Liberonautes sugarloaf, Mvogo Ndongo & von Rintelen & Clark & Cumberlidge, 2024

Mvogo Ndongo, Pierre A., von Rintelen, Thomas, Clark, Paul F. & Cumberlidge, Neil, 2024, Morphological and molecular evidence support four new Liberonautes Bott, 1955 (Decapoda, Potamonautidae, Liberonautinae) species of freshwater crabs from Sierra Leone, West Africa, Crustaceana 97, pp. 709-731 : 723-725

publication ID	https://doi.org/10.1163/15685403-bja10410
DOI	https://doi.org/10.5281/zenodo.15090647
persistent identifier	https://treatment.plazi.org/id/A76C879A-FFE4-416C-FE05-26659622FC1F
treatment provided by	Valdenar (2025-03-26 15:20:05, last updated 2025-03-26 17:11:35)
scientific name	Liberonautes sugarloaf
status	sp. nov.

Treatment

Liberonautes sugarloaf sp. nov.

(figs. 1, 2D, 3D View Fig , 4D, 5D, 6 View Fig P-T, 7J-L)

Material examined.— Sierra Leone. Holotype: adult ♂ (CW 60.0, CL 39.0, CH 21.0, FW 17.0 mm), Sugar Loaf Mountain , (08°25ļ15.1ļļN 13°13ļ32.2ļļW), Freetown , Western Area (= Freetown Peninsula), 420 m asl, coll. P. A. Mvogo Ndongo, 13 January 2021, (ZMB Crust. 33367). Paratypes: adult ♂ (CW 51.0, CL 34.3, CH 19.3, FW 15.0 mm), adult ♀ (CW 46.7, CL 31.6, CH 18.1, FW 14.0 mm), 3 adult ♀♀ (CW 42.4, 47.3, 48.9, CL 29.3, 31.9, 34.0, CH 16.0, 17.50, 19.3, FW 14.5, 13,5, 12.6 mm, respectively), Sugar Loaf Mountain, (08°25ļ27.8ļļN 13°13ļ26.5ļļW), Freetown , Western Area (= Freetown Peninsula), 382 m asl, coll. P. A. Mvogo Ndongo, 13 January 2021 (CARC-05). Non-types: adult ♂ (CW 66.1, CL 44.2, CH 26.1, FW 19.4 mm), adult ♀ (CW 75.0, CL 51.0, CH 32.0, FW 21.3 mm), grounds of British High Commission, (08°28ļ19.3ļļN 13°16ļ15.6ļļW), Freetown , Western Area (= Freetown Peninsula), 116 m asl, coll. P. A. Mvogo Ndongo,13 January 2021 (CARC-06); 7 subadult ♂♂ (CW 39.0, 41.9, 42.0, 42.0, 42.5, 44.6, 45.5, CL 28.2, 29.6, 29.8, 29.7, 30.3, 32.0, 32.5, CH 15.3, 16.4, 16.7, 16.5, 19.2, 17.0, 17.3, FW 11.6, 12.0, 12.5, 12.2, 13.7, 13.6, 13.3 mm, respectively), 3 subadult ♀♀ (CW 37.6, 43.1, 44.9, CL 27.01, 31.0, 31.3, CH 14.3, 16.6, 16.8, FW 12.1, 12.5, 13.4 mm, respectively), River Moa, Tiwai Island Wildlife Sanctuary (07°32ļ38.87ļļN 11°20ļ55.61ļļW), Eastern Province , 150 m asl, coll. P. A. Mvogo Ndongo, 20 January 2021 (CARC-07).

Diagnosis.— Large species, adult between CW 51-75 mm; postfrontal crest distinct, completely traversing carapace, ends encounter carapace margin; anterolateral, posterolateral carapace surfaces smooth (figs. 2D, 3D View Fig , 5D); semicircular, urogastric, cardiac, cervical, transverse branchial carapace grooves all deep, distinct (figs. 2D, 3D View Fig , 5D); exorbital tooth medium-sized; (figs. 2D, 3D View Fig , 5D); intermediate tooth medium sized, epibranchial tooth granular (figs. 2D, 3D View Fig , 5D); surface texture of branchiostegite subhepatic region smooth; major cheliped dactylus slightly curved leaving long narrow interspace when closed ( fig. 6P View Fig ). G1TA length long, one half as long as G1SA (G1TA/G1SA = 0.5), G1SA lateral margin distinctly curved inward (fig. 7J, K).

Description of holotype.— Carapace transversely oval, wide (CW/FW = 3.3, n = 18), moderately high (CH/FW = l.3, n = 18); front slightly indented, wide (FW/CW = 0.3) (figs. 2D, 3D View Fig ); postfrontal crest distinct, completely traversing carapace, encountering carapace anterolateral margin between intermediate, epibranchial teeth; mid-groove between raised epigastric crests short, deep (figs. 2D, 3D View Fig , 5D); cervical, branchial, cardiac, intestinal, urogastric grooves all distinct, deep (figs. 2D, 3D View Fig , 5D); carapace lateral margin granulated, continuous with posterolateral margin (figs. 2D, 3D View Fig , 5D). Width of posterior margin of carapace subequal to FW. Carapace branchiostegite dividing into 3 regions by longitudinal, vertical sulci (figs. 4D, 5D). Longitudinal sulcus beginning at respiratory opening, curving backward dividing suborbital, subhepatic regions from pterygostomial region (figs. 4D, 5D); vertical sulcus curved, meeting epibranchial tooth, dividing suborbital from subhepatic regions (figs. 4D, 5D). Suborbital, pterygostomial regions smooth, subhepatic region with small granular ridges (carinae) (figs. 4D, 5D). Vertical sulcus on carapace branchiostegal wall curving backward to meet anterolateral margin at epibranchial tooth, dividing suborbital from subhepatic regions (figs. 4D, 5D).

Mandibular palp comprising basis plus two endopod articles; terminal article with small hardened ridge on superior margin near junction between articles ( fig. 6S View Fig ). Third maxillipeds filling entire buccal cavern except for transversely oval efferent respiratory openings at superior lateral corners; exopod with well-developed flagellum; ischium with distinct vertical sulcus (figs. 4D, 5D, 6T View Fig ). Thoracic sternal sulcus S2/3, deep, horizontal, ends not meeting side margins, S3/4 reduced to 2 short notches on margins, obscure in middle; episternal sulci S4/E4- S6/E6 clearly visible, S7/E7 not visible (fig. 4D).

Male chelipeds unequal; fingers slim, elongated ( fig. 6P, Q View Fig ). Major cheliped dactylus stout, slightly arched, lined by small teeth, with three prominent pointed teeth (one proximal, one middle, one distal), propodus with large fused tooth with 4 cusps proximally, followed by smaller teeth interspersed by large tooth distally ( fig. 6P View Fig ). Cheliped inferior margins of merus lined by granules, distal tooth distinct, superior surface with rows carinae ( fig. 6R View Fig ). Cheliped carpus inner margin with distal tooth large, pointed, proximal tooth small, granular ( fig. 6R View Fig ). Walking legs P2-5 robust, P3 longest, P5 shortest; dactyli P2-5 with downward-pointing short stiff setae; P5 dactylus short (fig. 2D).

Male pleon broadly triangular with straight margins. Pleomeres PLl-6 with telson forming slim tapering triangle with indented sides, rounded distal margin; PL3 broadest (fig. 4D).

G1TA slim, curved, needle-like; length long, ca. one half as long as G1SA (G1TA/G1SA = 0.5), G1SA broadest basally, then tapering sharply, distal two-thirds stout, columnar, lateral margin distinctly curve inward (fig. 7J, K); G2TA long, ca. half-length of G2TA (G2TA/G2SA = 0.5), flagellum-like (fig. 7L).

Colour in life.— Dorsal carapace, pereiopods dark brown (fig. 2D).

Etymology.— The new species is named for Sugarloaf Mountain, Western Area, near Freetown, Sierra Leone. The species name sugarloaf is a noun in apposition.

Habitat.— Liberonautes sugarloaf sp. nov. inhabits Sugarloaf Mountain streams and the River Moa at Tiwai Island Wildlife Sanctuary. In both localities, the crab was found living in the water, also under large rocks.

Distribution.— Known from Sugar Loaf Mountain, near Freetown, Western Area, and the wildlife sanctuary in the Upper Guinea forest zone on Tiwai Island, Southern Province, Sierra Leone (fig. 1).

Figures

Fig. 3. The four new species Liberonautes from Sierra Leone, carapace, dorsal view. A, L. kasonko sp. nov. (ZMB Crust. 33104); B, L. njala sp. nov. (ZMB Crust. 33102); C, L. schubarti sp. nov. (ZMB Crust. 33106); D, L. sugarloaf sp. nov. (ZMB Crust. 33367).

Fig. 6. The four new Liberonautes species from Sierra Leone (all adult male holotypes). Frontal view of right and left chela: A, B, L. kasonko sp. nov. (ZMB Crust. 33104); F, G, L. njala sp. nov. (ZMB Crust. 33102); K, L, L. schubarti sp. nov. (ZMB Crust. 33106); P, Q, L. sugarloaf sp. nov., (ZMB Crust. 33367). Right cheliped merus and carpus: C, L. kasonko sp. nov. (ZMB Crust. 33104); H, L. njala sp. nov. (ZMB Crust. 33102); M, L. schubarti sp. nov. (ZMB Crust. 33106); R, L. sugarloaf sp. nov. (ZMB Crust. 33367). Mandibular palp; D, L. kasonko sp. nov. (ZMB Crust. 33104); I, L. njala sp. nov. (ZMB Crust. 33102); N, L. schubarti sp. nov. (ZMB Crust. 33106); S, L. sugarloaf sp. nov. (ZMB Crust. 33367). Left third maxilliped: E, L. kasonko sp. nov. (ZMB Crust. 33104); J, L. njala sp. nov. (ZMB Crust. 33102); O, L. schubarti sp. nov. (ZMB Crust. 33106); T, L. sugarloaf sp. nov. (ZMB Crust. 33367).