Pachybrachis pinguescens, Fall, 1915

Barney, Robert J., 2021, Definition and Revision of the cylindricus Species-Group of North American Pachybrachis Chevrolat (Coleoptera: Chrysomelidae: Cryptocephalinae), Including Descriptions of Six New Species, The Coleopterists Bulletin 75 (4), pp. 723-748 : 734-737

7. PACHYBRACHIS pINgUeSCeNS Fall, 1915 ( Figs. 7 , 14A )

Pachybrachys pinguescens Fall 1915: 438 . Pachybrachis pinguescens Fall : Riley et al. 2003:

162 (catalog).

Type. The only male Fall examined, hereby designated lectotype, labeled “Ashfork/18.6 [hand-inked] Ar [printed, white paper]//Barber&/ SchwarzColl [printed, white paper]//35 [printed, white paper]// pinguescens Fall [hand-inked]/ Fall 1915 Revis [printed, white paper]// U.S. N.M./ Paratype [printed, red paper]//[circular blue disc signifying dissection by RJB]// LECTOTYPE / Pachybrachys / pinguescens Fall /R. J. Barney 2021 [printed, red paper]”, was examined, dissected, and photographed ( Fig. 7 ). Fall’s (1915) type female, now a paralectotype, labeled “Indpndce/Cal [printed, white paper]//05 [hand-inked]/June [printed, white paper]// TYPE [printed]/ pingues -/ cens [hand-inked, white paper]//M.C.Z./Type [printed]/24965 [hand-inked, red paper]//H.C. FALL /COLLECTION [printed, white paper]// PARALECTOTYPE / Pachybrachys / pinguescens Fall /R. J. Barney 2021 [printed, yellow paper]”, was examined and photographed ( Fig. 7H ).

Redescription. Male. Large, black and yellow maculate ( Fig. 7 ); L = 3.47–3.54 mm (mean = 3.51 mm, n = 2); W = 1.82–1.89 mm (mean = 1.85 mm, n = 2); L/W = 1.84–1.94 (mean = 1.89, n = 2). Head: Not wider than thoracic apex, HW = 1.22–1.27 mm (mean = 1.25 mm, n = 2); eyes moderately separat- ed, without ocular lines, IOD = 0.30–0.34 mm (mean = 0.32 mm, n = 2); IOD/HW = 0.25–0.26 (mean = 0.26, n = 2); face yellow with large, black macula descending from the vertex and between the upper lobes of eyes, punctation dense in dark areas, antennae progressing from yellow to brown to apical black, not reaching elytral declivity. Pronotum: Yellow with broad, M-shaped black macula, densely punctate, less so at margins and median line, strongly narrowed apically; PL = 1.09–1.13 mm (mean = 1.11 mm, n = 2); PW = 1.69–1.76 mm (mean = 1.72 mm, n = 2); PL/PW = 0.64–0.65 (mean = 0.64, n = 2). Elytra: Yellow with standard black maculae, densely punctate in baso-sutural area, striae irregular. Pygidium: Black with 2 oval conjoined yellow spots. Venter: Black with yellow side and apical margins. Legs: Yellow with brown spots, front claws of male greatly enlarged. Genitalia: Median lobe in en-face view shows a large, oval OS, with a wide projecting terminus, bounded on each side with large wisps at the ALM. The lateral view reveals a medium-sized, darkened sharp-edged keel, projecting between the bases of the wisps. A sub view of the median lobe shows that the keel ridge is not grooved or split. Four males from Arizona were dissected.

Female. As in male, except L = 4.06 mm (n = 1); W = 2.20 mm (n = 1); L/W = 1.84 (n = 1); HW = 1.48 mm (n = 1); IOD = 0.51 mm (n = 1); IOD/HW = 0.34 (n = 1).

Remarks. Fall (1915) based his description of P. pinguescens on two specimens: a female from California, which he called the type, and a male from Arizona. The median lobe of the Arizona male appears to be identical to P. chaoticus . Fall emphasized the extensive black markings and included P. pinguescens in his Group E key of species that are wholly or in great part black. It is not inconceivable that P. pinguescens is but a darker form of P. chaoticus .

Fall surmised that P.pinguescens was closely allied with Pachybrachis californicus Fall. However , an examination of the aedeagal median lobe of the P. californicus type found it to be without the keel and wisps that characterize this species-group.

Distribution. Riley et al. (2003) reported P. pinguescens from Arizona and California ( Fig. 14A ).

Specimens Examined. Three specimens, including the lectotype and paralectotype. USA: ARIZONA: Yavapai Co., Ash Fork, 27.vi.1892 [1♂, USNM]; same data, except 18.vi, Barber & Schwarz [1♂, Fall 1915 Revis., LECTOTYPE, USNM]. CALIFORNIA: Inyo Co. , Independence, vi, Fenyes [1♀, PARALECTOTYPE, MCZ-FALL] .

Figures

Fig. 7. Pachybrachis pinguescens, Ash Fork, Arizona, lectotype. A) Dorsal habitus, B) Lateral habitus, C) Face, D) Pygidium, E) Median lobe of aedeagus, lateral view, F) Median lobe of aedeagus, en-face view, G) Median lobe of aedeagus, sub view, H) Female paralectotype.

Fig. 14. Distribution of Pachybrachis species, based only upon specimens examined in this study. A) P. hybridus (black), P. turgidicollis (red), P. texasensis, new species (green), P. chaoticus (blue), P. pinguescens (orange), P. crassus (purple), B) P. saguaro, new species (black), P. peninsularis (purple), P. cylindricus (red), P. huachuca, new species (orange), P. hurricane, new species (gray), P. ephedra, new species (blue), and P. ashfork, new species (green).