Koonwarria

Koonwarria
Temporal range: Early Cretaceous (Aptian)
Reconstruction of adult and juvenile
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Division: Teleostei
Family: †Koonwarriidae
Waldman, 1971
Genus: †Koonwarria
Waldman, 1971
Species:
†K. manifrons
Binomial name
†Koonwarria manifrons
Waldman, 1971

Koonwarria manifrons is an extinct species of freshwater ray-finned fish that lived in a polar lake in what is now Koonwarra, Victoria, Australia during the Early Cretaceous (Aptian) epoch. Fossils have been retrieved from the Koonwarra Fossil Bed, part of the Strzelecki Group.

Koonwarria manifrons shares many anatomical similarities with the family Archaeomaenidae, and is assumed to be descended from the archaeomaenids, but, is regarded as distinct enough to be placed in its own monotypic family, Koonwarriidae. It is known from 4 incomplete specimens, the largest of which is about 290 millimetres (0.95 ft) in length. Some authors assigned it to the Clupeiformes based on superficial similarities, but later studies have refuted this.

The lake that Koonwarria inhabited was situated in a cold, humid montane habitat, which experienced periods of polar night during the winter months. Some authors have suggested that the lake periodically froze over and thawed during the winter, leading to frequent die-offs of organisms, but other authors dispute this theory and suggest that these death assemblages are more indicative of frequent flooding.

References

  1. ↑ Sepkoski, Jack (2002). "A compendium of fossil marine animal genera". Bulletins of American Paleontology. 364: 560. Archived from the original on July 23, 2011. Retrieved 2009-02-27.
  2. 1 2 Waldman, Michael. Fish from the freshwater Lower Cretaceous of Victoria, Australia: with comments on the palaeo-environment. No. 9. Palaeontological Association, 1971.
  3. 1 2 Poropat, Stephen F.; Martin, Sarah K.; Tosolini, Anne-Marie P.; Wagstaff, Barbara E.; Bean, Lynne B.; Kear, Benjamin P.; Vickers-Rich, Patricia; Rich, Thomas H. (2018-04-03). "Early Cretaceous polar biotas of Victoria, southeastern Australia—an overview of research to date". Alcheringa: An Australasian Journal of Palaeontology. 42 (2). Taylor & Francis: 157–229. doi:10.1080/03115518.2018.1453085. ISSN 0311-5518.
  4. 1 2 Bean, Lynne B. (2017-07-25). "Reappraisal of Mesozoic fishes and associated invertebrates and flora from Talbragar and Koonwarra, eastern Australia". Proceedings of the Royal Society of Victoria. 129 (1): 7–20. doi:10.1071/RS17001. ISSN 0035-9211.