Geostiba (Sibiota) nubigena Lohse & Smetana, 1988

Gusarov, Vladimir I., 2002, A revision of Nearctic species of the genus Geostiba Thomson, 1858 (Coleoptera: Staphylinidae: Aleocharinae), Zootaxa 81, pp. 1-88 : 52-57

9. Geostiba (Sibiota) nubigena Lohse & Smetana, 1988 ( Figs. 213­246 )

Geostiba nubigena Lohse & Smetana, 1988: 273 . Geostiba nubigena: Pace, 1997: 104 .

Type material. Holotype ,, UNITED STATES: North Carolina: Haywood Co.: Richland Balsam Mt. [35°22'01"N 82°59'26"W], 1850­1950 m (A.Smetana), 25.v.1986 ( CNCI); allotype,, ditto; paratypes: 4, ditto; 3,, ditto but 1860­1950 m, 27.v.1986;,, Shining Rock Mt. [35°22'05"N 82°51'45"W], 1500 m (A.Smetana), 31.v.1986 (all ­ CNCI).

Additional material. UNITED STATES: North Carolina: Haywood Co.:, same data as the holotype ( CNCI); 14 specimens, Black Balsam Knob Road N of Blue Ridge Parkway, 21 km SSE Waynesville, 35°19.1'N 82°52.6'W, 1800 m, in forest litter, Picea (V.I.Gusarov) , 20.ix.2001; 12 specimens, Blue Ridge Parkway above Graveyard Fields parking, right bank of the river, 22 km SE Waynesville, 35°19.1'N 82°50.7'W, 1600 m, in forest litter, Picea , Betula (V.I.Gusarov) , 20.ix.2001; 18 specimens, Blue Ridge Parkway at Graveyard Fields, right bank of the river, 22 km SE Waynesville, 35°19.2'N 82°50.7'W, 1550 m, in forest litter by the river, Picea , Betula , Rhododendron , Vaccinium (V.I.Gusarov) , 20.ix.2001; 15 specimens, Graveyard Fields, left bank of the river, 22 km SE Waynesville, 35°19.57'N 82°51.01'W, 1570 m, in forest litter, Picea (V.I.Gusarov) , 20.ix.2001; 2 specimens, Graveyard Fields, right bank of the river, 23 km SE Waynesville, 35°19.24'N 82°50.87'W, 1600 m, in forest litter, Rhododendron (V.I.Gusarov) , 24.vi.2001; 2 specimens, environs of Sam Knob, 21 km SE Waynesville, 35°19.62'N 82°53.08'W, 1800 m, mountain meadows, in dead grass (V.I.Gusarov), 24.vi.2001; 6 specimens, Highway 215, 21 km SSE Waynesville, 35°18.80'N 82°54.78'W, 1500 m, in forest litter, Picea , Betula , Rhododendron (V.I.Gusarov) , 24.vi.2001; Haywood Co. / Jackson Co.:, 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; 14 specimens, Blue Ridge Parkway, 21 km SSE Waynesville, 35°18.42'N 82°56.47'W, 1600 m, in forest litter, Picea rubens , Abies fraseri , Oxalis (V.I.Gusarov) , 3.vi.2001; 9 specimens, ditto but 13 km S Waynesville, 35°22.12'N 82°59.65'W, 1800 m; 12 specimens, ditto but 11 km SSW Waynesville, 35°23.3'N 83°02'W, 1800 m, in forest litter, Picea rubens , Abies fraseri , Betula , Oxalis , 2.vi.2001; 3 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, Va c ci n iu m (V.I.Gusarov), 3.vi.2001; 2 specimens, ditto but W slope of Richland Balsam Mt., 35°22.28'N 82°59.42'W, 1900 m, in forest litter, Picea rubens , Abies fraseri ; 2 specimens, ditto but S slope of Richland Balsam Mt., 35°21.04'N 82°59.56'W, 1850 m, in forest litter, Picea rubens , Abies fraseri , Betula , Oxalis ; Haywood Co. / Transylvania Co.: 3 specimens, Blue Ridge Parkway, 23 km SE Waynesville, 35°19.13'N 82°50.08'W, 1500 m, in forest litter, Quercus , Picea rubens , Tsuga , Fagus , Acer , Rhododendron , Vaccinium (V.I.Gusarov) , 3.vi.2001;, Blue Ridge Parkway, 22 km SSE Waynesville, 35°18.32'N 82°53.49'W, 1700 m, in forest litter, Picea , Abies , Quercus , Betula , Acer (V.I.Gusarov) , 24.vi.2001; 24 specimens, Blue Ridge Parkway, 23 km SEE Waynesville, 35°25.2'N 82°45.0'W, 1550 m, in forest litter, Picea , Rhododendron , Quercus (V.I.Gusarov) , 20.ix.2001; Haywood Co. / Buncombe Co.: 6 specimens, Little Pisgah Mountain near summit, 22 km SEE Waynesville, 35°25.48'N 82°45.51'W, 1730­1760 m, in forest litter, Fagus , Quercus , Rhododendron (V.I.Gusarov) , 20.ix.2001; 12 specimens, S slope of Little Pisgah Mountain, 22 km SEE Waynesville, 35°25.05'N 82°45.81'W, 1650 m, in forest litter, Picea , Betula , Acer (V.I.Gusarov) , 20.ix.2001; Macon Co. / Clay Co.:, Blue Ridge, Appalachian National Scenic Trail, 21.5 km SW Franklin, 35°01.64'N 83°32.16'W, 1620 m, in forest litter, Quercus , Kalmia latifolia (V.I.Gusarov) , 23.vi.2001 (all – KSEM and SPSU).

Diagnosis. Geostiba nubigena can be distinguished from other Nearctic species of Geostiba by having small eyes (temple length to eye length ratio 4.3­6.0), pronotal pubescence of type V, reduced wings, short elytra (pronotum length to elytron length ratio 1.3), the absence of carinae on abdominal tergum 7, the shape of the aedeagus ( Figs. 219­234, 237­246 ) and the shape of the spermatheca ( Figs. 235­236 ).

Geostiba nubigena differs from G. balsamensis in lacking the carinae on male tergum 7 and in having more narrow apex of median lobe ( Figs. 219­220, 223­229 , 193­194 ); from G. coeligena in having more narrow median lobe of aedeagus (in ventral view) ( Figs. 219­220, 223­229 , 249­250 ), long distal diverticula ( Figs. 233­234 , 253, 256 ) and small proximal diverticula of internal sac ( Figs. 234 , 253, 257­258 ).

Description. Length 1.8­2.2 mm. Uniformly brownish yellow, in some specimens abdominal segments 3­6 light brown. 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 4.3­6.0. Antennal article 2 longer than article 3, article 4­10 transverse to strongly transverse, last article as long as 9 and 10 combined.

Pronotum as wide as long, width 0.34­0.39 mm, wider than head (pronotal width to head width ratio 1.1); microsculpture and puncturation as on head. Elytra measured from humeral angle shorter than pronotum (pronotal length to elytral length ratio 1.3), wider than long (1.4), with fine isodiametric microsculpture and fine asperate puncturation, distance between punctures equals 1­2 times their diameter. Pronotal pubescence of type V.

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 2­5 times their diameter. Tergum 7 without white edge.

Male tergum 7 without carinae. Posterior margin of male tergum 8 slightly convex ( Fig. 213 ). Posterior margin of male sternum 8 convex ( Fig. 214 ).

Female tergum 8 with slightly convex posterior margin ( Fig. 215 ), sternum 8 with slightly emarginate posterior margin ( Figs. 216­217 ).

Aedeagus as in Figs. 219­234, 237­246 . Apex of median lobe in lateral view strait ( Figs. 221­222 ).

Spermatheca as in Figs. 235­236 .

Distribution and variability. Known from the Great Balsam Mountains – Pisgah Ridge massif and from Standing Indian in the Blue Ridge (North Carolina) ( Figs. 338 , 340 ). Geostiba nubigena is variable in the shape of aedeagus median lobe ( Figs. 219­229 ). Forms from different mountains have different shape of median lobe, but when specimens from many localities were compared no cline or clear hiatus between different forms were found. The locality on Standing Indian is quite distant from other localities in the Great Balsam Mts.­Pisgah Ridge massif. However in aedeagus shape the specimens from Standing Indian fall within the range of variability of G. nubigena .

Natural History. Geostiba nubigena was collected at altitudes above 1500 m in leaf litter, mostly in forests with red spruce ( Picea rubens ) and Fraser’s fir ( Abies fraseri ), in some localities in forests with oak, beech, rhododendron and mountain laurel but without any conifers.

Figures

FIGURE 338. Geographical distribution of twelve species of Geostiba in the Southern Appalachians. Isohypses 1200 m and 1500 m are shown. Areas above 1500 m are solid black.

FIGURE 340. Detailed geographical distribution of Geostiba bicarinata Lohse & Smetana (2), G. graveyardensis Pace (3), G. nimbicola Lohse & Smetana (4), G. pluvigena Gusarov, sp. n. (5), G. nebuligena Gusarov, sp. n. (6), G. crepusculigena Gusarov, sp. n. (7), G. balsamensis Pace (8), G. nubigena Lohse & Smetana (9), G. coeligena Gusarov, sp. n. (10) in the Southern Appalachians. Isohypses 1200 m and 1500 m are shown. Areas above 1500 m are solid black.

FIGURES 213 ­ 218. Abdominal segments 7 ­ 8 of Geostiba nubigena Lohse & Smetana (Richland Balsam Mountain (213 ­ 215, 218) and Blue Ridge Parkway (216 ­ 217), North Carolina). 213 – male tergum 8; 214 – male sternum 8; 215 – female tergum 8; 216 – female sternum 8, 217 – apex of female sternum 8; 218 – medial portion of female tergum 7, posterior down. Scale bar 0.2 mm (213 ­ 216, 218), 0.1 mm (217).

FIGURES 219 ­ 229. Aedeagus of Geostiba nubigena Lohse & Smetana (Richland Balsam Mountain (219 ­ 222), Blue Ridge Parkway (223), Graveyard Fields (224 ­ 227) and Grassy Ridge Mine Overlook (228 ­ 229), North Carolina). 219, 224, 226, 228 – median lobe, ventral view; 220, 223, 225, 227, 229 – apex of median lobe, ventral view; 221 – median lobe, lateral view; 222 – apex of median lobe, lateral view. Scale bar 0.2 mm (219, 221, 224, 226, 228), 0.1 mm (220, 222 ­ 223, 225, 227, 229).

FIGURES 230 ­ 246. Genitalia of Geostiba nubigena Lohse & Smetana (Richland Balsam Mountain (230 ­ 231, 234 ­ 235, 237 ­ 238, 242, 246) and Blue Ridge Parkway (232 ­ 233, 236, 239 ­ 241, 243 ­ 245), North Carolina). 230 – details of internal sac retracted into median lobe, ventral view; 231 – copulatory piece of internal sac, dorsal view; 232 – medial lamellae of internal sac, ventral view; 233 – distal diverticula of everted internal sac, ventral view; 234 – everted internal sac, ventral view; 235 ­ 236 – spermatheca; 237 ­ 238 – details of internal sac retracted into median lobe, lateral view; 239 – partially everted internal sac, lateral view; 240 – details of internal sac inside partially everted internal sac, lateral view; 241 – everted internal sac, lateral view; 242 – completely everted internal sac, lateral view; 243 – copulatory piece of internal sac, lateral view; 244 – medial lamella of internal sac, lateral view; 245 – right distal diverticulum of everted internal sac, lateral view; 246 – apex of left paramere, side facing median lobe. Scale bar 0.2 mm (230, 234, 237 ­ 242), 0.1 mm (231 ­ 233, 235 ­ 236, 243 ­ 246).

FIGURES 193 ­ 196. Aedeagus of Geostiba balsamensis Pace (Cataloochee Balsam Mountain, North Carolina). 193 – median lobe, ventral view; 194 – apex of median lobe, ventral view; 195 – median lobe, lateral view; 196 – apex of median lobe, lateral view. Scale bar 0.2 mm (193, 195), 0.1 mm (194, 196).

FIGURES 247 ­ 252. Abdominal segment 8 and aedeagus of Geostiba coeligena Gusarov, sp. n. (paratype). 247 – male tergum 8; 248 – male sternum 8; 249 – median lobe, ventral view; 250 – apex of median lobe, ventral view; 251 – median lobe, lateral view; 252 – apex of median lobe, lateral view. Scale bar 0.2 mm (247 ­ 249, 251), 0.1 mm (250, 252).

FIGURES 253 ­ 261. Aedeagus of Geostiba coeligena Gusarov, sp. n. (253, 256 ­ 258, 260 ­ 261 – paratype, 254 ­ 255, 259 ­ holotype). 253 – everted internal sac, ventral view; 254 – copulatory piece of internal sac, dorsal view; 255 – medial lamellae of internal sac, ventral view; 256 – distal diverticula of everted internal sac, ventral view; 257 – left proximal diverticulum of everted internal sac, ventral view; 258 – everted internal sac, lateral view; 259 – copulatory piece of internal sac, lateral view; 260 – medial lamella of internal sac, lateral view; 261 – apex of left paramere, side facing median lobe. Scale bar 0.2 mm (253, 258), 0.1 mm (254 ­ 257, 259 ­ 261).