Hydraena (Hydraenopsis) panelephanta, 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 : 47

Hydraena (Hydraenopsis) panelephanta , new species

Figs. 2 (habitus comparison), 27 (habitus and aedeagus)

Type Material. Holotype (male): “ Panama: Canal Zone : 10 mi. SW Gatun, 1.III.1975 // litter by stream, J. F. Lawrence ” ( MCZ).

Differential Diagnosis. This new species, which is a member of the H. marginicollis Subgroup (see Perkins 1980: 69), can be differentiated from others by the combination of the small body size (ca. 1.30 mm), the pronotum with distinctive dark brown macula surrounded by wide testaceous margins, the pronotum very finely very sparsely punctulate (interstices on disc ca. 3–6xpd or slightly larger), and the aedeagus ( Fig. 27 ). Based on the aedeagus, this species appears to be a distant relative of H. marginicollis , and others with similar basic aedeagal morphology (see figures 53 and 55 in Perkins, 1980).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.30/0.56; head width 0.34; pronotum 0.32/0.44, PA 0.37, PB 0.40; elytra 0.82/0.56. Habitus as illustrated ( Fig. 27 ). Dorsum with head dark brown to black, pronotum with distinctive dark brown macula surrounded by wide testaceous margins, elytra brown, palpi testaceous, tip of last palpomere not darker. Dorsum of head and pronotum very finely very sparsely punctulate, more sparsely punctulate on macula than on surrounding areas, interstices strongly shining; punctures of frons disc and pronotal disc ca. 1xef, interstices on pronotal disc ca. 3–6xpd or slightly larger; punctures of clypeus very fine, lateral areas microreticulate. Labrum apicomedially excised, free margins weakly upturned. Pronotum with anterior margin weakly emarginate over middle 1/2; anterolateral pronotal fovea shallow, other usual foveae absent.

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

Venter:Mentum moderately densely very finely punctulate,each puncture with moderately long seta; postmentum very finely densely micropunctulate. Genae raised, dull, without posterior ridge, with shallow midlongitudinal impression. Ratios of P2 width and plaque shape (P2/w/l/s) ca. 1/1/3/3. P1 laminate; median carina sinuate in profile. P2 l/w ca. 3/1, sides parallel, apex blunt, apex raised slightly above mesoventral intercoxal process. Plaques moderately narrow, straight, parallel, not raised, located at sides of deep median depression. AIS width at straight posterior margin ca. 2.5x P2. All tibiae slender, straight. Abdominal apex symmetrical; last tergite with apicomedian notch.

Distribution. Currently known only from the type locality.

Etymology. Named in reference to the known geographical distribution and the shape of the aedeagus, with a long gonopore-bearing process.

Figures

FIGURE 2. Dorsal habitus of Hydraena species.

FIGURE 27. Hydraena (Hydraenopsis) panelephanta, new species, holotype habitus and aedeagus.