Hydraena (Hydraenopsis) hosiwergi 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 : 33-36

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

(Figs. 12, 26a–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. 100m, Cabayugan env., 2. 12. 1995, Ján Kodada lgt.”, glued upside down, terminal parts of abdomen and aedeagus glued separately, one protarsal claw lacking. Paratypes: 1 Ψ ( NMW): same locality data as holotype; 10 ɗɗ ( NMW), 19 ΨΨ ( NMW, 1 ex. mutilated): “ PHILIPPINES Sabang, N. of Mt. St. Paul, Palawan July, 11–13, 1977 M. Satô leg.”; 1 ɗ ( UPLB): “ PHIL.: Palawan, P. Princesa Cabayugan R.; Nagdayan Creek, Manturon Bridge, 10°10'N 118°53' E 27.3.2001, leg. Freitag (7)M”; 1 ɗ ( NMW): “ PHIL.: Palawan, P. Princesa Cabayugan R.; Nagdayan Creek, Manturon Bridge 10°10'N 118°53' E 27.3.2001, leg. Freitag (8)M”; 1 Ψ (WPU): “ PHIL.: Palawan, P. Princesa Cabayugan R.; Nagdayan Creek, Manturon Bridge 10°10'N 118°53' E 27.3.2001, leg. Freitag (11)M”; 1 Ψ ( NMW, terminal parts of abdomen lacking): “ PHIL.: Palawan, P. Princesa Cabayugan R.; Nagdayan Creek, Manturon Bridge 10°10'N 118°53' E 27.3.2001, leg. Freitag (12)M”; 1 ɗ ( NMW): “ PHIL.: Palawan, P. Princesa SSW Martarpi 10°09.760'N 118°49.940' E 2.6.2001, leg. Freitag (j13)”; 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 (j43)E”; 1 ɗ ( NMW): “ PHIL.: Palawan, P. Princesa SE Manturon, Karst spring LS4R 10°09'29''N 118°53'30''E 18.III.2001, leg. Freitag (j60) E”; 1 Ψ ( IRML): “ PHIL.: Palawan, P. Princesa SE Manturon, Karst spring LS4R 10°09'29''N 118°53'30''E 21.IV.2001, leg. Freitag (j33) E”; 18 ɗɗ (15 exs. NMW; 2 exs. IRML; 1 ex. WPU), 25 ΨΨ (24 exs. NMW; 1 ex. UPLB): “ Philippines, Palawan centr., Ulangoan river, 18 km NE San Rafael 6. XII. 1995, J. Kodada & B. Rigová lgt.”; 1 ɗ ( NMW): “ PHILIPPINES Olanguan Valley between P. Princesa and Roxas, Palawan 1. IX. 1985 K. Ishikawa leg.”; 1 Ψ ( NMW, mutilated): “ PHIL.: Palawan, Puerto Princesa, Tagabinet River, Bridge near Babuyan R., 10°04'N 118°52' E 25.3.1995, leg. Freitag (1)M”; 2 ɗɗ ( NMW,1 ex. mutilated), 4 ΨΨ ( NMW, 1 ex. mutilated): “ PHIL.: Palawan Brooke’s Point Mate 31.3.1994 leg. Zettel (54)”; 2 ΨΨ ( NMW): “ PHIL.: Palawan, Taytay; 1/3way high-way to Lake Manguao , Manguao Stream trib., prim.forest c. 35m asl, 10°47'N 119°31' E 29.4.1995, leg. Freitag (13b)M”; 13 ɗɗ.(12 exs. NMW; 1 ex. WPU), 8 ΨΨ (5 exs. NMW; 1 ex. IRML; 1 ex. UPLB; 1 ex. WPU): “ PHIL.: Palawan, Taytay; Lake Manguao tributary, Alipuran Stream, semi-prim. forest c. 40m asl, 10°45'N 119°32' E 29.4.1995, leg. Freitag (15)M”; 1 ɗ ( NMW), 2 ΨΨ ( NMW): “ PHIL.: Palawan, P.Princesa; Luzviminda, forest creek, small fall, 9km SSW PPC; sandy banks, pool, c. 50m asl 9°39'N 118°38'E, 14.12.1994,leg.Freitag(17b)M”; 2 ɗɗ (1 ex. NMW; 1 ex. IRML), 3 ΨΨ ( NMW): “ PHIL.: Palawan, P.Princesa; Luzviminda, forest creek, small fall, 9km SSW PPC; side pools w/ leaves, c. 50m asl 9°39'N 18°38'E, 14.12.1994,leg.Freitag(17c)M”.

Description. Body 1.45–1.55 mm long. Habitus as in Fig. 12. Elytra brown; rectangular spot in the middle of pronotal disc dark brown; head medially and anteriorly brown grading into almost black posteriorly and laterally (ocular region); legs, maxillary palpi and (usually) pronotal margins, distinctly pale brown.

Pronotum distinctly wider than long, broadest at the middle (most specimens) or at about anterior 0.35 (some female); entire pronotum densely punctate, sometimes appearing bristled; punctures small and shallowly impressed; interstices of punctures glabrous; foveae inconspicuously impressed or absent; anterior margin slightly concave; anterior angles slightly rounded; lateral rim sometimes inconspicuously denticulate; lateral margins anteriorly and posteriorly convergent; pronoto-elytral angle obtuse; posterior margin slightly biconcave; lateral hypomeron slightly broader than profemur; mesal hypomeron narrow, inconspicuous.

Elytra elongately oval, usually not conjointly rounded apically, with ca. 15 longitudinal, quite irregular rows of punctures (approximately nine between suture and shoulder); punctures small and shallowly impressed; interstices and intervals convex, glabrous; lateral portion of elytra moderately explanate, not reaching elytral apex; posteriorly inconspicuously denticulate; inflexed lateral portion (pseudepipleuron and epipleuron) anteriorly approximately as broad as metafemur; pseudepipleuron reaching ca. posterior 0.25, without row of punctures; epipleuron distinctly narrower and shorter than pseudepipleuron, reaching ca. posterior 0.7.

Mesoventrite. Longitudinal ridges covered by setae, inconspicuous; mesoventral intercoxal process wide, as broad as pseudepipleuron; metaventral disc moderately impressed; metaventral plaques inconspicuous, pubescent; metaventrite and ventrites 1–5 distinctly pubescent.

Femora slightly dilated.

Aedeagus ( Figs. 26 a–c) distinctly differing from that of the other Palawan species. Main piece with various short appendages, without conspicuous setae; phallobase subsymmetric; basal ring not completely closed. Distal lobe intricately shaped, not strongly sclerotized, with numerous conspicuous spinules and papillae, with long sinuous flagellum. Parameres articulately connected with main piece, inserted at about basal 0.2 of aedeagus; left paramere very long and slender, surpassing apex of distal lobe, with a row of mesally directed sinuous long setae, mesal side with a cluster of setae at basal 0.55–0.70 of paramere; right paramere shorter and elongately oval, outer and apical rim densely covered with long bifurcate setae.

Gonocoxite ( Fig. 26 e) subcrescentic; apical area of ventral plate moderately long, setose; setae of subapical tufts slightly curved; basal area not pubescent; condyles moderately large, slightly retracted; dorsal plate simple, basolaterally surpassing outer plate, with two cavities.

Spermatheca ( Figs. 26 f–g). Proximal portion curved; distal portion discoidal.

Secondary sexual characters more distinct than in the other Palawan/ Busuanga species. Metatibiae of male apically very slender, inner side medially unilaterally dilated (Fig. 12); pronotum in some females slightly cordiform, broadest at anterior 0.3. Ventrite 6 distinctly longer and more glabrous in male. Male terminal sternite broadly subtrapezoidal; apical margin rather straight; base rather strongly attenuate, distinctly produced into lateral appendages; spiculum gastrale very long, about four times as long as terminal sternite, slightly curved medially ( Fig. 26 d). Male tergite X apically only slightly excavated, not notched (!), apically foveately depressed, subapically elevated, with a distinct gap. Female tergite X ( Fig. 26 h) distinctly smaller than in male; disc moderately densely covered with rather long setae; subapical fringe of vermiform setae interrupted medially; lateral setae of subapical fringe trichoid; hyaline apical margin medially notched.

Differential Diagnosis. In general appearance and due to the comparably large size this species is not unsimilar to Hydraena scabra , while its colour pattern resembles H. palawanensis , H. pseudopalawanensis and H. manguao . Externally, H. hosiwergi easily can be distinguished from the other known Palawan species by the combination of colour pattern, large size, and elytral and pronotal punctures, which are small and shallowly impressed. Furthermore, the sexual dimorphism of the metatibiae (inner side medially unilaterally dilated in male) is unique among Palawan/ Busuanga species. In contrast to all other species from Palawan/ Busuanga , it is characterized by a robust aedeagus ( H. porcula type), a broadly subtrapezoidal male terminal sternite, and by the male tergite X being not notched apically.

Distribution ( Fig. 31 ). So far known, this species occurs in central Palawan (Cabayugan; Tagabinet; San Rafael) and southern Palawan (Narra; Brooke’s Point).

Ecology. This species was collected in various undisturbed and moderately altered headwaters and residual pools of small streams. Additional material was retrieved from emergence traps positioned over pool sections of first to second order streams. Therefore it is likely that the species inhabits detritus interstitial and avoids strong current.

Figures

FIGURE 26. Hydraena hosiwergi sp. n. a – c) aedeagus (holotype) in ventral (setae of right paramere, mesal setae cluster of left paramere and weakly sclerotized distal lobe omitted), dorsal (margin setae and mesal setae cluster of left paramere omitted) and lateral view (margin setae of left and right paramere and weakly sclerotized distal lobe 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.