Pachybrachis pallidipennis Suffrian, 1858

Barney, Robert J., 2016, Definition and Revision of theOthonusSpecies-Group of North AmericanPachybrachisChevrolat (Coleoptera: Chrysomelidae: Cryptocephalinae), The Coleopterists Bulletin 70 (3), pp. 569-605 : 569-605

publication ID	https://doi.org/ 10.1649/0010-065X-70.3.569
persistent identifier	https://treatment.plazi.org/id/03A3AA14-CB4C-353D-FD70-A3577F0690B0
treatment provided by	Diego
scientific name	Pachybrachis pallidipennis Suffrian, 1858
status	stat. nov.

Treatment

3. Pachybrachis pallidipennis Suffrian, 1858 , new status ( Fig. 3 View Fig ; Map 1A, B)

Pachybrachys pallidipennis Suffrian 1858: 406 . LeConte 1880: 209 (catalogue); Fall 1915: 450 (taxonomy, catalogue); Knaus 1916–17: 262 (catalogue).

Pachybrachys striatus LeConte 1880: 205 .

Pachybrachis othonus pallidipennis Suffrian : Balsbaugh 1973: 252 (taxonomy); Riley et al. 2003: 161 (catalogue); Clark et al. 2004: 160 (plant associations).

Type Material. Suffrian (1858) cited his type as “From Texas (Mus. Berol.) and the neighborhood of the city of Mexico (Mus. Dohrn)”. A request to MNHUB did not reveal type material. A type specimen received by Edward G. Riley ( TAMU) from Halle ( MLUH), Germany (personal communication) was actually Pachybrachis umbraculatus Suffrian , so the type may no longer be extant, the wrong specimen was sent, or this represents the Mexican type referred to by Suffrian. Fall (1915) apparently studied the Texas type, and Balsbaugh (1973) made no mention of type .

Redescription. Male. Robust, L = 2.50– 2.92 mm (mean = 2.69 mm, n = 10); W = 1.43– 1.62 mm (mean = 1.54 mm, n = 10); L/W = 1.66– 1.79 (mean = 1.74, n = 10). Head: Slightly wider than thoracic apex, HW = 0.92–1.06 mm (mean = 0.99 mm, n = 10); eyes widely separated, IOD = 0.36–0.46 mm (mean = 0.40 mm, n = 10); IOD/ HW = 0.36–0.43 (mean = 0.41, n = 10), face mostly yellow with black, often discontinuous, W-shaped macula connecting the vertex and base of antennae, and up to base of upper lobe of eyes, finely alutaceous and shiny, punctation sparse and widely separated, antennae brown, not reaching elytral declivity. Pronotum: Yellow, pronotal M black with strigose punctures, often mildly separated into 3 parts, PL = 1.28–1.52 mm (mean = 1.42 mm, n = 10); PW = 0.82–1.02 mm (mean = 0.90 mm, n = 10); PL/PW = 1.49–1.63 (mean = 1.58, n = 10). Elytra: Yellow, elytral striae very regular and complete, sutural edges and shoulder club black. Pygidium: Finely punctate, weakly convex; black with large, confluent, oval yellow macula occupying majority of surface. Venter: Black, upper sides of last ventrite yellow. Legs: Yellow. Genitalia: Median lobe in en-face view parallelsided, gently rounded to a much reduced nodule at terminus ( Fig. 3 View Fig ). Orificial space longer than wide with sclerotized basal plates. Primary setal beards forming long, loose wisps at apicolateral margin. In lateral view, ventral surface inflated, without keel, with a continuous bulge from base to near terminus (18 males from seven states were dissected).

Female. As in male, except a few with remnants of vittae, L = 2.95–3.55 mm (mean = 3.21 mm, n = 10); W = 1.65–2.12 mm (mean = 1.88 mm, n = 10); HW = 1.09–1.30 mm (mean = 1.17 mm, n = 10); IOD = 0.49–0.60 mm (mean = 0.54 mm, n = 10); IOD/HW = 0.41–0.50 (mean = 0.46, n = 10).

Remarks. Balsbaugh (1973) relegated P.pallidipennis to a subspecies of P. othonus occurring in semiarid and arid climatic zones. After an examination of 51 specimens from six states and conducting dissections and aedeagal examinations of 16 males, some of them with Balsbaugh’ s 1972 P. othonus sioux identification labels, I have concluded that P. pallidipennis is in fact a legitimate species. The regular elytral striation, and lack of orificial, sclerotized, paired lamellae as in P. othonus , re-establishes species status to P. pallidipennis (see Key). A series of Pachybrachis collected by Balsbaugh at Sentinel Butte, Golden Valley, North Dakota, contained 1♂ pallidipennis and 2♂♂ sioux -like othonus . Another series of 5♂♂ 3♀♀ vittate specimens from Ransom County, North Dakota, bearing P. othonus sioux Balsbaugh identification labels, were found upon dissection to be P. pallidipennis .

Distribution. Pachybrachis pallidipennis is found from Texas and Louisiana to Wyoming and North Dakota (Map 1B). LeConte (1880) cited P. striatus as found in Texas and Kansas.

Biological Notes. Clark et al. (2004) reported this species swept from foliage of Gutierrezia dracunculoides (DC.) Hoffm. and Gutierrezia texana (DC.) Torr. & Gray (Asteraceae) in Bell County, Texas. Plant associations were cited on labels for

Texas specimens on Monarda sp. (Lamiaceae) and Rudbeckia sp. (Asteraceae) .

Specimens Examined. See Appendix 3.

4. Pachybrachis praeclarus Weise, 1913 ( Fig. 4 View Fig ; Map 2B)

Pachybrachys elegans Blatchley 1910: 1127 [not

Graëlls].

Pachybrachys praeclarus Weise 1913: 219

[replacement name for Pachybrachys elegans

Blatchley, 1910]; Fall 1915: 457 (taxonomy,

catalogue); Hughes 1944: 132 (catalogue);

Wilcox 1954: 392 (catalogue).

Pachybrachis praeclarus Weise : Downie and

Arnett 1966: 1318 (taxonomy); Barney 1984:

141 (catalogue, in error); Riley et al. 2003: 162

(catalogue); Clark et al. 2004: 158 (plant asso-

ciations); Barney et al. 2011: 10 (catalogue).

Type Material. Blatchley’ s male holotype of elegans , labeled “Purdue / Blatchley / collection // Marshall Co. / Ind. W.S.B. [printed, white paper] / 6 – 24 – 04 [hand-inked, white paper] // TYPE [printed, red paper] // PERC / 0084351 [printed, green paper]”, was examined via photographs provided by Gino Nearns.

Redescription. Male. Robust, L = 2.89–3.17 mm (mean = 2.99 mm, n = 10); W = 1.61–1.87 mm (mean = 1.74 mm, n = 10); L/W = 1.69– 1.79 (mean = 1.72, n = 10). Head: Slightly wider than thoracic apex, HW = 0.96–1.17 mm (mean = 1.08 mm, n = 10); eyes widely separated, IOD = 0.39–0.57 mm (mean = 0.49 mm, n = 10); IOD/ HW = 0.41–0.48 (mean = 0.46, n = 10); face black, with fine, white pubescence. Pronotum: Broad, very wide basally, strongly narrowed apically; black, moderately shiny, external margins pale yellow, closely, heavily punctured; PL = 1.46–1.76 mm (mean = 1.59 mm, n = 10); PW = 0.77–1.03 mm (mean = 1.08 mm, n = 10); PL/PW = 1.55– 1.88 (mean = 1.69, n = 10). Elytra: Black, moderately shiny, external margins of pale yellow, regularly striate except basally near suture ( Fig. 4 View Fig ). Pygidium: Black. Venter: Black. Legs: Black. Genitalia: Median lobe in en-face view with thickened, parallel sides gently rounding to terminus with small nodule, fine setae visible from across distal en-face outline; in lateral view, median lobe very short and thickened, with setae extending back to sublateral angle (six males from four states were dissected).

Female. As in male, except L = 2.98 – 3.57 mm (mean = 3.39 mm, n = 10); W = 1.66 – 2.16 mm (mean = 1.96 mm, n = 10); HW = 1.02 – 1.30 mm (mean = 1.17 mm, n = 10); IOD = 0.45–0.68 mm (mean = 1.17 mm, n = 10); IOD/ HW = 0.44–0.52 (mean = 0.49, n = 10).

Remarks. This is a very rare and unique species. It may not be morphologically part of the

Map 2. A) Distribution of Pachybrachis nigricornis subspecies based upon specimens examined: P. autolycus (blue), P. carbonarius (black), P. carbonarius yellow (yellow), P. difficilis (green), P. nigricornis (purple), and P. wahsatchensis (grey). B) Distribution of P. nigricornis (black circles) and P. praeclarus (orange diamonds) based upon specimens examined.

nigricornis species-group; however, it can be confused with the yellow form of P. nigricornis carbonarius , as per Barney (1984).

Distribution. Five new state records were discovered: Iowa, Kentucky, Minnesota, Wisconsin, and Wyoming. Specimens from Wyoming to Manitoba, southeast into Missouri and Kentucky were examined (Map 1B).

Biological Notes. No references to habitats or plant associations were found on labels. However, I collected 17 specimens in two state nature preserves in Kentucky: Crooked Creek Barrens (oak barrens community) and Blue Licks Battlefield. Blatchley (1910) reported it beaten from hazel ( Hamamelis sp. , Hamamelidaceae ) in Indiana. A specimen was collected by a flight intercept trap in an oak savanna in Wisconsin.

Specimens Examined. See Appendix 4.

5. Pachybrachis nigricornis (Say), 1824 ( Figs. 5 View Fig , 6A–E View Fig ; Map 2A, B)

Cryptocephalus nigricornis Say 1824: 436 .

Pachybrachys carbonarius Haldeman 1849: 260 ; LeConte 1880: 207 (taxonomy, catalogue); Castle and Laurent 1896: 300 (catalogue); Wickham 1896: 156 (catalogue); Blatchley 1910: 1125 (taxonomy, catalogue); Knaus 1916–1917: 263 (catalogue); Hughes 1944: 132 (catalogue); Wilcox 1954: 393 (catalogue). New synonymy.

Pachybrachis carbonarius Haldeman : Melsheimer 1853: 126 (catalogue); Mombert 1869: 544 (catalogue).

Pachybrachys nigricornis (Say) : LeConte 1880: 209 (catalogue); Fall 1915: 460 (taxonomy, catalogue); Knaus 1916–1917: 262 (catalogue).

Pachybrachys autolycus Fall 1915: 458 ; Knaus 1916–17: 262 (catalogue); Whelan 1936: 114 (catalogue); Wilcox 1954: 392 (catalogue). New synonymy.

Pachybrachys autolycus var. difficilis Fall 1915: 459 . New synonymy.

Pachybrachys autolycus var. wahsatchensis Fall 1915: 459 . New synonymy.

Pachybrachys carbonarius, var. janus Fall 1915: 462 . New synonymy.

Pachybrachis nigricornis nigricornis (Say) : Downie and Arnett 1966: 1318 (taxonomy); Balsbaugh and Hays 1972: 37 (catalogue); Balsbaugh and Tucker 1976: 119 (taxonomy); Riley et al. 2003: 160 (taxonomy, catalogue); Clark et al. 2004: 159 (plant associations); Ciegler 2007: 179 (taxonomy); Barney et al. 2013: 121 (taxonomy). New synonymy.

Pachybrachis nigricornis carbonarius Haldeman : Downie and Arnett 1966: 1318 (taxonomy); Balsbaugh and Hays 1972: 38 (catalogue); Balsbaugh and Tucker 1976: 121 (taxonomy);

Barney 1984: 141 (catalogue); Riley et al. 2003:

160 (taxonomy, catalogue); Clark et al. 2004:

159 (plant associations); Ciegler 2007: 180 (tax-

onomy); Barney and Hall 2009: 467 (taxonomy,

plant associations). New synonymy.

Pachybrachis nigricornis difficilis Fall : Downie

and Arnett 1966: 1318 (taxonomy); Balsbaugh

and Tucker 1976: 121 (taxonomy); Riley et al.

2003: 160 (taxonomy, catalogue); Clark et al.

2004: 159 (plant associations). New synonymy. Pachybrachis nigricornis autolycus Fall : Balsbaugh

and Tucker 1976: 122 (taxonomy); Barney 1984:

137 (catalogue); Riley et al. 2003: 160 (taxon-

omy, catalogue); Clark et al. 2004: 158 (plant

associations). New synonymy.

Type Material. Say’ s holotype of Pachybrachis nigricornis (Say) , reported as from “ Missouri ”, is not extant (Weiss and Ziegler 1931). A male neoparatype in the SDSU, labeled “Boulder, COLO. / 5 mi. S, 5800’ / June 5 1961 / B. H. Poole [printed, white paper] // CRYPTOCEPHALUS / nigricornis Say 1823 (1824) / Designated by / E. U. Balsbaugh, Jr. 1974 [printed, red paper] // SMIRCO117874”, was dissected for aedeagal characteristics and photographed ( Figs. 5 View Fig , 6A View Fig ). The female neotype that Balsbaugh and Tucker (1976) deposited in the CNC, bearing the exact same label as above, was examined via photographs provided by Douglas Hume ( CNC) .

A male type of Pachybrachis carbonarius Haldeman in the LeConte Collection, labeled “[pink circular disc] // Type / 8404 [printed, red paper] // P. carbonarius / Hald. [hand-inked, white paper] // Jan. – Jun. 2001 / MCZ Image / Database // MCZ – ENT / 00008404”, was examined and photographed ( Fig. 6B View Fig ). Fall (1915) made no mention of the holotype. The female holotype of Pachybrachys carbonarius var. janus Fall , labeled “ ♀ // Neb // H. C. FALL / COLLECTION // M.C.Z. / Type / 24947 // Type c. / janus [hand-inked, white paper] // Jan. – Jul. 2006 / MCZ Image / Database”, was examined.

The male holotype of Pachybrachis autolycus , labeled “ ♂ // Meade / Ks. / 6| 12| 03 [hand-inked] // TYPE autolycus [hand-inked, white paper] // H. C. FALL / COLLECTION // M.C.Z. / TYPE / 24916 [printed, red paper] // Jan. – Jul. 2006 / MCZ Image / Database”, was examined and photographed ( Fig. 6E View Fig ). The male holotype of Pachybrachis autolycus var. difficilis , labeled “Tyngsboro / Ms. 7|15|00 // ♂ // N. B. II. / p. 197. // 102 [hand-inked red, white paper] // TYPE / v. / difficilis [hand-inked, white paper] // M.C.Z. / TYPE / 24931 [printed, red paper] // H. C. FALL / COLLECTION // Jan. – Jul. 2006 / MCZ Image / Database ”, was examined and photographed ( Fig. 6C View Fig ). The male holotype of Pachybrachis autolycus var. wahsatchensis , labeled “ Wasatch / 6.27 Ut // ♂ // TYPE / wahsatch / ensis [handinked, white paper] // M.C.Z. / TYPE / 24992 [printed, red paper] // H. C. FALL / COLLEC- TION // Jan. – Jul. 2006 / MCZ Image / Database”, was examined and photographed ( Fig. 6D View Fig ) .

Redescription. Male. Highly variable, ranging from entirely black to mostly yellow, L = 2.09– 2.48 mm (mean = 2.28 mm, n = 10); W = 1.18– 1.39 mm (mean = 1.26 mm, n = 10); L/W = 1.73–1.98 (mean = 1.81, n = 10). Head: Slightly wider than thoracic apex, HW = 0.79–0.95 mm (mean = 0.85 mm, n = 10); eyes widely separated, IOD = 0.32–0.45 mm (mean = 0.37 mm, n = 10); IOD/HW = 0.40–0.48 (mean = 0.44, n = 10). Pronotum: Highly variable, ranging from entirely black to obscurely margined with rufous to yellow with moderate to broad, sharply defined, black M, the lateral vittae rarely disconnected from the median one; PL = 1.03–1.28 mm (mean = 1.13 mm, n = 10); PW = 0.67–0.85 mm (mean = 0.73 mm, n = 10); PL/PW = 1.41–1.64 (mean = 1.55, n = 10). Elytra: Highly variable, ranging from entirely black to obscurely margined with rufous to appearing black with subsutural vitta and yellow margin to yellow with each elytron with 2 discal vittae (often reduced or broken) and black suture ( Figs. 5 View Fig , 6 View Fig A-E). Pygidium: Highly variable, ranging from entirely black to mostly yellow. Venter: Highly variable, ranging from entirely black to mostly yellow. Legs: Highly variable, ranging from entirely black to mostly yellow. Genitalia: Median lobe en-face view widest above midpoint, gently rounded to nodule at terminus. Orificial space longer than wide, with lightly sclerotized basal plates. Setal beard short and fine, extending from widest point of median lobe to terminus. In lateral view, a straight line can be drawn from terminus to basal constriction, orificial side much inflated and curved ( Fig. 5 View Fig ) (93 males from 25 states were dissected).

Female. As in male, except L = 2.54– 3.03 mm (mean = 2.82 mm, n = 10); W = 1.42– 1.70 mm (mean = 1.56 mm, n = 10); HW = 0.91–1.09 mm (mean = 1.02 mm, n = 10); IOD = 0.44–0.57 mm (mean = 0.51 mm, n = 10); IOD/ HW = 0.45–0.53 (mean = 0.50, n = 10).

Remarks. As noted above, all types were examined and photographed. Specimens from the same or similar locations as the types, often from the same collection event and externally appearing identical, were dissected for aedeagal characteristics. Additionally, over 90 specimens from 25 states, representing the range of external diversity described above, were dissected. Included in this aedeagal analysis were representatives from at least three states where the vittate ( P. autolycus ) and entirely black ( P. carbonarius ) forms were present at the same place and time (often in same sweep samples, personal observation) on multiple occasions and years. While subtle aedeagal variation was detected, no consistency was observed to be associated with external appearance (subspecies).

To test this even further, a “blind” aedeagal association exercise was conducted. En-face and lateral views of five aedeagal specimens from each of four former subspecies ( P. nigricornis autolycus , P. nigricornis carbonarius , P. nigricornis difficilis , and P. nigricornis nigricornis ) were printed on a full sheet of paper. The 20 sheets were randomly laid out on a table, and I and an associate independently attempted to sort them solely based upon aedeagal photographs, there being no external beetle photos present (blind). Some grouping of aedeagi was attained, with one group appearing shorter and rounder, another relatively longer and thinner. However, once the photographs were identified, each of the four subspecies was represented in each group. We concluded that even though the beetles could be easily separated by external appearance, there was no consistent aedeagal differentiation. Therefore, P. nigricornis autolycus Fall , P. carbonarius Haldeman , P. nigricornis difficilis Fall , P. nigricornis nigricornis (Say) , P. carbonarius janus Fall , and P. autolycus wahsatchensis Fall are all synonymized with P. nigricornis (Say) .

Distribution. Pachybrachis nigricornis is relatively common across eastern North America (Map 2B). Mapping the former subspecies (Map 2A) demonstrated the lack of any pattern, which Balsbaugh and Tucker (1976) acknowledged.

Biological Notes. Clark et al. (2004) reported several potential plant associations from the literature for various P. nigricornis subspecies, and the following were indicated on labels in this study: P. nigricornis autolycus on Desmodium sp. (Fabaceae) in Illinois; P. nigricornis carbonarius on Fragaria sp. (Rosaceae) in Ontario, Quercus sp. (Fagaceae) in Alabama and Arkansas, Salix sp. (Salicaceae) in Idaho, and Rhus glabra L. ( Anacardiaceae ) in Illinois; and P. nigricornis nigricornis on Euphorbia esula L. ( Euphorbiaceae ) in North Dakota and Senecio sp. (Asteraceae) in Alabama. Barney et al. (2013) reported potential host plant records on labels for P. nigricornis on Cassandra calyculata (L.) D. Don ( Ericaceae ) and Potentilla simplex Michx. (Rosaceae) . Barney and Hall (2009) confirmed that black and yellowmargined P. nigricornis carbonarius in Kentucky feed on the legumes Desmodium paniculatum (L.) DC. and Lespedeza virginica (L.) Britton ( Fabaceae ). Label data indicates specimens were collected in barrens, glades, and hill prairies, and in Malaise traps and night sweeping.

Specimens Examined. See Appendix 5 (a ‘Y’ designates that the specimens were the yellow-margined P. nigricornis carbonarius as described by Barney and Hall 2009).