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Lortiella opertanea Ponder & Bayer, 2004

Diagnostic features

Shell relatively elongate and narrowly hatchet shaped with the posterior end flaring, anterior end from umbo relatively short, margin rounded. Posterior end relatively long and almost truncate but rounded, ventral margin straight to concave. Dark olive brown, bluish to yellowish to dull golden brown internally. This species is not as narrowly elongate as L. rugata and is more elongate and compressed than L. froggatti. As in all species of the genus, in young specimens the beaks and shell surface lack distinct sculpture.


Lortiella opertanea Ponder & Bayer, 2004

Class Bivalvia

Subclass Heteroconchia

Superorder Palaeoheterodonta

Order Unionida

Superfamily Unionoidea

Family Hyriidae

Subfamily: Velesunioninae

Genus Lortiella Iredale,1934

Original name: Lortiella opertanea Ponder & Bayer, 2004. Ponder, W.F. & Bayer, M. (2004). A new species of Lortiella (Mollusca: Bivalvia: Unionoidea: Hyriidae) from northern Australia. Molluscan Research 24: 89-102.

Type locality: Katherine River, below Gorge (In pool alongside river, under logs and stones), Northern Territory, Australia.

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

Found living beneath large flat rocks in pools in the river bed, where it generally lives on its side with the posterior end towards the outer edge of the stone.


Known only from the Katherine, Douglas and Daly Rivers, Northern Territory and the Carson/King Edward River system (vicinity of Kalumburu), Western Australia.

Further reading

Klunzinger, M. W., Jones, H. A., Keleher, J., & Morgan, D. L. (2013). A new record of Lortiella froggatti Iredale, 1934 (Bivalvia: Unionoida: Hyriidae) from the Pilbara region, Western Australia, with notes on anatomy and geographic range.Records of the Western Australian Museum 28: 1-6.

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. 

Ponder, W. F. & Bayer, M. (2004). A new species of Lortiella (Mollusca: Bivalvia: Unionoidea: Hyriidae) from northern Australia. Molluscan Research 24: 89-102.

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.