2013 -$20 fine silver coin - Canadian Dinosaurs - Bathygnathus borealis

One of the first fossil discoveries to capture the Canadian imagination was that of the Bathygnathus borealis-found in 1845 near New London, Prince Edward Island. It wasn't until 1905 that the bone was correctly identified as part of the upper jaw of a sphenacodontid, a family of “pelycosaur-grade” mammal-like reptiles or synapsids, animals that lived from the Late Pennsylvanian to middle Permian ages. Based on similarities of the jaw bones, experts now believe that the specimen could actually belong to the sail-back Dimetrodon or a similar animal, although fossil evidence of a sail has yet to be found. If Bathygnathus was similar to Dimetrodon, the large “sail” on its back could have helped regulate its body temperature.

Despite its early misidentification, this fossil is of great scientific and historical significance—it lived between 290 and 260 million years ago, when what is now P.E.I. lay near the equator.

Specifications
Mintage 8500
Composition 99.99% fine silver
Finish proof
Weight (g) 31.39
Diameter (mm)38
Edge serrated
Certificate serialized
Face value 20 dollars
Artist Julius Csotonyi (reverse), Susanna Blunt (obverse)