Seeversiella impressicollis Gusarov

Gusarov, Vladimir I., 2003, A revision of the genus Seeversiella Ashe, 1986 (Coleoptera: Staphylinidae: Aleocharinae), Zootaxa 142, pp. 1-102 : 77-79

22. Seeversiella impressicollis Gusarov , sp. n. ( Figs. 307­320 )

Type material. Holotype ,, COSTA RICA: Cartago: Cerro Chirripó, Valle de los Conelos, 9°28'37"N 83°29'23"W, 3600 m, paramo shrub litter (R.Anderson), 26.vi.1999 ( KSEM).

Paratypes: COSTA RICA: Cartago: 14 specimens, same data as the holotype ( KSEM).

Diagnosis. Seeversiella impressicollis can be distinguished from other species of Seeversiella by having brown or dark brown body with lighter pronotum and elytra; temples 1.8­2.2 times as long as eyes; elytra much shorter than pronotum; reduced wings (shorter than elytra); by lacking the medial emargination at the posterior margin of male tergum 7 ( Fig. 307 ); tergum 8 with four pairs of macrosetae; by the distinct shape of aedeagus ( Figs. 311­319 ) and spermatheca ( Fig. 320 ).

Seeversiella impressicollis differs from S. sulcicollis in having smaller body; in males pronotum with broad medial impression, posterior margin of tergum 3 not projecting, tergum 7 without medial carina and posterior margin of tergum 8 without medial denticles ( Fig. 307 ); apex of median lobe in parameral view without carinae ( Figs. 311­312 ); copulatory piece of internal sac shorter ( Figs. 317 ; 326, 328); sclerites of lateral diverticula of internal sac more slender ( Figs. 318 ; 326).

CP – copulatory piece; ML – medial lamellae; SLD – sclerite of lateral diverticulum of internal sac.

Seeversiella impressicollis differs from S. microphthalma in having pronotum with more asperate punctation; in males pronotum with broad medial impression, posterior angles of tergum 3 not projecting as spines; lateral diverticula of internal sac with long spiniform sclerites ( Figs. 316, 318 ; 343); spermatheca with smaller distal portion ( Figs. 320 ; 341).

Description. Length 2.2­2.7 mm. Body brown or dark brown with lighter pronotum and elytra; legs brownish yellow.

Head surface glossy, with fine and weak isodiametric microsculpture, with fine and poorly visible punctation, distance between punctures equals 2 times their diameter. Temples 1.8­2.2 times as long as eyes. Antennal article 2 longer than 3, article 4 subquadrate, 5­10 transverse (ratio 1.5­1.8).

Pronotum slightly transverse, 1.2 times as wide as head, width 0.47­0.53 mm, length 0.43­0.49 mm, width to length ratio 1.1, surface glossy, with fine isodiametric microsculpture, with fine and slightly asperate punctation, distance between punctures equals 1­2 times their diameter. Elytra wider and much shorter (measured from humeral angle) than pronotum (pronotal length to elytral length ratio 1.5), 1.8 times wider than long, glossy, with fine and weak isodiametric microsculpture, with fine and asperate punctation, distance between punctures equals 1­2 times their diameter. Wings reduced to short vestiges, shorter than elytra.

Abdominal terga glossy, with fine microsculpture consisting of transverse meshes, with fine punctation, distance between punctures equals 1­4 times their diameter on terga 3­5 and 3­5 times on tergum 7. Apical margin of tergum 7 without white palisade fringe. Tergum 8 with four pairs of macrosetae ( Figs. 307, 309 ).

In males pronotum with wide medial impression; posterior angles of tergum 3 not projecting; tergum 7 without medial carina or tubercle; posterior margin of tergum 8 without emargination ( Fig. 307 ).

Aedeagus as in Figs. 311­319 . Apex of paramere narrow, proximal seta approximately as long as the other three setae ( Fig. 313 ).

Spermatheca as in Fig. 320 .

Distribution. Known from Cerro Chirripó, Costa Rica ( Fig. 389 ).

Natural History. Seeversiella impressicollis was collected in paramo shrub litter at altitude of 3600 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 307 ­ 310. Abdominal segment 8 of Seeversiella impressicollis Gusarov, sp. n. (paratypes from Cerro Chirripó, Costa Rica). 307 – male tergum 8; 308 – male sternum 8; 309 – female tergum 8; 310 – female sternum 8. Scale bar 0.2 mm.

FIGURES 311 ­ 320. Genitalia of Seeversiella impressicollis Gusarov, sp. n. (paratypes from Cerro Chirripó, Costa Rica). 311 – median lobe, parameral view; 312 – apex of median lobe, parameral view; 313 – apex of left paramere; 314 – median lobe, lateral view; 315 – apex of median lobe, lateral view; 316 – details of internal sac retracted into median lobe, lateral view; 317 – copulatory piece, lateral view; 318 – everted internal sac, parameral view; 319 – medial lamellae, parameral view; 320 ­ spermatheca. Scale bar 0.2 mm (311, 314, 316, 318), 0.1 mm (312 ­ 313, 315, 317, 319 ­ 320).