Trurlia acutangula, ski, 2011

ski, P. Jałoszy, 2011, Four New Species Of Trurlia Jałoszy Ski From Sumatra And Borneo (Coleoptera: Staphylinidae: Scydmaeninae), Raffles Bulletin of Zoology 59 (1), pp. 69-75 : 69-71

Trurlia acutangula , new species

( Figs. 1a , 2a , 3a, b )

Material examined. – Holotype. Male, two labels: “ SUMATRA: Aceh # 25a \ Mt Leuser NP, 300- \ 500 m, Ketambe, 23- \ 30.XI.1989, Löbl \ Agosti, Burckhardt” [white, printed], “ TRURLIA \ acutangula m. \ P. JAŁOSZY SKI, ‘2010 \ HOLOTYPUS ” [red, printed] ( MHNG). Paratypes. 1 male, 9 females, same data as holotype ( MHNG, PCPJ).

Diagnosis. – Anterior part of frons and clypeus with fine transverse wrinkles; basic vestiture of pronotal disc well visible under magnification 40×; front angles of pronotum in males strongly and in females slightly but distinctly projecting anterad; pronotum in posterior half barely noticeably narrowing toward base; ante-basal pronotal groove arcuate; humeral carinae shorter than half length of elytra; aedeagus in ventral view with blunt, subtriangular apex and simple (i.e., not narrowed) apices of parameres.

Male. – Body ( Figs. 1a , 2a ) strongly convex, oval, with distinct but shallow constriction between pronotum and elytra; pigmentation chestnut-brown with slightly lighter antennae, palps and legs, vestiture light brown. Body length 1.14–1.20 mm.

Head moderately large in relation to pronotum, length 0.13 mm, width 0.30 mm, vertex and posterior part of frons confluent and convex, evenly and densely covered with large, elongate, sharply marked and deep punctures separated by spaces half as long as puncture diameters, anterior part of frons and clypeus with smaller punctures and fine transverse and oblique wrinkles; supraantennal tubercles small and weakly raised; eyes large and strongly convex, coarsely faceted; antennal club large and oval, length of antennae 0.35 mm.

Pronotum broadest near middle, barely noticeably narrowing toward base, in strictly dorsal view trapezoidal with front angles strongly protruding anterad and their frontomesal surfaces flattened and expanded; length 0.38-0.40 mm, width 0.55-0.56 mm; lateral margins microserrate, slightly concave just behind front angles, rounded in middle and nearly straight in posterior fifth; hind angles nearly right and blunt; posterior margin with three shallow emarginations; internal ante-basal foveae small but distinct, connected by sharply marked, arcuate groove; oval lateromedian foveae located just posterior to middle, each with frontomesal fringe of long setae. Surface of disc densely covered with large, elongate, sharply marked and deep punctures separated by spaces as long as half puncture diameters; basic setae very short, sparse and recumbent but well visible, additionally pronotum with several pairs of very long, strongly curved and suberect macrosetae ( Fig. 2a ).

Elytra oval and very short, broadest distinctly anterior to middle, length 0.64–0.68 mm, width 0.63–0.65 mm, elytral index 1.02–1.04; humeral carinae slightly divergent caudad, as long as 0.48× of elytral width; surface of elytra covered with punctures much smaller, shallower and sparser than those on pronotum, separated by spaces 2–3× as long as puncture diameters; each elytron with about 14 long, strongly curved and suberect macrosetae ( Fig. 2a ). Hind wings fully developed.

Aedeagus ( Figs. 3a, b ) 0.26 mm in length, in ventral view strongly narrowing toward blunt, subtriangular apex; internal armature simple and lightly sclerotized, composed of median tubular structure located in distal half of aedeagus; parameres not reaching apex of median lobe, with simple apices, each with three setae: long apical and short median subapical seta inserted close to each other and long proximal subapical seta.

Female. – Slightly larger and stouter than male, with less protruding front angles of pronotum and lateral margins behind front angles rounded; body length 1.18–1.28 mm (mean 1.24 mm); length of head 0.13–0.16 mm (mean 0.15 mm), width 0.31–0.34 mm (mean 0.32 mm); length of antennae 0.35–0.39 mm (mean 0.38 mm); length of pronotum 0.38–0.43 mm (mean 0.41 mm), width 0.60–0.63 mm (mean 0.61 mm); length of elytra 0.65–0.70 mm (mean 0.68 mm), width 0.65–0.68 mm (mean 0.67 mm), elytral index 1.00–1.04.

Etymology. – The Latin adjective acutangulus (“sharpangled”) refers to the projected front angles of the pronotum in this species.

Distribution. – Sumatra ( Indonesia: province Aceh).

Remarks. – The projected anteriorly and broadened frontomesally front angles of the pronotum, remotely resembling a similar modification common in Cryptophagidae , are very unusual character in the Cephenniini . In most taxa belonging in this tribe the front angles of the pronotum are blunt and not visible or barely visible in dorsal view. A similar character state can be seen in T. semengohensis described below, but in males of the latter species the apices of front angles are distinctly less projected and broadened than those in females of T. acutangula .

Figures

Fig. 1. Dorsal habitus of holotype males. Trurlia acutangula new species (a), Trurlia biarcuata new species (b), Trurlia constricta new species (c), Trurlia semengohensis new species (d). Scale bars = 0.2 mm.

Fig. 2. Simplified outline of left body half in dorsal view and distribution of macrosetae. Trurlia acutangula new species (a), Trurlia biarcuata new species (b), Trurlia constricta new species (c), Trurlia semengohensis new species (d). Scale bars = 0.2 mm.

Fig. 3. Aedeagus in ventral (a, c) and lateral (b, d) views. Trurlia acutangula new species (a, b), Trurlia biarcuata new species (c, d). Scale bar = 0.1 mm.