Larval morphology of Agabinae (Coleoptera: Dytiscidae): Descriptions of three species of the subgenus Agabus s. str. Leach, 1817 with phylogenetic considerations

Abstract

The larvae of three species of Agabus s. str. Leach, 1817, A. bifarius (Kirby, 1837), instar III, A. disintegratus (Crotch, 1873), instars I–III, and A. falli (Zimmermann, 1934), instars I–III, are described including for the first time a detailed chaetotaxy analysis of the cephalic capsule, head appendages, legs, last abdominal segment and urogomphi. Larvae of A. falli show several unique morphological features that differentiate them from those of the other species of Agabini studied. A provisional parsimony analysis based on 55 larval characteristics of 17 species in seven genera of the subfamily Agabinae was conducted using the program TNT. As a result of this analysis, Agabini was recovered as polyphyletic while Platynectini and Hydrotrupini are deemed monophyletic.