Pachybrachis bloxham Riley and Barney

Riley, Edward G. & Barney, Robert J., 2015, Definition And Revision Of The Viduatus Species- Group Of North American Pachybrachis Chevrolat (Coleoptera: Chrysomelidae: Cryptocephalinae), The Coleopterists Bulletin 69 (1), pp. 25-59 : 40-41

5. Pachybrachis bloxham Riley and Barney , new species ( Figs. 15 , 19 ; Map 3)

Holotype. Male ,labeled “Fla: Leon Co. / Bloxham, hwy 20 / 20 Aug., 1980 / G. B. Marshall [printed, black on white] // HOLOTYPE / Pachybrachis / bloxham / Riley & Barney [printed, black on red].” Deposited in TAMU. The specimen is pointmounted and dissected, with abdomen and genitalia affixed to the point. It is in excellent condition with all appendages intact. There are eight paratypes (3♂♂ 5♀♀) with identical collecting data.

Paratypes. 7♂♂, 7♀♀ (Appendix 1).

Description. Male: Length 2.35–2.77 mm (mean = 2.53 mm, n = 7); width across humeri, 1.29–1.52 mm (mean = 1.38 mm, n = 7); W/L, 1.80–1.89 (mean = 1.83, n = 7). Head: Slightly wider than thoracic apex, width 0.90–1.07 mm (mean = 0.96 mm, n = 7); eyes bulging laterally, upper lobes widely separated, IOD 0.36–0.46 mm (mean = 0.40 mm, n = 7); IOD/HW 0.39–0.46 (mean = 0.41, n = 7); face black with macula adjacent to upper lobe of eye, triangular macula on lower frons, and area below antennal base yellow; surface closely punctate, surface dull; antennae yellowish brown, attaining elytral apex. Pronotum: Length 1.12–1.33 mm (mean = 1.22 mm, n = 7), width 0.83–0.99 mm (mean = 0.91 mm, n = 7), anterior width slightly less than basal width, lateral margin arcuate from base to anterior angle; PL/PW 0.70–0.78 (mean = 0.75, n = 7); black, M-shaped macula broad, complete, sharply defined, median arm of base of M-shaped macula reaching base of pronotum, lateral arms narrowly separated from pronotal base; punctation dense in black area, more sparsely placed in pale areas, especially along lateral margins; surface between punctation dull; scutellum black. Elytra: Each elytron with suture very narrowly black, and with 2 heavy black vittae that attain leading edge of declivity, discal vitta slightly wider than lateral vitta, lateral vitta complete, turned inward apically at leading edge of declivity; punctation generally confused and without impressed striae, some punctures often placed in short, serial arrangements on

Map 3. Distribution of Pachybrachis species based on specimens examined. P. viduatus (circles); P. chester

(diamonds); P. bloxham (stars).

sides and at apical declivity, costae not evident; surface between punctures dull. Pygidium: Finely punctate, weakly convex; black with large, confluent, oval, yellow macula occupying majority of surface. Venter: Black graded to dark brownish in areas, upper sides of last ventrite yellow. Legs: Yellow-brown, bases of femora and apices of tibiae mostly pale yellowish. Genitalia: Median lobe in en-face view of equal width throughout, side margins of shaft not tapered behind apicolateral curvature ( Fig. 19 ); length of postorificial space moderately long, ca. 3 times width of narrowest marginal space; lateral basal plates well-pigmented; median plate weakly pigmented, broad basally, narrowed distally. En-face outline with apicolateral margin abruptly rounded; distal en-face outline transverse, with distinct, narrowly triangular nodule. Beard conspicuous, consisting of apicolateral wisp on each side; setae of wisp dense, long, weakly graded in length, with longest medial in serial position, curved mesad. Ventral surface strongly swollen, with distinct keel; keel distinct basally, diminished distally before reaching terminus; distal profile strongly swollen to base of nodule, abruptly narrowed before terminus.

Female. As in male, except length 2.67–3.14 mm (mean = 2.83 mm, n = 7); width across humeri 1.45–1.66 mm (mean = 1.54 mm, n = 7); head width 0.99–1.15 mm (mean = 1.06 mm, n = 7); interocular distance 0.43–0.49 mm (mean = 0.45 mm, n = 7); IOD/HW 0.38–0.47 (mean = 0.42, n = 7); antennae nearly attaining declivity.

Etymology. This species is named for the type locality, and the name is used as a noun in apposition.

Remarks. The viduatus species-group characters, together with the heavy median elytral vittae, complete lateral elytral vittae, and the distinctive male genitalia, distinguish the species. Pachybrachis bloxham is definitively separable from P. chester , P. kentuckyensis , and P. viduatus by reference to the male genitalia, and the limited specimens available have the lateral elytral vitta complete. We have not separated females of these four species except through association with males, but females of P. bloxham can be separated from P. picturatus by the heavier black maculation and more dense and coarse punctation.

Distribution. Only 15 specimens can be conclusively determined as P. bloxham , and all are from a small area of the Florida panhandle (Map 3).

Biological Notes. No plant associations are known to us. We visited both known localities, which can be described as a mesic pineland and an open boggy field.

Specimens Examined. See Appendix 1.

Figures

Figs. 15–18. Pachybrachis species, dorsal and lateral habitus, face and pygidium. 15) P. bloxham, holotype;

Figs. 19–22. Pachybrachis species, median lobe, en-face and lateral views. 19) P. bloxham, holotype; 20) P. chester, holotype; 21) P. kentuckyensis; 22) P. viduatus.