Conopsis acuta ( Cope, 1886 ) Cope, 1886

Goyenechea, Irene & Flores-Villela, Oscar, 2006, Taxonomic summary of Conopsis, Günther, 1858 (Serpentes: Colubridae), Zootaxa 1271, pp. 1-27 : 6-7

Conopsis acuta ( Cope, 1886) n. comb.

Ogmius varians Cope (non Jan), 1869:162. O (gmius) acutus Cope, 1886 in Ferrari­Perez:189. Ogmius acutus Cope, 1887:82 .

Toluca lineata acuta ( Cope), 1886:346 .

Chionactis diasii acutus Cope, 1898 (1900) :943. Toluca lineata wetmorei Smith, 1943:489 . nov. sin.

Type specimen: USNM 30552.

Type locality: Juchitán, Oaxaca. This locality is obviously in error since is out of the known geographic and elevation ranges of the species.

We propose to restrict the type locality for Conopsis acuta to: 2 millas E Ixtlán de Juárez ( AMNH 91054), since apparently Cope, 1886 made a mistake citing the locality for the specimen he described as from "....Tuchitan, on the Pacific side of the isthmus of Tehuatepec.". Latter Smith and Taylor (1950:p.338) pointed that the type locality for this taxon is Juchitán, Oaxaca. The type specimen was sent to the US National Museum by Sumichrast ( Cope, 1886 in Ferrari­Perez:189). Our restriction is based on the statement of Sumichrast (1873) refering the species as inhabiting the temperate highlands of Mexico. This locality may have been within the sphere of Sumichrast activity and was probably readily accessible to him.

Diagnosis: This snake is characterized by the following combination of characters: divided internasals and prefrontals; brown dorsal coloration, or some individuals with a grayish dorsum and a vertebral line of elongated hexagonal spots; with tessellated sides, or two paravertebral dark lines. Ventrally it is yellowish or yellow­orange, with no spots or with a row of paired dots on each end of the ventral scales. It differs from C. nasus and C. megalodon by having divided prefrontals and internasals, scales fused in the latter two species. The dorsal spot pattern may be similar in the three. Conopsis acuta is a smaller snake (SVL 100–225 mm) compared to the other two species, C. nasus (SVL: 100–320 mm) and C. megalodon (SVL: 107–250 mm); C. acuta differs from C. lineata by lacking continuous lines along the dorsum and its smaller size ( C. lineata SVL: 100–273 mm).

Description: A species with divided prefrontals and internasals; loreal scale on each side of head; a pointed rostral; nasal pierced by nostril on each side of head; a preocular and two postoculars; hexagonal frontal, contacting prefrontals; temporal formula 1+2; 7 upper and lower labials; 2.5 upper labials before eye; genial shields separated by one scale; a mean of 123 ventrals (106–135) and 31 subcaudals (28–42); 17 rows of smooth scales at midbody; dorsum brown,with vertebral line of elongated hexagonal spots; sides of body tessellated; venter yellowish, with no marks.

Measurements: Adult specimens of Conopsis acuta average 185.4 mm snout­vent length (120–225 mm), 222.0 mm in total length (153–270 mm), body diameter 7.2 mm. Variation: This species generally shows a loreal scale on each side of head (68.8% of examined specimens), or loreal may be missing in some (31.2%). Upper labials usually 7–7 (86.2%), but some have 6–6 (10.4%); or 7–6 (3.4%). Upper labials before eye from 2.5 (69%) to 3 (31%). Lower labials from 7 (65.6%) to 6 (31.1%), one specimen had 5–7. First pair of genial shields separated by one (75.9%) or two scales (13.8%), or may be fused (10.3%). Dorsal coloration is brown (69%), gray (13.9%), cinnamon (10.3%), or beige (6.8%); with a vertebral row of hexagonal spots (79.3%), or a vertebral row of hexagonal spots and two paravertebral rows of spots, or a vertebral row of large hexagonal spots and three dorsal lines along body, but vertebral line more prominent and forming small hexagons (20.7%). Ventral coloration creamy (69%), yellow (27.6%), or yellowish­gray color (3.4%). The venter has a row of large or small­paired dots (37.9%), dots at the edge of the ventral scales (17.2%), intercalated dots through the whole belly (6.8%), or is immaculate (34.6%).

Distribution: Conopsis acuta is distributed in the highlands of south­central Mexico (fig. 2); it has been collected in the states of Oaxaca, Puebla, and Veracruz, from 1800 to 2600 m, in xerophilous underbrush, Opuntia (prickly pear), pine, pine­oak, and fir forests. It is usually under rocks or litter during most of the year, being more abundant in the months of August, September, and November.