Research on fossilized fish from the late Devonian period, roughly 375 million years ago, details the evolution of fins as they began to transition into limbs fit for walking on land.
How Fish Fins Evolved Just Before the Transition to Land
December 29, 2019
Written By Matt Wood
Research on fossilized fish from the late Devonian period, roughly 375 million years ago, details the evolution of fins as they began to transition into limbs fit for walking on land.
The new study by paleontologists from the University of Chicago, published this week in the Proceedings of the National Academy of Sciences, uses CT scanning to examine the shape and structure of fin rays while still encased in surrounding rock. The imaging tools allowed the researchers to construct digital 3D models of the entire fin of the fishapod Tiktaalik roseae and its relatives in the fossil record for the first time. They could then use these models to infer how the fins worked and changed as they evolved into limbs.
Tiktaalik roseae is remarkably well preserved for a 375-million-year old fossil
Much of the research on fins during this key transitional stage focuses on the large, distinct bones and pieces of cartilage that correspond to those of our upper arm, forearm, wrist, and digits. Known as the “endoskeleton,” researchers trace how these bones changed to become recognizable arms, legs and fingers in tetrapods, or four-legged creatures.