This 11 May 2018 video says about itself:
A 180-million-year-old fossil has revealed an odd creature, a crocodile with a tail like a dolphin, shedding light on the evolution of these ancient animals and how they became some of the greatest predators of the Jurassic period. Researchers are hailing this new species as a “missing link” in the crocodile family tree.
It all began in 1996, when an amateur collector found the fossil on a mountainside in the Gerecse Mountains of north-west Hungary. The specimen was stored at the Hungarian Natural History Museum in Budapest until in 2017, researchers examined it more thoroughly and noticed the odd-looking vertebra on its tail fin.
During the Lower Jurassic, there existed crocodiles that had bony armor on their backs and bellies and had adapted to walk on land. There were also ones that had evolved flippers and had tail fins, but no armor. This fossil, however, appeared to have been both heavily armored and have a tail fin, making it not only a new species, but, according to the researchers, the missing link between the two groups.
Read more here.
From the University of Edinburgh in Scotland:
Jurassic fossil tail tells of missing link in crocodile family tree
May 11, 2018
A 180-million-year-old fossil has shed light on how some ancient crocodiles evolved into dolphin-like animals.
The specimen — featuring a large portion of backbone — represents a missing link in the family tree of crocodiles, and was one of the largest coastal predators of the Jurassic Period, researchers say.
The newly discovered species was nearly five metres long and had large, pointed teeth for grasping prey. It also shared key body features seen in two distinct families of prehistoric crocodiles, the team says.
Some Jurassic-era crocodiles had bony armour on their backs and bellies, and limbs adapted for walking on land. Another group had tail fins and flippers but did not have armour.
The new species was heavily armoured but also had a tail fin, suggesting it is a missing link between the two groups, researchers say.
It has been named Magyarosuchus fitosi in honour of the amateur collector who discovered it, Attila Fitos.
The fossil — unearthed on a mountain range in north-west Hungary in 1996 and stored in a museum in Budapest — was examined by a team of palaeontologists, including a researcher from the University of Edinburgh.
It was identified as a new species based on the discovery of an odd-looking vertebra that formed part of its tail fin.
The study, published in the journal PeerJ, also involved researchers in Hungary and Germany. It was supported by the Leverhulme Trust and the SYNTHESYS project, part of the European Commission’s Seventh Framework Programme.
Dr Mark Young, of the University of Edinburgh’s School of GeoSciences, who was involved in the study, said: “This fossil provides a unique insight into how crocodiles began evolving into dolphin and killer whale-like forms more than 180 million years ago. The presence of both bony armour and a tail fin highlights the remarkable diversity of Jurassic-era crocodiles.”