Hydraena clystera, Perkins, Philip D., 2011

Perkins, Philip D., 2011, New records and description of fifty-four new species of aquatic beetles in the genus Hydraena Kugelann from South America (Coleoptera: Hydraenidae), Zootaxa 3074, pp. 1-198 : 48-49

Hydraena clystera , new species

Figs. 91 (habitus), 94 (aedeagus), 198 (map)

Type Material. Holotype (male): Bolivia: Chulumani, 9–10 vi 1937, H. E. Hinton. Deposited in the BMNH.

Differential Diagnosis. A relatively narrow species, with pronotum subcordate and less transverse than most species (PL/PW ca. 0.87). The metaventrite has very ill-defined, indistinct plaques, and males have distinctively arcuate tibiae. Similar to H. d-concava in dorsal and ventral habitus ( Figs. 91–92 ); refer to the diagnosis of that species.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.28/0.51; head 0.25/0.32; pronotum 0.34/0.39, PA 0.34, PB 0.35; elytra 0.76/0.51. Color uncertain (unique holotype is teneral), mature specimens probably: Dorsum of head piceous; pronotum light brown in front of and behind dark brown fascia (might be macula), ratios of color bands, as measured in midline, ca. 5/10/5; elytra dark brown with light brown, diffusely margined macula across summit of posterior declivity; legs brown; maxillary palpi testaceous, tip not darker.

Frons punctures ca. 0.5–1xef, larger and denser near eyes than medially; interstices effacedly microreticulate, weakly shining, ca. 1xpd laterally, 3–6xpd medially. Clypeus microreticulate, very finely sparsely punctulate medially. Mentum and postmentum very sparsely very finely punctulate, shining. Genae raised, shining, without posterior ridge.

Pronotum subcordiform, weakly arcuate laterally; anterior margin straight behind eyes, emarginate behind frons, scintilla absent; punctures on disc ca. 1xpd of largest punctures on frons, interstices shining, 3–6xpd on disc, punctures larger and denser at anterior and posterior; PF1, PF2 and PF4 absent; PF3 moderately deep.

Elytra weakly arcuate laterally; summit of posterior declivity at ca. midlength; lateral explanate margins narrow; on basal 1/3 punctures ca. 1xpd largest pronotal punctures, punctures becoming finer and more widely spaced toward posterior. Intervals not raised, shining, on basal 1/3 ca. 2–4xpd, as are interstices between punctures of a row, a few punctures subserial. Apices in dorsal aspect conjointly rounded, in posterior aspect margins forming very shallow angle with one another.

P1 slightly wider than laminate; median carina sinuate in profile. P2 moderately wide, l/w ca. 5/4, sides parallel, apex blunt, raised slightly above mesoventral intercoxal process. Plaques obsolete or nearly so, very indistinct lines, located near sides of deep, narrow, triangular 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 ca. 1.2x P2. All tibiae moderately arcuate. Protibia gradually widened from base to ca. distal 2/3, then emarginate to apex, widest part with short setae on medial margin. Meso- and metatibia slender. Abdominal apex symmetrical. Females not yet known.

Etymology. Latin, "syringe"; named in reference to the sharply pointed aedeagus.

Distribution. Currently known only from the type locality ( Fig. 198).

Figures

FIGURE 91. Hydraena clystera, holotype, dorsal and lateral habitus, and venter.

FIGURE 92. Hydraena d-concava, holotype, dorsal and lateral habitus, and venter.