This species can be identified by its oblong-ovate rather inflated shell which is strongly ridged posteriorly and has heavy v-shaped sculpture restricted to the umbos which are raised above the dorsal margin. Its periostracum is distinctive in being glossy purple-black in colour with very fine, faint impressed sculpture. It reaches about 90 mm in length, and the height/length ratio is about 60%. Glochidia small (length 70-75 μm) with widely-spread, forked bicuspid teeth.
Hyridella australis (Lamarck, 1819)
Common name: Southern freshwater mussel, Nepean mussel, Austral mussel
Class Bivalvia
Infraclass Heteroconchia
Cohort Palaeoheterodonta
Order Unionida
Superfamily Unionoidea
Family Hyriidae
Subfamily Hyriinae
Genus Hyridella Swainson, 1840
Original name: Unio australis Lamarck, 1819. In Lamarck, J.B.P.A. (1819). Histoire Naturelle des Animaux sans Vertèbres. Paris : J.B.P. Lamarck Vol. 6 (1) 2nd Edn, 343 pp.
Type locality: Nepean River, New South Wales
Synonyms: Unio dorsuosus Gould, 1850; Unio napeanensis Conrad, 1850; Unio lessoni Küster, 1856. Propehyridella nepeanensis opportuna Iredale, 1934; Propehyridella nepeanensis novata Iredale, 1943.
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 reassessment of Australian hyriids is needed and one is now in progress.
Shallow burrower in fine, compact sand/mud in streams and rivers, preferring quieter conditions (such as slack waters along stream edges) compared with other species of Hyridella (Jones 2013). Suspension feeder. Larvae (glochidia) are brooded in the marsupia of the gills of females and, when released attached to fish gills where they undergo metamorphosis before dropping to the sediment as free-living juvenile mussels.
Coastal rivers and streams of southeast Queensland, New South Wales, and eastern Victoria.
Ian Hiscock published papers on the biology of supposedly this species, but they were actually based on Velesunio ambiguus (see under that species for details).
Beesley, P. L., Ross, G. J. B. & Wells, A., Eds. (1998). Mollusca: The Southern Synthesis. Parts A & B. Melbourne, CSIRO Publishing.
Chamani, P. M., Wadige, M., Taylor, A. M., Maher, W. A., Ubrihien, R. P. & Krikowa, F. (2014). Effects of lead-spiked sediments on freshwater bivalve, Hyridella australis: linking organism metal exposure-dose-response. Aquatic Toxicology 149: 83-93.
Cotton, B.C. & Gabriel, C.J. (1932). Australian Unionidae. Proceedings of the Royal Society of Victoria (ns) 44: 155-160.
Haas, F. (1912). Die Unioniden. pp. 113-136 in Küster, H.C., Martini, F.W. & Chemnitz, J.H. (eds) Systematiches Conchylien-Cabinet. Nürnberg: Bauer & Raspe Bd 9 Abt. 2.
Iredale, T. (1934). The freshwater mussels of Australia. Australian Zoologist 8: 57-78 pls 3-6.
Jeffree, R. A., Markich, S. J. & Brown, P. L. (1993). Comparative accumulation of alkaline-earth metals by two freshwater mussel species from the Nepean River, Australia: consistencies and a resolved paradox. Marine and Freshwater Research 44: 609-634.
Jones, H. A. (2013). Landscape scale impacts on freshwater mussel (Unionoida: Hyriidae) distribution and status in southeastern Australia. PhD thesis, University of Sydney, New South Wales.
Jones, H. A. & Byrne, M. (2014). Changes in the distributions of freshwater mussels (Unionoida: Hyriidae) in coastal southeastern Australia and implications for their conservation status. Aquatic Conservation: Marine and Freshwater Ecosystems 24: 203-217.
Jones, H. A., Simpson, R. D. & Humphrey, C. L. (1986). The reproductive cycles and glochidia of fresh-water mussels (Bivalvia: Hyriidae) of the Macleay River, Northern New South Wales, Australia. Malacologia 27: 185-202.
Klunzinger, M. W., Jones, H.A., Humphrey, C. L., Melchior, M., Raadik, T.A., Treby, S., Chandler, L. & Sheldon, F. (2023). Comparative diversity in glochidia of Australasian freshwater mussels. Frontiers in Environmental Science 12: 1305077.
Lamprell, K. & Healy, J. (1998). Bivalves of Australia, volume 2. Leiden, Backhuys Publishers.
McMichael, D. F. (1955). The Identity and Validity of Hyridella australis (Lamarck) 1819. The Nautilus 69: 6-13.
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 + 319 plates.
Ryan, S., Bacher, G. J. & Martin, A. A. (1972). The mussel Hyridella australis as a biological monitor of the pesticide endrin in fresh water. Search 3: 446-447.
Shea, M. 1995. Freshwater molluscs of Sydney. Australian Shell News 88:4- 6.
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.
Smith, B. J. & Kershaw, R. C. (1979). Field guide to the non-marine Molluscs of South-eastern Australia. Canberra, A.N.U. Press.
Wadige, C. P. M., Taylor, A. M., Maher, W. A., Ubrihien, R. P. & Krikowa, F. (2014). Effects of lead-spiked sediments on freshwater bivalve, Hyridella australis: linking organism metal exposure-dose-response. Aquatic Toxicology 149: 83-93.
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., 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.
