Nothosaur - Keichosaurus hui
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ITEM # REPTILE-China-0004
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Middle Triassic - 195-230 mya
Guanling Formation
Xingyi, Guizhou Province, China
ITEM # REPTILE-China-0004
Museum-quality example of the reptile Keichosaurus hui. Keichosaurus hui is a member of the Order Nothosauroidea, Family Pachypleurosauridae.
Keichousaurus , like all sauropterygians, was highly adapted to the aquatic environment. individuals of this genus ranged from 15 - 30 cm in length, and had both long necks and long tails, with elongated, five-toed feet. The pointed head and sharp teeth in this genus also indicate that they were fish-eaters. Some recovered specimens feature an especially developed ulna suggesting they may have spent some time on land or in marshes.
This fossil is distinguished by its broad ulna which makes it unlike other European genera. The broad ulna increased the surface area of the forelimbs, making it more effective in locomotion. Keichousaurus shows many characteristics of its family Pachypleurosauridae such as its short snout and elongated temporal openings. Keichousaurus also had a long serpentine neck with a relatively small head and long tail. The anterior caudal vertebrae possess lateral transverse processes. The morphology of Keichousaurus is most like that of Dactylosaurus, showing long and narrow upper temporal openings that extends to the rear of the skull of which is not found in other pachypleurosaurids. Other differences from pachypleurosaurids include Keichousarus' more robust humerus, very broad ulna, and slight hyperphalangy in the manus. The sternum was also lacking in this animal, and the forelimbs were more paddled-shaped, possibly indicating a greater importance of the forelimbs in movement. The pectoral girdle was formed by the paired clavicles, interclavical, scapulae, and coracoids. Keichousaurus was a primitive quadrupedal tetrapod with limbs laterally placed to the body. Different parts of Keichousaurus grew at different rates, a phenomenon called allometric growth.
The locomotion of Keichousaurus probably resembled (in part) the "underwater flight" that plesiosaurs employed. The flattened forelimbs would likely have acted as hydrofoils. The hindlimbs show less specialization, and may therefore have acted as stabilizers and control surfaces, such as is seen in extant sea turtles. The intermediate nature of the limb morphology implies that there was also, to some extent, the kind of 'crawling through the water' seen in small freshwater turtles. The powerfully built pectoral girdle allowed for the attachment of strong muscles, but their location beneath the shoulder favours the underwater flight model. Interestingly, despite the specialization of the limbs, the tail also shows adaptations to an aquatic existence. Lateral transverse processes of the anterior caudal vertebrae show that powerful muscles enabled the tail to beat or at least undulate from side to side. This would imply some distal lateral compression, but this is not recorded in soft-tissue preservation. The long neck was primarily concerned with prey-capture. The combination of powerful limbs and tail would have made K. hui an adept and maneuverable predator.
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 coloration – the result of permineralization 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.
This is a museum-quality example of an adult Keichosaur with all skull features including eye orbits excellently preserved.
This specimen is approximately 10 1/8 long (over 12 inches outstretched) on a matrix measuring 5 1/2 inches by 11 inches.
SORRY, THIS ITEM IS SOLD.
Guanling Formation
Xingyi, Guizhou Province, China
ITEM # REPTILE-China-0004
Museum-quality example of the reptile Keichosaurus hui. Keichosaurus hui is a member of the Order Nothosauroidea, Family Pachypleurosauridae.
Keichousaurus , like all sauropterygians, was highly adapted to the aquatic environment. individuals of this genus ranged from 15 - 30 cm in length, and had both long necks and long tails, with elongated, five-toed feet. The pointed head and sharp teeth in this genus also indicate that they were fish-eaters. Some recovered specimens feature an especially developed ulna suggesting they may have spent some time on land or in marshes.
This fossil is distinguished by its broad ulna which makes it unlike other European genera. The broad ulna increased the surface area of the forelimbs, making it more effective in locomotion. Keichousaurus shows many characteristics of its family Pachypleurosauridae such as its short snout and elongated temporal openings. Keichousaurus also had a long serpentine neck with a relatively small head and long tail. The anterior caudal vertebrae possess lateral transverse processes. The morphology of Keichousaurus is most like that of Dactylosaurus, showing long and narrow upper temporal openings that extends to the rear of the skull of which is not found in other pachypleurosaurids. Other differences from pachypleurosaurids include Keichousarus' more robust humerus, very broad ulna, and slight hyperphalangy in the manus. The sternum was also lacking in this animal, and the forelimbs were more paddled-shaped, possibly indicating a greater importance of the forelimbs in movement. The pectoral girdle was formed by the paired clavicles, interclavical, scapulae, and coracoids. Keichousaurus was a primitive quadrupedal tetrapod with limbs laterally placed to the body. Different parts of Keichousaurus grew at different rates, a phenomenon called allometric growth.
The locomotion of Keichousaurus probably resembled (in part) the "underwater flight" that plesiosaurs employed. The flattened forelimbs would likely have acted as hydrofoils. The hindlimbs show less specialization, and may therefore have acted as stabilizers and control surfaces, such as is seen in extant sea turtles. The intermediate nature of the limb morphology implies that there was also, to some extent, the kind of 'crawling through the water' seen in small freshwater turtles. The powerfully built pectoral girdle allowed for the attachment of strong muscles, but their location beneath the shoulder favours the underwater flight model. Interestingly, despite the specialization of the limbs, the tail also shows adaptations to an aquatic existence. Lateral transverse processes of the anterior caudal vertebrae show that powerful muscles enabled the tail to beat or at least undulate from side to side. This would imply some distal lateral compression, but this is not recorded in soft-tissue preservation. The long neck was primarily concerned with prey-capture. The combination of powerful limbs and tail would have made K. hui an adept and maneuverable predator.
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 coloration – the result of permineralization 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.
This is a museum-quality example of an adult Keichosaur with all skull features including eye orbits excellently preserved.
This specimen is approximately 10 1/8 long (over 12 inches outstretched) on a matrix measuring 5 1/2 inches by 11 inches.
SORRY, THIS ITEM IS SOLD.