7

Here's a question from my son I've found interesting enough to ask here. There are plenty examples of species returning back to the water environment, like dolphins, sea lions, walruses, some snakes, crocodiles etc.

The question is - are there any evidences that in evolution of certain species there was return to the land twice, that is, they've came from sea, then evolve as land species, then, again, evolved to somewhat marine or fresh-water and, finally, turn into land species again?

UPD Chordate are the most interesting but any example, even plants, would be nice.

shabunc
  • 173
  • 7
  • What you describe in the last sentence is "returning to the water", not "returning to the land twice". What you mean is "water -> land -> water -> land", right? – Remi.b Jan 03 '18 at 14:44
  • Related: Has any flying creature evolved into a sea creature? – Remi.b Jan 03 '18 at 14:55
  • Are you interested exclusively in animals? Note that the absence of a clear definition of what is a "water species" and a "land species" might make it hard to answer. – Remi.b Jan 03 '18 at 14:57
  • I am sure that there are no animals that have gone from land to water, and then back to land. I am not sure about plants though. The transition to land is a very difficult one. By the way, I would not say "returning to land twice", because they would only be "returning" once. – Karl Kjer Jan 03 '18 at 17:22
  • @KarlKjer Are you that sure. How about woodlice? Outside of animals, there are probably plenty of examples, esp. if we include prokaryotes but then again the question what it is to be a "land species" and a "water species" will matter – Remi.b Jan 03 '18 at 17:51
  • 1
    Yes, I am sure. Crustacians and Chelicerates evolved in water. I know that woodlice are both terrestrial and aquatic, but that does not necessarily mean the the aquatic species did not move onto land. – Karl Kjer Jan 04 '18 at 01:43
  • Crustaceans are paraphyletic, with insects nested inside them. The sister taxon to Hexapods is likely Remipedia, which are crustaceans that live in freshwater caves. So proto-hexapods evolved entirely on land. Not sure where myriapods evolved, but I would presume in water, because they are deeper on the tree than Hexapods. – Karl Kjer Jan 04 '18 at 01:46
  • Echidna is a good example, they came from platypus type ancestors aprox. 14-20 million years ago. – jack Jul 02 '21 at 03:38
  • You list crocodilians as an example of animals returned to the water. If so, there are extinct crocodilians such as Krabisuchus and Trilophosuchus that may have been more terrestrial, and would nominally be valid answers. That said, crocodilians are too amphibious to find much satisfaction from answering this way. – Mike Serfas Jul 02 '21 at 20:04

2 Answers2

5

Woodlouse

Life emerged in the water. Ancestors of insects, spiders, myriapods and crustaceans were probably terrestrial (please correct me if that is wrong) but then, crustaceans evolved to living in the water again. Finally, woodlice went back onto land!

Remi.b
  • 68,088
  • 11
  • 141
  • 234
2

Echidna come from platypus like ancestors about 14-20 mil years ago. so they count if platypus count as returning to water although not 100% of there like cycle.

brick
  • 21
  • 1