Definition of Agnathans. Meaning of Agnathans. Synonyms of Agnathans

- extinct agnathans sported extensive exoskeletons composed of either m****ive, heavy dermal armour or small mineralized scales. Almost all agnathans, including...
- gnathostomes than to the surviving agnathans, known as cyclostomes. Cyclostomes apparently split from other agnathans before the evolution of dentine and...
- A blind fish is a fish without functional eyes. Most blind fish species are found in dark habitats such as the deep ocean, deep river channels and underground...
- have evolved as a region distinct from the medulla by the time the first agnathans appeared, 525 million years ago. Location and topography of pons (animation)...
- of the first reptiles include modern reptiles, mammals and birds; the agnathans have given rise to the jawed vertebrates; the bony fishes have given rise...
- Myllokunmingiidae is a group of very early, jawless prehistoric fish (Agnathans) which lived during the Cambrian period. The Myllokunmingiids are the...
- Rhinopteraspis is an extinct genus of pteraspidid heterostracan agnathan. "Rhinopteraspis cornubica (McCoy), with notes on the classification and evolution...
- developed medulla oblongata. Since these are both very similar to early agnathans, it has been suggested that the medulla evolved in these early fish, approximately...
- (chondrichthyans) have five to seven pairs, and the more basal jawless fish ("agnathans") have up to seven. The Cambrian ancestors of vertebrates no doubt had...
- echinoderms have hearts). 520-480 Ma The first vertebrates ("fish") appear: the Agnathans. They were jawless, had seven pairs of pharyngeal arches like their descendants...