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Medlicottioidea
The Medlicottioidea is one of two superfamilies that make up the Prolecanitida, the other being the Prolecanitoidea. The Medlicottioidea are recognized by their discoidal to thinly lenticular, and involute shells with small umbilici; flat, often grooved venters, and variably complex sutures. Medlicottiacean shells are often more ornamented and may sport ventrolateral nodes or ribs. The Medlicottioidea combines two related families, the ancestral Pronoritidae, descended from the Prolecanitidae in the Upper Mississippian and the derived Medlicottiidae which first appeared in the Lower Pennsylvanian. A third family, the Sageceratidae, considered to be derived from the Medlicottiidae, is included in the Ceratitida in more recent classifications. The Medlicottiaceae have become known by the alternative Medlicottiodea, following the recent ruling by the ICZN The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prolecanitoidea
Prolecanitoidea is a taxonomic superfamily of ammonites, fossil cephalopods. This is one of two superfamilies in the Prolecanitida. The other is the Medlicottioidea. The Prolecanitoidea are found in the Upper Devonian to the Middle Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleoz ... and are recognized basically by their generally smooth discoidal to lentincular shells which have a large umbilicus and goniatitic to ceratitic sutures. In this order, suture complexity developed by the addition of lobes from the umbilical area, across the flanks, during the life (ontogeny) of the animal, and phylogenetically with succeeding genera. The Prolecanitoidea combines two related families, the ancestral Prolecanitidae and the derived Daraelitidae. A third family, the Prodromitida ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prolecanitida
Prolecanitida is an order of extinct ammonoidea, ammonoid cephalopods with discoidal to thinly lenticular shells with goniatitic or ceratitic sutures and which retained the simple retrochoanitic siphuncle with backward extending septal necks. As typical for ammonoids the siphuncle is along the ventral margin. Prolecanitids form a relatively small and stable order within the Ammonoidea with 43 named genera and about 1250 species, but with a long-ranging lineage of about 108 m.y. stretching from the Lower Carboniferous to the Triassic. Although not as diverse as their Goniatitida, goniatitid contemporaries, the Prolecanatida provided the stock from which all later Mesozoic ammonoids were derived. Evolution and phylogeny The origin of the Prolecanitida may be found in the Prolobitidae which was originally included in the Anarcestida but recently removed to the Goniatitida. Following their inception, the Prolecanitida divided into two lineages, identified by superfamilies; the earlier ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medlicottiidae
Medlicottiidae is a family of ammonoid cephalopods belonging to the Prolecanitida, known from the Upper Carboniferous ( Pennsylvanian) to the Early Triassic. Characteristics Medlicottidae are characterized by discoidal to thinly lenticular shells and sutures with a narrow ventral lobe and a modified first lateral saddle. Taxonomy Subfamilies The Medlicottiide, established by Karpinsky in 1889, is by prevailing current perspective divided into five subfamilies. These are the Episageceratinae, Medlicottiinae, Propinacoceratinae, Sicanitinae, and Uddenitinae. The Artioceratinae and Miklukhoceratinae, sometimes included as well, are junior synonyms respectively for the Sicanitinae and Propinacoceratinae. Previously the Medlicottiidae were divided in part L of the Treatise, 1957, into just two subfamilies, the Uddenitinae introduced by Miller and Furnish in 1940 and the Medlicottinae revised from Karpinsky 1889. Higher taxa The Medlicottiidae are included in the superfamily M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ceratitida
Ceratitida is an order that contains almost all ammonoid cephalopod genera from the Triassic as well as ancestral forms from the Upper Permian, the exception being the phylloceratids which gave rise to the great diversity of post Triassic ammonites. Ceratitids overwhelmingly produced planospirally coiled discoidal shells that may be evolute with inner whorls exposed or involute with only the outer whorl showing. In a few later forms the shell became subglobular, in others, trochoidal or uncoiled. Sutures are typically ceratitic, with smooth saddles and serrate or digitized lobes. In a few the sutures are goniatitic while in others they are ammonitic. Taxonomy * Ceratitida **Ceratitoidea ** Choristoceratoidea **Clydonitoidea **Danubitoidea **Dinaritoidea ** Lobitoidea ** Meekoceratoidea ** Megaphyllitoidea ** Nathorstitoidea **Noritoidea ** Otoceratoidea ** Pinacoceratoidea **Ptychitoidea ** Sageceratoidea **Tropitoidea ** Xenodiscoidea Only eight superfamilies are sho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Commission On Zoological Nomenclature
The International Commission on Zoological Nomenclature (ICZN) is an organization dedicated to "achieving stability and sense in the scientific naming of animals". Founded in 1895, it currently comprises 26 commissioners from 20 countries. Organization The ICZN is governed by the "Constitution of the ICZN", which is usually published together with the ICZN Code. Members are elected by the Section of Zoological Nomenclature, established by the International Union of Biological Sciences (IUBS). The regular term of service of a member of the Commission is six years. Members can be re-elected up to a total of three full six-year terms in a row. After 18 continuous years of elected service, a break of at least three years is prescribed before the member can stand again for election. Activities Since 2014, the work of the Commission is supported by a small secretariat based at the National University of Singapore, in Singapore. Previously, the secretariat was based in London and fu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Animal Superfamilies
Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared 5000 years ago. It took thousands of years for writing systems to be widely adopted, with writing spreading to almost all cultures by the 19th century. The end of prehistory therefore came at very different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilisation, and ancient Egypt were the first civilizations to develop their own scripts and to keep historical records, with their neighbors following. Most other civilizations reached the end of prehistory during the following Iron Age. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
