Ancyronyx vincentarnoldi, Freitag & Kodada, 2017

Freitag, Hendrik & Kodada, Ján, 2017, A taxonomic review of the genus Ancyronyx Erichson, 1847 from Sulawesi (Insecta: Coleoptera: Elmidae), Journal of Natural History (J. Nat. Hist.) 51 (9 - 10), pp. 561-606 : 597-599

Ancyronyx vincentarnoldi sp. nov.

( Figures 3 (c); 15(a–d); 18)

Type locality

Small mountain river flowing through secondary forest, 3.3 km northern Kolaka, 57 m a .s .l., c. 04°01′28′′ S, 121°36′16′′ E, Southeast Sulawesi, Indonesia .

Type material

Holotype ♂ ( NMW): ‘ INDONESIA: SE Sulawesi, 3.3 km N Kolaka, small mountain Riv. ; secondary forest; run, submerged wood; 57 m a.s.l., c. 04°01′28′′ S, 121°36′16′′ E 28 Dec.1997 leg. Freitag (Sul2f)’, terminal parts of abdomen including aedeagus glued separately, two tarsi lacking . Paratypes: 1 ♂ ( CKB [ FR110 ]): same data as holotype; 1 ♂, 1 ♀ ( CFM, NMW): ‘ INDONESIA: SE Sulawesi, 8.1 km ENE Kolaka, mountain Riv .; secondary. forest; run, submerged wood; 155 m a .s .l., c. 04°02′06′′ S, 121°40′04′′ E 29 Dec.1997 leg . Freitag (Sul 3f) ’.

Description

Body 1.50–1.85 mm long, 2.1–2.3 times as long as wide (BL/EW), EW: 0.72–0.81 mm. Body form elongate, moderately convex dorsally.

Colouration Figure 3 (c). Pronotum and head black; elytra dominantly dark brown to black with large yellowish patches at apices and elytral disc; legs, antennae, mouthparts (except posterior portion of labrum) yellowish; ventral side dark yellowish to pale brown.

Head. 0.32–0.37 mm wide; ID: 0.19–0.21 mm; labrum and clypeus densely finely punctate, clypeus additionally microstriate, surfaces of both with sparse short hair-like setae; frontoclypeal suture gently arcuate, slightly impressed and conspicuous; frons and vertex finely punctate, with rather irregular distinct granules; eyes moderately protruding. Antennae 11-segmented, slightly longer than head width. Gena and gula transversally microstriate; gular sutures distinct, shallow and oblique.

Thorax. Pronotum slightly longer than wide, widest across posterior 0.4, slightly narrower than elytra; PL: 0.43–0.47 mm, MW: 0.45–0.49 mm; transverse groove shallow; surface anteriorly and posteriorly of transverse groove slightly vaulted; posterolateral oblique grooves arched, narrow and shallow; lateral margins obliquely arcuate; anterior margin distinctly convex, posterior margin slightly trisinuate; pronotal surface strongly irregularly rugulose/reticulate, with inconspicuous punctures and fine pubescence; lateral carina present in posterior third only, inconspicuous; surface of hypomeron similar to those of pronotal disc. Prosternum narrow in anterior portion, prosternal process twice as wide as long, subrectangular, rather flat, posterior margin straight; surface irregularly punctate. Metascutellum broadly subcordiform. Elytra elongate, 1.1–1.2 times as long as wide; EL: 0.85–0.95 mm, EW: 0.72–0.81 mm; sides gently concave, apices separately rounded; disc with 10 slightly impressed and less discernible rows of punctures; rows anteriorly irregularly dissolved; seven rows of punctures between suture and humerus; interstices and intervals narrow, rugulose; elytral margin slightly elevated, narrow; humeri rounded not protruding. Mesoventrite narrow, punctate; mesoventral cavity deep; paired posterolateral impressions shallow. Metaventrite slightly shorter than combined length of pro- and mesoventrite, densely punctate except for shallow postero-median impression; admedian area with elongate setiferous granules; anepisternum 3 short and narrow, with one row of punctures. Hind wings present in all specimens examined.

Legs distinctly longer than body; pro- and mesocoxae large, obliquely drop-shaped, visible in dorsal view; metacoxae obtuse and slightly elevated at articulation with trochanter; trochanter moderately short, pointed distally; femora and tibiae with elongate flat granules; femora deeply excised near articulation with tibia; tibiae and tarsomeres distally with hair-like setae; combined length of tarsomeres 1–4 subequal to length of terminal tarsomere; claws long, strongly bent; base of each claw with three teeth; teeth becoming progressively smaller towards articulation with tarsomere.

Abdomen. Ventrite 1 with intercoxal process short; ventrite 2 short; ventrites 3 and 4 with combined length slightly longer than ventrite 1; ventrite 5 in female longer and in male shorter than ventrite 1; ventrites 1–5 densely punctate; punctures gradually smaller towards apex; surface of ventrites increasingly covered with flat cordiform granules. Male sternite IX ( Figure 15 (a)) deeply excised apically, densely pubescent, without conspicuous spines.

Aedeagus ( Figure 15 (b,c)) 400 µm long. Median lobe moderately long and broad (87 µm), relatively stout, almost parallel-sided up to apical 0.3; apex narrowly rounded, distinctly curved ventrad; ventral sac weakly sclerotized, inflated; fibula weakly sclerotized, slender; corona elongate, conspicuous. Phallobase slightly asymmetrical, basal margin obliquely truncate, moderately sclerotized. Parameres short, elongately subtriangular (lateral view), evenly tapering, with three long setae near apex and a few minute, spine-like setae, reaching about basal 0.68 of aedeagus, almost contiguous ventrally.

Ovipositor ( Figure 15 (d)) distinctly stouter as in all species above; length: 460 µm. Stylus long and slender, slightly bent outwards, with several polymorphic sensilla. Coxite moderately short and stout; with a few hair-like setae near apex and base, with large peg-like setae in distal portion and small acute spines in proximal portion; inner margin finely pubescent. Valvifer about 1.4 times as long as coxite.

Distribution

The species is known from two localities on southeastern Sulawesi ( Figure 18 ).

Etymology

The species is named for Vincent Darius Arnold (Schneeberg, Germany).

Comments

This species may be easily distinguished from any congeners of the A. patrolus group by the larger body size, the characteristic colouration pattern, shape and size of the aedeagus and the stout ovipositor. Some species of the A. variegatus group, however, possess similar shapes of the aedeagi: A. hjarnei Jäch, 2003 (comp. Jäch 2003: Figures 2– 5 ), A. raffaelacatharina ( Figure 16 (b,c)) and A. jaechi Freitag 2012 (comp. Freitag 2012: Figure 2 (a,b)), known from Sulawesi and Sri Lanka, respectively. Ancyronyx schillhammeri Jäch, 1994 from the Philippines resembles in the similar shape of the ovipositor. All these species except A. raffaelacatharina differ from A. vincentarnoldi by the large X-shaped or Y-shaped ( A. hjarnei ) yellow elytral macula and a more or less bicoloured pronotum. Ancyronyx raffaelacatharina differs by the yellow elytral marking being very extensive ( Figure 3 (d)), the pronotal disc being more convex, the apex of the median lobe being widely rounded, the parameres being more narrowed apically ( Figure 16 (b,c)) and by the coxite being distinctly shorter and wider ( Figure 16 (d)).

Ancyronyx vincentarnoldi is a typical lignicolous species. It was collected in small to medium-sized mountain rivers at low altitudes (> 200 m a.s.l.) in rather slow-flowing water. The collection sites were surrounded by secondary forest. Ancyronyx raffaelacatharina was found syntopically.

Figures

Figure 2. Habitus of Ancyronyx species from Sulawesi, (a) Ancyronyx longiparamerus (total length 1.80 mm), (b) Ancyronyx toraja (total length 1.75 mm), (c) Ancyronyx konjo (total length 1.95 mm), (d) Ancyronyx breviparamerus (total length 1.80 mm).

Figure 3. Habitus of Ancyronyx species from Sulawesi, (a) Ancyronyx henningi from Gintu (Sul13f) (total length 1.61 mm; BL: 1.45 mm!), (b) Ancyronyx henningi from Tentena (Sul18 g) (total length 1.58 mm; BL: 1.33 mm!), (c) Ancyronyx vincentarnoldi (total length 1.80 mm), (d) Ancyronyx raffaelacatharina (total length 2.15 mm).

Figure 4. Ancyronyx tobada, (SEM photographs), (a) entire specimen, dorsal; (b) head, pronotum and metascutellum; (c) elytra; (d) antennal tip with digitiform sensillum; (e) terminal antennal segment; (f) entire specimen, ventral; (g) mouthparts, gula, procoxae, pro- and mesoventrite; (h) metacoxae, ventrites 1–5.

Figure 5. Ancyronyx henningi, ventral (SEM photographs), (a) head, pronotum and scutellum, dorsal; (b) head and thorax, ventral; (c) metaventrite, ventrites 1–3, meso- and metacoxae and -trochanter; (d) ventrites 2–5; E: elytra; F: mouthparts; G: antenna.

Figure 15. Ancyronyx vincentarnoldi from Kolaka (male: Sul2f) and (female: Sul3f); (a) male sternite IX, ventral, mutilated; (b) aedeagus, lateral; (c) aedeagus, ventral; D: ovipositor, ventral; (Scale bars = 0.1 mm).

Figure 16. Ancyronyx raffaelacatharina from Dumoga; (a) male sternite IX, ventral; (b) aedeagus, lateral; (c) aedeagus, ventral; (d) ovipositor, ventral; (Scale bars = 0.1 mm).

Figure 18. Map of Sulawesi with collecting site of Ancyronyx species based on their label data.