The Paleorhynchidae (Fig. 6) comprises five gen- 

 era (Ert«/jA77/e'«M5, Homorhynchus, Hemirhynchus, 

 Paleorhynchus, ana Pseudotetrapturus) that are 

 found from the Eocene to the Oligocene of Europe. 

 One species, Pseudotetrapturus luteus, reaches up 

 to 4 m in length (Danil'chenko, 1960), although other 

 species usually are no longer than 1 m in length. 

 Their vertebral count varies from 45 to 60. Accord- 

 ing to Danirchenko (1960), P. luteus resembles Te- 

 trapturus in dimensions and body form and in the 

 structure of the elongated snout, but it differs from 

 Tetrcipturus in the far greater number of vertebrae, 

 the much longer lower jaw, the more dorsal position 

 of the pectoral fins, and the presence of large scales. 

 Since I feel that the resemblances to the istiophorids 

 are probably a result of convergence, I choose to put 

 them in the Xiphioidei Incertae Sedis. 



The family Xiphiorhynchidae is known from five 

 species found in the Eocene of Africa, America, and 

 Europe. The original description was from cranial 

 fragments and subsequently various rostra were 

 thought to be conspecific with the cranial fragments 

 (Woodward, 1901). The crania (Fig. 10) are similar in 

 proportions to those found in the Istiophoridae. Re- 

 cently the Los Angeles County Museum of Natural 

 History was given a large rostrum and two as- 

 sociated vertebrae (Figs. 11, 12) which belong to a 

 new species of Xiphiorhynchus (Fierstine and Ap- 

 plegate, in press). One vertebra, an abdominal, is 

 similar in size and shape to an abdominal vertebra of 

 a black marlin (Makaira indica), whereas the other 

 vertebra, a caudal, is similar in shape to that of a 

 swordfish. Both vertebrae are strongly ossified like 



^ ' \.¥ 





[Ill|llli|lillhlll{lililllil|llll|llllllllllllll|lil 





tiii|iiii|ini|iiii{iiii|iiii|iiii|iiiiiiiii|iiii|iiii|uiii 



Figure 10. — Semidiagrammatic reconstruction of 

 Xiphiorhynchus prise us. A. Dorsal view of skull. B. 

 Lateral view of opercular region. (From Casier, 1966.) 



Figure 11. — Rostrum oi Xiphiorhynchus sp. from the 

 Eocene of Mississippi. A. Lateral view. B. Dorsal view. C. 

 Ventral view. D. Cross-section taken 220 mm from distal 

 tip. E. Cross-section taken 170 mm from distal tip. 



39 



