Hydraena (Hydraenopsis) kodadai 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 : 24-26

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

(Figs. 9, 21a–h)

Type locality. Small stream in primary forest, ca. 100 m a.s.l., tributary of Cabayugan River, St. Paul Subterranean River National Park, Cabayugan district, 40 km NNE of Puerto Princesa City, central Palawan, Philippines.

Type material. Holotype ɗ ( NMW): “ Philippines, PALAWAN centr. smal stream in primary forest ca. 100 m, Cabayugan env., 2. 12. 1995, Ján Kodada lgt.”, terminal parts of abdomen and aedeagus glued separately. Paratypes: 2 ΨΨ (1 ex. NMW, 1 ex. UPLB): same locality data as holotype; 1 ɗ ( NMW), 4 ΨΨ ( NMW): “ Philippines, PALAWAN centr., Ulangoan river, 18 km NE San Rafael 6.XII.1995, J. Kodada & B. Rigová lgt.”; 2 ΨΨ ( NMW, 1 ex. mutilated): “ PHIL.: Palawan, P. Princesa Sabang, Waterfall (upper, 30m asl) 10°13'N 118°53' E 26.3.1995, leg. Freitag (19a)”; 1 ɗ ( UPLB): “ PHIL.: Palawan, P. Princesa Panaguman R. 10°15.150'N 118°58.051' E 17.5.2001, leg. Freitag (i25)”; 1 ɗ ( NMW, mutilated), 1 Ψ ( NMW): “ PHIL.: Palawan, P. Princesa Panaguman R. 10°15.150'N 118°58.051' E 17.5.2001, leg. Freitag (e18)”; 1 ɗ ( NMW): “ PHIL.: Palawan, P. Princesa Panaguman R. 10°15.150'N 118°58.051' E 17.5.2001, leg. Freitag (e26)”; 1 ɗ (WPU): “ PHIL.: Palawan, P. Princesa Panaguman R. 10°15.150'N 118°58.051' E 17.5.2001, leg. Freitag (e29)”; 1 ɗ ( NMW): “ PHIL.: Palawan, P. Princesa Panaguman R.PR1, 1.Drift 10°15'09''N 118°58'03''E 17.V.2001, leg. Freitag (a48)”; 1 Ψ ( NMW): “ PHIL.: Palawan, P. Princesa Panaguman R.PR1, 1.Drift 10°15'09''N 118°58'03''E 17.V.2001, leg. Freitag (a49)”; 1 ɗ ( NMW): “ PHIL.: Palawan, P. Princesa SSW Maratarpi Cabayugan R1 10°09'46’’N 118°49'29’’ E 11.12.2000, leg. Freitag (a7)”; 1 Ψ (WPU, mutilated): “ PHIL.: Palawan, P. Princesa SSW Martarpi Cabayugan R.1 10°09'46''N 118°49'29'' E 11.12.2000, leg. Freitag (9)”; 1 ɗ, 1 Ψ ( NMW): “ PHIL.: Palawan, P. Princesa SSW Maratarpi Cabayugan R1 10°09'46’’N 118°49'29’’ E 17.6.2001, leg. Freitag (e10)”; 1 ɗ ( IRML; aedeagus mutilated): “ PHIL.: Palawan, P. Princesa SSW Martarpi Cabayugan R.1, 10°09'46''N 118°49'29''E 1.VII.2001, leg. Freitag (a46)E”; 1 Ψ ( NMW): “ PHIL.: Palawan, Taytay; 1/3way highway to Lake Manguao , Manguao Stream trib., prim.forest c. 35m asl, 10°47'N 119°31' E 29.4.1995, leg. Freitag (13b)M”; 1 Ψ ( IRML) “ PHIL.: Palawan, P. Princesa SSW Maratarpi Cabayugan R1 10°09'46’’N 118°49'29’’ E 16.11.2000, leg. Freitag (e12)”.

Description. Body 1.30–1.45 mm long. Habitus as in Fig. 9. Entire body reddish brown, sometimes goldbrown; frons slightly darker brown, legs and maxillary palpi slightly paler.

Pronotum wider than long, broadest at about posterior 0.3, entire pronotum moderately densely punctate; punctures small and shallowly (posteriorly moderately deeply) impressed, interstices glabrous; foveae hardly perceptible, or absent; lateral margins anteriorly convergent, distinctly sinuously convergent to rectangular posterior angles, forming an almost rectangular pronoto-elytral angle; lateral rim denticulate; anterior margins concave, distinctly broader than straight posterior margin; lateral hypomeron approximately as broad as profemur, inner margin (hypomeral carina) slightly biconvex; mesal hypomeron narrow, imperceptible.

Elytra elongately oval, apex with tiny excision next to sutural keel, with ca. 12 longitudinal, not very regular, unimpressed rows of punctures (seven between suture and shoulder); punctures small and shallowly (basally moderately deeply) impressed, sparsely arranged; interstices and intervals flat, glabrous; lateral gutter of elytra widely explanate, not reaching elytral apex; elytral rim posteriorly finely denticulate; pseudepipleuron anteriorly about as broad as metafemur, reaching posterior 0.2, with indistinct foveae and one inconspicuous row of punctures; epipleuron narrow, short, inconspicuous.

Mesoventrite with well developed longitudinal ridges; meso- and metaventrite, pubescent; abdominal ventrites sparsely pubescent; mesoventral intercoxal process moderately long, very wide; metaventral disc deeply impressed; metaventral plaques distinct, widely separated (wider than inflexed lateral portion of elytra), narrow, glabrous; intercoxal sternite large, approximately as broad as metafemora and as long as broad.

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

Aedeagus ( Figs. 21 a–c) slender, gently evenly curved ventrad and dextrad, with one dorsal subapical seta; dorso-ventrally flattened apically, appearing almost symmetric (ventral/dorsal view); phallobase asymmetric. Distal lobe not clearly delimited from main piece, median portion weakly sclerotized. Parameres articulately connected with main piece, moderately long; each paramere with a row of about 10 moderately long setae; left paramere inserted at about basal 0.50, right paramere at basal 0.55 of aedeagus.

Gonocoxite ( Fig. 21 e) subsemioval; apical area of ventral plate almost as long as basal area; subapical tufts curved; apical margin of basal area with median projection; condyles very small; dorsal plate very simple, slightly surpassing outer plate basally, without cavea.

Spermatheca ( Figs. 21 g–f). Proximal portion extremely large, strongly curved; distal portion discoidal.

Secondary sexual characters. Male usually slightly larger than female. Meso- and metatibia in male slightly curved. Male profemur with (rather inconspicuous) ventro-basal ledge. Male terminal sternite ( Fig. 21 d) oblongly subhexagonal, apical margin rather straight, base broad, distinctly produced into lateral appendages; spiculum gastrale about twice as long as terminal sternite, almost straight. Male tergite X distinctly excised apically. Female tergite X ( Fig. 21 h) subsemicircular, with rather few long discal trichoid setae; subapical fringe with moderately long trichoid setae; hyaline apical margin entire.

Differential Diagnosis. Hydraena kodadai resembles H. zetteli in size, colour and general habitus. Externally, H. kodadai can be distinguished from the latter by its narrower explanate elytral gutter, which ends near apical 0.2 of elytra. Furthermore, H. kodadai can easily be recognized by its posteriorly distinctly convergent pronotum, number of elytral striae (usually 12) and its broad, subsymmetric, bilobed and dorso-ventrally flattened aedeagus, and by its extremely large spermatheca.

Distribution ( Fig. 31 ). Hydraena kodadai is known from four small stream systems in central Palawan.

Ecology. All known macro-habitats are rather undisturbed streams (first to fourth order) surrounded by forest, however, with a remarkable variation in physicochemical conditions. PR1: acidic pH (6.32–7.02), low electrical conductivity (84 µS/cm on average), CR1: alkaline water (pH 8.07–8.45), high conductivity (435 µS/cm on average) due to ultra-basic subsoils ( Freitag 2004). Besides numerous specimens trapped in drift nets, some were collected repeatedly in gravel substrates under a small fall and in moderately fast flowing sections. Obviously, this species prefers (or at least tolerates) higher velocity. However, it was collected several times by emergence traps positioned over a pool section as well.

Etymology. Named for Dr. Ján Kodada (Comenius University, Bratislava, Slovakia), excellent water beetle specialist, who considerably contributed to the knowledge of the fauna of Palawan.

Figures

FIGURE 21. Hydraena kodadai sp. n. a – c) aedeagus (holotype) in ventral, dorsal and lateral view (setae of left paramere omitted); d) male sternite X and spiculum; e) gonocoxite; f – g) spermatheca; h) female tergite X.

FIGURE 31. Collecting sites and geographical distribution of Hydraena species in Palawan and Busuanga, including enlarged map of St. Paul National Park: Hydraena palawanensis sp. n., H. pseudopalawanensis sp. n., H. spp. ΨΨ cf. palawanensis / pseudopalawanensis, Hydraena sp. 1, H. manguao sp. n., H. hosiwergi sp. n., H. busuanga sp. n., Hydraena sp. 2, Hydraena sp. 3.