Hylocurus schwarzi Blackman 1928

Atkinson, Thomas H., 2024, New species, new synonymy, taxonomic notes and new records of bark and ambrosia beetles from the southwestern United States and northern Mexico (Coleoptera: Curculionidae: Platypodinae and Scolytinae), Zootaxa 5424 (2), pp. 151-175 : 161-162

Hylocurus schwarzi Blackman 1928 , redescription, female

Fig. 7 (A–H)

Diagnosis. Males of this species lack the circumdeclivital ring of tubercles at the base of the declivity which is found in many species. It can be distinguished from others with a similar declivity by the lack of any frontal carina or impression and the small granules on the declivity of uniform size. Females can be distinguished from all known species by the prominent fossa with dense, incurved setae, in the center of the frons.

Male. Length pronotum: 1.13 mm; length elytra: 1.55 mm; total length: 2.68 mm; maximum width: 1.05 mm; length / width: 2.531 (n=3, including holotype).

Frons convex, shining, with a combination of deep punctures and wide rugosities, these arranged in a very roughly concentric fashion. No impressions or elevations present. Antennal scape short, rounded, barely longer than the pedicel. Pedicel rounded, about twice the length of the longest segment in the flagellum. Antennal club nearly round, segments with a corneous base and 3 procurved sutures marked by rows of setae.

Entire surface of pronotum reticulate. Anterior margin serrate, dense rugosities on anterior portion, at 2–3 × as long as wide, almost adjacent, becoming wider, lower and closer towards summit. Summit at middle of pronotum, not impressed behind. Disc with abundant, flattened, rugosities, lower than those on anterior slope; each with an anterior-directed seta, longest behind disc.

Striae on elytral disc impressed; punctures deep, separated in row by their width; almost as wide as interstriae. Interstriae with uniseriate punctures, becoming granulate towards posterior; those at base of declivity largest.

Declivity convex in lateral view. Strial punctures uniseriate on declivity, shallower and less closely spaced than on disc. Interstriae 3 and higher with uniseriate granules to apex, present only at base on interstriae 1 and 2. Interstria 9 becoming serrate towards apex, terminating before the groove formed by striae 9 and 10. Apex acute.

Female. Length pronotum: 0.89 mm; length elytra: 1.25mm; total length: 2.14 mm; maximum width: 0.84 mm; length / width: 2.453 (n=3).

Similar to male except as noted below.

Frons convex, rugosities dense, arranged concentrically. A large, deep fossa in middle of frons, with dense, golden, incurved setae.

Elytral disc and declivity similar to male except that interstrial granules smaller.

Material examined. United States: Texas: Victoria, [28.8574 N, 97.0281 W], 27-III-1902, E.A. Schwarz (holotype male, USNMENT01356336); Brazos Co., College Station, 30.5885 N, 96.2537 W, 17-III-2003, E.G. Riley ( TAMU, 1); Bastrop Co., Camp Swift, 30.2870 N, 97. 3050 W, 21-III – 4-IV-2003, Lindgren funnel trap, J.C. Abbot ( UTIC, 2); Grimes Co., Plantersville, [30.3328 N, 95.8617 W], 22-II-2007, bottle trap with ethanol, Smith, J.E. & Bogran, C. ( TAMU, 1); Travis Co., Austin, 30.2507 N, 97.6998 W, 8-VIII-2002, ex Diospyros texana ( Ebenaceae ), T.H. Atkinson ( UTIC, 1); Waller Co., Hempstead, [30.0972 N, 96.0781 W], 8-II-2007, Lindgren funnel trap, Smith, J.E. & Bogran, C. ( TAMU, 3);

Biology and Distribution. Like other species in Hylocurus , H. schwarzi excavates its galleries in the xylem of branches. The only reported host is Diospyros texana , but it is probably not host specific. It has been collected from southern Oklahoma through southern Texas. It probably occurs in northeastern Mexico as well.

Figures

FIGURE 7. Hylocurus schwarzi. Male holotype (USNMENT01356336): (A) Dorsal, (B) Lateral, (C) Frontal, (D) Posterior. Female: (E) Dorsal, (F) Lateral, (G) Frontal, (H) Posterior. Specimen data: A–D, Texas, Victoria, [28.8574 N, 97.0281 W], 27- III-1902, E.A. Schwarz (USNM); E–H, Texas, Brazos Co., College Station, 30.5885 N, 96.2537 W, 17-III-2003, E.G. Riley (TAMU). All photographs by the author.