Dipsas andiana (BOULENGER, 1896)
Can you confirm these amateur observations of Dipsas andiana?
|Higher Taxa||Colubridae (Dipsadinae), Colubroidea, Caenophidia, Alethinophidia, Serpentes, Squamata (snakes)|
|Synonym||Leptognathus andiana BOULENGER 1896: 452|
Leptognathus variegata — STEINDACHNER 1902: 108 (misidentification)
Leptognathus andianus — FOWLER 1913: 169 (misidentifications)
Sibynomorphus andiana — PARKER 1926: 206
Sibynomorphus andianus — AMARAL 1929: 195
Dipsas variegata nicholsi — OLIVER 1955 (part)
Dipsas oreas — PETERS 1960 (part)
Dipsas andiana — CADLE & MYERS 2003
Dipsas andiana — WALLACH et al. 2014: 230
|Distribution||W Ecuador, elevation 5-1040 m (CADLE & MYERS 2003)|
Type locality: Quito, Ecuador [probably not the collection locality but rather the shipping point where the collector resided; see CADLE & MYERS 2003].
|Types||Holotype: BMNH 1922.214.171.124 (originally BMNH 126.96.36.199)|
|Diagnosis||DIAGNOSIS: Dipsas andiana is a pale brown or grayish snake with a distinctive contrasting pattern on the head and dorsum. The head is relatively unmarked except for a bold blackish brown n-shaped or inverted V-shaped marking extending from the anterior edge of the frontal to the neck (fig. 8). Dorsal markings consist of a series of large round, elliptical, or irregular dark blotches on each side, each with a narrow pale border. Corresponding blotches from each side occasionally meet middorsally, in which case there is a definite constriction at the vertebral scale row. Anteriorly, blotches tend to be opposite one another, whereas posteriorly they tend to alternate. Interspaces between the blotches are broader than the blotches (in some specimens 2–21/23) for the entire length of the body; anteriorly, the interspaces tend to be narrower than posteriorly. Dipsas andiana has a high number of ventrals (185–201) and subcaudals (5 males: 91–106; 4 females: 82–83).|
Other species of Dipsas in western Ecuador include D. gracilis, D. oreas auctorum (including D. [oreas] ellipsifera and D. [oreas] elegans; see Orcés and Almendáriz, 1987), and D. temporalis. These species lack the distinctive head marking of D. andiana, although they usually have extensive dark markings on the head. Dipsas gracilis and D. temporalis are similar to D. andiana in having high numbers of ventrals and subcaudals; however, these are distinctly banded snakes in which the bands are much broader than the interspaces, are not round or elliptical, and lack distinct pale borders. The bands in D. gracilis extend across the venter, whereas the blotches in D. andiana end on the lateral edges of the ventrals. Dipsas ellipsifera and D. elegans have narrow rectangular blotches or bands with light centers and straight edges (Peters, 1960: pl. 4a; Kofron, 1982: fig. 1).
Most D. oreas can easily be described as banded snakes, at least anteriorly,
whereas D. andiana is laterally blotched.
|Comment||Dipsas andiana has been resurrected by CADLE & MYERS (2003). Peters (1960: 92), without examining the type specimen, placed L. andiana in the synonymy of Dipsas oreas. He explained away some color pattern differences between L. andiana and typical D. oreas because the type specimen of L. andiana is a juvenile (Peters, 1960: 93–94). Peters was also perhaps misled because Boulenger, either through a counting error or misprint, gave an erroneous count of 184 ventrals for the type, a count at the upper extreme for D. oreas. However, the corrected count of 191 ventrals far exceeds the range we have observed for D. oreas.|