The Superclass Agnatha are of aquatic animals, which have marked the history of life on Earth, as were the first chordates (animals with spinal cord) to evolve.
Their name means "without a jaw," and the only representatives have survived to this day lampreys and Missin.
These two classes have completely changed compared to their ancestors, who had a snake body, could have paired fins or spines that served to stabilize swimming, and had a cephalic shield protecting them from predators (the Pterigoti, scorpions sea). lampreys and Missin gathered in the Superclass Cyclostomes, while their ancestors are part of the class of ostracoderms.
Ostracoderma Example:
http://www.duke.edu/ ~ dwm2/Geology% 20Presentation/Ostracoderms.jpg
Lamprey:
http://www.ittiofauna.org/webmuseum/agnati/petromyzontiformes/petromyzontidae/lampetra/lampetra_fluviatilis/images/l_fluviatilis04-500.jpg
Missin: http://www.seawater.no/ fauna/Fisk/images/DSC00348.jpg
Some lampreys (all rights reserved to the author of the video borjail )
0 comments:
Post a Comment