Arixyleborus liratus Sittichaya, Beaver & Smith, 2024

Sittichaya, Wisut, Beaver, Roger A. & Smith, Sarah M., 2024, Four new species of Arixyleborus Hopkins, 1915, ambrosia beetles from Thailand (Coleoptera: Curculionidae: Scolytinae: Xyleborini), Zootaxa 5446 (1), pp. 65-76 : 68-70

Arixyleborus liratus Sittichaya, Beaver & Smith sp. nov.

http://zoobank.org/ urn:lsid:zoobank.org:act:57FE3DEA-04CF-4378-BF2D-7F5BEE3C141E

( Fig. 2 )

Type material. Holotype, female: THAILAND: Narathiwat Province, Hala-Bala Wildlife Sanctuary , 5°48’02.4”N, 101°49’58.2”E, 140m, lowland tropical rainforest, ethanol baited trap, 01.iv.15, W. Sittichaya ( NHMW) ; Paratypes, female, same as holotype (9) (1, MSUC; 1, THNHM; 7, WSTC); Malaysia, Sabah, Sipitang, Mendolong , 8.xii.1987, S. Adebratt (2) (2, RABC), same collection data except; 20.iii.1989 (2) (2, RABC) .

Diagnosis. 1.88–2.00 mm long (mean 1.91, n = 10); 2.44–2.57× as long as wide. This species is distinguished by the antennal club wider than long; pronotum type 7 in dorsal view, evenly rounded anteriorly, anterior margin without serrations; elytral disc with striae impressed and interstriae raised from close to base; declivity angularly separated from disc, apex angularly rounded; posterolateral margin acute with a series of small teeth; protibiae with posterior surface inflated, tuberculate. This species is similar to A. mediosectus (Eggers) but is distinguished by ( A. liratus given first): body distinctly stouter, 2.44–2.57× as long as wide vs body elongate 2.86−3.33× as long as wide; pronotum 1.1‒1.3× as long as wide vs pronotum 1.3‒1.4× as long as wide; elytral disc with striae impressed and interstriae raised from basal 1/5 vs elytral disc almost flat, striae impressed and interstriae raised only in apical 1/5; declivital interstriae with a row of strong, rounded granules vs declivital interstriae with minute granules.

Description (female). 1.88–2.00 mm long (mean 1.91, n = 10); 2.44–2.57× as long as wide. Body tending to be bicolored, head, pronotum and declivity dark brown to black; elytral disc and appendages paler brown or reddish brown to reddish black. Head. Epistoma entire, transverse, with a row of hair-like setae. Frons feebly convex from epistoma to upper level of eyes, without distinct vertical medial line; surface alutaceous, shiny, sparsely granulate punctate; minutely granulate above epistoma, finely, shallowly punctate near upper level of eyes and laterally near gena; each granule and puncture with a fine hair-like seta. Eye deeply, triangularly emarginate above level of antennal insertion, upper and lower parts of eyes approximately equal in size. Submentum strongly impressed, triangular. Antenna with scape thick, slightly longer than club. Pedicel as long as funicle. Funicle 4-segmented, segment 1 shorter than pedicel. Club slightly wider than long (8/7), rounded, type 1, obliquely truncate, sutures not visible on posterior face; segment 1 corneous, anterior margin completely costate, concave on anterior face, occupying approximately basal half; segment 2 narrow, pubescent with narrow corneous part, visible on anterior face only. Pronotum. 1.1‒1.3× as long as wide. In dorsal view, elongate, sides parallel in basal 3/4, type 7; anterior margin rounded without serrations. In lateral view, elongate with disc much longer than anterior slope, type 8, summit low. Anterior slope finely asperate, asperities low, densely placed, becoming lower towards summit. Disc alutaceous, subshiny, with moderately dense, minute, shallow punctures, each puncture bearing a very short, fine, hairlike seta directed anteriorly. Lateral margins obliquely costate. Base weakly concave. Elytra. 1.17‒1.35× as long as wide, 1.0‒1.1× longer than pronotum. Scutellum moderately sized, linguiform, distinctly raised, surface rugulose, subshiny, impunctate. Elytra opaque, dull, except interstriae 2–4 shiny on basal half of the disc. Elytral bases weakly sinuate, edge costate, feebly elevated, margin with a row of minute granules, a semicircular area around scutellum distinctly impressed, humeral angles rounded. Sides straight from base to apical 1/2 of declivity then angularly rounded, apex slightly projecting at suture. Disc twice as long as declivity, distinctly angularly separated from it; basal part of disc smooth, weakly shining on interstriae, striae weakly impressed close to base, deepening posteriorly, each with a row of closely-placed punctures increasing in size posteriorly; interstriae flat at base, becoming narrower and more convex posteriorly, rather coarsely rugose-granulate before declivity, finely, irregularly punctured. Declivity steep, weakly convex with striae weakly impressed on upper part, the punctures smaller than on posterior part of disc, and decreasing in size towards apex, striae 1‒3 extending to elytral apex, striae 4 and 5 convergent, extending about halfway down declivity, striae 6 curved around lateral margin of declivity to meet striae 3 near apex; interstriae coarsely, uniseriate granulate, granules decreasing in size posteriorly, sutural interstriae raised on lower half of declivity, and with more closely placed granules; interstriae on disc with very short, semi-recumbent, hairlike setae; setae longer and coarser on declivity, each tapering to a fine point, uniseriate except on declivital interstriae 1 where forming 2‒3 irregular rows; striae with short, appressed hairs only on declivity; posterolateral margin acute from apex to interstriae 7, with a series of small teeth. Legs. Protibiae slender, slightly broadened distally; posterior face inflated, rather robustly tuberculate; outer margin with six socketed denticles in apical 2/3. Mesotibiae and metatibiae flattened, outer margin evenly rounded, with nine socketed denticles, posterior face unarmed.

Male. Unknown.

Etymology: Latin adjective, liratus = having ridges, referring to the ridged interstriae of the elytra.

Distribution: MALAYSIA: Sabah; Thailand: Narathiwat Province.

Figures

FIGURE 2. Arixyleborus liratus sp. nov. holotype female A) dorsal view B) lateral view C) postero-lateral view D) frons E) antenna.