Fossil growth reveals insights into the climate

September 08, 2020

Panthasaurus maleriensis lived about 225 million years ago in what is now India. It is an ancestor of today's amphibians and has been considered the most puzzling representative of the Metoposauridae. Paleontologists from the universities of Bonn (Germany) and Opole (Poland) examined the fossil's bone tissue and compared it with other representatives of the family also dating from the Triassic. They discovered phases of slower and faster growth in the bone, which apparently depended on the climate. The results have now been published in the journal PeerJ.

Temnospondyli belong to the ancestors of today's amphibians. This group of animals became extinct about 120 million years ago in the Early Cretaceous. The Temnospondyli also include the Metoposauridae, a fossil group that lived exclusively in the Late Triassic about 225 million years ago. Remains of these ancestors are present on almost every continent. In Europe, they are found mainly in Poland, Portugal and also in southern Germany.

Panthasaurus maleriensis, the most puzzling representative of the Metoposauridae to date, lived in what is now India, near the town of Boyapally. "Until now, there were hardly any investigation opportunities because the fossils were very difficult to access," explains Elzbieta Teschner from the University of Opole, who is working on her doctorate in paleontology in the research group of Prof. Dr. Martin Sander at the University of Bonn. Researchers from the Universities of Bonn and Opole, together with colleagues from the Indian Statistical Institute in Kolkata (India), have now examined the tissue of fossil bones of a metoposaur from the Southern Hemisphere for the first time. The amphibian, which resembled a crocodile, could grow up to three meters in length.

Valuable insight into the bone interior

"The investigated taxon is called Panthasaurus maleriensis and was found in the Maleri Formation in Central India," notes Teschner with regard to the name. So far, the fossil has only been examined morphologically on the basis of its external shape. "Histology as the study of tissues, on the other hand, provides us with a valuable insight into the bone interior," says Dr. Dorota Konietzko-Meier from the Institute for Geosciences at the University of Bonn. The histological findings can be used to draw conclusions about age, habitat and even climate during the animal's lifetime.

The histological examinations revealed that the young animals had very rapid bone growth and that this growth decreased with age. The Indian site where the bones were found provides evidence of both young and adult animals, in contrast to Krasiejów (south-western Poland), where only young animals were found. Geological and geochemical data show that the Late Triassic consisted of alternating dry and rainy periods, as in the present monsoon climate of India. "This sequence is also reflected in the material examined," says Teschner. "There are phases of rapid growth, known as zones, and a slowdown, known as annulus." Normally, one can still observe stagnation lines in the bones, which develop during unfavorable phases of life, for example during very hot or very cold seasons.

In Panthasaurus maleriensis, however, growth never comes to a complete cessation. In comparison: the Polish Metoposaurus krasiejowensis shows the same alternation of zones and annuli in one life cycle and no stagnation lines, whereas the Moroccan representative of the metoposaurs Dutuitosaurus ouazzoui shows stagnation lines - that is, a complete stop in growth - in each life cycle.

The different growth phases in the bones allow for a comparison of climatic conditions. This means that the climate in the Late Triassic would have been milder in Central India than in Morocco, but not as mild as in the area that today belongs to Poland. Sander: "Fossil bones therefore offer a window into the prehistoric past."
-end-
Publication: Elzbieta M. Teschner, Sanjukta Chakravorti, Dhurjati P. Sengupta, Dorota Konietzko-Meier: Climatic influence on the growth pattern of Panthasaurus maleriensis from the Late Triassic of India deduced from paleohistology, PeerJ, DOI: 10.7717/peerj.9868

University of Bonn

Related Fossil Articles from Brightsurf:

Fossil shark turns in to mystery pterosaur
Lead author of the project, University of Portsmouth PhD student Roy Smith, discovered the mystery creature amongst fossil collections housed in the Sedgwick Museum of Cambridge and the Booth Museum at Brighton that were assembled when phosphate mining was at its peak in the English Fens between 1851 and 1900.

New fossil seal species rewrites history
An international team of biologists, led by Monash University, has discovered a new species of extinct monk seal from the Southern Hemisphere -- describing it as the biggest breakthrough in seal evolution in 70 years.

How to fix the movement for fossil fuel divestment
Bankers and environmentalists alike are increasingly calling for capital markets to play a bigger role in the war on carbon.

New fossil ape is discovered in India
A 13-million-year-old fossil unearthed in northern India comes from a newly discovered ape, the earliest known ancestor of the modern-day gibbon.

Fossil growth reveals insights into the climate
Panthasaurus maleriensis is an ancestor of today's amphibians and has been considered the most puzzling representative of the Metoposauridae.

Australian fossil reveals new plant species
Fresh examination of an Australian fossil -- believed to be among the earliest plants on Earth -- has revealed evidence of a new plant species that existed in Australia more than 359 Million years ago.

Tracking fossil fuel emissions with carbon-14
Researchers from NOAA and the University of Colorado have devised a breakthrough method for estimating national emissions of carbon dioxide from fossil fuels using ambient air samples and a well-known isotope of carbon that scientists have relied on for decades to date archaeological sites.

Rare lizard fossil preserved in amber
The tiny forefoot of a lizard of the genus Anolis was trapped in amber about 15 to 20 million years ago.

Reconstructing the diet of fossil vertebrates
Paleodietary studies of the fossil record are impeded by a lack of reliable and unequivocal tracers.

Fossil is the oldest-known scorpion
Scientists studying fossils collected 35 years ago have identified them as the oldest-known scorpion species, a prehistoric animal from about 437 million years ago.

Read More: Fossil News and Fossil Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.