Nanxiong Formation

The Nanxiong Formation (also known as Yuanpu Formation) is a Late Cretaceous geologic formation in Guangdong Province. Dinosaur remains are among the fossils that have been recovered from the formation.

Nanxiong Formation
Stratigraphic range: Maastrichtian 66.7 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Type	Geological formation
Underlies	Shanghu Formation
Overlies	Jurassic granite basement, Changba Formation (Nanxiong Group)
Thickness	~300 m (980 ft) Several kilometers (Nanxiong Group)
Lithology
Primary	Sandstone, siltstone, mudstone
Other	Limestone, conglomerate
Location
Coordinates	23.5°N 114.9°E / 23.5; 114.9
Approximate paleocoordinates	23.8°N 110.5°E / 23.8; 110.5
Region	Guangdong Province
Country	China
Extent	Nanxiong Basin
Nanxiong Formation (China) Show map of China Nanxiong Formation (Guangdong) Show map of Guangdong

Description

It consists of continental siliciclastic red beds, with fauna which similar to that of the Nemegt Formation. It has been dated to about 66.7 ± 0.3 million years ago.^[1] It is the lowest unit of the Nanxiong Basin, a small graben created during Mesozoic rifting.^[2] Buck et al. state that it overlies Jurassic granite basement, and is conformably overlain by the Shanghu Formation.^[1] Alternative stratigraphic schemes for the Nanxiong basin have been proposed,^[3] one of which refers to the Nanxiong succession as the Nanxiong Group, and dividing it into the Yuanpu, Zhutian and Zhenshui formations, and overlying the Albian to Turonian Changba Formation.^[4]

Saline lakes in the Nanxiong were temporary

The Depositional environment is made up of alluvial fan facies consisting of sheetflood deposits and ephemeral braided rivers. Adjacent to these are ephemeral saline playa facies recording features such as; root traces, desiccation cracks, and calcareous paleosols. In situ desert varnish and minor paleosol development on alluvial facies due to inactivity are indicative of arid conditions. Stable carbon and oxygen isotopes from Dinosaur eggshells were used to estimate a mean annual temperature between 22–27.6 °C (71.6–81.7 °F), with positive isotope perturbations around the K/Pg boundary indicating periods where temperatures may have exceeded 27 °C (81 °F).^[5][6][1]

Paleobiota of the Nanxiong Formation

Color key Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon		Notes Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Crocodilians

Crocodilians
Genus	Species	Material	Notes	Images
Jiangxisuchus[7]	J. nankangensis	Nearly complete skull and mandible	A crocodyloid

Lizards

Lizards
Genus	Species	Material	Notes	Images
Chianghsia[8]	C. nankangensis	A partial skull and lower jaws	A monstersaurian lizard
Tianyusaurus[9]	T. zhengi	A skull, mandible, first eight cervical vertebrae and nearly complete pectoral girdles	A polyglyphanodontian lizard, also known from the Qiupa Formation

Turtles

Turtles
Genus	Species	Material	Notes	Images
Jiangxichelys[10]	J. ganzhouensis	A complete shell	A nanhsiungchelyid turtle
Nanhsiungchelys[11]	N. wuchingensis	A partial skeleton	A nanhsiungchelyid turtle[12]
Oolithes[13][12]	O. elongatus, O. nanhsiungensis, O. rugustus and O. spheroides.	Egg and egg clutches. Some of these were probably laid by Nanhsiungchelys.[13][12]	Turtle and/or theropod eggs

Dinosaurs

Ornithischians

Hadrosaurs

Hadrosaurs of the Nanxiong Formation
Genus	Species	Material	Notes	Images
Microhadrosaurus[13]	M. nanshiungensis	Partial lower jaw from a juvenile that was about 2.6 m long	A nomen dubium hadrosaur taxon.[4]
Hadrosauropodus isp.[4]	Indeterminate	Three-toed footprints[4]	A hadrosaur

Sauropods

Sauropods of the Nanxiong Formation
Genus	Species	Material	Notes	Images
Gannansaurus[14]	G. sinensis	A single, nearly complete dorsal vertebra and a mid-caudal vertebra	A sauropod closely related to Euhelopus
Jiangxititan[15]	J. ganzhouensis	The three posteriormost cervical vertebrae with two cervical ribs, articulated with the first four dorsal vertebrae with three dorsal ribs	A somphospondylan of controversial affinities; originally described as a derived lognkosaurian titanosaur, later analyses recovered a more basal, non-titanosaurian position more likely.[16]

Theropods

Oviraptorosaurs

Oviraptorosaurs of the Nanxiong Formation
Genus	Species	Material	Notes	Images
Banji[17]	B. long	Nearly complete skull and lower jaw	An oviraptorid
Corythoraptor[18]	C. jacobsi	Nearly complete skeleton including the skull and lower jaw	An oviraptorid with a distinct cassowary-like crest
Elongatoolithidae indet.	Indeterminate	Three eggs with embryonic remains.[19]	Oviraptorid eggs
Ganzhousaurus[20]	G. nankangensis	Lower jaw, leg bone, hip bone and caudal vertebrae	A transitional oviraptorid with both basal and derived traits
Huanansaurus[21]	H. ganzhouensis	Nearly complete skull, lower jaws, neck vertebrae, a humerus, arm fragments, lower part of the right thighbone, the upper part of the right shinbone, and parts of the right foot	An oviraptorid
Jiangxisaurus[22]	J. ganzhouensis	Incomplete skull, lower jaw, vertebrae, nearly complete pectoral girdle, the left forelimb, ribs, and a partially preserved pelvic girdle	An oviraptorid
Macroolithus	Indeterminate	Five egg clutches containing over 60 eggs.[23]	Oviraptorid eggs
	Indeterminate	Three eggs with embryonic remains.[24]	Oviraptorid eggs
	M. yaotunensis	Two eggs with embryonic remains.[25]	Oviraptorid eggs. Skeletal proportions resemble Heyuannia huangi
	M. yaotunensis	A nest of 24 eggs associated with an adult oviraptorid.[26]	Oviraptorid eggs
Nankangia[27]	N. jiangxiensis	A partial lower jaw, vertebrae, both scapulocoracoids, a nearly complete right humerus, pubic bones, and some dorsal ribs	An oviraptorid
Oviraptoridae indet.	Indeterminate	A female individual preserving the pelvic girdle, some caudals and two eggs inside the abdominal cavity.[28]	A pregnant oviraptorid
	Indeterminate	A nesting adult over a nest of eggs, preserving cervical vertebrae, arms and the pelvic region.[26]	An oviraptorid that represents the fifth nesting taxon
	Indeterminate	A female individual preserving a partial pelvic girdle, hindlimbs and some caudals with two eggs associated near the pelvic region.[29]	A pregnant oviraptorid
Shixinggia[30]	S. oblita	Sparse postcranial remains lacking the skull	An oviraptorid
Tongtianlong[31]	T. limosus	Almost complete skeleton, portions of the arms, right leg, and tail were destroyed by TNT blasts	An oviraptorid, the pose indicates that it may have died trying to free itself from mud

Therizinosaurs

Therizinosaurs of the Nanxiong Formation
Genus	Species	Material	Notes	Images
Nanshiungosaurus	N. brevispinus	Eleven cervical vertebrae, ten dorsal vertebrae, six sacral vertebrae and the pelvis.[13][32]	A therizinosaurid

Tyrannosaurs

Tyrannosaurs of the Nanxiong Formation
Genus	Species	Material	Notes	Images
Asiatyrannus[33]	A. xui	A skull, partial legs, and fragmentary caudal vertebrae	A small-bodied tyrannosaurine
Qianzhousaurus[34]	Q. sinensis	A skull, lower jaw, vertebrae, both scapulocoracoids, a left femur and a left tibia	A tyrannosaurid, could represent a third species of Alioramus[35]
Tyrannosauridae indet.	Indeterminate	Two isolated teeth.[13]	A tyrannosaurid
	Indeterminate	Large and well-preserved tooth.[36]	A tyrannosaurid

Other Theropods

Genus	Species	Material	Notes	Images
Theropoda indet.	Indeterminate	A maxillary tooth that differs from tyrannosaurid and carcharodontosaurid dentition.[36]	A notably large theropod
	Indeterminate	Isolated dorsal vertebra.[13]	A theropod

See also

• List of dinosaur-bearing rock formations
• Dalangshan Formation