Alsophis Fitzinger, 1843

Hedges, Blair, Couloux, Arnaud & Vidal, Nicolas, 2009, Molecular phylogeny, classification, and biogeography of West Indian racer snakes of the Tribe Alsophiini (Squamata, Dipsadidae, Xenodontinae), Zootaxa 2067, pp. 1-28: 13

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Alsophis Fitzinger, 1843


Genus Alsophis Fitzinger, 1843 

Type species. Psammophis antillensis Schlegel, 1837: 214  .

Diagnosis. Species in this genus have 19–23 midbody scale rows, 184–220 ventrals, 94–138 subcaudals, two apical scale pits, eight upper labials, 10 lower labials, 18–21 maxillary teeth, and 21–26 dentary teeth ( Table 2). Alsophis  differs in at least one of these characters from all alsophiine genera except Borikenophis  and Hypsirhynchus  . Alsophis  differs almost completely from Hypsirhynchus  in ventrals (184–220 versus 123–189 in Hypsirhynchus  ). It differs from most Borikenophis  (163–187), except for B. sanctaecrucis  (191–198), in having a higher number of ventrals (184–220).

Content. Eight species (nine species + subspecies) are included in the genus ( Table 1).

Distribution. The genus is distributed in the northern Lesser Antilles ( Fig. 2 View Figure ).

Remarks. Species of Alsophis  are moderate-sized (1080 mm, maximum SVL) racers ( Fig. 3 View Figure A). They are all endemic to islands in the northern Lesser Antilles, from Anguilla to Dominica ( Fig. 2 View Figure ). These northern islands are sometimes referred to as the “Leeward” islands. Within the genus, two well-supported geographic groups are present ( Figs. 1 View Figure and 4 View Figure ) for which we propose species groups. The rufiventris  Group comprises species from the northernmost Leeward islands of Anguilla to Antigua ( A. antiguae  , A. rijgersmaei  , A. rufiventris  , and A. sajdaki  ). Within this group, we lacked A. antiguae  which is possibly extinct (Henderson et al. 1996), but it is closest to A. sajdaki  , morphologically. The rufiventris  Group is also supported by a hemipenial character ( Zaher 1999). The antillensis  Group comprises species from Montserrat to Dominica ( A. antillensis  , A. manselli  , A. sanctonum  , and A. sibonius  ), the southern Leeward islands. We did not sample A. sanctonum  , but it shares a unique hemipenial character with A. sibonius ( Zaher 1999)  , and we assume the two species to be closely related. A comprehensive review of the morphology of Lesser Antillean alsophiines is needed.