Atheta (Dimetrota) alphacrenuliventris Klimaszewski & Webster

Webster, Reginald P., Klimaszewski, Jan, Bourdon, Caroline, Sweeney, Jon D., Hughes, Cory C. & Labrecque, Myriam, 2016, Further contributions to the Aleocharinae (Coleoptera, Staphylinidae) fauna of New Brunswick and Canada including descriptions of 27 new species, ZooKeys 573, pp. 85-216 : 100-102

Taxon classification Animalia Coleoptera Staphylinidae

Atheta (Dimetrota) alphacrenuliventris Klimaszewski & Webster sp. n. Figs 76-83

Holotype (male).

Canada, New Brunswick, Northumberland Co., ca. 2.5 km W of Sevogle, 47.0876 N, 65.8613°W, 28.V.2013, R.P. Webster // old jack pine forest, vernal pond margin in coyote dung (LFC). Paratype: Canada, New Brunswick, Restigouche Co., Mount Atkinson, 447 m elev., 47.8192 N, 68.2618°W, 23.VI.2010, R.P. Webster, coll. // boreal forest, small shaded spring-fed brook with mossy margin, sifting moss (1 ♀, RWC).

Etymology.

A prefix alpha- added to the specific name crenuliventris, a species very similar to the new species.

Description.

Body length 3.2-3.6 mm, moderately narrow, elongate; head, pronotum, and abdomen dark brown to nearly black, elytra yellowish brown with triangular apical dark section near suture, legs yellowish brown or reddish brown, and antennae dark brown (Fig. 76); integument moderately glossy; forebody with meshed microsculpture and minute and dense punctation and pubescence; head rounded and slightly angular posterolaterally, with large eyes, longer than postocular area in dorsal view; antennae with articles V–X subquadrate to slightly transverse; pronotum rounded, slightly transverse, wider than head and distinctly narrower than elytra, pubescence directed laterad from midline of disk; elytra transverse, with pubescence directed posterolaterad and forming waves posteromedially; abdomen subparallel, narrower than elytra. Male. Median lobe of aedeagus with bulbus broad, tubus triangular in dorsal view (Fig. 77), and broad, straight ventrally, with apical part broadly elongate in lateral view (Fig. 78); internal sac with complex structures (Figs 77, 78); tergite VIII shallowly emarginate apically and sinuate, lateral proximity with small tooth on each side (Fig. 79); sternite VIII broadly parabolic (Fig. 80). Female. Tergite VIII truncate apically (Fig. 81); sternite VIII broadly rounded apically (Fig. 82); spermatheca club shaped, with narrow sac-shaped capsule bearing narrow apical invagination, stem sinuate half-looped posteriorly (Fig. 83).

Distribution.

Known only from NB, Canada.

Natural history.

One specimen was found in coyote dung on the margin of a vernal pond in a jack pine forest and another from moss along a small shaded spring-fed brook in a boreal ( spruce–fir) forest. Adults were collected during May and June.

Comments.

Atheta alphacrenuliventris is very similar externally and genitalically to Atheta crenuliventris Bernhauer and Atheta pseudocrenuliventris Klimaszewski. It may be distinguished from those two species by the absence of a crenulated apical margin on male tergite VIII (Fig. 79) and its differently shaped spermatheca (Fig. 83), and from Atheta crenuliventris , it differs by having the tubus of the median lobe of the aedeagus broader in lateral view (Fig. 78). Externally, its elytra are more reddish brown than those of Atheta crenuliventris , which are dark brown, and Atheta pseudocrenuliventris , which are light brown. The most reliable characters for distinguishing it from the other two species are genital characters (shape of the apical margin of male tergite VIII, shape of the median lobe of the aedeagus in lateral view, and shape of the spermatheca). (See Klimaszewski et al. 2011; Figs 112, 285 a–c, 412 for characters for comparison of Atheta pseudocrenuliventris with Atheta alphacrenuliventris ).