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

Liberonautes schubarti sp. nov.

(figs. 1, 2C, 3C View Fig , 4C, 5C, 6 View Fig K-O, 7G-I)

Material examined.— Sierra Leone. Holotype: adult ♂ (CW 19, CL 13, CH 6.8, FW 6.3 mm), Sugar Loaf Mountain (08°25ļ15.1ļļN 13°13ļ32.2ļļW), near Freetown, Western Area (= Freetown Peninsula), 420 m asl, coll. P. A. Mvogo Ndongo, 13 January 2021 (ZMB Crust. 33106) . Paratypes: 1 subadult ♂ (CW 14.6, CL 10.0, CH 5.5, FW 4.6 mm), adult ♀ (CW 23.2, CL 15.5, CH 8.8, FW 7.6 mm), subadult ♀ (CW 18.9, CL 12.8, CH 7.5, FW 7.3 mm), from forest stream around Guma Lake (08°21ļ44.1ļļN 13°11ļ31.2ļļW), Sugar Loaf Mountain , near Freetown, Western Area, 390 m asl, coll. P. A. Mvogo Ndongo, 30 January 2021 (ZMB Crust. 33107). Non-types: 1 adult ♂ (CW 21.9, CL 14.5, CH 7.6, FW 7.5 mm), 3 adult ♀♀ (CW 19.3, 22.6, 23.1, CL 13.7, 15.5, 15.7, CH 7.7, 8.4, 8.5, FW 6.9, 7.9, 7.1 mm, respectively) (CARC-01), all same data as holotype.

Diagnosis.— Small species, adult at CW 22 mm; postfrontal crest distinct, completely traversing carapace, encountering carapace margin; anterolateral carapace surface with rows of carinae, posterolateral surface smooth ( figs. 3C View Fig , 5C); semicircular, urogastric, cardiac, cervical, transverse branchial carapace grooves faint, obscure ( figs. 3C View Fig , 5C); exorbital tooth low blunt; ( figs. 3C View Fig , 5C); intermediate, epibranchial teeth granular ( figs. 3C View Fig , 5C); surface texture of branchiostegite subhepatic region with carinae; major cheliped dactylus curved leaving long narrow interspace when closed ( figs. 6K View Fig ); G1TA medium length ca. two-fifths as long as G1SA, (G1TA/G1SA = 0.4), G1SA lateral margin gently curved inward (fig. 7G, H).

Description of holotype.— Carapace transversely oval, wide (CW/FW = 3.1), medium high (CH/FW = l.4); front slightly indented, wide (FW/CW = 0.3) (figs. 2C, 3C View Fig ); exorbital tooth low blunt, intermediate epibranchial teeth reduced to granule ( figs. 3C View Fig , 5C); anterolateral carapace surface with rows of carinae, posterolateral surface smooth (figs. 2C, 3C View Fig , 5C); postfrontal crest distinct, completely traversing carapace, encountering carapace margin at epibranchial teeth; carapace lateral margin granulated, curving inward posteriorly, not continuous with posterolateral margin ( fig. 3C View Fig ). Width of posterior margin of carapace subequal to FW. Carapace branchiostegite divided into 3 regions by longitudinal, vertical sulci (figs. 4C, 5C). Longitudinal sulcus beginning at respiratory opening, curving backward dividing suborbital, subhepatic regions from pterygostomial region (figs. 4C, 5C); vertical sulcus curved, meeting epibranchial tooth, dividing suborbital from subhepatic regions (figs. 4C, 5C). Suborbital, pterygostomial regions smooth, subhepatic region with carinae (fig. 4C). Vertical sulcus on carapace branchiostegal wall curving backward to meet anterolateral margin at epibranchial tooth, dividing suborbital from subhepatic regions (fig. 4C).

Mandibular palp comprising basis plus two endopod articles; terminal article with small hardened ridge on superior margin near junction between articles ( fig. 6N 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. 4C, 5C, 6O View Fig ).

Thoracic sternal sulcus Sl/2 short, distinct, S2/3 deep, straight, completely traversing sternum, S3/4 reduced to 2 short notches laterally; episternal sulci S4/E4-S6/E6 clearly visible; S7/E7 obscure (fig. 4C).

Male chelipeds unequal; fingers slim, elongated (figs., 6K, L). Major cheliped dactylus stout, slightly arched, lined by small teeth, leaving long narrow interspace when tips touching; minor chela dactylus straight, cutting edge meeting that of propodus pollex leaving no interspace (figs., 6K); lower margin of propodus of major, minor chelae almost straight lacking curved indentation ( fig. 6L View Fig ). Cheliped inferior margins of merus lined by granules, distal tooth low, blunt; merus superior surface with rows of carinae ( fig. 6M View Fig ). Cheliped carpus inner margin with large, broad pointed distal tooth, proximal tooth small, followed by granule ( fig. 6M View Fig ). Walking legs P2-5 robust, P3 longest, P5 shortest; dactyli P2-5 with downward-pointing short stiff setae; P5 dactylus short (fig. 2C).

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

G1TA stout, curved, medium length, ca. two-fifths as long as G2SA (G1TA/ G1SA = 0.4), G1SA broadest basally, tapering gently, lateral margin gently curved inward, (fig. 7G, H); G2TA long, ca. two thirds of G2TA length (G2TA/G2SA = 0.6), flagellum-like (fig. 7I).

Colour in life.— Anterolateral carapace surfaces black, posterolateral carapace surfaces, chelipeds, walking legs P2-5 all red (fig. 2C).

Etymology.— This species is named to honour our late colleague and friend Prof. Dr Christoph Schubart who passed away in March 2023 during a field trip with his students to Jamaica. His many achievements include numerous contributions to the field of freshwater crab biology from around the world, including Africa. The specific name thus is a noun in the genitive singular.

Habitat.— Liberonautes schubarti sp. nov. lives in mountain streams (420 asl) draining Sugar Loaf Mountain, and in lowland streams and forest wetlands in Guma Lake lower down (254 asl) on Sugar Loaf Mountain. This species is also found in sandy soil, in burrows and forested wetlands adjacent to the streams; therefore, this species probably has a semi-terrestrial lifestyle.

Distribution.— Known only from Sugarloaf Mountain near Freetown, Western Area, Sierra Leone (fig. 1).