Acosmia

{{Short description|Genus of ecdysozoans}}

{{Speciesbox

| parent_authority = Chen & Zhoi 1997

| fossil_range = Chengjiang

| image = RCCBYU 10235 Acosmia maotiania.png

| image_caption = Fossil specimen

| display_parents = 2

| taxon = Acosmia maotiania

| authority = Chen & Zhoi 1997

}}

Acosmia is an extinct genus of marine worm from the Cambrian aged Chengjiang biota of Yunnan, China. It is represented by a single rare species, Acosmia maotiania, that reached 45 mm in length and 9 mm in width.{{Cite book|url=https://books.google.com/books?id=LZD-MQtfMt0C&dq=Acosmia+maotiania&pg=PA68|title=The Cambrian Fossils of Chengjiang, China: The Flowering of Early Animal Life|isbn=9780470999943|last1=Hou|first1=Xian-Guag|last2=Aldridge|first2=Richard|last3=Bergstrom|first3=Jan|last4=Siveter|first4=David J|last5=Siveter|first5=Derek|last6=Feng|first6=Xiang-Hong|date=2008-04-15|publisher=John Wiley & Sons }} It was likely a burrowing animal that fed by deposit feeding. While originally suggested to be a priapulid (penis worm), a 2020 study proposed to be a stem-group ecdysozoan, due to lacking the radial pharygneal armature that characterises modern ecdysozoans, including priapulids.{{Cite journal |last1=Howard |first1=Richard J. |last2=Edgecombe |first2=Gregory D. |last3=Shi |first3=Xiaomei |last4=Hou |first4=Xianguang |last5=Ma |first5=Xiaoya |date=2020-11-23 |title=Ancestral morphology of Ecdysozoa constrained by an early Cambrian stem group ecdysozoan |journal=BMC Evolutionary Biology |language=en |volume=20 |issue=1 |pages=156 |doi=10.1186/s12862-020-01720-6 |issn=1471-2148 |pmc=7684930 |pmid=33228518 |bibcode=2020BMCEE..20..156H |doi-access=free }}