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Helveticosauridae
Helveticosauridae is an extinct family of basal marine reptiles known from the Middle Triassic (Anisian-Ladinian boundary) of southern Switzerland and northern Italy. The type species of the family is '' Helveticosaurus zollingeri'', named by Bernhard Peyer in 1955 based on a single nearly complete specimen T 4352 collected at Cava Tre Fontane from the Anisian-Ladinian boundary of Monte San Giorgio, Switzerland. Peyer (1955) considered the species to be a very distinctive member of the order Placodontia, and thus erected Helveticosauridae as well as the superfamily Helveticosauroidea to contain it within Placodontia. Nosotti and Rieppel (2003) described ''Eusaurosphargis'' from the equivalent beds at Cava di Besano of the Besano Formation (Anisian-Ladinian boundary) of Italy. Their phylogenetic analysis recovered it as the sister taxon of ''Helveticosaurus'', and thus it was assigned to Helveticosauridae. Based on the description in the literature available for ''Saurosphar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helveticosaurus
''Helveticosaurus'' is an extinct genus of diapsid marine reptile known from the Middle Triassic (Anisian-Ladinian boundary) of southern Switzerland. It contains a single species, ''Helveticosaurus zollingeri'', known from the nearly complete holotype T 4352 collected at Cava Tre Fontane of Monte San Giorgio, an area well known for its rich record of marine life during the Middle Triassic. Description and paleobiology ''Helveticosaurus'' is known from a nearly complete holotype which includes the premaxilla, maxilla, prefrontal, postfrontal, postorbital, squamosal, dentary and a postcranial skeleton. Several disarticulated elements are also known including teeth, portions of the snout and poscranial elements. ''Helveticosaurus'' is estimated to be about long from snout to tail. It possessed many features that were adaptations to a marine lifestyle in the shallow-sea environment that existed in Europe at the time when much of the continent was part of the Tethys Ocean. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helveticosaurus Zollingeri
''Helveticosaurus'' is an extinct genus of diapsid marine reptile known from the Middle Triassic (Anisian-Ladinian boundary) of southern Switzerland. It contains a single species, ''Helveticosaurus zollingeri'', known from the nearly complete holotype T 4352 collected at Cava Tre Fontane of Monte San Giorgio, an area well known for its rich record of marine life during the Middle Triassic. Description and paleobiology ''Helveticosaurus'' is known from a nearly complete holotype which includes the premaxilla, maxilla, prefrontal, postfrontal, postorbital, squamosal, dentary and a postcranial skeleton. Several disarticulated elements are also known including teeth, portions of the snout and poscranial elements. ''Helveticosaurus'' is estimated to be about long from snout to tail. It possessed many features that were adaptations to a marine lifestyle in the shallow-sea environment that existed in Europe at the time when much of the continent was part of the Tethys Ocean. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Besano Formation
The Besano Formation is a geological formation in the southern Alps of northwestern Italy and southern Switzerland. This formation, a short but fossiliferous succession of dolomite and black shale, is famous for its preservation of Middle Triassic marine life including fish and aquatic reptiles. It is exposed in the vicinity of Monte San Giorgio and is among the formations responsible for the area being designated as a UNESCO World Heritage Site. In Switzerland, it is also known as the Grenzbitumenzone. Geology General geology The Grenzbitumenzone is a relatively thin band of dark dolomite and shale, approximately 5 to 16 meters in total thickness. It extends about 10 km from east to west along the northern edge of Monte San Giorgio. In individual outcrops, the Grenzbitumenzone overlies the lower part of San Salvatore Dolomite, a thick and widespread carbonate-rich formation. The later parts of the San Salvatore Formation, exposed north of Monte San Giorgio, are partiall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eusaurosphargis Dalsassoi
''Eusaurosphargis'' is an extinct genus of a diapsid reptile, known from the Middle Triassic (Anisian and Ladinian age) Besano Formation of northern Italy and Prosanto Formation of south-eastern Switzerland. It contains a single species, ''Eusaurosphargis dalsassoi''. It was a small reptile, measuring long. Discovery The holotype of ''Eusaurosphargis dalsassoi'' (BES SC 390) is a partial skeleton of a single individual found disarticulated but in close association. BES SC 390 was collected from an oil shale at Cava di Besano of the Besano Formation (Grenzbitumenzone). These lagoonal beds are equivalent to those at Monte San Giorgio, dating to the Anisian-Ladinian boundary, probably to the latest Anisian at this location, of the early Middle Triassic, about 243 million years ago. Nicole Klein and Oliver J. Sichelschmidt (2014) described disarticulated remains they referred to ''Eusaurosphargis sp''. These remains were collected from the Dutch Winterswijk Quar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saurosphargidae
Saurosphargidae is an extinct family of marine reptiles known from the early Middle Triassic (Anisian stage) of Europe and China. The type species of the family is '' Saurosphargis volzi'', named by Friedrich von Huene in 1936 based on a single specimen collected from the lower Anisian Lower Muschelkalk of Gogolin, Poland - a section of 12 incomplete back vertebrae with ribs. The generic name of ''Saurosphargis'' is derived from Greek ''sauros'', "lizard", and ''sphargis'', the old genus name for the leatherback turtle, in reference to the dorsal osteoderm "body armor" and broadened ribs forming a closed chest rib basket, traits that are seemingly transitional between turtles and other reptiles. However, due to the only known specimen' destruction during World War II, many authors considered ''Saurosphargis'' to be a ''nomen dubium''. Nevertheless, even based on surviving descriptions alone, many differences were noted even from its closest known relative at the time, '' Eusaur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nomen Dubium
In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium'' it may be impossible to determine whether a specimen belongs to that group or not. This may happen if the original type series (i. e. holotype, isotype, syntype or paratype) is lost or destroyed. The zoological and botanical codes allow for a new type specimen, or neotype, to be chosen in this case. A name may also be considered a ''nomen dubium'' if its name-bearing type is fragmentary or lacking important diagnostic features (this is often the case for species known only as fossils). To preserve stability of names, the ''International Code of Zoological Nomenclature'' allows a new type specimen, or neotype, to be chosen for a ''nomen dubium'' in this case. 75.5. Replacement of unidentifiable name-bearing type by a neotype. When an author considers that the taxonomic identity of a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinosaurosphargis
''Sinosaurosphargis'' is an extinct genus of basal marine saurosphargid reptile known from the Middle Triassic (Anisian age) Guanling Formation of Yunnan and Guizhou Provinces, southwestern China. It contains a single species, ''Sinosaurosphargis yunguiensis''. Discovery ''Saurosphargis'' is known from several individuals, all of which were collected from Member II of the Guanling Formation, dating to the Pelsonian substage of the latest Anisian stage of the early Middle Triassic, about 243 million years ago. The holotype IVPP V 17040 and paratype IVPP V 16076 are housed at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, and represent a nearly complete articulated skeleton and skull, and a partial disarticulated postcranial skeleton including dorsal vertebra, ribs, with osteoderms and gastral rib fragments, respectively. ZMNH M 8797, an incomplete postcranial skeleton showing a very well preserved right forelimb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, the equivalent Latin term ''cladus'' (plural ''cladi'') is often used in taxonomical literature. The common ancestor may be an individual, a population, or a species (extinct or extant). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed monophyletic (Greek: "one clan") groups. Over the last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming taxa that are not clades; that is, taxa that are not monophyletic. Some of the relationships between organisms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holotype
A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several examples, but explicitly designated as the holotype. Under the International Code of Zoological Nomenclature (ICZN), a holotype is one of several kinds of name-bearing types. In the International Code of Nomenclature for algae, fungi, and plants (ICN) and ICZN, the definitions of types are similar in intent but not identical in terminology or underlying concept. For example, the holotype for the butterfly '' Plebejus idas longinus'' is a preserved specimen of that subspecies, held by the Museum of Comparative Zoology at Harvard University. In botany, an isotype is a duplicate of the holotype, where holotype and isotypes are often pieces from the same individual plant or samples from the same gathering. A holotype is not necessarily "typ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saurosphargis
''Saurosphargis'' is an extinct genus of a basal marine reptile, saurosphargid, known from the Middle Triassic (Anisian age) of southwestern Poland and eastern Netherlands. It contains a single species, ''Saurosphargis volzi''. Discovery ''Saurosphargis'' is known solely from the unnumbered holotype that was housed at the Breslaw Museum, a partial postcranial skeleton that included a section of 12 incomplete back vertebrae with ribs. The specimen collected at Gogolin, Gorny Slask of Upper Silesia, Poland, from the Chorzower Schichten horizon of the Lower Muschelkalk, dating to the early Anisian stage of the early Middle Triassic, about 246 million years ago. Rieppel (1995) described an isolated vertebra MGU Wr. 3873s housed at Institute of Geological Sciences, University of Wroclaw, that is possibly referable to ''Saurosphargis'', collected from the same general location. The holotype was destroyed during World War II, and as a result many authors considered ''S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sister Taxon
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and taxon B are sister groups to each other. Taxa A and B, together with any other extant or extinct descendants of their most recent common ancestor (MRCA), form a monophyletic group, the clade AB. Clade AB and taxon C are also sister groups. Taxa A, B, and C, together with all other descendants of their MRCA form the clade ABC. The whole clade ABC is itself a subtree of a larger tree which offers yet more sister group relationships, both among the leaves and among larger, more deeply rooted clades. The tree structure shown connects through its root to the rest of the universal tree of life. In cladistic standards, taxa A, B, and C may represent specimens, species, genera, or any other taxonomic units. If A and B are at the same taxonomi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogenetic Analysis
In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups of organisms. These relationships are determined by Computational phylogenetics, phylogenetic inference methods that focus on observed heritable traits, such as DNA sequences, protein amino acid sequences, or morphology. The result of such an analysis is a phylogenetic tree—a diagram containing a hypothesis of relationships that reflects the evolutionary history of a group of organisms. The tips of a phylogenetic tree can be living taxa or fossils, and represent the "end" or the present time in an evolutionary lineage. A phylogenetic diagram can be rooted or unrooted. A rooted tree diagram indicates the hypothetical common ancestor of the tree. An unrooted tree diagram (a network) makes no assumption about the ancestral line, and does n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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