Cyclocoridae is a

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

of elapoid

snake Snakes are elongated, limbless, carnivorous reptiles of the suborder Serpentes . Like all other squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with several more j ...

s endemic to the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

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 The Atractaspididae (atractaspidids) are a family of venomous snakes found in Africa and the Middle East, commonly called mole vipers, stiletto snakes, or burrowing asps. Currently, 12 genera are recognized. Description This family includes man ...

or to other former subfamilies of the

Lamprophiidae The Lamprophiidae are a family of snakes found throughout much of Africa, including the Seychelles. There are 89 species as of July 2022. Biology Lamprophiids are a very diverse group of snakes. Many are terrestrial but some are fossorial (e.g. ...

. The undescribed lineage was described in 2020 as the new genus '' Levitonius''. Previously placed within the

Colubridae Colubridae (, commonly known as colubrids , from la, coluber, 'snake') is a family of snakes. With 249 genera, it is the largest snake family. The earliest species of the family date back to the Oligocene epoch. Colubrid snakes are found on ev ...

, a 2017 study by Weinell et al. found strong support the

monophyly In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gr ...

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 In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

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 In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...

with respect to

Elapidae Elapidae (, commonly known as elapids ; grc, ἔλλοψ ''éllops'' "sea-fish") is a family of snakes characterized by their permanently erect fangs at the front of the mouth. Most elapids are venomous, with the exception of the genus Emydoce ...

. The Cyclocoridae likely began to diverge from their closest relatives, the Atractaspididae, beginning 35-40 million years ago (late

Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ...

). All extant genera within the family had diverged by the early

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but ...

, and all extant species had evolved by the

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" ...

. Because snakes of this subfamily are not known from

Palawan Island Palawan is the largest island of the province of Palawan in the Philippines and fifth-largest by area and tenth-most populous island of the country, with a total population of 994,101 as of 2020 census. The north west coast of the island is alon ...

, 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". 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. 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'' See also
Scientists Find Remarkable New Snake Species in Philippines
On: sci-news. Dec 24, 2020. ** ''L. mirus'' * Genus '' Hologerrhum'' ** ''H. philippinum'' ** ''H. dermali'' * Genus ''

Myersophis ''Myersophis'' is a genus of snake in the family Cyclocoridae. It contains only one species, ''Myersophis alpestris'' or Myers' mountain snake, which is endemic to the Philippines. It is only known from two specimens collected near Banaue from M ...

'' ** ''M. alpestris'' * Genus '' Oxyrhabdium'' ** ''O. leporinum'' ** ''O. modestum''

Gallery

File:Cyclocorus lineatus lineatus (KU 326690) from Barangay Dibuluan, San Mariano - ZooKeys-266-001-g081.jpg, ''Cyclocorus''

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen( ...

; Reinhardt's lined snake ( ''C.'' ''lineatus'') File:Closeup of Hologerrhum philippinum (KU 33056) - ZooKeys-266-001-g087.jpg, ''Hologerrhum'' type species; Philippine stripe-lipped snake ( ''H.'' ''philippinum'') File:Oxyrhabdium modestum.jpg, ''Oxyrhabdium'' type species; Philippine shrub snake ( ''O.'' ''modestum'')

References

{{Taxonbar, from=Q55608735 Cyclocoridae