Atheta (Microdota) formicaensis Klimaszewski & Webster

Klimaszewski, Jan, Webster, Reginald P., Sikes, Derek, Bourdon, Caroline & Labrecque, Myriam, 2015, A review of Canadian and Alaskan species of the genera Clusiota Casey and AthetaThomson, subgenusMicrodota Mulsant & Rey (Coleoptera, Staphylinidae, Aleocharinae), ZooKeys 524, pp. 103-136: 115-116

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scientific name

Atheta (Microdota) formicaensis Klimaszewski & Webster

sp. n.

Taxon classification Animalia Coleoptera Staphylinidae

Atheta (Microdota) formicaensis Klimaszewski & Webster  sp. n. Figs 61-68

Holotype (male).

Canada, New Brunswick, York Co., New Maryland, Charters Settlement, 45.8395°N, 66.7391°W, 19.V.2006, R.P. Webster coll. // mixed forest, on surface of nest of black Formica  sp. (LFC) 1 male. Paratypes: labelled as holotype (RWC) 1 male, 1 female; Charters Settlement, 45.8395°N, 66.7391°W, 29.IV 2004, R.P. Webster coll. // mixed forest, on surface of nest of black Formica  sp. (RWC) 3 sex undetermined; same data except: 30.IV.2005 // mixed forest in nest of black Formica  sp., sifting nest material (RWC) 2 sex undetermined; Queens Co., Cranberry Lake P.N.A., 46.1125°N, 65.6075°W, 13.V.2011, R.P. Webster coll. // old red oak forest, in nest of black mound-building Formica  species, near surface of mound (LFC, RWC) 1 female, 2 sex undetermined.


The specific name formicaensis is a feminine adjective derived from the generic name Formica  , an ant genus found in association with the type series.


Body length 2.6-2.8 mm, subparallel, moderately convex, head and posterior part of abdomen dark brown, pronotum medium to dark brown, elytra with centre of disc yellowish brown and darker edges, base of abdomen light brown, legs yellowish brown (Fig. 61); integument glossy, sparsely punctate and sparsely pubescent, microsculpture distinct and stronger on pronotum and elytra; head slightly narrower than pronotum, rounded and slightly angular posteriorly, eyes small and shorter than postocular area dorsally; antennal articles V–X from subquadrate to slightly transverse; pronotum transverse, slightly narrower than elytra; elytra wider and as long as pronotum; abdomen subparallel. MALE. Tergite VIII truncate apically (Fig. 62); sternite VIII broadly rounded apically and slightly pointed medially (Fig. 63); median lobe of aedeagus narrowly oval in dorsal view with short and triangular tubus (Fig. 65), in lateral view tubus sinuate basally and then straight and rounded apically (Fig. 64); internal sac structures as illustrated (Figs 64, 65). FEMALE. Tergite VIII truncate apically (Fig. 66); sternite VIII broadly rounded apically (Fig. 67); spermatheca small, S-shaped, capsule spherical without apparent apical invagination, stem narrow and sinuate (Fig. 68).

Natural history.

Adults were found in association with nests of black ants in the genus Formica  in April and May.


Known only from NB, Canada.


This species is probably closely associated with nests of the ant genus Formica  . It is distinguished from all other Nearctic species of Microdota  by the shape of the median lobe of the aedeagus and spermatheca. The shape of the spermatheca is similar to that of Palaearctic Atheta (Microdota) glabricula  Thomson ( Palm 1970).