Multituberculate

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Multituberculates
Temporal range: JurassicOligocene
160 to 35 million years ago
Skull of Ptilodus
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Subclass: Allotheria
Order: †Multituberculata
Cope, 1884
Suborders

The Multituberculates were a group of rodent-like mammals which survived for about 120 million years – the longest fossil history of any mammal lineage.

They were eventually outcompeted by rodents, becoming extinct during the early Oligocene.[1]

At least 200 species are known, ranging from mouse-sized to beaver-sized. These species occupied many ecological niches, ranging from burrow-dwelling to squirrel-like tree-dwelling.[2]

Multituberculates are usually placed outside both the two main groups of living mammals, the Theria (placentals and marsupials), and monotremes. Some cladistic analyses put them closer to Theria than to monotremes.[3][4]

Biology[change | change source]

The multituberculates had a head anatomy similar to rodents. They had cheek-teeth separated from the chisel-like front teeth by a wide tooth-less gap (called the diastema). Each cheek-tooth displayed several rows of small cusps (or tubercles, hence the name) which worked against similar rows in the teeth of the jaw. It was an efficient chopping device.

Most small multituberculates would have eaten seeds and nuts, supplemented with insects, worms, and fruit.

The structure of the pelvis in the Multituberculata suggests that they gave birth to tiny helpless young, similar to modern marsupials.[2][5]

References[change | change source]

  1. Krause, David W. 1986. Competitive exclusion and taxonomic displacement in the fossil record: the case of rodents and multituberculates in North America. Contributions to Geology (Special Paper 3): 95–117.
  2. 2.0 2.1 Weil, Anne (1997). "Introduction to Multituberculates: the “lost tribe” of mammals". Berkeley: University of California Museum of Paleontology. http://www.ucmp.berkeley.edu/mammal/multis/multis.html. Retrieved January 2010.
  3. Benton, Michael J. 2004. Vertebrate palaeontology. p. 300
  4. Carrano, Matthew T. et al 2006. Amniote paleobiology: perspectives on the evolution of mammals, birds, and reptiles. University of Chicago Press. p358. IBSN 0-226-09478-2
  5. Kielan-Jaworowska, Zofia, Richard L. Cifelli, and Zhe-Xi Luo 2005. Mammals from the Age of Dinosaurs: origins, evolution, and structure. p. 299