Karai Formation

Karai Formation
Stratigraphic range: Albian to Turonian
~105.5–89.3 Ma
TypeGeological formation
Sub-unitsOdiyam and Kunnam Members
UnderliesUnconformity with the Kulakkalnattam formation
OverliesUttatur Group
Lithology
PrimaryMudstone
Location
Coordinates11°00′N 78°54′E / 11.0°N 78.90°E / 11.0; 78.90
RegionKaveri basin, Tamil Nadu
CountryIndia
Karai Formation is located in India
Karai Formation
Karai Formation (India)
Official name
Badlands of Karai Formation
Designated2015
Designated by
Geological Survey of India

The Karai Formation is a Mesozoic (Albian to Turonian) geologic formation in India. Fossilised ichthyosaur remains and shark teeth have been reported from this formation. It is designated as a National Geological Monument by the Geological Survey of India.

Paleobiota

Chondrichthyans

Chondrichthyans
GenusSpeciesMaterialFamily
Protosqualus P. sp. An incomplete tooth Squalidae
Gladioserratus G. magnus A lower lateral tooth Hexanchidae
?Notidanodon ?N. sp. A tooth fragment
Cretalamna C. appendiculaia Twenty-five teeth Otodontidae
Dwardius D. sudindicus Over a hundred teeth Cardabiodontidae
?Eostriatolamia ?E. sp. An upper lateral tooth and a cusp of an anterior tooth Odontaspididae
Squalicorax S. aff. baharijensis Five complete and two fragmentary teeth Anacoracidae
Cretodus C. longiplicatus Fifteen teeth Pseudoscapanorhynchidae

Ichthyosaurs

Ichthyosauria
GenusSpeciesMaterialNotes
Ichthyosauria indet. Vertebrae Previously known as "Platypterygius indicus".
Ichthyosaurus I. indicus A few complete and one partially complete vertebrae. Considered a nomen dubium.
Ichthyosauria indet. Six adult teeth (DUGF/41-45), a juvenile tooth (DUGF/46), and seven partial vertebrae Earlier tentatively assigned to P. indicus. It is similar to other species of Platypterygius. It was later noted that only one of the teeth can be assigned to Platypterygiinae.
Platypterygius P. sp. indet. Anterior caudal vertebra Platypterygiine ichthyosaur.

Mollusk

Mollusks
GenusSpeciesSub-classFamily
Acanthoceras A. rhotomagense Ammonoidea Acanthoceratidae
Calycoceras C. asiaticum
C. naviculare
Pseudocalycoceras P. harpax sp.
Kunnamiceras K. tropicum
Eucalycoceras E. pentagonum
Lotzeites L. aberrans
Desmoceras D. latidorsatum sp. Desmoceratidae
Sciponoceras sp. Baculitidae
Phylloceras P. seresitense Phylloceratidae
Holcodiscoides H. elegans Kossmaticeratidae
Cymatoceras C. huxleyanum Nautilidae
Eutrephoceras E. justum
Pycnodonte P. vesicularis Gryphaeidae
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.

References

  1. 1 2 3 Underwood, Charlie J.; Goswami, Anjali; Prasad, G. V. R.; Verma, Omkar; Flynn, John J. (May 2011). "Marine vertebrates from the 'middle' Cretaceous (early Cenomanian) of South India". Journal of Vertebrate Paleontology. 31 (3): 539–552. doi:10.1080/02724634.2011.574518.
  2. ↑ "Geo-Heritage Sites". Press Information Bureau (Press release). 9 March 2016. Archived from the original on 29 September 2022. Retrieved 1 September 2018.
  3. ↑ Fischer, Valentin; Bardet, Nathalie; Benson, Roger B. J.; Arkhangelsky, Maxim S.; Friedman, Matt (2016-03-08). "Extinction of fish-shaped marine reptiles associated with reduced evolutionary rates and global environmental volatility". Nature Communications. 7 (1) 10825. Bibcode:2016NatCo...710825F. doi:10.1038/ncomms10825. ISSN 2041-1723. PMC 4786747. PMID 26953824.
  4. ↑ Foote, Robert Bruce; Lydekker, Richard (1874). Indian Tertiary and post Tertiary Vertebrata. Calcutta: Geological Survey Office. doi:10.5962/bhl.title.125505.
  5. ↑ Lydekker, R. (July 1888). "VI.—Note on the Classification of the Ichthyopterygia (with a Notice of Two New Species)". Geological Magazine. 5 (7): 309–314. Bibcode:1888GeoM....5..309L. doi:10.1017/s0016756800181968. ISSN 0016-7568.
  6. ↑ Marta Fernández (2003). "Reseña de "Handbook of Paleoherpetology. Part 8. Ichthyopterygia" de C. Mcgowan and R. Motani" (PDF). Geologica Acta. 1 (4): 363–364.
  7. 1 2 Fischer, Valentin (20 October 2016). "Taxonomy ofPlatypterygius campylodonand the diversity of the last ichthyosaurs". PeerJ. 4 e2604. doi:10.7717/peerj.2604. ISSN 2167-8359. PMC 5075704. PMID 27781178.
  8. ↑ Ayyasami, K.; Elamparuthi, S.; Gowtham, B. (1 June 2016). "An ichthyosaur vertebra from the Cretaceous (Middle Cenomanian) Karai Formation, southern India". Journal of the Geological Society of India . 87 (6): 706–708. Bibcode:2016JGSI...87..706A. doi:10.1007/s12594-016-0442-5. ISSN 0974-6889.