Description Of A New Spilodiscus Lewis, And A Reanalysis Of Spilodiscus Phylogeny (Coleoptera: Histeridae)
Author
Caterino, Michael S.
Department of Entomology The Natural History Museum, Cromwell Rd. London SW 7 5 BD, UNITED KINGDOM
michc@nhm.ac.uk
Author
Kovarik, Peter W.
Center for Biological Control Florida A & M University Tallahassee, FL 32307, U. S. A.
pkovarik@famu.edu
text
The Coleopterists Bulletin
2001
2001-06-01
55
2
134
143
journal article
10.1649/0010-065x(2001)055[0134:doansl]2.0.co;2
1938-4394
4891441
Spilodiscus skelleyi
Caterino & Kovarik
new species
Type Material (total
9 specimens
).
Holotype
male: ‘‘
FLORIDA
:
Putnam Co.
K. Ordway Pres.
,
3 mi.
E.
Melrose
,
5–26.IX.1998
,
P. Skelley
, barrier
pitfall
trap’’ deposited in
Florida State
Collection of Arthopods
.
Paratype
male (1): ‘‘
FLORIDA
:
Levy Co.
,
4 mi.
SW Archer on Route
24, 25.
III
.–6.
VI
.1999,
P. Skelley
, coll., ex.
Barrier
pitfall
trap’’;
paratype
female (1): ‘‘FL:
Putnam Co.
,
3 mi.
E Melrose
,
K. Ordway Preserve
, 20VI97, P.E.S. [
P.E. Skelley
]’’/‘‘berlese of litter around deer dung in sand hill meadow’’;
paratype
female (1): ‘‘
FLORIDA
:
Levy Co.
,
4 mi.
SW Archer
,
13.X.1996
,
P.W. Kovarik
, collector’’/ ‘‘ex. sand in vicinity of ant nests’’ (see
Fig. 3
);
paratype
females (2): ‘‘FLOR IDA:
Levy Co.
,
4 mi.
SW Archer on Route
24, 25.
III
.6.
VI
.1999,
P. Skelley
, coll., ex.
Barrier
pitfall
trap’’;
paratypes
of undetermined sex (3): ‘‘
FLORIDA
:
Levy Co.
,
4 mi.
SW Archer on Route
24, 25.
III
.6.
VI
.1999,
P. Skelley
, coll., ex.
Barrier
pitfall
trap’
’.
Paratypes
in
United States
National Museum
(1),
Field Museum
(1),
The Natural History Museum
,
London
(1),
Caterino
collection (2), and
Kovarik
collection (3)
.
Description.
Small [avg. length
2.3 mm
; avg. width
1.8 mm
;
n 5 9
]; body round in outline (
Figs. 1–2
); entirely black with rufescent tinge particularly on elytra.
Frons minutely punctate; frontal stria faintly bisinuate pointing forward at middle; frequently a short transverse striole in the middle of the frontal disk; labrum onehalf as long as wide; mandibles convex above, each with bidentate tooth on incisor (
Figs. 3–4
); antennal club small.
Inner and outer lateral pronotal striae complete; hypomeron setose; prosternal keel longitudinally striate or not; prosternal lobe rounded apically; protibiae acutely bidentate (or rarely unidentate), each tooth with apical spine; posterior surface of protibiae smooth to minutely punctate.
Figs. 1–4.
Spilodiscus
skelley
i.
1
) Dorsal;
2
) ventral;
3–4
) anterior. Arrow in fig. 4 indicates the mandibular dentation. Scale bar 5 1.0 mm for Figures 2–3 and 0.5 mm for Figure 4.
Elytra black or faintly rufescent laterally; outer subhumeral stria absent; inner subhumeral stria faintly impressed at elytral apex or absent; striae 1–2 complete; stria 3 complete or rarely interrupted; stria 4 absent or faintly visible at elytral base; stria 5 absent; sutural stria complete. Meso and metatibia with 2 longitudinal series of spines.
Propygidium and pygidium with shallow punctures separated by slightly more than their diameters.
Male genitalia (
Figs. 5–13
). Aedeagus with basal piece short, approximately onethird tegmenal length; tegmen expanded laterally in apical onehalf; lateral arms of median lobe armature feebly sinuate, hooked apically; dorsal projec tions of armature twothirds length of lateral arms, divergent apically; gonopore at base of armature.
Figs. 5–13.
Male genitalia of
Spilodiscus skelleyi
.
5
) Dorsal;
6
) ventral;
7
) lateral views of the 8
th
abdominal segment.
8
) Dorsal;
9
) ventral;
10
) lateral views of the 9
th
and 10
th
abdominal segments.
11
) Dorsal;
12
) ventral;
13
) lateral views of the aedeagus. Scale bar 5 0.5 mm.
Diagnosis.
This species’ strongly bidentate protibiae and aedeagus unequivocally identify it as a
Spilodiscus
and it is easily separated from all other
Spilodiscus
by its small size, mandibular dentation, and lack of red maculations.
Spilodiscus flohri
is similar in size to
S. skelleyi
and has dentate mandibles, but has red maculate elytra and is not known to have prosternal striae. The only other all black
Spilodiscus
with which
S. skelleyi
may be sympatric,
S. floridanus
,
is nearly three times its size.
Distribution
(
Fig. 14
).
S. skelleyi
is known only from 2 locations in northern
Florida
.
Etymology.
We have named this species for Paul Skelley, the collector of the majority of the
type
series, in recognition of his invaluable and continuing contributions to the knowledge of histerid biology.
Fig. 14.
Map of Florida indicating the 2 known localities for
Spilodiscus skelleyi
.
Remarks.
The habits of
S. skelleyi
are unknown. Although
one paratype specimen
was collected near a nest of
Pheidole
ants, additional sampling has revealed no additional associated specimens (P. Skelley, pers. comm.). We consider it unlikely that this is the beetle’s primary habitat. Pocket gopher (
Geomys pinetus
Rafinesque
) and Gopher tortoise [
Gopherus polyphemus
(Daudin)
] have likewise been widely surveyed in the same area but have produced no additional specimens. Burrows of mice (
Peromyscus
spp.
) are locally common but have not yet been specifically sampled and remain a possibility.