Cinacanthus cunninghami Warner, 2021

Warner, William B., 2021, Two new scarab beetles from the southwestern USA (Coleoptera: Scarabaeidae: Melolonthinae and Aphodiinae), Insecta Mundi 2021 (855), pp. 1-15 : 9-14

Cinacanthus cunninghami Warner , new species

Figures 20–28

Diagnosis. Elytral and clypeal discs lacking long setae; pronotum with posterolateral angles obsolete; protibia with ramus unusually narrow, teeth unusually long and narrow.

Type data. Holotype male (deposited at ASUT) and allotype female labeled: “ USA: AZ: Coconino Co., dune 1.5 mi. WSW of Moenkopi; 36°05′56″N, 111°12′03″, May 4, 2013, W.B.Warner & R. A.Cunningham ”.

Description of holotype male. Length: 5.5 mm; widest width (about apical 3⁄5 of elytron): 2.5 mm. Body ( Fig. 20 ) elongate-subpyriform, body and legs light reddish-brown, elytra testaceous, integument subtransparent, flight wings visible through elytra. Head ( Fig. 24 ) subtrapezoidal, with free margins weakly convex and fimbriate, genae prominent from eyes but continuous with lateral margins of clypeus which are weakly irregularly

serrate-crenulate, apex emarginated, at each side of emargination with distinct narrow tooth arising from beneath margin, tooth reflexed and extending anterodorsally; clypeofrontal suture bisinuate, front and upper clypeus finely, sparsely punctured similar to anteromedial area of pronotum, medially mostly impunctate, apical half of clypeus obscurely tuberculate-punctate, epistome between clypeal teeth with weak semicircular depression covering nearly half clypeal length; in dorsal view, eye small, about 1⁄7 of dorsal interocular width. Pronotum broad (length about 4⁄5 width), laterally explanate with fimbriate margin, widest slightly anterior to middle, posterior margin vaguely obtusely angulate, but very broadly rounded, marginal bead fine but distinct on lateral margins, obsolescent between humeri and obsolete on anterior margin, posterior angles nearly obsolete, anterior angles rounded, disc in middle third moderately punctate, punctures round, mostly separated by about 1–3 times their own diameters, punctures increasing in size and density laterally, posterolaterally pronotum slightly depressed and punctures becoming even larger, elongate-subocellate and often subconfluent in longitudinal series ( Fig. 26 ). Scutellum narrower than elytral sutural and second intervals taken together at elytral midpoint, slightly longer than wide, lateral margins convex to acutely angulate apex, disc very sparsely minutely punctate. Elytron about 2.3 times as long as pronotum, with 6 distinct, subequidistant striae between humerus and suture, striae finely punctate, punctures mostly separated by about 2–4 times their own diameters; intervals weakly convex, sparsely vaguely punctate, punctures irregular in size and placement, but mostly smaller than pronotal punctures; posterolaterally punctures setigerous, setae short, erect. Venter ( Fig. 21 ) with metasternite in middle third somewhat coarsely, sparsely punctate, setigerously punctate in lateral thirds, with broad shiny impunctate subtriangular area along posterior margin at each side, metasternal midline impressed; abdominal ventrites sparsely setigerously punctate. Legs delicate and narrow, protibia tridentate, teeth unusually long and narrow, basal tooth at about basal third of tibia, apical tooth evenly curving outward from middle tooth; spur obsolescent, minute and appressed to tibia, extending to about basal third of first protarsomere; meso- and metafemur with anteroventral sixth or so (i.e. area along posterior margin of normally “ventral” face in repose) in basal two thirds with setigerously and subcontiguously punctulate patch, this area declivous and flattened, setae in patch subdecumbent, golden ( Fig. 27 ); anterior femoral face at about ventral third with single line of darkened coarse setae in about distal 2/3; metatibia subequal in length to metatarsus. Genitalia ( Fig. 22–23 ) with parameres unadorned and subtriangular in lateral view, similar to those of other Cinacanthus species.

Female allotype. Length: 6.6 mm; widest width (slightly behind elytral midpoint): 2.5 mm. Very similar to male, differing primarily in secondary sexual characteristics: Clypeus with outer lateral margins less convex to nearly straight ( Fig. 25 ), protibial spur more prominent and visible, though tiny, extending to about middle of first protarsomere, protibia usually less bowed; metafemur in anteroventral fifth (i.e. near posterior edge of visible face in repose) simply punctate, with scattered hairs ( Fig. 28 ), not flattened and declivous.

Paratypes. 9 males, 5 females with data: Same as holotype (4m, 2F); same except “iv.4–5.2013” (1m) ; same except: “dunes at night, April 20, 2012, W.B. Warner, J.P.Gruber ” (1m, 2f); same except: “ April 24, 2014, on dunes-night & UV light, W.B. Warner ” (2m, 1f); same except: “ Hwy. 264, 2.1 rd. mi. SE Moenkopi ; 11 August 1992; R. A. Cunningham, collector; in sand dunes, MV & BL ” (1m) .

Specimens are deposited in the following collections: ASUT, CSCA, FSCA, RACC, UAIC, WBWC.

Variation. Males: Length 5.2–6.3 mm, widest width 2.4–2.9 mm. Females: Length 5.8–6.7 mm, widest width 2.6–2.9 mm. Other than variation in size, muting of setal length through wear, and vague color differences, the paratypes are remarkably uniform. Some females have one or both protibial spurs missing (lost; socket present); some males have a tiny, almost setiform protibial spur on one or both sides, spur being less than half size of female spur.

Etymology. I am pleased to name this species after Richard A. Cunningham of Show Low, Arizona, good friend and master scarab collector who captured the first known specimen of this species.

Habits and Habitat. The type series was collected on small dunes south of Moenkopi Creek; however, the dunes are not riparian, instead consisting of “spill-over” into the canyon from larger wind-blown dunes on the mesa above where this species probably also occurs. Primary perennial plants bordering the mostly bare dune are Atriplex , Artemisia , and Ephedra species. I observed a few specimens flying very rapidly (for an aphodiine) approximately 15 cm above the surface of open sand of the consolidated dune at dusk. I knocked one specimen by hand onto a blacklight sheet as it flew by before dark, but it did not appear to be attracted to the light. Other specimens were collected at blacklights after dark, and some specimens were collected in black pitfall traps (empty, simulating rodent burrows) set shortly before dusk and picked up after dark. No specimens were seen on the hardpan surrounding the dune. Given this, its unusual gracile tibial form, light pigmentation and subtransparent elytra, C. cunninghami is apparently a true arenophile.

Based on known habits of other Cinacanthus species , this species is expected to be an inquiline of kangaroo rats ( Dipodomys species ) or other burrowing rodents whose burrows are common at the type locality. Other aphodiine species collected with C. cunninghami using the same methods were Cinacanthus near ulkei Gordon, Tetraclypeoides moquinus (Fall), and Dellacasiellus near milleri Gordon and Skelley.

Relationships. Cinacanthus cunninghami phenotypically appears to be intermediate between C. militaris (LeConte) , C. hirsutus (Brown) and C. coquillettii (Linell) : It has the pronotum laterally explanate and posterolateral pronotal punctures enlarged vaguely similar to those of C. coquillettii , but lacks the short clypeal hair of that species. Although vaguely similar in general facies, specimens of C. hirsutus are darker, more coarsely punctate, and have thicker protibiae, distinctly setose elytra, and pronotal margins that are usually obviously crenulate. The only other Cinacanthus species with adults that have gracile protibiae is C. militaris , though even in that species the tibiae are noticeably thicker than those of C. cunninghami . Additionally, specimens of C. militaris has a more quadrate pronotum with finer punctures.

Cinacanthus cunninghami keys as far as C. crenicollis (Fall) in Gordon and Skelley’s (2007) key to Cinacanthus ; but has a different pronotal shape. The applicable couplet may be modified to accept this species as follows:

4(3). Pronotal punctures comparatively small laterally in basal 3/4, 3–6 times as large as punctures on vertex; pronotum normally convex, posterior angles various..................................... 4a

— Pronotal punctures large laterally in basal 4⁄3, 8–10 times as large as punctures on vertex (Fig. 931–932); pronotum strongly convex, posterior angles obscure, oblique, broadly rounded; pronotum not quadrate............................................................................ 5

4a(4). Protibia with width of ramus between teeth narrow, equivalent to distinctly less than half distance between apices of clypeal teeth; pronotum subpentagonal, laterally explanate, basolateral margins oblique, with posterior angles broadly rounded, subobsolescent......................................................................................... C. cunninghami Warner , n. sp.

— Protibia with width of ramus between teeth moderately wide, equivalent to about half distance between apices of clypeal teeth; pronotum subquadrate, only weakly explanate laterally, with posterior angles more narrowly rounded and distinct.................................... C. crenicollis (Fall)

Figures

Figure 26. Cinacanthus cunninghami male, dorsolateral view of head and pronotum.

Figures 20–23. Cinacanthus cunninghami. 20) Male dorsal habitus. 21) Female ventral habitus. 22) Male genitalia, dorsal view of parameres. 23) Lateral view of parameres.

Figures 24–25. Cinacanthus cunninghami dorsal views of head. 24) Male. 25) Female.

Figures 27–28. Cinacanthus cunninghami ventral views of mesofemora. 27) Male (arrows indicating setal tufts). 28) Female, setal tufts lacking.