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Xiushanosteus
''Xiushanosteus'' is a genus of placoderm from the Huixingshao Formation of China. It contains one species, ''Xiushanosteus mirabilis''. It is one of the earliest known jawed vertebrates, at roughly 435 million years old. ''Xiushanosteus'' is known from around 20 specimens, most of which are complete. Description ''Xiushanosteus'' is roughly long. Its body is dorsoventrally compressed with small, diamond-shaped scales covering it. Along its midline are scales or scutes with a linear ornament, alongside two dorsal fins of similar size, both bearing spines. The caudal fin is epicercal with a round ventral lobe. The head has long, posterolaterally directed head spines, alongside its dermoskeleton having an unusual structure with features from numerous placoderm clades. Dermoskeleton The margins of the skull roof are similar to acanthothoracids, however the plate pattern is closer to actinolepidoids with only one pair of postorbital and paranuchal plates. The skull ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Placodermi
Placoderms (from Ancient Greek πλάξ 'plax'', ''plakos''' plate' and δέρμα 'derma'''skin') are vertebrate animals of the class Placodermi, an extinct group of prehistoric fish known from Paleozoic fossils during the Silurian and the Devonian periods. While their endoskeletons are mainly cartilaginous, their head and thorax were covered by articulated armoured plates (hence the name), and the rest of the body was scaled or naked depending on the species. Placoderms were among the first jawed fish (their jaws likely evolved from the first pair of gill arches), as well as the first vertebrates to have true teeth. They were also the first fish clade to develop pelvic fins, the second set of paired fins and the homologous precursor to hindlimbs in tetrapods. 380-million-year-old fossils of three other genera, '' Incisoscutum'', '' Materpiscis'' and '' Austroptyctodus'', represent the oldest known examples of live birth. Placoderms are thought to be paraphyletic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Placoderms Of Asia
Placoderms (from Ancient Greek πλάξ [''plax'', ''plakos''] 'Plate (animal anatomy), plate' and δέρμα [''derma''] 'skin') are vertebrate animals of the class (biology), class Placodermi, an extinct group of prehistoric fish known from Paleozoic fossils during the Silurian and the Devonian geological period, periods. While their endoskeletons are mainly cartilaginous, their head and thorax were covered by articulated armour (zoology), armoured plates (hence the name), and the rest of the body was scale (zoology), scaled or naked depending on the species. Placoderms were among the first jawed fish (their fish jaw, jaws likely Evolution, evolved from the first pair of gill arches), as well as the first vertebrates to have true tooth, teeth. They were also the first fish clade to develop pelvic fins, the second set of paired fins and the homology (biology), homologous precursor to hindlimbs in tetrapods. 380-million-year-old fossils of three other genera, ''Incisoscutum'', ''M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Placoderm Genera
Placoderms (from Ancient Greek πλάξ 'plax'', ''plakos''' plate' and δέρμα 'derma'''skin') are vertebrate animals of the class Placodermi, an extinct group of prehistoric fish known from Paleozoic fossils during the Silurian and the Devonian periods. While their endoskeletons are mainly cartilaginous, their head and thorax were covered by articulated armoured plates (hence the name), and the rest of the body was scaled or naked depending on the species. Placoderms were among the first jawed fish (their jaws likely evolved from the first pair of gill arches), as well as the first vertebrates to have true teeth. They were also the first fish clade to develop pelvic fins, the second set of paired fins and the homologous precursor to hindlimbs in tetrapods. 380-million-year-old fossils of three other genera, '' Incisoscutum'', '' Materpiscis'' and '' Austroptyctodus'', represent the oldest known examples of live birth. Placoderms are thought to be paraphyletic, cons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silurian Fish Of Asia
The Silurian ( ) is a geologic period and system spanning 23.5 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the third and shortest period of the Paleozoic Era, and the third of twelve periods of the Phanerozoic Eon. As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by a few million years. The base of the Silurian is set at a series of major Ordovician–Silurian extinction events when up to 60% of marine genera were wiped out. One important event in this period was the initial establishment of terrestrial life in what is known as the Silurian-Devonian Terrestrial Revolution: vascular plants emerged from more primitive land plants, dikaryan fungi started expanding and diversifying along with glomeromycotan fungi, and three groups of arthropods (myriapods, arachnids and hexapods) became full ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunaspis
''Lunaspis'' is an extinct genus of armor-plated petalichthyid placoderm fish that lived in shallow marine environments of the Early Devonian period, from approximately 409.1 to 402.5 million year ago.Fossilworks: Gateway to the Paleobiology database. Retrieved March 6, 2017, from Fossilworks, http://www.fossilworks.org/cgi-bin/bridge.pl?page=paleodb Fossils have been found in Germany, China and Australia. There are three different identified species of within the genus ''Lunaspis'': ''L. broilii, L. heroldi, and L. prumiensis.'' Like many other petalichthyid fish, ''Lunaspis'' are flat and have elongated pectoral spines, shortened thoracic armor, and dorsally oriented eyes. ''Lunaspis'' has been studied mainly by German, Australian, and Chinese palaeontologists because of where it is most commonly encountered. The tails are long and thin and resemble a whip, somewhat like extant skates and rays. Description A typical individual of ''Lunaspis'' was a flattened fish with a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enigmatic Placoderm Taxa
Enigmatic is an adjective meaning "mysterious" or "puzzling". It may also refer to: * ''Enigmatic'' (album), a 1970 album by Czesław Niemen * '' Enigmatic: Calling'', a 2005 album by Norwegian progressive metal band Pagan's Mind * Enigmatic scale, musical scale used by Verdi and others * "The Enigmatic", a song by Joe Satriani on the album '' Not of This Earth'' See also * Enigmatic leaf turtle, a species of Asian leaf turtle * Enigmatic moray eel, a species found in the Pacific and Indian Oceans * ''Glaresis ''Glaresis'' is a genus of beetles, sometimes called "Enigmatic scarab beetles", in its own family, Glaresidae. It is closely related to, and was formerly included in, the family Scarabaeidae. Although its members occur in arid and sandy areas wo ...'', a genus of beetles sometimes called "enigmatic scarab beetles" * Enigma (other) {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xiushan County
Xiushan Tujia and Miao Autonomous County (), or Xiushan County for short, is located in the southeast of Chongqing Municipality, China. It is the municipality's southernmost county-level division. Administrative divisions The county administers 4 subdistricts, 17 towns A town is a type of a human settlement, generally larger than a village but smaller than a city. The criteria for distinguishing a town vary globally, often depending on factors such as population size, economic character, administrative stat ..., and 6 townships. * Zhonghe Subdistrict (中和街道) * Wuyang Subdistrict (乌杨街道) * Pingkai Subdistrict (平凯街道) * Guanzhuang Subdistrict (官庄街道) * Qingxichang Town (清溪场镇) * Aikou Town (隘口镇) * Rongxi Town (溶溪镇) * Longchi Town (龙池镇) * Shidi Town (石堤镇) * Erong Town (峨溶镇) * Hong'an Town (洪安镇) * Yajiang Town (雅江镇) * Shiye Town (石耶镇) * Meijiang Town (梅江镇) * Lanqiao Town (兰桥镇) * Gao ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Romundina
''Romundina'' is a small, heavily armored extinct genus of acanthothoracid placoderms which lived in shallow marine environments in the early Devonian (Lochkovian). The name ''Romundina'' honors Canadian geologist and paleontologist Dr. Rómundur (Raymond) Thorsteinsson of Calgary, Alberta, Canada. ''Romundina'' are believed to have lived on Earth between 400 and 419 million years ago. The closest known relative to ''Romundina'' is the acanthothoracid '' Radotina''. The type and only described species is ''R. stellina''. The first specimen of ''Romundina'' was originally discovered by Swedish paleontologist Tor Ørvig in 1975 on Prince of Wales Island (Nunavut) in a formation that geologically dates back to the Gedinnian. Only one known species of ''Romundina'' has been discovered which was named ''Romundina stellina'' by Ørvig. The species name ''stellina'' refers to stellate (derived from Latin word stella meaning star) tubercles that the Placoderm has ornamenting its dermal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Postorbital Bone
The ''postorbital'' is one of the bones in vertebrate skulls which forms a portion of the dermal skull roof and, sometimes, a ring about the orbit. Generally, it is located behind the postfrontal and posteriorly to the orbital fenestra. In some vertebrates, the postorbital is fused with the postfrontal to create a postorbitofrontal. Birds have a separate postorbital as an embryo An embryo ( ) is the initial stage of development for a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sp ..., but the bone fuses with the frontal before it hatches. References * Roemer, A. S. 1956. ''Osteology of the Reptiles''. University of Chicago Press. 772 pp. Skull bones {{Vertebrate anatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Actinolepidae
Actinolepidae is an extinct family of placoderm fishes which lived during the Early Devonian period. They are considered to be among the most primitive of the arthrodires, and are widely accepted to be phylogenetically basal to the group. Description The bodies of Actinolepids are wide and flat, suggesting that most members of this family were benthic fish. Their jaws were comparatively underdeveloped in comparison to the more robust-jawed arthrodires that would come after them, such as ''Dunkleosteus ''Dunkleosteus'' is an extinct genus of large arthrodira, arthrodire ("jointed-neck") fish that existed during the Late Devonian period, about 382–358 million years ago. It was a pelagic fish inhabiting open waters, and one of the first verteb ...'' and '' Coccosteus'', indicating that it likely subsisted primarily on smaller, softer-bodied animals such as mollusks, or worms instead of larger, tougher prey animals. References External links * Devonian placoderms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acanthothoraci
Acanthothoraci (''spine chests'') is an extinct group of chimaera-like placoderms closely related to the rhenanid placoderms. Superficially, the acanthoracids resembled scaly chimaeras and (relatively) heavily armored ptyctodonts. They were distinguished from chimaeras by their 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 by differences in skull anatomy and by 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 be inferred from the mouthplates of fossil specim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
