The Project Gutenberg eBook of Systematic Status of the Colubrid Snake, Leptodeira discolor Günther
most other parts of the world at no cost and with almost no restrictions
whatsoever. You may copy it, give it away or re-use it under the terms
of the Project Gutenberg License included with this ebook or online
at www.gutenberg.org. If you are not located in the United States,
you will have to check the laws of the country where you are located
before using this eBook.
Title: Systematic Status of the Colubrid Snake, Leptodeira discolor Günther
Author: William Edward Duellman
Release date: January 14, 2011 [eBook #34954]
Language: English
Credits: Produced by Chris Curnow, Monika Krämer, Joseph Cooper and
the Online Distributed Proofreading Team at
https://www.pgdp.net
*** START OF THE PROJECT GUTENBERG EBOOK SYSTEMATIC STATUS OF THE COLUBRID SNAKE, LEPTODEIRA DISCOLOR GÜNTHER ***
[Pg 1]
Museum of Natural History
Volume 11, No. 1, pp. 1-9, 4 figs.
July 14, 1958
Leptodeira discolor Günther
Lawrence
1958
[Pg 2]
University of Kansas Publications, Museum of Natural History
Robert W. Wilson
Published July 14, 1958
University of Kansas
Lawrence, Kansas
PRINTED IN
THE STATE PRINTING PLANT
TOPEKA, KANSAS
1958
[Pg 3]
Systematic Status of the Colubrid Snake,
Leptodeira discolor Günther
BY
WILLIAM E. DUELLMAN
At the time of completing my study of the genus Leptodeira
(1958) I had seen no specimens of Leptodeira discolor, a species
described by Günther in 1860 and subsequently referred to the
genus Hypsiglena by Cope (1887), Boulenger (1894), and Mocquard
(1908), and to the genus Pseudoleptodeira by Taylor (1938).
Günther's description was based on two syntypes (British Museum
of Natural History numbers 1946.1.23.67 and 68) collected in
Oaxaca, México, by Auguste Sallé. Information concerning the
scutellation and coloration of the syntypes was provided by J. C.
Battersby; in my revisionary study (op. cit.) this information was
included in a short discussion of the species, which was referred to
incerta sedis until specimens could be examined and the relationships
of the species determined.
Through the courtesy of John M. Legler of the Museum of Natural
History, University of Kansas, I have been able to study a
specimen of Leptodeira discolor obtained six miles southeast of
Tamazulápam, Oaxaca, México, by J. R. Alcorn on June 22, 1955.
Superficial examination of the external characters of this snake
shows a striking resemblance to Leptodeira. The specimen has a
vertical pupil, divided anal, 21 scale rows, and two apical pits. The
enlarged posterior maxillary teeth are without a trace of a groove.
Examination of the hemipenis revealed that the organ was bifurcate
and had a forked sulcus; these penial characteristics are diagnostic
of the subfamily Xenodontinae and not the subfamily Colubrinae
that includes the genera Hypsiglena and Leptodeira.
Examination of all available xenodontine genera indicates that
this snake belongs to a heretofore unnamed genus. In recognition
of the mental torment customarily suffered by workers attempting
to ascertain the relationships of the many genera of colubrid snakes,
I propose the generic name
Tantalophis, new genus
Leptodeira (in part), Günther, Proc. Zool. Soc. London, pp. 317-318, 1860;
Garman, Bull. Essex Inst., vol. 16, p. 23, January 9, 1884; Dunn, Proc. Nat.
Acad. Sci., vol. 22, pp. 697-698, December, 1936; Duellman, Bull. Amer. Mus.
Nat. Hist., vol. 114 (1), pp. 95-96, February 24, 1958.
Hypsiglena (in part), Cope, Bull. U. S. Nat. Mus., no. 32, p. 78, 1887;
Günther, Biologia Centrali-Americana, Reptilia, pp. 137-138, pl. 49, fig. A,[Pg 4]
October, 1894; Boulenger, Catalogue Snakes British Museum, vol. 2, p. 211,
September 23, 1894; Mocquard, in Duméril and Bocourt, Mission Scientifique
Mexique l'Amerique Centrale, vol. 3, p. 871, 1908; Amaral, Mem. Inst. Butantan,
vol. 4, p. 183, May, 1930.
Pseudoleptodeira (in part) Taylor, Univ. Kansas Sci. Bull., vol. 25, no. 15,
p. 343, June 1, 1938.
Type Species.—Leptodeira discolor Günther, Proc. Zool. Soc. London, pp.
317-318, 1860.
Diagnosis.—A xenodontine colubrid snake having a bifurcate hemipenis with
a forked sulcus spermaticus, many longitudinal folds on basal portion, and small
spines and calyces on distal part; 12 or 13 maxillary teeth followed by short
diastema and two somewhat enlarged maxillary teeth lacking grooves; small
parotid gland; normal colubrid skull; no hypapophyses on posterior vertebrae;
elliptical pupils; two apical pits; smooth scales; normal colubrid head shields;
divided anal; paired caudals.
The generic name comes from the Greek Τανταλοσ, a mythological character
symbolic of eternal torment, and from the Greek οφισ for snake.
Tantalophis discolor (Günther) New comb.
The synonymy for the species is indicated in the account of the genus. The
description below of the species is based on an adult male from 6 miles southeast
of Tamazulápam, Oaxaca, México (University of Kansas Museum of Natural
History No. 40143).
Scutellation.—Head shields normal; upper labials 7-7 (third and fourth
entering orbit); lower labials 9-9 (1-4 in contact with anterior chin-shield,
4 and 5 in contact with posterior chin-shield); preoculars 1-1 and not in contact
with frontal; postoculars 2-2; temporals 1-2-3, 1-2-3; nasals divided by a
distinct groove below nostril and faint groove above; portion of rostral visible
from above, one-third length of internasals; internasals pentagonal and one-half
as long as prefrontals; parietal suture approximately as long as frontal; ventrals
178; anal divided; caudals 80. Scales in 21 rows at midbody and showing the
following reduction:
2 + 3 (130) 8 + 9 (162)
21 ————— 19 ————— 17 (178)
2 + 3 (130) 8 + 9 (152)
Coloration.—Dorsal ground-color light brown and extending onto edges of
ventrals; transverse body blotches numbering 50, each 1½ to 3 scales long and
separated by light interspaces 1½ to 2 scales long; blotches brownish black and
extending onto second scale row; lateral intercalary spots forming dark smudges
on rows 1 and 2. Top of head black, flecked with tan; nape cream, followed
by dark band six scales long; dark nape stripe from posterior edges of parietals
to first dark body band. Venter cream-tan; throat and labials cream; posterior
margins of all upper labials and of lower labials 1-3 black-edged (Figure 1).
Size and Proportions.—Head and body 312 mm. long; tail 118 mm., amounting
to 37.8 per cent of length of head and body.
[Pg 5]
Fig. 1. Dorsal and lateral views of the head of Tantalophis discolor (Günther).
(KU No. 40143). × 7.
Variation.—Data on the syntypes of Leptodeira discolor furnished by J. C.
Battersby give some indication of the variation in the species. Both are males,
and they have 175 and 180 ventrals, 88 and 89 caudals, 1 preocular, 2 postoculars,
1-2-3 temporals, 7 and 8 upper labials, 9 lower labials. They have[Pg 6]
body lengths of 365 and 402 mm., total lengths of 509 and 555 mm., tail/body
ratios of 38.0 and 39.4. They have 51 and 54 dark blotches on the body.
Skull.—The skull is typically colubrid and shows no modifications. The
quadrate has both a median and a lateral depression, forming a strong lateral
flange on the anterior edge; the columellar process is elliptical, and the supracolumellar
crest is robust. The posteroinferior vomerine process extends directly
posteriorly and then angles sharply posterodorsally, enclosing an elliptical
vomerine fenestra. The lateral processes of the premaxillary are slightly
pointed; the median spine is relatively thin and high. The pterygoids bear
23 and 21 teeth that decrease in size posteriorly; the transpalatine articulating
process of the pterygoid is rounded, not robust; the lateral crest is high and
moderately robust; the depression in the ventral surface of the pterygoid is
moderate. There are 12 and 13 maxillary teeth that increase in size posteriorly;
these are followed by a short diastema and two larger, solid teeth. The
prediastemal teeth are slightly curved and slender. The maxillary is laterally
compressed; the posterior knob is not robust; there is one foramen in the
lateral face of the bone (Figure 2). The 10 palatine teeth are almost uniform
in size; the dentary bears 19 teeth that decrease in size posteriorly.
Fig. 2. Lateral view of the left maxillary of Tantalophis discolor (Günther).
(KU No. 40143). × 17.
A thin and otherwise small parotid gland or "venom sac" extends posteriorly
from beneath the eye to about the angle of the jaw; a minute duct
connects with the anteromedian surface and extends to the fleshy part of the
mouth at the posterior end of the maxillary (Figure 3).
Fig. 3. Lateral view of the head of Tantalophis
discolor (Günther), showing the position and relative size of the parotid
gland. (KU No. 40143). × 17.
Hemipenis.—In situ the hemipenis extends to the posterior edge of the
thirteenth caudal. The unforked part of the organ is bedecked with numerous
heavy longitudinal folds alternating with thinner folds. The basal parts of
the two heads are covered with moderate sized spines, those closest to the base
and the sulcus being the smallest. The distal parts of the heads are covered[Pg 7]
with calyces. The sulcus bifurcates on the unforked part of the organ at a
point about two-thirds of the distance from the base to the division of the
organ. The sulcus is a deep groove between heavy folds proximally and is a
shallower furrow distally (Figure 4).
Fig. 4. Hemipenis of Tantalophis discolor
(Günther). The organ was cut on the ventral surface and opened.
(KU No. 40143). × 4.
Relationships.—Using Dunn's (1928) arrangement of the American
colubrid snakes as a guide permits the taxonomist to group
Tantalophis with several genera, some of which occur in South
America and others in the West Indies. Although the significance
of such generic characters as scale pits and nature of the hemipenis
is not clear, these characters must, of necessity, be utilized in attempting
to ascertain the relationships of Tantalophis to other
colubrid snakes. Assuming that the primary divisions of the
American colubrids into subfamilies based on the nature of the
sulcus spermaticus and the presence or absence of hypapophyses on
the posterior vertebrae have some reality, Tantalophis must be
placed in the subfamily Xenodontinae comprising genera chiefly
South American in their distribution, but with several genera in
Middle America and a few in North America and the West Indies.[Pg 8]
In order to limit the number of genera to be compared with Tantalophis,
only those xenodontines having apical pits and bifurcate
hemipenis are considered. These include Cyclagras, Drepanoides,
Hypsirhynchus, Ialtris, Leimadophis, Pseudablabes, Siphlophis,
Tachymenis, Tomodon, and Trypanurgos. Aside from differences in
scutellation, Leimadophis, Siphlophis, and Trypanurgos have the
heads of the hemipenes terminating in a disc, and Ialtris has a plicate
hemipenis. Tomodon has basal spines on the hemipenis. The
hemipenes of the other genera have proximal folds, distal spines, and
distal calyces, not greatly unlike the condition found in Tantalophis.
Of these, Cyclagras, Hypsirhynchus, and Pseudablabes have round
pupils and certain differences in scutellation. Drepanoides and
Tachymenis have elliptical pupils like those of Tantalophis, but
Tachymenis has only one apical pit, and Drepanoides has one apical
pit or none. In the above characters no especially close relationship
between Tantalophis and any one of these genera is apparent.
If the characteristics usually employed in distinguishing and relating
genera are ignored and other more subjective criteria are
used, the relationships of Tantalophis still remain obscure. Of the
xenodontine genera Tantalophis approaches Leimadophis in general
physiognomy; perhaps it represents an early divergent stock of
Leimadophis that has undergone radical changes in the hemipenis
and other characters. On the other hand, if the nature of the hemipenis
is of no importance in defining supergeneric groups of colubrid
snakes, Tantalophis may have its relationships with Leptodeira
and Hypsiglena. Although herpetologists have been working intensively
on American colubrids for many decades, the relationships
of the majority of the groups are not well understood. Until
the hemipenes and skulls of all of the forms have been studied and
compared, and the evolutionary significance has been determined
for the characters of the hemipenes, dentition, and apical pits, our
knowledge of the relationships of these snakes will be incomplete.
Remarks.—The individual on which this paper is based is the
only specimen of the species with definite locality data. It is from
a locality six miles southeast of Tamazulápam in northwestern
Oaxaca. This town lies at an elevation of about 6500 feet in the
upper reaches of the Balsas Basin, an arid interior valley that expands
in its upper end to form a broad basin of rolling and dissected
terrain ranging from about 4000 to 6800 feet in elevation. The
countryside around Tamazulápam is arid and supports plants of the
genera Prosopis, Acacia, Ipomoea, and Cassia, and also columnar
cacti. Oaks and pines grow on the limestone hills rising above the[Pg 9]
rolling valley. Tantalophis may be endemic to the Balsas Basin, as
are many other species of reptiles. However, if the snake has its
relatives to the south in lower Central America and South America,
such a distribution seems unlikely, even for an apparent relict.
Acknowledgments.—For permission to study and report on this
specimen I am indebted to Dr. E. Raymond Hall and Mr. John M.
Legler. I am grateful to Dr. Laurence C. Stuart for many helpful
suggestions and to Dr. Norman E. Hartweg for placing at my disposal
the facilities of the Museum of Zoology at the University of
Michigan.
LITERATURE CITED
Amaral, A. do
1930 Estudos sobre ophidios neotropicos XVIII—Lista remissiva dos
ophidios da região neotropica. Mem. Inst. Butantan, 4:129-275.
Boulenger, G. A.
1894 Catalogue of the snakes in the British Museum (Natural History).
London, 2:xi + 382, pls. 1-20, figs. 1-25.
Cope, E. D.
1887 Catalogue of the batrachians and reptiles of Central America and
Mexico. Bull. U. S. Nat. Mus., 32:1-98.
Duellman, W. E.
1958 A monographic study of the colubrid snake genus Leptodeira.
Bull. Amer. Mus. Nat. Hist., 114:1-152, pls. 1-31, figs. 1-25, maps
1-25.
Duméril, A. M., and Bocourt, F.
1870-1909 Études sur les reptiles. Mission scientifique au Mexique et
dans l'Amerique Centrale, Recherches zoologiques. Paris, Pt. 3,
1:xiv + 1012, pls. 1-77.
Dunn, E. R.
1928 A tentative key and arrangement of the American genera of Colubridae.
Bull. Antivenin Inst. Amer., 2 (1):18-24.
1936 Notes on North American Leptodeira. Proc. Nat. Acad. Sci., 22
(12):689-698.
Garman, S.
1884 The North American reptiles and batrachians. Bull. Essex Inst.,
16:1-46, 3 figs.
Günther, A. C. L. G.
1860 On new reptiles and fishes from Mexico. Proc. Zool. Soc. London,
pp. 316-319.
1885-1902 Biologia Centrali-Americana. Reptilia and Batrachia. London,
pp. xx + 1-326, pls. 1-76.
Taylor, E. H.
1938 Notes on Mexican snakes of the genus Leptodeira, with a proposal
of a new snake genus, Pseudoleptodeira. Univ. Kansas Sci. Bull.,
25:315-355, pls. 30-34, figs. 1-7.
Transmitted March 11, 1958. Contribution No. 11 from the Department of
Biology, Wayne State University, Detroit 2, Michigan.
Featured Books
If: A Play in Four Acts
a dog, and then they thinks they can talk at yer and talk at yer, and say wot they likes, like...
Read More
The Legends of King Arthur and His Knights
by hispermission, I Dedicated it before I was personally known to him.JAMES KNOWLES.Addendum by Lad...
Read More
Cottontail Rabbits in Relation to Trees and Farm Crops
ons are the severalnative species of rabbits. These animals do considerable damage togarden truck an...
Read More
Geographic Variation in the Pocket Gopher, Thomomys bottae, in Colorado
arily in the Piñon-juniper,Ponderosa Pine, and Short Grass zones of Daubenmire (1943) but in somelo...
Read More
Subspeciation in the Meadow Mouse, Microtus montanus, in Wyoming and Colorado
hytic grasses used by the mouse for food, for protection fromenemies, and for shelter from the eleme...
Read More
The Story of Red Feather: A Tale of the American Frontier
OTHER AND SISTER—THE SIGNALIT is within my memory that Melville Clarendon, a lad of sixteen years,...
Read More
Famous Modern Ghost Stories
lackwoodThe Shadows on the WallBy Mary E. Wilkins FreemanThe MessengerBy Robert W. ChambersLazarusBy...
Read More
The outlaw of Torn
shookEngland from north to south and from east to west; and reached across thechannel and shook Fran...
Read More
Comments on "Systematic Status of the Colubrid Snake, Leptodeira discolor Günther" :