Pachybrachis matthewi 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: 27-29

publication ID 10.1649/0010-065X-72.1.9

publication LSID

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Pachybrachis matthewi Barney

new species

9. Pachybrachis matthewi Barney   , new species ( Fig. 9 View Fig , Map 2A)

Holotype. Male , labeled “KY: Trigg Co. / Fort Campbell 41-01 / 36.689156 o N, - 87.686699 o W / 18 June 2008 / R. J. Barney [printed, black on white] // [circular blue disc signifying dissection by RJB] // Pachybrachis   / #30 [hand-written, white paper] / det. E. G. Riley 2009 [printed, white paper] // HOLOTYPE / Pachybrachis   / matthewi   / R. J. Barney 2017 [printed, red paper]”. Deposited in MCZ. The specimen is point-mounted with genitalia affixed to the point. It is in excellent condition with all appendages intact. There are seven paratypes (566 2♀♀) with identical collecting data. GoogleMaps  

Paratypes. 13966 158♀♀. See Appendix 9.

Description. Male. Large, yellow with reduced brown-black maculae; L = 2.07–2.42 mm (mean = 2.18 mm, n = 10); W = 1.10–1.22 mm (mean = 1.17 mm, n = 10); L/W = 1.80–1.92 (mean = 1.87, n = 10). Head: Slightly wider than thoracic apex, HW = 0.73–0.83 mm (mean = 0.77 mm, n = 10); eyes moderately separated, IOD = 0.18–0.26 mm (mean = 0.22 mm, n = 10), IOD/HW = 0.25–0.33 (mean = 0.29, n = 10); face yellow with brown to black, W-shaped macula connecting vertex and bases of antennae and up to base of upper lobes of eyes; punctation dense in black areas, sparser in pale areas; antennae brown to black, reaching elytral declivity ( Fig. 9 View Fig ). Pronotum: Yellow with brown to black, M-shaped macula broad, not sharply defined and usually reduced to fragments; punctation dense in dark areas, more sparsely placed in pale areas, especially along lateral margins; PL = 0.67–0.80 mm (mean = 0.71 mm, n = 10); PW = 0.94–1.12 mm (mean = 1.00 mm, n = 10); PL/PW = 0.68–0.74 (mean = 0.71, n = 10). Elytra: Yellow with brown to black maculae often reduced to 3 small lateral spots and 3 adjacent mid-elytral spots; striae especially confused in basosutural region and incomplete basally, most regular laterally and apically, very little inter-strial punctation ( Fig. 9 View Fig ). Pygidium: Finely punctate, weakly convex; brown to black with large, confluent, oval, yellow maculae occupying majority of surface. Venter: Black, upper sides of last ventrite yellow. Legs: Black with brown and yellow femoral and tibial spots; front claws not distinctly enlarged. Genitalia: Median lobe in enface view very wide, sides parallel to ALM,then gently curved to terminus; pre- and post-orificial lengths negligible, thus OS very large, with large, pigmented basal plates occupying half OS; median lobe in lateral view with inflated base, narrowing to a ridge-like keel at ALA, formed by 2 shallow depressions as seen from sub-en-face view; DEO deflexed at near 60° angle, without denticles or beards ( Fig.9 View Fig ). Fifty-six males from seven states were dissected.

Female. As in male, except L = 2.28–2.67 mm (mean = 2.51 mm, n = 11); W = 1.25–1.44 mm (mean = 1.38 mm, n = 11); L/W = 1.76– 1.86 (mean = 1.82, n = 11); HW = 0.83–0.97 mm (mean = 0.90 mm, n = 11); IOD = 0.26–0.36 mm (mean = 0.30 mm, n = 11).

Etymology. This species is named in recognition of Matthew Robert Barney, Heartland Master PIT Trainer, Frito-Lay North America, Inc., Louisville, Kentucky.

Remarks. Pachybrachis matthewi   is very similar to P. varians   and may eventually be determined to be a more northern variation. Pachybrachis matthewi   is larger than P. varians   , with reduced maculation, greater interspace punctation, and longer antennae. The median lobe of the aedeagus is significantly wider in en-face view, but the overall configuration is very similar ( Figs. 8 View Fig and 9 View Fig ).

Distribution. This species is found in the mid- Mississippi River Valley from Missouri and Kentucky to Oklahoma and Alabama (Map 2A).

Biological Notes. I collected this species on Hypericum dolabriforme Vent.   in Kentucky and on Hypericum spp.   in Oklahoma and Tennessee. Labels also cited potential host plants as Rhus aromatica Aiton   in Kentucky and Apocynum sibiricum Jacq.   (= cannabinum L.) ( Apocynaceae   ) in Illinois.

Specimens Examined. See Appendix 9.