Nesonautes Cumberlidge & Daniels 2022, GEN. NOV.
Creators: name: Cumberlidge, Neil
name: Daniels, Savel R.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Potamonautidae
Nesonautes

description: GENUS NESONAUTES GEN. NOV.
(FIGS 1B 2, 4G–I, 9C; TABLES 1–3)
Zoobank registration: urn:lsid:zoobank.org:act: 558E16D5-0F1C-45CE-A1AE-F1F2438C5758.
Thelphusa A. Milne-Edwards, 1869: 185, pl. 9, fig. 4, fig. 4a–b; Greef, 1882: 37; 1884: 54; A. Milne-Edwards, 1886: 150; 1887: 130; Ozorio, 1887: 221; 1889: 129, 132; 1892: 199; 1905: 149.
Telphusa Brito-Capello, 1871: pl. 2, fig. 12 [not A. Milne-Edwards].
Potamon (Potamonautes) Ortmann, 1897: 304, 308; Rathbun, 1900: 283; 1904: pl. 14, fig. 10; 1905: 168–169; De Man, 1914: 135.
Potamon Chace, 1942: 216.
Potamonautes (Platypotamonautes) Bott, 1955: 229, 235, pl. XXX: figs la–d, 11 (only Po. (Pl.) margaritarius = N. margaritarius comb. nov.; not Po. (Pl.) ecorssei = Occidensonautes ecorssei comb. nov., Po. (Pl.) platynotus = Arcopotamonautes platynotus comb. nov., Po. (Pl.) pilosus = Rotundopotamonautes pilosus comb. nov., Potamonautes (Rotundopotamonautes) neumanni = Rotundopotamonautes neumanni comb. nov.
Potamonautes margaritarius Balss, 1914: 102; Ng et al., 2008: 171; Cumberlidge, 2008: 72, 77, tab. 1; 2011: 79, 82–83, tabs 6.1, 6.3; Daniels & Klaus, 2018: 119–127, figs 1–3, tab 1; Cumberlidge & Daniels, 2018: 289–295, figs 1–3.
Diagnosis: G1 TA long (TA/SA 0.45–0.48 length of G1 SA); G1 TA angled at 45° to the longitudinal axis of G1 SA; G1 TA widened in the middle (dorsal fold higher than ventral fold); G1 TA terminating in highly upcurved tip (Fig. 4G –I); carapace flattened (CH /FW 1.0); anterolateral margin behind epibranchial tooth either finely toothed or granular; third maxilliped ischium smooth, lacking vertical suture.
Etymology: The genus name is a combination of the Greek νήσος, island, and ναύτες seamen, “- nautes ” being a common suffix for freshwater crabs. This to recognize that this genus of freshwater crabs is endemic to São Tomé Island. The gender is masculine.
Type species: Thelphusa margaritaria A. Milne- Edwards, 1869, by present designation.
Species included: Nesonautes margaritarius (A. Milne- Edwards, 1869) comb. nov. and Nesonautes saotome (Cumberlidge & Daniels, 2018) comb. nov.
Distribution: Nesonautes species are endemic to São Tomé Island (São Tomé and Príncipe) (Daniels & Klaus, 2018; Cumberlidge & Daniels, 2018; Fig. 9C).
Remarks: Nesonautes is established here to accommodate two species of freshwater crabs that are endemic to São Tomé Island, which were previously considered to be species of Potamonautes s.l. (Bott, 1955; Cumberlidge & Daniels, 2018). A new genus is necessary because these two species form a unique genetic lineage separate from the large clade for Potamonautini (Fig. 1B 3) and the clade formed by Erimetopus, Longipotamonautes and Occidensonautes (Daniels & Klaus, 2018). Because neither of the included species is the type species of a genus or a subgenus, a new genus name is provided here.
Bott (1955) included N. margaritarius (as P. margaritarius) as one of five species in his subgenus Potamonautes (Platypotamonautes) (together with Potamonautes ecorssei, Potamonautes platynotus, Potamonautes pilosus and Potamonautes neumanni). However, subgenus P. (Platypotamonautes) is not monophyletic because the species he included were found here to belong to four different phylogenetic lineages (Daniels et al., 2006, 2015; Fig. 1) and it is therefore not recognized here. Potamonautes margaritarius i s t h u s a s s i g n e d t o N e s o n a u t e s, P. e c o rs s e i i s transferred to Occidensonautes. Potamonautes platynotus is moved here to Arcopotamonautes and P. pilosus and P. neumanni are now assigned to Rotundopotamonautes.
description: Published as part of 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, pp. 1268-1311 in Zoological Journal of the Linnean Society 194 (4) on pages 1291-1292, DOI: 10.1093/zoolinnean/zlab082, http://zenodo.org/record/6461478