Kallamedu Formation

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Kallamedu Formation
Stratigraphic range: Maastrichtian to Danian
~70.6–65.5  Ma
Type Geological formation
Unit of Ariyalur Group
Underlies Niniyur Formation
Overlies Archean Basement
ThicknessVariable, typically 5–5,000 km (3.1–3,106.9 mi)
Lithology
Primary Claystone, siltstone limestone
Other Conglomerate
Location
Coordinates 11°41′46″N79°24′46″E / 11.6962°N 79.4127°E / 11.6962; 79.4127
Country India
ExtentKallamedu
Type section
Named for Kallamedu village

The Kallamedu Formation is a Late Cretaceous (Maastrichtian) geologic formation located in the Ariyalur district of Tamil Nadu, India that forms part of the Ariyalur Group. [1] It dates to the Maastrichtian of the Late Cretaceous. Dinosaur remains and petrified wood samples are among the known fossils recovered from this formation. [2]

Contents

Lithology

The Kallamedu Formation likely represented a fluvial environment. It is composed of siltstones, clays and sandstones. The high organic carbon content of some of the rocks are consistent with a swamp. [3]

Paleofauna

Color key
Taxon Reclassified taxonTaxon falsely reported as presentDubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Dinosaurs

Dinosaurs from the Kallamedu Formation
GenusSpeciesMaterialNotes
Abelisauridae indet. [4] "Disassociated remains" and teeth.
Carnosauria indet.? [5] "Fragmentary remains"Carnosauria was often used as a wastebasket taxon.
Troodontidae indet. [4] One isolated tooth (DUGF/52).
Bruhathkayosaurus [5] [6] B. matleyiilium and ischium, femur, tibia, radius and part of a vertebra (specifically a platycoelous caudal centrum). Remains no longer existInitially described as a Theropod, it was reclassified as a Titanosaur.
Sauropoda Indeterminate. [7] [8] "Fragmentary remains."
Titanosauria Indeterminate. [9] Solitary egg.
Titanosauria Indeterminate. [10] Ten large sauropod bones, some of which could be identified as a humerus or femur, proximal end of a femur and scapula. All the bones pertain to the limbs.Similar in size to Bruhathkayosaurus. [6]
Fusioolithus [9] F. baghensis Dinosaur eggs.
?Camarasauridae [11] Indeterminate.Vertebrae.Camarasaurids are not known from the cretaceous.
 ?Stegosauria [12] Indeterminate.Misinterpreted sauropod bone.Other more plausible Stegosaur material is known from Cretaceous India.

Crocodylomorphs

Crocodylomorphs from the Kallamedu Formation
GenusSpeciesMaterialNotes
Crocodilia [13] IndeterminateTeeth.
Simosuchus [13] cf. Simosuchus sp.Teeth. Notosuchian Related to Simosuchus .

Turtles

Turtle from the Kallamedu Formation
GenusSpeciesMaterialNotes
Kurmademys [14] K. kallamedensisNearly complete skull.A Side-necked Turtle.
Testudines [13] IndeterminateSeveral fragmentary pieces of carapace and one vetebral element.Too fragmentary to compare with Kurmademys.

Fish

Fish from the Kallamedu Formation
GenusSpeciesMaterialNotes
Lepisosteidae [13] Indeterminate.Scales.Similar scales are known from the Intertrappean Beds.

Amphibians

Amphibians from the Kallamedu Formation
GenusSpeciesMaterialNotes
Anura [13] Indeterminate.Fragmentary ilium.

References

  1. Memoirs of the Geological Survey of India. Oxford University. 1865. pp. 107–140.
  2. Weishampel, David B; et al. (2004). "Dinosaur distribution (Late Cretaceous, Asia)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria , 2nd, Berkeley: University of California Press. Pp. 593–600. ISBN   0-520-24209-2.
  3. https://www.researchgate.net/publication/263426844_SEDIMENTOLOGICAL_STUDIES_OF_KALLAMEDU_FORMATION_IN_ARIYALUR_AREA_TAMIL_NADU_INDIA
  4. 1 2 Goswami, A.; Prasad, G. V. R.; Verma, O.; Flynn, J. J.; Benson, R. B. J. (2013). "A troodontid dinosaur from the latest Cretaceous of India". Nature Communications. 4: 1703. Bibcode:2013NatCo...4.1703G. doi: 10.1038/ncomms2716 . PMID   23591870.
  5. 1 2 Yadagiri, P. and Ayyasami, K. (1987). "A carnosaurian dinosaur from the Kallamedu Formation (Maestrichtian horizon), Tamilnadu." In M.V.A. Sastry, V.V. Sastry, C.G.K. Ramanujam, H.M. Kapoor, B.R. Jagannatha Rao, P.P. Satsangi, and U.B. Mathur (eds.), Three Decades of Development in Palaeontology and Stratigraphy in India. Volume 1. Precambrian to Mesozoic. Geological Society of India Special Publication, 11(1): 523–528.
  6. 1 2 Pal, Saurabh; Ayyasami, Krishnan (May 2022). "The lost titan of Cauvery" . Geology Today. 38 (3): 112–116. doi:10.1111/gto.12390. ISSN   0266-6979.
  7. R. Lydekker. (1877). Notices of new and other Vertebrata from Indian Tertiary and Secondary rocks. Records of the Geological Survey of India 10(1):30–43
  8. C. R. Narayana Rao and L. Rama Rao. 1930. The limb bones of a sauropodous dinosaur. Proceedings of the Indian Science Congress, Allahabad17:330.
  9. 1 2 Dhiman, Harsha; Prasad, Guntupalli V. R.; Goswami, Anjali (2018). "Parataxonomy and palaeobiogeographic significance of dinosaur eggshell fragments from the Upper Cretaceous strata of the Cauvery Basin, South India". Historical Biology: 1–13. doi:10.1080/08912963.2018.1450408. S2CID   89969203.
  10. Matley, 1929. The Cretaceous Dinosaurs of the Trichinopoly district and the rocks associated with them. Rec. Geof. Surv. India. Vol. 61 (4):337-349.
  11. C. R. Narayana Rao and L. Rama Rao. 1930. Some dinosaurian vertebrae. Proceedings of the Indian Science Congress, Allahabad17:329.
  12. Peter M. Galton; Krishnan Ayyasami (2017). "Purported latest bone of a plated dinosaur (Ornithischia: Stegosauria), a "dermal plate" from the Maastrichtian (Upper Cretaceous) of southern India". Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 285 (1): 91–96. doi:10.1127/njgpa/2017/0671.
  13. 1 2 3 4 5 Prasad, G. V. R., Verma, O., Flynn, J. J. & Goswami, A. (2013) A new Late Cretaceous vertebrate fauna from the Cauvery basin, South India: implications for Gondwanan palaeobiogeography. Journal of Vertebrate Paleontology.
  14. Gaffney, Eugene S; Chatterjee, Sankar; Rudra, Dhiraj K. (2001). "Kurmademys, a new side-necked turtle (Pelomedusoides: Bothremydidae) from the Late Cretaceous of India" (pdf). American Museum Novitates (3321): 1–16. doi:10.1206/0003-0082(2001)321<0001:kansnt>2.0.co;2. hdl:2246/2938. S2CID   53980146.