Anillinus castaneus Harden & Caterino, 2024, sp. nov.
Creators: name: Harden, Curt W.
name: Caterino, Michael S.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Carabidae
Anillinus
Anillinus castaneus

description: Anillinus castaneus sp. nov.   
Figs 21 C, 24 B, 29, 30 A – C, 32 A, D  
Type material.  
  Holotype male (USNM) : point mounted, with genitalia in Euparal on microslide pinned beneath specimen. Original label: “ USA: S. Carolina: Greenville Co. Chestnut Ridge Heritage Pres. N 35.1471, W -82.2841. 8 April 2018 (373) Sift / Berl CWD 5 M. Ferro ” “ CLEMSON-ENT CUAC 000080962 ” “ HOLOTYPE Anillinus castaneus Harden & Caterino [orange cardstock] ”   
 Paratypes (n = 9, CUAC). USA • South Carolina • Greenville Co.; Chestnut Ridge Heritage Preserve; • 2 ♀; same data as holotype; CUAC 000080963 and CUAC 000080964; • 1 ♀; Greenville Co.; Chestnut Ridge Heritage Preserve; 35.1506, - 82.2779; 8 Apr. 2018; M. Caterino & L. Vasquez leg.; sifted litter; CUAC 000108120; • 2 ♂; Greenville Co.; Chestnut Ridge Heritage Preserve; 35.1523, - 82.2814; 5 Jun. 2015; S. Myers leg.; Hardwood litter; CUAC 000170064 and CUAC 000170065, SSM 098 and SSM 099 [these two specimens do not have molecular voucher labels, but have been extracted and bear identical locality data to that entered for these voucher numbers by S. Myers]; • 1 ♀; Greenville Co.; Chestnut Ridge Heritage Preserve; 35.1501, - 82.2820; 5 Jun. 2015; S. Myers leg.; Hardwood litter; CUAC 000170066, SSM- 101; • 1 ♀; Greenville Co.; Chestnut Ridge Heritage Preserve; 35.14970, - 82.28207; 20 Oct. 2021; C. W. Harden leg.; On underside of large rock beside rivulet; CUAC 000170067, CWH- 415; • 1 ♀; Greenville Co.; Chestnut Ridge Heritage Preserve; 35.1507, - 82.2821; 15 Mar. 2022; C. W. Harden leg.; Berlese, deep duff / soil; CUAC 000170068; • 1 ♀; Greenville Co.; Chestnut Ridge Heritage Preserve; 35.1406, - 82.2790; 5 Jun. 2015; S. Myers leg.; Secondary litter; CUAC 000025521.   
GenBank accession numbers for paratypes: OR 839224, OR 853178, OR 839223, OR 839749, OR 837941, OR 838100, OR 838278, OR 853179, OR 839821, OR 838112, OR 838296.  
Diagnosis.  
 A moderately large typical member of the valentinei group, externally similar to A. murrayae and A. cornelli (Fig. 32 A). The male genitalia are distinctive, particularly the tripartite apex of the median lobe formed by the ventral margin, dorsal margin, and ostial plate (Fig. 30 C), which is unique among Anillinus species east of the Appalachians.   
Description.  
 Habitus ABL = 1.81–1.85 mm. Integument Dorsal microsculpture effaced from most of forebody, present only medially on vertex and weakly impressed on frons and extreme margins of pronotum. Head HW / PW = 0.73–0.74. Frontoclypeal horn well-developed. Three pairs of supraorbital setae present, posterior outer pair smaller than other two. Pronotum Form variable, either convex and smoothly polished, or subdepressed and with microsculpture along margins. Relatively short (PL / ABL = 0.22–0.23) and broad (PW / EW = 0.82–0.85), sides evenly convergent behind middle, moderately constricted basally (PbW / PW = 0.74–0.77). Elytra Slightly ovoid, convex, broad (EW / ABL = 0.35–0.36), with large umbilicate punctures. Legs Male protarsi with protarsomeres 1 and 2 expanded and dentate on inner margin, both bearing adhesive setae ventrally. Male profemora unmodified. Male mesotrochanters unmodified. Male metafemora slightly swollen, with patch of coarse papillate microsculpture medially on posterior face. Abdominal ventrites Unmodified in either sex. Male genitalia Ring sclerite large (RL / ABL = 0.35), oval, strongly constricted anteriorly where it forms a curved shelf projecting ventrally. Median lobe (Fig. 30 C) strongly asymmetrical, twisted dorsally from plane of basal lobes and curved to the right side. In right lateral aspect, appearing strongly curved, with the ventral margin somewhat angular and sinuate before apex, with several short setae present in proximal bend. In right dorsolateral view, appearing slightly curved and slightly enlarged distally, dorsal margin well sclerotized and forming a sharp beak apically, ventral margin narrowly expanded, apex small and produced, buttonlike. Left side of median lobe at base with large semicircular excavation that occupies the entire basal section before bend, associated carina distal to excavation short, ending at ostium that is large, occupying most of the left face of the median lobe. Internal sac with complex armature: the flagellum is long, well sclerotized, with long basal projections, obtusely bent medially or evenly curved depending on angle at which it is viewed, apex ending at ostium; a group of large, dark sharp spines is present dorsally at ostium; a large, spade-like ostial plate is present on left ventrolateral face of apex; in dorsal or ventral views, the apex appears tripartite, with the dorsal and ventral margins meeting and the pointed ostial plate projecting between them. Shape of flagellum and other internal sclerites appearing as an indecipherable dark mass in right lateral aspect. Right paramere short and broad, with four apical setae (Fig. 30 B). Left paramere conchoid, with fore preapical pores on ventral face, apical two bearing short setae (Fig. 30 A). Female genitalia Spermatheca long, abruptly enlarged distally, stem bent at a slightly acute angle proximally or evenly curved (Fig. 21 C). Spermathecal duct not apparent in the two specimens examined. Bursa copulatrix with conspicuous sclerotized folds.   
Distribution.  
Known only from a small area of Chestnut Ridge Heritage Preserve in Greenville Co., SC (Fig. 29).  
Sympatry.  
 Members of this species have been collected with A. sp. “ South Carolina, Chestnut Ridge ” and S. dunavani.   
Natural history.  
Most specimens have been collected through Berlese extraction of sifted leaf litter and dead wood. Two specimens were collected from the undersides of rocks.  
Species status justification.  
 The male genitalia are unique within the genus, particularly the complex tripartite apex of the median lobe. DNA sequence data indicate the species is most closely related to A. simplex, A. cornelli and the undescribed species A. sp. “ South Carolina, Chestnut Ridge ”, which all differ from A. castaneus in external structure and male genitalic characters. Anillinus castaneus and “ South Carolina, Chestnut Ridge ” occur in syntopy, providing strong evidence that the two are reproductively isolated.   
Derivation of species name.  
A male adjective, from the Latin for Chestnut, in reference to the color of the mature specimens and the name of the type locality, which itself is presumably named for the American Chestnut tree, once an abundant component of Appalachian forests.  
 Anillinus sp. “ South Carolina, Chestnut Ridge ”   
Figs 24 C, 29, 32 B, E  
 Material examined. USA • South Carolina • 1 ♂; Greenville Co.; Chestnut Ridge Heritage Preserve; 35.15071, - 82.28211; 20 Oct. 2021; C. W. Harden leg.; on underside of embedded rock, alluvial forest near Little Pacolet River; CWH- 401, CUAC 000170069.   
GenBank: OR 853206, OR 839244, OR 839666, OR 837917, OR 838074, OR 838251.  
 Diagnosis. The single specimen, a male (Fig. 32 B), is large (ABL = 1.98 mm) and unusual in having the dorsal microsculpture of the forebody strongly developed in the pattern of the loweae group (present on entire surface except for paramedian patches on vertex) while being an otherwise typical member of the valentinei group, whose members typically have dorsal microsculpture largely absent. The median lobe is typical of the valentinei group, with a long, well-sclerotized flagellum and several well-sclerotized spines lining the internal sac. The proximal curve of the flagellum (Fig. 32 E) is shorter than in A. castaneus (Fig. 32 D).   
 Notes. The data from morphology and DNA sequences both support recognition of this individual as a species distinct from any other in the genus, but we feel more specimens are needed to allow an adequate description. A return trip in March 2022 to search for more specimens was unsuccessful, but the site is readily accessible and the habitat is protected, so it is likely that more individuals can be obtained in the future.
description: Published as part of Harden, Curt W. & Caterino, Michael S., 2024, Systematics and biogeography of Appalachian Anillini, and a taxonomic review of the species of South Carolina (Coleoptera, Carabidae, Trechinae, Anillini), pp. 69-197 in ZooKeys 1209 on pages 69-197, DOI: 10.3897/zookeys.1209.125897