The Palaeomerycidae are an extinct
family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
of
ruminants
Ruminants (suborder Ruminantia) are hoofed herbivorous grazing or browsing mammals that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through microbial actions. The ...
in the
order Artiodactyla
The even-toed ungulates (Artiodactyla , ) are ungulates—hoofed animals—which bear weight equally on two (an even number) of their five toes: the third and fourth. The other three toes are either present, absent, vestigial, or pointing poster ...
. Palaeomerycids lived in
North America,
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...
,
Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
and
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...
from 33 to 4.9 million years ago (from the Late
Eocene
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ...
to
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58[South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...](_blank)
, but its identity as a palaeomerycid was subsequently disputed.
Specimens of ''
Amphitragulus'', the earliest known genus, have been found in
Aragon (
Spain
, image_flag = Bandera de España.svg
, image_coat = Escudo de España (mazonado).svg
, national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond")
, national_anthem = (English: "Royal March")
, i ...
),
Ronheim (Germany),
Sardinia
Sardinia ( ; it, Sardegna, label=Italian, Corsican and Tabarchino ; sc, Sardigna , sdc, Sardhigna; french: Sardaigne; sdn, Saldigna; ca, Sardenya, label=Algherese and Catalan) is the second-largest island in the Mediterranean Sea, after ...
(
Italy
Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...
),
France
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of overseas regions and territories in the Americas and the Atlantic, Pacific and Indian Oceans. Its metropolitan area ...
, and
Kazakhstan
Kazakhstan, officially the Republic of Kazakhstan, is a transcontinental country located mainly in Central Asia and partly in Eastern Europe. It borders Russia to the north and west, China to the east, Kyrgyzstan to the southeast, Uzbeki ...
and range from 33 to 15.97 million years old. Fossils of ''
Lagomeryx'' and ''
Palaeomeryx feignouxi'' were recovered in
Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
and
Slovakia
Slovakia (; sk, Slovensko ), officially the Slovak Republic ( sk, Slovenská republika, links=no ), is a landlocked country in Central Europe. It is bordered by Poland to the north, Ukraine to the east, Hungary to the south, Austria to the s ...
from the Middle Eocene.
The oldest known North American specimen, ''
Barbouromeryx'', was discovered in
Scotts Bluff, Nebraska, and estimated at 23.03 million years old. Palaeomerycids such as ''
Cranioceras'' and other
Dromomerycinae continued to live in North America until the early Pliocene.
Description
![Dromomeryx](https://upload.wikimedia.org/wikipedia/commons/6/63/Dromomeryx.jpg)
Palaeomerycids were a group of horned, long-legged and massive ruminants that could attain a weight of .
One of the first known members of this group, ''
Palaeomeryx'', was thought to be a hornless form distantly related to the
Giraffidae
The Giraffidae are a family of ruminant artiodactyl mammals that share a common ancestor with deer and bovids. This family, once a diverse group spread throughout Eurasia and Africa, presently comprises only two extant genera, the giraffe (one ...
before paleontologist
Miguel Crusafont found remains of ''
Triceromeryx'' in middle Miocene Spain. This ''Palaeomeryx''-like form carried two
ossicone
Ossicones are columnar or conical skin-covered bone structures on the heads of giraffes, male okapi, and some of their extinct relatives. Ossicones are distinguished from the superficially similar structures of horns and antlers by their uniqu ...
s over its orbits that were straight and short, similar to those of true giraffids. However, the most striking feature of ''Triceromeryx'' was the third, Y-shaped appendage that prolonged the
occipital bone at the back of the skull. Discoveries during the 1980s and 1990s showed a surprising variety in these occipital appendages.
''
Ampelomeryx'', a genus of palaeomerycids found at the early Miocene site of
Els Casots,
Valles-Penedes Basin, Spain, had a three-horned system of appendages similar to those of ''Triceromeryx''. These appendages were, however, quite different, with the paired appendages extending laterally over the orbits, flat and wide, forming an eye-shade, while the third spectacular posterior appendage was about long.
Another species of ''Triceromeryx'', ''
T. conquensis'' found in
La Retama in Spain, showed an even more spectacular appendage — instead of a Y-shaped structure, its posterior appendage was T-shaped with the lateral branches expanding toward the front.
In primitive members of the group (e.g. ''Ampelomeryx''), this appendage was a posterior expansion of the occipital bone lying close to the powerful muscles supporting the skull in a normal position, thus suggesting that this appendage was actually used for fighting between males during the breeding season. The reduced shapes of the flat and laterally oriented appendages of later species suggests that these were not used in active fighting, instead forming a function of passive display.
The limbs were more similar to those of modern large
bovid
The Bovidae comprise the biological family of cloven-hoofed, ruminant mammals that includes cattle, bison, buffalo, antelopes, and caprines. A member of this family is called a bovid. With 143 extant species and 300 known extinct species, ...
s (e.g.
buffaloes) than to those of
okapi
The okapi (; ''Okapia johnstoni''), also known as the forest giraffe, Congolese giraffe, or zebra giraffe, is an artiodactyl mammal that is endemic to the northeast Democratic Republic of the Congo in central Africa. It is the only species ...
s. They probably lived in boggy forests, living on soft leaves and aquatic plants (as hinted to by the
brachydont
The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone to ...
teeth, which are similar to those of primitive giraffids). Their diets consisted of coarse plant material.
As a group, the palaeomerycids appear to have formed a successful part of an independent radiation of horned ruminants that diversified into a variety of forms during the early to middle Miocene, with a geographic range reaching from Spain to China. The giraffids seem to have originated in Asia south of the
Alpine belt, while the cervoids seem to have originated north of the Alpine belt.
Taxonomy
![Xenokeryx amidalae restoration](https://upload.wikimedia.org/wikipedia/commons/f/fb/Xenokeryx_amidalae_restoration.jpg)
The Palaeomerycidae were named by Lydekker (1883). The type genus is ''Palaeomeryx''. The family was assigned to the Artiodactyla by Hulbert and Whitmore (2006), and to Cervoidea by Carroll (1988), Sach and Heizmann (2001) and Prothero and Liter (2007).
Classification
*''
Amphitragulus''
*
Dromomerycinae
**''
Asiagenes''
**
Aletomerycini
***''
Sinclairomeryx''
***''
Aletomeryx''
***''
Surameryx''? – interpretation as a palaeomerycid disputed
***''
Diabolocornis''
**
Dromomerycini
***''
Drepanomeryx''
***''
Rakomeryx''
***''
Dromomeryx''
***''
Subdromomeryx''
**
Cranioceratini
***''
Barbouromeryx''
***''
Bouromeryx''
***''
Procranioceras''
***''
Cranioceras''
***''
Pediomeryx''
***''
Yumaceras''
![Lagomeryx](https://upload.wikimedia.org/wikipedia/commons/b/b4/Lagomeryx.JPG)
*
Palaeomerycinae
**''
Ampelomeryx''
**''
Palaeomeryx''
**''
Triceromeryx''
**''
Xenokeryx''
Genus ''
Lagomeryx'' (together with its proposed subfamily Lagomerycinae) may be a further member of this family, as well as ''
Ligeromeryx'' and ''
Stephanocemas'' (formerly classified as members of
Cervidae
Deer or true deer are hoofed ruminant mammals forming the family Cervidae. The two main groups of deer are the Cervinae, including the muntjac, the elk (wapiti), the red deer, and the fallow deer; and the Capreolinae, including the reind ...
).
References
External links
*
{{Taxonbar, from=Q5493096
Eocene first appearances
Miocene extinctions
Prehistoric mammal families
Pecora