Hyracotherium

Source: Wikipedia, the free encyclopedia.
Hyracotherium
Temporal range: 55–45 
Ma
BMNH C21361, the second specimen
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Perissodactyla
Family: †Palaeotheriidae
Genus: †Hyracotherium
Owen, 1841
Species
  • †H. leporinum

Hyracotherium (

brontotheres. The remaining species are now thought to belong to different genera, such as Eohippus
, which had previously been synonymised with Hyracotherium.

Description

domestic cat
.

Hyracotherium averaged 78 cm (2.5 feet) in length and weighed about 9 kg (20 pounds).[1] It had a short face with eye sockets in the middle and a short diastema (the space between the front teeth and the cheek teeth). The skull was long, having 44 low-crowned teeth. Although it had low-crowned teeth, the beginnings of the characteristic horse-like ridges on the molars can be seen. Hyracotherium is believed to have been a browsing herbivore that ate primarily soft leaves as well as some fruits and nuts and plant shoots.[2]

Discovery

Holotype BMNH M16336

The first

paleontologist Richard Owen in a paper read to the Geological Society of London on 18 December 1839 as a "small mutilated cranium about the size of that of a hare". He identified it as belonging to an extinct order of Pachydermata, with teeth resembling those of the Chaeropotamus and the general form of the skull "partaking of a character intermediate between that of the hog and the hyrax, though the large size of the eye must have given to the physiognomy of the living animal a resemblance to that of the Rodentia." Referring to this resemblance to the hyrax, Owen proposed the genus name Hyracotherium for this new genus.[3] In his formal description published by the Geological Society in 1841, Owen wrote "Without intending to imply that the present small extinct Pachyderm was more closely allied to the Hyrax than as being a member of the same order, and similar in size, I propose to call the new genus which it unquestionably indicates, Hyracotherium, with the specific name leporinum."[4][5]

In 1876

Clive Forster Cooper. The only species, E. angustidens, was moved to the genus Hyracotherium, which had priority as the name for the genus, with Eohippus becoming a junior synonym of that genus.[5] Many other North American equids were subsequently classified as species of Hyracotherium as well, but this synonymy has recently been questioned.[6]

Taxonomy and evolution

The

Arenahippus, Minippus, Sifrhippus, Xenicohippus, Pliolophus, Protorohippus and the resurrected Eohippus.[6] At one time, Xenicohippus was regarded as an early brontothere. The main stream of horse evolution occurred on the North American continent.[citation needed
]

See also

References

  1. ^ Radinsky (1978). "Evolution of brain size in carnivores and ungulates." American Naturalist: 815–831.
  2. ISSN 0003-0082
    .
  3. ^ Owen, Richard (1840). “Description of the fossil remains of a mammal, a bird, and a serpent, from the London clay.” Proceedings of the Geological Society of London, 3(66): 162–166
  4. ^ Owen, Richard (1841). “Description of the Fossil Remains of a Mammal (Hyracotherium leporinum) and of a Bird (Lithornis vulturinus) from the London Clay. Archived 2020-01-07 at the Wayback Machine” Transactions of the Geological Society of London, Series 2, 6: 203–208
  5. ^ a b Britain, Troy. "Feedback for June 2006". TalkOrigins Archive. Retrieved 4 May 2012.
    A horse is a horse, unless of course… « Playing Chess with Pigeons, 25 May 2008
  6. ^
    doi:10.1046/j.1096-3642.2002.00005.x
    .
  7. doi:10.1006/zjls.1994.1033
    .
Retrieved from "https://en.wikipedia.org/w/index.php?title=Hyracotherium&oldid=1191078381"