Seeversiella micralymma Gusarov

Gusarov, Vladimir I., 2003, A revision of the genus Seeversiella Ashe, 1986 (Coleoptera: Staphylinidae: Aleocharinae), Zootaxa 142, pp. 1-102 : 73-76

21. Seeversiella micralymma Gusarov , sp. n. ( Figs. 12, 14, 16 , 18 , 291 ­306)

Type material. Holotype ,, COSTA RICA: San Jose/Cartago: Cerro Buenavista, km 89 Int. Amer. Hwy., 9°33'00"N 83°45'30"W, 3200 m, leaf litter (R.Anderson), 18.vi.1998 ( KSEM).

Paratypes: COSTA RICA: San Jose/Cartago: 22, 28, same data as the holotype;, 2, ditto but 3300 m, 8.vi.1997; Cartago: 6, 10, Cerro Buenavista, 9°33'02"N [the latitude on the label (9°43'02"N) is incorrect] 83°45'14"W, 3300 m, subparano litter (R.Anderson), 15.ii.1998; 16, 19, Cerro de la Muerte, Pan American Highway, km 89, 3300 m, elfin bamboo forest litter (R.Anderson), 10.ii.1996 (all ­ KSEM).

Diagnosis. Seeversiella micralymma can be distinguished from other species of Seeversiella by having dark brown body with lighter pronotum and elytra; temples 1.1­1.9 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 the male tergum 7 ( Fig. 291 ); tergum 8 with four pairs of macrosetae; by the distinct shape of aedeagus ( Figs. 295­305 ) and spermatheca ( Fig. 306 ).

Seeversiella micralymma differs from S. curtipennis and S. lativentris in having glossy pronotum with weak microsculpture; tergum 8 with four pairs of macrosetae; medial lamellae of internal sac short ( Fig. 305 ), the apices of lamellae not protruding from retracted sac ( Fig. 295 ); the apex of median lobe in parameral view narrow ( Figs. 295­ 296 ); and J­shaped spermatheca without umbilicus ( Fig. 306 ).

Seeversiella micralymma differs from S. luridicollis in having narrower apex of median lobe (in parameral view) ( Figs. 295­296 ; 282­283) and J­shaped spermatheca without umbilicus ( Fig. 306 ).

Description. Length 2.1­2.5 mm. Body dark brown, pronotum and elytra brown to yellowish brown, antennae, mouthparts and legs dark brown.

Head surface glossy, with fine and weak isodiametric microsculpture, with fine punctation, distance between punctures equals 2­3 times their diameter. Temples 1.1­1.9 times as long as eyes. Antennal article 2 as long as 3, article 4 elongate, 5 subquadrate, 6­10 slightly transverse.

Pronotum slightly transverse, 1.1 times as wide as head, width 0.39­0.41 mm, length 0.34­0.40 mm, width to length ratio 1.1, surface glossy, microsculpture and punctation as on head disc. 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 fine and weak isodiametric microsculpture, with fine and slightly asperate punctation, distance between punctures equals 3­4 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 3­5 times on tergum 7. Apical margin of tergum 7 without white palisade fringe. Tergum 8 with four pairs of macrosetae ( Figs. 291, 293 ).

In males posterior angles of tergum 3 not projecting as spines; lateral portions of posterior margin convex, extending posteriorly beyond the level of the medial portion of the margin ( Figs. 16 , 18 ); tergum 7 in front of posterior margin with medial carina up to half as long as tergum; posterior margin of tergum 8 without emargination ( Fig. 291 ).

Aedeagus as in Figs. 295­305 . Apex of paramere narrow, proximal seta approximately as long as the other three setae ( Fig. 302 ).

Spermatheca as in Fig. 306 .

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

Natural History. Seeversiella micralymma was collected in leaf litter at altitude of 3200­3300 m.

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

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 10 ­ 16. Details of Seeversiella globicollis (Bernhauer) (10, Anticosti, Quebec; 13, Waterton Lakes National Park, Alberta), S. scabricollis Gusarov, sp. n. (11, 15, paratype from Volcán Barva, Costa Rica) and S. micralymma Gusarov, sp. n. (12, 14, 16, paratype from Cerro Buenavista, Costa Rica). 10 ­ 12 – pronotum; 13 ­ 14 – mesometathorax; 15 – male tergum 3 and paratergites; 16 – male tergum 3. Scale bar 0.4 mm (10 ­ 11, 15), 0.3 mm (12 ­ 13, 16), 0.2 mm (14).

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.

FIGURES 291 ­ 294. Abdominal segment 8 of Seeversiella micralymma Gusarov, sp. n. (paratypes from Cerro de la Muerte (291 ­ 292) and Cerro Buenavista (293 ­ 294), Costa Rica). 291 – male tergum 8; 292 – male sternum 8; 293 – female tergum 8; 294 – female sternum 8. Scale bar 0.2 mm.

FIGURES 295 ­ 298. Aedeagus of Seeversiella micralymma Gusarov, sp. n. (paratype from Cerro de la Muerte, Costa Rica). 295 – median lobe, parameral view; 296 – apex of median lobe, parameral view; 297 – median lobe, lateral view; 298 – apex of median lobe, lateral view. Scale bar 0.2 mm (295, 297), 0.1 mm (296, 298).

FIGURES 299 ­ 306. Genitalia of Seeversiella micralymma Gusarov, sp. n. (paratypes from Cerro de la Muerte (299, 301 ­ 305) and Cerro Buenavista (300, 306), Costa Rica). 299 – details of internal sac retracted into median lobe, lateral view; 300 – copulatory piece, lateral view; 301 – everted internal sac, lateral view; 302 – apex of left paramere; 303 – details of internal sac retracted into median lobe, abparameral view; 304 – everted internal sac, parameral view; 305 – medial lamellae, parameral view; 306 ­ spermatheca. Scale bar 0.2 mm (299, 301, 303 ­ 304), 0.1 mm (300, 302, 305 ­ 306).