Previous research has pointed to crocodiles and alligators starting with a land-based ancestor some 200 million years ago and then moving to fresh water, becoming the semi-aquatic ambush predators they are today.
But a new analysis, published online today in the journal Scientific Reports, offers a different story. Modern crocodiles and alligators came from a variety of surroundings beginning in the early Jurassic Period, and various species occupied a host of ecosystems over time, including land, estuarine, freshwater
As University of Iowa researcher and study co-author Christopher Brochu says, “Crocodiles are not living fossils. Transitions between land, sea, and freshwater were more frequent than we thought, and the transitions were not always land-to-freshwater or freshwater-to-marine.” Paper. (open access) – Eric W. Wilberg, Alan H. Turner, Christopher A. Brochu. Evolutionary structure and timing of major habitat shifts in Crocodylomorpha. Scientific Reports, 2019; 9 (1) DOI: 10.1038/s41598-018-36795-1
Actually, Dr. Brochu is mistaken. Crocodiles are still “living fossils” because they are largely unchanged over many environments. We think the term “durable species” is a better descriptor for all such species because it evokes the same characteristic—they are largely unchanged over a very long period—but the term is not itself an apparent contradiction in terms.
Essentially, crocodilians are highly adaptable.
See also: Convergent Evolution Of Crocodile And Dolphin Skull Shapes
Crocodile’s eyes fine-tuned for lurking
Someone noticed the alligator’s second jaw joint
Stasis: Life goes on but evolution does not happen
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