Wonthaggi Formation

The Wonthaggi Formation is an informal geological formation in Victoria, Australia whose strata date back to the Early Cretaceous. It is part of the Strzelecki Group within the Gippsland Basin. Dinosaur remains are among the fossils that have been recovered from the formation.^[1][2] It is partially equivalent to the Eumeralla Formation.

Wonthaggi Formation
Stratigraphic range: Valanginian–Barremian PreꞒ Ꞓ O S D C P T J K Pg N
Flat rocks locality
Type	Geological formation
Unit of	Strzelecki Group
Underlies	Unconformity with Wombat Volcanics & Kersop Arkose
Overlies	Paleozoic basement
Thickness	Up to 2,500 m (8,200 ft)
Lithology
Primary	Volcaniclastic sandstone, siltstone
Other	Conglomerate, coal
Location
Coordinates	38.7°S 145.7°E / -38.7; 145.7
Approximate paleocoordinates	77.0°S 117.5°E / -77.0; 117.5
Region	Victoria
Country	Australia
Extent	Gippsland Basin
Exposure of Wonthaggi Formation green in bottom-right

Geology

The Wonthaggi Formation was deposited within Gippsland Basin, which formed part of a extensional rift valley system between Australia and Antarctica. The lithology primarily consists of fluvially deposited siliciclastics derived from volcanic rocks of the Whitsunday Silicic Large Igneous Province to the East, with suggestions that the sediments either originated from braided river and sheet flood deposits, or meandering river systems on vegetated floodplains.^[3] The age of the formation is thought to be Valanginian to Barremian, with the Flat Rocks site being late Barremian (~125 Ma) in age, older than the sediments from the Eumeralla Formation, which are thought to be Aptian-Albian in age.^[3]

Vertebrate paleofauna

Indeterminate ornithopod remains are present in Victoria, Australia.^[3] Indeterminate megaraptorid remains are present in Victoria, Australia.^[4]

Amphibians

Amphibians of the Wonthaggi Formation
Genus	Species	Presence	Notes	Images
Koolasuchus	K. cleelandi	Tree Trunk Point, Dwyers Hill, San Remo	Chigutisaurid temnospondyl, last known temnospondyl

Dinosaurs

Ornithischians

Ornithischians of the Wonthaggi Formation
Genus	Species	Locality	Material	Notes	Images
Ankylosauria indet.[5]	Indeterminate	Flat Rocks	Teeth, dorsal vertebra, ribs, osteoderms		Atlascopcosaurus Qantassaurus
cf. Atlascopcosaurus[3]	cf. A. loadsi[3]	Flat Rocks	known as "Victorian ornithopod maxillary morphotype 4", consists of a partial right maxilla	Intermediate in morphology between Galleonosaurus and Atlascopcosaurus
Galleonosaurus[3]	G. dorisae[3]	Flat Rocks	Known from a maxilla
Qantassaurus[1]	Q. intrepidus[1]	Flat Rocks	"[Three] dentaries and teeth."[6]
	Q. ?intrepidus[3]	Flat Rocks	Known as "Victorian ornithopodan dentary morphotype 2", represented by two dentary fragments,	Possibly distinct from Q. intrepidus
Serendipaceratops[1]	S. arthurclarkei[1]	The Arch, Kilcunda	Single damaged ulna
Ornithopoda indet.[3]	Indeterminate	Flat Rocks	Dentaries referred to as "Victorian ornithopodan dentary morphotype 3" including P228408, NMV P231182, NMV P199135 and isolated teeth	Different from Q. intrepidus.
Ornithopoda indet.[3]	Indeterminate	Cape Paterson	single femur	Known as "Victorian Hypsilophodontid Femur Type 2". Larger than contemporaneous ornithopods.

Theropods

Theropods of the Wonthaggi Formation
Genus	Species	Locality	Material	Notes	Images
Aves[7]	Indeterminate	Possibly also present at the Eumeralla Formation (footprints).	Single furcula.
Megaraptora indet.	Indeterminate	Flat Rocks	Numerous isolated teeth, and a left astragalus[8]	Originally referred to "Allosaurus" robustus
Megaraptoridae indet.[9]	Indeterminate	Shack Bay	a complete frontal, attached to a partial parietal
Noasauridae[10]	Indeterminate	San Remo Member	NMV P221202, astragalocalcaneum	A non-elaphrosaurine noasaurid.

Mammals

Mammals of the Wonthaggi Formation
Genus	Species	Presence	Material	Notes	Images
Ausktribosphenos	A. nyktos	Flat rocks	Partial dentary with teeth	Ausktribosphenid
Bishops	B. whitmorei		Partial dentary with teeth	Ausktribosphenid
Corriebaatar	C. marywaltersae		"NMV P216655, a fragment of a left dentary bearing a complete plagiaulacoid p4 and the anterior root of m1"	Multituberculate
Kryoparvus	K. gerriti		Partial dentary with teeth	?Ausktribosphenid
Teinolophos	T. trusleri		Partial dentary with teeth	Monotreme

See also

• List of dinosaur-bearing rock formations
• South Polar region of the Cretaceous