Kallamedu Formation
Geologic formation in India
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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]
| Kallamedu Formation | |
|---|---|
| Stratigraphic range: Maastrichtian to Danian ~ | |
| Type | Geological formation |
| Unit of | Ariyalur Group |
| Underlies | Niniyur Formation |
| Overlies | Archean Basement |
| Thickness | Variable, typically 5–5,000 km (3.1–3,106.9 mi) |
| Lithology | |
| Primary | Claystone, siltstone limestone |
| Other | Conglomerate |
| Location | |
| Coordinates | 11.6962°N 79.4127°E |
| Country | India |
| Extent | Kallamedu |
| Type section | |
| Named for | Kallamedu village |
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
|
Notes Uncertain or tentative taxa are in small text; |
Dinosaurs
| Dinosaurs from the Kallamedu Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Material | Notes | |||
| 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. 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. | |||
| 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 | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Material | Notes | |||
| Crocodilia[13] | Indeterminate | Teeth. | ||||
| Simosuchus [13] | cf. Simosuchus sp. | Teeth. | Notosuchian Related to Simosuchus. | |||
Turtles
| Turtle from the Kallamedu Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Material | Notes | |||
| Kurmademys [14] | K. kallamedensis | Nearly complete skull. | A Side-necked Turtle. | |||
| Testudines[13] | Indeterminate | Several fragmentary pieces of carapace and one vetebral element. | Too fragmentary to compare with Kurmademys. | |||
Fish
| Fish from the Kallamedu Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Material | Notes | |||
| Lepisosteidae[13] | Indeterminate. | Scales. | Similar scales are known from the Intertrappean Beds. | |||
Amphibians
| Amphibians from the Kallamedu Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Material | Notes | |||
| Anura[13] | Indeterminate. | Fragmentary ilium. | ||||