First Elasmosaur Specimen Found in Alaska
Alaska may be famous for many things, but in palaeontological circles it is the Dinosauria that usually grab the headlines when it comes to the largest and most sparsely populated U.S. State. However, an expedition to the remote Talkeetna Mountains by scientists from the University of Alaska Museum of the North have discovered cervical vertebrae from a large plesiosaurid, an elasmosaur, the first marine reptile of this type to have been discovered in the most northerly part of the USA.
Life in Alaska some Seventy Million Years Ago
Picture credit: James Havens
Elasmosaurus was one of the last and the largest of the long-necked plesiosaurids. During the Late Cretaceous, North America was divided by a huge inland sea (the Western Interior Seaway), elasmosaur fossils have been found in a number of U.S. States as well as in Canada, this new discovery is significant as not only is it the first elasmosaur to be found in Alaska, it supports the theory that large marine reptiles lived at very high latitudes. Although, Late Cretaceous Alaska was much milder than it is today, it would still have been cold with surface sea temperatures dropping to near freezing at times and for much of the year there would have been very little daylight. This isolated fossil discovery provides evidence that large marine reptiles (the specimen is believed to exceed eight metres in length), did indeed live in the far north, and it tantalises palaeontologists who can speculate on whether this creature was a permanent resident or whether elasmosaurs were seasonal migrants.
The most striking feature of the elasmosaurids were their extraordinarily long necks. Approximately, fifty percent of the animal’s entire body length was made up of its neck. These reptiles had over 70 cervical vertebrae, ten times the amount than in the neck of a human being (Homo sapiens). Described back in 1868 from fossil remains found in Kansas, only one species is regarded as valid at the moment, E. platyurus.
The story of the first Alaskan elasmosaurid, began a few years ago. Curvin Metzler a keen, amateur fossil collector who enjoyed hiking and exploring the slopes of the Talkeetna range found several fragments of fossil bone close to a steep hillside. These were the first vertebrate fossils that he had found in the area and knowing that they could represent something important he contacted the Earth Sciences curator at the University of Alaska Museum of the North, Patrick Druckenmiller and persuaded him to visit the location.
Patrick and a couple of colleagues duly visited in June and they were able to follow the bone erosion trail leading back to a section of strata in the hill where a good portion of the skeleton including some beautifully preserved, articulated cervical vertebrae lay exposed.
A Cervical Vertebrae (arrowed) Eroding out of the Surrounding Matrix
Picture credit: Patrick Druckenmiller/additional annotation by Everything Dinosaur
Commenting on his discovery, Mr Metzler stated:
“I’m mostly interested in finding invertebrates, so when I saw the first vertebra I knew it was a bone from something. I didn’t want to disturb anything in the cliff so it was exciting to talk to Pat. We are lucky to have someone in the State who works with fossils.”
Identifying the Last Resting Place of a Marine Reptile
Picture credit: Patrick Druckenmiller
This could represent a new species, but it is too early to tell. Although the team were able to collect a substantial portion of the exposed remains, there is probably more of the fossil specimen buried in the rock face, trouble is, there is more than ten metres of overburden on top and the fossil collecting season this far north is very short.
Undeterred Dr Druckenmiller explained:
“We got a good chunk of the animal but there is still more to excavate.”
A field team will return to the site next summer to complete the extraction work.
Preparing Elasmosaurid Vertebrae in the Field
Picture credit: Patrick Druckenmiller
A spokesperson from Everything Dinosaur outlined the importance of this discovery, explaining that there were a number of Mesozoic aged formations in Alaska, many of which had yielded marine reptiles, but the rocks that had provided marine reptile fossils from this State were much older than the Talkeetna strata.
To read about the discovery of a Triassic marine reptile from Alaska: Thalattosaur discovered in Alaska at Low Tide.
In the press release from the Museum, the strata is estimated to be around 70 million years of age (Maastrichtian faunal stage), whereas, most Elasmosaurus fossils from North America are associated with older Campanian faunal stage deposits.
A Model of an Elasmosaurus
Picture credit: Everything Dinosaur
Many models of Elasmosaurus depict this creature with a flexible, snake-like head. This is inaccurate, Elasmosaurus had a very stiff neck, however, it still was a very effective hunter of fish. The enormous neck enabled it to get up close to shoals before the bulk of the body came into view. The sharp, interlocking teeth made an efficient fish grab.
Recently, Safari Ltd introduced an updated replica of Elasmosaurus, to view this model and others in the Safari Ltd range: Safari Ltd. Prehistoric Animal Models.