by Elizabeth Gamillo/Smithsonianmag.com
Crocodiles are large reptiles with scaly complexions and menacing marble-like eyes. If we were to go back in time 200 million years, we would find that the crocodile’s appearance would be unchanged. Today, there are only 25 different crocodile species, a stark difference in diversity compared to birds, which appeared on the fossil record millions of years after crocodiles did but have since evolved into 10,000 other species.
In a study published this month in Communications Biology, researchers of the University of Bristol found crocodiles have kept their distinct features over millions of years and lack diversity because of punctuated equilibrium, or long periods where species are stable. During these eras, the need to evolve only arises when the animal’s environment forces them to adapt to new conditions, writes Max T. Stockdale, an expert in vertebrae macroevolution and paleontology and who was involved in the study, in the Conversation.
Fossil remains of crocodiles from as early as the Jurassic period show identifying characteristics in modern crocodiles. They both have lengthy snouts, husky tails, and rough, scaly hides. Stockdale and his team used an evolutionary mathematical model to analyze….Read More: