Ophryacus undulatus (JAN, 1859)
|Higher Taxa||Viperidae, Crotalinae, Serpentes (snakes)|
|Common Names||Mexican Horned Pit Viper|
|Synonym||Trigonocephalus (Atropos) undulatus JAN 1859|
Lachesis undulatus BOULENGER 1896
Bothrops sphenophrys SMITH 1960
Ophryacus undulatus — CAMPBELL & LAMAR 1989: 311
Ophryacus undulatus — LINER 1994
Ophryacus undulatus — WELCH 1994: 95
Ophryacus undulatus — MCDIARMID, CAMPBELL & TOURÉ 1999: 314
Ophryacus undulatus — JADIN et al. 2011
|Distribution||Mexico (Guerrero, Oaxaca: Sierra Madre Oriental, Mesa del Sur, Sierra Madre del Sur, Puebla)|
sphenophrys: Oaxaca; Type locality: Mexico: El Soledad, Oaxaca.
Type locality: "Messico" [Mexico]. Proposed restriction to "Orizaba, Veracruz, Mexico" by Smith and Taylor, 1950: 350. Map legend:
- Region according to the TDWG standard, not a precise distribution map.
NOTE: TDWG regions are generated automatically from the text in the distribution field and not in every cases it works well. We are working on it.
|Types||Syntypes: MSNM (2), Milan Museum|
Holotype: UIMNH 6262, W.L. Burger; July 22, 1949 [sphenophrys]
Type species: Trigonocephalus undulatus JAN 1859 is the type species of the genus Ophryacus COPE 1887.
Definition and diagnosis: Rostral broader than high, moderately to distinctly concave; three preoculars, upper largest and undivided, middle not fused with supralacunal, lower small, somewhat excluded from margin of orbit; three to four supraoculars along dorsal margin of eye including supraocular spine; ten to 13 supralabials; lip margin not scalloped; nine to 14 infralabials; single scale above eye forming long, relatively slender spine, slightly compressed to sub- circular in cross section, not occupying most of dorsal margin of orbit, tip pointed; adjacent scales along dorsal ocular margin often also modified, projecting slightly; canthals and internasals often raised into short spines or with especially high keels; scales in the supraocular region small and keeled; ten to 20 (usually 12–18) intersupraoculars; top of head covered with small scales, most having tubercular keels; second supralabial usually separated from prelacunal by single small subfoveal; subocular and supralabial series separated by two to four rows of small, roundish scales; 21 mid-dorsal scale rows; mid- dorsals at midbody not noticeably broad, obtusely rounded; keel generally extending to tip of scale or nearly so, apical pits not apparent; free portion of apex of dorsal scales moderate in extent, barely over- lapping contiguous scale; interstitial epidermal fold at cranial end of scale well developed; 157–178 ventrals; 37–57 subcaudals, divided; tail spine straight, about as long as preceding two to three subcaudals, pointed or obtusely rounded.
Frontal bones with concave dorsal surface, strongly elevated margins, moderately longer than wide; post- frontals moderate in size, not contacting frontal, comprising about equal amount of dorsal perimeter of orbit as parietals; posterolateral edges of dorsal surface of parietals forming distinct flat shelf continu- ing onto parietal as a raised ridge; junction between parietal and pro-otic irregular, not particularly angular; anterior portion of ectopterygoid possessing a shallow depression on medial side accommodating attachment of ectopterygoid retractor muscle; ectop- terygoid noticeably longer than expanded, flattened base of pterygoid (posterior to articulation with ectop- terygoid) with flat shaft tapering posteriorly; apex of choanal process positioned at about midlength on palatine, process moderately reduced in height, apex broadly rounded; dorsal surface of parietal roughly triangular; zero to one (usually zero) palatine teeth, seven to ten pterygoid teeth, seven to nine dentary teeth; pterygoid teeth extending to level of articula- tion of pterygoid with ectopterygoid; maxillary fang relatively short, only slightly longer than height of maxilla; fang at rest extending to level of suture between supralabials 7 and 8; splenial and angular bones fused; haemapophyses in contact distally.
Dorsum with zig-zag pattern; ground colour olive- brown, green, or grey, sometimes orange or yellow pigment present; dorsal scales usually finely mottled or speckled with black [from JADIN et al. 2011].
|Etymology||Etymology (genus): The generic name is derived from the Greek ophrys, meaning brow, and the Latin acus, meaning pointed, obviously in reference to the dis- tinctive supraocular spine-like scale.|