The Crato Formation is a geologic formation of Early Cretaceous

Early Cretaceous

The Early Cretaceous or the Lower Cretaceous , is the earlier or lower of the two major divisions of the Cretaceous...

 age in northeastern Brazil

Brazil

Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

's Araripe Basin. It is an important Lagerstätte (undisturbed fossil accumulation) for palaeontologists. The strata were laid down mostly during the early Albian

Albian

The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous epoch/series. Its approximate time range is 112.0 ± 1.0 Ma to 99.6 ± 0.9 Ma...

 age, about 108 million years ago, in a shallow inland sea. At that time, the South Atlantic

Atlantic Ocean

The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

 was opening up in a long narrow shallow sea.

The Crato Formation earns the designation of Lagerstätte due to an exceedingly well preserved and diverse fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

 faunal assemblage. Some 25 species of fossil fishes are often found with stomach contents preserved, enabling paleontologists to study predator-prey relationships in this ecosystem. There are also fine examples of pterosaur

Pterosaur

Pterosaurs were flying reptiles of the clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period . Pterosaurs are the earliest vertebrates known to have evolved powered flight...

s, reptiles and amphibians, invertebrates (particularly insects), and plants. Even dinosaurs are represented: a new maniraptor was described in 1996. The unusual taphonomy

Taphonomy

Taphonomy is the study of decaying organisms over time and how they become fossilized . The term taphonomy was introduced to paleontology in 1940 by Russian scientist Ivan Efremov to describe the study of the transition of remains, parts, or products of organisms, from the biosphere, to the...

 of the site resulted in limestone accretions that formed nodules around dead organisms, preserving even soft parts of their anatomy.

History

Fish fossils in the area were noted in 1823. When they were first methodically published, in 1993, the Crato Formation limestones provided a new site for pterosaur

Pterosaur

Pterosaurs were flying reptiles of the clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period . Pterosaurs are the earliest vertebrates known to have evolved powered flight...

s, one that also preserved insects that fell into a brackish lagoon and semionotid fish preserved in phosphatized nodules. The fossils are usually compacted and preserved in layers of limestone. Fossil Odonata

Odonata

Odonata is an order of insects, encompassing dragonflies and damselflies . The word dragonfly is also sometimes used to refer to all Odonata, but the back-formation odonate is a more correct English name for the group as a whole...

 (dragonflies

Dragonfly

A dragonfly is a winged insect belonging to the order Odonata, the suborder Epiprocta or, in the strict sense, the infraorder Anisoptera . It is characterized by large multifaceted eyes, two pairs of strong transparent wings, and an elongated body...

) and damselflies are especially rich in the Crato lagerstätte: currently 384 specimens have been recovered, 264 adults and 120 larvae. Hemiptera (true bugs) and Orthoptera (grasshoppers and crickets) are also abundant in number of species and in number of specimens. There are also plant remains.

Local mining activities for cement and construction damage the sites. Trade in illegally-collected fossils has sprung up in the last decade, driven by the remarkable state of preservation and beauty of these fossils and amounting to a considerable local industry. An urgent preservation program is being called for by paleontologists.



In addition, the weathering

Weathering

Weathering is the breaking down of rocks, soils and minerals as well as artificial materials through contact with the Earth's atmosphere, biota and waters...

 of Crato and Santana Formation rocks has contributed soil

Soil

Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...

 conditions unlike elsewhere in the region. The Araripe Manakin

Araripe Manakin

The Araripe Manakin is a critically endangered bird from the family of Manakins . It was discovered in 1996 and scientifically described in 1998. The species epithet commemorates Brazilian zoologist and wildlife filmmaker Werner Bokermann, who died in 1995...

 (Antilophia bokermanni) is a very rare bird that was discovered only in the late 20th century; it is not known from anywhere outside the characteristic forest that grows on the Chapada do Araripe

Chapada do Araripe

The Chapada do Araripe, also known as the Serra do Araripe, is a chapada in northeastern Brazil. The chapada forms the boundary of Ceará and Pernambuco states, and forms the watershed between the Jaguaribe River of Ceará, which flows northward into the Atlantic, and the much larger basin of the...

 soils formed ultimately from Crato and Santana Formation rocks.

The Crato Formation has often historically been considered the lowest member of the Santana Formation

Santana Formation

The Santana Formation is a geologic Lagerstätte in northeastern Brazil's Araripe Basin where the states of Pernambuco, Piauí and Ceará come together. The geological formation, named after the village of Santana do Cariri, lies at the base of the Araripe Plateau...

 (or, alternatively, the Araripina Formation). The Crato Member is the product of a single phase, where complicated sequence of sediment strata

Stratum

In geology and related fields, a stratum is a layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers...

 reflect changeable conditions in the opening sea. The age of this strata has been controversial, though most workers have agreed that it lies on or near the Aptian-Albian boundary, about 112 million years ago.

The extent of the Crato unit and its relationship to the Santana Formation had long been ill defined. It was not until a 2007 volume on the unit by Martill, Bechly and Loveridge that the Crato Formation was given a formal type locality, and was formally made a distinct formation separate from the Santana, which is about 10 Ma younger.

Amphibians

Amphibian Amphibian Amphibians , are a class of vertebrate animals including animals such as toads, frogs, caecilians, and salamanders. They are characterized as non-amniote ectothermic tetrapods... s of the Crato Formation
Genus	Species	Presence	Description	Images
Arariphrynus	Arariphrynus placidoi
Cratia Cratia Cratia is an extinct frog which existed in Brazil during the lower Cretaceous period. It was named by Ana M. Báez, Geraldo J.B. Moura and Raúl O. Gómez in 2009, and the type species is Cratia gracilis....	Cratia gracilis
Eurycephalella Eurycephalella Eurycephalella is an extinct genus of frog which existed in what is now Brazil during the lower Cretaceous period. It was named by Ana M. Báez, Geraldo J.B. Moura and Raúl O. Gómez in 2009, and the type species is Eurycephalella alcinae.-Discovery:...	Eurycephalella alcinae
Pipoidea Pipoidea Pipoids are a superfamily of frogs....	Possible indeterminate pipoid remains.

Birds and other dinosaurs

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 and bird Bird Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from... s of the Crato Formation
Genus	Species	Presence	Notes	Images
?Spinosauroidea	?Spinosaur species		Isolated tooth
?Enantiornithes Enantiornithes Enantiornithes is an extinct group of primitive birds. They were the most abundant and diverse avialans of the Mesozoic. Almost all retained teeth and clawed fingers on each wing, but otherwise looked much like modern birds externally. Over 50 species of Enantiornithines have been named, but some...	Enantiornithine species		Undescribed species
?Avialae Avialae Avialae is a clade of dinosaurs containing their only living representatives, birds , and the most immediate extinct relatives of birds.-Competing definitions:...	?Avialan species		Numerous isolated feathers

Crurotarsans

Crocodylomorphs of the Crato Formation
Genus	Species	Presence	Description	Images
Susisuchus Susisuchus Susisuchus is an extinct genus of mesoeucrocodylian crocodyliform from the Early Cretaceous of Brazil. Fossils have been found from the Nova Olinda Member of the Aptian-age Crato Formation in the Araripe and Lima Campos Basins of northeastern Brazil...	Susisuchus anatoceps
	cf. Susisuchus sp.		Undescribed species

Insects

Insect Insect Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae... s of the Crato Formation
Genus	Species	Presence	Description	Images
Rafaelia	Rafaelia maxima	Crato member.	Neuropterida Neuropterida The Neuropterida are a clade of holometabolous insects. Well-known members are the lacewings, antlions and dobsonflies.Historically, they were known as Neuroptera, but this name nowadays refers to lacewings and their relatives only, which formerly were known as Planipennia...  incertae sedis Incertae sedis , is a term used to define a taxonomic group where its broader relationships are unknown or undefined. Uncertainty at specific taxonomic levels is attributed by , , and similar terms.-Examples:*The fossil plant Paradinandra suecica could not be assigned to any...

Pterosaurs

Pterosaur Pterosaur Pterosaurs were flying reptiles of the clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period . Pterosaurs are the earliest vertebrates known to have evolved powered flight... s of the Crato Formation
Genus	Species	Presence	Description	Images
Arthurdactylus Arthurdactylus Arthurdactylus is a genus of pterodactyloid pterosaur from the Early Cretaceous-age Crato Formation of Brazil. It was a large animal, with a wingspan of 4.6 meters....	Arthurdactylus conandoylei
Brasileodactylus Brasileodactylus Brasileodactylus is the name assigned to the remains of a pterosaur from the Lower Santana formation of the Aptian of Chapada do Araripe, Ceará, Brazil....	Brasileodactylus sp.
Lacusovagus Lacusovagus Lacusovagus is a genus of azhdarchoid pterodactyloid pterosaur from the Lower Cretaceous of Brazil. It is based on SMNK PAL 4325, a partial upper jaw comprising sections of the skull in front of the eyes...	Lacusovagus magnificens	Nova Olinda Member
Ludodactylus Ludodactylus Ludodactylus was a genus of ornithocheirid pterodactyloid pterosaur from the Aptian-age Lower Cretaceous Crato Formation of Ceará, Brazil....	Ludodactylus sibbicki
Tupandactylus Tupandactylus Tupandactylus is a genus of tapejarid pterodactyloid pterosaur from the Early Cretaceous Crato Formation of Brazil. It is notable for its large cranial crest, composed partly of bone and partly of soft tissue...	Tupandactylus imperator
	Tupandactylus navigans
?Tupuxuara Tupuxuara Tupuxuara is a genus of large, crested, toothless pterodactyloid pterosaur.The genus was in 1988 named and described by Alexander Kellner and Diogenes de Almeida Campos. The type species is Tupuxuara longicristatus. The genus name refers to a familiar spirit from the mythology of the Tupi...	?Tupuxuara sp.