Leptotyphlopidae
Leptotyphlopidae comprises about 90 species in two genera (Leptotyphlops and Rhinoleptis). They have a tropical distribution, and are found in tropical North and South America, Africa, and the Middle East and northwest India. They live in a variety of habitats, from rainforests to semideserts, and from termite burrows to trees tops.
Leptotyphlopids are small and very slender snakes, with a maximum recorded total length of 40cm but more typically attaining lengths of 15-20cm. Like other blindsnakes, the eyes of anomalepedids are vestigial and covered by scales. The highly flexible dentaries posses four or five teeth, although teeth are absent form the immobile maxillae. The hyobranchium is Y-shaped. The left lung is absent (as it is in most snakes), as is a tracheal lung. Some species retain rather well developed pelvic elements, including paired ilia, ischia, pubes, and femurs. Females lack a left oviduct.
Leptotyphlopids eat soft-bodied invertebrates, and secretions that fool termites allow them to take up residence in termite nests and eat eggs and larvae. Leptotyphlopids have also been found in screech owl nests consuming arthropods -- the Texas blindsnake Leptotyphlops dulci is often brought to the nest as a prey item by these owls, although the snakes sometimes escape. Nests with these resident blindsnakes enjoy a lower chick mortality rate, presumably because the snakes are eating parasitic arthropods. The feeding mechanism of Leptotyphlops (mandibular raking) has been well characterized.
Leptotyphlopids are oviparous, laying up to 13 eggs per clutch. Female snakes have been observed coiled around their eggs, possibly demonstrating parental care.
Leptotyphlopidae is generally considered to be sister to the clade of Typhlopidae and Anomalepididae, although a recent analysis of molecular data strongly supports them as sister to Typhlopidae. Some morphological evidence, such as characteristics of the tongue, also support their sister relationship to Typhlopidae. Other authors have also questioned the monophyly of Scolecophidia, based on other morphological data.
Walter Rose, quoted in Greene (1997):
From one point of view all living snakes may be regarded as degenerate quadrupeds, but some have gone further in having the appearance if not actuality of degenerated degenerates! No reptile approaches so nearly the stage of being 'sans teeth, sans eyes, sans taste, sans everything' as the members of the Typhlops and Leptotyphlops genera.
Greene, H. 1997. Snakes: The evolution of mystery in nature. University of California Press, Berkeley.
Heise, P. J., L. R. Maxson, H. G. Dowling, and S. B. Hedges. 1995. Higher-level snake phylogenies inferred from mitochondrial DNA sequences and 12s rRNA and 16s rRNA genes. Mol. Biol. Evol. 12: 259-265.
Kley, N. http://www.bio.umass.edu/biology/brainerd/kley.html. Includes videos of Leptotyphlops feeding.
Kley, N. J. and E. L. Brainerd. 1999. Feeding by mandibular raking in a snake. Nature 402: 369-370.
List, J. C. 1955. External limb vestiges in Leptotyphlops. Herpetologica 11: 15-16.
McDowell, S. B. 1972. The evolution of the tongue of snakes, and its bearing on snake origins. in Evolutionary Biology (T. Dobzhansky, M, Hecht, and W. Steere, eds) 6: 191-273. Appleton-Century-Crofts, New York.
Rieppel, O. 1988. A review of the origin of snakes. Evol. Biol. 22: 37-130.
Zug, G. 1993. Herpetology: An introductory biology of amphibians and reptiles. Academic Press, San Diego
Contributors
Jennifer C. Ast (author).