232 UPPER CRETACEOUS TELEOSTS 
All of the groups mentioned above except the Beryciformes are included within the 
Protacanthopterygii (sensu Greenwood, et al., 1966), whose basal stock is represented 
by the salmonoids. From a caudal skeleton like that of Salmo (Text-fig. 81) all of 
these other groups can be derived by the fusion of preural vertebra one with ural 
vertebra one. The basic caudal composition of the Enchodontoidei, Cimolich- 
thyoidei, Halecoidei, Myctophiformes, Ctenothrissiformes and Beryciformes is as 
follows : 
Preural vertebra one fused with ural vertebra one. 
Ural two present as a terminal half-centrum. 
Six hypurals. 
Three epurals. 
A stegural formed from uroneural one and neural arch components. 
A second uroneural behind the stegural. 
Soe ear 
A variable feature in the caudal skeleton of these six groups is concerned with the 
neural arch and spine of the second preural vertebra (i.e. the first free preural 
vertebra). In the Beryciformes, Patterson (1968b) states that the polymixoids 
and some dinopterygoids retain the neural spine of preural vertebra two while in 
the remaining dinopterygoids and the berycoids the spine is lost. .In the Cteno- 
thrissiformes, Ctenothrissa, Aulolepis and Pattersonichthys have lost the neural spine, 
and it is only retained in Pateroperca. 
Thus in respect of the post-temporal fossa Pattersonichthys is closest to the ancestry 
of the beryciforms, but in caudal structure is further removed than Pateroperca. 
Patterson’s (1964) conclusions are still valid in that no so far described cteno- 
thrissiform could have been directly ancestral to the beryciforms, although this 
ancestry clearly lies within the ctenothrissiform grade. 
Patterson (1964 : 465) has also used the distribution in time of the ctenothrissi- 
forms as supporting evidence that the group is near the ancestry of the Acantho- 
pterygii as a whole. The more generalized members of the Ctenothrissiformes, 
which are rare in the Cenomanian, have died out by the Turonian, being replaced by 
the more specialized beryciforms which they had given rise to in the Albian or earlier 
(Patterson, 1967a : 107). The more specialized Ctenothrissa, which parallels the 
beryciforms to a certain extent, seemed able to compete with the berycoids and 
continued into the Turonian. This distribution is to be expected if the more 
generalized ctenothrissiform stock (represented by Awlolepis, Pateroperca and 
Pattersonichthys) had given rise to the Beryciformes. 
Patterson (1964) has evaluated the merits of deriving the Acanthopterygii from 
the Ctenothrissiformes or from the Myctophiformes, and has shown conclusively that 
the ancestral stock lies closer to the ctenothrissiforms. He further indicated that 
the Ctenothrissiformes were not closely related to the generalized Myctophiformes 
although both groups had reached the same stage of evolution. As has already been 
indicated in the discussion of the myctophiforms both of these groups are far more 
closely related than Patterson (1964) supposed. Furthermore it has also been 
indicated that the bases of both groups are little removed from a basal salmoniform 
