SYDNEY, AUSTRALIA- The body mass of two ancient frogs has been determined by an Australian group headed by University of New South Wales Sydney paleontologist Lachlan Hart. The last temnospondyls - amphibians that appear more like crocodiles - went extinct some 120 million years ago, following living on Earth for further to 200 million years.

They have only the fossils to show what a species looked like; therefore, they frequently need to look at current creatures to gain an idea of soft tissue structures, such as fat and skin, thus estimating mass in prehistoric animals presents a difficulty, Mr. Hart explained.

Mr. Hart described temnospondyls as quite weird creatures. Some reached gigantic lengths of six or seven meters. Just like real amphibians, they passed through a larval (tadpole) stage. Many had very broad and round heads, like Australia's Koolasuchus, which was recently declared the Victorian State Fossil Emblem, whereas others, such as the temnospondyls we studied in our study, had more croc-like heads.

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As reported by Mirage, the 1.8-meter-long Eryops megacephalus existed in what is now the United States during the Permian period, whereas the relatively long Paracyclotosaurus davidi thrived in Australia during the Triassic period. The more aquatically oriented Paracyclotosaurus weighed around 260 kilos, whereas Eryops weighed a slightly modest 160 kilogram.

Mr. Hart believes that an animal's size is crucial in many aspects of its life. It affects what they eat, how they exercise, and even the way they deal with frigid weather. Paleontologists are naturally interested in determining the body mass of prehistoric organisms to understand more about how they lived, as stated in the published study in Wiley.

Numerous studies have been conducted on body weight estimation in other ancient animal groups, including such dinosaurs, but not on temnospondyls. These species endured two of Earth's Big Five extinction events, making them a fascinating case study of how animals changed following these global disasters, as emphasized by Mr. Hart.

Paleontologists Unearthed Ancient Amphibian From Cretaceous That Possibly Weighs 260 Kgs.
(Photo: Josè Vitor Silva.)
Paleontologists Unearthed Ancient Amphibian From Cretaceous That Possibly Weighs 260 Kgs. Artist’s reconstruction of Eryops megacephalus (left) and Paracyclotosaurus davidi (right).

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Resembling Today's Giant Amphibians

Because temnospondyls have had no living relatives, the scientists assembled a group of five current 'analogs' including the Chinese Giant Salamander or the Saltwater Crocodile, to evaluate a total of 19 unique body mass estimate approaches for their applicability in temnospondyls.

Dr. Nicolas Campione of the University of New England, Armidale, said they discovered many ways that provided consistently precise body mass assessments in our five living animals, including employing mathematical formulae and 3-dimensional digital representations of the creatures. A body mass estimate expert also participating in the study reasoned that since such strategies work for creatures that live and look like temnospondyls, they should also work for temnospondyls.

Dr. Matthew McCurry, a senior lecturer in Earth Science at UNSW and research co-author, stated that the whole work has demonstrated that there are different ways for determining mass in temnospondyls.

Some ways involve using the breadth of the cranium or the diameter of the legs rather than the entire skeleton. Paleontologists will benefit from the work because many fossils are just one or two skeleton segments.

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