Pachybrachis gilberti Barney, 2019

Barney, Robert J., 2019, Definition and Revision of the Pubescens Species-Group of North American Pachybrachis Chevrolat (Coleoptera: Chrysomelidae: Cryptocephalinae), Including Descriptions of Three New Species, The Coleopterists Bulletin 73 (4), pp. 1017-1048 : 1037-1041

11. Pachybrachis gilberti Barney , new species Zoobank.org/ urn:lsid:zoobank.org:act:4B1C4C06-2CCC-4906-913A-053F602223D3 ( Fig. 11 ; Map 1A)

Holotype. Male , labeled “ARIZ: Cochise Co. Cave Cr. / Cyn., 3 mi. W Portal VIII-9-00, / 5120ft. A. Gilbert & N. Smith / 31 o 53.023’N - 109 o 10.715’W // [circular blue disc signifying dissection by RJB] // HOLOTYPE / Pachybrachis / gilberti Barney / R. J. Barney 2019 [printed, red paper]”. Deposited in MCZ. The specimen is point-mounted with the genitalia affixed to a second point. It is in excellent condition with all appendages intact. There are 18 beetles (7♂♂ 11♀♀) having identical collecting data as the holotype.

Paratypes. Eighty-one specimens (32♂♂ 49♀♀) are labeled “ PARATYPE / Pachybrachis / gilberti Barney / R. J. Barney 2019 [printed, yellow paper]”. Deposited in AJGC, BYUC, and RJBC (Appendix 11) .

Description. Male. Dark reddish brown with white pubescence and diffuse areas of yelloworange maculae; L = 2.71–3.15 mm (mean = 2.93 mm, n = 10); W = 1.34–1.59 mm (mean = 1.46 mm, n = 10); L/W = 1.95–2.04 (mean = 2.00, n = 10). Head: Distinctly wider than thoracic apex, HW = 0.98–1.17 mm (mean = 1.06 mm, n = 10); eyes moderately separated, IOD = 0.20–0.36 mm (mean = 0.28 mm, n = 10); IOD/HW = 0.19–0.31 (mean = 0.26, n = 10); face dark reddish brown with long, white pubescence; antennae red-brown, not reaching elytral declivity. Pronotum: Dark reddish brown with white pubescence, often with a partially raised, yellow-orange maculae, midline much reduced, anterior width much less than basal width, lateral margin arcuate basally, PL = 0.95–1.15 mm (mean = 1.04 mm, n = 10); PW = 1.20–1.42 mm (mean = 1.32 mm, n = 10); PL/PW = 0.76–0.83 (mean = 0.78, n = 10). Elytra: Dark reddish brown with white pubescence, often with minimally raised, yellow-orange areas, most evident at apical, lateral, and basal edges. Pygidium: Dark reddish brown with white pubescence. Venter: Dark reddish brown with white pubescence. Legs: Dark reddish brown with white pubescence; front claws distinctly enlarged. Genitalia: Median lobe in en-face view with large, oval OS, sclerotized basal plates, and extended post-orificial length, terminating in nodule. Ventral surface distinctly rounded in lateral view, distal half with a smooth midline separating a setal field on each side. Four males from one state were dissected.

Female. As in male, except L = 2.98–3.34 mm (mean = 3.12 mm, n = 10); W = 1.53–1.76 mm (mean = 1.59 mm, n = 10); L/W = 1.89–2.05 (mean = 1.96, n = 10); HW = 1.06–1.32 mm (mean = 1.16 mm, n = 10); IOD = 0.29–0.40 mm

Map 1. Distribution of Pachybrachis species , based upon specimens examined. A) P. integratus (orange), P. vigilans (dark blue), P. connexus (purple), and P. gilberti (red x). B) P. wickhami (blue), P. baja (red), P. madera (purple x), P. morosus , black form (black), and P. morosus , black with orange-red form = haematodes sensu Suffrian (1852) (orange).

Map 2. Distribution of Pachybrachis species , based upon specimens examined. A) P. analis (black) and P. xanti

(yellow). B) P. donneri (black) and P. thoracicus (orange).

(mean = 0.34 mm, n = 10); IOD/HW = 0.27–0.31 (mean = 0.29, n = 10).

Etymology. This species is named in recognition of Arthur J. Gilbert, retired from the Pest Detection/ Emergency Projects Branch, Plant Health & Pest Prevention Services, California Department of Food and Agriculture, who collected the majority of the specimens and encouraged me to describe this new species.

Remarks. Pachybrachis gilberti is easily recognized by its narrow shape, almost purple coloration with yellow highlights, and bulging eyes.

Distribution. This species is found in southeastern Arizona, with a disjunct specimen from northeast Mexico (Map 1A).

Biological Notes. Mimosa aculeaticarpa , A. constricta , and Quercus sp. were noted on labels as potential host plants in Arizona.

Specimens Examined. See Appendix 11.

Figures

Fig. 11. Pachybrachis gilberti, holotype. A–B) Dorsal and lateral habitus, respectively, C) Face, D) Pygidium, E–F) Median lobe of aedeagus, lateral and en-face views, respectively.