30 
teeth in each row (Fig. 1b & c). The teeth were conical and pointed 
with little wear. Five dentinal layers were counted from sectioned 
teeth and the pulp cavity was open. The premaxillaries were in 
contact for almost the entirety of the rostrum length, with only a 
small section of the vomer exposed. Storage of the specimen in a dry 
environment, however, has subsequently caused the premaxillaries 
to gape (Fig. 1d). The premaxillaries were roughened dorsally 
where they met the less dense maxillaries, at the base of the nasal 
aperture. The posterior extremity of the rounded, right, premaxillary 
extended to the anterior of the nasal aperture, whereas the pointed 
left premaxillary was truncated at the mid-margin of the opening. 
The premaxillaries, therefore, encircled two thirds of the aperture, in 
L.J. PORTER 
which each nasal passage was deep-set and elliptical. The antorbital 
notch was not developed. The two occipital condyle margins were 
sharply defined and the anterior margin pointed. The channel between 
the condyles was long and triangular. The foramen magnum was 
ovoid with a slightly extended dorsal margin (Fig. 2a). Both the 
temporal and post-temporal fossae were ovoid with sharply-defined 
margins. The temporal fossae protruded where they met which, in 
ventral view, gave the cranium a relatively broad appearance. The 
orbits were rounded and the lacrimals, positioned at right angles to 
the orbit, were blunt with prominent dorsal ridges. The cranial 
articulating surface of the atlas was broad with short, transverse 
processes and a robust, relative to the rest of the vertebrae, neural 

Fig. 3 The a, vertebral column; b, vertebral ribs and c, sternal and free floating ribs of the neotype of Sousa chinensis 
