Systematic Status of the Colubrid Snake,
Leptodeira discolor Günther
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 1918.104.22.168 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, 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