Anillinus humicolus Sokolov, 2020

Sokolov, Igor M., 2020, Four new species of the genus Anillinus Casey (Coleoptera, Carabidae, Anillini) from Alabama, U. S. A., with a revised key to the Alabama species, Zootaxa 4808 (3), pp. 547-559 : 553-555

Anillinus humicolus Sokolov , sp. n.

( Figs. 1D , 2D , 3D , 4 J–L, 5)

Type material. Holotype, one male ( CMNH), dissected, labeled: \ ALABAMA: Jefferson Co. Cherokee Bend, Mountain Brook nr Birmingham, T. N.King, July 10 1971 \ [computer printed] \ THOMAS C. BARR COLLEC- TION 2001 ACC. No. 38,014 \ [computer printed] \ 7/10/71 M B \ [handwritten].

Specific epithet. Species name originates from the Latin adjective “ humicolus ” meaning “soil-dwelling”, and refers to the presumable habitat of the new species.

Type locality. USA, Alabama, Jefferson County, Mountain Brook (suburb of Birmingham) .

Differential Diagnosis. Males of A. humicolus can be distinguished from those of the other congeners by the effaced microsculpture on the head and pronotum, and the structure of the median lobe with numerous big spines in the internal sac.

Description. Medium-sized for genus (ABL 1.88 mm).

Habitus: Body form ( Fig. 1D ) moderately convex, elongate ovoid (WE/ABL 0.38), head wide relative to pronotum (WH/WPm 0.74), pronotum moderately narrow in comparison to elytra (WPm/WE 0.81).

Integument: Body color brunneo-piceous, appendages testaceous. Microsculpture greatly reduced; head and pronotum without microsculpture except small triangular area at the middle of vertex with several polygonal meshes ( Fig. 2D ); elytra with well-developed polygonal microsculpture. Body surface shiny, surface sparsely and finely punctate, covered with sparse, yellowish, short setae. Vestiture of elytra moderately long (0.3–0.4 length of discal setae).

Prothorax: Pronotum ( Fig. 2D ) moderately convex, of moderate size (LP/LE 0.40), moderately transverse (WPm/LP 1.32), with lateral margins slightly and rectilinearly constricted posteriorly (WPm/WPp 1.18). Anterior angles indistinct, posterior angles slightly obtuse (110°). Width between posterior angles much greater than between anterior angles (WPa/WPp 0.88). Basal margin slightly concave in middle.

Scutellum: Externally visible, triangular, with narrowly rounded apex.

Elytra: Narrowly depressed along suture, with traces of 1–2 striae, of length (LE/ABL 0.58) and width (WE/LE 0.66) average for genus. Humeri distinct, rounded, in outline forming right angle with longitudinal axis of body. Lateral margins subparallel in middle, slightly divergent at basal fifth, evenly rounded to apex in apical third, without subapical sinuation. Basal margination distinct.

Legs: Protarsi of male with moderately dilated tarsomere 1. Profemora moderately swollen. Metafemora unmodified.

Male genitalia: Median lobe ( Fig. 4J ) of aedeagus anopic, slightly arcuate and slightly twisted. Shaft elongate, subparallel, with elongate subparallel apex, with rounded tip. Ventral margin of median lobe straight, not enlarged, without poriferous canals. Dorsal copulatory sclerites in form of fused, intertwining blade-like structures slightly widening basally, shaped like an arc with ends facing dorsally, and situated at the middle of shaft. Between dorsal sclerites and apical orifice internal sac has a scaly membranous field with a group of eleven big spines. Left paramere ( Fig. 4K ) of shape common in genus, paramere apex with two short setae. Right paramere ( Fig. 4L ) short, with four long setae apically, which are equal to the length of paramere.

Geographic Distribution. This species is known only from Jefferson County, Alabama ( Fig. 5 , black diamond).

Habitat. The label does not contain any information about subterranean habitat or about any other habitat. Presumably this species is not a cavernicolous species.

Relationships. Based on the structure of the median lobe, A. humicolus is a sister species to the cavernicolous A. valentinei Barr (cf. Fig. 6G , page 68 in Sokolov 2012). The latter is known to occur in Jefferson County, where it was documented from Crystal Caverns ( Peck 1995; Sokolov 2012) situated approximately 16 miles to the NE of the type locality of A. humicolus .

Figures

FIGURE 1. Digital images of habitus of Anillinus species, dorsal aspect. A—A. clinei (Stewart Cave, Jackson County, Alabama), B—A. folkertsioides (Creek Cave, Marshall County, Alabama), C—A. hildebrandti (Cave Springs Cave, Morgan County, Alabama), D—A. humicolus (Mountain Brook, Jefferson County, Alabama). Scale bar 0.5mm.

FIGURE 2. Digital images of pronota of Anillinus species, dorsal aspect. A—A. clinei (Stewart Cave, Jackson County, Alabama), B—A. folkertsioides (Creek Cave, Marshall County, Alabama), C—A. hildebrandti (Cave Spring Cave, Morgan County, Alabama), D—A. humicolus (Mountain Brook, Jefferson County, Alabama). Scale bar 0.2mm.

FIGURE 3. Variation of microsculpture patterns among the Alabama Anillinus. A—A. clinei (Stewart Cave, Jackson County, Alabama), B—A. folkertsioides (Creek Cave, Marshall County, Alabama), C—A. hildebrandti (Cave Spring Cave, Morgan County, Alabama), D—A. humicolus (Mountain Brook, Jefferson County, Alabama). Areas with microsculpture are shaded.

FIGURE 4. Line drawings of male genitalia of Anillinus species. A. clinei (Stewart Cave, Jackson County, Alabama): A—median lobe, right lateral aspect, B—left paramere, left lateral aspect, C—right paramere, right lateral aspect. A. folkertsioides (Creek Cave, Marshall County, Alabama): D—median lobe, right lateral aspect, E—left paramere, left lateral aspect, F—right paramere, right lateral aspect. A. hildebrandti (Cave Spring Cave, Morgan County, Alabama): G—median lobe, right lateral aspect, H—left paramere, left lateral aspect, I—right paramere, right lateral aspect. A. humicolus (Mountain Brook, Jefferson County, Alabama): J—median lobe, right lateral aspect, K—left paramere, left lateral aspect, L—right paramere, right lateral aspect. Scale bar 0.1mm.

FIGURE 5. Locality records for the newly described species of Anillinus: A. clinei, black cross; A. folkertsioides, red stars; A. hildebrandti, yellow circle; A. humicolus, black diamond. Physiographic regions of Alabama (Fenneman 1938) numbered as follows: 1—Highland Rim; 2—Cumberland Plateau; 3—Alabama Valley and Ridge; 4—Piedmont Upland.

FIGURE 6. Species distribution of Anillinus in the eastern USA and factors shaping the genus diversity. A—total species number and number of endemics per state in the territory to the east of the Mississippi River (only described species included in Bousquet 2012, Sokolov 2012, 2014). Here and elsewhere state abbreviations follow Federal Information Processing Standards (https://www.nlsinfo.org/content/ cohorts/nlsy79/other-documentation/codebook-supplement/nlsy79-attachment-102-federal); B—species compositions in accordance with their habitat preferences in the three most speciose states of the E USA; C—biplot graph with clusters of states grouped on the basis of state species compositions using PCA analysis (explanation in the text). Green lines—projections of loadings of the following variables: ComEnd—number of common endogean species, ComLitnumber of common litter species, EndEnd—number of endemic endogean species, EndLit—number of endemic litter species, EndTrogl—number of endemic troglobitic species.