Larval morphology of Yola Gozis, 1886 (Coleoptera: Dytiscidae: Bidessini) and comparison with other genera of the tribe Bidessini

Abstract

The second and third instars of Yola wraniki Wewalka, 2004 are described and illustrated for the first time, with detailed morphometric and chaetotaxic analyses of the cephalic capsule, head appendages, legs, last abdominal segment, and urogomphi. The mature larva of Yola Gozis, 1886 can be distinguished from those of the other known Bidessini genera by the following combination of morphometric and chaetotaxic characters: ratio length of metathoracic leg/head width greater than 2.85; ratio length of urogomphus/head width greater than 2.70; absence of a ventroapical spinula on third antennomere; secondary temporal spine-like setae on parietale; natatory setae on tibia; secondary posteroventral setae on tarsus and secondary setae on urogomphus; presence of pore PAk and secondary dorsal setae on protarsus; and mandibular pore MNa located in a clearly distal position with respect to pore MNb. A key for the identification of the third instars of the genera of Bidessini known in detail is provided.