# 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. It is partially equivalent to the Eumeralla Formation.

## 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. 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.

## Vertebrate paleofauna

Indeterminate ornithopod remains are present in Victoria, Australia. Indeterminate megaraptorid remains are present in Victoria, Australia.

### 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. | Indeterminate | Flat Rocks | Teeth, dorsal vertebra, ribs, osteoderms | | Atlascopcosaurus Qantassaurus |
| cf. Atlascopcosaurus | cf. A. loadsi | Flat Rocks | known as "Victorian ornithopod maxillary morphotype 4", consists of a partial right maxilla | Intermediate in morphology between Galleonosaurus and Atlascopcosaurus | Atlascopcosaurus Qantassaurus |
| Galleonosaurus | G. dorisae | Flat Rocks | Known from a maxilla | | Atlascopcosaurus Qantassaurus |
| Qantassaurus | Q. intrepidus | Flat Rocks | "[Three] dentaries and teeth." | | Atlascopcosaurus Qantassaurus |
| Qantassaurus | Q. ?intrepidus | Flat Rocks | Known as "Victorian ornithopodan dentary morphotype 2", represented by two dentary fragments, | Possibly distinct from Q. intrepidus | Atlascopcosaurus Qantassaurus |
| Serendipaceratops | S. arthurclarkei | The Arch, Kilcunda | Single damaged ulna | | Atlascopcosaurus Qantassaurus |
| Ornithopoda indet. | 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. | Atlascopcosaurus Qantassaurus |
| Ornithopoda indet. | Indeterminate | Cape Paterson | single femur | Known as "Victorian Hypsilophodontid Femur Type 2". Larger than contemporaneous ornithopods. | Atlascopcosaurus Qantassaurus |

#### Theropods

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

### Mammals

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