FOSSIL AND RECENT 



77 



SOC 



fahm 



exo 



15mm 



Fig. 40. Protarpon cf. priscus. Neurocranium, posterior view of dorsal third. 

 From B.M.N.H. P.4153. 



Appendix to Protarpon priscus 



B.M.N.H. P. 4153 was considered to be Megalops priscus by Woodward (1901 : 

 26, pi. 3, fig. 6) and Casier (1966: 118). This specimen consists of the rear part 

 of a neurocranium and although incomplete, it differs somewhat from the typical 

 P. priscus. In dorsal view not only is the skull roof relatively wider at the sphenotic 

 level, but the widest point of the neurocranium occurs towards the posterior end of 

 the hyomandibular facet, and not, as in P. priscus, at the sphenotic level. The 

 parietals are relatively smaller and exhibit a characteristic ' waisted ' appearance. 

 In posterior view the openings of the post-temporal fossae are circular and not 

 vertically elongated as in P. priscus. 



Laterally the neurocranium (Woodward 1901 : pi. 3 fig. 6) shows a large, deep 

 dilatator fossa containing a large foramen which probably communicated with the 

 post-temporal fossa. The hyomandibular facet is divided into anterior and posterior 

 oval depressions, linked by an extremely narrow ledge of bone. Finally, the sub- 

 temporal fossa appears slightly smaller in area, resembling that of Megalops. 



The points mentioned are at variance with the neurocranial details seen in the 

 (admittedly few) specimens of P. priscus and appear sufficient to remove this speci- 

 men (P. 4153) from P. priscus. However, apart from the neurocranium nothing 

 else is known about this form and in consequence it would not be justifiable to erect 

 a new species for it. Pending a better knowledge of the ontogenetic and individual 

 variation of P. priscus (which could only be gained by more specimens) and/or more 

 complete material of forms like P.4153, it seems best to regard this specimen as a 

 form very much like P. priscus but possibly representing a different species. 



