Crotalus unicolor LIDTH DE JEUDE, 1887
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Crotalus unicolor
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| Higher Taxa | Viperidae, Crotalinae, Colubroidea, Caenophidia, Alethinophidia, Serpentes, Squamata (snakes) |
| Subspecies | |
| Common Names | E: Aruba Island Rattlesnake G: Aruba-Klapperschlange |
| Synonym | Crotalus horridus var. unicolor LIDTH DE JEUDE 1887: 133 Crotalus unicolor — KLAUBER 1936: 190 Crotalus durissus unicolor — DAAN & HILLENIUS 1966: 137 Crotalus unicolor — MCCRANIE 1986 Crotalus durissus unicolor — CAMPBELL & LAMAR 1989 Crotalus durissus unicolor — WELCH 1994: 45 Crotalus durissus unicolor — MCDIARMID et al. 1999 Crotalus durissus unicolor — CAMPBELL & LAMAR 2004 Crotalus durissus unicolor — QUIJADA-MASCAREÑAS & WÜSTER 2006 Caudisona unicolor — HOSER 2009 Crotalus unicolor — MARITZ et al. 2016 Crotalus unicolor — ZAHER et al. 2019 |
| Distribution | Aruba Island (off the coast of Venezuela) Type locality: “Aruba” |
| Reproduction | ovovivparous. Schuett et al. (1997) provide evidence for parthenogenesis in this C. d. unicolor. |
| Types | Holotype: RMNH 613 |
| Diagnosis | DIAGNOSIS. Crotalus unicolor is a stunted species related to C. durissus, ranging in size from about 230 mm at birth to 970 mm in the largest known specimen. Adults are pale gray or pale grayish brown dorsally with faint or nearly indistinguishable dorsal rhombs. Longitudinal stripes on the rear part of the head and on the neck are faintly evident in some adults and indistinguishable in others. When evident, the dorsal rhombs number 18 to 28. The venter is white or cream-colored. The tail is darker gray than the body. Juveniles have distinct dorsal rhombs and longitudinal stripes on the rear part of the head and on the neck. Traces of a frontal crossbar, a dark supraocular stripe, and 5-6 caudal crossbands are evident in some juveniles. All of these markings fade with age. Scutellation is as follows: 25-27 (usually 27) scale rows at midbody, all keeled except for the lowest 1-3; 155-164 ventrals in males, 163-169 in females; 26-31 subcaudals in males, 22-25 in females; 11-15 supralabials; 12-16 infralabials (first frequently divided); 2 preoculars. The rostral is triangular and higher than wide. The internasals are paired. The prefrontals are paired, in contact medially, and are larger than the internasals. Posterior to the prefrontals (frontal area) there are two large scales bordered posteriorly by smaller irregular scales in rows. Posterior to these irregular scales there is a pair of larger scales (vestiges of parietals) bordering the supraoculars. The remainder of the head is covered by small and fairly regular scales. The first supralabial contacts the prenasal. There are 1-3 loreals on each side of the head. A vertebral ridge is present in adults but is less pronounced than in Crotalus durissus. Crotalus unicolor differs from C. durissus in that the dorsal rhombs and the pair of longitudinal stripes present on the head and neck of durissus are largely absent in adult unicolor because of a faded color pattern. Crotalus unicolor is also a smaller species than durissus, with the largest known specimen of unicolor 970 mm in total length. Crotalus unicolor differs from C. vegrandis, another stunted species closely related to durissus, in that the latter has numerous scattered white-tipped scales on the head and body. (McCranie 1986) |
| Comment | Venomous! Synonymy: Reyes-Velasco et al. 2022 failed to recover C. simus, C. unicolor and C. vegrandis as distinct from C. durissus (using DELINEATE, a relatively new species delimitation method). |
| Etymology | Named after Latin uni (meaning one) and color (meaning color), refering to the faded color pattern of the species. |
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