Geostiba

Gusarov, Vladimir I., 2002, A revision of Nearctic species of the genus Geostiba Thomson, 1858 (Coleoptera: Staphylinidae: Aleocharinae), Zootaxa 81, pp. 1-88: 75-76

publication ID

http://doi.org/ 10.5281/zenodo.155701

publication LSID

lsid:zoobank.org:pub:B36587A1-248A-4194-8424-46C9BBA15606

persistent identifier

http://treatment.plazi.org/id/5B50E916-FFD4-396F-4D2D-FA7AFBABFE84

treatment provided by

Plazi

scientific name

Geostiba
status

 

15. Geostiba  (s. str.) circellaris ( Gravenhorst, 1806)  ( Figs. 21­23View FIGURES 21 ­ 25; Figs. 1­4View FIGURES 1 ­ 7 in Assing (2001 ))

Aleochara circellaris Gravenhorst, 1806: 155  .

Geostiba  (s. str.) circellaris  : Benick & Lohse 1974: 112. Geostiba circellaris: Muona 1984: 229  .

Geostiba  (s. str.) circellaris: Assing 2001: 139  .

Material. CANADA: Newfoundland: ,, S Newfoundland, Rencontre West [47.61 °N 56.69 °W] (Lindroth), 16.vi. 1949 ( MZHF).

Diagnosis. Geostiba circellaris  can be distinguished from other Nearctic species of Geostiba  by having large eyes (temple length to eye length ratio 1.6­1.9), pronotal pubescence of type VI, reduced wings, elytra shorter than pronotum (pronotum length to elytron length ratio 1.1), the presence of one medial carina on male abdominal tergum 7 in front of posterior margin, the shape of the aedeagus and spermatheca ( Figs. 1­4View FIGURES 1 ­ 7 in Assing (2001), Figs. 21­23View FIGURES 21 ­ 25).

In North America there is no native species closely related to G. circellaris  . Geostiba circellaris  is superficially similar to G. impressula  in having pronotal pubescence of type VI but can be distinguished from the latter species by having tergum 7 with one medial carina in males and a different shape of spermatheca in females ( Fig. 4View FIGURES 1 ­ 7 in Assing (2001), Figs. 316­317View FIGURES 316 ­ 320).

Description. Length 2.3­2.8 mm. Body reddish brown to brownish black, in some specimens pronotum, elytra and abdominal segments 7­8 lighter, antennae reddish brown to dark brown, legs and mouthparts from brownish yellow to brown. Body parallel­sided.

Head as wide as long, surface on disk with fine isodiametric microsculpture, puncturation very fine, distance between punctures equal to 2­4 times their diameter. Temple length to eye length ratio 1.6­1.9. Antennal article 2 longer than article 3, article 4 subquadrate, articles 5­10 transverse, last article longer than 9 and 10 combined.

Pronotum as wide as long, width 0.43­0.53 mm, wider than head (pronotal width to head width ratio 1.2); surface on disk with fine isodiametric microsculpture, and fine puncturation, distance between punctures equal to 1­2 times their diameter; pronotal pubescence of type VI. Elytra measured from humeral angle shorter than pronotum (pronotal length to elytral length ratio 1.1), wider than long (1.4), with fine isodiametric microsculpture and fine asperate puncturation, punctures stronger than on pronotum, distance between punctures equals 1­2 times their diameter.

Abdominal terga with fine transverse microsculpture, with fine puncturation, puncturation becoming finer towards abdomen apex, on terga 3­5 distance between punctures equals 2­4 times their diameter. Tergum 7 with white edge.

In males pronotum with small medial tubercle at posterior margin (some females have very weak tubercle) and medial impression in front, each elytron with a tubercle near scutellum but distant from elytral suture. Male tergum 7 with one short medial carina in front of posterior margin. Male tergum 8 with two weak and short parallel carina in front of middle of convex posterior margin. Male sternum 8 with posterior margin convex, extending posteriorly beyond tergum.

Aedeagus as in Figs. 1­3View FIGURES 1 ­ 7 in Assing (2001). Internal sac of aedeagus with one pair of large diverticula ( Figs. 21­22View FIGURES 21 ­ 25).

Posterior margin of female tergum 8 convex. Posterior margin of female sternum 8 distinctly convex, without emargination.

Spermatheca as in Fig. 4View FIGURES 1 ­ 7 in Assing (2001).

Distribution. Geostiba circellaris  is a widespread Palaearctic species. In the Nearctic region, it is known only from Newfoundland ( Muona 1984), where it was introduced from Europe. Contrary to the opinion expressed by Lohse and Smetana (1988) Geostiba impressula ( Casey, 1906)  is not a synonym of G. circellaris  (see discussion for G. impressula  ). Geostiba circellaris  is not known from western North America.

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Coleoptera

Family

Staphylinidae

Loc

Geostiba

Gusarov, Vladimir I. 2002
2002
Loc

Geostiba

Muona 1984: 229
Benick 1974: 112
1974
Loc

Aleochara circellaris

Gravenhorst 1806: 155
Loc

Geostiba

Assing 2001: 139