| Icadyptes | |
|---|---|
 | |
| Icadyptes salasi | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Sphenisciformes |
| Family: | Spheniscidae |
| Genus: | † Icadyptes |
| Species: | †I. salasi |
| Binomial name | |
| †Icadyptes salasi | |
Icadyptes is an extinct genus of giant penguins from the Late Eocene tropics of South America.
The genus name is a combination of "Ica" for the Peruvian region where the type species was found and "dyptes" from the Greek word for diver. The species epithet "salasi" refers to Rodolfo Salas Gismondi, a noted Peruvian paleontologist.
Standing about 1.5 metres (4.9 ft) tall, the penguin was much larger than any of its modern-day cousins, yet Icadyptes salasi is merely the third largest penguin ever described. [2] It had an exceptionally long spear-like beak resembling that of a heron. The researchers who discovered the penguins believe the long, pointed beaks to be the likely ancestral shape for all penguins.
The fossilised remains of the penguin, which lived approximately 36 million years ago, were found in the Otuma Formation, [3] in the coastal desert of Peru by the team of North Carolina State University palaeontologist Dr. Julia Clarke, assistant professor of marine, earth and atmospheric sciences. Its well-preserved Fossil skeleton was found on the southern coast of Peru together with an early Eocene species Perudyptes devriesi (comparable in size to the living King penguin), and the remains of three other previously undescribed penguin species, all of which seem to have preferred the tropics over colder latitudes.
Icadyptes salasi and Perudyptes devriesi appear to have flourished at warmer latitudes at a time when world temperatures were at their warmest over the past 65 million years. Only a few modern-day penguins, such as the African and Galapagos penguins prefer such a balmy climate.
The discovery of the fossils has caused a re-evaluation of penguin evolution and expansion. Previously, scientists believed that penguins evolved near the poles in Antarctica and New Zealand, and moved closer to the equator around 10 million years ago. Since Icadyptes salasi lived in Peru during a period of great warmth, penguins must have adapted to warm climates around 30 million years earlier than previously believed. [4]
The Eocene Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name Eocene comes from the Ancient Greek ἠώς and καινός and refers to the "dawn" of modern ('new') fauna that appeared during the epoch.
Penguins are a group of aquatic flightless birds. They live almost exclusively in the Southern Hemisphere: only one species, the Galápagos penguin, is found north of the Equator. Highly adapted for life in the water, penguins have countershaded dark and white plumage and flippers for swimming. Most penguins feed on krill, fish, squid and other forms of sea life which they catch with their bills and swallow it whole while swimming. A penguin has a spiny tongue and powerful jaws to grip slippery prey.
In geography, the temperate climates of Earth occur in the middle latitudes, which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout the year and more distinct seasonal changes compared to tropical climates, where such variations are often small and usually only have precipitation changes.
The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at 23°26′10.8″ (or 23.43635°) N and the Tropic of Capricorn in the Southern Hemisphere at 23°26′10.8″ (or 23.43635°) S; these latitudes correspond to the axial tilt of the Earth. The tropics are also referred to as the tropical zone and the torrid zone. The tropics also includes everywhere on Earth which is a subsolar point at least once during the solar year. Thus the maximum latitudes of the tropics have the same value positive and negative. Likewise, they approximate the angle of the Earth's axial tilt. The "angle" itself is not perfectly fixed due chiefly to the influence of the moon, but the limits of tropics are a geographic convention, being an averaged form, and the variance is very small.
Coraciidae is a family of Old World birds, which is known as rollers because of the aerial acrobatics some of these birds perform during courtship or territorial flights. Rollers resemble crows in size and build, and share the colourful appearance of kingfishers and bee-eaters, blues and pinkish or cinnamon browns predominating. The two inner front toes are connected, but not the outer one.
The Antarctic Peninsula, known as O'Higgins Land in Chile and Tierra de San Martín in Argentina, and originally as Graham Land in the United Kingdom and the Palmer Peninsula in the United States, is the northernmost part of mainland Antarctica.
Ica is a city and the capital of the Department of Ica in southern Peru. While the area was long inhabited by varying cultures of indigenous peoples, the Spanish conquistador Jerónimo Luis de Cabrera claimed its founding in 1563.
Leptictidium is an extinct genus of small mammals that were likely bipedal. Comprising eight species, they resembled today's bilbies, bandicoots, and elephant shrews. They are especially interesting for their combination of characteristics typical of primitive eutherians with highly specialized adaptations, such as powerful hind legs and a long tail which aided in locomotion. They were omnivorous, their diet a combination of insects, lizards and small mammals. Lepticidium and other lepticids are not placentals, but are non-placentral eutherians, although closely related. They appeared in the Lower Eocene, a time of warm temperatures and high humidity, roughly fifty million years ago. Although they were widespread throughout Europe, they became extinct around thirty-five million years ago with no descendants, probably because they were adapted to live in forest ecosystems and were unable to adapt to the open plains of the Oligocene.
Anthropornis is a genus of giant penguin that lived 45-33 million years ago, during the Late Eocene and the earliest part of the Oligocene. It reached 1.8 m in length from the tip of the beak to the tip of the tail, and 90 kg (200 lb) in weight. Fossils of it have been found in the La Meseta Formation on Seymour Island off the coast of Antarctica and in New Zealand. By comparison, the largest modern penguin species, the emperor penguin, is just 1.2 m long.
Pachydyptes is an extinct genus of penguin. It contains the single species Pachydyptes ponderosus, the New Zealand giant penguin. This taxon is known from a few bones from Late Eocene rocks in the area of Otago, which were found in two clades near a base of a tree.
Palaeeudyptinae, the giant penguins, is a paraphyletic subfamily of prehistoric penguins. It includes several genera of medium-sized to very large species, such as Icadyptes salasi, Palaeeudyptes marplesi, Anthropornis nordenskjoeldi, and Pachydyptes ponderosus. Icadyptes reached 1.5 m in height, while members of Palaeeudyptes and Anthropornis grew even taller and were some of the largest penguins to have ever existed. The massive P. ponderosus may have weighed at least as much as an adult human.
Throughout Earth's climate history (Paleoclimate) its climate has fluctuated between two primary states: greenhouse and icehouse Earth. Both climate states last for millions of years and should not be confused with glacial and interglacial periods, which occur as alternate phases within an icehouse period and tend to last less than 1 million years. There are five known Icehouse periods in Earth's climate history, which are known as the Huronian, Cryogenian, Andean-Saharan, Late Paleozoic, and Late Cenozoic glaciations. The main factors involved in changes of the paleoclimate are believed to be the concentration of atmospheric carbon dioxide, changes in Earth's orbit, long-term changes in the solar constant, and oceanic and orogenic changes from tectonic plate dynamics. Greenhouse and icehouse periods have played key roles in the evolution of life on Earth by directly and indirectly forcing biotic adaptation and turnover at various spatial scales across time.
Lithornithidae is an extinct, possibly paraphyletic group of early paleognath birds. They are known from fossils dating to the Upper Paleocene through the Middle Eocene of North America and Europe, with possible Late Cretaceous representatives. All are extinct today; the youngest specimen is the currently unnamed SGPIMH MEV1 specimen from the mid-Eocene Messel Pit site.
The Cretaceous Thermal Maximum (CTM), also known as Cretaceous Thermal Optimum, was a period of climatic warming that reached its peak approximately 90 million years ago during the Turonian age of the Late Cretaceous epoch. The CTM is notable for its dramatic increase in global temperatures characterized by high carbon dioxide levels.
Inkayacu is a genus of extinct penguins. It lived in what is now Peru during the Late Eocene, around 36 million years ago. A nearly complete skeleton was discovered in 2008 and includes fossilized feathers, the first known in penguins. A study of the melanosomes, pigment-containing organelles within the feathers, indicated that they were gray or reddish brown. This differs from modern penguins, which get their dark black-brown feathers from unique melanosomes that are large and ellipsoidal.
Kairuku grebneffi is an extinct species of giant penguin. It is among the tallest and heaviest penguins attested to, weighing 50% more than modern emperor penguins. The species is marked by a slender body and long, slender bill. K. grebneffi lived in what is now New Zealand during the late Oligocene, going extinct around 25 million years ago. Bones of the species were first discovered in 1977, but it was not classified as a distinct species until 2012.
Perudyptes is a basal penguin from the Middle Eocene Paracas Formation of Peru. The genus name Perudyptes is named after the country, while the species name devriesi Thomas DeVries, a Vashon Island High School science teacher who has long worked in Peru.
Llanocetus is a genus of extinct toothed baleen whales from the Late Eocene of Antarctica. The type species, Llanocetus denticrinatus, reached gigantic proportions, with the juvenile specimen reaching an estimated 8 m (26 ft) in length; a second, unnamed species, known only from three isolated premolar teeth, reached an estimated total body length of up to 12 m (39 ft). Like other contemporary baleen whales of the Eocene, Llanocetus completely lacked baleen in its jaws. It was probably a suction feeder like the modern beaked and pygmy right whales.
Septencoracias is an extinct genus of bird related to modern rollers and other Coraciiformes such as kingfishers, bee-eaters, motmots, and todies. It contains one species, Septencoracias morsensis. It was found in the Fur Formation of Denmark, dating back to the Ypresian of the Lower Eocene Epoch, about 54 million years ago. Septencoracias is one of the earliest known members of Coraciiformes, lending insight into the earliest radiation of this group.
Julia Allison Clarke is an American paleontologist who is particularly interested in bird evolution and the dinosaurs most closely related to living birds. She works at the University of Texas where she is the John A. Wilson Professor in Vertebrate Paleontology.
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