Pseudoeryx relictualis SCHARGEL, RIVAS-FUENMAYOR, BARROS, PÉFAUR & NAVARETTE, 2007
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Pseudoeryx relictualis
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| Higher Taxa | Colubridae (Dipsadinae), Colubroidea, Caenophidia, Alethinophidia, Serpentes, Squamata (snakes) |
| Subspecies | |
| Common Names | E: South American Pond Snake |
| Synonym | Pseudoeryx relictualis SCHARGEL, RIVAS-FUENMAYOR, BARROS, PÉFAUR & NAVARETTE 2007 Pseudoeryx relictualis — WALLACH et al. 2014: 602 |
| Distribution | NW Venezuela (Zulia: Maracaibo Basin) Type locality: Hacienda La Trinidad, sector Montalbán, Municipio Catatumba, Zulia state, Venezuela, 09° 09’ 01” N, 72° 02’ 29” W. |
| Reproduction | ovovivparous |
| Types | Holotype: CVULA IV 6955 |
| Diagnosis | Diagnosis: The new species is placed in the genus Pseudoeryx because of having the nasal scales in contact with each other, separating the single internasal from the rostral scale, in combination with smooth dorsal scales in 15 rows at midbody. It can be distinguished from the only other species in the genus, Pseudoeryx plicatilis (character states in parentheses), by having a nuchal band (absent), a ventral color pattern of paired black spots encompassing the lateral edges of the ventral scales and the first row of dorsals, forming parallel sawtoothed stripes (venter with spots or dark mottling not forming sawtoothed stripes; see Fig. 4 for illustration of this character in both species), and having the anterior pair of genials noticeably shorter than the posterior pair, about 64–70% of the length of the posterior pair (both pairs of genials appearing subequal or having the first pair noticeably longer than the posterior pair; anterior genials 90–130% length of posterior pair). Additionally, specimens of the new species have the last two posterior maxillary teeth notably enlarged and separated from the rest by a diastema, whereas in all specimens of P. plicatilis examined there is no diastema and the two posterior teeth are not differentiated. Regrettably, most accounts of P. plicatilis do not provide information on dentition. Pseudoeryx relictualis is likely sympatric with Helicops scalaris, which is another aquatic colubrid snake found in the Lake Maracaibo Basin. Although these two species are superficially similar they differ in many aspects of their morphology (characters in parentheses are for P. relictualis and H. scalaris, respectively) such as number of dorsal scales rows at midbody (15 vs. 19–21), dorsal scale texture (smooth vs. keeled), and color pattern (brown or gray dorsum with a wide, lateral dark stripe vs. gray dorsum with dark blotches and or crossbands, some of which may be interconnected); therefore, even if individuals of these species are observed in the field but are not collected the differences in scale texture and color pattern should suffice to distinguish them. |
| Comment | |
| Etymology | Named after the Latin word relictus, meaning "abandoned or forsaken", and the Latin adjective-forming suffix -alis, meaning "pertaining to". The name alludes to the hypothetical scenario in which the ancestral stock of the new species was "abandoned" by the paleo-Orinoco River in the Maracaibo Lake Basin. |
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