Pachybrachis baja 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 : 1025

3. Pachybrachis baja Barney , new species Zoobank.org/ urn:lsid:zoobank.org:act:947D0D6E-6912-4B4F-9E8C-300F23EFEFC7 ( Fig. 3 ; Map 1B)

Holotype. Male labeled “ MEXICO: Baja Sur / Ramal a los Naranjos / 20-28 km W, 26 Aug / 1994, R. Turnbow // [circular blue disc signifying dissection by RJB] // HOLOTYPE / Pachybrachis / baja 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.

Paratypes. 65♂♂ and 47♀♀ are labeled “ PAR- ATYPE / Pachybrachis / baja Barney / R. J. Barney 2019 [printed, yellow paper]”. Deposited in AJGC, EGRC, RJBC, and UAIC (Appendix 3) .

Description. Male. Head and thorax dark red, partially obscured by dense, white pubescence, elytra luteous with dark red maculae ( Fig. 3 ); L = 2.42–2.70 mm (mean = 2.57 mm, n = 10); W = 1.35–1.48 mm (mean = 1.42 mm, n = 10); L/W = 1.74–1.86 (mean = 1.81, n = 10). Head: Distinctly wider than thoracic apex, HW = 0.99–1.10 mm (mean = 1.04 mm, n = 10); eyes widely separated, IOD = 0.25–0.34 mm (mean = 0.29 mm, n = 10); IOD/HW = 0.24–0.31 (mean = 0.28, n = 10); face primarily dark red with dense, white, recumbent pubescence; antennae brown-yellow, not reaching elytral declivity. Pronotum: Dark red with luteous borders, covered, but not obscured, with white pubescence; PL = 0.81–0.98 mm (mean = 0.89 mm, n = 10); PW = 1.22–1.36 mm (mean = 1.28 mm, n = 10); PL/PW = 0.66–0.73 (mean = 0.69, n = 10). Elytra: Dull luteous with white pubescence and variable, indistinct dark red maculae. Pygidium: Dark red with 2 oval yellow spots and white pubescence. Venter: Dark red with white pubescence. Legs: Luteous with dark areas and white pubescence; front claws not enlarged. Genitalia: Median lobe in en-face view slightly narrowed before oval OS, rounded with visible setae on each side of a nodule. Median lobe evenly wide without distinct narrowing in lateral view. Six males from Baja, Mexico were dissected.

Female. As in male, except L = 2.62–3.06 mm (mean = 2.87 mm, n = 10); W = 1.50–1.75 mm (mean = 1.63 mm, n = 10); L/W = 1.73–1.80 (mean = 1.76, n = 10); HW = 1.08–1.23 mm (mean = 1.15 mm, n = 10); IOD = 0.30–0.45 mm (mean = 0.39 mm, n = 10); IOD/HW = 0.27–0.38 (mean = 0.34, n = 10).

Etymology. Pachybrachis baja is named in honor of the area of Mexico where all the specimens known to me have been found.

Remarks. Similar to P. wickhami , P. baja is a relatively unusual species for Pachybrachis in that the pubescence and coloring of the head and thorax is distinctly different from the elytra. However, P. baja is larger, less densely pubescent, and dark red rather than black. The aedeagal median lobe of P. baja is wider in en-face view, and the narrowing seen in lateral view of P. wickhami is not present in P. baja . I have not seen a specimen of P. baja from the USA, but it has been included in this speciesgroup due to similarity to P. wickhami .

Distribution. This species is found on the Baja California Peninsula of Mexico (Map 1B).

Biological Notes. Some specimens were collected via blacklight.

Specimens Examined. See Appendix 3.

Figures

Fig. 3. Pachybrachis baja, holotype. A–B) Dorsal and lateral habitus, respectively, C) Face, D) Pygidium, E–F) Median lobe of aedeagus, lateral and en-face views, respectively.