Blesa Formation
# Blesa Formation

The Blesa Formation is a geological formation in Teruel and La Rioja, Spain whose strata date back to the Barremian of the Early Cretaceous. Dinosaur remains as well as eggs are among the fossils that have been recovered from the formation. Along with the fragmentary anhanguerian pterosaur Iberodactylus. While the lower and upper parts of the formation were deposited in a continental setting, the middle portion of the formation is largely nearshore marine, with remains of plesiosaurs.

## Stratigraphy and Lithology

The Belsa Formation is found within the Maestrazgo Basin. Within the stratigraphic sequence it overlies Jurassic rocks in a syn-rift unconformity, and underlies the Alacón Formation.

The formation is up to 150 metres thick and is divided into three distinct unconformity bounded units, which are called the Lower, Middle and Upper Blesa Sequences. The Lower Blesa sequence varies greatly in thickness from less than 10 m up to 100 m is divided up into two members, the lower Cabezo Gordo Member, which consists of red clays and the upper Morenillo Member, which consists of limestones and marls, both of these sequences were deposited in a continental setting. The Middle Blesa Sequence is of a fairly uniform 25-50 metre thickness. Most of the sequence consists of the Josa Member, which consists of oyster rich marls and limestones deposited in a coastal or shallow restricted bay environment. The Upper Blesa Sequence is of variable thickness from 15–70 m. The lower 1–10 m consists of continentally derived clays and marls with sandstone and conglomerate intercalations while the upper 10–60 m are dominated by carbonates.

## Vertebrate paleofauna

### Reptiles

Reptiles of the Blesa Formation :

| Taxa | Species | Presence | Material | Notes |
| - | - | - | - | - |
| Iguanodontia | Indeterminate | Lower Blesa Sequence | | 3 distinct taxa, one of which has affinities with Delapparentia |
| Iguanodontia | Unnamed | Upper Blesa Sequence | | "Vertebrae, ribs, left illium, partial sacrum, and partial left tibia." |
| Ankylosauria | Indeterminate | Lower Blesa Sequence | "Isolated teeth, dermal plates and vertebra" | |
| Spinosauridae | Indeterminate | Lower, Upper Blesa Sequence | Isolated Teeth | |
| Dromaeosauridae | Indeterminate | Lower Blesa Sequence | Isolated Teeth | |
| ?Carcharodontosauridae | Indeterminate | Lower, Upper Blesa Sequence | Isolated Teeth | |
| Euhelopidae | Indeterminate | Lower Blesa Sequence | Isolated Teeth | |
| Sauropoda | Indeterminate | Lower Blesa Sequence, La Cantalera-1 | Post-cranial material | |
| Crocodylomorpha | Indeterminate | Lower Blesa Sequence | | Possibly four distinct taxa |
| Plesiosauria | Indeterminate | Middle Blesa Sequence | | |

**Pterosaurs**

Pterosaurs of the Blesa Formation :

| Taxa | Species | Presence | Material |
| - | - | - | - |
| Istiodactylidae | Indeterminate | Lower Blesa Sequence | Isolated Teeth |
| Ornithocheiridae | Indeterminate | Lower Blesa Sequence | Isolated Teeth |
| Iberodactylus | I. andreui | Middle Blesa Sequence | Partial skull |

### Mammals

Mammals of the Blesa Formation :

| Taxa | Species | Presence | Material | Notes | Images |
| - | - | - | - | - | - |
| Cantalera | C. abadi | Lower Blesa Sequence | Teeth | Pinheirodontid | |
| Eobataar | Indeterminate | Lower Blesa Sequence | Teeth | | |

## Correlation

Early Cretaceous stratigraphy of Iberia :

| Ma | Age | Paleomap \ Basins | Cantabrian | Olanyà | Cameros | Maestrazgo | Oliete | Galve | Morella | South Iberian | Pre-betic | Lusitanian |
| - | - | - | - | - | - | - | - | - | - | - | - | - |
| 100 | Cenomanian | | La Cabana | Sopeira | Utrillas | Utrillas | Mosquerela | | | | | Caranguejeira |
| 100 | Cenomanian | | Altamira | Sopeira | Utrillas | Utrillas | Utrillas | | | | | | | Caranguejeira |
| 100 | Cenomanian | | Eguino | Sopeira | Utrillas | Utrillas | Utrillas | | | | | Caranguejeira |
| 125 | Albian | | Ullaga - Balmaseda | Lluçà | Utrillas | Utrillas | Utrillas | | | Traiguera | | Caranguejeira |
| 125 | Albian | | Monte Grande | Lluçà | Escucha | Escucha | Escucha | | | Jijona | | Caranguejeira |
| 125 | Albian | | Itxina - Miono | Lluçà | Escucha | Escucha | Escucha | | | | | Caranguejeira |
| 125 | Aptian | | Valmaseda - Tellamendi | Lluçà | Ol Gp. - Castrillo | Benassal | Escucha | Benassal | | | | Olhos |
| 125 | Aptian | | Valmaseda - Tellamendi | Font | En Gp. - Leza | Morella/Oliete | Oliete | Villaroya | Morella | Capas Rojas | | Almargem |
| 125 | Aptian | | Patrocinio - Ernaga | Senyús | En Gp. - Jubela | Forcall | Forcall | Forcall | Morella | Villaroya | Upper Bedoulian | Figueira |
| 125 | Barremian | | Vega de Pas | Cabó | Abejar | Xert | Alacón | Xert | Morella | Huérguina | Upper Bedoulian | Assises |
| 125 | Barremian | | Vega de Pas | Prada | Abejar | Artoles | Artoles | Artoles | Morella | Collado | Moutonianum | Papo Seco |
| 125 | Barremian | | Vega de Pas | Rúbies | Tera Gp. - Golmayo | Alacón/Blesa | Blesa | Camarillas | Mirambel | Collado | Moutonianum | Papo Seco |
| 150 | Hauterivian | | Vega de Pas | Rúbies | Ur Gp. - Pinilla | Llacova | Blesa | Castellar | Tera Gp. - Pinilla | Villares | | Porto da Calada |
| 150 | Hauterivian | | Vega de Pas | Rúbies | Ur Gp. - Pinilla | Llacova | hiatus | Castellar | | Villares | | Porto da Calada |
| 150 | Hauterivian | | Vega de Pas | Rúbies | Ur Gp. - Pinilla | Huerva | hiatus | Castellar | Gaita | | | Porto da Calada |
| 150 | Valanginian | | Villaro | Rúbies | Ur Gp. - Larriba | Huerva | hiatus | Castellar | Ped Gp. - Hortigüela | | | Porto da Calada |
| 150 | Valanginian | | Villaro | Rúbies | Ped Gp. - Hortigüela | Huerva | hiatus | Castellar | Ped Gp. - Piedrahita | | | Porto da Calada |
| 150 | Valanginian | | Villaro | Rúbies | Peñacoba | Huerva | hiatus | Galve | Ped Gp. - Piedrahita | Miravetes | | Porto da Calada |
| 150 | Berriasian | | Cab Gp. - Arcera | Rúbies | Valdeprado | hiatus | hiatus | Alfambra | Ped Gp. - Piedrahita | Miravetes | | Porto da Calada |
| 150 | Berriasian | | Cab Gp. - Arcera | | TdL Gp. - Rupelo | hiatus | hiatus | Arzobispo | hiatus | Tollo | | Porto da Calada |
| 150 | Berriasian | | Cab Gp. - Arcera | | On Gp. - Huérteles Sierra Matute | hiatus | hiatus | Arzobispo | hiatus | Tollo | | Porto da Calada |
| 150 | Tithonian | | Lastres | | Tera Gp. - Magaña | hiatus | Higuereles | Higuereles | hiatus | Tera Gp. - Magaña | | Lourinhã |
| 150 | Tithonian | | Lastres | | Tera Gp. - Magaña | hiatus | Higuereles | Higuereles | Arzobispo | Tera Gp. - Magaña | | Lourinhã |
| 150 | Tithonian | | Lastres | | Ágreda | hiatus | Higuereles | Higuereles | Arzobispo | Tera Gp. - Magaña | | Lourinhã |
| Legend | Legend | Major fossiliferous, oofossiliferous, ichnofossiliferous, coproliferous, minor formation | Major fossiliferous, oofossiliferous, ichnofossiliferous, coproliferous, minor formation | Major fossiliferous, oofossiliferous, ichnofossiliferous, coproliferous, minor formation | Major fossiliferous, oofossiliferous, ichnofossiliferous, coproliferous, minor formation | Major fossiliferous, oofossiliferous, ichnofossiliferous, coproliferous, minor formation | Major fossiliferous, oofossiliferous, ichnofossiliferous, coproliferous, minor formation | Major fossiliferous, oofossiliferous, ichnofossiliferous, coproliferous, minor formation | Major fossiliferous, oofossiliferous, ichnofossiliferous, coproliferous, minor formation | Major fossiliferous, oofossiliferous, ichnofossiliferous, coproliferous, minor formation | Major fossiliferous, oofossiliferous, ichnofossiliferous, coproliferous, minor formation | Major fossiliferous, oofossiliferous, ichnofossiliferous, coproliferous, minor formation | Major fossiliferous, oofossiliferous, ichnofossiliferous, coproliferous, minor formation |
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