| one publication added to basket [229180] | A Silurian placoderm with osteichthyan-like marginal jaw bones
Zhu, M.; Yu, X.; Ahlberg, P.E.; Choo, B.; Lu, J.; Qiao, T.; Qu, Q.; Zhao, W.; Jia, L.; Blom, H.; Zhu, Y. (2013). A Silurian placoderm with osteichthyan-like marginal jaw bones. Nature (Lond.) 501(7470): 188-193. http://dx.doi.org/10.1038/nature12617
In: Nature: International Weekly Journal of Science. Nature Publishing Group: London. ISSN 0028-0836; e-ISSN 1476-4687, more
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| Keywords |
Aquatic organisms > Marine organisms > Fish > Marine fish
Fossils
Marine/Coastal |
| Authors | | Top |
- Zhu, M.
- Yu, X.
- Ahlberg, P.E.
- Choo, B.
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- Lu, J.
- Qiao, T.
- Qu, Q.
- Zhao, W.
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| Abstract |
The gnathostome (jawed vertebrate) crown group comprises two extant clades with contrasting character complements. Notably, Chondrichthyes (cartilaginous fish) lack the large dermal bones that characterize Osteichthyes (bony fish and tetrapods). The polarities of these differences, and the morphology of the last common ancestor of crown gnathostomes, are the subject of continuing debate. Here we describe a three-dimensionally preserved 419-million-year-old placoderm fish from the Silurian of China that represents the first stem gnathostome with dermal marginal jaw bones (premaxilla, maxilla and dentary), features previously restricted to Osteichthyes. A phylogenetic analysis places the new form near the top of the gnathostome stem group but does not fully resolve its relationships to other placoderms. The analysis also assigns all acanthodians to the chondrichthyan stem group. These results suggest that the last common ancestor of Chondrichthyes and Osteichthyes had a macromeric dermal skeleton, and provide a new framework for studying crown gnathostome divergence. |
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