Keichousaurus hui

Middle Triassic age, Guanling Formation, Xingyi, Guizhou, China.
Indigenous to China, Keichousaurus hui is commonly discovered within the Triassic deposits of Guizhou Province, China.

These small reptiles, only found in China, once flourished in large populations - thousands swimming in the shallow waters of an intercontinental sea - the species was discovered in 1958.

Their large numbers are indicative that Keichousaurus hui was a prey species, being a valuable food resource for larger predators.

Preserved in a matrix of compacted fine volcanic ash and silt, the slate like matrix in which the fossils are presented, is frequently intersected by natural calcite mineral formations, deposited by water.

Generally preserved with intact articulation, the bones of K. hui present grey to black in colouration – the result of permineralisation whereby inorganic minerals of the surrounding substrate replace organic minerals comprising the delicate bones.

Commonly found with ventral presentation – stomach uppermost – the skull is displayed from beneath – most desirous are dorsal presentations whereby the skull exhibits cranial elements including the large orbits and are particularly sought after by collectors. 

Previously something of an enigma - these fascinating reptiles have only recently (2006) been distinguished according to gender.

The discovery of two specimens preserved carrying unborn babies enabled scientists to differentiate between the acknowledged sexual dimorphism.
Additionally, a second question as to whether the species gave birth to live young, or laid eggs, was answered – babies were delivered (presumably under water) akin to Ichthyosaurs.

Gender differentiation hinges principally upon characteristics of the humerus and ulna, with males having more robust elements.

However, until sexual maturity is reached, gender cannot be determined, so sexing of specimens is restricted to adults.

Maximal maturity peaked at a length of 12” (30cm) approximately, from tip of snout to end of tail – rarely examples are found exceeding this.

Very few life representations of K. hui are available so in 2006, Triassica commissioned paleo artist Gareth Monger to produce a new work, representing the latest understanding of the species morphology.
Triassica own the original artwork – prints available from the Natural History Museum.

Reference to the holotype V952 (Institute of Vertebrate Paleontology & Paleoanthropolgy, Beijing, China) & other described specimens GXD7601,GXD7613, GXD7621, Guizhou Province Museum, China (ref; Functional Morphology & Ontogeny of Keichousaurus hui [Reptilia, Sauropterygia] K. Lin, O. Reippel 1998).

<< Back to fossil information centre