Pachybrachis texasensis, Barney, 2021

Barney, Robert J., 2021, Definition and Revision of the cylindricus Species-Group of North American Pachybrachis Chevrolat (Coleoptera: Chrysomelidae: Cryptocephalinae), Including Descriptions of Six New Species, The Coleopterists Bulletin 75 (4), pp. 723-748 : 734

6. PACHYBRACHIS texASeNSIS Barney , new species zoobank.org/ urn:lsid:zoobank.org:act:5A50D4DF-3338-4188-B8CE-67B9F72E08F0 ( Figs. 6 , 14A )

Holotype. Male labeled “ USA: TEX: Grayson Co. /Juniper Point Campground/ 33.85962°N 96.83010°W / IV-27-2012, E. Riley, UV [printed, white paper]//[circular pink disc signifying dissection by E. G. Riley]// Pachybrachis /sp.# 42 [hand-inked]/ Det. E.G.Riley, 2012 [printed, white paper]// HOLOTYPE / Pachybrachis / texasensis Barney /R. J. Barney 2021 [printed, red paper]”. Deposited in MCZ. It is in excellent condition with all appendages intact.

Paratypes. Two specimens (1♂ 1♀) are labeled “ PARATYPE / Pachybrachis / texasensis Barney /R. J. Barney 2021 [printed, yellow paper]” .

Description. Male. Large, black or fuscous and yellow maculate ( Fig. 6 ); L = 3.61–3.71 mm (mean = 3.66 mm, n = 2); W = 1.96–2.31 mm (mean = 2.14 mm, n = 2); L/W = 1.56–1.89 (mean = 1.72, n = 2). Head: Not wider than thoracic apex, HW = 1.25– 1.34 mm (mean = 1.30 mm, n = 2); eyes widely separated, without ocular lines, IOD = 0.36–0.39 mm (mean = 0.37 mm, n = 2); IOD/HW = 0.28–0.29 (mean = 0.29, n = 2); face yellow with large, brown macula descending from the vertex and between the upper lobes of eyes, punctation dense in dark areas, antennae progressing from yellow to brown to apical black, not reaching elytral declivity. Pronotum: Yellow with broad, diffuse M-shaped black macula, densely punctate, less so at margins and median line, strongly narrowed apically; PL = 1.16–1.18 mm (mean = 1.17 mm, n = 2); PW = 1.69—1.77 mm (mean = 1.73 mm, n = 2); PL/PW = 0.67–0.68 (mean = 0.68, n = 2). Elytra: Yellow with standard black maculae, densely punctate in baso-sutural area, striae irregular. Pygidium: Dark brown with 2 oval conjoined yellow spots. Venter: Dark brown with yellow side and apical margins. Legs: Yellow with brown spots, front claws of male greatly enlarged. Genitalia: Median lobe in en-face view shows large, oval OS, with a wide, projecting terminus, bounded on each side with large wisps at the ALM. The lateral view reveals a large, rounded keel, projecting from the base to the initiation of the wisps. Two males from two USA states were dissected.

Female. As in male, except L = 3.93 mm (n = 1); W = 2.08 mm (n = 1); L/W = 1.89 (n = 1); HW = 1.50 mm (n = 1); IOD = 0.56 mm (n = 1); IOD/HW = 0.37 (n = 1).

Etymology. This species is named for the state of Texas, where the holotype was found.

Remarks. Superficially, P. texasensis is easily confused with P. turgidicollis and other species in this group. However, the large, rounded, extended keel of the median lobe allows separation of species.

Distribution. A pair of specimens were found in Texas and a singleton male on a hill prairie above the Mississippi River in Illinois ( Fig. 14A ).

Specimens Examined. Holotype + 2 paratypes. USA: ILLINOIS: Monroe Co., Fults Hill Prairie Nature Preserve, 4 mi SE of Fults, 12.iv.1981, R. J. Barney [1♂, EGR#42 , RJBC]. TEXAS: Grayson Co. , Juniper Point Campground, 33.85962°N 96.83010°W, UV, 27.iv.2012, E. G. Riley [1♂, HOLOTYPE, 1♀, RJBC].

Figures

Fig. 6. Pachybrachis texasensis, new species, Grayson Co., Texas, 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, sub view.

Fig. 14. Distribution of Pachybrachis species, based only upon specimens examined in this study. A) P. hybridus (black), P. turgidicollis (red), P. texasensis, new species (green), P. chaoticus (blue), P. pinguescens (orange), P. crassus (purple), B) P. saguaro, new species (black), P. peninsularis (purple), P. cylindricus (red), P. huachuca, new species (orange), P. hurricane, new species (gray), P. ephedra, new species (blue), and P. ashfork, new species (green).