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Ptyctodont
The ptyctodontids ("folded-teeth") are placoderms of the order Ptyctodontida, containing the family Ptyctodontidae. With their big heads, big eyes, reduced armor and long bodies, the ptyctodontids bore a superficial resemblance to modern day chimaeras (Holocephali). Their armor was reduced to a pattern of small plates around the head and neck. Like the extinct and related acanthothoracids, and the living and unrelated holocephalians, most of the ptyctodontids are thought to have lived near the sea bottom and preyed on shellfish. On account of their radically reduced armor, some paleontologists have suggested that the Ptyctodontida were not actually placoderms, but actual holocephalians, some primitive group of elasmobranch fish, or even were the ancestors of the holocephalians, including the chimaeras. Thorough anatomical examinations of whole fossil specimens reveal that the profound similarities between these two groups are actually very superficial. The major differences ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palaeomylus
The ptyctodontids ("folded-teeth") are placoderms of the order Ptyctodontida, containing the family Ptyctodontidae. With their big heads, big eyes, reduced armor and long bodies, the ptyctodontids bore a superficial resemblance to modern day chimaeras (Holocephali). Their armor was reduced to a pattern of small plates around the head and neck. Like the extinct and related acanthothoracids, and the living and unrelated holocephalians, most of the ptyctodontids are thought to have lived near the sea bottom and preyed on shellfish. On account of their radically reduced armor, some paleontologists have suggested that the Ptyctodontida were not actually placoderms, but actual holocephalians, some primitive group of elasmobranch fish, or even were the ancestors of the holocephalians, including the chimaeras. Thorough anatomical examinations of whole fossil specimens reveal that the profound similarities between these two groups are actually very superficial. The major differences ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chelyophorus
The ptyctodontids ("folded-teeth") are placoderms of the order Ptyctodontida, containing the family Ptyctodontidae. With their big heads, big eyes, reduced armor and long bodies, the ptyctodontids bore a superficial resemblance to modern day chimaeras (Holocephali). Their armor was reduced to a pattern of small plates around the head and neck. Like the extinct and related acanthothoracids, and the living and unrelated holocephalians, most of the ptyctodontids are thought to have lived near the sea bottom and preyed on shellfish. On account of their radically reduced armor, some paleontologists have suggested that the Ptyctodontida were not actually placoderms, but actual holocephalians, some primitive group of elasmobranch fish, or even were the ancestors of the holocephalians, including the chimaeras. Thorough anatomical examinations of whole fossil specimens reveal that the profound similarities between these two groups are actually very superficial. The major differences ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Destnoporella
The ptyctodontids ("folded-teeth") are placoderms of the order Ptyctodontida, containing the family Ptyctodontidae. With their big heads, big eyes, reduced armor and long bodies, the ptyctodontids bore a superficial resemblance to modern day chimaeras (Holocephali). Their armor was reduced to a pattern of small plates around the head and neck. Like the extinct and related acanthothoracids, and the living and unrelated holocephalians, most of the ptyctodontids are thought to have lived near the sea bottom and preyed on shellfish. On account of their radically reduced armor, some paleontologists have suggested that the Ptyctodontida were not actually placoderms, but actual holocephalians, some primitive group of elasmobranch fish, or even were the ancestors of the holocephalians, including the chimaeras. Thorough anatomical examinations of whole fossil specimens reveal that the profound similarities between these two groups are actually very superficial. The major differences ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Goniosteus
The ptyctodontids ("folded-teeth") are placoderms of the order Ptyctodontida, containing the family Ptyctodontidae. With their big heads, big eyes, reduced armor and long bodies, the ptyctodontids bore a superficial resemblance to modern day chimaeras (Holocephali). Their armor was reduced to a pattern of small plates around the head and neck. Like the extinct and related acanthothoracids, and the living and unrelated holocephalians, most of the ptyctodontids are thought to have lived near the sea bottom and preyed on shellfish. On account of their radically reduced armor, some paleontologists have suggested that the Ptyctodontida were not actually placoderms, but actual holocephalians, some primitive group of elasmobranch fish, or even were the ancestors of the holocephalians, including the chimaeras. Thorough anatomical examinations of whole fossil specimens reveal that the profound similarities between these two groups are actually very superficial. The major differences ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australoptyctodus
The ptyctodontids ("folded-teeth") are placoderms of the order Ptyctodontida, containing the family Ptyctodontidae. With their big heads, big eyes, reduced armor and long bodies, the ptyctodontids bore a superficial resemblance to modern day chimaeras (Holocephali). Their armor was reduced to a pattern of small plates around the head and neck. Like the extinct and related acanthothoracids, and the living and unrelated holocephalians, most of the ptyctodontids are thought to have lived near the sea bottom and preyed on shellfish. On account of their radically reduced armor, some paleontologists have suggested that the Ptyctodontida were not actually placoderms, but actual holocephalians, some primitive group of elasmobranch fish, or even were the ancestors of the holocephalians, including the chimaeras. Thorough anatomical examinations of whole fossil specimens reveal that the profound similarities between these two groups are actually very superficial. The major differences ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhynchodus
The ptyctodontids ("folded-teeth") are placoderms of the order Ptyctodontida, containing the family Ptyctodontidae. With their big heads, big eyes, reduced armor and long bodies, the ptyctodontids bore a superficial resemblance to modern day chimaeras (Holocephali). Their armor was reduced to a pattern of small plates around the head and neck. Like the extinct and related acanthothoracids, and the living and unrelated holocephalians, most of the ptyctodontids are thought to have lived near the sea bottom and preyed on shellfish. On account of their radically reduced armor, some paleontologists have suggested that the Ptyctodontida were not actually placoderms, but actual holocephalians, some primitive group of elasmobranch fish, or even were the ancestors of the holocephalians, including the chimaeras. Thorough anatomical examinations of whole fossil specimens reveal that the profound similarities between these two groups are actually very superficial. The major differences ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deinodus
''Deinodus'' is a form genus that includes two species: the form found in the Onondaga Formation of western New York, ''Deinodus bennetti'', and the form found in the Columbus and Limestone of central Ohio, ''Deinodus ohioensis''. Both species are limited to the Eifelian age of the middle Devonian Period, which occurred 398-391 million years ago (Martin, 2002). Denison (1978) postulates that the genus could be an arthrodire or ptyctodont, but places it in his "incertae sedis" section. Individual specimens tend to resemble the ptyctodonts from the same units and ptyctodonts from Australia, so ''Deinodus'' is most likely a ptyctodont. Specimens interpreted as lateral spines may show that ''Deinodus'' was a basal ptyctodont, not far removed from the petalichthids (Martin, 2002). ''Deinodus bennetti'' was first described in 1919 (Hussakof and Bryant). Specimens of ''Deinodus'' exhibit a variety of shapes, though most possess the characteristic large tubercles reported by Hussakof ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ctenurella
''Ctenurella'' (from el, κτείς , 'comb' and el, ουρά , 'tail') is an extinct genus of ptyctodont placoderm from the Late Devonian of Germany. The first fossils were found in the Strunde valley in the Paffrather Kalkmulde. Description As with other ptyctodonts, the armor of ''Ctenurella'' was reduced to a few thin plates on the head and shoulder region. It was also relatively small for a placoderm, at just in length. ''Ctenurella'' had two dorsal fins and the rear of the body was relatively long and low. Most ptyctodonts are presumed to have fed on the ocean floor, but the well-developed fins of this genus indicate that it probably also swam in open waters. ''Ctenurella'' had a long, whip-like tail, large eyes, and robust upper and lower jaw tooth plates. Males also had hook-shaped sex organs, known as claspers. Since analogous features are also found in the unrelated living chimaeras, chimaeras and ptyctodonts are thought to be an example of convergent evolution. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Materpiscis
''Materpiscis'' (Latin for ''mother fish'') is a genus of ptyctodontid placoderm from the Late Devonian located at the Gogo Formation of Western Australia. Known from only one specimen, it is unique in having an unborn embryo present inside the mother, with remarkable preservation of a mineralised placental feeding structure (umbilical cord). This makes ''Materpiscis'' the oldest known vertebrate to show viviparity, or giving birth to live young. Discovery and naming The holotype was found in the Kimberley area of northern Western Australia by Lindsay Hatcher during the 2005 expedition to the Gogo led by John Long of Museum Victoria. Fossils from the Gogo Formation are preserved in limestone nodules, so dilute acetic acid is used to dissolve the surrounding limestone and reveal the fossil, often preserved in three dimensions with minimal distortion. The species was named ''Materpiscis attenboroughi'' in honour of David Attenborough who first drew attention to the significa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Campbellodus
''Campbellodus decipiens'' is an extinct ptyctodontid placoderm fish that lived around 380 million years ago (Late Devonian). Its fossil remains have been found preserved in perfect three-dimensional form from the Gogo Formation of Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th .... Originally it was described from large tooth plates and isolated skull roof bones by Miles & Young (1977). Long (1995) restored the complete fish based on new material found at Gogo in the mid 1980s, and described by Long (1997). ''Campbellodus'' has very short spinal plates, and is unusual in having a high dorsal spine formed by three median dorsal plates. The tooth plates are very robust and the upper plate has a high anterior spine. Sources * Long, J.A. 1995. ''The Rise of Fis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acanthothoracids
Acanthothoraci (''spine chests'') is an extinct group of Chimaera, chimaera-like placoderms who were closely related to the rhenanid placoderms. Superficially, the acanthoracids resembled scaly chimaeras, or (relatively) heavily armored ptyctodonts. They were distinguished from chimaeras by the presence of large scales and plates, a pair of large spines that emanate from their chests (thus, the order's name), tooth-like beak plates, and the typical bone-enhanced placoderm eyeball. They were distinguished from other placoderms due to differences in the anatomy of their skulls, and due to patterns on the skull plates and thoracic plates that are unique to this order. Fossil record Fossils of the Acanthothoracids are found in various deposits from the Lower Devonian throughout the world. Fossils of the Palaeacanthaspids are found in Eurasia and Canada, while the Weejasperaspids have only been found in the Taemas Wee Jasper reef, in Southeastern Australia. Ecology From what can b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ptyctodus
''Ptyctodus'' is an extinct armour-plated fish of the late Devonian. ''Ptyctodus'' belongs to the family Ptyctodontidae and is of the class Placodermi. They share a close resemblance to modern day chimaeras (Holocephali). Fossils of this armour-plated fish have been found in locations such as in Russia, the Michigan Basis, and Arizona, United States. Description and paleobiology ''Ptyctodus'' species come in a variety of different sizes, measured data shows three specimens being 94 millimeters, 24 millimeters, 22 millimeters in length, 23 millimeters, 6 millimeters, 4 millimeter in height, and 18 millimeters, 7 millimeters, and 4 millimeters in thickness. Through time, an evolutionary morphological trait is that the species within Ptyctodontidae reduce the dermal armour. The dentition of the ''Ptyctodus'' has dental elements that are very similarly observed in ''chimaeroids''. Its dental plates are compressed into a thin cutting edge behind the symphysis and measure 3 inches ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
