Cryptoxyleborus brevicauda Sittichaya & Beaver, 2024

Sittichaya, Wisut & Beaver, Roger A., 2024, Cryptoxyleborus brevicauda, a new species of xyleborine ambrosia beetle from Thailand (Coleoptera: Curculionidae: Scolytinae: Xyleborini), Zootaxa 5506 (3), pp. 396-401 : 398

Cryptoxyleborus brevicauda Sittichaya & Beaver sp. nov.

( Fig. 1 )

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.vii.2014, W. Sittichaya (deposited in Naturhistorisches Museum Wien,Vienna, Austria; NHMW) ; Paratype, female, same as holotype, except 01.iii.2015 (1) (deposited in private collection of Wisut Sittichaya, Songkhla, Thailand ; WSTC) .

Diagnosis: 2.1–2.18 mm long (mean 2.14, n = 2); Pronotal anterior margin feebly protruding and armed by two small asperities, body robust and stout, 3.00–3.03× as long as wide, elytra 1.86× as long as wide, 1.60–1.63× as long as pronotum, without mycangial opening, interstriae unarmed by tubercles, apex strongly attenuate. This species resembles C. confusus Browne (holotype and paratype in Natural History Museum, London, and two specimens in R.A. Beaver’s collection determined by F.G. Browne examined), but is distinguished by the following characters ( C. brevicauda given first): smaller body size 2.10–2.18 mm long vs. larger body size 2.5–2.6 mm long; slightly more elongate body form, 3.00–3.03× as long as wide vs. slightly stouter body form, 2.87‒2.91× as long as wide; elytra weakly impressed behind base, interstriae finely granulate-punctate, interstriae 3, 5, 7 with a few scattered erect bristle-like setae vs. elytra not weakly impressed behind base, interstriae reticulate–punctate, interstriae 3, 5, 7 without erect bristle-like setae.

Description (female). 2.1–2.18 mm long (mean 2.14, n = 2); 3.00–3.03× as long as wide, short and robust body form, brown in colour. Head. Epistoma anterior margin transverse, feebly elevated, with a row of short, closely set hair-like setae. Frons narrow, feebly convex, a weakly raised median line extending from epistoma in lower half of frons; median line narrow, not prominent; surface subshiny, finely granulate-punctate, granules above epistoma robust, densely placed, decreasing in size and sparser above (granules smaller and surface less rugulose in paratype); punctures minute, sparser above, with short, erect hairs. Eyes very large, fairly deeply emarginate, extending onto lower surface of head as well as onto frons. Submentum strongly impressed, small, narrowly triangular. Antenna with scape short and thick, as long as club. Pedicel as long as 4-segmented funicle. Antennal club type 4, wider than long (9/7), first segment slightly larger than second segment, apical margin convex on anterior face, second segment large, corneous, third segment soft. Pronotum. 1.14–1.17× as long as wide, in dorsal view, type 6, in lateral view with disc much longer than anterior slope, type 8. Base transverse, basal angles rounded, sides parallel in basal two– thirds, then narrowly rounded, apex weakly produced in middle and armed with two small asperities, anterior slope convex, finely, densely asperate, asperities transversely elongate, decreasing in size and becoming more closely placed towards low, indistinct summit, each with a moderately long semi-recumbent hair or very short appressed hair. Lateral margins obliquely costate. Disc reticulate, glabrous, weakly shining, regularly, densely, very finely, shallowly punctured. Elytra. About as wide as pronotum, 1.86× as long as wide, 1.60–1.63× as long as pronotum. Scutellum minute, concealed by elytra, visible on anterior slope of elytral base only. Elytral bases feebly convex, margin weakly carinate, humeral angles rounded. Elytra without mycangial opening, cylindrical from base to apical 2/5 then very strongly attenuate to very short, narrow apex. Disc strongly convex, except shallowly impressed areas just behind elytral bases; impressed areas finely, densely granulate-punctate; disc subshiny except impressed areas matt; striae and interstriae flat, striae not easily distinguishable from interstriae, with punctures shallow, subcontiguous, glabrous; interstriae 2× as wide as striae, with 2–3 irregular rows of fine granulate punctures, a few long erect hairs with flattened apex present on interstriae 3,5,7 near declivital summit (almost abraded in paratype), some longer setae on lateral margins of elytra. Declivity beginning at start of elytral constriction, slightly concave in apical third when viewed from side; less shiny than disc, nearly matt, striae and interstriae indistinguishable with dense and strongly confused punctures, each with an appressed or semi-appressed short, fine hair-like seta; setae increase in size and density toward apex; apex with long semi-erect hair-like setae, finely granulate, with slightly larger granules near the posterolateral margin. Legs. Procoxae contiguous; prosternal coxal piece short, pointed. Protibiae slender, posterior face inflated, granulate, apical 1/3 of outer margin with five short, robust socketed denticles. Meso- and metatibiae flattened; outer margins evenly rounded with five smaller socketed denticles. Male: Unknown. Etymology: Latin, from brevis = short, and cauda = tail, referring to the short elytra (noun in apposition). Distribution: THAILAND: Narathiwat Province.

Figures

FIGURE 1. Cryptoxyleborus brevicauda Sittichaya & Beaver sp. nov. female, holotype A) lateral view B) dorsal view C) latero-ventral view and antenna D) postero-lateral view E) frons.