Ancyronyx minerva Freitag & Jäch, 2007

Freitag, Hendrik & Jäch, Manfred A., 2007, The genus Ancyronyx Erichson, 1847 (Coleoptera, Elmidae) in Palawan and Busuanga, (Philippines) with descriptions of six new species, Zootaxa 1590, pp. 37-59 : 50-53

Ancyronyx minerva Freitag & Jäch sp. n.

( Figs. 7, 8 , 14 a–j)

Type locality. Mountain river SE of Laptay/Napsan, central Palawan, Philippines.

Type material. Holotype ď ( NMW): “ PHIL.: Palawan, P.Princesa; Napsan 2km SE Laptay, 9°43'N 118°28' E 29.3.1995, leg. Freitag (23)M \ mountain stream in semi-primary forest”, winged, terminal parts of abdomen incl. aedeagus glued separately, two tarsi lacking. Paratypes: 41 exs., five of them winged (1 ď IRML; 8 ďď, 11 ΨΨ, 19 exs. NMW; 1 ď UPLB; 1 Ψ WPU): same data as holotype; 10 ďď, 7 ΨΨ ( NMW): “ PHIL.: Palawan, P.Princesa; Luzviminda, 9km SSW PPC; 9°39'N 118°38' E 14.12.1994, leg. Freitag (17a)M \ forest creek, small fall, rocky bank, riffle, ca. 50m asl”; 2 ďď, 2 ΨΨ ( NMW): “ PHIL.: Palawan, P. Princesa, Iwahig, Balsahan River, 7km NW of PPC, upstream of dam 9°47'N 118°40' E 0 5.3.1994, leg. Freitag (20)M”; 31 exs. (10 ďď, 10 ΨΨ MTD; 8 ďď, 3 ΨΨ NMW): “ PHIL.: Palawan, P. Princesa, Irawan River, 6km NW of PPC, 2km upstream of water plant 9°49'N 118°39' E 0 6.4.1994, leg. Freitag (60)M”; 2 ďď, 2 ΨΨ, one of them winged ( NMW): “ PHIL.: Palawan, Brookes P., Sabsaban River, c. 10km NW of town proper, downstream falls, riffle woodlitter, 8°49'N 117°48' E 20.5.1994, leg. Freitag (79a)M”; 72 exs., two of them mutilated (1 ď, 2 ΨΨ IRML; 15 ďď, 33 ΨΨ, one of them winged, 15 exs. NMW; 1 ď, 2 ΨΨ UPLB; 2 ďď, 1 Ψ WPU): “ PHIL.: Palawan, P. Princesa Panaguman R. 10°15'09''N 118°58'03'' E 17.5.2001, leg. Freitag (PR1)D”; 1 Ψ ( NMW): “ PHIL.: Palawan, P. Princesa S Maratarpi, Cabayugan R. 10°09'47''N 118°50'37'' E 16.5.2001, leg. Freitag (CR2)D”; 2 ďď, one of them winged ( NMW): “ PHIL.: Palawan, P. Princesa S Manturon, Cabayugan R. 10°09'16''N 118°52'30'' E 25.5.2001, leg. Freitag (CR3)D”; 1 Ψ, winged ( NMW): “ PHIL.: Palawan, P. Princesa S Manturon, Cabayugan R. 10°09'28''N 118°53'26'' E 25.5.2001, leg. Freitag (CR4)D”.

Description. Body 1.2–1.3 mm long (CL), 0.49–0.60 mm broad (EW), 2.0–2.6 times as broad as wide (CL/EW). Body form subovate, strongly convex dorsally.

Colouration ( Figs. 7, 8 ) predominantly dark brown or black (labrum, clypeus, frons, pronotum except anterior margin, scutellum, most parts of elytra); elytra with two pairs of white to yellowish patches; ventral side pale brown to medium brown, but always paler than dark dorsal parts, except gula; maxillary palpi, coxae, and femora (at least dorsally) dark brown; mesal portions of tibiae and tarsal segments yellowish to pale brown; areas around knees, tarsomeres, and claws dark brown; antennae yellowish to pale brown, distally darkened.

Plastron hardly discernible with stereoscopic microscope, not examined.

Head 0.28–0.30 mm broad (HW); ID 0.15–0.19 mm; labrum slightly pubescent, appearing glabrous; frons and clypeus with fine punctures, moderately densely pubescent; frontoclypeal suture arcuate, slightly impressed. Eyes moderately protruding. Antennae 11-segmented, slender, slightly longer than HW. Gula microreticulate, with transverse stria; gular sutures absent.

Pronotum 0.34–0.39 mm long (PL), 0.38–0.44 mm broad (MW), distinctly narrower than elytra, ca. 0.8– 0.9 times as long as wide (PL/MW), widest at ca. posterior 0.35, anteriorly attenuate; anterior margin nearly straight; margin between pronotum and hypomeron inconspicuous; anterior transverse groove distinct and deeply impressed, seemingly dividing pronotum, medially extended posteriorly; anteriorly and posteriorly of transverse groove vaulted; posterolateral oblique grooves small, distinctly impressed; pronotal surface reticulate to granulose, with some glabrous parts; hypomeron microreticulate. Prosternum granulose to punctate; prosternal process subquadrate; posterior margin truncate.

Scutellum subtriangular, granulose. Elytra 0.82–0.92 mm long (EL), 1.4–1.7 times as long as wide (EL/ EW), roundly ovate; elytra in winged specimens elongate, almost parallel-sided in anterior 0.1–0.6, posteriorly roundly convergent to apices, 0.82–0.94 mm long (EL), ca. 1.55–1.70 times as long as wide (EL/EW); posteriorly with ca. nine longitudinal, quite regular, slightly impressed rows of punctures (five strial rows between suture and shoulder); punctures moderately large and moderately deeply impressed, indistinct at yellowish patches; interstices and intervals convex, glabrous; lateral elytral gutter very narrow; humeri inconspicuous in wingless specimens; elytral apices almost commonly rounded. Mesoventrite short, medial groove distinct, anterior margin bisinuate, posterior margin concave. Metaventrite prominent; longitudinal groove in some specimens distinct and moderately long, in other specimens very short at posterior margin, medioanteriorly almost glabrous, medially impressed; lateral parts covered with large glabrous punctures/granules; anepisternum 3 moderately prominent, with rather superficial rows of punctures, conspicuously differentiated from lateral elytron. Hind wings present in seven of 134 specimens examined; wing venation very similar to Ancyronyx punkti , but radial cross-veins hardly discernible.

Five visible abdominal ventrites covered with glabrous granules; ventrite 1 anteriorly with indistinct shallow punctures ( Fig. 14 e, f).

Legs slightly longer than body; pro- and mesocoxae large, somewhat drop-shaped; metacoxae only slightly protruding, elongately oval; all femora covered with distinct setae, except on ventral (inner) side; tibiae and tarsi rather inconspicuously setose, tibiae distally with a group of distinct setae; claws well developed, strongly curved, base of each claw with two teeth, distal one much larger than basal one.

Sternite IX ( Fig. 14 c) ca. 310 µm long; apical margin distinctly emarginate, lateroapically with groups of ca. 10 setae; paraprocts not reaching apical margin.

Aedeagus ( Fig. 14 a, b) ca. 330 µm long. Median lobe moderately long and slender (max. ca. 55 µm broad), subapically distinctly acuminate; apical tip rounded, slightly curved ventrad (lateral view), with numerous distinct microtube-like structures ending within a small lateroapical fringe; ventral sac well developed, ventral side moderately sclerotized and convex (lateral view), only basally distinctly plicate; fibula moderately sclerotized, conspicuous; corona weekly developed. Phallobase asymmetrical, basally slightly acuminate and curved ventrad (lateral view), with conspicuous, strongly sclerotized margin; basolateral (penile) apophyses rather long. Parameres broadly elongate (lateral view), reaching ca. basal 0.70 of aedeagus; basal margin sinuately emarginate (lateral view), clearly not contiguous ventrally.

Ovipositor ( Figs. 14 d). Total length ca. 530 µm. Stylus moderately broad, slightly bent outwards (dorsal view). Distal portion of coxite slender and almost straight (lateral view); lateral margin distinctly concave, mesal margin straight (dorsal view); apex surrounded by incomplete wreath of squamous setae; medially moderately densely covered with squamous or cone-like setae; inner margin pubescent; basal portion ca. 0.6 times as long as distal portion, with cone-like setae. Valvifer about as long as coxite; fibula rather slender, curved inwards caudally, cranially slightly acuminate.

Secondary sexual characters. Sternite VIII in male ( Fig. 14 g) weekly sclerotized, without setae; median strut distinctly shorter than in female, apically rounded; sternite VIII in female ( Fig. 14 j) with median strut slightly widened apically, almost truncate, with two rows of isolated setae lateroposteriorly (this area brown and conspicuously darker than remaining parts). Tergite VIII in male ( Fig. 14 h) broader than long, subcrescentic, distinctly reticulate in apical half; basal half with microstrial pattern; condyles inconspicuous; tergite VIII in female ( Fig. 14 i) slightly longer than broad, subcrescentic; microstrial pattern medially extended into apical half; condyles more prominent and distinctly reaching beyond anterior margin. Ventrite 5 in male ( Fig. 14 e) suboval, in female ( Fig. 14 f) longer and subtriangular.

Differential diagnosis. Externally, this species is characterized by small size and pronotal colour pattern. Aedeagal apex acuminate.

Distribution (Fig. 17). This species is known from localities in central and southern Palawan.

Figures

FIGURE 14. Ancyronyx minerva sp. n., ♂ holotype, Ψ paratype from same locality: a, b) aedeagus in ventral and lateral view; c) male sternite IX (strioles omitted); d) ovipositor in ventral view (left half); e) male ventrite 5 (setae and strioles of left half omitted); f) female ventrite 5 (setae and strioles of left half omitted); g) male sternite VIII (strioles omitted); h) male tergite VIII (setae and structures of left half omitted); i) female tergite VIII (setae and strioles of left half omitted); j) female sternite VIII (strioles omitted).

FIGURES 7 – 10. Habitus of 7) Ancyronyx minerva sp. n., paratype Ψ; 8) A. minerva sp. n., paratype Ψ, winged, partly completed; 9) A. minutulus sp. n., holotype ♂, partly completed; 10) A. helgeschneideri sp. n., paratype Ψ.