Hydraena (Hydraenopsis) belicollis, 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 : 12-15

Hydraena (Hydraenopsis) belicollis , new species

Figs. 2 (habitus comparison), 6 (habitus and aedeagus)

Type Material. Holotype (male): “ BELIZE: 16°29’35’’N 89°2’49’’W Cayo District, Chiquibul N. P., Doyle’s Delight, nr. Campground , 1100 m, flight intercept trap, 19–28.VIII.2007, P. W. Kovarik ” ( MCZ) . Paratypes (2): Same data as holotype (1 female MCZ); Chiquibul N. P., Doyle’s Delight, Dry Creek Area, flight intercept trap, 16°29’23’’N, 89°2’45’’W, 20–27.VIII.2007, leg. P. W. Kovarik (1 male MCZ) .

Differential Diagnosis. This new species has a distinctively shaped pronotum: the widest part is slightly past midlength, and the sides in front of and behind the widest part are straight, not emarginate. Based on the male genitalia this species is clearly related to H. pilimera Bojer and Jäch (2011) , although the pronotal shapes differ slightly. It is a member of the H. marginicollis Group ( Perkins 1980), but relationships with other members of the group are uncertain. Reliable determinations will require dissection of males ( Fig. 6 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.67/0.71; head width 0.39; pronotum 0.40/0.57, PA 0.42, PB 0.46; elytra 0.99/0.71. Habitus as illustrated ( Fig. 6 ). Dorsum with head dark brown, pronotum with dark brown very diffusely margined disc surrounded by wide light brown margins, elytra brown, palpi testaceous, tip of last palpomere not darker. Dorsum of head and pronotum moderately coarsely moderately densely punctulate, more sparsely punctulate on pronotal disc than on surrounding areas, interstices shining; punctures of frons disc ca. 1xef, interstices ca. 1xpd; punctures of clypeus very fine, lateral areas microreticulate. Punctures of pronotal disc ca. 2xef, interstices on pronotal disc quite variable, ca. 1–4xpd. Labrum apicomedially excised, free margins weakly upturned. Pronotum with anterior margin emarginate over middle ½, without scintilla; anterolateral pronotal fovea deep, posterolateral and posteromedial foveae absent.

Elytra with summit of posterior declivity slightly beyond midlength; lateral explanate margins wide; on basal 1/3 punctures ca. 1xpd of largest pronotal punctures, punctures becoming gradually smaller toward posterior. Each puncture with fine short recumbent seta. Intervals not raised, width ca. 1xpd, 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 very sparsely very finely punctulate, dull; postmentum very finely densely micropunctulate, dull. Genae raised, shining, without posterior ridge. Ratios of P2 width and plaque shape (P2/w/l/s) ca. 1/1/3/2. P1 laminate; median carina sinuate in profile. P2 l/w ca. 3/1, sides parallel, blunt apex, apex raised slightly above mesoventral intercoxal process. Plaques moderately wide posteriorly, tapering anteriorly, slightly converging toward one another anteriorly, not raised, located at sides of deep median depression. AIS width at straight posterior margin ca. 2.5x P2. Protibia straight, distal ½ distinctly widened on inner margin. Meso- and metatibiae slender, straight. Abdominal apex symmetrical; last tergite with apicomedian notch.

Distribution. Currently known only from the type locality and one nearby site.

Etymology. Named in reference to the geographical distribution and the distinctive, large pronotum.

New species from Mexico

Figures

FIGURE 2. Dorsal habitus of Hydraena species.

FIGURE 6. Hydraena (Hydraenopsis) belicollis new species, holotype habitus and aedeagus.