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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.

Picture(s) Agnatha.jpg
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)

Picture(s) Chondrichthyes.jpg
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.

Picture(s) Xiphactinus.jpg
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

Picture(s) Tiktaalik.jpg
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.
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

Picture(s) Acanthostega.jpg
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

Picture(s) Eryops.jpg
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

Picture(s) Diplocaulus.jpg
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.

Picture(s) Testudines.jpg

Order Icthyosauria (Ichthyosaurs)

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Physical Description Usually around 2-4 meters in length. They could swim at speeds up to 25 mph. They have the largest known eyes of any reptile.
Fossil Range Early Triassic to Late Cretaceous. They were the most abundant in the late Triassic and early Jurassic.
Mode of Life or Habitat Carnivorous, viviparous. Sight was their main sense, and their hearing may have been poor.
Distribution All Mesozoic oceans - Europe and Asia.
Additional Information Their name means "fish lizard."

Order Squamata

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Family Mosasauridae (Mosasaurs)

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Physical Description They were anywhere from 2.5 to 17 meters long. Their jaws were double-hinged and flexible, so they would often gulp down their prey whole. They had an expanded chest region, suggesting that they had 2 lungs.
Fossil Range Late Cretaceous
Mode of Life or Habitat Warm, shallow seas. They were dominant marine predators. They were viviparous.
Distribution Worldwide.
Additional Information They are probably related to snakes due to similarities in their jaws and skulls.

Order Plesiosauria (Plesiosaurs & Pliosaurs)

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Physical Description They were anywhere from 3 to 20 meters long. They had a broad, flat body and a short tail. Their necks had up to 70 vertebrae. Plesiosaurs had long necks, small heads, and were slow, while pliosaurs had shorter necks, large heads, and were apex predators. They had a euryapsid skull.
Fossil Range Late Triassic - Late Cretaceous. Became extinct in the Cretaceous-Paleogene extinction event.
Mode of Life or Habitat Oceanic environment. Plesiosaurs ate fish and cephalopods. Pliosaurs ate fish, cephalopods, sharks, ichthyosaurs, and even plesiosaurs.
Adaptations Over Time They have two main morphs - plesiosaurs and pliosaurs.
Distribution Worldwide
Additional Information Their name comes from the Greek "plesios" meaning "near to" and "sauros" meaning "lizard."

Order Pterosauria (Pterosaurs)

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Clade Dinosauria (Dinosaurs)

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Order Saurischia (lizard-hipped)

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Suborder Theropoda

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Genus Allosaurus
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Genus Coelophysis
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Genus Dilophosaurus
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Genus Spinosaurus

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

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Genus Tyrannosaurus
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Genus Velociraptor
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Suborder Sauropodamorpha

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Genus Brachiosaurus
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Genus Diplodocus
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Genus Patagotitan

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

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Genus Plateosaurus
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Order Ornithischia (bird-hipped)

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Infraorder Anklyosauria

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Genus Ankylosaurus
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Infraorder Ceratopsia

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Genus Triceratops
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Genus Protoceratops

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

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Infraorder Ornithopoda

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Genus Iguanodon
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Genus Parasaurolophus
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Genus Maiasaura
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Infraorder Pachycephalosauria

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Genus Dracorex
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Infraorder Stegosauria

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Genus Stegosaurus
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Class Aves (Birds)

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Genus Archaeopteryx

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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.
Fossil Range Late Jurassic
Distribution Europe

Genus Titanis (Terror Bird)

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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
Distribution North America

Genus Icthyornis

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

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Clade Synapsida

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Mammal-like Reptiles

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Genus Dimetrodon (pelycosaurs)

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Physical Description They grew up to 3.5 meters long. They have 2 types of teeth - shearing teeth and canine teeth. They have a sail supported by spines sprouting from the vertebrates.
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.
Additional Information "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)

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Genus Basilosaurus (prehistoric whale)

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Genus Equus (modern horse)

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Genus Australopithecus (hominin)

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

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Genus Homo (hominin)

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Species H. neanderthalensis
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Species H. erectus

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

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Species H. sapiens
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Genus Mammut (Mastodon)

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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)

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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)
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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)

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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)

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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)

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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.