Buena Vista; Copuyo (6); Charapendo (3); Cofradía; Jaramillo; Jungapeo; San Salvador; Tuxpan.
Specimens of Hypopachus from the Balsas drainage in Michoacán have characters consistent with topotypic H. caprimimus. Eleven specimens from the southern edge of the Mexican Plateau all have the flanks darker than the dorsum, a distinct and continuous dark stripe from the occiput to the groin, a large dark spot in the inguinal region, and a pair of dark transverse stripes on the thigh and shank (Pl. 6, Fig. 1). With the exception of three specimens from Charapendo, all have a predominantly brown venter with round, cream-colored spots.
Peters (1954:8) referred specimens from Buena Vista and San Salvador to Hypopachus oxyrrhinus. He stated that the specimen (BMNH 1914.1.28.150) from San Salvador had flanks much darker than the dorsum and a well-defined continuous stripe from the occiput to the groin; this specimen has the characters of H. caprimimus. The specimen (BMNH 1914.1.28.151) from Buena Vista resembles H. oxyrrhinus in some characters, but it is not like H. oxyrrhinus ovis on the Mexican Plateau in Michoacán. The specimen has paired transverse stripes on the hind limbs as does H. caprimimus, and is here referred to that species.
In Michoacán this species has been collected in arid tropical scrub forest at elevations of 200 to 1800 meters in the northern foothills of the Sierra de Coalcomán, the Tepalcatepec and Tuxpan valleys, and on the lower slopes of the Cordillera Volcánica. Calling males have been found along streams. One specimen from Charapendo was regurgitated by a Leptodeira maculata.
Hypopachus oxyrrhinus ovis Taylor
Hypopachus ovis Taylor, Univ. Kansas Sci. Bull., 26:520, November 27, 1940.—Tepic, Nayarit, México.
Hypopachus oxyrrhinus ovis, Shannon and Humphrey, Herpetologica, 14:89, July 23, 1958.
Emiliano Zapata; 30 km. NW of Jacona (2); 10 km. NE of Pátzcuaro (2); Tangamandapio (16); 24 km. W of Zamora (16).
Thirty-seven specimens from the Mexican Plateau in northwestern Michoacán agree well with the diagnosis of Hypopachus oxyrrhinus ovis by Shannon and Humphrey (1958). With the exception of one specimen from Tangamandapio, all have dark bellies extensively mottled or spotted with cream-color. Most of the specimens have some form of an irregular, usually broken, dark line from the occiput to the groin. In eight specimens there is no line or linear arrangement of spots; instead the dorsum is spotted or flecked with dark brown. The ground color of the dorsum and flanks varies from dull reddish brown to grayish brown; cream-colored spots are evident on the flanks and posterior surfaces of the thighs in all specimens (Pl. 6, Fig. 2).
In comparison with 14 specimens from Quesería, Colima (UMMZ 80001-2), individuals from the Mexican Plateau have a darker venter with bolder markings, and a more mottled dorsum.