Larval description and chaetotaxic analysis of Gyrinus monrosi MOUCHAMPS, 1957 (Coleoptera: Gyrinidae)

MICHAT, M. C., M. ARCHANGELSKY & L. FERNÁNDEZ

Koleopterologische Rundschau

The Viena Coleopterists Society

Lugar: Viena; Año: 2010 vol. 80 p. 1 - 14

0075-6547

The three larval instars of the Neotropical Gyrinus (Oreogyrinus) monrosi MOUCHAMPS, 1957 (Coleoptera: Gyrinidae) are described and illustrated for the first time including detailed morphometric and chaetotaxic analyses of the cephalic capsule, head appendages and legs. Larvae of Gyrinus MÜLLER, 1764 are diagnosed by the following combination of characters: cephalic capsule not constricted at level of occipital region; medial lobe of frontoclypeus with four inconspicuous teeth; presence of a mandibular retinaculum; lacinia broad, indented apically; claws with basoventral spinulae. Larvae of the subgenus Oreogyrinus OCHS, 1935 have the medial hooks of the abdominal segment X slightly longer than the lateral hooks, whereas in the subgenus Neogyrinus HATCH, 1925 the medial hooks are much shorter than the lateral ones. Regarding chaetotaxy, Gyrinus differs from Andogyrus OCHS, 1924 and Dineutus MACLEAY, 1828 in the absence of additional setae on the mandible, the distal position of pore MXg and the presence of seta TR2, from Orectochilus LACORDAIRE, 1835 in the shape of the pretarsal setae PT1 and PT2, and from all other gyrinid genera with known larvae except Aulonogyrus MOTSCHULSKY, 1853 in the presence of a row of robust hooklike additional setae on the dorsointernal margin of the stipes.