Bartoon: Parque de Dinossauros da Lourinhã

- Vão começar muito em breve as obras do Parque Jurássico da Lourinhã...

... que será o maior parque de dinossauros ao ar livre na Europa.

- Julgo que não haverá dificuldades em povoá-lo. 

Nas Autarquias, no Parlamento... o que não falta aí é bicharada jurássica.

Bartoon de 23.6.2013, por Luís Afonso.

Osteologia do saurópode Lusotitan atalaiensis

O saurópode português Lusotitan atalaiensis é alvo de uma nova re-descrição anatómica, publicada no Zoological Journal of the Linnean Society. 

Mannion, P. D., Upchurch P., Barnes R. N., & Mateus O. (2013).  Osteology of the Late Jurassic Portuguese sauropod dinosaur Lusotitan atalaiensis (Macronaria) and the evolutionary history of basal titanosauriforms. Zoological Journal of the Linnean Society. 1-109. LINK



Abstract Titanosauriforms represent a diverse and globally distributed clade of neosauropod dinosaurs, but their inter-relationships remain poorly understood. Here we redescribe Lusotitan atalaiensis from the Late Jurassic Lourinhã Formation of Portugal, a taxon previously referred to Brachiosaurus. The lectotype includes cervical, dorsal, and caudal vertebrae, and elements from the forelimb, hindlimb, and pelvic girdle. Lusotitan is a valid taxon and can be diagnosed by six autapomorphies, including the presence of elongate postzygapophyses that project well beyond the posterior margin of the neural arch in anterior-to-middle caudal vertebrae. A new phylogenetic analysis, focused on elucidating the evolutionary relationships of basal titanosauriforms, is presented, comprising 63 taxa scored for 279 characters. Many of these characters are heavily revised or novel to our study, and a number of ingroup taxa have never previously been incorporated into a phylogenetic analysis. We treated quantitative characters as discrete and continuous data in two parallel analyses, and explored the effect of implied weighting. Although we recovered monophyletic brachiosaurid and somphospondylan sister clades within Titanosauriformes, their compositions were affected by alternative treatments of quantitative data and, especially, by the weighting of such data. This suggests that the treatment of quantitative data is important and the wrong decisions might lead to incorrect tree topologies. In particular, the diversity of Titanosauria was greatly increased by the use of implied weights. Our results support the generic separation of the contemporaneous taxa Brachiosaurus, Giraffatitan, and Lusotitan, with the latter recovered as either a brachiosaurid or the sister taxon to Titanosauriformes. 

Vértebras caudais de Lusotitan atalaiensis 

Although Janenschia was recovered as a basal macronarian, outside Titanosauria, the sympatric Australodocus provides body fossil evidence for the pre-Cretaceous origin of titanosaurs. We recovered evidence for a sauropod with close affinities to the Chinese taxon Mamenchisaurus in the Late Jurassic Tendaguru beds of Africa, and present new information demonstrating the wider distribution of caudal pneumaticity within Titanosauria. The earliest known titanosauriform body fossils are from the late Oxfordian (Late Jurassic), although trackway evidence indicates a Middle Jurassic origin. Diversity increased throughout the Late Jurassic, and titanosauriforms did not undergo a severe extinction across the Jurassic/Cretaceous boundary, in contrast to diplodocids and non-neosauropods. Titanosauriform diversity increased in the Barremian and Aptian–Albian as a result of radiations of derived somphospondylans and lithostrotians, respectively, but there was a severe drop (up to 40%) in species numbers at, or near, the Albian/Cenomanian boundary, representing a faunal turnover whereby basal titanosauriforms were replaced by derived titanosaurs, although this transition occurred in a spatiotemporally staggered fashion.

Embriões de dinossauro, de Paimogo, Lourinhã

O Mesozóico de Portugal tem mostrado uma diversidade de abundância de fósseis de dinossauros e outros vertebrados. Ossos, ovos, embriões, pegadas, pele, coprólitos, e gastrólitos são algumas das descobertas que enriquecem lista de achados na Bacia Lusitânica, sobretudo do Jurássico Superior da Formação da Lourinhã.
Várias espécies únicas sublinham a importância, que acompanhadas com a ocorrência de ovos, ninhos e embriões, como no caso do terópode Lourinhanosaurus antunesi, permitem compreender mais sobre a reprodução, comportamento, crescimento, metabolismo e evolução dos dinossauros.

Parte deste trabalho foi apresentado no congresso Society of Vertebrate Paleontology Meeting, e o resumo é o seguinte:

Referência:

Mateus, O., Carrano, M.T., Taquet P. (2012). Osteology of the embryonic theropods from the Late Jurassic of Paimogo, Portugal. Journal of Vertebrate Paleontology, Program and Abstracts, 2012, p.137. ISSN 1937-2809. 137.

PDF aqui

Resumo / Abstract:

Osso de embrião

Among the more than one dozen dinosaur egg- and eggshell-bearing localities in the Upper Jurassic Lourinhã Formation of Portugal (upper Kimmeridgian–Tithonian), the nest from Paimogo was the first to be found and remains the largest and most significant. Located within the Amoreira-Porto Novo Member (uppermost Kimmeridgian), this nest has yielded about 300 embryonic bones and bone fragments identified as belonging to a theropod dinosaur.

The Paimogo nest comprised about 100 eggs (or eggshell concentrations that represented individual eggs), but much of the nest had been eroded, indicating that an even greater number of eggs would have been present originally. There is no clear nest structure, but eggs are more highly concentrated in the center, along with the majority of embryonic bones (suggesting a more advanced ontogenetic stage). All the eggs were crushed, but despite this compression, some eggs are complete and retain embryonic bones inside.

The embryonic anatomy is has been favorable compared to the holotype of Lourinhanosaurus antunesi Mateus 1998 from the same stratum and region. However, most Lourinhanosaurus autapomorphies are in the pelvis and vertebral laminae, rarely preserved in the embryos, making their positive identification more difficult. A single autapomorphy is present in both subadult and embryo: a medial condyle of the tibia that is half the transverse width of the fibular condyle. Other contemporary theropods differ from the embryos in specific details: the embryonic maxilla lacks an antorbital fenestra (present in Allosaurus), the ilium lacks a vertical ridge (present in Aviatyrannis), and the tibial cnemial crest is short (unlike Ceratosaurus). One other nest with embryo from Lourinhã area, in Porto das Barcas has been provisionally ascribed to Torvosaurus. This embryos specimen are much larger in size, and the eggshell structure is entirely different. If such ascription of Porto das Barcas embryos is correct, then Paimogo embryos cannot be Torvosaurus.
In general, the embryos are morphological miniatures of the adults, fully equipped for predation of small prey, and thus may have been precocial (i.e. relatively mature and mobile from the moment of birth or hatching). The teeth have large denticles on the distal carina only and bear some resemblance to those of more derived theropods, suggesting a role for pedomorphosis in theropod evolution.

Idade dos dinossauros e outros vertebrados do Jurássico Superior de Portugal

O Jurássico Superior (163.5 a 145.0 Milhões de anos) é claramente o período de tempo sobre o qual temos mais vestígios de dinossauros em Portugal. Mas esta época representa 17.5 milhões de anos pelo é importante melhorar a resolução destas idades e compreender a correlação estratigráfica dos achados. Esse trabalho, desenvolvido por Vasco Ribeiro e por mim, foi apresentado no congresso Society of Vertebrate Paleontology Meeting.

Este é o resumo:

Chronology of the Late Jurassic dinosaur faunas, and other reptilian faunas, from Portugal

The chronostratigraphy of Late Jurassic vertebrates from Portugal, including those from the Lourinhã Formation, which is known for its rich vertebrate fauna, is poorly understood due to the continental nature of the sediments and the diachrony of the lithostratigraphic units. 

Recent results using Sr87/86 isotopes confirmed the position of the Kimmeridgian-Tithonian boundary (150.8 Ma) in the Lusitanian Basin central sector. This boundary, within a marly layer representative of the more southernly limestone Farta Pão Formation, lies within the siliciclastic Lourinhã Formation and is assumed to be the transgressive upper Kimmeridgian -lower Tithonian event. The most productive vertebrate-bearing Upper Jurassic formations in Portugal are: the Alcobaça Formation, Lourinhã Formation (divided into the Amoreira-Porto Novo, Sobral, Bombarral, and Freixial (pars) members), and the Porto da Calada Formation.

The chronological range (given by biostratigraphy, eustatic curves, general regional context, and calibrated by strontium isotope curves) for important Portuguese specimens of chelonians, pterosaurs, dinosaurs, crocodylomorphs, and other reptilians is as follows: 

Early (to late?) Kimmeridgian (Alcobaça Beds Formation): Theriosuchus guimarotae, Machimosaurus hugii, Goniopholis baryglyphaeus, Lusitanisuchus mitrocostatus, Phyllodon henkeli, Parviraptor estesi, Marmoretta sp., Aviatyrannis jurassica.

Late Kimmeridgian (Lourinhã Formation, Amoreira-Porto Novo Member): Selenemys lusitanica, Plesiochelys sp., Cteniogenys reedi, Lusitanisuchus mitrocostatus, Rhamphorhynchus sp., Dracopelta zbyszewskii, Miragaia longicollum, Trimucrodon cuneatus, Camptosaurus aphanoecetes, Dinheirosaurus lourinhanensis, Turiasaurus sp., Ceratosaurus nasicornis, Torvosaurus aff. tanneri.

Around the Kimmeridgian/Tithonian boundary (Sobral Member): Selenemys lusitanica, Plesiochelys sp., Machimosaurus hugii, Rhamphorhynchus sp., Lourinhanosaurus antunesi, Lusotitan atalaiensis, Lourinhasaurus alenquerensis, Dryosaurus sp., cryptoclidid plesiosaur.

Early Tithonian (Sobral Member): Plesiochelys sp., Miragaia longicollum.

Upper early Tithonian (Bombarral Member): Plesiochelys sp., Allosaurus europaeus, Draconyx loureiroi, Stegosaurus sp.

Late Tithonian (Freixial Member): Plesiochelys sp., Theriosuchus sp. B, Ornithopoda sp. B. 

Despite the fragmentary occurrences of certain taxa, the chronology of some vertebrates seem to be age-restricted, and can thus be used for biostratigraphy. There is a peak of vertebrate fossil diversity and abundance near the Kimmeridgian/Tithonian boundary and a decline towards the end of the Tithonian. Is not yet understood if such trend represents true

diversity/abundance in the Jurassic or if it is caused by any geologic and taphonomic bias.

Ribeiro, V. Mateus O. (2012).  Chronology of the Late Jurassic dinosaur faunas, and other reptilian faunas, from Portugal. Journal of Vertebrate Paleontology, Program and Abstracts, 2012, p. 161 ISSN 1937-2809.
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Época de escavações 2011

Estou em época de escavações, que este ano começou em Maio e se estende até meados de Agosto, procurando dinossauros e outros vertebrados por todo o Mesozóico Português  e também com quase um mês de trabalho de campo em Angola.
 Em Portugal, o trabalho é focado na Lourinhã, de onde recolhemos mais ovos de dinossauro carnívoro. Em Angola, recolhemos mosassauros, plesiossauros, pterossauros, crocodilos, baleias e... dinossauros, integrado no Projecto PaleoAngola.

Pegadas de dinossauro em Angola