Hydraena (Holcohydraena) chandleri, 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 : 52

Hydraena (Holcohydraena) chandleri , new species

Figs. 2 (habitus comparison), 30 (habitus and aedeagus)

Type Material. Holotype (male): U.S.A.: Florida: “ USA: FL: Taylor Co., 11 mi NW Steinhatchee, V-24-1983 // DSChandler sift leaf litter in wet depressions” ( MCZ) . Paratypes (4): Florida, Taylor Co., 11 mi. NW Steinhatchee, 24.v.1983, leg. Chandler & Reeves, UV light (2 males, 1 female MCZ) . Texas, Sabine Co., 9 mi E. Hemphill, “beech bottom” III-28–IV-2 89, Anderson & Morris, flight intercept trap, Anderson & Morris (1 male MCZ) .

Differential Diagnosis. This new species is a member of the speciose H. circulata Group, having the diagnostic characters of a well-developed posterior ridge of the genae, and the intercoxal segment of the abdomen concave (see figures 21H and 21D in Perkins 1980: 73). Many members of this group require dissection of males for reliable determinations, which is also the case for this species ( Fig. 30 ). It is one of the rare southeastern species of the H. circulata Group.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 2.05/0.89; head width 0.50; pronotum 0.44/0.62, PA 0.53, PB 0.52; elytra 1.28/0.89. Habitus as illustrated ( Fig. 30 ). Dorsum dark brown, palpi and legs brown. Frons and pronotum densely coarsely punctate, interstices dull; punctures ca. 4–5xef, interstices narrow walls to ca. 0.5xpd; clypeus microreticulate, dull. Labrum apicomedially excised, free margins weakly upturned. Pronotum with anterior margin weakly emarginate over middle 1/2; antero- and posterolateral pronotal foveae deep, confluent, posterointernal foveae very shallow.

Elytra with summit of posterior declivity at ca. posterior 1/3; lateral explanate margins wide; on basal 1/3 punctures ca. 1xpd of largest pronotal punctures, some larger punctures rectangular, punctures becoming gradually smaller toward posterior. Intervals slightly raised, width ca. 0.5xpd or less, as are most interstices between punctures of a row, although some separated by narrow walls. Apices in dorsal aspect minutely separately rounded, in posterior aspect margins not forming angle with one another.

Venter: Mentum and postmentum very densely very finely punctulate, dull. Genae raised, dull, with posterior ridge. Ratios of P2 width and plaque shape (P2/w/l/s) ca. 1/1/4/1. P1 laminate; median carina sinuate in profile. P2 l/w ca. 2/1, sides slightly converging toward blunt apex, apex raised slightly above mesoventral intercoxal process. Plaques wide, straight, parallel, weakly raised, located at sides of deep channel-like median depression.AIS concave, width at straight posterior margin ca. 1.5x P2. All tibiae slender, straight. Abdominal apex symmetrical; last tergite apically rounded.

Distribution. Currently known only from one locality each in Florida and Texas.

Etymology. Named in honor of the collector, Donald S. Chandler, renowned Coleopterist.

Remarks. The known localities, in Florida and Texas, are only about 800 miles apart; they are at about the same latitude.

Figures

FIGURE 2. Dorsal habitus of Hydraena species.

FIGURE 30. Hydraena (Holcohydraena) chandleri, new species, holotype habitus and aedeagus.