This week, Espen Madsen Knutsen from Natural History Museum, University of Oslo, Norway, will defend his PhD thesis 'Late Jurassic plesiosaurians (Sauropterygia- Plesiosauria) from the Agardhfjellet Formation on Svalbard'.

In his thesis Espen M. Knutsen describes two new genera and five species of plesiosaurians from a marine ecosystem in Svalbard during late jura (145 mill. years ago).

Plesiosaurians were reptiles swimming with four flippers and living 200-65 mill. years ago in the sea. There are not many fossiles of marine reptiles from late jura and the new findings are thus very important for the understanding of the evolution of plesiosaurians as well as their phylogeny.

Four of the species are relatively small animals with a body of 4-5 m length, long necks and small heads. One of the animals has 60 neck vertebras, which is the largest amount registered in a plesiosaurian from the jura until now. The genus of this art is also the first worldwide that shows signs of more than five fingers - a feature until recently believed to be exclusively existing in ichthyosaurians.

Pliosaurians
The fifth species belongs to the subgroup of pliosaurians and is one of the largest of this group found worldwide with a body length of 10-13 m and a head length of 2,5 m. The pliosaurian found in Svalbard has also much longer flippers relative to its body length than any other known large pliosaurian.

The desribed material has been collected in an area in Svalbard that is very rich in fossile marine reptiles. The locality is also of special interest, since its climate, at the time when the animals lived there, was much colder (8-10 ^oC) than is assumed to be suitable for reptiles and future research is needed to investigate the animals adaptations for such a cold climate.

The PhD thesis is part of a larger project at the Natural History Museum in Oslo, describing the marine ecosystem in Svalbard during late jura. Supervisors were Jørn H. Hurum, Patrick S. Druckenmiller, and Hans Arne Nakrem

Read more about the project:
http://www.nhm.uio.no/fakta/zoologi/forhistoriske-dyr/marine-ogler/ (Norwegian only)

Information about the PhD defence:
http://www.nhm.uio.no/forskning/aktuelt/arrangementer/disputaser/2012/knutsen.html (Norwegian only)

Contact: Espen Madsen Knutsen

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Plesiosaur (Illustration: Tor Sponga)

Espen Madsen Knutsen during fieldwork in Svalbard (Photo: Lena Kristiansen)