Pachybrachis donneri Crotch, 1874

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 : 1034-1037

10. Pachybrachis donneri Crotch, 1874 ( Figs. 10 , 13H, I ; Map 2B)

Pachybrachys donneri Crotch 1874: 78 . LeConte 1880: 205 (taxonomy); Fall 1915: 334 (taxonomy).

Pachybrachis donneri: Riley et al. 2003: 157 (catalogue).

Pachybrachys brunneus Bowditch 1909: 238 . New synonymy.

Fall 1915: 335 (taxonomy).

Pachybrachis brunneus: Riley et al. 2003: 155 (catalogue).

Pachybrachys uteanus Fall 1915: 335 . New synonymy.

Pachybrachis uteanus: Riley et al. 2003: 164 (catalogue).

Types. Crotch (1874) described his type series as being not rare on willows at the eastern end of Donner Lake . The LeConte Collection ( MCZ-LEC) contains a series of six beetles (3♂♂ 3♀♀) from California, each with type labels. One male labeled “ ♂ // Cala. [printed, white paper] // J. L. LeConte / Coll. [printed, white paper] // TYPE / 6 [printed, white paper] / 5047 [hand-inked, red paper] // [circular blue disc signifying dissection by RJB]” was examined, dissected, and photographed ( Fig. 10 ) .

Bowditch (1909) reported a type series of four males and five females of P. brunneus from two locations in Arizona, Phoenix and Prescott. One of the males, labeled “Salt River / Phoenix / 5/30 Ariz. // ♂ // TYPE / F. C. B. Coll. [printed, red paper] // [circular blue disc signifying dissection by RJB] // LECTOTYPE / Pachybrachys / brunneus Fall 1915 / design. R. J. Barney 2019 [printed, red paper]”, was examined, dissected, and photographed and is hereby designated lectotype to stabilize the epithet ( Fig. 13H ).

Fall’ s male P. uteanus labeled “Am Fk Can / 23 6 Ut // Coll Hubbard / &Schwarz // TYPE [printed] / uteanus [hand-inked, white paper] // M.C.Z. / Type [printed] / 24986 [hand-inked, red paper] // H. C. FALL / COLLECTION // [circular blue disc signifying dissection by RJB] // LECTOTYPE / Pachybrachys / uteanus Fall 1915 / design. R. J. Barney 2019 [printed, red paper]” was examined, dissected, and photographed and is hereby designated lectotype to stabilize the epithet ( Fig. 13I ) .

Redescription. Male. Body color ranging from almost black with lateral margins yellow to primarily yellow with black markings on pronotum and elytra, sparsely covered in white pubescence; L = 2.27–2.94 mm (mean = 2.61 mm, n = 14); W = 1.21–1.57 mm (mean = 1.39 mm, n = 14); L/W = 1.77–1.94 (mean = 1.88, n = 14). Head: Not distinctly wider than thoracic apex, HW = 0.75–0.98 mm (mean = 0.86 mm, n = 14); eyes moderately separated, IOD = 0.19–0.39 mm (mean = 0.27 mm, n = 14); IOD/HW = 0.24–0.46 (mean = 0.32, n = 14); face variable from primarily black to yellow with median black/brown area between eyes, sparsely covered in white pubescence; antennae black/brown with varying amounts of yellow, not reaching elytral declivity. Pronotum: Color ranging from almost black with lateral margins yellow to primarily yellow with complete or partial, brown to black, M-shaped markings, with narrow, partial or entire, smooth median line, sparsely covered with white pubescence; PL = 0.72–1.01 mm (mean = 0.84 mm, n = 14); PW = 1.06–1.42 mm (mean = 1.19 mm, n = 14); PL/PW = 0.64–0.77 (mean = 0.70, n = 14). Elytra: Black with lateral margins yellow to primarily yellow with black markings, sparsely covered with white pubescence. Pygidium: Black to primarily yellow, with white pubescence. Venter: Black/brown with white pubescence. Legs: Black/brown to primarily yellow with white pubescence; front claws not enlarged. Genitalia. Median lobe in en-face view with large, oval OS, post-orificial length with extended tripartite or trident-shaped nodule, side nodules greatly reduced but evident, with visible setae on each side. Base to nodule straight in lateral view. Thirtyseven males from seven USA states and one Canadian province were dissected.

Female. As in male, except L = 2.86–3.43 mm (mean = 3.17 mm, n = 13); W = 1.56–1.89 mm (mean = 1.74 mm, n = 13); L/W = 1.76–1.92 (mean = 1.82, n = 13); HW = 0.94–1.24 mm (mean = 1.04 mm, n = 13); IOD = 0.23–0.56 mm (mean = 0.40 mm, n = 13); IOD/HW = 0.24–0.52 (mean = 0.39, n = 13).

Remarks. Fall (1915) recognized the similarity between P. donneri , P. uteanus , and P. brunneus , speculating that P. uteanus may only be a geographical race of P. analis , but that P. brunneus and P. donneri are “quite surely distinct”. Bowditch (1909) noted in his description that P. brunneus “Comes near analis, Lec ”. The trident-shaped aedeagal median lobe is quite distinct, easily distinguishing P. donneri from P. analis , and is the basis for creating these synonymies.

Distribution. Pachybrachis donneri is found from British Columbia, Canada to western Texas (Map 3A). Colorado, Texas, and Utah are new state records for P. donneri .

Biological Notes. Some specimens were collected on Populus sp. and Salix sp. in Montana and on Baccharis sp. and Salix sp. in Arizona. Clark et al. (2004) reported P. donneri in association with P. trichocarpa and Salix sp. Clark et al. (2004) reported P. brunneus in association with Salix sp. in Arizona.

Specimens Examined. See Appendix 10.

Figures

Fig. 10. Pachybrachis donneri, Mohave Co., Arizona. A–B) Dorsal and lateral habitus, respectively, C) Face, D) Pygidium, E–F) Median lobe of aedeagus, lateral and en-face views, respectively.

Fig. 13. Pachybrachis species, type specimens. A) P. connexus (female), B) P. integratus (female), C) P. morosus (female), D) P. haematodes (male), E) P. analis (female), F) P. marmoratus (female), G) P. desertus (male), H) P. brunneus (male), I) P. uteanus (male).