Intybia guttata Pascoe, 1866

Tshernyshev, Sergei E., 2016, Taxonomic revision of Intybia Pascoe, 1886 species (Coleoptera, Malachiidae) of Thailand and Philippines, Zootaxa 4147 (2), pp. 101-123 : 103-105

Intybia guttata Pascoe, 1866

( Figs 1–5 )

Material examined. Holotype, female, Indonesia, Bacan Islands ( Fig. 4 ).

Description. Female ( Figs 1, 2 ). Body slightly elongate, ovoid, expanded posteriorly just behind humeri.

Body dark brown, except for yellow tarsi and lateral sides of 1st–7th antennal segments and white spots in elytral disc. Each elytron with three white spots, one, wide, oval, transverse, in basal half above the middle, not reaching suture or external side but disposed closer to outer side; two spots in apical half below the middle, one, triangular, near suture, second, round near external margin, both spots disposed separate from margins and each other. Underside of body dark brown; legs dark brown with yellow tarsi except for claw segments. Surface evenly covered with short semi-erect white pubescence and sparse erect hairs. Vesicles yellow, thoracic mesepimera brown.

Head ( Fig. 3 ) slightly wider than pronotum, not elongated, eyes small, round, protruding, but not stretched, frons flat; interocular area with distinct thin longitudinal carina in the middle, genae impressed and oblique; clypeus extremely narrow due to very closely settled antennae, not elongate, transverse, straight; labrum not elongated, transverse; palpi simple with apical segment slightly enlarged, subcylindrical, narrowed posteriorly and cut at the tip, intermediate segments subtriangular, short and transverse; surface of head densely and coarsely punctured, with weak microsculpture, light pubescence dense, short and adpressed.

Antennae filiform ( Fig. 2 ), 1.4 mm long, reaching the basal quarter of the elytra; segment 1 slightly enlarged, subtriangular, slightly angulate at the outer apical angle, segment 2 small, round-oval, 3rd segment elongated, enlarged and terete; 4th segment short and cylindrical, similar in length to 5th or 6th segment, 7–11th segments elongated and cylindrical, apical segment somewhat longer than previous, evenly narrowed and pointed at apex; surface evenly covered with short, light pubescence and sparse, semi-erect long light hairs on outer sides of antennomeres.

Pronotum not elongated, transversal, somewhat barrel-shaped with not marginate lateral sides, each with small smoothed denticle in middle; slightly narrowed from middle to base, anterior and posterior sides marginate and straight, disc convex anteriorly and narrowly depressed at base; surface dull, densely punctured with distinct microsculpture, surface densely covered with fine, short, white adpressed hairs.

Scutellum small, narrow, rectangular, transversal, with straight apical margin, almost completely covered by pronotum, sparsely punctured, shiny, sparsely pubescent with white hairs.

Elytra oval, distinctly widened just behind the humeri, and evenly rounded posteriorly, at base slightly wider than pronotum; humeri distinct, protruding; suture slightly marginate and elevate, more distinctly at basal quarter, which is impressed, and posterior part convex; surface dull, with dense and coarse punctures and distinct microsculpture, evenly covered with white double pubescence—short adpressed and strong erect hairs.

Hind wings indistinct.

Legs thin; posterior femora not reaching elytral apices; all tibiae thin, straight, femora narrow, slightly compressed, not curved; all tarsi 5-segmented, 1st–4th segments short and compressed, claw segment depressed and largest, wide in all legs and equal to 1st–3rd segments; claws very small, thin, narrow and sharp, with small membrane at base.

Ventral body surface densely punctured, dull, evenly covered with sparse fine, depressed dark pubescence. Metathorax slightly swollen, simple, lacking appendage.

Length 2.5 mm, width (at elytral base) 0.7 mm.

Distribution. The species remains known only from its type locality, Bacan Islands, Indonesia ( Fig. 5 ).

Comments. According to Zoological Nomenclature, characters of I. guttata Pascoe defining the genus Intybia Pacoe should be precisely given. Female holotype of the species complicates this problem because no one male character traditionally used for generic identification. Thus, it is expected that the male of I. guttata Pascoe lacks a tarsal comb in anterior legs, and therefore cannot be considered as Dicranolaius Champion species. Complex of characters, such as not elongate head and simple, not stretched eyes allow one to separate this species from the genus Troglointybia Tshernyshev. Thus, I. guttata Pascoe belongs to a group of species with the following characters: head elongate in male and/or in female; eyes round, simple, protruding, not stretched; palpae with enlarged apical segment and small triangular intermediate ones; genae impressed and oblique for clear placement of enlarged 1st antennomere; interocular area of head flat, lacking sculpture but possessing longitudinal thin carina in the middle; pronotum and elytra depressed at base and convex at distal parts; tarsi short, 1st–4th segment compressed, claw segment depressed, wide, equal in length to 1st–3rd segments. This complex of characters is untypical for all representatives of Intybia sensu lato, and good, for example, for I. quadristrigatus (Champion, 1921) comb.n. or I. semperi (Champion, 1921) discussed below, but reflects the main difference in simple legs, lacking tarsal comb and unsculptured head. More detail results could be gained after investigation of male if it will be found in Indonesian islands.

Figures

FIGURES 1 – 5. Intybia guttata Pascoe, 1866, holotype, female, dorsal view (1); lateral view (2); head (3); original labels (4); distribution map (5). Scale bar 0.5 mm.