About 270 million years ago, during the Permian Period, shallows seas covered many spaces that have since become dry land. Here, in a sea overlaying present-day Texas, invertebrates including brachiopods, bryozoans, sponges and microbial mats dominate a reef scene. Ocean life at this time was diverse–until a mass extinction at the end of this period wiped out animals both on land and in the seas, including some 90% of marine invertebrates.
This diorama is located in the Museum’s Hall of Ocean Life.
This is the artwork of famed 19th century German biologist and naturalist Ernst Haeckel who produced the colorful masterpiece “Art Forms of Nature”. All the plates in the work depict the diversity of form within certain animal groups. This one is of the Blastoidea, a class within Phylum Echinodermata that includes crinoids, starfish, brittle stars, sea urchins and sand dollars, among others. Blastoids likely appeared late in the Cambrian or early Ordovician almost 500 million years ago, and met extinction during the great dying at the end of the Permian Period, some 250 million years ago. They left a prolific fossil record due to the relatively easy preservation of their calcified protective outer plates.
Earth’s greatest extinction event happened in a one-two punch 252
million years ago. Research now suggests that the second pulse of
extinction, during which nearly all marine species vanished from the
planet, happened in the wake of huge volcanic eruptions that spewed out
carbon dioxide and made the oceans more acidic.
The work, published in Science1,
is the latest to try to pinpoint the causes of the ‘Great Dying’, at
the end of the Permian period. The study uses chemical evidence in rocks
from that period to calculate how quickly ocean chemistry shifted.
Clarkson, M. O. et al. Science 348, 229–232 (2015).
Trilobites survived for roughly 270 million years before disappearing at the end of the Permian period. Florilegius/SSPL/Getty
Today, we look at one of the last trilobites to exist, Ameura major, a 3 cm-long specimen collected in Missouri. This species lived approximately 260 million years ago, near the end of the Permian, the last period of the Paleozoic era. The end of the Permian signaled the end of trilobites, along with approximately 80 percent of life on earth. That event stands as the largest mass extinction in the history of our planet, even more severe than the mass extinction that some 200 million years later, would eradicate non-avian dinosaurs.
To date all of the known pareiasaurs who roved the supercontinent of
Pangea in the Permian Period a quarter of a billion years ago were
sprawlers whose limbs would jut out from the side of the body and then
continue out or slant down from the elbow (like some modern lizards).
Morgan Turner, lead author of the study in the Journal of Vertebrate
Paleontology, expected Bunostegos would be a sprawler, too, but the
bones of the animal’s forelimbs tell a different story…
Here is a remarkable, museum quality plate containing two fossil Discosauriscus austriacus. Discosauricus was a small seymouriamorph that lived in Central Europe during the Lower Permian Period. Many seymouriamorphs were terrestrial or semi-aquatic. However, aquatic larvae bearing external gills and grooves from the lateral line system have been found, making them unquestionably amphibians. The adults were terrestrial.
Inhabiting the lakes and rivers of Victoria, Australia during the Cretaceous was an amphibian the size of a saltwater crocodile, growing up to 5 metres in length (from nose to tail), with an enormous jaw one metre in diameter weighing half a tonne. With eyes on the top of its shovel-like head, grooved teeth and relatively small limbs, Koolasuchus was most likely an aquatic ambush predator, feeding on crustaceans, molluscs, fish and turtle, able to locate its prey by detecting their vibrations in the water. We know from highly ornamented surfaces on the cranium that Koolasuchus had a highly developed sensory line system, used to detect movement and vibration in the surrounding water.
… is an extinct genus of synapsid that lived from about 300 to about 280 million years ago (Ma) during the Late Carboniferous and Early Permian periods. Like the closely related Dimetrodon, Sphenacodon was a carnivorous member of the Eupelycosauria family Sphenacodontidae. However, Sphenacodon
had a low crest along its back, formed from blade-like bones on its
vertebrae (neural spines) instead of the tall dorsal sail found in Dimetrodon. Fossils of Sphenacodon are known from New Mexico and the Utah-Arizona border region in North America.
It is narrow from side to side and vertically deep, with an indented
notch at the front of the maxillary bone in the upper jaw. The upper and
lower jaws are equipped with an array of powerful teeth, divided into
sharp pointed “incisors” [precaniniforms], large stabbing “canines”
[caniniforms], and smaller slicing back teeth [postcaniniforms]. The
orbit is set high and far back with a single opening (temporal fenestra)
behind and partly below the eye, a characteristic of synapsids…
An elegant choice for #FossilFriday! These beautiful crinoidea, or sea lilies, were echinoderms like starfish and sea urchins. They were pseudoplanktonic filter feeders, made up of a calcareous stalk at the end of which were flexible arms, which caught algae, unicellular organisms, small crustaceans and the larvae of invertebrates floating in the water.
Fossilized species, such as the Seirocrinus subangularis, formed in abundance in “meadows” on the seabed. Having appeared in the Cambrian period, they were badly affected by the most significant mass extinction that earth has ever seen. Almost 95% of marine species and 70% of terrestrial species disappeared at the end of the Permian period, 250 million years ago.
Crinoids similar to these fossils still cover tropical seabeds today. They were believed to be extinct for a long time – in fact, these modern species were only identified after the discovery of their fossilized ancestors!
Many millions of years ago in the Permian geologic period (approximately 298-252 Ma), an extensive inland sea encroached onto the North American continent from the south, spreading from what is now the Gulf of Mexico up to Canada.
Ouranosaurus was a famous iguanodont from the Aptian age of the Early Cretaceous, about 125 to 112 million years ago. It was found in multiple locations, with two complete fossils in the Echkar Formation, Gadoufaoua deposits in Agadez, Niger. It was about 7 to 8 meters long, with its head about 2 meters high and the sail over 3 meters high from the ground. It was an herbivore, with a large sail on its back supported by long, wide spines on the entire back and tail like that of Spinosaurus, which did not resemble the spines of the synapsid Dimetrodon from the Permian period. The spines in Ouranosaurus, unlike Dimetrodon, become thicker as you go down the back and flatten up. There were also tendons that strengthened the back, and the spine length peaks over the arms, rather than the legs. Its front limbs were fairly long, about 55% of the length of the hindlimbs, indicating that it could have walked quadrupedally. It had a thumb claw, like Iguanodon, and the rest of its fingers were similar to hooves, good for walking. Its fifth finger, unlike in other Iguanodonts, was not prehensile. Its hindelimbs were large and bulky to allow for bipedalism and it was not built for sprinting, and nor was it a good runner.
It had a long snout for an Iguanodont, with a large batteries of teeth allowing for chewing of food. It had weak jaw muscles, but had a diet mainly of leaves, fruit, and seeds, getting more energy from it due to chewing. It lived in a river delta area, fairly wet and swampy unlike the area today. It probably came into contact with Suchomimus, especially since bones of a juvenile Iguanodon were found in the stomach of Baryonyx in England, and thus it is not unreasonable that spinosaurids were versatile predators, feeding on both fish and the Iguanodonts of the time. It also lived alongside Carcharodontosaurus which would have fed on it, as well as the crocodile Sarcosuchus.
Sometimes, a name just fits. Casea was a low-slung, slow-moving, fat-bellied pelycosaur
that looked just like its moniker–which is Greek for “cheese.” The
explanation for this reptile’s strange build was that it had to pack
digestive equipment lengthy enough to process the tough vegetation of
the late Permian period into a limited amount of trunk space.
In most regards, Casea looked virtually identical to its more famous cousin Edaphosaurus, except for the lack of a sporty-looking sail on its back (which may have been a sexually selected characteristic).
A little-known mass extinction may have killed up to about 80 percent
of all vertebrates on land about 260 million years ago, researchers say.
This catastrophic die-off coincided with the onset of volcanism in what
is now southern China, which suggests a cause for this calamity, the
The history of life on Earth is ominously interrupted by mass extinctions. Over the past 500 million years, five mass extinctions — at times called “The Big Five”
— are each thought to have annihilated anywhere from 50 to 95 percent
of all species on the planet.
For two decades, scientists have proposed that another mass extinction
struck Earth about 260 million years ago, at the end of the Capitanian
stage at the Guadalupian epoch in the middle of the Permian period.
Previous estimates suggested this crisis, known as the end-Capitanian,
end-Guadalupian or mid-Permian mass extinction, eliminated at least 56
percent of land plant species and about 58 percent of all marine
invertebrate genuses. ..
A nocturnal existence is a way of life for numerous mammals, from bats that swoop through dark skies to skunks that emit their noxious spray under moonlight and majestic lions, tigers and leopards that prowl the night.
But this love of nightlife appears to have begun much earlier than previously believed in the lineage that led to mammals - perhaps 300 million years ago - way before the first true mammals skittered under the feet of the dinosaurs about 100 million years later.
Scientists on Wednesday said a study of fossils of small ring-shaped bones embedded in the eyes of an important group of ancient mammal relatives called synapsids indicated that many of them thrived at night or in the twilight.
The findings appear in the journal Proceedings of the Royal Society B.
The mammal relatives arose around 320 million years ago and became the dominant land creatures during the Permian Period that preceded the rise of the dinosaurs in the Triassic Period that followed. They prospered worldwide, with plant and meat-eating beasts.
“The study does give us new insights into the daily lives of some of our most ancient relatives,” said Kenneth Angielczyk, a paleontologist with the Field Museum of Natural History in Chicago.
The findings indicate nocturnal activity has a deep history in the lineage leading to mammals. This contradicts the conventional wisdom that the nocturnal lifestyle emerged with the appearance of the first bona fide mammals about 200 million years ago because they needed to slink around in the dark to avoid becoming dinosaur chow.
The researchers focused on bones called scleral ossicles that reveal the eye’s dimensions and enable predictions about light sensitivity, indicating whether an animal was nocturnal or active during daytime or active in twilight conditions. Modern mammals lack these bones.
The researchers scoured museum collections around the world and found 38 specimens comprising 24 species, mostly from the United States and South Africa but also from Russia and Brazil.
“Specimens with well-preserved scleral rings are rare, so it took a lot of searching,” Angielczyk said.
Researchers found that the eyes of ancient synapsids likely spanned a range of light sensitivities, some suited to nighttime and others favoring daylight. The oldest synapsids possessed eye dimensions consistent with night activity. Predators were more likely than herbivores to be nocturnal.
One of the best known and oldest of the ancient synapsids is Dimetrodon, a sharp-toothed, 11-foot-long (3.5 meters), four-legged predator whose back was topped by a remarkable semicircular sail-like structure. The study found Dimetrodon probably was nocturnal, hunting at night like many big cats today.
“Nocturnality comes with advantages and disadvantages,” said another of the researchers, Lars Schmitz, a biology professor at Claremont McKenna, Pitzer and Scripps Colleges in California.
“It’s cooler at night, which may be beneficial for some species. As a hunter, it may be easier to approach prey. On the other hand, the dim light levels make it difficult for animals. Keen senses are beneficial,” Schmitz added.
(Reporting by Will Dunham; Editing by Leslie Adler)
Ophiderpeton was an amphibian from the Viséan age of the Mississippian epoch of the Carboniferous to the Sakmarian age of the Cisuralian epoch of the Permian period, about 345.3 to 294.6 million years ago. It was very snake like, without any traces of limbs, and was about 70 centimeters long. However, it was not a snake, but an “amphibian,” aka, a non-amniotic (meaning, it did not belong to the group containing mammals and reptiles) tetrapod (land dwelling vertebrate). There are a lot of conflicting hypotheses on how “Amphibians” should be classified and, as such, it’s hard to classify any of them. It lived in Ohio as well as the Czech Republic, and it would have been a hunter, feeding on worms, insects, millipedes, and snails.
Phylum : Chordata Class : Synapsida Order : Therapsida Infraorder : Dicynodontia Family : Pylaecephalidae Genus : Diictodon Species : D. feliceps, D. galeops, D. grimbeeki, D. ictidops, D. palustris, D. psittacops, D. parringtoni
As a therapsid, Diictodon shared many features with modern day mammals. Most noticeably, they made burrows into the earth. These burrows could be up to 1.5 m deep. Many scientists believe that Diictodon lived like the modern gopher. These could have been used to escape the heat of the desert, which was the dominant environment on the continent of Pangaea in the Late Permian Period. Inside these burrows, nests have been found, where Diictodon skeletons are present. They were social and gregarious, and lived together, with numerous burrows in 500 square meters of space. However, their burrows were unconnected and did not form any large colonies. Many Diictodon nested close to flood plains, and some specimens may have been killed as water flowed into the nests, drowning the animals. Diictodon had no known rival species competing in its niche, so they may have competed primarily with others of their species for the little plant material available.
Like all dicynodonts, Diictodon were herbivorous. They used their beaks to break off pieces of the sparse desert shrubs. Like modern desert animals, Diictodon may have had unusually efficient digestive systems, due to the lack of nutrients present in desert plants. As burrowing animals, they may have fed off of water-rich plant tubers (roots).
Gorgonops was a therapsid reptile living around 250 million years ago, towards the end of the Permian period. About the size of rhino at around 2 metres but with a leaner, sleeker body, Gorgonops was agile and the apex predator of its time. Their acute eyesight and powerful sense of smell, not to mention fangs that could reach up to 15cm long meant Gorgonops would’ve been capable to bring down prey larger than itself. Its teeth were long and curved, this predatory design reappeared through the ages, also being seen in the sabre tooth cats of the Cenozoic era.
The late Permian is synonymous for extinction, where many animals perished in a harsh world with little rainfall, endless deserts and scorching temperature, but theraspids including Gorgonops, thrived. It had long, upright legs which allowed them to run and walk with ease in the heat, and it probably hunted in the early morning and rested in the afternoon heat, like many animals today.
Therapsids mat have looked like a distant relative dinosaur, but they were more closely related to mammals. They were an important group of animals because although they were reptiles as they were cold blooded, they also had mammalian traits such as legs tucked under the body and teeth that were capable of tearing into a variety of foods. The first true mammals would evolve from therapsids. Gorgonopsid fossils have been found globally, yet Gorgonops is known only from specimens found in South Africa. Varieties of gorgonopsid look similar but some could be the size of a dog, where others grew much larger. Gogonops was one of the first species of therapsid to be identified by Richard Owen, the man responsible for coining the term “dinosauria”. Despite their dominance and ability to survive in a dying world, Gorgonops would not make it through the Permian extinction, which claimed the prey and then the hunters, including Gorgonops.