The Khok Kruat Formation () is a rock formation found in northeastern Thailand. It is the uppermost formation of the Khorat Group.
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.Weishampel, David B; et al. (2004). "Dinosaur distribution (Early Cretaceous, Asia)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 563-570. . The group is a fluvial formation consisting primarily of red siltstones and sandstones.
Fossil content
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. Fukuiraptor-like teeth have also been recovered from the formation.
Reptiles
Dinosaurs
Ornithischians Ornithischians reported from the Khok Kruat Formation Genus Species Location Material Notes Images Iguanodontia Indet. Indeterminate Khok Pha Suam locality, Ubon Ratchathani province. Teeth, vertebrae and limb bones Psittacosaurus P. sattayarakiBuffetaut, Eric & Suteethorn, Varavudh. (1992). A new species of the ornithischian dinosaur Psittacosaurus from the Early Cretaceous of Thailand. Palaeontology 35: 801-812. Ban Dong Bang Noi, Chaiyaphum Province "Well preserved left dentary and an incomplete maxilla." A psittacosaurid ceratopsian Ratchasimasaurus R. suranareaeNakhon Ratchasima province. A complete left dentary with no teeth A styracosternan iguanodontian Siamodon S. nimngami Ban Saphan Hin PRC-4, a well-preserved left maxilla, PRC-5, an isolated maxillary tooth and PRC-6, a braincase. A styracosternan iguanodontian Sirindhorna S. khoratensisMuaeng Nakhon Ratchasima District, Nakhon Ratchasima Province. A styracosternan iguanodontian
Sauropods Sauropods reported from the Khok Kruat Formation Genus Species Location Material Notes Images Macronaria Indet. Indeterminate Khok Pha Suam locality, Ubon Ratchathani province. Femur of juvenile, isolated teeth Nagatitan N. chaiyaphumensis Ban Pha Nang Sua several vertebrae, parts of the pelvis, and parts of the forelimb and hindlimb. A euelopodid somphospondylian
Theropods Theropods reported from the Khok Kruat Formation Genus Species Location Material Notes Imagescf. Asianopoduscf. A. isp."Huai Dam Chum site, Ban Lao Nat, Tha Uthen District, Nakhon Phanom Province"."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. Ornithomimosauria Indet. Indeterminate Ban Krok Duean Ha "NRRU-F01020052, distal part of the right metatarsal III" A ornithomimosaurian theropod Spinosaurinae Indet. Indeterminate, some tentatively assigned to Siamosaurus Teeth, postcranial materials (SM-KK 14) A spinosaurine spinosaurid Siamraptor S. suwatiMuaeng Nakhon Ratchasima District, Nakhon Ratchasima Province. "A composite cranial and postcranial skeleton comprising premaxilla, maxilla, jugal, surangular, prearticular, articular, vertebrae, manual ungual, ischium, tibia, and pedal phalanx". A carcharodontosaurian theropod
Pseudosuchians Pseudosuchians reported from the Khok Kruat Formation Genus Species Location Material Notes ImagesAtoposauridae indet.IndeterminateLam Pao Reservoir, Ban Noi, Sahatsakhan district, Kalasin province.An isolated lanceolate tooth (PRCMR 282).May be attributable to Theriosuchus.Goniopholididae indet.IndeterminateKhok Pha Suam locality, Ubon Ratchathani province.Complete left mandible (SM2021-1-112). KhoratosuchusK. jintasakuli Ban Saphan Hin, Nakhon Ratchasima province.A partial skull (NNRU-A 1803).A neosuchian crocodylomorph
Pterosaurs Pterosaurs reported from the Khok Kruat Formation Genus Species Location Material Notes Images Anhangueridae Indet.Indeterminate Khok Pha Suam locality, Ubon Ratchathani province. Isolated teeth
Turtles Turtles reported from the Khok Kruat Formation Genus Species Location Material Notes Images KizylkumemysK. khoratensis Ban Saphan Hin and Ban Khok Kruat localities, Nakhon Ratchasima province.Shell material. A carettochelyid turtle ShachemysS. sp.Ban Saphan Hin, Nakhon Ratchasima province.Shell material.A adocid turtle; remains too fragmentary for specific assignment.
Fish
Bony fish Bony fish reported from the Khok Kruat Formation Genus Species LocationMaterial Notes Images Ginglymodi Indet.Indeterminate Khok Pha Suam locality, Ubon Ratchathani province. Scales Two types are known. KhoratamiaK. phattharajaniBan Krok Duean Ha, Nakhon Ratchasima province.Holotype (NRRU-F01020023), paratype (NRRU-F01020024) and a patch of scales (NRRU-F01020025).A amiid fish LanxangichthysL. sp. Khok Pha Suam, Ubon Ratchathani province. A lepisosteiform fish
Cartilaginous fish Cartilaginous fish reported from the Khok Kruat Formation Genus Species Location Material Notes ImagesAcrorhizodusA. khoratensisKhok Pha Suam locality, Ubon Ratchathani province.5 teeth, most of them incomplete.A hybodont sharkHeteroptychodusH. aff. steinmanniKhok Pha Suam locality, Ubon Ratchathani province.20 teeth, most incomplete.A hybodont sharkHybodus?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."Hybodus""H." aequitridentatus Khok Pha Suam locality, Ubon Ratchathani province.A thaiodontid hybodontKhoratodusK. foreyi Khok Pha Suam locality, Ubon Ratchathani province.A thaiodontid hybodont ThaiodusT. ruchae Khok Pha Suam locality, Ubon Ratchathani province.One incomplete tooth. A thaiodontid hybodont
See also List of dinosaur-bearing rock formations
References