Strepsiptera - Classification

Classification

The order, named by William Kirby in 1813, is named for the hind wings (strepsi = twisted, ptera = wing), which are held at a twisted angle when at rest. The forewings are reduced to halteres (and initially were thought to be dried and twisted).

Strepsiptera are an enigma to taxonomists. Originally, they were believed to be the sister group to the beetle families Meloidae and Ripiphoridae, which have similar parasitic development and forewing reduction; early molecular research suggested their inclusion as a sister group to the flies, in a clade called the halteria, which have one pair of the wings modified into halteres, and failed to support their relationship to the beetles. More recent molecular studies, however, suggest they are outside the clade Mecopterida (containing the Diptera and Lepidoptera), yet there is no strong evidence for affinity with any other extant group. Study of their evolutionary position has been problematic due to difficulties in phylogenetic analysis arising from long branch attraction. The most basal strepsipteran is the fossil Protoxenos janzeni discovered in Baltic amber, while the most basal living strepsipteran is Bahiaxenos relictus, the sole member of the family Bahiaxenidae. The earliest known strepsipteran fossil is that of Cretostylops engeli, discovered in middle Cretaceous amber from Myanmar.

A molecular study strongly suggests the closest relations to this order are the Coleoptera (beetles).