A new late devonian bothriolepid (Placodermi, antiarcha) from victoria, with descriptions of other species from the state

A new species of bothriolepid antiarch, Bothriolepis tatongensis sp. nov., from the Late Devonian basal conglomerate of the Hollands Creek Rhyodacite, near Tatong, northern Victoria, is described. B. tatongensis sp. nov. can be distinguished from all other species possessing a trifid preorbital recess by the short postpineal plate with paired pits opening anteriorly into the orbital fenestra, and by coarsely reticulate dermal ornament. B. gippslandiensis Hills, B. cullodenensis Long, B. fergusoni Long, B. bindareei Long and B. warreni Long are described and illustrated. Metric analysis of headshield and premedian plate measurements of B. gippslandiensis, B. cullodenensis and B. fergusoni are compared with ontogenetic variation in B. canadensis Whiteaves. The phylogenetic position of B. fergusoni and B. tatongensis sp. nov. is discussed and the significance of the preorbital recess in bothriolepid evolution re-evaluated. A trifid preorbital recess is suggested to be apomorphic within the Bothriolepidoidei by comparison with the homologous structures in other antiarchs. The composition of the Tatong fauna indicates a late Givetian-early Frasnian age for the base of the Hollands Creek Rhyodacite, and the onset of post-Tabberabberan sedimentation in the southern end of the Lachlan Fold Belt.