The Amphibians and Reptiles of Michoacan, Mexico Part 20

~Hypsiglena torquata ochrorhyncha~ Cope

_Hypsiglena ochrorhyncha_ Cope, Proc. Acad. Nat. Sci.

Philadelphia, 12:246, November 15, 1860.--Cape San Lucas, Baja California, Mexico.

_Hypsiglena torquata ochrorhyncha_, Bogert and Oliver, Bull.

Amer. Mus. Nat. Hist., 83:378, March 30, 1945.

Tupataro.

The systematic status of the geographic variants of _Hypsiglena_ in Mexico and southwestern United States has been commented on by several authors. Tanner (1944) considered _H. torquata_ and _H. ochrorhyncha_ to be distinct species; Bogert and Oliver (1945:379) and Duellman (1957b:238) presented evidence indicating that _H. torquata_ and _H.

ochrorhyncha_ intergrade in Sinaloa and southern Sonora. In _Hypsiglena_ the scutellation, including the numbers of l.a.b.i.als, dorsals, ventrals, and caudals, seem to vary in a clinal manner. Nevertheless, these snakes can be divided into two distinct populations on the basis of the nuchal color pattern, consisting of an _ochrorhyncha_-type (a broad dark nape-band, the lateral edges of which extend anteriorly and fuse with a pos...o...b..tal stripe, and a narrow nape stripe extending from the posteromedian edges of the parietals to the dark nape band) and a _torquata_-type (a somewhat narrower dark nape-band bordered anteriorly by a pale nuchal area, and no dark nape stripe). Snakes having the _ochrorhyncha_-type of nuchal pattern are found on the Mexican Plateau from Michoacan northward into the desert regions of Sonora and the southwestern United States. Snakes having the _torquata_-type of pattern are found on the coastal lowlands and adjacent slopes of the Sierra Madre Occidental from southern Sinaloa to Colima and thence inland in the Balsas-Tepalcatepec Basin to Morelos and Guerrero. An exception is _Hypsiglena torquata dunklei_ from Forlon and San Fernando, Tamaulipas; it has the _torquata_-type of nuchal pattern. The distributional picture is somewhat complicated because some individuals having the _torquata_-type of nuchal pattern also have a faint nape stripe. If these are taken as exceptions, the general picture of distribution in Mexico is _H. t. torquata_ on the Pacific lowlands from Sinaloa southward to the Balsas Basin and _H. t. ochrorhyncha_ on the Mexican Plateau.

Smith (1943:433) resurrected _Hypsiglena jani_ Duges for the snakes of the _ochrorhyncha_-type on the southern part of the Mexican Plateau. He stated that the southern specimens differed from northern ones in having a nuchal spot 9 or 10 scales in length, as compared with a spot 2 to 6 scales in length in northern specimens. A cursory examination of specimens from the areas between Arizona and Michoacan showed that there is a gradual increase in the size of the spot from north to south. If no other characters can be found to distinguish the populations, they should be considered as a single subspecies.

_Hypsiglena affinis_ differs from _H. torquata_ in possessing 19 instead of 21 rows of dorsal scales. Additional material is needed from the western slopes of Jalisco and the Barrancas in Zacatecas and Durango, before definite allocation of _affinis_ can be made.

Bogert and Oliver (1945:379) discussed the status of certain named populations in Baja California and concluded that only one species occurs there, and that the species probably is conspecific with _H.

torquata_. A careful review of the genus _Hypsiglena_ might show that there is only one species.

The one specimen from Michoacan (USNM 46513) is from an elevation of about 2300 meters near the southern edge of the Mexican Plateau.

~Hypsiglena torquata torquata~ (Gunther)

_Leptodeira torquata_ Gunther, Ann. Mag. Nat. Hist., ser. 3, 5:170.--Laguna Island, Nicaragua (in error).

_Hypsiglena torquata torquata_, Taylor, Univ. Kansas Sci.

Bull., 25:371, July 10, 1939.

Apatzingan; Capirio; Cofradia.

Specimens from the three mentioned localities have the dark nuchal spot bordered anteriorly by a pale blotch. In life the specimen from Capirio (UMMZ 114424) had rich reddish brown dorsal spots; the dorsal ground color was grayish white above and somewhat more gray laterally. The pale nuchal area was a cream-color, and the iris was grayish red.

All of the specimens were found in the arid scrub forest in the Tepalcatepec Valley at elevations between 200 and 350 meters.

~Imantodes gemmistratus gracillimus~ (Gunther)

_Dipsas gracillima_ Gunther, Biol. Centrali-Americana, Rept., p. 177, July, 1895.--southern Mexico. Type locality restricted to Acapulco, Guerrero, Mexico, by Smith and Taylor (1950a:331).

_Imantodes gemmistratus gracillimus_, Zweifel, Amer. Mus.

Novitates, 1961:12, September 16, 1959.

La Orilla.

The specimen from La Orilla was reported by Peters (1954:23) as _Imantodes gemmistratus oliveri_; Zweifel (1959c) showed that _I. g.

oliveri_ did not range west of Tehuantepec and that the snakes inhabiting the coastal lowlands of Guerrero, Michoacan, and Colima were a.s.signable to the subspecies _gracillimus_. It may be a.s.sumed that this subspecies ranges throughout the coastal lowlands and foothills of the Sierra de Coalcoman.

~Imantodes gemmistratus latistratus~ (Cope)

_Dipsas gemmistrata latistrata_ Cope, Bull. U. S. Natl.

Mus., 32:68, 1887.--Southern Jalisco. Type locality restricted to Guadalajara, Jalisco, Mexico, by Smith and Taylor (1950a:334).

_Imantodes gemmistratus latistratus_, Zweifel, Amer. Mus.

Novitates, 1961:3, September 16, 1959.

El Sabino.

The one specimen from Michoacan was collected near the upper limits of the scrub forest on the slopes of the Cordillera Volcanica. Zweifel (1959c:10) stated that in certain aspects of coloration this specimen was like _I. gemmistratus gracillimus_, but in scutellation and other features of coloration it was like _I. g. latistratus_. There are too few specimens of this species to define the ranges of the various subspecies with any degree of accuracy, but from the limited number of specimens available, it seems that _I. gemmistratus gracillimus_ occurs on the Pacific lowlands from Guerrero northward to Colima. Northward on the Pacific lowlands from Colima to Sinaloa and in the Balsas-Tepalcatepec Basin is found _I. gemmistratus latistratus_.

~Lampropeltis doliata~ (Linnaeus)

_Coluber doliatus_ Linnaeus, Systema naturae, ed. 12, 1:379, 1766.--Charleston, South Carolina.

_Lampropeltis doliata_, Klauber, Copeia, No. 1:11, April 15, 1948.

Coalcoman (3); El Sabino; 24 km. W of Morelia; Rio Nexpa; Uruapan.

The few specimens of this species from Michoacan show a wide range of variation; furthermore, the present systematic status of the subspecies of _Lampropeltis doliata_ portrays an incongruous pattern of distribution. Specimens from the Sierra de Coalcoman have relatively narrow red bands that are not interrupted dorsally by extensions of the black rings; the scales in the red bands have black tips. The specimen from El Sabino (EHT-HMS 5253) and the one from the Rio Nexpa on the coast (USNM 31491) have broader red bands; the scales in the red bands do not have black tips. A specimen from 24 kilometers west of Morelia (UIMNH 17782) and one from Uruapan (UMMZ 121508) have the red bands interrupted dorsally by extensions from the black rings.

Specimens from the Sierra de Coalcoman were referred to _L. doliata blanchardi_ by Peters (1954:24), who noted that in some characters these snakes were like _L. d. nelsoni_ and in others like _L. d.

polyzona_. The individual from El Sabino was referred to _L. d. nelsoni_ by Taylor (1940c:465); the one from 24 kilometers west of Morelia was referred to _L. d. arcifera_ by Smith (1942c:198). If these a.s.signments are correct, three subspecies of _Lampropeltis doliata_ occur in Michoacan: _blanchardi_ in the Sierra de Coalcoman, _nelsoni_ on the coast and in the Tepalcatepec Valley, and _arcifera_ on the Mexican Plateau and in the Cordillera Volcanica. Such a distribution is plausible, but the few specimens and our general lack of knowledge of the variation and relations.h.i.+ps of the different populations do not permit a definite a.s.signment at this time.

~Lampropeltis ruthveni~ Blanchard

_Lampropeltis ruthveni_ Blanchard, Occ. Pap. Mus. Zool.

Univ. Michigan, 81:8, April 28, 1920.--Patzcuaro, Michoacan, Mexico.

Morelia; Patzcuaro; Tacicuaro.

At the present time this species is known definitely from only three localities on the Mexican Plateau in Michoacan. An incomplete skin from El Sabino (EHT-HMS 5438) was referred to this species by Taylor (1940c:465); the specimen cannot be found, so verification of the identification cannot be made at this time.

~Leptodeira latifasciata~ (Gunther)

_Hypsiglena latifasciata_ Gunther, Biologia Centrali-Americana, Reptilia, p. 138, October, 1894.--Southern Mexico. Type locality restricted to Huajintlan, Morelos, Mexico, by Smith and Taylor (1950a:331).

_Leptodeira latifasciata_, Dunn, Proc. Natl. Acad. Sci., 22:696, December, 1936.

Apatzingan; El Sabino; La Playa; 32 km. E of Nueva Italia.

This nocturnal snake apparently ranges throughout the arid Balsas-Tepalcatepec Valley to elevations of about 1050 meters. It has been collected only in the arid scrub forest. Aside from the specimens listed by Duellman (1958a:93), there is one (UMMZ 120223) having eight body blotches, a body length of 510 mm. and a tail length of 103 mm.