Maddenia (mammal)

Maddenia is an extinct genus of astrapothere, meridiungulate herbivore mammals characterised by its large tusks and the development of proboscis, endemic of South America. This genus was discovered in an outcrop near to the Lake Colhué Huapi in the place La Cantera, in the Chubut Province, in Argentina, in sediments corresponding to the Sarmiento Formation, that dates of the Late Oligocene (Deseadan South American land mammal age).[1][2]

Maddenia
Temporal range: Late Oligocene (Deseadan)
~29–21 Ma
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: †Astrapotheria
Family: †Astrapotheriidae
Genus: †Maddenia
Kramarz & Bond, 2009
Type species
Maddenia lapidaria
Kramarz & Bond, 2009

Etymology

The name of the genus Maddenia, is in homage to the palaeontologist Richard Madden, by his contributions to the palaeontology of South America, whereas the name of the type species and only known, Maddenia lapidaria, derives of the Latin lapidarius, "of stone".[2]

Description

This species is based in the holotype MPEF PV 7735, a fragment of jawbone with molar and premolar teeth associated and a partial canine associated, in addition to several additional specimens that include isolated teeth and other fragments of jaws. From these remains it was established that Maddenia was a small astrapothere, near of 50% smaller than Astraponotus. Its molar were high, with complex crowns and with canines moderately developed, characteristics of the advanced astrapotheres of big size of the Oligocene and the Miocene (like Astrapotherium and Granastrapotherium), which suggests that it must to occupy a habitat differentiated regarding other forms of big size, and that by its anatomical characteristics constitutes an intermediate form between the primitive forms like Albertogaudrya and the astrapotherids like Parastrapotherium, with which conform sister taxa to the two subfamilies of the family Astrapotheriidae, Astrapotheriinae and Uruguaytheriinae.[2]

Phylogeny

Cladogram according to Bond et al., 2011, standing out the phylogenetic position of Maddenia:[3]

Astrapotheria
 

Eoastrapostylops

 
 
 

Trigonostylops

 
 
 

Tetragonostylops

 
 
 

Antarctodon

 
 
 

Albertogaudrya

 
 
 

Scaglia

 
Astrapotheriidae
 

Astraponotus

 
 
 

Maddenia

 
 
 

Parastrapotherium

 
 
 

Astrapotherium

 
 

Granastrapotherium

 
 
 
 
 
 
 
 
 
 
 

References
  1. Maddenia at Fossilworks.org
  2. Alejandro G. Kramarz and Mariano Bond (2009) A new oligocene astrapothere (Mammalia, Meridiungulata) from Patagonia and a new appraisal of astrapothere phylogeny. Journal of Systematic Palaeontology, 7 : pp 117-128
  3. Bond, Mariano; Kramarz, Alejandro; MacPhee, Ross D. E.; Reguero, Marcelo (2011). "A new astrapothere (Mammalia, Meridiungulata) from La Meseta Formation, Seymour (Marambio) Island, and a reassessment of previous records of Antarctic astrapotheres" (PDF). American Museum Novitates. 3718: 16. doi:10.1206/3718.2.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.