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Peronopsidae
The Peronopsidae (which may also be called peronopsids) comprise the earliest family of the Agnostina suborder. Species of this family occurred on all Supercontinent, paleocontinents. The earliest representatives of this family first occur just before the start of the Middle Cambrian, and the last disappeared just after the start of the Upper Cambrian. Distribution Peronopsidae are Cosmopolitan distribution, cosmopolitan. Temporal distribution Temporal distribution: * ''Archaeagnostus'', Toyonian (Trilobite zone#Subdivision of the Olenellus-zone, ''Nephrolenellus multinodus''-zone) and Amgan, Amgaian (''Trilobite zone, Ovatoryctocara''-zone). * ''Eoagnostus'', Toyonian (''Nephrolenellus multinodus''-zone) and Amgaian (''Ovatoryctocara''-zone). * ''Peronopsis, Peronopsis (Proacadagnostus)'', Amgaian (''Ovatoryctocara''- and lower ''Kounamkites''-zones). * ''Diplorrhina'', Amgaian (''Ovatoryctocara''- and ''Kounamkites''-zones) * ''Peronopsis, Peronopsis (Peronopsis)'', Amgaian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acadagnostus
''Acadagnostus'' is a genus of trilobite from the Middle Cambrian, with 7 species currently recognized. The type species ''A. acadicus'' has the widest distribution known from any peronopsid (with ''Peronopsis, Peronopsis integer'' and ''P. scutalis'') and has been found in North America, Greenland, England, Western Europe, Eastern Europe, Central Asia, the Altai Mountains, the Siberian shield, China, and Australia. Etymology * ''ancisa'' is Latin meaning 'cut round', referring to the shape of the rear pygidial margin. * ''australis'' is Latin for 'southern'. * ''certus'' is Latin meaning 'definite' or 'sure'. * ''syrma'' is Ancient Greek meaning 'robe with a train', indicating the wide pygidial border in the rear. Description Like all Agnostida, ''Acadagnostus'' is diminutive, with the headshield (or Cephalon (arthropod head)#Trilobites, cephalon) and tailshield (or pygidium) of approximately the same size (or Pygidium#Trilobites, isopygous) and outline. Like all Agnostina ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diplorrhina
''Diplorrhina'' Hawle and Corda (1847) is a genus of trilobite belonging to Order Agnostida. It lived during the early Middle Cambrian ( Amgan and Mayan stages) in what are now the Czech Republic and the North Siberian plateau. as in members of the family Peronopsidae The Peronopsidae (which may also be called peronopsids) comprise the earliest family of the Agnostina suborder. Species of this family occurred on all Supercontinent, paleocontinents. The earliest representatives of this family first occur just b ... it lacks a preglabellar furrow. Both cephalon and pygidium lack spines. It is difficult to distinguish ''Diplorrhina'' from many other peronopsids. Taxonomy The ancestor of ''Diplorrhina'' is most likely one of the Siberian species of the genus '' Archaeagnostus''. ''D. recta'' is the most primitive species and it gave rise to ''D. cuneifera'', which was in turn ancestral to ''Diplorrhina triplicata''. Species previously assigned to ''Diplorrhina'' * ''D. norm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Itagnostus
''Itagnostus'' is a genus of trilobite restricted to the Middle Cambrian. Its remains have been found in Asia, Australia, Europe, and North America. Distribution * ''Itagnostus elkedrensis'' occurs in the Middle Cambrian of Australia (''Ptychagnostus praecurrens''-zone, ''Xystridura templetonensis''-zone, and ''Dinesus''-stage, Elkedra; ''Triplagnostus gibbus''-zone, Sandover Beds; both Northern Territory), the Russian Federation (''Kounamkites''-zone, Nekekit River; ''Liostracus allachjunensis''-zone, Lena River). * ''Itagnostus comis'' is found in the Middle Cambrian of Australia (''Triplagnostus gibbus''-zone, Sandover Beds, Northern Territory). * ''Itagnostus gaspensis gaspensis'' is reported from the Middle Cambrian of the United States (Geddes Formation, Nevada; ''Ptychagnostus atavus''-zone, Wheeler Formation, Drum Mountains, Utah), Canada (upper part, Grosses Roches, St. Laurence, Quebec), Russian Federation (''Tomagnostus fissus''-zone, Lena River). * ''Itagnostus ga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peronopsis
''Peronopsis'' (meaning "broach-like" or possibly "boot-like") is a genus of trilobite restricted to the Middle Cambrian. Its remains have been found in Asia, Australia, Europe, and North America. Etymology The subgenus ''Svenax'' is a contraction of Sven Axel, the given names of the paleontologist Tullberg. Taxonomy Position of ''Peronopsis palmadon'' ''Peronopsis palmadon'' is intermediate between Peronopsidae and Condylopygidae, but it is not clear whether ''P. palmadon'' is ancestral to the Condylopigidae, a condylopigid exhibiting regression towards ancestral characters, or an example of parallel evolution. Species previously assigned to ''Peronopsis'' * ''P. acadica'' = '' Acadagnostus acadicus'' * ''P. bifidus'' = '' Pseudoperonopsis bifidus'' * ''P. bonnerensis'' = '' Pentagnostus (Meragostus) bonnerensis'' * ''P. brunfloensis'' = '' Redeagnostus brunfloensis'' * ''P. bulkurensis'' = '' Pentagnostus (Meragostus) bulkurensis'' * ''P. columbensis'' = '' Pseudo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eodiscina
Eodiscina is trilobite suborder. The Eodiscina first developed near the end of the Cambrian, Lower Cambrian period (late Atdabanian) and became extinct at the end of the Middle Cambrian. Species are tiny to small, and have a thorax of two or three segments. Eodiscina includes six Family (biology), families classified under monotypic taxon, one superfamily (biology), superfamily, Eodiscoidea. Taxonomy The Eodiscina are mostly considered the more primitive suborder of the Agnostida, and the Agnostina the more advanced. Some scholars do not consider the Agnostina true trilobites, and consequently rejected the idea that they were related to the Eodiscina. Consequently, these scientists have proposed to elevate the group to Order (biology), ordinal level, which would thus be called Eodiscida Kobayashi, 1939. Origin The oldest known eodiscoid is ''Tsunyidiscus''. The glabella of ''Tsunyidiscus'' is extremely similar to that of ''Dipharus clarki'', and distinct from all other eodis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentagnostus
''Pentagnostus'' is a genus of trilobites restricted to the Middle Cambrian. Its remains have been found in Siberia, Australia, North America, Scandinavia, and Kazakhstan. Taxonomy The probable ancestor of ''Pentagnostus'' is '' Archaeagnostus''. Two subgenera can be distinguished. The nominate subgenus occurred first and developed into the later subgenus ''Pentagnostus (Meragnostus)'' and the family Ptychagnostidae. Species and distribution Subgenus ''Pentagnostus (Pentagnostus)'' * ''P. anabarensis'' Lermontova, 1940 (type) * ''P. ademptus'' (Prokovskaya and Jegorova, 1972) * ''P. brighamensis'' (Resser, 1938) * ''P. shergouldi'' Laurie, 2004 * ''P. veles'' Öpik, 1979 synonym ''P. endemicus''. Subgenus ''Pentagnostus (Meragnostus)'' * ''P. bonnerensis'' (Resser, 1939) (type Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaeagnostus
''Archaeagnostus'' is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It lived from the terminal Toyonian Cambrian Stage 4 is the still unnamed fourth stage of the Cambrian and the upper stage of Cambrian Series 2. It follows Cambrian Stage 3 and lies below the Wuliuan. The lower boundary has not been formally defined by the International Commission ... to early Amgaian. Species belonging to this genus have been found in Eastern North America, the Newfoundland in Canada, the Henson Gletscher Formation in Greenland, the Nekekit and Molodo Rivers in Eastern Siberia, and in Guizhou, China. References Cambrian trilobites of North America Peronopsidae Agnostida genera Extinct animals of North America Cambrian trilobites of Asia Paleozoic life of Quebec Cambrian genus extinctions {{agnostida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eoagnostus
''Eoagnostus'' is an extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ... genus from a well-known class of fossil marine arthropods, the trilobites. It lived during the terminal Lower Cambrian (Toyonian), until the earliest Middle Cambrian (earliest ''Kounamkites''-zone, part of the lower Amgan, Amgaian). Distribution * ''Eoagnostus roddyi'' terminal Lower Cambrian of the United States (''Bonnia''-zone, Kinzers Shale, Lancaster, New York; Pennsylvania; Vermont)Whittington, H. B. et al. Part O, Treatise on Invertebrate Paleontology. Revised, Volume 1 – Trilobita – Introduction, Order Agnostida, Order Redlichiida. 1997 and the early Middle Cambrian of Newfoundland, and Greenland (around the boundary of ''Ovatoryctocara''-zone, Henson Gletscher Formation). * ''Eoagnostus a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tannudiscus
''Tannudiscus'' Pokrovskaya (1959) is a genus of eodiscinid trilobites belonging to the family Weymouthiidae Kobayashi T. (1943), Order Agnostida (Salter 1864). It lived during the late Lower Cambrian, with remains found in Canada (Newfoundland), China (Gansu), The United Kingdom (England), and the Russian Federation (Tuva, Gorno-Altayskaya). TYPE SPECIES: ''T. tannulaicus'' Pokrovskaya, 1959. Taxonomy The Weymouthiid family shows a trend of shortening the occipital ring. In '' Chelediscus'' and ''Tannudiscus'' the occipital ring is entirely obliterated as in the Agnostina suborder. ''Tannudiscus'' has some other characters it shares with the Agnostina, such as a glabella consisting of two lobes and the occipital ring divided into basal glabellar lobes. Both the glabella and pygidial axis are isolated from the border furrow, and the latter is undivided. It is therefore considered likely that the Agnostina descended directly from a species assignable to ''Tannudiscus''. The e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quadragnostus
''Quadragnostus'' is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It lived during the Cambrian Period The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordovici ..., which lasted from approximately 539 to 485 million years ago. References Cambrian trilobites Peronopsidae Agnostida genera {{agnostida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mayan Stage
The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordovician Period 486.85 Ma. Most of the continents lay in the southern hemisphere surrounded by the vast Panthalassa Ocean. The assembly of Gondwana during the Ediacaran and early Cambrian led to the development of new convergent plate boundaries and continental-margin arc magmatism along its margins that helped drive up global temperatures. Laurentia lay across the equator, separated from Gondwana by the opening Iapetus Ocean. The Cambrian marked a profound change in life on Earth; prior to the Period, the majority of living organisms were small, unicellular and poorly preserved. Complex, multicellular organisms gradually became more common during the Ediacaran, but it was not until the Cambrian that fossil diversity seems to rapidly increase ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weymouthiidae
The Weymouthiidae are an extinct family of eodiscinid agnostid trilobites. They lived during the late Lower Cambrian and earliest Middle Cambrian (Botomian to Delamaran) in the so-called ''Olenellus''- and ''Eokochaspis''-zones in the former paleocontinents of Laurentia, Avalonia, Gondwana. The Weymouthiidae are all blind and lack free cheeks. Taxonomy Ancestors The Weymouthiidae have developed from a stock within the Hebediscidae. Descendants The Weymouthiidae are a paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ... family because the Agnostina suborder is nested within it, particularly in the clade that further consists of the genera ''Mallagnostus'', ''Chelediscus'', ''Tannudiscus'' and ''Jinghediscus''. The trend in the Weymouthiidae to reduce the occ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
