Velesunio wilsonii (Lea, 1859)

Diagnostic features

This species is compressed and rather elongate for the genus (height/length ratio <53%). Shell length up to 125 mm; tapered posteriorly, not winged or very slightly winged; ventral margin slightly rounded in juveniles, straight in adults. The anterior muscle scars are moderately impressed, and the hinge teeth are smooth. Siphons are lightly pigmented (cf. Velesunio angasi).

Classification

Velesunio wilsonii (Lea, 1859)

Common name: Wilson's mussel

Class Bivalvia

Infraclass Heteroconchia

Cohort Palaeoheterodonta

Order Unionida

Superfamily Unionoidea

Family Hyriidae

Subfamily Velesunioninae

Genus Velesunio Iredale, 1934

Original name: Unio wilsonii Lea, 1859. In Lea, I. (1859). Descriptions of twenty one new species of exotic Unionidae. Proceedings of the Academy of Natural Sciences of Philalphia 11: 151-154.

Type locality: Issac River, Queensland.

Synonyms: Unio (Alasmodon) stuarti A. Adams & Angas, 1864; Centralhyria wilsonii caurina Iredale, 1934.

State of taxonomy

The last major taxonomic revision of Australian freshwater mussels was by McMichael & Hiscock (1958).

Based on the available molecular results, Walker et al. (2014) pointed out that a re-assessment of Australian hyriids is needed.

Biology and ecology

Shallow burrower in silty sand/mud in streams, billabongs, and slow-flowing rivers. Suspension feeder. Larvae (glochidia) are brooded in the marsupia of the gills of females and, when released, become parasitic on the gills or fins of fish where they likely undergo metamorphosis before dropping to the sediment as free-living juvenile mussels. May be able to tolerate low oxygen concentrations and long periods out of water.

Distribution

Lakes, streams and rivers of coastal Queensland between the Mary River and Cairns; most of inland Queensland; western Gulf of Carpentaria and Murray-Darling basin extending into NSW; SE inland Northern Territory; NE South Australia and the Kimberley region of Western Australia.

Further reading

Allan, J. K. (1934). Pearl from a freshwater mussel, and notes on the occurrence of pearls. The Victorian Naturalist 51: 166-169.

Baker, A. M., Bartlett, C., Bunn, S. E., Goudkamp, K., Sheldon, F. & Hughes, J. M. (2003). Cryptic species and morphological plasticity in longlived bivalves (Unionoida: Hyriidae) from inland Australia. Molecular Ecology 12:2707–2717.

Baker A. M, Sheldon F, Somerville, J., Walker, K. F. & Hughes J. M. (2004). Mitochondrial DNA phylogenetic structuring suggests similarity between two morphologically plastic genera of Australian freshwater mussels (Unionoida: Hyriidae) Molecular Phylogenetics and Evolution 32: 902–912.

Feary, S. (1981). The potential of freshwater mussels as seasonal indicators in archaeology. BA(Hons) thesis, Dept Prehistory and Anthropology, Australian National University, Canberra.  

Haas, F. (1969). Superfamilia Unionacea. Das Terreich, 88 (1-10), 1-663.

Hughes, J. M., Baker A. M,  Bartlett, C,  Bunn, S. E, Goudkamp, K. & Somerville, J., 2004. Past and present patterns of connectivity among populations of four cryptic species of freshwater mussels Velesunio spp.(Hyriidae) in central Australia. Molecular Ecology 13, 3197–3212.

Iredale, T. (1934). The freshwater mussels of Australia. Australian Zoologist 8: 57-78.

Iredale, T. (1943). A basic list of the fresh water Mollusca of Australia. Australian Zoologist 10: 188-230.

Klunzinger M.W., Morgan D. L., Lymbery A. J., Ebner B. C., Beatty S. J. & Thomson G.L. (2010) Discovery of a host fish for glochidia of Velesunio angasi (Sowerby, 1867) (Bivalvia: Unionoida: Hyriidae) from the Fortescue River, Pilbara, Western Australia Australian Journal of Zoology 58: 263-266.

Lamprell, K. & Healy, J. (1998). Bivalves of Australia, volume 2. Leiden, Backhuys Publishers.

McMichael, D. F. & Hiscock, I. D. (1958). A monograph of the freshwater mussels (Mollusca: Pelecypoda) of the Australian region. Australian Journal of Marine and Freshwater Research 9: 372-508.

Sheldon, F. & Walker, K. F. (1989). Effects of hypoxia on oxygen consumption by two species of freshwater mussel (Unionacea: Hyriidae) from the River Murray [Australia]. Australian Journal of Marine and Freshwater Research 40: 491-499.

Simpson, K. N. G. & Blackwood, R. (1973). An Aboriginal cache of freshwater mussels at Lake Victoria, NSW. Memoirs of the National Museum of Victoria 34: 217-218.

Smith, B. J. (1992). Non-marine Mollusca. Pp. i-xii, 1-408 in W. W. K. Houston. Zoological Catalogue of Australia, 8. Canberra, Australian Government Publishing Service.

Walker, K. F. (1981). The distribution of freshwater mussels (Mollusca: Pelecypoda) in the Australian zoogeographic region. Pp. 1233-1249 in A. Keast. Ecological Biogeography of Australia. The Hague, Dr W. Junk.

Walker, K. F. (2004). A guide to the provisional identification of the freshwater mussels (Unionoida) of Australasia. Albury, Murray Darling Freshwater Research Centre.

Walker, K. F., Byrne, M., Hickey, C. W. & Roper, D. S. (2001). Freshwater Mussels (Hyriidae) of Australasia. Pp. 5-31 in G. Bauer & Wächtler, K. Ecology and Evolution of the Freshwater Mussels Unionoida. Ecological Studies. Berlin, Springer-Verlag.

Walker, K. F., Jones, H. A. &  Klunzinger, M. W. (2014). Bivalves in a bottleneck: taxonomy, phylogeography and conservation of freshwater mussels (Bivalvia: Unionoida) in Australasia. Hydrobiologia 735:61–79.

Wirtado, T. H. 1994. Aspects of the biology of Velesunio ambiguus Philippi from a tropical freshwater environment, Ross River, Townsville, Australia. Master of Tropical Science thesis, Department of Zoology, James Cook University of North Queensland.  

Zieritz, A., Sartori, A. F. & Klunzinger, M. W. (2013). Morphological evidence shows that not all Velesunioninae have smooth umbos. Journal of Molluscan Studies 79: 277–282.