''Puijila darwini'' is an extinct

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 ...

of stem-

pinniped Pinnipeds (pronounced ), commonly known as seals, are a widely range (biology), distributed and diverse clade of carnivorous, fin-footed, semiaquatic, mostly marine mammal, marine mammals. They comprise the extant taxon, extant family (biology ...

which lived during the

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

epoch about 21 to 24 million years ago. Approximately a metre (three feet) 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. It is considered to be the most primitive pinnipedimorph yet found. The genus name is an Inuktitut word for a young seal; the species name honours the English naturalist

Charles Darwin Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended ...

. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ...

and only known specimen is a nearly complete fossilised skeleton. It is being housed at the Canadian Museum of Nature in Ottawa,

Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central C ...

Background

''Puijila darwini'' was a semi-aquatic

carnivore A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other s ...

which represents a morphological link in early

evolution. Its fossil remains demonstrate the presence of enlarged, probably webbed feet, robust forelimbs and an unspecialized tail. 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 to morphologically precede the more familiarly structured genus '' Enaliarctos'', despite apparently being a younger genus. In other words, ''Puijila'' is a

transitional fossil A transitional fossil is any fossilized remains of a life form that exhibits traits common to both an ancestral group and its derived descendant group. This is especially important where the descendant group is sharply differentiated by gross a ...

that provides information about how the seal family returned to the seas, similar to the way that '' Archaeopteryx'' illuminates the origin of modern birds.

Discovery

This novel species was discovered in 2007 by

Natalia Rybczynski Natalia Rybczynski is a Canadian paleobiologist, professor and researcher. She is a research scientist with the Canadian Museum of Nature and holds a professorship at Carleton University in Ottawa, Ontario. Her doctorate was obtained at Duke Uni ...

and her team using surface collection and screening at an early Miocene lake deposit of the Haughton Formation of Devon Island in Nunavut,

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

. 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 an indication that the entire pinniped family may have originated in the

Arctic The Arctic ( or ) is a polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Canada (Yukon, Northwest Territories, Nunavut), Danish Realm (Greenland), Finland, Iceland, N ...

. 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.

References

External links

Natalia Rybczynski at the Canadian Museum of Nature
* Brian Switek
''Puijila darwini'': A Significant Seal
* Robert Boessenecker

* Ed Yong
''Puijila'', the walking seal — a beautiful transitional fossil

by Bob Holmes,

New Scientist ''New Scientist'' is a magazine covering all aspects of science and technology. Based in London, it publishes weekly English-language editions in the United Kingdom, the United States and Australia. An editorially separate organisation publish ...

, 25 April 2009, p. 10. {{Taxonbar, from=Q895480 Prehistoric pinnipeds of North America Prehistoric mammals of North America Aquitanian genus extinctions Miocene pinnipeds Transitional fossils Fossil taxa described in 2009 Chattian genus first appearances Prehistoric carnivoran genera