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* * * * *
UNIVERSITY OF KANSAS PUBLICATIONS
MUSEUM OF NATURAL HISTORY
Volume 15, No. 6, pp. 251-295, 9 figs.
October 4, 1963
A Revision of Snakes of the Genus Conophis
(Family Colubridae, from Middle America)
BY
JOHN WELLMAN
UNIVERSITY OF KANSAS
LAWRENCE
1963
UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY
Editors: E. Raymond Hall, Chairman, Henry S. Fitch,
Theodore H. Eaton, Jr.
Volume 15, No. 6, pp. 251-295, 9 figs.
Published October 4, 1963
UNIVERSITY OF KANSAS
Lawrence, Kansas
PRINTED BY
JEAN M. NEIBARGER. STATE PRINTER
TOPEKA. KANSAS
1963
[Illustration: Union Label]
29-5936
A Revision of Snakes of the Genus Conophis
(Family Colubridae, from Middle America)
BY
JOHN WELLMAN
CONTENTS
PAGE
INTRODUCTION 253
ACKNOWLEDGMENTS 254
MATERIALS AND METHODS 254
GENUS Conophis Peters 255
Key to the Species and Subspecies 257
Analysis of Characters 257
Scutellation 258
Size and Proportions 258
Color Pattern 260
Sexual Dimorphism 260
_C. lineatus_ 262
_C. lineatus dunni_ 262
_C. lineatus lineatus_ 267
_C. lineatus concolor_ 270
_C. nevermanni_ 272
_C. pulcher_ 274
_C. vittatus_ 277
Skull 282
Dentition 288
Vertebrae 288
Hemipenes 289
Food and Feeding 289
Effect of Poison 290
TAXONOMIC RELATIONSHIPS AND EVOLUTION 291
SUMMARY 292
LITERATURE CITED 293
INTRODUCTION
Need for a comprehensive systematic review of the snakes of the genus
_Conophis_ was pointed out by Stuart (1954a, b). Since these snakes
appeared to be of zoogeographic importance in the Central American
region, I undertook the review as set forth on the following pages.
ACKNOWLEDGMENTS
For permission to examine specimens, and for information concerning
specimens in their care, I am grateful to Mr. L. C. Battersby and Miss
Alice G. C. Grandison, British Museum (Natural History); Mr. Charles
M. Bogert and Dr. Richard G. Zweifel, American Museum of Natural
History; Dr. Doris M. Cochran, United States National Museum; Prof.
William B. Davis, Agricultural and Mechanical College of Texas; Dr.
Josef Eiselt, Naturhistorisches Museums, Vienna; Prof. Norman Hartweg
and Prof. Laurence C. Stuart, Museum of Zoology, University of
Michigan; Dr. Robert F. Inger, Chicago Natural History Museum; Dr.
Alan E. Leviton, California Academy of Sciences; Mr. Edmond V.
Malnate, Academy of Natural Sciences, Philadelphia; Prof. George S.
Myers, Stanford University Natural History Museum; Mr. Wilfred T.
Neill, Ross Allen's Reptile Institute; Mr. Neil D. Richmond, Carnegie
Museum; Dr. William J. Riemer, University of Florida Collections;
Prof. Robert C. Stebbins, Museum of Vertebrate Zoology, University of
California; Prof. Hobart M. Smith, University of Illinois Natural
History Museum; and Dr. Ernest E. Williams, Museum of Comparative
Zoology, Harvard.
Prof. William E. Duellman supplied invaluable information and guidance
in my study. I am grateful to Prof. E. Raymond Hall for use of
facilities of the Museum of Natural History and editorial assistance.
I thank Prof. Laurence C. Stuart and Prof. Edward H. Taylor for
information and suggestions. My own field experience in Middle America
came as a result of assisting Professor Duellman in his own researches
supported by a grant from the National Science Foundation (NSF-G
9827). For these things I am deeply grateful. Specimens that I have
seen alive were collected by field companions Dale L. Hoyt and Jerome
B. Tulecke. Finally, I am grateful to my wife, Margaret L. Wellman,
for much help including typing much of the manuscript.
MATERIALS AND METHODS
Of the 325 specimens of the genus _Conophis_ available to me,
representing most of those in museum collections, scale counts were
made in the usual manner on 309. Ventrals were counted following the
system proposed by Dowling (1951:97-99); the anal plate was not
included. The anteroposterior position of the place where reduction
occurs in the number of the dorsal rows of scales is designated by
citing the number of the ventral scale directly beneath that place.
Measurements were taken to the nearest millimeter by means of a
millimeter stick. Body length is the distance from the tip of the
snout to the posterior edge of the anal plate; tail length, from the
latter point to the tip of the tail; and total length, the sum of the
body plus tail.
Descriptions of color are based on preserved specimens. Where
descriptions of the color of living individuals are given, the data
were taken from Kodachrome slides made available to me by William E.
Duellman. Due to the transient nature of the longitudinal dark stripes
in these snakes, no standard terminology has been devised, except that
the posterior continuations of the stripes which on the head pass
through the eye are termed lateral stripes; the posterior
continuations of the median stripe of the head are termed
dorsolateral stripes. A paravertebral stripe is one that is present
on the scale-row on either side of, but not including, the mid-dorsal
(vertebral) scale-row.
In order to reduce confusion in the discussion of variation, the
numbers designating the rows of dorsal scales are written as 1st, 2nd,
whereas the numbers designating the stripes are written as first,
second.
Except in three dried skeletons, teeth were counted on dentigerous
bones _in situ_. Since teeth are often missing, the sockets were
counted in order to obtain an accurate count.
In accounts of the species and subspecies, the observed range of
variation is followed by the mean in parentheses; in some instances
the mean is followed by the standard deviation, also in parentheses.
An example is 65-79 (70.6 +- 3.93).
Each synonymy includes all generic and specific combinations known to
me that have been used for the genus, and, in addition, references to
catalogues, checklists, and reports of collections.
Localities of occurrence that are not plotted on the distribution maps
are recorded in italic type under Specimens Examined. In the list of
Specimens Examined the localities and specimens are listed in the
following order: countries in alphabetical order; states or
departments in alphabetical order in each country; localities in
alphabetical order in each state or department; museum numbers in
numerical order after the abbreviations of names of museums. When more
than one specimen bears a single catalogue number, the number of
specimens is given in parentheses following the museum catalogue
number. Specimens for which data are given only as to country or to
state or department are listed first after the name of that political
unit under "no specific locality."
The abbreviations for the museum collections are:
AMNH American Museum of Natural History
ANSP Academy of Natural Sciences of Philadelphia
BMNH British Museum (Natural History)
CAS California Academy of Sciences
CNHM Chicago Natural History Museum
ERA-WTN E. Ross Allen-Wilfred T. Neill, Ross Allen's Reptile Institute
KU University of Kansas Museum of Natural History
MCZ Museum of Comparative Zoology, Harvard
MVZ Museum of Vertebrate Zoology, University of California
NMW Naturhistorisches Museums Wien, Vienna
SU Stanford University Natural History Museum
TCWC Texas Cooperative Wildlife Collection, Agricultural and
Mechanical College of Texas
UF University of Florida Collections
UIMNH University of Illinois Museum of Natural History
UMMZ University of Michigan Museum of Zoology
USNM United States National Museum
Family COLUBRIDAE
Subfamily Xenodontinae
Genus =Conophis= Peters
_Tomodon_ (part) Dumeril, Bibron and Dumeril, Erpetologie Generale,
7(pt.2):936, February 7(pt.2):936, February 25, 1854 (_lineatus_
and _vittatus_); Salvin, Proc. Zool. Soc. London, 28:455, 1860
(_pulcher_).
_Psammophis_ (part), Guenther, Catalogue of Colubrine Snakes in
the Collection of the British Museum, London, 1858:135
(_lineatus_).
_Conophis_ Peters, Monatsb. Akad. Wiss. Berlin, 1860:519-520,
pl., fig. 3 (_vittatus_); Cope, Proc. Acad. Nat. Sci.
Philadelphia, 13:300, December 28, 1861 (_lineatus concolor_);
Proc. Acad. Nat. Sci. Philadelphia, 18:318-319, February 20,
1867 (_lineatus concolor_); Proc. Acad. Nat. Sci.
Philadelphia, ser. 2, 8:137, 1876 (_pulcher_); Bocourt in
Dumeril, Bocourt and Mocquard, Mission Scientifique au Mexique
et dans l'Amerique Centrale, 2:643-644, pl. 38, fig. 5, 1886
(_lineatus lineatus_); Cope, Proc. Amer. Philos. Soc., 23:489,
October 28, 1886; Hoffmann, Klassen und Ordnungen des
Thier-Reichs. Reptilien. Bd. 6, 3:1707, 1890; Cope, Trans.
Amer. Philos. Soc., 18:207, April 15, 1895; Dunn, Bull.
Antivenin Inst. Amer., 2(1):21, 24, April, 1928; Copeia, no.
4:214, December 31, 1937 (_nevermanni_).
_Tachymenis_ (in part), Garman, Bull. Essex Inst., 16:33,
January 9, 1884 (_vittatus_ and _lineatus_).
_Erythrolamprus_ (in part), Ditmars, Bull. Antivenin Inst.
Amer., 2(2):27-29, June.
_Coniophanes_ (in part), Wettstein, Sitz. Akad. Wiss. Wien,
mathem-naturw. kl. 143:37-38, 1934 (_nevermanni_).
_Historical summary._--In 1854 Dumeril, Bibron and Dumeril described
and figured _Tomodon lineatum_ from America. In 1860 Peters described
and figured as a new genus and species, _Conophis vittatus_, based on
a specimen that he had obtained from a dealer in Hamburg. The
provenance of this specimen is not known, for it was discovered aboard
a ship near the mouth of the Mississippi River. It was not until 1871
that Cope included _lineatus_ in the genus _Conophis_. Cope (1861)
proposed the name _Conophis vittatus_ (_nec_ Peters, 1860). Later
(1900) he changed its name to _Conophis lineaticeps_. Early
uncertainty of the relationships of the species _lineatus_ caused
Guenther (1858) to place it in the genus _Psammophis_. With the
exception of Garman (1884a and 1884b) who placed _lineatus_ in the
genus _Tachymenis_, and Wettstein (1934) who reported five specimens
of _Conophis nevermanni_ as _Coniophanes i. imperialis_, all specimens
reported after 1876 were placed in the genus _Conophis_.
The only previous attempt to review the systematics of this genus was
made by Smith (1941) who based his study primarily on specimens in the
United States National Museum. He examined only 28 specimens,
including none of one species (_nevermanni_).
_Description._--Hemipenis slightly bifurcate having forked sulcus
spermaticus, large spines near base, and smaller spines or papillae on
flounces nearer apices; prediastemal maxillary teeth 8-12, subequal in
length, and followed by short diastema and one enlarged fang or two;
fangs grooved, only one functional at any one time, unless snake is in
process of shedding teeth; teeth 6-10 on palatine, 15 to 19 on
pterygoid, 15 to 21 on dentary; teeth on dentary decreasing in size
posteriorly; large parotid (venom) gland on either side of head in
temporal region; head shields of basically unmodified colubrid type
excepting decurved rostral; rostral concave below and therein modified
for burrowing; internasals and prefrontals paired; nasals divided;
loreal single; preocular one, rarely two; postoculars, two;
supralabials, 7-8, 3rd and 4th or 4th and 5th under eye; infralabials,
8-11, usually 9 or 10; temporals, normally 1 plus 2 plus 3;
chin-shields subequal in length; ventrals, 149-183, rounded and
overlapping; caudals, 55-89, paired and imbricate; anal divided;
dorsal scales smooth and in 19 rows at mid-body with no apical pits
or keels; scale reduction normally involving fusion of 3rd and 4th
rows, resulting in 17 scale-rows near tail; tail length more than 20
per cent of body length; maximum total length exceeding 1.1 meters;
dorsal color pattern consisting of dark stripes, or no darkening, on
paler ground-color; ventral surfaces immaculate pale yellowish or
white, except on specimens having single lateral dark spots on some or
all ventrals; pupil round; diurnal or crepuscular; feeding primarily
on small lizards, sometimes on small mammals or other snakes.
_Distribution._--Semi-arid regions of southern Mexico and Central
America as far south as Costa Rica.
KEY TO THE SPECIES AND SUBSPECIES
Although many juveniles differ greatly in general coloration from the
adults, both the juveniles and the adults of any species or subspecies
can be identified from the following key; juveniles differ from adults
in extent and intensity of dark pigmentation but not in rows of scales
involved.
1. Seven supralabials (3rd and 4th below orbit); 3 to 8 dark
stripes along body 2
Eight supralabials (4th and 5th below orbit); unstriped or with
more than 4 dark stripes along body, or dark with 2 or 4 pale
stripes 3
2. Dark stripes involving no more than one longitudinal
scale-row _C. lineatus lineatus_ (part), p. 267
Dark stripes involving at least two adjacent scale-rows
_C. vittatus_, p. 277
3. Supralabials having black borders above; head and body
generally black with 2 or 4 white lines running length
of body _C. nevermanni_, p. 272
Supralabials immaculate or having dark borders below; head
and body usually pale with dark stripes, or without stripes 4
4. Lateral dark stripe through eye involving upper half of second
scale-row; dark stripe on paravertebral row, at least
posteriorly _C. pulcher_, p. 274
Lateral dark stripe becoming indistinct on body, or restricted
to 4th or 3rd and 4th rows anteriorly, not involving 2nd
scale-row on anterior 1/3 of body (an auxiliary lateral stripe
sometimes present involving 2nd row); no paravertebral stripes 5
5. Stripes disappearing posteriorly (except for small spots of
pigment on scale-row 4 or 7); 1st scale-row unpigmented
_C. lineatus concolor_, p. 270
Stripes present posteriorly; 1st scale-row pigmented 6
6. Lateral stripes narrow on nape, restricted to 4th scale-row
on body _C. lineatus lineatus_ (part), p. 267
Lateral stripes involving 3rd and 4th rows, at least on
nape _C. lineatus dunni_, p. 262
Analysis of Characters
Characters showing inter-specific and intra-specific variation and
that have a wide range of variation were analyzed statistically, when
possible, in order to determine extent of variation. One character
(see table 3) was analyzed for sexual dimorphism, and for it the
coefficient of difference is also given. The statistical terms and
formulae have been adopted from Mayr, Linsley and Usinger (1953).
Dorsal head shields varied individually and were of no taxonomic
importance. Osteological and hemipeneal characters did not show enough
variation to be considered here.
Scutellation
Labials, dorsals, ventrals, and subcaudals were the most useful
scales.
_Labials._--All species usually have eight supralabials except _C.
vittatus_, which has seven. The only other population having a
relatively high frequency of occurrence of seven supralabials is _C.
l. lineatus_. In specimens having eight supralabials, the fourth and
fifth enter the orbit; in specimens having seven supralabials, the
third and fourth enter the orbit (the second and third are fused).
Usually there are ten infralabials, sometimes nine or eleven;
specimens having seven supralabials usually have nine infralabials,
sometimes eight, rarely ten.
_Dorsals._--Although there is no variation in the number of rows of
dorsal scales, there is some in the method of scale reduction. There
are 19 rows of dorsal scales from close behind the head to about
midway on the body where two rows are lost, leaving 17 rows from there
to near the base of the tail. This reduction is accomplished by fusion
of the scales of the 3rd and 4th rows or sometimes by the dropping out
of the 3rd row. The place at which reduction occurs in number of
dorsal scales in relation to the ventral (scale) directly below is
highly variable and of little taxonomic importance (table 1).
TABLE 1.--VARIATION IN THE PLACE OF DOSAL SCALE REDUCTION IN CONOPHIS.
Key to Columns
====================================
Std. Dev. = Standard Deviation
Std. Err. = Standard Error
Coe. Var. = Coefficient of Variation
==============+===========+========+=======+======+======+======
| Number of | | | Std. | Std. | Coe.
Taxon | Specimens | Range | Mean | Dev. | Err. | Var.
--------------+-----------+--------+-------+------+------+------
_l. concolor_ | 45 | 89-114 | 102.5 | 5.57 | 0.83 | 5.43
_l. dunni_ | 36 | 91-111 | 102.1 | 4.59 | 0.77 | 4.50
_l. lineatus_ | 26 | 91-107 | 100.2 | 3.59 | 0.72 | 3.58
_nevermanni_ | 6 | 84- 97 | 93.2 | 4.71 | 1.92 | 5.05
_pulcher_ | 26 | 94-119 | 104.6 | 4.90 | 0.96 | 4.68
_vittatus_ | 170 | 84-118 | 102.3 | 6.60 | 0.16 | 6.45
--------------+-----------+--------+-------+------+------+------
_Ventrals._--The number of ventral scutes varies from 149-183, and
shows no significant variation in the means (table 2).
_Subcaudals._--The number of subcaudal scutes varies from 55 to 89. In
some populations there is no overlap in the range of variation of
males and females. The total variation and sexual dimorphism are
analyzed in table 3.
Size and Proportions
Although considerable variation in size is observable, little
taxonomic use is made of size since sufficient series are not
available to determine age classes. The subspecies attaining the
largest size is _C. lineatus concolor_; all others are smaller and of
about the same size and proportions. The longest specimen, a male of
_C. l. concolor_, has a body length of 893 mm., a tail length of 274
mm., and a total length of 1167 mm.
TABLE 2.--VARIATION IN THE NUMBER OF VENTRALS IN CONOPHIS.
Key to Columns
====================================
Std. Dev. = Standard Deviation
Std. Err. = Standard Error
Coe. Var. = Coefficient of Variation
==============+===========+=========+=======+======+======+======
| Number of | | | Std. | Std. | Coe.
Taxon | Specimens | Range | Mean | Dev. | Err. | Var.
--------------+-----------+---------+-------+------+------+------
_l. concolor_ | 45 | 158-170 | 163.7 | 1.56 | 0.23 | 0.95
_l. dunni_ | 36 | 159-178 | 167.2 | 4.56 | 0.76 | 2.72
_l. lineatus_ | 26 | 157-169 | 163.5 | 3.59 | 0.72 | 2.20
_nevermanni_ | 6 | 173-183 | 176.5 | 4.00 | 1.63 | 2.27
_pulcher_ | 26 | 149-180 | 169.5 | 5.31 | 1.04 | 3.13
_vittatus_ | 171 | 149-180 | 163.7 | 6.33 | 0.15 | 3.87
--------------+-----------+---------+-------+------+------+------
TABLE 3.--SEXUAL DIMORPHISM AS INDICATED BY VARIATION IN THE NUMBER OF
SUBCAUDALS IN CONOPHIS.
Key to Columns
====================================
Num. Spc. = Number of Specimens
Std. Dev. = Standard Deviation
Std. Err. = Standard Error
Coe. Var. = Coefficient of Variation
Coe. Dif. = Coefficient of Difference
====================+=====+====+=======+======+======+======+======+=====
| |Num.| | | Std. | Std. | Coe. | Coe.
Taxon | Sex |Spc.| Range | Mean | Dev. | Err. | Var. | Dif.
--------------------+-----+----+-------+------+------+------+------+-----
_lineatus concolor_ | [M] | 22 | 68-74 | 70.3 | 2.14 | 0.46 | 3.04 |
| | | | | | | | 1.97
| [F] | 16 | 56-65 | 61.8 | 2.18 | 0.55 | 3.53 |
| | | | | | | |
_lineatus dunni_ | [M] | 14 | 67-80 | 74.5 | 3.86 | 1.03 | 5.18 |
| | | | | | | | 0.95
| [F] | 16 | 60-72 | 67.1 | 3.91 | 0.97 | 5.82 |
| | | | | | | |
_lineatus lineatus_ | [M] | 11 | 67-73 | 69.8 | 6.17 | 1.85 | 8.84 |
| | | | | | | | 0.60
| [F] | 9 | 60-66 | 62.4 | 6.17 | 2.06 | 9.89 |
| | | | | | | |
_nevermanni_ | [M] | 3 | 82-89 | 85.3 | .... | .... | .... |
| | | | | | | | ....
| [F] | 2 | 71-76 | 73.5 | .... | .... | .... |
| | | | | | | |
_pulcher_ | [M] | 7 | 70-79 | 74.3 | 3.11 | 1.17 | 4.19 |
| | | | | | | | 0.93
| [F] | 11 | 65-71 | 68.2 | 3.42 | 1.08 | 5.01 |
| | | | | | | |
_vittatus_ | [M] | 95 | 59-76 | 67.8 | 3.33 | 0.34 | 4.91 |
| | | | | | | | 1.28
| [F] | 58 | 55-66 | 60.0 | 2.75 | 0.36 | 4.58 |
--------------------+-----+----+-------+------+------+------+------+-----
Color Pattern
This is the primary feature used to separate species and subspecies in
this genus. The color pattern consists of three black or deep brown
stripes on the dorsal part of the head, one mid-dorsally, and one on
each side of the head passing through the eye. On the body, there are
usually dark longitudinal stripes on a pale tan or white background.
There may be as few as three in _vittatus_, and as many as 13 in _l.
dunni_; except that there is none in _C. l. concolor_. There are two
pairs of primary dark stripes. The first is the body stripe that is
the posterior extension of the stripe which on the head passes through
the eye and is termed the lateral stripe. The other primary stripe is
the posterior continuation of the mid-dorsal head stripe. Usually it
is split into two dorsolateral stripes on the body. Stripes may be
present on the scale-row to either side of the primary stripe. These
stripes are usually dark brown or black and are the secondary stripes.
Finally, additional stripes may be present that are paler brown and
bear no direct relationship to the primary stripes. These are
auxiliary stripes.
Every stripe originates either as broad continuous stripe or as a row
of spots or dashes, forming a discontinuous stripe, which in some
specimens becomes continuous posteriorly. The stripes are usually
black or deep brown, although auxiliary stripes are sometimes paler.
The dorsal ground color is pale brown, tan, olive, or white; usually
the ground color is palest ventrally and darkest dorsally.
In some specimens of _Conophis_ the lateral tips of the ventrals are
spotted, one spot on each end of each ventral. Otherwise, the ventrals
are immaculate white.
In some species there is considerable ontogenetic change in color
pattern, although the juveniles bear the basic color characteristics
of the adults. For example, juveniles of the sympatric species _C.
lineatus dunni_ and _C. pulcher_ can be separated on the basis of
which scale-rows are darkly pigmented. _C. l. dunni_ has eight stripes
in juveniles and as many as 13 in adults. Juveniles show a greater
contrast between the black stripes and the pale ground color than do
adults. With increased age (size) the stripes in some populations
become paler and are split; simultaneously the ground color becomes
darker.
Sexual Dimorphism
Sexual dimorphism is evident in all species and subspecies of
_Conophis_. Differences always exist in the number of subcaudals and
in the tail/body ratio; males have more subcaudals and relatively
longer tails than do females (table 3). Otherwise, there is little
sexual dimorphism in these snakes. Males and females cannot be
differentiated by any feature of coloration.
Formulation of a biological concept of the species as defined by Mayr
(1942) is difficult when most of the data primarily relied upon are
from preserved specimens. Nevertheless, a total view of variation was
attempted so that differences within and between populations could be
recognized. Differences, between populations, that seem to be part of
a continuous or internal cline (Huxley, 1942) are not used for
characterizing subspecies.
[Illustration: FIG. 1. Patterns of dorsal coloration at
mid-body of adults of all species and subspecies of the genus
_Conophis_ except _C. lineatus concolor_. A. _C. lineatus
dunni_ (UMMZ 107339) from Santa Rosa, Guatemala. B. _C.
lineatus dunni_ (UMMZ 116537) from 1.5 mi. N Matagalpa,
Nicaragua. C. _C. lineatus dunni_ (ANSP 3480) from "San Jose,"
Costa Rica. D. _C. l. lineatus_ (KU 23253) from Rio Blanco,
20 km. WNW Piedras Negras, Veracruz, Mexico. E. _C. nevermanni_
(ANSP 22424) "San Jose," Costa Rica. F. _C. pulcher_ (UIMNH
33646) from Soconusco, Chiapas, Mexico. G. _C. vittatus_ (KU
39626) from Atencingo, Puebla, Mexico. H. _C. vittatus_ (TCWC
9473) from 1 mi. S Colotlipa, Guerrero, Mexico. I. _C.
vittatus_ (UMMZ 82653) from "vicinity of" Salina Cruz, Oaxaca,
Mexico. Approximately x 3/4.]
=Conophis lineatus= (Dumeril, Bibron and Dumeril)
_Tomodon lineatum_ (in part) Dumeril, Bibron and Dumeril,
Erpetologie Generale, 7(pt. 2):936-938, February 25, 1854.
_Diagnosis._--No dark pigmentation posterior to nape; lateral dark
stripe anteriorly passing through eye and posteriorly involving 4th or
3rd and 4th scale-rows only; first scale-row darkly pigmented; no
paravertebral dark stripe; six to thirteen (or no) dark stripes at
mid-body; usually eight (sometimes seven) supralabials immaculate
white or having dark ventral margins.
_Variation._--The variation in this species is discussed more
completely in the descriptions of the subspecies. One hundred and
seven specimens have 157 to 178 (164.8) ventrals. Eighty-eight of
these snakes having complete tails have 56 to 80 (68.0) subcaudals;
the number of ventrals plus subcaudals varies from 222 to 247 (233.5)
in 87 of these. On 107 specimens the reduction from 19 to 17 dorsal
scale-rows takes place between ventrals 89 and 114 (101.8). Sexual
dimorphism is evident in the number of subcaudals; there are, on the
average, fewer subcaudals in females than in males of each subspecies.
The largest specimen is a male _C. l. concolor_ (USNM 46345) from
Chichen Itza, Yucatan, Mexico, having a body length of 893 mm., a tail
length of 274 mm. and a total length of 1167 mm. The smallest is a
juvenile _C. l. dunni_ (MCZ 49749) from Tegucigalpa, Honduras, having
a body length of 162 mm., a tail length of 51 mm. and a total length
of 213 mm.
The greatest variation is in coloration. Dark color, or lack thereof,
has been used to separate the subspecies of _C. lineatus_. The
ground-color is pale brown, pale olive or white, either with no
stripes on the body or with eight to thirteen dark stripes at
mid-body. Specimens having dark stripes on the body always have black
or dark brown pigmentation on the first, 4th and 7th dorsal
scale-rows. In some there is dark pigmentation on the 2nd, 3rd, 8th
and 10th rows of scales. The stripes appear on the nape or farther
posteriorly, usually on the anterior third of the body, either as a
series of spots or dashes that form a continuous stripe farther
posteriorly or as a continuous stripe.
The ventrals usually have more or less conspicuous dark spots
laterally on those specimens having dark stripes present on the
dorsum; spots are absent on all specimens having no dorsal stripes and
on some specimens having dorsal stripes. Except for the dark lateral
spots (when present) the ventrals are immaculate white. Usually the
dorsal ground-color is pale tan, especially on the striped forms. The
ground-color is usually palest on the lower dorsal scale rows and
darkest dorsally.
Three populations are separable as subspecies; one has no stripes on
the body and occurs in the Yucatan Peninsula. The other two have
stripes on the dorsum and vary clinally in coloration from the north
(Veracruz, Mexico) to south (Costa Rica) (Fig. 2). Reasons for
separating these widespread, variable snakes into two subspecies are
that they are discontinuous in distribution (the population in
Veracruz is disjunct from the one that extends from Guatemala to Costa
Rica), and that these populations have distinctly different color
patterns.
[Illustration: FIG. 2. Selected locality records for the
subspecies of _Conophis lineatus_.]
=Conophis lineatus dunni= Smith
_Psammophis lineatus_, Guenther, Catalogue of Colubrine Snakes
in the Collection of the British Museum, p. 135, 1858.
_Conophis lineatus_, Cope, 3rd Ann. Rept. Peabody Acad. Sci.,
p. 82, 1871; Proc. Acad. Nat. Sci. Philadelphia, 23:204,
October 24, 1871; Journ. Acad. Nat. Sci. Philadelphia, ser. 2,
8:137, 1876; Bull. U. S. Natl. Mus., 32:77, 1887; Guenther,
Biologia Centrali-Americana, p. 165, March, 1895; Boulenger,
Catalogue of the Snakes in the British Museum (Natural
History), 3:122-123, 1896; Werner, Arch. Naturges., 90, abt. A,
12:143, 1925; Schmidt, Zool. Ser. Field Mus. Nat. Hist.,
12:199-200, November 21, 1928; Amaral, Mem. Inst. Butantan,
4:212, 1929; Werner, Zool. Jahrb., 57:184, 1929; Stuart, Occas.
Papers Mus. Zool. Univ. Michigan, 292:5, June 29, 1934; Dunn,
Copeia, no. 4:214, December 31, 1937.
_Conophis lineatus similis_ Smith, Journ. Washington Acad.
Sci., 31:123-124, March 15, 1941 (Type.--United States National
Museum, No. 79963; type locality.--Managua, Nicaragua; _nec_
Bocourt _in_ Dumeril, Bibron and Mocquard, Mission Scientifique
au Mexique et dans l'Amerique Centrale, 2:647-648, 1886);
Cochran, Bull. U. S. Natl. Mus., 220:167, 1961.
_Conophis lineatus dunni_ Smith, Proc. U. S. Natl. Mus.
92:394-395, November 5, 1942; Savage, Trans. Kansas Acad. Sci.,
50:483-486, December 31, 1949; Taylor, Univ. Kansas Sci. Bull.,
34(pt. 1):145, October 1, 1951; Neill and Allen, Publ. Res.
Div. Ross Allen's Rept. Inst., 2:56, November 10, 1959;
Herpetologica, 16:146-148, fig. 2, September 23, 1960.
_Conophis pulcher pulcher_, Stuart, Misc. Publ. Mus. Zool.
Univ. Michigan, 69:79, June 12, 1948; Contr. Lab. Vert. Biol.
Univ. Michigan, 45:24, May, 1950; Contr. Lab. Vert. Biol.
Univ. Michigan, 49:14, August, 1951; Contr. Lab. Vert. Biol.
Univ. Michigan, 65:19-20 (part), March, 1954.
_Conophis pulcher plagosus_, Mertens, Zool. Anz., 148:93,
February, 1952; Abhand. Senken. Naturw. Gesell., 487:61-62,
December 1, 1952.
_Conophis lineatus nevermanni_, Taylor, Univ. Kansas Sci.
Bull., 37(pt. 1):563-565, fig. 16, October 15, 1955.
_Type._--United States National Museum, no. 79963, obtained by Lt. H.
C. Kellers. Type locality: Managua, Nicaragua. There are also three
paratypes; one a topotype (USNM 79964), one from "Nicaragua" (USNM
25237), and one from Esparta, Costa Rica (USNM 37758).
_Diagnosis._--Lateral dark stripe anteriorly passing through eye and
posteriorly involving 3rd and 4th scale-rows; 1st scale-row darkly
pigmented; no paravertebral dark stripe, although vertebral row
sometimes darkly pigmented; six to thirteen stripes at mid-body; eight
supralabials immaculate or having dark ventral margins.
_Variation._--Thirty-six specimens have 159 to 178 (167.2 +- 4.56)
ventrals. Thirty of these snakes having complete tails have 60 to 80
(70.5 +- 5.36) subcaudals; the number of ventrals plus subcaudals
varies from 224 to 247 (237.6). In 36 specimens the reduction from 19
to 17 dorsal scales takes place between ventrals 91 and 111 (102.1 +-
4.59). Sexual dimorphism is evident in the number of subcaudals; 16
females have 60 to 72 (67.1), and 14 males have 67 to 80 (74.5)
subcaudals. The largest specimen (ERA-WTN BH-300) is a female from
Augustine, British Honduras, having a body length of 732 mm., a tail
length of 183 mm. and a total length of 915 mm. A juvenile (MCZ 49794)
from Tegucigalpa, Honduras, has a body length of 162 mm., a tail
length of 51 mm. and a total length of 213 mm.
The greatest variation is in coloration. The ground-color is pale
brown or white with dark stripes of black or deep brown present
dorsally and laterally. Some specimens from Costa Rica have as many as
13 dark stripes at mid-body (fig. 1, C). In these snakes the first
row of dorsal scales bears a series of large, slightly elongated, dark
spots; on the 2nd row a narrow dark brown stripe on the middle of the
scales; on the 3rd a black stripe on the dorsal one-third to one-half
of the scales; on the 4th and the 7th rows black stripes on the medial
half of the scales of each row; on the 8th and 10th (vertebral) rows
dark brown stripes on the medial third of the scales of each row. A
specimen from Guatemala (UMMZ 107339) shows the greatest reduction of
stripes and dark pigmentation (fig. 1, A); it has only eight stripes
at mid-body: on the first row of dorsal scales a discontinuous stripe
is formed by a series of dashes; the 3rd row bears a series of small
black spots near the base and tip of each scale; the 4th and 7th rows
bear continuous black stripes on the medial third to fourth of the
scales of each row; the 8th row has extremely small dark spots near
the tips of some scales.
The primary stripes, characteristic of the species _lineatus_, are
those on the 1st, 4th and 7th rows of dorsal scales; these are the
most prominent stripes. In some specimens these primary stripes begin
as spots or dashes on the nape and become continuous stripes
posteriorly; in others they are continuous for the length of the body.
The stripe on the 1st row is most variable; usually it consists of
only a discontinuous series of dashes for most of its length. The
secondary stripes are those on the 3rd and 8th rows; of these, only
the one on the 3rd scale-row is present on the nape. The stripe on the
3rd row in combination with the dark stripe on the 4th row is the
posterior continuation of the dark stripe that on the head passes
through the eye; this stripe is characteristic of _C. lineatus dunni_.
Both secondary stripes usually begin anteriorly as a series of spots
or dashes and become continuous stripes posteriorly; occasionally near
the base of the tail they fuse with the primary stripes on the 4th and
7th rows. In some specimens in Costa Rica indistinct stripes are
present on the 10th (posteriorly the 9th) rows, and in some specimens
in Honduras, Nicaragua, and Costa Rica similar indistinct stripes are
present on the 2nd row.
Usually there are more or less conspicuous dark spots laterally on the
ventrals, but in some specimens there are no spots. Except for the
dark lateral spots (when present) the ventrals are immaculate white.
The dorsal ground-color is a pale brown or brownish white in preserved
specimens on the 1st, 2nd, 3rd and 4th rows of scales where dark
stripes or spots are not present. The ground-color of the dorsum
between the 5th rows on each side is a somewhat darker shade of pale
to medium brown.
Never is more than the lower one-third of each of the supralabials
brown. In many specimens little or no brown is present on the lower
margins of these scales. Some of the specimens having brown on the
supralabials also have dusky markings of tan or gray on the chin and
infralabials. Specimens from the northern part of the range
(Guatemala) less frequently have dark chins and supralabials than do
specimens from the southern part of the range (Costa Rica). There is,
nevertheless, at any one locality considerable variation in the amount
of dark pigmentation present on the chin and supralabials, thereby
indicating that the slight geographic trend in this character is not
significant.
Probably the most common pattern of dorsal coloration consists of
eight or ten dark stripes (fig. 1, B). In snakes having this pattern
the stripes on the 1st, 3rd, 4th and 7th rows are always present and
prominent, although those on the 1st and 3rd rows sometimes are
present as discontinuous rows of dashes. The ground-color from the
venter to the 7th row is usually pale brown, and that dorsally between
the 7th rows on each side is usually a darker, medium brown. A series
of spots or dashes or a continuous stripe is sometimes present on the
8th row of scales.
Snakes having a larger number of dark stripes and more dark
pigmentation occur in the southern part of the range. There seems to
be a cline from paler snakes having fewer stripes in the north to
darker snakes in the south.
[Illustration: FIG. 3. Patterns of dorsal coloration at
mid-body of juveniles of two sympatric species of _Conophis_.
A. _C. lineatus dunni_ (MCZ 49794) from Tegucigalpa, Honduras.
B. _C. pulcher_ (MCZ 49791) from Tegucigalpa, Honduras.
Approximately x 1.]
In juveniles, there are six or eight black stripes boldly contrasting
with a white or pale tan ground-color (fig. 3, A). The first pair of
stripes is on the 1st scale-row; the second pair, on the 3rd and 4th
scale-rows; the third pair, on the 7th row; the fourth pair (when
present), on the 8th row. Ontogenetic change in coloration consists of
the splitting of the second pair of dark stripes in the juvenile.
Additional stripes may form later on the 2nd and/or 10th rows of
dorsal scales.
_Remarks._--Savage (1949:483-486) stated that his specimen of _C. l.
dunni_ (from Honduras) resembled _l. lineatus_ in having secondary
stripes on the 2nd and 8th rows and dark pigmentation throughout the
length of the 2nd row. As can be seen from the preceding discussion of
variation, a specimen having this color pattern is clearly within the
observed range of variation of _l. dunni_. The specimen in no way
represents an intergrade between _C. l. dunni_ and _l. lineatus_.
A specimen in the British Museum (Natural History), catalogued in 1853
(no. 53.2.4.16), has the locality listed as "Mexico." Since this
specimen is of _C. l. dunni_ and this subspecies occurs only south of
Mexico, the locality must be considered erroneous; possibly the
locality as recorded referred only to the fact that the specimen came
from tropical Middle America.
The absence of paravertebral stripes, the presence of a lateral
dark stripe on the nape involving the 3rd and 4th rows of scales,
and the darkly pigmented 1st scale-row, in combination with the
characteristics of the genus, distinguish _C. l. dunni_ from all other
snakes in Mexico and Central America. The only sympatric species of
this genus, _C. pulcher_, differs in that it has paravertebral stripes
(though never a vertebral dark stripe). _Conophis pulcher_ has a
lateral dark stripe that includes the upper half of the second
scale-row on the anterior part of the body; stripes of _C. l. dunni_
never include more than the 3rd and 4th rows. Even as juveniles the
paravertebral row is not darkly pigmented in _C. l. dunni_ as it is in
_C. pulcher_.
_Distribution._--Semi-arid habitats from sea level to elevations of
1000 m. from the Cuilco Valley in western Guatemala, El Peten and
British Honduras southeastward to northeastern and southern Honduras,
western Nicaragua and northwestern Costa Rica (fig. 2).
_Specimens examined._--Total of 41 specimens, as follows: BRITISH
HONDURAS: _Cayo District_: Augustine, ERA-WTN BH-300; _Mountain Pine
Ridge, 10 mi. E Augustine_, ERA-WTN BH-298.
COSTA RICA: _no specific locality_, AMNH 17309. "_Cartago_," BMNH
71.11.22.15. _Puntarenas_: 32 km. N Barranca, KU 35630; Esparta, USNM
37758. "_San Jose_," ANSP 3480, 12232.
EL SALVADOR: _Morazan_: El Divisadero, CNHM 10999. _San Miguel: San
Pedro_, MCZ 57061.
GUATEMALA: _El Peten_: Sojio (Toocog), AMNH 69969, 69986.
_Huehuetenango_: flood plain Rio Cuilco, W of Finca Canibal, 18 km. N
Tacana, UMMZ 98283. _Santa Rosa_: Santa Rosa, UMMZ 107339.
HONDURAS: _no specific locality_, AMNH 32814, UF 7657. _Cortes:
Cofradia_, SU 8422; _Gracias_, CNHM 28560; _Hacienda de Santa Ana, W
San Pedro Sula_, CNHM 5297; San Pedro Sula, UMMZ 68695(2); _near San
Pedro Sula_, MCZ 27563. _Francisco Morazan: Potrero de Melio, Escuela
Agricola Pan-americana_, MCZ 49987; Tegucigalpa, MCZ 49784, 49786,
49789-90, 49792, 49794.
MEXICO: _no specific locality_, BMNH 53.2.4.16.
NICARAGUA: _no specific locality_, UMMZ 65633, USNM 25237. _Leon_: El
Polvon, MCZ 5645, 5696. _Managua_: Managua, USNM 79963-64; _3 mi. SW
Managua_, KU 42315; _8 mi. WNW Managua_, KU 42314; _1 mi. N Sabana
Grande_, KU 42311-13. _Matagalpa_: 1.5 mi. N Matagalpa, UMMZ 116537.
=Conophis lineatus lineatus= (Dumeril, Bibron and Dumeril)
_Tomodon lineatum_ (in part) Dumeril, Bibron and Dumeril,
Erpetologie Generale, 7(pt. 2):936-938, atlas, pl. 73,
February 25, 1854; Bocourt, Journ. de Zool., 5:406-407, 1876.
_Tomodon lineatus_, Jan, Arch. Zool. Anat. Fis., Genoa,
2(2):234, March 1863; Elenco sistematico degli ofidi. Milano,
p. 57, 1863; Muller, Reisen in den Vereinigten Staaten,
Canada, und Mexico. Bd. 3. Beitrage zur Geschichte, Statistik,
und Zoologie von Mexiko. 3:607, 1865; Jan and Sordelli,
Iconographie Generale des Ophidiens, Milano. liv. 19, pl. 6,
fig. 3, December, 1866; liv. 50, pl. 2, fig. 34, November,
1881.
_Tachymenis lineata_ (in part), Garman, Bull. Essex Inst., 16:
33, January 9, 1884; Mem. Mus. Comp. Zool., 8:60-61, July,
1884.
_Conophis lineatus_, Bocourt _in_ Dumeril, Bocourt and
Mocquard, Mission Scientifique au Mexique et dans l'Amerique
Centrale, 2:643-644, pl. 38, fig. 5, 1886; Cope, Trans. Amer.
Philos. Soc., 18:218, pl. 28, fig. 2, (hemipenis), April 15,
1895; Boulenger, Catalogue of the Snakes in the British Museum
(Natural History), 3:122-123 (part), 1896; Cope, Ann. Rept. U.
S. Natl. Mus. for 1898, pp. 1094-1095, 1242, pl. 26, fig. 2,
(hemipenis), 1900; Amaral, Mem. Inst. Butantan, 4:212, 1929;
Mittleman, Copeia, no. 2:122, June 30, 1944.
_Conophis lineatus lineatus_, Smith, Journ. Washington Acad.
Sci., 31:122, March 15, 1941; Proc. U. S. Natl. Mus., 92:395,
November 5, 1942; Proc. U. S. Natl. Mus., 93:407, October 29,
1943; Smith and Taylor, Bull. U. S. Natl. Mus., 187:43,
October 5, 1945; Shannon and Smith, Trans. Kansas Acad. Sci.,
52:505, December 31, 1949; Smith and Taylor, Univ. Kansas Sci.
Bull., 33(pt. 2):351, March 20, 1950; Werler and Smith, Texas
Journ. Sci. 4(4):565, December 30, 1952; Fugler and Dixon,
Herpetologica, 14:186, December 1, 1958.
_Type._--Museum National d'Histoire Naturelle, Paris, no. 3738. Type
locality.--"Mexico," restricted to Veracruz, Veracruz, Mexico, by
Smith and Taylor (1950:351). Little is known about the type specimen,
and nothing, concerning its collector or the locality at which it was
collected. Smith (1941:122) assumed that the specimen illustrated by
Bocourt in Dumeril, Bocourt, and Mocquard (1886:pl. 38, fig. 5) was
the type of _C. l. lineatus_. I have also made this assumption
concerning the identity of the type specimen of this species,
especially because of the many inconsistencies appearing in the plate
accompanying the description by Dumeril, Bibron and Dumeril (1854:pl.
73), and by Jan and Sordelli (1866:pl. 6). Neither show the nape nor a
regular number of dorsal scales by which accurate determination of
color pattern can be made and by means of which _C. l. dunni_ and _C.
l. lineatus_ can be separated.
_Diagnosis._--Lateral dark stripe anteriorly passing through eye and
posteriorly involving fourth scale-row only; first scale-row darkly
pigmented; no paravertebral stripe; no dark pigment on vertebral row;
six or eight dark stripes at mid-body, secondary stripes often present
posteriorly; usually eight (sometimes seven) supralabials immaculate
or having dark ventral margins.
_Variation._--Twenty-six specimens have 157 to 169 (163.5 +- 3.59)
ventrals. Twenty of these snakes having complete tails have 60 to 73
(66.5 +- 4.26) subcaudals; the number of ventrals plus subcaudals
varies from 224 to 238 (230.1) in nineteen of these. In 26 specimens
the reduction from 19 to 17 dorsal scale-rows takes place between
ventrals 91 and 107 (100.2 +- 3.59). Sexual dimorphism is evident in
the number of subcaudals; nine females have 60 to 66 (62.4), and 11
males have 68 to 73 (69.8) subcaudals. The largest specimen (AMNH
19643) is a male from "Mexico," having a body length of 626 mm., a
tail length of 168 mm. and a total length of 786 mm. No small
juveniles have been examined; the smallest specimen (AMNH 19618) is a
male from Veracruz, Mexico, having a body length of 325 mm., a tail
length of 90 mm. and a total length of 415 mm.
The greatest variation is in coloration. In preserved specimens the
ground-color is white, tannish-white, or often pale blue, with dark
stripes of black or deep brown present dorsolaterally and laterally.
Secondary stripes of paler brown are sometimes present, but the pale
browns have faded badly on many specimens. Normally four black stripes
are present at mid-body--a lateral pair on the 4th row of dorsal scales
and a dorsolateral pair on the 7th row (fig. 1, D). The lateral pair
is the posterior continuation of the stripe that on the head passes
through the eye; it continues on the nape as a narrow stripe on the
4th row only. In a few specimens the lateral stripe broadens to
include the upper third of the 3rd row posterior to the nape. In some
specimens both the dorsolateral and lateral dark stripes are present
on the nape as a row of elongated spots or dashes that become
continuous stripes of even width one-third to one-half of the distance
posteriorly along the body; in other specimens the stripes are
continuous on the nape. Posterior to the place of dorsal
scale-reduction from 19 to 17 rows by the fusion of the 3rd and 4th
rows, the lateral and dorsolateral stripes are moved downward by one
row. In some specimens secondary black or dark brown stripes are
present in the form of a series of dashes on the 5th and 8th rows;
posterior to the place of scale reduction, these dashes are on the 4th
and 7th rows. These dashes form a continuous stripe near the base of
the tail. On the tail the secondary and primary stripes on adjacent
rows sometimes fuse into a single broader stripe.
Usually the 1st row of dorsal scales is dark brown; in some specimens
the brown on the 1st or 7th row has faded in preservative. A few
specimens have small black spots on the moderate brown background of
the 1st row; in others the 1st row is only a somewhat darker brown
than the ground-color. The 2nd row sometimes is a medium brown, and
appears to be an additional stripe.
The ventrals usually have more or less conspicuous dark spots
laterally; in some specimens there are no spots. Except for the
lateral spots (when present) the ventrals are immaculate white. The
dorsal ground-color is pale brownish-white, white or pale blue between
the 4th and 7th rows of dorsal scales and dorsally between the 7th
rows on each side. Stripes are never present on the uniformly pale
colored 8th, 9th and vertebral scale-rows.
Usually there are eight supralabials on each side; however, seven of
the 27 specimens examined have seven supralabials on each side, and
three others have seven on one side, and eight on the other. Never is
more than the lower third of the supralabials dark brown. In many
specimens little or no brown is on the supralabials. There is little
or no brown on the chin.
Variation in coloration and in number of supralabials appears to be of
no geographic significance.
Although no juveniles have been collected, I expect that juveniles
resemble adults in coloration. Probably there would be a greater
contrast between the dark stripes and the pale ground-color in
juveniles.
In life an adult from three miles northwest of Lerdo de Tejada,
Veracruz, Mexico (UMMZ 114484), had black stripes on the 4th and 7th
rows of dorsal scales, and black spots on a brown background on the
1st row. The 2nd row had a medial, pale to medium brown auxiliary
stripe on a brownish-white background. Posterior to the nape the 3rd
row was medium brown. The area between the 4th and 7th rows and the
dorsum between the 7th row of scales on each side was a pale
brownish-white. Posterior to the place of scale-reduction the primary
stripes were displaced downward by one row to the 3rd and 6th rows and
secondary stripes originated as elongated spots on the 4th and 7th
rows. Near the tail the secondary stripes were broad and continuous.
The head was white or tannish-white with three dark brown or black
stripes.
_Remarks._--In his diagnosis of _C. l. lineatus_, Smith (1941:122)
states: "lateral dark stripe ... very narrow posterior to nape,
extending along fourth scale row; posteriorly a stripe along third and
eighth (farther posteriorly the seventh) scale rows; a narrow dark
stripe along sixth scale row, continuous throughout length of
body...." I fail to find a dark stripe on the 6th row throughout the
length of the body. In all specimens that I have seen, there is a dark
stripe on the 7th row anteriorly and on the 6th row posteriorly. In
many specimens the stripes on the 3rd and 8th (posteriorly the 7th)
scale-rows are absent or present so far posteriorly that the 8th row
is never involved.
The dark brown on the first scale-row and the presence of a lateral
dark stripe on the 4th row of dorsal scales only, in combination with
the characteristics of the genus, distinguish _C. l. lineatus_ from
all other snakes in Mexico.