{{Short description|Possible very early animal found in ancient rocks}} {{Use dmy dates|date=November 2019}} {{Automatic taxobox | fossil_range = {{fossil range|609|609|Ediacaran, 609 Ma}} | image = Caveasphaera.jpg | taxon = Caveasphaera | authority = }}
'''''Caveasphaera''''' is a multicellular organism found in 609-million-year-old rocks laid down during the Ediacaran period in the Guizhou Province of South China. The organism is not easily defined as an animal or non-animal.<ref name="EA-20191127">{{cite news |author=Chinese Academy of Sciences |title=Researchers say animal-like embryos preceded animal appearance |url=https://www.eurekalert.org/pub_releases/2019-11/caos-rsa112719.php |date=27 November 2019 |work=EurekAlert! |access-date=28 November 2019 |author-link=Chinese Academy of Sciences |archive-date=28 November 2019 |archive-url=https://web.archive.org/web/20191128151859/https://www.eurekalert.org/pub_releases/2019-11/caos-rsa112719.php |url-status=dead }}</ref><ref name="NYT-20191127">{{cite news |last=Zimmer |first=Carl |author-link=Carl Zimmer |title=Is This the First Fossil of an Embryo? - Mysterious 609-million-year-old balls of cells may be the oldest animal embryos — or something else entirely. |url=https://www.nytimes.com/2019/11/27/science/fossil-embryo-paleontology-caveaspharea.html |date=27 November 2019 |work=The New York Times |access-date=28 November 2019 }}</ref><ref name="AB-20191127">{{cite web |title=Animal Embryos Evolved Before Animals |url=http://astrobiology.com/2019/11/animal-embryos-evolved-before-animals.html |date=27 November 2019 |website= Astrobiology Web |access-date=28 November 2019 }}</ref><ref name="CELL-20191216">{{cite journal |author=Yin, Zongjun |display-authors=et al. |title=The Early Ediacaran Caveasphaera Foreshadows the Evolutionary Origin of Animal-like Embryology |url=https://www.cell.com/current-biology/pdfExtended/S0960-9822(19)31429-0 |date=16 December 2019 |journal=Current Biology |volume=29 |issue=24 |pages=4307–4314.e2 |doi=10.1016/j.cub.2019.10.057 |pmid=31786065 |s2cid=208332041 |access-date=28 November 2019 |doi-access=free |hdl=1983/13fb76e4-5d57-4e39-b222-14f8a8fae303 |hdl-access=free }}</ref><ref name="SN-20191128">{{cite news |author=Staff |title=Animal-Like Embryos Evolved Long Before Complex Animals, Scientists Say |url=http://www.sci-news.com/biology/caveasphaera-animal-like-embryos-07850.html |date=28 November 2019 |work=Sci-News.com |access-date=28 November 2019 }}</ref> The organism is notable due to the study of related embryonic fossils (measuring about a half-millimeter in diameter)<ref name="EA-20191127" /> which display different stages of its development: from early single-cell stages to later multicellular stages.<ref name="EA-20191127" /><ref name="NYT-20191127" /><ref name="AB-20191127" /><ref name="CELL-20191216" /> Such fossil studies present the earliest evidence of an essential step in animal evolution – the ability to develop distinct tissue layers and organs.<ref name="EA-20191127" /> According to researchers, fossil studies of ''Caveasphaera'' have suggested that animal-like embryonic development arose much earlier than the oldest clearly defined animal fossils<ref name="EA-20191127" /> and may be consistent with studies suggesting that animal evolution may have begun about 750 million years ago.<ref name="NYT-20191127" /><ref name="BE-20161205">{{cite journal |author=Cunningham, John A. |display-authors=et al. |title=The origin of animals: Can molecular clocks and the fossil record be reconciled? |date=5 December 2016 |journal=BioEssays |volume=39 |issue=1 |article-number=e201600120 |doi=10.1002/bies.201600120 |pmid=27918074 |doi-access=free }}</ref> Nonetheless, ''Caveasphaera'' fossils may look similar to starfish and coral embryos.<ref name="EA-20191127" /> Still, researchers have concluded, "Parental investment in the embryonic development of ''Caveasphaera'' and co-occurring ''Tianzhushania'' and ''Spiralicellula'', as well as delayed onset of later development, may reflect an adaptation to the heterogeneous nature of the early Ediacaran nearshore marine environments in which early animals evolved."<ref name="CELL-20191216" />
==References== {{Reflist|colwidth=30em}} {{Taxonbar|from=Q85751043}} Category:Enigmatic eukaryote taxa Category:Tree of life (biology) Category:Ediacaran life