Ancyronyx helgeschneideri 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 : 55-58

Ancyronyx helgeschneideri Freitag & Jäch sp. n.

( Figs. 10 , 16 a–h)

Type locality. Cabayugan River, St. Paul National Park, Cabayugan District, Puerto Princesa City, Palawan, Philippines.

Type material. Holotype ď ( NMW): “ PHIL.: Palawan, P. Princesa S Manturon, Cabayugan R. 10°09'16''N 118°52'30'' E 17.6.2000, leg. Freitag (CR3)M”, dissected (terminal parts of abdomen, aedeagus and one tarsus glued separately), one distal tarsal segment lacking, right aedeagal paramere incomplete. Paratypes: 1 ď ( NMW): “ PHIL.: Palawan, P. Princesa S Manturon, Cabayugan R. 10°09'16''N 118°52'30'' E 25.5.2001, leg. Freitag (CR3)D”; 2 ΨΨ ( NMW, UPLB): “ PHIL.: Palawan, P. Princesa S Manturon, Cabayugan R. 10°09'28''N 118°53'26'' E 25.5.2001, leg. Freitag (CR4)D”; 1 Ψ ( MTD): “ PHIL.: Palawan, P. Princesa Panaguman R. 10°15'09''N 118°58'03'' E 17.5.2001, leg. Freitag (PR1)D”.

Description. Body 1.7–2.0 mm long (CL), 0.76–0.86 mm broad (EW), 2.4–2.6 times as broad as wide (CL/EW). Body form elongately oval, moderately convex dorsally.

Colouration ( Fig. 10 ). Labrum brown laterally, slightly paler in middle; mouth parts and antennae yellowish; frons and clypeus dirty yellowish; small area around the eyes and remainder of head dark brown to black; pronotum yellowish, lateroposteriorly and anteriorly dark brown to black; at least margins of scutellum dark; elytra dark brown, medially with a subquadrate or X-shaped yellowish marking, apices yellowish; ventral side yellowish; coxae pale yellowish; femora yellow (one specimen with indistinct dark anterodorsal median spot on middle and hind femur); tibiae basally black, distally yellowish; tarsomeres basally dark brown, distally yellowish; claws pale reddish brown.

Plastron hardly discernible with stereoscopic microscope, not examined.

Head 0.40–0.46 mm broad (HW); ID 0.22–0.26 mm; labrum and clypeus micropunctate; setae distinct; frons granulose, granules arranged in longitudinal lines; frontoclypeal suture slightly arcuate, distinctly impressed. Eyes protruding. Antennae 11-segmented, slender, rather long (longer than HW). Gula microgranulose; gular sutures conspicuous, mesally narrowly separated.

Pronotum 0.53–0.58 mm long (PL), 0.67–0.71 mm broad (MW), distinctly wider than long (PL/MW: ca. 0.8), widest at about posterior 0.4, anteriorly attenuate; anterior margin moderately arcuate; margin between pronotum and hypomeron inconspicuous; anterior part with inconspicuous mesal longitudinal carina; anterior transverse groove distinct and deeply impressed, seemingly dividing the pronotum; posteriorly of transverse groove with conspicuous gibbosity; posterolateral oblique grooves moderately deeply impressed; pronotal surface and hypomeron reticulate. Prosternum irregularly punctate; prosternal process distinctly transverse, medially slightly impressed, posterior margin subtruncate.

Scutellum subpentagonal, glabrous. Elytra elongate, 1.18–1.39 mm long (EL), ca. 1.5–1.7 times as long as wide (EL/EW), very slightly convergent in anterior 0.1–0.7, posteriorly roundly convergent to apices; with ca. 10 longitudinal, quite regular rows of punctures (seven strial rows between suture and shoulder); punctures large and deeply impressed, except in the almost flat anterior area; interstices and intervals flat to convex, rugulous; lateral elytral gutter very narrow; humeri moderately prominent; elytral apices conjointly rounded.

Meso- and metaventrite moderately densely granulose and pubescent, lateral parts distinctly punctate. Mesoventrite very short, with one medial and a pair of sublateral impressions. Metaventrite prominent, with distinct discrimen; anepisternum 3 not visible in ventral view, with one row of deeply impressed punctures. Hind wings present.

FIGURE 17. Collecting sites and geographical distribution of Ancyronyx species in Palawan and Busuanga, including enlarged map of St. Paul National Park: Ancyronyx patrolus sp. n., A. pseudopatrolus sp. n., ♦ A. punkti sp. n., A. minerva sp. n., A. minutulus sp. n., A. helgeschneideri sp. n.

Ventrites granulose, pubescent.

Legs approximately 1/4 longer than body; pro- and mesocoxae large, bluntly drop-shaped; metacoxae distinctly smaller and only slightly protruding laterally; femora, tibiae, and tarsi covered with inconspicuous setae, tibiae with few additional longer setae; distal tarsal segments with several conspicuous setae near base of claws; claws well developed, base with three teeth, basal one very small and hardly discernible.

Sternite IX ( Fig. 16 c) ca. 450 µm long; apical margin distinctly emarginate, lateroapically finely striolate and covered with microsetae; paraprocts not or only slightly reaching beyond apical margin. Tergite VIII in both sexes without distinct reticulation, with conspicuous median transverse complete ridge separating posterior and anterior portion; basal half with microstrial pattern; apical half darker, with hyaline apical margin and subapical fringe of trichoid setae, with ca. six conspicuously strong and very long setae.

Aedeagus ( Fig. 16 a, b) ca. 440 µm long. Median lobe rather short and conical, subapically distinctly curved ventrad (lateral view), with numerous distinct microtube-like structures, most conspicuous apically; ventral sac apically ending in two separately tapered tips, mediobasally plicate; fibula inconspicuous; corona weekly developed. Phallobase asymmetrical, approximately half as long as parameres. Parameres long (almost reaching apex of aedeagus), dorsally widened at base (lateral view), ventral margin distinctly sinuous; basal margin emarginate, not contiguous ventrally.

Ovipositor ( Figs. 16 d). Total length ca. 480 µm. Stylus slender, very slightly bent outwards (dorsal view). Coxite short and stout, distal portion with several rather short and broad, peg-like setae, most densely set lateroapically; inner margin moderately pubescent; basal portion approximately as long as distal portion, with rather short, peg-like setae, most densely set at lateral margin, medially with striolate patches. Valvifer slightly longer than coxite, apical margin with one long spine, finely striolate near apex; fibula curved inwards caudally.

Secondary sexual characters. Sternite VIII ( Fig. 16 g) in male weekly sclerotized, without conspicuous setae; median strut short, apically roundly tapered; female sternite VIII not dissected. Tergite VIII in male ( Fig. 16 e) distinctly broader than long, condyles straight and prominent. Tergite VIII in female ( Fig. 16 h) slightly broader than long; condyles inconspicuous, more or less straight and not distinctly reaching beyond anterior margin. Ventrite 5 in male ( Fig. 16 f) suboval, in female similar, but longer and more subtriangular.

Differential diagnosis. The general habitus and colour patterns of this species somewhat resemble A. procerus Jäch, 1994 (see Fig. 28, Jäch 1994), from which it can be distinguished by smaller size, long aedeagal parameres and presence of a spine on the valvifer.

Distribution (Fig. 17). This species is known only from the St. Paul National Park, central Palawan.

Ecology. The distribution of this species in river courses distinctly varying in their morphology and physicochemical character (CR3 vs. PR1; see Freitag 2005), including slightly disturbed sections suggests a higher ecological tolerance. This species seems to prefer stream sections of medium order.

Etymology. Named for Helge Schneider, famous German multi-talented artist, with special interest in animal wildlife.

Figures

FIGURE 16. Ancyronyx helgeschneideri sp. n., ♂ paratype from CR 3, Ψ paratype from PR 1: a, b) aedeagus in ventral and lateral view; c) male sternite IX (one paraproct omitted); d) ovipositor in ventral view (left half); e) male tergite VIII (setae and strioles of left half omitted); f) male ventrite 5 (setae and strioles of left half omitted); g) male sternite VIII (strioles omitted); h) female tergite VIII (setae and strioles of left half 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.