Systematics of South American snail-eating snakes (Serpentes, Dipsadini), with the description of five new species from Ecuador and Peru

Abstract

A molecular phylogeny of the Neotropical snail-eating snakes (tribe Dipsadini) is presented including 43 (24 for the first time) of the 77 species, sampled for both nuclear and mitochondrial genes. Morphological and phylogenetic support was found for four new species of Dipsas and one of Sibon, which are described here based on their unique combination of molecular, meristic, and color pattern characteristics. Sibynomorphus is designated as a junior subjective synonym of Dipsas. Dipsas latifrontalis and D. palmeri are resurrected from the synonymy of D. peruana. Dipsas latifasciata is transferred from the synonymy of D. peruana to the synonymy of D. palmeri. A new name, D. jamespetersi, is erected for the taxon currently known as Sibynomorphus petersi. Re-descriptions of D. latifrontalis and D. peruana are presented, as well as the first photographic voucher of an adult specimen of D. latifrontalis, along with photographs of all known Ecuadorian Dipsadini species. The first country record of D. variegata in Ecuador is provided and D. oligozonata removed from the list of Peruvian herpetofauna. With these changes, the number of Dipsadini reported in Ecuador increases to 22, 18 species of Dipsas and four of Sibon.

Dipsas vermiculata Peters, 1960 (Squamata, Colubridae): first country record from Colombia, with description of its hemipenial morphology and comments on its distribution and diagnosis

“…The record of the specimen SBH 171139 from Pasco, Peru, incorrectly listed as "SBI 171139" by Arteaga et al (2018), was excluded from the locality records of D. vermiculata (Appendix Table A1) because (1) the locality suggests an enormous distribution gap of more than 760 km in a straight line in relation to southernmost records from Ecuador and Peru; (2) the specimen appears initially referenced as D. catesbyi (Sentzen, 1796) by Heise et al (1995); (3) it was not examined and the change of its identity to D. vermiculata is only based on DNA sequence analyses; (4) this change was apparently influenced by an inadequate comparison where sequences of 12S gene are lacking for several species of Dipsas including the most closely related and/or similar ones such as D. pakaraima MacCulloch &Lathrop, 2004, D. pavonina Schlegel, 1837, andD. temporalis (Werner, 1909) (see Arteaga et al 2018: appendix 1); and (5) the 12S and 16S gene sequences (GenBank accession numbers Z46459 and Z46496, respectively) associated with specimen SBH 171139 by Arteaga et al (2018), actually belong to two different specimens (see Material and Methods in Heise et al 1995).…”

“…Species identification is based on the original description by Peters (1960) as well as additional characteristics provided by Harvey and Embert (2008), Arteaga et al (2018), and distinguishable details of several specimens photographed in life from the Museo de Zoología of the Pontificia Universidad Católica del Ecuador (QCAZ), compiled by Pazmiño-Otamendi and Rodríguez-Guerra (2019). Locality records were also taken from the aforementioned sources in addition to The Global Biodiversity Information Facility (GBIF Secretariat 2019), especially from datasets provided by Harvard University and Senckenberg (Harvard University and Morris 2019; Senckenberg 2019).…”

“…The snail-eating snakes of the genus Dipsas Laurenti, 1768 are distributed in Latin America from Mexico to all South American countries, except Chile (Peters 1960;Peters and Orejas-Miranda 1970;Savage 2002;Wallach et al 2014). In the latest systematic hypothesis of South American Dipsadini (Arteaga et al 2018), mainly based on molecular analyses, the genus Sibynomorphus Fitzinger, 1843 was considered a synonym of Dipsas. This, in addition to other taxonomic actions and new species described from Ecuador and Peru, led to 52 species currently comprised within the genus (Arteaga et al 2018;Uetz et al 2019).…”

“…In the latest systematic hypothesis of South American Dipsadini (Arteaga et al 2018), mainly based on molecular analyses, the genus Sibynomorphus Fitzinger, 1843 was considered a synonym of Dipsas. This, in addition to other taxonomic actions and new species described from Ecuador and Peru, led to 52 species currently comprised within the genus (Arteaga et al 2018;Uetz et al 2019).…”

“…This species was initially assigned to the D. catesbyi species group mainly based on coloration pattern features (Peters 1960), but Harvey (2008) included it into the D. temporalis species group based on additional visceral morphology and scutellation features. Finally, Arteaga et al (2018) transferred D. vermiculata into the D. variegata species group based exclusively on the results of their molecular analyses.…”