Hydraena (Hydraenopsis) ateneo, Freitag, Hendrik, 2013

Freitag, Hendrik, 2013, Hydraena (Hydraenopsis) ateneo, new species (Coleoptera, Hydraenidae) and other aquatic Polyphaga from a small habitat patch in a highly urbanized landscape of Metro Manila, Philippines, ZooKeys 329, pp. 9-21 : 12-15

Hydraena (Hydraenopsis) ateneo sp. n. Figs 2A, 3 A–E

Etymology.

The species is named for the Ateneo de Manila University, Quezon City, Philippines, in special recognition of the fiftieth anniversary of the university’s Department of Biology. The type locality of this species lies inside the university campus. The epithet is a proper noun in apposition.

Type material.

Holotype ♂ (PNM): PHIL: Luzon, NCR, Quezon City, Ateneo de Manila Campus; spring creek N of Jesuit Residence, leaf packs; 14°38'29.6"N, 121°04'53.6"E, 62m asl; leg. Vidal, Go & Freitag 16.Nov.2012 (ADM3d)M", terminal parts of abdomen and aedeagus glued separately. Paratypes: 1 ♂, 2 ♀♀ (PNM): same data as holotype; 1 ♂ (CFM): "PHIL.: Luzon, Quezon City, Ateneo de Manila Campus, near San Jose Seminary, temporary headwater creek, leaf litter; 14°38'06.4"N, 121°04'50.2"E, 38m asl.; leg. H. Freitag 28.Jun.2013 (ADM2d)M"; 2 ♂♂, 2 ♀♀ (NMW, SMTD): "leg. Jäch (15) PHILIPPINEN - Luzon Los Banos 24.11.1992 Mt. Makiling 100m"; 1 ♀ (NMW): "leg. Jäch (16) PHILIPPINEN - Luzon W Los Banos 25.11. Rainbow Falls 1992"; 1 ♂, 1 ♀ (CFM): "PHIL.: Luzon, Cavite, Ternate, Lamesang Bato River; hygropetric; sec. forest. 340m asl. 14°14'02"N, 120°38'56"E; coll. R Lagat, M Lagat, JP Bala 16 Apr. 2013 (Ter1j)M"; 5 ♂♂, 3 ♀♀ (CFM): "PHIL.: Luzon, Cavite, Ternate, Lamesang Bato River; littoral pool; sec. forest. 340m asl. 14°14'02"N, 120°38'56"E; coll. Pangantihon 16 Apr. 2013 (Ter1j)M".

Description.

Combined length of pronotum and elytra approximately 1.10-1.14 mm; entire specimen about 1.25-1.33 mm long, 0.58-0.62 mm wide. Dorsal habitus as in Fig. 2A. Elytra brown; pronotum gold-brown with brown sub-rectangular median pattern; frons dark brown; legs, maxillary palpi, and antennae distinctly paler yellowish brown.

Head partly retracted; labrum very slightly excised medially; clypeus moderately densely micropunctate; fronto-clypeal suture slightly concave; frons densely punctate; punctures small and slightly impressed, interstices glabrous; gula rugulose, rest of head venter almost glabrous.

Pronotum about 1.4 times as wide as long, widest at the middle, narrower than elytra; entire pronotum densely punctate; punctures moderately large and moderately deeply impressed, interstices glabrous; anterior margin concave; anterior angles slightly rounded; lateral rim entirely denticulate; lateral margins anteriorly convergent, posteriorly sinuously convergent; pronoto-elytral angle obtuse; posterior margin slightly convex; lateral hypomeron about as wide as profemur. Prosternite carinate, rugulose; mesoventrite with rather indistinct longitudinal ridges, rugulose; mesoventral intercoxal process narrow, distinctly narrower than pseudepipleuron.

Elytra elongately oval, about 1.55 times as long as wide; each elytron with a tiny apical excision next to sutural keel, with about nine, more or less regular rows of punctures between suture and shoulder; punctures moderately large and moderately deeply (apically shallowly) impressed; interstices and intervals glabrous; lateral portion explanate from anterior 0.1 to posterior 0.2; pseudepipleuron anteriorly almost as wide as metafemur, reaching posterior 0.15; epipleuron narrow, short. Metaventral disc slightly impressed; metaventral plaques hardly discernible with stereoscopic microscope, appear as narrow, flat bands; intercoxal segment (abdominal sternite II) slightly wider than long; prosternite, meso-, metaventrite and ventrites 1-4 densely pubescent and rugulose; ventrites 5-6 more or less glabrous, only slightly pubescent.

Femora with almost straight inner margin, outer margin distinctly convex; meso- and metatibiae almost straight, outer faces with few long trichoid setae (sometimes broken off); mesotibia additionally with conspicuous row of short, spine-like setae at inner and outer margin; protibia entirely slightly bent inwards, outer margin slightly convex, inner margin slightly concave to almost straight.

Aedeagus (Figs 3A, B): Elongate and distinctly bent; main piece more or less straight in ventral view, sinuously curved in lateral view, without setae (some micropores present); phallobase almost symmetrical. Distal lobe long and more or less straight, but bent in 45° angle from main axis, distally tapered, appearing entirely densely freckled or stippled by microstructures; distal lobe embedded in a membranous, transparent, elongate structure. Flagellum very long, bisinuously curved, inserted laterally near right paramere. Parameres firmly fused to main piece; left paramere moderately long and moderately wide, inserted at about basal 0.65 of main piece, latero-apically with approximately five and apically with about four moderately long setae; right paramere extremely short, wider than long; inserted at about basal 0.9 of main piece, with ca. four, almost parallel, long setae.

Gonocoxite (Fig. 3D): Roundly subtrapezoidal, lateral margin slightly convex; setae of subapical tufts straight; margin between apical and basal area uneven, but well developed; apical area moderately densely pubescent; basal area of ventral plate almost without setae; condyles conspicuous; dorsal plate not surpassing outer plate, with two indistinct, separate cavities (hardly discernible in some specimens).

Spermatheca as in Fig. 3C.

Secondary sexual characters.

Male profemur with three tiny denticles at basal 0.3 of ventral face (compound microscope recommended). Male terminal sternite sub symmetrically pyriform to elongately subtriangular; base slender, slightly produced laterad; spiculum gastrale almost twice as long as terminal sternite, slightly bent. Male tergite X apically distinctly excised, slightly asymmetrical. Female tergite X (Fig. 3E) subsemicircular; lateral margins evenly rounded; disc moderately densely covered with trichoid setae; setae of subapical fringe short, more or less truncate; each lateral side with one long and several short trichoid setae; hyaline apical margin notched medially.

Differential diagnosis.

This species resembles externally Hydraena castanescens from which it can be easily distinguished by the smaller size and by its straight metatibiae in both sexes. Furthermore, it can easily be recognized by its aedeagus (distal lobe elongate, freckled, enveloped in a membrane; flagellum very long, bisinuously curved). From the two syntopic species, Hydraena scabra and Hydraena palawanensis , it can be distinguished by the medium size (1.25-1.33 mm long), the moderately large and moderately deeply impressed elytral punctures, and the shape of aedeagus, gonocoxite and tergite X.

Distribution.

So far only known from central Luzon (Quezon City, Cavite, Laguna).

Ecology.

This species was collected from small, slow flowing headwater creeks with secondary vegetation cover, where it was found among submerged leaf litter.