Reptiles are a cosmopolitan and diversified group in a wide variety of habitats with extremely dissimilar conditions, but to which they have adapted without any problem. One type of ecosystem in which certain reptiles live is the aquatic environment, some permanently, others intermediately, since they come out on land with some frequency, although they spend much of their time submerged.
Do you want to know the characteristics of marine reptiles? In this article on our site we explain the different types of aquatic reptiles that exist, how they breathe and much more.
Characteristics of aquatic reptiles
Aquatic reptiles are vertebrates that do not belong to a single group, but there are several types with different habits. Some of them are exclusively aquatic, while others are considered semi-aquatic because they spend a large part of their time in the water and a small part on land, such as to lay their eggs, sunbathe or breathe. In this sense, there are no generalized traits for these reptiles, although they do have certain characteristics that we can mention:
- Depending on the type, they can live in fresh or s alt water.
- The greatest diversity of reptiles does not have exclusively aquatic habits.
- Some species manage to dive to great depths, so they can withstand the pressure of the environment.
- In certain cases, limbs have been modified to facilitate locomotion in water through swimming.
- Species of marine reptiles have mechanisms to expel excess s alt through the use of specialized glands that, depending on the group, may be in the mouth, eyes or nose.
- They have a common feature and that is the presence of valvular nostrils, that is, they close in the water.
- Food varies according to the type of aquatic reptile, with some large predators being strictly carnivorous, others omnivorous and some herbivorous.
- In some cases, they have quite marked migratory habits, while in others they remain in the same habitat throughout their lives.
How do aquatic reptiles breathe?
Each group of these animals has a specificity to carry out the respiratory process, however, all aquatic reptiles breathe through lungs, which indicates the need to take air directly from the surface of the water.
Despite the above, thanks to adaptations to the aquatic environment, depending on the species, they can remain submerged in water for more or less time, so that some may even be underwater for hours, since which, as in the case of certain turtles or sea snakes, partially carry out gas exchange through the skin or the cloaca.
Types of aquatic reptiles
According to traditional taxonomy, the class Reptilia is made up of the following orders:
- Testudines (turtles)
- Squamous (snakes, blind shingles, and lizards)
- Crocodilios (crocodiles)
- Sphenodonts (tuatara)
Within the first three we find different types of marine and freshwater reptiles, while the species belonging to the last order are exclusively terrestrial. So, let's get to know some concrete examples of aquatic reptiles:
Turtles
Turtles are a common example of aquatic reptiles, although there are species with exclusively terrestrial habits. These animals are unmistakable due to their peculiar shell, which corresponds to a modification of the rib cage and forms part of their spine and ribs.
Turtles lay their eggs on land, so, for this reason and because of the need to breathe, they do not stay exclusively in the aquatic environment. In general, they are usually omnivorous animals, although in some cases they tend to be more herbivorous in the adult phase. In terms of habitat, there are freshwater and s altwater turtles, so in this group we have both marine and freshwater reptiles. Some examples are found in the following species:
S altwater turtles
- Loggerhead sea turtle (Caretta caretta)
- Green Turtle (Chelonia Mydas)
- hawksbill sea turtle (Eretmochelys imbricate)
Freshwater turtles
- Spotted Turtle (Clemmys guttata)
- Musk Turtle (Sternotherus carinatus)
- Pig-nosed Turtle (Carettochelys insculpta)
Flaky
In the order Squamata we find a great diversity of reptiles, within which there are certain species of snakes with aquatic habits, as well as a kind of iguana; the rest are terrestrial habits.
Starting with aquatic snakes, we have, on the one hand, marine species, many of them poisonous. These animals have adapted to life in this environment without any problem and, on the contrary, they are very limited for life on land. In general, the entire reproductive cycle occurs in the water with certain exceptions, such as the genus Laticauda, which corresponds to oviparous animals and lays its eggs on land. They tend to be predators of other animals that live in the sea.
Some examples of these aquatic reptiles are:
- Beaked Sea Serpent (Enhydrina schistosa)
- Olive Sea Serpent (Aipysurus laevis)
- Yellow-Bellied Sea Snake (Hydrophis platurus)
On the other hand, we also found some species of snakes that have semi-aquatic habits, but in ecosystems freshwater, such as:
- Green Anaconda (Eunectes murinus)
- Arafura snake (Acrochordus arafurae)
- Tentacle Snake (Erpeton tentaculatum)
As we have mentioned, there is also an iguana considered a semi-aquatic reptile, the only one in the group apart from the snakes. It is the marine iguana (Amblyrhynchus cristatus). The species is endemic to Ecuador, specifically to the Galapagos Islands, and enters the sea to feed on algae, which are its food. Otherwise, he spends his time on land. If you are curious about this group of animals, do not miss this other article about the Types of iguanas that exist.
Crocodiles
This group is made up of three families that includes commonly known animals, such as crocodiles (Crocodylidae), alligators and caimans (Alligatoridae) and gaviales (Gavialidae). They all have semi-aquatic habits. Most live in tropical areas, although with certain exceptions found in North America and China. They are carnivorous animals that stalk their prey, which they prey on with speed and strength. They all have a similar body shape, although they vary in size, ranging from 1.5 to about 7 meters in length, so in this group we find giant aquatic reptiles.
Although most inhabit freshwater ecosystems, there are species that tolerate the marine or brackish environment, where they fit in without problems. Their habitats are generally associated with lowlands. Let's know the name of some species of marine and freshwater reptiles belonging to this group:
- Gavial (Gavialis gangeticus)
- Chinese alligator (Alligator sinensis)
- Dwarf caiman (Paleosuchus palpebrosus)
- Orinoco crocodile (Crocodylus intermedia)
- American alligator (Alligator mississippiensis)
- Marine or s altwater crocodile (Crocodylus porosus)
- River crocodile (Crocodylus acutus)
Learn about the different types of crocodiles in this other article.
Prehistoric marine reptiles
Aquatic reptiles have been present on the planet for millions of years, so they have a long evolutionary history. Various prehistoric species have become extinct, but fossil finds have revealed their existence in bodies of water. Some examples of prehistoric aquatic reptiles are:
- Ichthyosaurs: within the group we find the species Temnodontosaurus trigonodon, which lived about 180 million years ago and, although it was a reptile marine, he had the appearance of a dolphin. In this other post we talk in depth about marine dinosaurs.
- Sauropterygian: a group of aquatic reptiles that lived in the Mesozoic Era between 251 and 66 million years ago. Some measure up to 12 meters in length.
- Ectenosaurus: Within this group of reptiles that inhabited prehistoric seas, the species Ectenosaurus everhartorum has been identified, and has been compared anatomically with the gharial.
