Onthophagus pexatus Harold, 1869

Reid, Chris A. M. & Runagall-Mcnaull, Aidan, 2022, A Revision of the Onthophagus pexatus Species-group, with Description of a New Brachypterous Species (Coleoptera: Scarabaeidae: Scarabaeinae), Records of the Australian Museum (Rec. Aust. Mus.) 74 (5), pp. 131-150 : 142-146

publication ID	https://doi.org/ 10.3853/j.2201-4349.74.2022.1821
publication LSID	lsid:zoobank.org:pub:364EB32F-A79D-41E4-BFCF-F28142C2D51B
persistent identifier	https://treatment.plazi.org/id/424B87F8-EC51-5062-FC9C-B0B5FDA9FD8B
treatment provided by	Felipe
scientific name	Onthophagus pexatus Harold, 1869
status

Treatment

Onthophagus pexatus Harold, 1869 View in CoL

Figs 7–8 View Figures 5–8 , 12 View Figures 11, 12 , 21–22 View Figures 21–24 , 28 View Figures 25–29 , 33 View Figures 30–34 , 40 View Figures 37–41 , 46–50 View Figures 42–48 View Figures 49, 50

Onthophagus pexatus Harold, 1869: 86 View in CoL ; Blackburn, 1903: 269; Lea, 1923: 355; Boucomont & Gillet, 1927: 214; Matthews, 1972: 209; Cassis & Weir, 1992: 146; Monteith & Kenyon, 2011: 57; Reid et al., 2022.

Material examined (60♂, 55♀). Australian Capital Territory: 1♀ / Tidbinbilla 26.viii.1976 D McAlpine ( AMS) ; New South Wales: 2♀ / Bogolong [?, label handwritten] ( AMS) ; 1♀ / 3k NW Carrowbrook on Mt Royal Rd ‘ Callicoma Hill’ private land [32.271°S 151.288°E 485 m] open grassy field 5–15.i.2013 JR Gollan, MB Ashcroft, K Turner HVARCLP/ A191/1/T1/bait (dung baited pitfall trap) ( AMS) GoogleMaps ; 19♂, 1♂ *, 8♀ / Cathedral Rock NP 30.4422°S 152.2797°E 1349 m site 60 c2k from park entrance, burnt dry scler forest, macropod dung baited pitfall 22–23.ii.2021 Reid & Runagall-McNaull ( AMS) GoogleMaps ; 2♂, 4♀ / Cathedral Rock NP 30.4416°S 152.2790°E 1347 m site 61 c2k from park entrance, burnt dry scler/open heath,macropod dung baited pitfall 22–23.ii.2021 Reid &Runagall-McNaull ( AMS) GoogleMaps ; 1♂ / Culoul Range, nr Putty , pollinating Typhonium brownii? Ii.1967 AN Dodd (AMS) ; 1♀ / Goulburn ( AMS) ; 1♂ / Hartley Vale, Blue Mtns , open forest at wombat dung, 11.x.2002, B Day & D McAlpine ( AMS) ; 1♀ / Jenolan SF 20.iv.1973 DA Doolan ( AMS) ; 2♀ / Lake Eucumbene , lake surface, 8.ix.1972 R Farragher ( AMS) ; 1♂, 1♂ *, 1♀ / ‘ Dairy Park’ 7.2 km SE Mandurama 33.70083°S 149.13412°E pitfall trap DAPA-LH-2 8–22.xii.2011 G Kay & D Florance ( AMS) GoogleMaps ; 1♀ / ‘ Mandurama’ 7.2 km SE Mandurama 33.70318°S 149.13646°E pitfall trap JROW-LH1-3 8–22. xii.2011 G Kay & D Florance ( AMS) GoogleMaps ; 2♀ / ‘ Red Hill’ 11.5 km SE Molong 33.16933°S 148.97742°E pitfall trap JTUX-GE-4 8–22.xii.2011 G Kay & D Florance ( AMS) GoogleMaps ; 1♀ / Mt Coricudgy 29.ix.1983 G Hangay ( AMS) ; 1♂ */ Mt Hyland NR 30.1757°S 152.4153°E 1265 m site 55 summit track, burnt closed dry scler forest, macropod dung baited pitfall 20–21.ii.2021 Reid & Runagall-McNaull ( AMS) GoogleMaps ; 2♂ / Mt Hyland NR 30.1753°S 152.4125°E 1254 m site 56 base of summit track, burnt grassy clearing in dry scler forest, macropod dung baited pitfall 21–22.ii.2021 Reid & Runagall-McNaull ( AMS) GoogleMaps ; 1♀ / Mt Hyland NR 30.1748°S 152.4119°E 1252 m site 57 base of summit track, burnt grassy clearing in dry scler forest, macropod dung baited pitfall 21–22.ii.2021 Reid & Runagall-McNaull ( AMS) GoogleMaps ; 1♂, 4♀ / Nullo Mtn SF, c8k SE Cox’s Ck [32.763°S 150.196°E 785 m], undisturbed rainforest gully, 6–16.i.2013 JR Gollan, MB Ashcroft,K Turner HVARCLP/A050/1–3/ T1/bait (dung baited pitfall trap) ( AMS) GoogleMaps ; 12♂, 1♂ *, 4♀ / Penrose SF 22.iv.1972 DADoolan ( AMS) ; 1♂, ditto except 6.v.1972 ( AMS) ; 1♂ / Putty SF 4–14.i.2013 JR Gollan, MB Ashcroft, K Turner HVARCLP/A008/2/T1/ bait (dung baited pitfall trap) ( AMS) ; 1♀ / Putty SF 4–14.i.2013 JR Gollan, MB Ashcroft, K Turner HVARCLP/A007/2/T1/bait (dung baited pitfall trap) ( AMS) ; 1♂ / Tallong 26.ii.1971 RH Mulder ( AMS) ; 1♂, 1♀ / Tamworth, private prop. W side of top of Bald Hill behind radio tower 31°04'33"S 150°57'24"E 15.xi – 6.xii.2001 H Doherty & M Elliott NDNW1/060/04 (pit trap) ( AMS) GoogleMaps ; 1♀ / Tweed River ( AMS) ; 1♂, 1♀ / [c2.5k E Wanganui 33.022°S 149.956°E 1050 m] open grassy field grazed by livestock 2k SE end of Vulcan Rd ‘ Cubby House’ private land, 6–16.i.2013 JR Gollan, MB Ashcroft, K Turner HVARCLP/A057/1/T1/bait (dung baited pitfall trap) ( AMS) GoogleMaps ; 3♀ / Warrumbungle Mtns 22.xi.1972 DA Doolan ( AMS) ; 1♂, 3♀ / Warrumbungle Mtns 3.x.1979 DA Doolan ; 2♂, 1♂ *, 4♀ / Wollemi NP, scattered trees 700 m from Thompson’s Rd , 2k N of Milbrodale, 5–15.i.2013 JR Gollan, MB Ashcroft, K Turner HVARCLP/A263/1-3/T1/bait (dung baited pitfall trap) ( AMS) ; 1♂ */ Wombeyan Caves 9.v.2001 BJ & CJ Day in wombat dung ( AMS) ; 1♂ */ [Woolomin] crown res. 0.9k along rd to Woolomin rubbish tip, 100 m E of rd, 31°18'05"S 151°9'20"E, 24.xi–15. xii.2001 L Wilkie, H Doherty, H Smith & M Elliott NDNW1/057/C2 (pittrap) ( AMS) GoogleMaps ; 1♀ / ‘ Talong’ 9 km S Wyangala - 34.05366°S 148.93733°E pitfall trap SLAV-S-2 8–22.xii.2011 G Kay & D Florance ( AMS) GoogleMaps ; Victoria: 2♀ / Melbourne ( AMS) ; 1♂ */ Tallangatta Valley site 41 15.iv.2009 per Belinda Pearce ( AMS) ; 1♂, 1♀ / Yallook Vale ( AMS) .

Additional records (not included in Matthews, 1972). Australian Capital Territory: 1/ 6k W Hall ( ANIC); 4k N Pialligo ( ANIC); 1/ Shepherd’s Lookout ( ANIC); New South Wales: 1/ 13k N Bombala ( ANIC); 1/ Canyon Leigh ( ANIC); 15/ W end Coolah Tops ( QMB); 3/ 7K WNW Hoskinstown ( ANIC); 1/ 2k NNW Jerangle ( ANIC); 1/ 17k N Molong ( ANIC); 1/ 4k NE Mt Wog Wog ( ANIC); 1/ Tuglo HS ( ANIC); 7/ Wyangala Dam ( QMB); Queensland: 16/ 5k & 9 km NE Allies Creek ( QMB); 1/ Bald Mtn ( QDAF); 4/ Isla Gorge NP ( QMB); 3/Moolayember Creek NP ( QMB); 3/ 8.5k SW Mt Hutton ( QMB); 2/ Mt Norman ( QDAF); 7/ Oak Wells HS ( QMB); 22/ Wonga Hills HS ( QMB); Victoria: 1/ 36K W Bairnsdale ( ANIC).

Redescription. Mature specimens dorsally dull grey-black, with or without reddish spot at base of 6th elytral interval, antennae reddish-brown, with dark grey to black clubs; teneral specimens with sides and apex of elytra reddish; densely microreticulate, with shiny less microsculptured anterior third of clypeus and legs, usually also shiny striae. Length, male 4.5–6 mm; female 4–7 mm.

Male. Head ( Fig. 21 View Figures 21–24 ). Surface dull and densely microreticulate, except shiny apical third of clypeus and margins, sparsely and finely punctured, covered with slightly curved long setae (abraded in most specimens). Clypeus not produced, margins narrowly reflexed, apex shallowly excavate with sides of excavation rounded, side margins slightly rounded; clypeal suture entirely effaced at frontal portion, genal portions present and raised; frons medially depressed, with or without feebly developed dull transverse ridges; eyes narrow, 5–6 facet rows in width, separated by 14–17 eye widths, canthus complete, closed by dorsal width of eye; apex of mentum shallowly excavate.

Thorax ( Figs 7–8 View Figures 5–8 , 12 View Figures 11, 12 , 28 View Figures 25–29 , 33 View Figures 30–34 ). Pronotum. Moderately convex, slightly narrower than elytra, without anteromedian swelling, disc usually evenly convex, but may be feebly depressed along midline in posterior third; surface smooth, entirely strongly and densely microreticulate, with scattered moderately large shallow punctures separated by 1–3× diameters, each with short semi-recumbent seta; anterior angles 80–90°; anterior margined, sides evenly margined without small setose punctures, base with or without raised edge; pronotal hypomeron dull and densely microsculptured throughout, finely punctured on outer half, punctures sparse with long erect setae. Elytra. Semi-ovate in dorsal view, with prominent humeri and preapical swelling, longer than pronotum along midline; dull and densely microreticulate, except striae and apical third of suture usually shinier; intervals flat, except a few specimens with minute shiny tubercles on anterior half of inner intervals; intervals with scattered small punctures and semi-recumbent setae, forming one to two loosely defined rows when viewed longitudinally, setae of outermost interval longer, scattered, their punctures larger; strial punctures faint, slightly broader than striae; epipleura with single row of curved setae. Metaventrite entirely shallowly microreticulate but medially shinier, shallowly convex with scattered long setae, but midline grooved; wing fully developed, folded twice in repose. Legs. Protibiae slightly elongated and narrowed but with large triangular lateral teeth, inner apical angle with dense but broad tuft of yellow setae about twice length of apical spur; distal face of apical tooth with loose sparse tuft of yellow setae about as long as apical spur, 4th (smallest) lateral tooth in basal half; metafemoral ventral surface smooth and mostly shiny, weakly microreticulate, with scattered large and small punctures, separated by 2–6 diameters.

Abdomen ( Fig. 40 View Figures 37–41 ). Ventrites dull, densely microreticulate, obscuring puncturation, each with single transverse row of erect pale setae; pygidium convex, densely and evenly microreticulate except shiny raised margins, punctures distinct or obscured by microreticulation, sparse, separated by>5 diameters, setae semi-recumbent, long and thin, length>10× width.

Aedeagus ( Figs 46–50 View Figures 42–48 View Figures 49, 50 ). In lateral view, parameres elongated but strongly deflexed, each with flat oval tip.

Female. Head ( Fig. 22 View Figures 21–24 ). Similar to male except transverse clypeal sutural ridge present, elevated in middle, reaching genal sutures or effaced before them; clypeus and anterior half of genae shiny, frons dull, frons usually slightly more strongly and closely punctured; pronotum often slightly narrower relative to elytra; protibiae short and straight, with large lateral teeth as male.

Notes. Matthews’ redescription was based on 375 males and females, including the female lectotype (Cassis & Weir, 1992), noting that the species was widespread from Adelaide (type locality) to Melbourne and from there to the Queensland border. More recent collecting, noted above, extends the distribution well into Queensland, but the tropical Australian records in the Atlas of Living Australia represent mislabelled or erroneously databased old material. Our material conforms to Matthews’ description except that the eyes are slightly more variable in size, the head is covered in setae in freshly emerged specimens, setal punctures on the elytra may have raised shiny rims and the 6th elytral interval often has doubled setae on its basal half .

The parameres of this species show some variation in size and shape of the apices, from large and robust, with broad apical flanges ( Figs 46 View Figures 42–48 , 49 View Figures 49, 50 ) to small and delicate with weakly developed flanges ( Figs 47–48 View Figures 42–48 , 50 View Figures 49, 50 ). One specimen of the second type is small (4.8 mm long) and worn and its head is more strongly punctured than any other males, but the feeble head ridges and all other characteristics of O. pexatus are present. For now we consider it a minor male. Specimens with the larger paramere apices also show some variation in their shape, also without obvious relationship to external variation, so our conclusion is that this is simply a variable species.

Many sites recorded here are in open grassland, woodland, or clearings in dry sclerophyll forest, habitat regarded as typical of this species ( Matthews, 1972). Some occurrences in closed forest may be due to recent fires at the sites, opening up their canopies (Reid et al., 2022). However, it also occurs in closed forest, for example in a rainforest gully, Nullo Mountain. Onthophagus pexatus is also known to be attracted to inflorescences of the lily Typhonium , a rainforest plant which is pollinated by Coleoptera and Diptera, by mimicking the scent of dung (Sayers et al., 2020).