Urocorthylus hirtellus Petrov, Mandelshtam & Beaver, 2007

Johnson, Andrew J., Sittichaya, Wisut, Lai, Shengchang, Li, You & Beaver, Roger A., 2023, The tribal placement of Urocorthylus Petrov, Mandelshtam & Beaver, with a description of the male of U. hirtellus Petrov et al., and notes on its biology (Coleoptera: Curculionidae: Scolytinae), Zootaxa 5306 (1), pp. 116-126 : 119-121

Urocorthylus hirtellus Petrov, Mandelshtam & Beaver, 2007

Figs 2‒6

Urocorthylus hirtellus Petrov, Mandelshtam & Beaver, 2007: 251 .

The species was described from the female only ( Fig. 3 ). Here, we describe the male ( Fig. 4 ), based on specimens collected in Yunnan province in south-western China, and in Chaiyaphum province in the northeastern region of Thailand.

Masc. nov. 2.58–3.15 mm long (mean 2.82, n=5), 2.36–2.52 times as long as wide (mean 2.43, n=5). Coloration. Bicolored, pronotal base (or pronotum as a whole) and appendages ferruginous, pronotal anterior slope and elytra black. Head brown, paler ventrally, pronotum brown ventrally, abdomen blackish brown, antennae and legs yellowish. Head. Epistoma entire, weakly sinuate above, with a row of moderately long hair-like setae. Frons below upper margin of eyes flat, upper part slightly convex, subshining, without longitudinal medial line; coarsely, densely rugose-punctate, punctures smaller, denser and shallower toward epistoma, bearing long, erect hair-like setae. Eye moderately large, broad, with a small, shallow emargination just above antennal insertion, upper portion distinctly smaller than lower part. Submentum moderately sized, triangular, punctate, with short erect hairlike setae. Antenna. Scape clavate, shorter than club. Pedicel slightly narrower than scape, shorter than funicle. Funicle 2- segmented, segment 1 shorter than pedicel, segment 2 small, inconspicuous. Antennal club oval, about 1.5 times as long as wide, compressed, without visible sutures or septa, densely and uniformly pubescent, except for triangular or parallel-sided area at the base), glabrous, shining area extending about half length of club. Pronotum. 1.04–1.11 times as long as wide (mean 1.08, n=5), sides parallel in basal half, then narrowing to rounded apex, without a distinct pre-apical constriction; anterior margin with 4 or 5 small serrations; anterior slope with subcontiguous small asperities, flatter, more transverse and almost imbricate in middle, smaller and more widely separated towards sides, becoming lower and narrower towards summit, slope with a mixture of less numerous, fine, long, erect, hair-like setae, and similar but more numerous, shorter, semi-recumbent setae; disc densely granulate-punctate behind summit becoming punctate towards base; sides densely, finely punctate; surface smooth, shining between punctures; disc and sides with dense, very fine, forwardly-directed, appressed hairs of variable length, and less dense scattered, long, erect, hair-like setae; posterior margin sinuate with a fringe of short, posteriorly-directed setae below the margin. Scutellum. Large, tongue-shaped, shining, impunctate, contrasting with subshining, strongly punctured elytra. Elytra. 1.28–1.54 times as long as wide (mean 1.42, n=5), 1.27–1.52 times as long as pronotum (mean 1.40, n=5); elytral bases slightly concave, as wide as pronotum, subparallel in basal 2/3, then strongly angled to apex, broadest at upper margin of declivity. Disc slightly convex, subshining, striae and interstriae obsolete near base, very densely rugulose-punctate, except laterally where deeply punctured; apical half of disc with impressed striae and ridged interstriae, the latter with an irregular row of tubercles; disc with a dense covering comprising sparser, long, erect hair–like setae, and more numerous, shorter, semi recumbent, plumose setae, the latter extremely dense on posterior half of elytra giving a woolly appearance. Declivity abruptly truncate, beginning in posterior 2/3 of elytra; striae impressed, narrow, with 3 or 4 irregular rows of short, plumose setae; interstriae ridged, each with a row of shining, rounded tubercles, interstriae 1 broader than outer interstriae and with additional scattered granules and rugosities, interstrial setae distinctly shorter than on disc; interstriae 1 at apex of elytra with a pair of small, weakly tapering processes with rounded tips, the size and form varying between individuals, dorsal face of processes, densely punctured with minute, very short setae. Legs. Procoxae slightly separated, Protibia not flattened, armed by 3 or 4 socketed denticles on anterior margin. Meso- and metatibiae flat, with denticles on the apical third. Proventriculus. Apical plate approximately 1/3 of the length. Median suture open, with teeth along medial margin. Aedeagus. Penis apodemes separate, and about a third of the total length. Penis body broad, about 3.0 times as long as wide. Tegmen broad, strongly sclerotized, appearing to be sclerotized over its entire circumference. Spiculum gastrale narrow. Base of flagellum membranous with no sclerotization.

Material examined for description of male. CHINA, Yunnan, Jing-Hong city, Menghai co. , Na-ban-he Nat. Res., Guo-men-shan, 22°14′46.54′′N, 100°36′10.2′′E, 1033 m, ex Cyclobalanopsis sp. , 28.i.2020, S-C. Lai ( RABC, 2) . THAILAND, Chaiyaphum, Phu Khieo Wildlife Sanctuary headquarters, 16°23'00.4"N 101°33'27.0"E, 900 m, Dry-dipterocarp forest with pine subtype, ex. semi-dry branch of Lithocarpus sp. , 21.vii.2019, W. Sittichaya ( WSTC, 2; RABC, 1) .

Additional new records. CHINA: Yunnan, near Pu′er city, ex sticky trap on tree trunk, 10.v.-07.vi.2012, T. Petrice & R. Haack ( UFFE 19886 : 1) ; Yunnan, Meng-hai Co., Jing-hong city, Guo-men-shan, Na-ban-he Nature Reserve , mixed forest, ex Quercus glauca , c. 60 cm diameter, 28.i.2018, S-C. Lai ( UFFE 35169-35170 : 1 male, 1 female (sequenced by S-C. Lai); JXAU, 18); as previous except: reared from bark, Y. Li ( UFFE 30354–30355 , 30357–30363 ; 32072–32073: 41) .

Distribution. China (Yunnan), Thailand (Chiang Mai, Chaiyaphum), Vietnam (Vinh Phuc).

Biology. As noted earlier, it had been assumed that the species was an ambrosia beetle ( Petrov et al. 2007; Beaver et al. 2014; Wang et al. 2017). A large series was collected from a fallen Quercus glauca , approximately 60 cm in diameter in China (Yunnan). The larval galleries were within the thick bark ( Fig. 5 ), although the nuptial gallery and early development was not evident. No symbiotic fungi were observed in the galleries. Pupation chambers were in the thick bark away from the parental galleries, as in other related Dryocoetini such as Taphrorychus (e.g. Balachowsky 1949; Schönherr & Krautwurst 1979). The adults emerge through individual exit holes in the bark ( Fig. 6 ). The species has also been collected in Lithocarpus sp. in Thailand (see above). The only other species in the genus, U. fanii Wang, Beaver & Hulcr was collected from Lithocarpus hancei ( Wang et al. 2017) . All host records are from trees in the family Fagaceae . It appears likely that the genus is specific to this family. Both species are montane species, collected at altitudes from 650‒1030 m, and probably largely confined to the hill evergreen forests of the region, in which Fagaceae is the dominant tree family.

Figures

FIGURE 2. Urocorthylus hirtellus male, A) Lateral view with elytron removed showing metanepisternal spine (UFFE:30356), B) Proventriculus (UFFE:30356), C–D) Aedeagus (UFFE:30363).

FIGURE 3. Urocorthylus hirtellus female, JXAU_S20180128001, A) dorsal view, B) lateral view, C) frons, D) antenna, E) declivital oblique, F) declivital face.

FIGURE 4. Urocorthylus hirtellus male, JXAU_S20180128001, A) dorsal view, B) lateral view, C) frons, D) antenna, E) declivital oblique, F) declivital face.

FIGURE 5. Urocorthylus hirtellus larval galleries in bark of Quercus glauca.

FIGURE 6. Urocorthylus hirtellus emergence holes of adults in bark of Quercus glauca.