Tachyusa gemma Casey, 1906

Pa ṡnik, Grzegorz, 2006, A revision of the World species of the genus Tachyusa Erichson, 1837 (Coleoptera, Staphylinidae: Aleocharinae), Zootaxa 1146, pp. 1-152 : 54-55

Tachyusa gemma Casey, 1906 ( Figs. 36–38)

Tachyusa gemma Casey, 1906: 213 .

Tachyusa (Caliusa) gemma: Fenyes, 1920: 173 ; Bernhauer & Scheerpeltz, 1926: 586.

Type material. Lectotype (here designated): ♀: South Africa, Wellington , type USNM 38960 ( USNM) ; Paralectotypes: ♂ and ♀: same data as the lectotype ( USNM) .

Additional material. Angola: 5 mls. NE Negola , 25.III.1972, 2 exx ( BMNH) . Namibia: Kunene, Epupa Falls, Kunene River banks, 20–21.II.1994, Uhlig, 4 exx ( ZMHB) ; 1 ex ( ISEA). Republic of South Africa: Cape Province, Karoo National Park , 13.XI.1993, Uhlig, 1 ex ( ZMHB) ; Cape Province, 15 miles W Avontuur, S Uniondale, 28.II.1951, Swedish South Africa Expedition 1950–1951, Brinck­Rudebeck, 1 ex ( MZLU) ; Damarad, Ugab River , 21.08ºS 14.58ºE, 24.XII.1974, Endrödy­Younga, 1 ex ( TMSA) ; Kapland, Williams­Town Distr. , „ Tachyusa pallidula Bernh. Cotyp [ms name]”, 1 ex ( FMNH) ; Kruger National Park, Skukuza camp, 24.59ºS 31.35ºE, 3.III.1996, Endrödy­Younga, 1 ex ( TMSA) ; Little Karroo, Raubenheimer dam E, 23.25ºS 22.19ºE, 21.X.1993, Endrödy­Younga, 1 ex ( TMSA) ; Little Karroo, Baviaanskloof , 33.37ºS 24.15ºE, 28.X.1993, Endrödy­Younga, 1 ex ( TMSA) ; 1 ex ( ISEA); Natal, Itala Game Reserve, Thalu river banks, 27.I.1994, Uhlig, 12 exx ( ZMHB) ; 2 exx ( ISEA); Natal: Mkuze National Park , 2–3.II.1984, Uhlig, 1 ex ( ISEA) ; Natal, Karkloof Forest , 1300 m, 29.18ºS 30.13ºE, 11.XII.1989, Endrödy­Younga & Klimaszewski, 1 ex ( TMSA) ; Okahandja , 19–29.III.1928, R. E. Turner, 1 ex ( BMNH) ; Transvaal, Pretoria , 28– 30.XII.1977, Endrödy­Younga, 1 ex ( HNHM) ; Cape Province (localities not specified), 2 exx ( IRSNB) ; 2 exx ( FMNH); Natal (localities not specified), 1 ex ( IRSNB). Zimbabwe: Kyle Park at Lake Mutirikwi , 1–5.XII.1993, Uhlig, 1 ex ( ZMHB) .

Redescription. Body. Length 2.6–2.8 mm, convex, parallel­sided, glossy; head pitchy brown, pronotum reddish brown to brown, elytra reddish brown, abdomen black with two basal tergites red to reddish brown, legs testaceous, antennae brown with antennomeres 1– 3 red.

Head circular in outline, convex, eyes large, moderately protruding from lateral contours of head, length of each seen from above subequal to that of postocular region; surface of head without microsculpture; puncturation fine and relatively sparse. Antennae long, clearly increasing in width apically, antennomeres 2 and 3 subequal in length, antennomeres 4–6 longer than wide, antennomeres 7–10 quadrate, antennomere 11 nearly conical.

Pronotum quadrate, lateral sides clearly concavely narrowed to obtuse hind angles; before base with small and shallow transverse impression; surface without microsculpture; puncturation relatively coarse, moderately dense and asperate; pubescence at midline directed posteriorly.

Elytra longer than wide, at suture as long as pronotal length at midline; surface lacking microsculpture; puncturation fine, moderately dense and weakly asperate.

Abdomen parallel­sided, bases of tergites 3–5 each with deep transverse impression, impressions with 7–8 longitudinal ridges connected by the short transverse ridges in the shape of honeycomb, tergal puncturation very fine and scattered, punctures very small and scarcely visible, surface without microsculpture.

Male. Aedeagus as in Figs. 36–37. Female. Spermatheca as in Fig. 38.

Remarks. Tachyusa gemma is very similar to T. leptothorax , from which it can be distinguished by its larger size, the longer elytra, the more convex pronotum, the sparser pronotal puncturation and by the shape of the genitalia.

Distribution. Tachyusa gemma is common in southern Africa ( Angola, Namibia, Republic of South Africa and Zimbabwe).