Geostiba (Sibiota) nebuligena Gusarov

Gusarov, Vladimir I., 2002, A revision of Nearctic species of the genus Geostiba Thomson, 1858 (Coleoptera: Staphylinidae: Aleocharinae), Zootaxa 81, pp. 1-88: 40-44

publication ID

http://doi.org/ 10.5281/zenodo.155701

publication LSID

lsid:zoobank.org:pub:B36587A1-248A-4194-8424-46C9BBA15606

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http://treatment.plazi.org/id/5B50E916-FFB9-3908-4D2D-FEA7FE0CFC04

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Plazi

scientific name

Geostiba (Sibiota) nebuligena Gusarov
status

 

6. Geostiba (Sibiota) nebuligena Gusarov  , sp. n. ( Figs. 146­168View FIGURES 146 ­ 151View FIGURES 152 ­ 156View FIGURES 157 ­ 168)

Type material. Holotype ,, UNITED STATES: Tennessee / North Carolina: Sevier Co. / Swain Co.: Appalachian Scenic Trail W of Clingmans Dome, 16 km S Gatlinburg, 35 ° 33.93 'N 83 ° 31.76 'W, 1800 m, in forest litter, Picea  , Abies  , Acer  , Fraxinus  , Oxalis (V.I.Gusarov)  , 22.vi. 2001 ( KSEM).

Paratypes: UNITED STATES: Tennessee / North Carolina: Sevier Co. / Swain Co.: 49 specimens, same data as the holotype ( KSEM, AMNH, CNCI, SPSU, FMNH); 27 specimens, Clingmans Dome [35 ° 33 ' 46 "N 83 ° 29 ' 55 "W] (J.S. & A.K.Ashe), 31.vii. 1991 ( KSEM); 2, ditto but 2000 m, Fraser Fir – Red Spruce forest (J.Bengston), 7.vii. 1974 ( FMNH); 83 specimens, Clingmans Dome Road, 14 km SSE Gatlinburg, 35 ° 35.46 'N 83 ° 28.28 'W, 1800 m, in forest litter, Picea rubens  , Abies fraseri  , Oxalis  , Rubus (V.I.Gusarov)  , 1.vi. 2001 ( KSEM, SPSU); 19 specimens, Appalachian National Scenic Trail, W of Clingmans Dome, 16 km S Gatlinburg, 35 ° 33.88 'N 83 ° 31.41 'W, 1930 m, in forest litter, Picea  , Abies  , Betula  , Oxalis (V.I.Gusarov)  , 22.vi. 2001 ( KSEM, SPSU); 2 ,, trail to Mt. Le Conte from Newfound Gap (W.S.Suter), 29.v. 1982 ( KSEM); 24 specimens, 0.5 km E Newfound Gap, 13 km SE Gatlinburg, 35 ° 36.44 'N 83 ° 25.37 'W, 1650 m, in forest litter, Picea rubens  , Oxalis  , Vaccinium (V.I.Gusarov)  , 1.vi. 2001 ( KSEM, SPSU); Tennessee: Sevier Co.: 13 specimens, Highway 441 & 71, 13 km SE Gatlinburg, 35 ° 37.3 'N 83 ° 26.3 'W, 1300 m, in forest litter, Rhododendron  , Tsuga  , Betula (V.I.Gusarov)  , 22.vi. 2001 ( SPSU);,, descending the Chimney Tops, 9­10 km SSE Gatlinburg, 35 ° 37.6­38.2 'N 83 ° 28.2 'W, 1040­1200 m, in forest litter, Tsuga  , Acer  , Rhododendron (V.I.Gusarov)  , 22.vi. 2001 ( SPSU);, Great Smokey Mts. National Park (W.Shear & F.Coyle), 24.x. 1969 ( FMNH); 18 specimens, Mt. Le Conte, half way up [35 ° 38.5 'N 83 ° 26.8 'W], deciduous forest, dry leaf litter near log (Lackey), 5.viii. 1956 ( FMNH, SPSU); North Carolina: Swain Co.:,, S slope of Clingmans Dome, 19 km NW Cherokee, 35 ° 33.66 'N 83 ° 29.9 'W, 2000 m, in forest litter, under young Abies  trees (V.I.Gusarov), 1.vi. 2001 ( SPSU);

Mislabeled material. 14 specimens, UNITED STATES: Michigan, Gogebic Co., Ottawa National Forest, Sylvania Tract, litter & mycelium (J.Wagner), 13.viii. 1977 ( KSEM). These specimens are identical with the types of G. nebuligena  in all external characters and in genitalia. G. nebuligena  is a wingless species restricted to the Great Smoky Mountains massif in the Southern Appalachians, and it is impossible for this species to occur also in Michigan, the area which was covered by ice sheet in Pleistocene. I consider these 14 specimens as mislabeled and exclude them from the types series, because their origin is unknown. Geostiba nebuligena  does not occur in Michigan.

Diagnosis. Geostiba nebuligena  can be distinguished from other Nearctic species of Geostiba  by having small eyes (temple length to eye length ratio 2.9 ­4.0), 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 abdominal tergum 7 in front of posterior margin and the shape of the aedeagus ( Figs. 152­161, 163 ­ 168View FIGURES 152 ­ 156View FIGURES 157 ­ 168) and the shape of the spermatheca ( Fig. 162View FIGURES 157 ­ 168).

Geostiba nebuligena  differs from closely related G. nimbicola  , G. pluvigena  and G. crepusculigena  in having apex of median lobe with strong apical denticle (in lateral view) ( Figs. 155­156View FIGURES 152 ­ 156, 102­ 103View FIGURES 100 ­ 107, 128­129View FIGURES 126 ­ 133, 176­ 177View FIGURES 174 ­ 177).

Description. Length 1.6­1.9 mm. Light brown to brown, antennae 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 3­4 times their diameter. Temple length to eye length ratio 2.9 ­4.0. Antennal article 2 longer than article 3, article 4 transverse (width to length ratio 1.6), articles 5­10 strongly transverse, last article as long as 9 and 10 combined (as in Fig. 17View FIGURES 8 ­ 17).

Pronotum as wide as long, width 0.37­0.40 mm, 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.

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 medial carinae in front of posterior margin. Male tergum 8 with two weak and short carinae in front of posterior margin, posterior margin convex ( Fig. 146View FIGURES 146 ­ 151). Male sternum 8 with convex posterior margin ( Fig. 147View FIGURES 146 ­ 151).

Female tergum 8 with convex posterior margin ( Fig. 148View FIGURES 146 ­ 151), sternum 8 with weakly emarginate posterior margin ( Figs. 149­150View FIGURES 146 ­ 151).

Aedeagus as in Figs. 152­161, 163 ­ 168View FIGURES 152 ­ 156View FIGURES 157 ­ 168. Apex of median lobe in ventral view narrow, its outline doubly emarginate apically ( Figs. 152­154View FIGURES 152 ­ 156), in lateral view strait, with strong apical denticle ventrally ( Figs. 155­156View FIGURES 152 ­ 156), distal diverticula of internal sac in ventral view broad ( Figs. 160­161View FIGURES 157 ­ 168).

Spermatheca as in Fig. 162View FIGURES 157 ­ 168.

Distribution. Known from the Great Smoky Mountains massif (Tennessee and North Carolina) ( Figs. 338View FIGURE 338, 340View FIGURE 340).

Natural History. Geostiba nebuligena  was collected at altitudes above 1000 m in leaf litter in pure conifer or mixed forest with red spruce ( Picea rubens  ), Fraser’s fir ( Abies fraseri  ) or hemlock.

Etymology. The specific name is derived from the Latin noun nebula (mist, fog) and the verb gigno (to be born, to arise). It refers to fogs in the Great Smoky Mountains where the species occurs.

AMNH

American Museum of Natural History

CNCI

Canadian National Collection Insects

FMNH

Field Museum of Natural History