Melville Island plesiosaur remains (Cretaceous of Canada)

Where: Nunavut, Canada (76.1° N, 109.0° W: paleocoordinates 71.5° N, 20.5° W)

• coordinate stated in text

• local area-level geographic resolution

When: Walker Island Member (Isachsen Formation), Late/Upper Aptian (122.5 - 112.0 Ma)

• Although plesiosaur fossils were found at several sites, all were found within the Walker Island Member of the Isachsen Formation. The majority of the fossils came from two sites, both approximately 10-15 m below the contact with the overlying Christopher Formation, suggesting a latest Aptian age for these finds based on their stratigraphic position.

Environment/lithology: fluvial; lithology not reported

• Fluvial deposits are assigned to the uppermost Walker Island Member

•Ecology of plesiosaur fossils is interpreted as freshwater

Size class: macrofossils

• A large number of vertebrae were recovered, along with several other isolated elements (Supplementary Table 1S). In every case, the fossils were found weathered out of the outcrop, and further searching for a source of any of the fossils was unsuccessful. However, with a single exception, the fossils at each locality appear to come from a single size class, and it seems likely that fossils at each site represent single individuals. Most specimens are highly weathered and fragmented, with all centra missing accessory elements such as ribs and neural arches.

Collection methods: surface (float)

• Much of the material recovered was ex situ,

Primary reference: M. J. Vavrek, B. C. Wilhelm, E. E. Maxwell and H. C. E. Larsson. 2014. Arctic plesiosaurs from the Lower Cretaceous of Melville Island, Nunavut, Canada. Cretaceous Research 50:273-281 [R. Benson/R. Benson]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 157245: authorized by Roger Benson, entered by Roger Benson on 11.06.2014

Creative Commons license: CC BY (attribution)

Taxonomic list

 Sauropterygia - Polycotylidae
Polycotylidae indet. Williston 1908 plesiosaur
NUFV 1981-1989, NUFV 1992-1994, NUFV 1996; all disarticulated postcranial remains