Conopsis biserialis Taylor and Smith, 1942

Goyenechea, Irene & Flores-Villela, Oscar, 2006, Taxonomic summary of Conopsis, Günther, 1858 (Serpentes: Colubridae), Zootaxa 1271, pp. 1-27 : 9

Conopsis biserialis Taylor and Smith, 1942

Conopsis biserialis Taylor and Smith, 1942:333 .

Type specimen: FMNH 100062.

Type locality: 10 miles W Villa Victoria, Estado de México.

Diagnosis: This species is characterized by the following combination of characters: divided internasals and prefrontals; brown­gray dorsal coloration, and two series of dots along body, or a tessellated pattern of dorsal spots. Ventrally it is yellowish with a series of black dots medially. Conopsis biserialis can be distinguished from other species in the genus by its characteristic dorsal spots pattern. Conopsis biserialis shares its characteristic dorsal pattern of spots with Conopsis amphisticha , with which it can be confused, but their geographic ranges do not overlap.

Description: A species with divided prefrontals and internasals; loreal scale on each side of head; a pointed rostral; nasal pierced by the nostril on each side of head; a preocular and two postoculars; hexagonal frontal, contacting prefrontals; temporal formula 1+2; 7 upper labials and 6 lower labials; 2.5 upper labials before eye; genial shields separated by one scale; a mean of 125.4 ventrals (112–146); and 34 subcaudals (26–43); 17 rows of smooth scales at midbody; dorsum brown­gray with two series of dots along body, or a tessellated pattern of spots; venter yellowish with a row of medial dots.

Measurements: Adult specimens of Conopsis biserialis average 200.3 mm in SVL (110–330 mm); 239.92 mm in total length (118–377 mm), body diameter 7.6 mm.

Variation: This species generally shows divided prefrontal and internasals (97%, of examined specimens), or fused (3%). Loreal may be present on both sides of head (60%), absent (22.4%), or it may be present only on one side of head (11.6%). Upper labials 7 (90.6%), 6 (2.9%), or 7/6 (6.5%). Upper labials before eye from 2.5 (82.2%) to 3 (17.8%). Lowerlabials 6 (69.1%), 7 (13.1%), 7/6 (1%), 6/5 (4.7%), or 5 (2.8%). First pair of genial shields separated by one or two scales (72%), or in contact (28%). Dorsal coloration is brown (60%), cinnamon (19%), beige (6.7%), dark brown (5.7%), or gray (.5%); with two vertebral rows of spots (37.5%), a tessellated pattern (34.6%), two rows of spots on anterior third of body, turning into a tessellated pattern afterwards (25.2%), or no pattern (9.3%). Ventral coloration creamy (80.4%) to yellow (19.6%). The venter has a paired row of dots (52.6%), a central row (39%), large dots that form a band on ventral scales (2.8%), or immaculate (8.4%).

Distribution: Conopsis biserialis is distributed in central and southern Mexico (fig. 4), in the states of: Distrito Federal, Guanajuato, Hidalgo, Jalisco, Estado de México, Michoacán, Morelos, and Puebla; from 1700 to 3080 m; in pine forest, oak forest, and montane cloud forest. It is usually under rocks and logs during January, from June to September and December.