Crato Formation



Crato is somewhat like the Santana Formation in that they are both located in Brazil’s Araripe Plateau.

Both of these are marine formations made up of limestone and both show a side of Brazil when an arm of the ancient Atlantic Ocean flooded the land.

Earlier, the Crato Formation was known as just the Crato Member and referred to as the lowest section of the Santana Formation. Now we know that it was a separate part of the Araripe region, somewhere around ten or so million years older.

The Setting

Many of the Crato animals are known from exquisite soft tissue remains. This especially goes for the insect specimens from the Crato, of which beautiful wing impressions are known.

Some of the invertebrate life includes antlions, spiders, scorpions, dragonflies, water bugs and centipedes. The invertebrate life of any area is important to get a clear idea of the food web of that region.
Many rock formations in and around the former Gondwanan supercontinent are not so well-known and most do not preserve a good record of life at the time. The Crato and Santana Formations both break this norm quite easily.

They show us a wonderful picture of what life in Gondwana was like in the Early Cretaceous Aptian-Albian boundary. There was also a diversification of plant life, especially of angiosperms or flowering plants.

Among these, are genera of ancestral water lilies, among the oldest flowering plants of all time. The fact that this existed alongside so many insects, shows us that invertebrates and flora were beginning to evolve the relationships that we see between them to this day.

Also there are ancestors of the strange Welwitschia plant. These are gymnosperms, a much more ancient type of plant that also includes conifers and ferns. Welwitschia grows today in Angola and Namibia, in the Namib Desert.

It spends its life growing horizontally as opposed to vertically, with massive leaves spread around a tiny stem and root system in all directions. Another gymnosperm here is the fern genus Ruffordia, a very widespread genus.

Lindleycladus is an araucaria, another gymnosperm.

Numerous fish are also known from Crato, most of them bony. Species of Cladocyclus are known, just as in the Santana Formation somewhat later. Smaller fish genera are also known here.


A well-known genus of crocodylomorph is known from this formation. This stem-crocodile is the small, basal genus Susisuchus. Two species are known, with Susisuchus anatoceps being the type species. It was among the very earliest ancestors of eusuchians or true crocodiles known, and good soft tissue remains have been found in the Crato.

The holotype of S.anatoceps is currently the best specimen. It shows even its armored scutes, which look less like those of more basal genera and more like what is known from its close relative Isisfordia from Australia. The latter is even closer to the Eusuchia than Susisuchus is.

Susisuchus was a very small animal, at around a meter in length. It probably fed on fish and other small animals.


Crato is best known for its pterosaurs though, and just like Santana there was a great diversity of omivorous and herbivorous tapejarids.

The most famous of all tapejarids is Tupandactylus navigans, which is just one species in the genus. Tupandactylus is typical for its kind, with its large wingspan of 5 meters and an immense head perched on a small body. T. navigans is known for starring in the 1999 BBC miniseries Walking with Dinosaurs but under the name of Tapejara.

At the time the show was created, it was thought to have been a species of the genus Tapejara. This species was known for its very tall, somewhat pointed soft tissue crest that had the profile view of a large cone.

On the show the cone was ridged, but possibly for the sake of artistic license. T. navigans was actually a very small member of its genus.

The real giant was T. imperator, the type species of the genus. It also shows signs of having furry pycnofibers close to the keratinous covering of its beak. The beaks of pterosaurs themselves covered a smaller part of their jaws, not the whole of the jaws.

The crest was supported by the bones extending from the skull. In fact, most of the pterosaurs here were rather large.

One of the main predators in the region must have been Lacusovagus, a chaoyangopterid. This group was very close to azhdarchids, and probably lived the same lifestyle as a big terrestrial stalker.

A piscivore from this formation was the pteranodontoid genus Ludodactylus. Ludodactylus sibbicki means ‘Sibbick’s toy finger’, with the species name honoring paleontographer John Sibbick.

The genus name means ‘toy finger’ after the fact that the genus resembled many toy pterosaurs which have both bony crests and teeth. Many pterodactyloids before didn’t have teeth and a bony crest, while in recent years there have been plenty of toothed pterosaurs with keratin crests.

The holotype is a skull with a yucca leaf caught in its throat. So far non-avialan dinosaurs are rare in the Crato.