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Biceratopsinae
The Biceratopsinae is an extinct subfamily of redlichiid trilobites within the family Biceratopsidae, with species of small to average size. Species belonging to this subfamily lived during the Toyonian stage (Upper ''Olenellus''-zone), 516-513 million years ago, in the former continent of Laurentia, including what are today the South-Western United States and Canada. Etymology The Biceratopsinae are named for the type species '' Biceratops nevadensis''. Habitat The Biceratopsinae were probably marine bottom dweller, like all Olenellina. References Cambrian trilobites Cambrian Series 2 first appearances Cambrian Series 2 extinctions Biceratopsidae Arthropod subfamilies {{Redlichiida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bolbolenellus
''Bolbolenellus'' is an extinct genus of trilobites, fossil marine arthropods, with five species attributed to it currently. It can be easily distinguished from all other trilobites by the combination of the absence of dorsal sutures in the head shield like all Olenellina (which in all other trilobite suborders assist in moulding by splitting open), and a distinctly bulbous frontal lobe (L4) of the raised axial area in the head (or cephalon) called glabella. The species lived at the end of the Lower Cambrian. Etymology ''Bolbolenellus'' is the combination of Greek (, “plant with round swelling on underground stem”), and ''Olenellus'', the rather distantly related genus to which all of the species were previously assigned. This refers to the bulb-like swelling of the frontal lobe of the glabella. The names of the species have the following derivations. * ''B. altifrons'' from the Latin altus (“high”) and from Latin frons (“forehead”), to express the species has a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biceratops
''Biceratops'' is an extinct genus of olenelloid redlichiid trilobites, of average size, with the largest specimen long, not including the huge pleural spines of the 3rd segment of the thorax. It lived during the Toyonian stage (last phase of the Upper ''Olenellus''-zone), in what is today the South-Western United States. ''Biceratops'' can easily be distinguished from other members of Biceratopsidae by the absence of genal spines, in combination with effaced features of the raised axial area of the head shield (or glabella), that is bordering the two horn-like projections that carry the eyes. ''Biceratops nevadensis'' is the only known species in this genus (i.e. the genus is monotypic). Etymology The name of the genus is derived from Latin and means ‘two horned-eyes’. The species epithet refers to the US state where it was collected. Description As with most early trilobites, ''Biceratops'' has an almost flat exoskeleton, that is only thinly calcified. It also shares ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eopeachella
''Eopeachella'' is an extinct genus of trilobites, fossil marine arthropods, with species of probably small size (largest headshield (or cephalon) long), entire, articulate specimens have not yet been found. It lived during the Toyonian stage (Upper ''Olenellus''-zone), in what is today the South-Western United States. ''Eopeachella angustispina'' is the only known species in this genus (i.e. the genus is monotypic). Etymology ''Eopeachella'' is named for its early occurrence compared to and presumed closeness to ''Peachella''. The species epithet ''angustispina'' refers to the slender genal spines compared to those in the species of ''Peachella''. Description Only the cephalon of ''Eopeachella'' is known. It is a small sized biceratopsid trilobite, that exhibits the effaced cephalic features that are typical for that family. ''Eopeachella'' has short, stout genal spines, which are somewhat inflated at base and terminate in pointed tips and inflated lateral cephalic border ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biceratopsidae
Biceratopsidae is an extinct family of redlichiid trilobites, with species of small to average size. Species of belonging to this family lived during the Toyonian stage (''Olenellus''-zone), 522–513 million years ago, in the former continent of Laurentia, including what are today the south-western United States and Canada. It contains the subfamilies Biceratopsinae and Bristoliinae. Habitat The Biceratopsidae were probably marine bottom dweller, like all Olenellina. References Olenelloidea Trilobite families Cambrian trilobites Cambrian first appearances Cambrian Series 2 extinctions {{redlichiida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peachella
''Peachella'' is an extinct genus of trilobites, fossil marine arthropods, with species of average size (about long). It lived during the Toyonian stage (Upper ''Olenellus''-zone), , in what is today the southwestern United States. It can easily be distinguished from other trilobites by its club-likgenal spines Etymology ''Peachella'' is named in honor of Benjamin Neeve Peach, a British geologist. The species epithet ''brevispina'' is derived from Latin and means 'short spine'. ''P. iddingsi'' was named in honor of Joseph P. Iddings, an accomplished American geologist. Origin The earliest occurrence of the ancestral '' Eopeachella angustispina'' predates both ''Peachella'' species, its latest occurrence overlaps with ''P. iddingsi'', which, in turn overlaps with ''P. brevispina''. ''E. angustispina'' has thick, tapered, blunt, genal spines and shallow but clear glabellar furrows. This species therefore bridges the morphological gap between the derived ''Peachella'' species an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olenelloides
''Olenelloides armatus'' is an extinct, small sized (about long) olenelloid redlichiid trilobite arthropod. It lived during the later part of the Botomian stage, which lasted from approximately 524 to 518.5 million years ago. This faunal stage was part of the Cambrian Period. The most conspicuous feature is the hexagonal head shield that carries 6 ray-like spines.. Etymology The genus is named after its originally supposed close relationship with '' Olenellus''. The species epithet , a Latin adjective meaning 'armoured', is a reference to the fierce looking spines of the head shield. Occurrence ''Olenelloides armatus'' lived during the late Lower Cambrian deposits presumably contemporary with the middle ''Olenellus''-zone (''Wanneria'' subzone), that probably represents the late Botomian, approximately between 519 and 516 million years ago. Distribution ''Olenelloides armatus'' has been collected from the Fucoid Beds, Northern slopes of the Meall a'Ghiubhais, County R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emigrantia
''Emigrantia'' is an extinct genus of trilobites, fossil marine arthropods, of small to average size. It lived during the Toyonian stage (last phase of the Upper ''Olenellus''-zone), in what is today the South-Western United States. ''Emigrantia'' can easily be distinguished from other trilobites by the sturdy but not inflated genal spines, that are attached at midlength of the cephalon, in combination with effaced features of the raised axial area of the head shield (or glabella). Etymology The name of the genus is derived from Emigrant Pass, Nopah Range, California, near the collection site of many of the last of the Lower Cambrian Olenellina. Description As with most early trilobites, ''Emigrantia'' has an almost flat exoskeleton, that is only thinly calcified. As part of the Olenellina suborder, ''Emigrantia'' lacks dorsal sutures. Like all other members of the Olenelloidea superfamily, the eye-ridges spring from the back of the frontal lobe (L4) of the central area of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nephrolenellus
''Nephrolenellus'' is an extinct genus of trilobite, fossil marine arthropods, of relatively small size (sagittal length of cephalon rarely exceeds 11 mm). Currently two species are attributed to it. ''Nephrolenellus'' lived at the end of the Lower Cambrian. Species are known from the Great Basin of California, Nevada and Arizona, with one specimen from Canada. Taxonomy ''N. geniculatus'' may have been a direct descendant of ''N. multinodus''. Distribution ''Nephrolenellus multinodus'' occurs in the late Lower Cambrian of California (Toyonian, Pyramid Shale Member, Carrara Formation, Inyo County, 35.8° N, 116.2° W). and of Nevada (Toyonian, Lincoln County; and C-Shale Member, Pioche Formation, Ruin Wash, Chief Range, 37.8° N, 114.6° W). Description As with most early trilobites, ''Nephrolenellus'' has an only thinly calcified exoskeleton. Although most of the body is rather flat, the frontal lobe (L4) of the central area of the cephalon (or glabella The glabel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paranephrolenellus
''Paranephrolenellus'' is an extinct genus of trilobite, fossil marine arthropods. Currently four species are attributed to it. ''Paranephrolenellus'' lived at the end of the Lower Cambrian. Etymology ''Paranephrolenellus'' is named for the close similarity of this genus to ''Nephrolenellus ''Nephrolenellus'' is an extinct genus of trilobite, fossil marine arthropods, of relatively small size (sagittal length of cephalon rarely exceeds 11 mm). Currently two species are attributed to it. ''Nephrolenellus'' lived at the end of th ...''. The names of the species are derived as follows. * ''P. besti'' is named in honor of R.V. Best, for his work on the olenelloids of the Laurentian Cordillera. * ''P. inflatus'' refers to the inflation of the lateral cephalic border and base of the genal spines. * ''P. klondikensis'' is named for Klondike Gap, Chief Range, where the species was first discovered. References Cambrian trilobites of North America Redlichiida genera Bic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trilobite Zone
Trilobites are used as index fossils to subdivide the Cambrian period. Assemblages of trilobites define trilobite zones. The ''Olenellus''-zone has traditionally marked the top of the Lower Cambrian, and is followed by the '' Eokochaspis'' zone. The last two zones of the Middle Cambrian are the '' Bathyuriscus– Elrathina''-zone (contemporaneous with the Burgess Shale) and the subsequent '' Bolaspidella''-zone (starting at the base of the Drumian stage). These are overlain by the lowermost Upper Cambrian ''Cedaria''-zone. Alternative zoning names place the Burgess Shale in the ''Peronopsis bonnerensis''-zone, which is underlain by the ''Oryctocephalus indicus''-zone (e.g. Spence Shale) and overlain (perhaps not directly) by the ''Ptychagnostus punctuosus''-zone. The lower Middle Cambrian '' Glossopleura''-zone (Spence Shale) is above the '' Albertella''-zone. The '' Elvinia''-zone is upper Cambrian. Subdivision of the ''Olenellus''-zone Recently, it has been proposed to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laurentia
Laurentia or the North American Craton is a large continental craton that forms the ancient geological core of North America. Many times in its past, Laurentia has been a separate continent, as it is now in the form of North America, although originally it also included the cratonic areas of Greenland and also the northwestern part of Scotland, known as the Hebridean Terrane. During other times in its past, Laurentia has been part of larger continents and supercontinents and itself consists of many smaller terranes assembled on a network of Early Proterozoic orogenic belts. Small microcontinents and oceanic islands collided with and sutured onto the ever-growing Laurentia, and together formed the stable Precambrian craton seen today. The craton is named after the Laurentian Shield, through the Laurentian Mountains, which received their name from the Saint Lawrence River, named after Lawrence of Rome. Interior platform In eastern and central Canada, much of the stable craton is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalon (arthropod Head)
The cephalon is the head section of an arthropod. It is a tagma, i.e., a specialized grouping of arthropod segments. The word cephalon derives from the Greek κεφαλή (kephalē), meaning "head". Insects In insects, ''head'' is a preferred term. The insect head consists of five segments, including three (the labial, maxillary and mandibular) necessary for food uptake, which are altogether known as the gnathocephalon and house the suboesophageal ganglion of the brain, as well as the antennal segment, and an ocular segment, as well as a non segmented fused section of the head where the archicerebrum is housed known as the acron. See also arthropod head problem. Chelicerates and crustaceans In chelicerates and crustaceans, the cephalothorax is derived from the fusion of the cephalon and the thorax, and is usually covered by a single unsegmented carapace. In relation with the arthropod head problem, phylogeny studies show that members of the Malacostraca class of cru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
