Parhydraena Orchymont, 1937

Perkins, Philip D., 2009, Revisions of the genera Parhydraena Orchymont, Protozantaena Perkins, Decarthrocerus Orchymont, and Parhydraenopsis nomen novum, aquatic and humicolous beetles from Africa and Madagascar, and comparative morphology of the tribe Parhydraenini (Coleoptera: Hydraenidae), Zootaxa 2038, pp. 1-119 : 14

Parhydraena Orchymont, 1937

Parhydraena Orchymont 1937: 457 (type species Hydraena brevipalpis Régimbart , by original designation).

Diagnosis. Distinguished from Protozantaena , Discozantaena ,and Parhydraenopsis by the presence of an hypomeral carina (e.g., Figs. 2, 3). Additionally distinguished from Protozantaena by the much larger size and the markedly different aedeagus, from Discozantaena by the markedly different habitus ( Fig. 1), the hypomeral antennal pocket setae, and the markedly different aedeagus. Distinguished from Decarthrocerus by the markedly different habitus, the smaller antennal pocket with differently placed and differently shaped hypomeral pocket setae, and the markedly different aedeagus. Recognized by the moderate size (length ca. 1.64–2.17 mm); the non-cordiform pronotum; the (in some species) elongate maxillary palpi; the elytral serial punctures more prominent than the punctures of the intervals; the ten-articled antenna (five + club); the hypomeral carina; and the hypomeral antennal pocket setae forming a contiguous line at the margin of the antennal pocket.

Description. Body size moderate, length ca. 1.64–2.17 mm; body form variable, elongate oval to more broadly oval, weakly to moderately transversely convex dorsally, head not deflexed. Antennomeres ten (five + club), second equal to or slightly shorter than combined lengths of third to fifth. Maxillary palpus length very variable, length/head width ratio ca. 0.44–0.91; ratios of articles two to four (last) variable, but fourth always longest and third always shortest (e.g., from ca. 5/2/8 to ca. 12/7/15). Eyes well-developed, not elevated, in dorsal aspect 7–11 facets in longest series. Labrum approximately continuing slope of clypeus, usually same length or slightly longer than clypeus, shape of anterior margin straight to emarginate. Clypeus anterior margin and frontoclypeal suture slightly arcuate. Ocelli weakly convex, located midway between midline and eyes. Frons very weakly convex between ocelli; area behind and between ocelli lacking carinae. Pronotum with anterior and posterior transverse impressions on disc, varying in depth, posterior impression usually Ushaped; anterior hyaline border present over ca. median third, extremely narrow. Hypomeron with welldeveloped carina at margin of hydrofuge pubescence; antennal pocket bordered posteriorly and partially laterally by contiguous, arcuate setae forming cup, ca. 8–14 total. Proventral antennal cleaner, a dense cluster of sharp spines, located on anterolateral margin of each side of proventrite. Metaventrite with shallow impression on disc in basal 1/2, with midlongitudinal carina between impression and mesoventral intercoxal process. Elytra with ten rows of punctures, six between suture and humerus; serial punctures deeper and larger than punctures on intervals, setae slender and usually very short. Intercoxal sternite small, triangular. Aedeagus with complicated distal piece fused to main-piece, gonopore at tip of short tube-like process; parameres well-developed, multisetose at tips.