Epironastes limbatus Carne, 1957

Hutchinson, Paul M. & Allsopp, Peter G., 2020, Revision of Epironastes Carne, 1957 (Coleoptera: Scarabaeidae: Dynastinae Pentodontini: Pseudoryctina) with description of the female, behaviours, and habitats, Zootaxa 4852 (4), pp. 428-448 : 438-442

Epironastes limbatus Carne, 1957

( Figs. 30–40 , 56 )

Epironastes limbatus Carne, 1957: 126 (Fig. 324 ♂ maxilla and mentum; Fig. 325 ♂ head; Fig. 330 ♂ parameres; Fig. 332 ♂ pygidium; Map 17); Endrődi 1974: 38, 65 ( Fig. 49 ♂ parameres); Endrődi 1985: 382 (Fig. 1396 ♂ parameres); Cassis & Weir 1992: 401; Dechambre 2005: 68 (Fig. ♂ adult; map; Plate 2 Fig. 83 ♂ adult); Weir et al. 2019 (Plate 54O ♂ adult).

Type series. Holotype ♂ (by original designation): Type // Marloo Stn. [28.3218°S, 116.1740°E] Wurarga W.A. 1931-1941 A. Goerling // Holotype ♂ Epironastes limbatus mihi P.B. Carne det. 1952 // Holotype // ANIC image // genitalia on card [in ANIC, examined] ( Figs. 30–31 ) .

Paratypes: 1♂, Cunderdin [31.6510°S, 117.2376°E] W.A. Feb.1914 425 // Isodon Curtus Burm. [ Trissodon curtus (Burmeister, 1847) ] Id by A.M. Lea // Paratype ♂ Epironastes limbatus mihi P.B. Carne det. 1952 // ♂ paratype // mouthparts on card [in WAM] ; 1♂, 37-814 Kukerin [33.1919°S, 118.0818°E] // W.A. Mus A. Douglas // Paratype // Paratype ♂ Epironastes limbatus mihi P.B. Carne det. 1952 // mouthparts on card [in WAM]. Carne (1957) listed two additional male paratypes in SAM from “ Australia ” and “Swan R.”, respectively; the latter was often used as a general descriptor for southwestern Western Australia .

Other specimens examined. AUSTRALIA. WESTERN AUSTRALIA: 1♂, Perenjori [29.4399°S, 116.2916°E] W. Aust. 21.iii.1972 K.T. Richards // Agriculture (Dept) Western Australia 9071 // genitalia on card [in DAFWA] ; 11♂, 36 km W. of Southern Cross [31.3325°S, 118.9689°E] W. Aust. 26.Jan.2016 P. Hutchinson | ♂ in storm puddle // PMH Coll # Dyn 1693, 1694, 1695, 1703 [genitalia on cards], 1701, 1702, 1697, 1698 [in PMH], 1696 [in QM], 1699, 1700 [in WAM] ; 7♂, 10 km W. of Yellowdine [31.2773°S, 119.5551°E] West. Aust. 26.Jan.2016 P. Hutchinson | ♂ in storm puddle // PMH Coll # Dyn 1704, 1708 [genitalia on cards], 1705, 1706, 1707, 1711, 1712 [in PMH] ; 2♂ 10 km W. of Yellowdine West. Aust. 26.Jan.2016 P. Hutchinson | ♂ in storm puddle // PMH Coll # Dyn 1709[10347], 1710[10348] [in MHC] .

Redescription. Male holotype. Body ( Figs. 32–33 ) black, sometimes with red tinge, dorsal half of antennal club reddish brown and ventral half dull fawn, 13.5 mm long, 7.5 mm wide. Mentum strongly and abruptly reflexed through 90°, surface flat, narrowed to ligula; ligula abruptly constricted before divergent and truncate apex. Antennal club ( Figs. 33–36 ) only slightly longer than shaft, inner face setose, shallowly foveate in apical half, outer face bitexturous. Clypeus ( Figs. 32, 35–36 ) gently declivous from low rounded ridge joining antennal angles, lateral ridges distinct, apex arcuate and reflexed, surface rugulose; clypeofrontal suture distinct. Frons ( Figs. 32, 35–36 ) rugulose; ocular canthi broad, anterior margin obtusely angulate, laterally subequal to margin of eye, surface coarsely punctate with anterior margin bearing setae. Pronotum ( Figs. 32, 34–36 ) with anterolateral angles forming right angles, widest slightly anterior to midlength, anteromedial tubercle small, preceding a shallow subcircular impression restricted to anterior half and with a shallower depression extending to basal margin, disc weakly convex and without distinct basal convexity, surface with distinct sparse fine punctures becoming larger and denser towards margins, tending transverse in impression. Scutellum ( Fig. 32 ) bearing large punctures over entire surface. Each elytron ( Figs. 32, 34 ) with sutural striae linear-punctate, sutural costa distinctly raised, elytral disc with broad, deeply impressed somewhat annulate punctures forming conspicuous striae, intervals with numerous random large punctures, micropunctures and surface microreticulate. Pygidium ( Fig. 37 ) moderately convex, concentrically punctate, weakly microreticulate, setose across base, apical ridge glabrous. Abdominal sternites 2–4 ( Fig. 33 ) laterally setose over entire surface and glabrous medially, sternite 5 laterally setose over entire surface and glabrous across middle, last sternite across entire posterior border with dense long setae. Coxae ( Fig. 33 ) bearing yellow vestiture; metatibia with basal carina bearing long, acute setae, distal carina with short, stout, closely set ciliae on outer surface; metatibial spurs ( Fig. 37 ) of unequal length, long, subparallel, both spurs slightly curved. Genitalia as in Figs. 38–39 .

Male variation. Body dorsally dark brown to black, ventral surfaces and legs light brown, tending dark brown at margins, 9.7–13.1 mm long, 6.0– 8.1 mm wide. Antennal club with inner face foveate in apical third and bitexurous. Clypeal apex not reflexed; clypeofrontal suture faint. Ocular canthi anterior margin strongly arcuate. Pronotal armature as low swelling, medial depression posterior to impression obsolete. Abdominal sternite 5 sparsely setose at midlength across middle. Metatibia with longer spur slightly curved.

Female. Unknown.

Diagnosis. Epironastes limbatus can be recognised by: small size, body 9.7–13.1 mm long, vestiture yellow; mentum abruptly reflexed to ligula with ligula constricted prior to divergent and truncate apex; ocular canthi with anterior margin angulate or strongly arcuate; pronotum with a small tubercle and shallow subcircular impression; sutural costa on elytra distinctly raised; pygidium setose across base and last sternite with continuous dense, long fringe setae along posterior margin. It differs from E. nigrisetosus by its much smaller size and yellow vestiture, from E. abruptus by having the clypeus gently declivous anterior to antennal angles and the pygidium being setose across base, and from E. demarzi by having a shallow, subcircular, weakly-defined pronotal impression and a glabrous pygidial ridge.

Habitat and behaviour. This species occurs within the Western Australian Wheatbelt in mallee areas with a Melaleuca -dominant understorey on yellow sandplains ( Fig. 40 ) and with an average annual rainfall of 280–360 mm ( Fig. 56 ).

It is diurnally active with males flying around 14:00 hr and emergence is in response to summer rainfall (Janu-ary–March). On 26 January 2016, thunderstorms over the previous 1–2 days resulted in storm puddles through much of the range of E. limbatus . Live and dead males were collected from puddles near Southern Cross at about 14:00 hr, with further live specimens seen floating on later inspections that day, indicating diurnal flights. Later that day, culverts with storm water in them near Yellowdine yielded more males. Light-trapping there ( Fig. 40 ) from 19:30 (dusk) to 21:30 hr (moon rise) yielded no E. limbatus attracted to light, although adults of the dynastines Semanopterus angustatus Blackburn, 1888 and Carneoryctes psilus ( Carne, 1957) were attracted to the light.

Figures

FIGURE 40. Epironastes limbatus Carne, 1957 habitat at 10 km west of Yellowdine.

FIGURE 56. Known distribution of Epironastes species in southern Western Australia.

FIGURES 30–31. Epironastes limbatus Carne, 1957, holotype male. 30, dorsum; 31, labels.

FIGURES 32–39. Epironastes limbatus Carne, 1957, male specimen #1703; 32, dorsum; 33, venter; 34, lateral; 35, head, lateral; 36, head, dorsal; 37, pygidium; 38, parameres; 39, aedeagus, lateral.

FIGURES 43–50. Epironastes nigrisetosus Carne, 1957, male, Dempster Inlet specimen. 43, dorsum; 44, venter; 45, lateral; 46, head, lateral; 47, head, dorsal; 48, pygidium; 49, parameres; 50, aedeagus, lateral.