| Lourinhã Formation | |
| Type: | Geological formation |
| Age: | late Kimmeridgian-earliest Berriasian ~ |
| Period: | Tithonian |
| Prilithology: | Sandstone, mudstone, marl |
| Otherlithology: | Conglomerate, limestone |
| Namedfor: | Lourinhã |
| Namedby: | Hill |
| Year Ts: | 1988 |
| Region: | Lisbon Region |
| Country: | Portugal |
| Coordinates: | 39.23°N -9.32°W |
| Subunits: |
|
| Underlies: | Porto da Calada Formation |
| Overlies: | Consolação & Alcobaça Formations |
| Thickness: | NaNm (-2,147,483,648feet) |
| Extent: | Lusitanian Basin |
The Lourinhã Formation (pronounced as /pt/) is a fossil rich geological formation in western Portugal, named for the municipality of Lourinhã. The formation is mostly Late Jurassic in age (Kimmeridgian/Tithonian), with the top of the formation extending into the earliest Cretaceous (Berriasian). It 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 and Alcobaça 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, Praia Azul Member, the Santa Rita Member, and the Assenta Member.[4]
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.
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, 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.
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, and overlies the Consolacao Unit at the top of the Aulacostephanus eudoxus ammonite zone.
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, correlated to the ammonite zones of Hybonoticeras beckeri and Hybonoticeras hybonotum.
The Santa Rita Member in the Consolação sub-basin and its lateral equivalent in the Turcifal Basin 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, with the top of the formation roughly correlative with the base of the magnetochron M18n. (~144.7 Ma) The environment of deposition is interpreted as being an upper fluvial-dominated delta to meandering fluvial systems flowing on a paralic plain.
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]
| Genus | Species | Member | Material | Notes | Images |
|---|---|---|---|---|---|
| Camptosaurus | Intermediate | Limb material | Now referred to its own genus, Draconyx, along with some other material. | ||
| Draconyx[6] | D. loureiroi | Praia Azul Member[7] | One partial skeleton | ||
| Dryosauridae indet.[8] | Indeterminate | Praia Azul Member | Appendicular, axial, and cranial elements | ||
| Ankylopollexia indet. | Indeterminate |
| Appendicular, axial, and cranial elements | ||
| Dryosaurus | D. sp. | Praia Azul Member | |||
| Eousdryosaurus[9] | E. nanohallucis | Praia da Amoreira-Porto Novo Formation | A partial postcranial skeleton. | ||
| Hesperonyx[10] | H. martinhotomasorum | Porto Novo Member | Bones from the fore- and hindlimbs | A dryomorphan iguanodontian with uncertain affinities | |
| Ornithopoda indet. | Intermediate | A single track | 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.[11] | ||
| Phyllodon | P. henkelli. | Two teeth | |||
| Genus | Species | Member | Material | Notes | Images |
|---|---|---|---|---|---|
| Dacentrurus[12] | D. armatus | A stegosaurid | |||
| Deltapodus[13] | D. brodricki | Eleven tracks; Nine pes and two manus prints. | The tracks can be separated into three different morphologies, though all fall within range of the Ornithopodsociation 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, 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. | ||
| Dracopelta | D. zbyszewskii | Assenta Member | An ankylosaur. | ||
| Miragaia[14] | M. longicollum |
| Holotype, neck, partial skull, forelimbs, ribs. Tentative juvenile specimen assigned to this taxon. | Stegosaur with unusually long neck of 17 cervicals, with more neck vertebrae than most sauropods. Probably a junior synonym of Dacentrurus.[16] [17] | |
| Genus | Species | Member | Material | Notes | Images |
|---|---|---|---|---|---|
| Trimucrodon | T. cuneatus | Amoreira-Porto Novo Member | 3 isolated teeth. | ||
| Alocodon | A. kuehnei | ||||
| Genus | Species | Member | Material | Notes | Images | |
|---|---|---|---|---|---|---|
| Dinheirosaurus[18] | D. lourinhanensis | Praia da Amoreira-Porta Novo Member | One specimen. Vertebrae; potentially other parts of the body. | A diplodocid. Tschopp et al. (2015) sunk the genus into Supersaurus. | Rowspan = 100 | |
| Diplodocidae indet.[19] | Intermediate | One Dorsal Vertebra | 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. | |||
| Lourinhasaurus[20] | L. alenquerensis | Praia Azul Member | A partial postcranial skeleton. | Possibly a Camarasaurid Macronarian. | ||
| Lusotitan[21] | L. atalaiensis[22] | Praia Azul Member | Fragmentary material. | A large brachiosaur, a close relative of Brachiosaurus proper. | ||
| Oceanotitan | O. dantasi[23] | Praia da Amoreira-Porta Novo Member | scapula, almost all of the pelvis, a complete leg sans the toes, and nine caudals. | A titanosauriform | ||
| Zby | Z. atlanticus[24] | Amoreira-Porto Novo Member | Holotype: Tooth, cervical neutral arch, forelimb, various other fragments. | A turiasaur. | ||
| Genus | Species | Member | Material | Notes | Images |
|---|---|---|---|---|---|
| Abelisauridae indet. | Intermediate | Praia da Amoreira-Porto Novo Member | Teeth; ML 966, Ml 327. | Potentially diagnostic abelisaur teeth. | |
| Allosaurus[25] [26] | A. europaeus | Praia Azul Member | Two specimens, covering much of the body.[27] | Only European species of Allosaurus. | |
| A. fragilis | Praia Azul Member | Two specimens, covering much of the body. | Now thought to represent a specimen of A. europaeus. | ||
| Ceratosaurus[28] [29] | C. sp. | Praia da Amoreira-Porto Novo Member | Four specimens; teeth, a femur. | Potentially a synonym of the type species, C. nasicornis. Sometimes referred to as C. sp., giving indication of possible distinctiveness or of being intermediate. | |
| Dendroolithidae | Indeterminant | Fragments of multiple eggs in a clutch, with associated embryonic remains. | Probably eggs of Torvosaurus. | ||
| Lusovenator[30] | L. santosi |
| Two partial postcranial skeletons. | Earliest known Carcharodontosaurian from Laurasia. | |
| Lourinhanosaurus[31] | L. antunesi | Praia Azul Member | Three individuals, one largely complete; over 100 eggs with significant amount of skeletal material. | Has come out in various places in the tree, erroneously said to be a megalosaur, mostly accepted to be a carnosaur, probably allosauroid, or basal coelurosaur. Currently unstable on the tree. | |
| Megalosaurus[32] | M. insignis | Teeth. | Invalid. Teeth belong to various other theropod taxa. | ||
| M. pombali | Teeth. | Invalid. Teeth belong to various other theropod taxa | |||
| M. sp. | Tooth fragment. | Invalid; Dubious. | |||
| Richardoestesia | R. aff. gilmorei | Tooth; ML 939 | 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. | ||
| Torvosaurus[33] | T. gurneyi |
| Maxilla, Teeth, Femur; Egg clutch and embryos.[35] | Largest known European theropod. Previous known as Portugal populations of the type species, or as T. sp., before description in early 2014. | |
| T. tanneri | Praia da Amoireira-Porto Novo | Maxilla, Teeth, Femur; Probable embryo. | Now described as a distinct species of Torvosaurus, T. gurneyi. Sometimes referred to as T. sp. in the past. | ||
| Genus | Species | Member | Material | Notes | Images | |
|---|---|---|---|---|---|---|
| Dsungaripteroidea indet.[36] | Indeterminate | Proximal right femur | ||||
| Rhamphorhynchidae[37] | Indeterminate | Tooth | ||||
| Lusognathus | L. almadrava | Skull and cervical vertebrae | Ctenochasmatid | |||
| Pteraichnus[38] | Partial tracks |
| Genus | Species | Member | Material | Notes |
|---|---|---|---|---|
| Nanolestes | Nanolestes drescherae | Right lower molar. | Amphitheriidae
| |
| Guimarotodus | Guimarotodus inflatus | Right mandible. | Dryolestidae
| |
| Krebsotherium | Krebsotherium lusitanicum | Left mandible. | Dryolestidae
| |
| Drescheratherium | Drescheratherium acutum | Upper jaw. | Paurodontidae
| |
| Genus | Species | Member | Material | Notes | |
|---|---|---|---|---|---|
| Celtedens | Indeterminate | Porto Novo/Praia da Amoreira, Praia Azul | Frontal bones,[39] along with other parts of the skull and limbs | An albanerpetontid. | |
| Urodela | Indeterminate | Atlas vertebra | A salamander, suggested to belong to Scapherpetontidae. | ||
| "Discoglossidae" | Indeterminate | Partial left humerus | A primitive frog |
| Genus | Species | Member | Material | Notes | |
|---|---|---|---|---|---|
| Ophiussasuchus | O. paimogonectes | Praia Azul Member | Partial skull | Goniopholidid | |
| Goniopholididae | Indeterminate | Teeth[40] and partial skeleton.[41] | An aquatic neosuchian | ||
| Tooth | |||||
| Lusitanisuchus | Teeth, and partial skull and jaw fragments | A mesoeucrocodylian of uncertain placement | |||
| Atoposauridae | Teeth | ||||
| Teeth | Distinct from Lusitanisuchus |
| Genus | Species | Member | Material | Notes |
|---|---|---|---|---|
| Hybodus[42] | H. cf. reticulatus | Teeth | A hybodontid shark | |
| Pycnodontiformes | Indeterminate | |||
| Lepidotes sensu lato | A ginglymodian | |||
| Caturus | An amiiform |
| Genus | Species | Member | Material | Notes | Images |
|---|---|---|---|---|---|
| Pterophyllum | P. mondeguensis[43] | Bennettitales leaf | |||
| Otozamites | Bennettitales leaf | ||||
| Cupressinocladus | Conifer leaves | ||||
| Protocupressinoxylon[44] | Conifer wood | ||||
| Prototaxoxylon | |||||
| Classopollis | Pollen of Cheirolepidiaceae conifers | ||||