Anillinus robisoni Sokolov and Carlton

Sokolov, Igor M., Carlton, Christopher & Cornell, James F., 2004, Review of Anillinus, with Descriptions of 17 New Species and a Key to Soil and Litter Species (Coleoptera: Carabidae: Trechinae: Bembidiini), The Coleopterists Bulletin 58 (2), pp. 185-233 : 223-224

Anillinus robisoni Sokolov and Carlton , new species

( Figs. 4 , 9 , 35 , Map fig. 40)

Holotype ( USNM). Male labeled / USA, AR, Polk Co., 5.0 mi SW Big Fork, Decid. berl., Carlton and Robison, 4 Apr 1992 / C.E.Carlton Collection / LSAM0017121 / HOLOTYPE, Anillinus robisoni Sokolov and Carlton , des. 2003/.

Paratypes (14, LSAM). Two males and 2 females labeled / USA, AR, Montgomery Co., Little Mo. Falls Rec. Ar., Slopes SW of river, Decid.forest berlesate, Carlton / Robison, 26 Jul 1991 /; 1 male labeled / USA, AR, Montgomery Co., Lit. Mo. Falls Rec. Area , Decid. berl., Carlton and Robison, 6 Jun 1992 /; 1 female labeled / USA, AR, Montgomery Co., 1.5 mi E Cryst. Rec. Area, Slopes at FS.177K, Decid.forest berlesate, Carlton / Robison, 26 Jul 1991 /; 1 male labeled / USA, AR, Montg. Co., N edge Albert Pike Rec. Area , Decid. berl., Carlton and Robison, 24 Aug 1991 /; 1 female labeled / USA, AR, Polk Co., Caney Crk. W. A., Carlton / Robison, 25 Jul 1991 /; 1 female labeled / USA, AR, Polk Co., Caney Crk. Wild. Ar., 3.5 mi N Bard Spgs. , leaf lt./flood berlesate, Carlton / Robison, 23 Aug 1991 /; 1 female labeled / USA, AR, Polk Co., Caney Crk. Wild. Ar., 3.5 mi N Bard Spgs., Maple , beech berlesate, Carlton / Robison, 28 Sept 1991 /; 1 female labeled / USA, AR, Polk Co., Caney Crk. Wild. Ar., 3.0 mi N Bard Spgs., Beech-maple berlesate, Carlton / Robison, 19 Oct 1991 /; 1 female labeled / USA, AR, Polk Co., Caney Crk. Wild. Ar., 3.5 mi N Bard Spgs., Beech-maple berlesate, Carlton / Robison, 7 Mar 1992 /; 1 female labeled / USA, AR, Polk Co., Caney Crk. Wild. Ar., 3.5 mi N Bard Spgs., Decid. berl., Carlton and Robison, 24 Mar 1992 /; 1 female labeled / USA, AR, Polk Co., Caney Crk. Wild. Ar., 3.5 mi N Bard Spgs., Beech-maple berlesate, Carlton / Robison, 3 Apr 1992 /.

Specific Epithet. This species is named after Henry Robison (Southern Arkansas University, Magnolia, AR), co-collector of the type series and enthusiastic student and teacher of Arkansas natural history.

Description. Medium to large-sized for genus (ABL range, 1.77–2.11 mm; mean, 1.92 mm, n ¼ 15). Habitus slightly convex, elongate (WE/ABL, 0.36) with head normally proportioned for genus (WH/WPm, 0.76) ( Fig. 4 ) and with narrow pronotum and elytra (WPm/WE, 0.80). Color of body varies from rufotestaceous to amber testaceous, appendages testaceous. Microsculpture of head extended over vertex and various on anterior parts of frons ( Fig. 4 ). Microsculpture of pronotum absent from disc.

Pronotum ( Fig. 9 ) moderately convex, more elongate than in most species of genus (WPm/LP, 1.27), with margins markedly constricted posteriad (WPm/WPp, 1.42) and slightly sinuate before the posterior angles ( Fig. 9 ). Anterior angles almost effaced. Posterior angles nearly rectangular (95–1008). Width between anterior angles slightly greater than width between posterior angles (WPa/WPp, 1.06).

Elytra slightly convex, widely depressed along suture, of normal length for genus (LE/ABL, 0.57), with traces of 4–5 interneurs. Humeri slightly prominent, markedly rounded. Vestiture of elytra relatively long (one third to one-fourth the length of discal setae), approximately the same length as vestiture on disc of pronotum.

Males with metafemora modified; bearing a small obtuse denticulate projection along posterior margin in apical third.

Median lobe ( Fig. 35 ) large, slightly arcuate, with enlarged axiniform apex. Internal sac with copulatory pieces with a variety of structures: dorsal and ventral sclerites and patches of spines. Dorsal sclerites short and large, together in form of angulate stick-like structures. Ventral sclerite large, of complicated plate-like form and located immediately over the apex. A group of large spines occupies outermost apical position, crossed in lateral view by the apical parts of dorsal and ventral sclerites.

Distribution. Known from the southern parts of the Ouachita National Forest in the vicinity of Shady Lake and Bard Springs Recreation Areas near the boundary between Polk and Montgomery Co., Arkansas ( Fig. 40).

Habitat. Specimens were collected from Berlese samples of deep forest litter in hardwood and pine/hardwood forests (see Carlton and Robison 1998 for details about beetle diversity in this area).

Differential Diagnosis. Anillinus robisoni is parallel-sided with microsculpture effaced on the forebody ( Table 2, group VII of endogean species). It is distinguished from all other species in this group (for which males are known) by the form of the median lobe and the presence of elytral interneurs laterad the discal setae.

This species is allopatric with respect to other described species of Anillinus . From its geographically closest congeners it differs by its size and by the smooth forebody; and by features mentioned in the key.

Variation. The form of the median lobe of this species varies in the degree of development of the axe-shaped apex. Whether this variation reflects individual or population-level variation, or even the degree of maturity of the specimen is difficult to say because of the scarcity of male specimens. The armature of the internal sac seems to be constant in all cases.

Figures

Figs. 1–5. Anillinus spp. 1) Anillinus fortis (Horn), dorsal aspect, scale ¼ 1.0 mm. 2–7) Dorsal aspects of heads, showing microsculpture, scale ¼ 0.2 mm. 2) Anillinus magazinensis n. sp.; 3) A. fortis (Horn); 4) A. robisoni n. sp.; 5) A. erwini n. sp.

Figs. 6–9. Pronota of Anillinus spp., scale ¼ 0.3 mm. 6) Anillinus erwini n. sp.; 7) A. fortis

Figs. 32–37. Aedeagi of Anillinus spp., right lateral aspects, scale ¼ 0.1 mm. 32) A. magazinensis n.sp.; 33) A. moseleyae n.sp.; 34) Anillinus murrayae n.sp.; 35) A. robisoni n. sp.; 36) A. stephani n. sp.; 37) A. tishechkini n. sp.