Tulerpeton was an extinct genus of four-limbed vertebrates that lived in the Late Devonian period, about 365 million years ago. It is considered one of the first true tetrapods, meaning that it had limbs with digits and a neck that could lift its head. Tulerpeton was adapted to living in shallow marine waters, where it could breathe air and hunt for prey. It had six fingers and toes on each limb, a feature that was later lost in most tetrapods. Tulerpeton was discovered in the Tula Region of Russia, and is known from a fragmented skull, a pectoral girdle, and parts of the forelimb and hindlimb
Tulerpeton belonged to a group of animals called the Tetrapodomorpha, which includes all the vertebrates that have limbs or are descended from limb-bearing ancestors. The Tetrapodomorpha evolved from lobe-finned fish (Sarcopterygii), which had fleshy fins with bones and muscles. Some of these fish, such as Tiktaalik and Eusthenopteron, became more terrestrial and developed features such as lungs, wrists, and elbows. These are known as the stem-tetrapods, because they are not true tetrapods but are close relatives of them
The true tetrapods are divided into two major groups: the Batrachomorpha and the Reptiliomorpha. The Batrachomorpha includes the modern amphibians (frogs, salamanders, and caecilians) and their extinct relatives, such as Acanthostega and Ichthyostega. These were mostly aquatic or semi-aquatic animals that retained gills and had limbs with many digits. The Reptiliomorpha includes the modern reptiles (including birds) and their extinct relatives, such as Diadectes and Seymouria. These were mostly terrestrial animals that lost their gills and had limbs with fewer digits
The closest living relatives of Tulerpeton
Based on the available fossil evidence and molecular data, the closest living relatives of Tulerpeton are the reptiles. This is because Tulerpeton was more closely related to the Reptiliomorpha than to the Batrachomorpha. Tulerpeton shared some features with the early reptiliomorphs, such as a strengthened limb structure, a disconnected head and pectoral girdle, and a lack of gills. However, Tulerpeton also differed from the reptiliomorphs in some ways, such as having six digits instead of five or fewer. Therefore, Tulerpeton was not a reptile itself, but a sister group to them
The exact position of Tulerpeton within the Reptiliomorpha is still uncertain, as different studies have proposed different relationships among the early tetrapods. Some studies suggest that Tulerpeton was more closely related to the amniotes (the group that includes reptiles and mammals) than to other reptiliomorphs, such as Anthracosaurus and Proterogyrinus. Other studies suggest that Tulerpeton was more closely related to these other reptiliomorphs than to the amniotes. More fossil evidence and genetic analysis are needed to resolve this issue
Conclusion
Tulerpeton was one of the first animals to have limbs with digits and a neck that could lift its head. It lived in shallow marine waters during the Late Devonian period, about 365 million years ago. It belonged to the Tetrapodomorpha, a group of vertebrates that evolved from lobe-finned fish. Among the living tetrapods, the closest relatives of Tulerpeton are the reptiles, which are part of the Reptiliomorpha group. However, Tulerpeton was not a reptile itself, but a sister group to them. The exact position of Tulerpeton within the Reptiliomorpha is still debated by scientists.
