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  • the discovery of Icadyptes salasi, a prehistoric five-foot-tall penguin in Peru, has caused scientists to reconsider the timeline of penguin evolution?
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From Wikipedia, the free encyclopedia

Penguins
Fossil range: Paleocene-Recent, 62–0 Ma
Gentoo Penguin, Pygoscelis papua
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Infraclass: Neognathae
Order: Sphenisciformes
Sharpe, 1891
Family: Spheniscidae
Bonaparte, 1831
Modern genera

Aptenodytes
Eudyptes
Eudyptula
Megadyptes
Pygoscelis
Spheniscus
For prehistoric genera, see Systematics

Penguins (order Sphenisciformes, family Spheniscidae) are a group of aquatic, flightless birds living almost exclusively in the southern hemisphere, especially in Antarctica. Highly adapted for life in the water, penguins have countershaded dark and white plumage, and their wings have become flippers. Most penguins feed on krill, fish, squid, and other forms of sealife caught while swimming underwater. They spend about half of their life on land and half in the oceans.

Although all penguin species are native to the southern hemisphere, they are not found only in cold climates, such as Antarctica. In fact, only a few species of penguin live so far south. Several species are found in the temperate zone, and one species, the Galápagos Penguin, lives near the equator.

The largest living species is the Emperor Penguin (Aptenodytes forsteri): adults average about 1.1 m (3 ft 7 in) tall and weigh 35 kg (75 lb) or more. The smallest penguin species is the Little Blue Penguin (Eudyptula minor), also known as the Fairy Penguin, which stands around 40 cm tall (16 in) and weighs 1 kg (2.2 lb). Among extant penguins, larger penguins inhabit colder regions, while smaller penguins are generally found in temperate or even tropical climates (see also Bergmann's Rule). Some prehistoric species attained enormous sizes, becoming as tall or as heavy as an adult human (see below for more). These were not restricted to Antarctic regions; on the contrary, subantarctic regions harboured high diversity, and at least one giant penguin occurred in a region not quite 2,000 km south of the equator 35 mya, in a climate decidedly warmer than today.

Contents

Etymology

The etymology of the word "penguin" is highly disputed. The English word is not apparently of French[1], nor of Breton[2] or Spanish[3] origin (both attributed to the French word pingouin "auk"), but first appears in English or Dutch.[1]

Some dictionaries suggest a derivation from Welsh pen "head" and gwyn "white", including the Oxford English Dictionary[4], the American Heritage Dictionary[5], the Century Dictionary[6] and Merriam-Webster[7], on the basis that the name was originally applied to the great auk, which had white spots in front of its eyes (although its head was black).

An alternative etymology, found in a few English dictionaries, links the word to Latin pinguis "fat", from its perceived appearance. This etymology would be improbable if "penguin" were found to have been originally applied to the great auk, as some sources suggest.[4][6][2]

A third theory states that the word is an alteration of “pen-wing”, with reference to the rudimentary wings of both great auks and penguins. This has been criticised for the unexplained nature of the alteration of the word.[6]

Systematics and evolution

Living species and recent extinctions

Emperor Penguins (Aptenodytes forsteri), the largest living species.
Adelie Penguin (Pygoscelis adeliae) feeding young. Like its relatives, a neatly bi-coloured species with a head marking.
Magellanic Penguins (Spheniscus magellanicus) guarding nest burrow. The closed neck collar denotes this species.
Closeup of Southern Rockhopper Penguin (Eudyptes chrysocome).

The number of extant penguin species is debated. Depending on which authority is followed, penguin biodiversity varies between 17 and 20 living species, all in the subfamily Spheniscinae. Some sources consider the White-flippered Penguin a separate Eudyptula species, while others treat it as a subspecies of the Little Penguin;[8][9] the actual situation seems to be more complicated.[10] Similarly, it is still unclear whether the Royal Penguin is merely a color morph of the Macaroni penguin. The status of the Rockhopper penguins is also unclear.

Updated after Marples (1962), Acosta Hospitaleche (2004), and Ksepka et al. (2006).

Subfamily Spheniscinae – Modern penguins

Fossil genera

Order Sphenisciformes

  • Basal and unresolved taxa (all fossil)
    • Waimanu – basal (Middle-Late Paleocene)
    • Perudyptes (Middle Eocene of Atacama Desert, Peru) – basal?
    • Spheniscidae gen. et sp. indet. CADIC P 21 (Leticia Middle Eocene of Punta Torcida, Argentina)[11]
    • Delphinornis (Middle/Late Eocene? – Early Oligocene of Seymour Island, Antarctica) – Palaeeudyptinae, basal, new subfamily 1?
    • Archaeospheniscus (Middle/Late Eocene – Late Oligocene) – Palaeeudyptinae? New subfamily 2?
    • Marambiornis (Late Eocene –? Early Oligocene of Seymour Island, Antarctica) – Palaeeudyptinae, basal, new subfamily 1?
    • Mesetaornis (Late Eocene –? Early Oligocene of Seymour Island, Antarctica) – Palaeeudyptinae, basal, new subfamily 1?
    • Tonniornis (Late Eocene –? Early Oligocene of Seymour Island, Antarctica)
    • Wimanornis (Late Eocene –? Early Oligocene of Seymour Island, Antarctica)
    • Duntroonornis (Late Oligocene of Otago, New Zealand) – possibly Spheniscinae
    • Korora (Late Oligocene of S Canterbury, New Zealand)
    • Platydyptes (Late Oligocene of New Zealand) – possibly not monophyletic; Palaeeudyptinae, Paraptenodytinae or new subfamily?
    • Spheniscidae gen. et sp. indet. (Late Oligocene/Early Miocene of Hakataramea, New Zealand)
    • Madrynornis (Puerto Madryn Late Miocene of Argentina) – possibly Spheniscinae
    • Pseudaptenodytes (Late Miocene/Early Pliocene)
    • Dege (Early Pliocene of South Africa) – possibly Spheniscinae
    • Marplesornis (Early Pliocene) – possibly Spheniscinae
    • Nucleornis (Early Pliocene of Duinfontain, South Africa) – possibly Spheniscinae
    • Inguza (Late Pliocene) – probably Spheniscinae; formerly Spheniscus predemersus
A damaged tarsometatarsus of the prehistoric Narrow-flippered Penguin (Palaeeudyptes antarcticus).
  • Family Spheniscidae
    • Subfamily Palaeeudyptinae – Giant penguins (fossil)
      • Crossvallia (Cross Valley Late Paleocene of Seymour Island, Antarctica) – tentatively assigned to this subfamily
      • Anthropornis (Middle Eocene? – Early Oligocene of Seymour Island, Antarctica) – tentatively assigned to this subfamily
      • Icadyptes (Late Eocene of Atacama Desert, Peru)
      • Palaeeudyptes (Middle/Late Eocene – Late Oligocene) – polyphyletic; some belong in other subfamilies
      • Pachydyptes (Late Eocene)
      • Anthropodyptes (Middle Miocene) – tentatively assigned to this subfamily
    • Subfamily Paraptenodytinae – Stout-footed penguins (fossil)
      • Arthrodytes (San Julian Late Eocene/Early Oligocene – Patagonia Early Miocene of Patagonia, Argentina)
      • Paraptenodytes (Early – Late Miocene/Early Pliocene)
    • Subfamily Palaeospheniscinae – Slender-footed penguins (fossil)
      • Eretiscus (Patagonia Early Miocene of Patagonia, Argentina)
      • Palaeospheniscus (Early? – Late Miocene/Early Pliocene) – includes Chubutodyptes

Taxonomy

Some recent sources[12] apply the phylogenetic taxon Spheniscidae to what here is referred to as Spheniscinae. Furthermore, they restrict the phylogenetic taxon Sphenisciformes to flightless taxa, and establish the phylogenetic taxon Pansphenisciformes as equivalent to the Linnean taxon Sphenisciformes,[13] i.e., including any flying basal "proto-penguins" to be discovered eventually. Given that neither the relationships of the penguin subfamilies to each other nor the placement of the penguins in the avian phylogeny is presently resolved, this seems spurious and in any case is confusing; the established Linnean system is thus followed here.

Evolution

The evolutionary history of penguins is well-researched and represents a showcase of evolutionary biogeography; though as penguin bones of any one species vary much in size and few good specimens are known, the alpha taxonomy of many prehistoric forms still leaves much to be desired. Some seminal articles about penguin prehistory have been published since 2005,[14][15][16][17] the evolution of the living genera can be considered resolved by now.

The basal penguins lived around the time of the Cretaceous–Tertiary extinction event somewhere in the general area of (southern) New Zealand and Byrd Land, Antarctica.[16] Due to plate tectonics, these areas were at that time less than 1,500 kilometers (932 mi) apart rather than the 4,000 kilometers (2,485 mi) of today. The most recent common ancestor of penguins and their sister clade can be roughly dated to the CampanianMaastrichtian boundary, around 70–68 mya.[15][17][18] What can be said as certainly as possible in the absence of direct (i.e., fossil) evidence is that by the end of the Cretaceous, the penguin lineage must have been evolutionarily well distinct, though much less so morphologically; it is fairly likely that they were not yet entirely flightless at that time, as flightless birds have generally low resilience to the breakdown of trophic webs that follows the initial phase of mass extinctions because of their below-average dispersal capabilities (see also Flightless Cormorant).[citation needed]

The basal fossils

The oldest known fossil penguin species is Waimanu manneringi, which lived in the early Paleocene epoch of New Zealand, or about 62 mya.[17] While they were not as well-adapted to aquatic life as modern penguins, Waimanu were generally loon-like birds but already flightless, with short wings adapted for deep diving.[citation needed] They swam on the surface using mainly their feet, but the wings were – as opposed to most other diving birds, living and extinct – already adapting to underwater locomotion.[citation needed]

Perudyptes from northern Peru was dated to 42 mya. An unnamed fossil from Argentina proves that by the Bartonian (Middle Eocene), some 39–38 mya,[19] primitive penguins had spread to South America and were in the process of expanding into Atlantic waters.[13]

Palaeeudyptines

During the Late Eocene and the Early Oligocene (40–30 mya), some lineages of gigantic penguins existed. Nordenskjoeld's Giant Penguin was the tallest, growing nearly 1.80 meters (6 ft) tall. The New Zealand Giant Penguin was probably the heaviest, weighing 80 kg or more. Both were found on New Zealand, the former also in the Antarctic farther eastwards.

Traditionally, most extinct species of penguins, giant or small, had been placed in the paraphyletic subfamily called Palaeeudyptinae. More recently, with new taxa being discovered and placed in the phylogeny if possible, it is becoming accepted that there were at least two major extinct lineages. One or two closely related ones occurred in Patagonia, and at least one other—which is or includes the paleeudyptines as recognized today – occurred on most Antarctic and subantarctic coasts.

But size plasticity seems to have been great at this initial stage of penguin radiation: on Seymour Island, Antarctica, for example, around 10 known species of penguins ranging in size from medium to huge apparently coexisted some 35 mya during the Priabonian (Late Eocene).[20] It is not even known whether the gigantic palaeeudyptines constitute a monophyletic lineage, or whether gigantism was evolved independently in a much restricted Palaeeudyptinae and the Anthropornithinae – whether they were considered valid, or whether there was a wide size range present in the Palaeeudyptinae as delimited as usually done these days (i.e., including Anthropornis nordenskjoeldi).[16] The oldest well-described giant penguin, the 5-foot-tall Icadyptes salasi, actually occurred as far north as northern Peru about 36 mya.

In any case, the gigantic penguins had disappeared by the end of the Paleogene, around 25 mya. Their decline and disappearance coincided with the spread of the Squalodontoidea and other primitive, fish-eating toothed whales, which certainly competed with them for food, and were ultimately more successful.[15] A new lineage, the Paraptenodytes, which includes smaller but decidedly stout-legged forms, had already arisen in southernmost South America by that time. The early Neogene saw the emergence of yet another morphotype in the same area, the similarly-sized but more gracile Palaeospheniscinae, as well as the radiation that gave rise to the penguin biodiversity of our time.

Origin and systematics of modern penguins

Modern penguins consititute two undisputed clades and another two more basal genera with more ambiguous relationships.[14] The origin of the Spheniscinae lies probably in the latest Paleogene, and geographically it must have been much the same as the general area in which the order evolved: the oceans between the Australia-New Zealand region and the Antarctic.[15] Presumedly diverging from other penguins around 40 mya,[15] it seems that the Spheniscinae were for quite some time limited to their ancestral area, as the well-researched deposits of the Antarctic Peninsula and Patagonia have not yielded Paleogene fossils of the subfamily. Also, the earliest spheniscine lineages are those with the most southern distribution.

The genus Aptenodytes appears to be the basalmost divergence among living penguins [21] [22] they have bright yellow-orange neck, breast, and bill patches; incubate by placing their eggs on their feet, and when they hatch the chicks are almost naked. This genus has a distribution centered on the Antarctic coasts and barely extends to some subantarctic islands today.

Pygoscelis contains species with a fairly simple black-and-white head pattern; their distribution is intermediate, centered on Antarctic coasts but extending somewhat northwards from there. In external morphology, these apparently still resemble the common ancestor of the Spheniscinae, as Aptenodytes' autapomorphies are in most cases fairly pronounced adaptations related to that genus' extreme habitat conditions. As the former genus, Pygoscelis seems to have diverged during the Bartonian,[23] but the range expansion and radiation that led to the present-day diversity probably did not occur until much later; around the Burdigalian stage of the Early Miocene, roughly 20–15 mya.[15]

The genera Spheniscus and Eudyptula contain species with a mostly subantarctic distribution centered on South America; some, however, range quite far northwards. They all lack carotenoid coloration, and the former genus has a conspicuous banded head pattern; they are unique among living penguins by nesting in burrows. This group probably radiated eastwards with the Antarctic Circumpolar Current out of the ancestral range of modern penguins throughout the Chattian (Late Oligocene), starting approximately 28 mya.[15] While the two genera separated during this time, the present-day diversity is the result of a Pliocene radiation, taking place some 4–2 mya.[15]

The MegadyptesEudyptes clade occurs at similar latitudes (though not as far north as the Galapagos Penguin), has its highest diversity in the New Zealand region, and represent a westward dispersal. They are characterized by hairy yellow ornamental head feathers; their bills are at least partly red. These two genera diverged apparently in the Middle Miocene (Langhian, roughly 15–14 mya), but again, the living species of Eudyptes are the product of a later radiation, stretching from about the late Tortonian (Late Miocene, 8 mya) to the end of the Pliocene.[15]

The geographical and temporal pattern or spheniscine evolution corresponds closely to two episodes of global cooling documented in the paleoclimatic record.[15] The emergence of the subantarctic lineage at the end of the Bartonian corresponds with the onset of the slow period of cooling that eventually led to the ice ages some 35 million years later. With habitat on the Antarctic coasts declining, by the Priabonian more hospitable conditions for most penguins existed in the subantarctic regions rather than in Antarctica itself[24]. Notably, the cold Antarctic Circumpolar Current also started as a continuous circumpolar flow only around 30 mya, on the one hand forcing the Antarctic cooling, and on the other facilitating the eastward expansion of Spheniscus to South America and eventually beyond.[15] Despite this, there is no fossil evidence to support the idea a crown radiation from the antarctic continent in the Paleogene [25].

Later, an interspersed period of slight warming was ended by the Middle Miocene Climate Transition, a sharp drop in global average temperature from 14–12 mya, and similar abrupt cooling events followed at 8 mya and 4 mya; by the end of the Tortonian, the Antarctic ice sheet was already much like today in volume and extent. The emergence of most of today's subantarctic penguin species almost certainly was caused by this sequence of Neogene climate shifts.

Relationship to other bird orders

Penguin ancestry beyond Waimanu remains unknown and not well-resolved by molecular or morphological analyses. The latter tend to be confounded by the strong adaptive autapomorphies of the Sphenisciformes; a sometimes perceived fairly close relationship between penguins and grebes is almost certainly an error based on both groups' strong diving adaptations, which are homoplasies. On the other hand, different DNA sequence datasets do not agree in detail with each other either.

Humboldt Penguins in an aquarium. The penguin is an accomplished swimmer, having flippers instead of wings.

What seems clear is that penguins belong to a clade of Neoaves (living birds except paleognaths and fowl) that comprises what is sometimes called "higher waterbirds" to distinguish them from the more ancient waterfowl. This group contains such birds as storks, rails, and the seabirds, with the possible exception of the Charadriiformes.[26]

Inside this group, penguin relationships are far less clear. Depending on the analysis and dataset, a close relationship to Ciconiiformes[17] or to Procellariiformes[15] has been suggested. Some think the penguin-like plotopterids (usually considered relatives of anhingas and cormorants) may actually be a sister group of the penguins, and that penguins may have ultimately shared a common ancestor with the Pelecaniformes and consequently would have to be included in that order, or that the plotopterids were not as close to other pelecaniforms as generally assumed, which would necessitate splitting the traditional Pelecaniformes in three.[27]

Anatomy and physiology

Orcas swim by an iceberg with Adelie Penguins in the Ross Sea, Antarctica. The Drygalski ice tongue is visible in the background.

Penguins are superbly adapted to an aquatic life. Their vestigial wings have become flippers, useless for flight in the air. In the water, however, penguins are astonishingly agile. Within the smooth plumage a layer of air is preserved, ensuring buoyancy. The air layer also helps insulate the birds in cold waters. On land, penguins use their tails and wings to maintain balance for their upright stance.

All penguins are countershaded for camouflage – that is, they have a white underside and a dark (mostly black) upperside. A predator looking up from below (such as an orca or a leopard seal) has difficulty distinguishing between a white penguin belly and the reflective water surface. The dark plumage on their backs camouflages them from above.

Diving penguins reach 6 to 12 km/h (3.7 to 7.5 mph), though there are reports of velocities of 27 km/h (17 mph) (which are more realistic in the case of startled flight). The small penguins do not usually dive deep; they catch their prey near the surface in dives that normally last only one or two minutes. Larger penguins can dive deep in case of need. Dives of the large Emperor Penguin have been recorded reaching a depth of 565 m (1,870 ft) for up to 22 minutes.

Penguins either waddle on their feet or slide on their bellies across the snow, a movement called "tobogganing", which conserves energy while moving quickly. They also jump with both feet together if they want to move more quickly or cross steep or rocky terrain.

Penguins have an average sense of hearing for birds;[28] this is used by parents and chicks to locate one another in crowded colonies.[29] Their eyes are adapted for underwater vision, and are their primary means of locating prey and avoiding predators; in air it has been suggested that they are nearsighted, although research has not supported this hypothesis.[30]

Gentoo Penguin swimming underwater at Nagasaki Penguin Aquarium.

Penguins have a thick layer of insulating feathers that keep them warm in water (heat loss in water is much greater than in air). The Emperor penguin (the largest penguin) has the largest body mass of all penguins, which further reduces relative surface area and heat loss. They also are able to control blood flow to their extremities, reducing the amount of blood that gets cold, but still keeping the extremities from freezing. In the extreme cold of the Antarctic winter, the females are at sea fishing for food leaving the males to brave the weather by themselves. They often huddle together to keep warm and rotate positions to make sure that each penguin gets a turn in the center of the heat pack.

They can drink salt water because their supraorbital gland filters excess salt from the bloodstream.[31][32][33] The salt is excreted in a concentrated fluid from the nasal passages.

The Auk of the Northern Hemisphere is superficially similar to penguins: they are not related to the penguins at all, but considered by some to be a product of moderate convergent evolution.[34]

Isabelline penguins

Isabelline Adelie Penguin on Gourdin Island.

Perhaps one in 50,000 penguins (of most species) are born with brown rather than black plumage. These are called isabelline penguins, possibly in reference to the legend that the archduchess Isabella of Austria vowed not to change her undergarments until her husband united the northern and southern Low Countries by taking the city of Ostend—which took three years to accomplish.[35] Isabellinism is different from albinism. Isabelline penguins tend to live shorter lives than normal penguins, as they are not well-camouflaged against the deep, and are often passed over as mates.

Distribution and habitat

Although all penguin species are native to the southern hemisphere, they are not found only in cold climates, such as Antarctica. In fact, only a few species of penguin actually live so far south. At least 10 species live in the temperate zone; one, the Galápagos Penguin, lives as far north as the Galápagos Islands, but this is only made possible by the cold, rich waters of the Antarctic Humboldt Current that flows around these islands.[36]

Several authors have suggested that penguins are a good example of Bergmann's Rule [37] [38] where larger bodied populations live at higher latitudes than smaller bodied populations. There is some disagreement about this, and several other authors have noted that there are fossil penguin species that contradict this hypothesis and that ocean currents and upwellings are likely to have had a greater effect on species diversity than latitude alone. [39] [40]

Major populations of penguins are found in: Antarctica, Australia, New Zealand, South America, and South Africa.[41] [42]

Behaviour

Breeding

Penguins for the most part breed in large colonies, the exceptions being the Yellow-eyed and Fiordland species; these colonies may range in size from as few as a 100 pairs for Gentoo Penguins, to several hundred thousand in the case of King, Macaroni and Chinstrap Penguins.[43] Living in colonies results in a high level of social interaction between birds, which has led to a large repertoire of visual as well as vocal displays in all penguin species.[44] Agonistic displays are those intended to confront or drive off, or alternately appease and avoid conflict with, other individuals.[44]

Penguins form monogamous pairs for a breeding season, though the rate the same pair recouples varies drastically. Most penguins lay two eggs in a clutch, although the two largest species, the Emperor and the King Penguins, lay only one.[45] With the exception of the Emperor Penguin, all penguins share the incubation duties.[46] These incubation shifts can last days and even weeks as one member of the pair feeds at sea.

Penguins generally only lay one brood; the exception is the Little Penguin, which can raise two or three broods in a season.[47]

Penguin eggs are smaller than any other bird species when compared proportionally to the weight of the parent birds; at 52 g (2 oz), the Little Penguin egg is 4.7% of its mothers' weight, and the 450 g (1 lb) Emperor Penguin egg is 2.3%.[45] The relatively thick shell forms between 10 and 16 % of the weight of a penguin egg, presumably to minimise risk of breakage in an adverse nesting environment. The yolk, too, is large, and comprises 22–31 % of the egg. Some yolk often remains when a chick is born, and is thought to help sustain it if parents are delayed in returning with food.[48]

When mothers lose a chick, they sometimes attempt to "steal" another mother's chick, usually unsuccessfully as other females in the vicinity assist the defending mother in keeping her chick. In some species, such as Emperor Penguins, young penguins assemble in large groups called crèches.

Penguins and humans

Penguins seem to have no special fear of humans, and have approached groups of explorers without hesitation. This is probably because penguins have no land predators in Antarctica or the nearby offshore islands. Instead, penguins are at risk at sea from predators such as the leopard seal. Typically, penguins do not approach closer than about 3 meters (10 ft) at which point they become nervous. This is also the distance that Antarctic tourists are told to keep from penguins (tourists are not supposed to approach closer than 3 meters, but are not expected to withdraw if the penguins come closer).

In popular culture

A penguin encounters a human during Antarctic summer.
Tux the Linux kernel mascot.

Penguins are popular around the world, primarily for their unusually upright, waddling gait and (compared to other birds) lack of fear of humans. Their striking black-and-white plumage is often likened to a tuxedo suit. Mistakenly, some artists and writers have penguins based at the North Pole. This is incorrect, as there are almost no wild penguins in the northern hemisphere, except the small group on the northernmost of the Galápagos. The cartoon series Chilly Willy helped perpetuate this myth, as the title penguin would interact with northern-hemisphere species such as polar bears and walruses.

Penguins have been the subject of many books and films such as Happy Feet and Surf's Up, both CGI films; March of the Penguins, a documentary based on the migration process of the Emperor Penguin; and a parody entitled Farce of the Penguins. Penguins have also found their way into a number of cartoons and television dramas; perhaps the most notable of these is Pingu, created by Silvio Mazzola in 1986 and covering more than 100 short episodes. Entertainment Weekly put it on its end-of-the-decade, "best-of" list, saying, "Whether they were walking (March of the Penguins), dancing (Happy Feet), or hanging ten (Surf's Up), these oddly adorable birds took flight at the box office all decade long."[49]

The tendency of penguins to form large groups feeds the stereotype that they all look exactly alike, a popular notion exploited by cartoonists such as Gary Larson.

Penguins featured regularly in the cartoons of UK cartoonist Steve Bell in his strip in The Guardian Newspaper, particularly during and following the Falklands War.

In the mid-2000s, penguins became one of the most publicized species of animals that form lasting homosexual couples. A children's book, And Tango Makes Three, was written about one such penguin family in the New York Zoo.

References

Footnotes

  1. ^ a b |title=PINGOUIN : Etymologie de PINGOUIN |first=Centre National de Ressources Textuelles et Lexicales Accessed 2010-01-25.
  2. ^ a b Online Etymology Dictionary Accessed 2010-01-25
  3. ^ Diccionario de la lengua española Accessed on 2010-01-25.
  4. ^ a b Oxford English Dictionary. Accessed 2007-03-21
  5. ^ American Heritage Dictionary at wordnik.com Accessed 2010-01-25
  6. ^ a b c Century Dictionary at wordnik.com Accessed 2010-01-25
  7. ^ Merriam-Webster Accessed 2010-01-25
  8. ^ Williams, (1995).
  9. ^ Davis & Renner, (2003).
  10. ^ Banks et al. (2002).
  11. ^ Clarke et al. (2003)
  12. ^ E.g. Clarke et al. (2003), Ksepka et al. (2006)
  13. ^ a b Clarke et al. (2003).
  14. ^ a b Bertelli & Giannini, (2005).
  15. ^ a b c d e f g h i j k l Baker et al. (2006).
  16. ^ a b c Ksepka et al. (2006).
  17. ^ a b c d Slack et al. (2006).
  18. ^ The exact divergence dates according to Baker et al. (2006) mentioned in this section are not as precisely resolved as it appears to be due to uncertainties of the molecular clock used.
  19. ^ Contra Baker et al. (2006).
  20. ^ Jadwiszczak, (2006).
  21. ^ Christidis L, Boles WE (2008). Systematics and Taxonomy of Australian Birds. Canberra: CSIRO Publishing. p. 97. ISBN 9780643065116. 
  22. ^ Ksepka, D. T. B., Sara; Giannini, Norberto P; (2006). "The phylogeny of the living and fossil Sphenisciformes (penguins)". Cladistics 22: 412–441. 
  23. ^ In fact, it is fairly likely that during the Bartonian, there was a near-synchronous but allopatric split between the ancestors of Aptenodytes, Pygoscelis, and the common ancestor of all remaining genera [Baker et al. (2006)].
  24. ^ Baker, A., Pereira, SL, Haddrath, OP, Edge, KA (2006). "Multiple gene evidence for expansion of extant penguins out of Antarctica due to global cooling". Proceedings of the Royal Society B-Biological Sciences 273. 
  25. ^ Baker, A., Pereira, SL, Haddrath, OP, Edge, KA (2006). "Multiple gene evidence for expansion of extant penguins out of Antarctica due to global cooling". Proceedings of the Royal Society B-Biological Sciences 273. 
  26. ^ Fain & Houde, (2004).
  27. ^ Mayr, (2005).
  28. ^ Wever et al. (1969).
  29. ^ Jouventin et al. (1999).
  30. ^ Sivak et al. (1987).
  31. ^ "Animal Fact Sheets". http://www.zoo.org/educate/fact_sheets/penguin/penguin.htm. Retrieved 2006-07-21. 
  32. ^ "Humboldt Penguin: Saint Louis Zoo". http://www.stlzoo.org/animals/abouttheanimals/birds/penguins/humboldtpenguin.htm. Retrieved 2006-07-21. 
  33. ^ "African Penguins and Penguins of the World". http://users.iafrica.com/b/bo/boulders/Vans%20book.htm. Retrieved 2006-07-21. 
  34. ^ Convergence and divergence in the evolution of aquatic birds by Marcel Van Tuinen, Dave Brian Butvill, John A. W. Kirsch and S. Blair Hedges
  35. ^ [1]
  36. ^ Piper, Ross (2007), Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals, Greenwood Press.
  37. ^ Ashton, K. (2002). "Patterns of within-species body size variation of birds: strong evidence for Bergmann's rule". Global Ecology and Biogeography 11: 505–523. 
  38. ^ Meiri S, D. T. (2003). "On the validity of Bergmann's rule". Journal of Biogeography 30: 331–351. 
  39. ^ Clarke, J. A., Ksepka, Daniel T., Stucchie, Marcelo, Urbina, Mario, Giannini, Norberto, Bertelli, Sara, Narvez, Yanina, Boyd, Clint A. (2007). "Paleogene equatorial penguins challenge the proposed relationship between biogeography, diversity, and Cenozoic climate change". Proceedings of the National Academy of Sciences of the United States of America 104: 11545–11550. 
  40. ^ Gohlich, U. B. (2007). "The oldest fossil record of the extant penguin genus Spheniscus-- a new species from the Miocene of Peru". Acta Palaeontologica Polonica 52: 285–298. 
  41. ^ Penguins of Australia and New Zealand
  42. ^ Jadwiszczak, P. (2009). "Penguin past: The current state of knowledge". Polish Polar Research 30: 3–28. 
  43. ^ Williams (The Penguins) p. 17
  44. ^ a b Williams (The Penguins) p. 57
  45. ^ a b Williams (The Penguins) p. 23
  46. ^ Numata, M; Davis, L & Renner, M (2000) "Prolonged foraging trips and egg desertion in little penguins (Eudyptula minor)". New Zealand Journal of Zoology 27: 291-298
  47. ^ Reilly PN, Balmford P (1975). "A breeding study of the little penguin, Eudyptula minor, in Australia". in Stonehouse, Bernard. The Biology of Penguins. London: Macmillan. pp. 161–87. ISBN 0333167910. 
  48. ^ Williams (The Penguins) p. 24
  49. ^ Geier, Thom; Jensen, Jeff; Jordan, Tina; Lyons, Margaret; Markovitz, Adam; Nashawaty, Chris; Pastorek, Whitney; Rice, Lynette; Rottenberg, Josh; Schwartz, Missy; Slezak, Michael; Snierson, Dan; Stack, Tim; Stroup, Kate; Tucker, Ken; Vary, Adam B.; Vozick-Levinson, Simon; Ward, Kate (December 11, 2009), "THE 100 Greatest MOVIES, TV SHOWS, ALBUMS, BOOKS, CHARACTERS, SCENES, EPISODES, SONGS, DRESSES, MUSIC VIDEOS, AND TRENDS THAT ENTERTAINED US OVER THE PAST 10 YEARS". Entertainment Weekly. (1079/1080):74-84

Bibliography

  • Two new fossil penguin species found in Peru
  • (Spanish) Acosta Hospitaleche, Carolina (2004): Los pingüinos (Aves, Sphenisciformes) fósiles de Patagonia. Sistemática, biogeografía y evolución. Doctoral thesis, Department of Natural Sciences and Museum, Universidad Nacional de La Plata. La Plata, Argentina. PDF fulltext
  • Baker, Allan J.; Pereira, Sergio Luiz; Haddrath, Oliver P. & Edge, Kerri-Anne (2006): Multiple gene evidence for expansion of extant penguins out of Antarctica due to global cooling. Proc. R. Soc. B 273: 11-17. doi:10.1098/rspb.2005.3260PDF fulltext
  • Banks, Jonathan C.; Mitchell, Anthony D.; Waas, Joseph R. & Paterson, Adrian M. (2002): An unexpected pattern of molecular divergence within the blue penguin (Eudyptula minor) complex. Notornis 49(1): 29–38. PDF fulltext
  • Bertelli, Sara & Giannini, Norberto P. (2005): A phylogeny of extant penguins (Aves: Sphenisciformes) combining morphology and mitochondrial sequences. Cladistics 21(3): 209–239. doi:10.1111/j.1096-0031.2005.00065.x (HTML abstract)
  • Clarke, Julia A.; Olivero, Eduardo B. & Puerta, Pablo (2003): Description of the earliest fossil penguin from South America and first Paleogene vertebrate locality of Tierra Del Fuego, Argentina. American Museum novitates 3423: 1-18. PDF fulltext
  • Davis; Lloyd S. & Renner; M. (1995). Penguins . London: T & A D Poyser. ISBN 0-7136-6550-5
  • Fain, Matthew G. & Houde, Peter (2004): Parallel radiations in the primary clades of birds. Evolution 58(11): 2558-2573. doi:10.1554/04-235 PDF fulltext
  • Jadwiszczak, Piotr (2006): Eocene penguins of Seymour Island, Antarctica: taxonomy. Polish Polar Research 27(1), 3–62. PDF fulltext
  • Jouventin, P; Aubin, T. & T Lengagne (1999) "Finding a parent in a king penguin colony: the acoustic system of individual recognition" Animal Behaviour 57: 1175–1183 [2]
  • Ksepka, Daniel T., Bertelli, Sara & Giannini, Norberto P. (2006): The phylogeny of the living and fossil Sphenisciformes (penguins). Cladistics 22(5): 412–441. doi:10.1111/j.1096-0031.2006.00116.x (HTML abstract)
  • Marples, B. J. (1962): Observations on the history of penguins. In: Leeper, G. W. (ed.), The evolution of living organisms. Melbourne, Melbourne University Press: 408-416.
  • Mayr, G. (2005): Tertiary plotopterids (Aves, Plotopteridae) and a novel hypothesis on the phylogenetic relationships of penguins (Spheniscidae). Journal of Zoological Systematics and Evolutionary Research 43(1): 61-71. doi:10.1111/j.1439-0469.2004.00291.x PDF fulltext
  • Sivak, J.; Howland, H. & McGill-Harelstad, P. (1987) "Vision of the Humboldt Penguin (Spheniscus humboldti) in Air and Water" Proceedings of the Royal Society of London. Series B, Biological Sciences. 229(1257): 467-472
  • Slack, Kerryn E.; Jones, Craig M.; Ando, Tatsuro; Harrison G. L. "Abby"; Fordyce R. Ewan; Arnason, Ulfur & Penny, David (2006): Early Penguin Fossils, plus Mitochondrial Genomes, Calibrate Avian Evolution. Molecular Biology and Evolution 23(6): 1144-1155. doi:10.1093/molbev/msj124 PDF fulltext Supplementary Material
  • Wever, E.; Herman, P.; Simmons, J. & Hertzler D (1969) "Hearing in the Blackfooted Penguin, Spheniscus demersus, as Represented by the Cochlear Potentials" PNAS 63(3): 676-680 [3]
  • Williams; Tony D. (1995). The Penguins - Spheniscidae . Oxford: Oxford University Press. ISBN 0-19-854667-X

External links


1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

PENGUIN, the name of a flightless sea-bird,' but, so far as is known, first given to one inhabiting the seas of Newfoundland as in Hore's "Voyage to Cape Breton," 1536 (Hakluyt, Researches, iii. 168-170), which subsequently became known as the great auk or garefowl (q.v.); though the French equivalent Pingouin 2 preserves its old application, the word penguin is by English ornithologists always used for certain birds inhabiting the Southern Ocean, called by the French Manchots, the Spheniscidae of ornithologists. For a long while their position was very much misunderstood, some systematists having placed them with the Alcidae or Auks, to which they bear only a relationship of analogy, as indeed had been perceived by a few ornithologists, who recognized in the penguins a very distinct order, I L. Stejneger (Standard Nat. Hist. vol. iv., Boston, 1885) gave the Impennes independent rank equivalent to the rest of Carinate birds; M. A. Menzbier (Vergl. Osteol. d. Penguine, Moscow, 1887) took a similar view; M. Fiirbringer was first to show their relation to Procellariformes, and this view is now generally accepted.

1 Of the three derivations assigned to this name, the first is by Drayton in 1613 (Polyolbion, Song 9), where it is said to be the Welsh pen gwyn, or "white head"; the second, which seems to meet with Littre's approval, deduces it from the Latin pinguis (fat), which idea has given origin to the German name, Fettgdnse, for these birds; the third supposes it to be a corruption of "pin-wing" (Ann. Nat. History, 4th series, vol. iv. p. 133), meaning a bird that has undergone the operation of pinioning or, as in one part at least of England it is commonly called, "pin-winging." The first hypothesis has been supported on the ground that Breton sailors speaking a language closely allied to Welsh were acquainted with the great auk, and that the conspicuous white patches on the head of that bird justified the name "white head." To the second hypothesis Skeat (Dictionary, p. 433) objects that it "will not account for the suffix -in, and is therefore wrong; besides which the ` Dutchmen ' [who were asserted to be the authors of the name] turn out to be Sir Francis Drake" and his men. In support of the third hypothesis Mr Reeks wrote (Zoologist, 2nd series, p. 1854) that the people in Newfoundland who used to meet with this bird always pronounced its name "pin wing." Skeat's inquiry (loc. cit.), whether the name may not after all be South American, is to be answered in the negative, since, so far as evidence goes, it was given to the North-American bird before the South-American was known in Europe.

Gorfou has also been used by some French writers, being a corruption of Geirfugl or Garefowl.

There is a total want of quills in their wings, which are incapable of flexure, though they move freely at the shoulder-joint, and some at least of the species occasionally make use of them for progressing on land. In the water they are most efficient paddles. The plumage, which clothes the whole body, generally consists of small scale-like feathers, many of them consisting only of a simple shaft without the development of barbs; but several of the species have the head decorated with long cirrhous tufts, and in some the tail-quills, which are very numerous, are also long.' In standing these birds preserve an upright position, sometimes resting on the "tarsus" 2 alone, but in walking or running this is kept nearly vertical, and their weight is supported by the toes alone.

The most northerly limit of the penguins' range in the Atlantic is Tristan d'Acunha, and in the Indian Ocean Amsterdam Island, but they also occur off the Cape of Good Hope and along the coast of Australia, as well as on the south and east of New Zealand, while in the Pacific one species at least extends along the west coast of South America and to the Galapagos; but north of the equator none are found. In the breeding season they resort to the most desolate lands in higher southern latitudes, and indeed have been met with as far to the southward as navigators have penetrated. Possibly the Falkland Islands are richest in species, though, as individuals, they King-Penguin (Aptenodytes pennanti). are not nearly so numerous there as in many other places. The food of penguins consists of crustaceans, cephalopods and other molluscs, varied by fish and vegetable matter. The birds form immense breeding colonies, known as "rookeries." The nest of grass, leaves, or where vegetation is scanty of stones or rubbish, is placed on the ground or in holes. Two chalky white or greenish eggs are laid. The young penguins, clad in thick down, are born blind and are fed by the parents for an unusually long time before taking to the water. Penguins bite savagely when molested, but are easily trained and display considerable intelligence, The Spheniscidae have been divided into at least eight genera, but three, or at most four, seem to be all that are needed, and ' The pterylographical characters of the penguins are well described by A. Hyatt (Proc. Boston Soc. Nat. History, 1871). A. D. Bartlett has observed (Proc. Zool. Soc., 1879, pp. 6-9) that, instead of moulting in the way that birds ordinarily do, penguins, at least in passing from the immature to the adult dress, cast off the short scale-like feathers from their wings in a manner that he compares to "the shedding of the skin in a serpent." 2 The three metatarsals in the penguins are not, as in other birds, united for the whole of their length, but only at the extremities, thus preserving a portion of their originally distinct existence, a fact probably attributable to arrest of development, since the researches of C. Gegenbaur show that the embryos of all birds, so far as is known, possess these bones in an independent condition.

three can be well distinguished, as pointed out by E. Coues in Proc. Acad. of Nat. Sci. of Philadelphia, 1872 (pp. 170-212), by anatomical as well as by external characters. They are: (t) Aptenodytes, easily recognized by its long and thin bill, slightly decurved, from which Pygoscelis, as M. Watson has shown, is hardly distinguishable; (2) Eudyptes, in which the bill is much shorter and rather broad; and (3) Spheniscus, in which the shortish bill is compressed and the maxilla ends in a conspicuous hook. Aptenodytes contains the largest species, among them those known as the "Emperor" and "King" penguins A. patagonica and A. longirostris. Three others belong also. to this genus, if Pygoscelis be not recognized, but they seem not to require any particular remark. Eudyptes, containing the crested penguins, known to sailors as "Rock-hoppers" or "Macaronis," would appear to have five species, and Spheniscus four, among which S. mendiculus, which occurs in the Galapagos, and therefore has the most northerly range of the whole group, alone needs notice here. (A. N.) The generic and specific distribution of the penguins is the subject of an excellent essay by Alphonse Milne-Edwards in the Annales des sciences naturelles for 1880 (vol. ix. art. 9, pp. 23-81); see also the Records of the Antarctic Expedition, 1901-1904.


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Wiktionary

Up to date as of January 15, 2010

Definition from Wiktionary, a free dictionary

See also penguin

English

Proper noun

Penguin

  1. (trademark) A particular publisher of paperback books.
  2. the Penguin (Fiction) A character in the Batman comic books and films.

Simple English

Penguins
Fossil range: Paleocene-Recent
File:Pygoscelis
Gentoo Penguin, Pygoscelis papua
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Sphenisciformes
Sharpe, 1891
Family: Spheniscidae
Bonaparte, 1831

Penguins are sea-birds. They form the family Spheniscidae, the only family of the order Sphenisciformes.

Penguins live on the southern half of the world: Antarctica, New Zealand, southern Australia, South Africa and South America.

Contents

Physical description

All penguins have a white belly and a dark (mostly black) back. Penguins cannot fly, but they can swim very well. They have good hearing and can see underwater. The white and black colors are for camouflage (to help them hide) when they swim. So, when a predator looking from underwater sees the white belly and wings of the penguin, they can not see it well with the light coming from above. Also, from above, the penguin's black backs can not be seen well in the dark water. The biggest penguins may stand nearly 4 feet tall and can weigh almost 100 pounds. The smallest kinds are only about one foot tall. Penguins also have a thick layer of blubber that helps them be warm, and their feathers are very tightly packed to make another cover. They also have a layer of woolly down under the feathers, that are coated with a type of oil that makes them waterproof.

Life

Penguins eat krill or fish and are at home in the ocean. They come up on the land or ice to lay their eggs and raise the chicks. The animals all nest together in a huge group, called a rookery. They usually make nests on the ground with rocks or mud.

After the penguins mate, the mother lays her egg on the ice before winter. She lets the father take care of it by putting it on his foot and covering it up with his warm belly. The mother then goes for two months to live in the ocean, eating and eating, and getting fat. The fathers all huddle together in a group to help protect each others' eggs. They do not eat anything, but live off the fat on their bodies.

When the baby penguin comes out of the egg, the father gives it a milk-like liquid that he makes inside his throat. Soon, the mother joins them and gives the baby some food. The hungry father will go out to the ocean and find some food. He will return after weeks and then the two of the parents will take turns going out, finding food, and coming back to take care of their chick. penguins eat krill, fish, squid, and other small animals from the ocean, which they catch.

Different kinds

There are 16-19 living species (types) of penguins. The White-flippered Penguin is today generally considered a subspecies of the Little Penguin. It is still unclear if the Royal Penguin is a subspecies of the Macaroni Penguin. It is also possible that northern and southern Rockhopper Penguins are separate species.

Penguins sorts

  • Aptenodytes
  • Pygoscelis
    • Gentoo Penguin (Pygoscelis papua)
    • Adelie Penguin (Pygoscelis adeliae)
    • Chinstrap Penguin (Pygoscelis Antarctica)
  • Eudyptes
    • Rockhopper Penguin (Eudyptes chrysocome)
    • Fiordland Penguin (Eudyptes pachyrhynchus)
    • Snares Penguin (Eudyptes robustus)
    • Royal Penguin (Eudyptes schlegeli)
    • Erect-crested Penguin (Eudyptes sclateri)
    • Macaroni Penguin (Eudyptes chrysolophus)
  • Megadyptes
    • Yellow-eyed Penguin (Megadyptes antipodes)
  • Eudyptula
    • Little Penguin (Eudyptula minor)
    • White-flippered Penguin (Eudyptula albosignata)
  • Spheniscus
    • African Penguin (Spheniscus demersus)
    • Magellanic Penguin (Spheniscus magellanicus)
    • Humboldt Penguin (Spheniscus humboldti)
    • Galápagos Penguin (Spheniscus mendiculus)

Images

Other pages

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Look up Spheniscidae in Wikispecies, a directory of species








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