Maritimonautes, Cumberlidge & Daniels, 2022

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 : 1286-1289

MARITIMONAUTES GEN. NOV.

( FIGS 1B1 , 5A–C , 8B; TABLES 1–3)

Zoobank registration: urn:lsid:zoobank.org:act:29BB5EDB-5AB4-48E5-8B42-AA97939DDA7F

Thelphusa A. Milne-Edwards, 1868: 86 , pl. 20, figs 1–4; 1869: 178; 1887: 146; Pfeffer, 1889: 33.

Telphusa Hilgendorf, 1879: 801 ; 1891: 20; 1898: 16.

Potamon (Potamonautes) Ortmann, 1897: 303 , 305.

Potamon De Man, 1898: 434 , 437; Chace, 1942: 190.

Potamon (Potamonautes) De Man, 1898: 262–270 , 436, fig. 3; Rathbun, 1904: pl. 15, figs 8, 9; 1905: 180, fig. 45; 1933: 258; 1935: 26; Sendler, 1912: 199; Bouvier, 1921: 49; Colosi, 1925: 2; Parisi, 1925: 98; Barnard, 1950: 192, fig. 34 f, g.

Potamonautes Balss, 1929: 348 ; Barnard, 1935: 484; Capart, 1954: 841, fig. 36, 17; Cumberlidge, 1997: 580– 582; 1998: 198, 202–203.

Potamonautes (Obesopotamonautes) Bott, 1955: 257– 259 , pl. XXII, figs 2a–d, 19, 80; Pretzmann, 1977: 238, figs 7–12.

Diagnosis: S3/4 deep, V-shaped, completely traversing sternum (or deep at margins, faint in the middle); outer margins of S4 raised and thickened; third maxilliped ischium lacking vertical suture (or if present faint); anterolateral margin of carapace posterior to epibranchial tooth either smooth or granulated, but lacking teeth; G1 TA short (TA length 0.25 × SA length), slim, either not widened in midsection (or dorsal fold slightly higher than ventral fold), tapering evenly to pointed tip ( Fig. 5A, B ).

Etymology: Maritimonautes is derived from the Latin maritimus, coastal, referring to the coastal plain of East Africa, east of the Rift Valley where this genus is found, and the Greek ναύτες, seamen, a common suffix for African freshwater crabs. Gender masculine.

Type species: Thelphusa obesa A. Milne-Edwards, 1868 , by original designation.

S p e c i e s i n c l u d e d: M a r i t i m o n a u t e s c a l c a r a t u s ( Gordon, 1929) comb. nov., Maritimonautes choloensis ( Chace, 1953) comb. nov., Maritimonautes licoensis (Daniels, Bittencourt-Silva, Muianga, & Bayliss, 2020) comb. nov., Maritimonautes namuliensis ( Daniels & Bayliss, 2012) comb. nov. and Maritimonautes obesus (A. Milne-Edwards, 1868) comb. nov.

Distribution: Maritimonautes is found in the lowlying coastal plains of Somalia, Kenya and Tanzania (plus Zanzibar and Pemba islands), including the north coast of Lake Malawi in Tanzania (Ruvuma, Iringa and Mbeya Provinces), Mounts Inago, Mabu, Namuli and Lico in northern Mozambique, Mount Nyangoni (Manicaland Province) in eastern Zimbabwe and the Kruger National Park in Mpumapanga Province, South Africa ( Chace, 1953; Reed & Cumberlidge, 2004; Daniels & Bayliss, 2012; Daniels et al., 2014, 2020; Fig. 8B ).

Remarks: Maritimonautes is established for five species formerly assigned to Potamonautes s.l. DNA data are available for five of these species that are grouped together in a well-supported clade ( Daniels et al., 2015: fig. 2; Daniels & Klaus, 2018: fig. 1; Wood et al., 2019: fig. 1; Fig. 1B1 ). The most recently-described species of this genus ( M. licoensis ) from Mozambique is included based on morphology and the phylogeny published with the description ( Daniels et al., 2020). Two of the species transferred here to Maritimonautes ( M. calcaratus and M. obesus ) were assigned by Bott (1955) to Potamonnautes (Obesopotamonautes) Bott, 1955. The latter subgenus is not recognized here, because it is not monophyletic: two of its three taxa belong to the new genus Maritimonautes ( Fig. 1B1 ), but the third species, Platythelphusa langi , is positioned in a separate lineage for Platythelphusa ( Fig. 1B 3 [3]).

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 5. Gonopods 1 and 2 of one genus in Maritimonautini and three genera in Potamonautini. A–C, Maritimonautes obesus; D–F, Arcopotamonautes suprasulcatus; G–I, Lirrangopotamonautes dybowskii; J–L, Platythelphusa armata. Scale bar: A, B, G–L = 2.0 mm, C, F = 1.8 mm; D, E = 5.0 mm; L = 6.7 mm.

Figure 8. Maps showing the distributional ranges of (A) Potamonautinae, (B) Maritimonautini, (C) Erimetopini and (D) Potamonautini.