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Alathyria pertexta pertexta Iredale, 1934

Diagnostic features

A. pertexta differs from the other species of Alathyria in not being more elongate (height/length ratio less than 56%). Two subspecies are recognised with the shell of the typical subspecies differing from A. pertexta wardi in having a less truncate posterior end and a generally stronger hinge as well as lacking a posterior ventral sinuation and in having a marked anterior dorsal excavation. Another subspecies occurs in Papua. Uneroded beaks are sculptured with nodules.

Classification

Alathyria pertexta pertexta Iredale, 1934

Common name: Freshwater mussel

Class Bivalvia

Subclass Heteroconchia

Superorder Palaeoheterodonta

Superfamily Hyrioidea

Family Hyriidae

Subfamily: Velesunioninae

Genus Alathyria Iredale, 1934

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

Type locality: Upper Brisbane River, Queensland.

Synonyms: Unio shuttleworthi Lea, 1856 (non Unio shuttleworthi Küster, 1855). Alathyria morti Iredale, 1943.  

State of taxonomy

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.

Biology and ecology

Shallow burrower in sand or gravel. 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.

Additional information on the biology and ecology of members of this family can be found in Fauna of Australia, vol. 5A, pp. 296-298.

Distribution

Coastal river systems and northern parts of the Darling drainage in mid Queensland and northern New South Wales. Also, in part of the Lake Eyre drainage in Queensland.

Further reading

Beesley, P. L., Ross, G. J. B. & Wells, A., Eds. (1998). Mollusca: The Southern Synthesis. Parts A & B. Melbourne, CSIRO Publishing.

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.

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.

Negri, A. P. & Jones, G. J. (1995). Bioaccumulation of paralytic shellfish poisoning (PSP) toxins from the cyanobacterium Anabaena circinalis by the freshwater mussel Alathyria condola. Toxicon 33: 667-678.

Smith, B. J. & Kershaw, R. C. (1979). Field guide to the non-marine Molluscs of South-eastern Australia. Canberra, A.N.U. Press

Walker, K. F. (1981a). The ecology of freshwater mussels in the River Murray. Australian Water Research Council Technical Papers 63: 1-119.

Walker, K. F. (1981b). 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.

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.