Machairodus

The genus Machairodus is a little fuzzy on the species that it actually contains. Because the fossil record is incomplete, different extinct big cat species have been moved both in, and out of the genus. It also doesn't help that some of the species have been reclassified, combined, or moved to subspecies status... but such is the finicky nature of fossils!

At any rate, Machairodus refers to a group of very large cats, all of whom lived in North America between about 11 million, and 120,000 years ago.

These cats were of the "saber-toothed" variety, possessing long, thin, knife-like canine teeth. Those teeth, combined with their short legs, meant that they probably hunted by ambushing prey, rather than by chasing it down. Machairodus species are often draft with spots or stripes, since that coat pattern would've served them well as camouflage during their ambush hunts.

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Status : Extinct, lived 11.6 million to 124,000 years ago
Location : North America
Size : Length up to 8ft (2.5m)
Classification : Phylum : Chordata -- Class : Mammalia -- Order : Carnivora
Family : Felidae -- Genus : †Machairodus
Image : Carnivora

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Pteranodon

Pteranodon longiceps

There have been dozens of different Pterosaurs discovered, and today's animal is one of the best well known. In fact, it is the "type species" for the genus. This means that when you hear the term "Pteranodon," it refers to not just the genus that contains several difficult species, but also to a single specific species -- Pteranodon longiceps.

This large flying Reptile (Pterasaurs are not Dinosaurs) lived between 85 and 75 million years ago, and its fossils have been found in both Europe and North America. It was first discovered in Kansas back in 1876 by Othniel Charles Marsh, and many hundreds of fossils have since been found at and around that Kansas site.

Pteranodon had a massive wingspan-- most fossils show a spread of 20ft or more! Like modern birds, Pteranodon had hollow bones that made them light enough to fly. Interestingly, Pteranodon may have had fur!

Pteranodons were Carnivores, even though their beak mouths were missing teeth. Of course, the lack of teeth doesn't stop modern birds, so why would a 75 million year old Reptile be any different? Pteranodons captured sea creatures that swam near the surface of the water, and may have swallowed them whole.

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Status : Extinct, lived 85-75 million years ago
Location : Europe, North America
Size : Wingspan up to 20ft (6m)
Classification : Phylum : Chordata -- Order : †Pterosauria -- Family : †Pteranodontidae
Genus : †Pteranodon -- Species :  P. longiceps
Image : Heinrich Harder, Andre Engels

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Puijila darwini

Though it may not look like it, the animal in that picture-reconstruction is an ancestral Seal! Yes, Seal! The finned, sleek bodied ocean mammals! In fact, it is the most ancient Seal ever found.

Puijila darwini was only discovered in 2007, so it is a pretty recent find. Amazingly, only one fossil has been uncovered so far-- but the skeleton was almost totally complete! It was found in Nunavut, Canada.

Puijila lived a semi-aquatic carnivorous lifestyle. It had webbing on all four feet, and swam by paddling through the water. It is an interesting fossils not just because it is the most primitive Seal known, but also because it is an example of a transitional species. All land animals evolved from sea-dwelling creatures, and Seals and Whales are examples of mammals that returned to the sea. Puijila was a step between fully land-dwelling Carnivore and the eventual ocean-dwelling Pinnepeds.

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Status : Extinct, lived 21-24 million years ago
Location : Canada
Size : Length up to 3.3ft (1m)
Classification : Phylum : Chordata -- Class : Mammalia -- Order : Carnivora
Suborder : Pinnipedimorpha -- Genus : Puijila -- Species : P. darwini
Image : Smokeybjb

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Charonosaurus

Charonosaurus is one many different Hadrosaur, or "Duck-Billed" species. It was discovered relatively recently, with the first fossils uncovered in 2000.

Charonosaurus is named for Charon of Greek Myth, the ferryman who carried souls across the river Styx. The Fossils were found on the banks of a river, inspiring the name. They lived between 67 and 65 million years ago, going extinct during the event at the end of the Cretaceous.

Only a few bones have been found of this Dinosaur-- most notably a partial skull. Though we don't have a full skeleton, we can use ratios found in relative Hardosaurs and determine Charonosaurus's size. They were one of the largest members of their family, and could grow as long as 33, possibly 40 feet!

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Status : Extinct, Lived 67-65 million years ago
Location : China and Russia
Size : Length up to 33ft (10m)
Classification : Phylum : Chordata -- Clade : Dinosauria -- Order : †Ornithischia
Family : †Hadrosauridae -- Genus : †Charonosaurus -- Species : † C. jiayinensis
Image : Carnivora Forum

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Anomalocaris

Anomalocaris

Anomalocaris is the name of a genus that lived during the Cambrian period... over half a billion years ago!

These ancient relatives to the arthropods of old swam in the seas that covered the planet. Their fossils have been found in places that are (now) as far apart as Canada, China, and Australia.

Anomalocaris grew up to 3ft in length, and had a segmented body that allowed it to swim using an undulating motion. They also had complex, stalked eyes, and two arms covered in barbs that extended from the mouth. The mouth itself was circular, and may have been able to crush hard-bodied prey like Trilobites.

The interesting anatomical features of Anomalocaris made it difficult to identify for many, many years. Different body parts were found independent from one another, and were actually attributed to several different animals, including Jellyfish and Crustaceans. While the first fossils were discovered in 1892, it took until 1985 for scientists to realize all of those fossils belonged to the same animal!

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Status : Extinct, lived during the Cambrian ~500 million years ago
Location : Worldwide
Size : Length up to 1m
Classification : Class : †Dinocaridida -- Order : †Radiodonta
Family : †Anomalocarididae -- Genus : †Anomalocaris
Images : Worldlesstech

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Triceratops

Triceratops is one of those iconic Dinosaurs, everyone recognizes it! These four-legged herbivores were discovered by Othniel Charles Marsh during the famous late 19th century "Bone Wars," and their fossils have been found in various deposits in western North America.

Triceratops

Triceratops is a genus name that encompasses three different species, with Triceratops horridus being the most well known. They measured as long as 30 feet from nose to tail tip, and could weigh well over 20,000lbs.

These Dinosaurs were named for the three horns on their skulls. These horns, and the large bony neck frill behind them, were probably used for defense. And Triceratops certainly had a lot to defend against-- these guys lived at the end of the Cretaceous, in about the same time and place that T. Rex and other very large, very powerful predators lived!

Aside from defense, the horns and neck frill may have served a purpose in during mating season. The neck may have even helped to regulate body heat!

Triceratops lived up until the very end of the Cretaceous, and died out along with all of the other Dinosaurs that were around for the K-T Extinction Event.

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Status : Extinct. Lived 72-65 million years ago
Location : North America
Size : Length up to 30ft (9m), Weight up to 26,000lbs (12 tonnes)
Classification : Phylum : Chordata -- Order : †Ornithischia
Family : †Ceratopsidae -- Genus : †Triceratops
Image : Nobu Tamura , Minnesota Jones

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Sardinian Pika

Prolagus sardus

The Sardinian Pika was one of a kind-- the only member of its genus to survive till modern times. These cousins to the modern Pikas (themselves relatives to Rabbits and Hares, not rodents) lived on the islands of Sardinia and Corsica before they went extinct in the late 1700s.

Written accounts and fossil remains show that the Sardinian Pikas were once abundant on their home islands. They were hunted by the peoples that arrived there around 6,000 years ago, and may have been considered a delicacy.

Unfortunately, these Lagomorphs are no more. Many factors contributed to their decline-- the introduction of dogs and foxes and increase human populations among them. The exact date of extinction is unknown, but it was some time at the end of the 18th or the beginning of the 19th century.

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IUCN Status : Extinct
Location : Sardinia, Corsica
Size : Length up to 10in (25cm)
Classification : Phylum : Chordata -- Class : Mammalia -- Order : Lagomorpha
Family : Prolagidae -- Genus : Prolagus-- Species : P. sardus
Image : Animal Photo Album

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Obdurodon tharalkooschild

Obdurodon tharalkooschild

Some newly discovered fossils have been all the rage this week-- gigantic extinct Platypus! The modern Platypus is a strange enough creature, but this prehistoric version takes it to a new level!

As you may know, the Platypus is one of only a handful of living Monotremes-- primative mammals that lay eggs. It was long believed that the Platypus had a very direct evolutionary story, one with very minimal branches. Obdurodon tharalkooschild, which was found in North-west Queensland (an area absent of modern Platypuses) was over a meter long and had teeth.

In fact, it was the fossilized tooth that put this whole story together. Modern Platypuses have teeth only as infants. They lose them as they grow up and they are never replaced. O. tharalkooschild had incredbily large teeth that it kept it's entire life. It had a carnivorous diet and could've used its giant chompers to feed on turtles and lungfish.

A few other extinct Platypuses have been discovered over the years, but all had smaller, and fewer teeth as they got chronologically closer to the present. O. tharalkooschild, which lived between 15 adn 5 million years ago, bucks that trend, which is why scientists believe it was part of a different Platypus evolution branch!

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Status : Extinct, lived 15m-5m years ago
Location : Australia
Size : Length up to 3.3ft (1m)
Classification : Phylum : Chordata -- Class : Mammalia -- Order : Monotremata
Family : Ornithorhynchidae -- Genus : †Obdurodon -- Species : O. tharalkooschild
Image :  Peter Schouten

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Toxodon

Toxodon

A couple million years ago there were all sorts of gigantic mammals living in North and South America, including the Toxodon. This beat, which weighed over 3000lbs, and measured up to 9ft in length, inhabited the South American plains until about 10,000 years ago.

From its skeleton you might think that Toxodon was a Rhinoceros. But such is not the case. Amazingly, Toxodon belonged to a now completely extinct order called Notoungulata. All animals in that Order are examples of convergent evolution-- they looked and behaved the same as other creatures that they weren't related to at all!

Even though Toxodon and modern Rhinos weren't related, they still had a lot in common. They were very large, they had stout, powerful bodies, and they feed on leaves and other plants. Toxodon was even hunted by humans. Several fossils have been found with arrowheads in the vicinity, proving that these animals were prey for early humans. Hunting may have also played a major role in their extinction-- one theory on the decline of Megafauna is that human hunting wiped them all out!

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Status : Extinct, Lived 2.6million to 10,000 years ago
Location : South America
Size : Length up to 9ft (2.7m), Weight up to 3,300lbs (1500kg)

Classification : Phylum : Chordata -- Class : Mammalia -- Order : †Notoungulata
Family : †Toxodontidae -- Genus : †Toxodon

Image : Richard Owen

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Barosaurus

80 different Dinosaurs were discovered by Othniel Charles Marsh during the "Bone Wars" and Barosaurus was one of them.

This relative to the more famous Diplodocus lived during the Upper Jurassic, between 155 and 145 millions years go. Its fossils were first uncovered by Marsh in 1889, and parts have been found in various western American states.

Barosaurus was a very long Dinosaur-- adults could reach more than 80 feet from head to tail, and weight upwards of 40,000lbs. Their necks alone stretched to 30ft! That's almost two giraffes!

The neck of a Barasaurus raises some questions about how this Dinosaur's circulatory system worked. If they held their neck straight up it would require an abnormally massive heart to pump blood all the way to the brain. There are theories that Barosaurus either had secondary heart-like structures in its neck, to help move the blood upwards, or they kept their necks parallel to the ground. However, it is difficult to prove either theory-- soft tissue does not exist for these creatures, and the fossilized vertebrae suggest that the Sauropod did stand with its neck stretching upwards. Either way, very interesting things to think about!

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Status : Extinct 145 million years
Location : North America
Size : Full length up to 85ft (26m), Weight up to 44,000lbs (20 metric tons)

Classification : Phylum : Chordata -- Clade : Dinosauria -- Suborder : †Sauropodomorpha
Family : †Diplodocidae -- Genus : †Barosaurus -- Species : † B. lentus

Image : Debivort, Ryan Somma

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Jeholornis

Jeholornis

Today's animal has been in the news lately, due to a recent discovery relating to its fossils. But mor eon that in a bit. Jeholornis is one of the most ancient birds that we known off-- it lived more than 120 million years ago. Its fossils have been found in China, and were only discovered for the first time back in 2006. (Fun fact: the area where this bird was found is also home to the fossils of many of feathered creatures, including feathered Dinosaurs!)

Jeholornis does not seem to be a direct ancestor of mordern birds-- they come from different lines. However, because of how old this bird is, it can tell us a lot about the early members of the Aves class, and about the evolution of wings and feathers.

Recently, fossils have popped up that suggest Jeholornis had two tails. It was always known that they had a long train of feather, but now there are fossils that show a second tail-- a set of plumage that sticks up from the bird's back.

Scientists can only speculate what the second set of plumes was used for, but use in mating rituals is a good guess. The newly-found tail would jut out similar to the displays done by Peacocks. So far this is the only known bird to have this feather feature!

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Status : Extinct 120 Million Years
Location : China
Size : Total Length up to 2.5ft (80cm)

Classification : Phylum : Chordata -- Class : Aves -- Order : †Jeholornithiformes
Family : †Jeholornithidae -- Genus : †Jeholornis

Image : Aijuan Shi

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Ammonite

Ammonite Model

Ammonite Fossil

Today we are going to talk about an entire Subclass of animals known as Ammonites. These shelled sea creatures lived for millions of years before going extinct along with the Dinosaurs during the late Cretaceous.

Between 240 and 65 million years ago, Ammonites could be found throughout the Oceans of the World. They ranged in size, depending on species, with the largest having shells that could grow as large as 1m in diameter. Ammonite fossils are more abundant than those of just about any other creature, since they lived for so many years and in so many places.

Ammonites lived in schools and hunted smaller sea creatures. They consumed their prey through a beak-like mouth hidden among its tentacles.

Ammonites most likely moved around by shooting water from spouts in their bodies. Their actual lifestyle is pretty speculative though, because unlike other prehistoric invertebrates (like Nautelids), the Ammonites have no living relatives.

A final fun fact to start the weekend? The name Ammonite comes from "Amun," an Egyptian god who was frequently depicted wearing spiraled horns (similar to the shell pattern).

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Status : Extinct for 65 million years
Location : Oceans worldwide
Size : Varies, up to 1m in shell diameter

Classification : Phylum : Mollusca -- Class : Cephalopoda -- Subclass : †Ammonoidea
Images : Lmbuga Commons , Rept0n1x

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Bajaichthys

Bajaichthys elegans

Bajaichthys elegans is known only from a single juvenile fossil that was discovered back in 1987. But the fossil is enough to tell us that this interesting looking creature is a relative to the modern-day Oarfish.

Monte Bolca, near Venice Italy, is the site where the fossil was found. This site is an important trove of fossils from the Eocene, especially the Lutetian Epoch. That time period lasted between roughly 47 and 41 million ago, and it was the same timet hat our buddy Bajaichthys lived.

This creature has quite an interesting look to it-- it has an anal fin that runs the entire length of the tail, a vary tall dorsal fin, and two little wing-like pelvic fins. Because of its anatomy, it could belong to one of two different Lamprid families, which is why is currently does not belong to a family at all! We won't know more until additional, adult forms are uncovered-- which may not happen for a very long time, if at all!

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Status : Extinct 41 million years
Location : Fossils found in Italy
Size : Length of 4cm

Classification : Phylum : Chordata -- Class : Actinopterygii -- Order : Lampriformes
Family: incertae sedis -- Genus : Bajaichthys -- Species : B. elegans

Image : Stanton F Fink

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Paramylodon

Paramylodon harlani

See that skeletal reconstruction? That nearly 10foot tall, monstrously sized creature?

That's a sloth.

An extinct Ground Sloth to be exact. Meet Paramylodon, a distant cousin to the slow tree dwellers we know today. (And by distant... I mean really distant. Their last common ancestor lived about 30 million years ago!)

Paramylodon lived between 5 million and 11,000 years ago, and it's fossils have been found in the United States,  Canada, Mexico, and in Central America. Notable fossils have been found in the La Brea Tar Pits, and many (including those in the image) are on display at the Page Museum there.

One rather interesting fact about Paramylodon is that is had dermal ossicles. This means that they had bony growths under their skin that gave them some extra defense against predators. While there are a few other Ground Sloth species to have that characteristic, it is not common.

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Status : Extinct for 11,000 years
Location : North America
Size : Height up to 9.8ft (3m), Weight up to 2,400lbs (1090kg)

Classification : Phylum : Chordata -- Class : Mammalia -- Order : Pilosa
Family : †Mylodontidae -- Genus : †Paramylodon -- Species : †P. harlani

Image : David Monniaux

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Eurypterus

Eurypterus sp.

The world of the Silurian period was very different from the world of today. Most noticeably, there were no land animals. All of the living animals could be found underwater, populating the oceans that covered many of our present continents.

In these oceans you could find all sorts of primitive life. Bony fish were just starting to make their appearance on the evolutionary timeline, for example. You could also find a massive array of invertebrates, including the members of the genus we'll be learning about today-- Eurypterus.

Eurypterus includes 15 different species of Sea Scorpion, all of whom lived between 432 and 418 million years ago. Their fossils have been uncovered in what is now eastern North America and Europe, and interestingly the first fossils dug up were confused for Catfish bones!

When we think about Scorpions today, we imagine small arachnids that are about the size of your hand. Eurypterus was much, MUCH larger. On average, the different species measured 1-2ft in length. However, the largest fossil showed a creature that was over 4ft long!

Eurypterus had a body made up of two segments-- the prosoma and the opisthosoma. The former contains the head, thorax, and appendages that are used for walked, eating, and swimming. The latter is segmented and contains the gills and reproductive organs.

Members of the genus were opportunistic feeders-- they both hunted and scavenged. While they could swim using their large paddle-like appendages, they did not swim in order to hunt. Eurypterus walked along the sea floor when it was searching for food.

The Eurypterus genus only lasted for 14 million years, which is a short amount of time when compared to other members of its Order. Amazingly though, despite that short amount of time they are the most represented Eurypterids in the fossil record-- nearly 95%!

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Status : Extinct for 418 million years
Location : Europe, North America
Size : Length up to 4.3ft (1.3m)

Classification : Phylum : Arthropoda -- Class : Merostomata -- Order : †Eurypterida
Family : †Eurypteridae -- Genus : †Eurypterus

Image : Funkmonk

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Carnotaurus

Carnotaurus sastrei

The Carnotaurus is a popular Dinosaur due to its large size (up to 30ft long) and interesting appearance. They had very straight, muscular bodies that allowed them to run quickly, as well as distinctive horns over their eyes.

And yes, that painting is correct-- Carnotarus had tiny arms. Absolutely, minuscule! They make a T. Rex's look huge by comparison! These itty bitty arms were probably function-less, having the same reduced nerve fibers found in the tiny useless wings of flightless birds like Emus.

Carnotaurus lived before the T. Rex, about 72-70 million years ago, during the Late Cretaceous. Their fossils have been found in Argentina, and were only discovered back in 1984. Interestingly, Carnotaurus was the very first Theropod Dinosaur to give us fossilized skin impressions. We know that they were covered in scales, as well as knobby bumps that ran down the back. They were also absent of feathers.

There is some disagreement over what Carnotaurus ate. While it is accepted that they were very fast, and could run down prey, there is dispute over what the prey was. Some argue that their bite strength was low, but the movement was quick, and that they probably captured small creatures and swallowed them whole. Others suggest that their bite was actually very strong, and would've been used to repeatedly attack larger prey. Publications have been going back and forth on this topic for over 15 years.

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Status : Extinct for 70 Million Years
Location : South America
Size : Length up to 30ft (9m)

Classification : Phylum : Chordata -- Clade : Dinosauria -- Clade : Theropoda
Family : †Abelisauridae -- Genus : †Carnotaurus -- Species : † C. sastrei
Image : Nobu Tamura, Ghedoghedo

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Tylosaurus

There are six identified species within the Tylosaurus genus, but T. proriger was the largest. In fact, it's the largest of all the Mosasaurs, and one of the largest marine predators of the Cretaceous period.

These massive sea creatures could grow up to 50ft in length, and sported two rows of teeth in their monstrous jaws. They had incredibly strong tails that allowed them to hunt their prey by ambushing them with sudden bursts of speed. Once caught, the prey was often swallowed whole!

Tylosaurus ate just about everything. Fish, birds, sharks, and other marine reptiles have all been found in their stomachs. Their fossils have been found in Kansas, which was actually completely covered by an ocean 65 million years ago. And though Tylosaurus itself wasn't an actual Dinosaur, they did go extinct at about the same time, around 65 million years ago.

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Status : Extinct for 65 million years
Location : North America
Size : Length up to 50ft (15m)

Classification : Phylum : Chordata -- Class : Reptilia -- Order : Squamata 
Family : Mosasauridae -- Genus : Tylosaurus -- Species : T. proriger
Image : Ryan Somma, Public Domain

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