Pachybrachis erinae 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 : 43

19. Pachybrachis erinae Barney , new species Zoobank.org/ urn:lsid:zoobank.org:act:EF121C5D-E750-46AD-8463-A6935E158EF0 ( Fig. 19 , Map 3B)

Holotype. Male, labeled “ QUEBEC: Mont King / Parc de la Gatineau / 19.VIII.96. Battage / arbes. L. LeSage // Battage surtout / de Quercus rubra / mais aussi de / Quercus alba [printed, white paper] // [circular blue disc signifying dissection by RJB] // HOLOTYPE / Pachybrachis / erinae / R. J. Barney 2017 [printed, red paper].” Deposited in MCZ. The specimen is point-mounted with genitalia affixed to a second point. It is in excellent condition with all appendages intact.

Paratypes. 4066 27♀♀. See Appendix 19.

Description. Male. Yellow with rufous to fuscous punctures, standard maculae diffuse, often dark brown or fuscous; L = 1.90–2.20 mm (mean = 2.07 mm, n = 11); W = 0.98–1.17 mm (mean = 1.08 mm, n = 11); L/W = 1.84–2.00 (mean = 1.93, n = 11). Head: Slightly wider than thoracic apex, HW = 0.63-0.77 mm (mean = 0.70 mm, n = 11); eyes narrowly separated, IOD = 0.14–0.18 mm (mean = 0.16 mm, n = 11); IOD/HW = 0.20–0.24 (mean = 0.22, n = 11); face yellow with brown to black, W-shaped macula connecting the vertex and bases of antennae and up to base of upper lobe of eyes, punctation dense, antennae yellow-brown, not reaching elytral declivity. Pronotum: Yellow, M-shaped macula dark brown to black, broadly diffuse; incomplete punctation to lateral margins, PL = 0.56–0.71 mm (mean = 0.65 mm, n = 11); PW = 0.78–0.96 mm (mean = 0.88 mm, n = 11); PL/PW = 0.72–0.77 (mean = 0.74, n = 11). Elytra: Confused punctures in baso-sutural region, striae moderately impressed, irregular in middle, marginal interspace mostly impunctate. Pygidium: Dark brown to black with 2 oval, yellow maculae. Venter: Dark brown to black, upper sides of last ventrite yellow. Legs: Brown with standard yellow spots. Genitalia: Median lobe in en-face view wide, sides gently narrowing to ALM, then abruptly curved to extended terminus; pre- and post-orificial lengths negligible, OS large, with large, pigmented basal plates; median lobe in lateral view with inflated base, then narrowing at ALA, then inflated to ridgelike keel formed by 2 circular depressions as seen from sub-en-face view ( Fig. 19G ); DEO deflexed at near 60° angle, thereby creating a triangular, arrowhead-shaped area with a gently rounded terminus and 2 posteriorly projecting denticles. Arrowhead in dorsal view with a third, middle denticle that arises from distinct ridge formed along edge of inflated keel. Long setae present on rounded ALM and lateral edges of arrowheadshaped POL ( Fig. 19 ). Twenty-five males from eight states were dissected.

Female. As in male, except L = 2.17–2.38 mm (mean = 2.29 mm, n = 7); W = 1.18–1.33 mm (mean = 1.24 mm, n = 7); L/W = 1.74–1.92 (mean = 1.85, n = 7); HW = 0.75–0.83 mm (mean = 0.79 mm, n =7); IOD = 0.16–0.26 mm (mean = 0.22 mm, n = 7).

Etymology. This species is named in recognition of Erin Smith Daugherty, Blacksburg, Virginia.

Remarks. A large proportion of specimens (40%) of P. erinae were found from Québec, with a smattering from other states. Pachybrachis erinae superficially resembles P. relictus , but P. erinae is longer and narrower, with eyes closer together than P. relictus , thus providing a resemblance to Pachybrachis pectoralis (Melsheimer) , but without the ocular lines and enlarged foreclaws.

Distribution. This species is found from Québec and Michigan to Kentucky and South Carolina (Map 3B).

Biological Notes. Label data reported collection on Quercus alba L., Quercus rubra L., and Quercus sp. in Québec, Canada.

Specimens Examined. See Appendix 19.

Figures

Fig. 19. Pachybrachis erinae, 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, G) Median lobe of aedeagus, dorsal view.