Deltasaurus

Deltasaurus Temporal range: Late Triassic
Restoration of Deltasaurus kimberleyensis
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Order:	†Temnospondyli
Suborder:	†Stereospondyli
Family:	†Rhytidosteidae
Subfamily:	†Derwentiinae
Genus:	†Deltasaurus Cosgriff, 1965[1]
Type species
†Deltasaurus kimberleyensis Cosgriff, 1965
Other species
†D. pustulatus Cosgriff, 1965

Deltasaurus is an extinct genus of Carnian temnospondyl amphibian of the family Rhytidosteidae.

Taxonomy

The genus was erected in 1965 by John W. Cosgriff, when describing two new species discovered northwest Australia. The author recognised an affinity with other genera allied to the family Rhytidosteidae that had been uncovered in Africa, and proposed their arrangement to a new superfamily Rhytidosteoidea.

D. kimberleyensis fossil

It is the most common animal fossil of the Blina Shale, a fossil deposit at the eastern end of the Erskine Range in the Kimberley region of Western Australia. A specimen has also been collected from the Knocklofty Sandstone deposit in Tasmania.^[2]

The genus places two fossil taxa, Deltasaurus kimberleyensis, the type species which grew to around 90 centimetres in length, and Deltasaurus pustulatus, also described by Cosgriff in 1965.^[2] The genus has been variously placed in subsequent arrangements, at one time as a familia Derwentiidae that separated the Australian taxa from Indobrachyops found on the Indian subcontinent. A revision of the Rhytidosteidae (Stereospondyli: Trematosauria) published in 2011 applied phylogenetic methodologies to reassess the relationships of the genera and submerged the Derwentiidae as a new subfamily of Rhytidosteidae that included the genus Indobrachyops as an eastern Gondwanan grouping of Australian and Indian rhytidosteids.^[3]

Distribution

A stereospondyl genus unearthed at sites located in Western Australia and Tasmania in shale deposits dated from the upper Permian to lower Triassic.^[3]

Description

A temnospondyl amphibian of the family Rhytidosteidae. It had four limbs and a tail, and numerous tiny teeth. It is thought to have been a predator of fish.^[2] Deltasaurus are distinguished from other Australia species of Rhytidosteidae by the straight side of the skull, rather than parabolic outline of Rewana quadricuneata, Arcadia myriadens and Derwentia warreni.^[4]

References

1. Cosgriff, J.W. (1965). "A new genus of Temnospondyli from the Triassic of-Western Australia". Journal of the Royal Society of Western Australia. 48: 65–90.
2. Warren, Anne (1987). "An Ancient Amphibian from Western Australia". In Hand, Suzanne and Michael Archer (ed.). The Antipodean Ark. Angus & Robertson. ISBN 0-207-15664-6.
3. Dias-da-Silva, S.; Marsicano, C. (1 June 2011). "Phylogenetic reappraisal of Rhytidosteidae (Stereospondyli: Trematosauria), temnospondyl amphibians from the Permian and Triassic". Journal of Systematic Palaeontology. 9 (2): 305–325. doi:10.1080/14772019.2010.492664. hdl:11336/68471. ISSN 1477-2019.
4. Rozefelds, A.C.; Warren, A. (September 2011). "Lepidostrobus muelleri Johnston is a skull fragment of a temnospondyl amphibian". Alcheringa: An Australasian Journal of Palaeontology. 35 (3): 459–462. doi:10.1080/03115518.2011.527163.