Mussel of the

Page last updated
4 June 2020

Mussel of the Month

The February 2008 Mussel of the Month is Solenaia soleniformis. Solenaia is a genus of five species from throughout the Indotropics.

[Since February 2008 when this species was selected as Mussel of the Month, S. soleniformis has been moved to the genus Balwantia. — DLG]

Solenaia soleniformis
BMNH 1904.12.30.200. Cachar [India]. H. Harvey, Esq.!

elongate  shellsSolenaia is found throughout southeastern Asia, from India-Burma and Indochina, north to the Yangtze. A new species, S. khwaenoiensis was recently described from Thailand, and perhaps the diversity of this genus will grow as new areas are explored.

Solenaia soleniformis, as the name suggests, resembles the marine bivalve Solen. This elongate, edentulate morphology has arisen multiple times within the Unionoida, and this convergent shell morphology has historically caused some confusion in the taxonomic literature. However, while the shells of these lineages may have a similar appearance, when the soft-parts are available, there can be no confusing members of different these different families. In fact, for the most part, the family to which these genera belong can be determined from the shell alone, once one is familiar with the conchological synapomorphies of the different groups.

It does become difficult to infer anything about relationships among the southeast Asian unionids with elongate shells lacking robust hinge teeth. We expect that as molecular characters are added to the growing morphological database, some of these mysteries will be unraveled.

The adaptive advantages of various shell shapes have been discussed by Savazzi & Peiyi and Watters.


Phylum Mollusca
Class Bivalvia
Subclass Palaeoheterodonta
Order Unionoida

Superfamily UNIONOIDEA Rafinesque, 1820

Family UNIONIDAE s.s.

Genus Solenaia Conrad, 1869

Species Solenaia soleniformis (Benson, 1836)

For more information about Solenaia and the functional morphology of freshwater mussel shells, check out:
  • Savazzi, E. & Y. Peiyi. 1992. Some morphological adaptations in freshwater bivalves. Lethaia 25: 195-209.
  • Watters, G.T. 1994. Form and function of unionoidean shell sculpture and shape (Bivalvia). American Malacological Bulletin 11: 1-20.
  • Deein et al. 2006. A new species of Solenaia from Thailand (Bivalvia: Unionidae: Ambleminae). Natural History Journal of Chulalongkorn University 3: 53-58.
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