A pachyosteomorph arthrodire from Gogo, Western Australia

A new monotypic genus of eubrachythoracid arthrodire is described from die Upper Devonian Gogo Formation of Western Australia as Incisoscutum ritchiei gen. et sp. nov. It is at die pachyosteomorph level of organization, having no contact between the plates of die flank and those of the ventral shield behind the pectoral fin. It is interchangeable widi Coccosteus spp. and a number of earlier described Gogo forms in a sketch dadogram for arthrodires, but its phylogenedc relationships are unknown. Well preserved material of die scapulocoracoid throws new light on die structure of this element in arthrodires, particularly widi respect to variations in die pattern of canals and foramina.

[1]  R. Miles,et al.  New durophagous arthrodires from Gogo, Western Australia , 1980 .

[2]  Robert R. Miller.  Handbook of Paleoichthyology, 2. Placodermi: R. Denison. Gustav Fischer Verlag, Stuttgart, 1978, 128 pp., 94 figs., DM 128.00 , 1980 .

[3]  R. Miles,et al.  Eubrachythoracid arthrodires with tubular rostral plates from Gogo, Western Australia , 1979 .

[4]  R. Miles,et al.  A second eubrachythoracid arthrodire from Gogo, Western Australia , 1979 .

[5]  Gavin Young.  New information on the structure and relationships of Buchanosteus (Placodermi: Euarthrodira) from the Early Devonian of New South Wales , 1979 .

[6]  R. Miles,et al.  A primitive eubrachythoracid arthrodire from Gogo, Western Australia , 1979 .

[7]  R. Miles.  The Holonematidae (Placoderm Fishes), A Review Based on New Specimens of Holonema from the Upper Devonian of Western Australia , 1971 .

[8]  Tor Ørvig.  A NEW BRACHYTHORACID ARTHRODIRE FROM THE DEVONIAN OF DICKSON LAND, VESTSPITSBERGEN , 1969 .

[9]  R. Miles.  VI.—Features of Placoderm Diversification and the Evolution of the Arthrodire Feeding Mechanism. , 1969, Transactions of the Royal Society of Edinburgh.

[10]  T. S. Westoll,et al.  IX.—The Placoderm Fish Coccosteus cuspidatus Miller ex Agassiz from the Middle Old Red Sandstone of Scotland. Part I. Descriptive Morphology , 1968, Transactions of the Royal Society of Edinburgh.

[11]  R. Miles.  XV.—The Placoderm Fish Rhachiosteus pterygiatus Gross and its Relationships , 1966, Earth and Environmental Science Transactions of the Royal Society of Edinburgh.

[12]  Tor Ørvig.  New Finds of Acanthodians, Arthrodires, Crossopterygians, Ganoids and Dipnoans in the Upper Middle Devonian Calcareous Flags (Oberer Plattenkalk) of the Bergisch Gladbach-Paffrath Trough , 1960 .

[13]  E. Stensiö.  On the pectoral fin and shoulder girdle of the arthrodires , 1959 .