Tricosa uniseriata Sittichaya & Cognato, 2023

Sittichaya, Wisut & Cognato, Anthony I., 2023, Tricosa uniseriata, a new species of xyleborine ambrosia beetle from Thailand (Coleoptera, Curculionidae, Scolytinae, Xyleborini), ZooKeys 1153, pp. 97-103 : 97

Tricosa uniseriata Sittichaya & Cognato sp. nov.

Fig. 1A-F

Type material.

Holotype, female, Thailand, Narathiwat Province, Hala-Bala Wildlife Sanctuary, 5°48'02.4"N, 101°49'58.2"E, lowland tropical rainforest, 140 m a.s.l., 12.x.2021, ex. small branch of Artocarpus integer (W. Sittichaya) (NHMW, Naturhistorisches Museum Wien, Wien).

Similar species.

T. hipparion Smith, Beaver & Cognato, 2022.

Diagnosis.

This species is distinguished by its stoutness: 2.35 mm long, 2.40 × as long as wide. The combination of the following characters is diagnostic: lateral margin of elytra feebly broadened apically; elytral disc convex; discal striae and interstriae uniseriate punctate; stria weakly impressed and interstriae elevated; anterior margin of pronotum with six moderate serrations.

Description

(female). 2.35 mm long, 2.40 × as long as wide. Body dark brown, except appendages yellowish brown. Body more robust, less elongate. Head: epistoma entire, transverse, lined with a row of short, hair-like setae. Frons flat from epistoma to middle level of eye, then slightly convex upward to vertex; lower portion of surface at medial line shagreened, subshining; sides of medial line glabrous, strongly shinning; upper portion shagreened, subshining; frons with widely separated, small granules, with each granule decorated with long, fine, hair-like setae. Eyes weakly emarginate above level of antennal insertion; upper portion of eyes slightly smaller than lower part. Submentum slightly impressed below genae, widely triangular at base. Antennal club type 3 ( Hulcr et al. 2007; Smith et al. 2020); scape regularly thick, as long as club. Antennal funicle four-segmented; first segment longest and other segments approximately equal in length. Pedicel shorter than funicle. Club flattened, approximately circular (type 3) ( Hulcr et al. 2007; Smith et al. 2020); segment 1 corneous, transverse on anterior face, occupying basal ~1/3; segment 2 slightly concave, corneous and corneous line very narrow; segments 1 and 2 present on posterior face.

Pronotum: 1.0 × as long as wide; elongate and parallel sided in dorsal view, type 7 ( Hulcr et al. 2007; Smith et al. 2020); sides parallel in basal 2/3, rounded anteriorly; anterior margin with a row of six serrations. In lateral view, elongate, disc longer than anterior slope, type 7, summit low, on apical 2/5. Surface alutaceous, anterior 1/2 asperate; asperities robust, close together, arranged in concentric arcs from midpoint of pronotum to anterior and anterolateral areas; disc evenly punctate, punctures moderate in size, round and deep, sparse and separated by glabrous, shinning areas 3-5 × the size of puncture, each puncture with short, erect, hair-like seta, some longer hair-like setae at margins. Lateral margins obliquely costate. Base transverse, posterior angles acutely rounded. Scutellum: small, narrow, linguiform, flush with elytra, shiny. Elytra: 1.36 × as long as wide, 1.44 × as long as pronotum. Base transverse, margins oblique; humeral angles rounded. Sides subparallel, slightly broader from base to apical 3/4, then attenuate at apical 1/4, apex attenuate, broadly rounded. Disc convex, surface smooth, shinning, striae and interstriae uniseriate. Striae feebly impressed, punctate, punctures round, broad, and shallow, separated by 1/2 the width of a puncture, each puncture with a short, fine, inconspicuous, hair-like seta. Interstriae feebly elevated, elevation more evident apically; interstriae minutely uniseriate punctate-granulate, widely spaced, near elytral base with fine punctures and small granules on apical 1/2, granules slightly increasing in size apically; each puncture or granule with a very long, hair-like seta. Declivity occupying ~1/3 of elytra, gradual, face feebly convex, subshining; striae feebly impressed, punctate, punctures similar in size with those on the disc, each with short, fine, hair-like seta; interstriae feebly elevated, with small granules, granule apices curved ventrad, each granule with very long hair-like seta; setae on declivity twice as long as those of disc. Posterolateral margins rounded and granulate. Legs: procoxae contiguous, prosternal posterocoxal piece conical, slightly inflated. Protibiae distinctly triangular, broadest at apical 1/3, posterior face flat, unarmed; outer margin armed with five large denticles at apical 1/3. Meso- and metatibiae obliquely triangular, flattened, posterior face unarmed; outer margin armed with 6 and 10 moderately socketed denticles.

Male. Unknown.

Etymology.

L. uniseriata: uni - = one; series = row. Refers to the arrangement of strial and interstrial punctures in one line. A variable adjective.

Distribution.

Thailand (Narathiwat Province).

Host plants.

The holotype was collected from a small branch of Artocarpus integer (Thunb.) Merr. ( Moraceae ).

Figures

Figure 1. Tricosa uniseriata sp. nov. holotype female A dorsal view B ventro-lateral view C posterolateral view D front E declivity F antenna.