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

Liberonautes kasonko sp. nov.

(figs. 1, 2A, 3A View Fig , 4A, 5A, 6 View Fig A-E, 7A-C)

Material examined.— Sierra Leone. Holotype: adult ♂ (CW 47.2, CL 33.0, CH 20.0, FW 15.0 mm), River Tai , Sangbamba 1 (09°22ļ33.3ļļN 11°47ļ29.5ļļW), Kasonko Chiefdom , Northern Province , 367 m asl, coll. P. A. Mvogo Ndongo, 22 January 2021 (ZMB Crust. 33104). Paratypes: adult ♂ (CW 46.5, CL 32.7, CH 19.3, FW 14.5 mm), subadult ♂ (CW 40.0, CL 28.5, CH 18.0, FW 13.0 mm) (ZMB Crust . 33105). Non-types: adult ♀ (CW 50.0, CL 32.2, CH 20.3, FW 20.0 mm), 7 subadult ♂♂ (CW 18.4, 20.3, 20.4, 22.4, 24.1, 24.6, 26.4, CL 14.0, 15.9, 15.7, 16.5, 18.0, 18.6, 20.0, CH 7.5, 8.3, 8.1, 8.7, 10.0, 10.0, 11.0, FW 6.3, 7.2, 7.2, 7.3, 8.3, 7.7, 8.0 mm, respectively) (CARC-02), all same data as holotype.

Diagnosis.— Medium-sized species, adult at CW 46.5 mm; postfrontal crest distinct, completely traversing carapace, ends encounter carapace margins; anterolateral, posterolateral carapace surfaces with carinae (figs. 2A, 3A View Fig , 5A); semicircular, urogastric, cardiac, cervical, transverse branchial carapace grooves all deep, distinct ( figs. 3A View Fig , 5A); exorbital tooth small, blunt; ( figs. 3A View Fig , 5A); intermediate, epibranchial teeth medium sized ( figs. 3A View Fig , 5A); surface texture of branchiostegite subhepatic region with carinae; major cheliped dactylus slightly curved leaving long narrow interspace when closed ( fig. 6B View Fig ); G1TA length long, ca. half as long as G1SA (G1TA/G1SA = 0.5), G1SA lateral margin distinctly curved inward (fig. 7A, B).

Description of holotype.— Carapace transversely oval, wide (CW/FW = 3.2), moderately high (CH/FW = l.2); front slightly indented, wide (FW/CW = 0.3) (figs. 2A, 3A View Fig ). Carapace surface anterolateral regions with rows of carinae, posterolateral regions smooth; cervical, urogastric, cardiac, grooves deep, semicircular, transverse branchial grooves shallow, faint (figs. 2A, 3A View Fig ). Exorbital tooth low, blunt; epibranchial, intermediate teeth small, distinct; (figs. 2A, 3A View Fig ). Postfrontal crest distinct, completely traversing carapace, lateral ends encounter epibranchial teeth; mid-groove on postfrontal crest short, forked (figs. 2A, 3A View Fig , 5A). Carapace lateral margin raised, marked by row of small granules; lateral margin curving inward over carapace posteriorly, not continuous with posterolateral margin (figs. 2A, 3A View Fig , 5A). Width of posterior margin of carapace subequal to FW. Carapace branchiostegite with longitudinal, vertical sulci dividing it into 3 regions (figs. 4A, 5A). Longitudinal sulcus beginning at respiratory opening, curving backward dividing suborbital, subhepatic regions from pterygostomial region (figs. 4A, 5A); vertical sulcus curved, meeting epibranchial tooth, dividing suborbital from subhepatic regions (figs. 4A, 5A). Suborbital, pterygostomial regions smooth, subhepatic region with small granular ridges (carinae) (figs. 4A, 5A).

Mandibular palp comprising basis plus two endopod articles; terminal article with small hardened ridge on superior margin near junction between articles ( fig. 6D View Fig ). Third maxillipeds filling entire buccal cavern except for transversely oval efferent respiratory openings visible at superior lateral corners; exopod with well-developed slender flagellum; ischium with distinct vertical sulcus (figs. 4A, 5A, 6E 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 visible, S7/E7 obscure (fig. 4A).

Male chelipeds unequal ( fig. 6A, B View Fig ), left chela movable finger (dactylus) highly arched, enclosing oval interspace when closed; cutting edge of dactylus with 3 pointed teeth proximally, large tooth midway, small tooth distally ( fig. 6B View Fig ). Fixed finger (pollex) cutting edge lined by small serrated teeth ( fig. 6B View Fig ). Left chela dactylus, propodus straight, small teeth on cutting edge ( fig. 6B View Fig ). Cheliped merus inferior margins lined by granules; distal meral tooth small, low, superior surface of merus with rows carinae ( fig. 6C View Fig ). Cheliped carpus inner margin distal tooth large, pointed, proximal tooth small, granule-sized ( fig. 6C View Fig ). Walking legs P2-5 robust, P3 longest, P5 shortest; dactyli of P2-5 with small downward-pointing setae, P5 dactylus short (fig. 2A). Male pleon broadly triangular with straight edges (fig. 4A).

(ZMB Crust. 33367).

Male pleon broadly triangular with straight margins (fig. 4A). Pleomeres PLl-6 plus telson triangular, with rounded distal margin, PL3-7 forming slim triangle with indented sides, tapering towards telson, PL3 broadest (fig. 4A).

G1TA long, ca. half as long as G1SA (G1TA/G1SA = 0.5); G1SA broadest basally, then tapering sharply, distal two-thirds stout, columnar, lateral margin distinctly curved inward (fig. 7A, B); G2TA long, ca. half length of G2TA (G2TA/G2SA = 0.5), flagellum-like (fig. 7C).

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

Etymology.— The new species is named for the type locality, Kasonko Chiefdom, Northern Province, Sierra Leone. The species name “kasonko ” is used as a noun in apposition.

Habitat.— Liberonautes kasonko sp. nov. was collected by hand in the River Tai, from rock cracks and under stones.

Distribution.— Known only from the River Tai, Kasonko Chiefdom, Northern Province, Sierra Leone (fig. 1).

(ZMB Crust. 33106); D, L. sugarloaf sp. nov. (ZMB Crust. 33367).