The Cylindrophiidae are a

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

of secretive, semifossorial, non-venomous

snakes Snakes are elongated Limbless vertebrate, limbless reptiles of the suborder Serpentes (). Cladistically Squamata, squamates, snakes are ectothermic, amniote vertebrates covered in overlapping Scale (zoology), scales much like other members of ...

containing the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

''Cylindrophis'' found in southeastern

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

. These are burrowing snakes and most have a banded pattern on the belly. Currently, 14

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

are recognized, all with no subspecies. Common names include Asian pipesnakes and Asian cylinder snakes.

Geographic range

''Cylindrophis'' are found in southeastern Asia from

Myanmar Myanmar, officially the Republic of the Union of Myanmar; and also referred to as Burma (the official English name until 1989), is a country in northwest Southeast Asia. It is the largest country by area in Mainland Southeast Asia and has ...

Laos Laos, officially the Lao People's Democratic Republic (LPDR), is the only landlocked country in Southeast Asia. It is bordered by Myanmar and China to the northwest, Vietnam to the east, Cambodia to the southeast, and Thailand to the west and ...

Vietnam Vietnam, officially the Socialist Republic of Vietnam (SRV), is a country at the eastern edge of mainland Southeast Asia, with an area of about and a population of over 100 million, making it the world's List of countries and depende ...

Cambodia Cambodia, officially the Kingdom of Cambodia, is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. It is bordered by Thailand to the northwest, Laos to the north, and Vietnam to the east, and has a coastline ...

Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...

, and the

Malay Archipelago The Malay Archipelago is the archipelago between Mainland Southeast Asia and Australia, and is also called Insulindia or the Indo-Australian Archipelago. The name was taken from the 19th-century European concept of a Malay race, later based ...

, including

Singapore Singapore, officially the Republic of Singapore, is an island country and city-state in Southeast Asia. The country's territory comprises one main island, 63 satellite islands and islets, and one outlying islet. It is about one degree ...

, both peninsular

Malaysia Malaysia is a country in Southeast Asia. Featuring the Tanjung Piai, southernmost point of continental Eurasia, it is a federation, federal constitutional monarchy consisting of States and federal territories of Malaysia, 13 states and thre ...

and

Sarawak Sarawak ( , ) is a States and federal territories of Malaysia, state of Malaysia. It is the largest among the 13 states, with an area almost equal to that of Peninsular Malaysia. Sarawak is located in East Malaysia in northwest Borneo, and is ...

, and

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...

, including the Greater Sunda Islands (Borneo [including

and Brunei]), Sumatra, and Java, as well as some of their offshore islands), Sulawesi, the Lesser Sunda Islands (Lombok, Komodo, Flores, Sumbawa, Timor [including Timor-Leste]), and east to the Maluku Islands (Halmahera, Wetar, Damar, Babar, and into the Tanimbar Archipelago). The eastern distributional limit, sometimes given as the Aru Islands off the southwestern coast of

New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; , fossilized , also known as Papua or historically ) is the List of islands by area, world's second-largest island, with an area of . Located in Melanesia in the southwestern Pacific Ocean, the island is ...

, is questionable. They are also found in

Sri Lanka Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka, also known historically as Ceylon, is an island country in South Asia. It lies in the Indian Ocean, southwest of the Bay of Bengal, separated from the Indian subcontinent, ...

(but not

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

) and in southeastern

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

(

Fujian Fujian is a provinces of China, province in East China, southeastern China. Fujian is bordered by Zhejiang to the north, Jiangxi to the west, Guangdong to the south, and the Taiwan Strait to the east. Its capital is Fuzhou and its largest prefe ...

Hong Kong Hong Kong)., Legally Hong Kong, China in international treaties and organizations. is a special administrative region of China. With 7.5 million residents in a territory, Hong Kong is the fourth most densely populated region in the wor ...

, and on

Hainan Island Hainan is an island province and the southernmost province of China. It consists of the eponymous Hainan Island and various smaller islands in the South China Sea under the province's administration. The name literally means "South of the Sea ...

Description

All members of the genus ''Cylindrophis'' share the following five characteristics: 1) a relatively blunt head, not distinct from the neck, with minute eyes and a mental groove; 2) the absence of well-developed ventral scales, with ventral scales only slightly larger than or equal in size to the dorsal scales; (3) the presence of a pair of

pelvic spur Pelvic spurs (also known as vestigial legs) are external protrusions found around the cloaca in certain superfamilies of snakes belonging to the greater infraorder ''Alethinophidia''.Pough, F. H. (Ed.). (2004). ''Herpetology'' (3rd ed). Prentice ...

s in both sexes; (4) a very short tail, often with conspicuous ventral coloration; and (5) contrasting light and dark ventral blotching. The body is cylindrical, with a near-uniform diameter, which leads to the name "pipe snakes". All species are small- to medium-sized, with total lengths ranging from 12.5 cm (5 inches) to 85.7 cm (34 inches). The teeth are moderate and subequal, with 10–12 in each

maxilla In vertebrates, the maxilla (: maxillae ) is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxil ...

and none in the

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammals h ...

. There are no fangs and no evidence of venom. The eyes have round or vertically subelliptic pupils. The head has large symmetrical shields, with the nostrils in a single nasal, which forms a suture with its fellow behind the rostral. Loreal scale is present, a small postocular scale is present. The dorsal scales are smooth, in 17, 19, 21, or 23 rows depending on the species.

Behavior and ecology

When threatened, ''Cylindrophis'' flatten the posterior portion of their body and arch it above the ground to display their conspicuous ventral pattern, while the head remains concealed among the body coils. Only one species, ''C. yamdena'', lacks a bold ventral pattern in most individuals, having instead an orange-pink belly without bands or spots. Little is known of the foraging or mating behavior of ''Cylindrophis''. At least one species uses constriction to subdue its prey, which include elongate vertebrates: reptiles (snakes), amphibians (caecilians), and fish (eels). Prey are swallowed from one end using rotational movements of the braincase and mandibles, a process that takes up to 30 minutes for larger prey. This is distinct from the 'pterygoid walk' used by most other species of

alethinophidia :''Common names: advanced snakes.'' The Alethinophidia are an infraorder of snakes that includes all snakes other than blind snakes and thread snakes. Snakes have long been grouped into families within Alethinophidia based on their morphology, e ...

n snakes, which have greater mobility of most skull bones than ''Cylindrophis''.

Species

The

''Cylindrophis'' contains the following 14

. ^T:

Type species In International_Code_of_Zoological_Nomenclature, 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 spe ...

Phylogenetic relationships

Many recent studies based on molecular data suggest that Cylindrophiidae may be paraphyletic with respect to another family of pipesnakes, Anomochilidae or dwarf pipesnakes. Probably this will be resolved by including Anomochilidae within Cylindrophiidae in the future, but as of May 2018 no formal proposal to do so has been made. In a broader sense, Cylindrophiidae & Anomochilidae are most closely related to

Uropeltidae The Uropeltidae, also Common name, commonly known as shield-tail snakes, shield-tailed snakes or earth snakes, are a Family (biology), family of primitive, nonvenomous, burrowing snakes native to Peninsular India and Sri Lanka. The name is derive ...

, a family of burrowing snakes from southern India & Sri Lanka. These three families are together called the Uropeltoidea and probably last shared a common ancestor in the

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

, about 45 million years ago. Uropeltoids are probably most closely related to pythonoids, and then to booids. These three groups probably last shared a common ancestor in the late

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

, about 75 million years ago.

References

External links

{{Authority control Snake genera Taxa named by Johann Georg Wagler