Arandaspis

Arandaspis prionotolepis is an extinct species of jawless fish that lived in the Ordovician 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 Indigenous Australian people, the Aranda (now currently called Arrernte).

Arandaspis Temporal range: Early Ordovician 480–470 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Fossil of Arandaspis prionotolepis from Natural History Museum in London
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Infraphylum:	Agnatha
Class:	†Pteraspidomorpha
Order:	†Arandaspidiformes
Family:	†Arandaspididae
Genus:	†Arandaspis Ritchie & Gilbert-Tomlinson, 1977
Type species
†Arandaspis prionotolepis Ritchie & Gilbert-Tomlinson, 1977
Species[1]
A. prionotolepis Ritchie & Gilbert-Tomlinson, 1977 A. sp. Young, 1997

Description

Life restoration, with trunk morphology based on speculation in Ritchie and Gilbert-Tomlinson (1977) and tail based on Sacabambaspis

Arandaspis is estimated to reach around 12–14 cm (5–6 in) long, with a body covered in rows of knobbly armoured scutes. The front of the body and the head were protected by hard plates with openings for the eyes, nostrils and gills. It probably was a filter-feeder. The morphology of its trunk and tail is unknown.^[2] According to comparisons with other early ostracoderms, it would have lacked paired fins and the caudal fin would be of a simple shape,^[2] although another arandaspid Sacabambaspis had a tail consisting of dorsal and ventral webs and an elongated notochordal lobe.^[3]

See also

• Astraspis
• Sacabambaspis