Pachybrachis snowi Bowditch, 1909

Barney, Robert J., 2023, Redescriptions of the Pachybrachis Chevrolat (Coleoptera: Chrysomelidae: Cryptocephalinae) of Arizona, Including New Synonymies, State Records, Plant Associations, and Descriptions of New Species: The Robust Species, The Coleopterists Bulletin 77 (3), pp. 439-459 : 446-449

9. Pachybrachis snowi Bowditch, 1909 ( Figs. 3 , 4 )

Pachybrachys snowi Bowditch 1909: 290 . Fall 1915: 383 (taxonomy).

Pachybrachis snowi : Riley et al. 2003: 163 (catalog).

Pachybrachys wenzeli Fall 1915: 382 . New synonymy.

Pachybrachis wenzeli : Riley et al. 2003: 165 (catalog).

Type. Bowditch (1909) described P. snowi based upon several specimens from southeastern Arizona. The Bowditch Collection contains three (3♀♀, including one labeled “type [pink paper]”, another “cotype”) from Douglas , three (1♂ 2♀♀) from the Santa Rita Mountains , and ten (4♂♂ 6♀♀, including one male labeled “typical” and one female labeled “suffused var.”) from Prescott. A male from the Santa Rita Mountains , hereby designated lectotype, labeled “ ♂ // Santa Rita Mts. / Ariz. 5 to 8000 ft. / July, F. H. Snow [printed italics, white paper] // [circular blue disc signifying dissection by RJB] // LECTOTYPE / Pachybrachys / snowi Bowditch / R. J. Barney 2023 [printed, red paper]”, was examined, dissected, and photographed ( Fig. 3 ). The remaining specimens referenced above, hereby designated paralectotypes, were given the additional label PARALECTOTYPE / Pachybrachys / snowi Bowditch / R. J. Barney 2023 [printed, yellow paper]” .

Fall (1915) described P. wenzeli based upon many specimens from the mountains of southeastern Arizona. Fall’s type male, hereby designated lectotype, labeled “ ♂ // Huachu. Mts. / Ariz [printed, white paper] // Miller Can / H.A. Wenzel [printed, white paper] // TYPE [printed] / wenzeli [hand-inked, white paper] // M.C.Z. [printed] / 24993 [hand-inked, red paper] // H.C. FALL / COLLECTION [printed, white paper] // [circular blue disc signifying dissection by RJB] // LECTOTYPE / Pachybrachys / wenzeli Fall / R. J. Barney 2023 [printed, red paper]”, was examined, dissected, and photographed ( Fig. 4 ) .

Redescription. Male. Robust, yellow with extensive black maculae; L = 3.37–4.55 mm (mean = 4.09 mm, n = 10); W = 1.86–2.61 mm (mean = 2.34 mm, n = 10); L/W = 1.68–1.86 (mean = 1.76, n = 10). Head: Slightly wider than thoracic apex, HW = 1.25–1.65 mm (mean = 1.48 mm, n = 10); eyes narrowly separated, IOD = 0.14–0.36 mm, (mean = 0.23 mm, n = 10), IOD/HW = 0.10–0.24 (mean = 0.16, n = 10); face yellow with wide, black, W-shaped macula connecting vertex, bases of antennae and upper lobes of eyes; no ocular lines; punctation dense in dark areas, sparser in pale areas; antenna yellow, brown, almost reaching elytral declivity. Pronotum: Yellow-red with black, M-shaped maculae, not sharply defined; punctation dense in dark areas, more sparsely placed in pale areas, extending to lateral margins; PL = 1.01– 1.52 mm (mean = 1.31 mm, n = 10); PW = 1.65– 2.50 mm (mean = 2.17 mm, n = 10); PL/PW = 0.57–0.65 (mean = 0.761 n = 10). Elytra: Yellow with extensive black maculae; striae especially confused in baso-sutural region, most regular laterally and apically, very little inter-strial punctation. Pygidium: Black with yellow-brown maculae. Venter: Black, upper sides of last ventrite yellow. Legs: Yellow with brown and black spots; front claws appreciably enlarged. Genitalia: Median lobe in en-face view wide, oval OS, with extensive PRL and POL, the post-orificial length ending in a triangular DEO; medial lobe in lateral view with inflated, tubular base, narrowing to terminus. Sixteen males from three USA states were dissected.

Female. As in male, except L = 4.26–4.77 mm (mean = 4.60 mm, n = 10); W = 2.43–2.90 mm (mean = 2.67 mm, n = 10); L/W = 1.64–1.82 (mean = 1.72, n = 10); HW = 1.55–1.85 mm (mean = 1.69 mm, n = 10); IOD = 0.22–0.49 mm (mean = 0.38 mm, n = 10); IOD/HW = 0.14–0.31 (mean = 0.23, n = 10).

Remarks. The Bowditch Collection contains 16 specimens (5♂♂ 11♀♀) of P. snowi , which represents most of the specimens Bowditch (1909) cited in his description. Four of the males are from Prescott and one male is from the Santa Rita Mountains. The Santa Rita male was chosen as the lectotype as it is located closer to the Baboquivari Mountains where his designated type female was located. Three of the five males were dissected and all had the same aedeagal median lobe, as pictured in Fig. 3 . What was not expected is that the P. wenzeli specimens in the Fall Collection are in fact P. snowi . While describing P. wenzeli, Fall (1915) noted the external variability of this species ranging from almost entirely black to yellow irrorate with black. A comparison of the aedeagal median lobes of the P. snowi and P. wenzeli lectotypes reveals a difference in scale but the same basic pattern. The lobe of P. snowi is overall larger, longer and wider, and the postorificial length greater. However, upon the examination of many specimens it become difficult to definitely separate specimens into two distinct groups. Pachybrachis snowi is often confused with P. pima . The triangular DEO of P. snowi has extensive POL, while the DEO of P. pima is level with a small extended T.

Distribution. Riley et al. (2003) reported P. snowi from Arizona and P. wenzeli from Arizona, New Mexico, and Texas.

Biological Notes. Clark et al. (2004) reported some specimens of P. wenzeli in Arizona collected from Mimosa ( Fabaceae ) and some in Texas from Quercus ( Fagaceae ). Some Arizona specimens in this study were reportedly collected on Quercus utahensis (A. DC.) Rydb. , Quercus arizonica Sargent , and Senegalia (Acacia) greggii (A. Gray) Britton & Rose ( Fabaceae ). Clark et al. (2004) reported Arizona specimens of P. snowi on A. greggii and Mimosa biuncifera Benth. , and P. wenzeli on Mimosa sp. Pachybrachis wenzeli was also reported on Quercus in Texas. Differences in host plants may have an influence on variations in size and coloring.

Specimens Examined. Lectotype and paralectotypes plus 48 specimens. USA: ARIZONA: Cochise Co., Huachuca Mts., Miller Canyon, H. A. Wenzel [1♂, wenzeli LECTOTYPE, MCZ-FALL]; Chiricahua Mts., 2 mi SW of SWRS, 1,797 m, 31.8738°N 109.2358°W, 25.v.2018, D. J. Cavan [1♂ 1♀, DJCC]; Coconino Co., Williams, 30.vi, Barber and Schwarz [1♂, wenzeli Fall 1915 Revis., USNM ]; 3 mi W of Williams, 31.v.1962, ex Quercus utahensis, G. H. Nelson [4♂♂ 3♀♀, AJGC]; Rt. 17, Willard Springs, 25.v.2013, J. Huether [1♂, BYUC]; Gila Co., Globe, 16.iv.1934, ex Acacia greggii, F. H. Parker [1♂, BYUC]; Pima Co., Santa Rita Mts. , 5–8,000 ft., vii, F. H. Snow [1♂ 2♀♀, MCZ-BOW]; Santa Rita Mts., Madera Canyon , 3.vi.2006, C. W. O’Brien [1♂, BYUC]; Santa Rita Mts. , 17.vi, Barber and Schwarz [1♂, snowi Fall 1915 Revis., USNM ]; Baboquivari Mts., F. H. Snow [1♀, snowi H.C. Fall, USNM ]; Pinal Co., Pinal Mts., 13.v.1945, ex oak, F. H. Parker [2♂♂, FSCA]; Santa Cruz Co., Peña Blanca Canyon , 18.vii.2003, S. M. Clark and R. C. Mower [1♂, BYUC]; Madera Canyon, 5,400 ft., 18–29.vi.1979, F. T. Hovore [1♂, BYUC]; Santa Rita Mts., Madera Canyon , 30.vii.1963, ex Quercus arizonica, G. H. Nelson [1♂ 1♀, FSCA]; same data, except 30.vii.1976 [1♂ 2♀♀, FSCA]; Parker Canyon, 4.vi.1972, K. Stephan [2♂♂ 2♀♀, FSCA]; Chiricahua Mts., 15.vi.1939, D. J. and J. N. Knull [1♂, OSUC]; Yavapai Co., Prescott, vi–vii.1894 [4♂♂ 6♀♀, MCZ-BOW]. TEXAS: Jeff Davis Co., Ft. Davis, 1.vi.1959, ex Quercus sp. , Howden and Becker [1♂ 1♀, RJBC]; Davis Mtn. Resort, 2–3. vi.2001, W. B. Warner [1♂ 1♀, BYUC]. UTAH: Utah Co., Provo Canyon, around Johnson Hole, N of Canyon Glenn Park, 3.vi.2015, J. Quist, B. Allen and D. Allen [1♂ 1♀, DJCC].

Figures

Fig. 3. Pachybrachis snowi, Santa Rita Mountains, Arizona, lectotype. 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.

Fig. 4. Pachybrachis wenzeli, Huachuca Mountains, Arizona, lectotype. 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.