Arandaspis

Arandaspis
Life reconstruction of Arandaspis prionotolepis
Fossil of Arandaspis prionotolepis from the Natural History Museum in London
Scientific classification Edit this classification
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
  • †Arandaspis prionotolepis
  • †Arandaspis sp.

Arandaspis is an extinct genus of jawless fish that lived in Australia during the Darriwilian age of the Ordovician period. It contains two species, Arandaspis prionotolepis and Arandaspis sp.

Discovery

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. The discovery of Arandaspis makes it one of the first record of a Ordovician vertebrate from the southern hemisphere.

Arandaspis is named after a local Indigenous Australian people, the Aranda (now currently called Arrernte).

Description

Arandaspis is estimated to reach around 12–14 cm (5–6 in) long. It has 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. According to comparisons with other early ostracoderms, it would have lacked paired fins and the caudal fin would be of a simple shape, although another arandaspid Sacabambaspis had a tail consisting of dorsal and ventral webs and an elongated notochordal lobe.

Species

See also

References

  1. 1 2 Hagiwara, Wahei; Sallan, Lauren (2026-01-09). "Mass extinction triggered the early radiations of jawed vertebrates and their jawless relatives (gnathostomes)". Science Advances. 12 (2) eaeb2297. doi:10.1126/sciadv.aeb2297. PMC 12787538. PMID 41512057.
  2. ↑ "Pteraspidomorphi". Retrieved 28 October 2013.
  3. 1 2 3 4 5 Ritchie, Alexander; Gilbert-Tomlinson, Joyce (1977). "First Ordovician vertebrates from the Southern Hemisphere". Alcheringa: An Australasian Journal of Palaeontology. 1 (4): 351–368. doi:10.1080/03115517708527770. ISSN 0311-5518.
  4. ↑ Pradel, Alan; Sansom, Ivan. J; Gagnier, Pierre-Yves; Cespedes, Ricardo; Janvier, Philippe (2006-11-14). "The tail of the Ordovician fish Sacabambaspis". Biology Letters. 3 (1): 73–76. doi:10.1098/rsbl.2006.0557. ISSN 1744-9561. PMC 2373808.