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]
| Didazoonidae Temporal range:
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|---|---|
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade?: | †Vetulicolia |
| Class: | †Vetulicolida |
| Order: | †Vetulicolata |
| Family: | †Didazoonidae Shu and Han in Shu et al. 2001 |
| Type genus | |
| †Didazoon Shu and Han in Shu et al. 2001
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| Genera | |
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Description
editDidazoonids 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
editDidazoonidae 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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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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References
edit- ^ a b Aldridge et al. 2007, pp. 145–146
- ^ a b 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)
- ^ a b 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)
- ^ a b 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". Paleobiology Database. Retrieved December 8, 2024.
- ^ "†family Didazoonidae Shu and Han 2001". Paleobiology Database. Retrieved December 8, 2024.
Works cited
edit- 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. S2CID 85722738.
- 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. S2CID 128895860.
- 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. PMC 4203957. 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.; Liu, J. N. (November 22, 2001). "Primitive deuterostomes from the Chengjiang Lagerstätte (Lower Cambrian, China)". Nature. 414 (6862): 419–424. Bibcode:2001Natur.414..419S. doi:10.1038/35106514. ISSN 0028-0836. PMID 11719797. S2CID 4345484.