A Revision of the Onthophagus pexatus Species-group, with Description of a New Brachypterous Species (Coleoptera: Scarabaeidae: Scarabaeinae)
Author
Reid, Chris A. M.
Author
Runagall-Mcnaull, Aidan
text
Records of the Australian Museum
2022
Rec. Aust. Mus.
2022-11-30
74
5
131
150
http://dx.doi.org/10.3853/j.2201-4349.74.2022.1821
journal article
10.3853/j.2201-4349.74.2022.1821
2201-4349
13228969
364EB32F-A79D-41E4-BFCF-F28142C2D51B
Onthophagus pexatus
Harold, 1869
Figs 7–8
,
12
,
21–22
,
28
,
33
,
40
,
46–50
Onthophagus pexatus
Harold, 1869: 86
; 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
)
;
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
)
;
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
)
;
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
)
;
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
)
;
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
)
;
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
)
;
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
)
;
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
)
;
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
)
;
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
)
;
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
)
;
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
)
;
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
)
;
Victoria
:
2♀
/
Melbourne
(
AMS
)
;
1♂
*/
Tallangatta Valley
site 41
15.iv.2009
per
Belinda Pearce
(
AMS
)
;
1♂
,
1♀
/
Yallook Vale
(
AMS
)
.
Figures 25–29
.
Onthophagus
species
, venter of right metafemur. (
25
)
O. bulga
sp. nov.
; (
26
)
O. longipes
Paulian
; (
27
)
O. nammuldi
Matthews
; (
28
)
O. pexatus
Harold
; (
29
)
O. squalidus
Lea.
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
).
Figures 30–34
.
Onthophagus
species
, left protibia. (
30
)
O. bulga
sp. nov.
; (
31
)
O. longipes
Paulian
; (
32
)
O. nammuldi
Matthews
; (
33
)
O. pexatus
Harold
; (
34
)
O. squalidus
Lea.
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
). 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
,
12
,
28
,
33
). 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
). 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.
Figures 35–36
.
Onthophagus bulga
sp. nov.
, wing and metaventrite.
Figures 37–41
.
Onthophagus
species
, pygidium. (
37
)
O. bulga
sp. nov.
; (
38
)
O. longipes
Paulian
; (
39
)
O. nammuldi
Matthews
; (
40
)
O. pexatus
Harold
; (
41
)
O. squalidus
Lea.
Figures 42–48
.
Onthophagus
species
, aedeagus, lateral. (
42
)
O. bulga
sp. nov.
; (
43
)
O. longipes
Paulian
; (
44
)
O. nammuldi
Matthews
; (
45
)
O. squalidus
Lea
; (
46
)
O. pexatus,
Dairy Park, NSW
; (
47
)
O. pexatus,
Wombeyan Caves, NSW
; (
48
)
O. pexatus,
Woolomin, NSW.
Aedeagus (
Figs 46–50
). In lateral view, parameres elongated but strongly deflexed, each with flat oval tip.
Female
. Head (
Fig. 22
). 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
,
49
) to small and delicate with weakly developed flanges (
Figs 47–48
,
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).