Cowralepis, a new genus of phyllolepid fish (Pisces, Placodermi) from the late middle Devonian of New South Wales, Australia

Cowralepis mclachlani, a new genus and species of phyllolepid placoderm (Pisces, Placodermi), is described from numerous articulated specimens discovered near Cowra, New South Wales, Australia. Cowralepis, represented by a growth series, illustrates ontogenetic changes from juvenile to adult and throws new light on the dermal, endocranial, visceral and axial skeleton of phyllolepids and on placoderm interrelation ships. The head shield is longer than the trunk shield, the reverse of the situation in other phyllolepid genera. The presence of two pairs of upper tooth plates, plus a posterior dorsolateral plate, an anterior median ventral plate and one or more posterior median ventral plates in the trunk shield is confirmed. The phyllolepid jaw apparatus and associated structures, first reported in Austrophyllolepis, are reinterpreted. The branchial skeleton, an occipital ossification and a fused synarcual, previously unknown in phyllolepids, are described. Cowralepis had an ossified vertebral column, a large epicercal caudal fin and small pelvic fins but lacked a dorsal fin. The Cowralepis material has suffered regional tectonism and illustrates why tectonic deformation must be taken into account in the interpretation of fossils from ancient fold belts.