# Portezuelo Formation

The Portezuelo Formation is a geologic formation of Late Cretaceous (Late Turonian to Early Coniacian) age, outcropping in the Mendoza, Río Negro and Neuquén provinces of Argentina. It is the fourth-oldest formation in the Neuquén Group and the older of the two formations in the Río Neuquén Subgroup. Formerly, that subgroup was treated as a formation, and the Portezuelo Formation was known as the Portezuelo Member.

## Description

The type locality of the Portezuelo Formation is the mountain range known as Sierra del Portezuelo in Neuquén Province. This formation conformably overlies the Lisandro Formation of the Río Limay Subgroup. In the top layers it grades into the Plottier Formation, the younger formation within the Río Neuquén Subgroup.
Sandstones and siltstones, probably deposited under fluvial conditions, make up the Portezuelo Formation. There are also occasional cemented claystone deposits, as well as numerous paleosols (fossil soils). The formation varies between 95 and 130 metres (312 and 427 ft) thick throughout its range.

## Fossil content

Many dinosaur fossils have recently been described from this formation, as well as remains of several other types of animals:
* teleosteid fish including Leufuichthys
* ceratodontiform lungfish including Chaoceratodus
* abundant and diverse turtles including Baalemys, Portezueloemys and a species of Prochelidella
* abelisauroid theropods (, a possible noasaurid and an abelisaurid)
* several other theropods, including a modern, possibly galliform bird
* ornithopods including possible iguanodonts

### Dinosaurs
#### Ornithischians

| Color key Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon | Notes Uncertain or tentative taxa are in small text; crossed out taxa are discredited. |
Ornithischians of the Portezuelo Formation :
| Taxa | Species | Locality | Stratigraphic unit | Material | Notes | Images |
| Macrogryphosaurus | M. gondwanicus | The Mari Menuco lake | | An incomplete skeleton of an adult individual which includes an almost complete vertebral column, eight cervical vertebrae, 14 dorsal vertebrae (complete series), six sacral vertebrae, thirteen caudal vertebrae, a cervical rib, eleven dorsal ribs; nine haemal arches, sternum, right and left pelvic girdles, and three thoracic mineralized plates. | An elasmarian ornithopod. | |

#### Sauropods

| Color key Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon | Notes Uncertain or tentative taxa are in small text; crossed out taxa are discredited. |
Sauropods of the Portezuelo Formation :
| Taxa | Species | Locality | Stratigraphic unit | Material | Notes |
| Baalsaurus | B. mansillai | | | A mostly complete right dentary | A titanosaur |
| Futalognkosaurus | F. dukei | Futalognko quarry | | Atlas, axis, five anterior, four middle, and three poste-rior cervicals; 10 dorsals; ribs; complete sacrum; bothilia; right pubis and ischium; and one anterior caudal | A titanosaur |
| Malarguesaurus | M. florenciae | | Upper and Lower parts | A holotype consists of tail vertebrae, chevrons, ribs, and limb bones | A titanosaur |
| Muyelensaurus | M. pecheni | Loma del Lindero site | | A braincase including partial frontal and parietal, basioccipital, incomplete basipterigoid process, supraoccipital, exoccipital, basisphenoidals tubers, orbitosphenoids, and incomplete parasphenoids. | A titanosaur |

#### Theropods

Theropods of the Portezuelo Formation :
| Taxa | Species | Locality | Stratigraphic unit | Material | Notes | Images |
| Elemgasem | E. nubilus | Sierra del Portezuelo | Lower | A holotype consists of partial axial and appendicular elements, including cervical and caudal vertebrae, right femur, left tibia, right and left fibula, left astragalus-calcaneum, metatarsals, and various pedal phalanges | A abelisaur | Elemgasem nubilus Megaraptor namunhuaiquiiNeuquenraptor argentinus Pamparaptor micros Patagonykus puertai Unenlagia comahuensis |
| Megaraptor | M. namunhuaiquii | Sierra del Portezuelo | | A complete front limb, right ulna, and left manual phalanx. | A megaraptorid | Elemgasem nubilus Megaraptor namunhuaiquiiNeuquenraptor argentinus Pamparaptor micros Patagonykus puertai Unenlagia comahuensis |
| Neuquenraptor | N. argentinus | Sierra del Portezuelo | | A holotype consists of fragments of cervical vertebra, dorsal ribs, haemal arches, left proximal radius, right femur and distal tibia, proximal tarsals, and most of the foot of the left hindlimb. | A dromaeosaurid | Elemgasem nubilus Megaraptor namunhuaiquiiNeuquenraptor argentinus Pamparaptor micros Patagonykus puertai Unenlagia comahuensis |
| Pamparaptor | P. micros | Baal Quarry | | A holotype consists of three metatarsals, a complete second toe including the ungual, and two phalanges each from the third and fourth toes from the left foo | A dromaeosaurid | Elemgasem nubilus Megaraptor namunhuaiquiiNeuquenraptor argentinus Pamparaptor micros Patagonykus puertai Unenlagia comahuensis |
| Patagonykus | P. puertai | Los Barriales Lake. | | An incomplete but well-preserved skeleton consists of multiple vertebrae, the coracoids, a partial forelimb, pelvic girdle, and hindlimbs | An alvarezsaur. | Elemgasem nubilus Megaraptor namunhuaiquiiNeuquenraptor argentinus Pamparaptor micros Patagonykus puertai Unenlagia comahuensis |
| Unenlagia | U. comahuensis | Sierra del Portezuelo | Upper | A partial skeleton lacking the skull but including vertebrae, a sacrum, ribs, chevrons, a scapula, a humerus, a partial pelvis, a femur and a tibia | A dromaeosaurid | Elemgasem nubilus Megaraptor namunhuaiquiiNeuquenraptor argentinus Pamparaptor micros Patagonykus puertai Unenlagia comahuensis |
| Unenlagia | U. paynemili | Futalognko site | Upper | Several paratypes consists of a partial skeleton consisting of a humerus, vertebrae, claw, phalanx, and two pubes. | A dromaeosaurid | Elemgasem nubilus Megaraptor namunhuaiquiiNeuquenraptor argentinus Pamparaptor micros Patagonykus puertai Unenlagia comahuensis |

### Reptiles

Reptiles of the Portezuelo Formation :
| Taxa | Species | Locality | Stratigraphic unit | Material | Notes |
| Comahuesuchus | C. bonapartei | The Futalognko quarry | Upper | A partially preserved (cranial-most region) of the right mandible | A notosuchian crocodylomorphs. |
| Lomasuchus | L. palpebrosus | Loma de la Lata | | | A peirosaurid notosuchian. |
| Patagosuchus | P. anielensis | Baal Quarry, Loma de la Lata | | A fragmentary left dentary and splenial, the right maxilla and right jugal bone, a back vertebra, a back osteoderm and the right humerus. | A peirosaurid crocodyliform. |

### Pterosaurs

Pterosaurs of the Portezuelo Formation :
| Taxa | Species | Locality | Stratigraphic unit | Material | Notes | Images |
| Argentinadraco | A. barrealensis | Centro Paleontológico Lago Barreales | Upper | A single partial lower jaw, missing the rear end | An azdarchoid pterosaur. | |