A new early devonian petalichthyid fish from the Taemas/Wee Jasper region of New South Wales

Abstract

Wijdeaspis warrooenis sp. nov. is described from the Taemas Limestone near Wee Jasper, N.S.W. Two specimens are referred to the species, an incomplete skull-roof and a spinal plate. The skull fragment shows new details of braincase structure including attachment of the occipital region of the endocranium to the skull-roof over its whole length, and the presence of an endocranial shelf roofing over the cucullaris fossa. These features are regarded as primitive for petalichthyids. A new restoration shows the glenoid processes and foramen magnum to be similarly developed to Kujdanowiaspis, but the high position of the lateral line canal and the absence of a preserved anterior dorsolateral plate preclude an adequate functional interpretation of the neck-joint. Two dermal structures support the posterior region of the endocranium — a paired lateral process may correspond to the brachythoracid para-articular process, and paired depressions on the ventral nuchal lamella resemble the articular fossae in brachythoracids. Show more