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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] |
Ductina Vietnamica 2 Frontal
''Ductina'' is a genus of extinct, small to average sized, eyeless phacopid 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) is 2 to 3 times as wide as it is long in the direction of the axis (or sagittally). The cephalic axis (or 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 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 features of the occipital ring. Eyes and eye ridges ( palpebral lobes) are absent. The natural fracture lines (sutu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 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 (""), a biological defense mechanism that is widespread among smalle ... [...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 tw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Denckmannites
''Denckmannites'' is a trilobite in the order Phacopida, that existed during the upper Silurian in what is now the Czech Republic. It was described by Wedekind in 1914, and the type species is ''Denckmannites volborthi'', which was originally described under the genus ''Phacops'' by Barrande in 1852. It also contains the species ''Denckmannites morator'', and ''Denckmannites primaevus''. The type locality was the Kopanina Formation. P.A. Jell and J.M. Adrain. References External links ''Denckmannites'' at the |
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 Pale ... Silurian trilobites of Europe Phacopidae Extinct animals of Europe Paleozoic life of Quebec {{phacopida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryphops
''Cryphops'' is an extinct genus of trilobite in the family 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 ' .... There are at least three described species in ''Cryphops''. Species These three species belong to the genus ''Cryphops'': * † ''Cryphops cryphoides'' * † ''Cryphops cryptophthalmus'' * † ''Cryphops tripartitus'' References Phacopidae Articles created by Qbugbot {{phacopida-stub ... [...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] |
Babinops
''Babinops'' is an extinct genus of trilobite in the family 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 ' .... References Phacopidae Articles created by Qbugbot {{Phacopida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ananaspis
''Ananaspis'' is a genus of trilobite in the order Phacopida, which existed in what is now the Czech Republic. It was described by Campbell in 1967, and the type species is ''Ananaspis fecundis'', which was originally described as ''Phacops fecundus communis'' by Barrande in 1852. P.A. Jell and J.M. Adrain. References External links ''Ananaspis'' at the Paleobiology Database
The Paleobiology Database is a ...
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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
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Acuticryphops
''Acuticryphops'' is a genus of trilobite that lived during the late Frasnian, particularly between the Lower and Upper Kellwasser horizons. It is known from mid-European Avalonia (Harz Mountains and Rhenish Slate Mountains) and Armorica (Thuringia: Schleiz) and the North Gondwana margin (Coumiac, France and central Morocco). cited in Taxonomy ''Acuticryphops'' was probably ancestral to the species of the genus '' Trimerocephalus'', and mainly differs from its supposed eyeless descendants by retaining small eyes. Evolution ''Acuticryphops acuticeps'' is an example of rapid evolution. Subsequent populations exhibit a declining average and an increasing variation in the number of lenses per eye from about 10 to between 7 and 1. This rapid trend does not occur in other characters of the exoskeleton. This suggests the absence rather than the presence of selective pressure on the number of lenses per eye. This is presumably associated with the eustatic deepening that occurre ... [...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] |
