Menomadraena, Perkins, 2017

Perkins, Philip D., 2017, Hydraenidae of Madagascar (Insecta: Coleoptera), Zootaxa 4342 (1), pp. 1-264 : 170-171

Menomadraena , new genus

Type species. Menomadraena nitedula , new species.

Diagnosis. Recognized by the combination of the following characters: 11 articles of the antenna (six + club), terminal article larger than preterminal ( Fig. 220 ); the very short maxillary palpi, which are much shorter than the antennae, and are held beneath the laterally and anteriorly wide clypeus(e.g., Figs. 162–163); the large, circular, flat, dense tubercles of the pronotum; the very deep postocular emarginations of the pronotum; the elytra with a sutural costa plus three strong costae, the median of which is arcuate posteriorly and attains the elytral margin; the elytra with three rows of punctures between the costae, the mesoventral intercoxal process with small tubercle; and the non-hydrofuge metaventrite and abdominal ventrites. Refer to the key to genera of Madagastrini for comparisons with other genera.

Description and notes. For details of morphological characters, see below under descriptions of the six species. In addition to the characters noted above, all six species have very prominent ocelli, the labrum is hidden in dorsal view by the overhanging clypeus, and the intercostal areas of the elytra have three rows of punctures (although sometimes with four rows for a short space very near the base). The elytral punctures each have a small seta and a small granule on each side, the size of which varies slightly in the species. The species are quite similar to one another, and there are no evident sexual dimorphisms; dissections to examine male genitalia are necessary for reliable determinations.

Etymology. "Meno" (strength, force), and "mad" from Madagascar, and "draena" from Hydraena . Members of the genus have a thick, strong cuticle; Gender feminine.

Habitats. Members of Menomadraena have only been collected by "sifting litter (leaf mold, rotten wood)" and are clearly non-aquatic, which explains the lack of hydrofuge pubescence. Nearly all specimens were collected by Brian L. Fisher, whose focus was collecting ants, the presence of which may explain what could be considered protective morphology of the adults: hard, thick cuticle; very short maxillary palpi hidden beneath the overhanging clypeus; and short tarsi. The rather long antennae would be vulnerable to attack, which may explain why the postocular emarginations are so deep: to allow rapid withdrawal of the antennal club into the protective antennal pockets on the anterior face of the prothorax. Specimens of Menomadraena have been collected at an elevation range of 800–1990 m.

Figures

FIGURES 219 – 223. Antennae, maxillary palpi, and spermathecae.