Santana Formation

Amphibians , such as frogs, toads, salamanders, newts, and caecilians, are ectothermic animals that metamorphose from a juvenile water-breathing form, to an adult air-breathing form. Though amphibians typically have four limbs, the Caecilians are notable for being limbless. Unlike other land...

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The Santana Formation is a geologic Lagerstätte (undisturbed fossil accumulation) in northeastern Brazil

Brazil

Brazil , officially the Federative Republic of Brazil , is a country in South America. It is the fifth largest country by geographical area, occupying nearly half of South America, the fifth most populous country, and the fourth most populous democracy in the world. Bounded by the Atlantic Ocean...

's Araripe Basin where the states of Pernambuco

Pernambuco

Pernambuco is a state of Brazil, located in the Northeast region of the country. To the north are the states of Paraíba and Ceará, to the west is Piauí, to the south are Alagoas and Bahia, and to the east is the Atlantic Ocean. There are about 187 kilometers of beaches, some of the most...

, Piauí

Piauí

Piauí is one of the states of Brazil, located in the northeastern part of the country.Piauí has the shortest coastline of any of the non-landlocked Brazilian states at 66 km , and the capital, Teresina, is the only state capital in the north east to be located inland...

 and Ceará

Ceará

Ceará is one of the 26 states of Brazil, located in the northeastern part of the country, on the Atlantic coast. It is one of the main tourist destinations of Brazil.Literally, the name Ceará means "sings the jandaia"...

 come together. The geological formation, named after the village of Santana do Cariri, lies at the base of the Araripe Plateau. The strata were laid down during the early Cretaceous

Cretaceous

The Cretaceous , Latin language for "chalky", usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago . In the geologic timescale, the Cretaceous follows on the Jurassic period and is followed by the Paleogene period of the...

, specifically 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...

 to Cenomanian

Cenomanian

The Cenomanian is, in the ICS' geological timescale the oldest or earliest age of the Late Cretaceous epoch or the lowest stage of the Upper Cretaceous series. An age is a unit of geochronology: it is a unit of time; the stage is a unit in the stratigraphic column deposited during the corresponding...

, 108 to 92 million years ago, in a shallow inland sea. At that time, the South Atlantic was opening up in a long narrow shallow sea.

The Santana 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. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous rock formations and sedimentary layers is known as the fossil record...

 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...

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

Taphonomy

TaphonomyFrom greek Taphos; literally meaning 'study of the grave' is the study of decaying organisms over time and how they become fossilized...

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

The Crato Member is the product of a single phase in the Santana Formation, where complicated sequence of sediment strata

Stratum

In geology and related fields, a stratum is a layer of rock or soil with internally consistent characteristics that distinguishes it from contiguous layers. Each layer is generally one of a number of parallel layers that lie one upon another, laid down by natural forces. They may extend over...

 reflect changeable conditions in the opening sea.

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...

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...

 (dragonflies

Dragonfly

A dragonfly is a type of 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 decomposition of Earth's rocks, soils and minerals through direct contact with the planet's atmosphere. Weathering occurs in situ, or "with no movement", and thus should not be confused with erosion, which involves the movement of rocks and minerals by agents such as water, ice,...

 of 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. It is composed of particles of broken rock that have been altered by chemical and...

 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 Santana Formation rocks.

Amphibians

Amphibian Amphibian Amphibians , such as frogs, toads, salamanders, newts, and caecilians, are ectothermic animals that metamorphose from a juvenile water-breathing form, to an adult air-breathing form. Though amphibians typically have four limbs, the Caecilians are notable for being limbless. Unlike other land... s of the Santana Formation
Genus	Species	Presence	Description	Images
Arariphrynus	Arariphrynus placidoi	Stratigraphically present in the Crato Member.
Cratia	Cratia gracilis	Stratigraphically present in the Crato Member.
Eurycephalella	Eurycephalella alcinae	Stratigraphically present in the Crato Member.
Pipoidea	Possible indeterminate pipoid remains.	Stratigraphically present in the Crato Member.

Dinosaurs

Indeterminate remains of theropods, avialans, ornithischians, and possibly oviraptorosaurs have been found in Estado do Ceara, Brazil. An unnamed compsognathid has also been found in Estado do Ceara.

Dinosaur Dinosaur {{Otheruses}}{{pp-semi-protected|small=yes}}{{Otheruses}}{{pp-semi-protected|small=yes}}{{Taxobox|name = Dinosaurs|fossil_range = {{Fossil range|230|65|earliest=230|latest=0|PS= Descendant taxon Aves survives to present.}}|image = field_dinos_2.jpg... s and Bird Bird Birds are winged, bipedal, endothermic , vertebrate animals that lay eggs. There are around 10,000 living species, making them the most numerous tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Birds range in size from the Bee Hummingbird to the ... s of the Santana Formation
Genus	Species	Presence	Notes	Images
Angaturama Angaturama Angaturama is a genus of spinosaurid theropod from the Early Cretaceous Santana Formation of northeastern Brazil. The type specimen was discovered in a limestone nodule and consisted of the incomplete anterior portion of a skull. A description of the new species, A. limai by Alexander W.A...	A. limai	Geographically present in Estado do Ceara, Brazil.	Spinosauridae Spinosauridae Spinosauridae is a family of specialised theropod dinosaurs. Members of this family were large, bipedal predators with elongated, crocodile-like skulls, sporting conical teeth with no or only very tiny serrations. The front dentary teeth fanned out, giving the animal a characteristic look...
Irritator Irritator Irritator is a genus of spinosaurid dinosaur that lived in the early Cretaceous Period , around 110 million years ago. Current estimations indicate a length of 8 meters and a height of 3 meters . It was found in Brazil...	A. challengeri	Geographically present in Estado do Ceara, Brazil.	Spinosauridae Spinosauridae Spinosauridae is a family of specialised theropod dinosaurs. Members of this family were large, bipedal predators with elongated, crocodile-like skulls, sporting conical teeth with no or only very tiny serrations. The front dentary teeth fanned out, giving the animal a characteristic look...
Santanaraptor Santanaraptor Santanaraptor is a genus of theropod dinosaur that lived in South America during the Albian or Aptian stage of the Early Cretaceous, about 108 million years ago. Known from a partial juvenile specimen recovered with mineralized soft tissue, which was unearthed in 1996 from the Santana Formation of...	S. placidus	Geographically present in Estado do Ceara, Brazil.

Insects

Insect Insect Insects are arthropods, having a hard exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae. They are the most diverse group of animals on the planet and include more than a million species that are already described. Insects represent more than half of all... s of the Santana 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 Incertae sedis , abbreviated "inc. sed.", is a term used to define a taxonomic group where its broader relationships are unknown or undefined.-Examples:The taxonomy for humans is usually recognized as follows:...

Pterosaurs

Pterodactyls of the Santana Formation
Genus	Species	Presence	Description	Images
Araripedactylus Araripedactylus Araripedactylus was a large genus of pterodactyloid pterosaur, known from a single wing bone found in the Early Cretaceous-age Santana Formation of Brazil....	Araripedactylus dehmi
Araripesaurus Araripesaurus Araripesaurus was a pterosaur, belonging to the Pterodactyloidea, from the famous Santana Formation of Brazil, dating from the Lower Cretaceous....	Araripesaurus castilhoi
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
Cearadactylus Cearadactylus Cearadactylus is an extinct genus of large, Early Cretaceous pterosaur from South America. Although its classification remains uncertain, it is likely to be a member of the pterodactyloid family Ctenochasmatidae, and possibly the subfamily Gnathosaurinae.-Cearadactylus atrox:The type species is...	Cearadactylus atrox
Ludodactylus Ludodactylus Ludodactylus was a genus of ornithocheirid pterodactyloid pterosaur from the Aptian-age Lower Cretaceous Crato Formation of Ceará, Brazil....	Ludodactylus sibbicki
Ornithocheirus Ornithocheirus Ornithocheirus was a pterosaur from the Cretaceous period of Europe and South America...	Placeholder placeholder
"Pricesaurus Pricesaurus "Pricesaurus" is an informal name for a genus of pterodactyloid pterosaur from the Aptian-age Lower Cretaceous Santana Formation of Araripe, Brazil. Although it was first discussed as "Pricesaurus" in a 1986 abstract, virtually nothing is known about it. The suggested type species is "P.... "	"Pricesaurus megalodon"
Santanadactylus Santanadactylus Santanadactylus was a genus of pterodactyloid pterosaur from the Aptian-age Romualdo Member of the Lower Cretaceous Santana Formation, of Barra do Jardim, Araripe Plateau, Ceará Province, Brazil. Four species have been named, but today it is doubted they are part of the same genus...	Placeholder placeholder
Tupandactylus Tupandactylus Tupandactylus is a genus of tapejarid pterodactyloid pterosaur from the Early Cretaceous Santana Formation of Brazil...	Placeholder placeholder

Turtles

Turtle Turtle Turtles are reptiles of the order Testudines , characterised by a special bony or cartilaginous shell developed from their ribs that acts as a shield... s of the Santana Formation
Genus	Species	Presence	Description	Images
Santanachelys Santanachelys Santanachelys gaffneyi is the earliest known sea turtle. It is the only species in the genus Santanachelys, which itself is a member of the extinct family Protostegidae. The species was first described from a 20-centimeter long fossil specimen unearthed in 1998 in Eastern Brazil...			Protostegidae Protostegidae Protostegidae is a family of extinct marine turtles that lived during the Mesozoic Era. The family includes some of the largest sea turtles that ever existed. The largest, Archelon, had a head a meter long... , Cryptodira Cryptodira Cryptodira is the taxonomic suborder of Testudines that includes most living tortoises and turtles. Cryptodira differ from Pleurodira in that they lower their neck and pull the head straight back into the shell, instead of folding the neck sideways it is along the body under the shell's margin...

See also

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• List of fossil sites (with link directory)
• List of dinosaur-bearing rock formations

External links

• Santana Formation fossils
• geol/jgs/1996/00000153/00000001/15310005 "A new crested maniraptoran dinosaur from the Santana Formation"
• American Museum of Natural History: Brazilian fossil fishes
• Maria Somália Sales Viana and Virgínio Henrique Lopes Neumann, "The Crato Member of the Santana Formation, Ceará State"

Further reading

• David A. Grimaldi (ed.) 1990. Insects from the Santana Formation, Lower Cretaceous, of Brazil, Bulletin of the American Museum of Natural History no. 195
• John G. Maisey (ed.) 1991. Santana Fossils - An Illustrated Atlas (T.H.F. Publ.)
• David M. Martill, 1993. Fossils of the Santana and Crato Formations, Brazil (Field Guide to Fossils no. 5) (The Palaeontological Association) ISBN 0-901702-46-3
• David M. Martill, Günter Bechly and Robert F. Loverridge (eds) 2007. The Crato Fossil Beds of Brazil: Window into an Ancient World (Cambridge University Press) ISBN 978-0-521-85867-0

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