Pachybrachis densus Bowditch, 1909

2. Pachybrachis densus Bowditch, 1909

( Figs. 2 View Fig , 5a View Fig , Map 1 View Map 1 )

Pachybrachys densus Bowditch 1909: 242 ; Fall 1915: 339 (taxonomy).

Pachybrachis densus: Riley et al. 2003: 157 (catalog).

Type. Bowditch (1909) described P. densus from a pair of specimens from Arizona. The female specimen, hereby designated paralectotype, is labeled “Ari. // ♀ // densus / Type ♀ [hand-inked, white paper] // TYPE / F. C. B. Coll. [printed, pink paper] // Type [printed] / 8664 [hand-inked, red paper] // PARALECTOTYPE / Pachybrachys / densus Bowditch / R. J. Barney 2020 [printed, yellow paper]”. This specimen was examined and photographed ( Fig. 5a View Fig ) . The male specimen, hereby designated lectotype, is labeled “Ari. // ♂ // densus / Type ♂ [hand-inked, white paper] // TYPE / F. C. B. Coll. [printed, pink paper] // [circular blue disc signifying dissection by RJB] // LECTOTYPE / Pachybrachys / densus Bowditch / R. J. Barney 2020 [printed, red paper]”, and was examined, dissected, and photographed ( Fig. 2 View Fig ) .

Redescription. Male. Small, pale dirty-yellow, very thickly, diffusely punctate ( Fig. 2 View Fig ); L = 1.66–1.74 mm (mean = 1.69 mm, n = 3); W = 0.87– 0.90 mm (mean = 0.89 mm, n = 3); L/W = 1.86–1.92 (mean = 1.90, n = 3). Head: Distinctly wider than thoracic apex, HW = 0.68–0.70 mm (mean = 0.68 mm, n = 3); eyes moderately separated, with ocular lines, IOD = 0.21–0.27 mm (mean = 0.23 mm, n = 3); IOD/HW = 0.32–0.34 (mean = 0.33, n = 3); face pale dirty-yellow, densely punctate, ocular lines close to upper lobes of eyes; antennae not reaching elytral declivity. Pronotum: Pale dirty-yellow, densely punctate; PL = 0.50– 0.54 mm (mean = 0.52 mm, n = 3); PW = 0.71–0.74 mm (mean = 0.73 mm, n = 3); PL/PW = 0.69–0.73 (mean = 0.71, n = 3). Elytra: Pale dirtyyellow, densely punctate, striation wanting. Pygidium: Black with 2 oval yellow spots. Venter: Black with yellow side and apical margins. Legs: Yellow with brown spots, front claws of male not enlarged. Genitalia: Median lobe in en-face view reveals a pronounced extension of the POL, with the ALM extending forward on either side of a narrowly extended T ( Fig. 2 View Fig ). The median lobe is thickened in lateral view, revealing a ridge-like keel extending up to and along the narrow projecting T. Two males from one USA state were dissected.

Female. As in male, except L = 2.00 mm ( n = 1); W = 1.05 mm ( n = 1); L/W = 1.90 mm ( n = 1); HW = 0.78 mm ( n = 1); IOD = 0.25 mm ( n = 1); IOD/HW = 0.32 ( n = 1).

Remarks. Fall (1915) summarized P. densus as “An easily recognized species by its small size, dull dingy yellow color and dense diffuse punctuation”. Pachybrachis densus is undoubtedly very closely related to P. americanus ; however, P. americanus is significantly larger, with prominent alatates on both sides of the extended aedeagal terminus and without the ridge-like keel of P. densus .

Distribution. Riley et al. (2003) reported this species from Arizona and California ( Map 1 View Map 1 ).

Specimens Examined. Lectotype, paralectotype + 1 specimen. USA: ARIZONA: Unknown county [ 1♂ 1♀, LECTOTYPE & PARALECTOTYPE, MCZ-BOW]; Morrison, Hubbard & Schwarz Collection [ 1♂, Fall 1915 Revis., USNM].