Xianguangia is a soft-bodied sea anemone-like fossil animal from the Chengjiang Biota of China.[2]
| Xianguangia Temporal range: Cambrian Stage 3,
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| Fossil of Xianguangia sinica | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Ctenophora |
| Genus: | †Xianguangia |
| Species: | †X. sinica
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| Binomial name | |
| †Xianguangia sinica Chen & Erdtmann, 1991
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Description
editXianguangia sinica has a cylindrical body with a whorl of nearly 16 tentacles around the oral disc, similar to the modern anthozoans. The tentacles are feather-like with dense pinnules on both sides of the axis which would have been well adapted to filter feeding. A bowl-shaped attachment disc at the basal part might commonly have been buried in the sediment to allow its sedentary strategy on the sea floor. The body above the pedal disc is broad and cylindrical and may correspond to the internal gastrovascular cavity. It displays several distinct longitudinal grooves and ridges on the surface, indicating possible mesenteries.[3] However, its phylogenetic affinity has long been questioned;[3] it has even been alleged to be related to members of the Ediacara biota.[4] Studies from the late 2010s onwards argued that it was likely to be member of the stem-group of Ctenophora (comb jellies), related to taxa like Dinomischus and Siphusauctum.[5][6]
The fossils, found in Yunnan province, China, were initially described as three distinct species, Xianguangia sinica, Chengjiangopenna wangii, and Galeaplumosus abilus, and then assembled into one proposed species, X. sinica, in 2017.[7] The animal was polyp-like, its gastric cavity divided by septa; it had a second body cavity in its holdfast, and densely-plumed feather-like tentacles, implying that it was a suspension feeder. Early cnidarians were probably also benthic suspension feeders, unlike later mainly predatory cnidarians.[7]
References
edit- ^ Yang, C.; Li, X.-H.; Zhu, M.; Condon, D. J.; Chen, J. (2018). "Geochronological constraint on the Cambrian Chengjiang biota, South China" (PDF). Journal of the Geological Society. 175 (4): 659–666. doi:10.1144/jgs2017-103. ISSN 0016-7649.
- ^ Erwin, D. H.; Laflamme, M.; Tweedt, S. M.; Sperling, E. A.; Pisani, D.; Peterson, K. J. (2011). "The Cambrian Conundrum: Early Divergence and Later Ecological Success in the Early History of Animals". Science. 334 (6059): 1091–1097. Bibcode:2011Sci...334.1091E. doi:10.1126/science.1206375. PMID 22116879. S2CID 7737847.
- ^ a b Qian-Ping Leia; et al. (2013). "Sedentary habits of anthozoa-like animals in the Chengjiang Lagerstätte: Adaptive strategies for Phanerozoic-style soft substrates". Gondwana Research. 25 (3): 966–974. doi:10.1016/j.gr.2013.01.007.
- ^ Han, J.; Kubota, S.; Uchida, H. O.; Stanley Jr, G. D.; Yao, X.; Shu, D.; Li, Y.; Yasui, K. (2010). Lalueza-Fox, Carles (ed.). "Tiny Sea Anemone from the Lower Cambrian of China". PLoS One. 5 (10): e13276. Bibcode:2010PLoSO...513276H. doi:10.1371/journal.pone.0013276. PMC 2954142. PMID 20967244.
- ^ Zhao, Yang; Vinther, Jakob; Parry, Luke A.; Wei, Fan; Green, Emily; Pisani, Davide; Hou, Xianguang; Edgecombe, Gregory D.; Cong, Peiyun (April 2019). "Cambrian Sessile, Suspension Feeding Stem-Group Ctenophores and Evolution of the Comb Jelly Body Plan". Current Biology. 29 (7): 1112–1125.e2. doi:10.1016/j.cub.2019.02.036.
- ^ Zhao, Yang; Hou, Xian-guang; Cong, Pei-yun (2023-01-01). "Tentacular nature of the 'column' of the Cambrian diploblastic Xianguangia sinica". Journal of Systematic Palaeontology. 21 (1). doi:10.1080/14772019.2023.2215787. ISSN 1477-2019.
- ^ a b Ou, Qiang; Han, Jian; Zhang, Zhifei; Shu, Degan; Sun, Ge; Mayer, Georg (2017-07-31). "Three Cambrian fossils assembled into an extinct body plan of cnidarian affinity". Proceedings of the National Academy of Sciences. 114 (33): 8835–8840. doi:10.1073/pnas.1701650114. PMC 5565419. PMID 28760981.
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