Australia: The Land Where Time Began

A biography of the Australian continent 

Jurassic Fish Faunas of Australia

Early and Middle Jurassic

In the Clarence-Moreton Basin the records of actinopterygians are sparsely distributed. In the Walloon Coal Measures, Middle Jurassic deposits, 7 semionotiform specimens, that were fragmentary, have been found (Grant-Mackie, 2000). A deposit near Monto in the Mulgildie Basin has also produced a partial body outline of a semionotid fish, that authors¹ believe is a Lepidotes sp., (Thies & Turner, 2001). This specimen is preserved in dark sandstone rich in iron that the authors¹ presume represents the Hutton Sandstone, the unit underlying the Walloon Coal Measures. The specimen  was associated with ?Osmundacaulis specimens, the presence of which also suggests an age of Middle Jurassic.

The bony fish genus Lepidotes, Agassiz, 1832, that inhabited both fresh and marine waters, lakes and shallow seas, is related to modern gars. Some species grew to  more than 2 m long and had a covering of thick scales that were enameled. Their batteries of teeth were rounded and peg-like, suiting them to a diet of molluscs that required the crushing of shells. During the Jurassic-Cretaceous such semionotiform fish had a cosmopolitan distribution (Thies, 1989; Olsen & McClune, 1991). They have the potential to allow the development of a  marine-to-continental-scale correlation scheme, and a taxonomic review to this end is underway for the Jurassic (Turner, 2008).

Late Jurassic

The Talbragar Fish Beds

Sources & Further reading

1. Turner, S., Bean, L.B., Dettmann, M., McKellar, J. L., McLoughlin, S. & Thulborn, 2009; Australian Jurassic sedimentary and fossil successions: current work and future prospects for marine and non-marine correlation, GFF, Vol. 31, (Pt 1-2, June), pp 49-70. Stockholm, ISSN 1103-5897