Miacis
Name: Miacis
(Mother animal).
Phonetic: My-ah-sis.
Named By: Edward Drinker Cope - 1872.
Classification: Chordata, Mammalia, Miacoidea.
Species: M. parvivorus (type),
M.
australis, M. cognitus, M. deutschi, M. exiguus, M.
gracilis, M. hargeri, M. hookwayi, M. latidens, M.
medius, M. parvivorus, M. petilus, M. rosei, M.
sylvestris, M. washakius, M. winkleri.
Diet: Carnivore.
Size: Between about 20 and 30 centimetres long,
depending upon the species.
Known locations: Europe, North America, China.
Time period: Ypresian through to Bartonian of the
Eocene.
Fossil representation: Many specimens.
Miacis
is
often heralded as being the progenitor of the Carnivora, one of the
main groups of carnivorous mammals that today include predators such as
big cats, wolves and mustelids among others. However most of the
known species of Miacis are considered to actually
be members of the
Carnivoramorpha, a group of predator mammals that the Carnivora are
descended from, but containing animals that that do not show off of
their hall marks. One reason why most of the species of Miacis
are
not fully included with the Carnivora is because they have forty-four
teeth, whereas most modern members of the Carnivora have around
thirty or even less teeth in some cases.
However
despite most of the
species being classed as close to true members of the Carnivora, one
species called M. cognitus is actually considered
by many to be a
true member of the Carnivora. Although only based upon a skull, M.
cognitus is the first (and so far only known) species
that shows a
reduction in size for the anterior premolars as well as the places for
two teeth, giving the living animal forty-two instead of the
forty-four teeth that are seen in other Miacis
species. This means
that unlike the other species, M. cognitus
displays the beginnings
of dental features that would become recognisable traits in future
members of the Carnivora.
More
complete specimens have
led to the now commonplace analogy of Miacis being
similar to a pine
martin (Martes martes). Although generally
much smaller than a
pine martin, Miacis does have a similar low slung
body with
well-developed fore quarters, particularly the shoulders and leg
joints that would help Miacis to climb up trees.
As such Miacis is
seen as an arboreal predator, which means that it hunted up in the
tree canopy for animals like other small mammals and birds. Miacis
may have also raided nests, eating eggs and chicks of birds, and
the still developing young of other arboreal mammals. While in the
tree canopy Miacis would have been the top predator
in the habitat,
however Miacis would periodically have to move
around on the forest
floor, possibly to hunt, expand into new areas and even drink.
While on the floor Miacis would have been in
danger itself from
creodont mammals like the smaller species of Hyaenodon
that would have
enjoyed a quick Miacis sized snack.
Further reading
- Third account of new Vertebrata from the Bridger Eocene of Wyoming
Valley. - Proceedings of the American Philosophical Society (separate)
1-4. - Edward Drinker Cope - 1872.
- Systematics of Early Eocene Miacidae (Mammalia, Carnivora) in the
Clark's Fork Basin, Wyoming. Contributions from the Museum of
Paleontology, University of Michigan 26(10):197-225. - P. D. Gingerich
- 1983.
- Carnivorous mammals of the Late Eocene and Early Oligocene of
Trans-Pecos Texas. Texas Memorial Museum Bulletin 33:1-66. - E. P.
Gustafson - 1986.
-
Earliest Eocene Miacidae (Mammalia: Carnivora) from northwestern
Wyoming. - Journal of Paleontology. 82 (1): 154–162. - Ronald E.
Heinrich, Suzanne G. Strait & Peter Houde - 2016
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