Redescription of Potamonautes sidneyi (Rathbun, 1904) (Decapoda, Potamonautidae) and description of a new congeneric species from KwaZulu-Natal, South Africa

Abstract

A new species of freshwater crab, Potamonautes danielsi sp. n., is described from the southern region of the KwaZulu-Natal Province, South Africa. Potamonautes danielsi most closely resembles Potamonautes sidneyi which is re-described here, but can be distinguished by a suite of key morphological characters including carapace shape and width, slim pereopods, inflated propodi of the chelipeds, and the shape and terminal segment length:subterminal segment length ratio of the 1st gonopod. In a previous study (Gouws et al. 2015), a 9.2–11.8 % divergence was found in the mitochondrial COI and 16S genes of the Potamonautes sidneyi clade, allowing for the delineation of a new species. Despite the clear molecular distinction between the two species, it is difficult to separate them based on individual morphological characters, as there is a great deal of overlap even among key features. The new species is found in slow-moving mountain streams and pools at high altitudes between Umhlanga and Mtamvuna, in KwaZulu-Natal.

Phylogeographic structure and continued surveys of a Vulnerable South African freshwater crab (Potamonautidae, Potamonautes lividus): Implications for the IUCN Red Listing of the Afrotropical fauna

“…Nevertheless, decapod diversity and alpha taxonomy in the Afrotropical region remain relatively poorly documented, considering that large areas have not been surveyed for decades owing to civil war, conflict, and general inaccessibility. Despite these drawbacks, there has recently been a steady and concerted effort to document freshwater crab diversity in the Afrotropical region, resulting in the description of a new genus and several species new to science, many of which are narrow endemic species (Cumberlidge & Daniels, 2014; Cumberlidge et al, 2019; Daniels, 2017; Daniels et al, 2019; Mvogo Ndongo et al, 2019; Peer et al, 2017; Peer et al, 2015; Phiri & Daniels, 2013; Wood & Daniels, 2016). Within the Afrotropical region, 28% of the 94 freshwater crabs assessed by Cumberlidge et al (2009) fall into one of the three major threatened groups: 14 species are Vulnerable (VU), 10 are Endangered (EN), and two are Critically Endangered (CR).…”

“…In southern Africa, a region that has been relatively well surveyed and in which the alpha taxonomy of freshwater crabs is well established, recent surveys of previously neglected habitat, such as forests, wetlands, and mountainous regions, have resulted in the description of 14 species, most of which are characterized by very restricted distribution ranges (Cumberlidge et al, 2016; Daniels, 2017; Daniels et al, 2019; Daniels & Bayliss, 2012; Daniels et al, 2014; Peer et al, 2015; Peer et al, 2017; Phiri & Daniels, 2013, 2014; Wood & Daniels, 2016). The IUCN Red Listing of the southern African freshwater crab fauna lists a single species, Potamonautes lividus , as VU (Cumberlidge & Daniels, 2008).…”

“…Historically, P. lividus was known from only three localities (University of Zululand campus and Mdibi and Mapelane nature reserves) in north‐eastern KwaZulu‐Natal province (Gouws & Stewart, 2001; Gouws et al, 2001). Some museum specimens that superficially resemble P. lividus , such as specimens from False Bay Park in the iSimangaliso Wetlands Park, have subsequently been described as a new species (Peer et al, 2015), and an additional three forest‐dwelling freshwater crab species have been described subsequently from KwaZulu‐Natal (Cumberlidge et al, 2019; Peer et al, 2017). Recent surveys of the IOCB forest freshwater systems in both KwaZulu‐Natal and the neighbouring Eastern Cape province have revealed the presence of several new distribution records for P. lividus (S.R.…”

Phylogeographic relationships of Freshwter Crabs, Potamonautes Macleay, 1838 (Decapoda Potamonautidae), in Central Kenya in relation to similar species in southern Africa highlands

“…For example, haplotype network analysis (Fig. 2) showed that Potamonautes stocks in Western Rift Valley and Southern Tanzania are presumably the geneological link between Kenya derived populations and those from Malawi and Southern Africa (Peer et al, 2017). Ribosomal DNA sequence data obtained in this study (Figs.…”

“…This classification identified three species: P. jeanneli (Bouvier, 1921) and P. odhneri (Colosi, 1924) that originally were synonymous, while P. alluaudi (Bouvier, 1921) is recognized as a valid species rather than as a subspecies of P. suprasulcatus (Hilgendorf, 1898). Related classification studies (Peer et al, 2017) on freshwater crabs in mountain streams in Kwa-Zulu highlands (South Africa) using cytochrome oxidase I gene and 16S ribosomal genes re-defined P. danielsi Peer, Gouws, Lazo-Wasem, Perissinotto et Miranda, 2017 as a separate species from the clade of closely related P. sidneyi (Rathbun, 1904) (Gouws et al, 2015). These studies highlight difficulties in taxonomic separation of closely related individuals based on morphological characters and the relevance of augmenting classification using molecular analysis.…”