and canyon 


EDITORIAL COMMITTEE FOR THIS PAPER: 


ANDREW A. ARATA, Associate Professor of Zoology, Tulane University, New Orleans, 


Louisiana 


Dr. MARTIN EISENTRAUT, Museum Alexander Koenig, Bonn, West Germany 


PHitip H. KRUTZSCH, Professor and Head of Anatomy, College of Medicine, Uni- 


versity of Arizona, Tucson, Arizona 


94 Tulane Studies in Zoology 


floors. Conspicuous species of plants found 
in the xeric-shrub grassland are Muhlen- 
bergia wrightu, Bouteloua gracilis, Atriplex 
canescens, Chrysothamnus spp., Larrea tri- 
dentata, Prosopis juliflora, and P. pubescens 
with Populus spp., Tamarix gallica, and Ele- 
agnus angustifolia commonly riparian. 

Evergreen-deciduous woodland.—Present 
throughout the study area from below 5,000 
ft on north- facing slopes to above 7,000 ft 
on ridges and south-facing slopes. Some 
plants that make up the evergreen-deciduous 
woodland are Juniperus monosperma, J. sco- 
pulorum, J. deppeana, Pinus edulis, Quercus 
grisea, O. gambeli, and Cercocarpus brevi- 
florus. 

Evergreen forest—Widespread above 
7,000 ft, present in restricted stands at lower 
elevations and in heads of cool, mesic can- 
yons. Some common species of plants of 
the evergreen forest are Pinus ponderosa, 
P. flexilis, P. edulis, Picea engelmannit, P. 


APACHE CO. 


Volz 


pungens, Abies concolor, A. lastocarpa, A. 
lastocarpa var. arizonica, Pseudotsuga men- 
stesit, Quercus gambeliu, and Populus tremu- 
loides with Salix spp., Alnus tenutfolia, and 
Acer spp. often riparian. 


METHODS AND MATERIALS 


Bats were, for the most part, captured in 
mist nets stretched across water tanks, over 
ponds and streams, or over entrances to 
mines and caves. Nets were maintained 
ordinarily for 5 to 6 hrs per night. Attempts 
were often made to maintain nets all night, 
however, nets frequently were left standing 
unattended all night and were checked dur- 
ing the early nots hours. In addition to 
those netted, a few bats were shot. Most 
data presented, hee were gathered in 1960, 
but limited field studies were conducted 
from 1958 through 1963. 


Whenver possible, time of capture, air 
temperature at the time of capture, and sex 


CATRON 


co. 


Figure 1. Map of the study area showing biotic communities and collecting stations. Ev- 
ergreen forest is represented by lined areas, evergreen-deciduous woodland is represented 
by white areas, and xeric-shrub grassland is represented by stippled areas. The distribu- 
tion of collecting stations is a reflection of the presence of permanent water over which 
to sample bats. 


No. 4 


of each individual were recorded upon col- 
lection of the bat. Data on time of capture 
and air temperature at the time of capture 
were analyzed and compared by means of 
standard _ statistical methods; arithmetic 
mean, standard deviation, and standard error 
of the mean were computed. Because there 
were no significant differences between the 
two sexes in time of capture or air tem- 
perature at time of capture, data for males 
and females were combined. Weather con- 
ditions were noted in an attempt to deter- 
mine the role of such factors as wind, rain, 
and moonlight in relation to activity of the 
animals studied. 

In all, 1595 specimens were obtained from 
the study and were preserved in the Museum 
of Southwestern Biology at the University 


Bat Ecology 95 


of New Mexico either as standard museum 
study skins and skulls with carcasses pre- 
served in fluid or were preserved entire in 
fluid. 
RESULTS 

The Chiropteran fauna of each of the 
biotic communities is summarized in Table 
1. On the basis of the data presented herein, 
13 species of bats are considered to be high- 
land forms (greatest percentage of individ- 
uals collected were from localities in ever- 
green forest generally above 7,000 ft in 
elevation), and six species are regarded as 
lowland forms (greatest percentage of in- 
dividuals collected were taken at localities 
in xeric-shrub grassland and evergreen- 
deciduous woodland mostly below 7,000 ft 
in elevation). Myotis occultus is equally 


TABLE 1. 

Percentage of each species and percentage of all bats collected in each biotic community, 
as well as bats collected per station (number of bats collected in a community 
divided by the number of collecting stations in that community) 
in each biotic community. 


Percent of total number taken 
in xeric-shrub grassland 


Total number taken 


Myotis californicus 22, 
Myotis evotis 61 
Myotis keenii 42 
Myotis oceultus 66 45.5 
Myotis subulatus 35 13.5 
Myotis thysanodes 84 
Myotis velifer 3 33.4 
Myotis volans 226 
Myotis ywmanensis 137 89.6 
Lasionycteris noctivagans 105 
Pipistrellus hesperus 43 58.1 
Eptesicus fuscus Pat | 1.5 
Lasiurus borealis 4 
Lasiurus cinereus 191 252, 
Plecotus phyllotis oH 
Plecotus townsendii 39 8.0 
Euderma maculatum 7 
Antrozous pallidus 95 45.2 
Tadarida brasiliensis 126 32.8 
Tadarida molossa 1 
Total 1595 Mays 


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35.0 65.0 el .68 
100.0 3.05 
14.3 85.7 66 1.86 
54.5 2.0 1.80 
20.5 65.0 5333 .88 1-26 
At 95.3 44 4.31 
66.6 .06 Ape 
2.6 97.4 .66 11.00 
5.2 baz 3.46 $33 5 
25.8 74.2 3.00 4.10 
39.5 2.4 1.66 1.42 .05 
9.0 89.5 .26 Patty 12.40 
100.0 44 
41.3 56.5 26 Satu 5.86 
9.7 90.3 .30 1.47 
18.4 73.6 .20 hat 1.47 
100.0 .36 
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54.4 1278 Zale 75D 84 
100.0 05 
19.9 66.4 13.80 33.50 50.30 


96 


distributed in the xeric-shrub grassland and 
in evergreen forest, whereas Myotzs evotis is 
restricted to the evergreen-forest community. 
Myotis velifer, Lasiurus borealis, Euderma 
maculatum, and Tadarida molossa were taken 
on too few occasions to determine the true 
habitats of the species. Lastonycteris nocti- 
vagans and Lasiurus cinereus, considered 
here as highland species, were taken at lower 
elevations during April, May, and June, but 
were more abundant at higher elevations in 
July and August. Vaughan and Krutzsch 
(1954) suggest a similar distribution for 
L. cinereus in southern California. 


The seasonal distributions of each species 
of bats is summarized in Table 2. Four spe- 
cies (Myotis velifer, Lasturus borealis, Eu- 
derma maculatum, and Tadarida molossa) 
perhaps are represented by insufficient num- 
bers to give a valid indication of seasonal 
distributions of the species. Bats were most 
abundant in the study area during June and 
July (Table 2) and were least abundant 
during August. Females were more abundant 
than males in April and May, but males 
were slightly more abundant than females 
during the remainder of the season of study. 

The range of time, expressed in minutes 
after sunset, in which each species was active 
is presented in Fig. 2. Three species (Myoztzs 


Tulane Studies in Zoology 


Vol=12 


californicus, M. occultus, and Pipistrellus 
hesperus) were active mostly during the 
first 1 hr and 40 min after sundown. Mum- 
ford (1964) and Cockrum and Cross (1964) 
present similar data for P. hesperus. Other 
species (Myotis evotis, M. subulatus, M. 
velifer, M. yumanensis, Lasiurus cinereus, 
Plecotus townsendu, Euderma maculatum, 
Antrozous pallidus, and Tadarida brasilien- 
sis) seemingly have a later period of ac- 
tivity, mostly after the first 1 hr and 40 
min after sundown. The seven remaining 
species seem to be active during a period 
intermediate to the two aforementioned 
groups. The data indicate peaks in the ac- 
tivity of the animals during the first 2 hrs 
after sunset (Fig. 2). In only one case was 
predawn collecting successful. 


Air temperature at capture is given for each 
species in Fig. 3. For those species where 
ten or more individuals are represented, a 
few general trends are suggested: Plecotus 
phyllotis was taken in a narrow range of 
temperature from 9 to 17° C, whereas 
Lasionycteris noctivagans (minus 2 to 20° 
C), Lasiurus cinereus (O to 22° C), and 
Tadarida brasiliensis (7 to 27 °C ) were 
active through a wide range. A high tem- 
perature preference, mostly above 20° C, 
was shown by Myozis vel'fer, Lasiurus bore- 


TABLE 2. 
Numbers of bats of each species taken per night each month (number of bats collected 
each month divided by the number of nights bats were collected in each month). The 
total number of times bats were collected each month is given in parentheses 


with the name of each month. 


Total 


July Aug. 


April May June Sept. Oct. 

taken (9) (7) (36) (2) (ali2}) (9) (1) 
Myotis velifer 3 .08 
Tadarida molossa 1 .03 
Lasiurus borealis 4 aA .08 
Myotis occultus 66 1.08 .85 139 
Plecotus phyllotis 31 BPA, .36 .59 
Myotis californicus 22 29 .36 18 aPape 
Myotis subulatus 35 .66 .44 OU A) 
Myotis evotis 61 14 .36 1.18 41 I galal 
Myotis keenti 42 .44 .50 .28 a3) .44 
Pipistrellus hesperus 3 Seve -O7 .69 78) .308 
Antrozous pallidus 95 122 29 2.09 3212 cleat 
Myotis thysanodes 84 Le oll 1.16 alt AIUG .66 
Myotis volans 226 00 14 PA Alyy 3.25 1.08 Biola 
Myotis yuwmanensis 137 .44 14 .30 MOT a6; KOR 
Plecotus townsendii 39 alta Sy) 30 silat Al Ge 
Tadarida brasiliensis 126 .08 a9 1.55 26 1.25 2.66 
Lasiurus cinereus 191 .44 71.85 3.02 .70 BAP 1.00 
Lasionycteris noctivagans 105 1.00 1.42 2.03 -29 .08 33 1.00 
Eptesicus fuscus 277 44 aia 4.30 2.03 ag) 4.77 4.00 
Total 66 6.16 6.00 


1595 fic 


21.47 12.92 26.22 


No 4 


alis, and Euderma maculatum; however, 
these data represent less than ten observa- 
tions each, and thus may not be meaningful. 


DISCUSSION 

The data presented in Table 1 provide an 
indication of the habitat of the various spe- 
cies of bats found within the study area. 
Inasmuch as the number of times collections 
MYOTIS CALIFORNICUS (14) 
MYOTIS EVOTIS (43) 


MYOTIS KEENII (25) 


MYOTIS OCCULTUS (24) 
MYOTIS SUBULATUS (24) 
MYOTIS THYSANODES (22) 
MYOTIS VELIFER (3) 
MYOTIS VOLANS (183) 


MYOTIS YUMANENSIS (9) 


LASIONYCTERIS 
NOCTIVAGANS (85) 


PIPISTRELLUS HESPERUS (29) (er 


EPTESICUS FUSCUS (221) 

LASIURUS BOREALIS (2) 

LASIURUS CINEREUS (154) 
PLECOTUS PHYLLOTIS (24) 
PLECOTUS TOWNSENDII (12) 
EUDERMA MACULATUM (5) 
ANTROZOUS PALLIDUS (66) 


TADARIDA BRASILIENSIS (45) 


100 


Bat Ecolog) 07 


were made within each plant community 
and the number of localities from which 
collections were made varied, bats collected 
per station may be the least biased means of 
comparing habitats. 


The great abundance of bats in the early 
part of the collecting season is due to the 
presence of relatively large numbers of fe- 


RS ce cs ne 
meee 
_ com 


_ oe 
rela 


Pcs xi bo A ee ES 


200 300 


MINUTES AFTER SUNSET 


Figure 2. 


Range of time, expressed in minutes after sunset, in which each of 19 species 


of bats was active. The horizontal line represents the range, the central vertical line indi- 
cates the arithmetic mean, the shaded area represents plus or minus two standard errors 
of the mean, and the unshaded area encloses plus or minus one standard deviation. For 
each species, the total number of bats for which data are available is given in parentheses. 
Time of sunset was corrected for latitude after being taken from tables furnished by the 


United States Weather Bureau. 


98 Tulane Studies in Zoology 


males, whereas the numbers of bats present 
later in the season may be the result of 
premigratory or prehibernatory groupings of 
some species (Table 2). The abundance of 
certain species (Lasionycteris noctivagans 
and Lasiurus cinereus) early and again late 
in the collecting season is a reflection of 
movements of animals 


migratory these 
MYOTIS CALIFORNICUS (14) 
MYOTIS EVOTIS (46) 
MYOTIS KEENII (25) 
MYOTIS OCCULTUS (24) 
MYOTIS SUBULATUS (20) 
MYOTIS THYSANODES (22) 
MYOTIS VELIFER (3) 
MYOTIS VOLANS (154) 
MYOTIS YUMANENSIS (8) 
LASIONYCTERIS 
NOCTIVAGANS (81) 
PIPISTRELLUS HESPERUS (29) 
EPTESICUS FUSCUS (220) 
LASIURUS BOREALIS (2) 
LASIURUS CINEREUS (153) 
PLECOTUS PHYLLOTIS (23) 
PLECOTUS TOWNSENDII (12) 
EUDERMA MACULATUM (5) 
ANTROZOUS PALLIDUS (66) 


TADARIDA BRASILIENSIS (46) 


Figure 3. 


Volei2 


through the study area (Findley and Jones, 
1964). The small numbers of bats taken 
in the study area during August may have 
been caused by heavy rains during late July 
and August and resultant abundance of 
watering places. Observations during the 
rainy period indicated some decrease in num- 
bers of bats in areas where heavy concen- 


10 20 30 


TEMPERATURE IN DEGREES CG 


Range of air temperature in which each of 19 species of bats was active. The 


horizontal line represents the range, the central vertical line indicates the arithmetic 
mean, the shaded area represents plus or minus two standard errors of the mean, and the 
unshaded area encloses plus or minus one standard deviation. For each species, the total 
number of bats for which data are available is given in parentheses. 


No. 4 


trations were previously noted. Because of 
the increased availability of drinking water, 
bats probably were more widely dispersed 
during late July and August. Although 
water-hole samples of bats are considered 
herein as indicators of the entire community, 
it is realized that there is differential prob- 
ability in the capture of bats in mist nets 
(Cockrum and Cross, 1964). 

Bats are well known for marked periodi- 
cites in their normal habits (Griffin and 
Welsh, 1937). During the summer, bats of 
the species considered here probably spend 
the day in roosts and emerge after sundown 
to seek food and water. Depending perhaps 
on the abundance of food and on temper- 
ature, bats may return to the roosts after a 
time or may forage throughout the night. 
Gould (1961) reported that light intensity 
and rain are important factors that influ- 
enced the time of emergence of Tadarida 
femorosacca, and suggested that temperature 
and total solar radiation during the day did 
not affect the time of emergence. Baker 
(1961) noted a general trend in the emer- 
gence of Tadarida brasiliensis from late 
times of flight in May to early times of 
flight in October. Analysis of the data pre- 
sented in Figs. 2 and 3 indicated that there 
is some correlation between air temperature 
and time capture of some species of bats. 
Members of one species, Myotis evotis, were 
active during a low range of temperature 
and were captured at time somewhat later 
than other related species, but for another 
species, Pzpistrellus hesperus, the converse 
was true. Some bats (Myotis yumanensis 
and Pzpistrellus hesperus) that were active 
during warm temperatures were taken either 
for a short period of time early in the eve- 
ming or were active for longer periods of 
time only when warm temperatures pre- 
vailed. Drinking and feeding activity of bats 
apparently is correlated with the air tem- 
perature. Any relationship of temperature 
to the time of emergence of the species con- 
sidered here is obscured by the nature of the 
data. The observations reported here do not 
permit speculation as to the distance bats 
may travel from roosts to watering areas 
and no evidence is available as to how soon 
after leaving the diurnal roosts bats approach 
water surfaces. Some bats may fly directly 
from roosts to water (Hayward and Davis, 
1964), but other bats may follow an indirect 
route to water. 


Bat Ecology 99 


In general, the ranges of temperatures in 
which the species of bats were active coin- 
cide with distribution and habitat of the 
animals. The species (Plecotus phyllotis) 
that was active in a narrow range of tem- 
perature (9 to 17° C) is more limited in 
geographic distribution than those species 
(Lastonycteris noctivagans and Lasiurus 
cereus) that were active through a wide 
range of temperature (minus 2 to 20° C 
and 0 to 22° C). Myotis evotis, for which 
a low temperature preference was indicated 
(6 to 18° C), was not taken at low eleva- 
tions (below 7,000 ft) and Myozis velifer, 
M. yumanensis, and Prpistrellus hesperus, 
for which high temperature preferences were 
indicated. 62h to. 23° G 19 to 41° © and 
14 to 29° C), were rarely taken at high ele- 
vations (above 7,000 ft). Preference for 
high temperatures suggest that some of the 
so-called lowland species of bats (Myotis 
velifer, M. ywmanensis, and Pipistrellus hes- 
perus) possibly are incapable of inhabiting 
highland areas, at least within the latitudes 
encompassed in this study. The converse 
may be true for the so-called highland form 
(Myotis evotis). On the other hand, the data 
indicate that some species (Lasionycteris 
noctivagans and Lasiurus cinereus), for 
which low temperature preferences are sug- 
gested, inhabit regions of high or low ele- 
vation and north or south latitudes con- 
cordant with season. 

Activity of the bats included here, seem- 
ingly, was not affected by weather condi- 
tions, although Sheppard (1962) and 
Gould (1961) suggest that factors such as 
wind, humidity, cloud cover, and moonlight 
may influence the activity of bats. Wind and 
moisture seemed to influence only the num- 
ber of bats caught, not the number observed. 
On many occasions bats were seen drinking, 
flying about, and striking a net blown so 
tightly by the wind that no animals became 
entangled in the mesh. Several times bats 
were captured when foggy conditions pre- 
vailed and on a few occasions were taken 
during heavy showers. 

Distribution of certain tree-roosting bat 
species is influenced by vegetation. For the 
other species of bats reported herein, few 
data are available to indicate any direct cor- 
relation between bat distribution and spe- 
cific vegetation. Distribution of bats per- 
haps is influenced by the availability of suit- 
able roosting sites, proper amounts of food 


100 


materials, and adequate water surfaces for 
drinking. Temperatures must be considered 
an important factor influencing certain ac- 
tivities and, perhaps, the distribution of bats. 


SUMMARY 


Of the 19 species of bats occurring in the 
study area, 13 species were collected in high- 
land areas (above 7,000 ft), six species were 
taken in lowland regions (below 7,000 ft), 
and one species was distributed equally in 
lowland and in highland areas. Only one 
species was restricted in distribution to a 
particular community. 

Bats were most abundant in the study 
area during June and July. Females out- 
numbered males in the spring, but males 
were slightly more abundant than females 
during the summer and early fall. 

Three species of bats were active during 
the first 1 hr and 40 min after sundown, 
nine species were active during a later 
period of time, and seven species were active 
during a period intermediate to the afore- 
mentioned groups. 

Some species were taken in a narrow 
range of temperature (8° C); other species 
were taken in a wide range (20° C). Pref- 
erences for high temperatures were indicated 
by three species and preferences for low tem- 
peratures were detected for several species. 
The ranges of temperatures in which bats 
were active correlate with distribution and 
habitat of the animals. 


ACKNOWLEDGMENTS 


James S. Findley, Eugene Fleharty, David 
Niles, John Wright, Eugene Schroeder, 
Arthur Harris, and Dick Forbes either helped 
in the field or contributed specimens from 
the study area. I received financial assistance 
from the National Science Foundation dur- 
ing 2 months in each of the summers of 
1958 and 1959, and for 3 months during 
the summer of 1960. 


LITERATURE CITED 


BAILEY, V. 1981. Mammals of New Mexico. 
N. Am. Fauna 53:1-412. 


BAKER, J. 1961. What about bats? Carls- 
bad Caverns Nat. Hist. Assoc. 55 p. 


Tulane Studies in Zoology 


Vol. 12 


CockruM, E. L., and S. Cross. 1964. Time 
of bat activity over water holes. J. Mam- 
mal, 45:635-636. 


CoMMIssarIs, L. 1959. Notes on the Yuma 
Myotis in New Mexico. J. Mammal. 40: 
441-442. 

CONSTANTINE, D. 1961a. 
and notes on western bats. J. 
42:404-405. 

CONSTANTINE, D. 1961b. Spotted bat and 
big free-tailed bat in northern New Mexi- 
co. Southwestern Nat. 6:92-97. 

FENNEMAN, N. 1931. Physiography of wes- 
tern United States. McGraw-Hill Book 
Company, Inc., New York. 714 p. 


Locality records 
Mammal. 


FINDLEY, J. 1960. Identity of the long-eared 
Myotis of the Southwest and Mexico. J. 
Mammal. 41:16-19. 


FINDLEY, J., and C. JONES. 1964. Seasonal 
distribution of the hoary bat. J. Mammal 
45 :461-470. 


GOULD, P. 1961. Emergence time of Tada- 
rida in relation to light intensity. J. 
Mammal. 42:405-407. 


GRIFFIN, D., and J. WELSH. 1937. Activity 
rhythms in bats under constant external 
conditions. J. Mammal. 18:337-342. 


Harpy, E. 1941. Climate of New Mexico. 
In Climate and Man, Yearbook of Agri- 
culture: 1011-1024. U. S. Dept. of Agri- 
culture, Washington, D. C. 


Harris, A. 1963. Ecological distribution of 
some vertebrates in the San Juan Basin, 
New Mexico. Musewm of New Mexico 
Press, Papers in Anthropol. 8:1-63. 


HAYWARD, B., and R. DaAvis. 1964. Flight 
speeds in western bats. J. Mammal. 45: 
236-242. 


LowE, C. 1964. Arizona landscapes and hab- 
itats. In Vertebrates of Arizona. Univ. 
Arizona Press, Tucson. 132 p. 


Mumrorp, R. 1957. Myotis occultus and My- 
otis yumanensis breeding in New Mexico. 
J. Mammal. 38:260. 


Mumrorp, R. 1964. June bat records from 
Guadalupe Canyon, New Mexico. Souwth- 
western Nat. 9:43-45. 

SHEPPARD, F. 1962. An annotated checklist 
of the bats of Bernalillo County, New 
Mexico. M.S. Thesis. Univ. New Mevxico. 
101 p. 


VAUGHAN, T., and P. KruTzscuH. 1954. Sea- 
sonal distribution of the hoary bat in 
southern California. J. Mammal. 35:431- 
432. 


ETHEOSTOMA (OLIGOCEPHALUS) NUCHALE, A NEW DARTER 
FROM A LIMESTONE SPRING IN ALABAMA 


WILLIAM MIKE HOWELL 
and 
RICHARD DALE CALDWELL 


Department of Biology, University of Alabama 
University, Alabama 


ABSTRACT 


Etheostoma (Oligocephalus) nuchale 
is described from 71 specimens collected 
from a limestone spring in the Black 
Warrior River system near Bessemer, 
Jefferson County, Alabama. FH. nuchale 
is known only from Glen Spring, the 
type locality, which is located above the 
Fall Line. It is compared to its nearest 
known relative, H#. swaini (Jordan), 
from which it is geographically iso- 
lated. E. swaini does not normally cross 
the Fall Line, and is a wide-ranging 
species found along the Gulf Coastal 
Plain from the Ochlockonee River in 
Florida to the Amite River system of 
southeastern Louisiana and _ southern 
Mississippi. The species differ in de- 
tails of body proportions, squamation, 
pigmentation, development of lateral 
line and cephalic sensory canals, cer- 
tain fin-ray counts and habits. 


On 21 March 1964, Dr. Ronald A. Bran- 
don and Ron Altig collected three specimens 
of an undescribed darter while dip-netting 
for salamanders in Glen Spring at Bessemer, 
Jefferson County, Alabama. On 24 March 
1964, we visited the spring and obtained 51 
additional specimens. This distinctive spe- 
cies differs consistently from its nearest 
known relative, Etheostoma swaini (Jordan), 
in details of body proportions, squamation, 
pigmentation, development of lateral line 
and cephalic sensory canals, certain fin-ray 
counts, and habits. 

Counts and measurements were obtained 
by methods defined by Hubbs and Lagler 
(1958: 19-26) unless otherwise noted. 
Techniques of Hubbs and Cannon (1935) 


were used in making measurements to the 
nearest 0.1 mm. Proportional measurements 
are expressed as thousandths of the standard 
length. 

We wish to thank the following individ- 
uals who have aided us in this study: Dr. 
Ronald A. Brandon and Ron Altig of the 
University of Southern Illinois first collected 
specimens of this handsome new species and 
made them available to us; Dr. Herbert T. 
Boschung, Jr., our major professor, con- 
tinually encouraged us and gave many help- 
ful suggestions; Dr. Ralph Chermock of the 
University of Alabama criticized our manu- 
script in its early stages; Dr. Ralph Yerger 
of Florida State University permitted us to 
examine his unpublished data on Etheostoma 
swaint and also made radiographs for us; 
Dr. Royal D. Suttkus and John S. Ramsey 
of Tulane University made available to us a 
collection of the species described herein; 
Dr. Reeve M. Bailey of the University of 
Michigan criticized the final draft of our 
manuscript and made many. helpful sug- 
gestions. 


Etheostoma nuchale, sp. n. 
Watercress Darter 
CEig: 1) 

Material—The holotype, University of 
Michigan Museum of Zoology, UMMZ 
187523, an adult male, 39.4 mm in standard 
length, was collected by us on 24 March 
1964 in Glen Spring at Bessemer, Jefferson 
County, Alabama (NE'4 SEY Sec 17, T 
19S, R 4W) along county highway 20. In 


EDITORIAL COMMITTEE FOR THIS PAPER: 


REEVE M. BAILEY, Curator of Fishes, Museum of Zoology, University of Michigan, 


Ann Arbor, Michigan 


ROYAL D. SUTTKUS, Professor of Zoology, Tulane University, New Orleans, Louisiana 


RALPH W. YERGER, Professor of Zoology, Department of Biological Sciences, Florida 
State University, Tallahassee, Florida 


101 


102 


the same collection we obtained the follow- 
ing specimens: the allotype, UMMZ 187524, 
an adult female 39.8 mm in standard length; 
20 paratopotypes, UMMZ 187525; 20 para- 
topotypes, U. S. National Museum, USNM 
259800-F1; and 9 paratopotypes, University 
of Alabama Ichthyological Collection, UAIC 
1227. Twenty paratopotypes, Tulane Uni- 
versity No. 34591, were collected on 9 Sep- 
tember 1964 by Dr. Royal D. Suttkus, John 
S. Ramsey, and Francis L. Rose. 

At present this species is known only 
from the type locality in the Black Warrior 
River system of Alabama. 

Diagnosis—A species of Erheostoma of 
the subgenus Oligocephalus (Bailey and 
Richards, 1963) distinguished by: lateral 


line incomplete, moderately straight; supra- 
temporal canal incomplete; infraorbital canal 
usually incomplete; nape naked mesially; 
top of head, breast, and prepectoral areas 
naked; cheek largely naked but always with 
few to several embedded or exposed scales 


Tulane Studies in Zoology 


Vol. 12 


along posteroventral margin of eye; opercle 
with large exposed or embedded, ctenoid 
scales; body scales large, with 35-42 scales 
in the lateral series; 12-24 pored scales in 
lateral line; branchiostegal membranes mod- 
erately to narrowly conjoined, sometimes 
overlapping anteriorly. Fin-rays: dorsal VIII 
to XI (usually IX or X), 10 to 12; anal II 
(rarely III), 6 to 8; pectoral 11 or 12. Nape 
distinctly humped, usually decurving sharply 
to occiput. Breeding adults with a sub- 
marginal red band in spinous dorsal fin. 
Description—A moderately robust species 
with body slightly compressed; snout mod- 
erately pointed to somewhat rounded; pec- 
toral fin shorter than head length; 11 to 14 
branched caudal rays; 15 to 17 scale rows 
around caudal peduncle, of which 6 to 8 
(usually 7) are above the lateral series and 
6 to 8 (usually 7) are below; transverse 
scales are 10 to 12 (counted from origin of 
second dorsal fin posteroventrally to anal 
fin base); supratemporal canal incomplete, 


Figure 1. Top. Etheostoma nuchale, sp. n. Adult male holotype, 39.4 mm in standard — 


leneth (UMMZ 187523). 


Bottom. Etheostoma nuchale. Female allotype, 39.8 mm in standard length (UMMZ 


187524). 


No. 4 A New Darter 103 
TABLE 1. 
Comparison of Proportional Measurements of Etheostoma nuchale and E. swaini! 
erase: As Thousandths of Standard eee 
Species = Etheostoma nuchale Eine eicnes swaini 


Museum number UAIC 929, UAIC 
UMMZ UMMZ UMMZ UMMZ 1112,1113, 1060,1090, 
187523 187524 187525 187525 1150,1162 1162,1180 
Holotype Allotype Paratypes Paratypes and1184 and 1192 
Sex M F M F M F 
Number of specimens it 1 10 10 10 10 
Standard length, mm 39.4 39.8 384.9 36.6 35.9 37.3 
(30.6-38.3) (27.1-45.2) (25.9- ve 7) (28.9-44.7) 
Head length 281 282 280 274 29 295 
(264-293) varee 288) Ce 306) (270-313) 
Head width 167 164 176 171 162 1638 
(164-188) (162-181) (148-176) (148-178) 
Snout length 53 48 52 51 5S 55 
(45-61) (45-57) (43-60) (46-59) 
Orbit length 76 78 78 Han 85 87 
(72-86) (67-88) (75-93) (79-96) 
Fleshy interorbital 61 50 59 54 55 57 
width (54-62) (45-60) (50-63) (52-64) 
Upper jaw length U8) 78 13 Giz: 83 81 
(60-82) (65-78) (76-92) (74-97) 
Lower jaw to juncture 
of gill membranes 134 118 128 22, 124 123 
(110-152) (102-140) (115-1383) (114-135) 
Head depth at occiput 188 196 199 194 186 190 
(193-216) (180-206) (172-200) (177-202) 
Body depth at dorsal 
origin 226 241 228 228 PCA 210 
(212-238) (216-244) (196-231) (190-242) 
Body width 150 15S 148 148 142 152 
(131-161) (132-162) (134-151) (1385-172) 
Longest pectoral ray 239 234 243 239 274 268 
(231-255) (221-252) (249-301) (223-284) 
Pelvic fin length 206 204 220 210 224 214 
(193-234) (187-2387) (191-239) (191-224) 
Pelvic fin base 38 38 37 35 40 35 
(33-40) (33-37) (36-44) (31-39) 
Transpelvic distance 79 70 74 69 83 79 
(69-78) (66-72) (80-86) (76-87) 
Interpelvic space 15 18 16 16 20 19 
(13-20) (13-20) (14-23) (16-22) 
Pelvic insertion to 
juncture of gill 
membranes 180 191 186 180 190 LO9 
(177-195) (172-195) (175-204) (170-218) 
Highest dorsal spine aL aly/ 123 145) 109 138 25 
(113-141) (97-124) (128-154) (104-133) 
Highest dorsal soft ray 165 158 167 156 167 158 
(153-179) (187-168) (151-180) (142-166) 
First anal spine 1) 78 85 74 85 80 
(76-96) (67-97) (74-96) (69-93) 
Highest anal soft ray IZ 156 166 155 Ji LExy 
(154-177) (140-171) (187-166) (127-150) 
Caudal peduncle length 223 262 247 248 260 259 
(235-263) (227-262) (234-282) (242-267) 
Caudal peduncle depth 127 118 lias} PL, 118 P15 
(118-130) (102-130) (106-128) (108-129) 
Caudal fin length 195 211 216 221 230 22 
(190-248) (191-246) (210-262) (202-246) 


1 All specimens of E. swaini from the Black Warrior River system 


104 Tulane Studies in Zoology Vol. 12 
TABLE 2. 
Frequency Distribution of Fin-Ray Counts in Etheostoma nuchale and E. swaini! 
Dorsal Spines Soft Dorsal Rays 
Species 
VITL TEX x XI XII N Mean 1 alk ale} 18 N Mean 
E. nuchale 7 Sy ileal! 1 Gil Sale yet) ale} Bye alae, 
E. swaini 17 32 2 51 10.70 i) shal ie epee ILO 
Anal Spines Anal Soft Rays 
Species : 
Il 10 Ge N 6 tf 8 N Mean 
E. nuchale 50 1 51 3 41 i bile 0s 
FE. swaini 51 al 1133 35 3 51 ~=6.80 
ae Total Pectoral Rays (both sides) Branched Caudal Rays 
s 
ala 22 23 24 25 26 27 28 29 N Mean 11 12 13 14 15 16 N Mean 
E.nuchale 16 4 31 Hil Seco Hd Ae, 44 18.30 
EB. swaini Gf 8 8S. Boe al sal BHGil 3 12 24 5) aoe4beeiSaniG 


1 All EB. swaini from Black Warrior River system 
* Atypical fin has count of III, 7 


TABLE 3. 


Frequency Distribution of Scale Row Counts in Htheostoma nuchale and E. swaini! 


Scales In Lateral Series 


Species = : 
a aul Be Bia Biel Tats aN Bie aes ie) ae wok ele ais aa N Mean 
E. nuchale AP 2Z SS se uke 0 4 1 i 51 Sule Oe 
FE. swaini ly = & 8 8 8 38 5 33 al 39.84 
. 7 _ Seales In Transverse Series 
10 ala ite, 13} N Mean 
EB. nuchale ye 23 5 Il 10.65 
BE. swaini 2 35 183 al Hill 1 LAS 
; 5 a 7 Scales Around Caudal Pedunele 
15 16 iby 18 19 N Mean 
E. nuchale 9 40 2 51 15.86 
EB. swaini 9 28 10 4 51 17.18 
1 All EF. swaint from Black Warrior River system 
TABLE 4. (Continued on opposite page) 
Development of Lateral Line in Etheostoma nuchale and EF. swaini! 
So Pored Seales In Lateral Line 
Speci = ==, - a 
Deore 12°18 14 15 16 I1% 18 19 20 21 Sosa 
EF. nuchale 3 3 4 5 7 4 lh 8 1 7 — i i 
E. swaini 
: : ‘ Unpored Scales In Lateral Series 
ppeces 3.4 5 6 9% & -9 10 ii if “13 ae 
E. nuchale 4 il 


BE. swaint 1 5 4 10 2 qf 5 5 2 


1 All EF. swaini from Black Warrior River system 


No. 4 


with 2 pores on each side branch; lateral 
canal complete with 5 (rarely 4 or 6) pores; 
postorbital, coronal, interorbital, posterior 
nasal, and anterior nasal pores present; pre- 
operculomandibular canal complete with 10 
pores; anterior portion of infraorbital canal 
separated from posterior portion in 85 per 
cent of specimens; infraorbital pores usually 
3 + 5 (posterior plus anterior pores) but 
varies from 1 + 5 to 4 + 6 with several 
intermediate combinations. In two of 51 
specimens the infraorbital canal is inter- 
rupted twice with pore counts of 3 + 1 + 4 
and 2+ 1 + 3; one specimen has the canal 
interrupted three times with pore counts 
of 1 + 2 + 2 4+ 3; infraorbital canal com- 
plete with 8 pores in 15 per cent of speci- 
mens. The upper lip is bound to the snout 
by a well developed frenum; branchiostegal 
rays 6; vertebrae 34 or 35 (mean = 34.4) 
in counts made from radiographs of 15 
specimens; holotype with 34 vertebrae; 
nuptial tubercles absent; genital papilla of 
breeding females is a short, blunt, somewhat 
conical tube; pored portions of lateral line 
conspicuous, being nearly devoid of pig- 
ment; humeral region beneath the semi- 
transparent opercular membrane is darkened; 
sexual dimorphism is pronounced; general 
body outlines are shown in Fig. 1. Body pro- 
portions are given in Table 1. In Tables 2-4, 
counts for the holotype appear in boldface. 

Coloration—Sexual dichromatism is pro- 
nounced. Breeding males are brilliantly col- 
ored, breeding females are plain. The fol- 
lowing description is of the holotype, a 
breeding male. Notes were made immedi- 
ately after preservation. Five dark orbital 
bars are present on the head. A black bar 
which originates behind and just below the 
center of the eye extends backward and 


A New Darter 


105 


slightly upward almost to the origin of the 
lateral line. This postorbital bar is broken 
immediately anterior to the upper portion 
of the preopercular margin. A_ preorbital 
dark bar which originates in line with the 
center of the eye extends abruptly down- 
ward and forward, passing just below the 
anterior naris; it then continues along the 
outer edge of the premaxillary frenum and 
ends on the upper border of the premaxilla. 
The lower lip is densely punctated with 
melanophores near its midline. A dark sub- 
orbital bar subequal in width to the pupil 
extends downward and slightly forward and 
ends on the interopercular margin. In the 
interorbital area is a very short supraorbital 
bar which begins on the iris slightly posterior 
to the mid-dorsal edge of the orbit and ex- 
tends about one-third the distance to the 
mid-dorsum. Halfway between the supra- 
orbital and postorbital bars is a dark bar 
which extends obliquely backward to the 
supratemporal canal at a 45 degree angle 
to the postorbital bar. The cheek and breast 
are light gray with distinct, evenly scattered, 
stellate melanophores. The isthmus and 
branchiostegal membranes are darker than 
the breast. There is no prepectoral spot; 
the melanophores at the pectoral fin base 
are widely and evenly distributed. The 
humeral region beneath the semitransparent 
opercular membrane is dark. The lateral 
line is without dark pigment, and forms a 
conspicuous light line. The pupil is blue- 
gray. The iris is metallic gold. Each body 
scale is margined with melanophores. A 
large dark spot is present in the center of 
most body scales giving an appearance of 
horizontal lines along the body (Fig. 1). 
The genital papilla and the region immedi- 
ately surrounding the anus is white. The 


TABLE 4. (Continued) 


Development of Lateral Line in Etheostoma nuchale and FE. swaini) 


Pored Seales ia luatenal Line 


26 27 28 29 30 381 32 33 35 36 37 38 N Mean 
51 17.21 

Oe oa) be. dey ae Sisal; ates Gales | 51 32.65 

' Unpored Scales In Lateral Series a 

7 948 19 -20 21 22 23 24 26 27 N Mean 
Ms) 8s 40. 8 BS 8 ie a 51 20.41 
Bil 7.06 


1 All FE. swaini from Black Warrior River system 


106 


belly is bright red-orange ventrolaterally. 
On the mid-venter the red-orange is broken 
by a narrow light stripe which extends from 
the anal area to the interpelvic region. The 
bright red-orange of the belly fades abruptly 
into light yellowish-white at the fourth scale 
row below the lateral line. There are six, 
poorly defined vertical bars best developed 
on their lower halves on the posterior half 
of the body. The bars are two to three scale 
rows wide, bluish-brown in color, and are 
separated by poorly defined orange bars. 
Ventrally the red-orange of the belly extends 
posteriorly uninterrupted to the middle of 
the anal fin base where it is broken by the 
first complete vertical bar. The nape has 
an irregular-edged, light yellow stripe which 
extends uninterrupted along the mid-dorsum 
from the base of the first dorsal spine to 
the occiput. There are seven highly irregu- 
lar dorsal saddles which are two to four 
times wider than the interspaces. There 
are three indistinct, black spots in a vertical 
series at the caudal fin base. Immediately 
behind the basicaudal spots are two large, 
round orange spots, one above the other. 
The orange spots extend a short distance 
onto the caudal fin. Except for the orange 
spots, the basal third of the caudal fin is 
blue; remainder of fin is clear. Melano- 
phores on the caudal fin are confined chiefly 
to the rays while chromatophores are on 
rays and membranes. The anal fin is bright 
blue. The pelvic fins are blue basally be- 
coming lighter toward the tips. The pectoral 
fins are largely clear, becoming light blue 
basally. Pectoral rays are evenly outlined 
with melanophores. Listed in sequence from 
fin margin to fin base, the first dorsal fin 
has the following color bands: (1) a mar- 
ginal blue band, (2) a submarginal red- 
orange band, (3) another blue band, and 
(4) a basal red band. Listed in like order, 
the second dorsal fin has the following color 
bands: (1) a wide marginal blue band, 
(2) a submarginal light orange band, (3) 
an intense red band, (4) a blue band, and 
(5) a basal red band. 

In breeding male paratypes the coloration 
of the cheeks, breast, and prepectoral region 
varies from immaculate white to dark gray. 
The belly is light orange, red-orange, or 
bright red. Prepectoral spots are present or 
absent. Larger specimens usually have the 
nape mottled while most smaller specimens 
possess a conspicuous light stripe extending 


Tulane Studies in Zoology 


Volz 


along the mid-dorsum from the base of the 
first dorsal spine to the occiput. A few 
specimens have a vertical red bar near the 
middle of the caudal fin. Patches of red 
pigment are sometimes present on the anal 
fin. Dorsal saddles are highly irregular, vary- 
ing in number from 4 to 9. 

Females, in contrast to the brilliant nup- 
tial colors of males, are plain. Dominant 
colors in females are brown and black which 
contrast sharply with the white of the belly, 
breast, cheeks, and other light areas. Melano- 
phores are concentrated in the center of 
many body scales but do not produce hori- 
zontal lines as in males. The dorsum and 
sides of most females have interspersed 
black, brown and white spots which form 
no definite pattern (Fig. 1). Head colora- 
tion is similar to that of males. Five orbital 
bars are present. The nape is irregularly 
mottled in some specimens while most pos- 
sess a prominent predorsal light stripe. The 
prepectoral spot is present or absent. Dorsal 
saddles are usually highly irregular, varying 
in number from 3 to 9. The median fins 
have rows of discrete black spots on the rays. 
The black spots are boldly contrasted against 
the clear interradial membranes. The pec- 
toral fin rays are usually margined with 
melanophores while the interradial mem- 
branes are clear. The pelvic fins have me- 
lanophores on rays and membranes. The 
spinous dorsal is the only fin with bright 
color in breeding females, being similar to 
males but much subdued. 

Habitat and habits—The type locality, 
Glen Spring, is a limestone spring which 1s- 
sues from the base of Glen Hill and forms a 
small, clear creek 2-9 feet wide and 2-18 
inches deep. The creek flows into a man- 
made lake approximately 200 yards north 
of the spring basin. The estimated discharge 
of the spring at the date of collection was 
500 gallons per minute. This flow is par- 
tially dependent upon recharge from local 
precipitation. The flow was greatly reduced 
during a long dry period in November 1964 
but was restored December 1964, after the 
drought ended. The temperature of the 
spring varies narrowly between 16 and 18 
degrees Centigrade. The elevation at the 
spring is 480-500 feet above sea level. Glen 
Spring is located within the small portion 
of the Valley and Ridge Physiographic Prov- 
ince which extends into the eastern part of 
the Black Warrier River Basin. 


No. 4 A New 


The outflow creek is choked with dense 
growths of watercress, Nasturtium officinale. 
The stream bottom consists of angular gravel 
in riffle areas and silt and mud in areas of 
reduced flow and heavy watercress growth. 
Etheostoma nuchale is very habitat specific; 
it is found only among the watercress. We 
have observed nuchale as it perched upon 
the leaves and roots of watercress at mid- 
water depths. There it feeds upon the 
abundant snails, crustaceans, and insect lar- 
vae which inhabit the spring and outflow 
creek. In aquaria, nwchale moves about 
freely, perching here and there upon roots 
and leaves of aquatic plants. It does not 
normally inhabit the bottom as do most 
darters. E. nuchale can be collected almost 
anywhere along the stream course above the 
lake. It is absent below the lake where the 
stream becomes heavily polluted. The stream 
below the lake runs into Halls Creek which 
flows through a residential section of Besse- 
mer, Alabama. 

We have collected in other springs in the 
Birmingham-Bessemer area but have not 
taken nuchale. Most of the springs have 
either been exploited for public or industrial 
water supplies or have otherwise been al- 
tered. Glen Spring is located approximately 
twenty yards off the present Jefferson 
County Hwy. 20. The outflow creek closely 
parallels the highway. E. nuwchale is in dan- 
ger of extinction on the basis of its limited 
habitat alone. At present we are contem- 
plating the transplantation of muchale to 
other suitable springs in the area. 

E. nuchale is abundant and very success- 
ful in the spring basin and outflow creek. 
Associates of nuwchale are, in order of de- 
creasing abundance, Semotilus atromaculatus 
(Mitchill), Lepomis cyanellus Rafinesque, 
Etheostoma whipplei artestae (Hay), and 
Campostoma anomalum (Rafinesque ). 


Darter 107 


Relationship —Etheostoma nuchale is ap- 
parently a highly specialized derivative of 
E. swaini (Jordan), from which it is geo- 
graphically isolated. E. nuchale is known 
only from the type locality which is above 
the Fall Line in the Black Warrior River 
system of Alabama. FE. swatnz normally does 
not cross the Fall Line and is a wide-ranging 
species found along the Gulf Coastal Plain 
from the Ochlockonee River in Florida to 
the Amite River system of Southeastern 
Louisiana and southern Mississippi (R. W. 
Yerger, personal communication). We have 
made no attempt to study variation of E. 
swaini throughout its range as this problem 
is currently being investigated by Dr. Ralph 
W. Yerger of Florida State University. Since 
E. nuchale is such a distinctive species, it 
has been compared only with specimens of 
swaim from the Black Warrior River system 
(Tables 1-5). All specimens of swaini are 
deposited in the University of Alabama 
Ichthyological Collection and have the fol- 
lowing accession numbers: UAIC 677, 679, 
929, 1060, 1112, 1113, .1150, 1161, 1162, 
1180, 1192, 1225, 1582, all from Tuscaloosa 
Co., Ala.; UAIC 1184 and 1190 from Fayette 
Co., Ala. 

Breeding males of nuchale and swaini 
have the same basic color pattern with the 
colors being more intense in nuchale. Fe- 
males of nwchale and swaimi differ markedly 
in color pattern: in swam there are dark 
spots in the center of most body scales 
which usually produce definite horizontal 
lines along the body (Fig. 2); in nachale 
there are many darkened scales but horizon- 
tal lines are not usually developed (Fig. 1). 
Other color differences are also apparent. 

Seventy-three per cent of 51 specimens 
of swaini had either embedded or exposed 
scales on the nape. In nwchale the nape is 
always naked mesially. 


TABLE 5. 


Comparison of Etheostoma nuchale and 


E. sw aini} 


Character 


; jae Wenale 


E. swaini 


Supratemporal canal 
Infraorbital canal 

Pored lateral-line scales 
Unpored lateral-line scales 
Dorsal spines 

Total pectoral rays 

Scales in transverse series 
Scales around caudal peduncle 


15-17 (x 15-86) 


Widely interrupted Complete 
Usually interrupted Complete 
12-24 28-38 
15-27 3-11 
VATTEXT (Ge -91'2,) D,GU (Ge ILO (0) 
22-24 (X=) 23229) 24-29 (X = 25.61) 
Usually 10 or 11 Usually 11 or 12 


1All E. swaini from Black Warrior River system 


108 


Tulane Studies in Zoology 


Vol. 12 


Figure 2. Top. Etheostoma swaini. Adult male, 41.8 mm in standard length, from 


Black Warrior River system (UAIC 1184). 


Bottom. Etheostoma swaini. Adult female, 44.7 mm in standard length, from Black 


Warrior River system (UAIC 1090). 


Body proportions (Table 1) as well as 
visual comparisons (Figs. 1-2) show that 
nuchale is much more robust than the 
slender, stream-dwelling swam. Since nuch- 
ale lives among dense growths of water- 
cress where water movement is very slow, 
the deep, robust body is probably a habitat 
adaptation. A distinctive feature of nachale 
is the humped nape which decurves sharply 
to the occiput. The humped nape does not 
seem to be associated with breeding activities 
since it is well-developed, even in juveniles 
of nuchale. It is absent in swarm. It is in- 
teresting to note that a few gravid females 
of nuchale were present in collections made 
from March through July. Under relatively 
constant environmental conditions of the 
spring, the breeding season of muchale may 
be extended. We suspect that swamni of the 
Black Warrior River system breeds in early 
spring. 

The following characters of nuchale 
probably represent increased specialization 
over those of swaini: (1) reduced number 
of pored lateral-line scales, (2) incomplete 


supratemporal canal, (3) incomplete infra- 
orbital canal, (4) reduced number of pec- 
toral rays and dorsal spines, (5) increased 
sexual dimorphism and dichromatism, and 
(6) highly specific habitat. E. nuchale has 
probably evolved, as an isolated population, 
in response to relatively constant conditions 
encountered in the spring environment. 

Name.—tThe specific name, nuchale, “pet- 
taining to the nape’, calls attention to the 
light predorsal area and to the humped nape. 
The vernacular name, “watercress darter,” 
is suggested in reference to its habitat. 


LITERATURE CITED 


BAILEY, R. M., and W. J. RICHARDS. 1963. 
Status of Poecilichthys hopkinsi Fowler 
and Etheostoma trisella, new species, Per- 
cid fishes from Alabama, Georgia, and 
South Carolina. Occ. Papers Mus. Zool. 
Univ. Mich., 6380: 1-21. 

Hupss, C. L., and M. D. CANNON. 1935. 
The darters of the genera Hololepis and 
Villora. Misc. Publ. Mus. Zool. Univ. 


Mich., 30: 1-98. 

SGANS. oA RS UL eee and K. F. LAGLER. 1958. 
Fishes of the Great Lakes region. Cran- 
brook Inst. Sci. Bull. 26: xiii + 218 p. 


————a 


October 11, 1965 


EARLY DEVELOPMENTAL STAGES OF THE ROCK SHRIMP, 
SICYONIA BREVIROSTRIS STIMPSON, REARED IN 
THE LABORATORY! 


HARRY L. COOK 
and 
M. ALICE MURPHY, 


Bureau of Commercial Fisheries, 
Galveston, Texas, U.S. A. 


CONTENTS 
Page 
I. INTRODUCTION Eee eae eS oe ERE RRO NT OP ea Ce Eee Cee ED 109 
Il. METHODS AND MATERIALS _ 110 
III]. DESCRIPTION OF STAGES 110 
iN, TER a ea lee ee a eee SO 110 
NG AUT CaS 0 Sa eSB 0 ee ee ee a ee 110 
Gee TTS) TG He en NE 
ee INauplins Ws <A ss oe ea 
Pep Namplius lV 20 as tS lal 
121 “ISTE Sd Seep aae ei a ane ed leah 52 eA A ee SOM Re ade eA, ele AR IE a 
GreProtozocale se ea 12 
H. Protozoea II __ LS 
eroro7Ocatile Ae 5 ty tare es Seal 2 Wa ea ee Sy Se 
ee lysisilt ces ee eee OE eS ae a eee oe ta eee NS iat) 
Lc [OUT 4S) ROT i SAE a A Ss flr gee EPPO AY eR ES Se ae 119 
Aram Ny ESP IA ee oh a yg DO Sad Set ce oe 1:22 
INeeeOstiahvak 92 ee ee 123 
ne We EIRONOLOGY. OF LARVAL-DEVELOPMENT-2 222. ee 123 
V. COMPARISON WITH DEVELOPMENT OF OTHER Sicyonia 123 
RAE SUPNONMAR 1a a Ts Oe Se Oe See ee ae 126 
Site DTP EERATURE GITEDs..... ¥en 126 


ABSTRACT 


Five nauplial, three protozoeal, four 
mysis, and the first postlarval stages 
of the rock shrimp, Sicyonia brevirostris 
Stimpson, reared from eggs spawned 
in the laboratory, are described and 
illustrated. 


1 Contribution No. 203, Bureau of Com- 
mercial Fisheries Biological Laboratory, 
Galveston, Texas. 


I. INTRODUCTION 


Fishery scientists at the Bureau of Com- 
mercial Fisheries Biological Laboratory in 
Galveston, Texas are studying the early life 
histories of Gulf of Mexico Penaeidae as 
part of an overall effort to establish relation- 
ships between the oceanic environment and 
the populations of commercially important 
shrimps. The effects of such variables as 


EDITORIAL COMMITTEE FOR THIS PAPER: 


WILLIAM W. ANDERSON, Laboratory Director, Bureau of Commercial Fisheries, 
U. S. Fish and Wildlife Service, Brunswick, Georgia 


SHELDON DOBKIN, Assistant Professor of Zoology, Florida Atlantic University, Boca 


Raton, Florida 


ROBERT M. INGLE, Director of Research, Division of Salt Water Fisheries, Florida 
Board of Conservation, St. Petersburg, Florida 


109 


110 


temperature, salinity, and circulation, as well 
as the success of spawning, cannot be accur- 
ately assessed until specific identification of 
the various larvae is possible. The larvae of 
penaeid shrimps, especially during the nau- 
plial stage, are remarkably similar, and 
least 13 penaeid species occur in the north- 
western Gulf of Mexico. To insure accurate 
identification of those larvae belonging to 
the genus Penaeus, the group of primary 
importance, we must also be able to distin- 
guish the larval stages of associated non- 
commercial penaeids. This report describes 
the early development stages of one of these 
species, Stcyonia brevirostris Stimpson. 

Accoiding to Lunz (1957), 8. brevirostris 
occurs on the ea ae shelf of the west- 
ern Atlantic from just south of Norfolk, 
Virginia, around the Gulf of Mexico to Yu- 
catan. It appears to be confined inside the 
50-fathom contour, reaching greatest abun- 
dance at 35 to 40 fathoms. At points 
throughout its range, this shrimp occurs in 
considerable numbers. It is not fished com- 
mercially, but since it has a very agreeable 
taste and attains a relatively large size, it is 
generally regarded as having potential com- 
mercial value. 


Il. METHODS AND MATERIALS 


All descriptions and figures are from speci- 
mens reared in the laboratory. Gravid fe- 
males were caught at sea and transported to 
the laboratory. Spawning took place in a 
fiberglass aquarium that contained 80 liters 
of aerated, noncirculating sea water. The lar- 
vae were then maintained in the aquarium 
until the first postlarval stage was reached. 
Cultures of a diatom, Skeletonema sp., were 
added as food at the first protozoeal stage 
and brine shrimp, Artemia sp., were intro- 
duced at the first mysis stage. 

Temperatures during rearing varied be- 
tween 21.0° and 24.6° C. Salinity, which 
was 24.5%. at the start, rose to a maximum 
of 27.4%. The pH varied from 8.06 to 8.20. 

Samples of larvae to be used for descrip- 
tive purposes were taken periodically and 
preserved in 5% buffered formalin. The un- 
stained larvae were illustrated with the aid 
of a Camera Lucida. Dissection of the ap- 
pendages was performed in formalin on a 
plastic slide. 

The figures illustrating each substage de- 
pict an average larva. With the exception 
of the nauplial and protozoeal antennae, the 


Tulane Studies in Zoology 


Vole? 


appendages on these figures are intended to 
show only relative size and position, not 
setation or segmentation. To illustrate mor- 
phological details that would otherwise be 
obscured, we rotated the antennae of the 
nauplial substages on their axes. Figures of 
the mouth parts and other appendages repre- 
sent a single appendage taken from one in- 
dividual. In order to present a clearer figure, 
the setules on the setae were usually omitted. 
Measurements are given in mm. 

The following abbreviations are used in 
the text: TL = total length, including the 
rostrum but excluding the caudal spines; 
W = mean width at the point of greatest 
width; CL = carapace length, including the 
rostrum; N — number of specimens. 

The adult from which the larvae were ob- 
tained was identified according to Anderson 
and Lindner (1943) and Lunz (1945). 
Both the adult and the larvae have been de- 
posited in the museum of the Bureau of 
Commercial Fisheries Biological Laboratory, 
Galveston, Texas. 


III. DESCRIPTION OF STAGES 
A. Ege (Rios) 

Viable eggs of S. brevirostris are round, 
golden brown in color, and translucent. Eggs 
measured soon after spawning were 0.23 
mm in diameter. As the nauplius developed 
within the egg, the diameter increased to 
0.27 mm just prior to hatching. 


Go Va 


Late eggs showing developing 
a. lateral view b. ventral view. 

Hatching was observed only once. The 
nauplius filled the egg case and the furcal 
spines were already protruding when it was 
first noted. The nauplius appeared to flex, 
straightening out the first and second ap- 
pendages and pushing the eggshell off the 
anterior end of its body. 


B. Nauplius I (Fig. 2) 

Mean TL = 0.30 mm (0.28-0.32 mm) ; 
W = 017mm: N = 10 

Nauplii of 8. brevirostris exhibit the pyri- 


Figure 1. 


nauplii. 


No. 4 


form body that is typical of all penaeid lar- 
vae thus far described. A blunt labrum is 
present on the ventral surface and a slight 
protuberance arises from the dorsal surface 
of the body. 

An ocellus, which is retained in subse- 
quent nauplial substages, lies on the longi- 
tudinal axis of the body near the anterior 
end. 

The posterior end of the body is rounded 
and bears a pair of spines. 

Three pairs of appendages arise from the 
anterior portion of the body. The anterior 
ones (first antennae) are unbranched. The 
middle pair (second antennae) and third 
pair (mandibles) are branched into ventral 
endopods and dorsal exopods. 

Setae arising from the appendages are 
smooth, but in succeeding substages the 
longer ones become plumose. 

Color of the body and appendages is golden 
brown. The ocellus is black. Notes on color 
were not made for succeeding stages. 

Setation of appendages: 

First Antenna: Two short ventrolateral; 
a short spike and two long terminal; one 
long dorsolateral. 

Second Antenna: 

Endopod: Two short ventrolateral; two 
long terminal. 

Exopod: Three long ventrolateral; two 
long terminal. 

Mandible: Both branches bear three long 
setae. 

C. Nauplius II (Fig. 3) 
Mean TL = 0.31 mm (0.29-0.34 mm) ; 
W = 0.18 mm: N = 7 

The body is slightly more elongate than 
in the preceding substage. The posterior 
portion (edge) of the body between the 
single pair of caudal spines becomes flat- 
tened. 

Setation of appendages: 

First Antenna: Two short ventrolateral; 
one short, one long, and one medium termi- 
nal; one short dorsolateral. 

Second Antenna: 

Endopod: Two short ventrolateral; two 
long terminal. 

Exopod: Three long ventrolateral; two 
long and one short terminal. 

Mandible: Unchanged from Nauplius I. 


D. Nauplius Ill (Fig. 4) 
Mean TL = 0.35 mm (0.32-0.37 mm); 
W = 0.18 mm; N = 26 


Rock Shrimp. Development 


EE 


The body is more elongate than in Nau- 
plius II. Faint folds, the beginnings of ven- 
tral appendages, can be seen posterior to 
the labrum. The bases of the mandibles have 
become slightly swollen. A depression 1s 
present between the three pairs of caudal 
spines. 

Setation of appendages: 

First Antenna: One short and two me- 
dium ventrolateral; one medium, one long, 
and one short terminal. 

Second Antenna: 

Endopod: Two short ventrolateral; one 
short and two long terminal. 

Exopod: Four long ventrolateral; 
long and one short terminal. 

Mandible: Unchanged from Nauplius I. 


E. Nauplius IV (Fig. 5) 
Mean TL = 0.37 mm (0.33-0.40 mm) ; 
W = 0.18 mm; N = 30 

The body has become longer and the pos- 
terior portion more slender. The ventral ap- 
pendages that were first noted in the pre- 
ceding substage are more prominent, though 
still beneath the cuticle. These are the first 
and second maxillae and first and second 
maxillipeds. Two definite lobes have been 
formed at the posterior end of the body, each 
bearing five caudal spines. 

Setation of appendages: 

First Antenna: Two long and one me- 
dium ventrolateral; two long and one short 
terminal; one short dorsolateral. 

Second Antenna: 

Endopod: Two. short ventrolateral; one 
long and two medium terminal. 

Exopod: One medium and three long 
ventrolateral; two long, one medium, and 
one short terminal. 


Mandible: Unchanged from Nauplius I. 


two 


F. Nauplius V (Fig. 6) 
Mean TL = 0.44 mm (0.38-0.46 mm) ; 
W = 0.18 mm; N = 46 

The body is further elongated and the fur- 
cal processes are more pronounced, each giv- 
ing rise to seven spines. The maxillae and 
maxillipeds are now external, and show more 
advanced development. The swelling at the 
base of the mandible, which has become 
large and prominent, possesses a masticatory 
surface composed of several rows of small 
teeth. Both the endopod and exopod of the 
mandible are frequently hollow and trans- 
parent. The outline of a developing carapace 


112 
2 ae “= 
== ASE, 
e e 
Se — a — 
Ce = ‘s ae — 


/ Uy \ 
/| | Ny 
a 
dé 
b 
Sy \ ; GZ 
~~ \ y aay 
_}- 
ee g 
A 
EL VY; 
UY [ 
/ = 
| | 
Oo. 
NN Ei 
a 
——S 
= Zo ; 
Ss 
// | \ 
x 
/ \ 
Ol 
= 
“ e 
ne 
y [ fi AN WS 
Sf | WY /f | \\ 


}, 
ia 
/ \ 


Ol 
Figures 2-5, top to bottom. 2. Nauplhius I. 
a. ventral view b. lateral view. 3. Nauplius 
II, ventral view. 4. Nauplius III, ventral 
view. 5. Nauplius IV, ventral view. 


Tulane Studies in Zoology 


Vol. 12 


can be seen on the dorsal surface of the 
body, and frontal organs are present on its 
anterior margin. 

Setation of appendages: 

First Antenna: Two short and one me- 
dium ventrolateral; two long, one medium, 
and two short terminal; two short dorso- 
lateral. 

Second Antenna: 


Basis: One short ventrolateral. 

Endopod: Two medium and two short 
ventrolateral; one short and three long 
terminal. 

——- Yaa ———— 
= | <= 
\ le J 
& 
~ { ois — 
— > —_— 
Zz —— 
<a mon P <a ; ~ 
BEE y == AN 
Ws aN ‘ \\ 
‘ oN \ \\ 
Wali \ 
Ol 
| B 


Figure 6. Nauplius V. A. ventral view 
B. base of mandible. 


Exopod: Four long ventrolateral; three 
long, one medium, and one short terminal. 
Mandible: Unchanged from Nauplius I. 


G. Protozoeal (Fig. 7) 

Mean TL = 0.81 mm (0.70-0.99 mm); 
mean CL = 0.33 mm (0.30-0.36 mm) ; 
N= 3 

Body shape changes considerably with the 
molt to the first protozoeal substage. A 
large, loose-fitting carapace covers the an- 
terior section of the body. The posterior por- 
tion of the body has lengthened greatly and 
is now distinctly segmented. The maxillae 
and first and second maxillipeds are well 
developed and functional. 

The carapace is rounded with a median 
notch at the anterior end, a pair of rounded 
frontal organs being the only protuberances 
on it. The ocellus, which persists in subse- 
quent protozoeal substages, is present be- 
tween a pair of compound eyes that are 
visible beneath the carapace. The labrum 
does not bear a spine on its anterior margin. 
Two lobes of the labium, bearing short bris- 
tles on their inner margins, can be seen pos- 
terior to the labrum. Several teeth of the 


No. 4 


inwardly projecting mandibles can be seen 
between the labrum and labium. 

The first antenna is approximately twice 
the length of the endopod of the second an- 
tenna. It is composed of three major seg- 
ments. The basal segment, which is divided 
into five subsegments, bears one short seta. 
The second segment bears three setae, one 
short and one medium ventrolateral, and one 


Rock Shrimp Development 1s) 


short posterolateral. The disal segment bears 
three Jong and two short terminal, and one 
short posterolateral, setae. 

The second antenna is composed of a two- 
segmented protopod, an endopod of two 
segments, and an exopod of from seven to 
nine, frequently indistinct, segments. The 
protopod bears one seta at the juncture with 
the endopod. The first segment of the endo- 


Figure 7. Protozoea I. 
a. Ventral view ce. Maxilla I e. Maxilliped I 
b. Mandible d. Maxilla II f. Maxilliped II 


114 Tulane Studies in Zoology Vol. 12 


Figure 8. Protozea II. 
a. Dorsal view c. Maxilla II e. Maxilliped II 
b. Maxilla I d. Maxilliped I 


No. 4 


pod gives rise to a pair of setae from a point 
about one-third the length of the segment, 
and three terminal setae. The distal segment 
bears five terminal setae. The exopod bears 
five setae on its ventrolateral and two on its 
dorsolateral margins, as well as five term1- 
nal setae. 

The mandible has lost both the endopod 
and exopod. The masticatory process 1s 
longer than in the last nauplial substage and 
curves inward, terminating in a ring of teeth. 

The first maxilla consists of an unseg- 
mented protopod, a three-segmented endo- 
pod, and a small knoblike exopod. The pro- 
topod has two large lobes, each giving rise 
to several stout, toothed spines. The first and 
second segments of the endopod each bear 
two setae, and the third five. The exopod 
bears four setae. 

The second maxilla is comprised of an 
unsegmented protopod, a three-segmented 
endopod and a small knoblike exopod. The 
protopod has five lobes on its ventral mar- 
gin, the basal lobe bears about seven setae 
and the remainder two to five. The first 
segment of the endopod bears two setae, the 
second and third, three; the exopod bears 
five. 

The first maxilliped is longer than the 
maxillae and is biramous. It is composed of 
an unsegmented protopod, a four-segmented 
endopod, and an unsegmented exopod. The 
protopod has from 13 to 15 setae on its 
ventral margin. The first and third seg- 
ments of the endopod each bear two setae; 
the second, one; and the fourth, five. The 
exopod bears four lateral and three terminal 
setae. 

The second maxilliped greatly resembles 
the first, although it is somewhat smaller. 
The protopod bears two setae. The first 
three segments of the endopod each bear 
one seta and the fourth bears five. The exo- 
pod has three lateral and three terminal setae. 

The third maxilliped is small, biramous, 
and usually does not bear setae. 

The slender posterior portion of the body 
is divided into six thoracic segments and an 
unsegmented abdomen. The abdomen term1- 
nates in a well-developed, forked, telson, 


each lobe of which bears seven spines, the 


outermost etxending inward across the furca. 


Rock Shrimp Development 


115 


H. Protozoea Il (Fig. 8) 

Mean TL = 1.23 mm (1.12-1.44 mm); 
mean CL = 0.44 mm (0.38-0.45 mm); 
NSS 28 

The second protozoea is characterized by 
the presence of stalked compound eyes, a 
segmented abdomen, and a small rostrum 
which does not extend to the anterior edge 
of the body. 

The frontal organs have been lost and do 
not reappear in later substages. Small pa- 
pillae which are present on the dorsoanterior 
margins of the eyes persist in the third pro- 
tozoeal substage. 

Segmentation of the appendages remains 
almost unchanged from the preceding sub- 
stage. A dorsolateral seta has been added to 
the terminal segment of the first antenna. 
The number of spines on the second lobe 
of the protopod of the first maxilla has in- 
creased and an additional short seta is found 
on both the first and second segments of the 
endopod. Three setae have been added to 
the second maxilliped, one on the protopod 
and two on the endopod. Rudiments of five 
pairs of pereiopods are present posterior to 
the maxillipeds. 

The abdomen is divided into six seg- 
ments with the telson still part of the sixth. 
The number of caudal spines remains con- 
stant at seven pairs. 


I. Protozoea III ( Fig. 9) 

Mean TL = 1.96 mm (1.84-2.09 mm); 
mean CL = 0.58 mm (0.54-0.61 mm); 
NI= 20 

This substage can be distinguished from 
the second protozoea by the presence of 
biramous uropods and spines on the ab- 
dominal segments. 

The rostrum has undergone slight elonga- 
tion and now extends slightly past the an- 
terior margin of the body. 

The five subsegments which made up the 
basal segment of the first antenna in pre- 
ceding protozoeal substages have combined 
and three are now four segments. The first 
segment gives rise to one seta; the second 
and third, two; and the fourth, seven. In ad- 
dition to the two more prominent setae, a 
variable number of small setae now rim the 
distal portion of the third segment. 

The second antenna, maxillae, and second 
and third maxillipeds remain essentially the 
same as in the preceding substage. The seta 
on the second segment of the endopod of 


116 


Figure 9. Protozoea III. 


Dorsal view 
Maxilla I 


a. 


b. 


Tulane Studies in Zoology 


ec. Maxilla II 
d. Maxilliped I 


e. 


Maxilliped II 


Vol. 


No. 4 


the first maxilla in the preceding substage 
has been lost. Such condition might indicate 
a variable number of setae on this segment. 
A second seta is present on the second seg- 
ment of the endopod of the first maxilliped. 
Although the pereiopods have developed 
further and are biramous, they are still non- 
functional. 


Segmentation of the abdomen is more dis- 
tinct in this substage. Each of the first five 
segments bears a median spine on its dorso- 
posterior border. The fifth segment also has 
a pair of posterolateral spines, as does the 
sixth. 


The telson is now separated from the 
sixth segment and each lobe retains seven 
caudal spines. A pair of biramous uropods 
originate from the ventroanterior margin of 
the telson. The exopod is slightly longer 
than the endopod and five or six setae arise 
from its apex. The endopod usually has two 
very small terminal setae. 


J. Myszs I (Fig. 10) 

Mean TL = 2.47 mm (2.16-2.66 mm) ; 
mean CL = 0.82 mm (0.74-0.89 mm); 
NeS 24 

At the molt to the first mysis substage, the 
larva undergoes another fundamental modi- 
fication in body form, taking on a semblance 
of the adult for the first time. The trans- 
figuration is exemplified in the functional 
pereiopods with their long brushlike exo- 
pods, and by the transformation of the first 
and second antennae into the adult shape. 


The carapace has a short rostrum that ex- 
tends slightly less than half the length of 
the eye. A single spine is found on the dor- 
sal carina of the carapace. Supraorbital and 
pterygostomian spines are present. 


The ocellus and occular papillae persist 
in this and succeeding mysis substages. 


The first antenna consists of three seg- 
ments. The first segment, which is about 
twice the length of the second and third 
combined, bears two spines, one on its me- 
dian margin, and one on its lateral margin. 
The distal segment gives rise to two 
branches; the lateral, bearing five or six 
setae, is three times as long as the median, 
which bears a single seta. A series of setae 
are present along the margins of the append- 
age, and numerous setae arise from the apex 
of each segment. 


The second antenna is composed of a two- 


Rock Shrimp Development 


117 


segmented protopod (the basal segment is 
not shown in fig. 10), an unsegmented en- 
dopod with two lateral and three terminal 
setae, and an unsegmented, flattened exopod 
which bears 10 setae along its median and 
apical margins as well as a single, subterminal, 
externolateral seta. 


The mandible has undergone no appreci- 
able change. A short spine, added at the 
base of the second lobe of the protopod of 
the first maxilla, is the only difference. The 
exopod of the second maxilla has enlarged 
and now bears nine setae. An additional seta 
is present at both the apex of the protopod 
and on the endopod of the first maxilliped. 
The first and second segments of the endo- 
pod of the second maxilliped have each 
gained two setae, and two lateral setae have 
been lost from the exopod. 

The third maxilliped and five pereiopods 
have become enlarged and possess long un- 
segmented exopods which bear six to eight 
setae. The protopod of the third maxilliped 
is unsegmented and bears four setae. Its en- 
dopod is composed of four segments, the 
first giving rise to one seta; the second, none; 
the third, three; and the fourth, five. The 
protopod of the first pereiopod is two-seg- 
mented with only a single seta present on 
the second segment. The endopod of the 
first pereiopod has been modified to form a 
rudimentary chela bearing three setae. The 
other four pereiopods were not examined in 
detail. 

A ventromedian spine arises from each of 
the first five abdominal segments; the pleura, 
however, normally do not bear spines. Infre- 
quently, laboratory-reared mysis exhibited 
dorsoposterior spines on the fourth, fourth 
and fifth, or fifth segments. Since examina- 
tion of Szcyonia mysis from the plankton has 
failed to yield a specimen with dorsoposterior 
spines, their presence is tentatively regarded 
as an abnormal condition. The sixth seg- 
ment possesses a dorsomedian spine and a 
pair of posterolateral spines. 


The uropod has developed an unsegmented 
protopod which bears a posteroventral and 
a posterolateral spine. The endopod and ex- 
opod are of equal length and bears numerous 
setae on their margins. 

The telson, deeply cleft, bears six pairs of 
terminal and subterminal spines, and a single 
pair of lateral spines. 


118 


Tulane Studies in Zoology 


Figure 10. Mysis I. 
a. Lateral view e. Maxilla II i. Maxilliped III 
b. Antenna I f. Maxilla II j. Periopod I 
c. Antenna II g. Maxilliped I k. Telson 
d. Mandible h. Maxilliped II 


K. Mysis II (Fig. 11) 
Mean TL = 2.89 mm (2.70-3.15 mm); 
mean CL = 0.96 mm (0.90-1.05 mm) ; 
ING SS 

A second spine is added to the dorsal 
carina of the carapace and there is now a 
well-developed antennal spine. 

The first antenna remains unchanged, ex- 
cept that the developing statocyst can now 
be seen at the base of the appendage. The 
exopod of the second antenna now possesses 
a subterminal spine on its lateral margin and 
the number of median and apical setae has 
increased to 13. 


The mandible bears a large unsegmented 
palp. An exopod is no longer present on the 
first maxilla, and a seta has been lost from 
the second segment of the endopod. The 
endopod of the second maxilla has become 
further enlarged and the number of setae 
has increased to 24. 

The protopods of the three maxillipeds are 
composed of two segments. The terminal 
seta added to the protopod of the first max- 
illiped in the last substage is no longer 
present. The first segment of the endopod 
has also lost a seta. The endopod of the 
second maxilliped has gained a terminal seta. 


Rock Shrimp Development 


Wy. 


Figure 11. Mysis II 
a. Lateral view Maxilla II i. Pereiopod I 
b. Antenna I Maxilliped I j. Telson 


c. Antenna II 
d. Maxilla I 


rm mo 


A single seta has been added to both the 
first and second segments of the endopod of 
the third maxilliped. The chela of the first 
pereiopod now bears six setae. Rudiments 
of the branchiae are present as small lobes 
on the maxillipeds and pereiopods. 

The addition of small unsegmented pleo- 
pods and a reduction in the width of the 
cleft in the telson represent the only major 
changes in the posterior portion of the body. 


Maxilliped II 
Maxilliped III 


L, Myses III (Fig. 12) 

Mean TL = 3.51 mm (2.94-3.72 mm) ; 
mean CL = 1.13 mm (0.90-1.26 mm); 
N= 18 

An additional spine added to the dorsal 
carina of the carapace raises the count to 
three. 

The antenna have been modified slightly; 
the basal segment of the first antenna has 
gained a lateral spine apically, the endopod 


Tulane Studies in Zoology 


Volz 


Figure 12. Mysis III. 
a. Lateral view e. Maxilla I i. Maxilliped III 
b. Antenna I f. Maxilla II j. Pereiopod I 
c. Antenna II g. Maxilliped I k. Telson 
d. Mandibular palp h. Maxilliped II 


of the second antenna is now made up of 
three segments and its exopod bears 19 setae. 

The mandibular palp, composed of two 
segments, has enlarged further. The maxillae 
remain essentially unchanged from the pre- 
ceding substage. Rudiments of the gills are 
present on the three maxillipeds and _ first 
pereiopod. 

A seta has been added to both the first 
segment of the endopod and to the exopod 
of the first maxilliped. The endopod of the 
second maxilliped has gained an additional 
segment which does not bear setae. The dis- 


tal segment of its protopod has lost two setae, 
leaving the protopod with one seta, while the 
exopod and the second segment of the en- 
dopod each have an additional seta. The 
endopod of the third maxilliped has gained 
a segment, making a total of five. The first 
three segments of the endopod now possess 
two setae each; the fourth segment, three; 
and the fifth, five. The exopod of the third 
maxilliped and of each pereiopod is now 
composed of two segments. The endopod of 
the first pereiopod is composed of four seg- 
ments, with the distal segment being the 


No. 4 Rock Shrimp Development 121 


rudimentary chela. 

The posterior portion of the body has 
changed little. The pleopods, although now 
two-segmented, are still small. The cleft in 
the telson has become greatly reduced in size 


and the position of the spines has changed. 
There are now four pairs of terminal and 
three pairs of lateral spines. The postero- 
ventral spine on the protopod of the uropod 
is absent. 


Figure 13. Mysis IV. 
a. Lateral view 
b. Antenna I 


c. Antenna II 
d. Mandible 


rm mo 


Maxilla I 
Maxilla II 
Maxilliped I 
Maxilliped II 


i. Maxilliped III 
j. Periopod lI 
k. Telson 


M. Mysis IV (Fig. 13) 

Mean TL = 3.68 mm (3.48-3.81 mm) ; 
mean CL = 1.20 mm. (1.11-1.23 mm) ; 
NE= "10 

The fourth mysis differs only slightly from 
the preceding substage. The addition of a 
fourth rostral spine and a reduction in the 
cleft of the telson represent the most promi- 
nent modifications. The antennae have also 
undergone changes, with the endopod of the 
first antenna now composed of two segments, 
and that of the second, five segments. 


PAO 
Y — = 


Tulane Studies in Zoology 


Vol..12 


The distal segment of the endopod of the 
first maxilla has lost a seta. The number of 
setae on the exopod of the second maxilla 
has increased to 36 and, although not shown 
in Fig. 13f, the setation of the protopod and 
exopod remains unchanged. The second and 
fourth segments of the endopod of the first 
maxilliped have each lost a seta, and the 
exopod, two. The number of setae on the 
protopod of the second maxilliped, and that 
of the second and fifth segments of its 
endopod, has increased and decreased by 


Figure 14. Postlarva I. 
a. Lateral view e. Maxilla I i. Maxilliped III 
b. Antenna I f. Maxilla II j. Pereiopod I 
c. Antenna II g. Maxilliped I k. Telson 
d. Mandibular palp h. Maxilliped II 


No. 4 


one, respectively; its exopod is now two- 
segmented. 

The pleopods retain essentially the same 
shape, but have increased in length and are 
now about one and one-half times the length 
of those of the previous substage. 


N. PostlarvaI (Fig. 14) 

Mean TL = 3.87 mm (3.51-4.35 mm); 
mean CL = 1.13 mm (1.07-1.21 mm); 
N= 2 

With the molt to postlarva, the exopods 
are lost from the pereiopods and the pleo- 
pods, now heavily setose, are the principal 
swimming organs. 


The rostrum is short, extending about one- 
half the length of the eye. The carapace 
usually bears four teeth on its dorsal carina, 
although some specimens show a small fifth 
spine anteriorly. Hepatic and antennal spines 
are present, the supraorbital and pterygosto- 
mian spines having been lost. 


The ocellus persists, but the ocular papil- 
lae are no longer present. 


Although there is no appreciable change 
in the first antenna, the endopod ( flagel- 
lum) of the second antenna is elongate and 
composed of 16 segments, while the exopod 
(antennal blade) is very broad at its base. 


The mandibular palp has increased in size 
and bears about 20 setae along its margin. 
The endopod of the first maxilla is reduced 
greatly and is no longer setose. The endopod 
of the second maxilla is also vestigial, and 
the spines on the four lobes of the protopod 
are less prominent. The exopod has enlarged 
greatly and possesses about 60 setae. 


Both the endopod and exopod of the first 
maxilliped are greatly reduced in size and 
setation. The second maxilliped retains a 
greatly reduced exopod, while the third 
maxilliped and the pereiopods have lost their 
exopods. The second maxilliped has be- 
come recurved and bears numerous spinelike 
setae on the last two segments. The dactyls 
of the chelipeds are fully formed. Although 
still rudimentary, the branchiae on the maxil- 
lipeds and pereiopods have developed two 
rows of small protuberances on their external 
surfaces. 

The first five abdominal segments do not 
possess spines. The sixth segment has a 
small dorsomedian and a small pair of pos- 
terolateral spines. 

The uniramous pleopods have lengthened 


Rock Shrimp Development 12 


ree) 


and bear about 12 setae on the second seg- 
ment. 

The protopod of the uropod retains a small 
posterolateral spine. The endopod and exo- 
pod are of equal length. 

The telson is no longer cleft, ending in- 
stead in a blunt point. It bears five pairs of 
minute lateral spines and seven pairs of 
setae. 


IV. CHRONOLOGY OF LARVAL 
DEVELOPMENT 


Experiments by the authors with larvae of 
the brown shrimp, Penaeus aztecus Ives, 
showed that growth is closely related to tem- 
perature, becoming more rapid the warmer 
the water. Consequently, it is likely that the 
growth of S. brevirostris would also be ac- 
celerated at temperatures higher than those 
encountered during this rearing trial (21.0° 
to 24.6° C). 

In this study, the eggs were spawned at 
night and hatched the following afternoon. 
Each nauplial substage lasted approximately 
12 hours. The number of days after spawn- 
ing when the indicated substages were first 
noted are listed in Table I. 


TABLE 1 
Chronology of larval development 
Days after 
Substage spawning 
Protozoea I 3 
Protozoea II 6 
Protozoea III 10 
Mysis I WW 
Mysis II 16 
Mysist III ZZ 
Mysis IV 24 
Postlarva 1 29 


V. COMPARISON WITH DEVELOPMENT 
OF OTHER Sicyonta 


As has been described, the larvae of S. 
brevirostris pass through five nauplial, three 
protozoeal, and four mysis substages before 
molting to the first postlarval stage. This 
sequence differs from that of the larval de- 
velopment of other (littoral) penaeidae in 
the northern Gulf area, most of which pass 
through only three mysis substages (Cook, 
in press), as well as from that of larvae of 
other Sicyonia spp. described in the literature 
(Table 2). One reason for the variation 
among descriptions by different authors may 
be that the number of substages is influenced 
by the environment in which the larvae grow. 
For example, Pike and Williamson (1964) 


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126 


found that under certain conditions, larvae 
of Pandalus montagui Leach reared in the 
laboratory passed through several additional 
zoeal substages before molting to megalopa. 
To ensure that the number of substages listed 
for S. brevirostris in this paper is the same 
as occurs in nature, and was not affected by 
the rearing procedure, a comparison was 
made with Szcyonza larvae in plankton sam- 
ples. The number of substages found in a 
large volume of planktonic material was the 
same as that found among laboratory-reared 
larvae. 


Larvae of three other species of Szcyonia 
have been described: S. carinata by Heldt 

1938); S. stempsoni by Pearson (1939); 
and S. wheeleri by Gurney (1943). Upon 
comparing descriptions of these larvae with 
specimens of S. brevirostris, we determined 
that in the protozoeal and mysis stages they 
possess morphological characters which per- 
mit their differentiation both from other 
penaeid larvae and from each other. Vart- 
ation between nauplii of different Szcyonza 
often appears to be as great as that observed 
between penaeid genera at the nauplial stage, 
and there seemingly are no definitive char- 
acters by which they can be collectively sepa- 
rated from nauplii of other genera. This is 
due to the fact that penaeid nauplii are very 
simple forms having the same general shape 
and relatively few setae, all of which mini- 
mizes the possibility of distinctive, inter- 
specific variation. 


The following characters serve to distin- 
guish Szcyonta protozoeae from those of 
other penaeid genera: The first antenna is 
relatively long, about 114 times as long as 
the endopod of the second antenna, and bears 
three long terminal setae. The rostrum, when 
present, is very short with no supraorbital 
spines. The labrum does not possess a ven- 
tral spine, and the outer pair of caudal spines 
extends inwardly across the furcae. 


The lack of dorsomedial spines on the 
first five abdominal segments is usually 
sufficient criterion for identifying Szcyonia 
myses. Other useful characters are the pres- 
ence of ventromedial spines on the first five 
abdominal segments, and the absence of 
hepatic spines on the carapace. 

As pointed out by Heldt (1938), meta- 
morphosis among the Penaeidae is very grad- 
ual with relatively minor differences sepa- 
rating most substages. Because distinction 


Tulane Studies in Zoology 


Vol. 12 


of successive substages can only be accom- 
plished somewhat arbitrarily, different in- 
vestigators examining the same kind of de- 
velopmental material might easily have dif- 
ferent opinions as to the number of substages 
represented. We believe this subjectively 
largely explains the variation in substage 
count recorded for Szcylonta larvae (Table 
2). So, to facilitate comparison of the spe- 
cies described in Table 2, we have taken the 
liberty of placing the larvae of some authors 
in slightly different substage categories. 


VI. SUMMARY 


Five nauplial, three protozoeal, four mysis, 
and the first postlarval stages of the rock 
shrimp, Sicyonia  brevirostris Stimpson, 
reared from eggs spawned in the laboratory, 
are described and illustrated. Temperatures 
during rearing varied between 21.0° and 
24.6° C. Salinity, which was 24.5%o at the 
start, rose to a maximum of 27.4%. The pH 
varied from 8.06 to 8.20. Under these con- 
ditions, the larvae developed to the first post- 
larval stage in 29 days. 


S. brevirostris larvae are compared with 
corresponding substages of three previously 
described species of Szcyonia. It was noted 
that the larvae of all four species possess 
characteristics which serve to distinguish 
them from one another. 


VII. LITERATURE CITED 


ANDERSON, W. W., and M. J. LINDNER, 1943. 
A provisional key to the shrimps of the 
Family Penaeidae with especial reference 
to American forms. Trans. Amer. Fish. 
Soc., 73: 284-319. 


Cook, H. L., in press. A generic key to the 
protozoean, mysis, and postlarval stages 
of the littoral Penaeidae of the northwest- 
ern Gulf of Mexico. Fish. Bull. U.S. Fish. 
Wildlife Serv. 

GURNEY, ROBERT, 1943. The larval develop- 
ment of two Penaeid prawns from Bermu- 
da of the genera Sicyonia and Penacopsis. 
Proc. Zool. Soc. Lond., Ser. B., 118: 1-16. 


HELDT, JEANNE H., 1938. La reproduction 
chez les Cr ustacés Décapodes de la famille 
des Pénéides. Ann. Inst. Océanogr. Mona- 
co, 18: 31-206. 

LuNz, G. Ropert, 1945. Carolina shrimps of 
the genus Eusicyonia. The Charleston 
Museum Leaflet No. 20, 12 p., Charleston, 
So (G: 

, 1957. Notes on rock 
shrimp Sicyonia brevirostris (Stimpson) 
from exploratory trawling off the South 
Carolina coast. Contributions from Bears 


No. 4 Rock Shrimp Development 127 


Bluff Laboratories, No. 25, 10 p., Wadma- erus (Linn.). Bull. U. S. Bureau Fish., 
law Island, S. C. 49(30): 1-78. 

PEARSON, JOHN C., 1939. The early life his- Pike, R. B., and D. S. WILLIAMSON, 1964. 
tories of some American Penaeidae, chief- The larvae of some species of Pandalidae 
ly the commercial shrimp, Penaeus setif- (Decapoda). Crustaceana, 6: 265-284. 


October 11, 1965 


7 
: 
7 
a 
- 
7 


ea 


does oe 


i 


4h 


FISHES TAKEN IN MONTHLY TRAWL SAMPLES OFFSHORE OF 
PINELLAS COUNTY, FLORIDA, WITH NEW ADDITIONS TO 
THE FISH FAUNA OF THE TAMPA BAY AREA 


MARTIN A. MOE, JR. 


and 
GEORGE T. MARTIN, 
Florida Board of Conservation Marine Laboratory 
St. Petersburg, Florida 


ABSTRACT 


Monthly collections of fishes were 
made at nine stations offshore of Pinel- 
las County, Florida, from November, 
1962, to June, 1968. Data on 2,317 
fishes, representing 72 species, are re- 
ported. Occurrence of various species, 
relative abundance at certain depths 
and environmental descriptions are pre- 
sented. Growth and other biological da- 
ta are given for the 12 species most 
numerous in the catch. Salinity differ- 
ences were not considered significant 
since the observed range between high- 
est and lowest values was only 6%. 
Complete temperature data with a gen- 
eralized analysis are also presented. 
Distinctive differences in the fish fau- 
na at depth ranges of 15 to 18 ft, 25 
to 45 ft, and 75 to 105 ft are demon- 
strated. Fifteen of the species collect- 
ed are new to the ichthvofauna of the 
Tampa Bay area. Another 27 species 
new to the area are included, although 
they were not taken during the study. 
The number of fish species reported 
from the Tampa Bay area is extended 
to 312. 


INTRODUCTION 


This account, with the exception of new 
additions to the Tampa Bay ichthyofauna, 
concerns the fishes taken during sampling 
for adult shrimp at established stations off- 
shore of Pinellas County from November, 
1962 through June, 1963. This restriction 
limits the majority of the species listed to 


* Current address: Bears Bluff Labora- 
tory, Wadmalaw Island, South Carolina. 
Contribution No. 93 


the smaller, slow-moving bottom fishes. 
Data on 2,274 fish taken from November, 
1962, through June, 1963 and 43 fish taken 
prior to this period at the same stations are 
included in this account. This is a relatively 
small number, but it represents one of the 
most extensive systematic collections from 
offshore stations in the Gulf of Mexico. 


Since our study extended for only eight 
months, seasonal patterns exhibited by the 
fishes on their offshore range are not com- 
pletely disclosed. Sampling was conducted 
only at night and may have influenced the 
composition of the fish catch. Sampling was 
limited to one or two 15-minute trawls at 
each station using a 16-foot trynet (otter 
trawl). Obviously only a representation of 
the species present could be collected, thus 
these data are interpreted by species rather 
than by habitat. Effort at each station was 
not consistent because of inclement weather 
and unsuitable bottom for trawling. Some 
stations were trawled five times during the 
study and others were trawled up to 13 times. 
Except for one of the authors (Martin), the 
personnel and the vessel varied during the 
course of the study. 

Certain factors limit the value of all sys- 
tematic sampling programs of offshore bio- 
topes. Most important is the extreme diffi- 
culty of repeatedly sampling exactly the 
same area. The problems of determining 
exact position at sea are well known and 
need no elaboration here. We are reasonably 
certain that all of our samples were taken 


EDITORIAL COMMITTEE FOR THIS PAPER: 


Harvey R. BULLIS, JR., Base Director, Exploratory Fishing and Gear Research Base, 
U. S. Bureau of Commercial Fisheries, Pascagoula, Mississipp1 


GORDON GUNTER, Director, Gulf Coast Research Laboratory, Ocean Springs, Mis- 


sissipp1 


VICTOR G. SPRINGER, Associate Curator, Division of Fishes, U. S. National Museum, 


Washington, D. C. 


130 


from the same general area at each station. 
Our certainty is based on compass headings, 
running time, approximate depth, and visual 
orientation points for most stations. 

A primary work on the ecology of the 
Gulf fishes, conducted on the Texas coast, 
is by Gunter (1945). Many papers dealing 
with the biology of typical eastern Gulf of 
Mexico fishes of inshore, nearshore, or 
closely adjacent waters have appeared. The 
more extensive of these, in order of their 
geographic location from south to north, 
are: Longley and Hildebrand (1941) at 
the Tortugas Islands; Springer and McErlean 
(1962) at Matecumbe Key; Tabb and Man- 
ning (1961) at northern Florida Bay; Spring- 
er and Woodburn (1960) at Tampa Bay; 
Kilby (1955) at Cedar Keys and Bayport; 
Reid (1954) at Cedar Keys; Joseph and 
Yerger (1956) at Alligator Harbor; Miles 
(1951) at Apalachicola Bay; Bailey, Winn, 
and Smith (1954) at the Escambia River; 
Boschung (1957) at Mobile Bay; Gunter 
(1938) at Barataria Bay; and Darnell (1958) 
at Lake Pontchartrain. The locations of these 
studies are spaced over six degrees of north 
latitude and span approximately 1,000 linear 
miles of the Gulf of Mexico shoreline. 

Systematic analyses of the fishes taken dur- 
ing commercial shrimping operations in 
various offshore areas for the Gulf are pre- 
sented by Hildebrand (1954 and 1955) 
and the Florida Board of Conservation 

1951). These studies, especially those of 
Hildebrand, provide invaluable data on 
commercially important areas by listing the 
species present and their relative abundance 
in the catch. Even though very little hydro- 
graphic, seasonal, or specific habitat data 
were included in those studies, these papers 
form the bulk of our ecological knowledge 
of the shore fishes in the eastern sector, and 
offshore areas generally, of the Gulf of 
Mexico. 

Springer and Woodburn (1960) contrib- 
uted significantly to our knowledge of the 
biology and ecological relationships of fishes 
in the Tampa Bay area. The present paper 
extends this knowledge into the offshore 
range of several species, thus complement- 
ing their extensive work. 


STATION LOCATION AND DESCRIPTION 


Most stations are within the region af- 
fected by tidal flushing of Tampa Bay. Each 


station covered an area of one square mile 


Tulane Studies in Zoology 


Vol. 12 


and, with a few exceptions (primarily the 
stations farthest offshore), all samples were 
taken within this boundary. 


Two generalized bottom types were en- 
countered: a flat bottom of hard, fine sedi- 
ments isolated from any reef formations, and 
a flat bottom of coarse lightweight sediments 
in the immediate vicinity of limestone base 
reefs. The limestone reef environment is, ac- 
cording to Springer and Woodburn (1960), 
“one of the least known biocoenoses in the 
Gulf of Mexico.” Phillips and Springer 
(1960) reported on the algae typically found 
on these reefs and presented a physical de- 
scription of the general reef configuration. 
Springer and Woodburn (1960) and Moe 
(1963) also discussed the offshore reef en- 
vironment of this general area. These reefs 
were avoided as much as possible during our 
trawling, but as damaged nets testify, we 
were not always successful. Many of the 
fishes that appeared in Our nets are com- 
mon in the vicinity of these reefs: sparids, 
pomadasyids, sciaenids, and serranids. Small 
pieces of rocky reef, shell, and sponge were 
often taken in the nets also, thus we feel 
that we obtained many of the smaller fishes 
that dwell on or around the reef. 


Stations 2, 3, 4, and 6 are the only sta- 
tions that veld fish each month of the 
eight-month period, and these stations are 
essentially the basis of our analyses. A total 
of 2,050 fishes, representing 90.1% of the 
fishes taken during the eight months, were 
trawled at the above stations. Stations 1, 7, 
8, and 9 were not always fished and then 
only yielded fishes sporadically because of 
trawling difficulties. The production at these 
latter stations, 267 fishes collected in 14 suc- 
cessful trawl hauls, supplements the data 
from the four main stations. The stations 
are grouped according to the general depth 
range in which they occur to facilitate com- 
parisons. Stations 1 and 7 are respectively 
the shallow and deep extremes of the 1, 4, 
6, and 7 grouping. Stations 8 and 9, though 
not thoroughly sampled, indicate extensive 
changes in the fish fauna of the deeper 
waters. 


Stations 1 through 9 are mapped in Fig- 
ure 1 and the physical data for stations 1, 
2, 3, 4, 6, 7, 8, and 9 are cumulatively pre- 
sented in Table 1. Stations 4, 6, and 7 are 
in an area that is frequented by commercial 
shrimp harvesters. 


~ 


C ss 
eae 
~. ® TARPON SPRINGS 
i. Kgmeacatl 
iS U 4 ; 

Barod 10 fathoms = fathoms 7H | om 

iS es pS 
aG Se 
GULF Ss ~ Pe 
(™~ 
oF Se 
MEXICO . 


Figure 1. The Tampa Bay area and adja- 


cent offshore waters. Numerals indicate 
the locations of stations 1 through 9. 


STATION 1: 28°07’N 82°54°W 

Station | is the northernmost station and 
is least affected by the discharge of Tampa 
Bay, although the discharge of the Anclote 
River creates the same general environ- 
mental conditions. This station is located 
about four miles from the Anclote Key light- 
house of an azimuth of 228°. Depths ranged 
from 18 to 30 feet, but almost all specimens 
collected were taken within a few feet of 
the mean depth of 23 feet. 


Station 1 was trawled five times. Suitable 
bottom for trawling could not easily be 
found and this difficulty prevented consist- 
ent sampling. Trawls were generally made 
on a north-south axis whenever an area of 
flat bottom could be found. This station 
was especially destructive to our nets as they 
frequently caught on the bottom and were 
damaged. This was always the first station 
visited, thus our operations usually took place 
during the early hours of the night. Station 
1 typifies the general bottom type of coarse 
lightweight sediments in the immediate vi- 
cinity of limestone reefs. 


Station 1 was visually examined by the 
senior author with SCUBA gear to augment 
the fathometer recordings. These observa- 
tions were made during daylight on Novem- 
ber 19, 1963, on the northwest quadrant of 


Offshore Fishes from Florida 


the station. A flat bottom evenly covered 
with lightweight, coarse sediments mixed 
with a finer silt covered most of the area 
examined. This lightweight sediment layer 
(30 to 50 mm deep) could easily be dis- 
turbed and produced a dense cloud that 
settled in a matter of minutes. The sedi- 
ments became more compact and_ finer 
grained as they extended downward. The 
sediment surface was investigated to a depth 
of about 165 mm. Many small pieces of 
shell and coral were recognizable, and these 
became more frequent and larger as the sedi- 
ments graded into the rocky patch reef. There 
were one major and several minor patches 
of limestone rock reef in the area examined, 
a total of about 900 square yards of bottom. 
These rocky areas were 2 to 3 feet high and 
were very irregular with many cliffs, caves, 
and crevices. These reef areas were the 
center of almost all observed life. Attached 
invertebrates were profuse and formed much 
of the reef cover. Several large loggerhead 
sponges, Sphectospongia (vesparia?), were 
observed. One was measured and was ap- 
proximately four feet high and three feet 
across. Much of the general area offshore of 
Tarpon Springs has been described to a lim- 
ited degree by Dawson and Smith (1953) 
and de Laubenfels (1953) in conjunction 
with surveys on sponge disease. 

Many fish were observed during the dive, 
but few of these were taken during the sam- 
pling at night. Larger serranids, sparids, and 
pomadasyids were seen most frequently. 


STATION 23 27-5807 N82 DIO WwW, 

This station is located due west of Clear- 
water Beach about one mile offshore of the 
surf line. The buoy lights of the ship chan- 
nel to the south and prominent shore lights 
allowed rapid orientation during night sam- 
pling. Depths varied from 15 to 20 feet. 

Sampling conditions were always excellent 
at this station, thus a relatively large number 
of trawl hauls was made. Trawl hauls were 
made parallel to the beach, and always 
yielded many small fishes. 

Station 2 typifies the general bottom type 
of a flat surface of hard, fine sediments 1so- 
lated from any reef formations. Visual ex- 
amination was made by the senior author 
during daylight on November 19, 1963, and 
the following observations were recorded. 
The bottom was hard, flat, marked with low 
ripples, and consisted of homogeneous sedi- 


with a trynet unless otherwise specified. 


Tulane Studies in Zoology 


TABLE 1 
Data summary for all stations from November, 1962 to June, 1963. All tows were made 


Vol. 12 


Station 
ie 


bo 


Salinity %o 
Surface Bottom Surface Bottom Taken 


Depth 
Date No. of Tows (Ft.) 

Nov. 14, 1962 1 24 
Dec. 19, 1962 1 22 
Jan. 15, 1963 il 18 
Feb. 23, 1963 2 22 
Mar. 18, 1963 0 25 
Apr. 17, 1963 0 26 
May 12, 1963 1(dredge) 28 
June 4, 1963 1 24 

TOTALS ai 
Nov. 14, 1962 1 18 
Dec. 19, 1962 il aL 
Jan. 15, 1963 2, 16 
Feb. 23, 1963 2 20 
Mar. 18, 1963 2 aD 
Apr. 17, 1963 if 18 
May 138, 1963 i 18 
June 4, 1963 1 1H 
June 7, 1963 il 15 

TOTALS 12 
Nov. 15, 1962 i 18 
Dec. 20, 1962 2 Lg 
Jan. 16, 1963 2, 19 
Feb. 24, 1963 Ye 18 
Mar. 19, 1963 2 15 
Apr. 18, 1963 1 16 
May 18, 1963 1 2; 
June 5,1963 il WPA 
June 6, 1963 il 15 

TOWALS ie 
Nov. 15, 1962 1 30 
Dec. 20, 1962 il 32 
Jan. 16, 1963 1 30 
Feb. 24, 1963 2 28 
Mar. 19, 1963 2 30 
Apr. 18, 19638 1 33 
May 13, 1963 1 30 
June 5,1963 il Zit 
June 6, 1963 1 PAL 


TOTALS 


= 
= 


Discontinued prior to 


Nov. 15, 1962 
Dec. 20, 1962 
Jan. 16, 1963 
Feb. 24, 1963 
Mar. 19, 1963 
Apr. 18, 1963 
May 13, 1963 
June 6, 1963 


| RRR Ree rPNe 


S 


34.4 
33.4 
34.5 
31.2 
32.1 
35.0 
34.9 
36.7 


33.2 
32.3 
35.1 
31.8 
32.1 
34.5 
34.9 
36.1 
36.0 


32.6 
33.5 
34.8 
32.8 
32.8 
34.5 
35.6 
36.6 
36.1 


33.6 
34.0 
34.7 
34.0 
34.0 
35.9 
36.8 
56.8 
36.1 


33.1 
33.4 
35.5 
33.5 
34.8 
36.8 
36.9 
36.3 


34.4 
33.8 
34.8 
33.4 
32.8 
34.7 
34.9 
36.3 


33.4 
33.4 
34.4 
32.9 
32.5 
34.0 
35.5 
35.8 
35.7 


32.5 
34.1 
35.1 
33.0 
33.2 
34.6 
36.2 
36.6 
36.6 


34.6 
34.6 
35.7 
34.4 
33.8 
35.8 
37.0 
36.8 
36.0 


35.5 
34.7 
36.0 
33.3 
34.3 
35.7 
36.8 
36.3 


No. 

Temp. °C of Fish 
17.8 17.8 5 
see 12.4 17 
1S yaa 1 5ek 5 
14.6 14.3 14 
ones 22.0 0 
Pile 21-2 0 
2Ar2 24.6 0 
PAT 27.9 0 
41 
eA alyfes) 48 
13.6 Wags) 195 
Lass 15.4 119 
14.6 14.4 32 
24AE2 23.8 78 
22.0 22.0 45 
25.0 24.6 39 
27.8 28.0 a 
— — 78 
641 
eg IWS) 34 
13.6 ss 274 
16.0 16.0 44 
15.9 i525 35 
23.8 Doel: 394 
21.9 21.9 65 
Zon0 Ps | TY 
2Be2 28.5 3 
28.3 28.5 61 
927 
18.6 18.6 Jot 
13.6 NSe9 0 
16.0 16.0 ale! 
15.5 15.4 23 
Zane, ZAlR5 68 
Pall 2455 20 
24.6 22.0 5 
Pile 27.5 9 
Pat les) 2020 PAU 
174 
18.4 18.4 10 
14.5 14.6 105 
16.2 M70 44 
15.8 16.4 24 
23.9 23.8 28 
le, Zilad) 26 
22.8 22.5 5 
28.0 27.7 23 
265 


TOTALS 


No. 4 Offshore Fishes from Florida 133 
TABLE 1 (Continued) 
No. 
Depth Salinity %o Temp. °C of Fish 
Station Date No. of Tows (HE) Surface Bottom Surface Bottom Taken 
7 Nov. 0 0 
Dee. 21, 1962 2 42 35.0 Bia )oAl 16.1 IL {i 
Jan. 16, 1963 1 50 35.8 36.2 Ge 16.6 9 
Feb. 24, 1963 re 50 34.5 34.6 16.0 16.2 4 
Mar. 20, 1963 il 42 34.4 Bae Doel ZOE Zio 
Apr. 18, 1963 1 48 36.9 36.9 20.4 19.3 14 
May 13, 1963 1 44 Bien 36.4 Dilez, Oso 0 
June 5,1963 0 0 
TOTALS 8 i 
8. Nov. 0 0 
Dee. 0 0) 
Jane Li, LIS i 70 36.8 3623 ee 183 33 
Feb. 25, 1963 il 84 35.4 SO 16.4 16.6 4 
Mar. 20, 1963 1 iz 34.8 34.7 22.4 18.3 0 
Apr.18, 1963 1 81 36.8 36.5 Z0RS 18.3 3 
May 14, 1963 1(dredge) 81 35.8 36.4 Zono 21.0 0 
June 6, 1963 0 0 
TOMAS 5 10 
9. Nov. 0 0 
Dee. 0 0 
Jan. 0 0 
Feb. 25, 1963 il 102 Soh 35.8 IO 17.6 i) 
Mar. 20,, 1963 1 100 36.1 36.0 Pilea, 16.2 0 
Apr. 18, 1963 0 108 36.5 Sileo 21.0 19.0 0 
May 14, 1963 1(dredge) 108 35.8 36.9 Drees Papa) @) 
June 6, 1963 Z 105 31.2 36.8 PAT AD Des 150 
TOTALS 5 159 
Total number of fish taken from all nine stations.............. 53 BOE 
ish) takenspriorato November 19 Gao. ee eee ee 43 
TOTAL Dowel 
ment layers. The surface layer was very base, including parchment worm tubes, 


lightweight and consisted of a brown, or- 
ganic, drifting material which was concen- 
trated in shallow depressions and between 
the crests of the bottom ripples. The primary 
sediment layer consisted of sand and bits of 
shell and coral which produced a silty cloud 
when disturbed and appeared to be of the 
same composition as, but more finely grained 
than, the analogous sediments of the first 
station. This primary sediment layer was 
about 50 mm thick and gradually graded 
into compact gray clay infused with par- 
ticles of shell. Approximately 600 sqaure 
yards were examined at the offshore edge of 
station 2. No fish were observed, but visi- 
bility was limited to about eight feet. The 
most abundant animal was an anemone, 
Anemonia sargassensis, which was attached 
to everything that offered a large enough 


shells, sticks and other organic debris. 


STADION 32227-43-N 82 45 WW 

This station is located offshore of St. 
Petersburg Beach about one mile west of the 
surf line and offshore of the Don-Ce-Sar 
building. Depths ranged from 12 to 19 feet, 
although the extreme variations from the 
mean of 16 feet were usually not frequent. 

This station was sampled most (thirteen 
15-minute trawls, one more than station 2) 
and produced the greatest number of fishes. 
Trawling operations were conducted parallel 
to the beach, and depth was consistent dur- 
ing each haul. Trawling was always smooth 
and no rock or other irregularities were de- 
tected by the net or fathometer. 


The topography of stations 2 and 3 are 
the same. These two stations represent the 


134 


same general habitat and are often grouped 
together in the analysis of data. 


STATION 4: 27°39N, 82°52°W 

This station is located about 234 miles due 
north of the entrance to the Egmont ship 
channel. Depths ranged from 27 to 33 feet 
and the mean depth was 30 feet. Little dif- 
ficulty was experienced in finding and trawl- 
ing this area. 

This station had a bottom type intermedi- 
ate to stations | and 2. Reef formations 
were present, but of such low relief that 
trawling was not hindered. Although visual 
examinations were not attempted, fathom- 
eter recordings and net production suggest 
that the general bottom configuration con- 
sisted of hard flat sediments with occasional 
low rocky reef areas and patches of shell. 


STATION =5527°397N 82° 56°30 WW 

This station is located approximately 5 
miles due west of station 4. It is most 
analogous to station 1, although it exhibits 
a greater extent of rugged limestone reef. 
Sampling was discontinued in June, 1962, 
because trawling was not feasible on the 
rugged bottom, and it is not part of our 
eight-month study. It is mentioned because 
it contributed a few specimens to our collec- 
tion before being discontinued. 

SEATION: G6: 27° 34457N) 82°51-Ww 

This station is located approximately 0.2 
miles due west of Buoy R-2, at the mouth 
of the Egmont Ship Channel, on an azimuth 
of 253° from the Egmont Key Lighthouse. 
Depths ranged from 27 to 32 feet with a 
mean of 30 feet. Difficulties were seldom 
encountered during trawling operations. This 
station is most analogous to station 4 in 
depth and bottom composition, although 
there seemed to be fewer and less extensive 
patches of low reef and shell. For our pur- 
poses, stations 4 and 6 represent the same 
general habitat. 

STATION -7: 27°35/N 82°56 W. 

This station is located about 1 mile due 
west of the sea buoy of the Egmont Ship 
Channel. Sampling at this station began in 
December, 1962, and continued through 
April, 1963. May and June samples were 
not taken because of lack of suitable bottom 
for trawling. Depths ranged from 42 to 52 
feet and the mean depth was 46 feet. Lo- 
cation was indefinite at these distant off- 


Tulane Studies in Zoology 


Vol. 12 


shore stations since visual reference points 
were either vague or absent. Depth and run- 
ning time due west of the sea buoy were the 
criteria for station identification. Gross error 
in locating station 7 was avoided since the 
sea buoy was nearby. 


Operational difficulties similar to those at 
station | were encountered. Depth varied 
during trawling to a greater extent at this 
station than at the others. Bottom contours 
recorded on the fathometer included slopes 
and reef formations. The physical descrip- 
tion of station 1 is generally applicable to 
station 7. 


STATION 8: 27°35'N: 832070 

This station is located about 20 miles due 
west of Egmont Key. Depth and running 
time from the Egmont channel sea buoy were 
the criteria for station location. This station 
was sampled once a month from January 
through May at depths ranging from 70 to 
84 feet, and averaging 77.4 feet. The bottom 
type of station 8 appears similar to that of 
station 7. 


STATION 9: 27°35°N.83 41s 

This station is located about 30 miles due 
west of Egmont Key. Depth and running 
time were also employed to locate this sta- 
tion each month. Samples were taken during 
four moaths. Depths ranged from 98 to 108 
feet and averaged 100 feet. The bottom type 
is basically similar to stations 1, 5, 7, and 8. 


TEMPERATURE AND SALINITY 


Salinity differences between stations dur- 
ing this eight-month period were not great 
enough to be considered significant. Surface 
salinities ranged from 31.2 “ec at station 1 
in February to 37.2 “« at station 9 in June. 
Bottom salinities ranged from 32.8 “%o at 
station | in March to 37.5 “eo at station 9 in 
April. There was a difference of only 
6.3 “ec between the highest and lowest re- 
corded salinity during the eight months of 
the study. The greatest range at any station, 
irrespective of surface or bottom reading, 
was 5.5 “%, at station 1 and the smallest 
range was 1.8 “%- at station 9. Salinity tended 
to gradually incrase from November to June 
and gradually increased and stabilized with 
depth. 

Temperatures were generally lowest dur- 
ing December, ranging from 12.4°C to 
16.1°C at stations 1 through 7. The highest 


No. 4 


temperatures were taken in June and ranged 
from 27.6°C to 28.4°C at stations 1 through 
6. The greatest range between surface and 
bottom (4.2°C) was recorded at station 9 
during June in 105 feet of water. At the 
shallow and mid-depth groups, stations 2 
and 3, and stations 1, 4, 6, and 7, average 
surface and bottom temperatures did not 
vary more than 1°C during any one month. 
Temperatures were lowest in December, 
January and February, and rose sharply about 
8°C in March. After a small drop in April, 
they rose steadily through June. Data are 
incomplete for stations 8 and 9, but the same 
general pattern of temperature change was 
present for surface temperatures. Bottom 
temperatures for this depth group did not 
fluctuate as rapidly as the shallow groups 
and lagged noticeably behind the surface 
readings during the spring temperature rise. 
All readings were taken at night. 


METHODS AND MATERIALS 


Trips were conducted on board chartered 
commercial fishing vessels. These vessels 
were all equipped with fathometers which 
were used in determining depth and finding 
trawlable areas. A 16-foot balloon trynet 
(otter trawl) was the basic gear used for the 
collection of shrimp and fish. Whiteleather 
(1948) stated that the balloon trawl is built 
to open high and full at the mouth allowing 
the net to take fish well off the bottom. Nets 
were constructed of tarred, number 15 Dura- 
cot twine tied at a 2-inch stretched mesh. 
The 3-foot cod end was constructed of 1-inch 
stretched mesh. The head rope or cork line 
included floats and measured 18 feet, and 
the foot rope or lead line measured 181 
feet. These were attached to 30 by 15 inch 
wooden otter doors. 

Hildebrand (1954) mentions that the fish- 
ing effort of otter trawls, measured in units 
of time per tow, is vague because the fish- 
ing characteristics of these nets have not 
been analyzed. However, some recent ar- 
ticles of analytical nature are based on ob- 
servations, measurements, and photographs 
of otter trawls in operation (Sand, 1959; de 
Boer, 1959; and Scharfe, 1959). It is still 
difficult to standardize otter trawl operations. 
Some variables that prevent units of time 
from being accepted as exact standards are, 
nonuniformity in rigging of the nets, vari- 
ation in net shapes, differences in weights 
affixed to the foot rope, speed and other 


Offshore Fishes from Florida 


variables of the vessels, and sweep of the net 
both empty and full. We kept our nets as 
standard as possible during the study to al- 
low a general comparison of effort on a unit 
of time basis. The foot rope was always 
weighted with chain rather than lead and 
whenever the net was changed due to loss 
or damage the same style of rigging was 
used. The net was always set on the surface 
off the stern and any fouling was cleared 
before the net was lowered. Evidences of 
proper operation were obtained through 
yields of large amounts of flora and fauna 
characteristic of the bottom habitat. 


On three occasions a steel dredge, 37 
inches long, 30 inches wide and 14 inches 
high with a 34-inch expanded metal liner 
was used when the bottom was too rugged 
to effectively use the trynet. The dredge 
was productive only at station 9, before the 
beginning of our eight-month study. This 
dredge sample yielded seven species of reef 
dwellers that were not taken at any other 
station. 


Temperatures were determined im situ 
with a Whitney Underwater Thermometer 
Model TC 10 (Whitney Underwater Instru- 
ments, Box 521, San Luis Obispo, Cali- 
fornia) and later in the study with an Elec- 
trodeless Induction Salinometer Model RS-5 
(Industrial Instruments Inc., 89 Commerce 
Road, Cedar Grove, Essex County, New 
Jersey). Before use of the salinometer, sa- 
linities were determined with calibrated sa- 
linometer bulbs (G. M. Manufacturing Com- 
pany, 12 East 12th Street, New York, New 
York) and the readings then corrected for 
temperature. 


Specimens were preserved in 10% forma- 
lin. A representative sample of each species 
was retained after counting and usually after 
measurement when large amounts of certain 
species were taken in a single trawl. All 
fishes retained from these collections are 
deposited in the collection of the Florida 
Board of Conservation Marine Laboratory. 


Fishes taken during the first 10 months 
of the offshore sampling program, when 
specimens were only casually collected for 
the laboratory's ichthyological reference col- 
lection, are also included in this account. 
These 43 fishes were taken with the same 
gear (15 by dredge and 28 by trynet) and 
at the same stations as those during the eight 
months of our study. Their inclusion supple- 


136 


Tulane Studies in Zoology 


TABLE 2 
Fishes taken in offshore waters of Pinellas Co., Florida 


Mola? 


Species 


Gymnura nicrura 
Harengula pensacolae 
Synodus intermedius 
Bagre marinus 
Galeichthys felis 
Urophycis floridanus 
Centropristes melanus 
Diplectrum formosum 
Ephinephelus morio 
Serranus subligarius 
Serranus pumilio 
Lutjanus synagris* 
Apogon alutus 
Apogon conklini 
Apogon 
pseudomaculatus* 
EFucinostomus gula 
Haemulon plumieri 
Orthopristis 
chrysopterus 
Bairdiella chrysura 
Cynoscion arenarius 
Cynoscion nebulosus 
Equetus lanceolatus 
Leiostomus xanthurus 
Menticirrhus 
americanus 
Menticirrhus littoralis 
Micropogon undulatus 
Calamus artifrons 
Diplodus holbrooki 
Lagodon rhomboides 
Chaetodipterus faber 
Chromis enchrysurus* 
Toglossus calliurus 
Garmannia macrodon 
Scorpaena brasiliensis 
Scorpaena calcarata* 
Bellator militaris 
Prionotus pectoralis 
Prionotus roseus* 
Prionotus scitulus 
latifrons 
Prionotus tribulus 
crassiceps 
Astoscopus y-graecun 
Blennius marmoreus 
Ophidion beani* 
Otophidion grayi* 
Ophidion holbrooki 
Ophidion welshi* 
Lepophidium jeannae* 
Peprilus alepidotus 
Ancylopsetta 
quadrocellata* 
Bothus ocellatuso 
Bothus ocellatus* 
Citharichthys 
macrops* 
Cyclopsetta fimbriata* 


byeto Se 
Stations 
2 


J Pwor| | | 


> | 


H 


approximate depths 


25’ to 45’ 


Stations 
5 6 


~ 


Tb! to Ob, 
Stations 
8 9 


Total 


il! _ 


| 
bo 


| ww 


bo 
ees) 


| 
}r}]a owl 


I 
iw 
| eA] 


| 
| 


= | 


Bel ele] wl] 


> 


es 


be OS bet 
Boe BDO ReN RR Ww Wr Oo ww 


vo OO 
el] 
HCO 


i 


—_ bob o1 OR ONHeNrF OO 


No. 4 Offshore Fishes from Florida 137 
TABLE 2 (Continued) 
approximate depths 
15) tome? 254 tora? om towlone 
Stations Stations Stations Total 
2 3 1 4 5 If 8 9 
Etropus crossotus 
atlanticus Wa 114k — 19 — 21 — — — 65 
Etropus rimosus* = = = SS sY/ 57 
Paralichthys albigutta 8 = = = = it 3 = = 1 
Syacium papilloswm* — 2 - - 8 -- — 67 ie 
Achirus lineatus* _ 1 — = 1 
Symphurus 
diomedianus* — — — — 3 3 
Symphurus plagiusa ao) 28 120 — 26 2, 3 - ale 
Gobiesox strumosus - ~ os 1 
Alutera schoepfi ~ 2 — - = 2 
Stephanolepis hispidus _ - 4 5 
Lactophrys 
quadricornis 2 3 3 - = 1 -- - = 9 
Sphaeroides nephelus il _ = — 1 
Chilomycterus 
schoepfi 1 it — — i 
Diodon holocanthus* 2 = — = — —- = - = 2 
Opsanus pardus ~ ~ 1 — — 1 _— — = 2, 
Porichthys 
porosissimus it 6 - 4 2 4 ~ 1 1 iy) 
Antennarius ocellatus — — _ - 1 - Byres 4 
Ogcocephalus cubifrons 1 — — — — il 
Halieutichthys 
aculeatus* _ - _ - ~ — - 7 7 
TOTALS 645 933 AT emilee 3 266 57 ie ee Pray [fate 
EFFORT 
(Number of 15- 
minute trawls 
during 8-month 
survey period) 12 ale Galil — 10 7 5 5 
NUMBER OF 
SPECIES: 
by depth divisions 39 41 30 
by station 30. 30 Si lis 7 Page BU 223 


* Not reported from the Gulf of Mexico in the area of Tampa Bay by Springer and 
Woodburn (1960) during the period of their study, but recorded by them from Tampa 


Bay, Old Tampa Bay, or Boca Ciega Bay. 


** Including 43 fishes taken prior to November, 1962. 
*** Wishes taken by dredge June 5, 1962 (37.1 %o, 21.8°C) 


ments the species taken during that period, 
although their data do not contribute to our 
species analyses. 

Measurments were made on a standard 
l-meter fish measuring board, usually after 
the fishes had been in 10% formalin for 
several days. In instances when the catch 
was extensive, measurements were made 
aboard the collection vessel. Fork length 
(FL) was taken on fishes with forked tails 
and total length (TL) was taken on fishes 
with lunate or truncate tails. Standard length 
(SL) is given wherever possible to facilitate 
comparison with other studies, but it was 


not taken consistently since it was not con- 
sidered an accurate field measurement on 
small fishes. 

Tables and graphs are based on either TL 
or FL, although the approximate SL for each 
3 mm grouping is also listed. These standard 
lengths were obtained from fishes that were 
retained and do not represent the entire 
number collected; thus they are considered 
approximate, but accurate enough for com- 
parative purposes. 


SYSTEMATIC ACCOUNT 


Nomenclature and phyletic family listing 
follow the presentation of the American 


138 


Fisheries Society (Bailey et al., 1960). Only 
bottom temperatures are mentioned in the 
text unless otherwise stated. Figure 2 iden- 
tifies the various graph symbols used in Fig- 
ures 3 through 5. The 12 species of fishes 
that were most numerous (89.4% of the 
total catch) are discussed individually, and 
Table 2 summarizes the data for all species. 


Diplectrum formosum (Linnaeus ) , 


Sand Perch 

This species, unlike Centropristes melanus 
which commonly dwells on the reef areas, is 
usually found on the sandy interstices be- 
tween reef formations. We collected 34 in- 
dividuals, 99 to 229 mm TL, distributed 
through every month and every station ex- 
cept station 8. The largest collection, five 
individuals, occurred in June at station 9. 
Stations 4 and 6 yielded 56% of our speci- 
mens of sand perch. The only evident dis- 
tributional pattern in regard to month or 
station was the occurrence of the largest fish 
on the stations farthest offshore, 7 and 9. 
Our data agree with the findings of Longley 
and Hildebrand (1941), Reid (1954) and 
Hildebrand (1955) who reported D. for- 
mosum from deep, sandy bottoms. This spe- 
cies is usually evident in the catches of party 
boats and during SCUBA diving excursions. 


Orthopristis chrysopterus (Linnaeus ), 
Pigfish 

This species was taken during every month 
and was the second most numerous fish, 376 
individuals, in our total catch. Springer and 
Woodburn (1960) presented an extensive 
analysis of the occurrence of young pigfish 
in Tampa Bay during the course of their 
study. Our data (Figure 2) supplement 
theirs by extending the area of investigation 
into the offshore waters. The months of our 
largest collections were December through 
March. These months are the period of scar- 
city for species on the inshore grounds as 
both Springer and Woodburn (op. cit.) and 
Reid (1954) indicated. The size range of 
our November through January collections 
from stations 2 and 3 corresponds to the 
October through December collections of 
Reid (op. cit.) and Springer and Woodburn 
(op. cit.). Our data indicate that these fish, 
which apparently move to offshore locations, 
remain offshore and undergo more rapid 
growth with the advent of warmer temper- 


Tulane Studies in Zoology 


Volegi2 
atures. The lowest temperature at which 
this species was taken was 12.5°C. 


chrysopterus 1s common in the more 
northern and more saline coastal environ- 
ments of the Gulf. As Springer and Wood- 
burn mentioned, its abundance in shallower 
coastal waters decreases in southern Florida. 
Hildebrand (1955) commented that this 
species was common in 6 to 10 fathoms on 
the pink shrimp grounds in the Gulf of 
Campeche during February and July, and 
Tabb and Manning (1961) classified them 
as abundant in Joe Kemp-Conchie Channel 
during the cold winter of 1957-58. The pig- 
fish may be more abundant offshore than 
inshore in the southern regions of the Gulf 
of Mexico. 


Bairdiella chrysura (Lacepede ) , 
Silver perch 


This species was the third most numerous, 
349 individuals, in our total catch. With the 
exception of four large specimens taken in 
deep waters, all silver perch were collected 
from our shallowest depth range, stations 2 
and 3. Station 3, the sampling area nearest 
to Tampa Bay, produced 71.8°% of the total 
collected. B. chrysura was present in our 
collections during every month except May, 
but was poorly represented during April and 
February. Springer and Woodburn (1960) 
did not take this species in April and took 
only the very young during May; however, 
their gear was not effective for the larger 
fish. Spawning for this species probably 
takes place about that time as Springer and 
Woodburn (1960), Reid (1954) and Gun- 
ter (1963) took the first young of the year 
in May. 

We assume that the paucity of specimens 
in our collections for April and May is due 
to a spawning migration to inshore waters. 
Springer and Woodburn (1960) concurred 
with Gunter (1945) that spawning takes 
place in the bays. Our June collection ts in- 
dicative of a return to the Gulf after spawn- 
ing. Four individuals from the June collec- 
tion were examined; two were gravid females 
(160 and 173 mm TL) with well-developed 
ova, and two were males (153 and 156 mm 
TL) in gross appearance, although sperm 
were not observed. This indicates that 
spawning may continue into June in the 
Tampa Bay area. The length and time of the 
spawning season may vary with annual me- 


STATION | 


LJ 
Se STATION 2 and 3 


Figure 2. 


teorological conditions. Tabb and Manning 
(1961) collected running ripe silver perch 
during late February in the Florida Bay area, 
and Joseph and Yerger (1956) mentioned 
collecting young in June and September. 
Gunter (1945) reported that B. chrysura 
spawns during rising temperatures and 
moves into the open Gulf waters in fall and 
winter. 

Our data (Figure 3) illustrate that the 
November and the large December collec- 
tions approximate the size range of the speci- 
mens that both Springer and Woodburn 
(1960) and Reid (1954) took during those 
months. Growth in this first year class ap- 
pears to speed up as the water warms. Gun- 
ter (1938) suggested that the life history of 
this species is short and implied that sexual 


Offshore Fishes from Florida 


STATION 7 


Monthly length-frequeney dis- tributions of Orthopristis chrysopterus. 


PLUS 15 
NOT 
MEASURED 


JAN, 


INCLUDING 


FEB. ONE 226mm 


STATION 4 and 6 mi STATION 8 


STATION 9 


maturity may be achieved during the first 
year. The normal life history probably spans 
only two annual cycles. 


Leiostomus xanthurus (Lacepede) , Spot 


A total of 35 spot was collected from De- 
cember through June. All of these, with the 
exception of three from station 6, were 
taken at stations 2 and 3. The collections 
for December and June represent 77.1% of 
total spot taken. Our specimens ranged in 
size from 125 to 205 mm TL. There were 
no tendencies toward monthly increments or 
regressions in size evident in our samples. 
L. xanthurus (particularly juveniles) is very 
abundant in coastal areas from Tampa Bay 
northward along the Gulf Coast. Bailey et al 
(1954) and Gunter (1963) recorded the 


oO 
© 
fa) 
rm 
= 
UD 
= 


Tulane Studies in Zoology 


not 


Jan. plus i2 


N.-33 


March 


N.- 57 


plus 61 not 


measured 


Vole 


Figure 3. Monthly length-frequency distributions of Bairdiella chryssura. Graph legend as in Figure 2. 


No. 4 


young of this species from freshwater habi- 
tats, and Springer and Woodburn (1960), 
Kilby (1955), Joseph and Yerger (1956), 
and Miles (1951) all listed the spot as 
abundant in shallow waters. There is an ap- 
parent movement of young spot from in- 
shore to offshore waters as they grow, and 
Springer and Woodburn (op. cit.) postulated 
a late winter spawning and an offshore mi- 
gration in late summer for the Tampa Bay 
area. Spawning occurs primarily in Decem- 
ber and January along the South Carolina 
coast with two and three-year-olds as the 
principle spawners (Dawson, 1958). Gun- 
ter (1938) suggested that the life cycle of 
the spot is short. Our findings of only a 
rather small, randomly sized population of 
adult fish in the offshore waters during and 
several months after the peak of spawning 
agree with the findings of the above authors. 


Menticurhus americanus (Linnaeus), 
Southern kingfish 


This whiting was taken every month ex- 
cept November and May. Fifty-six percent 
of our 70 specimens were taken during 
December. All but seven individuals were 
collected at stations 2 and 3. Sizes ranged 
from 132 to 281 mm TL. The smallest fish 
was taken in January and the largest in April. 
As with the spot, no monthly size incre- 
ments or regressions were evident. The gon- 
ads of specimens collected in February were 
examined, but were not ripe and sex was 
not distinguishable. One female (280 mm 
TL, station 2) was found among the four 
fish examined from the March collection. 
The other three (208 to 214 mm TL, sta- 
tion 4) appeared to be males. One female 
(216 mm TL) and one apparent male (214 
mm TL) occurred in the April collection at 
station 3, and one female (186 mm TL) 
and an apparent male (191 mm TL) from 
station 2 comprised the June collection. All 
females had well-developed ova. 

M. americanus is uncommon in waters of 
low salinity and according to Hildebrand 
(1954, 1955) and Miles (1951) it is the 
common whiting of the open Gulf. Our data 
indicate that the adults are commonest in the 
open Gulf during the winter and that spawn- 
ing occurs from March to at least June. This 
agrees with Springer and Woodburn (1960) 
who suggested a May and June spawning at 
the time of their study, and Gunter (1945) 


Offshore Fishes from Florida 


141 


who mentioned that this whiting leaves the 
bays in the winter. 


Lagodon rhomboides (Linnaeus ), Pinfish 


The pinfish is one of the most abundant 
and characteristic fishes along the coastal 
region of the eastern and northeastern Gulf 
of Mexico. This species was taken during 
every month except November and, although 
it varied greatly in monthly abundance, it 
was the most numerous fish (590. individ- 
uals) in our total catch. Our data (Figure 
4) will be discussed only where it adds to 
the findings of Caldwell (1957) and Springer 
and Woodburn (1960). 


Pinfish first appeared in our collections 
in December. This December collection was 
the largest single collection of any species 
at any time during our study. The 261 in- 
dividuals were taken at both the shallow 
and mid-depth stations with a strong pat- 
tern of size distribution according to depth 
evident. The size range of the smaller fishes 
(79 to 109 mm TL) from the shallower 
stations, 2 and 3, closely approximates the 
size ranges of the first year class collected 
by Springer and Woodburn (1960), Cald- 
well (1957) and to some extent Reid (1954). 
We believe this influx of pinfish at the 
shallower stations in December to be the 
migration of the first year class into the off- 
shore waters as Caldwell postulated an off- 
shore migration in cold weather, and Spring- 
er and Woodburn’s first year class diminishes 
in average size and number inshore after 
December. The size range of the fishes from 
the mid-depth stations 1, 4, 6, and 7 indi- 
cates the presence of the second year class 
in the deeper waters. Spawning is thought 
to take place offshore in the Gulf during the 
winter months and our findings place Cald- 
well’s first spawners, the second year class, in 
about 6 fathoms at this time. This second 
year class is no longer evident in our sam- 
pling after December, but few pinfish were 
taken in the following two months. We can- 
not adequately explain the sharp increase in 
numbers each third month of our study. No 
other species reflected this pattern of abun- 
dance. Growth apparently speeds up as the 
water warms since the size range of our 
June collection approaches those taken at 
the mid-depth stations in December. Dur- 
ing the March collection, 149 pinfish were 
discarded from the catch at station 3 before 


142 Tulane Studies in Zoology Vol. 12 
= OM ©ONNMO— 
OMOMNMO—-TROMODNHO—-TROM OP AW O-Th 
Se FF NN 0 COKEK RODD OO OO ——=N ANN ONS wees 
o-tsrKOmM in © OMmon _~tROMODNNO—-TROMO 
ie RRR ODDDDDOOCOLL2aANAMMMMYTTTNMNOO FL 


_ NS 3 May ; 


a N- 48 June 


N- 87 March 
plus 149 


not measured 


-12 April 


Figure 4. Monthly length-frequency distributions of Lagodon rhomboides. Graph leg- 


end as in Figure 2. 


measurement. These fish were within the 
size range of the 87 that were measured. 


Prionotus scitulus latifrons (Ginsburg ), 
Leopard searobin 

A total of 265 leopard searobins was col- 
lected. They were taken during every month 
with little variation in abundance. The larg- 
est collection occurred in March at the time 
of the strongest recruitment of young fish 
into our trawl catches. This subspecies 1s 
reported by Hildebrand (1955) as one of 
the most common and most characteristic 
fishes on the pink shrimp grounds off Cam- 
peche, and Springer and Bullis (1956) re- 
corded this species from 14 stations in the 
Gulf. Our data (Figure 5) also indicate that 


this species strongly favors the offshore en- 
vironment. Table 3 shows 69.7% of our 
specimens were collected at mid-depth sta- 
tions. Springer and Woodburn (1960), Reid 
(1954) and Tabb and Manning (1961) did 
not take the leopard searobin in abundance 
during their studies, and the latter two 
papers report its occurrence adjacent to rela- 
tively deeper waters. 

Our gear did not catch fishes smaller than 
50 mm SL so the presence of fishes under 
this length would not be detected. Small in- 
dividuals appeared in our trawls of the mid- 
depth stations during February and March 
and were present through June. Fish from 
the February through June collections were 
examined for sexual development and _fe- 


Offshore Fishes from Florida 143 


9 


th-frequency distributions of Prionotus scitul us latifrons. Graph legend as in Figure 


Monthly leng 


Figure 5. 


144 Tulane Studies in Zoology Vol. 12 
TABLE 3 
Percentages of fishes taken at each depth range for the 12 most numerous 
species in the catch 
depths 
Total 15’ - 18’ 25’ - 45’ 75’ - 105’ 

Species Collected Percent Percent Percent 
Bairdiella chrysura 349 98.9 a2, 0 
Leostomus xanthurus 35 91.4 8.6 0 
Menticirrhus americanus 70 90.0 10.0 0 
Lagodon rhomboides 590 88.1 Leg 0 
Prionotus tribulus crassiseps 28 85.7 10.1 3.6 
Orthopristis chrysopterus 376 82.2 17.5 3 
Symphurus plagiusa Tal 54.0 43.4 Pall 
Etropus crossotus atlanticus 65 38.5 61.5 0 
Prionotus scitulus latifrons 265 23-3 falend 0 
Diplectrum formosum 34 14.7 70.6 14.7 
Syacium papillosum hal 2.6 10.4 87.1 
Etropus rimosus 57 0 0 100 
Total number of fishes 

taken at all depths 2317 1578 548 191 
Percentage of total 

number of fishes 68.1 Zou 8.2 
Number of trawls 

producing fish 66 PAS By 9 
Percentage of the 

total effort 13.6 


a9 48.4 


males with well-developed ova were observed 
in every month during this period. These 
females varied from 141 to 180 mm TL and 
were taken at both shallow and mid-depth 
ranges. The fish examined in February had 
well-developed ova; those fish examined 
from the March through May collections ap- 
peared to be nearing spawning condition; 
those examined from the June collection 
would extrude eggs upon pressure. Reid 
(1954) collected young fish (20 to 25 mm 
SL) in June, August, October, January, and 
May, a female in November with “slight 
ovarian development’, and a male in De- 
cember which “appeared to be near breeding 
condition.” Springer and Woodburn (1960) 
collected small fish in every month except 
December, 1957 and August, 1958. The in- 
flux of small specimens in our mid-depth 
trawls of February and March, apparent 
breeding conditions of adults from Decem- 
ber to at least June, and appearance of young 
fish at various times throughout the year 1n- 
dicate an extensive spawning season. 


Prionotus tribulus crassiceps (Ginsburg ), 
Bighead searobin 


Twenty-eight bighead searobins were taken, 
27 during the eight months of sampling and 
one (233 mm TL) at station 6 in March of 
1962. Two additional large fish were taken, 
one 228 mm TL at station 6 in November 


and one 247 mm TL at station 8 in April. 
The remaining 25 specimens were collected 
at stations 2 and 3 every month from Febru- 
ary through June. These fish ranged in size 
from 69 to 113 mm TL. A trend toward in- 
creasing size was noted for each monthly 
collection. 

Several authors, Miles (1951), Joseph and 
Yerger (1954), and Tabb and Manning 
(1961) reported this species as commonly 
occurring at inshore locations, and Hilde- 
brand (1955) considered it to be more abun- 
dant inshore than offshore. Our data, al- 
though limited, agree with this view since 
85.7% of our specimens were taken at the 
shallowest stations. 

Joseph and Yerger (1954) postulated a 
late summer and fall spawning and Gunter 
(1963) suggested a late fall and early winter 
spawning for P. tribulus tribulus. Hilde- 
brand (1954) found a nearly ripe female 
on the Obregon shrimp grounds (Texas) in 
early August. Springer and Woodburn 
(1960) found young fish from October 
through February in the Tampa Bay area. 
We first found small individuals of P. trzbu- 
lus at the same time of the appearance of 
small P. scitulus, February and March. These 
observations indicate that some spawning 
takes place in early fall, although spawning 
activity may extend over a greater period. 


No. 4 


Etropus crossotus atlanticus CRarn)e 
Fringed flounder 


Fringed flounder were taken during every 
month for a total catch of 65 individuals. 
Total lengths ranged from 76 mm to 169 
mm with the smallest fish taken in Novem- 
ber and the largest in April. The June col- 
lection, 22 specimens, represented 33.8% 
of the total catch of this species. Ripe fe- 
males were found every month from March 
through June and varied from 111 to 169 
mm TL. The ovaries of fish from the June 
collection were turgid with eggs. Our data 
did not reveal any pattern of growth. 

E. crossotus appears to be generally more 
common offshore than inshore. Hildebrand 
(1954, 1955) found it quite common in 
depths less than 17 fathoms offshore of 
Texas and Louisiana and on the Campeche 
Banks. Springer and Woodburn (1960) and 
Tabb and Manning collected very few, al- 
though it was common in the inshore collec- 
tions of Reid (1954), Joseph and Yerger 
(1956), Miles (1951) and Gunter (1938). 
The center of abundance of this fish appears 
to move farther offshore in the more south- 
er areas of the Gulf of Mexico. Reid 
(1954) found two young fish, 23 and 25 
mm SL, in June and October, respectively, 
and postulated an “extended breeding sea- 
son during spring and summer.” Our data 
indicate that spawning takes place offshore 
from March until at least June, thus agreeing 
with Reid’s findings. 


Etropus rimosus, (Goode and Bean), 
Gray flounder 


Fifty-seven gray founders were collected, 
all during June and only at station 9. Total 
length ranged from 101 to 133 mm and 
were arranged in two well-defined group- 
ings which were probably composed of dif- 
ferent sexes. All the fish (10 individuals) 
examined between 101 and 118 mm TL, 
were ripe females; and all fish (5 individ- 
uals) examined between 124 and 133 mm 
TL appeared to be male, although no milt 
was observed. No other species in our col- 
lections, except Syacium papillosum, dis- 
played this sexual dimorphism of size. These 
data indicate an early summer spawning for 
this species. 

E. rimosus is quite distinct from E. 
crossotus when comparative material is avail- 
able. Our specimens agree with the descrip- 
tion given by Longley and Hildebrand 


Offshore Fishes from Florida 


145 


(1941). The snout of both sexes is covered 
with strongly ctenoid scales, and the pectoral 
fin on the ocular side is longer and larger 
than that of E. crossotws and has three to 
four horizontal, dark narrow bands which 
Longley and Hildebrand did not mention. 
The dark blotch on the lateral line just in 
advance of the dorsal and anal fin termina- 
tions varies from dark and well-defined to 
rather obscure. E. rzmosus has three dark 
blotches equally spaced along the lateral line, 
although the posterior blotch, about the size 
of the eye, is largest and most distinct. The 
scales of E. ramosus are strongly ctenoid on 
the ocular side and mildly ctenoid on the 
blind side, whereas scales of E. crossotus are 
mildly ctenoid on the ocular side and smooth 
on the blind side. 

Springer and Bullis (1956) and Hilde- 
brand (1955) did not encounter this spe- 
cies, but Joseph and Yerger (1956) recorded 
it offshore of Alligator Harbor, and Briggs 
(1958) reported it from the southern At- 
lantic coast and the northeastern Gulf of 
Mexico. Evidently, E. rimosus is fairly un- 
common and restricted to the offshore waters 
of the eastern Gulf. 


Syacium papillosum (Linnaeus ), 
Dusky flounder 


Seventy-seven specimens were collected, 
and only 10 of these came from. stations 
inshore of station 9. S. papillosum was taken 
in every month except March and May. The 
largest collection of 59 individuals came 
from station 9 in June, and the smallest and 
largest fish (76 and 229 mm TL) were in- 
cluded in this sample. About half of this 
collection was examined for sexual develop- 
ment, and 14 ripe fish were found. The 
eight females were mildly distended with roe 
and varied from 137 to 175 mm TL. The six 
males strongly exhibited the sexual dimor- 
phic traits characteristic of the males of this 
species, 7.e., a cinereous blind side, two par- 
allel blue lines between the right eye and 
the snout area, and long filamentous exten- 
sions on the dorsal rays of the pectoral fin 
of the ocular side. Several smaller males 
with their external sexual characters not 
fully developed were also included in the 
collection. These data indicate an early sum- 
mer spawning, although activity may take 
place over an extended period. No growth 


data were available through our collections. 
Longley and Hildebrand (1941), Hildebrand 


146 


(1955), and Joseph and Yerger (1956) all 
reported S$. papillosum from the offshore 
waters, and Springer and Bullis (1956) re- 
ported it from 36 Oregon stations in the 
Gulf of Mexico. 


Symphurus plagiusa (Linnaeus ) , 
Blackcheek tonguefish 


The blackcheek tonguefish was present 
every month, although it was rather scarce 
from December through February. A total 
of 113 specimens was taken from stations 1 
through 8, but 54.09% came from the shal- 
lowest stations. Ginsburg (1951) considers 
it an inshore species since it ranges to only 
14 fathoms. Our gear was selective for the 
larger individuals since most of the fish taken 
(124 to 174 mm TL) were wedged in the 
mesh of the net. Ripe females were found 
in the March through June collections and 
varied from 145 to 168 mm TL. Spawning 
appeared to occur in June; some of the fe- 
males examined from that month had flaccid 
ovaries with many free eggs. 

S. plagiusa is common in the offshore 
waters in many areas of the Gulf (Hilde- 
brand, 1954, 1955; Gunter, 1945; Miles, 
1951; and Joseph and Yerger, 1956) and the 
young are also occasionally taken in salini- 
ties below 7 “%o (Springer and Woodburn, 
1960; Gunter, 1963). Hildebrand and 
Cable (1930) postulated a May through 
October spawning period based on the ap- 
pearance of juveniles off North Carolina. 
We agree with this concept of an extended 
spawning period since Gunter (1945) took 
a ripe female in April; Joseph and Yerger 

(1956) found young fish in July; Tabb and 
tea (1961) reported taking small speci- 
mens of 20 mm (total length, we presume ) 
in March and September; Springer and 
Woodburn (1960) and Gunter (1963) re- 
ported their smallest tonguefish, 19 mm SL 
and 29 mm TL respectively, in October; 
and Springer and McErlean (1962) found 
26 and 21 mm SL tonguefish in January and 
February respectively. 

Table 2 is both a summary and analysis 
of each species present in our collections. 
We do not feel the need to comment on each 
species taken since the sparsity of our data 
in most cases would allow only occurrence 
to be mentioned. The stations are arranged 
by depth, shallowest to deepest. A summary 
of the effort expended and the number of 
species taken at each station and depth range 


Tulane Studies in Zoology 


Vol. 12 


is included at the end of the table. The 43 
fishes taken prior to the eight months of 
the study are included in this table, and since 
they represent only 1.9% of the total fishes 
taken, they are not distinguished unless they 
were part of a dredge collection. Springer 
and Woodburn (1960) discussed distribu- 
tion and relative abundance of the species 
they observed in the Tampa Bay area. In 
Table 2, we have distinguished the species 
collected during our study that were not re- 
ported from the Gulf of Mexico by Springer 


and Woodburn (1960) in their Tables 20 . 


or 22. Some of these fish were reported 
from the bay environs, but not the Gulf. 


Only three specimens of Urophycis flori- 
danus were taken, two in February at station 
2 (92 mm SL) and at station 7 (114 mm 
SL) and one in March at station 4 (92 mm 
SL). According to Gunter (1945), Reid 
(1954) and Springer and Woodburn (1960), 
this species is found on the inshore areas 
during January through April. These in- 
dividuals are generally juveniles as were 
our specimens. 

Eight specimens of Lutjanus synagris (05 
to 110 mm SL) were taken during Novem- 
ber, three at station 2, four at station 3, and 
one at station 6. Another individual taken 
on September 13, 1962 (87 mm SL, 34.6 %o, 
30.6°C) at station 2 augments our collec- 
tion to nine fish. Large individuals of this 
species are occasionally taken by party boats 
fishing the deeper waters during the sum- 
mer, and Hildebrand (1955) reported L. 
synagris to occur frequently on the Cam- 
peche Banks between 6 and 16 fathoms. 
Juveniles appear to move inshore during the 
fall of the year. Reid (1954), Springer and 
Woodburn (1960) and Tabb and Manning 
(1961) found L. synagris to be either pres- 
ent or abundant only during September to 
December. 


Menticirrhus littoralis was collected only 
three times during our study. Two speci- 
mens, 160 and 165 mm TL, were taken in 
November at station 2, and one near-ripe 
female, 260 mm TL, was taken at station 3 
in March. Springer and Woodburn (1960) 
found this species abundant in the summer 
at their beach station only one mile distant 
from our collection site. These fish, in their 
larger size ranges up to 169 mm SL, would 
have been more frequent in our trawls if 
they were present at the nearshore stations. 


No. 4 


Springer and Woodburn’s data indicate a 
spring spawning, probably May, and our data 
corroborate theirs. The winter habitat of 
M. littoralis remains unknown. 


One specimen of Bellator militaris, 56 mm 
TL, was taken at station 3 in June. It was 
evidently a stray from deeper waters since 
this species is common in collections from 
100 fathoms offshore of the lower west 


coast of Florida. 


Two species of Bothus were taken, B. ocel- 
latus and one recently recognized, but not 
named, which was identified by Dr. C. R. 
Robins. These fish were taken at both mid- 
depth and deep stations. Springer and Mc- 
Erlean (1962) probably took both species 
at their shallow water station in the Florida 
Keys, and Tabb and Manning (1961) did 
not record these species from the more in- 
shore area of Florida Bay. Hildebrand (1955) 
reported B. ocellatus as the commonest flat- 
fish on the Campeche Bank in 6 to 10 fath- 
oms in February, and common in 13 to 16 
fathoms in July. 


Citharichthys macrops was reported as very 
common on the Campeche Bank by Hilde- 
brand (1955), but Longley and Hildebrand 
(1941) only reported two specimens. This 
species was not rare at our mid-depth and 
deep stations. Two ripe females, 144 and 
205 mm TL, were taken in March at stations 
7 and 9. Spawning probably takes place in 
the spring. 

One specimen of Gobiesox strumosus, 05 
mm TL, was taken in a dredge sample at 
station 9 on June 5, 1962 (37.1 %o, 21.8°C). 
The collection of this individual offers a con- 
trast to Springer and Woodburn’s (1960) 
statement that this species is “strictly an 
inshore shallow water form.” G. strumosus 
was also reported from the Gulf by Springer 
and Bullis (1956) who recorded it at 16 and 
25 fathoms. 

One large specimen of Ogcocephalus cubi- 
frons, 267 mm TL, was taken at station 2 in 
June. Our identification is based on a simi- 
larity with the O. cubifrons of Longley and 
Hildebrand (1941) and the opinion of 
Springer and Woodburn (1960) that the 
common species of the Tampa Bay area is 
this form. 

Dr. C. R. Robins kindly identified the 
Ophidiidae, Bothus, and Chromis enchrysu- 
rus; and Dr. Ernest Lachner graciously iden- 
tified the Apogonidae for us. All other iden- 


Offshore Fishes from Florida 


147 


tifications are the responsibility of one of 
us (Moe). 


DEPTH RELATIONSHIPS 


It was not possible to ascertain the exact 
habitat from which each species was taken 
since our nets moved over a variety of bot- 
tom types and probably sampled several dif- 
ferent biotopes during each haul. As a re- 
sult, our analysis is restricted to the depth 
relationships of the 12 most numerous fishes 
in the total catch. Table 3 lists these fishes 
in order of their relative abundance at the 
shallowest stations. The depth preferences 
of these fish, within the limits of this study, 
are evident in Table 3. 

The shallowest stations 2 and 3, produced 
the greatest number of fishes (68.1% of the 
total catch), although only 37.9% of the ef- 
fective effort (trawls that took fish) was 
expended at these stations. The mid-depth 
stations received 48.4% of the effective ef- 
fort and produced only 23.7% of the total 
catch. Our deep range, stations 8 and 9, 
was better balanced with 13.6% of the ef- 
fective effort producing 8.2% of the total 
catch. The mid-depth stations had their own 
characteristic fishes and also exhibited fringe 
populations of typical inshore and offshore 
species. Although the analysis is very gen- 
eral, it demonstrates the distinctness of the 
bottom fishes at various depths offshore of 
Pinellas County. 

Gunter (1945, 1950 and 1961) showed 
that salinity can be correlated with size in 
marine fishes, although a direct relationship 
may not exist. Larger fish are generally 
found in higher saline waters, and conse- 
quently are found deeper and farther off- 
shore than smaller fish. Our data consist- 
ently exhibit the larger fish of most species 
occurring at the deeper stations. The salinity 
differential was probably too small to be 
significant in this distributional pattern. 
Depth then becomes one of the most obvious 
variables with a direct correlation to increas- 
ing size. 


APPENDIX 


During the course of this study, 15 species 
of fish were taken that have not been re- 
ported from the Tampa Bay area. An ad- 
ditional 27 species new to the area were 
taken in incidental collections since the pub- 
lication of the above papers, and these rec- 
ords are also listed here. Springer and Wood- 


148 


burn (1960) and Springer (1961) recorded 
271 species of fishes from the waters of the 
Tampa Bay area. The number of species of 
fishes now known from the Tampa Bay area 
is 312. The specimens on which the fol- 
lowing records are based are deposited in 
the laboratory reference collection unless 
noted otherwise. 

Carcharodon carcharias (Linnaeus). On 
February 10, 1965, a female white shark 11 
ft. 10 in. total length was taken by the col- 
lecting crew of the Aquatarium with a 12 
in. stretched mesh porpoise net. The capture 
occurred in four feet of water on a sand bar 
just offshore of Bunce’s Pass at the north 
end of Mullet Key. The animal was photo- 
graphed and discarded. There are two un- 
confirmed reports of white shark taken in 
the Tampa Bay area during the previous year. 


Carcharinus obscurus (LeSueur). Springer 
(1961) reported two large specimens of 
Eulamia (Carcharinus) floridana stranded on 
a sand bar in Boca Ciega Bay on December 
24 and 25, 1960. Garrick, et. al. (1964) 
demonstrated that these specimens were in- 
correctly identified and are actually C. ob- 
scurus, not previously reported from the 
Tampa Bay area by that name. Carcharinus 
falciformis (C. floridana) has not been taken 
in the Tampa Bay area. 


Raja eglanterta Bosc. Two males, 490 and 
540 mm TL, were taken with hook and line 
about 10 miles offshore of Clearwater Beach 
on February 2, 1963. Depth was 50 feet and 
bottom salinity and temperature were 33.8 “%o 
and 14.9°C. Since that time, three other 
specimens of the clearnose skate, two females 
and a male, have been taken from offshore 
waters in the Tampa Bay area. 


Raja texana Chandler. One female, 378 
mm TL, was taken in a large trawl from the 
R/V Hernan Cortez on December 21, 1964, 
at approximately 27°23’N, 83°20’W in 120 
ft. of water. This specimen was taken in the 
same trawl haul as Bregmaceros atlanticus. 
Although the location is just suoth of the 
defined Tampa Bay area, these records are 
considered applicable since both species have 
been reported north and south of this region 
(Springer and Bullis, 1956). 

Sardinella brasiliensis (Steindachner). One 
individual, 179 mm SL, was found in a box 
of frozen bait obtained from the Pinellas 
Seafood Company. The fish was captured 
in a commercial shrimp trawl in March of 


Tulane Studies in Zoology 


Vol. 12 


1964 about 8 miles offshore of Pass-a-Grille, 
Florida. 

Saurida brastliensis Norman. Two speci- 
mens, 51 and 52 mm SL, were taken in 80 
ft. of water due west of Egmont Key on De- 
cember 17, 1964. They were obtained in a 
dredge sample of the R/V Hernan Cortez. 


Saurida normant Longley. One specimen, 
273 mm SL, was taken in 20 fathoms at 
27°52N, 83°37 W on April 20 19Gseae 
was captured with a 40-foot fish trawl dur- 
ing operations of the R/V Hernan Cortez. 


Trachinocephalus myops (Forster). This 
species is common in the offshore areas of 
Pinellas County, but not nearly as abundant 
as associated species of Synodus. Our record 
is based on a specimen, 162 mm SL, taken 
by the R/V Hernan Cortez with a trynet on 
December 17, 1964, in 80 ft. of water due 
west of Egmont Key. 

Ophichthus ocellatus (LeSuer.) One speci- 
men, 359 mm TL, was taken by Tom Stokel, 
a commercial bait shrimper, on January 23, 
1964 on the south bank of Bunce’s Pass 
channel in the vicinity of the Sunshine Sky- 
way. It was captured in a frame trawl at 
about 2:00 A.M. 

Bregmaceros atlanticus Goode and Bean. 
One specimen, 42 mm SL, was collected in a 
trawl haul on December 21, 1964, at 27° 
23’N, 83°20'W in 120 ft: of waters feme= 
perature was 20.3°C (bottom). 

Holocentrus bullisi Woods. One individ- 
ual, 123 mm SL, was taken on hook and line 
in 24 fathoms at 27°28’N on August 15, 
1963 by a commercial grouper fisherman. 


Rypticus arenatus Cuvier. Two specimens, 
61 and 82 mm SL, were taken in 26 fathoms 
at 27°30’N, 83°48’W on May 24, 1965. 
They were captured in a 40-foot fish trawl 
during operations of the R/V Hernan 
Cortez. 

Serranus phoeby Poey. One individual was 
collected in 32 fathoms at 27°31’N, 84° 
O1’W on May 24, 1965. It was taken with 
a 40-foot fish trawl during operations of 
the R/V Hernan. Cortez. 

Pseudopriacanthus altus (Gill). One speci- 
men, 67 mm SL, was taken in a wire fish 
trap at 27°56’N, 83°81’W on March 30, 
1965 during operations of the R/V Hernan 
Cortez. Depth was 18 fathoms. 

Apogon psendomaculatus Longley. One 
individual, 52 mm SL, was taken at station 
9 on June 5, 1962. 


No. 4 


Decapterus punctatus (Agassiz). Seven 
specimens (128 to 138 mm SL) were taken 
in a purse seine about 8 miles offshore of 
Clearwater Beach on June 17, 1964. Depth 
was 42 feet and surface salinity and tem- 
perature were 35.6 %« and 29.8°C. 


Mullus auratus Jordan and Gilbert. Three 
individuals, 90 to 96 mm SL, were taken at 
28°0S/N, 83°25’W in a commercial shrimp 
trawl on June 20, 1964. The haul was made 
at night at a depth of 80 feet. Surface sa- 
linity and temperature were 35.6 %o and 
50°C: 

Pagrus sedectm Ginsburg. One specimen, 
317 mm SL, was taken by hook and line on 
May 23, 1963 about 65 miles offshore of 
Egmont Key. It was caught on a rocky bot- 
tom at about 25 fathoms. 


Bellator militaris (Goode and Bean). One 
individual, 42 mm SL, was taken at station 3 
in the June collection. 


Prionotus ophryas Jordan and Swain. One 
specimen, 104 mm SL, was taken in 18 fath- 
oms at 27°406’N, 83°35’W on May 23, 1965, 
with a 40-foot fish trawl during operations 
of the R/V Hernan Cortez. 


Prionotus pectoralis Nichols and Breder. 
One specimen, 81 mm SL, was taken in the 
March collection at station 4. 


Opisthognathus lonchurus Jordan and Gil- 
bert. One specimen, 105 mm SL, was found 
in the spewings of a large red grouper taken 
in 25 fathoms at 27°42’N on May 23, 1963. 
The jawfish is in excellent condition and 
had evidently been ingested only a short 
while before the capture of the red grouper. 


Kathetostoma albigutta (Bean). Three 
specimens, 70, 100, and 239 mm SL, were 
taken in the same trawl haul as the previous- 
ly Isted Rypticus arenatus and the same 
data apply to this record. 


Dactyloscopus tridigitatus Gill. One speci- 
men was taken in a frame trawl by Tom 
Stokel on March 16 ,1965 in 4 ft. of water 
on the bay side of Egmont Key. A stand of 
Thalassia testudinum covered the sandy bot- 
tom. 


Paraclinus fasiciatus (Steindachner ). One 
specimen, 39 mm SL, was collected in a dip 
met at the surface near the St. Petersburg 
Municipal Pier on May 31, 1963 by Tom 
Stokel. The Municipal Pier is located on 
Tampa Bay at about 27°46’N. Depth varies 
from 20 to 25 ft. 


Offshore Fishes from Florida 


149 


Blennius nicholsi Tavolga. One individ- 
ual, 27 mm SL, was taken by W. K. Porter 
from near the dock on his property, 8430 
Gulf Boulevard, St. Petersburg Beach, in 
August of 1963. 


Ophidion welshi (Nichols and Breder ). 
Two individuals, 252 and 265 mm TL, were 
taken in December at station 7. Four other 
specimens of O. welshi were subsequently 
taken at stations 2 and 3. 


Ophidion beani Jordan and Gilbert. One 
specimen was taken at station 7 in the March 
collection. 

Otophidinm grayi Fowler. One specimen, 
200 mm TL, was taken at station 7 in the 
March collection. 

Lepophidium jeannae Fowler. One indi- 
vidual, 287 mm TL, was taken in the Febru- 
ary collection at station 9. 


Psenes regulus Poey. Two specimens, 121 
and 116 mm SL, were taken in 92 ft. of 
water due west of Egmont Key on December 
16, 1964. They were collected with a large 
mid-water trawl operated from the R/V 
Hernan Cortez. 

Bothus sp. (unnamed). Two specimens 
were taken during our study. One, 92 mm 
SL, was taken in January at station 6; and 
one, 80 mm SL, was taken at station 7 in 
April. 

Bothus ocellatus (Agassiz). Two speci- 
mens were taken during our study. One, 51 
mm SL, was taken at station 6 in December; 
and one, 97 mm SL, was taken at station 9 
in June. 

Cyclopsetta fimbriata (Goode and Bean). 
One individual, 216 mm SL, was taken at 
station 8 in February. 

Etropus rimosus Goode and Bean. This 
species is discussed in the text of this paper. 

Syacum papilosum (Linnaeus). This spe- 
cies is also discussed in the text of this paper. 

Symphurus diomedianus (Goode and 
Bean). Three individuals, 153 to 154 mm 
SL, were taken in the June collection at 
station 9. 

Symphurus minor Ginsburg. One speci- 
men, 45 mm SL, was taken in 80 ft. of water 
due west of Egmont Key on December 17, 
1964. It was collected in a dredge sample 
from the R/V Hernan Cortez. 


Symphurus urosplus Ginsburg. One speci- 
men, 160 mm TL, was taken in the same 
haul as the previously listed Muallus auratus 
and the same data apply to this fish. 


150 


Alutera heudelotu Hollard. Three indi- 
viduals, 174, 187 and 195 mm SL, were taken 
in 22 fathoms at 27°37’N, 83°43’W on May 
23, 1965 with a 40-foot fish trawl during 
operations of R/V Hernan Cortez. 

Lactophrys triqueter (Linnaeus). One 
specimen, 36 mm TL, was taken in a frame 
trawl on February 9, 1965 by Mr. Tom Stokel 
in 4 ft. of water on the Bay side of Egmont 
Key. 

Halieutichthys aculeatus (Mitchill). Seven 
specimens were taken at station 9 in the 
June collection. One individual measured 
80 mm TL and 49 mm disk width. All fish 
were about the same size. 


SUMMARY 


1. From November, 1962 to June, 1963 
fishes taken during a study of adult pink 
shrimp offshore of Pinellas County, Florida, 
were retained for monthly biological analy- 
sis. These fishes were taken by a 16-foot 
trynet at monthly intervals from nine sta- 
tions. Gear was selective for the smaller, slow- 
moving bottom fishes. Few very young or 
relatively large fish were taken. 


2. The stations have been grouped in 
general depth ranges. These are: stations 2 
and 3, shallow, 15 to 18 feet; stations 1, 4, 
6, and 7, mid-depth, 25 to 45 feet; and sta- 
tions 8 and 9, deep, 75 to 105 feet. Station 
5 was discontinued before the detailed analy- 
sis of fishes was begun. Stations 2, 3, 4, and 
6 produced 90.1 percent of the total catch. 
Data from the other stations are supple- 
mentary to these basic collections. 

3. A total of 2,317 fishes representing 
34 families and 72 species was collected at 
these stations. Twelve species composed 
89.4 percent of the total catch and are dis- 
cussed in detail. The occurrence of the other 
species is presented in tabular form. 

4. A difference of only 6 “%c between the 
highest and lowest salinity reading was re- 
corded during our study; thus, salinity 1s 
not considered a significant factor. Temper- 
atures ranged from 12.4°C in December to 
28.4°C in June. 

5. The largest individuals of each species 
were generally found at the deeper stations. 


6. The depth relationships of the 12 spe- 
cies most numerous in the catch are analyzed. 
Definite depth preferences were found in 
most species within the depth range of the 
study, 3 to 18 fathoms. 


Tulane Studies in Zoology 


Vol. 12 


7. Fifteen of the 72 species taken had not 
previously been reported from the Tampa 
Bay area. These 15 species, along with 27 
other species taken in incidental collections, 
are listed with data as new additions to the 
ichthyofauna of the Tampa Bay area. A total 
of 312 species of fish are now reported from 
this area. 


ACKNOWLEDGMENTS 


It is our pleasure to acknowledge the fol- 
lowing individuals for their contributions 
toward the completion of this paper. Mr. 
Vernon Senterfitt aided in the field work 
and in compilation of data and Mr. Phillip 
Heemstra assisted with the sorting and iden- 
tification of specimens. Doctors C. Richard 
Robins, Donald P. deSylva, and Victor G. 
Springer graciously reviewed the manuscript 
and offered valuable criticisms and sugges- 
tions toward improvement. Mr. Robert M. 
Ingle, Director of Research of the Salt Water 
Fisheries Division of the Florida Board of 
Conservation critically reviewed the manu- 
script and offered encouragement throughout 
the study. 


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October 11, 1965 


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