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Main article: Fossils

Subphylum Vertebrata

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Physical Description Have a backbone and cranium.
Fossil Range Evolved during the Cambrian Explosion.
Taxonomy Kingdom: Animalia
Phylum: Chordata
Adaptations Over Time Slowly became bigger and more terrestrial. They evolved bigger jaws and stronger bones.

Superclass Agnatha (Jawless Fish) (Ostracoderms)

This fossil will only be tested at the State and National levels.

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Common Names Jawless fish, including lampreys and hagfish.
Physical Description They lack paired appendages and jaws. They have skin but no dermal or epidermal scales. Instead of stomachs, they simply have one long gut. Cold-blooded (ectothermic). Two-chambered heart. They have seven or more paired gill pouches. Possess a notochord (a cartilage-like rod that is a characteristic feature of all chordates in at least one stage of life) during their larval and adult stages. They possess a photoreceptive parietal eye for regulating circadian rhythm and body heat. The skeleton is made of cartilage.
Fossil Range Cambrian Explosion to present-day.
Taxonomy Agnatha is split up into Cyclostomata (extant and comprising lampreys and hagfish, ~120 species), Conodonta (extinct), and Ostracoderms (extinct). Sister taxon to Gnathostomata (jawed vertebrates). rRNA and mtDNA data suggest that Cyclostomata is monophyletic.
Mode of Life or Habitat Cold marine waters from 10 meters deep at high latitudes to 1300 meters at low altitudes. Lampreys feed on other fish and mammals. Hagfish are scavengers. No known parental care, fertilization is most likely external.
Distribution Worldwide, except for tropics and polar regions.
Etymology Ancient Greek for "without jaws."
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Class Placodermi (Armored Jawed Fish)

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Common Names Placoderms
Physical Description Most were small fish reaching lengths of 15 cm; however, a few species reached lengths of 4 to 10 meters. They all have jaws, an internal skeleton, head and trunk armor, paired fins, and projecting spines to the sides of the trunk shield. A neck joint allowed them to lift the anterior portion of their head shield. The head and thorax are covered by armored, bony plates. The rest of the body is either covered in small plates or has no plates. The bony plates have three layers, a basal layer made of compact bone, a middle layer made of spongy bone, and a superficial layer.
Fossil Range Early Silurian (in China) to the Late Devonian (“Age of Fish”). They became extinct at the end-Devonian Hangenberg event.
Taxonomy Infraphylum: Gnathostomata.
Thought to be paraphyletic, consisting of sister groups to modern jawed vertebrates. However, they could be monophyletic. First studied by Louis Agassiz, 1833-1843.
Mode of Life or Habitat Placoderms lived in both marine and freshwater environments. They were predators and some may have been filter feeders.
Adaptations Over Time One of the first fish that developed jaws. They evolved jaws from their gill arches. Instead of teeth, they had bony plates. First fish to develop paired pelvic fins, which would later develop into hindlimbs. First fish to develop true teeth. Some genera in this class exhibit the oldest known examples of live birth.
Distribution Worldwide distribution by the Devonian.
Etymology Comes from the Greek for plate-skinned or tablet-skinned.
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Genus Bothriolepis

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Physical Description Around 30 cm long, but the largest species (B. rex) could be 170 cm long. Lifted their bodies with pectoral fins. Bothriolepis also could have used its fins to throw sediment over itself. Had heavily armored heads attached to the thoracic shield and two holes on their heads (one on the upper side for the eyes and nose and one on the lower side for the mouth), along with preorbital recesses (separate bones below the eyes and noses). The thoracic shield covered almost half of their body. In addition to its gills, they had pouches that connected to the oesophagus, which may have been rudimentary lungs that may have allowed them to live for short periods out of the water. The two halves of the jaw are separate, and adults can use them independently of one another. The tail (caudal fin) was long and is rarely preserved due to its soft nature.
Fossil Range (Middle and) Late Devonian, ~387-360 mya.
Taxonomy Order: Antiarchi
Family: Bothriolepididae
Mode of Life or Habitat Benthic detritus feeders. Found in both shore marine and freshwater. Likely to have spent most of its life in freshwater but probably entered saltwater at times.
Distribution Widespread and abundant. Worldwide, in every paleo-continent.
Etymology Means pitted scale or trench scale in Greek.
Additional Information Bothriolepis is a diverse genus.
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Genus Dunkleosteus

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Physical Description Some of the largest placoderms. Largest species could grow up to 8.79 m long. Could open and close jaws very quickly, with a bite force of 6000 N. Could weigh up to 4 tons. Instead of teeth, they had 2 pairs of sharp plates which formed a beak. Juveniles likely also had large bite forces.
Fossil Range Late Devonian, 382-352 mya. It became extinct in the Hangenberg event.
Taxonomy Order: Arthrodira
Family: Dunkleosteidae
Mode of Life or Habitat Hypercarnivorous apex predators. Diet could have included armored prey such as ammonites and other placoderms. Sometimes cannibalized. May have been pelagic. They were slow swimmers so they ambushed their prey to hunt. Lived in shallow waters as juveniles, then moved to deeper waters. Speed of jaw opening and closing is consistent with suction feeding, where prey is sucked into the predator's mouth.
Adaptations Over Time May have been among the first vertebrates to internalize egg fertilization.
Distribution Many fossils have been found in North America, Belgium, Morocco, and Poland.
Etymology Named in 1956 after David Dunkle, a paleontologist at the Cleveland Museum of Natural History. ὀστέον, "osteon" is Greek for bone.
Additional Information Only about 5% of specimens have more than a quarter of the skeleton preserved. Specimens often found with boluses (balled up mix of food and saliva) of fish bones, may have regurgitated bones instead of digesting them.
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Class Chondrichthyes (Cartilaginous Fish)

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Common Names Cartilaginous fish.
Physical Description Have skeletons made of cartilage with tough skins covered in sharp tooth-like scales (dermal denticles or placoid scales) which are all oriented in one direction. Electric rays are the exception: they have flabby bodies. Chondrichthyans have paired fins and paired nostrils. Their hearts have two chambers in series. The notochord is replaced by vertebrae. They lack bone marrow: red blood cells are created in the spleen and epigonal organ. Some sharks and rays have Leydig's organs which also produce red blood cells. They have five to seven pairs of gills. Sharks, skates, and rays have special electrosensory organs known as ampullae of Lorenzini. Some species have two dorsal (back) fins while some have one dorsal fin. The pectoral (side) fins are used for steering. The pelvic fin is found on the stomach and stabilizes the body. The clasper is an organ in males found near the pelvic fin used for mating. The tail is called the caudal fin and gives propulsion. It is heterocercal, meaning the upper lobe is bigger than the lower lobe and contains part of the vertebral column. The anal fin, if present, is also used for stabilization.
Fossil Range Late Silurian to recent.
Taxonomy Infraphylum: Gnathostomata. Split into two subclasses: Elasmobranchii (sharks, rays, skates, and sawfish) and Holocephali (chimaeras/ghost sharks).
Mode of Life or Habitat Can be pelagic (in which case they must keep swimming to get water through their gills) or demersal (in which case they can pump water in through the spiracles behind their eyes and out through their gills). Due to their lack of a swim bladder, pelagic species must continuously swim to avoid sinking (buoyancy is given by large amounts of liver oil). Most are marine. Only 5% are restricted to freshwater (e.g. the freshwater stingray). Half of the species live down to depths of 200 m (on the continental slope) while 35% live in depths of 200-2000 m. Beyond that, high salinity and low oxygen levels pose as barriers. Only 5% swim through the open ocean (e.g. the great white shark). Some give birth to eggs surrounded by egg cases/capsules while others give live birth. Predators.
Adaptations Over Time Among the first vertebrates to evolve jaws and bony teeth. Evolved from spiny sharks (Acanthodii). Very diverse group.
Distribution Waters worldwide.
Etymology From Greek "cartilage fish," χονδρ chondr "cartilage" + ἰχθύς ichthys "fish."
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Superorder Selachimorpha (Sharks)

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Common Names Sharks
Physical Description Usually streamlined body. The jaws are not attached to the cranium. They shed and replace their teeth and scales. The teeth are made of calcium phosphate, an apatite. The pectoral fin is not fused to the head. Can range from 17 cm (the pygmy shark) to 12 m (the whale shark).
Fossil Range Late Silurian to modern-day, 425- mya.
Taxonomy Subclass: Elasmobranchii
Mode of Life or Habitat Common to depths of 2000 m. Usually do not dwell in freshwater, although some do (bull shark and river shark can be found in freshwater and seawater). Well-known species are apex predators. Poikilotherms, "cold-blooded." Most live 20 to 30 years. Sharks practice internal fertilization.
Adaptations Over Time Sharks have a hydrodynamic shape in order to swim with less resistance, with tapered ends at the head and tail. Most sharks are dark with pale bellies, with camouflages them from above and below.
Distribution Waters worldwide.
Etymology The origin of the word "shark" is uncertain.
Additional Information Some have biofluorescence. Some species can detect as little as 1 ppm of blood in seawater.
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Genus Otodus

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Common Names A type of mackerel shark (all sharks in Lamniformes are mackerel sharks).
Physical Description The teeth could get to 10.4 cm tall, and the vertebral centrum could get over 12.7 cm wide. Thus, the maximum length of the shark is estimated to be between 9.1 and 12.2 meters long. The teeth have a triangular crown and smooth cutting edges with visible cusps on the roots.
Fossil Range Paleocene to Pleistocene (66-0.34 mya).
Taxonomy Order: Lamniformes
Family: Otodontidae.
Mode of Life or Habitat Top predator. Likely preyed on large bony fish, aquatic mammals, and other sharks.
Adaptations Over Time Transitional teeth show Otodus evolving into Carcharocles. These teeth have lightly serrated cusplets and serrated cutting edges and are found all over the world (Maryland, Belgium, and Kazakhstan), implying that the evolution occurred worldwide. The ancestor of Carcharocles is thought to be O. aksuaticus.
Distribution Worldwide.
Etymology Ancient Greek ὠτ (ōt, "ear") and ὀδούς (odoús, "tooth"), combining to make "ear-shaped tooth."
Additional Information Fossilized parts are teeth and vertebrae.
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Genus Carcharocles

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Physical Description Carcharocles is estimated to be 13 meters long - they are one of the world's largest predators. They have about 24 teeth in their upper jaw and 20 in their lower jaw.
Fossil Range Early Eocene to Pliocene
Taxonomy Order: Lamniformes
Family: Otodontidae
Sometimes considered a subgenus of Otodus, the genus from which it is said to have descended.
Mode of Life or Habitat They could be found in shallow coastal waters, swampy coastal lagoons, offshore deep water environments, etc. They are a transient species - they often move around.
Distribution Found worldwide (in North and South America, Africa, Europe, Japan, Australia and New Zealand).
Additional Information In Greek, Carcharocles means "Famed for Jaggedness."

Species C. megalodon

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Common Names Megalodon
Physical Description Around 10.5 m long on average and up to 16 m. Their jaws could exert forces of up to 180000 N. Large, triangular teeth with serrations and a V-shaped neck. In 1926, a partial vertebral column was found in Belgium made up of 150 vertebral centra. The centra were 5.5-15.5 cm in diameter. May have looked similar to a great white shark. Its skeleton was heavily calcified. They had about 276 teeth in 5 rows.
Fossil Range Late Oligocene to late Pliocene, ~28-2.6 mya.
Taxonomy Agassiz assigned the species to Carcharodon (great white sharks) in 1843. Another genus that the megalodon is commonly designated under is Otodus.
Mode of Life or Habitat Adults were not abundant in shallow water environments, and mostly lurked offshore. They gave birth to their young in shallow water environments. Top predator. Probably ate large animals such as whales, seals, and sea turtles.
Distribution Worldwide. Teeth have been found in the Mariana Trench.
Etymology Megalodon means "big tooth" in Greek.
Additional Information Went extinct from numerous different factors including the cooling of the ocean, sea level drops, and habitat loss due to the Ice Age, as well as competition from whale-eating whales for food. After the megalodon went extinct, baleen whales became significantly larger. In the Renaissance, megalodon teeth were thought to be the tongues of dragons and snakes and were called glossopetrae.
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Superorder Batoidea (Rays)

This fossil will only be tested at the State and National levels.

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Common Names Rays and skates
Physical Description Flat bodies made of a tough, elastic material. Disk-like bodies. Rays and skates always have spiracles, unlike sharks, which are holes behind the eyes that allow oxygen into the body. The eyes are on the top of the head, unlike sharks which have eyes on the sides. The pectoral fins are not distinct, whereas sharks have distinct pectoral fins. Rays and skates swim by flapping their pectoral fins like wings. The tails are whip-like, and the gills are under the body (five gill openings). They have heavy, rounded teeth for crushing the shells of prey. Some rays may have tails that contain venom. The flat body combines with the color of the top of the body to allow the ray to camouflage in the sand, waiting overhead for prey.
Fossil Range Early Triassic to present-day.
Taxonomy Subclass: Elasmobranchii
Contains more than 500 species, and 13 families.
Mode of Life or Habitat Usually live on the seafloor in coastal waters. Mostly docile and slow-moving. Varied diets: they eat mostly fishes and invertebrates. Some eat plankton and other small organisms. Rays exhibit internal fertilization, giving birth to live young. Skates give birth to egg cases, which have been called "mermaid's purses."
Distribution Worldwide. They prefer tropical and subtropical waters.
Etymology Named after Batis, a genus of sparrow-like birds.
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Superclass Osteichthyes (Bony Fish)

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Common Names Bony fish
Physical Description Fish with bone skeletons. They usually have overlapping scales and three pairs of gills. A series of bones called the operculum covers the gills and supports the face. The fin spines and rays are called lepidotrichia. Bony fish usually have swim bladders, which allow them to keep their place in the water without using their fins. One notable group of fish that do not possess swim bladders are lungfish.
Fossil Range Evolved in the Late Silurian.
Taxonomy Infraphylum: Gnathostomata
The taxon is paraphyletic: it does not include land vertebrates, which evolved from fish.
Mode of Life or Habitat Found in both marine and freshwater environments.
Adaptations Over Time Possibly evolved from early placoderms. Grew better at foraging and locomotion as time passed.
Distribution Worldwide.
Etymology The name is Ancient Greek for "bone fish," ὀστέον (ostéon, "bone") + ἰχθῡ́ς (ikhthū́s, "fish").
Additional Information Largest class/superclass of vertebrates extant today.
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Class Actinopterygii (ray-finned)

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Common Names Ray-finned fish
Physical Description Ray-finned fish are fish that have fins with webs of skin supported by bony/horny spines (called rays). They range from less than a centimeter long to around 12 meters.
Fossil Range Evolved during Late Silurian. The earliest known ray-finned fish was Andreolepis hedei, dating back 420 mya, found in Russia, Sweden, and Estonia.
Mode of Life or Habitat Seawater and freshwater at all depths. Most use external fertilization, with the female laying the eggs and then the male inseminating them. They feed on algae, diatoms, insects, and smaller fish.
Adaptations Over Time The swim bladder evolved into a more efficient organ in the teleost making them neutrally buoyant.
Distribution Worldwide.
Etymology New Latin actino- (possessing rays) + Ancient Greek πτέρυξ (ptérux, "fins").
Additional Information 99% of the over 30,000 species of fish extant. Largest class of vertebrates extant today.
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Genus Knightia

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Physical Description Resembles herrings. The size ranges from 6 cm to 15 cm, with some growing up to 25 cm (K. eocaena). Heavy scales and small, conical teeth.
Fossil Range (Late Cretaceous? to) Early Eocene, ~84-23.03 mya.
Taxonomy Order: Clupeiformes
Family: Clupeidae
Subfamily: Pellonulinae
Mode of Life or Habitat Freshwater lakes and rivers. Probably fed on algae and diatoms, and possibly insects and smaller fish. They traveled in large schools and so were a bountiful food source for predators.
Distribution North America and Asia
Etymology Named by David Starr Jordan in 1907 in honor of Wilbur Clinton Knight, a professor at the University of Wyoming.
Additional Information Knightia is the state fossil of Wyoming. It is the most commonly excavated fossil fish worldwide. Knightia is abundant in Wyoming's Green River Formation, and is often found being preyed on by larger fish fossils.
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Genus Xiphactinus

This fossil will only be tested at the State and National levels.

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Common Names X-fish. Bulldog fish.
Physical Description Approximately 5.1 m long with fangs and a distinctive underbite. It was the largest bony fish of the Cretaceous. The tail is forked, and attached to a narrow base. The jaw is very mobile, and therefore able to take in large prey. Its body is slender.
Fossil Range Cretaceous, ~112-66 mya. They died out during the Cretaceous-Paleogene extinction.
Taxonomy Order: Ichthyodectiformes
Family: Ichthyodectidae
Subfamily: Ichthyodectinae
Mode of Life or Habitat Shallow and deep marine. Very predatory, consuming fish, seabirds, and maybe pterosaurs. It was common for a dead or bleeding Xiphactinus fish to be eaten by sharks.
Distribution Kansas, the US east coast, Europe, Australia, Canada, Venezuela, and Argentina. During the Cretaceous, the American midwest was submerged under the Western Interior Sea.
Etymology Greek xiphos meaning sword + New Latin actino meaning ray.
Additional Information State fossil of Kansas. Often found with undigested/partially digested prey inside their stomachs. We do not know much about the larval and juvenile phrases of their life cycle. Republican Representative of Kansas Tom Sloan proposed that Xiphactinus be the Kansan state fossil in 2010, but it did not happen.
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Class Sarcopterygii (lobe-finned)

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Physical Description Their fins differ from those of all other fish - each is on a fleshy, lobelike stalk extending from the body.
Fossil Range Late Silurian to recent.
Mode of Life or Habitat They live in a combination of aquatic and terrestrial environments, hibernating while on land. They are ovoviviparous, and they have lungs and gills.

Genus Eusthenopteron

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Physical Description They were 5-6 feet long, and covered in scaly skin. Eusthenopteron had internal nostrils (called choanae), like tetrapods, as well as tetrapod-like teeth with enamel and a two-part cranium. The lepidotrichia cover all of its fins, and its fore-fin and pelvic fin endoskeletons resemble arms and legs respectively.
Fossil Range Late Devonian, 383.7-376.1 mya.
Taxonomy Clade: Tetrapodomorpha
Clade: Eotetrapodiformes
Family: Tristichopteridae
First described in 1881 by J. F. Whiteaves.
Mode of Life or Habitat They lived in shallow waterways, and preyed on smaller fish. Strictly aquatic, although it has a close relationship to tetrapods that made it onto land. Previously thought to have been one of the aquatic animals that started to make its way onto land. No larval stage has been found with evidence that it metamorphosizes into the adult Eusthenopteron, suggesting that it might hatch as an adult form.
Adaptations Over Time They have a close relationship to tetrapods. Earliest animal known to have bone marrow.
Distribution Quebec (Shore of River Ristigouche, Miguasha)
Etymology Greek: eustheno ("strength") + pteron ("wing"), possibly combining to form strongly developed fins.
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Genus Latimeria (Coelacanth)

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Common Names A genus of coelacanth. There are two extant species: the West Indian Ocean coelacanth (L. chalumnae) and the Indonesian coelacanth (L. menadoensis). In Indonesia, the Indonesian coelacanth is known as raja laut, king of the sea. In South Africa, Latimeria was termed gombessa or mame.
Physical Description They are approximately 2 m long and weigh 80 kg. Like all coelacanths, they have a three-lobed tail with the spinal column extending to the end of the tail (diphycercal). The West Indian Ocean coelacanth is deep blue while the Indonesian coelacanth is brown.
Fossil Range Middle Pleistocene (0.02 mya) to present-day.
Taxonomy Subclass: Actinistia
Order: Coelacanthiformes
Family Latimeriidae
Mode of Life or Habitat They are found in deep reefs and volcanic slopes in both freshwater and marine environments. They eat cuttlefish, squid, snipe eels, small sharks, and other fish. They give birth to live young (pups).
Adaptations Over Time One of the slowest evolving genomes of all known vertebrates. They are able to control the speed of their metabolism, achieving hibernation-like effects. Coelacanths can swim backwards and belly up in order to catch prey. Their eyes are very sensitive, which is why they are almost never found in daylight or well-lit water. Their eyes have an abundance of rods to detect objects in low light and a layer of tissue called the tapetum lucidum which helps night vision.
Distribution Indian Ocean (critically endangered) and Indonesia (vulnerable). The water must be cold and well-oxygenated. Usually live in depths of 90-200 m but can be found as deep as 700 m.
Etymology Coelacanth comes from Greek koilos ("hollow") + akantha ("spine"), referring to their unique hollow spine fins.
Additional Information Coelacanths are living fossils and were once thought to be extinct in the Late Cretaceous. As a whole, coelacanths are now extremely rare. Growth rings in the ears (calcium carbonate otoliths) indicate that they can live up to 80 to 100 years.
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Genus Tiktaalik

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Common Names Some people call Tiktaalik a "fishapod."
Physical Description 3 to 9 feet long. The eyes were on the top of the skull, rather than the sides. The shoulders were not connected to the skull, so it had a functional neck. They had "arms," including a shoulder, elbow, and wrist. Their skeletons could support their bodies.
Fossil Range Late Devonian, 383.7-376.1 mya.
Taxonomy Clade: Tetrapodomorpha
Clade: Eotetrapodiformes
Clade: Elpistostegalia
Clade: Stegocephalia
There is only one species: T. roseae.
Mode of Life or Habitat Lived in estuaries and deltas. They ate smaller fish and bug-like creatures. It is unlikely that they could live entirely on land. However, it is likely that they could cross dry land.
Adaptations Over Time They are an important transition fossil between fish and tetrapods.
Distribution Found in Bird Fiord, in Nunavut, Canada.
Etymology "Tiktaalik" is Inuktitut for "large freshwater fish."
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Class Amphibia (Amphibians)

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Common Names Amphibians
Physical Description Changes in anatomy allowed the upper body to be propped up for breathing, the head to turn, and created a rigid structure strong enough to support walking. Their eyes are larger than their predecessors because eyesight is more important on land than in water. They can weigh up to 500 pounds.
Fossil Range Evolved during the Late Devonian. Lost relevance to reptiles during the Carboniferous rainforest collapse and were hurt during the Permian-Triassic extinction.
Taxonomy Superclass: Tetrapoda
Mode of Life or Habitat Most undergo metamorphosis where the larva's gills are replaced by lungs. Amphibians need water bodies in order to reproduce. They are usually not found in the sea and live in moist habitats on land. Most amphibians are predators, eating almost anything that is swallowable and moves.
Adaptations Over Time They may have moved to land because of seasonal droughts and escape from drying pools, or maybe because they were carnivores and the land had a lot of arthropods which they could eat.
Distribution All continents except Antarctica.
Etymology "Amphibia" means "double life" and refers to a life cycle that includes an aquatic existence and a terrestrial existence.
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Genus Acanthostega

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Physical Description One of the first vertebrates to have recognizable limbs. They had eight digits on each hand linked by webbing. They lacked wrists and were generally unfit to come on land. They had both lungs and gills. About 0.7 m long and 10-20 kg. They had stubby legs. It had fish-like teeth and a lateral line organ (a system of epithelial cells, or hair cells, that detect movement in nearby water).
Fossil Range Late Devonian, 365 mya.
Taxonomy Clade: Tetrapodomorpha
Clade: Eotetrapodiformes
Clade: Elpistostegalia
Clade: Stegocephalia
Mode of Life or Habitat Rivers and shallow, weed-choked swamps. Probably ate fish. May have spent most of its time in shallow water.
Adaptations Over Time In general, they were poorly adapted for going on land (for example, joints were not very mobile, shoulder and forearm were very fish-like, ribs were too short to support the chest out of water). The eight digits on each hand perhaps indicates that Acanthostega may have been an evolutionary dead end.
Distribution Northern latitudes.
Etymology From Ancient Greek ᾰ̓́κᾰνθᾰ ákantha (“thorn” or “spine”) + στεγανός steganós (“roof”), combining to form “spiny roof”
Additional Information A famous fossil was found by Jennifer A. Clark in East Greenland in 1987, though fragments of the skull had been found in 1993 by Erik Jarvik and Gunnar Säve-Söderbergh.
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Genus Eryops

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Physical Description 1.5-2 m long but could grow up to 3 m. One of the largest land animals of its time. Adults were around 90 kg. Stout body with very wide ribs, a strong spine, four short and strong legs, a short tail, and a wide and elongated skull with many sharp teeth and strong jaws. Their skulls were broad and flat (2.0 feet or 60 cm long). Eryops had an unusually large skull and mouth with many curved teeth, with enamel in a folded pattern. The limbs were long and strong. The shoulder girdle is disconnected from the skull for improved terrestrial locomotion.
Fossil Range Late Carboniferous to Early Permian, 299-278 mya.
Taxonomy Order: Temnospondyli
Family: Eryopidae
Thought to have one species, E. megacephalus.
Mode of Life or Habitat Probably had similar hunting behavior to crocodiles, eating large fish and aquatic tetrapods. Habitat was lowland habitats in and around ponds, streams, rivers, and lakes. Juveniles probably lived in swamps which gave them protection from predators, while adults spent most of their time on land, although there was no sudden metamorphosis like with modern amphibians, instead slowly transitioning from aquatic larvae.
Distribution North America and western Europe. Mostly Texas (Permian) and New Mexico (Carboniferous).
Etymology Ancient Greek ἐρύειν, eryein (“drawn-out”) + ὤψ, ops (“face”) since most of its face is in front of its eyes.
Additional Information Skull and teeth are most common fossils, but several complete skeletons have been found.
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Genus Diplocaulus

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Physical Description The skull is shaped like a boomerang, possibly serving as a hydrofoil (helping Diplocaulus glide through the water) or as a defense mechanism. The bodies were stocky and salamander-like and reached 1 meter long, making them relatively large land animals for the time. They likely swam with an up and down movement like dolphins. Skulls are up to 40 centimeters wide across the horn tips. Their mouth gape was very small because the lower jaw hinge was posterior to the eye sockets. Diplocaulus is thought to have a long, thin tail that could curl up to reach the head, as in one fossil described in 1917, there were tail vertebrae next to the head. As a result, Diplocaulus is thought to have used anguilliform (eel-like) tail movement to propel itself.
Fossil Range Late Carboniferous to Late Permian, 306-255 mya.
Taxonomy Subclass: Lepospondyli
Order: Nectridea
Family: Diplocaulidae.
Mode of Life or Habitat Lived in rivers, lakes, and swamps. They ate insects and fish.
Adaptations Over Time Their head shape could have been defensive because predators would have a hard time trying to swallow such a large head.
Distribution North America and North Africa.
Etymology The name means "double caul" (the caul is the piece of membrane that covers a newborn's head and face.
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Class Reptilia (Reptiles)

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Common Names Reptiles.
Physical Description Reptiles have scales and dry, thin skin. They have either 0 or 4 legs. They have ear holes instead of ears. They range from 17 mm to 6 m in length. They have a 3-chambered heart with 2 atria, 1 ventricle, and 2 aortas. They use lungs to breathe.
Fossil Range Evolved during the Late Carboniferous (Pennsylvanian) and possibly the Early Carboniferous. They were dominant during the late Paleozoic and Mesozoic.
Taxonomy Superclass: Tetrapoda
Mode of Life or Habitat They are oviparous, and they shed their skin continuously throughout their lifetimes. Most are insectivorous or carnivorous.

Order Crocodilia (crocodiles)

This fossil will only be tested at the State and National levels.

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Order Testudines (turtles)

This fossil will only be tested at the State and National levels.

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Order Icthyosauria (Ichthyosaurs)

Picture(s) Ichthyosauria.jpg
Common Names Ichthyosaurs
Physical Description Eel-like, 1-16+ m long although they averaged 2-4 m. They had big eyes, the largest eyes of any reptile discovered. These large eyes support the hypothesis that ichthyosaurs underwent deep diving, since large eyes would have been useful for being able to see on deep dives. Later species were more dolphin-like (convergent evolution) than eel-like. Ichthyosaurs had elongated skulls and conical teeth, made of enamel and dentin, although teeth could also have cutting edges or crowns, depending on the species and its diet, e.g. shellfish-eaters versus fish-eaters. Many ichthyosaurs were heterodonts, with different tooth shapes in different parts of the mouth. Buoyant. Could swim up to 25 mph, making them perhaps one of the fastest marine reptiles to exist. The number of fingers varies by species, from two to up to ten per hand. The pelvis is loose, with the ilium, ischium, and pubic bone disconnected from each other. Possibly contained blubber (as evidenced by the 2018 discovery of Stenopterygius).
Fossil Range Early Triassic to Late Cretaceous, 250-90 mya. Most abundant in late Triassic and early Jurassic. Afterwards they were displaced by competition with plesiosaurs. Died out from the Cenomanian-Turonian anoxic event, which disturbed the oxygen and sulfur cycles in the ocean, as well as the carbon cycle, possibly from undersea volcanoes.
Taxonomy Subclass: Diapsida.
Although they were once thought to be amphibians, it is now agreed that they are reptiles and that they descended from terrestrial tetrapods.
Mode of Life or Habitat Carnivores. Wide range of prey, with different species having different diets, ranging from fish to cephalopods to birds to even smaller ichthyosaurs. Some ichthyosaurs crushed their prey with flat teeth, while others may have been suction feeders or used other methods. Ichthyosaurs gave birth to live young (i.e. they were viviparous), unlike terrestrial reptiles. Their sight was their most important sense: their hearing could have been poor. Ichthyosaurs may also have had electroreception capabilities. Ichthyosaurs were eaten by sharks and other ichthyosaurs, then by plesiosaurs and crocodilians after they evolved. It is thought that despite being a reptile, ichthyosaurs were warm-blooded (endothermic).
Adaptations Over Time Earlier species swam by moving their whole body from side to side (anguilliform motion), but later species swam moving only their tails (carangiform or possibly thunniform motion). Later species had paddle-shaped fins in place of forelimbs and hindlimbs (analogous structures with dolphin fins, although ichthyosaurs are not closely related to dolphins).
Distribution All Mesozoic oceans. Found in Europe, North America, South America, and Asia.
Etymology Ichthyosauria means "fish lizard." Named in 1821 by William Daniel Conybeare and Henry de la Beche.
Additional Information Hundreds of specimens recovered. Skin impressions through bacterial mats reveal the dorsal and caudal fins (which are not usually preserved). Many well-preserved fossils in Germany. One genus of ichthyosaur was found in the Solnhofen Limestone in Germany and seemed to show impressions of scales. Coprolites are common. Gastroliths are also sometimes found and may have helped with regulating buoyancy or digestion. It is debated whether ichthyosaurs had dorsal fins.
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Order Squamata

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Family Mosasauridae (Mosasaurs)

Picture(s) Mosasauridae.jpg
Common Names Mosasaur
Physical Description Could grow up to 17 m long. The largest known fossil on display is 13 m long and is named Bruce, displayed at the Canadian Fossil Discovery Center in Manitoba, Canada. However, some species were around 1 m long. Mosasaurs had black backs and white bellies, similar to modern great white sharks, as indicated by melanin concentrations. They were streamlined swimmers, and their tails ended in two crescent-shaped flukes. They had webbed paddles for limbs. Their jaws were double-hinged, meaning that they could extend their mouths to eat large prey whole. They do not have dorsal crests, although some popular images show them with dorsal crests, since tracheal cartilage fossils were mistaken for dorsal crests for a period. While they were originally thought to undergo eel-like motion, moving their whole body back and forth to swim (anguilliform motion), the discovery of tail flukes means that they likely used their tails for propelling their body instead. They had an expanded chest region, suggesting that they had 2 lungs.
Fossil Range Late Cretaceous, 101-66 mya. Dominant from the Turonian Age to the Maastrichtian. Died out in the K-T extinction.
Mode of Life or Habitat Carnivore, eating fish and ammonites for the most part, although some specimens were found with seabirds or smaller mosasaurs. Dominant predators. Lived in warm inland seas. Gave birth to live young (i.e., they were viviparous). Probably were warm-blooded, internally regulating their body temperature (endothermic).
Adaptations Over Time Mosasaurs evolved under a period of high productivity in the ocean. When productivity dramatically fell, mosasaurs went extinct.
Distribution Found worldwide: Europe, Australia, New Zealand, Africa, Japan, North America, and South America.
Etymology First fossils discovered in 1764 near the Meuse river, in a limestone quarry near the city of Maastricht, the Netherlands. Named by William Daniel Conybeare in 1822 after the Meuse river.
Additional Information There are many mosasaur specimens. The first mosasaur fossils were thought to be from a fish, then from a crocodile, then from a sperm whale. The scales are usually not preserved. However, some remarkably well-preserved specimens from Jordan show that mosasaurs had a pattern of diamond-shaped scales covering their body. It is possible that mosasaurs also had a snake-like forked tongue. Similarities in skulls, jaws, and scales suggest that mosasaurs are related to snakes.
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Order Plesiosauria (Plesiosaurs & Pliosaurs)

Picture(s) Plesiosauria.jpg
Common Names Plesiosaurs and pliosaurs
Physical Description 1.5-15 m long, averaging 14 m. Broad and flat bodies with four airfoil-shaped flippers and short tails. The tails had flukes. The flippers were used for propulsion (the usual claim is that they moved vertically in a "flying" motion rather than in a "rowing motion"), and the tail was used for steering. The flippers were large, around as big as the body, plesiosaurs had broad bone platse on their bottoms. Plesiosauromorphs have long necks and small heads while pliosauromorphs have short necks and long heads, although these do not imply a direct relationship: some members of the Plesiosauroidea clade are short-necked, and some members of the Pliosauroidea clade are long-necked. Their necks could have up to 70 vertebrae. The skull can be described as "euryapsid."
Fossil Range Late Triassic to Late Cretaceous, ~203.6-66.0 mya. Abundant during the Jurassic. Became extinct in the K-T extinction event.
Taxonomy Subclass: Diapsida
Mode of Life or Habitat Marine. Ate fish (piscivores). They gave birth to live young, unlike terrestrial reptiles. They may have been warm-blooded (endothermic). Plesiosaurs ate fish and cephalopods. Pliosaurs ate fish, cephalopods, sharks, ichthyosaurs, and even plesiosaurs.
Adaptations Over Time Early plesiosaurs lived closer to the shore.
Distribution Worldwide
Etymology Their name comes from the Greek plesios meaning "near to" and sauros meaning "lizard," since they are closer to lizards than ichthyosaurs.
Additional Information Have been found with gastroliths. Elasmosaurus is associated with the Pierre Shale in Kansas. It was first discovered in 1868 by Dr. Theophilus Turner and then sent to Edward Drinker Cope, who assembled the bones to form a long tail and short neck, mirroring modern lizards. This meant that the head was on the wrong end. A popular retelling has Othniel Charles Marsh, Cope's rival in the "bone wars," correcting Cope by placing it in the right place. However, it was likely actually Joseph Leidy in 1870.
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Order Pterosauria (Pterosaurs)

Picture(s) Pterosauria.jpg
Common Names Pterosaurs. Pterodactyls are a subgroup of pterosaurs, genus Pterodactylus.
Physical Description Some could grow up to 10-11 m and 250 kg, making them one of the biggest animals ever to fly. Some could be as small as 25 cm. Reptiles with wings made from skin and tissues going from an extended fourth finger to the ankles. They had hollow bones, a keeled breastbone, and an enlarged brain compared to its ancestors, all contributors towards the ability to fly. Many had webbed feet. Pterosaurs can be split into two groups, basal pterosaurs (also called non-pterodactyloids and rhamphorhynchus) and pterodactyloids. Basal pterosaurs were small with long tails and a wing that connected the two hind legs while pterodactyloids were more diverse and generally had narrower wings, small tails, long necks, large heads, and elongated skulls with horny beaked jaws. Pterodactyloids stood plantigrade on four limbs with their feet flat on the ground. Some pterodactyloids developed elaborate crest, displaying sexual dimorphism. Pterosaurs had pycnofibers (meaning "dense fibers") on their skin, analogous to mammalian hair, discovered by UV examination. These were about 5-7 mm long. Some speculate that pycnofibers and feathers derived from the same ancestral structure. Although in movies, pterosaurs are sometimes shown to grab prey with their feet, pterosaurs generally have no opposable toes, except for the genus Vesperopterylus, which is a small pterosaur. In Jurassic Park III, a toothless pterosaur genus was portrayed as teethed, with leathery wings instead of the more accurate taut skin membranes and an inaccurate nesting pattern.
Fossil Range Late Triassic to late Cretaceous. It was once thought that birds took the place of pterosaurs, but niche overlap seems to be minimal between the two groups.
Taxonomy More closely related to dinosaurs than to living reptiles. Likely evolved from archosaurs.
Mode of Life or Habitat Laid eggs. Hunted by theropods (a group of three-toed saurischian dinosaurs). Lived in a variety of environments. At first, pterosaurs were seen as fish-eaters, but today, many are thought to be omnivores, carnivores, or insectivores. Basal pterosaurs were likely effective climbers and may have lived in trees, eating insects or small vertebrates. Likely warm-blooded (endothermic), as indicated by the presence of a pycnofiber coat. Difference species can be diurnal, nocturnal, or cathemeral.
Distribution Worldwide.
Etymology From Greek pteron "wing" + sauros "lizard."
Additional Information They are the earliest vertebrates known with the ability of powered flight. Fossil eggs have been known to be found, the first of which was found in Liaoning. Baby pterosaurs are called flaplings, and it is likely that they were able to fly as soon as they hatched. Fossils are rare due to the hollow bones. Most specimens are found in Lagerstätten such as the Late Jurassic Solnhofen Limestone. Pterosaurs were first believed to be aquatic, with the wings mistaken as flippers. Found by Othniel Charles Marsh in the Niobrara Chalk in 1870, which was the first toothless specimen and whose skeletons were relatively complete, which allowed scientists to analyze the bone structure. In the late 1960s, interest in pterosaurs began to pick up again during an event known as the dinosaur renaissance, which painted dinosaurs as warm-blooded and highly active. Trace fossils show that at least some pterosaurs could run, wade, or swim.
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Clade Dinosauria (Dinosaurs)

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Common Names Dinosaurs
Physical Description Most dinosaurs had scaly skin with no hair. Carnivores had 2 legs, and herbivores had 4 legs.
Fossil Range Evolved during the Triassic. Non-bird dinosaurs went extinct in the K-T extinction.
Mode of Life or Habitat In the Triassic, they lived in riversides and scrublands. In the Jurassic, they lived in the forests. In the Cretaceous, they lived in swamplands, forests, mountains, and deserts.
Adaptations Over Time Slowly shrunk and grew feathers, evolving into birds.
Additional Information Interest in dinosaurs grew in the late 1960s, in a “dinosaur renaissance,” which theorized that dinosaurs were warm-blooded and therefore more active than previously imagined.

Order Saurischia (lizard-hipped)

Picture(s) Saurischia.jpg
Common Names Lizard-hipped dinosaurs
Physical Description The hips of dinosaurs are composed of the ilium, ischium, and pubis. In saurischians, the pubis is pointing forward at an angle to the ischium. This construction allowed for more surface area for muscle attachments and gave saurischians more support. Some other differences include a long neck, asymmetrical fingers, and grasping hands.
Fossil Range Separated from Ornithischia in the Middle Triassic. Extant as birds, with other theropods dying out in the K-T extinction.
Taxonomy The two major groups of saurischians are the sauropods (large herbivores) and the theropods (bipedal carnivores). While one might be inclined to think otherwise, birds descended from this order rather than Ornithischia.
Mode of Life or Habitat All habitats.
Etymology From Greek sauros "lizard" + ischion "hip joint."
Additional Information The hip structure of a dinosaur can affect movement and diet.
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Suborder Theropoda

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Physical Description A group of obligate bipedal (meaning they walked on two legs all the time) saurischian dinosaurs. They typically have hollow thin walled bones, as well as ziphodont (meaning serrated) teeth and claws at the end of all toes and fingers. They have an increased grasping ability and an intramandibular joint between their dentary and post dentary bones which probably acted as a shock absorber. An extra opening in the skull between the naris and the antorbital fenestra known as the promaxillary fenestra is also present in most (but not all) theropods. There are a few other distinctive traits:
  • Theropods (including birds) have a furcula, also known as a wishbone, that could have acted as a shock absorber
  • Theropods had at most four fingers.
  • Theropods had functionally tridactyl feet. This means that the 1st and 4th toes are reduced.
Fossil Range Evolved in the Late Triassic. Extant as birds, with other theropods dying out in the K-T extinction.
Taxonomy Birds descend from a clade of theropods called Coelurosauria.
Etymology From Greek thiríon “beast” + poús “foot.”
Additional Information Many theropods probably exhibited sexual dimorphism, typically consisting of two forms, gracile and robust. While scientists are still unsure, they believe that in most theropods the robust form (also known as a morph) represents the female, and the gracile represents the male.
Genus Allosaurus
Picture(s) Allosaurus.jpg
Common Names Allosaurus
Physical Description A bipedal theropod dinosaur that held its tail vertically outward to act as a counter balance. It had crests over its eyes, which are special growths of the lacrimal bone and were likely covered with a sheath of keratin. It had three large claws on the ends of each arm, which made up for its small bite force. Allosaurus could also open its jaw very wide, probably due to the lack of jaw muscles. It also had large olfactory bulbs, giving it a good sense of smell. Allosauruses have 9 vertebrae in their necks, 14 in their backs and 5 supporting their hips. They also had 3 fingers on their arms. Their skulls are 1 meter long, and they were around 8.5 meters long (some individuals approached 9.7 m, and some fragmentary specimens are interpreted as coming from animals 12 m long).
Fossil Range Late Jurassic (Kimmeridgian to Tithonian), 154-144 mya.
Taxonomy Family Allosauridae. Some synonyms are Antrodemus, Crocosaurus, and Labrosaurus. The type species is A. fragilis.
Mode of Life or Habitat They ate other dinosaurs (ornithopods). Paleontologists debate whether or not Allosaurus was a predator or scavenger. It seems that the consensus is that Allosaurus is a predator with a generalist approach (if it saw a carcass, it would eat it). It probably used its claws to help kill prey. Its jaws, while weak, were probably used to strip the flesh of of its prey causing it to die quickly due to blood loss (some evidence for this theory includes an Allosaurus skeleton with clear injury marks from the thagomizer of a Stegosaurus and the Cleveland-Lloyd Dinosaur Quarry where a group of Allosaurus fossils were found, this could be interpreted as group scavenging.
Distribution North America, Europe, Africa, and Australia. Many fossils are found in the Morrison Formation in the western United States.
Etymology Named by Othniel Charles Marsh in 1877. From Greek allos "different" + sauros "lizard" since it had concave vertebrae, which was different from any other dinosaur that was known at the time.
Additional Information It is likely that no other large theropod has more fossils discovered. Its reconstruction is beyond doubt.

Genus Coelophysis
Picture(s) Coelophysis.jpg
Common Names Coelophysis
Physical Description Coelophysis is an example of an early dinosaur. They are bird-like, with light and hollow bones. They are around 3 meters long and are fast with narrow hips and feet and two long legs. Their feet and hands have 3 digits and are clawed. They have long, pointed heads. There are two forms, robust (likely the male) and gracile (likely the female). This is called sexual dimorphism.
Fossil Range Late Triassic to Early Jurassic, around 216-196 mya.
Taxonomy Family: Coelophysidae.
There are a number of synonyms for Coelophysis, the most prominent of which is Rioarribasaurus. This is an example of a nomen rejectum‭ (‬meaning‭ "rejected name")‬. When paleontologists first discovered Coelophysis fossils in Ghost Ranch, they did not originally think that the fossils belonged to the genus Coelophysis. This was because they were in a much better condition than the holotype specimen. Eventually, paleontologists reclassified the fossils as belonging to Coelophysis, and as a result, the name Rioarribasaurus was retired.
Mode of Life or Habitat Lived in dry savannas. It is an opportunistic carnivore, eating small reptiles and fish. It was thought that coelophysis was cannibalistic due to the discovery of what initially appeared to be juveniles in an adult's stomach. However, upon reexamination, the remains are actually of a small reptile. Paleontologists have found groups of coelophyses gathered together but are unsure if this is indicative of herd behavior or just taking advantage of a food source.
Distribution Found worldwide. Most famously found in the Ghost Ranch Lagerstätte.
Etymology Means "hollow form." Named by Edward Drinker Cope‭ ‬in ‬1889.
External Links,Triassic%20and%20Early%20Jurassic%20formations.
Genus Deinonychus

This specimen is not on the official 2020-2021 Fossil List but has been on the Fossil List in the past.

Picture(s) No pictures have been added as of yet.
Physical Description Deinonychus has a curved, flexible neck and a big head with serrated teeth. It has three-fingered hands with sharp, curved claws. It also had a four-toed clawed foot with the second toe having a 12 cm sickle-like claw. It is around 3 m long, 1.5 m tall, and around 1 m tall at the shoulder. It has a relatively large brain (with a high EQ of around 5.8) with large, keen eyes.
Fossil Range Middle Cretaceous, around 110-100 mya.
Taxonomy Family: Dromaeosauridae
Mode of Life or Habitat Forests. Opportunistic carnivore: ate anything it could tear apart.
Distribution Western US.
Etymology Means "terrible claw."

Genus Dilophosaurus
Picture(s) Dilophosaurus.jpg
Common Names Dilophosaurus
Physical Description This dinosaur is probably best known for the two bony crests on top of its head. These crests were elongations of the antorbital fenestra and were filled with air sacs which would have lightened and strengthened it. The crests would also likely have been covered by keratin, making them larger in life than in fossils. While famous movies (e.g. Jurassic Park) may depict them as having frills and venom, this is likely not the case. Its hand had four fingers, but the fourth finger was merely vestigial.
Fossil Range Early Jurassic, around 196-183 mya.
Taxonomy Family: Dilophosauridae
Mode of Life or Habitat Dilophosaurus was a predator. It is thought that it may have eaten fish, as its jaw and dental structure is similar to that of a modern gharial.
Distribution Known from the Kayenta Formation, in states such as Arizona, Utah, Colorado, and New Mexico.
Etymology Means "two-crested lizard." Named in 1970 by Samuel P. Welles.
Additional Information There have been many recent discoveries and competing theories about the use of the two crests, as well as Dilophosaurus's niche. Scientists hypothesise that the crest could have been used for mating displays as well as a way for individuals to recognize each other. Much of the confusion regarding the niche of Dilophosaurus stems from the fact that the original specimen was incomplete. More complete specimens show a robust skull as well as special ridges for muscle attachment that are present in modern day reptiles, which would increase the bite force. There is also evidence that Dilophosaurus's respiratory system allowed for unidirectional flow: this indicates that it had high metabolism levels and thus high activity levels, portraying it as a hunter rather than a scavenger. Fossils of infants, footprints, and resting traces have all been found. It is the state dinosaur of Connecticut.
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Genus Spinosaurus

This fossil will only be tested at the State and National levels.

Picture(s) Spinosaurus.jpg
Common Names Spinosaurus
Physical Description Spinosaurus is probably best known for the sail on its back. However, it exhibits several other less flashy yet important features. It had a long snout with unserrated teeth. Spinosaurus had three fingers and a dense bone structure.
Fossil Range Late Cretaceous, 99-93.5 mya. An explanation for its extinction could be that it became much too specialized for its niche, and when its optimal environment was destroyed or when it faced competition from more generalist theropods, it would have eventually been driven to extinction.
Taxonomy Family: Spinosauridae
Mode of Life or Habitat Predator. Probably lived in a semi aquatic environment.
Adaptations Over Time Had a long paddle like tail, indicating that it likely lived in an aquatic environment and used its tail to propel itself through water.
Distribution North Africa,‭ ‬particularly Egypt (Bhariya Formation)‭ ‬and Morocco (Kem Kem Beds).
Etymology Named by Ernst Stromer‭ in 1915. Means "spine lizard."
Additional Information The first specimen was only known by a few bones and was destroyed during WW2. More complete specimens were only found recently (in the 2000s). The purpose of Spinosaurus's sail is still debated, but there are a few popular theories:
  • The sail could have been used for thermoregulation: this is fairly controversial, as it does not explain size differences between individuals. A slightly more probable explanation is that Spinosaurus's sail could have served to counter the water's cooling effect (since it stood in the water all day) and catch sunlight.
  • The sail could have been used to support a hump for fat storage, similar to the hump of a modern-day camel.
  • The sail could have been used as a mating display. This could work in conjunction with the hump of fat theory: the larger the hump, the more successful at catching prey the dinosaur was.
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Genus Tyrannosaurus
Picture(s) Tyrannosaurus.jpg
Common Names Tyrannosaurus
Physical Description Tyrannosauruses are 12 m long and 5 m tall (4 m at the hips). They had huge skulls (1.5 m long) at the ends of short and muscular S-shaped necks and long and heavy tails as a counterbalance. The arms were short. They had two clawed fingers and a small metacarpal. Their feet are bird-like with three clawed toes and a metatarsus. Tyrannosaurus bones are hollow, like birds. Tyrannosaurus had a bite force of 35000-57000 newtons (7900-13000 lbs). There are two different morphs of tyrannosaurs, robust and gracile. These morphs suggest that tyrannosauruses exhibited some form of sexual dimorphism, with females being larger, as they needed a larger pelvis to lay eggs. Scientists think that tyrannosauruses probably had some form of primitive feathers. They also had large olfactory bulbs, which means that they had a good sense of smell. This could have been used to sniff out carcasses. There are small holes on the upper and lower jaws of the skull known as foramina. These are common in theropod dinosaurs and could indicate the presence of a sensory organ such as lips.
Fossil Range Late Cretaceous, 85-65 mya.
Taxonomy Family: Tyrannosauridae
Some scientists classify species from the genus Tarbosaurus ("terrible lizard") as part of Tyrannosaurus.
Mode of Life or Habitat It is debated whether tyrannosauruses were scavengers, active hunters, or a combination of the two. Likely fed on hadrosaurs, ceratopsians, and ankylosaurs. May have eaten Tyrannosaurus carcasses. Lived in the coastal plains of Larimidia, which was the western half of the United States, separate from Appalachia.
Distribution Western North America
Etymology Means "tyrant lizard." T. rex means "tyrant lizard king." Named in 1905 by Harry Osborn, although it was discovered by Barnum Brown.
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Genus Velociraptor
Picture(s) Velociraptor.jpg
Physical Description Around 1.5 m long and 1 m tall, with a long, flat snout. Their head is 18 cm long, and their neck is S-shaped. They have three clawed fingers and four clawed toes. Their legs are long and thin, and they have a stiff tail containing fused bones for counterbalance. They could run 60 km/h in short bursts. Velociraptors are feathered and bipedal with an enlarged sickle shaped claw, likely used to help kill its prey. Although featured in Jurassic Park, the movie’s adaptation of velociraptors was likely based on the genus Deinonychus. The teeth and jaws of velociraptors are small and were likely unable to kill. The scleral rings (which support the eyes) have been compared to modern birds and indicate that velociraptors are probably nocturnal.
Fossil Range Late Cretaceous, around 85-80 mya.
Taxonomy Family: Dromaeosauridae
Mode of Life or Habitat Lived in hot, dry environments with streams. There is little evidence showing that velociraptors hunted in packs. However, some of their close relatives might have. Velociraptors were probably warm blooded since they had feathers and needed a fast metabolism to be hunters.
Distribution Mongolia (Barun Goyot Formation and Djadochta Formation), China, and Russia.
Etymology From Latin for "swift thief." Named by Henry Fairfield Osborn in 1924.
Additional Information One famous fossil involves a velociraptor fighting a protoceratops.
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Suborder Sauropodamorpha

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Common Names Sauropods
Physical Description Herbivorous dinosaurs characterized by small skulls, long necks, and (at least ancestrally) leaf-shaped teeth. Many of them also have a very large and strongly rotated manual digit I. Later sauropods may have even had a small fleshy cheek. Here are some other features:
  • The presence of large nares.
  • The distal part of the tibia is covered by an ascending process of the astragalus.
  • Their hind limbs are short when compared to their torso length.
  • The presence of three or more sacral vertebrae
  • The presence of 25 presacral vertebrae
Fossil Range Late Triassic to Cretaceous.
Mode of Life or Habitat This is one of the rare examples where an organism evolves herbivory (this means that its ancestors were originally carnivores). Another dietary behavior some sauropods had is known as bulk browsing. This is the biting off and swallowing of large quantities of food without chewing, letting the gizzard grind them up. To facilitate this, the cheeks are lost, and a wide gape and tooth-to-tooth occlusion is evolved. This is present in gravisaurs. By comparing the scleral rings (used to support the eyes) in sauropodomorphs and modern day birds, scientists have concluded that sauropodomorphs were likely cathermal (active during the day for short intervals).
Etymology Means "lizard-footed forms." Originally established by Friedrich von Huene in 1932.
Additional Information The evolutionary trend of gigantism is seen in sauropodomorphs. Early sauropodomorphs are relatively normal sized while core sauropodomorphs and near sauropodomorphs were much larger (3-8 m and 10+ m respectively). Supergiants occur independently in many different genera.
Genus Apatosaurus

This specimen is not on the official 2020-2021 Fossil List but has been on the Fossil List in the past.

Picture(s) No pictures have been added as of yet.
Common Names Apatosaurus
Physical Description Apatosauruses have sturdy legs, and their hind legs are larger than their forelegs. Their forelegs had 1 claw, while their hind legs had 3 claws. They have slim tails, and their vertebrae have enormous spines. Their heads and brains are relatively small.
Fossil Range Late Jurassic, around 157-146 mya.
Taxonomy Infraorder: Sauropoda
Family: Diplodicidae
Distribution North America
Etymology Means "deceptive lizard," as apatosaurus bones have been mistaken for mosasaur bones.
Additional Information When an Apatosaurus skeleton was put together with the head of a camarasaurus, the "new" dinosaur was mistakenly named Brontosaurus ("thunder lizard") by Othniel Charles Marsh. The mistake was soon discovered.
Genus Brachiosaurus
Picture(s) Brachiosaurus.jpg
Common Names Brachiosaurus
Physical Description Brachiosauruses were long-necked quadrupedal sauropods. Their front legs were much longer than their hind legs, and they had chisel-like teeth. They had a claw on the first toe of each front foot and claws on the first three toes of each rear foot. They also had small heads, reducing the amount of effort required to lift the head. In addition, Brachiosaurus had a complex system of air sacs to lighten its long neck. Had 52 teeth. Because of their long necks, brachiosauruses probably had an extremely high blood pressure of over 400 mmHg.
Fossil Range Late Jurassic, 154-153 mya.
Taxonomy Family: Brachiosauridae
Mode of Life or Habitat May have been gigantothermic, meaning it was easier for brachiosauruses to maintain a constant and very high body temperature because of the small surface area to volume ratio. Estimated to have had an internal temperature of 38.2 degrees Celsius. May have travelled in herds.
Distribution North America (especially the Morrison formation in the western United States) and Africa.
Etymology Means "arm lizard." Named by Elmer S.‭ ‬Riggs in 1903. First found in the Colorado River valley.
Additional Information Their size was their primary defense mechanism. Their tails could also have caused severe damage. One interesting flaw in Brachiosaurus’s body design was that if a brachiosaurus ever fell over, the impact might have killed it. They laid eggs but did not provide care. One major question about reproduction is how brachiosauruses laid eggs without breaking them. It has been proposed that they used tubes that extended from their bodies like modern-day turtles.
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Genus Diplodocus
Picture(s) Diplodocus.jpg
Physical Description Long neckedd qaudrupedal herbivorous sauropod dinosaur. Its front legs were shorter than its back legs and had a row of spines running down its back. Its nostrils were at the top of its head and it had peg-like teeth. They also had Gastralia- or hanging belly ribs- these are not actual bone rather ossified abdomen muscles. It was about 24 m long. They had an extremely long tail which had 80 vertebrae
Fossil Range Mid to Late Jurassic
Etymology double beamed, referring to the double-beamed chevron bones located in the underside of the tail named by Marsh‭ ‬-‭ ‬1878 but discovered by S. W. Williston in 1877
Additional Information Stripped leaves of off branches, this behavior is shown by its outward pointed teeth and that teeth are only present in the front of the mouth. Has been called the longest dinosaur that ever lived, but that may no longer be accurate. It is easy to confuse Diplodocus with brachiosuarus, one main difference is that the hind legs of diplodocus are longer than its fore leimbs but in brachiosaurus it is the other way around. The assumption that diplodocus used its long neck to reach leaves high up is false, as this would have placed extreme pressure on their blood vessels. Instead they likely held their neck out horizontally and swung it back and forth to feeed on lower vegetation. It has also been suggested that the long neck was a mating adaptation. Diplodocus had no known predators as an adult but juveniles were likely subject to predation. Their long tails could have been used for defense or as a signalling device. May have had an ovippositor to lay eggs. Their eggs were small compared to thei size, this was probably meant to make the incubation time shorter so the eggs were less susceptible to predators.
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Genus Patagotitan

This fossil will only be tested at the State and National levels.

Picture(s) Patagotitan.jpg
Physical Description A quadripedal sauropod dinosaur with a smalll head, large nostrils, and hollow bones. It could grow up to 37 m and have a mass of 55-57 tons. There are three distinguishing features of Patagotitan:
  1. It had something called lamina prezygapophysis on its first three dorsal vertebrae. These were extra rigdes running along the side of the vertebrae.
  2. The first caudal vertebrea is flat in front and convex in the back
  3. Some vertebrea have vertical neural spines
  4. Some neural spines show bifurcaion(they split down the middle) this is thought to be an adaptation unique to some sauropod dinosaurs to help support the increasing weight from thei horizontall cervical columns(neck).
  5. They also have a special rigde at the front of the 3rd and 4th dorsal vertebrae as well as a special indent in the back of each one this feature is collectively known as the hyposphene-hypantrum. This feature is also seen in other archosaurs and is meant to increase back rigidity.
Fossil Range Late Cretaceous
Distribution Argentina,‭ ‬Chubut Province‭ ‬-‭ ‬Cerro Barcino Formation
Etymology Named after where it was found (patagonia) as well as the titans from greek mythology which symbolize strength
Additional Information There is only one species in this genus: Patagotitan mayorum. Might have been the largest land animal ever.
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Genus Plateosaurus
Picture(s) Plateosaurus.jpg
Physical Description Plateosaurus is a basal or early sauropod(prosauropod), this means that many behaviors/features commonly associated with sauropods are missing. It is bipedal and even though its skull is small, similar to other sauropods, its neck is not nearly as long(only 10 cervical vertebrae) it also had 40 caudal vertebrae. It has grasping hands with three fingers and large claws, possibly used for feeding or defense. Individual skulls have a large range of sizes indicating that their growth was individual, fluctuating based on resources and the surrounding environment, this is also known as developmental plasticity and is seen in many modern day reptiles. It was digitigrade, meaning it walked on its toes like cats. Its eyes were on the side of its hea to enable a greater field of vision to watch for predators. The resperatory system was an important discovery for scientists. It was found that plateosaurus had a respiratory system similar to birds where air sacs push into the bone to decrease weight (also known as postcranial pneumaticity). This is the adaptation that allowed later sauropods to grow so large. An important feature Plateosaurus shares with other sauropods is its crowned teeth, meant to feed on plants.
Fossil Range late Triassic
Taxonomy Chordata,‭ ‬Reptilia,‭ ‬Dinosauria,‭ ‬Saurischia,‭ ‬Sauropodomorpha,‭ ‬Plateosauridae
Distribution Europe, North America, Greenland‭ ‬-‭ ‬Fleming Fjord Formation.
Etymology Described by Christian Erich Hermann von Meyer‭ ‬-‭ ‬1837, discovered in 1834 by Johann Friedrich Engelhardt name means broad lizard
Additional Information Was capable of walking quadrepedally, for a slow gate, and bipedally for a faster gate. Unlike mammals when Plateosaurus wanted to move faster it relied on either lengthening its stride. The growth of plateosaurus is also unusual. It continued to grow even after sexual maturity, and only stopped when it reached its maximum size, this is known as determinate growth. Were probably cathermal, active for short periods of time during the day and night, and endothermic (from the microstructure in the bones).
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Order Ornithischia (bird-hipped)

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Physical Description Ornithischia is an order of dinosaurs classified by the orientation of their hip bones. In Ornithischian dinosaurs the structure resembles that of modern birds-- but be careful as this does not mean that birds evolved from ornithischian dinosaurs. In ornithischians the pubis bone is parallel to the ischium, this arragnement provided more room for the intset\stines, an important feature in herbivorous dinosaurs. In addition, Ornithisians had a wider pelvis, for more stability, a smaller antorbital fenestra (opening in the skull), and were for the most part herbivores.
Etymology "bird-hipped"- Harry Seeley 1887
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Infraorder Anklyosauria

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Physical Description Ankylosaurs are more focused on passive defense adaptions than other armored dinosaurs, like stegasaurs. They are characterized by Osteoderms, or scutes, fused to the skull roof, osteoderms covering the neck and shoulders as well as extensively covering their backs, and for being wider than they were tall (an unusual construction in dinosaurs).
Fossil Range First appear in the jurassic but are rare, become much more common during the cretaceous
Adaptations Over Time They could breathe while chewing. Reduced predentary bone allowed them to more efficiently chew their food, this is an example of convergent evolution as it also appears in other ornithopods. Ankylosaurs also had strong, specialized tongues.
Etymology named by Osborn in 1923.
Additional Information The most famous feature of Ankylosaurs is their osteoderms, which are similar to modern day crocodiles. These osteoderms were composed of a thin outer layer of compat bone and were filled with spongy bone.They may have also been covered in keratin, which does not fossilize well.
Genus Ankylosaurus
Picture(s) Ankylosaurus.jpg
Physical Description Was heavily armoured with osteoderms fused to its skin (hence the name), it even had bony plates over its eyelids. It had two triangular horns on its head and two ridges of spines running down its back. It also had a tail club made out of osteoderms fused to the end vertebrae. This was probably used as defense against predators and for defense of their territory. The only place that ankylosaurus was vulnerable was its stomach, which did not have any osteoderms. It had 72 to teeth that were leaf shaped and not meant for grinding as they probably did not eat large plants.
Fossil Range Late Cretaceous
Distribution Western North America,South America, Alberta - Horseshoe Canyon Formation, Scollard Formation. USA, Montana - Hell Creek Formation, New Mexico - Kirtland Formation, Wyoming - Ferris Formation, Lance Formation
Etymology Barnum Brown‭ ‬-‭ ‬1908, "fused lizard"
Additional Information To sustain itself ankylosaurus probably had to eat large amounts of plants, in order to digest all of tis food ankylosaurus probably used fermentation to break it down.

Infraorder Ceratopsia

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Genus Triceratops
Picture(s) Triceratops.jpeg
Physical Description It has three horns on its face, and was a quadripedal herbivore. One of its horns was above its beak, and the other two are located above its eyes. Some species have epoccipitals‭ -pointed bones-on the edge of its frill. The fingers on Ceratopsians fore feet are pointed outwards to the sides, instead of facing foreward like in sauropods, ankylosaurs, and stegosaurs this indicates bipedal origins. They also had two vestigial digits on their hads (4 and 5) and the number of bones in their hands is:3-4-3-1. The frills of triceratops are made up of metaplastic bone, which means that they change shape as the dinosaur grows. Another special feature of Triceratops where their teeth. Their teeth were arranged into groups called batteries and were continually replaced throughout their lifetime, explaining why they are such common finds. they are perhaps one of the most complicated teeth in the animal kingdom, they had fovee layers which, over time, wore down at a point(like a sword), which decreased friction between them and allowed for a slicing rather than grinding motion. This may have allowed triceratops to expand into other niches and become more successful. Triceratops probably did not have a very good sense of smell
Fossil Range Late Cretaceous went extinct in the Cretaceous–Paleogene extinction event
Distribution USA,‭ ‬Colorado,‭ ‬Montana,‭ ‬South Dakota,‭ ‬Wyoming.‭ ‬Canada,‭ ‬Alberta,‭ ‬Saskatchewan
Etymology named by Marsh‭ ‬-‭ ‬1889, means: tri-, from Latin meaning three, cerat-, from Greek meaning horn, -ops, from Greek meaning face gives the name for Triceratops, a dinosaur with a three-horned face
Additional Information Fun fact: Marsh named the first triceratops skeleton Bison alticornis because he thought that it was a species from extinct bison from the Pliocene (we all make ID mistakes sometimes!) There is a debate about what the purpose was of triceratops' horns. The most well known and well supported argument is that their purpose was for defense against predators and its own kind, however, while this theory is still widely accepted there are some issues. Mainly the fact that the horns are highly variable among species, had their only purpose been defense this would have not been the case(they would be designed for efficacy not show) this is also the logic used to dismiss theories pertaining to thermal regulation. Other theories have been proposed that work in conjunction with the defense theory:
  • Were used to identify individuals in certain species
  • Had impressions of blood vessels so could have changed colors with increased blood flow and have acted as a signaling device.
  • It is also possible that these horns were indicative of some form of sexual dimorphism

The next point of controvercy is the debate over herd behavior. The supporting evidence for herd behavior is:

  • current day large herbivores exhibit this behavior
  • Triceratops were very common during their time- very likely to come into contact with one another
  • would have provided protection against predators that would have been dangerous to a lone triceratops

Genus Protoceratops

This fossil will only be tested at the State and National levels.

Picture(s) Protoceratops.jpg
Physical Description Quadrupedal dinosaur with neck frill and a beaked mouth. were not very large. Are sometimes referred to as the "sheep of the Mesozoic". Around 1.8 M long and 400kg.
Fossil Range Late Cretaceous
Taxonomy Dinosauria, Ornithischia, Genasauria, Cerapoda, Marginocephalia, Ceratopsia, Neoceratopsia, Coronosauria
Adaptations Over Time The frills were likely used for mating purposes as they were fragile. Some other rejected theories are that it was used for protection or an anchor point for neck muscles. it had powerful jaws and teeth in the back of its mouth enabling it to eat plants more efficiently.
Distribution Mongolia in the Gobi Desert, Djadochta Formation
Etymology "first horned face" in Greek, was named by Walter W.‭ ‬Granger‭ and ‬William King Gregory‭ ‬in‭ ‬1923, but was first found by James Blaine Shackelford in 1922.
Additional Information Probably cathermal, or active for short irregular periods of time. Large numbers of fossils found close together are taken as evidence for herd behavior. Males had larger frills than females (sexual dimorphism). Were early ancestors of Triceratops

Infraorder Ornithopoda

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Genus Iguanodon
Picture(s) Iguanodon.jpg
Physical Description Iguanodon was a large herbivore that was able to shift between bipedal and quadrupedal stances. On average, Iguanodon was 10 meters long and weighed about 3 tons. They had beaked mouths and their thumbe were composed of a modified claw, likely used for protection or foraging. The fifth digit(the pinkie) was extremely flexible, one possible purpose of this finger was to grasp branches. The middle three digits were inflexible and were meant to bear most of the weight.
Fossil Range mid Jurassic to Early Cretaceous
Taxonomy Animalia, Chordata,‭ ‬Reptilia,‭ ‬Dinosauria,‭ ‬Ornithischia,‭ ‬Ornithopoda, iguanodontidae, Iguanodon
Mode of Life or Habitat Herbivore
Etymology Named by Gideon Mantell‭ ‬-‭ ‬1825, Discovered by William Harding Bensted, means 'iguana-tooth'
Additional Information In early reconstructions the Iguanodon's thumb spike was placed on its snout. In addition, these reconstructions depicted Iguanodon as a tail dragger. In reality, this would not have been anatomically possible because the tails of Iguanodon were made of ossified bones-- bones that turned to bone during development-- and would have had to be held horizontally.
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Genus Parasaurolophus
Picture(s) Parasaurolophus.jpg
Physical Description Parasaurolophus was a herbivore dinosaur that was both biped and quadruped. One of the most striking features is its crest. The average weight is 2.5 tons and the estimated length 9.5 m. They exhibit sexual dimorphism, which is shown in their crest size.
Fossil Range Late Cretaceous
Taxonomy Animalia, Chordata,‭ ‬Reptilia,‭ ‬Dinosauria,‭ ‬Ornithischia,‭ ‬Hadrosauridae,‭ ‬Lambeosaurinae
Adaptations Over Time There are many theories about the purpose of the crest, however many have been debunked. The most popular ones include:
  • Thermoregulation- If this was truly the case it still would not explain the major differences in crest shape in between species
  • Visual recognition- this theory would explain variations in crest shapes
  • amplifying sound for communication- this theory suggests that the crest was a resonance chamber used to amplify calls. An interesting observation is that the crests of females are differently shaped than those of males so they could have had the ability to make lower and louder calls. It is estimated that typical calls rage between frequencies 55 and 720 Hz.

Its jaws were well suited for chewing pine cones and pine needles.

Distribution Have been found in the Fruitland Formation of New Mexico and the Dinosaur Park Formation in Alberta
Etymology meaning "near crested lizard" in reference to another dinosaur, Saurolophus. Named By William Parks‭ ‬-‭ ‬1922.
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Genus Maiasaura
Picture(s) Maiasaura peeblesorum cast - University of California Museum of Paleontology - Berkeley, CA - DSC04688.JPG
Physical Description Maiasaura is a herbivorouse duck-billed dinosaur capable of wlking both bipedally and quadrupedally. Juveniles were mainly bipedal, while the heavier adults were mainly quadrupedal.
Fossil Range Late Campanian of the Cretaceous
Taxonomy Chordata,‭ ‬Reptilia,‭ ‬Dinosauria,‭ ‬Ornithischia,‭ ‬Ornithopoda,‭ ‬Hadrosauridae,‭ ‬Saurolophinae,‭ ‬Brachylophosaurini
Distribution North America (USA, Montana)Two Medicine Formation
Etymology Name means "Good mother lizard" coming from Greek and Latin, Named By: Jack Horner‭ & ‬Robert Makela‭ ‬-‭ ‬1979
Additional Information Fossils of Maiasaura eggs as well as juvenile Maiasaura have shown that they are born with underdeveloped hind legs and require care from their mothers, hence the name. They could lay 30-40 eggs in one nest and gathered in large hers when nesting. They could run to escape predators, but only in short bursts. They could eat 200 lbs of food every day.

Infraorder Pachycephalosauria

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Genus Dracorex
Picture(s) Dracorex.jpg
Physical Description Dracorex wea a bipedal and proabaly herbivorous dinosaur, despite its serrated teeth. Dracorex had flat skull with distinctive horns. The flat skull is a subject of controversy among paleontologists. It has led some to believe that Dracorex is the juvenile form of another pachycephalosaur, Pachycephalosaurus. This is because it is believed that their flat heads became domed as they matured.
Fossil Range Late Cretaceous
Taxonomy Kingdom: Animalia, Phylum: Chordata, Class: Reptilia, Order: Ornithischia, Family: Pachycephalosauridae
Distribution Hell Creek formation
Etymology Named by R.‭ ‬T.‭ ‬Bakker‭ ‬-‭ ‬R.‭ ‬M.‭ ‬Sullivan,‭ ‬V.‭ ‬Porter,‭ ‬P.‭ ‬Larson‭ & ‬S.‭ ‬J.‭ ‬Saulsbury‭ ‬-‭ ‬2006. Means "The dragon King" in greek. The only known species, Dracorex hogwartsia name means "the dragon king of hogawarts"
Additional Information Its main defense againt predators was its speed.

Infraorder Stegosauria

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Genus Stegosaurus
Picture(s) Stegosaurus.jpg
Physical Description Stegasaurus was a quadrupedal herbivorous dinosaur with a line of dermal plates running down its back, also referred to as osteoderms. Stegasaurus aslo had spikes on its tail, which are known as the thagomizer and were likely used for defense. Its forelimbs were shorter than its hind limbs, as a result it was slow and its tail was probably held at an upward angle. Could be 9 m in length and 5-7 tons. They had no teeth at the front of their mouths, instead, a beak to help them graze on vegetation.
Fossil Range Late Jurassic
Taxonomy Kingdom: Animalia, Phylum: Chordata, Class: Reptilia, Order: Ornithischia, Family: Stegosauridae
Adaptations Over Time There were between 17-22 plates on Stegasaurus' back they were probably covered in a keratenous sheath. Their purpose is still debated some theories include:
  • Mating
  • Thermoregulation
  • Protection
Distribution Morrison Formation. Portugal - Alcobaça Formation
Etymology First described by Marsh in 1877 during the Bone Wars. Means 'roof lizard' in Greek, it was called this because Marsh originally believed the bones veolnged to a turtle.
Additional Information IT has taken scientists a while to settle on the current plate formation which hs two rows of alternating plates. Stegasaurus is known for having an extremely small brain, often described as the size of a walnut. At one point paleontologists believed that Stegasaurus had a second brain next to its hip. This region, known as the sacro-lumbar expansion, is present in birds and actually contains something know as the glycogen body.
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Class Aves (Birds)

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Genus Archaeopteryx

Picture(s) Archaeopteryx.jpg
Physical Description A feathered dinosaur that could be the size of a bluejay to a chicken. Looked similar to a theropod other than the fact that it had feathers. It had several characteristics that it shared with modern day birds including: An airfoil wing with contour feathers and a furcula (wishbone). Some more reptilian characteristics include: A full set of teeth, a long bony tail, a wing claw. Archaeopteryx is an extremely important transitional fossil, meaning that it show the evolutionary forms that occured between birs and dinosaurs. was approximately 20 inches, and weighed 1.8 to 2.2 pounds.
Fossil Range Late Jurassic
Taxonomy Phylum: Chordata, Class: Aves, Order: Archaeopterygiformes, Family: Archaeopterygidae
Mode of Life or Habitat Probably ate insects
Distribution Europe, specifically Solhofen Germany
Etymology Urvogel in German meaning, "first bird". Archaeopteryx comes from Greek and means "old wing"
Additional Information Archaeopteryx was capable of flight, however it was not very good and differed greatlyfrom modern birds. THe rounded edges of its wings are similar to modern day birds found in forested environments, suggesting that thai salso where Archaeopteryx lived. Archaeopteryx could suppot both the "trees down" or the "ground up" evolution of flight. Scelral ring comparison leads scientists to think that Archaeopteryx was diurnal. Archaeopteryx also did not have a reversed toe, so it could not hold on to branches like modern birds.

Genus Titanis (Terror Bird)

Picture(s) Titanis.jpg
Physical Description Large flightless carnivore bird. It could reach heights of about 2.5 meters and usually weighed around 150kg. It can most easily be recognized by its large skull and hooked beak.
Fossil Range Pliocene-Early Pleistocene
Taxonomy Kingdom: Animalia, Phylum: Chordata, Class: Aves, Order: Cariamae, Family: Phorusrhacidae
Distribution North America, USA,‭ ‬Florida,‭ ‬Texas, was the only known terror bird to have lived in North America.
Etymology Titanis refers to theTitans from greek mythology.
Additional Information IT is thought that Titanis used its large beack and talons to pummel its prey to death, this is seen in its modern day relatives, Seriemas. Their skull bones were also fused together, suggesting that they used their beacks to kill their prey as well. Titanis also had very long legs, as a result they had a digitigrade stance, which meant that they stood on their toes and not the bottoms of their feet. The Terror Bird's original range was in South America however, it migrated to North America during an event known as the Great American Biotic Interchange (GABI) when terrestrial connection was formed in between North and South America. They then had to compete with all of the North American carnivores for resources. However, the primary cause of extinction probably had o do with climate change altering ecosystems from forests to grasslands making it harder for Titanis to stalk its prey.

Genus Icthyornis

This fossil will only be tested at the State and National levels.

Picture(s) Ichthyornis.png
Physical Description Icthyornis is an important fossil for describing the evolution of birds. It was 24cm long and had a wingspan of 43 cm. Unlike modern birds Icthyornis had teeth at the center of its mouth, the rest of its beak was made up of many different bony plates, similarlly to an albatross.
Fossil Range Late Cretaceous Period
Taxonomy Chordata, Aves, Ichthyornithes, Ichthyornis
Adaptations Over Time Scientists have been able to infer from its breastbone, which is similar to modern day birds, that Icthyornis was probably a good flyer. They also had fused metacarpals which allowed for more precision.
Distribution Niobrara Formation and the Greenhorn Limestone formation in Kansas, It is present in layers that come from the Western Interior Seaway.
Etymology Means Fish-Bird, after its fish-like vertebrae
Additional Information They occupied a niche similar to today's seagulls and albatrosses, lived near coastlines and probably ate fish.

Clade Synapsida

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Mammal-like Reptiles

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Genus Dimetrodon (pelycosaurs)

Picture(s) Dimetrodon.jpeg
Physical Description Dimetrodon was a quadrupedal apex predator. They grew up to 3.5 meters long(about 50 caudal vertebrae). They have 2 types of teeth - shearing teeth and canine teeth. They have a sail supported by spines sprouting from the vertebrates. One feature that distinguishes them from dinosaurs is their lack of an antorbital fenestra, which is the whole between the eye and nose socket that appears in dinosaurs. The two holes on the back of its skull, temporal fenestrae, link it to mammals.
Fossil Range Permian to Cisuralian.
Mode of Life or Habitat They were an apex predator.
Adaptations Over Time Their sail had many uses, such as thermoregulation, sexual display, looking larger to predators, and stabilization of the spine.
Distribution Mainly Southwestern US, but also Europe.
Etymology "Dimetrodon" means "2 measures teeth."

Genus Lystrosaurus (therapsids)

Picture(s) Lystrosaurus.jpg
Physical Description About 3 feet long. They don't have any teeth besides the tusk-like upper canines. They had huge forearms - thought to be a powerful burrower.
Fossil Range Late Permian to Early Triassic.
Mode of Life or Habitat Desert-like landscape. They were herbivores, and ate plants and roots.
Adaptations Over Time They survived the Permian-Triassic extinction event.
Distribution Mainly Africa.
Additional Information "Lystrosaurus" means "shovel lizard." For a while, 95% of all land vertebrates were Lystrosaurus. They are good index fossils.

Class Mammalia (Mammals)

Picture(s) Mammalia.jpg

Genus Basilosaurus (prehistoric whale)

Picture(s) Basilosaurus.jpg
Physical Description Basilosaurus was an enormous prehistoric whale amd was one of the largest whales to exist at its time. They had several features in their ears, similar to modern whales, that allowed them to hear directionally underwater. Unlike moder whales, Basilosaurus chewed its food, its bite force was 3,600 pounds per square inch.
Taxonomy Kingdom Animalia, Phylum Chordata, Class Mammalia, Order Artiodactyla, Family Basilosauridae, Genus Basilosaurus
Distribution Mostly on the Gulf Coast of the US, Probably inhabited the Tethys Sea, Wadi El Hitan or "Valley of the Whales", was a site in Egypt where many prehstoric whales were found.
Etymology Means ”king of lizards”
Additional Information State fossil of Alabama. Basilosaurus once suffered from the waste basket taxon effect, where many different cetaceans were assigned to the same genus. Basilosaurus was a heterodont, meaning it had differentiated teeth like mmolars and canines.

Genus Equus (modern horse)

Picture(s) Equus.jpg
Physical Description Quadrupedal mammals that eat mainly grass and other harsh vegetation.They sopprt they weight on one digit and serve a key role in many ecosystems.
Fossil Range 4.5-4 million years ago to present
Taxonomy Kingdom:Animalia Phylum:Chordata Class:Mammalia Order:Perissodactyla Family:Equidae Genus:Equus
Adaptations Over Time High crowned teeth allow them to eat grass. They also have an extremely long digestive tract,
Distribution While they wereprobably endemic to North America they spread to Europe.
Etymology first described by Carl Linnaeus in 1758

Genus Australopithecus (hominin)

This fossil will only be tested at the State and National levels.

Picture(s) Australopithecus.jpg
Physical Description They had large brains and were probably bipedal as they had specialised pelvises. The shared features with modern humans as well as with chimpanzees. They also exhibit sexual dimorphism that is much more prominent than that exhibited by modern humans. They also have longer an dmore curved fingers and toes.
Fossil Range Late Pliocene and Early Pleistocene
Adaptations Over Time They seemed to be adapting to living outside of a forest environment and probably lived in grasslands and savannahs.
Distribution Eastern Africa
Etymology "Southern Ape" from Greek and Latin
Additional Information There are two types of australopithecines, gravile and robust. Associated with the oldowan toolkit.

Genus Homo (hominin)

Picture(s) Homo.jpg
Species H. neanderthalensis
Picture(s) Neanderthalensis.jpg
Common Names Neanderthals
Physical Description Neanderthals were better adapted for colder climates. Some of these adaptions/features include: More muscular, large nose(to retain heat), and shorter limbs.
Taxonomy Animalia, Chordata, Mammalia, Primates, Hominidae, Homo
Distribution Europe and southwestern to central Asia, coastal areas
Etymology Discovered in 1829 and named after the Neander valley where it was found.
Additional Information There is evidence that Neanderthals cared for their sick and buried their dead, their are the earliest known hominid species to do so. Due to their geographic location their diet probably consisted of a lot of meat. They are associated with Mousterian tools.

Species H. erectus

This fossil will only be tested at the State and National levels.

Picture(s) Erectus.jpg
Species H. sapiens
Picture(s) Sapiens.jpg

Genus Mammut (Mastodon)

Picture(s) Mammut.jpg
Physical Description Usually around 2.3 meters tall at the shoulders. Could weigh up to 4.5 tons. They had low-crowned or “bunodont” cheek teeth covered in thick enamel. They had 2 or 3 teeth in each half of the jaw.
Fossil Range Late Miocene-Late Pleistocene
Mode of Life or Habitat They lived in forests. Their social groups consisted of females and young, while the males abandoned the mixed herds once reaching sexual maturity and lived either alone or in male bond groupings. They mainly ate trees and shrubs.
Distribution North and Central America, less common in Africa and Eurasia
Additional Information Their name means "nipple tooth."

Genus Mammuthus (Mammoth)

Picture(s) Hebior Mammoth Clean.png
Physical Description About as large as a modern Asian elephant - 2.5 - 3 meters tall at the shoulder. The teeth consisted of a series of plates surrounding a dentine core. They were held together in a matrix of dental cement.
Fossil Range Early Pliocene-Early Holocene
Mode of Life or Habitat They ate grasses, fruits, shrubs, etc. Baby mammoths ate the dung of the adults.
Distribution North America, Eurasia.
Additional Information The name means “earth” from the Tartar word "mamma."
Species M. primigenius (Wooly Mammoth)
Picture(s) Mprimigenius.jpg
Physical Description About the same size as modern African elephants - shoulder height 2.6 - 3.4 meters. They had 4 functional molars at a time. The tusks in males were usually around 2.5 meters long and weighed 45 kg, while in females they were only about 1.5 meters and weighed around 9 kg. They had an outer layer of long hair which was up to 90 cm long. They also had a denser, shorter inner layer of hair.
Fossil Range Middle Pleistocene to Early Holocene. They became extinct due to climate change or hunting.
Mode of Life or Habitat Grasses, herbaceous plants, flowering plants, shrubs, etc. Adults needed to eat 6 tons of food daily! They lived in matriarchal family groups.
Adaptations Over Time They were well adapted to the cold environment of the last ice age - thick layer of fat, fur, small ears (to minimize frostbite), etc.
Distribution Northern Eurasia and North America.
Additional Information Their name means "first elephant" in Latin. State fossil of Alaska, Nebraska, and Vermont

Genus Megacerops (Brontothere)

Picture(s) Megacerops.jpg
Physical Description Up to 5 meters tall. They had an odd number of toes. The dorsal vertebrae above the shoulders had long spines to support the huge neck muscles needed to carry the heavy skull. They had a pair of blunt horns on their snout.
Fossil Range Late Eocene
Mode of Life or Habitat The shape of its teeth suggests that it preferred food such as soft stems and leaves, rather than tough vegetation. Adults may have used their horns to defend themselves and their calves from predators.
Distribution North America
Additional Information Name means "large-horned face." Closely related to Mesohippus.

Genus Mesohippus (three-toed horse)

Picture(s) Mesohippus.jpg
Physical Description They were about 60 cm tall, 4 feet long, and weighed about 75 pounds. They had three toes.
Fossil Range Middle Eocene to Early Oligocen
Mode of Life or Habitat They were herbivores, although their teeth were unsuited to grazing (this trait was adopted in later, more advanced horses)
Adaptations Over Time Longer legs and longer/larger face than earlier equids. They were faster than earlier horses. They were the first of the three-toed horses.
Distribution North America
Additional Information In Greek, "meso" means "middle" and "hippos" means "horse."

Genus Smilodon (saber-toothed cat)

Picture(s) Smilodon.jpg
Physical Description They weighed up to 400 kg. Their teeth were about 7 inches long and their upper canines were more than 10 inches long. Teeth were fragile, and they had a weaker bite than other big cats. They had a hyoid bone to help them roar. They had shorter but more massive limbs than other felines.
Fossil Range Pleistocene
Mode of Life or Habitat They were carnivores - ate bison, elk, deer, etc. They may have lived in social groups. Canines may have been an attraction during mating.
Distribution North and South America
Additional Information In Greek, "smile" means "chisel" and "odous" means "tooth." There are hundreds of Smilodon fossils in the La Brea Tar Pits.