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Helochelydridae
The Helochelydridae are an extinct family of stem-turtles known from fossils found in North America and Europe spanning the Early to Late Cretaceous. Description The skull, shell and osteoderms of helochelydrids are covered in small, cylindrical protuberances, which are a distinctive characteristic of the group. They are thought to be terrestrial, based on the presence of limb osteoderms and bone histology. Their skull morphology is dissimilar to that of extant tortoises, suggesting an omnivorous habit similar to that of box turtles. Taxonomy Helochelydridae includes all turtles that closely related to '' Helochelydra'' than '' Sichuanchelys'', '' Meiolania'', or extant turtles. Although referred to as Solemydidae in recent literature on extinct turtles, Helochelydridae has priority over Solemydidae. They are placed as part of the clade Perichelydia. Some recent studies have recovered them as paracryptodires, though other studies have found them to be more basal than parac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naomichelys
''Naomichelys'' is an extinct genus of helochelydrid stem turtle known from the Cretaceous (Aptian-Campanian) of North America. It is the only member of the family known to be native to North America. Distribution ''Naomichelys'' is known numerous remains from western North America, most notably the holotype partial shell from the Cloverly Formation of Montana and a complete skeleton from the Antlers Formation of Texas. Indetermiate remains are known extending up to the Campanian in the United States and Canada. It is the only known North American member of Helochelydridae.W. G. Joyce, J. Sterli, and S. D. Chapman. 2014. The skeletal morphology of the solemydid turtle Naomichelys speciosa from the Early Cretaceous of Texas. Journal of Paleontology 88(6):1257-1287 Location After * Kootenai Formation, Montana, Early Cretaceous (Aptian) * Arundel Formation, Maryland, Aptian * Cloverly Formation, Montana and Wyoming, Aptian * Trinity Group, Texas, Aptian-Albian * Willow Tan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helochelydra
''Helochelydra'' is an extinct genus of extinct stem turtle known from the Early Cretaceous (Barremian) of the Isle of Wight, southern England. Phylogeny ''Helochelydra'' is a member of the stem turtle family Helochelydridae, which is known from Late Jurassic to Late Cretaceous deposits in North America and Europe. Cladistic analysis recovers Helochelydridae outside the clade leading to crown turtles (Testudines).W. G. Joyce, S. D. Chapman, R. T. J. Moody, C. A. Walker (2011) The skull of the solemydid turtle ''Helochelydra nopcsai'' from the Early Cretaceous of the Isle of Wight (UK) and a review of Solemydidae. ''Special Papers in Palaeontology'': 75-97. Taxonomy ''Helochelydra'' was named in 1928 by Franz Baron Nopcsa for a partial shell ( NHMUK R171) from the Early Cretaceous Wessex Formation of the Isle of Wight that Lydekker (1889) had referred to ''Tretosternon punctatum'', a turtle taxon from the Purbeck Group of Dorset, but no species name was provided. Lapparent de Bro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perichelydia
Perichelydia (from Greek ''peri'' "near" and ''chelys'' "turtle") is a clade within Pantestudines (turtles and their extinct relatives) known from the Middle Jurassic to Holocene. Alongside crown group Testudines, it also contains Helochelydridae, which is known from the Cretaceous of Europe and North America, Sichuanchelyidae from the Middle Jurassic to Paleocene of Asia and Europe, Meiolaniformes, which is known from the Cretaceous to Holocene of South America, Australia and Oceania, and '' Spoochelys'', known from the Mid-Cretaceous Griman Creek Formation of Australia. ''Kallokibotion'' from the Late Cretaceous of Europe is also considered part of this group. Several other groups, including the proposed clade Angolachelonia (containing Thalassochelydia and Sandownidae), Paracryptodira, Macrobaenidae, Sinemydidae and Xinjiangchelyidae, which are sometimes considered members of Cryptodira, have also been found outside crown Testudines in several analyses. These groups are usually ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paracryptodira
__NOTOC__ Paracryptodira is an extinct group of reptiles in the clade Testudinata (which contains modern turtles and their extinct relatives), known from the Jurassic to Paleogene of North America and Europe. Initially treated as a suborder sister to Cryptodira,Gaffney (1975) they were then thought to be a very primitive lineage inside the Cryptodira according to the most common use of the latter taxon.Joyce (2007) They are now often regarded as late-diverging stem-turtles, lying outside the clade formed by Cryptodira and Pleurodira. The paracryptodires are said to have phylogenic relationships, noted as primary subclades, within the Baenidae and Pleurosternidae. Within each subclade, lies many biodiverse turtles that are continuously being investigated and added to the fossil record. Paracryptodires are divided into three main groups, Compsemydidae, known from the Late Jurassic to Paleocene of North America and Europe, Pleurosternidae, known from the Late Jurassic to Early Cretac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Escucha Formation
The Escucha Formation is a geological formation in La Rioja and Teruel provinces of northeastern Spain whose strata date back to the late Aptian to middle Albian stages of the Early Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.Weishampel, et al., 2004 The approximately thick formation underlies the Utrillas Formation and overlies Castrillo de la Reina, Benassal & Oliete Formations. The Escucha Formation comprises siltstones, mudstones, sandstones, coal, siltstones and amber, in which several fossil insects were found. The formation was deposited in a variety of continental to paralic (deltaic) environments.Peyrot et al., 2007 Fossil content The Escucha Formation has provided the following fossils, among others: [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wessex Formation
The Wessex Formation is a fossil-rich English geological formation that dates from the Berriasian to Barremian stages (about 145–125 million years ago) of the Early Cretaceous. It forms part of the Wealden Group and underlies the younger Vectis Formation and overlies the Durlston Formation. The dominant lithology of this unit is mudstone with some interbedded sandstones. It is part of the strata of the Wessex Basin, exposed in both the Isle of Purbeck and the Isle of Wight. While the Purbeck sections are largely barren of vertebrate remains, the Isle of Wight sections are well known for producing the richest and most diverse fauna in Early Cretaceous Europe. Nomenclatural History The Wessex Formation has historically alternately been called the "Variegated Marls And Sandstones", a name used by W. J. Arkell in his 1947 map of the Isle of Purbeck as well as the "Wealden Marls" It was given its current formal name by Daley and Stewart in 1979 Stratigraphy and Lithology In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angeac-Charente Bonebed
The Angeac-Charente bonebed is a fossil deposit located near Angeac-Charente in western France. It dates to the Berriasian stage of the Early Cretaceous, and is coeval with the Purbeck Group of Southern England. It has amongst the most diverse assemblages of earliest Cretaceous vertebrates known from Europe. History of discovery Dinosaur bones were first found at the site in 2008. The fossils were exposed during quarrying for overlying Pleistocene aged sand and gravel. After more bones were discovered in 2010, a team was set up composed of people from Musée d’Angoulême, Rennes University and the Muséum national d’Histoire naturelle to excavate the site. Due the promising finds, since 2011 excavations have been conducted at the site annually.Ronan Allain, Romain Vullo, Lee Rozada, Jérémy Anquetin, Renaud Bourgeais, et al.Vertebrate paleobiodiversity of the Early Cretaceous (Berriasian) Angeac-Charente Lagerstätte (southwestern France): implications for continental faunal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maastrichtian
The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval from . The Maastrichtian was preceded by the Campanian and succeeded by the Danian (part of the Paleogene and Paleocene). The Cretaceous–Paleogene extinction event (formerly known as the Cretaceous–Tertiary extinction event) occurred at the end of this age. In this mass extinction, many commonly recognized groups such as non-avian dinosaurs, plesiosaurs and mosasaurs, as well as many other lesser-known groups, died out. The cause of the extinction is most commonly linked to an asteroid about wide colliding with Earth, ending the Cretaceous. Stratigraphic definitions Definition The Maastrichtian was introduced into scientific literature by Belgian geologist André Hubert Dumont in 1849, after studying rock strata of the Chalk Group c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Campanian
The Campanian is the fifth of six ages of the Late Cretaceous Epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campanian spans the time from 83.6 (± 0.2) to 72.1 (± 0.2) million years ago. It is preceded by the Santonian and it is followed by the Maastrichtian. The Campanian was an age when a worldwide sea level rise covered many coastal areas. The morphology of some of these areas has been preserved: it is an unconformity beneath a cover of marine sedimentary rocks. Etymology The Campanian was introduced in scientific literature by Henri Coquand in 1857. It is named after the French village of Champagne in the department of Charente-Maritime. The original type locality was a series of outcrop near the village of Aubeterre-sur-Dronne in the same region. Definition The base of the Campanian Stage is defined as a place in the stratigraphic column wher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solemys
''Solemys'' is an extinct genus of stem turtle known from the Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ... (late Campanian-early Maastrichtian) of southern France and eastern Spain. Taxonomy Two species are known, the type species ''Solemys gaudryi'' (Matheron, 1869) and ''S. vermiculata'' de Lapparent de Broin and Murelaga, 1996. The former was originally assigned to the Cenozoic turtle genus ''Apholidemys'' by Matheron (1869), but de Lapparent de Broin and Murelaga (1996) recognized it as a stem turtle distinct from ''Apholidemys'' and renamed it ''Solemys''.F. d.e. Lapparent de Broin and X. Murelaga. 1996. Une nouvelle faune de chéloniens dans le Crétacé supérieur européen. Comptes Rendus de l’Académie des Sciences de Paris 323:729-735 References ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upper Greensand Formation
The Upper Greensand Formation is a Cretaceous formation of Albian to Cenomanian in age, found within the Wessex Basin and parts of the Weald Basin in southern England. It overlies the Gault Clay and underlies the Chalk Group. It varies in thickness from zero to 75 m. It is predominantly a glauconitic fine-grained sandstone, locally becoming silty. Fragmentary dinosaur remains, such as those assigned to ''Iuticosaurus'', have been recovered from this formation. It has been quarried as a building stone from Roman times, and used in London and the area of its outcrop from Devon to East Sussex. Use Sandstones from the Upper Greensand have been used as building stone since at least Roman times. Reigate Stone was mined from the Upper Greensand in north east Surrey throughout the middle ages and early modern period, forming the most important source of freestone in Medieval London. In Dorset, the Shaftesbury Sandstone was quarried between Shaftesbury and Okeford Fitzpaine and used i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
