Eudyptes
Encyclopedia
The term crested penguin is the name given to several species of penguin
Penguin
Penguins 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...

 of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Eudyptes. The exact number varies between four and seven depending on the authority, and a Chatham Islands
Chatham Islands
The Chatham Islands are an archipelago and New Zealand territory in the Pacific Ocean consisting of about ten islands within a radius, the largest of which are Chatham Island and Pitt Island. Their name in the indigenous language, Moriori, means Misty Sun...

 species may have become extinct in the 19th century. All are black and white penguins with yellow crests and red bills and eyes, and are found on subantarctic islands in the worlds southern oceans. All lay two eggs but raise only one young per breeding season; the first egg laid is substantially smaller than the second.

Taxonomy

The genus was described by the French ornithologist Louis Jean Pierre Vieillot
Louis Jean Pierre Vieillot
Louis Jean Pierre Vieillot was a French ornithologist.Vieillot described a large number of birds for the first time, especially those he encountered during the time he spent in the West Indies and North America, and 26 genera established by him are still in use...

 in 1816; the name is derived from the Ancient Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...

 words eu "good", and dyptes "diver".

Six extant species have been classically recognised, with the recent splitting of the Rockhopper Penguin increasing it to seven. Conversely, the close relationship of the Macaroni and Royal Penguins, and the Erect-crested and Snares Penguins have led some to propose the two pairs should be regarded as species.

ORDER SPHENISCIFORMES
  • Family Spheniscidae
    • Fiordland Penguin
      Fiordland Penguin
      The Fiordland Crested Penguin , also known as Tawaki , is a species of crested penguin from New Zealand...

      , Eudyptes pachyrhynchus
    • Snares Penguin
      Snares Penguin
      The Snares Penguin , also known as the Snares Crested Penguin and the Snares Islands Penguin, is a penguin from New Zealand...

      , Eudyptes robustus – has been considered a subspecies of the Fiordland Penguin.
    • Erect-crested Penguin
      Erect-crested Penguin
      The Erect-crested Penguin is a penguin from New Zealand. It breeds on the Bounty and Antipodes Islands.This is a small-to-medium-sized, yellow-crested, black-and-white penguin, at and weighing . As in all penguin species, the male is slightly larger than the female and the birds weigh the most...

      , Eudyptes sclateri
    • Southern Rockhopper Penguin
      Southern Rockhopper Penguin
      The Southern Rockhopper Penguin group , are two subspecies of rockhopper penguin, that together are sometimes considered distinct from the Northern Rockhopper Penguin...

      , Eudyptes chrysocome
      • Eastern Rockhopper Penguin
        Eastern Rockhopper Penguin
        The Eastern Rockhopper Penguin although genetically differnt is still often considered as a subspecies of the Southern Rockhopper Penguin.-Distribution:...

        , Eudyptes (chrysocome) filholi
      • Western Rockhopper Penguin, Eudyptes (chrysocome) chrysocome
    • Northern Rockhopper Penguin
      Northern Rockhopper Penguin
      The Northern Rockhopper Penguin, Eudyptes c. moseleyi, is usually considered a subspecies of rockhopper penguin, although fairly recent studies show evidence of distinction from the Southern Rockhopper Penguin group Eudyptes c. chrysocome/E. c. filholi.A study published in 2009 showed that the...

      , Eudyptes moseleyi – traditionally considered a subspecies of Eudyptes chrysocome as the Rockhopper Penguin.
    • Royal Penguin
      Royal Penguin
      The Royal Penguin inhabits the waters surrounding Antarctica. Royals look very much like Macaroni Penguins, but have a white face and chin instead of the Macaronis' black visage. They are long and weigh . Males are larger than females...

      , Eudyptes schlegeli – sometimes considered a morph of E. chrysolophus
    • Macaroni Penguin
      Macaroni Penguin
      The Macaroni Penguin is a species of penguin found from the Subantarctic to the Antarctic Peninsula. One of six species of crested penguin, it is very closely related to the Royal Penguin, and some authorities consider the two to be a single species...

      , Eudyptes chrysolophus
    • Chatham Penguin, Eudyptes chathamensis. (prehistoric
      Late Quaternary prehistoric birds
      Prehistoric birds are various taxa of birds that became extinct before recorded history, or more precisely, before they could be studied alive by bird scientists...

      ?)

The Chatham Islands
Chatham Islands
The Chatham Islands are an archipelago and New Zealand territory in the Pacific Ocean consisting of about ten islands within a radius, the largest of which are Chatham Island and Pitt Island. Their name in the indigenous language, Moriori, means Misty Sun...

 form is known only from subfossil
Subfossil
Subfossil refers to remains whose fossilization process is not complete, either for lack of time or because the conditions in which they were buried were not optimal for fossilization....

 bones, but may have become extinct as recently as the late 19th century as a bird kept captive at some time between 1867 and 1872 might refer to this taxon. It appears to have been a distinct species, with a thin, slim and low bill.

Evolution

Mitochondrial and nuclear
Cell nucleus
In cell biology, the nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these...

 DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

 evidence suggests the Crested Penguins split from ancestors of their closest relative, the Yellow-eyed Penguin
Yellow-eyed Penguin
The Yellow-eyed Penguin or Hoiho is a penguin native to New Zealand. Previously thought closely related to the Little Penguin , molecular research has shown it more closely related to penguins of the genus Eudyptes...

, around 15 million years ago, before splitting into separate species around 8 million years ago.

Description

The crested penguins are similar in appearance, having sharply delineated black and white plumage with red beaks and prominent yellow crests. Their calls are more complex than those of other species, with several phrases of differing lengths. The Royal Penguin (mostly) has a white face, while other species have black faces.

Breeding

Crested penguins breed on subantarctic islands in the southern reaches of the world's oceans; the greatest diversity occurring around New Zealand and surrounding islands. Their breeding displays and behaviours are generally more complex than other penguin species. Both male and female parents take shifts incubating
Avian incubation
Incubation refers to the process by which certain oviparous animals hatch their eggs, and to the development of the embryo within the egg. The most vital factor of incubation is the constant temperature required for its development over a specific period. Especially in domestic fowl, the act of...

 eggs and young.

Crested penguins lay two eggs but almost always raise only one young successfully. All species exhibit the odd phenomenon of egg-size dimorphism in breeding; the first egg (or A-egg) laid is substantially smaller than the second egg (B-egg). This is most extreme in the Macaroni Penguin
Macaroni Penguin
The Macaroni Penguin is a species of penguin found from the Subantarctic to the Antarctic Peninsula. One of six species of crested penguin, it is very closely related to the Royal Penguin, and some authorities consider the two to be a single species...

, where the first egg averages only 60% the size of the second. The reason for this is a mystery, although several theories have been proposed, remains unknown. British ornithologist David Lack
David Lack
David Lambert Lack FRS, was a British evolutionary biologist who made contributions to ornithology, ecology and ethology. His book on the finches of the Galapagos Islands was a landmark work.- Early life :...

theorized the genus was evolving toward the laying of a one-egg clutch. Experiments with egg substitution have shown that A-eggs can produce viable chicks which were only 7% lighter at time of fledging.

Recently, brooding Royal and Erect-crested Penguins have been reported to tip the smaller eggs out as the second is laid.

External links

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