Hedyselmis belatani, Iampor, Fedor Č & Ová, Zuzana Č Iamporová-Za Ť Ovi Č, 2008

Iampor, Fedor Č & Ová, Zuzana Č Iamporová-Za Ť Ovi Č, 2008, A new species of Hedyselmis Hinton and notes on the phylogeny of the genus (Coleoptera: Elmidae), Zootaxa 1781, pp. 55-62 : 56-58

Hedyselmis belatani sp. nov.

Type locality: Malaysia, Kelantan, Hutan Lipur Lata Belatan, 5°38’35”N, 102°35’27”E (ca 35 m a.s.l.), 5 m wide stream, flowing slowly through primary lowland forest.

Material examined: Holotype ɗ Vienna Natural History Museum, Austria: “ Malaysia, Kelantan, Kuala Krai env., stream in Hutan Lipur Lata Belatan, 5°38’35”N, 102°35’27”E, 7.6.2006, ca 35 m a.s.l. Č iampor & Č iamporová-Zaťovičová lgt.”.

Differential diagnosis. Based on several morphological features, it is likely that H. belatani is more closely related to H. gibbosus Jäch & Boukal , from which it differs in: male protibia less regularly excavated; apex of last ventrite not excised; penis slightly longer; fibula with apex rounded; processes of phallobase thiner, more distinctly curved, lateral processes present, apices of admedian processes subtriangular with group of small spines. From H. opis Hinton it differs mainly in body shape, form of median pronotal groove, surface of ventral sclerites, shape of ventrite 5 and male genitalia.

Description. Habitus ( Fig. 1). Body form obovate, length (pronotum + elytra) 4.1 mm, width 2.0 mm. Colour piceous except dark brown tibiae and slightly paler tarsi, antennae, mouth parts and lateral margin of elytra.

Head. Dorsal side densely micropunctured; genae and gula glabrous. Antennal segments 3–10 subequal, scape slightly curved, pedicel ca. 2/3 as long as scape, apical segment acuminate, with apex finely excised. Labrum wider than long, rugose, anterior margin setose; clypeus slightly longer than labrum, densely micropunctured; eyes moderately large, suboval in lateral view, convex in dorsal view, medially with raised, darkened margin.

Thorax. Pronotum almost as long as wide, widest behind middle, strongly convex; lateral margins explanate; anterior margin with two distinct admedian processes; anterior angles produced, rounded; median groove narrow, not reaching pronotal margins; prebasal admedian pits vestigial; surface densely micropunctured, except of almost glabrous prebasal portion. Prosternum densely plicate; sublateral ridges vestigial; prosternal process with margins microreticulate, raised around coxae; posterior margin widely produced. Hypomera wide. Scutellum large, almost rounded, anterior margin straight; surface shiny with few tiny setae and indistinct lateral tubercles. Mesoventrite short and wide; disc with sinuate median carinae; margins around coxae sharply raised. Metaventrite with lateral sides glabrous; disc longitudinally striate; longitudinal suture narrow, well impressed, reaching metaventral margins; admedian prebasal grooves arched around coxae; admedian prebasal tufts of setae present. In Hedyselmis opis and also in Graphelmis Delève , these tufts occur only in males. Thus it is suggested, that the prebasal setal tufts are secondary sexual structures characteristic for males. Elytra about twice as long as pronotum, parallel-sided in about anterior half, then converging toward rounded apices; lateral margins finely serrate, most distinctly explanate in apical third; strial punctures moderately deeply impressed; interval 1 flat, remaining intervals basally at least finely convex, intervals 3 and 4 fused in apical 0.25. Epipleura well developed. Legs glabrous, microreticulate; tibial cleaning fringes indistinct; protibia excavate subapically, with inner surface flattened; remaining tibiae simple, slightly widening towards apex; length of tarsomere 5 equal to combined length of tarsomeres 1–4; tarsi 1, 3, 4 with tufts of moderately long yellow setae; tarsal claws with well developed subbasal tooth.

Abdomen. Admedian keels of ventrite 1 reaching middle, not reaching posterior margin of ventrite; abdominal intercoxal process rounded; discs of ventrites 1–3 plicate, plication more developed on first two segments; ventrites 4–5 smooth; ventrites 2–3 mesally with small microreticulate array; posterior angle of ventrite 4 produced; apex of ventrite 5 rounded, admedially with setal tufts, lateral margin abruptly constricted.

Aedeagus ( Figs 2–4 ). Penis elongate, corona present; fibula with apex rounded, setose; ventral sac well developed, densely setose. Parameres moderately reduced, dorsally situated, shorter than penis, with lateral processes, apices subtriangular with group of small spines on ventral side. Phallobase large, almost as long as penis, with apical „paramere-like“ processes; apical third of processes distinctly narrowed, apex strongly curved toward dorsal side of aedeagus.

Female unknown.

Habitat. The specimen was found on submerged wood in a slowly flowing lowland stream with sandy substrate and large boulders ( Fig. 5 ).

Distribution. So far known only from the type locality ( Fig. 6 ).

Etymology. Named after the type locality “Lata Belatan”.

Phylogenetic analysis. The combined sequence of H. belatani sp. nov. was included in the matrix used in Č iampor & Ribera (2006). The aligned matrix (cox1+cob+rrnL+SSU) had 2,717 characters. Within the whole dataset, there were 648 parsimony informative characters. Heuristic searches resulted in a single most parsimonious tree (consistency index CI=0.54, retention index RI=0.39) ( Fig. 7 ). The sequence of H. belatani was grouped together with both sequences of the H. opis with high support (100% bootstrap, 100—posterior probability values x100 of the Bayesian analysis and 64—Bremer support). The clade Hedyselmis + Graphelmis was also well supported (99% bootstrap, 100—posterior probability values x100 of the Bayesian analysis and 23—Bremer support, Fig. 6 ).

In the Bayesian analyses the sampled ML values reached stationarity at ca. 50,000 generations, but the first 100,000 (i.e. 1,000 trees) were discarded as a burnin. The topology of the 50% majority rule consensus tree was almost identical to that of the parsimony tree, with the same highly supported nodes relating Hedyselmis species and the grouping of Hedyselmis with Graphelmis . The only difference was in grouping Graphelmis obesa Č iampor with Hedyselmis samples.

Figures

FIGURE 5. Type locality of Hedyselmis belatani sp. nov., Malaysia, Kelantan, Kuala Krai env., stream in Hutan Lipur Lata Belatan.

FIGURE 6. Distribution of Hedyselmis species in West Malaysia: Hedyselmis opis; H. gibbosus; H. belatani sp. nov. (Distribution of H. opis and H. gibbosus from Jäch & Boukal 1997).

FIGURE 7. Single most parsimonious tree obtained using the combined dataset. Above branches, posterior probability values (× 100) of the Bayesian analyses (only if> 0.5); below branches, bootstrap (only if more than 50 %) / Bremer support values of the parsimony analyses.

FIGURES 2 – 4. Aedeagus of Hedyselmis belatani sp. nov., 1) ventral view; 2) lateral view; 3) dorsal view. Scale = 0.1 mm.