Pachybrachis walteri 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 : 38

16. Pachybrachis walteri Barney , new species Zoobank.org/ urn:lsid:zoobank.org:act:96680F60-E8DF-480D-9CCD-F89372681BB0 ( Fig. 16 , Map 3A)

Holotype. Male, labeled “FLA.: HIGHLANDS CO. / ARCHBOLD BIOL. STA. / 5-IX-1979 / H. V. WEEMS, Jr. / THOMAS A. WEBBER / INSECT FLIGHT TRAP [printed, white paper] // [circular blue disc signifying dissection by RJB] // HOLOTYPE / Pachybrachis / walteri / 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 three paratypes (266 1♀) with identical collecting data.

Paratypes. 3766 22♀♀. See Appendix 16.

Description. Male. Yellow, with rufous to dark brown punctures, standard maculae diffuse; L = 2.07– 2.42 mm (mean = 2.26 mm, n = 10); W = 1.06–1.26 mm (mean = 1.20 mm, n = 10); L/W = 1.80–1.97 (mean = 1.88, n = 10). Head: Slightly wider than thoracic apex, HW = 0.68–0.82 mm (mean = 0.77 mm, n = 10); eyes closely separated, IOD = 0.11–0.19 mm (mean = 0.16 mm, n = 10); IOD/HW = 0.16–0.24 (mean = 0.21, n = 10); face yellow with large rufous to dark brown, W-shaped macula connecting the vertex and bases of antennae and up to base of upper lobe of eyes, punctation dense in dark areas, antennae yellow-brown, not reaching elytral declivity. Pronotum: Yellow, with rufous to dark brown, M-shaped macula broadly diffuse, punctation dense in dark areas, generally reaching lateral margins, PL = 0.69–0.80 mm (mean = 0.77 mm, n = 10); PW = 0.92–1.06 mm (mean = 1.00 mm, n = 10); PL/PW = 0.76–0.82 (mean = 0.77, n = 10). Elytra: Yellow with rufous to dark brown maculae in no particular pattern; punctation confused in basosutural region, striae incomplete basally, mostly regular laterally and apically. Pygidium: Finely punctate, weakly convex; rufous to dark brown, with 2, often imperceptible, oval, yellow maculae. Venter: Rufous to dark brown. Legs: Rufous to dark brown to black with yellow femoral and tibial spots. Genitalia: Median lobe in en-face view with large, oval OS with shaft widest at ALM, with reduced PRL. POL, best seen in lateral view, deflexed at near 90° ALA, thereby creating a triangular, arrowhead-shaped area with a gently rounded terminus and 2 posteriorly projecting, rounded denticles. Arrowhead in dorsal view with a third, middle denticle and conspicuous setae on rounded ALM and lateral edges of arrowhead-shaped area ( Fig. 16 ). EFW = 0.30–0.35 mm (mean = 0.33 mm, n = 10); AAM = 0.16–0.19 mm (mean = 0.18 mm, n = 10); AAL = 0.14–0.19 mm (mean = 0.18, n = 10); AAW = 0.15–0.18 mm (mean = 0.17 mm, n = 10); AAL/AAW = 0.81–1.18 (mean = 1.06, n = 10). AAL/AAW ca. 1.0 indicates arrowhead essentially an equilateral triangle.Twenty males from two states were dissected.

Female. As in male, except L = 2.09–2.33 mm (mean = 2.24 mm, n = 7); W = 1.15–1.27 mm (mean = 1.22 mm, n = 7); L/W = 1.76–1.93 (mean 1.83, n = 7); HW = 0.73–0.82 mm (mean = 0.79 mm, n = 7); IOD = 0.16–0.21 mm (mean = 0.18 mm, n = 7); IOD/HW = 0.18–0.26 (mean = 0.23, n = 7). This is one of the few species of Pachybrachis that I have encountered in which the females are not significantly larger than the males.

Etymology. This species is named in honor and posthumous recognition of Walter Bolich Barney, formerly of Louisville, Kentucky.

Remarks. Pachybrachis walteri has a very wide aedeagal median lobe with a distinctive, very large arrowhead-shaped POL, as does P. mcmeansi . 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 only found in Florida and Georgia (Map 3A).

Biological Notes. Many specimens were caught in Malaise traps and insect flight traps in sand pine-oak scrub, longleaf pine-saw palmetto, rosemary scrub, and longleaf pine-turkey oak habitats.

Figures

Fig. 16. Pachybrachis walteri, 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.