''Arandaspis prionotolepis'' is an extinct

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

jawless fish Agnatha (, Ancient Greek 'without jaws') is an infraphylum of jawless fish in the phylum Chordata, subphylum Vertebrata, consisting of both present ( cyclostomes) and extinct (conodonts and ostracoderms) species. Among recent animals, cyclosto ...

that lived in the

Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. T ...

period, about 480 to 470 million years ago. Its remains were found in the Stairway Sandstone near Alice Springs, Australia in 1959, but it was not determined that they were the oldest known vertebrates until the late 1960s. ''Arandaspis'' is named after a local Aboriginal tribe, the Aranda (now currently called

Arrernte Arrernte (also spelt Aranda, etc.) is a descriptor related to a group of Aboriginal Australian peoples from Central Australia. It may refer to: * Arrernte (area), land controlled by the Arrernte Council (?) * Arrernte people, Aboriginal Australi ...

Description

''Arandaspis'' was about long, with a streamlined body covered in rows of knobbly armoured

scute A scute or scutum (Latin: ''scutum''; plural: ''scuta'' "shield") is a bony external plate or scale overlaid with horn, as on the shell of a turtle, the skin of crocodilians, and the feet of birds. The term is also used to describe the anterior po ...

s. The front of the body and the head were protected by hard plates with openings for the eyes, nostrils and

gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

s. It probably was a

filter-feeder Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...

. It had no fins; its only method of propulsion was the use of its vertically flattened tail. As a result, it probably swam in a fashion similar to a modern

tadpole A tadpole is the larval stage in the biological life cycle of an amphibian. Most tadpoles are fully aquatic, though some species of amphibians have tadpoles that are terrestrial. Tadpoles have some fish-like features that may not be found ...

References

Pteraspidomorphi genera Ordovician jawless fish Prehistoric fish of Australia Early Ordovician genus first appearances Early Ordovician genus extinctions Fossil taxa described in 1977 {{ordovician-animal-stub

Description

See also

References