Evolution and systematics

The family Anomalepididae was first established in 1939 by Edward H. Taylor after he discovered that snakes of the genus Anomalepis exhibit patterns of dentition and scalation that are significantly different from those seen in other blind-snakes. Soon thereafter, anatomical studies revealed that Helminthophis, Liotyphlops, and Typhlophis share many distinctive morphological features with Anomalepis, indicating that these three genera also belong in the family Anomalepididae.

Although morphological evidence strongly suggests that Anomalepididae represents a natural, or monophyletic, group, the interrelationships among the four genera of early blind-snakes and their phylogenetic affinities within Serpentes remain poorly understood. Most recent snake systematists have placed Anomalepididae together with the families Leptoty-phlopidae (slender blindsnakes) and Typhlopidae (blindsnakes) in the infraorder Scolecophidia. However, the interrelationships of these three families have been controversial. In general, characters relating to cranial morphology, visceral topography, and scalation patterns suggest that, within Scole-cophidia, Anomalepididae is most closely related to Typhlop-idae. In contrast, characters associated with the morphology of the hyobranchial apparatus support a close relationship between Leptotyphlopidae and Typhlopidae. Adding further confusion to this issue, a small number of morphological and molecular phylogenetic analyses have concluded that Scole-cophidia may be polyphyletic (i.e., that the three families of blindsnakes may not share a close common ancestry).

Unfortunately, the fossil record has offered few clues to help resolve this confusion. No fossils have been discovered yet that can be assigned unequivocally to Anomalepididae (although Suffusio predatrix, from the Paleocene of Texas, has been identified tentatively as an anomalepidid), and the few leptotyphlopid and typhlopid fossils that have been described are known only from very incomplete remains (usually isolated vertebrae). Thus, the evolutionary origin of early blindsnakes and their relationships to other blindsnakes remain enigmatic.

No subfamilies are recognized.

Was this article helpful?

0 0

Post a comment