684 CARNIVORES xxvn. 5- 



(Fig. 448), retained the triangular molars and became very large, 

 perhaps they were scavenging creatures. Their toes carried hoofs, 

 and this, together with their simple dentition and other features, has 

 suggested to some that smaller members of the group may have been 

 ancestral to the Artiodactyla. Other Eocene creodonts, however, 

 became more typical carnivores, with shearing carnassials, developed 

 from various teeth, often the upper first and lower second molar. 



Fig. 448. The skulls of some early carnivores. 



a, *Mesonyx\ B, *Oxyaena; c, *Sinopa; d, *Vulpavus. a-c are creodonts, D is 



a rniacid fissipede. (After Romer, a after Scott, b and c after Wartmann, and 



D after Matthew.) 



These early carnivores radiated into lines that parallel those found 

 today. Thus *Dromocyon resembled a dog, *Oxyaena an otter, *Dis- 

 sacus a cat, and *Sinopa a weasel. *Hyaenodon and its allies were 

 abundant hyena-like animals of various sizes; they survived until the 

 Eocene. *Apataelurus was an Eocene sabre-tooth. By their similarities 

 to later carnivores these arrays of early carnivore types constitute a 

 remarkable example of convergent evolution. 



After their abundance in the Eocene the creodonts declined, 

 although a few genera survived until the Pliocene. Perhaps the type, 

 though able to catch the cumbrous early herbivores, was unable to 

 make a living from the later, faster-moving ungulates. 



6. Suborder Fissipeda 



Towards the end of the Eocene a new type of carnivore became 

 abundant. The earliest of these, the *Miacidae, were so like creodonts 

 that they are sometimes classified in that group, sometimes with the 

 Fissipeda. Thus miacids of the Eocene (Fig. 448) were small animals, 

 perhaps arboreal, very close to the *Arctocyonidae and still with 



