Karai Formation
Geologic formation in India
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The Karai Formation is a Mesozoic (Albian to Turonian) geologic formation in India. Fossilized ichthyosaur remains and shark teeth have been reported from this formation.[1]
Sub-unitsOdiyam & Kunnam Members
UnderliesUnconformity with the Kulakkalnattam formation
OverliesUttatur Group
| Karai Formation | |
|---|---|
| Stratigraphic range: Albian to Turonian ~ | |
| Type | Geological formation |
| Sub-units | Odiyam & Kunnam Members |
| Underlies | Unconformity with the Kulakkalnattam formation |
| Overlies | Uttatur Group |
| Lithology | |
| Primary | Mudstone |
| Location | |
| Coordinates | 11.0°N 78.90°E |
| Region | Tamil Nadu, Cauvery basin |
| Country | India |
  Karai Formation (India) | |
Paleobiota
Color key
|
Notes Uncertain or tentative taxa are in small text; |
Ichthyosaurs
| Ichthyosaurs from the Karai Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Material | Notes | Images | |
| Ichthyosauria | indet.[2] | Vertebrae. | Previously known as "Platypterygius indicus".[3] | |||
| Ichthyosaurus[4] | I. indicus | A few complete and one partially complete vertebrae. | Considered a nomen dubium.[5] | |||
| Ichthyosauria | indet.[6] |
|
Was tentatively assigned to P. indicus. It is similar to other species of Platypterygius.[1] It was later noted that only one of the teeth can be assigned to Platypterygiinae.[6] | |||
| Platypterygius | P. sp. indet. | An Anterior caudal vertebra. | A Platypterygiine ichthyosaur.[7] | |||
Chondrichthyans
| Chondrichthyans from the Karai Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Material | Notes | Images | |
| Protosqualus | P. sp. | One incomplete tooth. | A Squalid shark.[1] | |||
| Gladioserratus | G. magnus | One lower lateral tooth. | A Hexanchid shark.[1] | |||
| ?Notidanodon | ?N. sp. | One tooth fragment. | A Hexanchid shark.[1] | |||
| Cretalamna | C. appendiculaia | Twenty-five teeth. | An Otodontid shark.[1] | |||
| Dwardius | D. sudindicus | Over a hundred teeth. | A Lamniform shark.[1] | |||
| ?Eostriatolamia | ?E. sp. | One upper lateral tooth and a cusp of an anterior tooth. | An Odontaspidid shark.[1] | |||
| Squalicorax | S. aff. baharijensis | Five complete and two fragmentary teeth. | An Anacoracid shark.[1] | |||
| Cretodus | C. longiplicatus | Fifteen teeth. | A Lamniform shark.[1] | |||
Mollusk
| Mollusks from the Karai Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Material | Notes | Images | |
| Acanthoceras | A. rhotomagense | An Acanthoceratidae Ammonite. | ||||
| Calycoceras |
|
An Acanthoceratidae Ammonite. | ||||
| Pseudocalycoceras |
|
An Acanthoceratidae Ammonite. | ||||
| Kunnamiceras | K. tropicum | An Acanthoceratidae Ammonite. | ||||
| Eucalycoceras | E. pentagonum | An Acanthoceratidae Ammonite. | ||||
| Lotzeites | L. aberrans | An Acanthoceratidae Ammonite. | ||||
| Desmoceras |
|
A Desmoceratidae Ammonite. | ||||
| Sciponoceras | sp. | A Baculitidae Ammonite. | ||||
| Phylloceras | P. seresitense | A Phylloceratidae Ammonite. | ||||
| Holcodiscoides | H. elegans | A Kossmaticeratidae Ammonite. | ||||
| Cymatoceras | C. huxleyanum | A Nautilidae. | ||||
| Eutrephoceras | E. justum | A Nautilidae. | ||||
| Pycnodonte | P. vesicularis | An Oyster. | ||||