Ialtris Cope, 1862

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: 19

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Ialtris Cope, 1862


Genus Ialtris Cope, 1862 

Type species. Philodryas dorsalis Günther, 1858: 126  .

Diagnosis. Species in this genus have 19 midbody scale rows, 132–192 ventrals, 40–115 subcaudals, zero or two apical scale pits, seven upper labials, 8–9 lower labials, 18–19 total maxillary teeth, and 20–24 dentary teeth ( Table 2). Ialtris  differs in at least one of these characters from all other alsophiine genera except Hypsirhynchus  . In most Ialtris  , maxillary teeth are grooved whereas in Hypsirhynchus  (as in other alsophiines) they are ungrooved; in I. haetianus  they are ungrooved. Also, most Hypsirhynchus  have eight upper labials whereas Ialtris  has seven upper labials; the small Jamaican Hypsirhynchus  ( H. callilaemus  , H. funereus  , and H. polylepis  ) have seven upper labials ( Table 2).

Content. Four species (six species + subspecies) are included in the genus ( Table 1).

Distribution. The genus is distributed on Hispaniola ( Fig. 2View FIGURE 2).

Remarks. Ialtris  ( Fig. 3View FIGURE 3 E) includes the former Genus Darlingtonia  with its single species ( A. haetianus  ) and three subspecies (the haetianus  Group) and the three species in the genus Ialtris  (the dorsalis  Group) ( Table 1). Besides the strong molecular support for the monophyly of this genus, there is some morphological support as well. All four species of the Genus Ialtris  have seven upper labials, a rare number found only in the three species of the callilaemus  group ( Jamaica) of the genus Hypsirhynchus  , among other members of the Subtribe Alsophiina (which otherwise have eight). Also, two species of the genus Ialtris  ( A. agyrtes  and A. haetianus  ) lack apical scale pits; such pits are present in the genera Alsophis  , Borikenophis  , and Cubophis  , and absent in the Genus Magliophis  . Thus, the Genus Ialtris  is separable from all other genera of Alsophiina except Hypsirhynchus  . Relationships among the genera of the Subtribe Alsophiina are not well-resolved ( Fig. 1View FIGURE 1. A), and it might be that these two genera ( Ialtris  and Hypsirhynchus  ) occurring on Hispaniola are closest relatives.