Homalotini, Heer, 1839

Ashe, James S., 2005, Three new genera and four new species of aleocharine staphylinids with unusually long mandibles from Australia (Coleoptera: Staphylinidae: Aleocharinae: Homalotini), Zootaxa 1002 (1), pp. 21-44 : 33

Key for identification of the known Australian genera of Homalotini with unusually long slender mandibles

The members of this group are easily recognized by the combination of 4­4­5 tarsal segmentation, and the very long slender mandibles that cross in the front of the head and whose apices extend virtually to, or beyond, lateral margins of the head. Unfortunately, the features which reliably distinguish the genera are only easily seen by examination of dissected specimens with compound optics.

1. Ligula elongate and entire at apex ( Fig. 8 ) ............................................ Eumecognathus

– Ligula divided into 2 pointed lobes ( Figs. 18 , 29 ) ...................................................... 2

2. Ligula divided to near base into 2 widely separated pointed lobes ( Fig. 18 ); prementum with 2 discal setae, bases of discal setae widely separated; medial pseudopore field of prementum wide with numerous pseudopores; pair of antero­lateral setae of the labrum greatly elongated and whip­like ( Fig. 14 ); clypeal setae not elongated and whip­like; base on mandibles not modified ( Fig. 16 ) .................................. Siagotanyx

– Ligula divided to near midpoint into 2 narrowly separated pointed lobes ( Fig. 29 ); prementum with 1 discal seta; medial pseudopore field of prementum narrow with few pseudopores ( Fig. 29 ); antero­lateral setae of the labrum not greatly elongated or whip­like ( Fig. 25 ); clypeal seta on each side of midline greatly elongated and whiplike; base of mandibles slightly to greatly modified into triangular blade­like projections ( Fig. 27 ) ........................................................................................ Drepanomastax

Figures

FIGURES 4–8. Eumecognathus tasmaniensis Ashe. 4, labrum, dorsal aspect. 5, epipharynx. 6, right and left mandibles respectively, ventral aspect. 7, left maxilla, ventral aspect. 8, labium, ventral aspect. Scale bar = 0.1 mm.

FIGURES 14–18. Siagotanyx rufa Ashe. 14, labrum, dorsal aspect. 15, epipharynx. 16, right and left mandibles respectively, ventral aspect. 17, right maxilla, ventral aspect. 18, labium, ventral aspect. Scale bar = 0.1 mm.

FIGURES 25–29. Drepanomastax splendida Ashe. 25, labrum, dorsal aspect. 26, epipharynx. 27, right and left mandibles respectively, ventral aspect. 28, left maxilla, ventral aspect. 29, labium, ventral aspect. Scale bar = 0.1 mm.