''Puijila darwini'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

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 distributed and diverse clade of carnivorous, fin-footed, semiaquatic, mostly marine mammals. They comprise the extant families Odobenidae (whose only living member is the walru ...

which lived during the

Miocene The Miocene ( ) is the first 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 means "less recen ...

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 Otters are carnivorous mammals in the subfamily Lutrinae. The 13 extant otter species are all semiaquatic, aquatic, or marine, with diets based on fish and invertebrates. Lutrinae is a branch of the Mustelidae family, which also includes wea ...

-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 Inuktitut (; , syllabics ; from , "person" + , "like", "in the manner of"), also Eastern Canadian Inuktitut, is one of the principal Inuit languages of Canada. It is spoken in all areas north of the tree line, including parts of the provinces o ...

word for a young seal; the species name honours the

English English usually refers to: * English language * English people English may also refer to: Peoples, culture, and language * ''English'', an adjective for something of, from, or related to England ** English national ide ...

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 fr ...

. 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 several ...

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

Ottawa Ottawa (, ; Canadian French: ) is the capital city of Canada. It is located at the confluence of the Ottawa River and the Rideau River in the southern portion of the province of Ontario. Ottawa borders Gatineau, Quebec, and forms the core ...

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 Ca ...

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 sof ...

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 ''Enaliarctos''From Greek , ''enalios'', of the sea; and , ''arktos'', bear, "referring to the arctoid, including ursid, Carnivora" (Mitchell & Tedford, 1973, p. 218). is an extinct genus of pinnipedimorph, and may represent the ancestor to all ...

'', 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 ''Archaeopteryx'' (; ), sometimes referred to by its German name, "" ( ''Primeval Bird''), is a genus of bird-like dinosaurs. The name derives from the ancient Greek (''archaīos''), meaning "ancient", and (''ptéryx''), meaning "feather" ...

'' 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 Devon Island ( iu, ᑕᓪᓗᕈᑎᑦ, ) is an island in Canada and the largest uninhabited island (no permanent residents) in the world. It is located in Baffin Bay, Qikiqtaaluk Region, Nunavut, Canada. It is one of the largest members of the Ar ...

Nunavut Nunavut ( , ; iu, ᓄᓇᕗᑦ , ; ) is the largest and northernmost Provinces and territories of Canada#Territories, territory of Canada. It was separated officially from the Northwest Territories on April 1, 1999, via the ''Nunavut Act'' ...

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 regions of Earth, 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 (Greenla ...

. 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 publishe ...

, 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