Agnathans - Encyclopedia.com
2018年5月29日 · However, many extinct agnathans had extensively developed bony plates directly under the skin. These were most often found in the region of the skull and served as a protective armor. Bony plates are not present in extant agnathan species. Major Groups of Living Agnathans. There are two major groups of living agnathans, the lampreys and the hag ...
Petromyzoniformes (Lampreys) - Encyclopedia.com
Lampreys are scaleless, eel-like fishes that belong to the order Petromyzoniformes. They are jawless vertebrates that are either parasitic or nonparasitic, and have different distributions and habitats depending on their life stage.
Myxiniformes (Hagfishes) - Encyclopedia.com
Hagfishes are the most primitive vertebrates and belong to the order Myxiniformes, the only surviving family of the class Myxini. They have a cartilaginous skeleton, no jaws, and produce slime as a defense mechanism.
Gnathostomata - Encyclopedia.com
2018年5月23日 · *Gnathostomata* *1.* A superclass of jawed vertebrates that includes the fishes, Amphibia [1], Reptilia [2], Aves [3], and Mammalia [4].
Human and Primate Evolution | Encyclopedia.com
Learn about the origins and diversity of humans and other primates, from the Late Cretaceous to the present. The earliest member of our own species are frequently referred to as Homo sapiens, which emerged around 200,000 years ago.
Ordovician Period - Encyclopedia.com
2018年5月17日 · Learn about the Ordovician period, the second period of the Paleozoic era, from 505 to 440 million years ago. Discover the diversity and evolution of marine life, the first primitive fishes, the first land arthropods, and the mass extinction that ended the period.
Lampreys and Hagfishes - Encyclopedia.com
Learn about lampreys and hagfishes, the only living members of the class Agnatha, which are jawless fish with ancient origins. Find out their characteristics, life cycles, interactions with humans, and more.
Hominid - Encyclopedia.com
Hominid is a family of primates that includes humans and their extinct direct ancestors. Learn about the features, fossils, and history of hominids from Australopithecus to Homo sapiens.
Coelacanths and Lungfishes: Sarcopterygii | Encyclopedia.com
COELACANTHS AND LUNGFISHES: SarcopterygiiCOELACANTH (Latimeria chalumnae): SPECIES ACCOUNTSSOUTH AMERICAN LUNGFISH (Lepidosiren paradoxa): SPECIES ACCOUNTSPHYSICAL CHARACTERISTICSCoelacanths (SEE-lah-kanths) and lungfishes have rounded, fleshy fins.
Zoology: Invertebrates Category - Encyclopedia.com
Find facts and information about Zoology: Invertebrates from trusted sources at Encyclopedia.com