Crotalus ornatus HALLOWELL, 1854
Can you confirm these amateur observations of Crotalus ornatus?
|Higher Taxa||Viperidae, Crotalinae, Colubroidea, Alethinophidia, Serpentes, Squamata (snakes)|
|Common Names||E: Black-tailed Rattlesnake|
|Synonym||Crotalus ornatus HALLOWELL 1854: 192|
Crotalus ornatus — ANDERSON & GREENBAUM 2012
Crotalus ornatus — WALLACH et al. 2014: 193
|Distribution||USA (Texas), Mexico (Chihuahua, Nuevo León)|
Type locality: near Pecos River, N. W. Texas.
|Types||Holotype: USNM 486, adult female; Fig. 10) collected by A. Heermann. The specimen was collected during the survey of a railroad route to the Pacific, led by Lieutenant Parke, US Topographical Engineer (collection date unknown).|
|Diagnosis||Diagnosis. Crotalus ornatus (Fig. 11) can be distinguished from most congeners by having (1) a medium-sized SVL (adults 70– 100 cm, rarely to 130 cm SVL); (2) two large, triangular internasal scales; (3) two large prefrontals; (4) two large frontal scales; (5) 6– 10 prefoveals; (6) 2–4 loreals; (7) two preocu- lars; (8) five postoculars; (9) 2–7 intersuprao- culars; (10) 16–18 supralabials; (11) 14–21 infralabials; (12) 23–29 dorsal scale rows at midbody; (13) 164–205 ventrals; (14) 16–30 subcaudals (16–26 in females and 21–30 in males); (15) internasal–prefrontal region and supraoculars black or dark brown; (16) dark pigmentation of dorsal pattern extends from nape to occipital and parietal regions; (17) 22– 33 (mean 5 29) rhomboid dorsal body blotches that often coalesce with lateral blotches at midbody to form bands or chevrons (dorsal blotches of some specimens may become diffuse posteriorly, represented by barely distinct or absent bands anterior to vent); (18) light medial spots longer than wide on anterior portion of body, becoming broader at midbody and separating dorsal blotches; (19) medial spots often become indistinguishable from ground color on posterior one-quarter of body; (20) two white or light grey, irregular paraver- tebral spots present within each dorsal blotch, usually separated by 1–6 dorsal scale rows on anterior portion of body, but darken slightly and grow to extend across midline of dorsum to fill interior of dorsal blotches on posterior half of body; (21) tail black or dark brown with faint crossbands sometimes visible; (22) proximal rattle segment black or dark brown (Tables 6–7; from ANDERSON & GREENBAUM 2012).|
|Comment||Synonymy: Crotalus ornatus was revalidated from the synonymy of C. molossus by Anderson & Greenbaum 2012, hence C. ornatus has been subsumed under C. molossus in the older literature.|