Siamites complicatus Jałoszyński, 2013, sp. n.
Creators: name: Jałoszyński, Paweł
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Siamites
Siamites complicatus

description: Siamites complicatus sp. n.
(Figs. 1–12)
Type material. Holotype: THAILAND (Krabi Prov.): ♂, two labels: " THAILAND: Krabi province / 10 km N Krabi. Pitfalls / 8°09'N, 98°50'E / October 1991, O. Martin leg. / Zoologisk Museum, København" [white, printed]; " SIAMITES / complicatus m. / det. P. Jałoszyński, '13 / HOLOTYPUS " [red, printed] (ZMUC). Paratypes (2 ♂♂): same data as holotype, except for yellow " paratypus " label (ZMUC, cPJ).
Diagnosis. Aedeagus with a pair of corkscrew-like lateral apical sclerites.
Description. Body of male (Figs. 1–2) strongly convex and relatively slender, brown with slightly lighter legs and palps, covered with yellowish vestiture. BL 1.10–1.13 mm.
Head (Figs. 3–4, 6–7) broadest at large, strongly convex and coarsely faceted eyes, HL 0.18–0.20 mm, HW 0.23–0.25 mm; 'neck region' hidden inside prothorax with dorsal median expansion adjacent to posterior part of vertex; tempora in dorsal view distinctly shorter than eyes; vertex slightly impressed, strongly transverse; frons confluent with vertex, flattened in middle and rapidly declining anterad; supraantennal tubercles weakly marked. Vestiture of head dorsum (Fig. 6) composed of four rosettes of dense bristles forming a transverse arc on vertex; long and sparse suberect to erect bristles on posterior part of frons; thin, sparse and suberect setae on anterior part of frons; and long, erect and curved bristles on tempora. Punctures on frons and vertex unremarkable, fine and sparse. Antennae (Figs. 1–2) slightly longer than head and pronotum, AnL 0.48; scape and pedicel strongly elongate; antennomere III about as long as broad; antennomeres IV–VII each slightly longer than broad; VIII–X each strongly transverse; XI distinctly narrower than X, slightly longer than broad.
Prothorax (Figs. 1–2, 8) elongate, with subrectangular pronotum only slightly narrowing anterad and with well-marked anterior and posterior corners, broadest in posterior fourth; PL 0.29–0.30 mm, PW 0.25 mm. Anterior margin weakly arcuate; anterior pronotal angles slightly obtuse; lateral margins rounded; posterior angles slightly obtuse; posterior margin weakly arcuate; pronotum with distinct carinate lateral edges in posterior half and arcuate transverse ante-basal groove deepened at each end and indistinctly shallower in middle. Vestiture of pronotum composed of sparse and suberect thin setae distributed on dorsum and thick erect bristles on sides; prosternum (Fig. 8) with a transverse row of eight bunches of dense bristles along anterior margin. Punctures on pronotum fine and sparse, unremarkable.
Elytra (Figs. 1–2) more convex than pronotum, oval, broadest distinctly anterior to middle; EL 0.63 mm, EW 0.45–0.46 mm, EI 1.35–1.39; humeral calli weakly marked, each with indistinct humeral carina extending to 1/4 of elytral length; basal foveae small but located in large and deep basal impression; apices of elytra separately rounded. Vestiture uniform, composed of short, moderately dense and suberect setae; punctures fine and sparse. Hind wings well developed.
Mesoventrite (Fig. 9) with large asetose impressions, strongly projecting latero-ventrally mesocoxal projections and moderately expanding ventrally keel-like mesoventral intercoxal process; vestiture of ventrite with bunches of dense bristles directed laterally along anterior margin of mesocoxal cavities, several bristles directed posteriorly on antero-mesal margin of mesocoxal cavities; dense setae directed posteriorly on mesoventral intercoxal process; and lateral bristles mixed with thin setae on mesanepisterna.
Metaventrite (Fig. 9) with several rosettes of dense bristles along posterior margin of mesocoxal cavities.
Each abdominal sternite (Fig. 9; only abdominal ventrites I–III shown) with several bunches of dense setae along posterior margin.
Legs moderately long and slender; mesocoxae (Fig. 9) with two bunches of dense bristles on posterior margin.
Aedeagus (Figs. 10–12) stout and small; AeL 0.13 mm; median lobe divided by transverse fold into basal and apical parts; apical part with lateral sclerites each forming a spiral with tip of sclerite directed mesad; internal sclerotization complex, in ventral view with large subtriangular and dark structure in middle and subconical apex of copulatory piece projecting distally; parameres short but slender, each with three apical setae.
Female. Unknown.
Distribution. Southern Thailand, Krabi Prov. (Fig. 5).
Etymology. The name complicatus refers to the structure of the aedeagus, far more complex than that of S. loebli.
Remarks. Siamites complicatus clearly differs from S. loebli not only in the aedeagus with lateral apical corkscrew-like sclerites (absent in S. loebli) but also in distinctly stouter body, with the elytral index 1.35–1.39, while males of S. loebli have more slender elytra, with EI = 1.44–1.52 (and females 1.50–1.55). To date, Siamites was known only from two localities in Central Thailand: the Kaeng Krachan and Khao Yai National Parks (Fig. 5). The discovery of the new species in the Krabi Province extends the range of Siamites nearly 600 km southward.
description: Published as part of Jałoszyński, Paweł, 2013, A new species of Siamites Franz (Coleoptera, Staphylinidae, Scydmaeninae) from Thailand, pp. 385-390 in Zootaxa 3734 (3) on pages 386-389, DOI: 10.11646/zootaxa.3734.3.8, http://zenodo.org/record/216445