How Many Sea Turtle Species Exist?

Article In Progress

 To begin, I am not a biologist, not an expert, and I cannot answer this question. Species determination is a very complex process, and much more research is likely needed to answer this question. I only became interested in this topic after photographing Green sea turtles in the Galapagos islands & Hawaii and then comparing them to other Green sea turtles I also witnessed in the North Atlantic (Florida & Costa Rica). In each place in the Pacific that I visited, the behavior was slightly different, the common name was slightly different, and I also noticed slight differences in overall color and carapace shape when compared to the Atlantic turtles. I should also mention that science constantly evolves as new information is obtained. For instance, new species of sharks are added almost monthly as more research is completed.

 As of this writing, the overwhelming consensus is that seven species of sea turtles currently exist worldwide. They are Dermochelys coriacea (Leatherback), Chelonia mydas (Green), Caretta caretta (Loggerhead), Eretmochelys imbricata (Hawksbill), Lepidochelys kempii (Kemps Ridley), Lepidochelys olivacea (Olive Ridley), & from Australia, Natator depressus (Flatback sea turtle).

 When I take photos of an animal, I enjoy using field guides to identify each species. I then catalog each of those species on this website under the scientific name. The Pacific Green sea turtles made me a little confused. The Galapagos Green sea turtle for instance were listed as Chelonia mydas agassizii or Chelonia agassizii. Some people call them Pacific Black Turtles, and I think in Hawaii, they also call them the Black turtles.

 As I was looking over the photos and videos, I could clearly see a difference in the Galapagos sea turtles' shape. In Progress...

Animals separated by continents, ice caps, or the equator may slowly evolve into genetically different species. A good example of this is the right whales. We have three species geographically separated. They are  (Eubalaena glacialis (North Atlantic right whale), Eubalaena australis (Southern right whale), & Eubalaena japonica (North Pacific right whale).

This brings up questions about the other Pacific sea turtle species. The Pacific Leatherback and Loggerhead could also someday become their own separate species.

Links:

Scientists Okamoto and Kamezaki claim the agassizii species:

https://www.researchgate.net/publication/230817454_Chelonia_mydas_agassizii_Black_Pacific_sea_turtle_Epibiont_barnacles

US FIsh & Wildlife: 

https://www.fws.gov/story/eastern-pacific-green-sea-turtle

Pacific turtle migration:

https://seaturtles.org/green-sea-turtle-sanjay-makes-historic-migration/