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Kallamedu Formation

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Kallamedu Formation
Stratigraphic range: Maastrichtian to Danian
~70.6–65.5 Ma
TypeGeological formation
Unit ofAriyalur Group
UnderliesNiniyur Formation
OverliesArchean Basement
ThicknessVariable, typically 5–5,000 km (3.1–3,106.9 mi)
Lithology
PrimaryClaystone, siltstone limestone
OtherConglomerate
Location
Coordinates11°41′46″N 79°24′46″E / 11.6962°N 79.4127°E / 11.6962; 79.4127
CountryIndia
ExtentKallamedu
Type section
Named forKallamedu village

The Kallamedu Formation is an Upper 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]

Lithology

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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

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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.

Dinosaurs

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Dinosaurs from the Kallamedu Formation
GenusSpeciesMaterialNotesImages
Abelisauridae indet.[4] Indeterminate. "Disassociated remains" and teeth.
Bruhathkayosaurus[5][6] B. matleyi ilium and ischium, femur, tibia, radius and part of a vertebra (specifically a platycoelous caudal centrum). Remains no longer exist Initially described as a Theropod, it was reclassified as a Titanosaur.
Carnosauria indet.?[5] Indeterminate. "Fragmentary remains" Carnosauria was often used as a wastebasket taxon.
?Camarasauridae[7] Indeterminate. Vertebrae. Camarasaurids are not known from the Cretaceous.
Fusioolithus[8] F. baghensis Dinosaur eggs.
Megalosaurus[9] M.sp. A partial tooth, length of 1.8 inches, antero-posterior diameter of 0.9 inches and transverse diameter of 0.4 inches. The tooth is almost similar to Megalosaurus in shape and size though the posterior border is straigher. Megalosaurus was often used as a waste basket taxon.
Sauropoda Indeterminate.[10][11] "Fragmentary remains."
?Stegosauria[12] Indeterminate. Misinterpreted sauropod bone. Other more plausible Stegosaur material is known from Cretaceous India.
Titanosauria Indeterminate.[8] Solitary egg.
Titanosauria Indeterminate.[13] 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]
Troodontidae indet.[4] Indeterminate. Two teeth (DUGF/52 and DUGF/168).[14] Close morphological resemblance to Troodon

Crocodylomorphs

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Crocodylomorphs from the Kallamedu Formation
GenusSpeciesMaterialNotes Images
Crocodilia[15] Indeterminate Teeth.
Simosuchus[15] cf.S. sp. Teeth. Notosuchian Related to Simosuchus.

Turtles

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Turtle from the Kallamedu Formation
GenusSpeciesMaterialNotes
Kurmademys[16] K. kallamedensis Nearly complete skull. A Side-necked Turtle.
Testudines[15] Indeterminate Several fragmentary pieces of carapace and one vetebral element. Too fragmentary to compare with Kurmademys.

Fish

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Fish from the Kallamedu Formation
GenusSpeciesMaterialNotes
Lepisosteidae[15] Indeterminate. Scales. Similar scales are known from the Intertrappean Beds.

Amphibians

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Amphibians from the Kallamedu Formation
GenusSpeciesMaterialNotes
Anura[15] Indeterminate. Fragmentary ilium.

References

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  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. ↑ Ramasamy, S.; Ramachandran, A.; Velmurugan, K.; David Lalhmingliana Chawngthu, B. S.; Suresh Gandhi, M. (2012). "Sedimentological studies of Kallamedu Formation in Ariyalur area, Tamil Nadu, India". Int. J. Geol. Earth Environ. Sci. 2 (1): 218–234.
  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. Bibcode:2022GeolT..38..112P. doi:10.1111/gto.12390. ISSN 0266-6979.
  7. ↑ C. R. Narayana Rao and L. Rama Rao. 1930. Some dinosaurian vertebrae. Proceedings of the Indian Science Congress, Allahabad 17:329.
  8. 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.
  9. ↑ Lydekker, Richard (1877). "Notices on New and Other Vertebrata from Indian Tertiary and Secondary Rocks". Records of Geological Survey of India. 10: 41.
  10. ↑ 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
  11. ↑ C. R. Narayana Rao and L. Rama Rao. 1930. The limb bones of a sauropodous dinosaur. Proceedings of the Indian Science Congress, Allahabad 17:330.
  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. Bibcode:2017NJGPA.285...91G. doi:10.1127/njgpa/2017/0671.
  13. ↑ Matley, 1929. The Cretaceous Dinosaurs of the Trichinopoly district and the rocks associated with them. Rec. Geof. Surv. India. Vol. 61 (4):337-349.
  14. ↑ Dhiman, Harsha; Parvez, Fahad; Goswami, Anjali; Prasad, Guntupalli V. R. (2026). "A second theropod tooth from the Cauvery Basin reaffirms the presence of troodontid dinosaurs in the Cretaceous of India". The Anatomical Record. n/a (n/a) ar.70280. doi:10.1002/ar.70280. ISSN 1932-8494. PMID 42402795.
  15. 1 2 3 4 5 Prasad, Guntupalli V. R.; Verma, Omkar; Flynn, John J.; Goswami, Anjali (2013-11-01). "A new Late Cretaceous vertebrate fauna from the Cauvery Basin, South India: implications for Gondwanan paleobiogeography". Journal of Vertebrate Paleontology. 33 (6): 1260–1268. Bibcode:2013JVPal..33.1260P. doi:10.1080/02724634.2013.777348. ISSN 0272-4634.
  16. ↑ 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.
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