Name: Theosodon
(God tooth).
Phonetic: Fee-oh-so-don.
Named By: Florentino Ameghino - 1887.
Classification: Chordata, Mammalia, Litopterna,
Macraucheniidae.
Species: T. arozquetai, T. fontanae, T.
frenguellii, T. garretorum, T. gracilis, T. karaikensis, T. lydekkeri,
T. patagonicum, T. pozzi.
Diet: Herbivore.
Size: 2 meters long.
Known locations: South America.
Time period: Aquitanian through to Serravallian of
the Miocene.
Fossil representation: Several specimens.
Theosodon
was probably a lot like a llama in appearance, however it was not
actually related to this group of mammals (the Camelidae) but
instead was a litoptern mammal, the dominant group of mammals in
South America before it became joined to North America. This is a
case of convergent evolution where even though the animal is
unrelated, it still develops similar features and appearance in order
to cope with the same survival challenges. Others of this group like
Diadiaphorus
became more like primitive horses like Mesohippus
in North
America, while other forms like Macrauchenia
became more like camels
albeit with some unusual features. In fact Theosodon
is sometimes
considered as being the ancestor to Macrauchenia.
Theosodon
is noted for having a narrow jaw with a full complement of forty-four
teeth, the maximum number that are known for placental mammals,
although often mammals are known to have less, especially in later
more advanced forms. Like the related Macrauchenia,
Theosodon might
have been a generalist herbivore that both browsed vegetation and
grazed grass. Although two meters long, Theosodon
was within the
predatory scope of marsupials like Borhyaena,
but was already in
decline if not gone by the time the sabre-toothed Thylacosmilus
appeared. An even greater threat however would have come from large
phorusrhacid
terror birds like Phorusrhacos
and Kelenken
that would
have easily had both the speed and killing power to take down an animal
the size of Theosodon. It is also worth noting
that the decline of
Theosodon does seem to coincide with the rise of
large phorusrhacids.
Further reading
- Nuevos restos de mam�feros f�siles descubiertos por Carlos Ameghino
en el Eoceno inferior de la Patagonia austral. – Especies nuevas,
adiciones y correcciones [New remains of fossil mammals discovered by
Carlos Ameghino in the lower Eocene of southern Patagonia. – New
species, additions, and corrections]. - Revista Argentina de Historia
Natural 1:289-328. - F. Ameghino - 1891.
- Nuevas especies de mam�feros, cret�ceos y terciarios de la Rep�blica
Argentina [New species of mammals, Cretaceous and Tertiarty, from the
Argentine Republic]. Anales de la Sociedad Cientifica Argentina
56–58:1-142. - F. Ameghino - 1904.
- Theosodon pozzi n. sp. El mayor theosodonte
Santacruceano. Physis
326-327. - L. Kraglievich & L. J. Parodi - 1931.
- Taxonomic Reinterpretation of Theosodon hystatus
Cabrera and
Kraglievich, 1931 (Litopterna, Macraucheniidae) and Phylogenetic
Relationships of the Family. - Journal of Vertebrate Paleontology. 34
(5): 1231–1238. - Gabriela I. Schmidt & Brenda S. Ferrero -
2014.
- Two new macraucheniids (Mammalia: Litopterna) from the late middle
Miocene (Laventan South American Land Mammal Age) of Quebrada Honda,
Bolivia. - Journal of Vertebrate Paleontology 38(3):e1461632. - A. J.
McGrath, F. Anaya & D. A. Croft - 2018.