Hydraena processa, Perkins, 2011

Perkins, Philip D., 2011, New species (130) of the hyperdiverse aquatic beetle genus Hydraena Kugelann from Papua New Guinea, and a preliminary analysis of areas of endemism (Coleoptera: Hydraenidae) 2944, Zootaxa 2944 (1), pp. 1-417 : 111-112

Hydraena processa , new species

( Figs. 198 , 200, 410 , 522 )

Type Material. Holotype (male): Morobe Province: Herzog Mts., Vagau [Wagau], ex dead leaves in small stream in dense forest, 1220 m, 6° 48' S, 146° 48' E, 6 i 1965, M. E. Bacchus (MEB 139) ( NHM) . Paratypes (70): Morobe Province: Same data as holotype (42 NHM) ; Herzog Mts., Vagau [Wagau], ex leaves caught among rocks in shallow clear swift river, 1220 m, 6° 48' S, 146° 48' E, 9 i 1965, M. E. Bacchus (MEB 147a) (20 NHM) ; NE, McAdam Park , [GE est.] 700–900 m, 7° 16' S, 146° 40' E, 29 viii 1968, J. Balogh (No. NG –W–B.38) (8 NHM) .

Differential Diagnosis. Similar to H. bicarinova in body proportions and color ( Figs. 198 , 199 ). These two species are the broadest in the Impala group: the EW/TL ratio is ca. 0.48 for H. bicarinova and 0.47 for H. processa (the ratio varies from 0.40 to 0.48 in the group). Hydraena processa differs from H. bicarinova in the slightly coarser dorsal punctation, the deeper pronotal foveae PF2, and the slightly narrower prosternal intercoxal process (plaque ratios ca. 5/1/5/7 vs. 6/1/5/7). The general plan of the male genitalia of the two species also suggests a relationship, and the genitalia should be examined for reliable determinations ( Figs. 200, 201).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.48/0.69; head 0.20/0.35; pronotum 0.36/0.50, PA 0.38, PB 0.42; elytra 0.92/0.69. Dorsum of head with frons dark brown to dark reddish brown, clypeus lighter, brown, labrum testaceous; pronotum brown around ill-defined dark reddish brown macula on disc; elytra dark brown to reddish brown; legs reddish brown; maxillary palpi light brown to testaceous, tip not darker.

Frons punctures ca. 1–2xef, slightly larger near eyes than medially; interstices shining, 1–2xpd. Clypeus microreticulate laterally, very finely sparsely punctate medially. Mentum and postmentum very sparsely very finely punctulate, shining. Genae raised, shining, without posterior ridge. Pronotum subcordiform, ca. median 3/4 of anterior margin arcuate to posterior; punctures on disc ca. 1xpd frons punctures, interstices shining, 1–3xpd, punctures larger and denser at anterior and posterior; PF1 very shallow, obsolete; PF2 moderately deep; PF3 deep; PF4 very shallow.

Elytra with summit of posterior declivity at or very near midlength; lateral explanate margins rather wide; on basal 1/3 punctures ca. 1xpd largest pronotal punctures, a few punctures subserial, punctures becoming gradually smaller toward posterior. Intervals not raised, shining, on disc ca. 1–3xpd, as are interstices between punctures of a row. Apices in dorsal aspect conjointly rounded, in posterior aspect margins forming shallow angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 5/1/5/7. P1 ca. 2/3 P2; median carina bisinuate in profile. P2 transversely concave, length slightly less than width, sides slightly diverging toward blunt apex. Plaques very narrow, carinate, parallel or very slightly converging anteriorly, at sides of very deep median depression. Metaventrite concave between P2 and plaques, strong ridge extended from each coxal cavity. AIS width at straight posterior margin ca. equal P2. All legs moderately long and slender. Profemur (male) with small tubercle next to trochanter; protibia slightly arcuate, anterior margin very slightly widened subapically, medial margin flat except small sharp tubercle subapically on posteromedial margin. Meso- and metatibia straight. Abdominal apex symmetrical; last tergite (male) deeply notched. Aedeagus as illustrated ( Fig. 200). Female tergite X, gonocoxite, and spermatheca as illustrated ( Fig. 410 ).

Etymology. Named in reference to the S-shaped process of the aedeagus.

Distribution. Currently known from two localities in Area 6; elevations 700–900 m and 1220 m ( Fig. 522 ).

Figures

FIGURE 198. Hydraena processa, holotype, dorsal and lateral habitus, and venter.

FIGURE 199. Hydraena bicarinova, holotype, dorsal and lateral habitus, and venter.

FIGURES 408–411. Female tergite X, gonocoxite, and spermatheca of Hydraena species.

FIGURES 519–522. Geographical distributions of Hydraena species.