''Monotrematum sudamericanum'' is an extinct monotreme

species In biology, a species is the basic unit of 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 the appropriate s ...

from the Paleocene (

Peligran The Peligran ( es, Peligrense) age is a period of geologic time (62.5–59.0 Ma) within the Paleocene epoch of the Paleogene, used more specifically with South American land mammal ages (SALMA). It follows the Tiupampan and precedes the Riochican ...

)

Salamanca Formation The Salamanca Formation is a geologic formation in the Golfo San Jorge Basin of central Patagonia that yields well-preserved, well-dated fossils from the early Paleocene. Studies of these fossils are providing new data on plant and animal diversit ...

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 g ...

, Argentina. It is the only monotreme found outside

Oceania Oceania (, , ) is a geographical region that includes Australasia, Melanesia, Micronesia, and Polynesia. Spanning the Eastern and Western hemispheres, Oceania is estimated to have a land area of and a population of around 44.5 million ...

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 ''Obdurodon'' is a genus of extinct platypus-like Australian monotreme which lived from the Late Oligocene to the Late Miocene. Three species have been described in the genus, the type species ''Obdurodon insignis'', plus ''Obdurodon dicksoni'' ...

'',

ornithorhynchid The Ornithorhynchidae are one of the two extant families in the order Monotremata, and contain the platypus and its extinct relatives. The other family is the Tachyglossidae, or echidnas. Within the Ornithorhynchidae are the genera '' Monotrem ...

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 mono ...

-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 ecologi ...

. 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 ''

''. The teeth of ''M. sudamericanum'' presently reside in the collections of Museo de La Plata and Museo Paleontológico Egidio Feruglio, 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