Seeversiella curtipennis Gusarov

Gusarov, Vladimir I., 2003, A revision of the genus Seeversiella Ashe, 1986 (Coleoptera: Staphylinidae: Aleocharinae), Zootaxa 142, pp. 1-102 : 64-68

18. Seeversiella curtipennis Gusarov , sp. n. ( Figs. 247­264 )

Type material. Holotype ,, COSTA RICA: Cartago: P. N. Volcán Irazú, 9°58'30"N 83°51'30"W, 3300 m, berlese forest litter (R.Anderson), 18.vi.1997 ( KSEM).

Paratypes: COSTA RICA: Cartago: 28 specimens, same data as the holotype; San Jose: 4 specimens, Estación Cuerici, 4.6 km E Villa Mills, 9°34'00"N 83°40'00"W, 2600 m, berlese forest litter (R.Anderson), 26.vi.1997 (all – KSEM).

Diagnosis. Seeversiella curtipennis can be distinguished from other species of Seeversiella by having brown body; temples 1.9­2.0 times as long as eyes; elytra shorter than pronotum; reduced wings (shorter than elytra); by lacking the medial emargination at the posterior margin of the male tergum 7 ( Fig. 247 ); tergum 8 with three pairs of macrosetae; by the distinct shape of aedeagus ( Figs. 251­254 , 256­264 ) and spermatheca ( Fig. 255 ).

Seeversiella curtipennis differs from S. scabricollis , S. furcativentris and S. brunnea in having shorter elytra (shorter than pronotum); reduced wings (shorter than elytra); posterior margin of male tergum 8 without medial emargination ( Fig. 247 ); broad apex of the median lobe (in parameral view) ( Figs. 251­252 ; 194­196; 212­213; 239­240); long medial lamellae of the internal sac ( Figs. 258­259 ; 201) protruding apically when the internal sac is retracted ( Figs. 256­257 ); lateral diverticula without sclerotized denticles ( Figs. 259 ; 200); and longer spermatheca ( Figs. 255 ; 205).

Seeversiella curtipennis differs from S. lativentris in having weaker basal constriction of the apex of median lobe (in parameral view) ( Figs. 251­252 ; 269­270).

Description. Length 2.6­3.1 mm. Body brown.

Head surface matte, with fine isodiametric microsculpture, fine and slightly asperate punctation, distance between punctures equals 1­2 times their diameter. Temples 1.9­2.0 times as long as eyes. Antennal article 2 as long as 3, article 4 slightly transverse, 5­10 transverse (ratio 1.5­2.0).

Pronotum slightly transverse, 1.2 times as wide as head, width 0.50­0.56 mm, length 0.46­0.50 mm, width to length ratio 1.1, surface matte, with fine isodiametric microsculpture; punctation fine and weak, distance between punctures equals 1­2 times their diameter. Elytra wider and shorter (measured from humeral angle) than pronotum (pronotal length to elytral length ratio 1.2), 1.7 times wider than long, glossy, with fine and weak isodiametric microsculpture, and fine and slightly 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 2­4 times their diameter on terga 3­5 and 4­7 times on tergum 7. Apical margin of tergum 7 without white palisade fringe. Tergum 8 with three pairs of macrosetae ( Figs. 247, 249 ).

In large males posterior angles of tergum 3 projecting as spines up to ½ as long as tergum 3 (measured medially); tergum 7 with medial carina along midline, the carina up to 2/3 as long as tergum length; posterior margin of tergum 8 without emargination ( Fig. 247 ).

Aedeagus as in Figs. 251­254 , 256­264 . Apex of paramere narrow, proximal seta approximately as long as the other three setae ( Fig. 260 ).

Spermatheca as in Fig. 255 .

Discussion. Volcán Irazú and Cerro Cuerici, the localities where S. curtipennis was found, are separated by the distance of 50 km and the gap as low as 1400 m. Considering the distribution of the other species of Seeversiella in Costa Rica, and the fact that in S. curtipennis the wings are reduced to vestiges that are shorter than elytra, it is clear that the two known populations of this species are isolated from each other. Despite this, both are identical in the structure of genitalia, including the internal sac. Apparently, the isolation of the two population is recent and has not allowed enough time for their divergence.

LD – lateral diverticulum of internal sac; ML – medial lamellae.

Distribution. Known from Volcán Irazú and Cerro Cuerici, Costa Rica ( Fig. 388 ). Natural History. Seeversiella curtipennis was collected in forest litter at altitude of 2600­3300 m.

Figures

FIGURE 388. Geographical distribution of Scabricollis group in Costa Rica and Panama. 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 247 ­ 250. Abdominal segment 8 of Seeversiella curtipennis Gusarov, sp. n. (paratypes, Volcán Irazú, Costa Rica). 247 – male tergum 8; 248 – male sternum 8; 249 – female tergum 8; 250 – female sternum 8. Scale bar 0.4 mm.

FIGURES 251 ­ 255. Genitalia of Seeversiella curtipennis Gusarov, sp. n. (paratypes, Volcán Irazú, Costa Rica). 251 – median lobe, parameral view; 252 – apex of median lobe, parameral view; 253 – median lobe, lateral view; 254 – apex of median lobe, lateral view; 255 ­ spermatheca. Scale bar 0.2 mm (251, 253), 0.1 mm (252, 254 ­ 255).

FIGURES 256 ­ 264. Aedeagus of Seeversiella curtipennis Gusarov, sp. n. (paratypes, Volcán Irazú, Costa Rica). 256 – details of internal sac retracted into median lobe, abparameral view; 257 – details of internal sac retracted into median lobe, parameral view; 258 – medial lamellae, parameral view; 259 – everted internal sac, parameral view; 260 – apex of left paramere; 261 ­ 262 – details of internal sac retracted into median lobe, lateral view; 263 – right distal sclerite of internal sac; 264 – everted internal sac, lateral view. Scale bar 0.2 mm (256 ­ 257, 259, 261 ­ 262, 264), 0.1 mm (258, 260, 263).