Seeversiella geostiboides Gusarov

Gusarov, Vladimir I., 2003, A revision of the genus Seeversiella Ashe, 1986 (Coleoptera: Staphylinidae: Aleocharinae), Zootaxa 142, pp. 1-102 : 86-89

25. Seeversiella geostiboides Gusarov , sp. n. ( Figs. 344­355 )

Type material. Holotype ,, COSTA RICA: Cartago: 2.0 km E Villa Mills, 9°34'00"N 83°41'50"W, 2750 m, oak forest litter (R.Anderson), 15.ii.1998 ( KSEM).

Paratypes: COSTA RICA: Cartago:, same data as the holotype ( KSEM).

Diagnosis. Seeversiella geostiboides can be distinguished from other species of Seeversiella by having uniformly brown body; small eyes (temples 3.5­4.0 times as long as eyes); pronotal pubescence in lateral portions of the disc directed posteriorly; elytra much shorter than pronotum; reduced wings (shorter than elytra); by lacking clear medial emargination at the posterior margin of male tergum 8 ( Fig. 344 ); tergum 8 with four pairs of macrosetae; by the distinct shape of aedeagus ( Figs. 348­354 ) and spermatheca ( Fig. 355 ).

Seeversiella geostiboides can be distinguished from S. impressicollis by not asperate pronotal punctation; in males pronotum without broad medial impression, lateral portions of posterior margin of tergum 3 extending as short and blunt projections (as in Fig. 19 ), and tergum 7 with medial carina; the apex of median lobe in parameral view more rounded ( Figs. 348­349 ; 311­312); and spermatheca with larger distal portion ( Figs. 355 ; 320).

Seeversiella geostiboides can be distinguished from S. sulcicollis by not asperate pronotal punctation; in males pronotum without medial furrow and posterior margin of tergum 8 without denticles; the apex of median lobe without divergent carinae (in parameral view) ( Figs. 348­349 ).

Seeversiella geostiboides differs from S. microphthalma and S. paramoana in having pubescence in the lateral portions of pronotum directed posteriorly; in narrower apex of median lobe (in parameral view) ( Figs. 348­349 ; 335­336; 377­378); and different shape of the distal portion of spermatheca ( Figs. 355 ; 341; 381).

Seeversiella geostiboides differs from S. flavida and S. adusta in having pubescence in the lateral portions of pronotum directed posteriorly; tergum 8 with four pairs of macrosetae; and different shape of the distal portion of spermatheca ( Figs. 355 ; 358; 371).

Description. Length 2.6 mm. Body uniformly brown.

Head surface glossy, with fine and weak isodiametric microsculpture, with fine and poorly visible punctation, distance between punctures equals 2 times their diameter. Temples 3.5­4.0 times as long as eyes. Antennal article 2 as long as 3, article 4 slightly transverse, 5­10 transverse (ratio 1.6­2.0).

Pronotum slightly transverse, 1.3 times as wide as head, width 0.47­0.50 mm, length 0.43­0.46 mm, width to length ratio 1.1, surface glossy, with fine isodiametric microsculpture, with fine punctation, distance between punctures equals 1­2 times their diameter. Pronotal pubescence in lateral portions of the disc directed posteriorly. Elytra wider and much shorter (measured from humeral angle) than pronotum (pronotal length to elytral length ratio 1.4), 1.8 times wider than long, glossy, with poorly visible microsculpture, with fine and asperate punctation, distance between punctures equals 1­2 times their diameter, punctures stronger than on pronotum. Wings reduced to short vestiges, shorter than elytra.

Abdominal terga glossy, terga 3­5 with microsculpture consisting of transverse meshes, and with fine punctation, distance between punctures equals 2­3 times their diameter; tergum 7 with microsculpture consisting of isodiametric or transverse meshes and with fine and sparse punctation, distance between punctures equals 3­7 times. Apical margin of tergum 7 without white palisade fringe. Tergum 8 with four pairs of macrosetae ( Figs. 344, 346 ).

In the only known male the posterior angles of tergum 3 not projecting as spines, lateral portions of posterior margin slightly extending as short and blunt projections (as in Fig. 19 ); tergum 7 in front of posterior margin with medial carina 2/3 as long as the tergum; posterior margin of tergum 8 without clear medial emargination ( Fig. 344 ).

Aedeagus as in Figs. 348­354 . Apex of paramere narrow, proximal seta approximately as long as the other three setae ( Fig. 352 ).

Spermatheca as in Fig. 355 .

Distribution. Known from Cerro de la Muerte, Costa Rica ( Fig. 389 ).

Natural History. Seeversiella geostiboides was collected in forest litter at altitude of 2750 m.

Figures

FIGURE 389. Geographical distribution of eleven species of Seeversiella (with very short elytra) in the high mountains of Costa Rica. Isohypses 1000 m, 2000 m and 3000 m are shown. Areas above 2000 m are grey and those above 3000 m are solid black.

FIGURES 344 ­ 347. Abdominal segment 8 of Seeversiella geostiboides Gusarov, sp. n. (344 ­ 345, holotype; 346 ­ 347, paratype from Villa Mills, Costa Rica). 344 – male tergum 8; 345 – male sternum 8; 346 – female tergum 8; 347 – female sternum 8. Scale bar 0.2 mm.

FIGURES 348 ­ 355. Genitalia of Seeversiella geostiboides Gusarov, sp. n. (348 ­ 354, holotype; 355, paratype from Villa Mills, Costa Rica). 348 – median lobe, parameral view; 349 – apex of median lobe, parameral view; 350 – median lobe, lateral view; 351 – apex of median lobe, lateral view; 352 – apex of left paramere; 353 – details of internal sac retracted into median lobe, abparameral view; 354 – details of internal sac retracted into median lobe, lateral view; 355 ­ spermatheca. Scale bar 0.2 mm (348, 350, 353 ­ 354), 0.1 mm (349, 351 ­ 352, 355).

FIGURES 17 ­ 19. Body outline of Seeversiella globicollis (Bernhauer) (17, Volcán Tacana, Mexico), S. micralymma Gusarov, sp. n. (18, paratype from Cerro de la Muerte, Costa Rica) and S. flavida Gusarov, sp. n. (19, paratype from Cerro de la Muerte, Costa Rica). Scale bar 1 mm.