Geostiba (Sibiota) graveyardensis Pace, 1997

Gusarov, Vladimir I., 2002, A revision of Nearctic species of the genus Geostiba Thomson, 1858 (Coleoptera: Staphylinidae: Aleocharinae), Zootaxa 81, pp. 1-88 : 28-31

3. Geostiba (Sibiota) graveyardensis Pace, 1997 ( Figs. 72­93 )

Geostiba (Ditroposipalia) graveyardensis Pace, 1997: 102 .

Material. UNITED STATES: North Carolina: Haywood Co.: 2 specimens, Graveyard Fields at Blue Ridge Parkway, 22 km SE Waynesville, right bank of the river, 35°19.2'N 82°50.7'W, 1550 m, in forest litter by the river, Picea , Betula , Rhododendron (V.I.Gusarov) , 20.ix.2001; 48 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 (all KSEM and SPSU).

Type locality. UNITED STATES: North Carolina: Haywood Co.: Graveyard Fields at Blue Ridge Parkway ( Pace 1997).

Diagnosis. Geostiba graveyardensis can be distinguished from other Nearctic species of Geostiba by having small eyes (temple length to eye length ratio 2.8­3.8), 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, the shape of the aedeagus ( Figs. 77­85, 87­93 ) and the shape of the spermatheca ( Fig. 86 ).

Geostiba graveyardensis is closely related to G. bicarinata but differs in the following: the apex of median lobe in lateral view bent ventrally ( Figs. 79­80 , 59­60 ), in ventral view with apical process ( Figs. 77­78 , 57­58 ).

Description. Length 1.9­2.3 mm. Brown or dark brown, elytra and apex of abdomen often lighter, 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 2.8­3.8. Antennal article 2 longer than article 3, article 4 slightly transverse, 5­10 transverse, last article longer than 9 and 10 combined (as in Fig. 16 ).

Pronotum slightly transverse, width 0.41­0.44 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.

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.

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, posterior margin convex ( Fig. 72 ). Male sternum 8 with convex posterior margin ( Fig. 73 ).

Female tergum 8 with convex posterior margin ( Fig. 74 ), posterior margin of sternum 8 concave medially ( Figs. 75­76 ).

Aedeagus as in Figs. 77­85, 87­93 . Apex of median lobe in ventral view with apical process ( Figs. 77­78 ), in lateral view bent ventrally ( Figs. 79­80 ), distal diverticula of internal sac with numerous denticles ( Figs. 81, 84, 91­92 ), in ventral view narrow ( Figs. 84­85 ), in lateral view broad ( Figs. 91­92 ).

Spermatheca as in Fig. 86 .

Distribution. Known from the Graveyard Ridge and Black Balsam Knob in the Great Balsam Mountains – Pisgah Ridge massif (North Carolina) ( Figs. 338 , 340 ).

Natural History. Geostiba graveyardensis was collected by sifting forest litter at altitudes from 1500 m to 1800 m in pure conifer or mixed forest with red spruce ( Picea rubens ).

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 72 ­ 76. Abdominal segment 8 of Geostiba graveyardensis Pace (Graveyard Fields, North Carolina). 72 – male tergum 8; 73 – male sternum 8; 74 – female tergum 8; 75 – female sternum 8, 76 – apex of female sternum 8. Scale bar 0.2 mm (72 ­ 75), 0.1 mm (76).

FIGURES 77 ­ 80. Aedeagus of Geostiba graveyardensis Pace (Graveyard Fields, North Carolina). 77 – median lobe, ventral view; 78 – apex of median lobe, ventral view; 79 – median lobe, lateral view; 80 – apex of median lobe, lateral view. Scale bar 0.2 mm (77, 79), 0.1 mm (78, 80).

FIGURES 81 ­ 93. Genitalia of Geostiba graveyardensis Pace (Graveyard Fields (81, 84 ­ 88, 91 ­ 93) and Black Balsam Knob Road (82 ­ 83, 89 ­ 90), North Carolina). 81 – details of internal sac retracted into median lobe, ventral view; 82 – copulatory piece of internal sac, dorsal view; 83 – medial lamellae of internal sac, ventral view; 84 – distal diverticula of everted internal sac, ventral view; 85 – everted internal sac, ventral view; 86 – spermatheca; 87 ­ 88 – details of internal sac retracted into median lobe, lateral view; 89 – copulatory piece of internal sac, lateral view; 90 – medial lamella of internal sac, lateral view; 91 – everted internal sac, lateral view; 92 – right distal diverticulum of everted internal sac, lateral view; 93 – apex of left paramere, side facing median lobe. Scale bar 0.2 mm (81, 85, 87 ­ 88, 91), 0.1 mm (82 ­ 84, 86, 89 ­ 90, 92 ­ 93).

FIGURES 57 ­ 60. 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).

FIGURES 8 ­ 17. Mouthparts of Geostiba circellaris (Gravenhorst) (8, Moscow Region, Russia), G. infirma (Weise) (9, Ivano­Frankovsk Region, Ukraine), G. carteriensis Pace (10 ­ 15, Tennessee), G. appalachigena Gusarov, sp. n. (16, paratype from West Virginia) and G. pluvigena Gusarov, sp. n. (17, paratype from North Carolina). 8 ­ 10, – prementum; 11 – hypopharynx; 12 – left maxilla, ventral view; 13 – left galea, dorsal view; 14 – left lacinia, dorsal view; 15 – mentum; 16 ­ 17 – right antenna. Scale bar 0.1 mm (8 ­ 15), 0.2 mm (16 ­ 17). L – Length of antennal article.