Pachybrachis mcmeansi Barney, 2018

Barney, Robert J., 2018, Definition and Revision of the Atomarius Species-Group of North American Pachybrachis Chevrolat (Coleoptera: Chrysomelidae: Cryptocephalinae), Including Descriptions of Nine New Species, The Coleopterists Bulletin 72 (1), pp. 9-74 : 35

14. Pachybrachis mcmeansi Barney , new species Zoobank.org/ urn:lsid:zoobank.org:act:3CD01D6B-7098-4EAC-828A-652B1638A1EC ( Fig. 14 , Map 2B)

Holotype. Male, labeled “Mass. // Mid’ sex / Co [hand-inked, white paper] // 6 // H. C. FALL / COLLECTION [printed, white paper] // [circular blue disc signifying dissection by RJB] // HOLOTYPE / Pachybrachis / mcmeansi / R. J. Barney 2017 [printed, red paper].” Deposited in MCZ. The specimen is point-mounted with genitalia affixed to point. It is in excellent condition with all appendages intact. There are two paratypes (2♀♀) with identical collecting data.

Paratypes. 5766 52♀♀. See Appendix 14.

Description. Male. Yellow, with dark brown to black punctures, standard maculae diffuse, L = 2.08– 2.42 mm (mean = 2.32 mm, n = 10); W = 1.07–1.28 mm (mean = 1.22 mm, n = 10); L/W = 1.84–2.01 (mean = 1.91, n = 10). Head: Slightly wider than thoracic apex, HW = 0.71–0.86 mm (mean = 0.80 mm, n = 10); eyes widely separated, IOD = 0.20–0.28 mm (mean = 0.23 mm, n = 10); IOD/HW = 0.25–0.31 (mean = 0.29, n = 10); face yellow with large, dark brown to black, W-shaped macula connecting the vertex and bases of antennae and up to base of upper lobes of eyes, punctation dense in dark areas, antennae yellow-brown, not reaching elytral declivity. Pronotum: Yellow, with dark brown to black, M-shaped macula broadly diffuse, punctation dense in dark areas, more sparsely placed in pale areas, especially along lateral margins, PL = 0.64–0.77 mm (mean = 0.74 mm, n = 10); PW = 0.95–1.09 mm (mean = 1.04 mm, n = 10); PL/PW = 0.67–0.76 (mean = 0.71, n = 10). Elytra: Yellow with dark brown to black maculae in no particular pattern; punctation confused in baso-sutural region, striae incomplete basally, mostly regular laterally and apically. Pygidium: Finely punctate, weakly convex; dark brown to black, often with 2 small, oval, yellow maculae. Venter: Dark brown to black, yellow spot on last ventrite. Legs: Dark brown to black with yellow femoral and tibial spots. Genitalia: Median lobe in en-face view with large, oval OS within parallel-sided shaft, with reduced PRL. POL, best seen in the lateral view, slightly deflexed at ALM, thus creating a lateral ridge, and then further up towards apex it is deflexed at near 90° angle, thereby creating a triangular, arrowhead-shaped area with a gently rounded terminus and 2 posteriorly projecting, rounded denticles ( Fig. 14 ). EFW = 0.29–0.39 mm (mean = 0.31 mm, n = 10); AAM = 0.15– 0.21 mm (mean = 0.18, n = 10); AAL = 0.16– 0.21 mm (mean = 0.19 mm, n = 10); AAW = 0.16–0.19 mm (mean = 0.18 mm, n = 10); AAL/ AAW = 0.92–1.14 (mean = 1.06, n = 10). Long setae present along edges of arrowhead down to initial deflexation. AAL/AAW ca. 1.0 indicates arrowhead essentially an equilateral triangle. Twenty-four males from 10 states were dissected.

Female. As in male, except L = 2.30–2.63 mm (mean = 2.48 mm, n = 8); W = 1.19–1.36 mm (mean = 1.26 mm, n = 8); L/W = 1.85–2.21 (mean = 1.97, n = 8); HW = 0.81–0.92 mm (mean = 0.86 mm, n = 8); IOD = 0.18–0.34 mm (mean = 0.27 mm, n = 8); IOD/HW = 0.23–0.38 (mean = 0.31, n = 8).

Etymology. This species is named in recognition of Orlando F. McMeans, PhD, Vice President for Research and Public Service; Dean and Director, Douglass Land-Grant Institute; Director, Agricultural and Environmental Research Station; Executive Director, WVSU Research and Development Corporation; West Virginia State University, Institute, West Virginia, for his unwavering support of this research.

Remarks. Many of the specimens of this species were discovered in a unit tray in Fall’ s collection (MCZ-FALL) labeled as P. relictus . However, a dissection of Fall’ s P. relictus lectotype revealed a significantly different aedeagal median lobe.

Pachybrachis mcmeansi has a very wide aedeagal median lobe with a distinctive, very large, arrowhead-shaped POL, as does P. walteri . However, P. mcmeansi has a secondary narrowing pre-arrowhead-shaped POL, and P. walteri , found only in Florida and Georgia, has a third, middle denticle.

Distribution. This species is found in a scattered distribution from Maine to Arkansas (Map 2B).

Biological Notes. A label cited a potential host plant as Amorpha fruticosa L. in Arkansas.

Specimens Examined. See Appendix 14.

Figures

Fig. 14. Pachybrachis mcmeansi, holotype. 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.