Otavia

{{Short description|Extinct genus of sponges}}

{{Italic title}}

{{Taxobox

| name = Otavia antiqua

| fossil_range = {{Long fossil range|760|550}} (Tonian–Ediacaran)

| image = Otavia antiqua.jpg

| image_caption = Fossil

| image2 = Otavia antiqua 3D reconstruction.jpg

| image2_caption = 3D Reconstruction of Otavia antiqua

| regnum = Animalia

| subregnum = Parazoa

| phylum = Porifera?

| genus = {{Extinct}}Otavia

| genus_authority = (Brain et al., 2012)

| species = {{Extinct}}Otavia antiqua

| binomial = {{Extinct}}Otavia antiqua

| binomial_authority = (Brain et al., 2012)

}}

Otavia antiqua is an ancient sponge-like multicellular organism found in the Otavi Group (the generic name being the namesake) in the Etosha National Park, Namibia. It is claimed to be the oldest animal fossil, being found in rock aged between 760 and 550 million years ago. The oldest Otavia fossils are from the Tonian period, before the Cryogenian glaciations, but the latest found were from the Nama Group rocks of the Ediacaran period.{{cite journal |author1=C. K. 'Bob' Brain |author2=Anthony R. Prave |author3=Karl-Heinz Hoffmann |author4=Anthony E. Fallick |author5=Andre Botha |author6=Donald A. Herd |author7=Craig Sturrock |author8=Iain Young |author9=Daniel J. Condon |author10=Stuart G. Allison |year=2012 |title=The first animals: ca. 760-million-year-old sponge-like fossils from Namibia |journal=South African Journal of Science |volume=108 |issue=1/2 |url=http://www.sajs.co.za/index.php/SAJS/article/view/658/966 |doi=10.4102/sajs.v108i1/2.658|doi-access=free |hdl=2263/18222 |hdl-access=free }}

The shape of Otavia fossils is irregular but rounded, and the size varies from one-third of a millimetre to {{convert|5|mm}}. They are hollow inside, and have many small, osculum-like holes connecting the interior to the outside, similar in body plan to most poriferans. The material of the outer wall is predominantly calcium phosphate.

The affinities of these fossils, along with other paleontological evidence for Precambrian sponges, are disputed.{{cite journal|last1=Antcliffe|first1=Jonathan B.|last2=Callow|first2=Richard H. T.|last3=Brasier|first3=Martin D.|title=Giving the early fossil record of sponges a squeeze|journal=Biological Reviews|date=November 2014|volume=89|issue=4|pages=972–1004|doi=10.1111/brv.12090|pmid=24779547|s2cid=22630754 }}