Pachybrachis madera 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 : 1041

12. Pachybrachis madera Barney , new species Zoobank.org/ urn:lsid:zoobank.org:act:D31BCA87-E46A-49A0-A87E-03A2F0B02CE9 ( Fig. 12 ; Map 1B)

Holotype. Male , labeled “ ARIZONA: Sta. Cruz Co / Madera Canyon / VIII.21.1981 / Coll. R. Davidson // white light // [circular blue disc signifying dissection by RJB] // HOLOTYPE / Pachybrachis / madera Barney / R. J. Barney 2019 [printed, red paper]”. Deposited in CMNH. The specimen is point-mounted with the genitalia affixed to a second point. It is in excellent condition with all appendages intact. There are four beetles (3♂♂ 1♀) having identical collecting data as the holotype.

Paratypes. Twenty-eight specimens (19♂♂ 9♀♀) are labeled “ PARATYPE / Pachybrachis / madera Barney / R. J. Barney 2019 [printed, yellow paper]”. Deposited in CMNH, UAIC, and UAIC (Appendix 12) .

Description. Male. Yellow with very fine, white pubescence and diffuse areas of red-orange maculae; L = 2.97–3.57 mm (mean = 3.29 mm, n = 10); W = 1.62–1.93 mm (mean = 1.79 mm, n = 10); L/W = 1.79–1.86 (mean = 1.84, n = 10). Head: Slightly wider than thoracic apex, HW = 1.05–1.25 mm (mean = 1.13 mm, n = 10); eyes closely separated, IOD = 0.17–0.28 mm (mean = 0.23 mm, n = 10); IOD/HW = 0.16–0.24 (mean = 0.21, n = 10); face dark red-orange with long, white pubescence; antennae yellow-brown, not reaching elytral declivity. Pronotum: Yellow with white pubescence, often with yellow-orange maculae on basal portion, with narrow midline on anterior portion, lateral margin arcuate basally, PL = 0.90–1.12 mm (mean = 1.01 mm, n = 10); PW = 1.42–1.66 mm (mean = 1.52 mm, n = 10); PL/PW = 0.64–0.69 (mean = 0.66, n = 10). Elytra: Yellow with fine, white pubescence, brown punctures arranged in regular rows only laterally, indistinct red-orange areas in no particular pattern. Pygidium: Yellow with white pubescence. Venter: Brown with white pubescence. Legs: Yellow with white pubescence; front claws distinctly enlarged. Genitalia: Median lobe in en-face view with large, circular OS above distinct narrowing, terminating in a nodule. Ventral surface greatly inflated in lateral view, distal end with keel separating 2 depressed areas with setae. Eight 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 (mean = 0.34 mm, n = 10); IOD/HW = 0.27–0.31 (mean = 0.29, n = 10).

Etymology. Pachybrachis madera is named in honor of the famous collecting area of Arizona, Madera Canyon, where the holotype was found.

Remarks. The fine white pubescence on the elytra, which is not present on the pronotum and very difficult to detect, plus the very large median lobe, makes P. madera particularly distinctive relative to the other members of this pubescent speciesgroup.

Distribution. This species is found in southeastern Arizona (Map 1B).

Biological Notes. Quercus sp. was noted as a potential host plant in Madera Canyon, Arizona. Many other specimens were collected at UV blacklight.

Specimens Examined. See Appendix 12.

Figures

Fig. 12. Pachybrachis madera, holotype. A–B) Dorsal and lateral habitus, respectively, C) Face, D) Pygidium, E–F) Median lobe of aedeagus, lateral and en-face views, respectively.