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The ancient marine predator had a built-in buoy



The ancient marine predator had a built-in buoy

Illustration of a short-tailed dragon. Image credit: Tyler Stone BA ̵

7;19, art and film; see his website tylerstoneart.wordpress.com

About 240 million years ago, when reptiles ruled the ocean, a lizard-like predator floated in shallow water near the bottom of the edge, picking up prey with tooth-like teeth. According to the Journal of vertebrate paleontology.


Paleontologists from the Chinese Academy of Sciences and the Canadian Museum of Nature analyzed two bones in thin limestone layers in two quarries in southwest China. They believe that these bones are non-dinosaurs, Triassic marine reptiles, with small heads, fangs, flippers, long necks, and generally long tails, which are usually used for propulsion. However, in the new species, the tail is short and flat.

“Our analysis of the two well-preserved bones shows that the reptile has a wide mast body (toothed bones) and a very short and flat tail. The long tail can be used to flick in the water to generate thrust, but a new species” It has been found that it may be more suitable for wandering near shallow waters, using its short and flat tail to maintain balance, just like floating underwater objects, which can retain energy while looking for prey,” said Dr. Shang Qinghua. China Academy of Sciences, Beijing.

Scientists named the new species jiyangshanensis, the Latin “brevi” abbreviation is “short”, the Latin “caudo” means “tail”, and the Greek “sauros” means “lizard”. The most complete skeleton of the two was found in the Jiyangshan Quarry, giving the specimen the species name. The length is less than 60 cm.

Ancient marine predator had a built-in float Jiyangshan short-tailed dragon and so on. In November, the skeleton in the back view. A, IVPP V 18625, complete type; B, IVPP V 26010, specimen. Image source: Shanghai Tsinghua University, Wu Xiaochun, Journal of vertebrate paleontology

The skeleton provides more clues to its lifestyle. The forelimbs are more developed than the hind limbs, indicating that they play a role in helping reptiles swim. However, compared with other species, the bones of the forefoot are short, which limits its ability to pull water. Most of its bones, including the vertebrae and ribs, are thick and dense, which further promotes the reptile’s short, sturdy appearance, and limits its ability to swim quickly, but increases underwater stability.

However, thick and high-quality bones can be used as ballast. Reptiles lose speed, but gain stability. Dense bones, called plaque hyperplasia, may make them neutrally buoyant in shallow water. Coupled with a flat tail, this will help the predator to float still underwater and stay level with almost no energy. Neutral buoyancy should also enable it to walk on the ocean floor in search of slow-moving prey.

Highly dense ribs may also indicate large lungs in reptiles. As the lack of firm support for weight implies, non-dinosaurs are nuts in the ocean and they need to enter the water to absorb oxygen. They have nostrils on the nose for breathing. Large lungs will increase the residence time of species underwater.

Ancient marine predator had a built-in float Jiyangshan short-tailed dragon and so on. November 11, IVPP V 18625, photo and outline of the skull and mandible in the back view. A, B, IVPP V 18625, the back is integer C, D, IVPP V 26010, the index book, the nose part of the skull. The zigzag line indicates the broken area. bo, occipital bone; cqp, cranial pass; d, teeth; ec, ectopterygoid; eo, occipital bone; f, frontal lobe; j, law; maxillary n. Nose; op, orthopedic; or orbit p, parietal wall pf, prefrontal lobe; pl,;; pm, front jaw; posterior orbit pof, posterior forehead; pt, pterygoid; q, quadrilateral; qj, quadrilateral; rap, Kyphosis; sa, rectangular; therefore, supraoccipital; square sacred, bone.Image source: Shanghai Tsinghua University, Wu Xiaochunhe Journal of vertebrate paleontology

The middle ear of the new species has a rod-shaped bone called a barbone, which is used to transmit sound. During the preservation process, the fish usually disappear among other dinosaurs or marine reptiles. Scientists have predicted that if a bone is found in non-keel bones, it will be as thin and slender as other species in this branch of the reptile family tree. However, Bifidobacterium Jiyangshan is thick and slender, indicating that it can hear well underwater.

Dr. Wu Xiaochun, a co-author of the Canadian Museum of Nature, said: “Maybe this small, slow-swimming marine reptile must be alert to large predators when floating in shallow water, and is also a predator itself.”


A large number of well-preserved reptiles were found in the belly of prehistoric marine carnivores


More information:
Journal of vertebrate paleontology (2020). www.tandfonline.com/doi/10.108…2724634.2020.1789651

Courtesy of Taylor and Francis

Citation: The ancient marine predator has a built-in buoy (2020, October 28), retrieved from https://phys.org/news/2020-10-ancient-marine-predator-built-in.html to 2020 October Month 29

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