Stenotothorax mcpeaki Gordon and Skelley

Skelley, Paul E. & McPeak, Ron H., 2018, New species of Stenotothorax Schmidt from the northwestern United States (Coleoptera: Scarabaeidae: Aphodiinae), Insecta Mundi 681, pp. 1-31 : 10-11

Stenotothorax mcpeaki Gordon and Skelley

Figure 25

Stenotothorax mcpeaki Gordon and Skelley 2007: 207–208 .

Diagnosis. Stenotothorax mcpeaki is distinguished from other species in the region by the clypeus lacking teeth and setal fringe, the complete basal pronotal marginal line, and the explanate pronotum. Stenotothorax mcpeaki appears to be restricted to sites near the Columbia River along the Oregon and Washington border, east of the Cascade Mountains. Gordon and Skelley (2007) did not have a male present for the original description. We take this opportunity to describe male characters from topotypic specimens.

Male. Male genitalia with parameres shorter than basal piece, abruptly curved and acutely pointed apically in lateral view (similar to S. smilodon , as in Fig. 41 ). Sexual dimorphism evident in male with short stout lower mesotibial spur, length about 1/3 length of upper spur, with inward apical hook. Male protibia narrower than female.

Type material. Oregon, Wasco Co., 6 mi. E. of The Dalles ( USNM, examined).

Materials studied. (n = 142) Collection data for materials confirmed to be S. mcpeaki are: OREGON: Gillam Co.: John Day River & Rock Creek, 0.5 mi. S. of McDonald, 45°34.858′N, 120°24.378′W, 384 ft, 10-XI-2015, P.E. Skelley, K.E. Schnepp, R.H. McPeak, K. Arguez [2 FSCA, 6 KESC] ; Rock Creek & John Day River, 45°34.858′N, 120°24.378′W, 384 ft, 10-XI-2015 to 1-IV-2016, R.H. McPeak [4 FSCA, 3 RMPC] ; Wasco Co.: 5.2 mi. E. of The Dalles on I-84, 4-XII-2008 to 22-I-2009, R.H. McPeak, [1 RMPC] ; same locality, 22-I to 25-IV-2009, R.H. McPeak [3 RMPC] ; 6 mi. E. of The Dalles , 45°38.847′N, 121°02.454′W, 11-22-III-2005, R.H. McPeak [1 FSCA; [2 RMPC] ; same locality, 14-30-XI-2007, R.H. McPeak [2 FSCA] ; 6 mi. E. of The Dalles eastbound I-84, 45°38.846′N, 121°02.458′W, 7-X-17-XII-2007, R.H. McPeak [1 ODA, 5 RMPC, 2 WBWC] ; same locality, 30-XI-2007 to 19-I-2008, R.H. McPeak [1 ODA, 20 RMPC] ; same locality, 19-I-2008 to 12-IV-2008, R.H. McPeak [1 RMPC] ; same locality, 23-X-19-XI-2011, R. McPeak [5 FSCA] ; same locality, 20-XI-19-XII-2011, P. Skelley, R.H. McPeak [3 CMNC, 2 DCGC, 18 FSCA, 2 NHML, 1 RMPC, 2 WBWC, 2 WSU] ; same locality, 19-XII-2011 to 30-I-2012, R.H. McPeak [10 RMPC] ; 6.3 mi. N. Dufur on Hwy 197, 29-IX-2008, R.H. McPeak [1 RMPC] ; mouth of Deschutes R. at Columbia R., 45°37.757′N, 120°54.822′W, 24-XI-2013 to 10-I-2014, R.H. McPeak [1 RMPC] ; Rufus , 45°41.444′N, 120°44.409′W, 235 ft, 23-IX-2013 to 10-I-2014, R.H. McPeak [3 FSCA, 1 RMPC] ; same locality, 10-I-2014 to 14-XI-2014, R.H. McPeak [1 RMPC] ; The Dalles , nr. Discovery Center, 45°38.912′N, 121°12.699′W, 170 ft, 30-XI-2013 to 10-I-2014, R.H. McPeak [2 RMPC] ; same locality, 10-I-21-II-2014, R.H. McPeak [1 FSCA] ; Tygh Valley , 45°15.404′N, 121°10.529′W, 1196 ft, 8-XI-2013, R.H. McPeak [3 RMPC] ; same locality, 5-IX-2013 to 10-I-2014, R.H. McPeak [10 FSCA, 13 RMPC] ; same locality, 10-I-2014 to 21-XI- 2014, R.H. McPeak [3 RMPC] ; same locality, 11-XI-2014, K.E. Schnepp [1 KESC] .

Washington: Klickitat Co.: Avery Park ; 1.5 mi. E, 45°39.561′N, 121°00.522′W, 200 ft, 20-XI-2011 to 30-I-2012, R.H. McPeak [1 FSCA] ; Dallesport ; 100 m east of Hwy 197, 45°37.604′N, 121°08.825′W, 200 ft, 23-XI-2013 to 10-I-2014, R.H. McPeak [1 FSCA] ; Dallesport ; dunes to NW, 45°38.182′N, 121°11.376′W, 145 ft, 30-XI-2013 to 21-II-2014, R.H. McPeak [1 RMPC] .

Observed habits. Specimens have been collected in barrier pitfall traps in grasslands with many pocket gopher and ground squirrel nests, in sandy areas with sage brush, in Thomomys Wied-Neuwied burrows, from backfilled Thomomys burrows, in ground squirrel burrows, under fresh slimy deer bone, coyote scat, and in sand under dune shrubs.

Remarks. Stenotothorax mcpeaki is most similar to S. smilodon , see remarks under that species.

Figures

Figures 24–29. Stenotothorax species, head and pronotum. 24) S. lanei. 25) S. mcpeaki. 26) S. washtucna. 27) S. woodleyi, typical pronotum. 28) S. woodleyi, from Rufus, OR. 29) S. winnemucca, ventral protibia, female paratype from type locality.

Figures 36–41. Stenotothorax smilodon, n. sp. 36) Dorsal habitus. 37) Ventral habitus. 38) Lateral habitus. 38) Oblique anterior view head to elytral base. 40) Epipharynx. 41) Male genitalia, lateral view.