The dung beetle fauna of the Big Bend region of Texas (Coleoptera: Scarabaeidae: Scarabaeinae)
Author
Edmonds, W. D.
text
Insecta Mundi
2018
2018-07-27
642
1
30
journal article
10.5281/zenodo.3708186
f503e20e-e3fb-41ac-bf17-bdaf221bc7c7
1942-1354
3708186
55CCB217-771C-499D-9110-36F143C375C5
Onthophagus browni
Howden and Cartwright
Fig. 41–43
Diagnosis.
Dorsum black, occasionally showing weak greenish reflections; legs coffee brown. Length
5–7.5 mm
. Pronotum evenly but not densely covered by small shining granules, each with associated short seta, on field of extremely fine shagreening (as in
Fig. 48
); elytral interstriae with two longitudinal rows of small, setose granules on field of fine shagreening; pygidium evenly punctate, punctures setose. Front legs similar in the two sexes. Male (
Fig. 41–42
) – Head lacking horns, bearing two transverse carinae; clypeus slightly upturned medially. Pronotum with large, flattened, apically widened, emarginate process extending over posterior portion of head (reduced in small individuals). Female (
Fig. 43
) – Head bearing two simple, transverse carinae; clypeal margin not upturned. Pronotum convex except for low, transverse ridge rising above anterior margin. Complete formal description given by
Howden and Cartwright (1963)
.
Big Bend collection sites
(altitudinal range:
725–1785 m
).
Presidio Co.
:
[1]
C.E. Miller Ranch (~
16 km
W
Valentine),
30°32′50″N
104°39′40″W
(Camp Holland)
1410 m
(Aug)
;
[2]
~
16 km
W Valentine
(
Miller Ranch
, near headquarters),
30°33°30″N
104°38′44″W
,
1350 m
(
Jul–Aug
)
;
[3]
~
6 km
W Marfa
(Hip-O
Ranch
),
30°21′54″N
104° 7′12″W
,
1530 m
(
Aug–Sep
)
;
[4]
Fort Leaton
,
29°32′31″N
104°19′28″W
,
770 m
(
Jun
)
;
[5]
~
40km
E Redford
via
Hwy
170,
Grassy Banks Rest Area
,
725 m
, ~
29°17′01″N
103°53′12″W
(nd)
.
Jeff Davis Co.
:
[1]
~
16 km
NE
Valentine
,
Muerto Springs Ranch
(
Muerto Springs
),
30°40′50″N
104°20′22″W
,
1555 m
(Jul)
;
[2]
Davis
Mountains
Preserve
,
31°37′42″N
104°05′01″W
,
1785 m
(May)
.
Collection method(s).
a) baited pitfall trap (human feces); (b) incandescent light trap; (c) flight intercept trap; (d) *soil beneath wood rat nest.
Surface activity.
Nocturnal.
Habitat.
All zones in association with wood rats (
Neotoma
).
Comments.
This species is closely related to
O. velutinus
; and while males and larger females are easily distinguished, small or worn females can be difficult to identify if not associated with larger specimens or conspecific males. While they are attracted to human feces, they are collected in significantly larger numbers from soil beneath the living area of wood rat nests (
Halffter and Matthews 1966
;
Howden and Cartwright 1963
).
Onthophagus browni
is also common in southeastern
Arizona
, where it was apparently referred to as
O. hecate
by
Dajoz (1994)
. Bill Warner (pers. comm.) reports that
O. browni
and
O. velutinus
are separated by altitude/habitat in southeastern
Arizona
, the former species higher in the mountains and the latter at lower elevations in the flats and bajadas, a distribution pattern paralleled by
Copris arizonensis
and
C. macclevei
.