Vetulicolida is a class of vetulicolians. It consists of the order Vetulicolata (which contains the familes Vetulicolidae and Didazoonidae)[1] and the genus Nesonektris, which is of uncertain placement.[2] It is distinguished from the Banffozoa by the number and size of posterior segments as well as features of the anterior section.[3]
| Vetulicolida Temporal range:
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| Fossils and diagrams of Nesonektris | |
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| Artist's reconstruction of Yuyuanozoon (a didazoonid, foreground) and Vetulicola rectangulata (a vetulicolid) | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade?: | †Vetulicolia |
| Class: | †Vetulicolida Chen and Zhou, 1997 |
| Orders | |
Description
editThe Vetulicolidans anterior body appears to consist of fused segments, with five gill pouches at the intersections of the segment boundaries and a lateral groove that does not reach the posterior edge. The posterior section is clearly segmented with relatively wide segments comparred to banffozoans such as Banffia or Heteromorphus.[3]
Taxonomy
editIn 1997, Chen and Zhou defined Vetulicolida as a class to contain Vetulicola and Banffia. Hou and Bergström also defined Vetulicolida that same year, but as an order containing the new family Vetulicolidae. The name Vetulicolida was used at either or both ranks until 2007, when a comprehensive phylogeny renamed the order to Vetulicolata.[1] By this point Banffia had been moved to its own class, Banffozoa.
Nesonektris has been proposed to be a didazoonid,[4] but this has not been broadly accepted,[5] even by sources that accept the paper's other reassignment (of Yuyuanozoon to Didazoonidae).[6]
A 2024 analysis found Vetulicolida to be the more recent portion of a paraphyletic grade leading to more crownward chordates, with Nesonektris basal to Vetulicolata (Vetulicolidae is labeled according to a 2018 phylogeny):[7][4]
"Vetulicolida"
"Vetulicolata" (part of "Vetulicolida") |
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:[2]
References
edit- ^ a b Aldridge et al. 2007, p. 133
- ^ a b García-Bellido et al. 2014, p. 2
- ^ a b Aldridge et al. 2007, p. 133, 150–151
- ^ a b Li et al. 2018, pp. 1038–1085
- ^ "†Nesonektris García-Bellido et al. 2014". Paleobiology Database. Retrieved December 8, 2024.
- ^ "†family Didazoonidae Shu and Han 2001". Paleobiology Database. Retrieved December 8, 2024.
- ^ Mussini et al. 2024, pp. 6–7
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.
- 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.