Hydraena (Hydraenopsis) nielshaggei Freitag & Jäch, 2007

Freitag, Hendrik & Jäch, Manfred A., 2007, Revision of the species of Hydraena Kugelann (Coleoptera: Hydraenidae) from Palawan and Busuanga, with descriptions of eleven new species, and redescription of Hydraena (Hydraenopsis) scabra d’Orchymont, 1925, Zootaxa 1431, pp. 1-44 : 15-17

Hydraena (Hydraenopsis) nielshaggei Freitag & Jäch , sp. n.

(Figs. 5, 17a–h)

Type locality. Cabayugan River, near Nagsatayan Creek, south of Martarpi; 10°09.78'N 118°50.61'E; St. Paul Subterranean River National Park, Cabayugan district, Puerto Princesa City, central Palawan, Philippines.

Type material. Holotype ɗ ( NMW): “ PHIL.: Palawan, P. Princesa S Maratarpi, Cabayugan R. 10°09.780'N 118°15.610' E 16.5.2001, leg. Freitag (a21)”, abdomen and aedeagus glued separately, some parts of legs lacking. Paratypes: 1 Ψ ( NMW, terminal part of abdomen lacking): same locality data as holotype; 1 ɗ ( NMW): “ PHIL.: Palawan, P. Princesa S Maratarpi, Cabayugan R. 10°09.780'N 118°15.610' E 16.5.2001, leg. Freitag (a2)”; 1 ɗ (WPU, aedeagus lacking): “ PHIL.: Palawan, P. Princesa S Maratarpi, Cabayugan R. 10°09.780'N 118°15.610' E 16.5.2001, leg. Freitag (a19)”; 2 ɗɗ ( NMW, 1 ex. mutilated): “ PHIL.: Palawan, P. Princesa S Maratarpi, Cabayugan R. 10°09.780'N 118°15.610' E 16.5.2001, leg. Freitag (a20)”; 1 ɗ ( NMW): “ PHIL.: Palawan, P. Princesa S Maratarpi, Cabayugan R. 10°09.780'N 118°15.610' E 16.5.2001, leg. Freitag (b8)”; 2 ΨΨ ( UPLB; mutilated): “ PHIL.: Palawan, P. Princesa S Maratarpi, Cabayugan R. 10°09.780'N 118°15.610' E 16.5.2001, leg. Freitag (a30)”; 1 Ψ (WPU, mutilated): “ PHIL.: Palawan, P. Princesa S Maratarpi, Cabayugan R. 10°09.780'N 118°15.610' E 16.5.2001, leg. Freitag (d1)”; 1 ɗ ( NMW): “ PHIL.: Palawan, P. Princesa SSW Martarpi Cabayugan R1 10°09'46''N 118°49'29'' E 16.5.2000, leg. Freitag (a24)”; 1 ɗ ( NMW): “ PHIL.: Palawan, P. Princesa SSW Martarpi Cabayugan R.1 10°09'46''N 118°49'29'' E 16.5.2001, leg. Freitag (8)”; 1 ɗ ( NMW): “ PHIL.: Palawan, P. Princesa SSW Martarpi Cabayugan R.1, 10°09'46''N 118°49'29''E 11.XII.2000, leg. Freitag (i44)E”; 1 ex. (WPU, terminal part of abdomen lacking): “ PHIL.: Palawan, P.Princesa; mountain stream 2km SE Laptay/Napsan, semi-prim.forest, 9°43'N 118°28' E 29.3.1995, leg. Freitag (23)M”.

Description. Body 1.05–1.15 mm long. Habitus as in Fig. 5. Elytra and rectangular spot – if present – in the middle of pronotal disc dark brown, otherwise pronotal disc pale grey-brown; frons darker, in most specimens reddish-brown; pronotal margins and legs much paler.

Pronotum wider than long, broadest at posterior 0.3–0.5; entire pronotum densely punctate; punctures moderately large and moderately deeply impressed, interstices glabrous; foveae shallowly impressed and hardly perceptible; anterior margin slightly concave; anterior angles rounded; lateral rim denticulate; lateral margins anteriorly convergent, posteriorly sinuously convergent (inflexed) forming a distinct pronoto-elytral angle; posterior margin straight to slightly bisinuate; lateral portions moderately deflexed; lateral hypomeron approximately as broad as profemora, mesal hypomeron narrow, inconspicuous.

Elytra elongately oval, conjointly rounded apically; with ca. 15 longitudinal, quite irregular, not impressed rows of punctures (10 between suture and shoulder); punctures small and shallowly impressed; interstices and intervals almost flat, glabrous; inflexed lateral portion of elytra moderately explanate, not reaching elytral apex, distinctly narrower than metafemora; rim inconspicuously denticulate posteriorly; epipleuron inconspicuous; pseudepipleuron distinct, reaching ca. posterior 0.25, glabrous, with an indistinct row of punctures.

Mesoventrite with well developed longitudinal ridges; mesoventral intercoxal process short, almost as broad as pseudepipleuron; metaventral disc deeply impressed; metaventral plaques distinct, widely separated (distance wider than inflexed lateral portion of elytra), very narrow, glabrous; intercoxal sternite very large, approximately as broad as metafemur and as long as broad, sub-triangular; metaventrite and abdominal sternites moderately densely pubescent.

Femora with inner margins straight to concave, outer margins conspicuously convex.

Aedeagus ( Figs. 17 a–c) rather simple, elongate and slender. Main piece rather straight, slightly curved to right side (ventral/dorsal view), without setae, with five micropores; phallobase asymmetric. Distal lobe small, with few short amorphic appendages, not clearly delimited from main piece. Parameres very short, almost completely reduced, not articulately connected with main piece; left paramere inserted at about basal 0.55 of aedeagus, with ca. eight moderately long setae (two dorsal apical, one ventral apical, five ventral lateral, arranged in a longitudinal row); right paramere inserted at about basal 0.6 of aedeagus, with ca. eight moderately long setae (five dorsal, three ventral).

Gonocoxite ( Fig. 17 e) subtriangular, rather short; lateral margins strongly convex subbasally, slightly emarginate medially; apical area large; margin between apical and basal area well developed, sinuous; subapical tuft setae curved; basal area without distinct pubescence; condyles prominent; dorsal plate simple, slightly surpassing ventral plate, without distinct cavea.

Spermatheca ( Figs. 17 f–g) very similar to that of Hydraena jojoorculloi .

Secondary sexual characters. Male profemur with tiny denticle near base of ventral face. Metaventral plaques narrower in male; meso- and metatibia in male slightly curved. Male terminal sternite and spiculum gastrale ( Fig. 17 d) very similar to Hydraena jojoorculloi , but micropores at mediolateral portion of terminal sternite less conspicuous, and spiculum gastrale comparatively longer. Male tergite X distinctly excised apically. Female tergite X ( Fig. 17 h) subtrapezoidal; anterior and posterior corners widely rounded; lateral margins evenly rounded; disc sparsely covered with setae; subapical fringe of trichoid setae widely interrupted medially; hyaline apical margin distinctly notched medially.

Differential diagnosis. General habitus and colour resemble Hydraena jojoorculloi , from which it can be distinguished by its slightly smaller size, the slender bent aedeagus with characteristic short amorphic appendages, and by the subapical fringe of trichoid setae of female tergite X.

Distribution ( Fig. 30 ). This species is known from the Cabayugan River and the Ulangoan River, central Palawan. It is most likely endemic to Palawan.

Ecology. The occurrence in headwaters of rather undisturbed, forest-covered areas suggests an affinity to pristine habitats. Most specimens were collected in drift traps. Two specimens were caught in an emergence trap.

Etymology. Named for Niels Hagge (Hamburg), zoologist, for his support during field work in Palawan.

Figures

FIGURE 17. Hydraena nielshaggei sp. n. a – c) aedeagus (holotype) in ventral, dorsal and lateral view; d) male sternite X and spiculum; e) gonocoxite; f – g) spermatheca; h) female tergite X.

FIGURE 30. Collecting sites and geographical distribution of Hydraena species in Palawan and Busuanga, including enlarged map of St. Paul National Park: Hydraena scabra d’Orchymont, H. jojoorculloi sp. n., H. nielshaggei sp. n., H. zetteli sp. n., H. castanescens sp. n., H. claudia sp. n., H. kodadai sp. n.