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Rhenanida
Rhenanida ("Rhine (fish)") is an order of scaly placoderms. Unlike most other placoderms, the rhenanids' armor was made up of a mosaic of unfused scales and tubercles. The patterns and components of this "mosaic" correspond to the plates of armor in other, more advanced placoderms, suggesting that the ancestral placoderm had armor made of unfused components, as well. All rhenanids were flattened, ray-like, bottom-dwelling predators that lived in marine environments. Evolution The rhenanids were once presumed to be the most primitive, or at least the closest to the ancestral placoderm, as their armor was made up of a mosaic of tubercles, as opposed to the solidified plates of "advanced" placoderms, such as antiarchs and arthrodires. Through comparing the skull anatomies of ''Jagorina pandora'' with those of antiarchs, the rhenanids are considered to be the sister group of the antiarchs (together with their respective Acanthothoracid relatives). Presence in the fossil record ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gemuendina
''Gemuendina stuertzi'' (named for Gemünden from where it was discovered) is a placoderm of the order Rhenanida, of the seas of Early Devonian Germany. In life, ''Gemuendina'' resembled a scaly ray with an upturned head, or a large-finned stargazer. ''G. stuertzi'' is often invoked as an example of convergent evolution- with its flat body and huge, wing-like pectoral fins it has a strong, albeit superficial similarity to rays. Unlike rays, however, both ''Gemuendina''`s eye Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and conv ...s and nostrils were placed atop the head, facing upward. Furthermore, ''G. stuertzis upturned mouth would have enabled it to suction prey that swam overhead, rather than swallow sediment or suction prey out of the substrate like modern rays. Unlike most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jagorina Pandora
''Jagorina pandora'' is a rhenanid Rhenanida ("Rhine (fish)") is an order of scaly placoderms. Unlike most other placoderms, the rhenanids' armor was made up of a mosaic of unfused scales and tubercles. The patterns and components of this "mosaic" correspond to the plates of ar ... placoderm of Upper Frasnian Germany. As with other rhenanids, it was a flattened, skate-like fish protected in an armor made up of unfused tubercles, and preyed on other, smaller fish by ambushing them from the sea bottom. Although ''J. pandora'' is known primarily from bone fragments and an intact skull, it is the second most studied rhenanid, after '' Gemuendina stuertzi''. It is from ''Jagorina'' that the details of the skull anatomy of rhenanids are known. Although scientists know of the overall anatomy and bodyplan of rhenanids because of ''G. stuertzi'', very little information has been gleaned from the skulls of ''G. stuertzi'', as all of the specimens of that species have been greatl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jagorina
''Jagorina pandora'' is a rhenanid placoderm of Upper Frasnian Germany. As with other rhenanids, it was a flattened, skate-like fish protected in an armor made up of unfused tubercles, and preyed on other, smaller fish by ambushing them from the sea bottom. Although ''J. pandora'' is known primarily from bone fragments and an intact skull, it is the second most studied rhenanid, after ''Gemuendina stuertzi ''Gemuendina stuertzi'' (named for Gemünden from where it was discovered) is a placoderm of the order Rhenanida, of the seas of Early Devonian Germany. In life, ''Gemuendina'' resembled a scaly ray with an upturned head, or a large-finned star ...''. It is from ''Jagorina'' that the details of the skull anatomy of rhenanids are known. Although scientists know of the overall anatomy and bodyplan of rhenanids because of ''G. stuertzi'', very little information has been gleaned from the skulls of ''G. stuertzi'', as all of the specimens of that species have been greatly f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bolivosteus Chacomensis
''Bolivosteus chacomensis'' is a rhenanid placoderm from the Eifelian of Bolivia, and is the only placoderm known from the “Malvinokaffric” invertebrate faunas. The Malvinokaffric faunas represent a series of cold-water ecosystems near or at the South Pole during the Middle Devonian, and apparently lacked the presence of ammonoids, bryozoa Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic invertebrate animals, nearly all living in sedentary colonies. Typically about long, they have a special feeding structure called a ..., or colonial corals. ''B. chacomensis'' is known from skull fragments and scales. References Rhenanida Placoderm genera Placoderms of South America Devonian Bolivia Fossils of Bolivia Fossil taxa described in 1986 {{placoderm-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asterosteus
''Asterosteus'' is genus of rhenanid Rhenanida ("Rhine (fish)") is an order of scaly placoderms. Unlike most other placoderms, the rhenanids' armor was made up of a mosaic of unfused scales and tubercles. The patterns and components of this "mosaic" correspond to the plates of ar ... placoderm from the Eifelian. The type species, ''A. stenocephalus'', is known from an incomplete skull from Middle Devonian strata of Ohio. What may be a second species ("''Asterosteus sp'' Schmidtt 1963") is described from fragments decorated with star-shaped tubercules from the Eifelian-aged Gebze beds of Turkey. References Rhenanida Placoderms of North America Placoderms of Asia Placoderm genera Paleontology in Ohio Eifelian life {{placoderm-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nefudina
''Nefudina qalibahensis'' is a rhenanid Rhenanida ("Rhine (fish)") is an order of scaly placoderms. Unlike most other placoderms, the rhenanids' armor was made up of a mosaic of unfused scales and tubercles. The patterns and components of this "mosaic" correspond to the plates of ar ... placoderm from the early Emsiane during the Early Devonian Epoch of Northeastern Saudi Arabia. It is known from skull fragments and scales.it died out during the end of the emsiane. References https://www.mindat.org/taxon-4842435.html Rhenanida Placoderms of Asia Vertebrates of the Arabian Peninsula Placoderm genera {{placoderm-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bolivosteus
''Bolivosteus chacomensis'' is a rhenanid placoderm from the Eifelian of Bolivia, and is the only placoderm known from the “Malvinokaffric” invertebrate faunas. The Malvinokaffric faunas represent a series of cold-water ecosystems near or at the South Pole during the Middle Devonian, and apparently lacked the presence of ammonoids, bryozoa Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic invertebrate animals, nearly all living in sedentary colonies. Typically about long, they have a special feeding structure called a ..., or colonial corals. ''B. chacomensis'' is known from skull fragments and scales. References Rhenanida Placoderm genera Placoderms of South America Devonian Bolivia Fossils of Bolivia Fossil taxa described in 1986 {{placoderm-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nefudina Qalibahensis
''Nefudina qalibahensis'' is a rhenanid Rhenanida ("Rhine (fish)") is an order of scaly placoderms. Unlike most other placoderms, the rhenanids' armor was made up of a mosaic of unfused scales and tubercles. The patterns and components of this "mosaic" correspond to the plates of ar ... placoderm from the early Emsiane during the Early Devonian Epoch of Northeastern Saudi Arabia. It is known from skull fragments and scales.it died out during the end of the emsiane. References https://www.mindat.org/taxon-4842435.html Rhenanida Placoderms of Asia Vertebrates of the Arabian Peninsula Placoderm genera {{placoderm-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Batoidea
Batoidea is a superorder of cartilaginous fishes, commonly known as rays. They and their close relatives, the sharks, comprise the subclass Elasmobranchii. Rays are the largest group of cartilaginous fishes, with well over 600 species in 26 families. Rays are distinguished by their flattened bodies, enlarged pectoral fins that are fused to the head, and gill slits that are placed on their ventral surfaces. Anatomy Batoids are flat-bodied, and, like sharks, are cartilaginous fish, meaning they have a boneless skeleton made of a tough, elastic cartilage. Most batoids have five ventral slot-like body openings called gill slits that lead from the gills, but the Hexatrygonidae have six. Batoid gill slits lie under the pectoral fins on the underside, whereas a shark's are on the sides of the head. Most batoids have a flat, disk-like body, with the exception of the guitarfishes and sawfishes, while most sharks have a spindle-shaped body. Many species of batoid have developed th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emsian
The Emsian is one of three faunal stages in the Early Devonian Epoch. It lasted from 407.6 ± 2.6 million years ago to 393.3 ± 1.2 million years ago. It was preceded by the Pragian Stage and followed by the Eifelian Stage. It is named after the Ems river in Germany. The GSSP is located in the Zinzil'ban Gorge in the Kitab State Geological Reserve of Uzbekistan, above the contact with the Madmon Formation. In North America the Emsian Stage is represented by Sawkill or Sawkillian time. Biological events During this period, earliest known agoniatitid ammonoid fossils began appearing within this stage after first appearing in previous stage and began to evolutionarily radiate within this stage, in which a new ammonoid order Goniatitida rises in the end of Zlichovian stage (Siberian representation; corresponds to early Eifelian and after the end of Early Devonian, before 391.9 mya Mya may refer to: Brands and product names * Mya (program), an intelligent personal as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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