Lost species in Cameroon: rediscovery of the endangered freshwater crab, <br />Louisea balssi (Bott, 1959) (Brachyura: Potamonautidae), with notes on its ecology and conservation

Abstract

The rare and endangered Cameroonian potamonautid freshwater crab, Louisea balssi (Bott, 1959), was recently rediscovered after not having been seen for the last 109 years and presumed extinct. The new specimens of L. balssi were collected from the Southwest Region of Cameroon, about 80 km from the type locality, and include the first adult male to be recorded for this species. A redescription of L. balssi, which includes for the first time the adult characters of the male gonopods and chelipeds, is provided. New data on the habitat, population structure, and distribution of this species are also provided. Threats to the species and the implications to its conservation are discussed.

Taxonomic revision of the endemic Cameroonian freshwater crab genus Louisea Cumberlidge, 1994 (Crustacea, Decapoda, Brachyura, Potamonautidae), with descriptions of two new species from Nkongsamba and Yabassi

“…1). Louisea edeaensis is known from Yaounde, Edea, and the Lake Ossa faunal reserve, while L. balssi is known from the Bakossi region at Barombi Mbo near Kumba and from Manengouba Ecological Reserve (Cumberlidge 1994, 1999, Mvogo Ndongo et al 2017a, 2018. Louisea nkongsamba sp.…”

“…Diagnosis. Amended from Cumberlidge (1994Cumberlidge ( , 1999; Mvogo Ndongo et al (2018). Carapace smooth, urogastric groove faint; postfrontal crest faint, complete, meeting anterolateral margin behind intermediate tooth (Fig.…”

“…Redescription. A re-description of L. balssi is given in Mvogo Ndongo et al (2018). Additional character state descriptions are added here in the light of the new material to further distinguish between L. balssi and its congeners.…”

“…The morphological features of L. balssi are mainly defined from the adult male specimens collected from Mt. Manengouba (Mvogo Ndongo et al 2018). The only available specimens from Kumba are sub-adults whose gonopod, sternal, and cheliped characters are not fully developed, which makes them less useful for taxonomic studies (Cumberlidge 1999).…”

“…However, our recent biotic surveys in Cameroon (in August 2015 and May 2017) have led to the rediscovery of L. edeaensis from lowland forests below 400 m asl (Bedimet Island of the Lake Ossa wetland complex), and of L. balssi from high altitude forests above 1300 m asl (Mt. Manengouba) (Mvogo Ndongo et al 2017a, 2018. The molecular data from the fresh specimens established the validity of the genus Louisea, and enabled the resolution of longstanding questions surrounding the phylogenetic relationships of the Louisea that was definitively assigned to the subfamily Potamonautinae Bott, 1970(Mvogo Ndongo et al 2017c.…”