Borophagus secundus
Encyclopedia
Borophagus secundus is an extinct species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Borophagus
Borophagus
Borophagus is an extinct genus of the subfamily Borophaginae, a group of canids endemic to North America from the early Miocene epoch through the Zanclean stage of the Pliocene epoch 23.3—3.6 Mya. Borophagus existed for approximately .-Overview:Borophagus, like other borophagines, are loosely...

 of the subfamily Borophaginae
Borophaginae
The subfamily Borophaginae is an extinct group of canids called "bone crushing dogs" that were endemic to North America during the Oligocene to Pliocene and lived roughly 36—2.5 million years ago and existing for approximately .-Origin:...

, a group of canids endemic to North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

 from the Early Miocene
Early Miocene
The Early Miocene is a sub-epoch of the Miocene Epoch made up of two stages: the Aquitanian and Burdigalian stages....

 epoch (23.0 Mya) through the Late Miocene
Late Miocene
The Late Miocene is a sub-epoch of the Miocene Epoch made up of two stages. The Tortonian and Messinian stages comprise the Late Miocene sub-epoch....

 epoch (5.3 Mya). Borophagus secundus existed for approximately .

Overview

Borophagus secundus, like other Borophaginae, are loosely known as "bone-crushing" or "hyena
Hyena
Hyenas or Hyaenas are the animals of the family Hyaenidae of suborder feliforms of the Carnivora. It is the fourth smallest biological family in the Carnivora , and one of the smallest in the mammalia...

-like" dogs. Though not the most massive borophagine by size or weight, it had a more highly-evolved capacity to crunch bone than earlier, larger genera such as Epicyon
Epicyon
Epicyon is a large extinct canid genus of the subfamily Borophaginae , native to North America. It lived from the Hemingfordian age of the Early Miocene to the Hemphillian of the Late Miocene Epicyon ("near dog") is a large extinct canid genus of the subfamily Borophaginae ("bone-crushing dogs"),...

, which seems to be an evolutionary trend of the group (Turner, 2004). During the Pliocene epoch, Borophagus began being displaced by Canis genera such as Canis edwardii
Canis edwardii
Canis edwardii is an extinct species of Canidae which was endemic to most of North America from the Blancan stage of the Pliocene epoch through to the Irvingtonian stage of the Pleistocene epoch, living 4.9 Mya—300,000 years ago, existing for approximately...

 and later by Canis dirus. Early species of Borophagus were placed in the genus Osteoborus until recently, but the genera
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 are now considered synonyms. Borophagus diversidens possibly led a hyena-like lifestyle scavenging carcasses of recently dead animals.

Taxonomy

Typical features of this genus are a bulging forehead and powerful jaws; it was probably a scavenger
Scavenger
Scavenging is both a carnivorous and herbivorous feeding behavior in which individual scavengers search out dead animal and dead plant biomass on which to feed. The eating of carrion from the same species is referred to as cannibalism. Scavengers play an important role in the ecosystem by...

. Its crushing premolar
Premolar
The premolar teeth or bicuspids are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant, making eight premolars total in the mouth. They have at least two cusps. Premolars can be considered as a 'transitional tooth' during chewing, or...

 teeth and strong jaw muscles would have been used to crack open bone, much like the hyena of the Old World. The adult animal is estimated to have been about 80 cm in length, similar to a coyote
Coyote
The coyote , also known as the American jackal or the prairie wolf, is a species of canine found throughout North and Central America, ranging from Panama in the south, north through Mexico, the United States and Canada...

, although it was much more powerfully built.

Morphology

Two fossil specimens of Borophagus secundus were measured by Legendre and Roth in 1988. They estimated that specimen one weighed 41 kg (90.3 lbs) and the second weighed 36.1 kg (79.5 lbs).

Fossil distribution

Borophagus secundus fossil specimens are very widespread from Honduras
Honduras
Honduras is a republic in Central America. It was previously known as Spanish Honduras to differentiate it from British Honduras, which became the modern-day state of Belize...

 and El Salvador
El Salvador
El Salvador or simply Salvador is the smallest and the most densely populated country in Central America. The country's capital city and largest city is San Salvador; Santa Ana and San Miguel are also important cultural and commercial centers in the country and in all of Central America...

 to central Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

, Oklahoma panhandle
Oklahoma Panhandle
The Oklahoma Panhandle is the extreme western region of the state of Oklahoma, comprising Cimarron County, Texas County, and Beaver County. Its name comes from the similarity of shape to the handle of a cooking pan....

, central and southern California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

, Nebraska
Nebraska
Nebraska is a state on the Great Plains of the Midwestern United States. The state's capital is Lincoln and its largest city is Omaha, on the Missouri River....

, Kansas
Kansas
Kansas is a US state located in the Midwestern United States. It is named after the Kansas River which flows through it, which in turn was named after the Kansa Native American tribe, which inhabited the area. The tribe's name is often said to mean "people of the wind" or "people of the south...

, and northern New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...

.

Species

  • Borophagus diversidens
    Borophagus diversidens
    Borophagus diversidens is an extinct species of the genus Borophagus of the subfamily Borophaginae, a group of canids endemic to North America from the early Miocene epoch through the Pliocene epoch 4.9—1.8 Ma. Borophagus dudleyi existed for approximately .-Overview:Borophagus diversidens was...

     existed for (synonymous with Felis hillianus, Hyaenognathus matthewi, Hyaenognathus pachyodon, Hyaenognathus solus, Porthocyon dubius)
  • Borophagus dudleyi
    Borophagus dudleyi
    Borophagus dudleyi is an extinct species of the genus Borophagus of the subfamily Borophaginae, a group of canids endemic to North America from the late Hemphillian of the Miocene epoch through the Pliocene epoch...

     existed for
  • Borophagus hilli
    Borophagus hilli
    Borophagus hilli is an extinct species of the genus Borophagus of the subfamily Borophaginae, a group of canids endemic to North America from the early Miocene epoch through the Pliocene epoch . Borophagus dudleyi existed for approximately .-Overview:Borophagus hilli was named by C. S. Johnston...

     existed for (synonymous with Osteoborus crassapineatus, Osteoborus progressus)
  • Borophagus littoralis
    Borophagus littoralis
    Borophagus littoralis is an extinct species of the genus Borophagus of the subfamily Borophaginae, a group of canids endemic to North America from the early Miocene epoch through the Pliocene epoch...

     existed for (syn. Osteoborus diabloensis)
  • Borophagus orc
    Borophagus orc
    Borophagus orc is an extinct species of the genus Borophagus of the subfamily Borophaginae, a group of canids endemic to North America from the late Zanclean stage of the Pliocene epoch through the Hemphillian stage of the Miocene epoch...

     existed for
  • Borophagus parvus
    Borophagus parvus
    Borophagus parvus is an extinct species of the genus Borophagus, of the subfamily Borophaginae, a group of canids endemic to North America from the late Hemphillian of the Miocene epoch through the Pliocene epoch 10.3—4.9 Ma., existing for approximately .-Overview:Borophagus, like other...

     existed for
  • Borophagus pugnator
    Borophagus pugnator
    Borophagus pugnator is an extinct species of the genus Borophagus of the subfamily Borophaginae, a group of canids endemic to North America from the early Miocene epoch through the late Miocene epoch 23.3—4.9 Ma...

    existed for (synonymous with Osteoborus galushai)

Existence based on age of fossil collections and recombination with other species.

Further reading



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