Tuesday, January 3, 2017

Rhynchocalamus a poorly known clade of snakes from southwest Asia

The colubrid snake genus Rhynchocalamus composed of three small, gracile snakes distributed in Southwest Asia. While, these snakes are sometimes called Kikuri snakes, a name sometimes applied to the members of the genus Oligodon, they also tend to have blackheads and are sometimes called the blackheaded snakes, a name that may confuse them with the North American genus Tantilla. Their secretive fossorial lifestyle has resulted in them being poorly known and under studied. Only recently Šmíd et al. (2015) found Rhynchocalamus to be a member of the the Western Palearctic clade of Colubrinae and the sister to the awl-headed snakes of the genus  Lytorhynchus.

Three species of Rhynchocalamus are currently recognized, R. satunini (Turkey eastwards to Iran), R. arabicus (Yemen and Oman), and R. melanocephalus (from the Sinai Peninsula northwards to Turkey). Tamar et al. (2016) recently completed a comprehensive study on all known Rhynchocalamus species in order to review the intra-generic phylogenetic relationships and historical biogeography of the genus and describe a fourth species from Israel.

The molecular results found Rhynchocalamus monophyletic, and last shared an ancestor with Lytorhynchus in Late Oligocene. The three recognized species of Rhynchocalamus comprise four independently lineages with the genus diverge during the Middle Miocene. They discovered R. melanocephalus is paraphyletic. A population from the Negev Mountain area in southern Israel is phylogenetically closer to R. arabicus from Oman than to the northern populations of the species from Israel, Syria and Turkey and they describe this population as the new species Rhynchocalamus dayanae.

A) R. dayanae sp. nov. specimen from  Mitzpe Ramon, Negev Mountain, Israel; photo by Simon Jamison); (B) R. melanocephalus (Tartus, Syria; photo by Bayram Göçmen); (C) R. satunini (Artuklu, Mardin province, Turkey; photo by Bayram Göçmen); (D) R. arabicus (Wadi Ayoun, Dhofar Governorate, Oman; photo by Gabriel Martínez).

Citations

Šmíd, J;  Martínez G, Gebhart J, Aznar J,  Gállego J, Göçmen B, De Pous P, Tamar K & Carran-za S. 2015. Phylogeny of the genus Rhynchocalamus (Reptilia; Colubridae) with a first record from the Sultanate of Oman Zootaxa 4033 (3): 380–392.

Tamar K, Šmíd J, Göçmen B, Meiri S, Carranza S. (2016) An integrative systematic revision and biogeography of Rhynchocalamus snakes (Reptilia, Colubridae) with a description of a new species from Israel. PeerJ 4:e2769 https://doi.org/10.7717/peerj.2769.

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