Atheta richardsoni Klimaszewski & Larson

Klimaszewski, Jan, Larson, David J., Labrecque, Myriam & Bourdon, Caroline, 2016, Twelve new species and fifty-three new provincial distribution records of Aleocharinae rove beetles of Saskatchewan, Canada (Coleoptera, Staphylinidae), ZooKeys 610, pp. 45-112 : 62-64

Taxon classification Animalia Coleoptera Staphylinidae

Atheta richardsoni Klimaszewski & Larson sp. n. Figs 33-40

Holotype (male).

Canada, Saskatchewan, Hwy 21, 20 km N Maple Creek, 25-VI-2010, Gramma-stipa pasture, Richardson ground squirrel burrow, D. Larson (LFC). Paratype. Canada, Saskatchewan, Grassland National Park, W Block Larson’s Prairie Dog colony, 11-VI-2009, D. Larson (LFC) 1 female.

Etymology.

This species name is derived from the surname of Sir John Richardson, the surgeon-naturalist who participated in 19th century British naval expeditions to the arctic coast of "British North America", now Canada. In 1820 he discovered a new species of ground squirrel along the Saskatchewan River, which was later named after him as Urocitellus richardsonii . The holotype of Atheta richardsoni was found in a Richardson’s ground squirrel burrow.

Diagnosis.

Body narrowly subparallel (Fig. 33), length 1.9 mm, dark brown, with appendages yellowish-brown; head, pronotum and elytra finely and densely punctate and pubescent, punctures small, all pubescence directed straight or obliquely posteriad; integument moderately glossy, more so on abdomen (Fig. 33); pronotum transverse, narrower than elytra, with pubescence directed straight posteriad on median line of disc (Fig. 33); elytra at suture about as long as pronotum (Fig. 33); abdomen subparallel. MALE. Tergite VIII truncate apically (Fig. 36); sternite VIII broadly rounded apically (Fig. 37). Median lobe of aedeagus with large oval bulbus and broad tubus rapidly tapering near apex in dorsal view (Fig. 35), in lateral view tubus straight and narrowly rounded at apex, strongly produced ventrally (Fig. 34); internal sac structures as illustrated (Figs 34, 35). FEMALE. Tergite VIII transverse and truncate apically (Fig. 38); sternite VIII broadly arcuate apically, antecostal suture strongly sinuate (Fig. 39); spermatheca with narrowly pitcher-shaped capsule and thin stem ending with enlarged, sac-like posterior part (Fig. 40).

Distinguished from all other species of Nearctic Atheta by its small size, densely and finally punctate and pubescent forebody, nearly all pronotal pubescence directed straight posteriad (Fig. 33), the shape of median lobe of aedeagus with very broad tubus of median lobe in dorsal view (Fig. 35), and the shape of spermatheca with enlarged, sac-shaped posterior part of stem (Fig. 40).

Distribution.

Adults are known from SK.

Natural history.

The single male from SK was captured in a ground squirrel burrow, and the single female was found in a Prairie Dog colony in June.

Comments.

This species in body size and general appearance is similar to species of the subgenus Microdota of Atheta . However, it has a different pubescence pattern of pronotum with microsetae along midline of disc directed straight posteriad and elsewhere straight or obliquely posteriad (Fig. 33), and pubescence on elytra with microsetae directed approximately straight posteriad (Fig. 33). The tubus of the median lobe of the aedeagus is very broad and abruptly narrowed apically in dorsal view (Fig. 34), and spermatheca has enlarged and sac-shaped posterior part of stem (Fig. 40). These are unique features of this species, which slightly resemble those of European Atheta liturata Stephens, which has a similarly shaped median lobe of aedeagus and spermatheca, but the European species has a differently shaped male tergite VIII with strong lateral projections (for illustrations, see Palm 1970). The European species is known from mushrooms. Benick and Lohse (1974) assigned Atheta liturata to Atheta (Mischgruppe III, IV).