Portal:Paleontology

The Paleontology Portal

A paleontologist at work at John Day Fossil Beds National Monument

Paleontology (/ˌpeɪliɒnˈtɒlədʒi, ˌpæli-, -ən-/), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossils to classify organisms and study their interactions with each other and their environments (their paleoecology). Paleontological observations have been documented as far back as the 5th century BCE. The science became established in the 18th century as a result of Georges Cuvier's work on comparative anatomy, and developed rapidly in the 19th century. The term itself originates from Greek παλα ('palaios', "old, ancient"), ὄν ('on', (gen. 'ontos'), "being, creature"), and λόγος ('logos', "speech, thought, study").

Paleontology lies on the border between biology and geology, but differs from archaeology in that it excludes the study of anatomically modern humans. It now uses techniques drawn from a wide range of sciences, including biochemistry, mathematics, and engineering. Use of all these techniques has enabled paleontologists to discover much of the evolutionary history of life, almost all the way back to when Earth became capable of supporting life, almost 4 billion years ago. As knowledge has increased, paleontology has developed specialised sub-divisions, some of which focus on different types of fossil organisms while others study ecology and environmental history, such as ancient climates.

Body fossils and trace fossils are the principal types of evidence about ancient life, and geochemical evidence has helped to decipher the evolution of life before there were organisms large enough to leave body fossils. Estimating the dates of these remains is essential but difficult: sometimes adjacent rock layers allow radiometric dating, which provides absolute dates that are accurate to within 0.5%, but more often paleontologists have to rely on relative dating by solving the "jigsaw puzzles" of biostratigraphy (arrangement of rock layers from youngest to oldest). Classifying ancient organisms is also difficult, as many do not fit well into the Linnaean taxonomy classifying living organisms, and paleontologists more often use cladistics to draw up evolutionary "family trees". The final quarter of the 20th century saw the development of molecular phylogenetics, which investigates how closely organisms are related by measuring the similarity of the DNA in their genomes. Molecular phylogenetics has also been used to estimate the dates when species diverged, but there is controversy about the reliability of the molecular clock on which such estimates depend. (Full article...)

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On this day...

December 5:

1839 - Franz Martin Hilgendorf was born in Neudamm (Mark Brandenburg), Germany.
1876 - Charles Anderson was born in Stenness, Scotland.
2008 - Rodolfo Casamiquela died in Cipolletti, Río Negro Province, Argentina.

Cavemen Were Better at Depicting Quadruped Walking than Modern Artists: Erroneous Walking Illustrations in the Fine Arts from Prehistory to Today

Gabor Horvath, Etelka Farkas, Ildiko Boncz, Miklos Blaho, Gyorgy Kriska

published 05 Dec 2012

Pedal Claw Curvature in Birds, Lizards and Mesozoic Dinosaurs – Complicated Categories and Compensating for Mass-Specific and Phylogenetic Control

Aleksandra V. Birn-Jeffery, Charlotte E. Miller, Darren Naish, Emily J. Rayfield, David W. E. Hone

published 05 Dec 2012

Large-Diameter Burrows of the Triassic Ischigualasto Basin, NW Argentina: Paleoecological and Paleoenvironmental Implications

Carina E. Colombi, Eliana Fernández, Brian S. Currie, Oscar A. Alcober, Ricardo Martínez, Gustavo Correa

published 05 Dec 2012

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Selected article on the prehistoric world and its legacies

Artist's reconstruction of Waptia fieldensis.

The small shelly fauna or small shelly fossils, abbreviated to SSF, are mineralized fossils, many only a few millimetres long, with a nearly continuous record from the latest stages of the Ediacaran to the end of the Early Cambrian period. They are very diverse, and there is no formal definition of "small shelly fauna" or "small shelly fossils". Almost all are from earlier rocks than more familiar fossils such as trilobites. Since most SSFs were preserved by being covered quickly with phosphate and this method of preservation is mainly limited to the Late Ediacaran and Early Cambrian periods, the animals that made them may actually have arisen earlier and persisted after this time span.

The bulk of the fossils are fragments or disarticulated remains of larger organisms, including sponges, molluscs, slug-like halkieriids, brachiopods, echinoderms, and onychophoran-like organisms that may have been close to the ancestors of arthropods. Although the small size and often fragmentary nature of SSFs makes it difficult to identify and classify them, they provide very important evidence for how the main groups of marine invertebrates evolved, and particularly for the pace and pattern of evolution in the Cambrian explosion. Besides including the earliest known representatives of some modern phyla, they have the great advantage of presenting a nearly continuous record of Early Cambrian organisms whose bodies include hard parts. (see more...)

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Selected article on paleontology in human science, culture and economics

Two Iguanodon sculptures at the crystal palace.

The Crystal Palace Dinosaurs, also known as Dinosaur Court, are a series of sculptures of extinct animals (including dinosaurs) and mammals in Crystal Palace Park, now in the London borough of Bromley. Commissioned in 1852 to accompany the Crystal Palace after its move from the Great Exhibition in Hyde Park and unveiled in 1854, they were the first dinosaur sculptures in the world, pre-dating the publication of Charles Darwin's On the Origin of Species by six years. While to varying degrees inaccurate by modern standards, the models were designed and sculpted by Benjamin Waterhouse Hawkins under the scientific direction of Sir Richard Owen, representing the latest scientific knowledge at the time. The models were classed as Grade II listed buildings from 1973, extensively restored in 2002, and upgraded to Grade I listed in 2007.

The models represent fifteen genera of extinct animals, not all dinosaurs. They are from a wide range of geological ages, and include true dinosaurs, ichthyosaurs, and plesiosaurs mainly from the Mesozoic era, and some mammals from the more recent Cenozoic era. (see more...)

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Did you know?

... that one species of the extinct Eocene bulldog ant Ypresiomyrma reached up to 25 millimetres (0.98 in) in length?
... that the discovery of the fossil of Shenshou, a squirrel-like early mammal from the Tiaojishan Formation, pushed the origin of mammals back to the Late Triassic, 220 million to 200 million years ago?
... that Gustava Aigner made the first discovery of graptolites in the northern greywacke zone of the Alps, with her former fellow student, Ida Peltzmann, who named two species for her?
... that the extinct sumac Rhus rooseae was described from fossils over 35 million years old?
... that the clawless lobster Tricarina is known from a single fossil, obtained from an oil well 3,852 m (12,638 ft) below ground in western Iran?

... that the parareptile Eunotosaurus (restoration pictured) was once widely accepted as a transitional form between turtles and their prehistoric ancestors?
... that the extinct incense-cedar Calocedrus huashanensis is one of only three conifers found in the Ningming Formation?
...that corals, graptolites, brachiopods and trilobites are frequently used as index fossils?
... that the discovery of Babakotia radofilai, an extinct species of sloth lemur, helped to resolve the relationship between the indriids, sloth lemurs, and monkey lemurs?
... that researchers have identified the pictured life form which no longer lives on this planet?

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Selected image

The middle of a polished 15.34 cm × 18.04 cm slice of a petrified tree from Arizona, USA. After the enlargement of the image it is possible to see insect borings in the wood. The tree lived approximately 230 million years ago during the Late Triassic.
Photo credit: Michael Gäbler