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of the
FLORIDA STATE MUSEUM
Biological Sciences
VOLUME 29 1984 NUMBER
SCUTELLATION VARIATION IN
OPHEODRYS AESTIVUS
ARNOLD B. GROBMAN
UNIVERSITY OF FLORIDA
GAINESVILLE
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ERRATA SHEET
BULLETIN of the Florida State Museum
Scutellation Variation in
Opheodrys aestivus
Author: AroldB. Grobman
Volume 29 Number 3
This should be listed as
Volume 29 Number 4
on the cover and in the running
heads.
INSIDE FRONT COVER READS:
Consultants for this issue:
James E. Bohlke
Victor G. Springer
Should be:
James R. Dixon
Kenneth L. Williams
SCUTELLATION VARIATION IN
OPHEODRYS AESTIVUS
ARNOLD B. GROBMAN'
ABSTRACT Variation in the scutellation of Opheodrys aestivus is analyzed. North-south
dines are demonstrated in the number of ventrals and caudals and the pattern of scale
row reduction. Sexual dimorphism is described for the number of ventrals, the number
of caudals, the locus of dorsal scale row reduction, and the locus of the umbilical scar.
Taxonomic considerations result in the recognition of four races; two are newly described
(carinatus and conanti); one is resurrected (majalis Baird and Girard 1853); and the
nominate race is redefined. Two additional variant populations are noted but are not
given taxonomic recognition.
RESUMEN Se analiz6 la variaci6n en la escamaci6n de Opheodrys aestivus. Se demonstr6
clinas de norte a sur en el numer6 de escamas ventrales y caudales, asi como en el modelo
de reducci6n en filas de escamas. Se describi6 el dimorfismo sexual de acuerdo al numer6
de escamas ventrales, caudales, el locus de reducci6n de filas de escamas dorsales, y el
locus de la marca umbilical. Consideraciones taxon6micas permiten reconocer 4 razas;
dos son descritas por primera vez (carinatus y conanti) una ha sido restaurada (majalis
Baird y Girard 1853); y la raza nominal es redefinida. Se menciona dos poblaciones
variantes adicionales pero no se les da reconocimiento taxon6mico.
TABLE OF CONTENTS
INTRODUCTION ...................... .............. .. ..................... 153
ACKNOWLEDGEMENTS ......... ................ .............................. 154
M ATERIALS STUDIED ...................................... ................ 154
M ETHODS ................ ............. ........................................ 155
RESULTS ........... ................... ................ .......... 155
Clinal Variation. ................................................. 155
Sexual Dimorphism ............................................... 157
TAXONOMIC CONSIDERATIONS ................... ............................ 160
Opheodrys aestivus aestivus (Linneaus) ................................ 160
Opheodrys aestivus majalis (Baird and Girard) ......................... .162
Opheodrys aestivus carinatus, new subspecies .......................... 164
Opheodrys aestivus conanti, new subspecies .......................... 166
TAXONOMIC SUMMARY ................... .......... ..................... ..167
LITERATURE CITED ....... .. ................................. 170
INTRODUCTION
Since Cope's (1900) extensive compendium on the reptiles of North
America, virtually all the wide-ranging species of snakes in the United
States have been the subjects of variational studies. Over 40 years ago,
I (Grobman 1941) prepared a paper on the variation in the scutellation
of the Smooth Green Snake, Opheodrys vernalis. In the present ac-
'Professor of Biology and Chancellor, University of Missouri, St. Louis, Missouri 63121, and Adjunct Curator, Depart-
ment of Natural Sciences, Florida State Museum, University of Florida, Gainesville, Florida 32611.
GROBMAN, A. B. 1984. Scutellation Variation in Opheodrys aestivus. Bull. Florida State
Mus., Biol. Sci. 29(4):153-170.
BULLETIN FLORIDA STATE MUSEUM
count, I offer a similar analysis of the Rough Green Snake, Opheodrys
aestivus, one of the few remaining species of United States snakes for
which no such report exists.
ACKNOWLEDGEMENTS
I am pleased to acknowledge the generous cooperation of many individuals and their
institutions for the loan of specimens and for responses to my queries, thereby greatly
facilitating my investigations. Acronyms are provided for the collections containing
specimens used in this study. The addresses of persons given are those that were cur-
rent at the time of our correspondence. In particular, I wish to thank: Robert W. Bowker
and Douglas Rossman, Museum of Zoology, Louisiana State University (LSU); W. Leslie
Burger, Japan Snake Institute; Steven P. Christman, U.S. National Fish and Wildlife
Laboratory, Gainesville, Florida (formerly of the Department of Zoology, University of
Florida); F. Wayne King and Peter A. Meylan, Florida State Museum, University of Florida
(FSM); Joseph T. Collins, Museum of Natural History, University of Kansas (KU); Ronald
I. Crombie, National Museum of Natural History, Smithsonian Institution (USNM); James
R. Dixon, Texas Cooperative Wildlife Collection, Texas A & M University (TCWC); Carol
Fieber, Dennis M. Harris, Alan Jaslow, A. G. Kluge, and Ronald Nussbaum, Museum of
Zoology, University of Michigan (UMMZ); Dean Metter and Walter A. Schroeder, University
of Missouri-Columbia; George W. Foley, American Museum of Natural History (AMNH);
Michelle Hudson, Department of Archives and History, Jackson, Mississippi; C. J. McCoy,
Carnegie Museum (CM); Benjamin Shreve and Ernest E. Williams, Museum of Comparative
Zoology, Harvard University (MCZ); Dorothy Smith, Museum of Natural History, University
of Illinois (UIMNH); and Phillip W. Smith, Illinois Natural History Survey (INHS). I am
grateful also to the authorities of the Chicago Academy of Sciences (CA) and the Field
Museum of Natural History (FMNH), who graciously permitted examination of specimens
in their laboratories.
Most of the demanding work of recording scale counts was performed by Allan
Markezich who, at the time that phase of the study was pursued, was a graduate stu-
dent at the University of Illinois at Chicago Circle. I am deeply indebted to him for his
careful recording of data and for his many valuable and thoughtful suggestions. Hobart
M. Smith, Department of Biology, University of Colorado, and Roger Conant, Depart-
ment of Zoology, University of New Mexico, were especially helpful in reviewing early
drafts of the manuscript. I acknowledge, also, the helpful suggestions of anonymous
reviewers.
MATERIALS STUDIED
The Opheodrys aestivus material available in major American collections made it possible
to extract scutellation data from 1154 specimens with precise locality (county or better)
data. This report is the result of an analysis of those data.
Two cataloged specimens with specific locality data have been excluded from the
analysis. They are:
CM 1322, Ninveh, Green Co., PA, D. A. Atkinson, 31 May 1922. The nearest records
to Ninveh I know of are 110 miles to the southwest and 130 miles to the east. Apparent-
ly no additional specimens have been collected in the intervening region despite the ac-
tivities of local herpetologists over many years. I have given reasons (Grobman 1950)
for questioning the authenticity of a specimen of O. vernalis (CM 422) Atkinson collected.
It appears prudent to discard locality data accompanying CM specimens Atkinson
collected.
USNM 7196, Cimmaron, NM, S. A. Clark. Mr. R. I. Crombie (in litt., 13 November 1974)
advised that no other specimens (which might assist in identifying the region of collec-
tion) are associated with this snake nor has the collector donated other materials. Fur-
VOL. 29, NO. 3
1984 GROBMAN: OPHEODRYS AESTIVUS SCUTELLATION VARIATION 155
their, the scale counts for this male specimen (ventrals 153, caudals 129) resemble those
of eastern specimens somewhat more than those of western specimens of 0. aestivus.
The same specimen is listed by Cope (1900) as from the Cimmaron River, and one with
an adjacent catalogue number (USNM 7197) is listed as Ft. Bliss, New Mexico, but Crom-
bie suggested the latter may be from Texas. Cope also listed a specimen (USNM 11825)
as donated by E. Palmer and gave the locality as Old Fort Cobb, New Mexico.
As the "New Mexico" of the nineteenth century was a very inclusive term; as collec-
tors along the Cimmaron River in Oklahoma (where 0. aestivus occurs) may have sent
their collections to army forts in New Mexico and elsewhere for shipment to Washington;
and as the nearest point in the present State of New Mexico is more than 150 miles west
of the westernmost specimen of Opheodrys aestivus, I do not consider those cited 19th
century "New Mexico" locality records to represent sites in the present State of New
Mexico.
METHODS
Opheodrys aestivus is a green snake with no dorsal or ventral color pattern, and so
a study of its external morphology must rest almost exclusively on an examination of
meristic characters. I examined a variety of these characters in some detail, and those
I found to be useful are the number of ventrals, the number of caudals, the degree of
keeling of the dorsal scales, the method of dorsal scale row reduction (from 17 rows
anteriorly to 15 rows posteriorly), and the locus (i.e. opposite which ventral) of dorsal
scale row reduction. Head plate arrangements did not vary significantly in the specimens
examined, and body and tail length measurements were not recorded.
RESULTS
Clinal variation (north/south; not east/west), beyond that ascribable
to race, occurs in number of ventrals and caudals and pattern of dor-
sal scale row reduction.
Sexual variation occurs in the number of ventrals, number of caudals,
locus of dorsal scale row reduction, and locus of the umbilical scar.
Geographic variation (not primarily clinal) suggests the recognition
of four races of Opheodrys aestivus. Two additional populations are
identified through scutellation characteristics but are not given tax-
onomic recognition.
CLINAL VARIATION
1. VENTRALS AND CAUDALS
Ventrals and caudals exhibit a geographic gradient, with the southern
specimens of Opheodrys aestivus having a larger number than northern
specimens.
In order to minimize the effect of other trends (discussed below) on
an analysis of possible clinal variation, the samples selected for a
preliminary study were restricted to specimens collected in Illinois, In-
diana, Ohio, Kentucky, West Virginia, and Tennessee (northwestern
quadrant); Alabama, Mississippi, and Louisiana (southwestern
quadrant); New Jersey, Delaware, Maryland, the District of Columbia,
and Virginia (northeastern quadrant); and Georgia, South Carolina, and
BULLETIN FLORIDA STATE MUSEUM
North Carolina (southeastern quadrant).
Comparisons of ventral and caudal counts between northern and
southern samples show higher values for the southern specimens, with
southern snakes having about 2.75 more ventrals and about 7 more
caudals than northern snakes.
In similar comparisons between western and eastern specimens, the
sample value for ventrals for the western specimens is about 1.25 higher
and for caudals about 1.67 lower than for the eastern specimens. The
data (summarized in Table 1) do not support a suggestion that a
demonstrable east-west dine exists in the number of ventrals plus
caudals.
TABLE 1.-Mean number of ventrals and caudals, with number of specimens indicated
in parentheses, in selected samples (see text).
Western Eastern
Northern
Male ventrals 153.5 (113) 151.9 (71)
Female ventrals 156.0 (93) 154.4 (67)
Male caudals 131.9 (97) 131.3 (59)
Female caudals 124.7 (63) 124.5 (45)
Southern
Male ventrals 155.4 (64) 154.8 (63)
Female ventrals 159.3 (57) 157.4 (60)
Male caudals 135.5 (48) 139.0 (42)
Female caudals 130.8 (44) 132.7 (44)
To study the north-south cline in ventrals plus caudals more closely,
and to reduce heterogeneity associated with racial differences (see
below), an analysis was made of specimens collected from all localities
other than those in Missouri, Kansas, Arkansas, Oklahoma, Texas, and
Mexico; and the offshore islands of Virginia.
Table 2 gives the modal latitude of collections by localities and the
mean number of ventrals plus caudals of specimens in those collections.
The latitudes are representative of the collection samples, and the
scutellation data are the weighted means of the total ventral and caudal
counts for males and females combined.
A best-fit regression line indicates 296 ventrals plus caudals to be
typical of snakes living near the 30 parallel and 281 ventrals plus
caudals to be typical at the 40 o parallel. Thus it appears that a decrease
of one degree of latitude is accompanied by an increase of about 1.5
ventrals plus caudals.
2. SCALE ROW REDUCTION
Ophedrys aestivus typically has 17 rows of dorsal scales, and that
number reduces posteriorly to 15 about two-thirds of the distance from
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1984 GROBMAN: OPHEODRYS AESTIVUS SCUTELLATION VARIATION 157
Table 2.-North-south dine in ventrals plus caudals.
Mean No. of
ventrals plus
No. of
Latitude caudals Specimens States Included
300 30' 295.3 34 FL
310 289.9 51 LA
320 30' 294.0 65 AK, GA, MS
330 30' 294.0 33 SC
350 30' 288.5 30 NC
360 284.5 53 TN
370 30' 284.9 62 VA, KY
380 285.4 43 IL
380 30' 281.5 39 WV, IN
390 283.1 35 DC, MD
400 286.6 8 NJ
the head. The patterns of reduction and the percentages of occurrence
of those patterns, based on 1875 observations, are as follows: fusion
of rows 3 + 4 (78.2%), fusion of rows 2 + 3 (14.7%), elimination of
row 3 (5.6%), fusion of rows 4 + 5 (0.8%), elimination of row 4 (0.6%),
and elimination of row 2 (one instance).
Considerable geographic variation occurs in the patterns of reduc-
tion, and though there appears to be some sexual dimorphism (the males
being slightly less variable, a higher proportion having the 3 + 4 pat-
tern), the degree of that dimorphism is slight compared to the observ-
ed geographic variation.
The fusion of rows 2 + 3 occurs more often in northern specimens,
less often in southern specimens, and the converse is true of the fu-
sion of rows 3 + 4. The trend is exhibited in Table 3, which shows the
percentage of specimens in which scale row reduction involves dorsal
row 4 (either through fusion or elimination) from localities in states
bordering the East Coast.
Table 3.-Percentage of specimens in which dorsal row four is involved in scale row
reduction.
Mean
Locality Number Latitude Percent
NJ-MD 70 39 52.9
VA 51 370 66.7
NC-SC 84 350 72.6
GA-N. FL 132 320 85.6
S. FL 241 270 89.6
SEXUAL DIMORPHISM
1. VENTRALS AND CAUDALS
Males appear to have approximately 3 fewer ventrals and 7 more
BULLETIN FLORIDA STATE MUSEUM
caudals than females.
The mean number of ventrals in 569 males is 155.3 0.31 and in
576 females, 158.5 + 0.32. The mean number of caudals in 427 males
is 132.9 + 0.58 and in 411 females, 125.2 0.59.
With the more attenuated tail in males, it might reasonably be assum-
ed that among museum specimens their proportion of broken and
therefore incomplete tails would be slightly higher than in females. The
data do not support that assumption. Among 569 specimens of males
examined, 427 had complete tails, and thus about 25% of the tails were
incomplete; in the samples of females, 29% had incomplete tails. A Chi-
square value of 0.19 supports the interpretation that the observed dif-
ference could well be due to chance sampling errors.
2. SCALE ROW REDUCTION
The place where the dorsal scale rows reduced from 17 to 15 rows
was recorded as the number of the ventral scale opposite the place of
reduction. During a preliminary part of this study I used a ratio,
calculated for each side of a specimen, simply by dividing the number
of the ventral scale at the reduction point by the total number of ven-
trals. As the resulting ratios are similar in the four subspecies iden-
tified below, the place of scale row reduction reflects no obvious dif-
ferences among those races.
To investigate whether clinal or other geographic differences might
be associated with the place of scale row reduction, the data were
segregated into geographic samples, as defined earlier, representing
specimens from northwestern, northeastern, southwestern, and
southeastern quadrants. No differences of consequence were noted
that could be related to geography, but in all four samples the ratio
was lower in females than in males.
In males the mean ratio at the point of reduction is 63.6 + 0.17 and
in females it is 61.7 0.18. The difference is small, 1.9, but contain-
ing its standard error, 0.25, more than seven times, is statistically
significant.
A subsequent means of analysis was through the use of the locus of
Table 4.-Mean locus, by ventral number, of reduction of dorsal scale rows in O. a.
aestivus.
Sex Males Females
Number of Specimens 333 331
Mean number of ventrals
anterior to reduction 97.7 96.8
Mean number of ventrals
posterior to reduction 56.5 60.2
Mean total number of ventrals 154.2 157.0
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1984 GROBMAN: OPHEODRYS AESTIVUS SCUTELLATION VARIATION 159
reduction by actual ventral number instead of by ratios. The data of
Table 4 were obtained by restricting that analysis to O. a. aestivus (see
below for definition of races) to reduce heterogeneity.
These data are consistent with the following: In O. a. aestivus females
have about 3 more ventrals than males. The corresponding elongation
in the females occurs primarily in the posterior third of the body be-
tween the anal plate and the point of dorsal scale row reduction.
Females show a slight increase in body length, as reflected by the
number of ventrals, that may be associated with the retention of matur-
ing ova, but no comparable accommodation in girth is apparent, for
the length of the body with a reduced number of dorsal scale rows ac-
tually is greater in females than males.
Little bilateral variation occurs. The locus of reduction on the left
side of a specimen is about 2.3 ventral scales from the place of reduc-
tion on the right side of that specimen. The observed bilateral varia-
tion is summarized in Table 5.
Table 5.-Bilateral variation in locus of scale row reduction in 941 specimens; difference
indicates the number of ventrals between the locus of reduction on one side of the
specimen and the locus on the other side.
Difference Percentage
0 18.8
1 25.3
2 21.6
3 12.5
4 9.8
5 3.9
6 2.9
7 1.7
8+ 3.5
3. UMBILICAL SCAR
Four specimens, two of which were litter mates, had visible umbilical
scars; the data are given in Table 6. Although the data at hand are scant,
they support the view that geographic and sexual variation in the
number of ventrals occurs primarily anterior to the umbilicus, for the
number of ventrals between the umbilicus and the anal plate appears
to be relatively constant at about 20. Tinkle (1960) made a similar obser-
vation based on a study of 142 specimens of 0. aestivus from Jeffer-
son Parish, Louisiana.
The locus for most of the sexual variation in the number of ventrals
in 0. aestivus appears to be the region between the place of scale row
reduction and the umbilicus. The region of greatest variability in the
number of ventrals in aestivus seems to lie between ventrals 97 and
136. In an idealized male specimen of Opheodrys aestivus with 155 ven-
BULLETIN FLORIDA STATE MUSEUM
trals, scale row reduction is opposite the 98th ventral and the center
of the umbilicus is at the 135th ventral.
TAXONOMIC CONSIDERATIONS
An analysis of the data suggests that Opheodrys aestivus contains
no less than four subspecies. This report recognizes subspecies if 75%
of the available specimens can be correctly assigned to their geographic
provenience by scutellation characters. Geographic discontinuities in
the scutellation characters are the basis for the generalized racial
distributions shown in Figure 1. Each spot on the map indicates a coun-
ty or parish (or specific location in Mexico) from which one or more
specimens have been examined. The dashed lines separating the races
pass through areas of intergradation.
FIGURE 1.-Distribution of the subspecies of Opheodrys aestivus. Each spot indicates a
county, parish, or specific locality in Mexico, from which one or more specimens were
examined during the present study.
OPHEODRYS AESTIVUS AESTIVIS (LINNEAUS)
A subspecies of 0. aestivus ranging from southern New Jersey south-
ward to northern Florida, westward to eastern Texas; replaced to the
VOL. 29, NO. 3
1984 GROBMAN: OPHEODRYS AESTIVUS SCUTELLATION VARIATION 161
west by O. a. majalis, and to the south in Florida by O. a. carinatus;
and usually having the following set of characters: keeling absent on
the third dorsal row (opposite the seventh ventral); ventrals 151 or more
in males, 155 or more in females; and caudals 128 or more in males,
122 or more in females.
NEOTYPE. USNM 92473, male, collected one mile west of Parksville,
McCormick Co., SC, by C. W. Burn, 19 July 1933. Ventrals 159, caudals
140, initial dorsal row keeling (opposite 7th ventral) 4th row, reduc-
tion from 17 to 15 scale rows, fusion of rows 2 and 3 opposite 99th
ventral on the left side, fusion of rows 3 and 4 opposite 95th ventral
on the right side. Because additional geographic races are being
recognized, it appears desirable to designate a neotype for aestivus to
provide a definitive fixation of the name. Schmidt (1953) arbitrarily
restricted the type locality, Carolina, given by Linnaeus for aestivus,
to Charleston. In designating a neotype I depart from Schmidt's sug-
gestion because my small study sample from the Charleston area in-
cludes no male specimen with precise locality data and scutellation
characteristics typical of Opheodrys a. aestivus.
EXEMPLARY MATERIAL. UMMZ 129086, male, Savannah River Plain,
Aiken, SC; USNM 110469, male, 5 miles NE Bluffton, SC; FMNH 52971,
male, Leesville, SC; UIMNH 18628, male, 14.5 miles S Hopeville, GA;
AMNH 99047, male, Tobacco Road and Route 25, Richmond County,
GA; LSU 2760, male, 2-V1 miles S University, Baton Rouge, LA: USNM
13006, male, New Orleans, LA; USNM 56386, Mobile, AL; UIMNH
21623, male, Pell City, AL; UMMZ 93985, male, Handsboro, MS; USNM
145616, male, Wilmington, NC; USNM 66594, female, Barachias, AL;
MCZ 13146, female, Jacksonville, FL; UMMZ 72813, female, Lake Sam-
pala, FL; USNM 10710, female, Nashville, GA; FMNH 155008, female,
10 miles SE Columbus, GA; CA 4112, female, Sherwood Plantation,
Grady County, GA; AMNH 99049, female, August, GA; LSU 2761,
female, Baton Rouge, LA; UIMNH 29136, female, Gulf Coast Research
Laboratory, Jackson County, MS; USNM 91766, 4 miles N Monroe, NC;
FSM 9056, 1 mile S Beulah Pond, Aiken County, SC; USNM 1449,
female, Anderson, SC; and CM 9560, Bowman, SC.
SCUTELLATION CHARACTERISTICS. The mean number of ventrals in 357
males is 154.2 + 0.20; in 317 females, 157.0 0.22. The mean number
of caudals in 270 males is 135.0 0.45, in 217 females, 128.5 + 0.46.
Keeling is usually absent on the third dorsal scale row opposite the
seventh ventral.
Two distinguishable populations of O. a. aestivus, for which tax-
onomic recognition does not now seem appropriate, are indicated
below.
BULLETIN FLORIDA STATE MUSEUM
An identifiable population of aestivus occupies a narrow strip of
coastal plain from the easternmost parishes of Louisiana eastward
through the coastal counties of Mississippi and Alabama through the
panhandle of Florida and northward through the coastal counties of
Georgia and South Carolina. Specimens in the region so defined have
about nine more caudals than do specimens of aestivus lying outside
that coastal plain strip. For example, the mean value of the caudals
of the coastal plain male specimens is 143.6 1.34 and of the remain-
ing male specimens of aestivus, 134.1 + 0.44. The difference between
the means contains its standard error about 6.6 times and so appears
to be statistically significant.
Slightly more than half the specimens from Tennessee and Kentucky
demonstrate the 3 + 4 fusion pattern of reduction in dorsal scale rows
in contrast to its appearance in about three-fourths of the individuals
from adjacent states. There appears to be a biologically (Chi-square
value is 18.6), but not nomenclaturally (does not reach 75% separa-
tion) identifiable population in Kentucky and Tennessee that differs
from specimens in adjacent states in the pattern of scale row reduc-
tion. In reducing from 17 to 15 dorsal rows, rows 3 and 4 fuse in 56%
of the individuals in the Kentucky and Tennessee population, whereas
in other specimens of the same race, rows 3 and 4 fuse in 74% of the
specimens. In Kentucky and Tennessee specimens, reduction by fusion
of rows 2 and 3 occurs almost twice as frequently as in adjacent
populations.
OPHEODRYS AESTIVUS MAJALIS (BAIRD AND GIRARD)
A subspecies of 0. aestivus ranging from northeastern Mexico through
central and eastern Texas (except that part adjacent to Louisiana),
eastern Oklahoma, southern Kansas, central Missouri, and the vicini-
ty of St. Louis in Illinois; and usually having the following set of
characters: Keeling absent on 3rd dorsal row (opposite 7th ventral);
ventrals 155 or more in males, 155 or more in females; and caudals 127
or fewer in males, 121 or fewer in females.
LECTOHOLOTYPE. USNM 1436-A, female, collected in the vicinity of
Indianola, Calhoun County, TX, by I. D. Graham. (This specimen is iden-
tified as a "co-type" = syntype of Leptophis majalis, Baird and Girard
1853 in the Museum's records.) Ventrals 160; caudals 111; initial dor-
sal row keeling (opposite 7th ventral), 4th row; reduction from 17 to
15 dorsal scale rows, fusion of rows 3 and 4 opposite 91st ventral on
the left side, opposite 83rd ventral on the right side.
EXEMPLARY MATERIAL. UIMNH 62210, male, Lawrence, KS; KU
35888, male, Independence, KS; USNM 15648, male, Oswego, KS; KU
38308, male, Las Margaritas, Mexico; UMMZ 69251, male, LaVegonia,
VOL. 29, NO. 3
1984 GROBMAN: OPHEODRYS AESTIVUS SCUTELLATION VARIATION 163
Mexico; KU 45369, male, Osage Hills State Park, OK; UIMNH 17375,
male, Dawson, OK; TCWC 15237, male, near Medina, TX; CM 19906,
male, 4 miles NW Helotes, TX; UMMZ 114371, male, Brownsville, TX;
UMMZ 116208, male, Houston, TX; USNM 32759, male, Corpus Christi,
TX; KU 45334, female, Elk City, KS; UIMNH 15716, female, Ottawa,
KS; UMMZ 84020, female, Stillwater, OK; KW 61083, female, College
Station, TX; MCZ 2500, female, Dallas, TX; AMNH 86934, female,
Palmetto State Park, TX; FSM 4341, female, near San Marcos, TX; and
CA 11215, female, 20 miles SW Abilene, TX.
SCUTELLATION CHARACTERISTICS. The mean number of ventrals in 122
males is 157.0 + 0.30; in 167 females, 159.5 + 0.29. The mean number
of caudals in 99 males is 125.7 + 0.60; in 117 females, 116.4 + 0.51.
Keeling is usually absent on the 3rd dorsal scale row opposite the 7th
ventral.
NOMENCLATURAL NOTES. Baird and Girard (1853) described Leptophis
majalis as differing from Leptophis aestivus in having a proportionately
shorter tail. The tabulation of caudal counts for ten specimens given
by those authors supports that observation. Baird and Girard also
reported that a variety of body, head, and scale proportions in ma-
jalis differed from those in aestivus.
Cope (1900), in reviewing Baird and Girard's account about a half-
century later, confirmed that individuals from "New Mexico" did have
shorter tails than those from the Atlantic region, but he considered "the
graduation in length" to be "complete." He did not comment on the
other differences Baird and Girard mentioned and did not include ma-
jalis among the forms he recognized.
My observation of a reduced number of caudals agrees with the obser-
vations of Baird and Girard and of Cope on tail length. The number
of caudals of specimens from contiguous areas in Kansas, Oklahoma,
Texas, Arkansas, Missouri, and Mexico is substantially less than that
of individuals from the more eastern parts of the range of the species.
I have not found the cline suggested by Cope, nor have I found cephalic
scales differences, and so cannot evaluate those observations of Baird
and Girard.
The name majalis was applied to western specimens of aestivus
recently by Smith (1956), Webb (1970), and Lardie (1975) and, in do-
ing so, they followed the usage of Burger in an unpublished manuscript
intended to be part of a dissertation for an advanced degree at the
University of Oklahoma. A brief abstract (Burger 1947) is the first
published usage known to me of the combination Opheodrys aestivus
majalis.
BULLETIN FLORIDA STATE MUSEUM
OPHEODRYS AESTIVUS CARINATUS, NEW SUBSPECIES
A subspecies of 0. aestivus occurring in the southern half of the
Florida peninsula that differs from the other races of aestivus in being
more strongly keeled. The scale in the 3rd dorsal row opposite the 7th
ventral is usually keeled (the racial name refers to this characteristic).
The number of ventrals is usually 155 or more. The number of caudals
in males is usually 128 or more; in females 122 or more.
HOLOTYPE. AMNH 65637, male, Archbold Biological Station,
Highlands Co., FL, collected by C. M. Bogert in 1944. Ventrals 165,
caudals 138, initial dorsal row keeling (opposite 7th ventral) 2nd row,
reduction from 17 to 15 dorsal scale rows, dropping of row 3 opposite
100th ventral on the left side, 102nd on the right.
PARATYPES (all from Florida). AMNH 6911, male, Eau Gallie; USNM
13676, male, Georgiana; UMMZ 108227, male, 11 miles NNW Miami;
MCZ 28205, male, Homestead; CM 8218, male, 5 miles NE La Bell;
UMMZ 106227, male, 1 mile W Monroe Station; FSM 9092, male, 3 miles
S Aripeka on US 19; UMMZ 108226, female, 10 miles NW Miami; UIMNH
43020, female, 3 miles N junction Routes 27 and 561; CA 12179, female,
Leesburg; FSM 2396, female, Palmetto; FMNH 95214, female, Orlan-
do; MCZ 46893, female, Sebastian; and USNM 86832, female, Sarasota.
SCUTELLATION CHARACTERISTICS. The mean numbers of ventrals in 73
males is 158.7 + 0.51; in 96 females, 163.2 + 0.43. The mean number
of caudals in 45 males is 139.6 + 1.06; in 66 females, 130.8 + 0.69.
Keeling is usually present on the 3rd dorsal scale row opposite the 7th
ventral and, often, on the 2nd row.
DISTRIBUTIONAL NOTES. Cope (1900) implied the existence of an iden-
tifiable southern population with this phraseology: "Floridan specimens
differ from others in having the keels of the scales stronger and hav-
ing the 2nd row strongly keeled like the 3rd, while it is smooth in other
specimens; but no other character coincides with this one."
About 36% of the south Florida specimens have the 2nd row keeled
opposite the 7th ventral scute, but this occurs in fewer than 1% of
specimens from more northern localities. Virtually all of the south
Florida specimens (90%) have keeling present in the 3rd row, opposite
the 7th ventral scute, whereas such keeling is present in but 26% of
the snakes to the north.
Florida specimens of O. a. aestivus are assigned to Orange, Seminole,
Volusia, Flagler, Alachua, and Gilchrist counties and more northern
localities and specimens of O. a. carinatus are allocated to Marion,
Lake, Brevard, and Hernando counties, and southward throughout the
peninsula. The keeling is stronger in specimens of carinatus, and the
difference is greater at the anterior end of the animal than at the
posterior end.
VOL. 29, NO. 3
1984 GROBMAN: OPHEODRYS AESTIVUS SCUTELLATION VARIATION 165
Christman (1980), in reporting on scutellation variation in 176
specimens of Florida green snakes, clearly had identified the difference
in degree of keeling between snakes from southern Florida and those
from central and northern Florida.
Table 6.-Location of umbilical scar in newly born specimens.
Ventral Total
Locality Sex at Scar Ventrals
Brown Co., Indiana F 127 147
Brown Co., Indiana F 128 150
Prince Georges Co., Maryland M 135 155
Escambia Co., Florida M 138 157
Table 7 records the frequency of the dorsal scale row at which keel-
ing first occurs, opposite the seventh ventral scale, in specimens of
aestivus and carinatus. Specimens from the Florida Keys do not ap-
pear to exhibit keeling quite as marked as that in other south Florida
material, but their dorsal scales are more strongly keeled than in O.
a. aestivus. (The data from the Keys specimens are included with
carinatus in Table 7.)
In the available sample of aestivus, 26% have the 2nd or 3rd as the
1st keeled row and 74% have the 4th or 5th as the 1st keeled row. In
the sample of carinatus, the corresponding figures are 90% and 10%.
Thus, in the material at hand, about 78% of the specimens would be
correctly allocated to geographic provenience through use of the follow-
ing couplet:
Third dorsal row keeled ................... ..... carinatus
Third dorsal row not keeled.................... aestivus
Table 7.-First keeled row of dorsal scales opposite seventh ventral.
First Number of Number of
Keeled Row O. a. aestivus 0. a. carinatus
2 9 59
3 229 91
4 652 16
5 23 0
The difference in keeling between specimens of aestivus and carinatus
is highly significant (Chi-square value is 26) and three-quarters of the
available specimens can be accurately assigned to their geographic
ranges through this specific identification character. On the basis of
a much larger sample than he had available, I am able to confirm Cope's
observation on keeling, and by following taxonomic procedures dif-
ferent from those that were current in his day, I find it appropriate
to accord nomenclatural recognition to the south Florida race.
BULLETIN FLORIDA STATE MUSEUM
NOTE ON COLORATION. Carr (1940) and Cushman (1980) indicate that
living specimens of Opheodrys from central and southern Florida have
yellow venters, while specimens from the rest of the range (presumably
north Florida) have white venters. Duellman and Schwartz (1958), in
a study of southern Florida specimens, also note a color change in the
venters. The indications are that the venters of living specimens of
carinatus are yellow (except in the Florida Keys), while those of the
other aestivus races are white.
OPHEODRYS AESTIVUS CONANTI, NEW SUBSPECIES
A subspecies of 0. aestivus, known from the offshore islands
(Assateague, Parramore, Revel, and Smith) of Virginia, that differs from
the other races of 0. aestivus in having a lesser number of ventrals
and caudals. Usually there are 154 or fewer ventrals and the number
of caudals is 127 or fewer in males and 121 or fewer in females.
HOLOTYPE. CM 27847, male, Paramore Island, Accomack Co., VA,
collected by Roger Conant and others 28 April 1947. Ventrals 145,
caudals 114, initial dorsal row keeling (opposite 7th ventral) 4th row
reduction from 17 to 15 dorsal scale rows by fusion of rows 2 and 3
opposite 97th ventral on left side, 96th ventral on right side.
PARATYPES (all from Virginia). AMNH 71022, male, Parramore
Island; CM 27843-46, males, Parramore Island; USNM 165834, male,
Assateague Island; CM 1878, male, Revel Island; AMNH 71023, female,
Parramore Island; CM 27835-38, females, Parramore Island; and USNM
23950, female, Smith Island.
SCUTELLATION CHARACTERISTICS. The mean number of ventrals in 11
males is 148.1 + 1.00; in 11 females 148.8 0.73. The mean number
of caudals in 9 males is 120.9 + 1.23 in 11 females 118.4 + 1.21. Keel-
ing is usually absent on 3rd dorsal scale row opposite the 7th ventral.
DISTRIBUTIONAL NOTES. The available specimens from the offshore
islands of Virginia differ substantially from individuals of the popula-
tions of the adjacent coastal plain of that State. Specimens from
Assateague, Parramore, Revel, and Smith islands average about 15 ven-
trals and caudals less than specimens from mainland coastal Virginia,
with a reduced number of caudals contributing about twice as much
to the difference as do the ventrals. Data for conanti and geographically
adjacent mainland samples of aestivus are shown in Table 8.
The Virginia offshore island specimens can be compared with Virginia
coastal plain specimens and correctly assigned geographically through
either of the following couplets:
A. Ventrals 148 or fewer in males; 151 in females.... conanti
Ventrals 149 or more in males; 152 in females..... aestivus
VOL. 29, NO. 3
1984 GROBMAN: OPHEODRYS AESTIVUS SCUTELLATION VARIATION 167
B. Caudals 123 or fewer ....................... conanti
Caudals 124 or more. ................... .. .. .aestivus
Table 8.-Mean number of ventrals and caudals in specimens of O. a. conanti and
specimens of O. a. aestivus from adjacent coastal Virginia.
Adjacent
Offshore Coastal
Islands Mainland
(conanti) (aestivus)
Number Mean Number Mean
Males, caudals 9 120.9 20 134.3
Males, ventrals 11 148.1 22 153.5
Females, caudals 11 118.4 13 128.1
Females, ventrals 11 148.8 19 156.1
The second couplet correctly allocates 94% of the available
specimens, and the first couplet correctly allocates 85% of the males
and 93% of the females. It therefore appears fitting to recognize the
Virginia islands specimens nomenclaturally.
Although the number of specimens presently available for study from
the offshore islands of North Carolina (Hatteras, Ocracoke, Shackleford
Banks) is quite small, a similar, but quite reduced trend appears to be
present. Specimens from those islands appear to average about four
ventrals plus caudals between specimens from the Keys and those from
Dade County. Based on the material presently available, it would be
ventrals plus caudals between specimens from the Keys and those from
Dade County. Based on the material presently available, it would be
little more than conjecture to postulate a dine in which in-
sular/mainland differences are greater in the northern and less in the
southern parts of the range of 0. aestivus, but the question will be
worth further investigation when more material becomes available for
study.
NOMENCLATURAL NOTE. It seems appropriate to associate with this
race the name of Roger Conant, who has contributed substantially to
our knowledge of the herpetology of the area inhabited by this form.
TAXONOMIC SUMMARY
The four races of Opheodrys aestivus thus delineated can be assign-
ed to proper geographic provenience with better than 82% accuracy
by the following key:
1. Caudals 127 or fewer in males; 121 or fewer in females. .2
Caudals 128 or more in males; 122 or more in females.... 3
BULLETIN FLORIDA STATE MUSEUM
2. Ventrals 154 or fewer. ....................... conanti
Ventrals 155 or more. .......................... majalis
3. Keel on 3rd dorsal row ....................... carinatus
No keel no 3rd dorsal row .................. ... aestivus
Table 9.-Mean number of ventrals in the subspecies of Opheodrys aestivus
Mean Number
Race Number of Ventrals Range
Males
majalis 122 157.0 + 0.30 148-165
aestivus 357 154.2 0.20 144-168
carinatus 73 158.7 0.51 151-168
conanti 11 148.1 1.00 144-153
Females
majalis 167 159.5 0.29 149-170
aestivus 317 157.0 0.22 147-169
carinatus 96 163.2 0.43 153-171
conanti 11 148.8 0.73 145-154
A brief synopsis of those races follows.
O. a. carinatus n. ssp.: heavy keeling and a high number of ventrals
and caudals; limited to the southern half of Florida.
0. a. majalis (Baird and Girard): moderate keeling, high number of
ventrals and low number of caudals; occurring primarily in eastern Kan-
sas, Oklahoma, Texas, northeastern Mexico, and parts of Arkansas,
Missouri, and Illinois.
O. a. aestivus (Linneaus): moderate keeling, moderate number of ven-
trals and high number of caudals, found from New Jersey to Illinois,
south to Louisiana and Florida.
O. a. conanti n. spp.: moderate keeling and a low number of ven-
trals and caudals; occupying the off-shore islands of Virginia.
Table 10.-Mean numbers of caudals in the subspecies of Opheodrys aestivus
Mean Number
Race Number of Caudals Range
Males
majalis 99 125.7 0.60 110-142
aestivus 270 135.0 + 0.45 119-155
carinatus 45 139.6 1.06 125-159
conanti 9 120.9 1.23 114-126
Females
majalis 117 116.4 0.51 105-132
aestivus 217 128.5 + 0.46 111-149
carinatus 66 130.8 0.69 120-143
conanti 11 118.4 1.21 110-124
VOL. 29, NO. 3
MALES
conanti
aestivus
majalis
carinatus
FEMALES
conanti
aestivus
majalis
carinatus
FIGURE 2.-Mean number of ventrals and ventrals plus caudals in both sexes of the subspecies of Opheodrys aestivus.
--/- ---/,-----
I I I I I
S140 150 160 260 270 280 290 300
NUMBER OF VENTRALS PLUS CAUDALS
BULLETIN FLORIDA STATE MUSEUM
Figure 2 diagrams the mean number of ventrals and ventrals plus
caudals of these four races.
Summaries of the ventral and caudal counts of both sexes of the four
recognized races are given in Tables 9 and 10 respectively. The tabular
data include the number of specimens in each sample, the mean and
its standard error, and the highest and lowest variate observed for each
character.
LITERATURE CITED
Baird, S. F., and C. Girard. 1853. Catalogue of North American reptiles in the museum
of the Smithsonian Institution. Smithsonian Institution, Washington. xvi + 172 p.
Burger, W. L. 1947. A taxonomic and statistical study of the keeled green snake,
Opheodrys aestivus. Program of the Chicago Meeting with Abstracts of Papers. Bull.
Ecol. Soc. Amer. 28 (5):54.
Carr, A. F. 1940. A contribution to the herpetology of Florida. Univ. Florida Press, Biol.
Sci. Ser. 3 (1):1-118.
Christman, S. P. 1980. Patterns of geographic variation in Florida snakes. Bull. Florida
State Mus., Biol. Sci. 25 (3): 157-256.
Cope, E. D. 1900. The crocodilians, lizards, and snakes of North America. Rep. U.S. Natl.
Mus., Smithsonian Institution, Washington. xviii + 1294 p.
Duellman, W. E., and A. Schwartz. 1958. Amphibians and reptiles of southern Florida.
Bull. Florida State Mus., Biol. Sci. 3(5):181-324.
Grobman, A. B. 1941. A contribution to the knowledge of variation in Opheodrys ver-
ralis (Harlan), with the description of a new subspecies. Mis. Publ. Mus. Zool. Univ.
Michigan 50:1-38
1950. The problem of the natural range of a species. Copeia 3:231-2.
Lardie, R. L. 1975. Terrapene carolina triunguis. Herp. Rev. 6(2):44.
Schmidt, K. P. 1953. A check list of North American amphibians and reptiles. American
Society of Ichthyologists and Herpetologists. Sixth Edition. vii + 280 p.
Smith, H. M. 1956. Handbook of amphibians and reptiles of Kansas. Univ. Kansas Mus.
Nat. Hist., Misc. Publ. 9:1-357.
Tinkle, D. W. 1960. A population of Opheodrys aestivus (Reptilia: Squamata). Copeia
1:29-34.
Webb, R. G. 1970. The reptiles of Oklahoma. Univ. Oklahoma Press, Norman. xi + 370 p.
VOL. 29, NO. 3
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