Ligidium nantahala, Recuero & Caterino, 2025

Ligidium nantahala sp. nov.

urn:lsid:zoobank.org:act:A2CAA049-6BCB-4229-A06D-49F61B36B030

Figs 4–5 View Fig View Fig

Ligidium sp. 2 – Recuero & Caterino 2024: table 1.

Diagnosis

Ligidium nantahala sp. nov. presents a male pleopod 2 endopodite with a robust excrescence occupying the inner part of the tip and projected outwards. The projection of male pleopod 1 endopodite presents a triangular profile. It also can be distinguished from all other Appalachian species based on molecular data, representing a distinct evolutionary lineage with no close relationships among the studied taxa.

Etymology

From the Cherokee Nantahala, the name of the forests where the species lives. A noun in apposition.

Material examined

Holotype

USA – North Carolina • ♂; Clay Co., Nantahala N.F., Chunky Gal Trail ; 35.1471° N, 83.7144° W; 1274 m a.s.l.; 7 Jun. 2021; M. Caterino and E. Recuero leg.; GenBank no: OR169931 (Cox1); USNM, CUAC000180794 About CUAC .

GoogleMaps

Paratype GoogleMaps

USA – North Carolina • 1 ♂; same data as for holotype; CUAC000180793 About CUAC .

Other material examined

USA – North Carolina • 1 imm. ♀; same data as for holotype; CUAC000171282 About CUAC GoogleMaps .

Description

Body length of adult males 4.9–5.5 mm, width (at pereonite 4) 2.4–2.6 mm. Color in ethanol of adult males ( Fig. 4 View Fig ) dorsally marbled brown and white, with a conspicuous dark brown longitudinal medial stripe running from pereonite 1 to pereonite 7 and a transverse dark brown band in the caudal margin of pereonites; epimera dark brown with a large white patch at the base; pleonites dark brown caudally, lighter in the central parts (showing in pleonites 4–5 in dorsal view); telson dark brown with a white anchor-shaped spot; head marbled brown and white; antennae with basal segments white and brown, distally brown with some white marking; uropod brown with a large white spot in the basipodite; pereopods and pleopods white with brown marbling. Immature specimen with the same color pattern but lighter brown. Antennule ( Fig. 5G View Fig ) three-segmented; first segment about 1.6 times as long as wide, 3 spiniform setae on its distal border; second segment about 3 times as long as wide, also bearing 3 strong spiniform setae in the distal border; third segment small, with blunt apex and a single seta. Antennae ( Fig. 5F View Fig ) with 5 segmented peduncle, relative size of antennomeres 5>4>3>2>1; antennal flagellum with 10–11 articles. Dactylus of pereopods with outer claw longer than inner one; no sexual dimorphism observed in pereopods 1 ( Fig. 5H View Fig ) or 7 ( Fig. 5I View Fig ). Male pleopod 1 endopodite ( Fig. 5A View Fig ) with obtuse triangular projection, bearing 2 strong, blunt setae, 0.4–0.8 times as long as endopodite. Pleopod 1 exopodite ( Fig. 5B View Fig ) with rounded caudal margin bearing 2 strong, blunt setae, 0.4–0.6 times as long as exopodite. Male pleopod 2 exopodite ( Fig. 5C View Fig ) 1.6–1.7 times as wide as long; inner and frontal margins with limited pilose setation dense, present also along outer caudal corner; caudal margin markedly convex. Male pleopod 2 endopodite ( Fig. 5D–E View Fig ) with rounded tip and a soft, blunt, robust excrescence occupying most of inner part of tip and projecting outwards; inner margin with minute spiniform setae, no spines at the base. Telson ( Fig. 4 View Fig ) with caudal margin obtusely produced, convex in immature female. Uropod ( Fig. 5J View Fig ) with exopodite and endopodite subequal in length when not broken, 1.5–1.7 times as long as basipodite.

Distribution

The species is so far only known from its type locality ( Fig. 4 View Fig ). All specimens were collected in broadleaf forest leaf litter samples.

Remarks

Ligidium nantahala sp. nov. corresponds with Ligidium sp. 2 in Recuero & Caterino (2024a). It is not closely related to any of the other species studied here ( Fig. 1A View Fig ). Morphologically, the presence of a projecting excrescenceat the tip of male pleopod 2 endopodite resembles that observed in L. blueridgensis , L. pacolet sp. nov. and L. whiteoak sp. nov. However, the disposition of the excrescence is different in all four species. In L. nantahala it covers the whole inner part of the tip ventrally, and projects outwards. In L. blueridgensis the excrescence is more slender, and projects from the inner tip corner rising near the margin dorsally, and projecting caudally and inwards. Ligidium pacolet has also a more slender excrescence rising medially or near the inner corner from the end of the tip, projecting caudally or inwards. In L. whiteoak , the excrescence is broad, almost as much as the endopodite stem, rising dorsally and medially from the caudal margin of the tip and projecting caudally and slightly outwards. Ligidium nantahala differs also in the triangular shape of male pleopod 1 endopodite projection, squarish in the other mentioned species. All three gene fragments analyzed are informative to identify this species, with high genetic p-distances for Cox1 and even for the conserved NaK and 28S fragments (Supp. file 1), forming a monophyletic clade in all cases.