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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 tw ... [...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. The stu ... [...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. The stu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phacopidae
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 e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calymenina
Calymenina is a suborder of the trilobite order 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 thoraci .... References Phacopida Prehistoric animal suborders Arthropod suborders Devonian trilobites Trilobites of Australia {{Phacopida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cheirurina
Cheirurina is a suborder of the trilobite order Phacopida. Known representatives range from the uppermost Cambrian (upper Furongian) to the end of the Middle Devonian (Givetian The Givetian is one of two faunal stages in the Middle Devonian Period. It lasted from million years ago to million years ago. It was preceded by the Eifelian Stage and followed by the Frasnian Stage. It is named after the town of Givet in Fra ...). Cheirurina is made up of a morphologically diverse group of related families. References Phacopida Prehistoric animal suborders Arthropod suborders Cambrian trilobites Ordovician trilobites Silurian trilobites Devonian trilobites Furongian first appearances Givetian extinctions {{phacopida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phacops And Walliserops
''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 (" |
Calymene
''Calymene'' Brongniart, 1822, is a genus of trilobites in the order Phacopida, suborder Calymenina, that are found throughout North America, North Africa, and Europe in primarily Silurian outcrops. ''Calymene'' is closely related to ''Flexicalymene'', and both genera are frequently found enrolled. Calymene trilobites are small, typically 2 cm in length. The cephalon is the widest part of the animal and the thorax usually has 13 segments. The correct genus authorship is Brongniart (1822). A previously published genus description in Desmarest (1816) (often mis-cited as "Calymena" Desmarest, 1817) was suppressed by ICZN Opinion 1433. Etymology ''Calymene'' - meaning ''beautiful crescent'' as a reference to the glabella. Known species and locations *†'' Calymene blumenbachii'', Dudley, England - Type *†''Calymene brevicapitata'', N. and S. Wales *†''Calymene breviceps'', Indiana and Illinois *†'' Calymene celebra'', Illinois, Indiana, and Wisconsin. *†''Calymen ... [...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] |
Cheirurus
''Cheirurus'' (from Greek ''χείρ, cheir'' meaning "hand" and ''ουρά, oura'' meaning "tail") is a genus of phacopid trilobites that lived from the Ordovician to the Devonian. Its remains have been found in Africa, Asia, Australia, Europe, and North America. ''Cheirurus'' is the type genus of Cheiruridae. References * ''Trilobite: Eyewitness to Evolution'' by Richard Fortey External links Trilobites.info in 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 ...
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Calymenidae
Calymenidae is a family of 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 ...s, containing the following genera: *'' Alcymene'' *'' Apocalymene'' *'' Arcticalymene'' *'' Calymene'' *'' Calymenella'' *'' Calymenesum'' *'' Colpocoryphe'' *'' Dekalymene'' *'' Diacalymene'' *'' Flexicalymene'' *'' Gravicalymene'' *'' Limbocalymene'' *'' Linguocalymene'' *'' Liocalymene'' *'' Metacalymene'' *'' Neseuretinus'' *'' Neseuretus'' *'' Nipponocalymene'' *'' Onnicalymene'' *'' Papillicalymene'' *'' Paracalymene'' *'' Platycalymene'' *'' Pradoella'' *'' Protocalymene'' *'' Reacalymene'' *'' Reedocalymene'' *'' Salterocoryphe'' *'' Sarrabesia'' *'' Spathacalymene'' *'' Sthenarocalymene'' *'' Tapinocalymene'' *'' Thelecalymene'' *'' Vietnamia'' References Calymenina Trilobite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dalmanites Limulurus
''Dalmanites'' is a genus of trilobite in the order Phacopida. They lived from the Late Ordovician to Middle Devonian. The trilobites of this genus have slightly convex exoskeletons with an average length of . The cephalon is semicircular or parabolic. The glabella (center portion of the head) is often pear-shaped, and tapers outward toward the front. The glabella also always contains three pairs of obvious glabellar furrows. Also prominent are the large mosaic (schizochroal) eyes. The thorax is composed of eleven segments, with the relatively large pygidium with a slender axis of 11 to 16 rings and 6 or 7 pleural ribs. The pygidium ends in a striking tail spike. Taxonomy Species previously assigned to ''Dalmanites'' Some species formerly included in ''Dalmanites'' have now been reassigned to other genera. * ''D. lapeyrei'' = '' Zeliszkella torrubiae'' * ''D. maecurua'' = ''Amazonaspis maecurua'' * ''D. micheli'' = '' Phacopidina micheli'' * ''D. pleione'' = '' Bellacartw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eldredgeops 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 ''El ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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