Mussel of the

Page last updated
6 November 2020

Mussel of the Month

The November 2020 Mussel of the Month is Atlanticoncha ochracea. Atlanticoncha is a monotypic genus on the Atlantic Slope of North America.

MCZ 178838. Schuylkill River, near Philadelphia, Pennsylvania (neotype).

Train your spell-checkers — we have another new freshwater mussel genus: Atlanticoncha. New genera have been the theme of systematic mussel research for the last couple years. Fortunately, the story behind this one is short and clear.

Unio ochraceus was described by Say in 1817 in the first work ever by an American malacologist. Jump to a more modern era, and Simpson (1900) called it Lampsilis ochracea at a time when the name Lampsilis was even more inclusive than it is today. That name stuck almost all the way through the 1980s (Williams et al., 1993) until the species got moved to Leptodea. And, there it stayed for a long time. Doug Smith (2000) made a case for Ligumia that didn’t gain any traction.

We have been using Leptodea ochracea for three decades, but we had never bothered to do a phylogenetic analysis. When Chase Smith et al. (2019, 2020) did actually look into where L. ochracea fits among the Lampsilini, they recovered it on its own branch and gave it the new name, Atlanticoncha ochracea.


Phylum Mollusca
Class Bivalvia
Subclass Palaeoheterodonta
Order Unionoida

Superfamily UNIONOIDEA Rafinesque, 1820
Family UNIONIDAE s.s.
Subfamily AMBLEMINAE Rafinesque, 1820
Tribe LAMPSILINI Ihering, 1901

Genus Atlanticoncha Smith, Pfeiffer & Johnson, 2020

Species Atlanticoncha ochracea (Say, 1817)

To find out more about Altanticoncha and American freshwater mussels, check out:
  • Say, T. 1817. Article "Conchology." in W. Nicholson (ed.). American Edition of the British Encyclopedia or Dictionary of Arts and Sciences, Comprising an Accurate and Popular View of the Present Improved State of Human Knowledge. First Edition. Samuel A. Mitchell and Horace Ames, Philadelphia, Pennsylvania. Vol. 2 + 4 plates. No pagination.
  • Simpson, C.T. 1900. Synopsis of the naiades, or pearly fresh-water mussels. Proceedings of the United States National Museum 22: 501-1044.
  • Smith, C.H., N.A. Johnson, K. Inoue, R.D. Doyle & C.R. Randklev. 2019. Integrative taxonomy reveals a new species of freshwater mussel, Potamilus streckersoni sp. nov. (Bivalvia: Unionidae): implications for conservation and management. Systematics and Biodiversity 17(4): 331-348.
  • Smith, C.H., J.M. Pfeiffer & N.A. Johnson. 2020. Comparative phylogenomics reveal complex evolution of life history strategies in a clade of bivalves with parasitic larvae (Bivalvia: Unionoida: Ambleminae). Cladistics 36: 505-520.
  • Smith, D.G.. 2000. On the taxonomic placement of Unio ochraceus Say, 1817 in the genus Ligumia (Bivalvia: Unionidae). Nautilus 114(4): 155-160.
  • Williams, J.D., M.L. Warren, K.S. Cummings, J.L. Harris & R.J. Neves. 1993. Conservation status of freshwater mussels of the United States and Canada. Fisheries 18(9): 6-22.
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