Hydraena fundextra, 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 : 131-132

Hydraena fundextra , new species

( Figs. 242 , 244, 416 , 545 )

Type Material. Holotype (male): Morobe Province: Markham Valley, Gusap , c. 90 mi. W of Lae, 305 m, 5° 59' S, 146° 5' E, 27–30 i 1965, M. E. Bacchus (MEB 166) ( NHM) . Paratypes (24): Madang Province: Ramu Valley , 4.5 km N Brahman, [GE est.] 130–150 m, 5° 39' S, 145° 22' E, 18 iv 1991, D. Larson (6 MCZ) ; Ramu Valley , 6 km N Brahman, [GE est.] 130–150 m, 5° 38' S, 145° 22' E, 21 vi 1991, D. Larson (4 MCZ) ; Morobe Province: Same data as holotype (4 NHM) ; Markham Valley, Gusap , c. 90 miles NW of Lae, large pond, muddy bottom with thick layer of dead leaves, dense Ceratophyllum , 305 m, 5° 59' S, 146° 5' E, 27–30 i 1965, M. E. Bacchus (MEB 162) (10 NHM) .

Differential Diagnosis. Among members of the Fundextra group, similar to H. tholasoris in comparatively large size (ca. 1.54 and 1.50 respectively) and in dorsal sculpture ( Figs. 242 , 250 ). Hydraena fundextra has a pronotal macula whereas H. tholasoris has a fascia. The plaque ratios differ in the two species, with H. fundextra having longer and more widely separated plaques compared with P2 (ratios ca. 4/1/8/7 vs. 5/1/7/6); in addition, the plaques are parallel in H. fundextra and anteriorly convergent in H. tholasoris . The male genitalia of H. fundextra distinctively differ from those of other members of the group ( Fig. 244).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.54/0.72; head 0.24/0.37; pronotum 0.38/0.55, PA 0.43, PB 0.51; elytra 0.96/0.72. Dorsum of head with posterior 1/2 of frons dark brown, remainder of frons, clypeus, and labrum light brown to testaceous; pronotum testaceous around light brown, diffusely margined, rectangular macula, ratios of color bands, as measured in midline, ca. 8/12/6; elytra brown; legs light brown; maxillary palpi testaceous, tip not darker. Dorsum shiny.

Frons punctures ca. 1xef, not notably smaller or sparser medially; interstices weakly shining, 0.5–2xpd. Clypeus effacedly microreticulate laterally, very finely sparsely punctulate medially. Mentum very sparsely very finely punctulate, shining. Postmentum effacedly microreticulate in shallow median depression, otherwise finely sparsely punctate. Genae very slightly raised, shining, with shallow, obsolete median impression, without posterior ridge. Pronotum transverse, ca. median 3/5 of anterior margin slightly arcuate to posterior, sides arcuate, slightly emarginate between midlength and posterior angle; punctures on disc slightly larger than largest frons punctures, interstices strongly shining, ca. 2–3xpd, punctures posteriorly slightly larger and denser than those on disc; PF1 and PF4 absent; PF2 very shallow, completely confluent in midline to form U-shaped impression; PF3 deep, wide.

Elytra with posterior declivity very gradual, summit slightly posterior to midlength; lateral explanate margins moderately wide; on basal 1/3 punctures ca. 1xpd of largest pronotal punctures, a few punctures subserial, punctures becoming gradually smaller toward posterior. Intervals not raised, shining, on disc ca. 1–2xpd, as are interstices between punctures of a row. Apices in dorsal aspect conjointly rounded, in posterior aspect margins forming angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 4/1/8/7. P1 laminate; median carina nearly straight in profile, very slightly arcuate between coxae. P2 markedly concave, length/width ca. 3/2, sides very slightly diverging toward blunt apex. Plaques carinate lines, parallel, at sides of densely punctate median depression. Metaventrite between mesocoxae slightly sloping, confluent with tip of P2. AIS width at straight posterior margin ca 1.5x P2. All legs of moderate length. Profemur (male) with small tubercle on ventral margin near basal 1/3; protibia slightly arcuate, posteromedial margin widened to form narrow ridge at about midlength. Meso- and metatibia, straight, slender. Abdominal apex asymmetrical; last tergite (male) with deep concavity near apex, offset to left side. Aedeagus as illustrated ( Fig. 244). Female tergite X, gonocoxite, and spermatheca as illustrated ( Fig. 416 ).

Etymology. Named in reference to the greatly modified right paramere and to the relationship to H. funda .

Distribution. Currently known only from the eastern arm of Area 3; four localities, with an elevation range of 130–305 m ( Fig. 545 ).

Figures

FIGURE 242. Hydraena fundextra, holotype, dorsal and lateral habitus, and venter.

FIGURE 250. Hydraena tholasoris, holotype, dorsal and lateral habitus, and venter.

FIGURES 416–419. Female tergite X, gonocoxite, and spermatheca of Hydraena species.

FIGURES 543–546. Geographical distributions of Hydraena species.