Placodermi

Placodermi (a Graecis πλάξ 'lamina' + δέρμα 'cutis') est classis piscium praehistoricorum armatorum, solum ex fossilibus nobis notorum, qui ab aevo Siluriano ad finem aevi Devoniani vigebant. Eorum caput et thorax durissimis laminis articulatis tegebantur, et reliquium corporis squamosum vel nudum fuit, secundum speciem. Inter prima gnathostomata fuerunt; eorum maxillae ut videtur ex eorum primis arcibus branchiarum creverunt. Classis Placodermorum paraphyletica plerumque putatur, quia in nonnullis gregibus exterioribus vel distinctis omnium vertebratorum maxillis praeditorum viventiumque taxis sororalibus consistit, quae ex eis orta sunt. Quod ab Entelognatho monstratur, fossile abhinc annorum 419 milliones ex Sina orto, solo placodermo noto cui fuit maxilla ossea maxillarum in piscibus osseis hodiernis inventarum similis, mandibulo quod in homine sapiente aliisque tetrapodis invenitur non excluso.^[1][2] Mandibula aliorum placodermorum simpliciora fuerunt, inque uno ore constiterunt.^[3] Placodermi fuerunt primi pisces qui pinnas pelvicas evolverunt, praecursores membrorum posteriorum in tetrapodis, cum dentibus veris.^[4] Greges paraphyletici ancipites sunt, quia coniunctiones phylogeneticae, proprietates, et exstinctio incertae sunt.^[5][6] Fossilia Incisoscuti, Materpiscis, et Austroptyctodi, trium generum aliorum ex aevo abhinc annorum 380 milliones ortorum, sunt prima partus vivi exempla nota.^[7]

Bothriolepis panderi (fossile) pinnas pectorales monstrat.

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Animalia — Chordata

Subphylum : Vertebrata 
Infraphylum : Gnathostomata 
Classis : †Placodermi 
McCoy, 1848

   

Palaeontologia

430–358.9 m.a.: 

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Late Llandovery – Late Devonian

Subdivisiones: Ordines

Antiarchi †

Arthrodira †
Brindabellaspida †
Petalichthyida †
Phyllolepida †
Ptyctodontida †
Rhenanida †
Acanthothoraci †
?Pseudopetalichthyida †

?Stensioellida †

Cladogramma

Cladogramma insequens coniunctiones inter placodermos monstrat.^[8]

Homostius et Pterichthys.

Diandongpetalichthys.

	Stensioella Placodermi Pseudopetalichthys Brindabellaspis Acanthothoraci Rhenanida Yunnanolepis Euantiarcha Petalichthyida Ptyctodontida Arthrodira Wuttagoonaspis Actinolepidae Phyllolepida Phlyctaeniida Brachythoraci Holonema Antineosteus Buchanosteidae Eubrachythoraci Pholidosteus Tapinosteus Coccosteus Torosteus Plourdosteus Dunkleosteus Brachyosteus Erromenosteus Gorgonichthys Titanichthys

Bibliographia

• Ahlberg, P. E., K. Trinajstic, Z. Johanson, et J. A. Long. 2009. "Pelvic claspers confirm chondrichthyan-like internal fertilization in arthrodires." Nature 460 (7257): 888–89. Bibcode:2009Natur.460..888A. doi:10.1038/nature08176. PMID 19597477.
• Janvier, P. 1998. Early Vertebrates. Oxoniae et Novi Eboraci: Oxford University Press. ISBN 0-19-854047-7.
• Long, J. A. 1983. "New bothriolepid fishes from the Late Devonian of Victoria, Australia." Palaeontology 26: 295–320.
• Long, J. A. 1984. "New phyllolepids from Victoria and the relationships of the group." Proceedings of the Linnean Society of New South Wales 107: 263–308.
• Long, J. A. 1996. The Rise of Fishes: 500 Million Years of Evolution. Baltimorae: The Johns Hopkins University Press. ISBN 0-8018-5438-5.
• Long, J. A., et K. Trinajstic. 2010. "The Late Devonian Gogo Formation Lagerstatte – Exceptional preservation and Diversity in early Vertebrates." Annual Review of Earth and Planetary Sciences 38: 255–79. Bibcode:2010AREPS..38..255L. doi:10.1146/annurev-earth-040809-152416.
• Long, J. A., K. Trinajstic, G. C. Young, et T. Senden. 2008. "Live birth in the Devonian." Nature 453 (7195): 650–52. Bibcode:2008Natur.453..650L. doi:10.1038/nature06966. PMID 18509443.
• Long, J. A., K. Trinajstic, et Z. Johanson. 2009. "Devonian arthrodire embryos and the origin of internal fertilization in vertebrates." Nature 457 (7233): 1124–27. Bibcode:2009Natur.457.1124L. doi:10.1038/nature07732. PMID 19242474.
• Zhu, M, X. Yu, B. Choo, J. Wang, et L. Jia. 2012. "An antiarch placoderm shows that pelvic girdles arose at the root of jawed vertebrates." Biology Letters 8 (3): 453–56. doi:10.1098/rsbl.2011.1033. PMC 3367742. PMID 22219394.

Notae

1. Barford, Eliot (25 Septembris 2013). "Ancient fish face shows roots of modern jaw". Nature .
2. Meredith Smith, Moya; Clark, Brett; Goujet, Daniel; Johanson, Zerina (17 Augusti 2017). "Evolutionary origins of teeth in jawed vertebrates: conflicting data from ac+anthothoracid dental plates ('Placodermi')". Palaeontology 60 (6): 829–836 .
3. "Entelognathus: The Fish with the First Modern Face" .
4. Rücklin, M.; Donoghue, P. C. J.; Johanson, Z.; Trinajstic, K.; Marone, F.; Stampanoni, M. (2012). "Development of teeth and jaws in the earliest jawed vertebrates". Nature 491 (7426): 748–751 .
5. Schilhab, Theresa; Stjernfelt, Frederik; Deacon, Terrence (26 Martii 2012). The Symbolic Species Evolved. Springer Science & Business Media. ISBN 9789400723351 .
6. Villmoare, Brian (30 Ianuarii 2018). "Early Homo and the role of the genus in paleoanthropology". American Journal of Physical Anthropology 165: 72–89 .
7. "Fossil reveals oldest live birth". BBC. 28 Maii 2008 .
8. Carr, R. K.; Johanson, Z.; Ritchie, A. (2009). "The phyllolepid placoderm Cowralepis mclachlani: Insights into the evolution of feeding mechanisms in jawed vertebrates". Journal of Morphology 270 (7): 775–804 .

Nexus externi

Vicimedia Communia plura habent quae ad Placodermos spectant (Placodermi, Gnathostomata).

• Markussen-Brown, Annetta. 2000. "Devonian Armoured Fish."
• "Introduction to the Placodermi: Extinct armored fishes with jaws."
• "PALAEOZOIC FOSSILS UK." Archivum.
• "Placoderms."
• "Placodermi: Overview."
• De Dunkleosteo terrelli. BBC.