How Many Species of Turtles are There ?

I was recently thinking of getting a new turtle, and I wanted to get a more exotic species, so I started looking up some of those species. During my research I was astonished by how many species of turtles are out there, I always knew that there are a lot of them but I never knew that there were so many. So I decided to write this article to share the results of my research with you.

How many species of turtles are there? There are 318 known turtle species, 104 turtle genera, and 14 turtle families.

Not every turtle biologist will agree to those exact numbers, but this is a common thing in most fields of study, there will always be somebody who doesn’t completely agree with a certain number. But in general 318 is the number that most turtle biologists agree on. But turtles aren’t classified only by species, there is also the classification based on genera and families. If you are not sure what a genre or a turtle family is, don’t worry I will explain it in this article, along with the reason why there are so many turtle species and even more.

What Does Species Mean

The official of species is this:

A group of individuals that can breed with one another, give birth to fertile offspring, and which cannot breed with other groups

The definition seems pretty clear but in the world of taxonomy, which is the branch of biology that is responsible for classifying organisms, the definition above is known as the biological species concept, which means that this is only one of many similar concepts used by taxonomists when they are describing a new species.

So even if the word species has a definition, that definition has many interpretations. This is because Charles Darwin himself didn’t give the word species a clear definition to the word in his book on The Origin of Species. What he said is this:

No one definition of species has as yet satisfied all naturalists; yet every naturalist knows vaguely what he means when he speaks of species

Charles Darwin

A simplified way to adapt what he said is that the word species can’t have an exact definition but everybody knows what you mean when you say species.

The book The Origin of Species was written in 1859, and even today, more than 150 years later we still don’t have an exact definition. This is because it’s impossible to find criteria that can apply to all the things that are living, and have lived on this planet.

In the taxonomic ranking species is in the last place, this means that it’s the most detailed way you can refer to a species.

This is the taxonomic ranking:

Life
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

Some people say that the 10th place should be subspecies, and that is true in some cases. But the fact that not all species have a subspecies isn’t going to work for this classification.

I mentioned that there are multiple species concepts, here is a list of some of the most used ones:

Biological species concept
Cladistic species concept
Cohesion species concept
Competition species concept
Ecological species concept
Evolutionary species concept
Isolation species concept
Morphological species concept
Phylogenetics species concept
Recognition species concept
Typological species concept
Genetic species concept

So to simplify things you can just say that there are different criteria that are used when an animal is assigned to a certain species. And a species is a group of living beings that can reproduce with one another. Even if the word species has multiple definitions you can’t say that one of them applies to all living beings.

Why are There so Many Turtle Species

The reason why there are so many turtle species is that turtles live in almost every place on earth. And to be able to survive in all those different areas they need to adapt, and turtles are very good at that. So for every new habitat, they move to they need to make some changes that allow them to survive in that habitat.

They don’t always have to be huge biological changes, like evolving their legs into flippers. Sometimes just changing the color of their shells can drastically increase their chance of survival in a certain habitat. And a turtle that goes through a change like this basically starts a new species, of course, that only one turtle isn’t enough to start calling it a new species, but over time this characteristic will get passed down to other generations and so a new species is born. So basically a new species is born when an organism evolves.

Here is a simplified way of describing evolution: over lots of generations organisms in one species can build up to random DNA mutations that can help them survive better in a certain area, those mutations are passed down to their children. Eventually, with enough of those helpful mutations, one species can split into two or more species.

There is also the concept of coevolution. Coevolution is the process where two species that live in close vicinity to one another will affect each other’s evolution. So for example, if two different species of turtles, we will call them species A and species B, live in close vicinity near each other. Let’s say that both species are carnivores and they only eat meat. Species A has a better ability to catch prey and they end up eating almost all the meat in the area. Then species B will have to adapt in order to survive, so one possibility is that species B starts changing and splits into two different species, species C and D. Species C becomes completely vegetarian, this way it will have enough food and it won’t have to compete with other species for food since there is enough vegetation in the area. Species D becomes omnivorous, so it will eat all the meat that it can get and in rest, it will eat vegetation. This is one of the many ways a species can influence the way another species evolves.

At some point in time, there were only one turtle species that lived in an area, some of those turtles started developing new characteristics that allowed them to live better in that area. At that point, they basically become another species. And after some time some of those turtles decided to migrate to another area, after some time spent in that area they start to develop new changes and so another species is born. At some point in time, there was a dramatic change in the temperature on the planet, like the Ice Age for example, and some of those turtle species manage to adapt and survive, basically giving birth to a new species and some of them weren’t able to adapt thus becoming extinct. Those are just a few examples of how a turtle managed to be split into so many species.

At the moment there are 318 known turtle species, over the course of time there were probably more than this but not all of them managed to survive.

The reason why turtles need to split into so many species is that compared to other animals there are very few species of turtles that can adapt to a lot of different environments.

So in order to survive in a new and different place, they need to go through changes and become a new species. Some animals are able to adapt to a new place without going through physical changes, others are not able to do so and they need to evolve. Turtles are just the kind that needs to evolve to be able to survive in new places.

Difference Between a Species and a Subspecies

I mentioned before that a subspecies is sometimes placed by some people on the 10th place on the taxonomic ranking, meaning that it’s the most detailed way to refer to a certain organism, but the reason why subspecies aren’t officially in the taxonomic ranking is that not all species are split into subspecies.

A subspecies is a smaller population within a species that share one or more common traits. Usually, a subspecies is at least partially genetically isolated from its parent species, so that interbreeding is less likely to occur, thus encouraging the apparition of a new species.

Sometimes biologists tend to be in favor of “creating” a new species instead of a subspecies, or live things as they are because the subspecies term sometimes only manages to create more confusion than be helpful. But as time goes by things might change on the taxonomic rankings so who knows what will become of the subspecies term.

In general, a subspecies is considered the start of an entirely new species. It will take some time for this to happen, but if that subspecies manages to differentiate itself from the main species it will become a new species.

What are the Differences Between the Turtle Species

Every species has its own different characteristics that make it different from the rest.

For example the colors of their shells. Even if this might seem just a superficial trait, it’s actually very important for them. The color of their shells allows them to better hide from predators. So a species that has flashy colors on their shells won’t be able to survive for long in an environment where there is no vegetation and predators are able to spot them easily because of their colors.

Size is also a very different thing between turtle species. Some turtles have evolved to grow big because this way they can get rid of predators, and other species have evolved to stay small because this way they can hide from predators.

The hardness of the shell is something that can differ from species to species. Even if most turtles have hard shells, some turtles have soft shells, this is because in the environment where they live a softshell is more helpful than a hard one.

Some of them have feet, while some species, like the sea turtles, have flippers.

There are also huge biological differences between turtle species, that are hard to see but they have a huge impact on the way they live.

There are a lot of differences, too many for me to list all of them, but I hope you got a general idea of what kind of differences are between species.

What is a Genera (Genus)

The word genera sound a bit confusing, but in actuality, it’s the plural of the word genus, which is a little more common. But in general, when talking about the classification of animals you will hear the word genera a lot more than genus because there is usually more than one classification.

In the scale of classifications, genus comes above species and family below, this makes it the second most specific way you can refer to an organism.

The standards for genus classification are not very well defined, but in general, the genus of an organism is determined by its ancestors.

There isn’t much I can say about this term, it’s just one way of classifying living beings, shortly I will give you a complete list of the turtle genera and families.

What is a Turtle Family

The term family in this case doesn’t have anything to do with the usual meaning of family, instead, it’s a term used by taxonomists to classify different organisms.

At the moment there are no clearly defined rules that have to be followed when describing or recognizing a family. So I can’t give you any clear answer on how certain species got assigned to a certain family.

Complete List of Turtle Genera and Families

This following taxonomic classification of families and genera is structured after the IUCN ” Turtles of the World” checklist ( Rhodin, VAn Dijk, and Parham 2008 ), with modifications based on Ernest and Bourbour ( 1989 ); Ernest; Lovich, and Barbour ( 1994 ): Bonin, Delvaux, and Dupre ( 2006 ); and Buhlmann, Tuberville, and Gibbons ( 2008 ); and Ernst and Lovich ( 2009 ).

*Subclass Pleurodira*
Family	Genus
Chelide	Acanthochelys
Chelide	Chelodina
Chelide	Chelus
Chelide	Elseya
Chelide	Elusor
Chelide	Emydura
Chelide	Hydromedusa
Chelide	Phrynops
Chelide	Platemys
Chelide	Pseudemydura
Chelide	Rheodytes
Pelomeduside	Pelomedusa
Pelomeduside	Pelusios
Podocnemidae	Erymnochelys
Pelomeduside	Peltocephalus
Pelomeduside	Podocnemis
Pelomeduside	Nilssonia
Pelomeduside	Palea
Pelomeduside	Pelochelys
Pelomeduside	Pelodiscus
Pelomeduside	Rafetus
Pelomeduside	Trionyx
Dermatemydiade	Dermatemys
Kinosternide	Claudis
Kinosternide	Kinosternon
Kinosternide	Staurotypus
Testudinidae	Chersina
Kinosternide	Geochelone
Kinosternide	Gopherus
Kinosternide	Homopus
Kinosternide	Indotesudo
Kinosternide	Kinixys
Kinosternide	Malacobersus
Kinosternide	Manouria
Kinosternide	Psammobates
Kinosternide	Pysix
Kinosternide	Testudo
Emydidae	Actinemys
Emydidae	Chrysemys
Emydidae	Clemmys
Emydidae	Deirochelys
Emydidae	Emydoidea
Emydidae	Emys
Emydidae	Glyptemys
Emydidae	Graptemys
Emydidae	Malaclemys
Emydidae	Pseudemys
Emydidae	Terrapene
Emydidae	Trachemys
Bataguridae	Batagur
Bataguridae	Callagur
Bataguridae	Chinemys
Bataguridae	Cuora
Bataguridae	Cyclemys
Bataguridae	Geoclemys
*Subclass Cryptodira*
Family	Genus
Chelydridae	Chelydra
Chelydridae	Macrochelys
Platysternidae	Platysternon
Cheloniidae	Caretta
Cheloniidae	Chelonia
Cheloniidae	Eretmochelys
Cheloniidae	Lepidochelys
Cheloniidae	Nataor
Dermochelyidae	Dermochelys
Carettochelyidae	Carettochelys
Trionychidae	Amyda
Trionychidae	Apalone
Trionychidae	Aspideretes
Trionychidae	Chitra
Trionychidae	Cyclanorbis
Trionychidae	Cycloderma
Trionychidae	Dogania
Trionychidae	Lissemys
Trionychidae	Geomyda
Trionychidae	Hardella
Trionychidae	Heosemys
Trionychidae	Hieremys
Trionychidae	Kachuga
Trionychidae	Malayemys
Trionychidae	Mauremys
Trionychidae	Melanochelys
Trionychidae	Morenia
Trionychidae	Notochelys
Trionychidae	Ocadia
Trionychidae	Pyxidea
Trionychidae	Rhinoclemmys
Trionychidae	Sacalia
Trionychidae	Siebenrokiella
Geoemydidae	Agrinemis
Geoemydidae	Astrochelys
Geoemydidae	Batrachemys
Geoemydidae	Bufocephala
Geoemydidae	Centrochelys
Geoemydidae	Chelonoidis
Geoemydidae	Cistoclemmys
Geoemydidae	Dipsochelys
Geoemydidae	Leucocephalon
Geoemydidae	Mesoclemmys
Geoemydidae	Oscaria
Geoemydidae	Pangshura
Geoemydidae	Panacephala
Geoemydidae	Rhinemys
Geoemydidae	Strigmochelys

Complete List of Turtle Species

This list is really huge so I’ve written it on a different page so that this article doesn’t become too long. You can find that list right here: Complete List of All Turtle Species.

Conclusion

Now you should know all the important things when it comes to turtle species, how they came to be, and the differences between them.

Things are not very clear when it comes to genus and family, a lot of turtles from one family are more closely related to other turtles from other families than that of their own, and the same thing happens with genera. So at the moment, you shouldn’t try to make sense out of it, not even the people who assign them are probably not 100% sure of how they assign them.

And if at any point during this article you were thinking about the difference between turtles, tortoises, and terrapins, then you should read this article: What is the Difference Between Turtles, Tortoises, and Terrapins?

If you have any questions about turtle species, the difference between them or anything related to turtles in general you should leave them in the comments and I will answer them as soon as possible.