Pachybrachis gibbyi Barney

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: 47-50

publication ID 10.1649/0010-065X-72.1.9

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Pachybrachis gibbyi Barney

new species

21. Pachybrachis gibbyi Barney   , new species ( Fig. 21 View Fig , Map 3A)

Holotype. Male , labeled “Fla: Liberty Co. / 9mi. N. Bristol / VII-4-1982 / Coll. E. G. Riley [printed, white paper] // [circular blue disc signifying dissection by RJB] // HOLOTYPE / Pachybrachis   / gibbyi   / R. J. Barney 2017 [printed, red paper].” Deposited in TAMU. The specimen is point- mounted with genitalia affixed to a second point. It is in excellent condition with all appendages intact. There are four paratypes (4♀♀) with identical collecting data.  

Paratypes. 4♀♀. See Appendix 21.

Description. Male. Small, yellow with light brown punctures; L = 1.76 mm (n = 1); W = 0.90 mm (n = 1); L/W = 1.97 (n = 1). Head: Slightly wider than thoracic apex, HW = 0.59 mm (n = 1); eyes narrowly separated, IOD = 0.13 mm

Map 1. Distribution of Pachybrachis species   based upon specimens examined. A) P. lodingi   (black), P. quadrioculatus  

(red), and P. calcaratus   (blue), B) P. atomarius   (red) and P. stygicus   (black), C) P. jacobi   (black) and P. luctuosus   (red).

Map 2. Distribution of Pachybrachis species   based upon specimens examined. A) P. varians   (black), P. matthewi  

(red), and P. relictus   (blue), B) P. parvus   (red), P. dixianus   (black), P. caroleae   (star), and P. mcmeansi   (blue).

(n = 1); IOD/HW = 0.22 (n = 1); face yellow with brown, W-shaped macula connecting 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, Mshaped macula brown, broadly diffuse; incomplete punctation to lateral margins, PL = 0.58 mm (n = 1); PW = 0.75 mm (n = 1); PL/PW = 0.78 (n = 1). Elytra: Yellow, striae mostly regular, punctures brown, standard maculae reduced. Pygidium: Brown with 2 oval, yellow maculae, upper sides of last ventrite yellow. Venter: Brown. Legs: Yellow. Genitalia: Median lobe in en-face view with parallel-sided shaft, abruptly narrowing at ALM to extended POL deflexed 60° at ALM, thereby creating a triangular, arrowhead-shaped area with a gently rounded terminus and 2 posteriorly projecting denticles, with setae along edges ( Fig. 21 View Fig ). One male from one state was dissected.

Female. As in male, except, L = 2.01–2.18 mm (mean = 2.10 mm, n = 4); W = 1.03–1.14 mm

Map 3. Distribution of Pachybrachis species   based upon specimens examined. A) P. charlotteae   (black), P. walteri   (red), P. confederatus   (blue), P. cephalicus   (green diamond), and P. gibbyi   (yellow square), B) P. erinae   (black) and P. gibsoni   (red).

(mean = 1.10 mm, n = 4); L/W = 1.85–1.96 (mean = 1.91, n = 4); HW = 0.68–0.75 mm (mean = 0.72 mm, n = 4); IOD = 0.11–0.17 mm (mean = 0.14 mm, n = 4); IOD/HW = 0.17–0.22 (mean = 0.19, n = 4).

Etymology. This species is named for George Albert Gibson, formerly of Broadview, Illinois, in posthumous recognition and appreciation of his contribution to my youthful development and familial identification.

Remarks. This species is small and narrow, with eyes extremely close together, thus providing a resemblance to P. pectoralis   , but without the ocular lines and enlarged foreclaws. Future collection of additional specimens may provide some insight on the similarity of P. gibbyi   to P. erinae   .

Distribution. There are only five confirmed specimens from a single collecting event in the Florida panhandle (Map 3A).

Biological Notes. Specimens were collected from a habitat dominated by turkey oak, Q. laevis   (E. G. Riley, personal communication).

Specimens Examined. See Appendix 21.