The Castrillo de la Reina Formation is a geological formation in

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , i ...

. It is late

Barremian The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma (million years ago) and 121.4 ± 1.0 Ma). It is a subdivision of the Early Cretaceous Epoch (or Lower Cretaceous Series). It is preceded ...

to early

Aptian The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago), a ...

in age. It interpreted as a fluvial deposit. It primarily consists of red clay, with ribbon shaped sandstone channel fills. The

rebbachisaurid Rebbachisauridae is a family of sauropod dinosaurs known from fragmentary fossil remains from the Cretaceous of South America, Africa, North America, Europe and possibly Central Asia. Taxonomy In 1990 sauropod specialist Jack McIntosh included t ...

dinosaur ''

Demandasaurus ''Demandasaurus'' (meaning " Demanda lizard") is a genus of rebbachisaurid sauropod dinosaur from early Cretaceous (late Barremian – early Aptian stage) deposits of Spain. ''Demandasaurus'' is known from an incomplete but associated skeleton t ...

'' occurs in the formation, alongside

somphospondylan Somphospondyli is an extinct clade of titanosauriform sauropods that lived from the Late Jurassic until the end of the Late Cretaceous, comprising all titanosauriforms more closely related to Titanosauria proper than Brachiosauridae. The remain ...

'' Europatitan'' as well as indeterminate small

ornithopod Ornithopoda () is a clade of ornithischian dinosaurs, called ornithopods (), that started out as small, bipedal running grazers and grew in size and numbers until they became one of the most successful groups of herbivores in the Cretaceous world ...

iguanodonts Iguanodontia (the iguanodonts) is a clade of herbivorous dinosaurs that lived from the Middle Jurassic to Late Cretaceous. Some members include ''Camptosaurus'', ''Dryosaurus'', ''Iguanodon'', ''Tenontosaurus'', and the hadrosaurids or "duck-bil ...

and

spinosaurid The Spinosauridae (or spinosaurids) are a clade or family of tetanuran theropod dinosaurs comprising ten to seventeen known genera. They came into prominence during the Cretaceous period. Spinosaurid fossils have been recovered worldwide, includi ...

s, the earliest known stem-

rhabdodontid Rhabdodontidae is a family of herbivorous iguanodontian ornithopod dinosaurs whose earliest stem members appeared in the middle of the Lower Cretaceous. The oldest dated fossils of these stem members were found in the Barremian Castrillo de la R ...

(indeterminate) and the lizard ''

Arcanosaurus ''Arcanosaurus'' is an extinct genus of varanoid lizard from the Early Cretaceous of Spain. It is known from 29 vertebrae that were found disarticulated but close together in a fossil locality called Viajete in the province of Burgos. The bones ...

''.

Correlation

References

{{reflist Geologic formations of Spain Lower Cretaceous Series of Europe Cretaceous Spain Aptian Stage Barremian Stage Shale formations Sandstone formations Alluvial deposits Fluvial deposits Paleontology in Spain