Thursday, November 23, 2017

[Herpetology • 2018] Cyclocorinae (New Subfamily) • Discovery of An Old, Archipelago-wide, Endemic Radiation of Philippine Snakes

Subfamily Cyclocorinae

 Weinell & Brown, 2017.

• Three snake genera placed into molecular phylogeny for first time
• Hypothesized close relationship between Myersophis and Oxyrhabdium confirmed
• Hypothesized close relationship between Cyclocorus and Hologerrhum confirmed
• Novel, Philippine-endemic clade of snakes described as new subfamily Cyclocorinae
• Diversification within Cyclocorinae inconsistent with Pleistocene “species-pump”

The extraordinarily rich land vertebrate biodiversity of the Philippines includes at least 112 species of terrestrial snakes (74% of which are endemic to the archipelago) in 41 genera (12% endemic). Endemic Philippine snake genera include Cyclocorus (two species), Hemibungarus (three species), Hologerrhum (two species), Oxyrhabdium (two species), and Myersophis (monotypic). Although Hemibungarus and Oxyrhabdium have been included in previous species-level phylogenies, the affinities of the other three Philippine endemic genera are completely unknown. We generated novel DNA sequences for six species from four genera and analyzed these in conjunction with data from earlier studies to infer a phylogeny for the group containing Colubridae, Elapoidea (Elapidae + Lamprophiidae), and Homalopsidae. We present a novel phylogenetic result that strongly supports the existence of an entirely endemic Philippine radiation of elapoid snakes that originated 35–25 million years ago. We provide a revised, phylogeny-based classification to accommodate the new clade, transfer CyclocorusHologerrhum, and Myersophis to Lamprophiidae, and provide the first estimate of the evolutionary relationships among these genera and the related Oxyrhabdium, setting the stage for future investigation of this entirely endemic, novel Philippine elapoid radiation.

Keywords: Cyclocorinae; CyclocorusHologerrhum; Lamprophiidae; MyersophisOxyrhabdium

Representative taxa of the Philippine elapoid radiation, subfamily Cyclocorinae: 
Myersophis alpestris (holotype, KU 203012),  Oxyrhabdium modestum (RMB 19937),Cyclocorus lineatus (KU 275744), Oxyrhabdium leporinum leporinum (KU 322339)

[map] Geographic distribution of Cyclocorinae new subfamily in the Philippines, including Cyclocorus, Hologerrhum, Myersophis, Oxyrhabdium, and the unnamed lineage.

Fig. 1. Representative taxa of the Philippine elapoid radiation, subfamily Cyclocorinae:
(A) Oxyrhabdium leporinum leporinum (KU 322339), (B) Oxyrhabdium leporinum visayanum, (C) Oxyrhabdium modestum (Uncataloged KU specimen [RMB 19937]), (D) Hologerrhum philippinum (KU 330056), (E) Cyclocorus lineatus (KU 275744), (F) Cyclocorus nuchalis (KU 344159), (G) and (H) Myersophis alpestris (holotype, KU 203012).

Cyclocorinae (new subfamily)

Type genus: Cyclocorus Duméril, Bibron, and Duméril, 1854
Type species: Lycodon lineatus Reinhardt, 1843

Content: Cyclocorinae includes four endemic Philippine genera:
Genus CyclocorusCyclocorus lineatus lineatusC. l. alcalaiC. nuchalis nuchalis and C. n. taylori.
Genus HologerrhumHologerrhum philippinum and H. dermali.
Genus OxyrhabdiumOxyrhabdium leporinum leporinum, O. l. visayanum and O. modestum.
Genus MyersophisMyersophis alpestris.

Jeffrey L. Weinell and Rafe M. Brown. 2018. Discovery of An Old, Archipelago-wide, Endemic Radiation of Philippine Snakes. Molecular Phylogenetics and Evolution. In Press.   DOI: 10.1016/j.ympev.2017.11.004