Earth:Bulldog Shale

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Bulldog Shale
Stratigraphic range: Aptian-Albian
~120–110 Ma
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
Coordinates [ ⚑ ] : 30°30′S 137°12′E / 30.5°S 137.2°E / -30.5; 137.2
Paleocoordinates [ ⚑ ] 67°30′S 104°30′E / 67.5°S 104.5°E / -67.5; 104.5
Region South Australia
Country Australia
ExtentEromanga Basin
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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]

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

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]

Paleobiota

Archosaurs

Archosaurs reported from the Bulldog Shale
Genus Species Location Material Notes Images
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
Genus Species Location Material Notes Images
Kronosaurus K. queenslandicus Teeth Originally referred to cf. K. sp.[4][7]
Kronosaurus.jpg
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]
Umoonasaurus demoscyllus.png
Elasmosauridae Indet. Andamooka Partial skeletons and several fragments [4]
Polycotylidae Indet. Hermit Hill Fragmentary specimen [4]

Ichthyosaurs

Ichthyosaurs reported from the Bulldog Shale
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.[5]
Platypterigius longmani DB.jpg

Chondrichthyes

Chondrichthyans reported from the Bulldog Shale
Genus Species Location Material Notes Images
Ptyktoptychion P. eyrensis Near Lake Eyre in northern South Australia [10][11]

Invertebrates

Invertebratess reported from the Bulldog Shale
Genus Species Location Material Notes Images
Isocrinus I. australis Opalised calyx [12]
Maccoyella M. barklyi [13]
Pursiphonia P. clarkei Opalised sponge remains [12]
Tropaeum T. imperator [13]


See also

References

  1. ↑ Geoscience Australia. "Stratigraphic Unit Details: Bulldog Shale". https://asud.ga.gov.au/search-stratigraphic-units/results/2891. 
  2. ↑ 2.0 2.1 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. PMID 17148303. 
  3. ↑ Bulldog Shale at Fossilworks.org
  4. ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 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. doi:10.1111/j.1475-4983.2006.00569.x. Bibcode: 2006Palgy..49..837K. 
  5. ↑ 5.0 5.1 Zammit, Maria; Kear, Benjamin P. (2011). "Healed bite marks on a Cretaceous ichthyosaur". Acta Palaeontologica Polonica 56 (4): 859–863. doi:10.4202/app.2010.0117. http://app.pan.pl/archive/published/app56/app20100117.pdf. 
  6. ↑ 6.0 6.1 McHenry, Colin R. (2009). Devourer of Gods: The palaeoecology of the Cretaceous pliosaur Kronosaurus queenslandicus (Thesis). The University of Newcastle.
  7. ↑ 7.0 7.1 7.2 7.3 Kear, Benjamin P. (2016). "Cretaceous marine amniotes of Australia: perspectives on a decade of new research". Memoirs of Museum Victoria 74: 17–28. doi:10.24199/j.mmv.2016.74.03. https://museumsvictoria.com.au/media/4238/017-028_mmv74_kear_2_web.pdf. 
  8. ↑ 8.0 8.1 8.2 Barrett, Paul M.; Kear, Benjamin P.; Benson, Roger B.J. (2010). "Opalized archosaur remains from the Bulldog Shale (Aptian: Lower Cretaceous) of South Australia". Alcheringa 34: 1–9. ISSN 0311-5518. http://eprints.esc.cam.ac.uk/1392/1/Barrett_et_al_2010.pdf. 
  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. https://www.researchgate.net/publication/282942268. 
  10. ↑ Kear, Benjamin P. (2011). Dinosaurs in Australia : Mesozoic life from the Southern Continent. Robert J. Hamilton-Bruce, CSIRO Publishing. Collingwood, Vic.: CSIRO Pub. pp. 86. ISBN 978-0-643-10169-2. OCLC 692219338. https://www.worldcat.org/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" (in en). Journal of Vertebrate Paleontology 40 (6): e1884564. doi:10.1080/02724634.2020.1884564. ISSN 0272-4634. https://www.tandfonline.com/doi/full/10.1080/02724634.2020.1884564. 
  12. ↑ 12.0 12.1 Kear, Benjamin P. (2011). Dinosaurs in Australia : Mesozoic life from the Southern Continent. Robert J. Hamilton-Bruce, CSIRO Publishing. Collingwood, Vic.: CSIRO Pub. pp. 82. ISBN 978-0-643-10169-2. OCLC 692219338. https://www.worldcat.org/oclc/692219338. 
  13. ↑ 13.0 13.1 Kear, Benjamin P. (2011). Dinosaurs in Australia : Mesozoic life from the Southern Continent. Robert J. Hamilton-Bruce, CSIRO Publishing. Collingwood, Vic.: CSIRO Pub. pp. 83. ISBN 978-0-643-10169-2. OCLC 692219338. https://www.worldcat.org/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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