Hydraena herzogestella, 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 : 143-144

Hydraena herzogestella , new species

( Figs. 267 , 269 , 550 )

Type Material. Holotype (male): Morobe Province: Herzog Mts. , Bundun, 700–800 m, 6° 51.598' S, 146° 37.07' E, 2 iv 2006, Balke & Sagata ( PNG 27) ( ZSM) . Paratypes: Same data as holotype (3 ZSM) .

Differential Diagnosis. Very similar in dorsal habitus and ventral structures to the other member of the Fenestella group, H. fenestella ( Figs. 266 , 267 ); differing therefrom in larger size (ca. 1.32 vs. 1.22 mm) and in plaque ratios (ca. 6/1/6/5 vs. 5/1.5/5/4). Reliable determinations will require careful examination of the male genitalia ( Figs. 268, 269 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.32/0.61; head 0.18/0.34; pronotum 0.34/0.50, PA 0.38, PB 0.50; elytra 0.83/0.61. Dorsum of head with frons dark brown, clypeus and labrum brown; pronotum testaceous; elytra dark brown; legs light brown; maxillary palpi testaceous, tip not darker. Dorsum shiny.

Frons punctures ca. 1xef near eyes, smaller and much sparser medially; interstices shining, 1–2xpd laterally, ca. 2–8xpd medially. Clypeus effacedly microreticulate laterally, very finely sparsely punctulate medially. Mentum and postmentum virtually impunctate, very sparsely very finely punctulate, shining. Genae flat or very slightly raised, shining, without posterior ridge. Pronotum subtrapezoidal, ca. median 3/4 of anterior margin slightly arcuate to posterior, side very slightly emarginate between anterior angle and midlength; punctures on disc ca. 1–2xpd of largest frons punctures, interstices strongly shining, ca. 2–6xpd; PF1 absent, PF2 very shallow, obsolete, completely confluent to form one transverse impression, PF3 shallow, PF4 absent.

Elytra with posterior declivity very gradual, summit slightly anterior to midlength; lateral explanate margins narrow. Punctures very small, shallow, ca. 1xpd pronotal punctures, and widely spaced. Intervals shining, ca. 3– 5xpd or greater. 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. 6/1/6/5. P1 ca. 1/3 P2; median carina nearly straight in profile, very slightly arcuate between coxae. P2 markedly concave, length ca. 5/6 width, sides slightly diverging toward blunt apex. Plaques roundly slightly raised, slightly converging anteriorly, at sides of median depression. Metaventrite between mesocoxae slightly concave, conjointly with P2. AIS width at straight posterior margin ca. 5/ 6 P2. All legs of moderate length, tibiae very slender. Profemur (male) with minute sharp tubercle on medial margin near midlength; protibia arcuate, especially in basal 1/2, gradually increasing in width from base to distal 1/3, then slightly narrowing to apex. Meso- and metatibia straight. Abdominal apex symmetrical; last tergite (male) with small apicomedian notch. Aedeagus as illustrated ( Fig. 269 ).

Etymology. Name in reference to the geographical distribution and the relationship to H. fenestella .

Distribution. Currently known only from the type locality, Bundun, Herzog Mts.; this is placed in Area 6, elevation 700–800 m ( Fig. 550 ).

Figures

FIGURE 266. Hydraena fenestella, holotype, dorsal and lateral habitus, and venter.

FIGURE 267. Hydraena herzogestella, holotype, dorsal and lateral habitus, and venter.

FIGURES 268–269. Aedeagi of holotypes. 268. H. fenestella. 269. H. herzogestella.

FIGURES 547–550. Geographical distributions of Hydraena species.