208 UPPER CRETACEOUS TELEOSTS 
part of the floor are formed of pterotic whilst the medial wall and remainder of the 
floor consist of frontal, parietal and epiotic. Gosline, Marshall and Mead (1966 : 5) 
used the presence of a post-temporal fossa in Aulopus as evidence for an elopoid 
derivation of the myctophiforms, believing a post-temporal fossa to be absent in 
the salmoniforms. As Weitzman (1967 : 528) has indicated this is an erroneous 
interpretation of the nature of a post-temporal fossa, and post-temporal fossae 
are present in most salmoniforms. It has been shown in the fossil salmoniform 
suborders considered in this paper, that the ichthyotringoids and the enchodontoids 
have representatives with completely roofed fossae, while the cimolichthyoids 
have a partially roofed fossa. In the floor of the fossa, near to the posterior edge, 
is a transversely orientated oval fenestra filled with cartilage. 
The epiotic joins the supraoccipital medially both on the roof of the skull and on 
the posterior face. Medial to the opening of the post-temporal fossa the epiotic has 
a prominent dorsal knob which provides the articulatory area for the dorsal limb of 
the post-temporal. 
Fic. 88. Aulopus filamentosus. Neurocranium in lateral view. 
The sphenotic forms the postero-dorsal region of the orbit, contacting the frontal 
dorsally and the pterotic posteriorly. The sphenotic is partially obscured dorsally 
by the last infraorbital. This infraorbital is intimately connected to the edges of 
both the sphenotic and frontal. This intimate connection of the last infraorbital 
with sphenotic and frontal was noticed in Sardinioides (p. 154), and is also seen in 
Nematonotus (Text-fig. 94). 
The hyomandibular facet is formed of sphenotic, pterotic and prootic. The upper 
margin of the facet also forms the ventral border of the dilatator fossa. The facet is 
in two distinct regions, an anterior cup-shaped depression formed mainly of sphenotic 
(with a ventral inclusion from the prootic), and a posterior elongated oval cup within 
the pterotic. 
