Bulldog Shale
The Bulldog Shale is a formation of Early Cretaceous age (Aptian–Albian) that forms part of the Marree Subgroup, located in the Eromanga Basin of South Australia, Queensland and New South Wales.[1][2] It is the lowermost unit in this subgroup, and is overlain by the Coorikiana Sandstone. The Bulldog Shale is composed of finely laminated carbonaceous and pyritic mudstone and claystone beds. Weathering has caused heavy leaching and bleaching in some regions of the Bulldog Shale, including those around Coober Pedy, so that the rocks are white or multicolored. These horizons contain rich opal deposits. Horizons without this bleaching are primarily composed of organic-rich shale. Gypsum, in addition to carbonate limestone concretions rich in fossils are common in these unbleached shaly horizons.[3]
Bulldog Shale Stratigraphic range: Aptian | |
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Type | Geological formation |
Unit of | Marree Subgroup |
Sub-units | Wilpoorinna Breccia Member |
Underlies | Coorikiana Sandstone |
Overlies | Cadna-owie Formation |
Area | Eromanga Basin |
Thickness | 200–340 m |
Lithology | |
Primary | Mudstone, claystone |
Other | Shale, limestone |
Location | |
Region | ![]() |
Country | ![]() |
The Bulldog Shale has yielded fossils of plants, invertebrates, fish, and reptiles.[4] The macroinvertebrate fauna of this formation includes several molluscs, such belemnites, gastropods, and bivalves. Fish are represented by chimaeras[5] and ray-finned fish (these include teleosts)[5] and a lungfish. Sharks are conspicously absent in the Bulldog Shale.[3] Many plesiosaurs are known from the formation, including leptocleidids, elasmosaurids,[3] pliosaurids, and possible polycotylids. Ichthyosaurs are also present.[6] Archosaur fossils from the Bulldog Shale are rare, and are represented mostly indeterminate specimens, some of which can be assigned to Dinosauria.[7] Due to the coastal location of the Bulldog Shale, large amounts of wood have also been recovered in this formation.[3]
Paleobiota
Color key
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Notes Uncertain or tentative taxa are in small text; |
Archosaurs
Archosaurs reported from the Bulldog Shale Formation | |||||
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Genus | Species | Location | Material | Notes | Images |
Archosauria | Indet. | Andamooka, Coober Pedy | Various fragments, some opalized | Includes some material referable to Dinosauria[7] | |
Kakuru | K. kujani | Andamooka | Opalized tibia | Now considered Tetanurae indet.[7] |
Plesiosaurs
Plesiosaurs reported from the Bulldog Shale Formation | |||||
---|---|---|---|---|---|
Genus | Species | Location | Material | Notes | Images |
Elasmosauridae | Indet. | Andamooka | Partial skeletons and several fragments | [3] | |
Kronosaurus | K. queenslandicus | Teeth | Originally referred to cf. K. sp.[3][6] | ||
Leptocleidus | L. sp. | Reclassified as Umoonasaurus[6] | |||
Opallionectes | O. andamookaensis | Lunatic Hill opal field | Opalized incomplete articulated skeleton | A plesiosaur of uncertain classification[3][6] | |
Polycotylidae | Indet. | Hermit Hill | Fragmentary specimen | [3] | |
Umoonasaurus | U. demoscyllus | Zorba Extension Opal Field, Andamooka opal fields, Curdimurka area, Neales River region | Opalized skulls and skeletons | A small leptocleidid[8] plesiosaur with three crests on its head[2] |
Ichthyosaurs
Ichthyosaurs reported from the Bulldog Shale Formation | |||||
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Genus | Species | Location | Material | Notes | Images |
Platypterygius | P. sp. | Bopeechee Siding | Fragmentary cranial and postcranial material | The specimen SAM P14508 shows evidence of healed bite marks.[4] |
Chondrichthyes
Chondrichthyans reported from the Bulldog Shale Formation | |||||
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Genus | Species | Location | Material | Notes | Images |
Edaphodon | E. eyrensis |
References
- Geoscience Australia. "Stratigraphic Unit Details: Bulldog Shale". Australian Stratigraphic Units Database. Retrieved 26 June 2020.
- Kear, Benjamin P; Schroeder, Natalie I.; Lee, Michael S.Y. (2006). "An archaic crested plesiosaur in opal from the Lower Cretaceous high-latitude deposits of Australia". Biology Letters. 2 (4): 615–619. doi:10.1098/rsbl.2006.0504. PMC 1833998. PMID 17148303.
- Kear, Benjamin P. (2006). "Marine reptiles from the Lower Cretaceous of South Australia: elements of a high‐latitude cold‐water assemblage". Palaeontology. 49 (4): 837–856.
- Zammit, Maria; Kear, Benjamin P. (2011). "Healed bite marks on a Cretaceous ichthyosaur" (PDF). Acta Palaeontologica Polonica. 56 (4): 859–863. doi:10.4202/app.2010.0117.
- McHenry, Colin R. (2009). Devourer of Gods: The palaeoecology of the Cretaceous pliosaur Kronosaurus queenslandicus (Thesis). The University of Newcastle.
- Kear, Benjamin P. (2016). "Cretaceous marine amniotes of Australia: perspectives on a decade of new research" (PDF). Memoirs of Museum Victoria. 74: 17–28. doi:10.24199/j.mmv.2016.74.03.
- Barrett, Paul M.; Kear, Benjamin P.; Benson, Roger B.J. (2010). "Opalized archosaur remains from the Bulldog Shale (Aptian: Lower Cretaceous) of South Australia" (PDF). Alcheringa. 34: 1–9. ISSN 0311-5518.
- Parrilla-Bel, Jara; Canudo, José Ignacio (2015). "On the presence of plesiosaurs in the Blesa Formation (Barremian) in Teruel (Spain)". Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 278 (2): 213–227. doi:10.1127/njgpa/2015/0526.