Bulldog Shale

The Bulldog Shale is a formation of Early Cretaceous age (Aptian to Albian stages) that forms part of the Marree Subgroup of the Rolling Downs Group, located in the Eromanga Basin of South Australia, Queensland and New South Wales.[1][2]

Bulldog Shale
Stratigraphic range: Aptian-Albian
~
TypeGeological formation
Unit ofRolling Downs Group
 Marree Subgroup
Sub-unitsWilpoorinna Breccia Member
UnderliesCoorikiana Sandstone
OverliesCadna-owie Formation
Thickness200–340 m (660–1,120 ft)
Lithology
PrimaryMudstone, claystone
OtherShale, limestone, gypsum
Location
Coordinates30.5°S 137.2°E / -30.5; 137.2
Approximate paleocoordinates67.5°S 104.5°E / -67.5; 104.5
Region South Australia
Country Australia
ExtentEromanga Basin
Bulldog Shale is located in Australia
Bulldog Shale
Bulldog Shale
Bulldog Shale
Bulldog Shale
Bulldog Shale (Australia)
Bulldog Shale is located in South Australia
Bulldog Shale
Bulldog Shale
Bulldog Shale
Bulldog Shale
Bulldog Shale (South Australia)

Description

It is the lowermost unit in the Marree Subgroup, overlying the Cadna-owie Formation and is overlain by the Coorikiana Sandstone. The formation dates to the Aptian to Albian stages of the Early Cretaceous.[3] 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.[4]

Fossil content
See also: South Polar region of the Cretaceous

The Bulldog Shale has yielded fossils of plants, invertebrates, fish, and reptiles.[5] The macroinvertebrate fauna of this formation includes several molluscs, such belemnites, gastropods, and bivalves. Fish are represented by chimaeras[6] and ray-finned fish (these include teleosts)[6] and a lungfish. Sharks are conspicuously absent in the Bulldog Shale.[4] Many plesiosaurs are known from the formation, including leptocleidids, elasmosaurids,[4] pliosaurids, and possible polycotylids. Ichthyosaurs are also present.[7] Archosaur fossils from the Bulldog Shale are rare, and are represented mostly indeterminate specimens, some of which can be assigned to Dinosauria.[8] Due to the coastal location of the Bulldog Shale, large amounts of wood have also been recovered in this formation.[4]

Archosaurs
Archosaurs reported from the Bulldog Shale
GenusSpeciesLocationMaterialNotesImages
Archosauria Indet. Andamooka, Coober Pedy Various fragments, some opalized Includes some material referable to Dinosauria (Theropoda)[8]
Kakuru K. kujani Andamooka Opalized tibia Now considered Tetanurae indet.[8]

Plesiosaurs
Plesiosaurs reported from the Bulldog Shale
GenusSpeciesLocationMaterialNotesImages
Kronosaurus K. queenslandicus Teeth Originally referred to cf. K. sp.[4][7]
Leptocleidus L. sp. Reclassified as Umoonasaurus[7]
Opallionectes O. andamookaensis Lunatic Hill opal field Opalized incomplete articulated skeleton A plesiosaur of uncertain classification[4][7]
Umoonasaurus U. demoscyllus Zorba Extension Opal Field, Andamooka opal fields, Curdimurka area, Neales River region Opalized skulls and skeletons A small leptocleidid[9] plesiosaur with three crests on its head[2]
Elasmosauridae Indet. Andamooka Partial skeletons and several fragments [4]
Polycotylidae Indet. Hermit Hill Fragmentary specimen [4]

Ichthyosaurs
Ichthyosaurs reported from the Bulldog Shale
GenusSpeciesLocationMaterialNotesImages
Platypterygius P. sp. Bopeechee Siding Fragmentary cranial and postcranial material The specimen SAM P14508 shows evidence of healed bite marks.[5]

Chondrichthyes
Chondrichthyans reported from the Bulldog Shale
GenusSpeciesLocationMaterialNotesImages
Ptyktoptychion P. eyrensis Near Lake Eyre in northern South Australia [10][11]

Invertebrates
Invertebratess reported from the Bulldog Shale
GenusSpeciesLocationMaterialNotesImages
Isocrinus I. australis Opalised calyx [12]
Maccoyella M. barklyi [13]
Pursiphonia P. clarkei Opalised sponge remains [12]
Tropaeum T. imperator [13]
Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
 Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

See also

References
  1. Geoscience Australia. "Stratigraphic Unit Details: Bulldog Shale". Australian Stratigraphic Units Database. Retrieved 26 June 2020.
  2. 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.
  3. Bulldog Shale at Fossilworks.org
  4. 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. Bibcode:2006Palgy..49..837K. doi:10.1111/j.1475-4983.2006.00569.x. S2CID 128232205.
  5. 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.
  6. McHenry, Colin R. (2009). Devourer of Gods: The palaeoecology of the Cretaceous pliosaur Kronosaurus queenslandicus (Thesis). The University of Newcastle.
  7. 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.
  8. 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.
  9. 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.
  10. Kear, Benjamin P. (2011). Dinosaurs in Australia : Mesozoic life from the Southern Continent. Robert J. Hamilton-Bruce, CSIRO Publishing. Collingwood, Vic.: CSIRO Pub. p. 86. ISBN 978-0-643-10169-2. OCLC 692219338.
  11. Popov, Evgeny V. (2020-12-10). "Systematic reassessment of Edaphodon eyrensis Long, 1985 (Holocephali, Chimaeroidei) from the Early Cretaceous of South Australia". Journal of Vertebrate Paleontology. 40 (6): e1884564. doi:10.1080/02724634.2020.1884564. ISSN 0272-4634.
  12. Kear, Benjamin P. (2011). Dinosaurs in Australia : Mesozoic life from the Southern Continent. Robert J. Hamilton-Bruce, CSIRO Publishing. Collingwood, Vic.: CSIRO Pub. p. 82. ISBN 978-0-643-10169-2. OCLC 692219338.
  13. Kear, Benjamin P. (2011). Dinosaurs in Australia : Mesozoic life from the Southern Continent. Robert J. Hamilton-Bruce, CSIRO Publishing. Collingwood, Vic.: CSIRO Pub. p. 83. ISBN 978-0-643-10169-2. OCLC 692219338.

Further reading
  • B. P. Kear. 2007. A juvenile pliosauroid plesiosaur (Reptilia: Sauropterygia) from the Lower Cretaceous of South Australia. Journal of Paleontology 81(1):154-162
  • R. E. Molnar. 1991. Fossil reptiles in Australia. In P. Vickers-Rich, J. M. Monaghan, R. F. Baird, & T. H. Rich (eds.), Vertebrate Paleontology of Australasia 605-702
  • R. E. Molnar. 1980. Australian late Mesozoic continental tetrapods: some implications. Mémoires de la Société Géologique de France, Nouvelle Série 139:131-143
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