''Alcidedorbignya'' is an extinct

pantodont Pantodonta is an extinct suborder (or, according to some, an order) of eutherian mammals. These herbivorous mammals were one of the first groups of large mammals to evolve (around 66 million years ago) after the end of the Cretaceous. The last ...

mammal known from the

Early Paleocene The Danian is the oldest age or lowest stage of the Paleocene Epoch or Series, of the Paleogene Period or System, and of the Cenozoic Era or Erathem. The beginning of the Danian (and the end of the preceding Maastrichtian) is at the Cretaceo ...

(

Tiupampan The Tiupampan ( es, Tiupampense) age is a period of geologic time (64.5–62.5 Ma) within the Paleocene epoch of the Paleogene used more specifically with South American land mammal ages (SALMA). It is the oldest SALMA age and precedes the Peligr ...

SALMA The South American land mammal ages (SALMA) establish a geologic timescale for prehistoric South American fauna beginning 64.5 Ma during the Paleocene and continuing through to the Late Pleistocene (0.011 Ma). These periods are referred to as a ...

, )

Santa Lucia Formation Santa Claus, also known as Father Christmas, Saint Nicholas, Saint Nick, Kris Kringle, or simply Santa, is a legendary figure originating in Western Christian culture who is said to bring children gifts during the late evening and overnigh ...

(, paleocoordinates ) at Tiupampa near

Mizque Mizque, Misk'i (from Quechua: ''misk'i'', meaning "sweet") is a town in the Cochabamba Department, Bolivia. It is the capital of the Mizque Province. Mizque is located in the valley of the Mizque River, one of the main tributaries of the Río Gr ...

Cochabamba Cochabamba ( ay, Quchapampa; qu, Quchapampa) is a city and municipality in central Bolivia in a valley in the Andes mountain range. It is the capital of the Cochabamba Department and the fourth largest city in Bolivia, with a population of 63 ...

Bolivia , image_flag = Bandera de Bolivia (Estado).svg , flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center , flag_alt2 = 7 × 7 square p ...

. Following a naming convention established by pioneering Argentine palaeontologist

Florentino Ameghino Florentino Ameghino (born Giovanni Battista Fiorino Giuseppe Ameghino September 19, 1853 – August 6, 1911) was an Argentine naturalist, paleontologist, anthropologist and zoologist, whose fossil discoveries on the Argentine Pampas, especially ...

(i.e. combining the first name and surname of a prominent scientist), the genus name honours French naturalist

Alcide d'Orbigny Alcide Charles Victor Marie Dessalines d'Orbigny (6 September 1802 – 30 June 1857) was a French naturalist who made major contributions in many areas, including zoology (including malacology), palaeontology, geology, archaeology and anthrop ...

Description

Estimated 25 cm head-body length and 500 grams, this was a small squirrel sized animal, terrestrial with possible scansorial habits, and either herbivorous or omnivorous. ''Alcidedorbignya'' is one of the oldest and most primitive of the pantodonts and the only pantodont genus known from South America. Not only have some scientists questioned the age of the type locality, instead advocating an Asian origin for the pantodonts, ''Alcidedorbignya'''s bare existence obscures the origins of the already enigmatic pantodonts. Taxonomic similarities indicate that there was a mammalian interchange between North and South America during the early Paleocene, and the North American pantodont '' Pantolambda'' is a potential descendant of ''Alcidedorbignya''. ''Alciddedorbignya'' is known from several specimens of upper and lower dentitions, including juveniles. P^3–4 have V-shaped ectolophs (ridges on the crowns), indicating it was a primitive pantodont. Other molar characteristics makes it unique among pantodonts. On the molars, the paracone and metacone are separated and not connate as in ''

Bemalambda ''Bemalambda'' is an extinct mammal, belonging to the pantodonts. It lived in the lower-middle Paleocene (about 63–58 million years ago) and the fossil remains have been found in China. Description It was a medium-size animal, and could re ...

'' and '' Harpyodus''. As in these two genera, there is neither a mesostyle on M^1–2 nor a strongly V-shaped centocrista as in eupantodonts (all later pantodonts). It is still unclear which the primitive condition is in pantodont upper dentition, and the position of ''Alcidedorbignya'' near the base of the clade remain unresolved.

References

Bibliography

* * * * * * {{Taxonbar, from=Q15732309 Pantodonts Paleocene mammals of South America Tiupampan Paleogene Bolivia Fossils of Bolivia Santa Lucía Formation Fossil taxa described in 1987 Prehistoric mammal genera