The Lecho Formation is a geological formation in Argentina whose strata date back to the Late Cretaceous

Late Cretaceous

The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...

. Dinosaur remains are among the fossils that have been recovered from the formation.

According to Frankfurt and Chiappe (1999), the Lecho Formation is located in northwestern Argentina and is composed of reddish sandstones. The Lecho is part of the Upper/Late Cretaceous Balbuena Subgroup (Salta Group), which is a near-border stratigraphic unit of the Andean sedimentary basin. The paleoenvironment was a fluvio-lacustrine coastal plain. Fossils from this formation include the titanosaur

Titanosaur

Titanosaurs were a diverse group of sauropod dinosaurs, which included Saltasaurus and Isisaurus. It includes some of the heaviest creatures ever to walk the earth, such as Argentinosaurus and Paralititan — which some believe have weighed up to 100 tonnes...

 Saltasaurus

Saltasaurus

Saltasaurus is a genus of titanosaurid sauropod dinosaur of the Late Cretaceous Period. Relatively small among sauropods, though still massive by the standards of modern creatures, Saltasaurus was characterized by a diplodocid-like head...

along with a variety of avian

Avian

Avian may refer to:* Bird* Avian , an American metal band* AVIAN International, major international company headquartered in Hungary.* Aviano or Avian, an Italian city...

 and non-avian theropods.

|

Vertebrate paleofauna

Dinosaur Dinosaur Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of... s reported from the Lecho Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Avisaurus Avisaurus Avisaurus is a genus of enantiornithine bird from the Late Cretaceous of North America.Two species are known; the type species A. archibaldi and A. gloriae...	A. archibaldi
Enantiornis Enantiornis Enantiornis is a genus of predatory enantiornithine bird. The type and only currently accepted species E. leali is from Late Cretaceous rocks at El Brete, Argentina....	E. leali			"Postcranial elements."
Lectavis Lectavis Lectavis is a genus of enantiornithine bird. Its fossil bones were recovered from the Late Cretaceous Lecho Formation at estancia El Brete, Argentina...	L. bretincola			"Tarsometatarsus and tibiotarsus."
Noasaurus Noasaurus Noasaurus is the name given to a carnivorous dinosaur genus of the late Campanian-Maastrichtian...	N. leali			Isolated elements from the head and foot, as well as a verebral arch. A putative oviraptorosaurian cervical vertebra is likely to belong to this taxon.
Saltasaurus Saltasaurus Saltasaurus is a genus of titanosaurid sauropod dinosaur of the Late Cretaceous Period. Relatively small among sauropods, though still massive by the standards of modern creatures, Saltasaurus was characterized by a diplodocid-like head...	S. loricatus			"Partial skeletons of at least [six] individuals, including jaws and armor."
Soroavisaurus Soroavisaurus Soroavisaurus australis was an enantiornithine bird related to Avisaurus. It lived during the Late Cretaceous of Argentina.S. australis is known from fossils collected from the Lecho Formation of Estancia El Brete, in the southern tip of the province of Salta, Argentina...	S. australis			"Tarsometatarsus and phalanges."
Yungavolucris Yungavolucris Yungavolucris is a monotypic genus of enantiornithine bird. It contains the single species Yungavolucris brevipedaliswhich lived in the Late Cretaceous...	Y. brevipedalis			"Tarsometatarsi."