![]() ![]() Most occupy terrestrial habitats in moist tropical forests, and some are known to prey on amphibians. ![]() Little is known of the biology of these strange colubrids, many of which have unusual, protuberant scales on the body or head. The Xenodermatinae is a small group of six genera and about 15 species from southern and eastern Asia. That said, several subfamilies of Colubridae are widely recognized, if not universally accepted. That is, some colubrids may be more closely related to members of one of those families than they are to certain other colubrids. Furthermore, the relationship between colubrids and two other colubroid families, the Elapidae and Atractaspididae, is unclear, and it is possible that the Colubridae itself is paraphyletic relative to one or both of those families. However, even when well-defined clusters of genera are confirmed, the relationships among those clusters often remain unclear, and widely accepted phylogenetic hypotheses concerning colubrid relationships have remained elusive. The application of both phylogenetic systematic (cladistic) and molecular methods has helped to clarify the relationships within many groups of colubrid snakes. In some cases these features yielded groupings that have stood the test of time, but in many instances the failure to distinguish between ancestral and derived conditions resulted in unnatural groups. Early classifications were based largely upon similarities in scale characteristics, dentition, and the form of the hemipenes (the paired copulatory organs of male squamates). The relationships among genera of colubrids remain poorly understood and highly controversial, despite numerous attempts to bring order to this complex group. However, our knowledge of fossil snake faunas is drawn primarily from temperate remains, so inferences for tropical regions should be drawn with caution. However, the group seems to have radiated rapidly during the Miocene (5–25 million years ago), and by the end of that period a fauna previously dominated by boa-like species had largely been replaced by colubrids, elapids, and viperids. Although some colubrids are generalists, many exhibit strong specialization for a particular environment and/or specific prey.įossils attributed to the Colubridae first appear in the Lower Oligocene, about 35 million years ago. Indeed, it is the ability of colubrids to adapt to widely different habitats, diets, and life history modes that above all characterizes this extraordinary lineage. For that reason, few useful generalizations apply to this expansive family. The Colubridae comprise by far the largest and most diverse family of snakes, containing about 70% of all snake species. Habitat The family includes terrestrial, fossorial, arboreal, and aquatic speciesĬonservation status Extinct: 1 species Critically Endangered: 6 species Endangered: 7 species Vulnerable: 8 species Lower Risk/Near Threatened: 4 species Data Deficient: 10 speciesĭistribution Worldwide except Antarctica, extremely high latitudes of Eurasia and North America, and central and western Australia Evolution and systematics Number of genera, species Approximately 300 genera approximately 1,700 species Thumbnail description Highly variable in size, body form, and color pattern ranges from short, stout, drab species to large, slender, boldly marked forms ![]()
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