Palaeeudyptinae
Encyclopedia
The New Zealand Giant Penguins, Palaeeudyptinae, are an extinct subfamily of penguins. It includes several genera
of medium-sized to very large species - including Palaeeudyptes marplesi
and Anthropornis nordenskjoeldi
which grew 1.5 metre tall or even larger, and the massive Pachydyptes ponderosus which weighed at least as much as an adult human
male.
They belonged to an evolution
ary lineage more primitive than modern penguins. In some taxa at least, the wing, while already having lost the avian
feather
ing, had not yet transformed into the semi-rigid flipper found in modern penguin species: While the ulna
and the radius
were already flattened to increase propelling capacity, the elbow and wrist
joint
s still retained a higher degree of flexibility than the more rigidly lockable structure found in modern genera. The decline and eventual disappearance of this subfamily seems to be connected to increased competition as mammal
groups such as cetaceans and pinnipeds became better-adapted to a marine lifestyle in the Oligocene
and Miocene
.
The members of this subfamily are known from fossils found in New Zealand
, Antarctica, and possibly Australia
, dating from the Middle or Late Eocene
to the Late Oligocene
; the Australian Middle Miocene
genus Anthropodyptes
is also often assigned to this subfamily, as are the remaining genera of primitive penguins except those from Patagonia
. Indeed, it was long assumed that all prehistoric penguins which cannot be assigned to extant genera belonged into the Palaeeudyptinae; this view is generally considered obsolete today. It is likely that some of the unassigned New Zealand/Antarctican/Australian genera like Delphinornis, Marambiornis, and Mesetaornis do indeed belong into this subfamily, but it is just as probable that others, such as Duntroonornis and Korora, represent another, smaller and possibly somewhat more advanced lineage.
The Palaeeudyptinae as originally defined (Simpson, 1946) contained only the namesake genus, the remainder being placed in the Anthropornithidae. The arrangement followed here is based on the review of Marples (1962) who synonymized the two, with updates to incorporate more current findings.
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...
of medium-sized to very large species - including Palaeeudyptes marplesi
Palaeeudyptes marplesi
Marples' Penguin was a large species of the extinct penguin genus Palaeeudyptes. It stood between 105 and 145 cm high in life, larger than the present Emperor Penguin. The precise relationship between this species and the slightly smaller Narrow-flippered Penguin from somewhat younger rocks is...
and Anthropornis nordenskjoeldi
Anthropornis nordenskjoeldi
Anthropornis is a genus of giant penguin that lived 37-45 million years ago, during the Late Eocene and the earliest part of the Oligocene. It reached in height and in weight. Fossils of it have been found on Seymour Island off the coast of Antarctica and in New Zealand...
which grew 1.5 metre tall or even larger, and the massive Pachydyptes ponderosus which weighed at least as much as an adult human
Human
Humans are the only living species in the Homo genus...
male.
They belonged to an evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
ary lineage more primitive than modern penguins. In some taxa at least, the wing, while already having lost the avian
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
feather
Feather
Feathers are one of the epidermal growths that form the distinctive outer covering, or plumage, on birds and some non-avian theropod dinosaurs. They are considered the most complex integumentary structures found in vertebrates, and indeed a premier example of a complex evolutionary novelty. They...
ing, had not yet transformed into the semi-rigid flipper found in modern penguin species: While the ulna
Ulna
The ulna is one of the two long bones in the forearm, the other being the radius. It is prismatic in form and runs parallel to the radius, which is shorter and smaller. In anatomical position The ulna is one of the two long bones in the forearm, the other being the radius. It is prismatic in form...
and the radius
Radius
In classical geometry, a radius of a circle or sphere is any line segment from its center to its perimeter. By extension, the radius of a circle or sphere is the length of any such segment, which is half the diameter. If the object does not have an obvious center, the term may refer to its...
were already flattened to increase propelling capacity, the elbow and wrist
Wrist
In human anatomy, the wrist is variously defined as 1) the carpus or carpal bones, the complex of eight bones forming the proximal skeletal segment of the hand;...
joint
Joint
A joint is the location at which two or more bones make contact. They are constructed to allow movement and provide mechanical support, and are classified structurally and functionally.-Classification:...
s still retained a higher degree of flexibility than the more rigidly lockable structure found in modern genera. The decline and eventual disappearance of this subfamily seems to be connected to increased competition as mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
groups such as cetaceans and pinnipeds became better-adapted to a marine lifestyle in the Oligocene
Oligocene
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...
and Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
.
The members of this subfamily are known from fossils found in New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
, Antarctica, and possibly Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, dating from the Middle or Late Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
to the Late Oligocene
Oligocene
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...
; the Australian Middle Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
genus Anthropodyptes
Anthropodyptes
-References:* Simpson, George Gaylord : A review of the pre-Pleistocene penguins of New Zealand. Bulletin of the American Museum of Natural History 144: 319–378....
is also often assigned to this subfamily, as are the remaining genera of primitive penguins except those from Patagonia
Patagonia
Patagonia is a region located in Argentina and Chile, integrating the southernmost section of the Andes mountains to the southwest towards the Pacific ocean and from the east of the cordillera to the valleys it follows south through Colorado River towards Carmen de Patagones in the Atlantic Ocean...
. Indeed, it was long assumed that all prehistoric penguins which cannot be assigned to extant genera belonged into the Palaeeudyptinae; this view is generally considered obsolete today. It is likely that some of the unassigned New Zealand/Antarctican/Australian genera like Delphinornis, Marambiornis, and Mesetaornis do indeed belong into this subfamily, but it is just as probable that others, such as Duntroonornis and Korora, represent another, smaller and possibly somewhat more advanced lineage.
The Palaeeudyptinae as originally defined (Simpson, 1946) contained only the namesake genus, the remainder being placed in the Anthropornithidae. The arrangement followed here is based on the review of Marples (1962) who synonymized the two, with updates to incorporate more current findings.