Octomeristes pusillus Liu & Beaver, gen. et sp. nov.

urn:lsid:zoobank.org:act: 49448B21-C6F2-4868-A919-F350D93E89B8

Figs 1–3

Etymology

The species name refers to the diminutive size of the beetle, which is one of the smallest species of Bostrichidae.

Type material

Holotype

THAILAND: 1 ♀ (NHML [E]/ 2013-96), “ Chiang Mai, Doi Pui, Khun Chang Highland Research Station. c. 1300m, ex Litchi chinensis, 18.v.2013 (S. Sanguansub)”.

Allotype

THAILAND: 1 ³ (NHML [E]/ 2013-96), same data as for the holotype.

Paratypes

THAILAND: 1 ♀, 1 ³ (RAB), same data as for the holotype; 2 ♀♀ (LYL), same data as for the holotype;

THAILAND: 1 ³ (KSU), same data as for the holotype; 1 ³ (damaged, QSBG), “ Nan, Doi Phu Kha NP, Office 14, 19°12.488'N, 101°4.907'E, 1375m, pan trap, 2–3.xii.2007 (Charoen & Nikhom)”.

Description

Body 1.9–2.1 mm long, about 2.7 times (male) or 2.8 times (female) as long as wide, cylindrical; piceous, shining, labrum brown, palps, first five antennomeres and legs pale yellowish or yellowishbrown, except for blackish anterior tibiae. Frons convex, almost smooth and finely punctured in middle, towards sides a series of long, concentrically arranged, fine rugae extending to vertex (Fig. 1B),

th E–F: I to V are the 1 st to 5 ventrites, O is the ovipositor.). scattered, fine, upwardly-directed hairs denser, coarser and more erect near eyes and antennal insertions. Female with one extremely long hair on each side inserted close to eye. Fronto-clypeal suture indistinct at sides, impressed in middle. Clypeus slightly convex, granulate-punctate, depressed along posterior margin in median half, anterior margin with very short median lobe, weakly concave anteriorly, a small emargination on each side of lobe. Labrum transverse, a fringe of yellowish hairs along anterior margin. Antennae with a few erect hairs on inner and outer margins of first two antennomeres, a single hair on each side of antennomeres 3–5, antennomeres 6 and 7 subtriangular, subequal, eighth antennomere 1.8–1.9 times longer than antennomere 7, elongate-oval (Fig. 1 B–C).

Pronotum 1.1–1.2 times wider than long, widest about one-third from base, anterior angles with a strong, upcurved tooth on margin, semicircular area above anterior margin with scattered, fine punctures; sides of pronotum broadly rounded, converging more strongly anteriorly, posterior angles broadly rounded, without lateral carina, postero-lateral area with fine rugulosities; anterior slope with 3–4 large upcurved teeth antero-laterally on each side, remaining teeth gradually reduced in size towards summit, and arranged approximately in arcs; discal surface smoooth and very indistinctly punctate on basal half, postero-lateral areas with small, widely-spaced, slightly elongate rugulosities. Anterior slope with short, semi-erect hairs between teeth, disc glabrous, small, recumbent hairs on sides.

Elytra about 1.8–1.9 times longer than wide, slightly more elongate in female than male, 2.2–2.3 times longer than pronotum, subequal to pronotum in width, sides parallel in female, slightly widened posteriorly in male; basal margin slightly convex, raised between humerus and scutellum, elytral disc slightly depressed behind margin, basal two-thirds of disc extremely finely, sparsely punctured; posterior part of disc with three pairs of costae, slightly converging towards suture, costae and grooves between them with larger and deeper punctures, each costa ending in a small tooth with a rounded tip at upper margin of elytral declivity, tooth projecting slightly over declivity (Figs 1A; 2A, C); declivity weakly convex, glabrous, rather sparsely, shallowly, coarsely punctured, punctures decreasing in size and density toward apex; suture gradually more strongly raised from one-third from base, most strongly raised in middle of declivity; postero-lateral margin raised; elytral apex broadly rounded with a short, rounded projection on either side, a V-shaped emargination at the suture, and a shallow arcuate emargination lateral to apex (Figs 2C; 3B).

Legs subequal in length, tibiae expanded towards apex, a fringe of short hairs on outer margin, hairs shorter on protibiae; anterior surface of protibia flattened, matt, surface slightly roughened; apical spine of protibia longer in male than female. Inner face of female protibia with dense fine hairs (Fig. 2D). Protarsi of female with numerous, long, curling hairs on ventral side; male protarsi with shorter and straighter hairs (Figs 2D; 3D).

Female abdomen with first ventrite about 1.5 times as long as second, 3 rd ventrite about as long as 1 st and extending over 4 th, concealing it, its apical third curved ventrally, apical margin thickened to form a projecting median lobe, and a larger rounded lobe at each side, thinner and depressed between these thickened areas. On dorsal surface of depressed areas on apex of 3 rd ventrite a pair of dorsally projecting spines, separated by width of median lobe. Apical margin of 4 th ventrite thickened to form a projecting median lobe, a pair of small spines extending posteriorly from each side of lobe. Apical margin of 5 th ventrite thickened at sides, a bunch of coarse hairs extending posteriorly from middle of apical margin (Figs 2B, E–F).

Male abdomen with first ventrite about 1.5 times as long as 2 nd; 2 nd, 3 rd and 4 th subequal, 5th with welldeveloped pleural pieces. Surface of abdominal ventrites smooth, shining with sparse, recumbent hairs, a fringe of hairs on apical margin of 5 th ventrite (Fig. 3C).

Distribution

Northern Thailand.