Hydraena multiloba, 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 : 63-64

Hydraena multiloba , new species

Figs. 131 (habitus), 133 (aedeagus), 179 (spermatheca), 201 (map)

Type Material. Holotype (male): Bolivia: Beni, 40 km E. San Borja, Estacion Biologica Beni, Palm Camp at Rio Curiraba, ex. small pool on sand bar, edge of sunlit river, 14 ix 1987, W. E. Steiner. Deposited in the USNM. Paratypes (62): Bolivia: Beni, same data as holotype (34 USNM). Ecuador: Napo, ca. Shushufindi, 0° 18' S, 76° 25' W, 21 ix 1975, Langley & Cohen (2 USNM); Lago Agria, 41 km W, 0° 5' S, 77° 16' W, 18 v 1975, Langley & Cohen (2 USNM); Paraguay: Central, San Lorenzo, u. v. light trap, cool evening, 2 days after a very heavy rain, 11 x 1986, J. Kochalka (1 USNM); Central Dept., Aregua, 26–27 iv 1980, P. J. Spangler (12 USNM); San Bernardino, collected in Arroyo Pirayu, 10 iv 1980, P. J. Spangler, M. M. Culzoni, D. Wood (4 USNM); Dep. Central, Rio Salado N Limpio, 8 vii 1995, Drechsel (2 NMW); Dep. Concepcion, Arroyo Toro paso, 25 x 2002, U. Drechsel (3 NMW); Dep. Pte. Hayes, Transchaco Hwy. km 120, Rio Aguara - Guazu, 22 viii 1995, Drechsel (2 NMW).

Differential Diagnosis. A moderately finely punctate species with piceous pronotal fascia and comparatively narrow elytra. Quite similar in dorsal habitus to H. challeti ( Figs. 131 , 134 ); differentiated therefrom by the smaller size (ca. 1.27 vs. 1.53 mm), the narrower elytra, and the narrower, more widely separated plaques (ratios ca. 2/1/4/ 4). The aedeagi of the two species differ markedly ( Figs. 133, 136).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.27/0.52; head 0.22/0.28; pronotum 0.31/0.40, PA 0.33, PB 0.37; elytra 0.78/0.52. Dorsum of head piceous; pronotum testaceous in front of and behind piceous fascia, ratios of color bands, as measured in midline, ca. 5/12/5; elytra dark brown; legs brown; maxillary palpi testaceous, tip not darker.

Frons punctures ca. 1–1.5xef, slightly larger and denser near eyes than medially; interstices shining, 1–2xpd laterally, 2–5xpd medially. Clypeus microreticulate laterally, very finely sparsely punctulate medially. Mentum and postmentum very sparsely very finely punctulate, shining. Genae raised, shining, without posterior ridge.

Pronotum weakly arcuate laterally; anterior margin straight behind eyes, emarginate behind frons, scintilla absent; punctures on disc ca. 1xpd those of frons, interstices shining, medially ca. 2–4xpd, punctures slightly larger and denser at anterior and posterior; PF1, PF2 and PF 4 absent; PF3 deep.

Elytra rather narrow; 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. 2–3xpd, as are interstices between punctures of a row, a few punctures subserial. Apices in dorsal aspect weakly separately rounded, in posterior aspect margins forming very shallow angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 2/1/4/4. P1 laminate; median carina sinuate in profile. P2 l/ w ca. 2/1, sides parallel, apex raised slightly above mesoventral intercoxal process. Plaques narrow, short, straight, parallel, raised posteriorly, 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 ca. 2x P2. Protibia very slightly, if at all, arcuate. Meso- and metatibia slender, straight. Male abdominal apex symmetrical; last tergite with apicomedian notch. Female (microslide mount, n=1): last tergite sharply rounded, without apicomedian notch, ca. 20 long, rather narrow, hooked setae; gonocoxite not midlongitudinally divided, apical margin sharply rounded, no transverse ridge evident at border of microreticulation; spermatheca type C1; outer margin slightly bulging near junction with accessory gland.

Etymology. Named in reference to the many lobes of the aedeagus.

Distribution. Currently known from Bolivia, Ecuador, and Paraguay ( Fig. 201).

Notes. There is variation in the size and proportions of the lobes on the main-piece of the aedeagus, depending on the collection geographical area. Also, specimens from Ecuador have the lobes on each side of the gonopore larger than those on specimens from Bolivia.

Figures

FIGURE 131. Hydraena multiloba, holotype, dorsal and lateral habitus, and venter.

FIGURE 134. Hydraena challeti, holotype, dorsal and lateral habitus, and venter.