Meropathina, Perkins, 1997

Perkins, Philip D., 2018, A new genus and new species of Meropathina from Lord Howe Island (Coleoptera: Hydraenidae), Zootaxa 4444 (4), pp. 409-420 : 413-415

Subtribe Meropathina Perkins

Perkins 1997: 143.

The many morphological differences betWeen the genera of Meropathina are discussed and illustrated by Perkins (1997, 2004). Some of these differences are summarized beloW and presented in the key to genera that folloWs.

Recent unpublished DNA sequence data (I. Ribera, pers. com.) has corroborated the sister group relationships of the Ochthebiina and Meropathina , Which Were proposed by Perkins (1997) on the basis of the hypomeral antennal pocket morphology, and differences in the exocrine secretion delivery systems, among other morphological characters.

The antennal club of all members of Meropathina have sensilla interspersed With the hydrofuge setae. These sensilla are usually located near the distal end of the club articles. In members of Meropathus ( Fig. 12 ) and Tympanogaster they are not organized into groups, Whereas in Tympallopatrum the sensilla form distinct clusters ( Figs. 15, 16 ). The antennae of Prototympanogaster are similar to those of Tympanogaster .

The maxilla in members of Tympanogaster provide distinctive, derived features ( Figs. 25–28 ). The lacinia has a large, scoop-like, apical tooth in Tympanogaster ; in the presumed ancestral condition of the Ochthebiini this structure has a tooth-like shape With a bifid apex (see Perkins 1980: 297). The galea has several closely spaced, flat teeth that together form a palmate shape; this is unique in the family. There is some variation in the length and proportions of the maxillary palpi. This variation, like the variation in leg length, is related to the microhabitat: the strictly aquatic members having longer legs and palpi, and the moss dWelling or humicolous species having shorter legs and palpi. The maxillae of Prototympanogaster ( Fig. 21 ) are similar in morphology to that of Tympanogaster , and the legs are moderately long.

The mentum of Prototympanogaster lordhowensis and Meropathus chuni are different in shape and especially chaetotaxy ( Figs. 21, 22 ).

Figures

FIGURES 10–13. Comparison of the hypomeron, antennal pocket, and posterior border of eye: (10–11) Tympanogaster (s. str.) modulatrix (with anomalous second pair of hypomeral antennal pocket setae), (12–13) Meropathus campbellensis. Structures: (e) periocular exocrine pores, (g) hypomeral antennal pocket setae (h) hydrofuge hypomeron, (i) hypomeral antennal pocket, (k) cupule article of antenna, (n) prosternum, (t) postocular hydrofuge, (V) cerVical sclerite.

FIGURES 14–19. Tympallopatrum longitudum: (14) dorsal habitus, (15–16) antenna and prothoracic hypomeron, (17) Venter of head, (18–19) Venter of head, mentum and labrum.

FIGURES 23–28. Maxillae of representatiVe members of Meropathina

FIGURES 21–22. Comparison of maxilla and mentum: (21) Prototympanogaster lordhowensis, (22) Meropathus chuni.