Lourinhã Formation

Lourinhã Formation Stratigraphic range: Kimmeridgian-Tithonian ~152–146 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Sub-units	Consolação Sub-Basin - Praia da Amoreira-Porto Novo Member, Praia Azul Member, Santa Rita Member Turcifal Sub-Basin - Assenta Member
Underlies
Overlies	& Alcobaça Formations
Thickness	200–1,100 metres (660–3,610 ft)
Lithology
Primary	Sandstone, mudstone, marl
Other	Conglomerate, limestone
Location
Region	Lisbon Region
Country	Portugal
Extent	Lusitanian Basin
Type section
Named for	Lourinhã
Named by	Hill
Year defined	1988

The Lourinhã Formation (Portuguese pronunciation: [loɾiˈɲɐ̃] (listen)) is a fossil rich geological formation in western Portugal, named for the municipality of Lourinhã. The formation is Late Jurassic in age (Kimmeridgian/Tithonian) and is notable for containing a fauna especially similar to that of the Morrison Formation in the United States and a lesser extent to the Tendaguru Formation in Tanzania. There are also similarities to the nearby Villar del Arzobispo Formation. The stratigraphy of the formation and the basin in general is complex and controversial, with the constituent member beds belonging to the formation varying between different authors^[1]

Besides the fossil bones, Lourinhã Formation is well known for the fossil tracks^[2] and fossilized dinosaur eggs.^[3]

The Lourinhã Formation includes several lithostratigraphic units, such as Praia da Amoreira-Porto Novo Members and Praia Azul Member and the Assenta Member.^[4]

Lithology and depositional history[]

Depositional history[]

Location of the Lusitanian basin within the Iberian Peninsula

The Lourinhã Formation is located within the Lusitanian Basin, a mostly onshore North South orientated rift basin within western Portugal, formed during the Opening of the North Atlantic Ocean, with sediment deposition beginning during the Late Triassic-Early Jurassic. It primarily consists of syn-rift near-coastal continental siliciclastic sediments, with several marine intercalations. The primary flow direction was North to South, originating from Galicia and flowing between the Iberian landmass to the east and the now largely submerged Berlengas horst, a North-South oriented ridge, to the west.

Stratigraphy[]

The unit was first formally proposed by Hill in 1988.

The stratigraphy of the Lourinhã Formation is complex and varies between sub-basins with several competing stratigraphic proposals and there is currently no consensus on the matter, one of the most recent stratigraphies,^[1] divides the formation into three members which are from oldest to youngest the Praia da Amoreira-Porto Novo Member, Praia Azul Member, and the Assenta Member.

Praia da Amoreira-Porto Novo Member[]

The Praia da Amoreira-Porto Novo Member is composed of the Priaia de Amoreira Member, which consists of massive mudrock-sand with metre thick sandstone lenses, with massive mudrock with calcrete. The overlying Poto Novo Mb. consists of massive bodies of sandstone, often cross bedded. The environment of deposition is interpreted as a meandering fluvial system, while the Porto Novo Mb is interpreted as a deltaic deposit. It is interpreted to be latest Kimmeridgian in age.

Praia Azul Member[]

The Praia Azul Member, formerly known as the Sobral unit/member is 80 to 130 metres thick and consists of tabular marls and mudstones, with rare sandstones bodies. There are three distinct laterally extensive (>20 km) thin shelly carbonate horizons within this member, indicating brief marine transgressions. South of Santa Cruz primarily consists of sandstone with rare conglomerate. The age is considered to be latest Kimmeridgian to earliest Tithonian.

Assenta Member[]

The Assenta Member is around 300 metres thick and predominantly consists of mudstones with frequent layers of caliche. Near the top of the member several layers of tens of metres thick nodular and marly bioclastic limestones are present, containing marine benthic forams, the nodularity is derived from intense Thalassinoides burrowing. It is predominately late Tithonian in age, with the last few metres probably being earliest Berriasian. The environment of deposition is interpreted as being an upper fluvial-dominated delta to meandering fluvial systems flowing on a paralic plain.

Dinosaurs of the Lourinhã Formation[]

In a 2003 study, an analysis of all Portuguese dinosaurs was published. The study created a cladogram showing the possible relations of all Portuguese dinosaurs, including those at the time known from the Lourinhã Formation.^[5]

Saurichia[]

Theropods[]

Genus	Species	Member	Material	Notes	Images
Abelisauridae indet.[6]	Intermediate[6]		Teeth; ML 966, Ml 327.[6]	Potentially diagnostic abelisaur teeth.[6]
Allosaurus[7][8]	A. europaeus[7]	Porto Novo Member[7]	Two specimens, covering much of the body.[9]	Potentially a synonym of the type species, A. fragilis.
	A. fragilis[8]	Porto Novo Member[7][8]	Two specimens, covering much of the body.[9]	Now thought to represent a distinct species of Allosaurus, A. europaeus.[7]	Allosaurus fragilis
Ceratosaurus[7][10][11]	C. sp.[7][10]	Praia da Amoreira Member[7][10] Amoreira-Porto Novo Member[12]	Four specimens; teeth, a femur.[7][10]	Potentially a synonym of the type species, C. nasicornis. Sometimes referred to as C. sp., giving indication of possible distinctiveness or of being intermediate.[12]	Ceratosaurus
Dendroolithidae[3]	Indeterminant		Fragments of multiple eggs in a clutch, with associated embryonic remains.[3]	Probably eggs of Torvosaurus.[3]
Lusovenator[13]	L. santosi[13]	Praia de Amoreira Member[13]	Two partial postranial skeletons.[13]	Earliest known Carcharodontosaurian from Laurasia.[13]
Lourinhanosaurus[5][14]	L. antunesi[5][14]	Sobral Member[14] Amoreira-Porto Novo Member[12]	Three individuals, one largely complete; over 100 eggs with significant amount of skeletal material.[14]	Has come out in various places in the tree, erroneously said to be a megalosaur,[7] mostly accepted to be a carnosaur, probably allosauroid, or basal coelurosaur. Currently unstable on the tree.[14]	Lourinhanosaurus Embryo
Megalosaurus[6]	M. insignis[6]		Teeth.[6]	Invalid. Teeth belong to various other theropod taxa.[6]
	M. pombali[6]		Teeth.[6]	Invalid. Teeth belong to various other theropod taxa[6]
	M. sp.[6]		Tooth fragment.[6]	Invalid; Dubious.[6]
Richardoestesia[6]	R. aff. gilmorei[6]		Tooth; ML 939[6]	Only definite record of this taxon is from the Late Cretaceous of North America, despite erroneous and referrals from other sites in Portugal. Probably a close relative of Richardoestesia and not an actual representation of the taxon.[6]
Torvosaurus[7][15]	T. gurneyi[15]	Sobral Member[16] Amoreira-Porto Novo Member[12][16] Bombaral Member[16]	Maxilla, Teeth, Femur; Egg clutch and embryos.[3][7][15][16]	Largest known European theropod. Previous known as Portugal populations of the type species, or as T. sp., before description in early 2014.[15]	Skeletal restoration showing the size of T. gurneyi, known remains highlighted.
	T. tanneri[15]	Sobral Member[16] Amoireira-Porto Novo[12][16] Bombaral Member[16]	Maxilla, Teeth, Femur; Probable embryo.[14][15]	Now described as a distinct species of Torvosaurus, T. gurneyi. Sometimes referred to as T. sp. in the past.[15]

Sauropods[]

Genus	Species	Member	Material	Notes	Images
Dinheirosaurus[17][18]	D. lourinhanensis[17][18]	Amoreira-Porta Novo Member[12][17][18]	One specimen. Vertebrae; potentially other parts of the body.[17][18]	Junior synonym of Supersaurus.
Diplodocidae indet.[18]	Intermediate[18]		One Dorsal Vertebra[18]	Regarded by Mannion et al. (2012) as being unique from Dinheirosaurus and possibly indicating another diplodocid in the formation, but being non-diagnostic it doesn't warrant description.[18]
Lourinhasaurus[19]	L. alenquerensis[19]	Sobral Unit (or Sobral Formation) [19]
Lusotitan[20][21]	L. atalaiensis[20][21]		Fragmentary material.[20]	A large brachiosaur, a close relative of Brachiosaurus proper.[20]
Oceanotitan	O. dantasi[22]	Amoreira-Porta Novo Member	scapula, almost all of the pelvis, a complete leg sans the toes, and nine caudals.	A titanosauriform
Supersaurus[23]	S. lourinhanensis[23]	Amoreira-Porta Novo Member[23]	One specimen. Vertebrae; potentially other parts of the body.[23]	Previously Dinheirosaurus. Tschopp et al. (2015) sunk the genus into Supersaurus.[23]
Zby[12]	Z. atlanticus[12]	Amoreira-Porto Novo Member[12]	Holotype: Tooth, cervical neutral arch, forelimb, various other fragments.[12]	No described close relatives from the Morrison Formation or Tendaguru beds; instead allied to other European taxa. Note however teeth from the Tendaguru beds might belong to Turiasauria, as Zby.[12]

Ornithischia[]

Thyreophorans[]

Genus	Species	Member	Material	Notes	Images
Dacentrurus[24]	D. armatus[24]
Deltapodus[25]	D. brodricki[25]		Eleven tracks; Nine pes and two manus prints.[25]	The tracks can be separated into three different morphologies, though all fall within range of the taxon. Association of the pes and manus tracks to the same taxon cannot be directly supported. Preserve various well preserved skin impressions. Largest prints are larger than those from the type horizon. The tracks are individually represented and do not form any sort of trackway, thought one print is associated with giant ornithopod track,[26] potentially representing that the creatures were traveling together or were otherwise going to a similar location. Another is similarly associated with theropod and sauropod prints.[25]
Dracopelta[5]	D. zbyszewskii[5]
Miragaia[24]	M. longicollum[24]	Sobral Unit[24] Amoreira-Porto Novo Member[12]	Holotype, neck, partial skull, forelimbs, ribs. Tentative juvenile specimen assigned to this taxon.[24]	Stegosaur with unusually long neck of 17 cervicals, with more neck vertebrae than most sauropods.[24]
Stegosaurus[27]	S. cf. ungulatus

Ornithopods[]

Genus	Species	Member	Material	Notes	Images
Camptosaurus[28]	Intermediate[28]		Limb material.[28]	Now referred to its own genus, Draconyx, along with some other material.[28]
Draconyx[28]	D. loureiroi[28]	Bombarral Member[28]	Two specimens; holotype, relatively incomplete, and a femur.[28]
Dryosaurus[5]	D. sp.[5]	Sobral Unit			Dryosaurus
Eousdryosaurus[29]	E. nanohallucis[29]	Praia da Amoreira-Porto Novo Formation[29]
Ornithopoda indet.[26]	Intermediate[26]		Single track.[26]	Gigantic track indicating an ornithopod with a hip height of 2.5 meters. No known Jurassic Ornithopod reaches this size; only known evidence for such sizes in this group at the time. Found alongside Deltapodus print.[26]
Phyllodon[5]	P. henkelli.[5]

Synapsids of the Lourinhã Formation[]

Docodonta[]

Dryolestoidea[]

Flora[]

Correlation[]

Early Cretaceous stratigraphy of Iberia

Ma	Age	Paleomap \ Basins		Olanyà								Lusitanian
100	Cenomanian											Caranguejeira
125	Albian		-
			Monte Grande		Escucha		Escucha
			-
	Aptian		-		- Castrillo
					En Gp. -	Morella/			Morella
			-		En Gp. -	Forcall					Upper Bedoulian
	Barremian					Xert	Alacón	Xert		Huérguina
						Artoles				Collado		Papo Seco
				Rúbies	Tera Gp. -	Alacón/Blesa	Blesa	Camarillas
150	Hauterivian				Ur Gp. -			Castellar	Tera Gp. -
							hiatus
	Valanginian				Ur Gp. -				-
					-				- Piedrahita
	Berriasian		-			hiatus
					- Rupelo			Arzobispo	hiatus
					On Gp. -
	Tithonian		Lastres		Tera Gp. -		Higuereles			Tera Gp. -		Lourinhã
									Arzobispo
Legend		Major fossiliferous, oofossiliferous, ichnofossiliferous, coproliferous, minor formation
Sources

See also[]

• Camadas de Alcobaça
• Camadas de Guimarota
• List of fossil sites
• Museu da Lourinhã
• List of dinosaur bearing rock formations

References[]

Bibliography[]

• Antunes, M.T. and Mateus, O. (2003). Dinosaurs of Portugal. C. R. Palevol, 2:77–95
• Mateus, O. (2006). "Late Jurassic dinosaurs from the Morrison Formation, the Lourinhã and Alcobaça Formations (Portugal), and the Tendaguru Beds (Tanzania): a comparison," in Foster, J.R. and Lucas, S. G. R.M., eds., 2006, "Paleontology and Geology of the Upper Jurassic Morrison Formation." New Mexico Museum of Natural History and Science Bulletin 36
• Mateus, O (2007). "Notes and review of the ornithischian dinosaurs of Portugal". Journal of Vertebrate Paleontology. 27: 1–182. doi:10.1080/02724634.2007.10010458.

External links[]

• Antunes & Mateus (2003)
• Mateus (2006)