{{Short description|Ediacaran fossil}} {{More citations needed|date=October 2024}} {{Speciesbox | fossil_range = Late Ediacaran<br />~{{fossil range|551|541}} | genus = Curviacus | parent_authority = Shen et al., 2017 | species = ediacaranus | authority = Shen et al., 2017 | display_parents = 3 }} '''''Curviacus''''' is a genus of Ediacaran organism of uncertain lineage that displays a modular body plan consisting of crescent-shaped chambers. It contains a single species, '''''Curviacus ediacaranus'''''.
== Etymology == The genus name ''Curviacus'' references the shape of the crescent chambers; coming from Latin ''curvus'' meaning curved and ''acus'' meaning needle.<ref name="Bing_Shen_2017">{{cite journal |author1=Shen, B. |author2=Xiao, S. |author3=Zhou, C. |author4=Dong, L. |author5=Chang, J. |author6=Chen, Z. |year=2017 |title=A new modular palaeopascichnid fossil ''Curviacus ediacaranus'' new genus and species from the Ediacaran Dengying Formation in the Yangtze Gorges area of South China |journal=Geological Magazine |volume=154 |issue=6 |pages=1257–1268 |doi=10.1017/S001675681700036X|bibcode=2017GeoM..154.1257S |s2cid=131980880 }}</ref>
== Description == These fossils occur on bituminous limestone on the bedding surface. The fossilized specimen has calcispar walls with the inner chambers filled with micrite.<ref name="Bing_Shen_2017" /> The walls are raised because the calcispar does not erode as easily. ''C. ediacaranus'' is a slightly oblong macrofossil that ranges from 5–14 cm in length. It is characterized by its curved or crescent-shaped chambers that occur arranged in a series with the chambers sharing walls. All of the chambers are convex in the same direction. Each chamber is narrow ranging ~1-3mm in width. Chamber length can be consistent or inconsistent. Inconsistencies can give a false impression of branching.<ref name="Bing_Shen_2017" /> Additionally, the walls of the chambers sometimes converge laterally.
==Phylogeny== The phylogeny of this fossil is not yet known. Some scientists believe the genus to be a coralline algal or fungal stem group.<ref name="Bing_Shen_2017" />
== Occurrence == ''C. ediacaranus'' is from the late Ediacaran. The fossil ''C. ediacaranus'' has been found in the Shibantan Member of the Dengying Formation.<ref name="Bing_Shen_2017" /> The Shibantan Member is the bituminous limestone section of the formation.<ref name="ZhouXiao2006">{{cite journal |last1=Zhou |first1=Chuanming |last2=Xiao |first2=Shuhai |date=2006 |title=Ediacaran .δ13C chemostratigraphy of South China |journal=Chemical Geology |volume=237 |issue=1–2 |pages=89–108 |doi=10.1016/j.chemgeo.2006.06.021}}</ref> It is unusual for Ediacaran biota to be preserved in limestone. As such, ''C. ediacaranus'' is the only ''Palaeopascichnus'' fossil to be reported from carbonate rock rather than siliclastic rock.<ref name="Bing_Shen_2017" /> This special type of fossilization allows for 3-dimensional analysis.<ref name="Bing_Shen_2017" />
== References == {{Reflist}}
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{{Improve categories|date=October 2024}}
Category:Ediacaran life Category:Incertae sedis