Epironastes abruptus 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 : 430-435

Epironastes abruptus Carne, 1957

( Figs. 1–18 , 56 )

Epironastes abruptus Carne, 1957: 127 (Figs. 327, 329 ♂ genitalia; Fig. 333 ♂ head; Map 17); Endrődi 1974: 38, 65 ( Fig. 50 ♂ parameres); Endrődi 1985: 382 (Fig. 1397 ♂ parameres); Cassis & Weir 1992: 400; Dechambre 2005: 68, map.

Type series. Holotype ♂ (by original designation): 43-565 Salmon Gums [32.9813°S, 121.6440°E] // Type // Holotype ♂ Epironastes abruptus mihi P.B. Carne det. 1952 // Western Australian Museum Entomology Reg. No. E88679 // genitalia on card [in WAM, examined] ( Figs. 1–2 ).

The type locality was given by Koch (1980) as “43-565, A.K. Brown; col. 8.vii.1943; Salmon Gums, W.A., 32°59’S, 121°39’E ” and in the WAM specimen register entry for 43-559 to 43-567 [559th to 567th specimens entered for 1943] states “Mrs A.K. Brown Salmon Gums, a fly (9)” [9 specimens donated including #565], but collector and date not given on labels ( Fig. 2 ).

Other specimens examined. AUSTRALIA. WESTERN AUSTRALIA: 1♂, 106 km E. of Lake King [32.7048°S, 120.6479°E] W.A. 3.Feb.1999 P. Hutchinson // PMH Coll # Dyn 0468 [in PMH] ; 1♂, Moir Rd, 8 km S. of Ravensthorpe W. Aust. [33.6463°S, 120.0407°E] 13.Feb.2011 P. Hutchinson | Epironastes abruptus ♂ in roadside puddle // PMH Coll # Dyn 0471 [in QM] ; 2♀, Moir Rd , 8 km S. of Ravensthorpe W. Aust. 16.Feb.2011 P. Hutchinson | ♀ crawling on track 0830-1100hrs // PMH Coll # Dyn 0466 [in WAM], 0468 [in PMH] ; 1♂, Moir Rd , 8 km S. of Ravensthorpe W. Aust. 16.Feb.2011 P. Hutchinson | ♂ flying 0815 hrs // PMH Coll # Dyn 0465 // genitalia on card [in PMH] ; 1♂, Moir Rd , 8 km S. of Ravensthorpe W. Aust. 16.Feb.2011 P. Hutchinson | ♂ crawling on track 0815-1100 hrs // PMH Coll # Dyn 0470 [in PMH] ; 1♀, Moir Rd, 8 km S. of Ravensthorpe West. Aust. 19.Feb.2008 P. Hutchinson | walking on sand beneath mallee heath // PMH Coll # Dyn 0464 [in PMH] .

Redescription. Male holotype. Body with dorsal surfaces ( Fig. 3 ) and abdominal sternites ( Fig. 4 ) black, sometimes with red tinge, ventral surfaces and legs brown, 15 mm long, 9.3 mm wide. Mentum strongly reflexed at apex; ligula narrow, truncate apex. Antennal club ( Fig. 6 ) slightly longer than shaft, inner face setose, shallowly foveate in apical third, outer face bitexturous with dorsal portion black and ventral quarter chestnut brown. Clypeus ( Figs. 3, 7 ) strongly curved downwards from antennal angles, very short, narrowed abruptly to short reflexed apex, surface transversely rugose; clypeofrontal suture obliterated. Frons ( Figs. 3, 6–7 ) concentrically rugose; ocular canthi with anterior margin arcuate and bearing stout orange-yellow setae. Pronotum ( Figs. 3, 5–6 ) with anterolateral angles forming right angles, widest in anterior half slightly before midlength, anteromedian horn stout, erect, preceding transverse impression confined to anterior half, continued over basal convexity by shallow depression, surface sparsely and finely punctate, punctures becoming coarser, denser and confluent towards margins and transversely elongate in anterior impression. Scutellum ( Fig. 3 ) bearing moderate punctures becoming finer towards apex. Each elytron ( Figs. 3, 5 ) with sutural striae linear-punctate, elytral disc with large simple punctures forming distinct striae, intervals impunctate with apical declivity rugulose. Pygidium ( Fig. 8 ) scarcely convex, shallowly and concentrically rugose, sides sparsely setose, almost glabrous across middle of base, without a smooth apical zone, apical ridge not narrowed in middle. Abdominal sternites 2–5 ( Fig. 4 ) sparsely setose at midlength laterally, glabrous across middle, last sternite with sparse posterior border of long orange-yellow setae. Coxae ( Fig. 4 ) bearing orange-yellow vestiture; metatibiae slender, basal carinae bearing long, acute setae; distal carinae bearing combination of long, fine, widely set ciliae and setae on outer surface; tibial spurs of metathoracic legs ( Fig. 4 ) unequal length, broad, subspatulate with longer spur slightly curved. Genitalia as in Figs. 9–10 .

Male variation. Body 12.9–18.3 mm long. Antennal club non foveate, dorsal portion of outer face dark brown. Clypeal surface coarsely punctate; clypeofrontal suture distinct, medially posteriorly arcuate.

Female. Differs from male in the following characters: body 16.4–17.5 mm long, 9.9–10.6 mm wide. Antennal club shorter than shaft, inner face convex and sparsely setose, outer face unitexturous. Clypeal apex ( Figs. 11, 14– 15 ) narrower. Pronotum ( Figs. 11, 13–16 ) with anterolateral angles slightly acute, anteromedial tubercle absent, impression as small flattened area with trace of impression over basal convexity but not distinctly interrupting pronotal convexity in lateral view. Scutellum ( Fig. 11 ) bearing moderate punctures near margins. Elytral surfaces ( Figs. 11, 13 ) bearing sparse punctures in intervals, apical calli obsolete with elytra evenly sloping to apex. Pygidium bearing short setae across base. Abdominal sternites 2–5 and last sternite ( Fig. 12 ) bearing long setae on entire surface and across middle. Protibial denticles ( Figs. 11–12 ) broader; metatibiae ( Fig. 12 ) longer and apex wider, distal carina bearing very small ciliae, longer spur straight; metatarsomeres ( Figs. 11–12 ) shorter than tibial length.

Diagnosis. Epironastes abruptus is recognised by having: body dorsally black with brown legs and ventral surface (except sternites), orange-yellow vestiture; 12.9–18.3 mm long; clypeus short to very narrowly reflexed apex; pronotal impression continued over basal convexity; pygidium glabrous across base (setose in females), surface without impunctate apical zone. It differs from E. nigrisetosus by having orange-yellow vestiture, from E. demarzi by the base of the pygidium and the apical ridge without setae, and from E. limbatus by the larger size, a deeper pronotal impression that continues over the basal convexity, and the pygidium being glabrous across the base.

Habitat and behaviour. Epironastes abruptus appears to be associated with mallee ( Eucalyptus species that grow to a height of 2–9 m and have many stems arising from a swollen woody base, the lignotuber) in sandy areas within the hinterland of the southern central coast mallee-heath area from Ravensthorpe to Salmon Gums that has a 350–430 mm average annual rainfall ( Figs. 17–18 , 56 ).

This species is diurnally active with males and females being recorded from about 08:30–11:00 hr, emerging in response to summer rainfall (January–March). On 3 February 1999, a male was captured in flight at the end of a road culvert at 10:15 hr in low mallee heathland east of Lake King. On 19 February 2008, near Ravensthorpe, a female was found walking on a track. The weather conditions were mostly overcast, cold, windy with some light rainfall, but the previous day was 35 °C with thunderclouds developing and very humid. On 13 February 2011, also near Ravensthorpe, a male was found alive in a roadside storm puddle; light trapping at dusk that day yielded no adults. On 16 February 2011 from 08:15–11:30 hr in the same area, the conditions were very overcast with a cool breeze. One male was collected actively flying at 08:30 hr, whilst three males and two females were collected walking on the ground alongside a track with several ant nests on a roadside grading pile adjacent to dense mallee heath ( Fig. 17 ) (a male and a female had ants attached). Several mallee stumps were dug from the white sandy-loam with gravel to about 15 cm over rocky clay (solid, as impenetrable with a pick-axe, Fig. 18 ) without signs of larval frass, larvae or adult remains.

Figures

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

FIGURES 1–2. Epironastes abruptus Carne, 1957, holotype male. 1, dorsum; 2, labels.

FIGURES 3–10. Epironastes abruptus Carne, 1957, male specimen #0465. 3, dorsum; 4, venter; 5, lateral; 6, head, lateral; 7, head, dorsal; 8, pygidium; 9, parameres; 10, aedeagus, lateral.

FIGURES 11–16. Epironastes abruptus Carne, 1957, female specimen #0464. 11, dorsum; 12, venter; 13, lateral; 14, head, lateral; 15, head, dorsal; 16, head and pronotum, frontal.

FIGURES 17-18. Epironastes abruptus Carne, 1957 habitat near Ravensthorpe. 17, landscape view; 18, soil pit with almostimpenetrable layer.

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.