Missing Evolutionary Link Found
Studying evolutionary biology is like studying a giant jigsaw puzzle with only half of the pieces in place so far. 150 years ago, Darwin conceived of the puzzle and since then, scientists have gradually been classifying the species in our world in phylogenetic categories. You know how sometimes when you're working on a puzzle, you find one piece that helps you fit in like 30 others? Well that just happened for Natalia Rybczynski and her colleages from the Canadian Museum of Nature. The species they found was named Puijila darwini, or "Darwin's young marine mammal," an apt name considering it fills in an important evolutionary link between modern day seals and walruses and the ancient land mammals they supposedly evolved from.
"We know that some sort of land-dwelling ancestor existed, but how did we get to the fully marine form?" asked Rybczynski, a vertebrate paleontologist with the Canadian Museum of Nature.
Rybczynski's team found the skeleton by accident, while stopping for gas on the way to study an impact crater in the Canadian arctic. They first thought it was a sea otter, but they eventually uncovered an almost complete skeleton and realized it was a new species.
"The remarkably preserved skeleton of Puijila had heavy limbs, indicative of well developed muscles, and flattened phalanges which suggests that the feet were webbed, but not flippers. This animal was likely adept at both swimming and walking on land," said Mary Dawson, curator emeritus of Carnegie Museum of Natural History in Pittsburgh. "For swimming it paddled with both front and hind limbs. Puijila is the evolutionary evidence we have been lacking for so long."
Scientists have not yet placed Puijila in the pinniped family tree, but it seems to have evolved from a common ancestor it shares with seals if it was not a direct ancestor of modern day seals. We finally found another corner piece in the ever-changing puzzle that is biology.