Anillinus albrittonorum Sokolov & Schnepp, 2021

Sokolov 1, Igor M. & Schnepp 2, Kyle E., 2021, A new subterranean species of Anillinus Casey (Carabidae, Trechinae, Anillini) from Florida, Subterranean Biology 39, pp. 33-44 : 33

Anillinus albrittonorum Sokolov & Schnepp sp. nov. Figs 1 , 2 , 3 , 4

Type material.

Holotype: male (NMNH), dissected, labeled "FLORIDA: Columbia Co., 6mi NW High Springs, 29.8674°N, 82.6664°W, May 6 - August 5, 2020, underground column trap, Kyle E. Schnepp".

Paratypes (22 specimens). Same data as holotype [1 male, CUAC; 2 males, KESC; 1 male, 1 female, NMNH]; same data except November 11, 2019 - March 8, 2020 [1 female, FSCA]; March 8 - May 6, 2020 [2 females, CUAC, FSCA]; August 5 - September 25, 2020 [2 males, 3 females, KESC]; September 25 - October 16, 2020 [1 male, 5 females, FSCA]; October 16 - December 3, 2020 [1 male, 2 females, KESC].

Etymology.

This species is named in honor of the Albritton family, Matthew, Pam, Rowan, and Henry, whose interest and assistance in collecting brought about the discovery of this beetle.

Type locality.

USA, Florida, Columbia County, 6 miles northwest High Springs, 29.8674°N, 82.6664°W (Figs 1 , 2 ).

Diagnosis.

Adults of A. albrittonorum can be distinguished from both Florida species of Anillinus by its subparallel, elongate, only slightly convex habitus. Anillinus kovariki and A. dohrni belong to the group of species with ovoid and convex habitus (cf. description of A. dohrni "Testaceus, robustus ovatus supra convexus …”, Ehlers 1884, p. 36). Additionally, adults of the new species can be distinguished from those of other subterranean members of Anillinus by details of the microsculpture of the head and pronotum. The presence of a smooth frons with completely microsculptured vertex of the head and a smooth pronotal disc with a distinctively microsculptured base is distinctive. Males and females of A. albrittonorum can also be distinguished from congeners by the structure of their genitalia.

Description.

Moderate-sized for the genus (ABL 1.56-1.92 mm, mean 1.71 ± 0.094 mm, n = 17). Males (ABL 1.70-1.92 mm, mean 1.78 ± 0.098 mm, n = 5) slightly larger than females (ABL 1.56-1.88 mm, mean 1.69 ± 0.082 mm, n = 12).

Habitus: Body form (Fig. 3A ) slightly convex, subparallel, elongate (WE/ABL 0.33 ± 0.006), head moderately large in comparison to pronotum (WH/WPm 0.77 ± 0.017), pronotum large relative to elytra (WPm/WE 0.88 ± 0.021).

Integument: Body color brunneo-rufous, appendages testaceous. Microsculpture (Fig. 3B, C ) present on vertex, base of pronotum, and on elytra where it is represented by isodiametric polygonal sculpticells; and absent from clypeus and frons on head, and from disc of pronotum. Body surface shiny, surface sparsely and finely punctate, covered with sparse, yellowish, short setae. Vestiture of elytra short (~0.3 × the length of discal setae).

Prothorax: Pronotum (Fig. 3C ) moderately convex, of moderate size (LP/LE 0.40 ± 0.012) and moderately transverse (WPm/LP 1.24 ± 0.024), with lateral margins almost rectilinearly and moderately constricted posteriorly (WPm/WPp 1.26 ± 0.025). Anterior angles indistinct, posterior angles almost rectangular (89-100°). Width between posterior angles equals the width between anterior angles (WPa/WPp 1.00 ± 0.023). Basal margin slightly concave in middle.

Scutellum: Externally visible, triangular, with pointed apex.

Elytra: Slightly convex, of average length (LE/ABL 0.58 ± 0.006) and width (WE/LE 0.57 ± 0.011) for the genus, with traces of 5-6 striae. Humeri distinct, rounded, in outline forming an obtuse angle with longitudinal axis of body. Lateral margins subparallel in middle, slightly convergent at basal fifth, evenly rounded to apex at apical third, with shallow subapical sinuation. Basal margination distinct.

Legs: Protarsi of male with moderately dilated tarsomere I. Profemora moderately swollen.

Males with metafemora modified; each bearing a small projection with small tubercles at posterior margin. Females metafemora unmodified.

Male genitalia: Median lobe (Fig. 4A ) of aedeagus anopic, moderately arcuate and moderately twisted. Shaft slightly dilated in apical half, enlarged trianguloid apex with sides almost rectangularly tapered to narrowly rounded tip. Apical orifice long, occupies almost half of the shaft length. Ventral margin of median lobe curved, most strongly bent at the middle of shaft, with abrupt enlargement before apex, without poriferous canals. Dorsal copulatory sclerites short, fused to form slightly curved blade-like structure. Spines and scaled membranous folds of internal sac absent. Left paramere (Fig. 4B ) of shape common in the genus, paramere apex with two long setae. Right paramere (Fig. 4C ) of moderate length, bearing four long setae, which are approximately the length of paramere.

Female genitalia: Spermatheca (Fig. 4E ) slightly sclerotized, formed from two compartments of different width and shape. The distal compartment of a bean-like shape, wide and long, occupies two-thirds of the spermatheca length, and presumably corresponds to the cornu of other species of the genus. Proximal part cylindrical, short and narrow, presumably corresponds to the fused ramus and nodulus of other species of the genus (cf. Fig. 4E with the spermatheca of A. cherokee Sokolov and Carlton on fig. 11 in Sokolov and Carlton 2008, p. 43). Length of spermathecal gland shorter than length of spermatheca. Spermathecal duct long and uncoiled. Gonocoxite II slightly falciform, more than 2 × longer than it is wide basally, with acute ensiferous setae (Fig. 4D ). Laterotergite with 7-8 setae (Fig. 4D ).

Geographic distribution.

This species is known only from the type locality in the High Springs area of Columbia County, Florida (Fig. 1 ).

Habitat.

All specimens of this species were collected from deep sand soil using underground column pitfalls. The underground traps used are comprised of ½ inch hardware cloth tied into a cylinder with PVC plastic pipe on each end. Each section of pipe is 10 inches in length and the hardware cloth is two feet long. The cloth overlaps with each pipe approximately 2 inches, resulting in a trapping length of 20 inches. The effective trapping depth is from 10 inches to 30 inches below the soil surface. A plug of soil the size of the trap is removed from the ground and the trap installed in the hole. A jar containing propylene glycol with a funnel on top the same diameter as the pipe is lowered to the bottom and is used to collect and preserve insects burrowing through the sand. These traps were placed in an area of deep sand on the north end of the northern Brooksville ridge, one of many “islands” of elevated karst and sand that cover Florida. There are numerous ridge systems in Florida, generally running north to south, that were beach dunes formed by past fluctuations in ocean levels ( Bousquet and Skelley 2010, 2012). The type locality and surrounding area is mostly disturbed sandhill with secondary growth and pastureland (Fig. 2 ). Other carabid species collected in the same traps that are regarded as interesting, rare, and indicators of the subterranean habitat include Clivina choatei Bousquet and Skelley and Scarites stenops Bousquet and Skelley. Anillinus albrittonorum is a true endogean species and has never been found in litter samples.

Relationships.

The new species belongs to group VII of the endogean Anillus species ( Sokolov et al. 2004), characterized by a combination of the partly microsculptured head and a smooth disc of the pronotum. However, A. robisoni Sokolov and Carlton from Arkansas and species of the Anillinus moseleyae group from North Carolina that form group VII of the endogean species have only a superficial similarity to the new species. Within this group, as well as within other groups of the endogean and litter species, A. albrittonorum differs in the structure of its spermatheca from all Anillinus species where the spermathecae have been examined. Among endogean species with similar habitus, the range of A. albrittonorum is geographically (Fig. 1 ) close to the range of A. turneri Jeannel, described from the Atlanta area (Peach County) in Georgia. Externally, both species can be distinguished by the structure of the frons, completely microsculptured in specimens of A. turneri but smooth in the specimens of A. albrittonorum . Both species can also be distinguished based on the male and female genital structures. The spermatheca of females of A. turneri (Peach Co., Georgia, NMNH) have a question-mark shape, typical for Anillinus , and thus shows no similarity to the spermatheca of females of A. albrittonorum . As it was mentioned above, two Florida species, A. dohrni and A. kovariki , exemplify ovoid and convex species, i.e. belong to other morphological groups of species, and in comparison with A. albrittonorum demonstrate quite dissimilar genital structures. The male median lobes of both Florida species have simple, not enlarged apices, and shafts of different shapes (cf. Fig. 4A with the male median lobe of A. dohrni on fig. 64 in Jeannel 1963a, p. 75, and the male median lobe of A. kovariki on fig. 28 in Sokolov et al. 2004, p. 194).

Figures

Figure 1. Map of Florida and Georgia showing positions of the known locality records for three species of Anillinus.

Figure 2. Habitat and type locality of Anillinus albrittonorum sp. nov. Underground traps indicated by a pair of flags in foreground and background.

Figure 3. Digital images of external features of Anillinus albrittonorum sp. nov. (female, 6 mi NW High Springs, Columbia County, Florida) A habitus, dorsal aspect B head, dorsal aspect C pronotum, dorsal aspect. Scale bars: 0.5 mm (A); 0.2 mm (B, C).

Figure 4. Digital images of male and female genitalia of Anillinus albrittonorum sp. nov. (6 mi NW High Springs, Columbia County, Florida). Male genitalia: A median lobe, right lateral aspect; apex to upper left and basal bulb to lower right B left paramere, left lateral aspect C right paramere, right lateral aspect. Female genitalia: D ovipositor sclerites E spermatheca. Scale bars: 0.1 mm.