Reptile reproduction - Types and examples

Content

• reptile classification
• The reproductive evolution of reptiles
• Reptile Egg Characteristics
• Are reptiles oviparous or viviparous?
• Reptile reproduction types
• Examples of reptiles and their reproduction

Currently, the lineage from which reptiles evolved is composed of a group of animals known as amniotes, which developed a fundamental aspect to be able to differentiate themselves completely from those species that depended entirely on water for reproduction.

In this article by PeritoAnimal we will explain everything about the reptile reproduction, so that you know this biological process in these vertebrates. We'll introduce the types that exist and also give some examples. Good reading.

reptile classification

Reptiles are a group about which it is common to find two forms of classification:

• Lineana: in Linana, which is the traditional classification, these animals are considered within the vertebrate subphylum and the Reptilia class.
• Cladistics: in the cladistic classification, which is more current, the term "reptile" is not used, but it generally establishes that the living animals of this group are Lepidosaurs, Testudines and Arcosaurs. The first would be composed of lizards and snakes, among others; the second, turtles; and the third, crocodiles and birds.

Although the term "reptile" is still commonly used, especially for its practicality, it is important to note that its use has been redefined, among other reasons, because it would include birds.

The reproductive evolution of reptiles

Amphibians were the first vertebrates to conquer a semi-terrestrial life thanks to evolutionary development of certain characteristics, such as:

• Well developed legs.
• Transformation of both the sensory and respiratory systems.
• Adaptations of the skeletal system, which can be in terrestrial areas without the need for water to breathe or feed.

However, there is one aspect in which amphibians are still totally dependent on water: their eggs, and later larvae, require a watery environment for their development.

But the lineage that comprises reptiles developed a particular reproductive strategy: the development of an egg with a shell, which allowed the first reptiles to become totally independent of water to carry out their reproductive process. However, some authors believe that reptiles have not eliminated their relationship with a moist environment for egg development, but that these phases would now occur within a series of membranes that cover the embryo and that, in addition to the necessary nutrients, also provide moisture and protection.

Reptile Egg Characteristics

In this sense, the reptile egg is characterized by having these parts:

• Amnion: have a membrane called the amnion, which covers a cavity that is filled with fluid, where the embryo floats. It is also called the amniotic vesicle.
• allantoic: then there is the allantoide, a membranous sac that has a respiratory and waste storage function.
• Chorium: then there is a third membrane called the chorion, through which oxygen and carbon dioxide circulate.
• bark: and finally, the outermost structure, which is the shell, which is porous and has a protective function.

For more information, we encourage you to read this other article on reptile characteristics.

Are reptiles oviparous or viviparous?

The animal world, in addition to being fascinating, is characterized by diversity, which is not only seen in the existence of so many species, but, on the other hand, each group has different characteristics and strategies that guarantee its biological success. In this sense, the reproductive aspect of reptiles becomes quite varied, so that there are no established absolutisms in this process.

Reptiles show a greater diversity of reproductive strategies than other vertebrates, such as:

• Forms of embryonic development.
• Retention of eggs.
• Parthenogenesis.
• Sex determination, which can be linked to genetic or environmental aspects in some cases.

In general, reptiles have two reproductive modes, so that a large number of reptile species are oviparous. females lay eggs, so that the embryo will develop outside the mother's body, while another smaller group is viviparous, so the females will give birth to already-developed offspring.

But there have also been identified cases of reptiles that some scientists call ovoviviparous, although it is also considered by others as a type of viviparism, which is when the development of the embryo takes place inside the mother but does not depend on her for food, which is known as lecytotrophic nutrition.

Reptile reproduction types

The types of reproduction of animals can be considered from several points of view. In this sense, now let's know how the reptile reproduction.

Reptiles have a sexual reproduction, so the male of the species fertilizes the female, so that later embryonic development occurs. However, there are cases where females do not need to be fertilized to carry out the development of an embryo, this is known as parthenogenesis, an event that will give rise to a genetically exact offspring of the mother. The latter case can be seen in some species of geckos, such as the spiny lizard (binoei heteronoty) and in a species of monitor lizards, the peculiar Komodo dragon (Varanus komodoensis).

Another way to consider the types of reptile reproduction is whether fertilization is internal or external. In the case of reptiles, there is always the internal fertilization. Males have a reproductive organ known as the hemipenis, which usually varies from one species to another, but it is found inside the animal and, as in the case of mammals, it emerges or rises at the time of copulation, thus the male introduces it. in the female to fertilize her.

Examples of reptiles and their reproduction

Now let's look at some examples of the different types of reptile reproduction:

• Oviparous reptiles: some snakes like pythons, lizards like the Komodo dragon, turtles and crocodiles.
• ovoviviparous reptiles: a type of chameleon, such as the Trioceros jacksonii species, snakes of the genus Crotalus, known as rattlesnakes, the asp viper (Vipera aspis) and a legless lizard known as the licranço or glass snake (Anguis fragilis).
• Viviparous reptiles: some snakes, such as pythons and some lizards, such as the species Chalcides striatus, commonly known as the tridactyl-legged snake and lizards of the genus Mabuya.

Reptile reproduction is a fascinating area, given the existing variants in the group, which are not restricted to the reproductive types mentioned above, but there are other variations, such as species that, depending on the area where they are located., can be oviparous or viviparous.

An example of this is the viviparous zootoca (Zootoca viviparous), which reproduces oviparaly in the Iberian populations located in the extreme west of Spain, while those in France, the British Isles, Scandinavia, Russia and part of Asia reproduce viviparaly. The same occurs with two species of australian lizards, bougainvilli lyricist and Saiphos equallis, which show different reproductive modes depending on the location.

Reptiles, like the rest of animals, never cease to amaze us with their many adaptive forms that seek to give continuity to the species that make up this group of vertebrates.

If you want to read more articles similar to Reptile reproduction - Types and examples, we recommend that you enter our Curiosities section of the animal world.