False coral snakes

(Aniliidae)

Class Reptilia

Order Squamata

Suborder Serpentes

Family Aniliidae

Thumbnail description
Moderately sized Amazonian snakes with a cylindrical body of uniform diameter, very short tail and a blunt, slightly flattened head not demarcated from the body; body has smooth scales, a ground color of pink or red with 50–60 black bands or half bands, each two to four scales long, distributed evenly down the trunk

Size
2–3 ft (0.6–1 m) total length

Number of genera, species
1 genus; 1 species

Habitat
Rainforest and riparian lowland areas

Conservation status
Data Deficient

Distribution
Amazon Basin of eastern Peru and Ecuador, southern Colombia, northern Bolivia, and Brazil

Evolution and systematics

The evolutionary origin of aniliids remains obscure. Fossil vertebrae ascribed to this family have been recovered from Cretaceous deposits in Wyoming and New Mexico. These fossils look superficially like the vertebrae of living aniliids except for two features of the neural arch that are more similar to those found in living scolecophidian snakes. Much of the older literature uses the term "aniliid" to refer to all basal alethinophidian lineages. Hence, it is unclear whether many of these data actually apply to Aniliidae sensu stricto. Recent phylogenetic analyses have produced conflicting results with respect to the relationships of aniliids, although most analyses place aniliids closest to the anomochilid-uropeltid-cylindrophiid lineages. Aniliids are therefore one of a group of relict, basal alethinophidian taxa.

The family contains a single species that has been divided into two subspecies based on ventral counts and the relative lengths of black and red rings on the body. The northern (Venezuelan) subspecies A. scytale phelpsorum is purported to have fewer than 225 ventrals and have black bands longer than the red bands, whereas the subspecies occupying the remainder of the family's range, A. scytale scytale, has more than 225 ventrals and has black bands shorter than the red bands. Specimens with characteristics of both subspecies have been found in northern Brazil and French Guiana. No subfamilies are recognized.

Physical characteristics

Among the features denoting the basal position of aniliids are the tiny eyes covered by one of the larger head scales (as in uropeltids) rather than a differentiated spectacle, as in most other snakes. Externally, these snakes have a superficial resemblance to the pipe snakes of Southeast Asia and to some of the venomous coral snake species of the Amazon Basin, being red or pink with about 50 black bands distributed evenly down the trunk. They have smooth, shiny scales in 15 (precloacal) to 21 (midbody) rows and the ventrals are one and one-half to two times the width of the adjacent scale rows. Internally, they retain teeth on the premaxilla, a vestigial pelvic girdle capped by a cloacal spur, a small left lung, and paired carotid arteries. Their skulls have massive jaws with small numbers of relatively large, slightly recurved conical teeth.

Distribution

False coral snakes are found in the Amazon Basin of eastern Peru and Ecuador, southern Colombia, northern Bolivia, and Brazil. In the east and north their range includes French Guiana, Suriname, Guyana, and the southern Orinoco Basin of southeastern Venezuela.

Habitat

Rainforest and riparian lowland areas.

Behavior

Very little is known.

Feeding ecology and diet

Anilius feeds primarily on small, elongate vertebrates such as eels, amphisbaenians, caecilians, and other snakes.

Reproductive biology

Females give birth to up to 15 young.

Conservation status

This species is listed as Data Deficient by the IUCN, but it is probably threatened in many areas of its range by habitat destruction or modification.

Significance to humans

None known.

Resources

Books

Chippaux, J.-P. Les Serpents de la Guyane Francaise. Paris: Editions de l'ORSTOM, 1986.

Greene, H. W. Snakes: The Evolution of Mystery in Nature. Berkeley: University of California Press, 1997.

Peters, J. A., R. Donoso-Barros, and P. E. Vanzolini. Catalogue of the Neotropical Squamata. Part 1, Snakes. Washington, DC: Smithsonian Institution Press, 1986.

Roze, J. A. La Taxonomia y Zoogeografia de los Ofidios de Venezuela. Caracas: Ediciones de la Biblioteca, Univ. Central de Venezuela, 1966.

Zug, G. R., L. J. Vitt, and J. P. Caldwell. Herpetology: An Introductory Biology of Amphibians and Reptiles, 2nd ed. San Diego: Academic Press, 2001.

David Cundall, PhD