Epironastes nigrisetosus Carne 1957
Creators: name: Hutchinson, Paul M.
name: Allsopp, Peter G.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Dynastidae
Epironastes
Epironastes nigrisetosus

description: Epironastes nigrisetosus Carne, 1957
(Figs. 41–56)
Epironastes nigrisetosus Carne, 1957: 126. (Fig. 322 ♂ head and pronotum; Fig. 323 ♂ mentum and maxilla; Fig. 326, ♀ head and pronotum; Figs. 328, 331 ♂ genitalia; Map 17); Endrődi 1974: 38, 65 (Fig. 48 ♂ parameres); Endrődi 1985: 382 (Fig. 1395 ♂ parameres); Cassis & Weir 1992: 401; Dechambre 2005: 68, map.
Epironastes nigrosetosus: Dechambre 2005: 67; Weir et al. 2019: 524 (misspellings).
Type series. Holotype ♂ (by original designation): W.A. Mus. A. Douglas // 48-2721 Tarin Rock [33.1073°S, 118.2332°E] // Holotype ♂ Epironastes nigrisetosus mihi P.B. Carne det. 1952 // Western Australian Museum Entomology Reg. No. E88704 // Type // genitalia and mouthparts on cards [in WAM, examined] (Figs. 41–42).
The type locality was given by Koch (1980) as “ Tarin Rock to Lake Grace, W.A., 33°07’S, 118°14’E to 33°06’S, 118°28’E ” and in the WAM specimen register entry for 48-2721 [2721st specimen entered for 1948] as “A.M.D[ouglas] Tarin Rock to Lake Grace”. The latter is 23 km east of Tarin Rock.
Other specimens examined. AUSTRALIA. WESTERN AUSTRALIA: 1♂, 1.12.78 // Gabbin [30.8331°S, 117.6467°E] M. Powell // Golding / Powell Collection donated 12.Feb.2002 [in WAM]; 2♂, ca. 4 km WNW Dempster Inlet (34°04’S, 119 ° 39’E) W. Aust. 1.Dec.1979 T.F. Houston 301-1 + A. Chapman // at flight afternoon [in WAM]; 1♂, Harrismith [32.9358°S, 117.8562°E] W. Aust. 20.11.1991 uv. light A. Szito // Agriculture (Dept) Western Australia 9972 // genitalia on card [in DAFWA]; 1♂, 20 km NNW Toodyay [31.4216°S, 116.3631°E] W.A. 10. Dec. 92. G. Harold // Golding / Powell Collection donated 12.Feb.2002 [in WAM]; 1♂, 18 km NNW of Toodyay [31.4216°S, 116.3631°E] W.A. G. Harold 15. Dec. 92 // Golding / Powell Collection donated 12.Feb.2002 [in WAM]; 1♂, Kukerin [33.1919°S, 118.0818°E] Western Australia 17.1.1994 uv light trap A. Szito // Agriculture (Dept) Wesern Australia 38084 [in DAFWA]; 1♂, W.A. Fitzgerald River National Park, Thumb Peak site TP4, 34°02’07.0S, 119°44’03.5E (GPS) 23.Sept.2011 J. Newell, A. Danks, under rocks [in WAM]; 2♂, Dryandra S.F. [32.7867°S, 116.8906°E] West. Aust. 3.Dec.2016 P. Hutchinson | Epironastes nigrisetosus ♂ Nyingarn Rd white sand mv light // PMH Coll # Dyn 1849, 1850 // genitalia on card [in PMH]; 8♂, Dryandra S.F. West Aust. 11.Nov.2017 P. Hutchinson | Epironastes nigrisetosus ♂ 1900-2100hrs to light // PMH Coll # Dyn 1980, 1993 genitalia on card, 1981, 1982, 1984 [in PMH], 1985 [in QM], 1983, 1988 [in WAM]; 2♂, Dryandra S.F. West. Aust. 9.Nov.2018 P. Hutchinson | Epironastes nigrisetosus ♂ to mv light // PMH Coll # Dyn 2077, 2078 [in PMH]; 2♂, Dryandra S.F. W. Aust. 9.November 2018 P. Hutchinson 12553, 12554 [in MHC]; 1♂, Dryandra S.F. West. Aust. 1.Dec.2018 P. Hutchinson | Epironastes nigrisetosus ♂ to mv light // PMH Coll # Dyn 2079 [in PMH]; 2♂, Dryandra S.F. West. Aust. 16.Nov.2019 P. Hutchinson | Epironastes nigrisetosus ♂ to mv light // PMH Coll # Dyn 2125, 2126 [in PMH]; 1♂, Dryandra S.F. West. Aust. 3.Dec.2019 P. Kay | Epironastes nigrisetosus ♂ to u. v. light // PMH Coll # Dyn 2124 [in PMH]; 1♂, Dryandra S.F. West. Aust. 15.Dec.2019 P. Hutchinson | Epironastes nigrisetosus ♂ to mv light // PMH Coll # Dyn 2104 [in PMH].
Redescription. Male holotype. Body (Figs. 43–44) black with antennal club with outer face bitexturous with dorsal portion black and ventral sixth chestnut brown, 19.3 mm long, 11.2 mm wide. Mentum strongly arcuate through 90°, surface flat, weakly reflexed at apex; ligula weakly bilobed. Antennal club (Figs. 43–47) only slightly longer than shaft, inner face setose, shallowly foveate on apical third. Clypeus (Figs. 43, 45–47) anteriorly punctate becoming coarsely and confluently punctate at base, longitudinally concave, divided by low longitudinal ridge, abruptly declivous from ridge joining antennal angles; clypeofrontal suture faint, obliterated medially. Frons (Figs. 43, 46–47) very coarsely and confluently punctate; ocular canthi with stout black setae along anterior margin. Pronotum (Figs. 43, 45–47) with anterior lateral angles slightly obtuse, widest in anterior half at one-third distance from anterior margin, anteromedian horn stout, erect, preceding a transverse impression confined to anterior half, basal convexity strongly developed, surface sparsely and finely punctate, punctures becoming coarser, denser and confluent towards margins and transversely elongate in impression. Scutellum (Fig. 43) sparsely micropunctate, becoming denser at basolateral margins. Each elytron (Figs. 43, 45) with sutural striae punctate, at least in anterior two-thirds, linear-punctate apically, elytral disc with broad, shallow, weakly umbilicate punctures not forming well-defined striae, intervals with random punctures, punctation becoming obsolete dorsally before apical calli, lateral declivity sparsely rugulose. Pygidium (Figs. 45, 48) moderately convex, weakly microreticulate, concentrically punctate, with long setae across base and restricted apical impunctate zone, apical ridge abruptly narrowed in middle. Abdominal sternites 2–4 (Fig. 44) setose across middle on posterior margins, last sternite with sparse border of long, dark brown setae; coxae (Fig. 44) bearing dark brownish-black vestiture. Metatibiae with basal carinae bearing long, acute setae, distal carinae bearing long, fine widely set ciliae on outer surface; metatibial spurs (Figs. 44, 48) of unequal length, broad, subspatulate and very straight. Genitalia as in Figs. 49–50.
Male variation. Body 15.6–21.7 mm long, 9.0– 12.6 mm wide; mentum weakly arcuate through 30° often with medial impression. Clypeal medio-longitudinal ridge absent. Pronotal tubercle large and more acute or small and obtuse (Figs. 46, 51-53), impression deeper with well-defined posterior margin, or shallower and posterior margin gradually sloping. Elytral punctation either more impressed (Fig. 43) or less impressed (Fig. 53). Pygidium with apical zone punctate.
Specimens from the northwest of its range (Gabbin, Toodyay, and Dryandra, Figs. 51, 53) are larger, with the tubercle more developed and acute, the pronotal impression deeper with posterior margin well defined, and the elytral punctation finer than specimens from the southern coast (Dempster Inlet and Thumb Peak, Figs. 43–46). However, both these forms are not specifically different to the holotype (Tarin Rock) and other specimens from near the type locality (Harrismith, Kukerin) that are intermediate to the northwest and south coast specimens (Fig. 52). The genitalia are similar across all populations, indicating that the species exhibits a range of forms through its known range from robust through to smaller in a northwest to south-east orientation (Fig. 56).
Female. Unknown.
Diagnosis. Epironastes nigrisetosus can be recognised by having the following combination of characters: body 15.7–21.7 mm; dark brown-black vestiture; mentum weakly 30° or strongly arcuate through 90° to apex with ligula apex weakly bilobed; antennal club with outer face with ventral portion only one-sixth the width; clypeus with apex widely truncate and reflexed, abruptly declivous from distinctly raised and rounded ridge joining antennal angles; pronotal horn stout erect, impression deep; elytral punctation obsolete anterior to apical calli. Epironastes nigrisetosus can be easily distinguished from E. abruptus, E. limbatus, and E, demarzi by its dark brown-black vestiture and larger size.
Habitat and behaviour. In the northern parts of its range (Fig. 56), this species appears to be associated with Eucalyptus wandoo with a dense understorey of Protaceae, and to a lesser extent of Casuarinaceae, Fabaceae, etc. on white sands (Figs. 54–55) within the Western Australian Wheatbelt (350–450 mm average annual rainfall). At Dryandra State Forest, males were collected at light only on or within 300 m of white sand; light trapping on harder redder soils yielded no specimens. Near the south coast at its southern range limit specimens of the minor form were captured in coastal Banksia heath over rock (T.F. Houston, personal communication); this area has an annual rainfall of about 600 mm.
Adult males have been captured at flight in the afternoon and at light mostly during the 2 hours following dusk. Specimens were collected only during visits from 9 November to 15 December; later visits to April resulted in no specimens being collected. The maximum temperature on 9 November 2018 was 33 °C, the first day> 30 °C for spring. On 16 November 2019, the maximum temperature was 40 °C at the end of a week where maximum temperatures were 38–40 °C and the ground was dry without any signs of rain on local tracks; six males were attracted to lights. On 15 December 2019, the fourth consecutive day with maxima> 40 °C, there were no signs of recent rain and three males were attracted to light. These observations indicate that E. nigrisetosus does not require rainfall to trigger emergence, but rather relies on temperature as an indicator. This is in contrast to several other Epironastes and other pseudoryctines that occur in the semi-arid zone and that emerge immediately after summer rainfall.
No females were seen at lights, consistent with Carne’s (1957) thoughts that females of the Pseudoryctina are mostly sedentary. A search for females and signs of larva within the area on 1 December 2018 at the base of Eucalyptus trees and under fallen logs found only infrequent small amounts of large larval faecal pellets, but as no larvae, adults or adult remains were found with them, their identity is unknown. Other dynastines collected at the site were Semanopterus calabyi Carne, 1957, S. angustatus Blackburn, 1888, S. leai (Blackburn, 1897), Cryptodus bilobus Lea, 1917, C. foveatus Lea, 1919, Novapus simplex Sharp, 1875, and the introduced Heteronychus arator (Fabricius, 1775).
description: Published as part of 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, pp. 428-448 in Zootaxa 4852 (4) on pages 442-447, DOI: 10.11646/zootaxa.4852.4.2, http://zenodo.org/record/4410041