Serranillus monadnock 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
Serranillus
Serranillus monadnock

description: Serranillus monadnock sp. nov.   
Figs 16, 17 C, D, 19 A – E, 20 B  
Type material.  
  Holotype male (NCSU) : point mounted, with genitalia in glycerin in plastic microvial pinned beneath labels. Original labels: “ SCYorkCoKings MtStPklogslit Oct 28. 1989 JF & TADCornell ” “ Serranillus new species ♂ det. C. W. Harden 2021 ” “ [QR Code] NCSU_ENT 00327997 ” “ HOLOTYPE Serranillus monadnock Harden & Caterino 2024 ” [red cardstock].   
 Paratypes (n = 2, NCSU). USA • South Carolina • 1 ♂, 1 ♀; Newberry Co.; Little Mountain; 34.188, - 81.408; 8 Dec. 2007; J. and S. Cornell leg.; sift and berlese litter 20 ” D Pine Stump Hole # 5; NCSU _ ENT 00327998 and NCSU _ ENT 00327999; NCSU.   
Diagnosis.  
 This is the only Serranillus species in which males have a flattened medial section of the second abdominal ventrite with longitudinally stretched microsculpture (Fig. 19 B). The body is large, ABL = 2.82 mm (holotype), 2.79–2.87 mm (paratypes), the elytra and pronotum are broad, the head is relatively small (HW / PW = 0.65–0.70), the pronotum has the posterior angles produced posteriorly (Fig. 19 A), and the median lobe of the aedeagus has a sinuate ventral surface, without ventral carinal shelf, with a large, blunt apex (Fig. 19 E).   
Description.  
 Habitus Large (ABL = 2.79–2.87) and robust (PW / EW = 0.84–0.88, EW / ABL = 0.36–0.38), with relatively small head (HW / PW = 0.65–0.70). Integument Dorsal microsculpture largely absent from surfaces of head, present across entire pronotum. Head Frontoclypeal horn well-developed and prominent. Ocular tubercle present on each side in the form of a short, rounded ridge running from lateral dorsal carina down a short distance laterally (Fig. 20 B). Antennae short, not reaching posterior margin of pronotum when bent backward. Pronotum Broad (PW / EW = 0.84–0.88), margins not sinuate before posterior angles, which are slightly constricted (PbW / PW = 0.69–0.71) and protrude beyond posterior pronotal margin. Elytra Broad (EW / ABL = 0.36–0.38), disc flattened, with traces of five striae. Legs Male protarsomeres 1 and 2 expanded and bearing ventral adhesive setae. Male metatrochanters and posterior face of metafemora with coarse papillate microsculpture, metafemora swollen. Female legs unmodified. Abdominal ventrites Males with second abdominal ventrite with a flattened medial region where the microsculpture cells are stretched longitudinally (irregularly isodiametric elsewhere on abdomen). Males with last abdominal ventrite bearing three denticles on posterior margin, the inner one slightly more prominent than the outer two. Male genitalia Median lobe strongly asymmetrical and slightly twisted dorsally from plane of basal lobes (Fig. 17 C, D). In right lateral aspect, the ventral margin undulating, with deep subapical sinuation before the blunt, rounded apex which is deflected ventrally. Row of short, stout setae present on ventral margin near and within subapical sinuation, visible at 100 × or greater. Left side at base with broad, carinate channel that is interrupted medially by prominent dorsolateral region with two raised lumps; narrowed channel continuing across ventral surface, ending at subapical sinuation. Apex of median lobe in holotype curved to right side, appearing sinuous in dorsal or ventral aspects; apex in paratype straight and bladelike, possibly due to teneral condition of the specimen. Internal sac with thin, curved flagellum visible in right lateral aspect near dorsal margin. Large rolled sclerite present on left side of internal sac, making two coils over itself from left lateral wall of median lobe. Lightly sclerotized, blunt paddle-shaped sclerite extending apically from rolled sclerite, meeting left side before apex. Right paramere minute, bluntly rounded, asetose. Left paramere large, conchoidal, with thickened base. Female genitalia Spermatheca with enlarged base, otherwise similar to that of S. jeanneli (Fig. 21 T). Spermathecal duct long and coiled.   
Distribution.  
Known from two localities in York and Newberry Counties (Fig. 16), both isolated monadnocks in the Piedmont ecoregion, Kings Mountain and Little Mountain.  
Sympatry.  
 Three species of Anillinus occur at Kings Mountain State Park, and may co-occur with this species there. Three female Anillinus were collected from the same sample at Little Mountain, and are either unusually small individuals of Anillinus chandleri Sokolov or an undescribed species. A male A. chandleri was taken from a separate litter sample at the same locality.   
Natural history.  
The Kings Mountain specimen was presumably collected from extraction of sifted litter associated with logs, and the two Little Mountain specimens were collected by extraction of sifted litter from within a pine stump hole.  
Species status justification.  
Members of this species differ from those of the four previously described species in several external characters: pronotum with posterior angles produced posteriorly, males with flattened medial area with stretched microsculpture on second abdominal ventrite. The male genitalia are also unique, especially the relatively large, blunt apex of the median lobe.  
Derivation of species name.  
 Noun in apposition, from “ monadnock ”, a word in the Abenaki language meaning an isolated, abruptly rising mountain or hill, in reference to the two known localities of this species on such features.   
Notes.  
The paratype male from Little Mountain is teneral, paler than both the female from the same collecting event at Little Mountain and the male holotype from Kings Mountain. The shape of the median lobe of the teneral paratype differs slightly from that of the holotype (Fig. 17 C, D). In the paratype, the supabical sinuation on the ventral margin is deeper, and the apex of the median lobe is thinner and not curved to the right. Otherwise, the characters of the median lobe agree in both specimens. The unique medial microsculpture of the second abdominal ventrite is also the same in both males. The differences in the median lobe are either due to the teneral condition of the paratype, or may reflect slight geographic variation.  
 Serranillus sp. “ South Carolina, Coon Branch ”   
Figs 16, 20 A, 25 B  
Material examined.  
 USA • South Carolina • 1 ♀; Oconee Co.; Coon Branch Natural Area; 35.0251, - 83.0053; 2 Oct. 2021; C. W. Harden leg.; On underside of embedded rock, steep north-facing slope; CUAC 000169317, CWH- 400; CUAC.   
GenBank: OR 853116, OR 853403, OR 839367, OR 839665, OR 837916, OR 838073, OR 838250, OR 838133.  
 Diagnosis. In addition to being larger (ABL = 2.70 mm), this female specimen differs from the widespread S. dunavani by the presence of faint microsculpture on the disc of the pronotum and the less ovoid shape of the elytra (Fig. 20 A). The phylogeny based on the genes we sampled places the specimen in a well-supported clade with S. septentrionis Sokolov & Carlton and another potentially undescribed species from the Black Mountains in North Carolina.   
 Distribution. Coon Branch Natural Area, near the Whitewater River in Oconee Co.   
 Sympatry. The specimen was collected with adults of Anillinus murrayae Sokolov & Carlton and two individuals of Anillinus that belong to the sinuaticollis group, discussed below as Anillinus sp. “ South Carolina, Coon Branch ”.   
 Natural history. The specimen was collected in October from the underside of a large embedded rock in fine soil on a steep forested slope above the Whitewater River. Litter samples collected in June 2018, October 2020, and August 2022 did not collect this species, nor did a soilwash sample taken in June 2018.   
 Notes. Without associated males, the identity of this species is uncertain. This female from Coon Branch possibly belongs to one of the undescribed species known from adjacent parts of Georgia and North Carolina that we lack DNA sequence data for. Males of both S. sp. “ Georgia, Rabun Bald sp. 1 ” and S. sp. “ North Carolina, Riley Knob ” possess genitalia similar to S. septentrionis, suggesting they likely belong to the same clade as this Coon Branch female.
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