''Monotrematum sudamericanum'' is an extinct

monotreme Monotremes () are prototherian mammals of the order Monotremata. They are one of the three groups of living mammals, along with placentals ( Eutheria), and marsupials (Metatheria). Monotremes are typified by structural differences in their bra ...

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

from the Paleocene ( Peligran) Salamanca Formation in

Patagonia Patagonia () refers to a geographical region that encompasses the southern end of South America, governed by Argentina and Chile. The region comprises the southern section of the Andes Mountains with lakes, fjords, temperate rainforests, and ...

, Argentina. It is the only monotreme found outside

Oceania Oceania (, , ) is a region, geographical region that includes Australasia, Melanesia, Micronesia, and Polynesia. Spanning the Eastern Hemisphere, Eastern and Western Hemisphere, Western hemispheres, Oceania is estimated to have a land area of ...

Taxonomy

A species described in 1992 and assigned to a new genus ''Monotrematum'' as the type. It is currently the only known species of the genus. The authors compared their fossil material to the genus '' Obdurodon'', ornithorhynchid species first discovered at Australian fossil sites in 1975.

Description

''Monotrematum sudamericanum'' is known only from two lower and one upper

platypus The platypus (''Ornithorhynchus anatinus''), sometimes referred to as the duck-billed platypus, is a semiaquatic, egg-laying mammal endemic to eastern Australia, including Tasmania. The platypus is the sole living representative or monot ...

-like teeth. It is the only known non-

Australasia Australasia is a region that comprises Australia, New Zealand and some neighbouring islands in the Pacific Ocean. The term is used in a number of different contexts, including geopolitically, physiogeographically, philologically, and ecolo ...

n ornithorhynchid. The main difference, apart from continent and age, is its size: the teeth of ''Monotrematum'' are around twice as large as those of other similar species in the related genus '' Obdurodon''. The teeth of ''M. sudamericanum'' presently reside in the collections of Museo de La Plata and

Museo Paleontológico Egidio Feruglio The Museum of Paleontology Egidio Feruglio (MEF, in es, Museo Paleontológico Egidio Feruglio) is a science research and exhibition center in Trelew city, Patagonia, Argentina. Its permanent and travelling exhibitions focus on the fossil remain ...

, both in Argentina.R. Pascual, M. Archer, E. O. Jaureguizar, J. L. Prado, H. Godthelp and S. J. Hand. 1992. The first non-Australian monotreme: an early Paleocene South American platypus (Monotremata, Ornithorhynchidae). ''Platypus and Echidnas. Royal Zoological Society of New South Wales'' 1-14 According to Pascual, "The preserved enamel in the central region shows that the crown pattern is almost identical to that of ''Obdurodon'': it is composed of two V-shaped lobes, the anterior of which is wider, separated from the posterior one by a valley that connects the lingual and buccal sides of the crown separating the anterior and posterior lobes."

References

External links

* {{Taxonbar, from=Q782618 Ornithorhynchidae Prehistoric monotremes Paleocene mammals of South America Peligran Paleogene Argentina Fossils of Argentina Fossil taxa described in 1992 Taxa named by Rosendo Pascual Taxa named by Mike Archer (paleontologist) Taxa named by Edgardo Ortiz Jaureguizar Taxa named by Joyce Rodrigues do Prado Taxa named by Henk Godthelp Taxa named by Suzanne J. Hand Prehistoric mammal genera Golfo San Jorge Basin Salamanca Formation