Berosini

Minoshima, Yûsuke N. & Hayashi, Masakazu, 2015, Description of the larval stages of the berosine genera Berosus and Regimbartia based on the Japanese species B. japonicus and R. attenuata (Coleoptera: Hydrophilidae), Acta Entomologica Musei Nationalis Pragae 55 (1), pp. 47-83 : 51

Key to the genera of the larvae of the tribe Berosini

Larvae of the Berosini are distinguishable from other hydrophilid larvae by the presence of one inner projection or seta on antennomere 1, which is an autapomorphy of the Berosini .

In the following key, we used our data concerning Berosus and Regimbartia and combined them with those of the previous authors (see Table 1) for the morphology of the remaining three berosine genera and for the intrageneric variation of Berosus . ARCHANGELSKY (2008) provided a table comparing larval morphology of all five genera.

1 Abdomen with tracheal gills. .................................................... Berosus Leach, 1817

– Abdomen without tracheal gills. ............................................................................. 2

2 Clypeolabrum strongly asymmetrical; left epistomal lobe strongly projecting anteriorly, bearing a series of stout setae ( Figs 3A , 5B ); mandibles strongly asymmetrical ( Figs 4C–D , 7A–B ); abdomen without setiferous projections; spiracular atrium reduced. ....................................................................................... Hemiosus Sharp, 1882

– Clypeolabrum almost symmetrical ( Figs 9C , 13C ); epistomal lobe not strongly projecting anteriorly; mandibles symmetrical to slightly asymmetrical ( Figs 11A–B , 15A–B ); labium with ligula ( Figs 11C–D , 15C–D ); abdomen with setiferous projections ( Fig. 8A–B, D ); spiracular atrium well developed ( Fig. 12C ). .......................... 3

3 Antennomere 1 not widened distally. ...................................... Derallus Sharp, 1882

– Antennomere 1 widened distally ( Figs 10A , 14A ). ................................................. 4

4 Inner projection of antennomere 1 pointed apically, spine-like; apex of antennomere 2 with inner extension. .................................................. Allocotocerus Kraatz, 1883

– Inner projection of antennomere 1 rounded apically ( Figs 10A , 14A ); apex of antennomere 2 without inner extension. .................................. Regimbartia Zaitzev, 1908

Figures

Fig. 3. First instar larva of Berosus (Berosus) japonicus Sharp, 1873, anterior margin of head capsule, dorsal (A) and ventral (B) (both drawn from dorsal).

Fig. 5. Third instar larva of Berosus (Berosus) japonicus Sharp, 1873, dorsal; A – head capsule; B – anterior margin of head capsule; C – detail of setae of gFR2; D – spiracular atrium; E – spiracle in spiracular atrium.

Fig. 4. First instar larva of Berosus (Berosus) japonicus Sharp, 1873, head appendages. A–B – antenna, dorsal (A) and ventral (B); C–D – left and right mandible, dorsal; E–F – maxilla, dorsal (E) and ventral (F); G–H – labium, dorsal (G) and ventral (H).

Fig. 7. Third instar larva of Berosus (Berosus) japonicus Sharp, 1873, head appendages. A–B – mandible, dorsal; C–D – labium, dorsal (C) and ventral (D).

Fig. 9. First instar larva of Regimbartia attenuata (Fabricius, 1801), head capsule. A–B – head capsule, dorsal (A) and ventral (B); C – anterior margin of head capsule, dorsal; D–E – variation of sensilla PA15–18, ventral.

Fig. 13. Third instar larva of Regimbartia attenuata (Fabricius, 1801), head capsule.A–B – head capsule, dorsal (A) and ventral (B); C – anterior margin of head capsule, dorsal.

Fig. 11. First instar larva of Regimbartia attenuata (Fabricius, 1801), head appendages. A–B – mandible, dorsal; C–D – labium, dorsal (C) and ventral (D).

Fig. 15. Third instar larva of Regimbartia attenuata (Fabricius, 1801), head appendages. A–B – mandible, dorsal; C–D – labium, dorsal (C) and ventral (D).

Fig. 8. Third instar larva of Regimbartia attenuata (Fabricius, 1801). A–B – habitus, dorsal (A) and ventral (B); C – cuticular projection on pronotum, dorsal; D – lateral setiferous projection, dorsal; E – cuticular projections on abdominal segment, dorsal.

Fig. 12. Third instar larva of Regimbartia attenuata (Fabricius, 1801). A – head, dorsal; B – prosternal sclerite, ventral; C – spiracular atrium, dorsal.

Fig. 10. First instar larva of Regimbartia attenuata (Fabricius, 1801), head appendages. A–B – antenna, dorsal (A) and ventral (B); C–D – maxilla, dorsal (C) and ventral (D).

Fig. 14. Third instar larva of Regimbartia attenuata (Fabricius, 1801), head appendages. A–B – antenna, dorsal (A) and ventral (B); C–D – maxilla, dorsal (C) and ventral (D).