Lameta Formation

The Lameta Formation, also known as the Infratrappean Beds (not to be confused with the contemporaneous Intertrappean Beds), is a sedimentary geological formation found in Madhya Pradesh, Gujarat, and Maharashtra, India, associated with the Deccan Traps. It is of Maastrichtian age (Late Cretaceous), and is notable for its dinosaur fossils. Many dubious names have been created for isolated bones, but several genera of dinosaurs from these rocks are well-supported, including the titanosaur sauropod Isisaurus and the abelisaurs Indosaurus, Indosuchus, Laevisuchus, and Rajasaurus.[1] As well as mammals, snakes and other fossils.

Lameta Formation
Stratigraphic range: Maastrichtian
~
Exposure of the Lameta Formation at its type locality of Lameta
TypeGeological formation
UnderliesDeccan Traps deposits
OverliesJabalpur Group or Precambrian Basement
Area5,000 km2 (1,900 sq mi)
ThicknessVariable, typically 18–45 m (59–148 ft)
Lithology
PrimaryClaystone, sandstone limestone
OtherConglomerate
Location
Coordinates23.2°N 80.0°E / 23.2; 80.0
Approximate paleocoordinates24.7°S 63.2°E / -24.7; 63.2
RegionWestern India
Country India
ExtentMadhya Pradesh, Gujarat, Maharashtra
Type section
Named forLameta Ghat
Lameta Formation is located in India
Lameta Formation
Lameta Formation (India)

Lithology

The formation is underlain by the Lower Cretaceous sedimentary "Upper Gondwana Sequence" also known as the Jabalpur Formation, and is overlain by the Deccan Traps basalt. The Lameta Formation is only exposed at the surface as small isolated outcrops associated with the Satpura Fault. The lithology of the formation, depending on the outcrop, consists of alternating clay, siltstone and sandstone facies, deposited in fluvial and lacustrine conditions. The environment at the time of deposition has alternatively been considered semi-arid, or tropical humid.[2][3]

Fossil content

Dinosaurs
The fossilized sauropod egg discovered in Lameta Formation
Life restoration of dinosaurs in Lameta Formation
GenusSpeciesLocationStratigraphic positionMaterialNotesImages
Indosaurus I. matleyi Bara Simla Partial skeleton, including a partial skull.[4]
Brachypodosaurus B. gravis "Humerus."[5]
Coeluroides C. largus Bara Simla "Isolated vertebrae."[6]
Dryptosauroides D. grandis Bara Simla "Vertebrae."[6]
Indosuchus I. raptorius Bara Simla Cranial remains, including two braincases, as well as a nearly complete skeleton.[4] An Abelisaurid theropod.
Isisaurus I. colberti Dongargaon Hill A titanosaur.
Jainosaurus J. septentrionalis Bara Simla "Basicranium and partial postcranial skeleton."[7] A titanosaur.
Jubbulpuria J. tenuis "Vertebrae."[6]
Lametasaurus L. indicus Bara Simla "Sacrum, ilia, tibia."[6] "Sacrum, ilia, tibia, spines, armor."[8]
Laevisuchus L. indicus Bara Simla Only vertebrae.[4]
Ornithomimoides O. barasimlensis Bara Simla "Vertebrae."[6]
O. mobilis Bara Simla "Vertebrae"[6]
Orthogoniosaurus O. matleyi Bara Simla "Tooth"[6]
Rahiolisaurus R. gujaratensis Rahioli Village An Abelisaurid theropod.
Rajasaurus R. narmadensis Temple Hill, Rahioli An Abelisaurid theropod.
Titanosaurus T. blanfordi "Caudal vertebrae."[9]
T. indicus "Teeth"[10]

Snakes
GenusSpeciesLocationStratigraphic positionMaterialNotesImages
Sanajeh S. indicus A skull, precloaca vertebrae and ribs. A madtsoiid snake
Sanajeh about to attack a titanosaur hatchling
Madtsoia M. pisdurensis[11] A madtsoiid snake

Turtles
GenusSpeciesLocationStratigraphic positionMaterialNotesImages
Jainemys J. pisdurensis A bothremydid side-necked turtle

See also

References
  1. Weishampel et al., 2004, pp.517-606
  2. Srivastava, Ashok K.; Mankar, Rupesh S. (January 2015). "Lithofacies architecture and depositional environment of Late Cretaceous Lameta Formation, central India". Arabian Journal of Geosciences. 8 (1): 207–226. doi:10.1007/s12517-013-1192-y. ISSN 1866-7511. S2CID 67851941.
  3. Kumari, Anjali; Singh, Seema; Khosla, Ashu (January 2021). "Palaeosols and palaeoclimate reconstruction of the Maastrichtian Lameta Formation, Central India". Cretaceous Research. 117: 104632. Bibcode:2021CrRes.11704632K. doi:10.1016/j.cretres.2020.104632. S2CID 224946979.
  4. "Table 3.1," in Weishampel, et al. (2004). Page 49.
  5. "Table 17.1," in Weishampel, et al. (2004). Page 367.
  6. "Table 3.1," in Weishampel, et al. (2004). Page 50.
  7. "Table 13.1," in Weishampel, et al. (2004). Page 269.
  8. "Table 17.1," in Weishampel, et al. (2004). Page 368.
  9. "Table 13.1," in Weishampel, et al. (2004). Page 270.
  10. "Table 13.1," in Weishampel, et al. (2004). Page 271.
  11. Mohabey, D.M.; Head, J.J.; Wilson, J.A. (2011). "A new species of the snake Madtsoia from the Upper Cretaceous of India and its paleobiogeographic implications". Journal of Vertebrate Paleontology. 31 (3): 588–595. Bibcode:2011JVPal..31..588M. doi:10.1080/02724634.2011.560220. S2CID 129792355.

Bibliography
  • Weishampel, David B.; Peter Dodson, and Halszka Osmólska (eds.). 2004. The Dinosauria, 2nd edition, 1–880. Berkeley: University of California Press. Accessed 2019-02-21. ISBN 0-520-24209-2
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