| Khok Kruat Formation | |
| Type: | Geological formation |
| Age: | Aptian ~ |
| Period: | Aptian |
| Prilithology: | Sandstone, siltstone |
| Otherlithology: | Conglomerate, shale |
| Namedby: | Ward & Bunnag |
| Year Ts: | 1964 |
| Region: | Indochina |
| Coordinates: | 15.9°N 102°W |
| Paleocoordinates: | 16.3°N 105.3°W |
| Unitof: | Khorat Group |
| Underlies: | Maha Sarakham Formation |
| Overlies: | Phu Phan Formation |
| Extent: | Khorat Plateau |
The Khok Kruat Formation is a rock formation found in northeastern Thailand. It is the uppermost formation of the Khorat Group.[1] It is dated to the Aptian stage of the Early Cretaceous period, and is notable for its fossils of dinosaurs. It is equivalent to the Gres superieurs Formation of Laos.[2] The group is a fluvial formation consisting primarily of red siltstones and sandstones.
The Khok Kruat Formation has yielded remains of sharks, fishes, turtles, crocodilians and pterosaurs. Phuwiangosaurus-like teeth, Siamosaurus teeth, and fragmentary postcranial remains of spinosaurids have also been recovered from it.[3] Fukuiraptor-like teeth have also been recovered from the formation.[4]
| Dinosaurs reported from the Khok Kruat Formation | |||||
|---|---|---|---|---|---|
| Genus | Species | Location | Material | Notes | Images |
| cf. Asianopodus | cf. A. isp. | "Huai Dam Chum site, Ban Lao Nat, Tha Uthen District, Nakhon Phanom Province".[5] | "At least 79 trackways composed of 341 consecutive tracks in total". | Theropod tracks. | |
| Ichnogen. et. sp. indet. | "Huai Dam Chum site, Ban Lao Nat, Tha Uthen District, Nakhon Phanom Province". | "Two trackways: T23 composed of 6 consecutive tracks and T35 composed of 3 discontinuous tracks". | Flattened possible theropod tracks. | ||
| Psittacosaurus | P. sattayaraki[6] | Ban Dong Bang Noi | "Well preserved left dentary and an incomplete maxilla." | A ceratopsian | |
| Ratchasimasaurus | R. suranareae | Nakhon Ratchasima province.[7] | An iguanodontian ornithopod | ||
| Siamodon | S. nimngami[8] | Ban Saphan Hin | PRC-4, a well-preserved left maxilla, PRC-5, an isolated maxillary tooth and PRC-6, a braincase. | An iguanodontian ornithopod | |
| Sirindhorna | S. khoratensis | Muaeng Nakhon Ratchasima District, Nakhon Ratchasima Province.[9] | An iguanodontian ornithopod | ||
| Siamosaurus | S. sp.[10] | Teeth | A spinosaurid | ||
| Siamraptor | S. suwati | Muaeng Nakhon Ratchasima District, Nakhon Ratchasima Province.[11] | "A composite cranial and postcranial skeleton comprising premaxilla, maxilla, jugal, surangular, prearticular, articular, vertebrae, manual ungual, ischium, tibia, and pedal phalanx". | A carcharodontosaur | |
| Pseudosuchians reported from the Khok Kruat Formation | |||||
|---|---|---|---|---|---|
| Genus | Species | Location | Material | Notes | Images |
| Atoposauridae indet. | Indeterminate | Lam Pao Reservoir, Ban Noi, Sahatsakhan district, Kalasin province.[12] | An isolated lanceolate tooth (PRCMR 282). | May be attributable to Theriosuchus. | |
| Khoratosuchus | K. jintasakuli | Ban Saphan Hin, Nakhon Ratchasima province.[13] | A partial skull (NNRU-A 1803). | An advanced neosuchian. | |
| Turtles reported from the Khok Kruat Formation | |||||
|---|---|---|---|---|---|
| Genus | Species | Location | Material | Notes | Images |
| Kizylkumemys | K. khoratensis | Ban Saphan Hin and Ban Khok Kruat localities, Nakhon Ratchasima province.[14] | Shell material. | A carettochelyid. | |
| Shachemys | S. sp. | Ban Saphan Hin, Nakhon Ratchasima province. | Shell material. | An adocid, remains too fragmentary for specific assignment. | |
| Bony fish reported from the Khok Kruat Formation | |||||
|---|---|---|---|---|---|
| Genus | Species | Location | Material | Notes | Images |
| Khoratamia | K. phattharajani | Ban Krok Duean Ha, Nakhon Ratchasima province.[15] | Holotype (NRRU-F01020023), paratype (NRRU-F01020024) and a patch of scales (NRRU-F01020025). | An amiid. | |
| Lanxangichthys | L. sp. | Khok Pha Suam, Ubon Ratchathani province.[16] | A lepisosteiform. | ||
| Cartilaginous fish reported from the Khok Kruat Formation | |||||
|---|---|---|---|---|---|
| Genus | Species | Location | Material | Notes | Images |
| Acrorhizodus | A. khoratensis | Khok Pha Suam locality, Ubon Ratchathani province.[17] | 5 teeth, most of them incomplete. | A hybodontiform. | |
| Heteroptychodus | H. aff. steinmanni | Khok Pha Suam locality, Ubon Ratchathani province. | 20 teeth, most incomplete. | A ptychodontid. | |
| Hybodus? | H.? sp. | Khok Pha Suam locality, Ubon Ratchathani province. | 22 incomplete teeth. | Possibly represents a new genus, but the available material is too fragmentary to warrant erecting a new taxon. | |
| Thaiodus | T. ruchae | Khok Pha Suam locality, Ubon Ratchathani province. | One incomplete tooth. | A hybodontid. | |