Evolution and systematics

The phylogenetic position of Typhlopidae within the order Squamata has been enigmatic and controversial for more than two centuries. Most early taxonomists grouped ty-phlopids together with various forms of snake-like lizards, such as amphisbaenians, burrowing skinks, and limbless an-guids. This practice continued throughout the early nineteenth century until the publication of the sixth volume of Duméril and Bibron's monumental work, "Erpétologie Général ou Histoire Naturelle Complète des Reptiles" in 1844. Based on extensive anatomical comparisons with other squamates, Duméril and Bibron grouped typhlopids together with leptotyphlopids (to the exclusion of superficially similar limbless lizards) into "Scolécophides," one of five major "sections" that they recognized within Serpentes. This classification scheme soon gained widespread acceptance, and the Latinized name Scolecophidia was introduced in 1864 by Edward Drinker Cope.

Most recent workers have at least tentatively accepted the hypothesis that Scolecophidia represents a natural (mono-phyletic) group. However, this notion has not gone unchallenged. Several morphological and molecular studies have concluded that Scolecophidia may be polyphyletic, including two influential anatomical studies that suggested that Ty-phlopidae may be placed improperly within Serpentes (i.e., that typhlopids represent a divergent lineage of limbless lizards). Nevertheless, most cladistic analyses of squamate interrelationships have supported the hypothesis of scole-cophidian monophyly. Moreover, the majority of such studies have suggested that within Scolecophidia, Typhlopidae is more closely related to Anomalepididae (early blindsnakes) than to Leptotyphlopidae (slender blindsnakes).

The fossil record for Typhlopidae is extremely poor. Only two fossil taxa have been described. Typhlops grivensis is known from three trunk vertebrae found in Middle Miocene deposits in France, and T. cariei is known from seven trunk vertebrae discovered in Subrecent deposits on Mauritius. Given that these species were described solely on the basis of vertebral morphology, their placement in the genus Typhlops must be considered tentative. Unidentified scolecophidian fossils have also been found in Tertiary deposits in Europe, Africa, Australia, and South America, and it is likely that many of these fragmentary fossils represent typhlopid remains. Unfortunately, the very incomplete scolecophidian fossils that have been unearthed thus far have shed little light on the evolution of blindsnakes. However, some of these fossil remains have improved our understanding of the biogeographical history of blindsnakes.

No subfamilies are recognized.

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