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![[OPEN] Adopt auction - Sea Serpent](https://images-wixmp-ed30a86b8c4ca887773594c2.wixmp.com/f/75cc1e55-8ae4-406d-9fa4-05a25342ee69/djqsrtl-abffa67d-9e7f-45d2-8ea1-061a58d3bb00.jpg/v1/crop/w_92,h_92,x_20,y_0,scl_0.010819710690345,q_70,strp/_open__adopt_auction___sea_serpent_by_hik_ignite_djqsrtl-92s.jpg?token=eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.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.6V5ccWx0H6q9CyX6B7HTOxGKXmy7cW4AzPzj_7UFRns)
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The Devonian period, lasting from about 420 to 360 million years ago between the Silurian and the Carboniferous, was the time when life on Earth truly became established on dry land. Most animals still lived in water, with many arthropods, mollusks, and other invertebrates from the Silurian still very common, as well as fish. Many different classes of fish filled the seas, rivers, lakes and coastal swamps, their presence was so profound that the Devonian is often called the Age of Fish. Primitive jawless fish still existed but were not as diverse as before as jawed fish evolved into larger forms. Sharks became common for the first time, and true ray-finned(Actinopterygii) fish appeared. The dominant class of fish were the now extinct placoderms, a very diverse group characterized by armoured plates covering the heads and upper-bodies of most species. They ranged from benthic-filter feeders to pelagic predators living in both marine and freshwater environments. Most were modest in size while some grew enormous; the great-white sized Dunkleosteus was the largest creature on the planet at the time and the undisputed apex predator of the Devonian. It and many of its relatives had teeth-like structures made of protrusions of the jaw-bones that sliced prey in half like scissors, while some had true teeth. The earliest evidence of vertebrate viviparity(giving birth to live-young) comes from fossils of placoderms.
Lobe-finned(Sarcopterygii) fish were prominent as well, especially in brackish and freshwater habitats near coasts. These environments were choked with aquatic plants, and the water was relatively low in oxygen. Lobe-finned fish were able to make use of these habitats due to a variety of adaptations; their strong fins made maneuvering through shallow, weed-choked water easier, and many had lungs as well as gills so they could breath air when oxygen was short underwater. During the late Devonian these adaptations allowed some lobe-finned fish to start shifting from a totally aquatic life to a semi-terrestrial life. Life on land had finally begun to take shape, with the first plants evolving into large trees and shrubs forming Earth's first forests. With no large herbivores in existence these forests grew unabated, their spores spread by water and the first seeds spread by the wind. These forests filled the atmosphere with free oxygen, one of the many things that may have enticed some of these fish out of the oxygen-poor waters. Insects and other terrestrial invertebrates were becoming more common as well. These would have been easy prey for the fish, who may have started hunting on land by snatching prey from the waters edge like modern crocodiles. The fact that there was no competition for this new prey on land would have enticed these fish even more. The new world of dry land seemed like a perfect home; plenty of food, shelter and oxygen, protection from the sun's rays via the ozone layer, and no competition from other fish groups. As time went on to the end of the Devonian many lobe-finned fish developed stronger adaptations in order to exploit the dry land; the bones and muscles in their fins grew larger and stronger until they became limbs, their jaws and necks became more flexible so they could take in gulps of air and look around for food above water, and their rib-cages became wider and stronger so they could support their lungs on land. By the end of the period 360 mya these fish had given rise to creatures with legs and lungs strong and developed enough to move and hunt on land; the very first tetrapods and the ancestors to all four-legged land animals today from amphibians and reptiles to dinosaurs, birds, and mammals. However, like modern frogs and salamanders, these animals had thin skin that needed to be kept wet or else the animal would dry out and die, and their eggs lacked water-proof shells and had to be laid in water. Despite their revolutionary adaptations, the first tetrapods were still tied to the water.
The end of the Devonian was marked by another mass extinction event that occurred about 360 mya. Exact causes of this event are uncertain, possibilities include an asteroid impact, changes in Earth's magnetic field, or changes in the atmosphere due to the expansion of the first forests. Whatever the reason, an estimated 50% of animal genera at the time died out, including all but one family of trilobites, many other invertebrate groups, many species of fish and all the armoured placoderms.
†Coccosteus cuspidatus: Coccosteus is a 16 inch long arthrodire placoderm that lived mostly in freshwater. It resembled its much larger and more famous cousin Dunkleosteus, with a head covered in plates of armour and jaws lined with sharp blade-like structures. These blades were kept sharp as the upper and lower jaws closed and opened, grind the blades together.
†Cladoselache fyleri: Cladoselache was the first species of shark to become very abundant in the Devonian seas. Growing up to six feet long it as a modest sized hunter, and itself a likely prey item to giant placoderms like Dunkleosteus. It had a short, rounded snout with strong jaw-closing muscles and grasping teeth. Its sleek, scaleless body and powerful caudal fin made it very agile to help it chase prey and evade predators.
†Pteraspis rostrata: jawless fish started to dwindle at this time, but many with strange armouring still thrived such as Pteraspis. This 8 inch fish had a head covered in plates with a backward-pointing spike on the top and a horn-like rostrum. The scaled body and a row of spikes on the top and a strong tail-fin. The streamlined shape of the body and armour indicate Pteraspis was a capable swimmer.
†Bothriolepis canadensis: the genus Bothriolepis is one of, if not the most successful of all placoderms, with over 100 species found on all continents spanning over 27 million years. Bothriolepis lived in both marine and freshwater habitats. The largest species, B. maxima, grew 39 inches long. The head, thorax and pectoral fins were covered in armour, protecting it from most predators but making it slow. This coupled with the sub-terminal mouth indicates Bothriolepis were benthic-dwelling bottom feeders, eating algae and detritus off the sediment. Some scientists believe these fish possessed lung-like organs and could crawl out of water, though they were not related to the fish that gave rise to tetrapods.
†Eusthenopteron foordi: Eusthenopteron was a six foot long lobe-finned fish that dwelled in swampy coastal waters 385 mya. It was one of the first fish to evolve labyrinthodont teeth with infolded enamel. The bones in its fins were remarkably similar to tetrapod limb bones with a distinct humerus, ulna and radius in the pectoral fin and femur, tibia and fibula in the pelvic fin. Fossils of Eusthenopteron show the earliest evidence of bone-marrow.
†Acanthostega gunnari: this fish-like animal lived 265 mya and represents a stage in tetrapod evolution after Eusthenopteron. The bones and muscles of its fins are much more developed, resembling limbs complete with digits(up to eight) connected by webbing. Despite this it would not have been able to walk; it lacked wrists, it could not bend its foot forward at the elbow, and its ribs were too short to support its lungs out of water. However, its pelvic structure is adapted to withstand the force of gravity out of water, and its jaws and neck would have allowed it to gulp air above the surface. It likely used its limbs and feet to paddle push through marshes thick with plants.
†Materpiscis attenboroughi: this species of placoderm found in Australia is remarkable in that it is the earliest vertebrate known to reproduce with viviparity; giving birth to live young. The fossil was found with an unborn embryo inside the adult with a mineralised umbilical-cord. With a face covered in armor and jaws lined with crushing plates, this foot-long fish likely fed on hard prey-items such as clams or corals.
†Cheirolepis trailli: this fish is one of the earliest ray-finned fish and possessed well-developed fins giving it speed and stability. Its large eyes suggest it hunted at night, and its jaws could open wide enough to swallow prey two-thirds its size.
†Hynerpeton basetti: found in Pennsylvania dating to about 360 mya, Hynerpeton was one of the first tetrapods that could truly walk on land with fully developed limbs. Growing up to six feet long it was much larger than any living amphibian. Like living amphibians Hynerpeton would still have to live near water, likely in lakes or swamps where it hunted for fish, due to its thin skin and soft jelly-like eggs.
Lobe-finned(Sarcopterygii) fish were prominent as well, especially in brackish and freshwater habitats near coasts. These environments were choked with aquatic plants, and the water was relatively low in oxygen. Lobe-finned fish were able to make use of these habitats due to a variety of adaptations; their strong fins made maneuvering through shallow, weed-choked water easier, and many had lungs as well as gills so they could breath air when oxygen was short underwater. During the late Devonian these adaptations allowed some lobe-finned fish to start shifting from a totally aquatic life to a semi-terrestrial life. Life on land had finally begun to take shape, with the first plants evolving into large trees and shrubs forming Earth's first forests. With no large herbivores in existence these forests grew unabated, their spores spread by water and the first seeds spread by the wind. These forests filled the atmosphere with free oxygen, one of the many things that may have enticed some of these fish out of the oxygen-poor waters. Insects and other terrestrial invertebrates were becoming more common as well. These would have been easy prey for the fish, who may have started hunting on land by snatching prey from the waters edge like modern crocodiles. The fact that there was no competition for this new prey on land would have enticed these fish even more. The new world of dry land seemed like a perfect home; plenty of food, shelter and oxygen, protection from the sun's rays via the ozone layer, and no competition from other fish groups. As time went on to the end of the Devonian many lobe-finned fish developed stronger adaptations in order to exploit the dry land; the bones and muscles in their fins grew larger and stronger until they became limbs, their jaws and necks became more flexible so they could take in gulps of air and look around for food above water, and their rib-cages became wider and stronger so they could support their lungs on land. By the end of the period 360 mya these fish had given rise to creatures with legs and lungs strong and developed enough to move and hunt on land; the very first tetrapods and the ancestors to all four-legged land animals today from amphibians and reptiles to dinosaurs, birds, and mammals. However, like modern frogs and salamanders, these animals had thin skin that needed to be kept wet or else the animal would dry out and die, and their eggs lacked water-proof shells and had to be laid in water. Despite their revolutionary adaptations, the first tetrapods were still tied to the water.
The end of the Devonian was marked by another mass extinction event that occurred about 360 mya. Exact causes of this event are uncertain, possibilities include an asteroid impact, changes in Earth's magnetic field, or changes in the atmosphere due to the expansion of the first forests. Whatever the reason, an estimated 50% of animal genera at the time died out, including all but one family of trilobites, many other invertebrate groups, many species of fish and all the armoured placoderms.
†Coccosteus cuspidatus: Coccosteus is a 16 inch long arthrodire placoderm that lived mostly in freshwater. It resembled its much larger and more famous cousin Dunkleosteus, with a head covered in plates of armour and jaws lined with sharp blade-like structures. These blades were kept sharp as the upper and lower jaws closed and opened, grind the blades together.
†Cladoselache fyleri: Cladoselache was the first species of shark to become very abundant in the Devonian seas. Growing up to six feet long it as a modest sized hunter, and itself a likely prey item to giant placoderms like Dunkleosteus. It had a short, rounded snout with strong jaw-closing muscles and grasping teeth. Its sleek, scaleless body and powerful caudal fin made it very agile to help it chase prey and evade predators.
†Pteraspis rostrata: jawless fish started to dwindle at this time, but many with strange armouring still thrived such as Pteraspis. This 8 inch fish had a head covered in plates with a backward-pointing spike on the top and a horn-like rostrum. The scaled body and a row of spikes on the top and a strong tail-fin. The streamlined shape of the body and armour indicate Pteraspis was a capable swimmer.
†Bothriolepis canadensis: the genus Bothriolepis is one of, if not the most successful of all placoderms, with over 100 species found on all continents spanning over 27 million years. Bothriolepis lived in both marine and freshwater habitats. The largest species, B. maxima, grew 39 inches long. The head, thorax and pectoral fins were covered in armour, protecting it from most predators but making it slow. This coupled with the sub-terminal mouth indicates Bothriolepis were benthic-dwelling bottom feeders, eating algae and detritus off the sediment. Some scientists believe these fish possessed lung-like organs and could crawl out of water, though they were not related to the fish that gave rise to tetrapods.
†Eusthenopteron foordi: Eusthenopteron was a six foot long lobe-finned fish that dwelled in swampy coastal waters 385 mya. It was one of the first fish to evolve labyrinthodont teeth with infolded enamel. The bones in its fins were remarkably similar to tetrapod limb bones with a distinct humerus, ulna and radius in the pectoral fin and femur, tibia and fibula in the pelvic fin. Fossils of Eusthenopteron show the earliest evidence of bone-marrow.
†Acanthostega gunnari: this fish-like animal lived 265 mya and represents a stage in tetrapod evolution after Eusthenopteron. The bones and muscles of its fins are much more developed, resembling limbs complete with digits(up to eight) connected by webbing. Despite this it would not have been able to walk; it lacked wrists, it could not bend its foot forward at the elbow, and its ribs were too short to support its lungs out of water. However, its pelvic structure is adapted to withstand the force of gravity out of water, and its jaws and neck would have allowed it to gulp air above the surface. It likely used its limbs and feet to paddle push through marshes thick with plants.
†Materpiscis attenboroughi: this species of placoderm found in Australia is remarkable in that it is the earliest vertebrate known to reproduce with viviparity; giving birth to live young. The fossil was found with an unborn embryo inside the adult with a mineralised umbilical-cord. With a face covered in armor and jaws lined with crushing plates, this foot-long fish likely fed on hard prey-items such as clams or corals.
†Cheirolepis trailli: this fish is one of the earliest ray-finned fish and possessed well-developed fins giving it speed and stability. Its large eyes suggest it hunted at night, and its jaws could open wide enough to swallow prey two-thirds its size.
†Hynerpeton basetti: found in Pennsylvania dating to about 360 mya, Hynerpeton was one of the first tetrapods that could truly walk on land with fully developed limbs. Growing up to six feet long it was much larger than any living amphibian. Like living amphibians Hynerpeton would still have to live near water, likely in lakes or swamps where it hunted for fish, due to its thin skin and soft jelly-like eggs.
Image size
3928x3021px 3.67 MB
Make
Apple
Model
iPhone 6s Plus
Shutter Speed
1/15 second
Aperture
F/2.2
Focal Length
4 mm
ISO Speed
25
Date Taken
Jul 9, 2017, 1:05:47 PM
© 2017 - 2025 MickeyRayRex
Comments12
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An inspiring drawing, I was looking for Silurians and found this.