In the geological timescale, the Berriasian is an age or stage of the Early or Lower Creteceous

Early Cretaceous

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

. It is the oldest or lowest subdivision in the entire Cretaceous

Cretaceous

The Cretaceous , derived from the Latin "creta" , 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 the Jurassic period and is followed by the Paleogene period of the...

. It spanned between 145.5 ± 4.0 Ma and 140.2 ± 3.0 Ma (million years ago). The Berriasian succeeds the Tithonian

Tithonian

In the geologic timescale the Tithonian is the latest age of the Late Jurassic epoch or the uppermost stage of the Upper Jurassic series. It spans the time between 150.8 ± 4 Ma and 145.5 ± 4 Ma...

 (part of the Jurassic

Jurassic

The Jurassic is a geologic period and system that extends from about Mya to  Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...

) and precedes the Valanginian

Valanginian

In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 140.2 ± 3.0 Ma and 136.4 ± 2.0 Ma...

.

Stratigraphic definitions

The Berriasian stage was introduced in scientific literature by Henri Coquand in 1869. It is named after the village of Berrias in the Ardèche

Ardèche

Ardèche is a department in south-central France named after the Ardèche River.- History :The area has been inhabited by humans at least since the Upper Paleolithic, as attested by the famous cave paintings at Chauvet Pont d'Arc. The plateau of the Ardeche River has extensive standing stones ,...

 region of France

France

The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

. The largely non-marine English Purbeck Formation is of Berriasian age and in the past the names Purbeck and Wealden were also used to address rocks of the lowest Cretaceous.

The base of the Berriasian (also the base of the Cretaceous system) has traditionally been placed at the first appearance of fossils of the ammonite

Ammonite

Ammonite, as a zoological or paleontological term, refers to any member of the Ammonoidea an extinct subclass within the Molluscan class Cephalopoda which are more closely related to living coleoids Ammonite, as a zoological or paleontological term, refers to any member of the Ammonoidea an extinct...

 species Berriasella jacobi

Berriasella

Berriasella is a discoidal evolute perisphinctacean ammonite, and type genus for the neocomitid subfamily Berriasellinae. Its ribbing is distinct, consisting of both simple and bifurcated ribs that extend from the umbilical seam across the venter; its whorl section generally compressed, the venter...

. A global reference profile (a GSSP) for the Berriasian is under active consideration by the Cretaceous International Subcommission (ISCS) of IUGS. A range of contender GSSP localities are currently being studied by the ISCS's Berriasian Working Group. Several markers are being employed to refine correlations and to work towards definition of a stage base. These include calcareous nannofossils, such as Nannoconus steinmannii, calpionellids, ammonites, palynological datums and magnetostratigraphy, notably the base of chron m18r.

In the Tethyan Realm

Tethys Ocean

The Tethys Ocean was an ocean that existed between the continents of Gondwana and Laurasia during the Mesozoic era before the opening of the Indian Ocean.-Modern theory:...

, the Berriasian consists four ammonite biozone

Biozone

Biostratigraphic units or Biozones are intervals of geological strata that are defined on the basis of their characteristic fossil taxa....

s, from top to bottom:

• Thurmanniceras otopeta
• Subthurmannia boissieri
• Subthurmannia occitanica
• Berriasella jacobi

The top of the Berriasian stage (the base of the Valanginian) is at the first appearance of calpionellid species Calpionellites darderi in the stratigraphic column. This is just a little below the first appearance of ammonite species Thurmanniceras pertransiens.

Birds

Birds of the Berriasian
Taxa	Presence	Location	Description	Images
Eurolimnornis Eurolimnornis Eurolimnornis is the name given to a monotypic genus of fossil bird from the Early Cretaceous. E. corneti probably was a primitive, but essentially modern bird and may indeed be an early neognathe ancestral to the grebes, although the alternative theories that it was a theropod or pterosaur or a...
Gallornis
Palaeocursornis Palaeocursornis Palaeocursornis is a monotypic genus of prehistoric bird. The species P. corneti, described in 1984, was initially assumed to be a flightless paleognathe, possibly a ratite, but it may actually be more primitive and not even a neornithine but an ornithuromorph bird or indeed not a bird at all...
Wyleyia Wyleyia Wyleyia is a prehistoric bird genus with a single species, Wyleyia valdensis, known from the Early Cretaceous of England. Even this is only known from a single damaged right humerus. It has been named to honor J. F. Wyley, who found the specimen in the Weald Clay deposits of Henfield in Sussex...

Crocodylomorphs

Crocodylomorphs of the Berriasian
Taxa	Presence	Location	Description	Images
Dakosaurus andiniensis
Geosaurus Geosaurus Geosaurus is an extinct genus of marine crocodyliform within the family Metriorhynchidae that lived during the Late Jurassic to the Early Cretaceous. Geosaurus was a carnivore that spent much, if not all, its life out at sea...
Goniopholis Goniopholis Goniopholis is an extinct genus of crocodyliform that lived in North America, Europe and Asia during the Late Jurassic and Early Cretaceous. Being semi-aquatic it is very similar to modern crocodiles...
Lisboasaurus Lisboasaurus Lisboasaurus is a small genus of Mesozoic crocodylomorph that lived in fresh water. It is known from fossilized tooth and jaw fragments of Late Jurassic and Early Cretaceous age. Two species have been described. In the past Lisboasaurus has been interpreted as a Mid Jurassic avialan, troodontid,...
Steneosaurus Steneosaurus Steneosaurus is an extinct genus of teleosaurid crocodyliform from the Early Jurassic to Early Cretaceous . Fossil specimens have been found in England, France, Germany, Switzerland and Morocco.-Species:...

Mammalia

Mammals of the Berriasian
Taxa	Presence	Location	Description	Images
Albionbaatar Albionbaatar Albionbaatar is an extinct mammal from the Lower Cretaceous of England. It was a member of the also extinct order Multituberculata and shared the world with the much larger dinosaurs. It is in the suborder "Plagiaulacida", family Albionbaataridae. The genus Albionbaatar was named by...		Durlston Bay, Dorset, England
Bolodon Bolodon Bolodon is a genus of extinct mammal from the Lower Cretaceous of Europe, and possibly the Upper Jurassic of North America. It was a member of the extinct order of Multituberculata and lived at the same time as dinosaurs. It is placed in the suborder Plagiaulacida and family Plagiaulacidae.The...		Durlston Bay, Dorset, England; Spain
Ecprepaulax Ecprepaulax Ecprepaulax is a Lower Cretaceous mammal from Portugal. It was a member of the also extinct order Multituberculata and shared the world with dinosaurs. It lies within the suborder "Plagiaulacida" and family Pinheirodontidae....		Portugal
Gerhardodon Gerhardodon Gerhardodon is an extinct genus of mammal from the Lower Cretaceous of southern England. It was a member of the also extinct order of Multituberculata, and lived with such dinosaurs as Iguanodon. It lies within the suborder "Plagiaulacida" and family Pinheirodontidae.The genus Gerhardodon was...		Durlston Bay, Dorset, England
Iberodon Iberodon Iberodon is a small, extinct mammal of the Lower Cretaceous from Portugal. It was a member of the also extinct order Multituberculata, and led its obscure and plant-eating existence in the company of dinosaurs. It lies within the suborder "Plagiaulacida" and family Pinheirodontidae.The genus...		Portugal

†Ornithischians

Ornithischians of the Berriasian
Taxa	Presence	Location	Description	Images
Echinodon Echinodon Echinodon meaning "hedgehog tooth" in reference to the spines on its teeth , occasionally known as Saurechinodon, is a genus of small European dinosaur of the early Cretaceous Period , 140 million years ago.-Discovery and species:The type specimen was discovered by Samuel Beckles in the Purbeck...		Swanage Swanage Swanage is a coastal town and civil parish in the south east of Dorset, England. It is situated at the eastern end of the Isle of Purbeck, approximately 10 km south of Poole and 40 km east of Dorchester. The parish has a population of 10,124 . Nearby are Ballard Down and Old Harry Rocks,... , England	A bipedal herbivore, it was around 0.6 meters (2 ft) long. Unlike most ornithischians, Echinodon had one or two caniniform teeth in each maxilla.
Hylaeosaurus Hylaeosaurus Hylaeosaurus is the most obscure of the three animals used by Sir Richard Owen to first define the new group Dinosauria, in 1842. The original specimen, recovered by Gideon Mantell from the Tilgate Forest in the south of England in 1832, now resides in the Natural History Museum of London, where...
Owenodon Owenodon Owenodon is a genus of iguanodontian dinosaur known from a partial lower jaw discovered in Early Cretaceous-age rocks of Durlston Bay, Dorset, United Kingdom. The specimen, NHM R2998, comes from the Purbeck Limestone, dating to the middle Berriasian stage...
Paranthodon Paranthodon Paranthodon was a dinosaur from the early Cretaceous. It lived in what is now South Africa. It is classified as a stegosaur. It has a long and confusing history. The type species, Paranthodon africanus, comes from a partial skull first described as Palaeoscincus africanus in 1912...		Kirkwood Formation Kirkwood Formation The Kirkwood Formation is a geological formation in Eastern Cape and Western Cape provinces, South Africa whose strata date back to the Early Cretaceous... , Cape Province, South Africa	A 4 meters long, 1.8 meters high stegosaurid with a skull similar to Kentrosaurus Kentrosaurus Kentrosaurus is a genus of stegosaurid dinosaur from the Late Jurassic of Tanzania. Its fossils have been found only in the Tendaguru Formation of Tanzania, dated to the Kimmeridgian stage, between about 155.7 ± 4 Ma and 150.8 ± 4 Ma . Apparently, all finds belong to one species, K...
Valdosaurus Valdosaurus Valdosaurus is a genus of bipedal herbivorous iguanodont ornithopod dinosaur found on the Isle of Wight and elsewhere in England. It lived during the Early Cretaceous.-Discovery and naming:...		Isle of Wight, England; Niger, Africa	A dryosaurid

†Pterosaurs

Pterosaurs of the Berriasian
Taxa	Presence	Location	Description	Images
Plataleorhynchus Plataleorhynchus Plataleorhynchus was a genus of ctenochasmatid pterodactyloid pterosaur from the Tithonian-Berriasian-age Upper Jurassic or Lower Cretaceous Purbeck Limestone of Dorset, England....

†Sauropods

Sauropods Sauropoda Sauropoda , or the sauropods , are an infraorder of saurischian dinosaurs. They had long necks, long tails, small heads , and thick, pillar-like legs. They are notable for the enormous sizes attained by some species, and the group includes the largest animals to have ever lived on land...  of the Berriasian
Taxa	Presence	Location	Description	Images
Algoasaurus Algoasaurus Algoasaurus is a genus of sauropod dinosaur from the Tithonian-early Valanginian-age Late Jurassic-Early Cretaceous Upper Kirkwood Formation of Cape Province, South Africa. It was a neosauropod; although it has often been assigned to the Titanosauridae, there is no evidence for this, and recent...
Galveosaurus Galveosaurus Galveosaurus is an extinct genus of dinosaur from the Late Jurassic to Early Cretaceous periods. Its fossils were found in Galve, Spain, hence its generic name, "Galve lizard". The specific name honours the discoverer, José María Herrero....
Turiasaurus Turiasaurus Turiasaurus is a genus of sauropod dinosaur from the Jurassic-Cretaceous boundary...
Xenoposeidon Xenoposeidon Xenoposeidon is a genus of sauropod dinosaur from the Early Cretaceous of England, living about 140 million years ago. It is known from a single partial vertebra with unusual features, unlike those of other sauropods...
Pelorosaurus

†Thalattosuchia

†Thalattosuchians of the Berriasian
Taxa	Presence	Location	Description	Images
Machimosaurus Machimosaurus Machimosaurus is an extinct genus of teleosaurid crocodyliform from the Late Jurassic and Early Cretaceous . The type species, Machimosaurus hugii, was found in France. Other fossils have been found in Austria, England, Germany, Portugal and Switzerland...	From Kimmeridgian Kimmeridgian In the geologic timescale, the Kimmeridgian is an age or stage in the Late or Upper Jurassic epoch or series. It spans the time between 155.7 ± 4 Ma and 150.8 ± 4 Ma . The Kimmeridgian follows the Oxfordian and precedes the Tithonian....  to Valanginian Valanginian In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 140.2 ± 3.0 Ma and 136.4 ± 2.0 Ma...	Austria, England, Germany, Portugal and Switzerland
Steneosaurus Steneosaurus Steneosaurus is an extinct genus of teleosaurid crocodyliform from the Early Jurassic to Early Cretaceous . Fossil specimens have been found in England, France, Germany, Switzerland and Morocco.-Species:...	Attested since Toarcian Toarcian The Toarcian is, in the ICS' geologic timescale, an age or stage in the Early or Lower Jurassic. It spans the time between 183.0 Ma and 175.6 Ma...	England, France, Germany, Switzerland and Morocco

†Theropods (non-avian)

†Non-avian Paraphyly A group of taxa is said to be paraphyletic if the group consists of all the descendants of a hypothetical closest common ancestor minus one or more monophyletic groups of descendants...  theropods Theropoda Theropoda is both a suborder of bipedal saurischian dinosaurs, and a clade consisting of that suborder and its descendants . Dinosaurs belonging to the suborder theropoda were primarily carnivorous, although a number of theropod groups evolved herbivory, omnivory, and insectivory...  of the Berriasian
Taxa	Presence	Location	Description	Images
Dromaeosauroides Dromaeosauroides Dromaeosauroides is a genus of dromaeosaurid theropod dinosaur from the Early Cretaceous of Denmark.In the southwest of the island of Bornholm, layers of the Early Cretaceous Jydegaard Formation surface, dating to the late Berriasian age, about 140 million years ago and consisting of marine...
Embasaurus Embasaurus Embasaurus is a genus of theropod dinosaur from the Early Cretaceous period. Fossils have been found in Kazakhstan in central Asia. As it is known only from two fragmentary vertebrae, Embasaurus is considered a nomen dubium, taxonomic placeholder lacking sufficient evidence to establish the...
Nuthetes Nuthetes Nuthetes is the name given to a dubious, possibly dromaeosaurid, genus of theropod dinosaur, known only from fossil teeth and jaw fragments found in rocks of the middle Berriasian age in the Cherty Freshwater Member of the Lulworth Formation in England...

External links

• GeoWhen Database - Berriasian
• Jurassic-Cretaceous timescale, at the website of the subcommission for stratigraphic information of the ICS
• Stratigraphic chart of the Lower Cretaceous, at the website of Norges Network of offshore records of geology and stratigraphy