Pachybrachis luctuosus Suffrian, 1858

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 : 24-25

7. Pachybrachis luctuosus Suffrian, 1858 ( Figs. 7 , 22D–E , Map 1C)

Pachybrachys luctuosus Suffrian 1858: 401 .

Pachybrachis luctuosus: Fall 1915: 425 (catalogue); Downie and Arnett 1996: 1317 (catalogue); Balsbaugh and Hays 1972: 35 (taxonomy); Riley et al. 2003: 159 (catalogue); Clark et al. 2004: 158 (plant associations); Ciegler 2007: 179 (taxonomy); Barney et al. 2013: 118 (taxonomy).

Pachybrachys carolinensis Bowditch 1910: 55 . New synonymy.

Pachybrachis carolinensis: Fall 1915: 425 (catalogue); Fattig 1948: 10 (regional species list); Downie and Arnett 1996:1316 (catalogue); Kirk 1970: 86 (regional species list); Riley et al. 2003: 156 (catalogue); Ciegler 2007: 177 (taxonomy).

Type Material. Fall (1915) based his interpretation of Suffrian’ s P. luctuosus upon “doubtless a genuine type or cotype” male loaned to Bowditch from the Halle Museum. I was able to examine, photograph, and dissect a male from MNHUB labeled “53956 // Zool Mus. / Berlin [printed, white paper] // Pachybrachis / luctuosus / n.8. (Suffr) [hand-inked, white paper] // Hist.- Coll. ( Coleoptera ) / Nr. 53956 / Pachybrachis / luctuosus Suffr. / Patria? Collect. Schaum. / Zool. Mus. Berlin [printed, green paper lined-border] // SYNTYPUS / Pachybrachis / luctuosus Suffrian, 1858 / labeled by MNHUB 2013 [printed, red paper]” ( Fig. 22D ). In Suffrian’ s (1858) description, he references both male and female characteristics of specimens examined from Georgia in the Gerhardt Collection. Therefore, I am unable to definitively designate this specimen as lectotype.

Bowditch’ s female type of P. carolinensis , herein designated paralectotype and labeled “ ♀ // Southern Pines / 7/9/08 [hand-inked] N.C. / A. H. Manee // P. / carolinensis [hand-inked, white paper] // Type ♀ [hand-inked, white paper] // TYPE / F. C. B. Coll. [printed, pink paper] // Type 8788 [hand-inked, red paper] // PARALECTOTYPE 8788 / Pachybrachys / carolinensis Bowditch 1910 / R. J. Barney 2017 [printed, red paper]”, was examined and photographed. Bowditch’ s male cotype of P. carolinensis , herein designated lectotype and labeled “6 // Southern Pines / 6/17/08 [hand-inked] N.C. / A. H. Manee // Type 6 [hand-inked, white paper] // TYPE / F. C. B. Coll. [printed, pink paper] // MCZ-ENT00596894 [QR code] // LECTOTYPE / Pachybrachys / carolinensis Bowditch 1910 / R. J. Barney 2017 [printed, red paper]”, was examined, photographed, and dissected ( Fig. 22E ). I also examined 17 (566 12♀♀) cotypes with identical labels to the lectotype, with label dates from 6/17/08 to 7/20/08 (MCZ-BOW), and herein designate them paralectotypes “[PARALECTOTYPE / Pachybrachys / carolinensis Bowditch 1910 / R. J. Barney 2017 [printed, red paper]” .

Redescription. Male. Varying from primarily black with yellow markings to predominately yellow with standard black maculae, L = 1.75–2.07 mm (mean = 1.94 mm, n = 14); W = 0.95–1.09 mm (mean = 1.04 mm, n = 14); L/ W = 1.75–2.03 (mean = 1.87, n = 14). Head: Slightly wider than thoracic apex, HW = 0.65–0.81 mm (mean = 0.73 mm, n = 14); eyes moderately separated, IOD = 0.18-0.30 mm (mean = 0.23 mm, n = 14), IOD/HW = 0.30–0.39 (mean = 0.32, n = 14); face yellow with large dark brown to black, W-shaped macula connecting vertex and bases of antennae and up to base of upper lobe of eyes, punctation dense in dark areas which may be extensive, antennae yellowbrown, not reaching elytral declivity. Pronotum: Yellow, with dark brown to black, M-shaped macula narrowly to broadly diffuse, punctation dense in dark areas, more sparsely placed in pale areas, especially along lateral margins, PL = 0.57–0.72 mm (mean = 0.64 mm, n = 14); PW = 0.83–1.02 mm (mean = 0.91 mm, n = 14); PL/PW = 0.63–0.76 (mean = 0.70, n = 14). Elytra: Yellow with dark brown to black maculae much reduced, varying to appearing almost black; punctation confused only in basosutural region, striae deep and mostly regular. Pygidium: Finely punctate, weakly convex; dark brown to black, pale version having 2 oval, yellow maculae. Venter: Dark brown to black, yellow spot on last ventrite. Legs: Yellow with brown to black femoral and tibial spots. Genitalia: Median lobe in en-face view with a large, oval OS with shaft widest near midpoint, with reduced pre-orificial length (PRL). POL, best seen in lateral view, with ALA deflexed 90°, thereby creating a diamond-shaped (O) area ( Fig. 7G ), with setae on the rounded ALM, EFW = 0.20–0.24 mm (mean = 0.22 mm, n = 14); AAM = 0.07–0.09 mm (mean = 0.08 mm, n = 14); AAL = 0.06–0.07 mm (mean = 0.07 mm, n = 14); AAW = 0.08–0.10 mm (mean = 0.09 mm, n = 14); AAL/AAW = 0.60–0.80 (mean = 0.71, n = 14). Forty-four males from 19 states and provinces were dissected.

Female. As in male, except L = 1.96–2.26 mm (mean = 2.15 mm, n = 12); W = 1.08–1.26 mm (mean = 1.17 mm, n = 12); L/W = 1.74– 1.90 (mean = 1.84, n = 12); HW = 0.73– 0.88 mm (mean = 0.81 mm, n = 12); IOD = 0.22–0.37 mm (mean = 0.30 mm, n = 12).

Remarks. Historically, few if any specimens were identified in collections as P. luctuosus or P. carolinensis . In Fall’ s (1915) discussion of P. luctuosus , he states that “This species is closely related to carolinensis , and I would not be surprised if the latter were only a paler form of Suffrian’ s species”. A comparison of the median lobe of the aedeagus confirmed Fall’ s speculation, as is usually the case.

In general terms, this species tends to be slightly smaller and darker in the northern USA and larger and paler in the South. The diamond-shaped terminus of the median lobe is very unique among Pachybrachis species in the eastern USA. No significant differences were found in a comparison of five median lobe measurements (EFW, AAM, AAL, AAW, and AALK/AAW) between seven predominately yellow ( P. carolinensis ) and seven predominately black ( P. luctuosus ) specimens.

Distribution. This species is found as far north as Michigan to Québec and to the southern states of Alabama and Florida (Map 1C). New state records are confirmed for 13 states and provinces: Ontario, Québec, Florida, Indiana, Maine, Massachusetts, Michigan, Mississippi, New Jersey, New York, Ohio, Pennsylvania, and West Virginia.

Biological Notes. Pachybrachis luctuosus was cited on labels as collected from pine ( Pinaceae ) in Ontario, Pinus sp. in Maryland, Pinus resinosa Aiton in Québec, Pinus virginiana Mill. in Alabama, and Pinus banksiana Lamb. in New York. Malaise, windowpane, and blacklight traps were reported as collection methods on some labels.

Specimens Examined. See Appendix 7.

Figures

Fig. 7. Pachybrachis luctuosus, syntype. 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.

Fig. 22. Pachybrachis species types, dorsal habitus. A) P. infaustus (female lectotype), B) P. atomus (female paralectotype), C) P. vestigialis (male lectotype), D) P. luctuosus (possible male syntype), E) P. carolinensis (male lectotype), F) P. tybeensis (male lectotype).