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...
- 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)...
- 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...
- Rhinopteraspis is an extinct genus of pteraspidid heterostracan agnathan. "Rhinopteraspis cornubica (McCoy), with notes on the classification and evolution...
- 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...
- androgen receptor first appeared in gnathostomes (jawed vertebrates). Agnathans (jawless vertebrates) such as lampreys do not produce testosterone but...
- which then gave way to the Givetian 387.7 Ma. During this time the jawless agnathan fishes began to decline in diversity in freshwater and marine environments...
- all chordates with a cartilage-derived skull (i.e., lampreys, armored agnathans, and gnathostomes), and hagfish. The group represents a subclass within...
- 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...