Discovery of Buea bangem Mvogo Ndongo, von Rintelen, Tomedi-Eyango & Cumberlidge, 2020 (Crustacea: Potamoidea: Potamonautidae: Liberonautinae) from Mt. Nlonako Wildlife Reserve, Cameroon.

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Description of one new species of freshwater shrimp of the genus Caridina (Crustacea: Decapoda: Atyidae) from two karst caves of Northern Vietnam.

A new species of atyid freshwater shrimp is described from two caves of Bac Kan Province, Northeast Vietnam, namely Caridina namdat sp. nov. This species can be distinguished from its congeners by a suite of morphological characters such as reduced eyes with short eyestalk, very short and unarmed rostrum, slender second pereiopod, elongated endopod of male first pleopod, and long appendix interna of the male second pleopod. Molecular phylogenetic data from the mitochondrial cytochrome oxidase subunit I (COI) and 16S ribosomal RNA genes also support the distinctiveness of the new species from all other examined species.

Deep into darkness: the first stygobitic species of freshwater shrimp of the genus Caridina (Crustacea: Decapoda: Atyidae) from Northern Vietnam.

The first stygobitic species of atyid freshwater shrimps from Vietnam is described from Cuc Phuong National Park, Northern Vietnam. Caridina thachlam sp. nov. can be distinguished from its congeners by a suite of morphological characters such as strongly reduced eyes without eyestalk, short and almost unarmed rostrum and slender pereiopods. Molecular phylogenetic data from the mitochondrial cytochrome oxidase subunit I (COI) and 16S ribosomal RNA genes also support the distinctiveness of the new species from all other species that we have examined.

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

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.

Morphological and molecular evidence for a new species of freshwater crab of the genus Sudanonautes Bott, 1955 (Brachyura: Potamoidea: Potamonautidae) from Cameroon, with notes on its ecology.

A new species of freshwater crab of the genus Sudanonautes Bott, 1955, is described from the tropical rainforests of Edea and Tiko in southern Cameroon, Central Africa. Sudanonautes tiko n. sp. is recognized by a unique combination of characters of the carapace, thoracic sternum, chelipeds, and male first gonopod, and by distinct mtDNA sequences for two loci (COI and 16S rRNA). A diagnosis, illustrations, and a tree of phylogenetic relationships based on mtDNA sequences are provided, along with a comparison to similar species from the region. Brief notes are provided on the ecology of the new species and of three other species of Sudanonautes collected during this study.

New data on the taxonomy, ecology, and conservation of the rediscovered Louisea edeaensis (Bott, 1969) (Brachyura: Potamoidea: Potamonautidae), an endangered freshwater crab from Cameroon.

The rare and endangered Cameroonian potamonautid freshwater crab Louisea edeaensis (Bott, 1969) was recently rediscovered during a biological inventory of the freshwater decapods of southern Cameroon. The previous record dated back more than 100 years. The new specimens allow an updated diagnosis of the species based on comparisons of important taxonomic characters. Photographs of the carapace, gonopods, third maxillipeds, and chelipeds of the largest adult male specimen from Lake Ossa, Cameroon are provided, as are the first photographs of living specimens. The conservation implications of the new data on habitat, population structure, distribution, and threats for this rare and endangered species are discussed.

Freshwater shrimp-sponge association from an ancient lake.

Shrimp-sponge associations occur frequently in marine ecosystems, serving as model systems for the evolution of eusociality. Here, we describe the first known instance of such association in freshwater from an ancient lake in Indonesia. The shrimp Caridina spongicola forms an exclusive and probably commensal association with a yet undescribed spongillinid sponge. Phylogenetic and ecological data suggest a comparatively recent origin of both taxa. Climatic fluctuations may have facilitated speciation and occasional hybridization of the shrimp species, which is derived from a rock-dwelling ancestor. Their extremely localized occurrence in an increasingly disturbed area makes both taxa a conservation priority.