Unique dental arrangement in a new species, Groenlandaspis howittensis (Placodermi, Arthrodira) from the Middle Devonian of Mount Howitt, Victoria, Australia.
Well-preserved specimens of a new species of arthrodiran placoderm, Groenlandaspis howittensis sp. nov. (Middle Devonian of Victoria, Australia), reveals previously unknown information on the dermal skeleton, body-shape and dentition of the wide-spread genus Groenlandaspis. The new material includes...
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PeerJ Inc.
2024-12-01
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| author | Austin N. Fitzpatrick Alice M. Clement John A. Long |
| author_facet | Austin N. Fitzpatrick Alice M. Clement John A. Long |
| author_sort | Austin N. Fitzpatrick |
| collection | DOAJ |
| description | Well-preserved specimens of a new species of arthrodiran placoderm, Groenlandaspis howittensis sp. nov. (Middle Devonian of Victoria, Australia), reveals previously unknown information on the dermal skeleton, body-shape and dentition of the wide-spread genus Groenlandaspis. The new material includes dual pineal plates, extrascapular plates, and cheek bones showing the presence of cutaneous sensory organs. The anterior supragnathal, usually a paired element in arthrodires, is a fused median bone in G. howittensis sp. nov. It is positioned anterior to the occlusion of the mouth between the lower jaw (infragnathals) and upper jaw (posterior supragnathals) bones, indicating a specialised feeding mechanism and broadening the known diversity of placoderm dental morphologies. G. howittensis sp. nov. differs from all other groenlandaspidids by a less pronounced posterior expansion of the nuchal plate; the shape of the posterior dorsolateral plate and the presence of a short accessory canal on the anterior dorsolateral plate. A new phylogenetic analysis positions Groenlandaspididae in a monophyly with the phlyctaeniid families Arctolepidae and Arctaspididae, however, the specific intrarelationships of groenlandaspidids remain poorly resolved. |
| format | Article |
| id | doaj-art-d2f472226c3040ad8940a6f33e6317ea |
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| issn | 2167-8359 |
| language | English |
| publishDate | 2024-12-01 |
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| spelling | doaj-art-d2f472226c3040ad8940a6f33e6317ea2025-08-20T02:35:18ZengPeerJ Inc.PeerJ2167-83592024-12-0112e1875910.7717/peerj.18759Unique dental arrangement in a new species, Groenlandaspis howittensis (Placodermi, Arthrodira) from the Middle Devonian of Mount Howitt, Victoria, Australia.Austin N. FitzpatrickAlice M. ClementJohn A. LongWell-preserved specimens of a new species of arthrodiran placoderm, Groenlandaspis howittensis sp. nov. (Middle Devonian of Victoria, Australia), reveals previously unknown information on the dermal skeleton, body-shape and dentition of the wide-spread genus Groenlandaspis. The new material includes dual pineal plates, extrascapular plates, and cheek bones showing the presence of cutaneous sensory organs. The anterior supragnathal, usually a paired element in arthrodires, is a fused median bone in G. howittensis sp. nov. It is positioned anterior to the occlusion of the mouth between the lower jaw (infragnathals) and upper jaw (posterior supragnathals) bones, indicating a specialised feeding mechanism and broadening the known diversity of placoderm dental morphologies. G. howittensis sp. nov. differs from all other groenlandaspidids by a less pronounced posterior expansion of the nuchal plate; the shape of the posterior dorsolateral plate and the presence of a short accessory canal on the anterior dorsolateral plate. A new phylogenetic analysis positions Groenlandaspididae in a monophyly with the phlyctaeniid families Arctolepidae and Arctaspididae, however, the specific intrarelationships of groenlandaspidids remain poorly resolved.https://peerj.com/articles/18759.pdfPlacodermArthrodireDevonianPhylogenetic analysisDentitionMorphology |
| spellingShingle | Austin N. Fitzpatrick Alice M. Clement John A. Long Unique dental arrangement in a new species, Groenlandaspis howittensis (Placodermi, Arthrodira) from the Middle Devonian of Mount Howitt, Victoria, Australia. PeerJ Placoderm Arthrodire Devonian Phylogenetic analysis Dentition Morphology |
| title | Unique dental arrangement in a new species, Groenlandaspis howittensis (Placodermi, Arthrodira) from the Middle Devonian of Mount Howitt, Victoria, Australia. |
| title_full | Unique dental arrangement in a new species, Groenlandaspis howittensis (Placodermi, Arthrodira) from the Middle Devonian of Mount Howitt, Victoria, Australia. |
| title_fullStr | Unique dental arrangement in a new species, Groenlandaspis howittensis (Placodermi, Arthrodira) from the Middle Devonian of Mount Howitt, Victoria, Australia. |
| title_full_unstemmed | Unique dental arrangement in a new species, Groenlandaspis howittensis (Placodermi, Arthrodira) from the Middle Devonian of Mount Howitt, Victoria, Australia. |
| title_short | Unique dental arrangement in a new species, Groenlandaspis howittensis (Placodermi, Arthrodira) from the Middle Devonian of Mount Howitt, Victoria, Australia. |
| title_sort | unique dental arrangement in a new species groenlandaspis howittensis placodermi arthrodira from the middle devonian of mount howitt victoria australia |
| topic | Placoderm Arthrodire Devonian Phylogenetic analysis Dentition Morphology |
| url | https://peerj.com/articles/18759.pdf |
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