Description of the mature larva of four species of the Australasian endemic genus Sternopriscus Sharp, 1882 (Coleoptera: Dytiscidae) with phylogenetic considerations

Abstract

The instar III larvae of the Australian endemic species Sternopriscus alpinus Hendrich and Watts, 2004, S. clavatus Sharp, 1882, S. hansardii (Clark, 1862) and S. multimaculatus (Clark, 1862) are described and illustrated for the first time. We explore implications for understanding the evolution of larval morphological traits amongst selected Sternopriscina genera. A parsimony analysis based on 84 larval characteristics of 11 species in six genera was conducted using the program TNT. Larvae of Sternopriscus Sharp, 1882 are characterised by the last abdominal segment not extending into siphon and by very elongate urogomphi. Sternopriscus is subdivided into two groups based either on absence or reduction in number of natatory setae along the dorsal margin of femora, tibiae and tarsi. Sternopriscus is postulated to be sister to a clade comprised of Chostonectes Sharp, 1882, Megaporus Brinck, 1943 and Antiporus Sharp, 1882.