Cyclocoridae Explained

Cyclocoridae is a family of elapoid snakes endemic to the Philippines.^[1]

Taxonomy

It was initially erected as a subfamily (Cyclocorinae) in 2017 to house four enigmatic, endemic genera containing seven species and one then-undescribed lineage that are more closely related to one another than to members of the families Atractaspididae or to other former subfamilies of the Lamprophiidae. The undescribed lineage was described in 2020 as the new genus Levitonius.

Previously placed within the Colubridae, a 2017 study by Weinell et al. found strong support the monophyly of Cyclocorinae within Lamprophiidae, but its position relative to the other subfamilies of Lamprophiidae is not resolved. Cyclocorinae was found to be a possible sister group to the Atractaspidinae. In 2019, they were reclassified as a distinct family Cyclocoridae, alongside many former members of Lamprophiidae, as Lamprophiidae was found to be otherwise paraphyletic with respect to Elapidae.^[2]

The Cyclocoridae likely began to diverge from their closest relatives, the Atractaspididae, beginning 35-40 million years ago (late Eocene). All extant genera within the family had diverged by the early Oligocene, and all extant species had evolved by the Miocene. Because snakes of this subfamily are not known from Palawan Island, their method of dispersal from mainland Asia to the Philippine archipelago must have differed from that of most Philippine reptiles and amphibians, which are thought to have rafted over on the Palawan "Ark".^{[3] [4] [5]}

The members of this subfamily are among the most poorly known snakes in the world. Very little information is available on their geographic distribution, ecology, behavior, or conservation status.^[6] Despite high support for a close relationship from DNA, no unambiguous morphological characteristics unite these four genera.

Genera and species

The five genera, three with two species each and two with one species, are:

• Genus Cyclocorus
  • C. lineatus
  • C. nuchalis
• Genus Levitonius^[7]
  • L. mirus
• Genus Hologerrhum
  • H. philippinum
  • H. dermali
• Genus Myersophis
  • M. alpestris
• Genus Oxyrhabdium
  • O. leporinum
  • O. modestum

Notes and References

1. Weinell JL, Brown RM . Discovery of an old, archipelago-wide, endemic radiation of Philippine snakes . Molecular Phylogenetics and Evolution . 119 . 144–150 . February 2018 . 29162550 . 10.1016/j.ympev.2017.11.004 . free .
2. Zaher H, Murphy RW, Arredondo JC, Graboski R, Machado-Filho PR, Mahlow K, Montingelli GG, Quadros AB, Orlov NL, Wilkinson M, Zhang YP, Grazziotin FG . 6 . Large-scale molecular phylogeny, morphology, divergence-time estimation, and the fossil record of advanced caenophidian snakes (Squamata: Serpentes) . PLOS ONE . 14 . 5 . e0216148 . 2019-05-10 . 31075128 . 6512042 . 10.1371/journal.pone.0216148 . 2019PLoSO..1416148Z . free .
3. Blackburn DC, Bickford DP, Diesmos AC, Iskandar DT, Brown RM . An ancient origin for the enigmatic flat-headed frogs (Bombinatoridae: Barbourula) from the islands of Southeast Asia . PLOS ONE . 5 . 8 . e12090 . August 2010 . 20711504 . 2918512 . 10.1371/journal.pone.0012090 . free . 2010PLoSO...512090B .
4. Brown RM, Su YC, Barger B, Siler CD, Sanguila MB, Diesmos AC, Blackburn DC . Phylogeny of the island archipelago frog genus Sanguirana: Another endemic Philippine radiation that diversified 'Out-of-Palawan' . Molecular Phylogenetics and Evolution . 94 . Pt B . 531–536 . January 2016 . 26477738 . 10.1016/j.ympev.2015.10.010 .
5. Siler CD, Oaks JR, Welton LJ, Linkem CW, Swab JC, Diesmos AC, Brown RM. Did geckos ride the Palawan raft to the Philippines?. Journal of Biogeography. 2012. 39. 7. 1217–1234. 10.1111/j.1365-2699.2011.02680.x. 10537899. 2018-05-13. 2018-05-14. https://web.archive.org/web/20180514065643/http://www.cameronsiler.com/PDFs/2012.Siler.etal.Gekko.J.Biogeog.pdf. dead.
6. Leviton AE, Siler CD, Weinell JL, Brown RM . Synopsis of the snakes of the Philippines: a synthesis of data from biodiversity repositories, field studies, and the literature. Proceedings of the California Academy of Sciences. 2018. 64. 399–468.
7. Weinell JL, Paluh DJ, Siler CD, Brown RM . 23 December 2020. A New, Miniaturized Genus and Species of Snake (Cyclocoridae) from the Philippines. Copeia. 108. 4. 907–923. 10.1643/CH2020110. 0045-8511. free. See also
   • Scientists Find Remarkable New Snake Species in Philippines. On: sci-news. Dec 24, 2020.