Phacopida

	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 two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Trilobite Trilobites (; meaning "three-lobed entities") are extinction, extinct marine arthropods that form the class (biology), class Trilobita. One of the earliest groups of arthropods to appear in the fossil record, trilobites were among the most successful of all early animals, existing in oceans for almost 270million years, with over 22,000 species having been described. Because trilobites had wide diversity and an easily fossilized mineralised exoskeleton made of calcite, they left an extensive fossil record. The study of their fossils has facilitated important contributions to biostratigraphy, paleontology, evolution, evolutionary biology, and plate tectonics. Trilobites are placed within the clade Artiopoda, which includes many organisms that are morphologically similar to trilobites, but are largely unmineralised. The relationship of Artiopoda to other arthropods is uncertain. Trilobites evolved into many ecological niches; some moved over the seabed as predators, scavengers, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Phacopidae Phacopidae is a family (biology), family of Phacopida, phacopid trilobites that ranges from the Lower Ordovician to the Upper Devonian, with representatives in all Supercontinents, 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 Trilobite#Eyes, schizochroal eyes). However, several phacopids have very few lenses, such as the species of the genus, 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 (Trilobite#Dorsal sutures, proparian) and not to the back. In front of the eye, the right and left facial sutures connect in front of the inflated glabel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	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 Fossilworks .org It was a rounded animal, with a globose head and large eyes, and probably fed on detritus . ''Phacops'' is often found rolled up (" volvation "), a b ... [...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 ...). 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]
	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 currently 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Calymene ''Calymene'' 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 (trilobite anatomy), 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. † ... [...More Info...] [...Related Items...] OR:* [Wikipedia] [Google] [Baidu]
picture info	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'' = '' Bellacart ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Calymenidae Calymenidae is a family (biology), family of trilobites, 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 Calymenidae, Calymenina Trilobite families {{Phacopida-stub ... [...More Info...] [...Related Items...] OR:* [Wikipedia] [Google] [Baidu]
picture info	Flexicalymene ''Flexicalymene'' is a genus of trilobites belonging to the order Phacopida, suborder Calymenina and family Calymenidae. ''Flexicalymene'' specimens can be mistaken for ''Calymene'', '' Gravicalymene'', '' Diacalymene'' and a few other Calymenina genera. They are used as an index fossil in the Ordovician. Ohio and North America are particularly known for being rich with ''Flexicalymene'' fossils. Diagnosis "Glabella parabolic to bell-shaped in outline, with three or four lateral lobes and furrows. Lacks buttress(es) from fixed cheek to lateral glabellar lobe(s). Does not have preglabellar field. No distinct crescentic area outside lateral lobe l p. Facial sutures gonatoparian (exceptionally, can be proparian in Flexicalymene). Genal spines absent. Hypostome without discrete protuberance on anterior lobe of median body." (Siveter, 1976, p. 353) Type species * ''Flexicalymene caractaci'' ( Salter, 1865). By original designation and by monotypy, ''Calymene blumenbachii'' var. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Dalmanitidae Dalmanitidae is a family of trilobites in the order Phacopida that lived from the Floian (Ordovician) to the Devonian and includes 33 genera. References Dalmanitidae, Dalmanitoidea Trilobite families Early Ordovician first appearances Devonian extinctions Fossils of Georgia (U.S. state) {{phacopida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]