Canidae
Dog or fox-like mammals
Canidae - Dog or fox-like mammals, canids are familiarly dog-like, with straight, level backs, long, slender legs, large ears and long muzzles. All are built to run but many also use stealth and pouncing to secure birds and small mammals. Essentially monogamous, canids are unique among carnivores in regurgitating meat to feed pups and other non-hunting family members.
Although taxonomically diverse today, the geographically and ecologically broad distribution of canids is a relatively recent phenomenon. Prior to the latest Miocene (Hemphillian), all canids were restricted to North America where their members were more diverse in size, and presumably habit, than they are today. Canids first appeared in late Middle Eocene and went through three major successive and partly overlapping radiations. In the White River Badlands, the primitive Hesperocyon is the earliest canid of the North America and survived through the late Arikareean. The size of a small fox, later representatives of three different lineages would be much larger, occupying both predatory and scavenging niches. Regardless, early canid evolution was shaped by the spread of savanna and grassland environments as more tropical environments with their forest and woodland habitats gave way to transitional grassland and then arid vegetative regimes. Most modern taxa of canids did not appear until the Pliocene.
This family seems strikingly similar to that of the creodonts (hyaenodons), however there are some crucial differences. True canids occupy a place somewhere between the primitive creodonts and the more advanced nimravids and felids. These differences are seen in their smaller brain size and more cat-like claws and foot structure. Some canids have even been found with retractable claws. The overall body of the Canidae is more adapted for running, with an arched back and long tail.
The Canidae of the White River fauna show similarities to modern day raccoons and foxes, and show a great variation in size. Cynodictis gregarious was the size of a tiny fox, Daphoenus felinus that of a coyote, and Daphoenus superbus that of a wolf. A few such as Ischyrocyon hyaenodus were huge, approaching the size of a modern day grizzly bear. Due to their bone structure, White River canids were probably fast running, wolf-like predators.
Although taxonomically diverse today, the geographically and ecologically broad distribution of canids is a relatively recent phenomenon. Prior to the latest Miocene (Hemphillian), all canids were restricted to North America where their members were more diverse in size, and presumably habit, than they are today. Canids first appeared in late Middle Eocene and went through three major successive and partly overlapping radiations. In the White River Badlands, the primitive Hesperocyon is the earliest canid of the North America and survived through the late Arikareean. The size of a small fox, later representatives of three different lineages would be much larger, occupying both predatory and scavenging niches. Regardless, early canid evolution was shaped by the spread of savanna and grassland environments as more tropical environments with their forest and woodland habitats gave way to transitional grassland and then arid vegetative regimes. Most modern taxa of canids did not appear until the Pliocene.
This family seems strikingly similar to that of the creodonts (hyaenodons), however there are some crucial differences. True canids occupy a place somewhere between the primitive creodonts and the more advanced nimravids and felids. These differences are seen in their smaller brain size and more cat-like claws and foot structure. Some canids have even been found with retractable claws. The overall body of the Canidae is more adapted for running, with an arched back and long tail.
The Canidae of the White River fauna show similarities to modern day raccoons and foxes, and show a great variation in size. Cynodictis gregarious was the size of a tiny fox, Daphoenus felinus that of a coyote, and Daphoenus superbus that of a wolf. A few such as Ischyrocyon hyaenodus were huge, approaching the size of a modern day grizzly bear. Due to their bone structure, White River canids were probably fast running, wolf-like predators.
Taxa of Canids listed by abundance
Cynodictis gregarius (medium fox sized type)
Daphoenus felinus (large coyote sized type)
Hysperocyon gregarius (small fox sized type)
Daphoenus superbus (large wolf sized uncommon type)
Ischyrcyon hyaenodus (very large and rare bear sized type)
Dahpoenus dodgei (Scott 1898 Lower Oligocene type)
OBSOLETE TYPES
Daphoenus dodgei (Lower zone Titanothere zone)
Daphoenus vetus, D. hartshornianus, D. nebrasecnsis, D. inflatus, Cynodictis lippincottianus (Middle Oligocene, Oreodont zone)
Cynodictis temnodon (Upper Oligocene, Protoceras zone)
Daphoenus felinus (large coyote sized type)
Hysperocyon gregarius (small fox sized type)
Daphoenus superbus (large wolf sized uncommon type)
Ischyrcyon hyaenodus (very large and rare bear sized type)
Dahpoenus dodgei (Scott 1898 Lower Oligocene type)
OBSOLETE TYPES
Daphoenus dodgei (Lower zone Titanothere zone)
Daphoenus vetus, D. hartshornianus, D. nebrasecnsis, D. inflatus, Cynodictis lippincottianus (Middle Oligocene, Oreodont zone)
Cynodictis temnodon (Upper Oligocene, Protoceras zone)