Serranillus septentrionis Sokolov and Carlton

Sokolov, Igor M. & Carlton, Christopher E., 2008, Two new species of blind, forest litter-inhabiting ground beetles from the subtribe Anillina (Carabidae: Trechinae: Bembidiini) from eastern U. S. A., Zootaxa 1740, pp. 37-44 : 38-40

Serranillus septentrionis Sokolov and Carlton , new species

Holotype. Male labeled / VIRGINIA: Botetourt Co., Blue Ridge Pwy., Black Horse Gap, 37°25.33’ N 79°45.43’ W, 745m. Litter sifting, 2 May 2006 A.K.Tishechkin / / HOLOTYPE, Serranillus septentrionis Sokolov and Carlton , des. 2007/. Deposited U.S. National Museum ( USNM).

Type locality. U.S. A, VA, Botetourt Co., Blue Ridge Pwy., Black Horse Gap, 37°25.33’ N 79°45.43’ W.

Paratypes (6). One male and 1 female with same data as holotype; 1 male labeled / USA –VA: Giles Co., Jefferson NF, Flat Top Mt., at 37°14.6’ N 80°52.0’ W, forest litter, 1120m, C.E.Carlton 25 May 2006 /; 2 males labeled / USA –VA: Giles Co., Jefferson NF, Flat Top Mt., at 37°14.0’ N 80°52.5’ W, 1080m, forest litter, C.E.Carlton 25 May 2006 /; 1 female labeled / USA –VA: Giles Co., Jefferson NF, Flat Top Mt., at 37°13.8’ N 80°52.4’ W, hardwood berlese, 400m, C.E.Carlton 25 May 2006 /. Deposited Louisiana State Arthropod Museum ( LSAM).

Etymology. The specific epithet " septentrionis " (Latin, “the northern regions, the northern countries, the north”) is an adjective referring to the geographic range of the species, the most northern among known species of the genus.

Description. Large for genus (ABL range 2.00– 2.14mm, mean 2.07± 0.053 mm, n=7). Sexes of approximately equal size: size of males ABL range 2.00– 2.14mm, mean 2.06± 0.055 mm, n=5, size of females ABL range 2.04–2.13mm, mean 2.09± 0.064 mm, n=2. Habitus ( Fig. 1 ) markedly convex, ovoid (WE/ABL 0.39+0.010), head normally proportioned for genus (WH/WPm 0.72+0.017), pronotum narrow compared to elytra (WPm/WE 0.79+0.011). Body color dark, from dark brunneous to brunneorufous, appendages much lighter, testaceous. Microsculpture fine but distinct across dorsal surface of pronotum and most of head. On head only the vertex lacks microsculpture. Elytra with well-developed polygonal microsculpture.

Pronotum moderately convex and comparatively strongly transverse (WPm/LP 1.33+0.043), with margins rectilinear and moderately constricted posteriad (WPm/WPp 1.31+0.032). Anterior angles evident, slightly prominent. Posterior angles slightly obtuse (105–110°). Width between posterior angles slightly greater than between anterior angles (WPa/WPp 0.97+0.027).

Elytra markedly convex, slightly depressed along suture, of normal length for genus (LE/ABL 0.58+0.015), with traces of 1–2 interneurs. Humeri moderately prominent, in outline forming an obtuse angle with longitudinal axis of body, dorsally moderately rounded, gradually enlarged to middle. Margins subparallel, slightly divergent in basal half, evenly rounded to apex, maximum width of elytra behind midpoint. Elytra without subapical sinuation. Vestiture of elytra long (about half length of discal setae).

Prothoracic leg of males with strongly dilated tarsomere 1 and moderately dilated tarsomere 2. Profemur moderately swollen. Metafemora unmodified.

Males with three denticles on the apex of the sternum VII.

Median lobe ( Fig. 3 ) nearly straight, with elongate, gradually narrowing and somewhat acute apex, ventral margin with obvious striation and few poriferous canals. Canals absent on walls of median lobe itself. Copulatory sclerites represented by two weakly sclerotized plates, subquadrate in form and one after the other in position. Walls of invagination of apical orifice obviously sclerotized and forming a wavy contour.

Left paramere ( Fig. 4 ) with enlarged base, which is distinctly separated by a wide border from the distal part of the paramere; paramere apex without visible setae (at X400). Right paramere absent.

Spermatheca ( Fig. 5 ) moderately sclerotized, with three well-developed parts. Distal part, the cornu, is sclerotized and bean-like in form, more than 2 times longer than wide. Proximal part of cornu unsclerotized and straight, with traces of coils. Ramus well-differentiated, sclerotized, ovoid. Nodulus short. Spermathecal duct comparatively short, more or less straight, without obvious coils.

Stylomeres and sternum IX as in Figure 6 . Sternum with 8–9 setae.

Distribution. Known from Giles and Botetourt Counties, Virginia.

Habitat. Beetles were collected in litter of deciduous hardwood forest from a wide range of altitudes (400–1100m).

Differential diagnosis. Serranillus septentrionis in general outline is very similar to S. jeanneli , but easily distinguished from the latter by the form of the apex of the median lobe. The latter species has comparatively shorter and subparallel apex of median lobe with a rounded tip. In comparison with S. dunavani the new species is noticeably larger and has a comparatively smaller head. Additionally, the range of the new species is far north of the ranges of both previously known species of Serranillus ( Fig. 7 ).

Figures

FIGURE 7. Schematic distribution of the Serranillus species. 1 – S. jeanneli Barr; 2 – S. dunavani (Jeannel); 3 – S. septentrionis, new species. From Barr (1995) and original data.

FIGURES 1 – 2. Habitus of (1) Serranillus septentrionis, new species (VA, Botetourt Co., Black Horse Gap), and (2) Anillinus cherokee, new species (TN, Blount Co., Great Smoky Mountains National Park), dorsal aspect, males.

FIGURES 3 – 6. Serranillus septentrionis, new species, (VA, Giles Co., Jefferson National Forest). Male aedeagus: 3 – median lobe, 4 – left paramere; female genitalia: 5 – spermatheca, 6 – right stylomere and sternum IX. Scale = 100 μm.