Stenotothorax lanei (Saylor)

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 : 7-10

Stenotothorax lanei (Saylor)

Figure 24

Aphodius lanei Saylor 1940: 103 ~ Hatch 1971: 448.

Aphodius (Stenotothorax) lanei Saylor ~ Dellacasa 1988: 397.

Stenotothorax lanei (Saylor) ~ Gordon and Skelley 2007: 204–206.

Aphodius caseyi Saylor 1940: 104 ~ Hatch 1971: 447; Gordon and Skelley 2007: 204–206 (syn.).

Aphodius (Stenotothorax) caseyi Saylor ~ Dellacasa 1988: 397.

Aphodius pullmani Saylor 1940: 104 ~ Hatch 1971: 477; Gordon and Skelley 2007: 204–206 (syn.).

Aphodius (Stenotothorax) pullmani Saylor ~ Dellacasa 1988: 397.

Diagnosis. Stenotothorax lanei is distinguished from other members of the genus by the following combination of characters: protibia with secondary setal row, pronotum broad but not laterally explanate, pronotal basal line and bead distinct across width, pronotal lateral marginal bead distinctly thickened anteriorly, elytral humerus rounded to weakly angulate not dentate, and dorsally with fine indistinct punctation on a glossy surface. Stenotothorax lanei appears to be restricted to Blue Mountain area of northeastern Oregon, southeastern Washington, crossing into western Idaho near Moscow.

Redescription. Length 8.6–11.2 mm, width 3.7–5.0 mm. Body elongate, color dark red-brown, glossy. Head with clypeus broad, distance anterior most point of clypeal margin greater than distance from apex to frontoclypeal suture. Clypeus anterior margin distinctly emarginated at middle, rounded on either side; setal fringe absent; surface rugosely wrinkled or weakly granulate anteriorly, becoming smooth along frontoclypeal suture; entire surface from clypeus to vertex with distinct evenly distributed fine punctures; vertex with few widely scattered coarse punctures each side of middle; frontal lobe projecting, weakly angulate. Epipharynx with apical margin sinuate, tylus projecting; chaetopedia few and stout; epitorma narrowed (fig. 381 in Gordon and Skelley 2007). Pronotum broad, transversely rectangular in dorsal view, widest at middle, glossy; with evenly distributed indistinct fine punctures; coarse punctures widely scattered, diameter = width of basal marginal groove, about 10 x larger than fine punctures, not denser laterally, occasionally absent along anterior medial surface; surface near anterior angles not explanate; lateral margins evenly arcuate anteriorly, becoming broadly rounded posteriorly, lacking setal fringe; posterior angle rounded, weakly evident; lateral marginal bead notably thickened on anterior half; basal groove broad and bead distinct, not reduced, present on either side of middle when viewed dorsally, continuous with lateral groove and bead. Scutellum triangular, coarsely punctate basally, lacking punctures apically. Elytra fused, elongate; each humerus rounded, humeral denticle lacking; sides evenly arcuate to weakly pointed apex; elytral punctation obscure, surface glossy; striae all similar in development, fine; sides smoothly rounded, striae not more distinct nor wider basally, slightly wider and deeper over posterior declivity; striae I–VI reaching base; strial punctures fine but distinct and weakly crenating sides; intervals weakly convex, all similarly developed; epipleural fold setose at extreme base only. Appendages with hind wing vestigial, strap-like. Profemur densely coarsely punctate on ventral surface. Protibia elongate, primary dorsal setal row situated along midline; with a secondary row of setae; lateral teeth with basal most tooth situated at mid-tibial length; protibial spur evenly curved inwardly; protibia lacking ventral projections at medial apex beneath spur and ventrally along basal median margin; lacking coarse punctations on ventral surface. Meso- and metafemur finely punctate on ventral surface, coarse punctures few, less distinct than profemur. Meso- and metatibia gradually widening before abruptly dilated apex. Meso- and metatibial spurs narrowed, saber-like; lower mesotibial spur sexually dimorphic. Meso- and metatarsomere I length = length of corresponding upper spur. Venter with metasternum short; densely coarsely punctate laterally, sparsely finely punctate medially. Abdomen with basal sternite coarsely punctate, setose and rugose across surface; medial and apical sternites punctate as basal sternite laterally, glossy and impunctate medially. Male genitalia with parameres longer than basal piece, weakly curved lateral view, apex dorsoventrally flattened and rounded (fig. 392 in Gordon and Skelley 2007).

Sexual dimorphism. Male protibial spur bent more abruptly inward in apical 1/3; female more evenly curved from middle. Lower mesotibial spur of male stout, short, 1/3 length of upper spur, bent inward at apex; female lower mesotibial spur unmodified, 1/2 length of upper spur.

Variation. Some specimens of S. lanei show striking amounts of wear on various body parts. The potential for character reductions need to be realized when observing worn specimens. Examples of this wear includes near loss of protibial teeth, near loss of clypeal rugosity (type of A. pullmani ), and even dulling of the surface. Variation in punctation and other characters led to Saylor placing his species in different sections of his key. The truncation of the apical protibial tooth (type of A. caseyi ), is partially sexually dimorphic, but not entirely, and is the most readily worn structure. Thus, this is not a good character to use in species recognition. Most specimens studied have a similar number of coarse pronotal punctures, but some have notably less or more.

The holotype of S. lanei and one other from Whitman Co., Washington, are the only specimens studied that have greatly reduced basal pronotal line. Both are the only specimens known from each locality. However, available specimens from areas surrounding these localities all possess a distinct basal line of varying degrees of development. All other diagnostic characters are shared with other specimens.

Type material. Of A. lanei , Washington, Blue Mts., Godman Spr., 6000′ ( USNM, examined); of A. caseyi , Oregon ( USNM, examined); of A. pullmani , Washington, Pullman ( USNM, examined).

Materials studied. (n = 63) Collection data for materials confirmed to be S. lanei are: IDAHO: Latah Co.: Moscow , 2560 ft, 2-IV-1932, T.A. Brindley [1 WFBM] ; same locality, 8-IV-1936, R.E. Miller [1 USNM] ; same locality, 17-V-1955, F.T. Cook [1 WFBM] ; same locality, 17-XII-1960, W.F. Barr [1 CMNC, 1 WFBM] ; same locality, 17-XII-1960, Phyllis Strecker, R.E. Strecker [2 CNCI, 1 WFBM] ; same locality, 10-V-1996, R. Sprague [1 WFBM] .

OREGON: [1 USNM A. caseyi type] ; Baker Co.: Lookout Mountain , 44°32.399′N, 117°16.845′W, 5218 ft, 30-IX-2014 to 22-II-2015, R.H. McPeak [1 FSCA] ; Umatilla Co.: Battle Mountain Summit , Hwy. 395, 45°16.225′N, 118°58.643′W, 4270 ft, 1-X-2014 to 21-II-2015, R.H. McPeak [1 FSCA] ; same locality, 9-XI- 2015, P. Skelley, K. Schnepp, R.H. McPeak, K. Arguez [1 DCGC, 4 FSCA, 1 KESC, 1 NHML] ; Exit 228 on I-84, Deadman Pass Rest Area, 45°35′54″N, 118°30′17″W, 3600 ft, 21-XI-2014, P. Skelley, K. Schnepp [2 FSCA] ; Fly Creek Valley , SE Umatilla Co., 15-XI-1961, Joe Schuh [1 FSCA] ; Toll Gate Rd. , Blue Mts, 7-VI-1938 [1 CASC] ; W of Tollgate ; MP 16/17 on Hwy 204, 45°47.466′N, 118°07.793′W, 4631 ft, 22-VIII-2014 to 1-III-2015, R.H. McPeak [1 FSCA] ; Union Co.: Johnson Rock USFWS Lookout, 15 mi. W, 14 mi. S La Grande, 5700 ft, 11-VII-1977, A.K. Johnson [1 EMEC] ; Off Spring Creek Rd. near Hwy 84, 45°22.207′N, 118°18.015′W, 3498 ft, 8-X-2013 to 21-VI-2014, R. H. McPeak [3 RMPC] ; Wallowa-Whitman Nat. For. off Spring Creek Rd. [NW. LaGrande], 45°22.207′N, 118°18.015′W, 3498 ft, 30-IX-2014 to 13-XI-2014, R.H. McPeak [2 FSCA] ; same locality, 30-IX-2014 to 21-II-2015, R.H. McPeak [1 FSCA] ; Wallowa Co.: 22 km. W. Troy, Long Meadows , 1230 m, 15-VIII-1955, J.F. O’Brien [1 UCDC] ; Enterprise area ; along Ant Flat Rd. , 45°31.071′N, 117°15.540′W, 4127 ft, 23-VIII-2014 to 13-IV-2015, R.H. McPeak [1 FSCA, 1 RMPC] ; Enterprise , north of, on Hwy 3, 45°40.054′N, 117°16.527′W, 4825 ft, 23-VIII-2014 to 13-IV-2015, R.H. McPeak [1 FSCA, 2 RMPC] .

WASHINGTON: Columbia Co.: Blue Mts., Godman Springs , 6000 ft, 7-VII-1929, M.C. Lane [1 USNM A. lanei type] ; Spokane Co.: Spangle , area, Jct. Jennings Rd & Parker Rd., 47°26′03.70″N, 117°26′ 07.19″W, 2377 ft, 24-VIII-2014 to 27-III-2015, R.H. McPeak [1 FSCA] ; Walla Walla Co.: 15-X-1946, F. Terukina [1 WSU] ; College Place , 14-XI- [?], Curtis Perkins [1 WSU] ; same locality, 14-X-1946, Barnell Bundy [1 FSCA] ; same locality, 8-XI-1946, G.H. Nelson [1 USNM] ; same locality, 30-IX-1947, N. Britton [1 USNM] ; same locality, 22-X-1947, C.A. Riggins [1 USNM] ; same locality, 1-XI-1947, LaJean Akins [1 FSCA] ; same locality, 1-XI-1947, H. Bennett [1 USNM] ; same locality, 6-XI-1947, Earle Lanthrop [1 WBWC] ; same locality, 12-V-1948, W. Masterjohn [1 USNM] ; Walla Walla , X-1946, J. Grozensky [1 USNM] ; Whitman Co.: Pullman , 28-XI-1898, C.V. Piper [1 USNM A. pullmani type] ; same locality, 15-IV-1930, N.M. Downie [1 FMNH] ; same locality, 3-IV-1931, N.M. Downie [3 FMNH] ; same locality, 3-IV-1961, N.M. Downie [2 CMNC] ; same locality, 27-X-1962, R.W. Dawson [1 FSCA] ; same locality, 20-XI-1962, R.W. Dawson [1 FSCA] ; same locality, 10-XII-1962, R.W. Dawson [1 FSCA] ; same locality, 16-XII-1970 [1 FSCA] ; 12.8 mi. SW Pullman, Lyle Grove Biol. Area , 28-29-IV-1995, C.N. Looney [1 WFBM] ; Rose Creek , 4 mi. N. Albion, 26-IV-1997, R. Rood [1 RMPC] .

Observed habits. Specimens have been collected in barrier pitfall traps, walking on snow, under log, and feeding on deer dung and carrion.

Remarks. Stenotothorax lanei is the largest member of the genus, and can occur along with S. niviviator n. sp., S. washtucna (Robinson) , and S. micellus Gordon and Skelley ; some of which have been misidentified in the past. However, S. lanei is distinguished by the thickened lateral pronotal bead, S. niviviator by the dull surface, S. washtucna by the reduced basal pronotal bead, and S. micellus by its smaller size and lack of the secondary protibial setal row.

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.