Puijila

Last updated

Puijila
Temporal range: Late Oligocene - Early Miocene, 24–21  Ma
O
S
D
C
P
T
J
K
Pg
N
Puijila darwini (fossil).jpg
Restored skeleton
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Semantoridae
Genus: Puijila
Rybczynski et al., 2009
Species:
P. darwini
Binomial name
Puijila darwini
Rybczynski et al., 2009

Puijila darwini is an extinct species of stem-pinniped (seal) which lived during the Miocene about 21 to 24 million years ago. About a metre (3 feet) long, the animal had only minimal physical adaptations for swimming. Unlike modern pinnipeds, it did not have flippers and its shape was otter-like, albeit more specialized; its skull and teeth are the features that most clearly indicate that it is a seal. [1]

Contents

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 Charles Darwin. [2] The holotype and only known specimen is a nearly complete fossil skeleton. It is housed at the Canadian Museum of Nature, Ottawa, Ontario.

Background

Restoration Puijila BW.jpg
Restoration

Puijila darwini was a semi-aquatic carnivore which represents a morphological link in early pinniped evolution. Its fossil shows enlarged, probably webbed [3] 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 seals, bears and musteloids (weasels and otters). It had been popularly assumed that land mammals at some point transitioned to being more marine, 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 seal 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 that provides information about how the seals returned to the sea, similar to how Archaeopteryx illuminates the origin of birds.

Discovery

Life restoration of Puijila darwini Puijila.jpg
Life restoration of Puijila darwini

This novel species was discovered in 2007 by Natalia Rybczynski and her team using surface collection and screening at an early Miocene lake deposit of the Haughton Formation of Devon Island, Nunavut, Canada. [4] The paleobotanical record suggests that the paleoenvironment 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 is also an indication that the entire pinniped clade 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 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. [5]

Related Research Articles

<span class="mw-page-title-main">Carnivora</span> Order of mammals

Carnivora is an order of placental mammals that have specialized in primarily eating flesh, whose members are formally referred to as carnivorans. The order Carnivora is the sixth largest order of mammals, comprising at least 279 species on every major landmass and in a variety of habitats, ranging from the cold polar regions of Earth to the hyper-arid region of the Sahara Desert and the open seas. These mammals have a large array of diverse body plans with a wide diversity of shapes and sizes.

<span class="mw-page-title-main">Earless seal</span> Family of mammals

The earless seals, phocids, or true seals are one of the three main groups of mammals within the seal lineage, Pinnipedia. All true seals are members of the family Phocidae. They are sometimes called crawling seals to distinguish them from the fur seals and sea lions of the family Otariidae. Seals live in the oceans of both hemispheres and, with the exception of the more tropical monk seals, are mostly confined to polar, subpolar, and temperate climates. The Baikal seal is the only species of exclusively freshwater seal.

<span class="mw-page-title-main">Mustelidae</span> Family of mammals

The Mustelidae are a diverse family of carnivoran mammals, including weasels, badgers, otters, polecats, martens, grisons, and wolverines. Otherwise known as mustelids, they form the largest family in the suborder Caniformia of the order Carnivora with about 66 to 70 species in nine subfamilies.

<span class="mw-page-title-main">Otter</span> Subfamily of mammals (Lutrinae)

Otters are carnivorous mammals in the subfamily Lutrinae. The 13 extant otter species are all semiaquatic, aquatic, or marine. Lutrinae is a branch of the Mustelidae family, which includes weasels, badgers, mink, and wolverines, among other animals.

<span class="mw-page-title-main">Marine mammal</span> Mammals that rely on marine environments for feeding

Marine mammals are mammals that rely on marine (saltwater) ecosystems for their existence. They include animals such as cetaceans, pinnipeds, sirenians, sea otters and polar bears. They are an informal group, unified only by their reliance on marine environments for feeding and survival.

<span class="mw-page-title-main">Caniformia</span> Suborder of mammals

Caniformia is a suborder within the order Carnivora consisting of "dog-like" carnivorans. They include dogs, bears, raccoons, and mustelids. The Pinnipedia are also assigned to this group. The center of diversification for the Caniformia is North America and northern Eurasia. Caniformia stands in contrast to the other suborder of Carnivora, the Feliformia, the center of diversification of which was in Africa and southern Asia.

Potamotherium an extinct genus of caniform carnivoran from the Miocene epoch of France and Germany. It has historically been assigned to the family Mustelidae, but more recent studies suggest that it represents a primitive relative of pinnipeds

<i>Enaliarctos</i> Genus of pinniped

Enaliarctos is an extinct genus of pinnipedimorph, and may represent the ancestor to all pinnipeds. The five species in the genus Enaliarctos have been recovered from late Oligocene and early Miocene strata of California and Oregon.

<i>Desmatophoca</i> Extinct genus of carnivores

Desmatophoca is an extinct genus of early pinniped that lived during the Miocene, and is named from the Greek "phoca", meaning seal. A taxon of the family Desmatophocidae, it shares some morphological similarities with modern true seals. Two species are recognized: Desmatophoca oregonensis and Desmatophoca brachycephala. Little information exists regarding Desmatophoca, due to the small number of fossil samples obtained and identified.

<i>Imagotaria</i> Extinct genus of carnivores

Imagotaria is an extinct monotypic genus of walrus with the sole species Imagotaria downsi. Fossils of Imagotaria are known from the early late Miocene of California.

<span class="mw-page-title-main">Ursoidea</span> Superfamily of mammals

Ursoidea is a superfamily of arctoid carnivoran mammals that includes the families Subparictidae, Amphicynodontidae, and Ursidae. The last family includes the extant lineages of bears, as well as the extinct Hemicyoninae and Ursavinae.

<i>Kolponomos</i> Extinct genus of mammals

Kolponomos is an extinct genus of carnivoran mammal that existed in the Late Arikareean North American Land Mammal Age, early Miocene epoch, about 20 million years ago. It was likely a marine mammal. The genus was erected in 1960 by Ruben A. Stirton, a paleontologist at the University of California Museum of Paleontology, Berkeley, for the species K. clallamensis, on the basis of a partial skull and jaw found on the Olympic Peninsula. At the time, Stirton questionably assigned it to Procyonidae, its systematic position remained problematic until the discovery of more fossils including a nearly complete cranium from the original locality of K. clallamensis which helped identify it as part of the group from which pinnipeds evolved.

<i>Pelagiarctos</i> Extinct genus of carnivores

Pelagiarctos was a genus of walrus that lived during the Mid Miocene, approx. 13-15 mya. Its remains have been found in the Sharktooth Hill Bonebed, in Kern County, California. It was originally described as an Otariidae, though it is now usually considered to be a basal Odobenidae.

Natalia Rybczynski is a Canadian paleobiologist, professor and researcher.

<i>Pontolis</i> Extinct genus of carnivores

Pontolis is an extinct genus of large walrus. It contained three species, P. magnus, P. barroni, and P. kohnoi. Like all pinnipeds, Pontolis was a heavily built amphibious carnivore. Pontolis lived along the Pacific coast of North America along what is now the western coasts of California and Oregon between 11.608 and 5.332 million years ago, during the Miocene and Pliocene.

<span class="mw-page-title-main">Amphicynodontidae</span> Extinct clade of mammals

Amphicynodontidae is a probable clade of extinct arctoids. While some researchers consider this group to be an extinct subfamily of bears, a variety of morphological evidence links amphicynodontines with pinnipeds, as the group were semi-aquatic otter-like mammals. In addition to the support of the pinniped–amphicynodontine clade, other morphological and some molecular analyses support bears being the closest living relatives to pinnipeds. According to McKenna and Bell (1997) Amphicynodontinae are classified as stem-pinnipeds in the superfamily Phocoidea. Fossils of these mammals have been found in Europe, North America and Asia. Amphicynodontines should not be confused with Amphicyonids (bear-dogs), a separate family of Carnivora which is a sister clade to arctoids within the caniforms, but which may be listed as a clade of extinct arctoids in older publications.

<span class="mw-page-title-main">Teratodontidae</span> Extinct clade of mammals

Teratodontinae is a subfamily of extinct hyaenodonts. Fossil remains of these mammals are known from Middle Eocene to Late Miocene deposits in Africa, the Arabian Peninsula, and Asia.

<span class="mw-page-title-main">Semantoridae</span> Extinct family of mammals

Semantoridae is an extinct family of stem-pinnipeds with fossils found in France, Kazakhstan, and Canada, dating back to various points in time in the Miocene epoch. Based on their overall anatomy semantorids were not marine specialists, as their elongated bodies, a long tail and robust limbs suggest they were freshwater animals not unlike otters. Indeed, at least some taxa such as Semantor and Potamotherium were initially classified as mustelids closely related to otters.

Subparictidae is an extinct family of early Paleogene arctoid carnivorans endemic to North America that closely related to bears. They were small, raccoon-like mammals that lived from the Eocene to the early Miocene. This family includes a handful of genera such as Subparictis, Parictis, Nothocyon, and Eoarctos.

References

  1. 1 2 Ed Yong (2009-04-22). "Puijila, the walking seal – a beautiful transitional fossil". Not Exactly Rocket Science. Discover Magazine. Archived from the original on 3 November 2012. Retrieved 2014-10-07.
  2. "Puijila: A prehistoric walking seal". Puijila: A prehistoric walking seal. Canadian Museum of Nature. Archived from the original on 2015-06-21. Retrieved 2014-10-07.
  3. "'Missing link' fossil seal walked" (Press release). BBC News. 2009-04-22. Archived from the original on 2 August 2014. Retrieved 2014-10-07.
  4. Rybczynski, Natalia; Dawson, Mary R.; Tedford, Richard H. (2009). "A semi-aquatic Arctic mammalian carnivore from the Miocene epoch and origin of Pinnipedia". Nature. 458 (7241): 1021–1024. Bibcode:2009Natur.458.1021R. doi:10.1038/nature07985. ISSN   0028-0836. PMID   19396145. S2CID   4371413.
  5. Yong, Ed (22 April 2009). "Puijila, the walking seal – a beautiful transitional fossil". National Geographic. Retrieved 10 January 2024.