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Atrociraptor (meaning “savage robber”) is a genus of dromaeosaurid theropod dinosaur from the Late Cretaceous (Maastrichtian stage) of Alberta, Canada.

The type (and only) specimen of Atrociraptor, holotype RTMP 95.166.1, was discovered by Wayne Marshall in 1995, in layers of the Horseshoe Canyon Formation also containing an Albertosaurus bonebed, near Drumheller. This bonebed is located at the top of Unit 4 of the Horseshoe Canyon Formation, which dates to about 68.5 million years ago. The only known specimen consists of parts of the upper and lower jaws — both premaxillae, a right maxilla, both dentaries — teeth and numerous small fragments. The skull appears to have been unusually short and tall. The teeth are relatively straight, but they emerge from the tooth sockets at an angle to the jaw line, resulting in a strongly raked row of teeth. A number of isolated teeth (previously referred to Saurornitholestes) have also been recovered from the Horseshoe Canyon Formation; they can be recognized by their unusually large serrations.

In 2004 Philip J. Currie and David Varricchio named and described the type species of Atrociraptor: Atrociraptor marshalli. The generic name is derived from the Latin atrox, “savage”, and raptor, “seizer”. The specific name honours Marshall.

In 2010 Gregory S. Paul estimated its length at two metres, its weight at fifteen kilogrammes. Atrociraptor differs from Bambiraptor and other velociraptorines in its more isodont dentition — the teeth have different sizes but the same form — and short deep snout. A skull opening, the maxillary fenestra, is relatively large and positioned right above another opening, the promaxillary fenestra, a condition not known from other species.

Atrociraptor was by its describers assigned to the Velociraptorinae within a larger Dromaeosauridae. However, in 2009 Currie published a cladistic analysis showing Atrociraptor to be a member of the Saurornitholestinae.

Teratophoneus is a genus of carnivorous tyrannosaurid theropod dinosaur which lived during the late Cretaceous period (late Campanian age, about 77 to 76 million years ago) in what is now Utah, United States. It is known from an incomplete skull and postcranial skeleton recovered from the Kaiparowits Formation. The Teratophoneus or “monstrous murderer” (Greek: teras, “monster” and phoneus, “murderer”) was specifically named T. curriei in honor of Philip J. Currie.

Life Finds a Way as Jeff Goldblum Heads to Jurassic World 2!

There’s some exciting Jurassic Park franchise news breaking today as The Hollywood Reporter brings word that Jeff Goldblum is set to return for next summer’s still untitled Jurassic World sequel! He joins a cast that currently includes returning stars Chris Pratt and Bryce Dallas Howard alongside Toby Jones, Daniella Pineda, Justice Smith and Rafe Spall. Frank Marshall and Steven Spielberg are returning to produce the film, which has JA Bayona (When a Monster Calls, The Impossible) in the director’s chair.

Bayona (The Impossible, A Monster Calls) will direct the Jurassic World sequel from a script by Colin Trevorrow and Derek Connolly.

Trevorrow previously revealed the quote from the original Jurassic Park that inspired their idea for the sequel, which comes from Sam Neil’s Alan Grant: “Dinosaurs and man, two species separated by 65 million years of evolution have just been suddenly thrown back into the mix together. How can we possibly have the slightest idea what to expect?”

“Every story is different and you need to find the depth of every story and try to express it on the screen,” Bayona recently told CS. “The ‘Jurassic World’ sequel is a more collaborative filmmaker experience, not only with Colin Trevorrow, but also with Steven [Spielberg] and with Frank Marshall. It’s their baby as much as it is mine. It’s about sharing views and working together to bring the story to life. But, at the same time, the way I face telling a story is to find something very personal. I think there will be plenty of myself also in the film.”

Jeff Goldblum previously reprised the Ian Malcolm role for 1997’s The Lost World: Jurassic Park. Although eagle eyed viewers can glimpse his photo in Jurassic World, the new film will mark the first full appearance of the character in more than two decades.

The Jurassic World sequel is set for release on June 22, 2018.

Source: www.comingsoon.net

The richness of paleontological sites in Neuquén province turns it into “the center of paleontology”.

SALTASAURUS LORICATUS

“Salta’s Lizard” was discovered in 1980. This small titanosaurus sauropod from the Late Cretaciaous made a revolution in the field of Paleontology as its back was covered by hard bone plates. This led the scientists to consider the possibility that other sauropods would also have this kind of armour.
It was approximately 12 meters long and would weigh about 8 tons. As all sauropods, it was purely a plant-eater and could stand on its hind legs to reach the higher branches.

NOASAURUS LEALI
This small South American carnivore dwelled the soils of Northwestern Argentina about 73 million years ago. It was discovered in the Lecho Formation, at estancia El Brete, in the South of Salta. It was between 1 and 3 meters long and would weigh approximately 15 kilos. It was slender and light but its fearful curve claws would move fast. Even if it had certain features in common with the Velociraptors dwelling North America and Asia, it was a totally different species. In fact, it was an Abelisaurus, a relative of the Carnotaurus.
This voracious creature proved that dinosaurs did not have to be large to be the most fearful hunters on the planet. It is believed that it fed on young sauropods.

HERRERASAURUS ISCHIGUALASTENSIS

It is one of the most ancient dinosaurs with very primitive features. It dates from approximately 228 million years ago. It became extinct at the end of the Triassic. It was a medium-sized carnivore of about 3.5 meters of length. It was similar to the theropods. It would walk on two legs and had sharp teeth and claws. Its arms were short. It was discovered in the Ischigualasto Formation, in San Juan, in 1958 by Don Victorino Herrera, a local rancher.

RIOJASAURUS INCERTUS

A representative of the primitive family of the prosauropods, the Melanosauridae, this is the most common genre registered in the upper sections of the Los Colorados layers, in the Province of La Rioja. It dwelled this area during the Late Triassic, about 220 million years ago. “La Rioja’s lizard” was one of the first large herbivorous dinosaurs. This heavily-built quadruped was about 10 meters long. It had a long neck, a long tail, a small head, a long, bulky body, and thick, elephant-like legs with claws. The back legs were only slightly larger than the front legs. Its limb bones were solid and thick, but its backbone was hollow. It had spoon-shaped, serrated teeth.

LAGOSUCHUS TALAMPAYENSIS
This archosaur reptile was found in the Talampaya Canyon, in the Province of La Rioja, by an expedition organized by the paleontologist Alfred Romer, from the University of Harvard in 1964. This creature lived 225 million years ago. It shared certain features with the dinosaurs. After two decades, it was considered a new genre and species which was named Marasuchus lilloensis. From the point of view of evolution, only a step separated this animal from the dinosaurs.
It had a pointed long head and a long thin tail. Among its most outstanding features, the skull had two openings behind each eye, one on top of the other, which would allow for the muscles of the jaw to be enlarged while they chewed. It also had an opening in front of each eye, which might have contained a gland. It is precisely due to these characteristics that it has been classified as an archosaurus, from the Greek: “ruling reptile”.

PISANOSAURUS MERTII
This herbivore of the order of the ornithischia lived in Las Lajas, in the Province of La Rioja, around 200 million years ago, when the area was humid and tropical, with lakes, rivers and conifers. It would be 90 centimeters long and would weigh from 7 to 10 kilograms. Its compact teeth allowed it to chew the hard plants typical from semi-arid areas. Its hind limbs were thin and they could reach high speed.

SILLOSUCHUS LONGICERVIX
Found in the Valley of the Moon, in San Juan, it has been considered the ancestor of the present crocodile. It had a graceful and light skeleton. According to the proportions of the bones found, this animal would stand on two legs. It was a carnivore. It lived 220 million years ago and it belongs to the group of the poposaurus.

EORAPTOR LUNENSIS
It is considered the most primitive and complete dinosaur from the inferior section of the Late Triassic 215 millon years ago and it has very valuable anatomical information to understand the first dinosaur evolution stages. This small carnivore was found in the Ischigualasto Formation, in the Valley of the Moon, in San Juan.

PROTEROCHAMPSA BARRIONUEVOI
It was an amphibious carnivore that lived during the Late Triassic, around 215 million years ago in the area of the Ischigualasto Formation, in the Valley of the Moon, in the Province of San Juan. It may be compared to the present crocodiles, but its anatomical structure was much more primitive.
It would hunt small dinosaurs that approached the rivers. It was discovered by Professor Osvaldo A. Reig in 1959.

PTERODAUSTRO GUINAZUI
This pterosaurus, whose name means “South Wing”, was found at Lagarcito, in the Province of San Luis. Due to the characteristics of the area where it was found, it is estimated that it would dwell the lagoons of the arid zones and not the sea coast, like most members of this group. It lived 125 million years ago during the Cretaceous. As every pterosaurus, it is not classified as a dinosaur. It could fly long distances using its large light wings.
It was a carnivore: it would eat fish, mollusk and insects. It had 500 bristle-like teeth on either side of is lower jaw to sieve small organisms out of the water. Its upper jaw contained a series of short blunt teeth, enabling the pterosaur to chop its catch into smaller pieces.

ARGYROSAURUS ENTRERRIENSIS
The “Silver Lizard” was a herbivorous sauropod that lived 70 million years ago during the Late Cretaceous. Being 8 meters high and 30 meters long, it was one of the largest dinosaurs. It was found in the area of Colón, Province of Entre Ríos.

ABELISAURUS COMAHUENSIS

“Abel’s Lizard”, named after its discoverer, Roberto Abel, former director of the Argentinian Museum of Natural Science, dwelled the area of Río Negro during the Late Cretaceous, approximately 75 million years ago. This bipedal carnivore had a single skull which measured 85 centimeters long.
Discovered in 1985 in the surroundings of Lake Pellegrini, in the Province of Río Negro, its heavy teeth indicate that it was possibly in part a scavenger. It was approximately 7 meters long and 2 meters high and it would weigh 1.5 tons. It is believed to have been related to the Carnotaurus.

GASPARINISAURA CINCOSALTENSIS
It has been found recently in the district of Cinco Saltos, in the Province of Río Negro. This herbivore would be very small (1.50 meters), graceful and very fast. According to scientists speculations, it would live in herds, as several adult, young and offspring specimens have been found within an area of 100 m2. It had a tight row of teeth to grind resistant vegetables. The hind legs indicate that it could run quite fast.
It dates back from the Late Cretaceous, about 90 million years ago, when South America was still joined to Antarctica in the South and this to Australia. The fact that fossils of this dinosaur were found in Africa, Australia and Antarctica indicates that they were distributed all through the world before Pangea was fragmented.

ANTARCTOSAURUS WICHMANNIANUS
With a small head and a short flat skull, the “Southern Lizard” may have been one of the largest sauropods, according to the fossils found in the Río Colorado Formation sediments, in the Province of Río Negro in the early XX, which include a 2.20-meter-long femur. It is believed that this reptile was approximately 18 meters long and 6 meters high, which turned it into the largest sauropod in South America. It is related to the similarly gigantic Argentinosaurus and it belongs to the group of the titanosaurs.
It dwelled the southernmost tip of the present American continent during the Cretaceous about 75 million years ago. Its teeth were located at the front of its jaw, which indicates that it would rip the food without chewing.

GIGANOTOSAURUS CAROLINII

The “Carolinii”, considered the largest carnivorous dinosaur in the world, surpasses the famous Tyranosaurus rex in size. It was discovered in July, 1993, by Rubén Darío Carolini, present Director of the Villa El Chocón Municipal Museum, in a former lagoon located 18 kilometers to the South of Villa El Chocón.
80% of the fossil material of this specimen has been rescued and preserved in optimum condition. This carnivore, with reduced fore limbs, biped gait and with three toes in each leg, would measure 13.5 meters of length and its hip could reach 4.6 meters. It is estimated that it would weigh 9.5 tons when it was alive. Its head would measure 2 meters and its longest tooth, 21 centimeters. This specimen belongs to the Mid Cretaceous from the Mesozoic Era and it dwelled the Plaza Huincul area 90 million years ago.

AMARGASAURUS CAZAUI

“Amarga’s Lizard” was a sauropod from the Early Cretaceous. Its fossils were discovered by paleontologist José Bonaparte in 1991 in a canyon in La Amarga, a town in the Province of Neuquén, located approximately 70 kilometers from Zapala. The species name cazaui is due to Dr. Luis Cazau, a geologist who worked for the state oil company YPF and with Bonaparte’s team in 1983 at La Amarga.
This herbivore dwelled the area approximately 120 million years ago. It was 10 meters long and would weigh about five tons. It was differenciated from other sauropods by two parallel rows of large “spikes” that ran along its neck up to the tail. They may have been connected by a skin membrane, forming a double “sail” that might have worked as a thermoregulatory structure, used to absorb and release heat, for mating and dominance rituals, and for making this creature look much larger than it was to predators. Otherwise, the spines were probably used for protection. Amargasaurus was a quadruped, had a small head, a long neck and a very long whip-like tail.
Its front legs were shorter than its back legs, and all the legs had five-toed feet and a thumb claw, probably used for protection.
According to Bonaparte’s investigations, the Amargasaurus is closely related to two species from the Jurassic found in Tanzania.
It is believed that it ate large amounts of plant material a day to sustain itself and that it would swallow leaves without chewing. It had blunt teeth to rip the foliage easily.
It moved in herds and it may have migrated when food supply became scarce.

ARGENTINOSAURUS HUINCULENSIS

Named Huinculensis after the district of Plaza Huincul where its fossil remains were found, in the Province of Neuquén. This is the largest herbivorous dinosaur found so far. Its size is even larger than the “Carolinii”, which was a carnivore.
It belongs to the Mid Cretaceous period. It is estimated that it is 98 million years old. It was rescued by the staff of the Carmen Funes Museum in Plaza Huincul, where original pieces of the find are exhibited.
This is a great sauropod, some of its dorsal vertebras are the largest ever recorded. They are 1.70 meters high.

ANDESAURUS DELGADOI
In 1987, a campaign organized by the Comahue National University extracted some vertebras and part of the hip of a dinosaur that was later called Andesaurus delgadoi after its discoverer Alejandro Delgado.
It was found several meters under the waters of Lake Exequiel Ramos Mejía, formed by the El Chocón Dam. The rescue took place when the level of the lake went lower than its historical records. It is estimated that the creature was 15 meters long.
At present, it is exhibited at the Comahue National University Geology and Paleontology Museum.

REBBACHISAURUS TESSONEI
In 1988, the most complete specimen in South America was found in Villa El Chocón. It was called Rebbachisaurus Tessonei. This is a sauropod, herbivorous middle-sized dinosaur, which would weight about 10 tons and measure 17 meters of length. Nowadays, it is exhibited at the Geology and Paleontology Museum. In turn, the Rebbachisaurus tessonei was one of the favourite dishes of the largest carnivore of all times -the Giganotosaurus carolinii.
According to experts Jorge Calvo and Leonardo Salgado, these huge animals with very long tails and necks would wander about the area on their four legs over one hundred million years ago, devouring the exuberant vegetation that would cover the marshlands.

CARNOTAURUS SASTREI

This large predator, similar to the Tiranosaurus rex lived in the Argentinian Patagonia around 90 million years ago and was discovered in Chubut by José F. Bonaparte, discoverer of many other South American dinosaurs.
Its most outstanding features include two thick bull-like horns above the eyes that are the reason for its name, and the extremely reduced forelimbs with four fingers. It had a small skull, a thick chest, and a thin tail. The eyes of the Carnotaurus faced forward, which is unusual in a dinosaur, and may indicate binocular vision and depth perception. It was 10 meters long and 4 meters high, and it belonged to the group of the most spectacular South American dinosaurs: the Abelisauridae.

TITANOSAURUS AUSTRALIS
This is one of the sauropod dinosaurs that has been most thouroughly studied. It did not surpass the 8 meters of length, although other representatives of its family (also exhibited in the museum) would loosely surpass this measure. Almost spherical fossil eggs of these animals have been found. One of these eggs belongs to the collection of the museum and may be observed by visitors. This dinosaur stepped on Patagonia approximately 85 million years ago, during the Upper Cretaceous.

PIATNITZKYSAURUS FLORESI
Found in the Cañadón Asfalto Formation in the Province of Chubut, this carnivorous dinosaur would belong to the group of the theropods. It dwelled the area during the Mid Jurassic, 165 million years ago. This 5-meter-long creature was an active hunter that may have attacked in groups. It would feed on young sauropods. Its large curve claws were used while hunting as a complement to its formidable conical very compressed long teeth, which were bent backwards and quite sharp. This suggested that the animal was not a fierce predator of large prey but of small vertebrates. It walked on two legs for its hind limbs were long and strong in comparison with its reduced fore limbs. Its strong head would measure approximately 50 centimeters.

MEGARAPTOR NAMUNHUAIQUII
The “Giant Robber”, a large predator from the Late Cretaceous, had fearful sickle-shaped claws. It walked on two slender, bird-like legs. It had a curve flexible neck, a huge head and serrated teeth in its powerful jaw. It used its tail to manage perfect balance and turn fast. This 7-meter- long carnivore dwelled the Northwestern area of the Argentinian Patagonia and was discovered by paleontologist Fernando E. Novas.

NOTOCERATOPS
This quadruped dinosaur was herbivorous and had horns and a beak similar to that of a parrot. It had a large head, a bulky body, a parrot-like beak, cheek teeth, and a small frill on its head. It was quite slow.
It lived in the Late Cretaceous, approximately 80 million years ago, towards the end of the Mesozoic, the Age of Reptiles.
In 1918, Augusto Tapia found part of a lower jaw that would belong to this specimen in Chubut.

QUILMESAURUS CURRIEI
Named after the Quilmes Indians, this medium-sized carnivore lived during the Late Cretaceous. It is estimated that it was 5-6 long. Fossil remains of this theropod were found in the Allen Formation, Salitral Ojo de Agua, in the Province of Río Negro.

UNENLAGIA COMAHUENSIS

This is the most bird-like dinosaur ever discovered. This theropod from the Mid-Cretaceous is 90 million years ago. The first birds appeared 150 million years ago, evolving from dinosaurs long before Unenlagia lived. This proves that it is not an ancestor of modern-day birds.
With the size of an ostrich, but shaped like a Velociraptor, this fightless carnivore was 1.20 meters tall and 2 meters long. Its fossil remains have provided evidence to prove how dinosaur forearms evolved into the wings of modern-day birds.
The Unenlagia had a special shoulder structure that allowed it to move its short arms forwards, backwards and inwards to catch their prey, and upwards and downwards in a flapping motion which, even if not used for flying, because its wing-like arms were too short to support the heavy dinosaur, were used for balancing and turning. Although there is no fossil evidence of feathers from its fossils, it may well have had them.
Fernando Novas, from the Museum of Natural History of Buenos Aires gave this dinosaur the name of Unenlagia comahuensis, which means “half-bird from Northwestern Patagonia”.

Source: www.welcomeargentina.com

Meet Sarcosuchus, the 10-Ton Prehistoric Crocodile

Sarcosuchus Is Also Known as the SuperCroc

Sarcosuchus Kept Growing Throughout its Life Span

Sarcosuchus Adults May Have Weighed More than 10 Tons

Sarcosuchus May Have Tangled With Spinosaurus

The Eyes of Sarcosuchus Rolled Up and Down, not Left and Right

Sarcosuchus Lived in What (Today) Is the Sahara Desert

The Snout of Sarcosuchus Ended in a “Bulla”

Sarcosuchus Mostly Subsisted on Fish

Sarcosuchus Was Technically a “Pholidosaur”

Sarcosuchus Was Covered Head to Tail in Osteoderms

The Plesiosauria (Greek: πλησίος, plesios, meaning “near to” and Sauria) or plesiosaurs are an order or clade of Mesozoic marine reptiles (marine Sauropsida), belonging to the Sauropterygia.

Plesiosaurs first appeared in the latest Triassic Period, possibly in the Rhaetian stage, about 203 million years ago. They became especially common during the Jurassic Period, thriving until their disappearance due to the Cretaceous–Paleogene extinction event at the end of the Cretaceous Period, about 66 million years ago. They had a worldwide oceanic distribution.

Plesiosaurs were among the first fossil reptiles discovered. In the beginning of the nineteenth century, scientists realised how distinctive their build was and they were named as a separate order in 1835. The first plesiosaurian genus, the eponymous Plesiosaurus, was named in 1821. Since then, more than a hundred valid species have been described. In the early twenty-first century, the number of discoveries has increased, leading to an improved understanding of their anatomy, relationships and way of life.

Plesiosaurs had a broad flat body and a short tail. Their limbs had evolved into four long flippers, which were powered by strong muscles attached to wide bony plates formed by the shoulder girdle and the pelvis. The flippers made a flying movement through the water. Plesiosaurs breathed air, and bore live young; there are indications that they were warm-blooded.

Plesiosaurs showed two main morphological types. Some species, with the “plesiosauromorph” build, had (sometimes extremely) long necks and small heads; these were relatively slow and caught small sea animals. Other species, some of them reaching a length of up to seventeen metres, had the “pliosauromorph” build with a short neck and a large head; these were apex predators, fast hunters of large prey. The two types are related to the traditional strict division of the Plesiosauria into two suborders, the long-necked Plesiosauroidea and the short-neck Pliosauroidea. Modern research, however, indicates that several “long-necked” groups might have had some short-necked members or vice versa. Therefore, the purely descriptive terms “plesiosauromorph” and “pliosauromorph” have been introduced, which do not imply a direct relationship. “Plesiosauroidea” and “Pliosauroidea” today have a more limited meaning. The term “plesiosaur” is properly used to refer to the Plesiosauria as a whole, but informally it is sometimes meant to indicate only the long-necked forms, the old Plesiosauroidea.

Size

In general, plesiosaurians varied in adult length from between 1.5 metres (5 ft) to about 15 metres (49 ft). The group thus contained some of the largest marine apex predators in the fossil record, roughly equalling the longest ichthyosaurs, mosasaurids, sharks and toothed whales in size. Some plesiosaurian remains, such as a 2.9 metres (10 ft) long set of highly reconstructed and fragmentary lower jaws preserved in the Oxford University Museum and referable to Pliosaurus rossicus(previously referred to Stretosaurus and Liopleurodon), indicated a length of 17 metres (56 ft). However, it was recently argued that its size cannot be currently determined due to their being poorly reconstructed and a length of thirteen metres is more likely. MCZ 1285, a specimen currently referable to Kronosaurus queenslandicus, from the Early Cretaceous of Australia, was estimated to have a skull length of 2.85 m (9 ft).

Skeleton

The typical plesiosaur had a broad, flat, body and a short tail. Plesiosaurs retained their ancestral two pairs of limbs, which had evolved into large flippers. Plesiosaurs were related to the earlier Nothosauridae, that had a more crocodile-like body. The flipper arrangement is unusual for aquatic animals in that probably all four limbs were used to propel the animal through the water by up-and-down movements. The tail was most likely only used for helping in directional control. This contrasts to the ichthyosaurs and the later mosasaurs, in which the tail provided the main propulsion.

To power the flippers, the shoulder girdle and the pelvis had been greatly modified, developing into broad bone plates at the underside of the body, which served as an attachment surface for large muscle groups, able to pull the limbs downwards. In the shoulder, the coracoid had become the largest element covering the major part of the breast. The scapula was much smaller, forming the outer front edge of the trunk. To the middle, it continued into a clavicle and finally a small interclavicular bone. As with most tetrapods, the shoulder joint was formed by the scapula and coracoid. In the pelvis, the bone plate was formed by the ischium at the rear and the larger pubic bone in front of it. The ilium, which in land vertebrates bears the weight of the hindlimb, had become a small element at the rear, no longer attached to either the pubic bone or the thighbone. The hip joint was formed by the ischium and the pubic bone. The pectoral and pelvic plates were connected by a plastron, a bone cage formed by the paired belly ribs that each had a middle and an outer section. This arrangement immobilised the entire trunk.

To become flippers, the limbs had changed considerably. The limbs were very large, each about as long as the trunk. The forelimbs and hindlimbs strongly resembled each other. The humerus in the upper arm, and the thighbone in the upper leg, had become large flat bones, expanded at their outer ends. The elbow joints and the knee joints were no longer functional: the lower arm and the lower leg could not flex in relation to the upper limb elements, but formed a flat continuation of them. All outer bones had become flat supporting elements of the flippers, tightly connected to each other and hardly able to rotate, flex, extend or spread. This was true of the ulna, radius, metacarpals and fingers, as well of the tibia, fibula, metatarsals and toes. Furthermore, in order to elongate the flippers, the number of phalanges had increased, up to eighteen in a row, a phenomenon called hyperphalangy. The flippers were not perfectly flat, but had a lightly convexly curved top profile, like an airfoil, to be able to “fly” through the water.

Source: www.wikipedia.com, www.ifls.com

Ammonoids are an extinct group of marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs are more closely related to living coleoids (i.e., octopuses, squid, and cuttlefish) than they are to shelled nautiloids such as the living Nautilus species. The earliest ammonites appear during the Devonian, and the last species died out during the Cretaceous–Paleogene extinction event.

Ammonites are excellent index fossils, and it is often possible to link the rock layer in which a particular species or genus is found to specific geologic time periods. Their fossil shells usually take the form of planispirals, although there were some helically spiraled and nonspiraled forms (known as heteromorphs).

The name “ammonite”, from which the scientific term is derived, was inspired by the spiral shape of their fossilized shells, which somewhat resemble tightly coiled rams’ horns. Pliny the Elder (d. 79 AD near Pompeii) called fossils of these animals ammonis cornua (“horns of Ammon”) because the Egyptian god Ammon (Amun) was typically depicted wearing ram’s horns. Often the name of an ammonite genus ends in –ceras, which is Greek (κέρας) for “horn”.

Ammonites (subclass Ammonoidea) can be distinguished by their septa, the dividing walls that separate the chambers in the phragmocone, by the nature of their sutures where the septa joint the outer shell wall, and in general by their siphuncles.

Septa

Ichthyosaurs (Greek for “fish lizard” – ιχθυς or ichthys meaning “fish” and σαυρος or sauros meaning “lizard”) are large marine reptiles. Ichthyosaurs belong to the order known as Ichthyosauria or Ichthyopterygia (‘fish flippers’ – a designation introduced by Sir Richard Owen in 1840, although the term is now used more for the parent clade of the Ichthyosauria).

Ichthyosaurs thrived during much of the Mesozoic era; based on fossil evidence, they first appeared approximately 250 million years ago (mya) and at least one species survived until about 90 million years ago, into the Late Cretaceous. During the early Triassic Period, ichthyosaurs evolved from a group of unidentified land reptiles that returned to the sea, in a development parallel to that of the ancestors of modern-day dolphins and whales, which they gradually came to resemble in a case of convergent evolution. They were particularly abundant in the later Triassic and early Jurassic Period, until they were replaced as the top aquatic predators by another marine reptilian group, the Plesiosauria, in the later Jurassic and Cretaceous Period. In the Late Cretaceous, ichthyosaurs became extinct for unknown reasons.

Science became aware of the existence of ichthyosaurs during the early nineteenth century when the first complete skeletons were found in England. In 1834, the order Ichthyosauria was named. Later that century, many excellently preserved ichthyosaur fossils were discovered in Germany, including soft tissue remains. Since the late twentieth century, there has been a revived interest in the group leading to an increased number of named ichthyosaurs from all continents, over fifty valid genera being now known.

Ichthyosaur species varied from one to over sixteen metres in length. Ichthyosaurs resembled both modern fish and dolphins. Their limbs had been fully transformed into flippers, which sometimes contained a very large number of digits and phalanges. At least some species possessed a dorsal fin. Their heads were pointed, the jaws often equipped with conical teeth to catch smaller prey. Some species had larger bladed teeth to attack large animals. The eyes were very large, probably for deep diving. The neck was short and later species had a rather stiff trunk. These also had a more vertical tail fin, used for a powerful propulsive stroke. The vertebral column, made of simplified disc-like vertebrae, continued into the lower lobe of the tail fin. Ichthyosaurs were air-breathing, bore live young, and were probably warm-blooded.

Source: www.NatGeo.com, www.Wikipedia.com

“Sue” is the nickname given to FMNH PR 2081, which is the largest, most extensive and best preserved Tyrannosaurus rex specimen ever found at over 90% recovered by bulk. It was discovered in August of 1990, by Sue Hendrickson, a paleontologist, and was named after her. After ownership disputes were settled, the fossil was auctioned in October 1997, for US $7.6 million, the highest amount ever paid for a dinosaur fossil, and is now a permanent feature at the Field Museum of Natural History in Chicago, Illinois. It has a length of 12.3 meters (40 ft), stands 3.66 m (12 ft) tall at the hips, and according to the most recent studies estimated to have weighed between 8.4 to 18.5 metric tons when alive. In one of these studies, estimations by Hutchinson et al. (2011) point out to a figure of 13.99 metric tonnes being the average estimate. Authors have stated that their upper [18.5 metric tonnes] and lower [9.5 metric tonnes] estimates were based on models with wide error bars and that they “consider [them] to be too skinny, too fat, or too disproportionate”. Historically older estimations have produced figures as low as 6.4 metric tonnes for this specimen.

Discovery

During the summer of 1990, a group of workers from the Black Hills Institute, located in Hill City, searched for fossils at the Cheyenne River Indian Reservation in western South Dakota near the city of Faith. By the end of the summer, the group had discovered Edmontosaurus bones and was ready to leave. However, a flat tire was discovered on their truck before the group could depart on August 12.  While the rest of the group went into town to repair the truck, Sue Hendrickson decided to explore the nearby cliffs that the group had not checked. As she was walking along the base of a cliff, she discovered some small pieces of bone. She looked above her to see where the bones had originated, and observed larger bones protruding from the wall of the cliff. She returned to camp with two small pieces of the bones and reported the discovery to the president of the Black Hills Institute, Peter Larson. He determined that the bones were from a T. rex by their distinctive contour and texture. Later, closer examination of the site showed many visible bones above the ground and some articulated vertebrae. The crew ordered extra plaster and, although some of the crew had to depart, Hendrickson and a few other workers began to uncover the bones. The group was excited, as it was evident that much of the dinosaur had been preserved. Previously discovered T. rex skeletons were usually missing over half of their bones. It was later ascertained that Sue was a record 90 percent complete by bulk. Scientists believe that this specimen was covered by water and mud soon after its death which prevented other animals from carrying away the bones. Additionally, the rushing water mixed the skeleton together. When the fossil was found the hip bones were above the skull and the leg bones were intertwined with the ribs. The large size and the excellent condition of the bones were also surprising. The skull was nearly five feet long (1394 millimeters), and most of the teeth were still intact. After the group completed excavating the bones, each vertebra was covered in burlap and coated in plaster, followed by a transfer to the offices of The Black Hills Institute where preparators began to clean the bones.

Dispute and auction

Soon after the fossils were found, a dispute arose over their legal ownership. The Black Hills Institute had obtained permission from the owner of the land, Maurice Williams, to excavate and remove the skeleton, and had, according to Larson, paid Williams US$5,000 for the remains. Williams later claimed that the money had not been for the sale of the fossil and that he had only allowed Larson to remove and clean the fossil for a later sale. Williams was a member of the Sioux tribe, and the tribe claimed the bones belonged to them. However, the property that the fossil had been found within was held in trust by the United States Department of the Interior. Thus, the land technically belonged to the government. In 1992, the FBI and the South Dakota National Guard raided the site where The Black Hills Institute had been cleaning the bones and seized the fossil. The government transferred the remains to the South Dakota School of Mines and Technology, where it was stored until the legal dispute was settled. After a lengthy trial, the court decreed that Maurice Williams retained ownership, because as a beneficiary he was protected by the law against an impulsive selling of real property, and the remains were returned in 1995. Williams then decided to sell the remains, and contracted with Sotheby’s to auction the property. Many were then worried that the fossil would end up in a private collection where people would not be able to observe it. The Field Museum in Chicago was also concerned about this possibility, and decided to attempt to purchase Sue. However, the organization realized that they might have had difficulty securing funding and requested that companies and private citizens provide financial support. The California State University system, Walt Disney Parks and Resorts, McDonald’s, Ronald McDonald House Charities, and individual donors agreed to assist in purchasing Sue for The Field Museum. On October 4, 1997, the auction began at US$500,000; less than ten minutes later, The Field Museum had purchased the remains with the highest bid of US$7.6 million. The final cost after Sotheby’s commission was US$8,362,500. Williams received the $7.6 million tax free due to being a sale of Trust Land.

Tylosaurus was a mosasaur, a large, predatory marine lizard closely related to modern monitor lizards and to snakes.

A distinguishing characteristic of Tylosaurus is its elongated, cylindrical premaxilla (snout) from which it takes its name and which may have been used to ram and stun prey and also in intraspecific combat. Early restorations showing Tylosaurus with a dorsal crest were based on misidentified tracheal cartilage, but when the error was discovered, depicting mosasaurs with such crests was already a trend.

Along with plesiosaurs, sharks, fish, and other mosasaurs, Tylosaurus was a dominant predator of the Western Interior Seaway during the Late Cretaceous. The genus was among the largest of the mosasaurs (along with Mosasaurus hoffmannii), with the possibly conspecific Hainosaurus bernardi reaching lengths up to 12.2 m (40 ft), and T. pembinensis reaching comparable sizes. T. proriger, the largest species of Tylosaurus, reached lengths up to 14 m (46 ft).

Like many other mosasaurs, the early history of this taxon is complex and involves the infamous rivalry between two early American paleontologists, Edward Drinker Cope and Othniel Charles Marsh. Originally, the name “Macrosaurus” proriger was proposed by Cope  for a fragmentary skull and thirteen vertebrae collected from near Monument Rocks in western Kansas in 1868. It was placed in the collections of the Harvard Museum of Comparative Zoology. Only a year later, Cope redescribed the same material in greater detail and referred it, instead, to the English mosasaur taxon Liodon. Then, in 1872, Marsh named a more complete specimen as a new genus, Rhinosaurus (“nose lizard”), but soon discovered that this name had already been used for a different animal. Cope suggested that Rhinosaurus be replaced by yet another new name, Rhamposaurus which also proved to be preoccupied. Marsh finally erected Tylosaurus later in 1872, to include the original Harvard material as well as additional, more complete specimens which had also been collected from Kansas. A giant specimen of T. proriger, recovered in 1911 by C. D. Bunker near Wallace, Kansas is one of the largest skeleton of Tylosaurus ever found. It is currently on display at the University of Kansas Museum of Natural history.

A 34 feet (10 m) long Tylosaurus found in Kansas by Alan Komrosky in 2009 is now on display at the Museum of World Treasures in Wichita, Kansas.