Editing Nectocaris (section)

===''Petalilium''===
[[File:Petalilium HK-MF-00001A 098.g2.jpg|thumb|300x300px|Fossil of ''Petalilium'']]
'''''Petalilium''''' (sometimes misspelled '''''Petalium''''')<ref name="Chen2005">{{cite journal |last1=Chen |first1=J.Y. |last2=Huang |first2=D.Y. |last3=Bottjer |first3=D.J. |year=2005 |title=An Early Cambrian problematic fossil: ''Vetustovermis'' and its possible affinities |journal=Proceedings of the Royal Society B |volume=272 |issue=1576 |pages=2003–2007 |pmid=16191609 |doi=10.1098/rspb.2005.3159 |pmc=1559895}}</ref> is an enigmatic genus of [[Cambrian]] organism known from the Haikou area,<ref name=Steiner2005>{{cite journal |last1=Steiner |first1=M. |last2=Zhu |first2=M. |last3=Zhao |first3=Y. |last4=Erdtmann |first4=B. |year=2005 |title=Lower Cambrian Burgess Shale-type fossil associations of South China |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |volume=220 |issue=1–2 |pages=129–152 |bibcode=2005PPP...220..129S |doi=10.1016/j.palaeo.2003.06.001}}</ref> from the Maotianshan mudstone member of the [[Chengjiang biota]].<ref name='Han2006'>{{cite journal |last1=Han |first1=J. |last2=Shu |first2=D. |last3=Zhang |first3=Z. |last4=Liu |first4=J. |last5=Zhang |first5=X. |last6=Yao |first6=Y. |year=2006 |title=Preliminary notes on soft-bodied fossil concentrations from the Early Cambrian Chengjiang deposits |journal=Chinese Science Bulletin |volume=51 |issue=20 |page=2482 |doi=10.1007/s11434-005-2151-0 |bibcode=2006ChSBu..51.2482H|s2cid=129162009 }}</ref> The taxon is a junior synonym of ''Nectocaris pteryx''.<ref name="Smith2013c"/>

Fossils of ''Petalilium''{{efn|''Petalilium'' was originally described as ''Vetustovermis'' by Chen ''et al''. (2005),<ref name="Chen2005"/> but recognised as ''Petalilium'' by Smith & Caron (2010).<ref name="SmithAndCaron2010"/>}} show a [[Anatomical terms of location#Directional terms|dorsoventrally]] flattened body, usually 5 to 6&nbsp;centimetres, but ranging from 1.5 to 10&nbsp;cm. It has an ovate trunk region and a large [[muscle|muscular]] foot, and a head with stalked eyes and a pair of long tentacles. The trunk region possesses about 50&nbsp;soft, flexible, [[Anatomical terms of location#Invertebrate directional terms|transverse]] bars, lateral serialised structures of unknown function. The upper part of the body, interpreted as a [[Mantle (mollusc)|mantle]], is covered with a random array of spines on the back, while gills project underneath. A complete, tubular gut runs the length of the body.

Whilst it was originally described as a [[Phyllocarida|phyllocarid]],<ref name=Luo1999/> and a [[ctenophore]] affinity has been suggested,<ref>{{cite book |author1=Chen, L.Z. |author2=Luo, H.L. |author3=Hu, S.X. |author4=Yin, J.Y. |author5=Jiang, Z.W. |author6=Wu, Z.L. |author7=Li, F. |author8=Chen, A.L. |year=2002 |title=Early Cambrian Chengjiang Fauna in Eastern Yunnan, China |publisher=Yunnan Science and Technology Press |place=Kunming |pages=199 |language=Chinese, English}}</ref> neither interpretation is supported by any compelling evidence.<ref name='Hu2007'>{{cite journal |last1=Hu |first1=S. |last2=Steiner |first2= M. |last3=Zhu |first3=M. |last4=Erdtmann |first4=B.D. |last5=Luo |first5=H. |last6=Chen |first6=L. |last7=Weber |first7=B. |year=2007 |title=Diverse pelagic predators from the Chengjiang Lagerstätte and the establishment of modern-style pelagic ecosystems in the early Cambrian |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |volume=254 |issue=1–2 |pages=307–316 |doi=10.1016/j.palaeo.2007.03.044 |bibcode=2007PPP...254..307H}}</ref>

Some of the characters observed in Chen ''et al''.'s (2005) study<ref name="Chen2005"/> suggested that ''Petalilium'' may be related to ''Nectocaris''.<ref name="SmithAndCaron2010"/>