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Escuminac Formation
The Escuminac Formation is a geologic formation in Quebec. It preserves fossils dating back to the Devonian period. Description Miguasha National Park is located within this formation along the estuary of the Restigouche River on the south coast of the Gaspé Peninsula. The fossil biota from the Park is thus referred to as the Miguasha biota. The main Miguasha exposures were named the 'René Bureau Cliffs' after the geologist and paleontologist. The formation's depositional environment has been variously considered as lacustrine, estuarine, coastal marine or marine, though evidence from the fossil assemblage, stratigraphic and sedimentological setting, and geochemistry of the sedimentary rocks and bones suggests an estuarine interpretation is most fitting. Fossil content Vertebrates Acanthodians Actinopterygians Jawless fish Placoderms Sarcopterygians Invertebrates Arthropods Ctenophores Plants See also * List of fossiliferous stratigraphic units in Quebec Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological Formation
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by Abraham Gottlob Wer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diplacanthiformes
Diplacanthiformes (also known as Diplacanthida, Diplacanthoidei, or Diplacanthini) is an order of acanthodian fishes which lived during the Devonian Period. Subtaxa * ''incertae sedis'' ** Genus '' Bryantonchus'' ** Genus '' Culmacanthus'' ** Genus '' Devononchus'' ** Genus '' Striacanthus'' ** Genus ''Tetanopsyrus'' * Family Diplacanthidae ** Genus ''Diplacanthus ''Diplacanthus'' is an extinct genus of Mid to Late Devonian fish in the class Acanthodii, known as spiny sharks. Classification The genus was named by Louis Agassiz in 1843. It was formerly regarded as belonging to the Climatiformes but r ...'' ** Genus '' Milesacanthus'' ** Genus '' Ptychodictyon'' ** Genus '' Rhadinacanthus'' * Family Gladiobranchidae? ** Genus '' Gladiobranchus'' ** Genus '' Uraniacanthus''? References Acanthodii Prehistoric fish orders Devonian fish Devonian first appearances Devonian extinctions {{Acanthodii-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euphaneropidae
Euphaneropidae is an extinct family of prehistoric jawless fishes in the extinct order Euphanerida. These fishes are characterised by a greatly elongated branchial apparatus which covers most of the length of the body. Fossils are known from the Lower Silurian and Middle Devonian of Scotland, and the Upper Devonian of Canada. In particular, ''Euphanerops'' is unique in that it has two anal fins. Taxonomy Phylogeny is based on Mikko's Phylogeny Archive * Genus †'' Ciderius'' van der Brugghen 2015 ** †'' Ciderius cooperi'' van der Brugghen 2015 * Genus †'' Cornovichthys'' Newman & Trewin, 2001 ** † ''Cornovichthys blaauweni'' Newman & Trewin, 2001 * Genus †'' Euphanerops'' Woodward 1900 Legendrelepis.html" ;"title="'Legendrelepis">'Legendrelepis'' Arsenault & Janvier 1991** †''Euphanerops longaevus'' Woodward 1900 [''Legendrelepis parenti'' Arsenault & Janvier 1991] References * Super-Class Agnatha. T. Jeffery Parker and William A. Haswell, Textbook of Zoology Verte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endeiolepis
''Endeiolepis'' is an extinct jawless fish that lived during the Late Devonian period, similar to that of extant lampreys Lampreys (sometimes inaccurately called lamprey eels) are an ancient extant lineage of jawless fish of the order Petromyzontiformes , placed in the superclass Cyclostomata. The adult lamprey may be characterized by a toothed, funnel-like s ... for its gill pouches, but ''Endeiolepis'' had an unusually large number of gill pouches. ''Endeiolepis'' was also described as being quite similar to '' Euphanerops'', the main difference being a long series of elongated scales forming a ventrolateral protuberance on each side of Endeiolepis’ body. ''Endeiolepis'' had a strongly heterocercal tail. References Discoveries of ''Endeiolepis'' External links Anaspida genera Devonian jawless fish Late Devonian fish Fossils of Canada {{Devonian-jawless-fish-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jawless Fish
Agnatha (, Ancient Greek 'without jaws') is an infraphylum of jawless fish in the phylum Chordata, subphylum Vertebrata, consisting of both present (cyclostomes) and extinct (conodonts and ostracoderms) species. Among recent animals, cyclostomes are sister to all vertebrates with jaws, known as gnathostomes. Recent molecular data, both from rRNA and from mtDNA as well as embryological data, strongly supports the hypothesis that living agnathans, the cyclostomes, are monophyletic. The oldest fossil agnathans appeared in the Cambrian, and two groups still survive today: the lampreys and the hagfish, comprising about 120 species in total. Hagfish are considered members of the subphylum Vertebrata, because they secondarily lost vertebrae; before this event was inferred from molecular and developmental data, the group Craniata was created by Linnaeus (and is still sometimes used as a strictly morphological descriptor) to reference hagfish plus vertebrates. While a few scientist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cheirolepis Canadensis
''Cheirolepis'' (from el, χείρ , 'hand' and el, λεπίς 'scale') is an extinct genus of ray-finned fish that lived in the Devonian period of Europe and North America. It is the only genus yet known within the family Cheirolepidae and the order Cheirolepiformes. It was among the most basal of the Devonian actinopterygians and is considered the first to possess the "standard" dermal cranial bones seen in later actinopterygians. ''Cheirolepis'' was a predatory freshwater and estuarine animal about long. It had a streamlined body with small, triangular ganoid scales similar to those of the Acanthodii. These scales had a basic structure typical of many early osteichthyans, with a superficial of ganoine overlying dentine, and a basal plate of bone. ''Cheirolepis'' had well-developed fins which gave it speed and stability, and was probably an active predator. Based on the size of its eyes, it hunted by sight. ''Cheirolepiss jaws, lined with sharp teeth, could be opened very ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cheirolepis
''Cheirolepis'' (from el, χείρ , 'hand' and el, λεπίς 'scale') is an extinct genus of ray-finned fish that lived in the Devonian period of Europe and North America. It is the only genus yet known within the family Cheirolepidae and the order Cheirolepiformes. It was among the most basal of the Devonian actinopterygians and is considered the first to possess the "standard" dermal cranial bones seen in later actinopterygians. ''Cheirolepis'' was a predatory freshwater and estuarine animal about long. It had a streamlined body with small, triangular ganoid scales similar to those of the Acanthodii. These scales had a basic structure typical of many early osteichthyans, with a superficial of ganoine overlying dentine, and a basal plate of bone. ''Cheirolepis'' had well-developed fins which gave it speed and stability, and was probably an active predator. Based on the size of its eyes, it hunted by sight. ''Cheirolepiss jaws, lined with sharp teeth, could be opened very ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Actinopterygii
Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or horny spines (rays), as opposed to the fleshy, lobed fins that characterize the class Sarcopterygii (lobe-finned fish). These actinopterygian fin rays attach directly to the proximal or basal skeletal elements, the radials, which represent the link or connection between these fins and the internal skeleton (e.g., pelvic and pectoral girdles). By species count, actinopterygians dominate the vertebrates, and they constitute nearly 99% of the over 30,000 species of fish. They are ubiquitous throughout freshwater and marine environments from the deep sea to the highest mountain streams. Extant species can range in size from ''Paedocypris'', at , to the massive ocean sunfish, at , and the long-bodied oarfish, at . The vast majority of Actinopt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ontogenetic
Ontogeny (also ontogenesis) is the origination and development of an organism (both physical and psychological, e.g., moral development), usually from the time of fertilization of the egg to adult. The term can also be used to refer to the study of the entirety of an organism's lifespan. Ontogeny is the developmental history of an organism within its own lifetime, as distinct from phylogeny, which refers to the evolutionary history of a species. Another way to think of ontogeny is that it is the process of an organism going through all of the developmental stages over its lifetime. The developmental history includes all the developmental events that occur during the existence of an organism, beginning with the changes in the egg at the time of fertilization and events from the time of birth or hatching and afterward (i.e., growth, remolding of body shape, development of secondary sexual characteristics, etc.). While developmental (i.e., ontogenetic) processes can influence su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
