Revision of the Siphonapteran genus Stephanocircus Skuse, 1893, (Stephanocircidae)

Abstract

The Siphonapteran genus Stephanocircus Skuse, 1893, comprising the known helmet-fleas of Australia, is reviewed. S. jarvisi Rothschild, 1908, is placed in a new genus, Coronapsylla. Three new species and a new subspecies of Stephanocircus are described in detail. Of these, S. harrisoni, sp. nov., is immediately recognizable by virtue of the very flat anterior margin of the helmet, and S. domrowi, sp. nov., is distinctive in Stephanocircus s. str. in having eight or nine spines in the genal comb, instead of the maximum of seven seen in S. greeni, sp. nov., and S. pectinipes Rothschild, 1915. The presence of false combs of spiniform bristles on the protibia of the last-named readily separates it from S. greeni. S. greeni tasmanica, subsp. nov., is distinguishable from the nominate Victorian form in possessing unusually long spines in the 'minor combs' on the abdomen. A key to the known Stephanocircus s. str. is included, and all the species are fully diagnosed and illustrated, as is Coronapsylla jarvisi, comb. nov. The three new species and S. dasyuri Skuse, 1893, infest marsupials, as does C. jarvisi, while S. concinnus Rothschild, 1916, and S. pectinipes are apparently rat-fleas. S. simsoni Rothschild, 1905, has been found on a variety of murids and marsupials.

The spines of the combs of the peramelid-infesting Stephanocircus are sharply pointed, in contrast to those of the helmet-fleas of rats. These and other distinctions are believed to be adaptive and constitute examples of convergent evolution. The relationship between the subfamily Stephanocircinae (which includes only the above two genera) and the South American subfamily, the Craneopsyllinae, is discussed.