Longipotamonautes, (BOTT, 1955)

Cumberlidge, Neil & Daniels, Savel R., 2022, A new multilocus phylogeny reveals overlooked diversity in African freshwater crabs (Brachyura: Potamoidea): a major revision with new higher taxa and genera, Zoological Journal of the Linnean Society 194 (4), pp. 1268-1311 : 1291

GENUS LONGIPOTAMONAUTES ( BOTT, 1955) STAT. NOV.

( FIGS 1B 2 , 4D–F, 9B; TABLES 1–3 )

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Thelphusa A. Milne-Edwards, 1886: 149 ; 1887: 132, pl. 7: fig. 2, fig. 2a.

Potamon De Man, 1898: 436 ; Chace, 1942: 206.

Potamon (Potamonautes) Rathbun, 1900: 284 .

Potamon (Potamon) Rathbun, 1904: 296 , pl. 12, fig. 9; 1921: 419–422, pl. 27, 28, figs 1, 10.

Potamonautes (Longipotamonautes) Bott, 1955: 244–245 , pl. 7: fig. 2a–d, figs 23, 73; Coulter, 1991: 256.

Potamonautes Balss, 1936: 174–177 , figs 9, 12, 13; Ng et al., 2008: 171; Cumberlidge, 2008: 72, 77, tab. 1; 2011: 79, 82–83, tabs 6.1, 6.3.

Diagnosis: Epibranchial tooth large, pointed, directed forward; third maxilliped ischium smooth, lacking vertical sulcus; S3/4 incomplete, missing except for deep notches on lateral ends; G1 TA medium long (TA length 0.33 × SA length), tubular, with parallel sides, medial and lateral folds low ( Fig. 4A–B ); telson bell-shaped with lateral margins indented; pleon broadly triangular, sides, base subequal. Major chela propodus lower margin longer than carapace width; dactylus slim, highly arched; G1 TA tip broad with hook ( Fig. 4D–F ); anterolateral margin between exorbital tooth, epibranchial tooth with variable number of large pointed teeth.

Type species: Thelphusa ballayi A. Milne-Edwards, 1886 , by original designation.

Species included: Longipotamonautes acristatus ( Bott, 1955) comb. nov., Longipotamonautes adentatus ( Bott, 1955) comb. nov., Longipotamonautes ballayi (A. Milne- Edwards, 1886) comb. nov., Longipotamonautes nheenae ( Cumberlidge, 2017a) comb. nov., L. paecilei (A. Milne- Edwards, 1886)comb.nov., Longipotamonautespunctatus ( Bott, 1955) comb. nov., Longipotamonautes reidi (Cumberlidge, 1999) comb. nov., Longipotamonautes schubotzi ( Balss,1936) comb.nov. and Longipotamonautes semilunaris ( Bott, 1955) comb. nov.

Distribution: Lo. acristatus, Lo. adentatus , Lo. ballayi , Lo. paecilei and Lo. punctatus are all found in the D.R. Congo, Lo. schubotzi is found in the Central African Republic, Lo. reidi is found in Nigeria and Cameroon and Lo. nheenae is endemic to Gabon ( Balss, 1936; Bott, 1955; Cumberlidge, 1999, 2017a; Cumberlidge & Boyko, 2000; Cumberlidge & Reed, 2004; Fig. 9B ).

R e m a r k s: S u b g e n u s P o t a m o n a u t e s ( Longipotamonautes ) Bott, 1955 is given genus rank and is re-described here. Bott (1955) established Potamonautes (Longipotamonautes) with Thelphusa ballayi A. Milne-Edwards, 1886 as the type species and included four species and two subspecies in this subgenus. Longipotamonautes is established here to accommodate seven species of freshwater crabs from the Lower Congo Basin in Central Africa that were previously considered to be species of Potamonautes s.l. All six taxa that Bott (1955) assigned to Po. ( Longipotamonautes ) are transferred here to Longipotamonautes , with the addition of Lo. nheenae from Gabon and Lo. reidi from Nigeria and Cameroon. Unfortunately, DNA data are only available for one of these species, Lo. ballayi . The phylogeny presented here ( Fig. 1 ) together with those of Daniels & Klaus (2018: fig 1) and Wood et al. (2019: fig. 1) consistently recovered Lo. ballayi as part of a well-defined clade ( Fig. 1B 2 ) that is sister to the branch represented by Erimetopus , and separate from the clades of Maritimonautini ( Fig. 1B1 ) and Potamonautini ( Fig. 1B 3 ). The other species are included in Longipotamonautes based on shared morphological characters that conform to the above generic diagnosis.

Figures

Figure 1. A, maximum clade credibility tree of the Afrotropical freshwater crab fauna based on four DNA loci with support values (posterior probabilities and bootstrap values of the ML analyses) with a geological timescale below the tree topology. Posterior probabilities> 0.95 pP (*above branch) and bootstrap values> 75% (* below branch) were regarded as statistically supported and are shown on the tree topology. Clade A, Liberonautinae, clade B, Potamonautinae, clade B1, Maritimonautini, clade B2, Erimetopini, clade B3, Potamonautini. B, detail of the maximum clade credibility tree of the Afrotropical freshwater crab fauna showing Clade B3 Potamonautini with the species included in the five genera within the tribe: Arcopotamonautes (B3[1]), Lirrangopotamonautes (B3[2]), Platythelphusa (B3[3]), Potamonautes s.s. (B3[4]) and Rotundopotamonautes (B3[5]).

Figure 3. Gonopods 1 and 2 of four genera in Liberonautinae. A–C, Buea asylos (Cumberlidge et al., 2019: fig. 7a, d; 8a); D–F, Potamonemus mambilorum (Cumberlidge et al., 2019: fig. 7b, e; 8b); G–I, Sudanonautes floweri; J–L, Louisea balssi (Mvogo Ndongo et al., 2018: fig. 5a–c, © Magnolia Press, reproduced with permission from the copyright holder). A, D, G, J, left G1 ventral view; B, E, H, K, left G1 dorsal view; C, F, I, L, left G2 ventral view. Scale bar: A, B, D, E, G, H, J, K = 2.0 mm, C, F, I, L = 1.8 mm.

Figure 4. Gonopods 1 and 2 of the four genera in Erimetopini. A–C, Erimetopus vandenbrandeni; D–F, Longipotamonautes ballayi; G–I, Nesonautes margaritarius; J–L, Occidensonautes ecorssei. Scale bar: A–L = 2.0 mm.

Figure 9. Maps showing the distributional ranges of the four genera of Erimetopini (A) Erimetopus, (B) Longipotamonautes, (C) Nesonautes and (D) Occidensonautes.

Figure 2. Liberonautinae. Gonopods 1 and 2 of Liberonautes latidactylus, NMU9.V.2005B (CW 72, CL 47.2, CH 20.5, FW 19.3 mm) Guinea, West Africa. A, left G1 ventral view; (B) left G1 dorsal view; (C) left G2 ventral view. Scale bar: A, B = 2.8 mm, C = 1.8 mm.