A revision of Nearctic species of the genus Geostiba Thomson, 1858 (Coleoptera: Staphylinidae: Aleocharinae)
Author
Gusarov, Vladimir I.
text
Zootaxa
2002
81
1
88
journal article
51429
10.5281/zenodo.155701
b947e6c9-d6cf-4988-a098-5e01dd69a888
11755326
155701
2.
Geostiba
(
Sibiota
)
bicarinata
Lohse & Smetana, 1988
(
Figs. 5171
)
Geostiba bicarinata
Lohse & Smetana, 1988
: 273
,
ex parte.
Geostiba bicarinata
:
Pace, 1997
: 104
.
Type
material.
Holotype
,,
UNITED STATES
: North Carolina:
Haywood Co.: Richland Balsam Mt. [
35°22'01"N
82°59'26"W
],
18601950 m
(A.Smetana),
27.v.1986
(
CNCI
); allotype,, ditto;
paratypes
: 5, 3, ditto; 4,, ditto but
18501950 m
,
25.v.1986
(all
CNCI
).
Some
paratypes
of
G. bicarinata
belong to other species:
Geostiba pluvigena
Gusarov
,
sp. n.
:, North Carolina: Haywood Co., Blue Ridge Parkway, Browning Knob Mt.,
18301890 m
(A.Smetana),
28.v.1986
(examined) (
CNCI
). Two other
paratypes
were not found in
CNCI
, but their locality data are listed by
Lohse and Smetana (1988: 275)
. My collecting efforts demonstrated that these
paratypes
originate from the mountain massifs were
G. bicarinata
does not occur. These presumably misidentified
paratypes
belong to
G. alticola
(one specimen, Buncombe Co.: base of Mt. Mitchell at Blue Ridge Parkway, about
1650 m
(A.Smetana),
3.vi.1986
) and
G. nimbicola
(one specimen, Great Smoky Mountains National Park, Clingmans Dome,
19502020 m
, (A.Smetana)
2.vi.1986
).
Additional material.
UNITED STATES
: North Carolina:
Haywood Co.: 2, Richland Balsam Mt.,
1829m
(J.F. Cornell), fir duff,
26.iv.1974
(
KSEM
); Haywood Co. / Jackson Co.:
15 specimens
, Richland Balsam Mt., near summit,
14 km
S Waynesville,
35°22.50'N
82°59.43'W
,
1950 m
, in forest litter,
Picea rubens
,
Abies fraseri
,
Vaccinium
(V.I.Gusarov)
,
3.vi.2001
;
12 specimens
, ditto but W slope of Richland Balsam Mt.,
35°22.28'N
82°59.42'W
,
1900 m
,
Picea rubens
,
Abies fraseri
;
15 specimens
, ditto but S slope of Richland Balsam Mt.,
35°21.04'N
82°59.56'W
,
1850 m
,
Picea rubens
,
Abies fraseri
,
Betula
,
Oxalis
;
14 specimens
, Blue Ridge Parkway,
11 km
SSW Waynesville,
35°23.3'N
83°02.43'W
,
1800 m
, in forest litter,
Picea rubens
,
Abies fraseri
,
Betula
,
Oxalis
(V.I.Gusarov)
,
2.vi.2001
;
10 specimens
, ditto but
13 km
S Waynesville,
35°22.12'N
82°59.65'W
,
1800 m
, in forest litter,
Picea rubens
,
Abies fraseri
,
Oxalis
(V.I.Gusarov)
,
3.vi.2001
(all –
KSEM
and
SPSU
);, Blue Ridge Parkway, Grassy Ridge Mine Overlook,
8 km
SSW Waynesville,
35°24.94'N
83°02.80'W
,
1650 m
, in forest litter,
Tsuga
,
Quercus
,
Betula
(V.I.Gusarov)
,
2.vi.2001
; Haywood Co. / Buncombe Co.:, Little Pisgah Mt., near summit,
35°25.48'N
82°45.51'W
,
17301760 m
, in forest litter,
Fagus
,
Quercus
,
Rhododendron
(V.I.Gusarov)
,
20.ix.2001
(all –
SPSU
).
FIGURES 5156
. Abdominal segments 78 of
Geostiba bicarinata
Lohse & Smetana
(Richland Balsam Mountain, North Carolina). 51 – male tergum 8; 52 – male sternum 8; 53 – female tergum 8; 54 – female sternum 8, 55 – apex of female sternum 8; 56 – medial portion of male tergum 7, posterior down. Scale bar 0.2 mm (5154, 56), 0.1 mm (55).
Diagnosis.
Geostiba bicarinata
can be distinguished from other Nearctic species of
Geostiba
by having small eyes (temple length to eye length ratio 3.85.0), pronotal pubescence of
type
V, reduced wings, short elytra (pronotum length to elytron length ratio 1.3), the presence of two short parallel carinae in the middle of male abdominal tergum
7 in
front of posterior margin, the shape of the aedeagus (
Figs. 5764, 6671
) and the shape of the spermatheca (
Fig. 65
).
Geostiba bicarinata
is closely related to
G. graveyardensis
but differs in the following: the apex of median lobe in lateral view not bent ventrally (
Figs. 5960
,
7980
), in ventral view without apical process (
Figs. 5758
,
7778
).
FIGURES 5760
. Aedeagus of
Geostiba bicarinata
Lohse & Smetana
(Richland Balsam Mountain, North Carolina). 57 – median lobe, ventral view; 58 – apex of median lobe, ventral view; 59 – median lobe, lateral view; 60 – apex of median lobe, lateral view. Scale bar 0.2 mm (57, 59), 0.1 mm (58, 60).
Description.
Length 2.0
2.3 mm
. Dark brown, elytra often lighter, antennae brown, legs and mouthparts yellowish brown. Body parallelsided.
Head as wide as long, surface on disk with fine isodiametric microsculpture, puncturation very fine, distance between punctures equal to 34 times their diameter. Temple length to eye length ratio 3.85.0. Antennal article 2 longer than article 3, article 4 slightly transverse, 510 transverse, last article as long as 9 and 10 combined (as in
Fig. 16
).
Pronotum slightly transverse, width
0.40.46 mm
, width to length ratio 1.1, wider than head (pronotal width to head width ratio 1.2); microsculpture and puncturation as on head. Pronotal pubescence of
type
V. Elytra measured from humeral angle shorter than pronotum (pronotal length to elytral length ratio 1.3), wider than long (1.5), with fine isodiametric microsculpture and fine, asperate puncturation, distance between punctures equals 23 times their diameter. Elytral suture behind scutellum slightly raised in both sexes. Wings reduced to short vestiges, shorter than elytra.
FIGURES 6171
. Genitalia of
Geostiba bicarinata
Lohse & Smetana
(Richland Balsam Mountain, North Carolina). 61 – details of internal sac retracted into median lobe, ventral view; 62 – copulatory piece of internal sac, dorsal view; 63 – medial lamellae of internal sac, ventral view; 64 – everted internal sac, ventral view; 65 – spermatheca; 6667 – details of internal sac retracted into median lobe, lateral view; 68 – copulatory piece of internal sac, lateral view; 69 – medial lamella of internal sac, lateral view; 70 – everted internal sac, lateral view; 71 – apex of left paramere, side facing median lobe. Scale bar 0.2 mm (61, 64, 6667, 70), 0.1 mm (6263, 65, 6869, 71).
Abdominal terga with fine microsculpture of transverse meshes, with fine and sparse puncturation, puncturation becoming finer towards abdomen apex, on terga 35 distance between punctures equals 37 times their diameter. Tergum 7 without white edge.
In males pronotum slightly flattened on disc. Male tergum 7 with two medial carinae in front of posterior margin. Male tergum 8 with two or four weak and short carinae in front of posterior margin, and two weak projections at posterior margin (
Fig. 51
). Male sternum 8 with convex posterior margin (
Fig. 52
).
Female tergum 8 with slightly convex posterior margin (
Fig. 53
), posterior margin of sternum 8 slightly concave medially (
Figs. 5455
).
Aedeagus as in
Figs. 5764, 6671
. Apex of median lobe in ventral view broad, with convex outline, without apical process (
Figs. 5758
), in lateral view not bent ventrally (
Figs. 5960
), distal diverticula of internal sac with numerous denticles (
Figs. 61, 64, 70
), in ventral view narrow (
Fig. 64
), in lateral view broad (
Fig. 70
).
Spermatheca as in
Fig. 65
.
Distribution.
Known from the Great Balsam Mountains and Little Pisgah Mountain (North Carolina) (
Figs. 338
,
340
).
Natural History.
Geostiba bicarinata
was collected by sifting forest litter at altitudes above
1600 m
mostly in pure conifer or mixed forest with red spruce (
Picea rubens
) and Fraser’s fir (
Abies fraseri
).