Geostiba (Sibiota) balsamensis Pace 1997
Creators: name: Gusarov, Vladimir I.
Publisher: name: Zenodo
Year: 2002
Subjects: Biodiversity
Taxonomy

description: 8. Geostiba (Sibiota) balsamensis Pace, 1997 (Figs. 187­212)
Geostiba (Lioglutosipalia) balsamensis Pace, 1997: 104.
Material. UNITED STATES: North Carolina: Swain Co.: 8 specimens, SW slope of Cataloochee Balsam Mt., Balsam Mt. Road, 20 km NW Waynesville, 35°34.3'N 83°10.9'W, 1700 m, in forest litter, Picea rubens, Acer, Fagus, Betula (V.I.Gusarov), 2.vi.2001; 3 specimens, Balsam Mt. Road, 17 km NWW Waynesville, 35°32.79'N 83°10.0'W, 1650 m, in forest litter, Picea rubens, Abies fraseri, Fagus, Betula (V.I.Gusarov), 2.vi.2001; Swain Co. / Haywood Co.: 2 specimens, Balsam Mt. Road, Masonic Monument, 17 km NWW Waynesville, 35°32.2'N 83°10.2'W, 1400 m, in forest litter, Tsuga, Acer, Rhododendron (V.I.Gusarov), 2.vi.2001; Haywood Co. / Jackson Co.: 5 specimens, junction of Balsam Mt. Road and Blue Ridge Parkway, 17 km W Waynesville, 35°29.72'N 83°10.43'W, 1600 m, in forest litter, Picea rubens, Fagus, Betula, Rhododendron (V.I.Gusarov), 2.vi.2001 (all in KSEM);, N slope of Waterrock Knob, 13 km W Waynesville, 35°28.0'N 83°08.2'W, 1900 m, in forest litter, Picea rubens, Abies fraseri (V.I.Gusarov), 2.vi.2001 (SPSU); Haywood Co.:, Blue Ridge Parkway, 15 km W Waynesville, 35°30.34'N 83°09.34'W, 1350 m, in forest litter (V.I.Gusarov), 20.viii.1998 (SPSU).
Type locality. UNITED STATES: North Carolina: Swain Co.: Cataloochee Balsam Mt., Heintooga overlook (Pace 1997). Pace cites this locality as “Heintoge Overlot”. This is one of the parking overlooks at the Heintooga spur of the Blue Ridge Parkway (Balsam Mountain Road).
Diagnosis. Geostiba balsamensis can be distinguished from other Nearctic species of Geostiba by having small eyes (temple length to eye length ratio 3.0­3.7), pronotal pubescence of type V, reduced wings, short elytra (pronotum length to elytron length ratio 1.4), the presence of two weak and short parallel carinae in the middle of abdominal tergum 7 in front of posterior margin, the shape of the aedeagus (Figs. 193­202, 204­212) and the shape of the spermatheca (Fig. 203).
Geostiba balsamensis differs from G. nubigena in having two week carinae on male tergum 7 and wider apex of median lobe (Figs. 193­194, 219­220, 223­229).
Description. Length 1.8­2.2 mm. Body and antennae brownish yellow to light brown, legs and mouthparts brownish yellow. Body parallel­sided.
Head as wide as long, surface on disk with fine isodiametric microsculpture, puncturation very fine, distance between punctures equal to 2­4 times their diameter. Temple length to eye length ratio 3.0­3.8. Antennal article 2 longer than article 3, articles 4­10 transverse to strongly transverse, last article as long as 9 and 10 combined.
Pronotum as wide as long, width 0.36­0.39 mm, wider than head (pronotal width to head width ratio 1.1); 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 1.4), wider than long (1.6), 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.
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 3­6 times their diameter. Tergum 7 without white edge.
Male tergum 7 with two very weak medial carinae in front of posterior margin. Posterior margin of male tergum 8 and sternum 8 convex (Figs. 187­188).
Female tergum 8 with convex posterior margin (Fig. 189), posterior margin of female sternum 8 concave medially (Figs. 190­191).
Aedeagus as in Figs. 193­202, 204­212. Apex of median lobe in ventral view broad (Figs. 193­194), in lateral view strait (Figs. 195­196).
CP – copulatory piece, DD – distal diverticula of internal sac, LW – lateral wall of internal sac, ML – medial lamellae, PD – proximal diverticula of internal sac.
Spermatheca as in Fig. 203.
Distribution. Known from the Plott Balsams – Cataloochee Divide massif (North Carolina) (Figs. 338, 340).
Natural History. Geostiba balsamensis was collected at altitudes of 1300­1900 m in leaf litter in pure conifer or mixed forest with red spruce (Picea rubens), Fraser’s fir (Abies fraseri) or hemlock.
description: Published as part of Gusarov, Vladimir I., 2002, A revision of Nearctic species of the genus Geostiba Thomson, 1858 (Coleoptera: Staphylinidae: Aleocharinae), pp. 1-88 in Zootaxa 81 on pages 47-52, DOI: 10.5281/zenodo.155701