Hydraena quintana, 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 : 124-125

Hydraena quintana , new species

( Figs. 227 , 229, 352–357 , 358–361 , 414 , 557 )

Type Material. Holotype (male): Morobe Province: Markham Valley, Lae –Kainantu road, Erap River , ex gravel, [GE est.] 80–130 m, 6° 37' S, 146° 42' E, 26 i 1965, M. E. Bacchus (MEB 156) ( NHM) . Paratypes (43): Central Province: Loloki , 10 miles N of Port Moresby, ex gravel in roadside drain, [GE est.] 30–50 m, 9° 20' S, 147° 10' E, 19 iii 1965, M. E. Bacchus (MEB 209) (2 NHM) ; Loloki , 10 miles N of Port Moresby, ex swamp, much grass, [GE est.] 30–50 m, 9° 20' S, 147° 10' E, 19 iii 1965, M. E. Bacchus (MEB 208) (6 NHM) ; Moitaka , 7 miles N of Port Moresby, ex dead leaves in gravelly shallow of small pond, [GE est.] 30–50 m, 9° 25' S, 147° 12' E, 17 iii 1965, M. E. Bacchus (MEB 207) (24 NHM) ; Moitaka , 7 miles N of Port Moresby, very muddy gravel bank of field drain, [GE est.] 30–50 m, 9° 25' S, 147° 12' E, 17 iii 1965, M. E. Bacchus (MEB 204) (1 NHM) ; Port Moresby – Brown River road, ex grassy shallows of large muddy pond, [GE est.] 50–100 m, 9° 24' S, 147° 14' E, 15 iii 1965, M. E. Bacchus (MEB 195) (5 NHM) ; Morobe Province: c. 7 miles Lae – Bulolo road, ex gravel and grass roots on bank of small stream, [GE est.] 10–30 m, 6° 41' S, 146° 54' E, 30 xii 1964, M. E. Bacchus (MEB 120) (1 NHM) ; Markham Valley, Gusap , 90 miles NW of Lae, ex dead leaves on mud wetted by seepage, 305 m, 5° 59' S, 146° 5' E, 27–30 i 1965, M. E. Bacchus (MEB 163) (4 NHM) .

Differential Diagnosis. Similar to H. ramuquintana in dorsal habitus, small size (ca. 1.23 mm), and subserial to random discal elytral punctures ( Figs. 227 , 230 ); differing therefrom ventrally in plaque ratios, H. quintana having the plaques more convergent anteriorly and P2 narrower (ratios ca. 2/2/7/3 vs. 3/1.5/5/4). Males of the two species are immediately differentiated by the highly modified abdominal ventrites of H. quintana (SEM Figs. 356, 357 , 361 ). The ventrites are similarly modified in H. buquintana , but that species is larger (ca. 1.33 mm), and more strongly punctate dorsally. The male genitalia of all three species in the Quintana group distinctively differ from one another in the shapes of the processes of the distal piece ( Figs. 229, 232, 233 ). The prosternum, meso- and metaventrite, antennal pocket, abdominal apex, and chaetotaxy of the protibiae are illustrated with SEMs ( Figs. 352–357 , 358–361 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.23/0.52; head 0.21/0.28; pronotum 0.31/0.38, PA 0.31, PB 0.36; elytra 0.71/0.52. Dorsum of head dark brown to piceous; pronotum brown to light brown in front of and behind dark brown, diffusely margined, fascia, ratios of color bands, as measured in midline, ca. 6/10/4; elytra dark brown; legs light brown; maxillary palpi testaceous, tip not darker. Dorsum, especially pronotum, strongly shining.

Frons punctures ca. 1xef near eyes, smaller and sparser medially; interstices shining, 1–5xpd. Clypeus effacedly microreticulate laterally, very finely sparsely punctulate and shining medially. Mentum very sparsely very finely punctulate, shining. Postmentum 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 3/4 of anterior margin slightly arcuate to posterior, sides weakly arcuate, slightly emarginate between midlength and posterior angle; punctures on disc very fine and very sparse, slightly smaller than largest frons punctures, interstices strongly shining, ca. 6–8xpd, punctures anteriorly and posteriorly slightly larger than those on disc; PF1 and PF4 absent; PF2 very shallow, obsolete; PF3 moderately deep, wide.

Elytra widest at about anterior 1/3; summit of posterior declivity at or very near midlength; lateral explanate margins narrow; on basal 1/3 punctures subserial or random, ca. 1xpd largest pronotal punctures, punctures becoming gradually smaller toward posterior. Intervals not raised, weakly shining, on disc ca. 1–2xpd. Apices in dorsal aspect conjointly rounded, in posterior aspect margins forming moderately deep angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 2/2/7/3. P1 laminate; median carina sinuate in profile, raised behind coxae. P2 length/width ca. 5/2, sides very slightly diverging toward blunt, raised apex. Plaques large, flat or slightly rounded, at sloping sides of median depression, anteriorly tapering and convergent, narrowly separated at anterior extreme. Metaventrite between mesocoxae raised to joint tip of P2. AIS width at straight posterior margin ca. 2x P2. All legs of moderate length. Profemur (male) without tubercle on ventral margin; protibia straight, medial margin slightly widened in distal 1/2 and with row of short spines. Meso- and metatibia straight, slender. Abdominal apex marked modified in males. Aedeagus as illustrated ( Fig. 229). Female tergite X, gonocoxite, and spermatheca as illustrated ( Fig. 414 ).

Etymology. Named in reference to the modified male fifth abdominal sternum.

Distribution. Currently known from two disjunct lowland areas: the eastern arm of Area 3 (10–305 m), and the central part of Area 11 (30–100 m) ( Fig. 557 ).

Figures

FIGURE 227. Hydraena quintana, holotype, dorsal and lateral habitus, and venter.

FIGURE 230. Hydraena ramuquintana, holotype, dorsal and lateral habitus, and venter.

FIGURES 352–357. Scanning electron micrographs of H. quintana.

FIGURES 358–363. Scanning electron micrographs of H. quintana (358–361) and H. otiarca (362–363).

FIGURES 412–415. Female tergite X, gonocoxite, and spermatheca of Hydraena species.

FIGURES 555–558. Geographical distributions of Hydraena species.

FIGURES 232–233. Aedeagi of holotypes. 232. H. ramuquintana. 233. H. buquintana.