New information on the head and shoulder girdle of Canowindra grossi Thomson, from the Late Devonian Mandagery Sandstone, New South Wales

Abstract

The head of Canowindra grossi is redescribed from newly prepared casts of the holotype. The cheek has a fractionated postorbital series consisting of one large and two small postorbital bones; the lachrymal is small relative to the postorbitals and jugal, and the jugal is elongate. The opercular is deep, and higher than long. The skull table features a parietal shield without differentiated intertemporal, supratemporal or parietal bones. Canowindra shares with osteolepids plus eusthenopterids (Osteolepiformes) a large, externally ornamented anocleithrum, and a cheek with bar-like, vertical preopercular and single, large squamosal bone. It differs from these groups in the structure of the postorbital series and skull roof table. Canowindra represents an endemic genus which should be regarded as the only member of a taxon equivalent to osteolepids plus eusthenopterids. An amended diagnosis of the genus is given.