Pteraspidiformes

From Palaeos

o Vertebrata
`--o Pteraspidomorphi
   |--Arandaspida
   `--o Heterostracomorphi
      |--Astraspida
      `--Heterostraci
         |--o Cyathaspidiformes
         |  |--Cyathaspidida
         |  `--Amphiaspidida
         `--o Pteraspidiformes
            |--Pteraspididae
            `--Psammosteida
               |--Drepanaspis
               `--Psammosteidae

Information

Range: Late Silurian to Late Devonian

Phylogeny: Heterostraci: Cyathaspidiformes + Pteraspidiformes: Anchipteraspididae + Pteraspidida.

Characters: separate orbital, pineal and rostral plates; single median dorsal spinal plate present; separate branchial and cornual plates; dermal ornamentation of concentric, serrated dentine ridges..

Phylogeny

(the following dendrogram is from Mikko's Phylogeny Archive)

<=o †Pteraspidiformes Berg, 1940
  |--o †Anchipteraspididae
  |  |-- †Anchipteraspis
  |  |-- †Rhachiaspis
  |  `-- †Ulutitaspis
  `--+-- †Protopteraspidae Novitskaya, 1983
     `--o †Pteraspidina Janvier, 1996 [Pteraspidoidei sensu Pernègre, 2006]
        |?-o †Cardipeltis [Cardipeltidae]
        |  `-- †C. bryanti
        |-- †Pteraspididae Claypole, 1885 [Pteraspidae]
        `--+--o †Doryaspis White, 1935[Doryaspididae Heintz, 1967]
           |  |-- †D. nathorsti (Lankester, 1884) [taxonomic history]
           |  |-- †D. minor (Heintz, 1960)
           |  |-- †D. lyktensis (Heintz, 1960)
           |  |-- †D. arctica Pernègre, 2002
           |  `-- †D. sp. [Blieck, et al., 1987]
           `--o †Protaspidoidea
              |--o †Protaspididae Janvier, 1996 [paraphyletic?]
              |  |-- †Xylaspis prima (Pernègre, 2003) Pernègre, 2004 [Spitsbergaspis prima Pernègre, 2003]
              |  |?-o †Gigantaspis Heintz, 1962
              |  |  `-- †G. isachseni Heintz, 1962
              |  `--o †Protaspis [Cyrtaspidichthys, Cyrtaspis, Eucyrtaspis, Europrotaspis, Gigantaspis]
              |     |-- †P. (Cosmaspis) transversa [however, see Pteraspididae]
              |     `-- †P. (Protaspis) erroli
              `-- †Psammosteida [Psammosteidae sensu lato; incl. Drepanaspidae]

Links

• Pteraspidiformes (Mikko's Phylogeny Archive
• Class Pteraspidomorphi
• Heterostraci - Tree of Life Web Project

Credits

• ATW020510.(Palaeos com)
• MH051214 Mikko's Phylogeny Archive (Phylogeny)