Ancyronyx tobada, 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 : 578-581

Ancyronyx tobada sp. nov.

( Figures 1 (c); 4(a–h); 8(a–d); 18; 19(a,b)

Type locality

Mountain brook in cloud forest, road km 43 Tentena-Gintu, ca . 01°48′39′′ S, 120°23′17′′ E, c. 1680 m a.s.l ., Sulawesi, Indonesia .

Type material

Holotype ♂ ( NMW): ‘ INDONESIA: C Sulawesi, Rd. Km 43 Tentena-Gintu ; mountain creek; cloud forest; submerged wood, c. 1680 m a.s.l., c. 01°48′39′′ S, 120°23′17′′ E 04 Jan.1998 leg. Freitag (Sul14f)’, abdomen incl. aedeagus glued separately . Paratypes: 3♂♂, 1♀ ( NMW, CKB, CFM [FR111]) with same data as holotype; 4♂♂, 5♀♀ ( NMW, CFM [FR118]): ‘ INDONESIA: C Sulawesi, Rd . Tentena-Pendola, 9 km E Tentena , sec . forest; submerged wood, c. 860 m a.s.l., c. 01°46′31′′ S, 120°43′05′′ E 03 Jan.1998 leg . Freitag (Sul 10f)’; 7♂♂, 5♀♀, ( CFM): ‘ INDONESIA: S Sulawesi, Rd . Km 56 Tentena-Gintu; Tentena , black-water river; submerged wood, c . 1190 m a.s.l., c. 01°49′28′′ S, 120°21′43′′ E 04 Jan.1998 leg . Freitag (Sul 16f) ’.

Description

Body 1.33–1.50 mm long, EW: 0.62–0.70 mm; body form elongate, 2.1–2.2 times as long as wide (BL/EW), convex dorsally.

Colouration Figure 1 (c). Predominantly dark brown to black; elytra with more or less conspicuous large roundish pair of pale brown/yellowish patches extending from humeri up to first interval; oblique posterior pale patches usually visible, but commonly rather faint. Pronotum and head black; femorotibial articulations always dark brown; coxae, femora, proximal half of tibiae, tarsomeres 1–4, distal half of terminal tarsomeres, claws, maxillary palps and antennal tip brown to varying extent; preterminal antennomeres, proximal half of tarsomere 5, distal half of tibiae and often also median portion of profemora distinctly paler brown to dark yellowish. Ventral side dark brown.

Head. HW: 0.34–0.37 mm, ID: 0.17–0.21 mm; labrum with sparse fine punctures and pubescence; frontoclypeal suture straight and discernible; frons and vertex with dense longitudinal granules ( Figure 4 (b)), similar structures on lateral portion of clypeus, but less pronounced; eyes moderately protruding. Antennae ( Figure 4 (b)) slightly longer than head width; terminal antennomeres with short digitiform sensillum ( Figure 4 (d,e)). Gular region transversally microstriate ( Figure 4 (g)); gular sutures visible in anterior third.

Thorax. Pronotum ( Figure 4 (a,b)), wider than long, widest at about posterior 0.4, distinctly narrower than elytra; PL: 0.40–0.43 mm, MW: 0.46–0.49 mm; transverse groove deep; surface anteriorly and posteriorly of transverse groove distinctly vaulted; posterolateral oblique grooves rather moderately deep (in one female ‘Sul14f’ deep); anterior mesal longitudinal carina absent; lateral margins arcuate; anterior margin convex, posterior margin feebly trisinuate; pronotal surface with puncture interstices raised, appears rugulose, pubescence very fine and indiscernible under stereo microscope; lateral pronotal carina absent; hypomeron smoother than pronotal surface. Prosternum ( Figure 4 (g)) densely rugosely punctate, with small granules; prosternal process 1.3 times as wide as long, broadly subpentagonal; portion in front of procoxae short, along midline c.0.4 times as long as prosternal process. Metascutellum ( Figure 4 (b)) pentagonal, with few granules. Elytra elongate ( Figures 1 (c), 4(c)), EL: 0.97–1.13 mm, EW: 0.62–0.70 mm, 1.5–1.6 times as long as wide, nearly parallel-sided in anterior 0.05–0.60; apices almost conjointly rounded; 11 rows of punctures on each elytron, six rows between suture and humerus, accessory scutellary row short; punctures large and deeply impressed on anterior portion, smaller and less depressed posteriad especially on elytral declivity; interstices and intervals shiny, slightly raised; intervals with small granules in posterior portion; lateral margin of elytra narrow and elevated, finely irregularly serrated on anterior portion; humeri rounded and moderately prominent. Mesoventrite narrow, anteriorly transversely microstriate, remaining portion irregularly punctate and granulose ( Figure 4 (g)), with pair of transverse anterolateral impressions. Metaventrite ( Figure 4 (f)) longer than combined length of pro- and mesoventrite, with anterior transverse impression, laterally and anteriorly densely punctate and granulate; disc with median moderately deep and moderately broad, almost glabrous longitudinal impression, lateral portion with irregular setiferous granules. Anepisternum 3 narrow, glabrous, with one row of punctures. Hind wings present in all specimens examined.

Legs ( Figures 1 (c), 4(a)) as in A. schoedli , slightly longer than body.

Abdomen. Ventrite 1 with intercoxal process about as long as remaining portion of ventrite 1; lateral portion with granules, mesal portion almost glabrous. Ventrites 2–4 ( Figure 4 (h)) with surface as in ventrite 1; combined length of ventrites 3 and 4 as long as ventrite 1; ventrite 2 of intermediate size; ventrite 5 long, with cordiform setiferous granules. Male sternite IX ( Figure 8 (a)) 430 μm long; apical portion moderately broad, apical margin slightly concave, two short and numerous very short setae laterally; paraprocts moderately long, unequal in length, one almost reaching apical margin; anterior strut long.

Aedeagus ( Figure 8 (b,c)) elongate and slender, 460 µm long. Median lobe long and narrow (80 µm wide), slightly and evenly tapering towards apex; entirely evenly bent ventrad; ventral sac weakly sclerotized, distinctly plicate, reaching apical 0.13; fibula weakly sclerotized, medially distinctly wider, straight; corona inconspicuous. Phallobase asymmetrical, with strongly convex proximal and straight distal margins, strongly sclerotized, about one-quarter of aedeagus length. Parameres long, slender, medially narrowest, slightly inflated near apices, with c.20 moderately short setae at apical third.

Ovipositor ( Figure 8 (d)), total length 525 µm. Stylus long, cylindrical, with about five apical setae. Coxite long and slender; peg-like setae more or less acute, densely dispersed all over distal portion and arranged in cluster at basal portion; margin of coxite moderately densely pubescent mesally; basal portion half as long as distal portion. Valvifer about 1.1 times as long as coxite.

Distribution

Known from a few localities on central and southern Sulawesi ( Figures 18 ; 19 (a,b)).

Etymology

The species is named after the small ethnic group of the Tobada or Bada from Lore Selatan subdistrict of south Central Sulawesi where this species was collected. Tobada is used as noun in apposition.

Comments

This species together with Ancyronyx hafti , A. longiparamerus , A. toraja , A. konjo and A. breviparamerus from Sulawesi and A. buhid from the Philippines share a similar body form, and agree more or less in the arrangement of the four yellow patches on elytra too. All these species possess a median lobe gradually narrowing apicad, without an abruptly widening subapical portion and resemble in the coxite being long and slender, those of the A. patrolus group. The inter-specific differences are mainly in body size, width of pronotum, intensity of the colouration and size of the elytral patches, length of the aedeagus as well as in form, length and setation of the parameres. The most similar species, A hafti differs in: terminal antennomere partly yellowish, maxillary palps light brown and parameres with less than 18 short setae each.

Ancyronyx tobada was exclusively collected from submerged wood in mountain forest brooks of 1–3 m width ( Figure 19 (b)). The collection sites were situated in forests in altitudes between 800 m and 1700 m a.s.l. ( Figure 19 (a)). Ancyronyx breviparamerus occurred syntopically at the highest collection site (type locality).

Figures

Figure 1. Habitus of Ancyronyx species from Sulawesi, (a) Ancyronyx schoedli (total length 1.65 mm), (b) Ancyronyx skalei (total length 1.60 mm), (c) Ancyronyx tobada (total length 1.65 mm), (d) Ancyronyx hafti (total length 1.70 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 8. Ancyronyx tobada from Tentena (Sul10f); (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.

Figure 19. Habitats of Ancyronyx species in Sulawesi, (a) the eastern slopes of the Pegunungan Fennema Mountains from where Ancyronyx breviparamerus, Ancyronyx henningi and Ancyronyx tobada were collected, (b) a small mountain creek in the Pegunungan Fennema Mountains (A), type locality of Ancyronyx breviparamerus and collection site of Ancyronyx tobada, (c) Salu Maiting River in North Toraja, type locality of Ancyronyx longiparamerus and collection site of Ancyronyx