Cephennomicrus arunensis, Jałoszyński, 2017

Jałoszyński, Paweł, 2017, Ant-like stone beetles on the roof of the world. Cephenniini of Nepal and Bhutan (Coleoptera, Staphylinidae, Scydmaeninae), Zootaxa 4349 (1), pp. 1-120 : 7-8

Cephennomicrus arunensis sp. n.

( Figs 2 , 5, 8–9 , 17 )

Type material. Holotype: NEPAL (Sankhuwasabha District): ♂, " NEPAL, Sanhua Sabha Distr. / Arun Valley bottom between / Hedagna and Num, 950–1000 m / 6.–8.VI.1988 / leg. J. Martens & W. Schawaller " [white, printed] ( SMNS) . Paratypes (9 exx): 2 ♀♀, same data as holotype ; 2 ♂♂, 3 ♀♀, "E NEPAL: KOSI / Val. Arun ss/ Num / 1050 m, 20.IV.84 / Löbl - Smetana " [white, printed] ; 2 ♀♀, same data but 1100 m, 21.IV.84 (paratypes in cPJ, MHNG, SMNS) .

Diagnosis. BL ~ 0.7 mm, head covered with small but distinct, deep and dense punctures; pronotum with very dense, deep and sharply marked punctures, nearly adjacent one to another; elytra with dense but fine and inconspicuous punctures; aedeagus with bell-shaped median complex flanked by darkly sclerotized, broad structures and connected to slender flagellum, in lateral view subapical margin of dorsal wall weakly curved.

Description. Body of male ( Figs 2 , 5 ) stout, with distinct constriction between pronotum and elytra, strongly convex, light brown, covered with slightly lighter vestiture; BL 0.69–0.71 mm (mean 0.70 mm).

Head subtrapezoidal, HL 0.09–0.10 mm (mean 0.10 mm), HW 0.20 mm; vertex and frons confluent, evenly convex; supraantennal tubercles feebly marked; eyes large, strongly convex, coarsely faceted. Punctures on vertex and frons moderately large, deep and distinct, densely and unevenly distributed, separated by spaces 0.5–1 × as wide as diameters of punctures; setae short, barely discernible under magnification 80 ×, sparse and nearly recumbent. Antennae short, slender and compact, with trimerous club, but antennomere IX only slightly larger than VIII, so that club appears dimerous, AnL 0.30 mm; antennomere I 1.5 × as long as broad; II slightly shorter and narrower than I, 1.6 × as long as broad; III distinctly narrower and much shorter than II, slightly broader than long; IV–VII subequal in length and width, each as broad as III but distinctly longer, 1.1–1.2 × as long as broad; VIII minimally larger than VII, 1.2 × as long as broad; slightly larger than VIII, 1.1 × as long as broad; X much broader and longer than IX, about as long as broad; XI as broad as X but slightly longer, with distinct subapical constriction.

Pronotum in dorsal view nearly subquadrate, broadest near middle, length 0.23 mm, width 0.29–0.30 mm (mean 0.30 mm); anterior margin weakly arcuate; lateral margins indistinctly microserrate, strongly rounded in anterior fourth, then weakly rounded up to slightly obtuse-angled hind corners; posterior margin nearly straight; base of pronotum with two pairs of small but distinct lateral antebasal pits. Pronotal disc covered with moderately large, deep and very distinct punctures nearly adjacent one to another; setae very short, sparse and nearly recumbent, additionally pronotum with two pairs of long and strongly erect setae: at anterior third of lateral margin and near hind corner.

Elytra oval, stout, broadest distinctly anterior to middle, length 0.38–0.39 mm (mean 0.38 mm), width 0.35 mm, EI 1.07–1.11. Humeral calli small but well marked, mesally delimited by oblique, moderately deep, relatively narrow basal impression; apices of elytra separately rounded. Punctures very fine, shallow, very dense; setae extremely short, barely noticeable under magnification 40 ×, nearly recumbent, additionally each elytron bears a single long seta located near humeral denticle.

Hind wings not studied.

Aedeagus ( Figs 8–9 ) thin-walled, AeL 0.11 mm, with subtrapezoidal apex; internal armature composed of slender flagellum connected to small, bell-shaped structure near middle of median lobe and surrounded at each side by short and broad dark sclerites; parameres slender, each with two apical setae.

Female. Externally indistinguishable from male; BL 0.70–0.71 mm (mean 0.70 mm); HL 0.10 mm, HW 0.20– 0.21 mm (mean 0,20 mm), AnL 0.28 mm; PL 0.23–0.24 mm (mean 0.23 mm), PW 0.30 mm; EL 0.38 mm, EW 0.33–0.35 mm (mean 0.35 mm), EI 1.07–1.15.

Distribution ( Fig. 17 ). Eastern Nepal.

Etymology. Locotypical, after Arun Valley, the type locality.

Remarks. Cephennomicrus arunensis is the smallest species of this genus known to occur in Nepal. It resembles C. acupunctatus in conspicuous pronotal punctures; the latter species differs in a larger body (> 0.8 mm vs. ~ 0.7 mm in C. arunensis ), proportions of body parts and aedeagal structures.

Figures

FIGURES 2 – 4. Dorsal habitus of Cephennomicrus arunensis sp. n. (2), Cm. acupunctatus sp. n. (3), and Cm. taplejungensis sp. n. (4).

FIGURES 5 – 13. Body outline (5 – 7) and aedeagus in ventral (8, 10, 12) and lateral (9, 11, 13) views. Cephennomicrus arunensis sp. n. (5, 8 – 9), Cm. acupunctatus sp. n. (6, 10 – 11), and Cm. taplejungensis sp. n. (7, 12 – 13).

FIGURES 17 – 18. Distribution of Cephennomicrus arunensis sp. n. (17, circle), Cm. acupunctatus sp. n. (17, circle), Cm. taplejungensis sp. n. (17, triangle) and Hlavaciellus primitivus sp. n. (18, circle).