Anillinus alleni Sokolov and Carlton, 2017

Sokolov, Igor M., Carlton, Christopher E., Watrous, Larry E. & Robison, Henry W., 2017, Anillinus alleni Sokolov and Carlton (Coleoptera: Carabidae: Trechinae: Bembidiini), a New Species from the Ozark Interior Highlands of Arkansas, USA, The Coleopterists Bulletin 71 (2), pp. 289-297 : 290-295

Anillinus alleni Sokolov and Carlton , new species

Type Material. HOLOTYPE, male, deposited in U.S. National Collection, Smithsonian Institution , Washington, DC, glued on board, dissected, labeled: \ USA: AR: Stone Co., Blanchard Springs , 35.9560 -92.1778, 18-19 III 2014 ex. soil L. Watrous, H. Robison \.

PARATYPES: 1 male and 2 females (1 female dissected), deposited in Louisiana State Arthropod Museum , Baton Rouge, LA, labeled same as holotype .

Type Locality. USA: Arkansas, Stone County, Blanchard Springs, latitude 35.9560°, longitude -92.1778°.

Etymology. The specific epithet is a Latinized eponym in the genitive case. It is based on the surname of Robert T. (Tommy) Allen (1939–2016), the second author’ s graduate advisor, in honor of his contributions to knowledge of the biota of the Interior Highlands and for setting the authors on the path to rediscover this elusive species.

Recognition. Adults of this new species are distinguished easily from those of other species of the genus by the structure of the hind legs, specifically the modified metafemora in both sexes ( Fig. 1G, H ), especially the extremely elongate spinose processes of the metafemora of the males, and the male metatibiae covered with long setae.

Description. Large-sized for genus (SBL 2.50–2.51 mm, mean 2.51± 0.011 mm, n = 2). Habitus: Body form ( Fig. 3A ) subdepressed, slightly ovate, elongate (WE/SBL 0.37±0.005), head normally proportioned for genus (WH/WPm 0.74±0.054), pronotum moderately narrow in comparison to elytra (WPm/WE 0.77±0.039). Integument: Body color brunneo-rufous, appendages testaceous. Microsculpture absent from clypeus and vertex, obliterated on pronotal disc, distinct over frontal area of head, sides and base of pronotum, and elytra. Proepisternum (pes) with distinct microsculpture, prosternum (ps) smooth ( Fig. 1B ). 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). Fixed setae: Primary head setae typical of Anillina and include a pair of clypeal (cs), a pair of frontal (fs), and 2 pairs of supraorbital (ssa and ssp) setae ( Fig. 1A ). Mentum with 2 pairs of long primary (paramedial and lateral) setae and 2 shorter paramedial setulae ( Fig. 1D ). Submentum with 2 pairs of long primary setae in 2 rows (paramedial and lateral) and few additional shorter setulae ( Fig. 1D ). Pronotum with 2 long primary lateral setae (midlateral, ls, and basilateral, bs) on each side ( Fig. 1B ). Elytra with 3 discal setae ( Fig. 1C , ed3-4, 6), with scutellar (ed2) and apical (ed8) setae. Last 2 (8 th and 9 th) pores (eo8 and eo9) of umbilicate series much closer to each other than 7 th (eo7) to 8 th ( Fig. 1C ). Fifth visible sternite of male with 2 setae and of female with 4 setae along posterior margin. Head: Anterior margin of clypeus (cl) straight ( Fig. 1A ). Frontal area with subtle tubercle (ft) medially near frontoclypeal suture. Fronto-lateral carinae distinct and long. Labrum (l) transverse with concave anterior margin with 6 setae apically, increasing in size from central pair outwards. Labium ( Fig. 1D ) with mental tooth; mentum (m) and submentum (sm) split, with distinct mentalsubmental suture (ms). Glossal sclerite (gsc) with distinct paraglossae (pg) laterally and 2 setae medially. Prothorax: Pronotum ( Fig. 1B ) relatively small (LP/LE 0.36±0.019) and slightly transverse for genus (WPm/LP 1.30±0.084), with lateral margins shallowly sinuate and moderately constricted posteriorly (WPm/WPp 1.29±0.020). Anterior angles indistinct, posterior angles nearly rectangular (90–100°). Width between posterior angles much greater than between anterior angles (WPa/WPp 0.91±0.017). Basal margin straight. Prosternum ( Fig. 1E , ps) slightly protruding on anterior margin medially, there with a group of longer setae relative to other prosternal vestiture, without long ambulatory setae at middle of sclerite. Prosternal intercoxal process (psp) unmargined, slightly dilated apically, and semicircularly rounded at apex, with a row of sparse setulae along midline. Scutellum: Externally visible, widely triangular, with pointed apex ( Fig. 1C , sct). Elytra: Widely depressed along suture, comparatively long (LE/ SBL 0.61±0.018) and narrow for genus (WE/LE 0.61±0.023), with traces of 4–5 striae ( Fig. 1C ). Humeri indistinct, markedly rounded, in outline forming obtuse angle with longitudinal axis of body. Lateral margins subparallel, slightly divergent at basal fifth, evenly rounded to apex in apical third, without subapical sinuation. Basal margination distinct ( Fig. 1B–C , bm). Pterothorax: Metaventrite (mtv) short ( Fig. 1F ), distance between meso- and metacoxae (mtvx) about diameter of mesocoxa (mscx). Metendoventrite linear without lateral arms. Legs: Legs of moderate length, not elongate. Prothoracic legs of males with first tarsomere (ta1) markedly dilated apico-laterally with 2 rows of oval articulo-setae (as) ( Stork 1980) on ventral surface ( Fig. 2A ). Mesotibiae ( Fig. 2B ) with 1 row of modified posterodorsal setae (msms) at apical twothirds, with 2 terminal spurs (mss) and tibial brush (msb). Metafemora (mtf) modified in both genders: strongly curved with long, stout spine (sp) at apical third in males ( Fig. 1G ) and of normal shape with triangular enlargement at apical half in females ( Fig. 1H ). Metatibiae with modified hairy posterodorsal setae (mtms) in apical two-thirds in males ( Fig. 2C ) and without modified setae in females ( Fig. 2D ), with 2 terminal spurs (mts) and tibial brush (mtb). Tarsi pentamerous, last and 1 st tarsomeres the longest, tarsomeres 2–4 of equal length on tarsi of all legs, 1 st tarsomere shorter than combined length of tarsomeres 2–4. Tarsal claws simple, edentate. Abdominal ventrites: Five visible abdominal ventrites: 2 nd ventrite longest, 3.9 times longer than 3 rd or 4 th; 3 rd and 4 th equal in length; 5 th ventrite 2.3 times longer than 4 th. Intercoxal process (ipa) of 2 nd ventrite broad, tapering and truncated anteriorly ( Fig. 1F ). Width of process more than half (0.64) length of metacoxa. Male genitalia: Median lobe of aedeagus ( Fig. 3B ) anopic, with short basal lobe, long arcuate shaft with markedly dilated apical half, and apex truncate at tip (may be broken). Dorsal margin strongly sclerotized along almost entire length and in form of pronounced ridge (dr). Ventral margin enlarged and convex in apical half. Dorsal sclerite (ds) in form of a semicircular blade-like structure with short basal prolongations. Internal sac also with 2 spine-like structures and plates of distinctive shape (esp) in apicoventral area. Left paramere slightly enlarged apically and greatly so basally, ( Fig. 3C ), with 1 long seta. Right paramere long and moderately narrow, with 4–5 long setae ( Fig. 3D ). Female genitalia: Ovipositor sclerites ( Fig. 3F ) with gonocoxite 1 asetose (gc1). Gonocoxite 2 falciform (gc2), 1.7–1.8 times longer than basal width, markedly curved, with tiny ensiform (es) and normal nematiform (ns) setae. Laterotergite (lt) with 10–12 setae. Spermatheca ( Fig. 3E , sp) with distal part of cornu (dpc) markedly dilated. Nodulus (n) short, ramus practically undifferentiated ( Fig. 3E ).

Geographic Distribution. This species is known from the type locality in the Ozark Mountains of the Interior Highlands ( Fig. 4 ).

Natural History. Prior to his death, Thomas C. Barr, Jr. corresponded with HWR and shared his recollections about collecting the original, apparently lost, specimen of this species circa 1971. Relevant excerpts include: “The Blanchard Springs anilline will be under flat rocks in talus along the path leading to Blanchard Springs, itself, about 75–100 yd before you get to the springs…..to the right of the path as you walk to the spring outlet but not very far up the hill, because you are looking for as moist a well-drained microenvironment as possible.” (T. C. Barr email correspondence with HWR, 2005).

Specimens in the type series were extracted from soil using a soil-washing technique, thus implying an endogean habitat association. Their absence from numerous surface litter samples taken during previous years suggests a true specialization to a subterranean lifestyle that may include parts of the adjacent cavern system and surrounding karst topographies.

Comparison among Other Species. The structure of the internal genitalia unequivocally indicates relatedness between the new species and a complex of endogean species of Anillinus that occurs west of the Mississippi River. The shape of the apical part of the median lobe, specifically the enlarged and convex ventral margin, closely resembles that of A. aleyae Sokolov and Watrous , also from the Ozark Mountains, and A. lescheni Sokolov and Carlton , from the adjacent Ouachita Mountains to the south ( Sokolov et al. 2004; Sokolov and Watrous 2008), suggesting monophyly of the three species. The median lobe structure is less similar to members of the Texas assemblage of troglobitic and endogean species (Sokolov et al. 2014). Among endogean species from the eastern part of the genus’ range, the Appalachian moseleyae group of species ( Sokolov 2011) is most similar to A. alleni in the shape of the median lobe. The shape of the spermatheca, namely the markedly dilated distal part of the cornu of the new species, is similar to that of the Texas species A. forthoodensis Sokolov and Reddell (Sokolov et al. 2014). The combination of external characteristics of A. alleni is unique among congeners from the western part of the genus’ range (i.e., west of the Mississippi River), whereas among the species from the east the new species resembles the Alabama troglobitic species A. valentinei (Jeannel) and, especially, A. tombarri Sokolov , sharing with the latter unusually large size, wide basal margin of the pronotum, and spinose male metafemora ( Sokolov 2012).

Figures

Fig. 1. SEM images of body parts of Anillinus alleni. A) Head, dorsal view, B) Pronotum, dorsal view, C) Elytra, dorsal view, D) Head, ventral view, E) Prosternum, ventral view, F) Metasternum, ventral view, G) Left and right metafemora, male, H) Right metafemur, female. bm = basal emargination; bs = basolateral pronotal seta; cl = clypeus; cs = clypeal seta; ed2 = scutellar seta; ed3-4, 6 = 1st, 2nd, and 3rd fixed discal setae; ed8 = apical seta; eo1-9 = setae 1–9 from the umbilicate series; fs = frontal seta; ft = frontal tubercle; gsc = glossal sclerite; ipa = intercoxal process of abdominal ventrite 2; lb = labrum; ls = midlaterall pronotal seta; m = mentum; mp3 = maxillary palpomere 3; mp4 = maxillary palpomere 4; ms = mental-submental suture; mscx = mesocoxa; mtcx = metacoxa; mtf = metafemur; mtt = metatibia; mttr = metatrochanter; mtv = metaventrite; pep = proepipleuron; pes = proepisternum; pg = paraglossa; prcx = procoxa; ps = prosternum; psp = prosternal process; sct = scutellum; sm = submentum; sp = metafemoral spine; ssa = anterior supraorbital seta; ssp = posterior supraorbital seta. Scale bars: A–B, E–H = 0.2 mm; C = 0.5 mm; D = 0.1 mm.

Fig. 3. Habitus and internal genitalia of Anillinus alleni. A) Habitus, B) Aedeagal median lobe, right lateral view, C) Left paramere, left lateral view, D) Right paramere, right lateral view, E) Spermatheca and apical part of spermathecal gland, F) Female right ovipositor sclerites, dorsal view. bl = blade of gonocoxite 2; dpc = distal part of cornu; dr = dorsal ridge of median lobe; ds = dorsal sclerites of median lobe; es = ensiform setae; esp = endofallic spines of median lobe; gc1 = gonoxocite 1; gc2 = gonocoxite 2; lt = laterotergite; n = nodulus; ns = nematiform seta; ppc = proximal part of cornu; sg = spermathecal gland; sp = spermatheca. Scale bars: A = 0.5 mm; B = 0.2 mm; E–F = 0.1 mm.

Fig. 2. SEM illustrations of structural features of the legs of Anillinus alleni. A) Left foreleg, male, dorsal view, B) Right mesotibia, female, ventral view, C) Left metatibia, male, ventro-lateral view, D) Left metatibia, female, medial view. as = adhesive seta; msb = mesotibial brush; msms = mesotibial modified seta; mss = mesotibial spur; mtb = metatibial brush; mts = metatibial spur; mtts = metatibial modified setae; ta1-ta3 = protarsomeres 1–3; tbn = tibial notch. Scale bar = 0.2 mm.

Fig. 4. Locality records for Anillinus species from the Ozark and Ouachita Mountains: A. alleni – red star; A. aleyae – white diamonds; A. magazinensis Sokolov and Carlton – white circles; A. lescheni – white triangle; A. robisoni Sokolov and Carlton – white flowers; A. stephani Sokolov and Carlton – black square; A. tishechkini Sokolov and Carlton – white squares (Sokolov et al. 2004; Sokolov and Watrous 2008; personal observations).