Mussel of the Month

Chambardia moutai is one of the poorly studied iridinid species from Africa. It was originally described as a subspecies of the widespread Chambardia wahlbergi from Angola. Since then, it had been mostly ignored — except to be synonymized with C. wahlbergi wahlbergi by Daget (1998) — until we recognized it as a valid species (Graf & Cummings, 2006). It has only been mentioned a handful of times since (e.g., Graf & Cummings, 2011).

We didn’t and don’t have any DNA to back up our taxonomic revision of Chambardia in Angola. It was just based on old fashioned conchological taxonomy and biogeography: an easily distinguished shell-shape limited to one river (the Cunene). That Chambardia wahlbergi, which is found from nearly everywhere else in Africa, never approaches that form elsewhere was good enough for us.

Even with the recent explosion in the use of DNA for “molecular taxonomy” many freshwater mussels from tropical Africa and South America are still under-sampled for nucleotides. The table below reports the numbers of Genbank accessions for COI and 28S by freshwater mussel subfamily.* The generally species-poor subfamilies of the global south (Etheriidae, Mycetopodidae, Iridinidae, and Hyriidae) are represented by dozens of DNA sequences, whereas hundreds or thousands of accessions are attributed to some subfamilies of the Unionidae.

So far the subfamilies of the Iridinidae and Mycetopodidae have barely figured into molecular phylogenetic analysis — although the same COI and 28S have been repeatedly reanalyzed as outgroups to the Unionidae (shown on the Etherioidea cladomics page). But, modernization of the taxonomy of tropical species needs to move forward regardless to support the conservation of these mollusks.

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* These tallies of COI and 28S only refer to those sequences reported in the molecular phylogenetic studies sampled to-date for the Cladomics data on this website.