Larval Morphology ofYolaGozis, 1886 (Coleoptera: Dytiscidae: Bidessini) and Comparison with other Genera of the Tribe Bidessini

Larvae of Huxelhydrus syntheticus Sharp, 1882 (Coleoptera: Dytiscidae: Bidessini)

“…Finally, the presence of secondary setae on the urogomphi separates Huxelhydrus from Anodocheilus, Glareadessus, Hydroglyphus, Hypodessus, Liodessus and yola. Third instars of Huxelhydrus key to Allodessus Guignot, 1953+ Limbodessus Guignot, 1939 in the key to Bidessini larvae provided by Michat et al (2015). Huxelhydrus can be distinguished from these two genera in the relative position of the mandibular pores MNa and MNb, as mentioned above.…”

“…A summary of characters useful to separate third-instar larvae of several Bidessini genera was presented by Michat et al (2015). Based on this information, mature larvae of Huxelhydrus can be separated from those of all other genera by the combination of the following two characters: mandibular pore MNa located in a clearly distal position with respect to pore MNb, and presence of secondary dorsal setae on protarsus.…”

“…The generic composition of Bidessini, however, has changed significantly over the years, presently representing one of the most significant radiations of diving beetles with almost 50 genera and more than 700 species (Nilsson & Hájek 2018). Larvae of this tribe, however, are far less known than adults, with less than 15 genera described in detail (see Michat et al 2015 for a review). Larval chaetotaxy is a significant source of characters both for diagnosis of genera and species and for phylogenetic analyses (e.g.…”

“…The only mention in the literature is a drawing of the last abdominal segment and urogomphus in the context of a key to larvae of New Zealand diving beetles (Winterbourn et al 2006). Therefore, the recent discovery of all larval instars of Huxelhydrus syntheticus Sharp, 1882 allows us to provide, for the first time, a detailed description of this genus in the context of modern works on Bidessini larvae, which incorporate detailed morphometric and chaetotaxic analyses (Alarie & Wewalka 2001;Michat & Alarie 2006, 2008Michat & Torres 2006, 2013Michat et al 2010Michat et al , 2011Michat et al , 2012Michat et al , 2015). We also discuss the most relevant characters to separate Huxelhydrus from the other Bidessini genera for which the larvae have been described in detail.…”