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Angeac-Charente bonebed

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Angeac-Charente bonebed
Stratigraphic range: Berriasian
The Angeac-Charente bonebed in 2011.
TypeBed
UnderliesUnconformity with Pleistocene deposits
Thickness2 metres
Lithology
PrimaryClay
Location
ExtentAquitaine Basin

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

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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.[1]

Geology and Paleoenvironment

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The site was previously considered Hauterivian-Barremian in age,[2] but is now considered likely middle-late Berriasian in age. The paleoenvironment is considered to have been a freshwater floodplain, dominated by cheirolepidacean conifers, with a tropical or subtropical climate. The lithology of the site is predominantly clay.[1]

Paleobiota

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Fish

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Fish of the Angeac bed
Genus Species Location Stratigraphic position Abundance Notes Images
Parvodus P. celsucuspus Teeth Hybodont shark
Cf. Micropycnodon Indeterminate Teeth Mesturid pycnodontiform fish
Pycnodontidae Indeterminate Teeth
Ginglymodi Indeterminate Teeth and ganoid scales
Amiiformes Indeterminate "teeth, jaw remains and vertebrae"
Ionoscopiformes Indeterminate Teeth

Amphibians

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Amphibians of the Angeac bed
Genus Species Location Stratigraphic position Abundance Notes Images
Albanerpetontidae Indeterminate "dentaries, premaxillae, maxillae, vertebrae and forelimb bones"
Anura Indeterminate Fragmentary bones
?Caudata Indeterminate Vertebra An assignment to Squamata cannot be excluded

Turtles

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Turtles of the Angeac bed
Genus Species Location Stratigraphic position Abundance Notes Images
Pleurosternon P. bullockii At least 12 individuals as well as one complete shell Pleurosternid paracryptodire
Hylaeochelys H. belli? "many isolated plates and one incomplete specimen discovered in 2018, consisting of parts of the plastron, some peripherals and both humeri" Thalassochelydian, represented by juveniles
Helochelydridae Indeterminate "incomplete isolated shell elements covered by typical tubercles, pustules and crests"

Lepidosauria

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Lepidosaurs of the Angeac bed
Genus Species Location Stratigraphic position Abundance Notes Images
cf. Opisthias Indeterminate "posterior dentary fragment bearing two preserved acrodont teeth in addition to seven broken teeth" Sphenodontian
Paramacellodus Indeterminate "jaw fragment bearing two closely spaced teeth" Paramacellodid lizard

Choristodera

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Choristoderes of the Angeac bed
Genus Species Location Stratigraphic position Abundance Notes Images
cf. Cteniogenys Indeterminate "A characteristic robust vertebra, as well as a smaller vertebra that probably belongs to a juvenile individual"

Pterosaurs

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Pterosaurs of the Angeac bed
Genus Species Location Stratigraphic position Abundance Notes Images
Pterosauria Indeterminate Teeth of three distinct morphotypes, at least some of which belong to pterodactyloids

Crocodyliforms

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Crocodyliforms of the Angeac bed
Genus Species Location Stratigraphic position Abundance Notes Images
Goniopholis Indeterminate "skull, mandibles, vertebrae, limb, girdle bones and osteoderms" belonging to a single individual, along with other isolated remains Goniopholidid
Pholidosaurus Teeth Pholidosaurid
Theriosuchus Teeth Atoposaurid
Bernissartiidae Teeth

Dinosaurs

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Ornithischians

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Ornithischians of the Angeac bed
Genus Species Location Stratigraphic position Abundance Notes Images
cf. Echinodon Indeterminate Two premaxillary teeth Heterodontosaurid
Dacentrurus sensu lato 84 skeletal elements, including vertebrae, ribs, several phalanges and elements of the braincase, likely belonging to a single individual Dacentrurine stegosaur
Hypsilophodontidae Premaxillary tooth, maxillary tooth and dentary tooth Similar to Hypsilophodon
Camptosauridae Dentary tooth, femur
Ankylosauria Tooth and osteoderm

Sauropods

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Sauropods of the Angeac bed
Genus Species Location Stratigraphic position Abundance Notes Images
Turiasauria (="Francoposeidon") Indeterminate "braincase, some skull bones, teeth, cervical, dorsal and caudal vertebrae, chevrons, pelvic girdle and all the limb bones" alongside isolated teeth, belonging to at least 7 individuals All belongs to a single taxon
Macronaria Indeterminate Two teeth Probably closely related to Camarasaurus

Theropods

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Theropods of the Angeac bed
Genus Species Location Stratigraphic position Abundance Notes Images
cf. Nuthetes Indeterminate Several teeth Dromaeosaurid
Ornithomimosauria Undescribed Isolated remains of at least 70 individuals representing almost all of the skeleton Most abundant fossil at the site
?Megalosauridae Indeterminate large (> 3 cm) blade–like teeth Likely assignable to a single taxon, possibly assignable to other groups of basal tetanurans
Tyrannosauroidea Indeterminate 8 teeth
Archaeopterygidae Indeterminate 5 teeth

Mammals

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Mammals of the Angeac bed
Genus Species Location Stratigraphic position Abundance Notes Images
Thereuodon T. cf. taraktes Isolated tooth crown Symmetrodont
?Gobiconodon Indeterminate Gobiconodontid
?Triconodon Almost complete tooth Triconodontid
Sunnyodon Indeterminate Premolar ?Paulchoffatiid Multituberculate
Spalacotherium S. evansae Three teeth Spalacotheriid
Peramus Indeterminate Peramurid
Dryolestidae Indeterminate two fragmentary molars Closely related to Guimarotodus and Phascolestes
Pinheirodontidae Indeterminate Numerous teeth Multituberculate

References

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  1. ^ a b 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 turnover at the J/K boundary. Geodiversitas, Museum National d’Histoire Naturelle Paris, In press. ffhal-03264773f
  2. ^ Néraudeau, D.; Allain, R.; Ballèvre, M.; Batten, D.J.; Buffetaut, E.; Colin, J.P.; Dabard, M.P.; Daviero-Gomez, V.; El Albani, A.; Gomez, B.; Grosheny, D. (October 2012). "The Hauterivian–Barremian lignitic bone bed of Angeac (Charente, south-west France): stratigraphical, palaeobiological and palaeogeographical implications". Cretaceous Research. 37: 1–14. doi:10.1016/j.cretres.2012.01.006.