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by | Mar 16, 2018 | Hosta

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Artist's reconstruction of Plourdosteus trautscholdi

Plourdosteus is an extinct genus of placoderm arthrodire which was relatively widespread in Euramerica during the Givetian to Frasnian ages of the Devonian.[1] It was a small placoderm, with P. canadensis specimen MNHM 2-177 measuring 37.5 cm (14.8 in) long.[2]

Etymology

The name Plourdosteus commemorates the Plourde family at Miguasha National Park.[3]

Taxonomy

Plourdosteus was previously assigned to the family Plourdosteidae within the Coccosteomorphi. However, subsequent studies found the family Plourdosteidae to be polyphyletic and should be dismissed. Plourdosteus was then proposed to be a member of Panxiosteidae.[4][5] In the 2010 Carr & Hlavin phylogenetic study, Panxiosteidae was recognized as the sister taxon to the family Dunkleosteidae, which together comprised the superfamily Dunkleosteoidea (one of the three major clades of Eubrachythoraci).[4]

The phylogeny of Plourdosteus within Panxiosteidae is shown in the cladogram below from the 2013 Zhu & Zhu study:[5]

Eubrachythoraci
Dunkleosteoidea
Pachyosteomorphi

However, the subsequent 2016 Zhu et al. study using a larger morphological dataset recovered Panxiosteidae well outside of Dunkleosteoidea, instead within Coccosteomorphi and then Coccosteoidea as the sister group of Coccosteidae, as shown in the cladogram below:[6]

Eubrachythoraci
Coccosteomorphi
Pachyosteomorphi

References

  1. ^ S. V. Moloshnikov (2008). "The placoderm Plourdosteus livonicus (Eastman) in the early Frasnian of the Central Devonian Field and the trophic structure of the Mikhailovskii Fish Assemblage". Paleontological Journal. 42 (6): 607–614. doi:10.1134/S0031030108060063.
  2. ^ Engelman, Russell K. (2023). "A Devonian Fish Tale: A New Method of Body Length Estimation Suggests Much Smaller Sizes for Dunkleosteus terrelli (Placodermi: Arthrodira)". Diversity. 15 (3). 318. doi:10.3390/d15030318.
  3. ^ "Plourdosteus". Miguasha National Park. 2007. Retrieved June 21, 2010.
  4. ^ a b Carr, R.K.; Hlavin, W.J. (2010). "Two new species of Dunkleosteus Lehman, 1956, from the Ohio Shale Formation (USA, Famennian) and the Kettle Point Formation (Canada, Upper Devonian), and a cladistic analysis of the Eubrachythoraci (Placodermi, Arthrodira)". Zoological Journal of the Linnean Society. 159 (1): 195–222. doi:10.1111/j.1096-3642.2009.00578.x.
  5. ^ a b You-An Zhu; Min Zhu (2013). "A redescription of Kiangyousteus yohii (Arthrodira: Eubrachythoraci) from the Middle Devonian of China, with remarks on the systematics of the Eubrachythoraci". Zoological Journal of the Linnean Society. 169 (4): 798–819. doi:10.1111/zoj12089.
  6. ^ Zhu, You-An; Zhu, Min; Wang, Jun-Qing (1 April 2016). "Redescription of Yinostius major (Arthrodira: Heterostiidae) from the Lower Devonian of China, and the interrelationships of Brachythoraci". Zoological Journal of the Linnean Society. 176 (4): 806–834. doi:10.1111/zoj.12356. ISSN 0024-4082.


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