Portal:Paleontology

Abelisauridae (meaning "Abel's lizards") is a family (or clade) of ceratosaurian theropod dinosaurs. Abelisaurids thrived during the Cretaceous Period, on the ancient southern supercontinent of Gondwana, and today their fossil remains are found on the modern continents of Africa and South America, as well as on the Indian subcontinent and the island of Madagascar. Abelisaurids first appear in the fossil record of the early middle Jurassic period, and at least one species (Majungasaurus crenatissimus) survived until the end of the Mesozoic era 66 million years ago.

Like most theropods, abelisaurids were carnivorous bipeds. They were characterized by stocky hindlimbs and extensive ornamentation of the skull bones, with grooves and pits. In many abelisaurids, like Carnotaurus, the forelimbs are vestigial, the skull is shorter and bony crests grows above the eyes. Most of the known abelisaurids would have been between 5 and 9 meters (17 to 30 ft) in length, from snout to tip of tail, with a new and as yet unnamed specimen from northwestern Turkana in Kenya, Africa reaching a possible length of 11–12 meters (36 to 39 feet). Before becoming well known, fragmentary abelisaurid remains were occasionally misidentified as possible South American tyrannosaurids. (see more...)

Charles Darwin (12 February 1809 – 19 April 1882) was an English naturalist and geologist, best known for his contributions to evolutionary theory. He established that all species of life have descended over time from common ancestors, and in a joint publication with Alfred Russel Wallace introduced his scientific theory that this branching pattern of evolution resulted from a process that he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding.

His five-year voyage on HMS Beagle established him as an eminent geologist whose observations and theories supported Charles Lyell's uniformitarian ideas. Darwin later published his theory of evolution with compelling evidence in his 1859 book On the Origin of Species, overcoming scientific rejection of earlier concepts of transmutation of species. By the 1870s the scientific community and much of the general public had accepted evolution as a fact. However, many favoured competing explanations and it was not until the emergence of the modern evolutionary synthesis from the 1930s to the 1950s that a broad consensus developed in which natural selection was the basic mechanism of evolution. In modified form, Darwin's scientific discovery is the unifying theory of the life sciences, explaining the diversity of life.

In recognition of Darwin's pre-eminence as a scientist, he was honoured with a major ceremonial funeral and buried in Westminster Abbey, close to John Herschel and Isaac Newton. Darwin has been described as one of the most influential figures in human history. (see more...)

June 25:

• 1854 - Charles Depéret was born in Perpignan, France.
• 1859 - Gerhard Heilmann was born in Skelskør, Denmark.
• 1866 - Alexander von Nordmann died of heart failure in Helsinki, Finland.
• 1889 - Paul Fallot was born in Strasbourg, France.
• 1892 - Jan Czerski died during a fossil hunting expedition to the Kolyma, Yana and Indigirka Rivers.
• 1901 - Chester A. Arnold was born in Leeton, Missouri.
• 1965 - Sabine Gaudzinski-Windheuser

The Completeness of the Fossil Record of Mesozoic Birds: Implications for Early Avian Evolution

Neil Brocklehurst, Paul Upchurch, Philip D. Mannion, Jingmai O'Connor

published 25 Jun 2012

Avian Cerebellar Floccular Fossa Size Is Not a Proxy for Flying Ability in Birds

Stig A. Walsh, Andrew N. Iwaniuk, Monja A. Knoll, Estelle Bourdon, Paul M. Barrett, Angela C. Milner, Robert L. Nudds, Richard L. Abel, Patricia Dello Sterpaio

published 25 Jun 2013

More anniversaries...

• WikiProject Palaeontology
• WikiProject Science