Stethusa

Gusarov, Vladimir I., 2003, A revision of the Nearctic species of the genus Stethusa Casey, 1910 (Coleoptera: Staphylinidae: Aleocharinae), Zootaxa 239, pp. 1-43 : 12

Key to Nearctic species of Stethusa

1 Antennal article 11 with two subbasal impressions densely covered with microsetae ( Figs. 15­16 ). Internal sac of aedeagus with two strong distal spines ( Figs. 34­35, 37­ 38 ). Female with accessory sclerite ( Fig. 40 ). Distal end of spermatheca bent towards spermathecal gland ( Figs. 41­42 ). Body length 2.0­3.0 mm, pronotal length 0.41­0.53 mm. Widely distributed in the eastern United States ( Fig. 110 ). Also known from Bolivia, Paraguay, the Galápagos Islands and the Antilles..1. S. dichroa (Gravenhorst)

– Antennal article 11 without subbasal impressions, microsetae evenly distributed. Internal sac of aedeagus without strong distal spines ( Figs. 53­54 , 67­68 ). Female without accessory sclerite. Distal end of spermatheca bent away from spermathecal gland ( Figs. 57 , 70 ) ....................................................................................................... 2

2 Body larger, length 3.2­3.5 mm, pronotal length 0.54­0.61 mm. Apex of median lobe in lateral view straight ( Figs. 50­51 ). Spermatheca longer ( Fig. 57 ). Known from Louisiana, Mississippi and southern Indiana ( Fig. 111 )........ 2. S. klimschi (Bernhauer)

– Body smaller, length 2.1­2.5 mm, pronotal length 0.36­0.44 mm. Apex of median lobe in lateral view bent paramerally ( Figs. 65­66 ). Spermatheca shorter ( Fig. 70 ). Widely distributed in the eastern United States ( Fig. 111 ).......... 3. S. spuriella (Casey)

Figures

FIGURE 110. Geographical distribution of Stethusa dichroa (Gravenhorst) in North America. The exact localities in Vermont and Maine are unknown.

FIGURE 111. Geographical distribution of Stethusa klimschi (Bernhauer) and S. spuriella (Casey). The exact locality in Ohio is unknown.

FIGURES 14 ­ 17. Details of Stethusa dichroa (Gravenhorst) (male (14 ­ 16) and female (17), Eddyville, Illinois). 14 – right mesotibia; 15 – antennal article 11; 16 – right antenna; 17 – right metatarsus. Scale bar 0.1 mm (15, 17), 0.2 mm (14), 0.4 mm (16).

FIGURES 34 ­ 39. Aedeagus of Stethusa dichroa (Gravenhorst) (males, 12 km NNE Lawrence, Kansas (35 ­ 36, 38 ­ 39); 18 km SSE Lawrence (34, 37 )). 34 – everted internal sac, parameral view; 35 ­ 36 – details of retracted internal sac, abparameral view; 37 – everted internal sac, lateral view; 38 ­ 39 – details of retracted internal sac, lateral view. SB ­ sclerotized band. Scale bar 0.2 mm.

FIGURES 40 ­ 42. Details of Stethusa dichroa (Gravenhorst) (female, 12 km NNE Lawrence, Kansas). 40 – female abdominal segments 9 ­ 10, ventral view; 41 ­ 42 – spermatheca of the same specimen illustrated at different angles. The arrow indicates the point where the spermathecal gland is attached. Scale bar 0.2 mm (40), 0.1 mm (41 ­ 42).

FIGURES 53 ­ 57. Aedeagus and spermatheca of Stethusa klimschi (Bernhauer) (lectotype (53 ­ 54); male (55 ­ 56) and female (57) from Vicksburg, Mississippi). 53 – details of retracted internal sac, abparameral view; 54 – details of retracted internal sac, lateral view; 55 – copulatory piece, lateral view; 56 – copulatory piece, abparameral view; 57 – spermatheca. Scale bar 0.2 mm (53 ­ 54), 0.1 mm (55 ­ 57).

FIGURES 63 ­ 70. Aedeagus and spermatheca of Stethusa spuriella (Casey) (male, 18 km SSE Lawrence, Kansas (63 ­ 69); and female 9 km W Buffalo Gap, Virginia (70 )). 63 – median lobe, parameral view; 64 – apex of median lobe, parameral view; 65 – median lobe, lateral view; 66 – apex of median lobe, lateral view; 67 – details of retracted internal sac, abparameral view; 68 – details of retracted internal sac, lateral view; 69 – apex of left paramere; 70 – spermatheca. Scale bar 0.1 mm (64, 66, 69 ­ 70), 0.2 mm (63, 65, 67 ­ 68).

FIGURES 48 ­ 52. Aedeagus of Stethusa klimschi (Bernhauer) (lectotype (48 ­ 51); and male from Vicksburg, Mississippi (52 )). 48 – median lobe, parameral view; 49 – apex of median lobe, parameral view; 50 – median lobe, lateral view; 51 – apex of median lobe, lateral view; 52 – apex of left paramere. Scale bar 0.1 mm (49, 51 ­ 52), 0.2 mm (48, 50).