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...
- 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...
- 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...
- then gave way to the Givetian at 387.95 Ma. During this time, the jawless agnathan fishes began to decline in diversity in freshwater and marine environments...
- 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)...
- Diplograptina making their appearance. One of the earliest known armoured agnathan ("ostracoderm") vertebrates, Arandaspis, dates from the Middle Ordovician...
- Late Silurian of Canada, Norway, and the U.S. Tujiaaspis is a galeaspid agnathan from the early Silurian (Telychian) of China, showing origin of paired...
- androgen receptor first appeared in gnathostomes (jawed vertebrates). Agnathans (jawless vertebrates) such as lampreys do not produce testosterone but...