Crato Formation

The Crato Formation is a geologic formation of Early Cretaceous (Aptian) age in northeastern Brazil's Araripe Basin. It is an important Lagerstätte (undisturbed fossil accumulation) for palaeontologists. The strata were laid down mostly during the Aptian age, about 113 million years ago. It thought to have been deposited in a semi-arid lacustrine wetland environment.<ref>Ribeiro et al., 2021</ref>

The Crato Formation earns the designation of Lagerstätte due to an exceedingly well preserved and diverse fossil 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 pterosaurs, reptiles and amphibians, invertebrates (particularly insects), and plants. Even dinosaurs are represented: a new maniraptor was described in 1996. The unusual taphonomy of the site resulted in limestone accretions that formed nodules around dead organisms, preserving even soft parts of their anatomy.

History

Schematic development of the depositional environments of the Santana Group

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 pterosaurs, 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 (dragonflies) 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. Template:Clear

In addition, the weathering of Crato and Santana Formation rocks has contributed soil conditions unlike elsewhere in the region. The Araripe manakin (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 soils formed ultimately from Crato and Santana Formation rocks.

Definition

Lake level cyclicity in the Santana Group

Template:See also The Crato Formation has often historically been considered the lowest member of the Santana Formation (or, alternatively, the Araripina Formation) of the Araripe Group,<ref name="Scherer etal 2013 p28">Scherer et al., 2013, p. 28. Retrieved 2018-10-05.</ref> later redefined as the Romualdo Formation of the Santana Group.<ref name="Assine 1992 p291">Assine, 1992, p. 291. Retrieved 2018-10-05.</ref><ref name="Fabin etal 2018 p2050">Fabin et al., 2018, p. 2050. Retrieved 2018-10-05.</ref> The Crato Member is the product of a single phase, where complicated sequence of sediment strata 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.<ref name="Martill etal 2007">Martill et al., 2007. Retrieved 2018-10-06.</ref>

The extent of the Crato unit and its relationship to the Romualdo 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.<ref name="Martill etal 2007" /> The Crato Formation is considered time equivalent with the Paracuru Formation.<ref name="Leite da Silva 2003">Leite da Silva, 2003. Retrieved 2018-10-06.</ref>

Fossil content

Insects

(Note: Many more insects have been described than are present in the table below)

Insects of the Crato Formation
Genus	Species	Presence	Description	Images
Araripenymphes<ref name="Myskowiak 2016">Myskowiak, 2016</ref>	A. seldoni	Nova Olinda Member	A Cratosmylidae lacewing<ref>Template:Cite journal</ref>
Gracilepteryx	G. pulchra		An Eolepidopterigidae moth
Makarkinia<ref name="Bechly etal 2016">Bechly et al., 2016. Retrieved 2018-10-06.</ref>	M. adamsi M. kerneri		A Kalligrammatid lacewing
Mickoleitia	M. longimanus		A Coxoplectopteran insect	Mickoleitia longimanus
Netoxena	N. nana		An Eolepidopterigidae moth
Principiala<ref name="Makarkin Menon 2007">Makarkin & Menon, 2007. Retrieved 2018-10-06.</ref>	P. incerta		An Ithonidae lacewing, type species of Principiala
Psamateia	P. calipsa		An Eolepidopterigidae moth
Rafaeliana	R. maxima		Neuropterida incertae sedis
Undopterix	U. cariensis		An Eolepidopterigidae moth
Astraeoptera<ref name=":0">Template:Cite journal</ref>	A. vitrea		An Astraeopteridae mayfly.
	A. cretacica
	A. oligovenata
Eosophobia<ref name=":0" />	E. acuta		An Astraeopteridae mayfly.
Vulcanidris<ref>Template:Cite journal</ref>	V. cratensis		A hell ant

Arachnids

Arachnids of the Crato Formation
Genus	Species	Presence	Description	Images
Mesoproctus<ref>Template:Cite journal</ref>	M. rayoli		Whip Scorpion
Protoischnurus	P. axelrodorum		Scorpion
Cratosolpuga	C. wunderlichi		Solifuge

Fish

Fish of the Crato Formation
Genus	Species	Presence	Description	Images	Notes
Araripelepidotes	Araripelepidotes temnurus				Template:Center
Belonostomus	Belonostomus sp.				Template:Center
Calamopleurus	Calamopleurus cylindricus				Template:Center
Cladocyclus	Cladocyclus gardneri		An Ichthyodectidae fish		Template:Center
Cratoamia	Cratoamia gondwanica				Template:Center
Dastilbe	Dastilbe crandalli				Template:Center
Lepidotes	Lepidotes wenzae				Template:Center
Placidichthys	Placidichthys bidorsalis				Template:Center
Santanichthys	Santanichthys diasii				Template:Center

Amphibians

Amphibians of the Crato Formation
Genus	Species	Presence	Description	Images
Arariphrynus<ref name="Baez etal 2009">Báez et al., 2009. Retrieved 2018-10-06.</ref>	Arariphrynus placidoi<ref name="Baez etal 2009" />
Cratia<ref name="Baez etal 2009" />	Cratia gracilis<ref name="Baez etal 2009" />
Cratopipa<ref>Template:Cite journal</ref>	Cratopipa novaolindensis
Eurycephalella<ref name="Baez etal 2009" />	Eurycephalella alcinae<ref name="Baez etal 2009" />
Kururubatrachus<ref>Template:Cite journal</ref>	Kururubatrachus gondwanicus
Pipoidea<ref name="Baez etal 2009" />	Possible indeterminate pipoid remains.<ref name="Baez etal 2009" />

Squamata

Squamates of the Crato Formation
Genus	Species	Presence	Description	Images
Calanguban	C. alamoi		A non-iguana lizard
Tetrapodophis	T. amplectus		A stem group snake with limbs

Dinosaurs

Dinosaurs of the Crato Formation
Genus	Species	Presence	Notes	Images
?Avialae	?Avialan species		Numerous isolated feathers
Cratoavis	C. cearensis		An enantiornithine
Kaririavis<ref>de Souza Carvalho et al., 2021</ref>	K. mater		An ornithuromorph
?Spinosauroidea	?Spinosaur species		Isolated tooth listed in a book appendix.<ref name="Martill etal 2007" /> It has later been suggested that the lithostratigraphic provenance of this specimen might have been incorrect.<ref name="Caetano et al 2023">Template:Cite journal</ref>
"Ubirajara"	"U. jubatus"		An informally-named compsognathid known from a partial skeleton preserving integument
Sauropoda			Sauropoda footprints.<ref name="Carvalho etal 2021">Template:Cite journal</ref>

Crocodylomorphs

Crocodylomorphs of the Crato Formation
Genus	Species	Presence	Description	Images
Susisuchus	Susisuchus anatoceps<ref name="Salisbury etal 2003">Salisbury et al., 2003. Retrieved 2018-10-06.</ref>
	cf. Susisuchus sp.<ref name="Figueiredo & Kellner, 2009">Figueiredo & Kellner, 2009. Retrieved 2018-10-06.</ref>		Undescribed species

Pterosaurs

Pterosaurs of the Crato Formation
Genus	Species	Presence	Description	Images
Arthurdactylus	A. conandoylei
Aymberedactylus	A. cearensis		A basal member of the Tapejarinae.	Holotype
Brasileodactylus	B. sp.
Lacusovagus	L. magnificens	Nova Olinda Member
Ludodactylus	L. sibbicki		An anhanguerid	Ludodactylus sp.
Tupandactylus	T. imperator T. navigans			Tupandactylus navigans
?Tupuxuara	?T. sp.			Tupuxuara sp.

Flora

Flora of the Crato Formation
Species	Notes
Araucaria cartellei, Brachyphyllum obesum, B. castilhoi, B. insigne, Iara iguassu, Caytoniales sp., Ephedra sp., Araripia florifera, Araucarites vulcanoi, Cariria orbiculiconiformis, Cearania heterophylla, Cratonia cotyledon, Endressinia brasiliana,Klitzchophyllites flabellatus, Novaolindia dubia, Pluricarpellatia peltata, Podozamites lanceolatus, Protananas lucenae, Ruffordia goeppertii, Tomaxellia biforme, Welwitschiaprisca austroamericana, Welwitschiophyllum brasiliense, Welwitschiostrobus murili, Araucariostrobus sp., Frenelopsis sp., Isoetites sp., Lindleycladus sp., Schizoneura sp.	Template:Center

Fungi

Fungi of the Crato Formation
Genus	Species	Presence	Description	Images
Gondwanagaricites	Gondwanagaricites magnificus<ref name=":Heads2017b">Template:Cite journal</ref>
Edaphagaricites	Edaphagaricites conicus<ref name=":GoboAndOliveiraEtAl2025">Template:Cite journal</ref>

Other fossils

• Araripenaeus timidus<ref name="Pinheiro 2014 p4">Pinheiro, 2014, p. 4. Retrieved 2018-10-06.</ref>
• †Cratoalloneura
  • †Cratoalloneura acuminata
  • †Cratoalloneura verdandia
• †Cratoatractocerus
  • †Cratoatractocerus grimaldii
• †Cratoborellia
  • †Cratoborellia gorbi
• †Cratochrysa
  • †Cratochrysa martinsnetoi
  • †Cratochrysa sublapsa
  • †Cratochrysa willmanni
• †Cratocora
  • †Cratocora crassa
• †Cratocordulia
  • †Cratocordulia borschukewitzi
• †Cratocoris
  • †Cratocoris shevchenkoae
• †Cratocorydalopsis
  • †Cratocorydalopsis brasiliensis
• †Cratocossus
  • †Cratocossus magnus
• †Cratodactylus
  • †Cratodactylus ferreirai
  • †Cratodactylus kellneri
• †Cratoelcana
  • †Cratoelcana damianii
  • †Cratoelcana zessini
• †Cratoenigma
  • †Cratoenigma articulata
• †Cratogomphus
  • †Cratogomphus erraticus
• †Cratogryllus
  • †Cratogryllus cigueli
  • †Cratogryllus guimaraesae
  • †Cratogryllus pentagonalis
• †Cratohagenius
  • †Cratohagenius erichweberi
• †Cratohaglopsis
  • †Cratohaglopsis santanaensis
• †Cratohexagenites
  • †Cratohexagenites longicercus
  • †Cratohexagenites minor
• †Cratokalotermes
  • †Cratokalotermes santanensis
• †Cratolindenia
  • †Cratolindenia knuepfae
• †Cratolocustopsis
  • †Cratolocustopsis araripensis
  • †Cratolocustopsis contumax' – type locality for species
  • †Cratolocustopsis cretacea
• †Cratomacer
  • †Cratomacer ephippiger
  • †Cratomacer immersus
• †Cratomastotermes
  • †Cratomastotermes wolfschwenningeri
• †Cratomyia
  • †Cratomyia cretacica
  • †Cratomyia macrorrhyncha
• †Cratonemonyx
  • †Cratonemonyx martinsnetoi
• †Cratonemopteryx
  • †Cratonemopteryx audax
  • †Cratonemopteryx robusta
  • †Cratonemopteryx speciosa
• †Cratonepa
  • †Cratonepa enigmatica
• †Cratonerthra
  • †Cratonerthra corinthiana
  • †Cratonerthra estevezae
• †Cratoneura
  • †Cratoneura dividens
  • †Cratoneura longissima
  • †Cratoneura pulchella
• †Cratonympha
  • †Cratonympha microcelata
• †Cratopelocoris
  • †Cratopelocoris carpinteroi
• †Cratopetalia
  • †Cratopetalia whiteheadi
• †Cratopetalura
  • †Cratopetalura petruleviciusi
  • †Cratopetalura petruleviciusi
• †Cratopsychopsis
  • †Cratopsychopsis maiseyi
• †Cratopteryx
  • †Cratopteryx nemopteroides
  • †Cratopteryx robertosantosi
• †Cratoraricrus
  • †Cratoraricrus oberlii
• †Cratoscalapha
  • †Cratoscalapha electroneura
• †Cratosirex
  • †Cratosirex sennlaubi
• †Cratosisyrops
  • †Cratosisyrops gonzagai
• †Cratosmylus
  • †Cratosmylus magnificus
• †Cratostenophlebia
  • †Cratostenophlebia schwickerti
• †Cratotabanus
  • †Cratotabanus stonemyomorphus
• †Cratotetraspinus
  • †Cratotetraspinus fossorius
• †Cratotipula
  • †Cratotipula latialata
• †Cratovitisma
  • †Cratovitisma oldreadi
• †Cratovoluptia
  • †Cratovoluptia criptoneura
• †Cratozeunerella
  • †Cratozeunerella amedegnatoi
  • †Cratozeunerella godoii
  • †Cratozeunerella neotropica
  • †Cratozeunerella nervosa
  • †Cratozeunerella soaresi
  • †Cratozeunerella titanella

See also

• Araripe Basin
• Botucatu Formation
• Elrhaz Formation
• Itapecuru Formation
• Quiricó Formation

References

Bibliography

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Further reading

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