The Paleozoic Era (from the Greek palaios (παλαιός), "old" and zoe (ζωή), "life", meaning "ancient life") is the earliest of three geologic eras of the Phanerozoic Eon, spanning from roughly 542 to 251 million years ago (ICS, 2004). It is the longest of the Phanerozoic eras, and is subdivided into six geologic periods (from oldest to youngest): the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian. The Paleozoic comes after the Neoproterozoic era of the Proterozoic eon, and is followed by the Mesozoic era.

The Paleozoic was a time of dramatic geological, climatic, and evolutionary change. The Cambrian Period witnessed the most rapid and widespread diversification of life in Earth's history, known as the Cambrian explosion, in which most modern phyla first appeared. Fish, arthropods, amphibians and reptiles all evolved during the Paleozoic. Life began in the ocean but eventually transitioned onto land, and by the late Paleozoic, it was dominated by various forms of organisms. Great forests of primitive plants covered the continents, many of which formed the coal beds of Europe and eastern North America. Towards the end of the era, large, sophisticated reptiles were dominant and the first modern plants (conifers) appeared.

The Paleozoic Era ended with the largest mass extinction in Earth's history, the Permian–Triassic extinction event. The effects of this catastrophe were so devastating that it took life on land 30 million years into the Mesozoic to recover.^[1] Recovery of life in the sea may have been much faster.^[2]

Geology[link]

In North America, the era began with deep sedimentary basins along the eastern, southeastern, and western sides of the continent, while the interior was dry land. As the era proceeded, the marginal seas periodically washed over the stable interior, leaving sedimentary deposits to mark their incursions. During the early part of the era, the area of exposed Precambrian, or shield, rocks in central Canada were eroding, supplying sediment to the basins from the interior. Beginning in the Ordovician Period, mountain building intermittently proceeded in the eastern part of the Appalachian region throughout the rest of the era, bringing in new sediments. Sediments washing from the Acadian Mountains filled the western part of the Appalachian basins to form the famous coal swamps of the Carboniferous Period.

Paleoclimatic studies and evidence of glaciers indicate that central Africa was most likely in the polar regions during the early Paleozoic. During the early Paleozoic, the huge continent Gondwanaland had either formed or was forming. By mid-Paleozoic, the collision of North America and Europe produced the Acadian-Caledonian uplifts, and a subduction plate uplifted eastern Australia. By the late Paleozoic, continental collisions formed the supercontinent Pangaea and resulted in some of the great mountain chains, including the Appalachians, Urals, and mountains of Tasmania.

Tectonic activity[link]

Land distribution early in the Paleozoic, around 500 Ma

Geologically, the Paleozoic starts shortly after the breakup of a supercontinent called Pannotia and at the end of the global Varanger glaciation and Snowball Earth. Throughout the early Paleozoic, the Earth's landmass was broken up into a substantial number of continents. Towards the end of the era, the continents gathered together into a supercontinent called Pangaea, which included most of the Earth's land area.

Climate[link]

The Ordovician and Silurian periods were warm greenhouse periods, with the highest sea levels of the Paleozoic (200 m above today's); the warm climate was interrupted only by a ~30 Ma cool period, the Early Palaeozoic Icehouse, culminating in the Hirnantian glaciation.^[3]

The early Cambrian climate was probably moderate at first, becoming warmer over the course of the Cambrian, as the second-greatest sustained sea level rise in the Phanerozoic got underway. However, as if to offset this trend, Gondwana moved south with considerable speed, so that, in Ordovician time, most of West Gondwana (Africa and South America) lay directly over the South Pole. The early Paleozoic climate was also strongly zonal, with the result that the "climate", in an abstract sense became warmer, but the living space of most organisms of the time—the continental shelf marine environment—became steadily colder. However, Baltica (Northern Europe and Russia) and Laurentia (eastern North America and Greenland) remained in the tropical zone, while China and Australia lay in waters which were at least temperate. The Early Paleozoic ended, rather abruptly, with the short, but apparently severe, late Ordovician ice age. This cold spell caused the second-greatest mass extinction of Phanerozoic time. Over time, the warmer weather moved into the Paleozoic Era.

The middle Paleozoic was a time of considerable stability. Sea levels had dropped coincident with the ice age, but slowly recovered over the course of the Silurian and Devonian. The slow merger of Baltica and Laurentia, and the northward movement of bits and pieces of Gondwana created numerous new regions of relatively warm, shallow sea floor. As plants took hold on the continental margins, oxygen levels increased and carbon dioxide dropped, although much less dramatically. The north–south temperature gradient also seems to have moderated, or metazoan life simply became hardier, or both. At any event, the far southern continental margins of Antarctica and West Gondwana became increasingly less barren. The Devonian ended with a series of turnover pulses which killed off much of Middle Paleozoic vertebrate life, without noticeably reducing species diversity overall.

The late Paleozoic was a time which has left us a good many unanswered questions. The Mississippian began with a spike in atmospheric oxygen, while carbon dioxide plummeted to unheard-of lows. This destabilized the climate and led to one, and perhaps two, ice ages during the Carboniferous. These were far more severe than the brief Late Ordovician Ice; but, this time, the effects on world biota were inconsequential. By the Cisuralian, both oxygen and carbon dioxide had recovered to more normal levels. On the other hand, the assembly of Pangea created huge arid inland areas subject to temperature extremes. The Lopingian is associated with falling sea levels, increased carbon dioxide and general climatic deterioration, culminating in the devastation of the Permian extinction.

Flora[link]

Early land plants

While macroscopic plant life appeared early in the Paleozoic and possibly late in the Neoproterozoic, it mostly remained aquatic until sometime in the Silurian and Devonian, when it began to transition onto dry land. Terrestrial flora reached its climax in the Carboniferous, when towering lycopsid rainforests dominated the tropical belt of Euramerica. Climate change caused the Carboniferous Rainforest Collapse which fragmented this habitat, diminishing the diversity of plant life in the late Carboniferous and Permian.^[4]

Fauna[link]

A noteworthy feature of Paleozoic life is the sudden appearance of nearly all of the invertebrate animal phyla in great abundance at the beginning of the Cambrian. The first vertebrates appeared in the form of primitive fish, which greatly diversified in the Silurian and Devonian. The first animals to venture onto dry land were the arthropods. Some fish had lungs and strong, bony fins and could crawl onto the land also. The bones in their fins eventually evolved into legs and they became the first tetrapods. Amphibians were the dominant tetrapods until the mid-Carboniferous, when climate change greatly reduced their diversity. Later, reptiles prospered and continued to increase in number and variety by the late Permian.^[4]

See also[link]

Wikimedia Commons has media related to: Paleozoic

• Geologic timescale
• Precambrian
• Cenozoic
• Mesozoic

References and further reading[link]

• British Palaeozoic Fossils, 1975, The Natural History Museum, London.
• "International Commission on Stratigraphy (ICS)". Home Page. http://www.stratigraphy.org/. Retrieved September 19, 2005. 

External links[link]

• 60+ images of Paleozoic Foraminifera

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Zdeněk Michael František Burian (February 11, 1905, Kopřivnice, Moravia - July 1, 1981 Prague) was a Czech painter and book illustrator whose work played a central role in the development of palaeontological reconstructions during a remarkable career spanning five decades. Originally recognised only in his native Czechoslovakia, Burian's fame later spread to an international audience, and a number of artists later attempted to emulate his style. He is regarded by many as the most influential palaeo-artist of the modern era.

Introduction[link]

Burian was an extremely prolific artist whose works are estimated to number between 15,000 and 20,000 paintings and drawings (pen and pencil). He illustrated over 500 books (including natural history subjects and numerous classic novels such as Robinson Crusoe, Tarzan, Plutonia) and some 600 book covers, but it is within the fields of palaeontology and palaeoanthropology that Burian's influence has been most notable. Since the late 1950s and early 1960s when Burian's work became known in the west through a series of large-format books released by the Artia publishing house, numerous scholarly and popular books on prehistoric life have featured his work, either as originals or as art based closely on them.

Early career and influence on palaeontology[link]

Burian worked in initial cooperation with university palaeontologist Josef Augusta from 1938/39 (during World War II all universities in Czechoslovakia were closed due to the German occupation) and subsequently (following Augusta's death in 1968) with Zdeněk Špinar, painting accurate and magnificent reconstructions representing all forms of prehistoric life from many parts of the globe, from the earliest invertebrates to a vast array of fish, amphibians, reptiles, mammals and birds, as well as panoramic vistas of the landscapes in which they lived. Close to 500 prehistoric images were painted by him between the early 1930s and the late 1970s.

Whilst some of Burian's earliest palaeo works depicting North American species were inspired by the pioneering American palaeo-artist Charles R. Knight (see for example, his first renditions of Stegosaurus and Brontotherium), partly because Burian lacked access to skeletal material for such reconstructions, Burian's work was less stylised and more convincing with respect to both the subjects and their landscapes, and soon became highly regarded amongst palaeontologists, especially in Europe. Previous palaeo-artists had often produced speculative works reflecting 19th century views of large dinosaurs as lethargic reptiles akin to giant lizards with sprawling limbs, but Burian convincingly painted them as active animals with parasagittal (mammal or bird-like) limb-movement and musculature.

Burian depicted the American sauropods Apatosaurus (1940), Diplodocus (1952 & 1965?), and Barosaurus walking on land in elephantine fashion, and his 1941 reconstruction of the East African sauropod Brachiosaurus (the only image showing the main subject in water) became one of the most reproduced dinosaur images in history. Although it is now considered unlikely that Brachiosaurus could have inhaled in deep water (unless it had a strengthened pleural cavity as do some whales), the reconstruction is remarkably realistic and was still being reproduced 60 years after it was painted.

As with many of his works, Burian's sauropod reconstructions reached iconic status, with the celebrated palaeontologist William Elgin Swinton (1900–1994) noting: "The ideas as well as the pictorially beautiful restorations of Zdenek Burian, done under the direction of the late Joseph Augusta (1962), create a lasting impression that appears to be decisive. The Czechoslovakian experts have placed us all in their debt and the life-restorations of Brontosaurus, Diplodocus and Brachiosaurus provide debating points as well as aesthetic satisfaction" (The Dinosaurs, 1970: 189).

Another famous Burian painting (dated 1938) shows the dynamism of his work with a Tyrannosaurus Rex rushing to attack one of a pair of startled duck-billed Trachodon as fleet-footed ornithomimids bound off in the distance. Following subsequent palaeontological evidence, the predator was later modified by adding skull protuberances and a stiffer tail. This painting is one of his few works that show dinosaurs in direct conflict.

Many of Burian's early paintings appeared in a series of large format books with text by Augusta, the first of which, Prehistoric Animals, was originally published in Czechoslovakia by Artia (1956) and later in many other countries including Italy, France, Germany, England and Japan. The late S.J. Gould, who was an enthusiast of the work of Charles R. Knight, described it as one of the 20th Century's three most influential visual books on prehistory (many would suggest that it was the most influential), and it was followed by a series of other landmark titles: Prehistoric Birds & Reptiles, Prehistoric Sea Monsters, The Book of Mammoths, and Prehistoric Man, all of which became famous and collectable in their own right. The influence of Burian's work is clearly discernible in many later films depicting dinosaurs and other prehistoric animals, right up to the Jurassic Park series.

Partial bibliography[link]

• Life before Man Zdeněk V. Špinar, illustrated by Burian. Prague: Artia, 1972. Reprinted by Crescent Books, 1981. ISBN 0-517-34722-9

Artistic style[link]

Although Burian's reconstructions of extinct life are very convincing, his often-reproduced dinosaur reconstructions were all the more remarkable in that he did not have access to skeletal material, but rather depended largely on drawings and photographs provided by his collaborators Augusta and Špinar (although Czechoslovakia had a notable history of palaeontological research, it lacked dinosaur fossils). In many cases, he undertook anatomical reconstructions of his subjects before depicting life restorations, and sometimes painted more than one version of an animal (particularly if the first version had been painted in b&w), examples being Dimetrodon, Tylosaurus, Brachiosaurus, Diplodocus, Stegosaurus, Brontotherium, Arsinoitherium, Phororhacos, Archaeopteryx amongst others.

Many of Burian's early works were accompanied by text from Augusta (often in an almost story-book fashion) and it is within this context that Burian produced his most memorable and famous works which were used as educational aids in schools across Czechoslovakia to show the succession of life on Earth. His style reflected a classic, almost romantic imagery that rarely showed animals fighting or preying on each other (some paintings did show carnivores with their prey, but generally either before the confrontation or after it had been dispatched). Two years after Augusta's death, Burian painted what is regarded as his last classic image, the famous 'heroic' Tarbosaurus bataar of Mongolia (an image that was also widely reproduced and copied).

Following Augusta's death, conditions were increasingly placed on Burian's artistic licence and the scientific detail of what he painted, whilst he was also being asked to depict different species within the same scenes but as individual, non-interacting animals as in a montage. Given his background as a novel/action-scene illustrator, and the close collaboration with Augusta the 'story-teller', Burian viewed the subjects of his paintings as very real animals (as would a natural history artist), and the new restrictions did not sit well with him. An example of how his work was compromised is evident in another version of Brachiosaurus that he painted in his later years under the direction of Vratislav Mazak; the animal, now shown on dry land, appears oddly out of proportion and fails to compare to the 1941 version. In his later years, Burian was in demand by publishers requesting bland, catalogue-like stand-alone prehistoric animal images as illustrations for reference books, a style that Burian neither favoured nor excelled at.

Burian's works, which vary in size from A4 to several square metres, were mostly executed in oils, both in colour and black and white, and exhibit keen attention to detail and unmistakable realism whilst maintaining a strong sense of atmosphere. Whilst his style was very traditional, it was combined with a dynamism that represented a break with the often staid palaeo-reconstructions of previous artists. A feature of many of the paintings, and one that is missing from the work of other palaeo artists, is the realistic effect of movement and action which was achieved not only by the dynamic positions of the subjects, but by a clever blurring of the edges of moving objects (such as the tips of waves or palm fronds in the wind) to produce a clever effect of photo-realism. It has often been noted that Burian's renditions appear to have been painted from life, so close is the perceived association between the subject and its environment. This is perhaps not surprising given that Burian was already well accomplished at painting natural history subjects before he began painting prehistoric scenes.

Memorial plaque of Zdeněk Burian in Kopřivnice

Legacy[link]

Many Burian paintings have become celebrated images of palaeontology and palaeoanthropology, especially the frequently reproduced images of Mesozoic reptiles (pterosaurs, dinosaurs, mosasaurs and plesiosaurs) whilst his evocative depictions of proboscideans, Ice Age mammals, and a remarkable series of paintings of early hominids through to modern man are without equal. He also painted extant native peoples of the world, including those of Africa, South America and the South Pacific. Original Burian paintings are on exhibit at Dvůr Králové Zoo (especially his large oil canvas), at the National Museum (Prague) and at the Anthropos Museum in Brno (particularly his anthropological reconstructions).

Initially released by Czech publishers followed by western publishers Paul Hamlyn and Thames & Hudson with translated texts, Burian's work was later widely reproduced (often as teaching material) by European and American authors (including Edwin Colbert). Images based on his paintings have featured on postage stamps issued by many countries, and the pioneering director/animator Karel Zeman used Burian paintings to produce models and 2-D animated images for his 1955 landmark feature film Cesta do pravěku (released in the US as Journey to the Beginning of Time).

Burian's work has probably inspired more imitators in the field of palae-reconstruction than any other artist, and his prehistoric paintings have frequently been copied, and not always with acknowledgement. A notable case is A New Look at the Dinosaurs, by Alan J. Charig (1979), British Museum Natural History, which featured thinly-disguised ink copies of Burian paintings that were inversed as mirror images. Another example is the many Adèle Blanc-sec comic strips which depict dinosaurs closely resembling Burian's work (e.g. the Tarbosaurus [tome 2] and the pterodactyl of 'Adèle and the Beast').

The 1992 video game Ecco the Dolphin features in-game artwork inspired by Burian and recreated in pixels by Zsolt Balogh.

External links[link]

• Gallery of 31 paintings with descriptions (Russian)
• Gallery of 152 paintings (Russian)
• Gallery of 60 paintings (Russian)
• Zdenek Burian Museum (Czech)
• Zdenek Burian memorabilia