Biology:Didazoonidae
Didazoonidae is a vetulicolian family within the order Vetulicolata. It is characterized by a relatively thin-walled, non-biomineralized body and a large, round anterior opening surrounded by an oral disc.[1][2] It may be paraphyletic,[3] even if the phylum Vetulicolia is monophyletic.[4]
Description
Didazoonids have an ovoid to subquadrate anterior section divided into six subdivisions marked by five circumventing lines perpendicular to the body axis. Cowl-shaped lateral pouches appear along each side of the anterior section, coincident with the five dividing lines. The anterior opening is large, round, and surrounded by a circumventing oral disc. The posterior section has seven segments, which in some species each carry up to six annulations.[2]
Taxonomy
Didazoonidae was erected to group Didazoon. Xidazoon. and Pomatrum, although Xidazoon has since been shown to be a junior synonym of Pomatrum.[1] Yuyuanozoon was moved to the Didazoonidae after additional specimens illuminated more details of the anterior opening and posterior segment annulations.[5]
Nesonektris has also been assigned to Didazoonidae by some workers,[6] but this has not been widely accepted.[7][8]
A 2024 study has found the Didazoonidae (without Nesonektris) to be a paraphyletic grade of the vetulicolians closest to crownward chordates as shown in this simplified cladogram:[3]
| Chordata |
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(total group)
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An earlier study in 2014 placed vetulicolians as the sister-group to tunicates, but was unable to resolve any relationships among vetulicolians as a group:[4]
| Vetulicolia† |
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Tunicata | |||||||||||||||||||||||||||||
References
- ↑ 1.0 1.1 Aldridge et al. 2007, pp. 145–146
- ↑ 2.0 2.1 Li et al. 2018, p. 1085 (Note: This paper uses different terminology for vetulicolian anatomy explained on page 1082; this page uses the more common terms regardless of source)
- ↑ 3.0 3.1 Mussini et al. 2024, pp. 6–7 (Note: The cladogram is simplified using the definition of Vetulicolidae from Li et al. 2018, cited elsewhere on this page)
- ↑ 4.0 4.1 García-Bellido et al. 2014, p. 9
- ↑ Li et al. 2018, p. 1082
- ↑ Li et al. 2018, p. 1084
- ↑ "†Nesonektris García-Bellido et al. 2014". https://paleobiodb.org/classic/basicTaxonInfo?taxon_no=txn:358335. Retrieved December 8, 2024.
- ↑ "†family Didazoonidae Shu and Han 2001". https://paleobiodb.org/classic/basicTaxonInfo?taxon_no=txn:378668. Retrieved December 8, 2024.
Works cited
- Aldridge, Richard J.; Hou, Xian-guang; Siveter, David J.; Siveter, Derek J.; Sarah E., Gabbott (2007). "The systematics and phylogenetic relationships of vetulicolians". Palaeontology 50: 131–168. doi:10.1111/j.1475-4983.2006.00606.x.
- Chen, Ailin; Feng, Hongzhen; Zhu, Maoyan; Ma, Dongsheng; Li, Ming (2003). "A New Vetulicolian from the Early Cambrian Chengjiang Fauna in Yunnan of China". Acta Geologica Sinica 77 (3): 281–287. doi:10.1111/j.1755-6724.2003.tb00742.x.
- García-Bellido, Diego C.; Lee, Michael S. Y.; Edgecombe, Gregory D.; Jago, James B.; Gehling, James G.; Paterson, John R. (2014). "A new vetulicolian from Australia and its bearing on the chordate affinities of an enigmatic Cambrian group". BMC Evolutionary Biology 14: 214. doi:10.1186/s12862-014-0214-z. PMID 25273382.
- Li, Yujing; Williams, Mark; Gabbott, Sarah E.; Chen, Ailen; Cong, Peiyun; Hou, Xianguang (2018). "The enigmatic metazoan Yuyuanozoon magnificissimi from the early Cambrian Chengjiang Biota, Yunnan Province, South China". Journal of Paleontology 92 (6): 1081–1091. doi:10.1017/jpa.2018.18.
- Mussini, G.; Smith, M. P.; Vinther, J.; Rahman, I. A.; Murdock, D. J. E.; Harper, D. A. T.; Dunn, F. S. (2024). "A new interpretation of Pikaia reveals the origins of the chordate body plan". Current Biology 34 (13): 2980–2989.e2. doi:10.1016/j.cub.2024.05.026. PMID 38866005.
- Shu, D. G.; Conway Morris, S.; Han, J.; Chen, L.; Zhang, X. L.; Zhang, Z. F.; Liu, H. Q.; Li, Y. et al. (November 22, 2001). "Primitive deuterostomes from the Chengjiang Lagerstätte (Lower Cambrian, China)". Nature 414 (6862): 419–424. doi:10.1038/35106514. ISSN 0028-0836. PMID 11719797. Bibcode: 2001Natur.414..419S.
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