Nore pearl mussel

The Nore pearl mussel (Margaritifera durrovensis) is a critically endangered species of freshwater pearl mussel, an aquatic bivalve mollusc in the family Margaritiferidae.

The species is endemic to Ireland and was first identified by R.A. Phillips in 1926, who later declared it a new species in Volume 18 of the Proceedings of the Malacological Society. This designation was controversial, and the taxonomic status of the Nore pearl mussel remains inconclusive. It is often described as a rare ecophenotype of M. margaritifera. The European Union's Habitats Directive on the conservation of natural habitats and wild fauna placed Margaritifera durrovensis on Annex II and Annex V as a separate taxon.