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Phacopid
Phacopidae is a family of phacopid trilobites that ranges from the Lower Ordovician to the Upper Devonian, with representatives in all paleocontinents. Description As in all Phacopina, the eyes (if present) consist of very large (0.5 mm in ''Phacops rana''), separately set lenses without a common cornea (so called schizochroal eyes). However, several phacopids have very few lenses, such as the species of the genera ''Cryphops'', ''Denckmannites'', ''Dienstina'', ''Eucryphops'', ''Nephranops'', and ''Plagiolaria'', or lack eyes altogether, like ''Afrops'', ''Dianops'', ''Ductina'', and ''Trimerocephalus''. The natural fracture lines (sutures) of the head run along the top edges of the compound eye. From the back of the eye these cut to the side of the head ( proparian) and not to the back. In front of the eye, the right and left facial sutures connect in front of the inflated glabella and consequently the free cheeks (or librigenae) are yoked as a single piece. In some of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phacopida
Phacopida ("lens-face") is an order of trilobites that lived from the Late Cambrian to the Late Devonian. It is made up of a morphologically diverse assemblage of taxa in three related suborders. Characteristics Phacopida had 8 to 19 thoracic segments and are distinguishable by the expanded glabella, short or absent preglabellar area, and schizochroal (Phacopina) or holochroal (Cheirurina and Calymenina) eyes. Schizochroal eyes are compound eyes with up to around 700 separate lenses. Each lens has an individual cornea which extended into a rather large sclera. The development of schizochroal eyes in phacopid trilobites is an example of post-displacement paedomorphosis. The eyes of immature holochroal Cambrian trilobites were basically miniature schizochroal eyes. In Phacopida, these were retained, via delayed growth of these immature structures (post-displacement), into the adult form. ''Eldredgeops rana'' ( Phacopidae) and '' Dalmanites limulurus'' (Dalmanitidae) are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trilobite
Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period () and they flourished throughout the lower Paleozoic before slipping into a long decline, when, during the Devonian, all trilobite orders except the Proetida died out. The last extant trilobites finally disappeared in the mass extinction at the end of the Permian about 252 million years ago. Trilobites were among the most successful of all early animals, existing in oceans for almost 270 million years, with over 22,000 species having been described. By the time trilobites first appeared in the fossil record, they were already highly diversified and geographically dispersed. Because trilobites had wide diversity and an easily fossilized exoskeleton, they left an extensive fossil record. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Afrops
''Afrops larvifer'' ("Eye of Africa bearing a mask") is a phacopid trilobite which lived in a marine environment during the Pragian stage in what is now southwestern Algeria. The holotype and only known specimen is an incomplete cephalon that was described by G. Alberti in 1983.Available Generic Names for Trilobites P.A. Jell and J.M. Adrain. References External links ''Afrops'' at the Paleobiology Database
The Paleobiology Datab ...
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Phacops Rana Crassituberculata Eye 2
''Phacops'' is a genus of trilobites in the order Phacopida, family Phacopidae, that lived in Europe, northwestern Africa, North and South America and China from the Late Ordovician until the very end of the Devonian, with a broader time range described from the Late Ordovician.''Phacops'' at .org It was a rounded animal, with a globose head and large eyes, and probably fed on . ''Phacops'' is often found rolled up (" |
Ductina Vietnamica 2 Frontal
''Ductina'' is a genus of extinct, small to average sized, eyeless Phacopida, phacopid Trilobita, trilobite, that lived during the Devonian. Description The body of ''Ductina'' is small to average (up to ), 1¼ to 2 times as long as wide, blunted oval. Body without any adornment. The headshield (or Cephalon (arthropod head), cephalon) is 2 to 3 times as wide as it is long in the direction of the axis (or sagittally). The cephalic axis (or Cephalon (arthropod head), glabella) is strongly widening forward with shallow furrows, the front curving downward to end at an approximate straight angle to the plain of the axis. Another shallow furrow (the occipital furrow), with left and right a deep pit (apodemal pit), crosses to the back of the glabella to define a narrow band (or Cephalon (arthropod head)#Trilobites, occipital ring), and just in front left and right a small lobe is defined by shallow furrows and a deep pits. The back of the cephalon is often broken, obscuring the featur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trilobite
Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period () and they flourished throughout the lower Paleozoic before slipping into a long decline, when, during the Devonian, all trilobite orders except the Proetida died out. The last extant trilobites finally disappeared in the mass extinction at the end of the Permian about 252 million years ago. Trilobites were among the most successful of all early animals, existing in oceans for almost 270 million years, with over 22,000 species having been described. By the time trilobites first appeared in the fossil record, they were already highly diversified and geographically dispersed. Because trilobites had wide diversity and an easily fossilized exoskeleton, they left an extensive fossil record. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chotecops
''Chotecops'' is a genus of trilobites from the order Phacopida, suborder Phacopina, family Phacopidae. It was initially erected as a subgenus of ''Phacops'' but some later authors thought it distinctive enough to raise its status. Species assigned to this genus occur between the Emsian and the Famennian. ''Chotecops'' is the most abundant trilobite in the Hunsrück Slate and due to the excellent preservation, often soft tissue such as antennae and legs have been preserved as a thin sheet of pyrite. Description Like in all sighted Phacopina, the eyes of ''Chotecops'' are compounded of very large, separately set lenses without a common cornea (so called schizochroal eyes), and like almost all other Phacopina, the articulate mid-length part of the body (or thorax) in ''Chotecops'' has 11 segments. The central raised area of the cephalon (called glabella) consists from back to front of an occipital ring, but unlike in its close relative ''Phacops'' the preoccipital ring in ''Chote ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phacopina
The Phacopina comprise a suborder of the trilobite order Phacopida. Species belonging to the Phacopina lived from the Lower Ordovician (Tremadocian) through the end of the Upper Devonian (Famennian).Moore, R.C. (ed.). Treatise on Invertebrate Paleontology. Part O – Arthropoda (Trilobitomorpha). 1959 The one unique feature that distinguishes Phacopina from all other trilobites are the very large, separately set lenses without a common cornea of the compound eye. Habitat As far as known, all Phacopina species were marine bottom-dwellers. Origin The Early Ordovician genus '' Gyrometopus'' (superfamily Dalmanitoidea, family Diaphanometopidae) is probably close to the common ancestor of the Phacopina. ''Gyrometopus'' is phacopid in appearance, but a rostral plate is present, unlike in other Phacopina. However, the rostral plate does not divide the cephalic doublure into a left and right section, but instead the rostral suture defines a semicircle in the frontal ¾ of the doublur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phacops Rana
''Eldredgeops rana'' (formerly ''Phacops rana'') is a species of trilobite from the middle Devonian period. Their fossils are found chiefly in the northeastern United States, and southwestern Ontario. Because of its abundance and popularity with collectors, ''Eldredgeops rana'' was designated the Pennsylvania state fossil by the state's General Assembly on December 5, 1988. Description ''Eldredgeops rana'' can be recognized by its large eyes (which remind some observers of a frog's eyes—the specific name ''rana'' is a reference to a common frog), its fairly large size (up to 6 inches long), and its habit of rolling up into a ball like a pill bug ("volvation"). In order to protect themselves from predators, ''Eldredgeops rana'' would roll into a ball with its hard exoskeleton on the outside as protection. Many other trilobites possessed the same ability, but ''Eldredgeops rana'' nearly perfected it. The slightest amount of sediment would trigger their senses, and ''E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acernaspis
''Acernaspis'' is an extinct genus of trilobite that is known from the Silurian. It contains two species, ''A. elliptifrons'', and ''A. salmoensis''. It is sometimes found preserved in burrows of various forms, sometimes in association with multiple moults, suggesting that it used tunnels as refuges whilst in its vulnerable moulting stage. References External links ''Acernaspis''at the Paleobiology Database The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms. History The Paleobiology Database (PBDB) originated in the NCEAS-funded Phanerozoic Marine Paleo ... Silurian trilobites of Europe Phacopidae Extinct animals of Europe Paleozoic life of Quebec {{phacopida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boeckops
''Boeckops'' is a genus of trilobites in the order Phacopida, which existed in what is now the Czech Republic. It was described by Chlupac in 1972, and the type species is ''Boeckops boecki'', which was originally described as ''Phacops boecki'' by Hawle and Corda in 1847. Boeckops is also been discriped from the lower Devonian of Morocco and Algeria. The Genus Boeckops is interpreted as intermediate from between the traditional genus concept of Phacops and Reedops ''Reedops'' is an extinct genus of phacopid trilobite Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance o .... The Genus Boeckops is regarded as problematic or difficult by McKellar et Chatterton 2009.Ryan C McKellar, Brian DE Chatterton (2009) Early and Middle Devonian Phacopidae (Trilobita) of southern Morocco. Palaeontographica Canadiana 28: 1-110. References Externa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adastocephalum
''Adastocephalum'' is a genus of trilobite in the order Phacopida, which existed in what is now New South Wales, Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma .... It was named by Mitchell in 1919, and the type species is ''Adastocephalum teleotypicum''. P.A. Jell and J.M. Adrain. References External links ''Adastocephalum'' at the [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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