''Cenaspis aenigma'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

colubrid 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 ...

snake in the subfamily

Dipsadinae Dipsadinae is a large subfamily of colubroid snakes, sometimes referred to as a family (Dipsadidae). They are found in most of the Americas, including the West Indies, and are most diverse in South America. There are more than 700 species. Dips ...

and the only member of the

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 "unispe ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

''Cenaspis.'' It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

to the highlands of western Chiapas,

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

, where it was described from a single, partially digested male specimen found in the stomach of a Central American coral snake (''

Micrurus nigrocinctus ''Micrurus nigrocinctus'', Common name, commonly known as the Central American coral snake, is a species of a highly venomous snake in the Family (biology), family Elapidae. The species is Endemism, endemic to Latin America from southern Mexico, ...

''). This is referenced in its

generic Generic or generics may refer to: In business * Generic term, a common name used for a range or class of similar things not protected by trademark * Generic brand, a brand for a product that does not have an associated brand or trademark, other ...

name, as ''cena'' is

Spanish Spanish might refer to: * Items from or related to Spain: **Spaniards are a nation and ethnic group indigenous to Spain **Spanish language, spoken in Spain and many Latin American countries **Spanish cuisine Other places * Spanish, Ontario, Can ...

for "dinner". Despite being partially digested, the specimen still displayed many unique traits, including undivided

subcaudals In snakes, the subcaudal scales are the enlarged plates on the underside of the tail.Wright AH, Wright AA. 1957. Handbook of Snakes. Comstock Publishing Associates (7th printing, 1985). 1105 pp. . These scales may be either single or divided (pair ...

for the full length of the tail, as well as a simple

hemipenis A hemipenis (plural hemipenes) is one of a pair of intromittent organs of male squamates (snakes, lizards and worm lizards). Hemipenes are usually held inverted within the body, and are everted for reproduction via erectile tissue, much like ...

completely covered in calyces with a largely non-bifurcated sulcus spermaticus. These traits are not known from any other colubroid snake in the

Western Hemisphere The Western Hemisphere is the half of the planet Earth that lies west of the prime meridian (which crosses Greenwich, London, United Kingdom) and east of the antimeridian. The other half is called the Eastern Hemisphere. Politically, the te ...

Description

Dorsally Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

, ''C. aenigma'' is uniformly pale brown. Ventrally, it is whitish with three dark stripes running the length of the belly on the

ventrals In snakes, the ventral scales or gastrosteges are the enlarged and transversely elongated scales that extend down the underside of the body from the neck to the anal scale. When counting them, the first is the anteriormost ventral scale that cont ...

, and one dark stripe running the length of the tail in the center of the subcaudals. The total length (including tail) of the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ...

is .Campbell et al. (2018).

Description

References

Further reading