Hydraena (Hydraenopsis) pantitillata Perkins 2023, new species
Creators: name: Perkins, Philip D.
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Hydraenidae
Hydraena
Hydraena pantitillata

description: Hydraena (Hydraenopsis) pantitillata, new species
Figs. 2 (habitus comparison), 28 (habitus and aedeagus)
Type Material. Holotype (male): “ PANAMA: Chiriqui 24km W El Hato del Volcan 3800’ VI.26–27.1976 // flood debris forest stream // A. Newton collector” (FMNH). Paratype: Same data as holotype (1 female FMNH).
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 very wide metaventral intercoxal process, the carinate metaventral plaques (P2/w/l/s ratios ca. 6/1/6/6), and the aedeagus (Fig. 28). The aedeagus cannot be favorably compared with any other known New World Hydraena.
Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.30/0.59; head width 0.33; pronotum 0.33/0.45, PA 0.38, PB 0.38; elytra 0.78/0.59. Habitus as illustrated (Fig. 28). Dorsum brown, head and pronotal disc darker, palpi testaceous, tip of last palpomere not darker. Dorsum of head and pronotum finely sparsely punctulate, interstices shining; punctures of frons disc and pronotal disc ca. 1–2xef, interstices ca. 2–3xpd or slightly larger, each puncture with short, recumbent seta; punctures of clypeus very fine. Labrum apicomedially deeply 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 ca. 1xpd of largest pronotal punctures, punctures becoming gradually smaller toward posterior. Intervals not raised, width ca. 2–3xpd or slightly greater, as are interstices between punctures of a row. Apices in dorsal aspect conjointly rounded, in posterior aspect margins not forming angle with one another.
Venter: Mentum very sparsely very finely punctulate, shining; postmentum very finely punctulate, shining, with concavity on each side. Genae raised, shining, without posterior ridge. Ratios of P2 width and plaque shape (P2/w/l/s) ca. 6/1/6/6. P1 moderately wide; median carina sinuate in profile. P2 very wide, l/w ca. 1/1, sides slightly converging toward blunt apex, apex raised slightly above mesoventral intercoxal process. Plaques carinate, straight, slightly converging toward one another anteriorly, located at sides of deep median depression. Metaventrite with very short longitudinal ridge on each side, extended posteriorly from margin of each mesocoxal cavity. AIS width at straight posterior margin slightly less than width of P2. Protibia (male) with very small, acute process on inner margin slightly distal to midlength. Mesotibia straight. Metatibia inner margin slightly widened. Abdominal apex symmetrical; last tergite with apicomedian notch.
Distribution. Currently known only from the type locality.
Etymology. Named in reference to the spiny aedeagus.
New species from St. Vincent
description: Published as part of 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), pp. 1-86 in Zootaxa 5367 (1) on pages 47-50, DOI: 10.11646/zootaxa.5367.1.1, http://zenodo.org/record/10145106