, Volume 678, Issue 1, pp 17–36 | Cite as

Freshwater mussel (Mollusca: Bivalvia: Unionoida) richness and endemism in the ecoregions of Africa and Madagascar based on comprehensive museum sampling

  • Daniel L. GrafEmail author
  • Kevin S. Cummings
Primary Research Paper


The objective of this study was to assess freshwater mussel (Mollusca: Bivalvia: Unionoida) species distributions among the freshwater ecoregions of Africa and Madagascar to discover areas of high richness and endemism. These are among the top criteria for identifying biodiversity hotspots and establishing conservation priorities. Distributions were determined from museum specimens in 17 collections. In total, 5,612 records for 87 unionoid species could each be assigned to one of 90 freshwater ecoregions. The majority of species (55%) are known from only one (34 spp.) or two (14) ecoregions. Only three are known from more than 20 ecoregions: Etheria elliptica (38 ecoregions), Chambardia wahlbergi (25), and Mutela rostrata (21). The most species-rich ecoregions are Lake Victoria Basin (17 spp.), Upper Nile (16), Upper Congo (14), Senegal–Gambia (13), and Sudanic Congo–Oubangi (13). Those with the most endemic species are Lake Tanganyika (8 spp.), Lake Victoria Basin (6), Bangweulu–Mweru (4), and Lake Malawi (3). Twenty-five ecoregions have no known freshwater mussels. These patterns are significantly correlated with fish and general freshwater mollusk richness. Unionoid richness also varies significantly among major habitat types. These patterns are relevant to biogeography and conservation and indicate areas in need of further research. We argue that freshwater mussels are valuable as focal species for conservation assessments, and they themselves merit management consideration for their ecosystem functions and distributions in imperiled habitats. It is recommended that field surveys be conducted to determine the current status of species in all areas of Africa and Madagascar.


Unionidae Iridinidae Etheriidae Margaritiferidae Africa Madagascar Ecoregions 



This research was funded by grants from the National Science Foundation to DLG (DEB-0316125, 0542575) and KSC (DEB-0316488). The authors are grateful to the curators and the collection managers who permitted access to the specimens in their charge, often hosting us for weeks. T.K. Kristensen and Michele Thieme generously provided their unpublished data on mollusk distributions in Africa. Tim Hayes, Katie Vazquez, Jerry Graf, Jeremy Tiemann, and Jonah White assisted with specimen image processing and georeferencing. Bert Van Bocxlaer and an anonymous reviewer provided many useful suggestions and comments that improved this article. The authors express their thanks to all those mentioned above.

Supplementary material

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© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  1. 1.Department of Biological SciencesUniversity of AlabamaTuscaloosaUSA
  2. 2.Illinois Natural History SurveyUniversity of IllinoisChampaignUSA

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