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Puijila

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Puijila darwini
Fossil range: Late Oligocene-Early Miocene
Puijila BW
Scientific classification

Class

Mammalia

Order

Carnivora

Suborder

Pinnipedia

Family

Puijilae

Genus

Puijila Rybczynski, 2009

Species



Puijila is a genus of extinct pinniped that lived about 21 to 24 million years ago. Approximately a meter (3'4'') in length, the animal possessed only minimal physical adaptations for swimming. Unlike modern pinnipeds, it did not have flippers and its overall form was otter-like, albeit more specialized; its skull and teeth are the features that most clearly indicate that it is a seal.[1] It is considered to be the most primitive member of the seal family yet found. It is named in honour of the English naturalist Charles Darwin.[2] The one known specimen is a nearly complete fossilized skeleton. It is being housed at the Canadian Museum of Nature in Ottawa, Ontario.

DescriptionEdit

Puijila darwini was a semi-aquatic carnivore which represents a morphological link in early pinniped evolution. Its fossil remains demonstrate the presence of enlarged, probably webbed feet, robust forelimbs and an unspecialized tail.[3] This suggests that Puijila swam quadrupedally using its webbed fore and hind feet for propulsion. Phylogenetic studies including molecular evidence suggest a sister relationship between pinnipeds (seals) and ursoids (bears) as well as musteloids (weasels and otters). It had been popularly assumed that land-dwelling mammals had at some point transitioned to a more marine existence, in essence "returning to the sea" in order to gain some sort of survival advantage. However, fossil evidence of this transition had been weak or contentious. The discovery of Puijila is important as it represents a morphological link in early pinniped evolution, and one that appears, morphologically, to precede the more familiarly structured Enaliarctos genus, despite apparently being a younger genus. In other words, Puijila is a transitional fossil that provides information about how the seal family returned to the seas, similar to the way that Archaeopteryx illuminates the origin of modern birds.

DiscoveryEdit

Puijila
Life restoration of Puijila darwini.
Meghunter99Added by Meghunter99
Puijila fossil
Puijila darwini is seen at the Canadian Museum of Nature
Meghunter99Added by Meghunter99

This novel species was discovered in 2007 and described in 2009 by Dr. Natalia Rybczynski and her team using surface collection and screening at an Early Miocene lake deposit of the Haughton Formation of Devon Island in Nunavut, Canada. [4] The palaeobotanical record suggests that the palaeoenvironment around the lake comprised a forest community transitional between a boreal and a conifer–hardwood forest, in a cool temperate, coastal climate with moderate winters. Puijila darwini is the first mammalian carnivore found in the Haughton lake deposits. This also gives a good indication that the entire pinniped family may have originated in the Arctic.[1]

The initial find is credited to field assistant Elizabeth Ross, and was partly a matter of luck. Ross had been unexpectedly stranded with the team's ATV which had run out of fuel several kilometers away from base camp. The brain case was discovered a year later on the first day of the 2008 field expedition by Martin Lipman, the team's photographer.

ReferencesEdit

  1. ^ a b Ed Yong (2009-04-22). "Puijila, the walking seal - a beautiful transitional fossil". ScienceBlogs.com. http://scienceblogs.com/notrocketscience/2009/04/puijila_the_walking_seal_beautiful_transitional_fossil.php. Retrieved on 2009-04-24. 
  2. ^ "'Missing link' fossil seal walked". BBC News. 2009-04-22. http://news.bbc.co.uk/2/hi/science/nature/8012322.stm. Retrieved on 2009-04-24. 
  3. ^ Richard Black. "'Missing link' fossil seal walked". BBC News. Archived from the original on 30 April 2009. http://www.webcitation.org/5gR55QHoB. 
  4. ^ Rybczynski, N. (2009). "A semi-aquatic Arctic mammalian carnivore from the Miocene epoch and origin of Pinnipedia". Nature 458 (7241): 1021–1024. doi:10.1038/nature07985. 


External linksEdit

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