Didazoon

"Dida" abbreviates (in Chinese) the China University of Geosciences.{{harvnb|Shu|Conway Morris|Han|Chen|2001|page=419}} {{small|(Note: it is unclear from the source whether the China University of Geosciences (Wuhan) or China University of Geosciences (Beijing) is being referenced)}}

The fossils show that the body of the animal was covered in a thin, flexible cuticle. The anterior part of the body was divided into six segments, with fairly broad membranes separating the segments, and the posterior part of the body was divided into seven segments. The constriction between the anterior and posterior parts of the animal shows creasing, and the authors hypothesize that it was quite flexible. The fossils are interpreted as showing a large anterior opening, presumably a mouth, a spacious anterior cavity, an alimentary canal, possibly voluminous in the anterior section, and a narrow intestine in the posterior section, straight or coiled (in one specimen). There are five structures on each side of the anterior portion that the authors interpret as gills. Narrow strands towards the lateral margins, sometimes branched, may represent vascular tissue. The authors also identify a dark strand on the lower interior surface of the anterior section, which they speculate is an endostyle.

Didazoon is the type genus of the Didazoonidae, which one 2024 study has found to be a paraphyletic grade of the vetulicolians closest to crownward chordates as shown in this simplified cladogram,{{harvnb|Mussini|Smith|Vinther|Rahman|2024|pages=6–7}} which labels Vetulicolidae based on a 2018 phylogeny{{harvnb|Li|Williams|Gabbott|Chen|2018|pages=1083–1084}} and Didazoonidae based on the Paleobiology Database:{{cite web|title=†family Didazoonidae Shu and Han 2001 |website=Paleobiology Database |url=https://paleobiodb.org/classic/basicTaxonInfo?taxon_no=txn:378668 |accessdate=December 8, 2024}}

{{Clade|style=font-size:85%;line-height:85%

|label1=Chordata

|sublabel1={{small|(total group)}}

|1={{Clade

|1=Banffia†

|2=Heteromorphus†

|3={{Clade

|1=Skeemella†

|2={{Clade

|1=Nesonektris†

|2={{Clade

|1=Vetulicolidae†

|2={{Clade

|grouplabel1={{clade labels |bar1=indigo |label1="Didazoonidae"}}

|1=Didazoon† |barbegin1=indigo

|2=Pomatrum† |bar2=indigo

|3=Yuyuanozoon† |barend3=indigo

|4={{Clade

|1=Yunnanozoon†

|2={{Clade

|1=Cathaymyrus†

|2=Pikaia†

|3=Chordata
{{small|(crown group)}}

}} }} }} }} }} }} }} }}

An earlier study in 2014 place vetulicolians as the sister-group to tunicates, but was unable to resolve any relationships among vetulicolians as a group:{{harvnb|García-Bellido|Lee|Edgecombe|Jago|2014|page=9}}

{{Clade|style=font-size:85%;line-height:85%

|label1=Vetulicolia†

|1={{Clade

|grouplabel4={{clade labels |bar1=indigo |label1="Didazoonidae"}}

|1=Vetulicola†

|2=Beidazoon†

|3=Ooedigera†

|4=Pomatrum† / Xidazoon† |barbegin4=indigo

|5=Didazoon† |bar5=indigo

|6=Yuyuanozoon† |barend6=indigo

|7=Banffia†

|8=Heteromorphus†

|9=Nesonektris†

}}

|2=Tunicata

}}

{{Portal|Palaeontology}}

• Maotianshan shales

{{Reflist}}

{{refbegin}}

• {{cite journal|last1=García-Bellido |first1=Diego C. |last2=Lee |first2=Michael S. Y. |last3=Edgecombe |first3=Gregory D. |last4=Jago |first4=James B. |last5=Gehling |first5=James G. |last6=Paterson |first6=John R. |year=2014 |title=A new vetulicolian from Australia and its bearing on the chordate affinities of an enigmatic Cambrian group |journal=BMC Evolutionary Biology |volume=14 |page=214 |doi=10.1186/s12862-014-0214-z |pmc=4203957 |pmid=25273382 |doi-access=free }}
• {{cite journal|last1=Li |first1=Yujing |last2=Williams |first2=Mark |last3=Gabbott |first3=Sarah E. |last4=Chen |first4=Ailen |last5=Cong |first5=Peiyun |last6=Hou |first6=Xianguang |title=The enigmatic metazoan Yuyuanozoon magnificissimi from the early Cambrian Chengjiang Biota, Yunnan Province, South China |journal=Journal of Paleontology |volume=92 |number=6 |year=2018 |pages=1081–1091 |doi=10.1017/jpa.2018.18|hdl=2381/41417 |hdl-access=free }}
• {{cite journal |last1=Mussini |first1=G. |last2=Smith |first2=M. P. |last3=Vinther |first3=J. |last4=Rahman |first4=I. A. |last5=Murdock |first5=D. J. E. |last6=Harper |first6=D. A. T. |last7=Dunn |first7=F. S. |title=A new interpretation of Pikaia reveals the origins of the chordate body plan |journal=Current Biology |date=2024 |volume=34 |issue=13 |pages=2980–2989.e2 |doi=10.1016/j.cub.2024.05.026 |doi-access=free |pmid=38866005 |hdl=10141/623098 |hdl-access=free }}
• {{cite journal |last1=Shu |first1=D. G. |last2=Conway Morris |first2=S. |last3=Han |first3=J. |last4=Chen |first4=L. |last5=Zhang |first5=X. L. |last6=Zhang |first6=Z. F. |last7=Liu |first7=H. Q. |last8=Li |first8=Y. |last9=Liu |first9=J. N. |date=November 22, 2001 |title=Primitive deuterostomes from the Chengjiang Lagerstätte (Lower Cambrian, China) |journal=Nature |volume=414 |issue=6862 |pages=419–424 |bibcode=2001Natur.414..419S |doi=10.1038/35106514 |issn=0028-0836 |pmid=11719797 |s2cid=4345484}}

{{refend}}

{{Vetulicolia}}

{{Taxonbar|from=Q3707018}}

Category:Animals described in 2001

Category:Maotianshan shales fossils

Category:Monotypic vertebrate genera

Category:Prehistoric vertebrate genera

Category:Vetulicolia