From Alcoveria Brevis to terrestrial animals. Disclosure 5
Alcoveria brevis corresponds to a fossil of osseous fish, from the group of sarcopterygians, characterised for their lobulated fins, which can be found in the mountains of Alcover (Tarragona) in Southern Europe.
The importance of this fossil lies in two scientific aspects:
-Its appearance in Devonian age (400 millions ago) constitutes a gap between fish and the future terrestrial vertebrates and presents a common ancestor between fish and current amphibious.
-The presence of this fossil in the shores of the current Mediterranean Sea coincides with the current existence of alive sarcopterygian fish in Indic Ocean. If we find out where the current coasts of Mediterranean were between the Carboniferous and the Devonian ages (between 250 and 400 years ago) we can see that those coasts were located where currently the Indic Ocean is (between South Africa, Comoros and Indonesia).
Thus, 400 millions ago, a fish called Alcoveria brevis lived in a zone of the planet which corresponds to the current Comoros. The specimens, which died and got fossil, travelled with the terrestrial plates to their current position but their descendants (Latimeria chalumnae) kept in the same position of the Globe (position in the terrestrial surface in relation to the solar position).
These fossil fish (Alcoveria brevis) had fins with phalanges inside and their evolution (or any of their ancestors) permitted the appearance of hands and arms as we currently know. Therefore we can say that they can be our ancestors or can be related to the ancestors of the human specie.
These sarcopterygian fish have osseous skeleton of endochondral origin. They also have enamel in their jaw and teeth. Their skin is covered by scales and in some extinct species their scales had a layer of cosmine in their surface. In the current species the caudal fin is diphycercal where the vertebrae extend all the way to the end of the tail.
The fins are even and their movement is crossed as in the current terrestrial animals. Their nervous system is also modern by having optical lobes, brain, distinguished cerebellum and their vertebral column reaches the corner of the caudal fin.
Their heart has one venous sine and one arterial sine, two atria and presents a partial division of the ventricle. The circulation also presents 2 circuits: a pulmonary one and an organic one.
In Alcoveria brevis we find an interesting link of the evolution of marine animals to animals that colonised “Tierra Firme”.