This small species is distinctive in having a thick, amygdaloid-shaped (almond-shaped) shell with a very strong hinge and strong shell sculpture of distinct rugose ridges and wrinkles. There is a posterior wing with a prominent ridge. The beaks are heavily sculptured with 'V’ shaped ridges and that sculpture extends onto the adult shell. Colour on outer surface olive to dark brown. Inside valves bluish, stained brown around the beaks. The shell reaches 40 mm in length and the height/length ration is 55-60%.
This species is separated from Hyridella (Hyridella) on the basis of its distinctive shell sculpture but is otherwise like Hyridella (Hyridella) in other shell features and general anatomy. McMichael & Hiscock (1958) noted that this species has prominent siphons of equal size, the exhalant siphon being brick red, inhalant being darker with three rows of internal papillae. The marsupium occupies the middle third of the inner demibranch in females.
Hyridella glenelgensis (Dennant,1898)
Class Bivalvia
Infraclass Heteroconchia
Cohort Palaeoheterodonta
Order Unionida
Superfamily Unionoidea
Family Hyriidae
Subfamily Hyriinae
Genus Hyridella Swainson, 1840
Original name: Unio glenelgensis Dennant, 1898. In Dennant, J. (1898). Description of a new species of Unio from the River Glenelg. Proceedings of the Royal Society of Victoria 10: 112-113.
Type locality: Roseneath, Glenelg River, Victoria.
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 silty sand/mud in streams and rivers. Suspension feeder. Larvae (glochidia) are brooded in the gills of females and, when released, become parasitic on fish gills before dropping to the sediment as young mussels.
Glenelg and Wannon Rivers of western Victoria. One old record in the Australian Museum from Port Fairy, Victoria, collected in the late 1800s, was presumably obtained from the now degraded Moyne River.
This species is listed as Critically Endangered (CR) on the IUCN Red List and under the Commonwealth of Australia Environment Conservation and Biodiversity Protection Act 1999 and the Victorian Flora and Fauna Guarantee Act 1988.
Graf, D. L. & Cummings, K. S. (2019). Hyriidae Swainson, 1840. Pp. 214-217 in C. Lydeard & Cummings, K. S. Freshwater Mollusks of the World: a Distribution Atlas. Baltimore, John Hopkins University Press.
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.
Iredale, T. (1934). The freshwater mussels of Australia. Australian Zoologist 8: 57-78 pls 3-6.
Iredale, T. (1943). A basic list of the fresh water Mollusca of Australia. Australian Zoologist 10: 188-230.
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. & 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.
Playford, T. J. & Walker, K. F. (2008). Status of the endangered Glenelg River Mussel Hyridella glenelgensis (Unionoida: Hyriidae) in Australia. Aquatic Conservation: Marine and Freshwater Ecosystems 18: 679-691.
Raadik, T. A. (2019). Recovery actions for Glenelg Freshwater Mussel: Biodiversity On-ground Actions. Regional Partnerships and Targeted Actions Project 2017–2018. The State of Victoria Department of Environment, Land, Water and Planning.
Raadik, T. A., Stoessel, D. J., Ryan, S. & Murphy, N. (2021). Locating the threatened Glenelg Freshwater Mussel in the lower Glenelg River system 1. Remote sensing and physical sampling. Arthur Rylah Institute for Environmental Research Technical Report Series, Heidelberg, Victoria.
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.
Threatened Species Scientific Committee (TSSC) (2011). Commonwealth Listing Advice on Hyridella glenelgensis (Glenelg Freshwater Mussel). Department of Sustainability, Environment, Water, Population and Communities. Canberra, ACT: Department of Sustainability, Environment, Water, Population and Communities. Available from: http://www.environment.gov.au/biodiversity/threatened/species/pubs/82953-listing-advice.pdf. In effect under the EPBC Act from 16-Feb-2011.
Treby, S. (2016) Building mussels: Determining causes of relative abundance in two sympatric freshwater mussels (Bivalvia, Hyriidae, Hyridella) in southeastern Australia. BSc (Hons) Thesis, La Trobe University, Victoria.
Victorian Department of Sustainability and Environment (Vic. DSE) (2009t). Draft Flora and Fauna Guarantee Action Statement-Glenelg Freshwater Mussel Hyridella glenelgensis. Available from: http://www.dse.vic.gov.au/CA256F310024B628/0/267883776C8F91C2CA25764F0013FC14/$File/Glenelg+Freshwater+Mussel+july+2009.pdf.
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.
Walker, KF, Jones, H. A. & Klunzinger, M. 2014. Hyridella glenelgensis. The IUCN Red List of Threatened Species 2014: e.T58609631A58628791. http://dx.doi.org/10.2305/IUCN.UK.2014-3.RLTS.T58609631A58628791.en
