Hydraena (Hydraenopsis) spiralis, Perkins, 2023

Perkins, Philip D., 2023, New Neotropical and Nearctic species of water beetles in the genera Hydraena Kugelann and Ochthebius Leach, a key to North American genera and subgenera of the family, new distribution records, and a synopsis of ecology, behavior and morphology related to aquatic life (Coleoptera: Hydraenidae), Zootaxa 5367 (1), pp. 1-86 : 27-29

Hydraena (Hydraenopsis) spiralis , new species

Figs. 1 (habitus comparison), 15 (habitus and aedeagus)

Type Material. Holotype (male): “ MEXICO: Guanajuato, Victoria, Pto de Palmas , 1950 m, 11.viii.1999, 21°24’59’’N, 100°04’60’’W, 1462 m, R. Arce col.” ( IEXA) . Paratype: Same data as holotype (1 IEXA) .

Differential Diagnosis. This new species is a member of the H. argutipes Subgroup of the H. leechi Group; the subgroup is previously known from nine species (see Perkins 1980: 37, 151). Based on the aedeagal morphology ( Fig. 15 ), this species is clearly related to H. prieto Perkins 1980 . Externally, differences between the two species include the much shallower (or absent) pronotal foveae and the much wider and less widely separated metaventral plaques of H. spiralis n. sp. Reliable determinations in the H. argutipes Subgroup will include dissection of males.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.51/0.67; head width 0.37; pronotum 0.37/0.53, PA 0.42, PB 0.45; elytra 0.89/0.67. Habitus as illustrated ( Fig. 15 ). Dorsum dark brown, palpi testaceous, tip of last palpomere not darker. Dorsum of head and pronotum moderately finely moderately sparsely punctulate, interstices shining; punctures of frons disc ca. 1xef, pronotal punctures ca. twice as large, interstices ca. 1–2xpd or slightly larger; punctures of clypeus very fine, lateral areas microreticulae. Labrum apicomedially deeply excised. Pronotum with anterior margin weakly emarginate over middle 1/2; anterolateral pronotal fovea shallow, other usual foveae absent.

Elytra with summit of posterior declivity at about midlength; lateral explanate margins moderately wide; on basal 1/3 punctures ca. 1xpd of largest pronotal punctures, punctures becoming gradually smaller toward posterior. Intervals not raised, width ca. 1–2xpd or slightly greater, as are interstices between punctures of a row. Apices in dorsal aspect conjointly rounded, in posterior aspect margins forming very shallow angle with one another.

Venter: Mentum and postmentum very finely very densely punctulate, dull. Genae raised, shining, without posterior ridge. Ratios of P2 width and plaque shape (P2/w/l/s) ca. 2/1/4/4. P1 laminate; median carina sinuate in profile. P2 rather wide, l/w ca. 2/1, sides slightly converging toward blunt apex, apex raised slightly above mesoventral intercoxal process. Plaques moderately large, widest posteriorly, tapering to point anteriorly, straight, medial margins parallel, not raised, located at sides of deep median depression. AIS width at straight posterior margin ca. 1.5x P2. Protibia very slightly arcuate, slightly widenend in distal 1/2. Meso- and metatibiae slender, straight. Abdominal apex symmetrical; last tergite with small, shallow apicomedian indentation.

Distribution. Currently known only from the type locality.

Etymology. Named in reference to the spiral shape of the aedeagal flagellum.

Figures

FIGURE 1. Dorsal habitus of Hydraena species.

FIGURE 15. Hydraena (Hydraenopsis) spiralis new species, holotype habitus and aedeagus.