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Rhenanids
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 Th ... [...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] |
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 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 eyes 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 other placoderm orders, such as the Antiarchs, or the Arthrodires, ''Gemuendina'' and its four other known relatives (or seven, if the three species of the ichthyolith genus '' Ohioaspis'' are confirmed to be rhenanids) had armor made up of a mosaic of un ... [...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] |
Saudi Arabia
Saudi Arabia, officially the Kingdom of Saudi Arabia (KSA), is a country in Western Asia. It covers the bulk of the Arabian Peninsula, and has a land area of about , making it the List of Asian countries by area, fifth-largest country in Asia, the second-largest in the Arab world, and the largest in Western Asia and the Middle East. It is bordered by the Red Sea to the west; Jordan, Iraq, and Kuwait to the north; the Persian Gulf, Qatar and the United Arab Emirates to the east; Oman to the southeast; and Yemen to the south. Bahrain is an island country off the east coast. The Gulf of Aqaba in the northwest separates Saudi Arabia from Egypt. Saudi Arabia is the only country with a coastline along both the Red Sea and the Persian Gulf, and most of its terrain consists of arid desert, lowland, steppe, and mountains. Its capital and List of cities and towns in Saudi Arabia, largest city is Riyadh. The country is home to Mecca and Medina, the two Holiest sites in Islam, holiest citi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ohio
Ohio () is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Of the List of states and territories of the United States, fifty U.S. states, it is the List of U.S. states and territories by area, 34th-largest by area, and with a population of nearly 11.8 million, is the List of U.S. states and territories by population, seventh-most populous and List of U.S. states and territories by population density, tenth-most densely populated. The state's capital and List of cities in Ohio, largest city is Columbus, Ohio, Columbus, with the Columbus metropolitan area, Ohio, Columbus metro area, Cincinnati metropolitan area, Greater Cincinnati, and Greater Cleveland being the List of metropolitan statistical areas, largest metropolitan areas. Ohio is bordered by Lake Erie to the north, Pennsylvania to the east, West Virginia to the southeast, Kentucky to the southwest, Indiana to the west, and Michigan to the northwest. Ohio is historically known as ... [...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] |
Gondwana
Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final stages of break-up, involving the separation of Antarctica from South America (forming the Drake Passage) and Australia, occurred during the Paleogene. Gondwana was not considered a supercontinent by the earliest definition, since the landmasses of Baltica, Laurentia, and Siberia were separated from it. To differentiate it from the Indian region of the same name (see ), it is also commonly called Gondwanaland. Gondwana was formed by the accretion of several cratons. Eventually, Gondwana became the largest piece of continental crust of the Palaeozoic Era, covering an area of about , about one-fifth of the Earth's surface. During the Carboniferous Period, it merged with Laurasia to form a larger supercontinent called Pangaea. Gondwana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. '' Panthera leo'' (lion) and '' Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants of an ancestral taxon are grouped together (i.e. phylogenetic analysis should c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can reproduction, produce Fertility, fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology (biology), morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a binomial nomenclature, two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
