Velesunio angasi (Sowerby, 1867)
The shell is compressed, relatively elongate, the posterior expanded, usually winged; ventral margin usually straight, rarely convex or slightly sinuate; shell length up to 90 mm; width/length ratio greater than 55%. The siphons are brick red with dark blotches (cf. V. wilsoni). Anterior adductor scar weakly impressed and the hinge teeth are smooth.
Velesunio angasi (Sowerby, 1867)
Common name: Freshwater mussel
Original name: Unio angasi Sowerby,1867. Sowerby, G.B. (1867). Monograph of the genus Unio. Conchologia Iconica 16: plts 55-60.
Type locality: Shangway's River,Northern Territory.
Synonyms: Unio bednalli Tate, 1882; Hyridella (Hyridella) bardwelli Clench, 1934; Aparcthyria hemesa Iredale, 1943; Aparcthyria inspecta Iredale, 1943; Quaesithyria fleckeri Iredale, 1943.
The last major taxonomic revision of Australian freshwater mussels was by McMichael and Hiscock (1958).
Based on the available molecular results, Walker et al. (2014) pointed out that a re-assessment of Australian hyriids is needed.
Shallow burrower in silty sand/mud in streams, billabongs and slow-flowing rivers. Suspension feeder. Reproduction occurs throughout the year. Larvae (glochidia) are brooded in the gills of females and, when released, become parasitic on the gills of fish (see Humphrey and Simpson 1985 for list of species) before dropping to the sediment as young mussels. Able to tolerate low oxygen concentrations and long periods out of water. Recrutment is affected by levels of dissolved oxygen (Humphrey & Simpson 1985). These mussels from 11-35 years and life span is correlated with dissolved oxygen concentrations.
This species is widely distributed, occurring from north-eastern Queensland throughout tropical northern Australia, and extending south to the Pilbara region of Western Australia.
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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.
Bollhöfer, A., Brazier, J., Humphrey, C., Ryan, B., & Esparon, A. (2011). A study of radium bioaccumulation in freshwater mussels, Velesunio angasi, in the Magela Creek catchment, Northern Territory, Australia. Journal of Environmental Radioactivity 102: 964-974.
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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.
Humphrey, C. L. & Simpson, R. D. (1985). The biology and ecology of Velesunio angasi (Bivalvia: Hyriidae) in the Magela Creek, Northern Territory (4 parts) Open File Record 38, Office of the Supervising Scientist for the Alligator Rivers Region, Canberra, 476 p.
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.
Jeffree, R. A. & Simpson, R. D. (1986). An experimental study of the uptake and loss of Ra-226 by the tissue of the tropical freshwater musselVelesunio angasi (Sowerby) under varying Ca and Mg water concentrations. Hydrobiologia 139: 59-80.
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.
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Walker, K. F. (1986). The freshwater mussel Velesunio ambiguus as a biomonitor of heavy metals associated with particulate matter. Pp. 175-185 in B. T. Hart. The Role of Particulate Matter in the Transport and Fate of Pollutants. Melbourne, Australia, Water Studies Centre, Chisolm Institute of Technology.
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.