Ligidium enotahensis, Recuero & Caterino, 2025

Ligidium enotahensis sp. nov.

urn:lsid:zoobank.org:act:CF5E1EE6-9001-45DA-9DB2-5DE45CA56D20

Figs 2–3 View Fig View Fig

Ligidium sp. 1 – Recuero & Caterino 2024: table 1.

Diagnosis

Ligidium enotahensis sp. nov. can be diagnosed morphologically based on the shape on the male pleopod 2 endopodite, showing a squarish tip with no excrescence, projection, or notch, and on the very broad male pleopod 1 endopodite projection. It also can be identified from all other Appalachian species based on molecular data, representing a distinct evolutionary lineage.

Etymology

From the Cherokee Enotah, a name of the mountain where the species is described, and the Latin suffix ‘ -ēnsis ’, forming an adjective meaning ‘from Enotah’.

Material examined

Holotype

USA – Georgia • ♂; Towns Co., Brasstown Bald; 34.8763° N, 83.8107° W; 1377 m a.s.l.; 17 Nov. 2020; M. Caterino and A. Haberski leg.; GenBank no: OR172584 (Cox1); USNM, CUAC000138051 About CUAC .

GoogleMaps

Other material examined

USA – Georgia • 3 imm.; same data as for holotype; CUAC000171312 About CUAC to CUAC000171314 About CUAC GoogleMaps .

Description

Body length of holotype 5.3 mm, body width (at pereonite 4) 2.6 mm. Color of holotype in ethanol ( Fig. 2 View Fig ) dorsally brown with large whitish patches on dorsal surface, a dark brown longitudinal medial stripe running from pereonite 1 to telson, epimera dark brown with a large white patch; head, antennae and uropods dark brown, pereopods and pleopods lighter brown. Immatures much lighter and without longitudinal stripe. Antennule ( Fig. 3G View Fig ) three-segmented; first segment about 2 times as long as wide, with 3 strong spiniform setae on its distal border; second segment slender, about 4 times as long as wide, also bearing 3 strong spiniform setae on the distal border; third segment small, with round apex and a single seta. Antennae ( Fig. 3F View Fig ) with 5 segmented peduncle, relative size of antennomeres 5>4>3>2>1; antennal flagellum with 11 articles. Dactylus of pereopods with outer claw longer than inner one; no sexual dimorphism observed in pereopods 1 ( Fig. 3H View Fig ) and 7 ( Fig. 3I View Fig ). Male pleopod 1 endopodite ( Fig. 3A View Fig ) with broad, squarish projection bearing 3 strong, blunt setae, 1.4 times as long as endopodite. Pleopod 1 exopodite ( Fig. 3B View Fig ) with a flat caudal margin bearing 3 strong, blunt setae, 0.7 times as long as exopodite. Male pleopod 2 exopodite ( Fig. 3C View Fig ) 2 times as wide as long; inner and most part of frontal margin with dense, hairy setation, as in outer caudal corner. Male pleopod 2 endopodite ( Fig. 3D–E View Fig ) with squared tip showing a ventral oblique line of small, poorly defined denticles along the interior corner; inner margin with minute spiniform setae, no spines at the base. Telson ( Fig. 2 View Fig ) with caudal margin obtusely produced. Uropod ( Fig. 3J View Fig ) with exopodite broken, endopodite about 1.5 times as long as basipodite; in the examined immatures endopodite 1.5–1.6 times as long as exopodite.

Distribution

The species is so far only known from its type locality, near the southern extreme of the southern Appalachian Mountains ( Fig. 2 View Fig ). All specimens were collected in mixed forest leaf litter samples.

Remarks

Ligidium enotahensis sp. nov. corresponds with Ligidium sp. 1 in Recuero & Caterino (2024a). This new species is closely related to L. protuberans sp. nov. and L. schultzi sp. nov., but they can easily be identified based on the shape of male pleopod 2 endopodite, by lacking the conspicuous projection present in L. protuberans , or the marked notch typical of L. schultzi . Ligidium enotahensis also presents a much broader projection of male pleopod 1 endopodite. All three gene fragments analyzed are informative to identify this species, with high genetic p-distances for Cox1, and low in the conserved NaK and 28S fragments (Supp. file 1), forming a reciprocally monophyletic clade with respect to either of the other two in all cases.