On the affinities of the burrowing asps Atractaspis (Serpentes: Atractaspididae)

An analysis is presented of a sample of Atractaspididae (sensu McDowell) plus Macrelaps, Aparallactus, Apostolepis, Elapomorphus, Homoroselaps and six genera of African elapids in respect of squamation, reproductive organs, skull, head muscles and vertebrae. Homoroselaps is linked with the African Elapidae and is returned to that family. Scattered special resemblances to atractaspids are interpreted as homoplasies. Some interrelationships of the African elapids are suggested. The South American Apostolepis and Elapomorphus represent a separate, possibly related, lineage at the same grade level as the African Atractaspididae. Macrelaps and Aparallactus are transferred to the Atractaspididae. Atractaspis emerges as a low grade but highly divergent member of the family. Macrelaps is the most primitive. The other taxonomic units are completely resolved with, however, the anomaly of reversal to the seemingly primitive states of six characters in four lineages (six genera). The Atractaspididae, Apostolepis and Elapomorphus are regarded as low grade members of the Caenophidia. It is suggested that early in the history of the caenophidian lineage a venom apparatus was acquired, prior to the major radiation of the group. Many descendent lineages show regression of the venom apparatus.