Polyphylla rugosipennis Casey

La Rue, Delbert A., 2016, Natural history, ecology, and conservation of the genus Polyphylla Harris, 1841. 1. New species from the southwestern United States and Baja California, Mexico, with notes on distribution and synonymy (Coleoptera: Scarabaeidae: Melolonthinae), Insecta Mundi 2016 (491), pp. 1-41 : 29-30

Polyphylla rugosipennis Casey

Materials examined. USA, Arizona: Coconino County, Flagstaff, Hwy. 180, 15.VII.1991, E.C. and R.C. Mower (1 male, DALC) ; Mogollon Rim, Hwy 87, 3.3 mi N. of Strawberry , 2000m elev., 1.VIII.1998, MV/ BL, R.A. Cunningham, J.D. Beierl (1 male, DALC) ; Navajo County, Show Low , VIII.1975, no collector (1 male, BYUC) ; East Heber , 12.VII.2003, T.P. Blumer (3 males, BYUC) ; Yavapai County, 17 miles NE Payson, Camp Christopher , at town lights, 6000 ft. el., 1.VIII.1998, R.A. Cunningham Sr. / Jr., J.D. Beierl (3 males, DALC) .

New Mexico: San Juan County, Jct. of Rd. 5577/Rd.5569, 0.5 miles W. of County Rd. 350, 36°43.689N / 108° 05.214W, 18.VI.-06.VII. 2006, T.G. Merrion, MVL (2 males, POKC) ; same locality except labeled 36° 43.682N / 108° 05.231W, various dates between 01.IX.2004 - 26.VI.2005, P.O. Kaufman, MVL (4 males, POKC) .

Utah: Grand County, Sego Canyon, 8 mi N of Thompson Turnoff I-70, Book Cliffs , 13.VII.2006, 6057 ft. elev., T.S. and R.C. Mower (2 males, BYUC) ; Iron County, Kanarraville , 26.VII.2006, K. Miwa (1 male, BYUC) ; Kane County, Grand Staircase-Escalante National Monument, Seaman Spring , off Hwy. 89, 37°06’16”N / 112°15’08”W, 29.VI-10.VII.2001, K.A. Clarke, K.C. Greene (3 males, BYUC) ; Utah County, Lake Mt., Saratoga Springs , 23.VIII.2003, D.E. Haider (1 male, DALC) .

Remarks. Type locality: “ Arizona (Grand Cañon of the Colorado)” Casey (1914).

This species is poorly represented in collections and little is known of its natural history or ecological associations. At present, the known distribution is significantly fragmented being recorded primarily from the Grand Canyon area of northern Arizona and the Sierra San Pedro Martir, Baja California, Mexico ( Hardy 1981; Young 1988). The female remains unknown.

The San Juan County, New Mexico, locality is in an area of Juniperus sp. and Atriplex canescens (Pursh) Nuttall (saltbush: Amaranthaceae ), 1675 m elevation, associated with the Chaco Dune Field in northwestern New Mexico ( Schultz and Wells 1981). Polyphylla decemlineata was sympatric at this locality (P.O. Kaufman, personal communication).

Sego Canyon, Grand County, is in southeast Utah among pinyon-juniper-oak woodlands with scattered to dense stands of Artemisia sp. and Ericameria sp. growing in sandy alluvial soil.

Seaman Spring, Kane County, is in south central Utah in an area of Pinus edulis and Juniperus osteosperma at an elevation of 1870 m.

The combination of dark brown to black dorsal integument; presence of head, pronotal, elytral, and pygidial setae; rough-edged, incomplete elytral vittae; parallel lateral clypeal margins; coarsely punctate pronotal disc; comparatively small antennal structure; and bidentate protibia distinguish males of this species from sympatric congeners: P. arguta , P. decemlineata , P. diffracta , and P. hammondi . Of these, P. rugosipennis is most similar to P. arguta with which it shares a brown to black dorsal integument; white squamal vestiture; elytral vittae linear, whether continuous or fragmented, with edges coarsely eroded; and medium to large size (length usually greater than 25 mm). Polyphylla arguta lacks pronotal and elytral discal setae usually present in P. rugosipennis . However, the presence or absence of pronotal setae in P. rugosipennis is apparently variable ( Casey 1914; Cazier 1938) as is their length either short ( Hardy 1981) or long ( Young 1988). All of the specimens cited here have short pronotal setae. Although male protibial dentition in P. rugosipennis is typically bidentate, one specimen from the Camp Christopher, Yavapai County, Arizona, series is distinctly unidentate without any indication of further dentition or excessive abrasion. Furthermore, the elytral vittae of P. rugosipennis may vary from nearly longitudinally complete to significantly fragmented and discontinuous. As a result of erroneous concepts and perfunctory “gestalt” taxonomy, the latter variation is frequently misidentified as P. diffracta . This variability in intraspecific morphology may possibly contribute to the species’ misidentification and explain its inconsistent distribution.