Qianodus

Qianodus
Temporal range: Aeronian
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Tooth whorl of Qianodus duplicis. Volume rendering of the holotype specimen shown in lateral view with colour coded primary (yellow and blue) and accessory (red) teeth.
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Genus: Qianodus
Andreev et al. 2022
Species:
Q. duplicis
Binomial name
Qianodus duplicis
Andreev et al. 2022

Qianodus (from the Chinese: 黔, 'Qian', the ancient name for Guizhou and the Greek: ὀδούς, odus, 'tooth') is a jawed vertebrate genus that is based on disarticulated teeth from the lower Silurian (Aeronian, c. 439 Myr) of China.[1] The type and only species of Qianodus, Q. duplicis[1], is known from compound dental elements called tooth whorls,[2][3][4] each consisting of multiple tooth generations carried by a spiral-shaped base. The tooth whorls of Qianodus represent the oldest unequivocal remains of a toothed vertebrate, predating previously recorded occurrences[5] by about 14 million years. The specimens attributed to the genus come from limestone conglomerate beds of the Rongxi Formation exposed near the village of Leijiatun, Guizhou Province, China. These horizons have been interpreted as tidal deposits1 that form part of the shallow marine sequences of the Rongxi Formation.[6]

  1. ^ a b Andreev, Plamen S.; Sansom, Ivan J.; Li, Qiang; Zhao, Wenjin; Wang, Jianhua; Wang, Chun-Chieh; Peng, Lijian; Jia, Liantao; Qiao, Tuo; Zhu, Min (2022-09-28). "The oldest gnathostome teeth". Nature. 609 (7929): 964–968. Bibcode:2022Natur.609..964A. doi:10.1038/s41586-022-05166-2. ISSN 0028-0836. PMID 36171375. S2CID 252569771.
  2. ^ Maisey, John G.; Turner, Susan; Naylor, Gavin J.P.; Miller, Randall F. (December 2013). "Dental patterning in the earliest sharks: Implications for tooth evolution". Journal of Morphology. 275 (5): 586–596. doi:10.1002/jmor.20242. ISSN 0362-2525. PMID 24347366. S2CID 22115814.
  3. ^ Qu, Qingming; Sanchez, Sophie; Blom, Henning; Tafforeau, Paul; Ahlberg, Per Erik (2013-08-12). "Scales and Tooth Whorls of Ancient Fishes Challenge Distinction between External and Oral 'Teeth'". PLOS ONE. 8 (8): e71890. Bibcode:2013PLoSO...871890Q. doi:10.1371/journal.pone.0071890. ISSN 1932-6203. PMC 3741376. PMID 23951264.
  4. ^ Rücklin, Martin; King, Benedict; Cunningham, John A.; Johanson, Zerina; Marone, Federica; Donoghue, Philip C. J. (2021-05-06). "Acanthodian dental development and the origin of gnathostome dentitions". Nature Ecology & Evolution. 5 (7): 919–926. doi:10.1038/s41559-021-01458-4. hdl:1983/27f9a13a-1441-410e-b9a7-116b42cd40f7. ISSN 2397-334X. PMID 33958756. S2CID 233985000.
  5. ^ Brazeau, Martin D.; Friedman, Matt (2015-04-22). "The origin and early phylogenetic history of jawed vertebrates". Nature. 520 (7548): 490–497. Bibcode:2015Natur.520..490B. doi:10.1038/nature14438. ISSN 0028-0836. PMC 4648279. PMID 25903631.
  6. ^ Rong, JiaYu; Wang, Yi; Zhang, XiaoLe (2012-03-22). "Tracking shallow marine red beds through geological time as exemplified by the lower Telychian (Silurian) in the Upper Yangtze Region, South China". Science China Earth Sciences. 55 (5): 699–713. Bibcode:2012ScChD..55..699R. doi:10.1007/s11430-012-4376-5. ISSN 1674-7313. S2CID 195310068.