Difference between revisions of "Fossils/Vertebrates"
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===Genus Acanthostega=== | ===Genus Acanthostega=== | ||
{{Fossils | {{Fossils | ||
− | | Desc = | + | | Desc = 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). |
| Picture = [[File:Acanthostega.jpg|250px]] | | Picture = [[File:Acanthostega.jpg|250px]] | ||
− | | Range = Late Devonian | + | | Range = Late Devonian, 365 mya. |
− | | Tax = | + | | Tax = '''Clade:''' Tetrapodomorpha{{break}}'''Clade:''' Eotetrapodiformes{{break}}'''Clade:''' Elpistostegalia{{break}}'''Clade:''' Stegocephalia |
− | | Mode = | + | | Mode = Rivers and shallow, weed-choked swamps. Probably ate fish. May have spent most of its time in shallow water. |
− | | Adapt = In general, they were | + | | Adapt = 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. |
− | | Distr = | + | | Distr = Northern latitudes. |
| Common = | | Common = | ||
− | | Misc = | + | | Etym = From Ancient Greek ᾰ̓́κᾰνθᾰ ákantha (“thorn” or “spine”) + στεγανός steganós (“roof”), combining to form “spiny roof” |
− | | Extern = | + | | Misc = 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. |
+ | | Extern = https://en.wikipedia.org/wiki/Acanthostega. https://www.thoughtco.com/overview-of-acanthostega-1093636. https://en.wikipedia.org/wiki/Lateral_line. | ||
}} | }} | ||
+ | |||
===Genus Eryops=== | ===Genus Eryops=== | ||
{{Fossils | {{Fossils |
Revision as of 03:11, 4 December 2020
- Main article: Fossils
This page is incomplete. |
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." |
External Links | https://en.wikipedia.org/wiki/Notochord. https://en.wikipedia.org/wiki/Agnatha. https://en.wikipedia.org/wiki/Parietal_eye. |
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. |
External Links | https://en.wikipedia.org/wiki/Bothriolepis. https://en.wikipedia.org/wiki/Placodermi. https://onlinelibrary.wiley.com/doi/full/10.1111/pala.12093. |
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. |
External Links | https://en.wikipedia.org/wiki/Bothriolepis. |
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. |
External Links | https://en.wikipedia.org/wiki/Dunkleosteus. |
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." |
External Links | https://en.wikipedia.org/wiki/Chondrichthyes. https://www.ucl.ac.uk/museums-static/obl4he/vertebratediversity/chondrichthyes.html. https://nhpbs.org/wild/chondrichthyes.asp. http://www.comfsm.fm/~brianl/chondrichthyes.html. |
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. |
External Links | https://en.wikipedia.org/wiki/Shark. |
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. |
External Links | http://fossilworks.org/bridge.pl?a=taxonInfo&taxon_no=34621. https://en.wikipedia.org/wiki/Otodus. |
Genus Carcharocles
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. |
External Links | https://en.wikipedia.org/wiki/Megalodon. |
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. |
External Links | https://en.wikipedia.org/wiki/Batoidea. https://en.wiktionary.org/wiki/Batoidea. |
Superclass Osteichthyes (Bony Fish)
Picture(s) | No pictures have been added as of yet. |
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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. |
External Links | https://en.wiktionary.org/wiki/Osteichthyes. https://en.wikipedia.org/wiki/Osteichthyes. https://en.wikipedia.org/wiki/Evolution_of_fish. |
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. |
External Links | https://en.wikipedia.org/wiki/Actinopterygii. https://en.wiktionary.org/wiki/Actinopterygii. |
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. |
External Links | https://en.wikipedia.org/wiki/Knightia. http://fossilworks.org/bridge.pl?a=taxonInfo&taxon_no=35455. |
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. |
External Links | https://en.wikipedia.org/wiki/Xiphactinus. https://www.thoughtco.com/history-of-xiphactinus-1093712. https://blog.everythingdinosaur.co.uk/blog/_archives/2010/08/22/4610992.html. |
Class Sarcopterygii (lobe-finned)
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. |
External Links | https://en.wikipedia.org/wiki/Eusthenopteron. https://www.wired.com/2012/05/a-new-twist-in-the-tetrapod-tale/. http://fossilworks.org/bridge.pl?a=taxonInfo&taxon_no=34918. |
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. |
External Links | https://en.wikipedia.org/wiki/Latimeria. https://en.wikipedia.org/wiki/West_Indian_Ocean_coelacanth. https://en.wikipedia.org/wiki/Indonesian_coelacanth. |
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. |
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." |
External Links | https://en.wikipedia.org/wiki/Tiktaalik. http://fossilworks.org/bridge.pl?a=taxonInfo&taxon_no=77132. |
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. |
External Links | https://en.wikipedia.org/wiki/Amphibian. |
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. |
External Links | https://en.wikipedia.org/wiki/Acanthostega. https://www.thoughtco.com/overview-of-acanthostega-1093636. https://en.wikipedia.org/wiki/Lateral_line. |
Genus Eryops
Genus Diplocaulus
Class Reptilia (Reptiles)
Order Crocodilia (crocodiles)
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Order Testudines (turtles)
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Order Icthyosauria (Ichthyosaurs)
Order Squamata
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Family Mosasauridae (Mosasaurs)
Order Plesiosauria (Plesiosaurs & Pliosaurs)
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
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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
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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
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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
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Clade Synapsida
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Mammal-like Reptiles
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Genus Dimetrodon (pelycosaurs)
Genus Lystrosaurus (therapsids)
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)
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Genus Homo (hominin)
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Species H. neanderthalensis
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Species H. erectus
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Species H. sapiens
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Genus Mammut (Mastodon)
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." |