Phu Kradung Formation
Introduction The Early Cretaceous '''Phu Kradung Formation''' is the lowest member of the Mesozoic Khorat Group which outcrops on the Khorat Plateau in Isan, Thailand. This geological formation consists of micaceous, brown to reddish-brown siltstone beds with minor brown and grey shale and sandstone beds. Occasional lime-noduled conglomerate occurs. The Phu Kradung Formation sediments were deposited in a lake-dominated floodplain cut by meandering and occasionally braided river channels.The Phu Kradung Formation is considered, on the basis of recent vertebrae fossil discoveries, to be Late Jurassic in age. However, new palynology and biostratigraphic data suggests an age of Early Cretaceous for the upper section.Dinosaur remains have been recovered from this formation, although none have yet been referred to a specific genus. ''Chalawan'', an extinct genus of pholidosaurid mesoeucrocodylian, is currently known solely from its holotype, a nearly complete mandible collected in the early 1980s from a road-cut near the town of Nong Bua Lamphu in the upper part of the Phu Kradung Formation. This single specimen is the most well preserved vertebrate fossil that has been found from the formation. It contains a single species, ''Chalawan thailandicus''.
Fossil content ===Amphibians=== '''Amphibians reported from the Phu Kradung Formation''' Genus  Species  Presence '''Material''' Notes  ImagesBrachyopidae indet.Phu Noi locality, Kham Muang district, Kalasin province.Posterior part of the skull (KS34-1481) and two intercentra (KS34-1474 and KS34-1489). Brachyopoidea indet.Intercentra (TF 3328, TF 3329, and TF 3144).Also found in the Klong Min Formation.Khao Wong locality, Khao Wong district, Kalasin province.Intercentrum (KS37-8).===Reptiles=======Dinosaurs==== '''Dinosaurs reported from the Phu Kradung Formation''' Genus  Species  Presence '''Material''' Notes  ImagesMamenchisauridae indet.Kalasin province. "Isolated posterior cervical vertebra"Metriacanthosaurinae indet. "a nearly complete left tibia"Metriacanthosaurinae indet. "Skull elements such as teeth, premaxillae, and maxillae as well as appendicular materials of more than one individual."''Minimocursor''''M. phunoiensis''Phu Noi, Kalasin province.Partial articulated skeleton, isolated lower jaw & left leg.A basal neornithischian.Stegosauridae indet. "Single dorsal vertebra".Informally known as "Siamodracon altispinus".====Pseudosuchians==== '''Pseudosuchians reported from the Phu Kradung Formation''' Genus  Species  Presence '''Material''' Notes  Images ''Chalawan''''C. thailandicus'' Mandible.A pholidosaurid.150 px''Indosinosuchus''''I. kalasinensis''A teleosaurid.150 px''I. potamosiamensis''Skulls and postcrania.A teleosaurid.150 px''Sunosuchus''''S. thailandicus''A mandible.Reassigned to ''Chalawan''.Cf. ''Theriosuchus''Cf. ''T.'' sp.Chong Chat, Nong Bua Lamphu province.Part of a left dentary (CCC-1) and a lanceolate tooth (PRCMR 283).An atoposaurid.====Pterosaurs==== '''Pterosaurs reported from the Phu Kradung Formation''' Genus  Species  Presence '''Material''' Notes  Images Rhamphorhynchidae indet. Humerus. Originally identified as an azhdarchid. ====Turtles==== '''Turtles reported from the Phu Kradung Formation''' Genus  Species  Presence '''Material''' Notes  Images''Basilochelys''''B. macrobios''Kham Phok, Mukdahan Province.A trionychoid. Eucryptodira indet.''Kalasinemys''''K. prasarttongosothi''Phu Noi locality, Kalasin Province.Skull and shell material.A xinjiangchelyid.''Phunoichelys''''P. thirakhupti''Phu Noi locality, Kalasin Province.Shell remains.A xinjiangchelyid.''Yakemys''''Y. multiporcata''Khorat Plateau.Shell elements.A macrobaenid.150 px===Fish=======Bony fish==== '''Bony fish reported from the Phu Kradung Formation''' Genus  Species  Presence '''Material''' Notes  Images''Ferganoceratodus''''F. annekempae''Phu Noi.A lungfish.''Isanichthys''''I. lertboosi'' Phu Noi locality, Kalasin province.4 specimens. A lepisosteiform.''I. palustris''A single, nearly complete specimen.A lepisosteiform.''Khoratichthys''''K. gibbus''"Impression of a single articulated fish".A ginglymodian.''Thaiichthys''''T. buddhabutrensis''Phu Nam Jun, Kalasin Province.A lepisosteiform.====Cartilaginous fish====Multiple fin spines have been found in the Phu Kradung Formation which cannot be precisely identified. '''Cartilaginous fish reported from the Phu Kradung Formation''' Genus  Species  Presence '''Material''' Notes  Images''Acrodus''''A. kalasinensis''Kalasin province.Teeth.A hybodontiform.''Heteroptychodus''''H.'' cf. ''H. kokutensis''One almost complete tooth and 20 fragmentary crowns. ?HybodontidaeDermal denticles of 2 morphotypes.A hybodontid.''Hybodus''aff. ''H.'' sp. "One almost complete anterior crown (SM2012-1-004) and a complete posterior tooth (SM2012-1-005)".''H.'' sp.Teeth. "Similar to the teeth of ''H. huangnidanensis'' (which is probably a junior synonym of ''H. antingensis'')".''Jiaodontus''''J.'' sp.10 teeth.A hybodontiform.''Lonchidion''''L.'' sp. ASM2012-1-015-6 and 12 crowns.A hybodontiform.''L.'' sp. BTeeth and crowns.A hybodontiform.===Plants=== '''Plants reported from the Phu Kradung Formation''' Genus  Species  Presence '''Material''' Notes  Images ''Xenoxylon''''X. phyllocladoides'' Fossil wood.
See also * Lists of dinosaur-bearing stratigraphic units** List of stratigraphic units with indeterminate dinosaur fossils
References