Ligidium protuberans, Recuero & Caterino, 2025

Ligidium protuberans sp. nov.

urn:lsid:zoobank.org:act:65FAB813-B5FB-4865-9F36-925FC2C1DCA2

Figs 6–7 View Fig View Fig

Ligidium sp. 3 – Recuero & Caterino 2024: table 1.

Diagnosis

This new species is characterized by a male pleopod 2 endopodite distally broadened, with rounded tip presenting a short, squarish projection on its distal margin. It also can be identified from all other Appalachian species based on molecular data, representing a distinct evolutionary lineage.

Etymology

From the latin ‘ protubero ’, meaning ‘protuberance’, referring to the characteristic projection in the male pleopod 2 endopodite.

Material examined

Holotype

USA – North Carolina • ♂; Swain Co., Great Smoky Mountains N.P., Payne Creek at Lakeshore Trail ; 35.4855° N, 83.8028° W; 553 m a.s.l.; 12 Apr. 2022; M. Caterino, E. Recuero, A. Haberski and P. Wooden leg.; GenBank no: OR169915 (Cox1); USNM, CUAC000171349 About CUAC .

GoogleMaps

Paratypes GoogleMaps

USA – South Carolina • 1 ♂; Pickens Co., Chimney Top Gap; 35.0644° N, 82.7953° W; 781 m a.s.l.; 23 Mar. 2023; C.W. Harden leg.; CUAC000177090 About CUAC • 1 ♀; same data as for preceding; CUAC000177089 About CUAC • 1 ovi ♀; same data as for preceding; CUAC000177088 About CUAC .

Other material examined

USA – North Carolina • 2 ♀♀; Macon Co., Nantahala N.F., Van Hook Glade Campground ; 35.0783° N, 83.245° W; 1006 m a.s.l.: 21 Apr. 2022; S. Payne leg.; CUAC000171316 About CUAC , CUAC000171317 About CUAC GoogleMaps • 1 ♀; Clay Co., Nantahala N.F., Tusquitee Bald ; 35.1467° N, 83.7146° W; 1262 m a.s.l.; 1 Sep. 2020; M. Caterino and F. Etzler leg.; CUAC000138058 About CUAC GoogleMaps .

Description

Body length of males 6.3–6.5 mm, of females 6.8–8.6 mm; width (at pereonite 4) of males 2.8–3, of females 3.3–4.6 mm. Color in ethanol ( Fig. 6 View Fig ) dorsally marbled brown and white, with a conspicuous dark brown longitudinal medial stripe running from pereonite 1 to pereonite 7; caudal margin of pereonites with no defined dark brown bands; epimera brown with large white spots in the outer surface an at the base; pleonites brown to dark brown with conspicuous white spots; telson with two large white spots laterally, and a white anchor-shaped spot caudally; head marbled brown and white, white above the eyes; antennae brown with white spots in basal segments and a white setae bundle in the flagellum; uropod brown with iner part of basipodite white; pereopods brown and white, pleopods mostly white. Antennule ( Fig. 7G View Fig ) three-segmented; first segment about 1.4 times as long as wide, 3 spiniform setae on its distal border; second segment about 2.5 times as long as wide, also bearing 3 strong spiniform setae on the distal border; third segment with blunt apex and a single seta. Antennae ( Fig. 7F View Fig ) with 5 segmented peduncle, relative size of antennomeres 5>4>3>2>1; antennal flagellum with 11–13 articles. Dactylus of pereopods with outer claw longer than inner one; no sexual dimorphism observed in pereopods 1 ( Fig. 7H View Fig ) and 7 ( Fig. 7I View Fig ). Male pleopod 1 endopodite ( Fig. 7A View Fig ) with obtuse triangular projection, bearing 2–3 strong, blunt setae, up to 1.5 times as long as endopodite; caudal and inner margins with pilose setae. Pleopod 1 exopodite ( Fig. 7B View Fig ) with broadly rounded caudal margin bearing 3–4 strong, blunt setae, 0.7–0.9 times as long as exopodite. Male pleopod 2 exopodite ( Fig. 7C View Fig ) 2 times as wide as long; inner and most part of frontal margin with dense, hairy setation, as in outer caudal corner; caudal margin with 5–6 short but strong setae. Male pleopod 2 endopodite ( Fig. 7D–E View Fig ) distally broadened, with rounded tip presenting a row of small denticles in the inner corner and a short, squarish terminal projection in the distal margin; inner margin with minute spiniform setae, larger and more conspicuous at base. Telson ( Fig. 6 View Fig ) with caudal margin obtusely produced. Uropod ( Fig. 7J View Fig ) with endopodite 1.3–1.4 times as long as exopodite when not broken, and about 2 times as long as basipodite.

Distribution

The species has been found scattered in the southern Blue Ridge Mountains ( Fig. 6 View Fig ), at low to midaltitudes. All studied specimens have been collected in leaf litter from hardwood forests.

Remarks

Ligidium protuberans sp. nov. corresponds with Ligidium sp. 3 in Recuero & Caterino (2024a). This species is closely related to L. enotahensis sp. nov. and L. schultzi sp. nov. ( Fig. 1A View Fig ), but it can be easily diagnosed from them by the conspicuous short projection present in the male pleopod 2 endopodite. All three gene fragments analyzed are informative to identify this species, with high interspecific p-distances for Cox1, and low to medium in the conserved NaK and 28S fragments (Supp. file 1), forming a reciprocally monophyletic clade in all cases.