Sauropod dinosaurs from the central Zambezi Valley, Zimbabwe, and the age of the Kadzi Formation.

La evolución de los arcosaurios durante el Jurásico: una perspectiva desde el Sur.

Article

Full-text available

Dec 2008

The Tendaguru Formation (Late Jurassic to Early Cretaceous, southern Tanzania): definition, palaeoenvironments, and sequence stratigraphy

Article

Full-text available

Aug 2009

The well-known Late Jurassic to Early Cretaceous Tendaguru Beds of southern Tanzania have yielded fossil plant remains, invertebrates and vertebrates, notably dinosaurs, of exceptional scientific importance. Based on data of the German-Tanzanian Tendaguru Expedition 2000 and previous studies, and in accordance with the international stratigraphic guide, we raise the Tendaguru Beds to formational rank and recognise six members (from bottom to top): Lower Dinosaur Member, Nerinella Member, Middle Dinosaur Member, Indotrigonia africana Member, Upper Dinosaur Member, and Rutitrigonia bornhardti-schwarzi Member. We characterise and discuss each member in detail in terms of derivation of name, definition of a type section, distribution, thickness, lithofacies, boundaries, palaeontology, and age. The age of the whole formation apparently ranges at least from the middle Oxfordian to the Valanginian through Hauterivian or possibly Aptian. The Tendaguru Formation constitutes a cyclic sedimentary succession, consisting of three marginal marine, sandstone-dominated depositional units and three predominantly coastal to tidal plain, fine-grained depositional units with dinosaur remains. It represents four third-order sequences, which are composed of transgressive and highstand systems tracts. Sequence boundaries are represented by transgressive ravinement surfaces and maximum flooding surfaces. In a more simple way, the depositional sequences can be subdivided into transgressive and regressive sequences/systems tracts. Whereas the transgressive systems tracts are mainly represented by shallow marine shoreface, tidal channel and sand bar sandstones, the regressive systems tracts predominantly consist of shallow tidal channel, tidal flat, and marginal lagoonal to supratidal deposits. doi:10.1002/mmng.200900004

A brachiosaurid sauropod from the Late Jurassic Cañadón Calcáreo Formation of Chubut, Argentina

Article

Full-text available

Aug 2006

Oliver W M Rauhut

Fragmentary sauropod remains from the Late Jurassic (Tithonian) Cañadón Calcáreo Formation of Chubut, Argentinean Patagonia, are derived from a taxon of large size, but with very slender forelimbs. The characters of the caudal vertebrae, such as anteriorly placed neural arches, slender forelimbs, and large deltopectoral crest of the humerus indicate that this material represents the first brachiosaurid sauropod reported from South America. This occurrence confirms an almost global distribution of brachiosaurids in the Late Jurassic and thus indicates a rapid diversification and dispersal of this group after its origin, presumable in the late Middle Jurassic. Fragmentarische Sauropoden-Reste aus der oberjurassischen Cañadón Calcáreo Formation (Tithon) in Chubut, argentinisches Patagonien, repräsentieren ein großes Taxon mit sehr schlanken Extremitäten. Die Charakteristika der Schwanzwirbel, wie etwa die vorne auf den Centra sitzenden Neuralbögen, schlanke Vorderextremitäten und der sehr gut entwickelte Deltopectoral-Kamm auf dem Humerus deuten darauf hin, dass es sich um den ersten Nachweis eines Brachiosauriden aus Südamerika handelt. Dieser Nachweis betont die offenbar fast globale Verbreitung dieser Gruppe im oberen Jura und deutet auf ein rasche Verbreitung und Diversifikation dieser Gruppe nach ihrer Entstehung, vermutlich im späten Mitteljura hin. doi:10.1002/mmng.200600010

Archosaur evolution during the Jurassic: A Southern perspective

Article

Full-text available

Dec 2008

The fossil record of archosaurs - crocodylomorphs, pterosaurs and dinosaurs - from the Jurassic of the Southern Hemisphere is critically reviewed, and its evolutionary implications are evaluated. Although several important faunas and also isolated finds are known from Gondwana, the record in total is still very patchy, and any evolutionary scenario based on this record should be seen as tentative. Compared to the Northern Hemisphere, southern archosaurs are much more poorly known, which is especially true for terrestrial crocodiles and pterosaurs. Marine crocodiles are rather well represented in south-western South America, whereas the report of terrestrial archosaurs is currently best for Africa. However, in South America, important and especially promising archosaur faunas are known from the Callovian Cañadón Asfalto and the (?)Tithonian Cañadón Calcáreo formations of Chubut province, Argentina. Early and Middle Jurassic Gondwanan archosaurs demonstrate that the faunas of that period still had a generally Pangean distribution, whereas first indications of differential archosaur evolution in the Northern and Southern Hemispheres are evident in Late Jurassic Gondwanan faunas.

The Tendaguru Formation (Late Jurassic to Early Cretaceous, southern Tanzania): definition, palaeoenvironments, and sequence stratigraphy

Article

Full-text available

Aug 2009
Mitt Mus Natur Be Geowissen Reihe

The well-known Late Jurassic to Early Cretaceous Tendaguru Beds of southern Tanzania have yielded fossil plant remains, invertebrates and vertebrates, notably dinosaurs, of exceptional scientific importance. Based on data of the German-Tanzanian Tendaguru Expedition 2000 and previous studies, and in accordance with the international stratigraphic guide, we raise the Tendaguru Beds to formational rank and recognise six members (from bottom to top): Lower Dinosaur Member, Nerinella Member, Middle Dinosaur Member, Indotrigonia africana Member, Upper Dinosaur Member, and Rutitrigonia bornhardti-schwarzi Member. We characterise and discuss each member in detail in terms of derivation of name, definition of a type section, distribution, thickness, lithofacies, boundaries, palaeontology, and age. The age of the whole formation apparently ranges at least from the middle Oxfordian to the Valanginian through Hauterivian or possibly Aptian. The Tendaguru Formation constitutes a cyclic sedimentary succession, consisting of three marginal marine, sandstone-dominated depositional units and three predominantly coastal to tidal plain, fine-grained depositional units with dinosaur remains. It represents four third-order sequences, which are composed of transgressive and highstand systems tracts. Sequence boundaries are represented by transgressive ravinement surfaces and maximum flooding surfaces. In a more simple way, the depositional sequences can be subdivided into transgressive and regressive sequences/systems tracts. Whereas the transgressive systems tracts are mainly represented by shallow marine shoreface, tidal channel and sand bar sandstones, the regressive systems tracts predominantly consist of shallow tidal channel, tidal flat, and marginal lagoonal to supratidal deposits. doi:10.1002/mmng.200900004

A brachiosaurid sauropod from the Late Jurassic Cañadón Calcáreo Formation of Chubut, Argentina

Article

Full-text available

Aug 2006
Mitt Mus Natur Be Geowissen Reihe

Oliver W M Rauhut

Fragmentary sauropod remains from the Late Jurassic (Tithonian) Cañadón Calcáreo Formation of Chubut, Argentinean Patagonia, are derived from a taxon of large size, but with very slender forelimbs. The characters of the caudal vertebrae, such as anteriorly placed neural arches, slender forelimbs, and large deltopectoral crest of the humerus indicate that this material represents the first brachiosaurid sauropod reported from South America. This occurrence confirms an almost global distribution of brachiosaurids in the Late Jurassic and thus indicates a rapid diversification and dispersal of this group after its origin, presumable in the late Middle Jurassic. Fragmentarische Sauropoden-Reste aus der oberjurassischen Cañadón Calcáreo Formation (Tithon) in Chubut, argentinisches Patagonien, repräsentieren ein großes Taxon mit sehr schlanken Extremitäten. Die Charakteristika der Schwanzwirbel, wie etwa die vorne auf den Centra sitzenden Neuralbögen, schlanke Vorderextremitäten und der sehr gut entwickelte Deltopectoral-Kamm auf dem Humerus deuten darauf hin, dass es sich um den ersten Nachweis eines Brachiosauriden aus Südamerika handelt. Dieser Nachweis betont die offenbar fast globale Verbreitung dieser Gruppe im oberen Jura und deutet auf ein rasche Verbreitung und Diversifikation dieser Gruppe nach ihrer Entstehung, vermutlich im späten Mitteljura hin. doi:10.1002/mmng.200600010

The first confirmed sauropod dinosaur from Ethiopia discovered in the Upper Jurassic Mugher Mudstone

Article

Jul 2019
J AFR EARTH SCI

Ethiopia preserves extensive Mesozoic non-marine sedimentary sequences, but dinosaur fossils are exceptionally rare. The record is limited to a handful of theropod and ornithischian teeth from the Upper Jurassic Mugher Mudstone of the eastern margin of the Northwest Plateau, which has otherwise produced a diverse vertebrate fossil assemblage including actinopterygians, dipnoans, testudineans, crocodyliforms, and mammaliaforms. Here, we report the discovery of the first confirmed sauropod dinosaur from Ethiopia. The tooth BST VP-1/1 comes from a fine-to medium-grained, pebble and clast-rich zone with concentrated lenses of vertebrate microfossils in the lower part of the Mugher Mudstone. BST VP-1/1 is broad crowned, complete to the root, and slightly ellipsoidal midway in cross-section proximally toward the root. The distal half of the tooth has a chisel like appearance. BST VP-1/1 is planar lingually, convex labially, and narrows apically. These features compare closely with those of early macronarians, such as Giraffatitan brancai from the penecontemporaneous Tendaguru Formation in Tanzania. This specimen demonstrates the presence of sauropods in Ethiopia for the first time, and indicates that macronarians were widespread in East Africa during the Late Jurassic Epoch.

Late Jurassic paleoclimate of Central Africa

Article

Sep 2011
PALAEOGEOGR PALAEOCL

The first dinosaur from the Jurassic Aliança Formation of northeastern Brazil, west Gondwana: A basal Neotheropoda and its age and paleobiogeographical significance

Article

May 2022
J S AM EARTH SCI

In South America, little is known about Jurassic dinosaurs, contrasting with the extensive record of the late Triassic and Cretaceous, mainly in a vast area corresponding to the northern half of South America (west Gondwana). Herein, we describe for the first time a theropod dinosaur recovered from the Aliança Formation of the Jatobá Basin, represented by a caudal vertebra. Compared with theropods from the Jurassic, the specimen from Brazil is closer related to the basal neotheropods such as Dilophosaurus wetherilli, from the early Jurassic of North America. Basal neotheropods exhibited a worldwide distribution during the early Jurassic period, as suggested by the record in North America, South Africa and Antarctica. Thus, the new record from the Brazil suggests the survival of the basal lineage represented by Dilophosaurus and close relatives during the Middle-Late Jurassic. The new fossil occurrence described here also enables a worldwide correlation, reinforcing a Jurassic rather than a Late Triassic age for the Aliança Formation, for which it is provisionally assigned a Middle-Late Jurassic age.

New theropod remains from the Late Jurassic Cañadón Calcáreo formation of Chubut, Argentina

Article

Jun 2021
J S AM EARTH SCI

Late Jurassic South American theropod faunas are still extremely poorly known, with large-sized ceratosaurids and megalosaurids having been identified on the basis of isolated teeth, whereas the only named taxa, Chilesaurus and Pandoravenator, are probable tetanurans of uncertain affinities. Here we describe two new specimens of medium-sized to large theropods from the Oxfordian-Kimmeridgian Cañadón Calcáreo Formation of Chubut, Argentina; an isolated and rather well-preserved anterior cervical vertebra and a very fragmented, but associated assortment of bones, including cranial and vertebral remains. Both specimens show ceratosaurian and, most probably abelisaurid affinities. A faunal analysis underlines the relative abundance of ceratosaurs and the absence of coelurosaurs as main differences of Late Jurassic Gondwanan theropod faunas from their Laurasian counterparts. The presence of abelisaurids in both the Tendaguru Formation and the Cañadón Calcáreo Formation indicates a wide distribution of this clade already in the Late Jurassic in the Southern Hemisphere.

Considerations on the age of the Tiouaren Formation (Iullemmeden Basin, Niger, Africa): imolications for Gondwanan Mesozoic terrestrial vertebrate faunas

Article

Jan 2009
PALAEOGEOGR PALAEOCL

Systematic study of the historical material of Upper Cretaceous reptiles from the Tremp Basin (Catalonia, Spain) housed at the MNCN

Conference Paper

Full-text available

Sep 2016

Martín Jiménez M, Sánchez-Chillón B, Escaso F, Mocho P, Narváez I, Ortega F, Pérez-García A. 2016. Systematic study of the historical material of Upper Cretaceous reptiles from the Tremp Basin (Catalonia, Spain) housed at the MNCN. p. 93-94. In: Torcida Fernández-Baldor F, Canudo JI, Huerta P, Pereda X (eds.), Abstract book of the VII International Symposium about Dinosaurs Palaeontology and their Environment.

The theropod dinosaur Elaphrosaurus bambergi Janensch, 1920, from the Late Jurassic of Tendaguru, Tanzania

Article

Apr 2016

Theropod dinosaurs from the Late Jurassic of Gondwana are still poorly known, with Elaphrosaurus bambergi Janensch, 1920, from the late Kimmeridgian of Tendaguru, Tanzania, being the only taxon represented by more than isolated remains from Africa. Having long been considered a coelurosaurian, more specifically an ornithomimosaur, Elaphrosaurus is currently regarded as a basal ceratosaur. Here, we revise the osteology and phylogenetic position of this important taxon. Elaphrosaurus shows many unusual osteological characters, including extremely elongated and constricted cervical vertebrae, an expansive shoulder girdle with strongly modified forelimbs, a relatively small ilium, and elongate hindlimbs with a very small ascending process of the astragalus that is fused to the tibia. We found this taxon to share many derived characters with noasaurids, such as: strongly elongate cervical and dorsal vertebrae; low, rectangular neural spines in the mid-caudal vertebrae; presence of only an anterior centrodiapophyseal lamina in anterior caudal vertebrae; presence of a wide, U-shaped notch between the glenoid and the anteroventral hook in the coracoid; a laterally flared postacetabular blade of the ilium; a flat anterior side of the distal tibia; and a reduced shaft of metatarsal II. Our analysis placed Elaphrosaurus within a dichotomous Noasauridae as part of a Jurassic subclade, here termed Elaphrosaurinae, that otherwise includes taxa from eastern Asia. These results underscore the long and complex evolutionary history of abelisauroids, which is still only beginning to be understood.

A diplodocid sauropod dinosaur from the Late Jurassic Cañadón Calcáreo Formation of Chubut, Argentina

Article

Full-text available

Aug 2015

Late Jurassic dinosaur faunas from the Southern Hemisphere are still poorly known, and it thus remains unclear whether or not the famous Tendaguru fauna (Kimmeridgian–Tithonian, Tanzania) represents a typical Gondwanan dinosaur assemblage of that time. In South America, only the Oxfordian–Kimmeridgian Cañadón Calcáreo Formation of Chubut Province, Argentina, has yielded more than isolated Late Jurassic dinosaur remains so far. Here we report fragmentary remains of a dipolodocid sauropod from this unit, representing the first record of this family from the Late Jurassic of South America. Incorporating the basal macronarian Tehuelchesaurus, an unidentified brachiosaurid, the dicraeosaurid Brachytrachelopan, and the diplodocid described here, the taxonomic composition of the sauropod fauna from the Cañadón Calcáreo Formation is remarkably similar to that of the Tendaguru Formation, but also to roughly contemporaneous faunas in North America and Europe. The diverse non-neosauropodan sauropod fauna known from the early Middle Jurassic (Aalenian–Bajocian) of the same depositional basin within Chubut Province is congruent with the dominance of non-neosauropodan sauropods in continental faunas globally to at least the Bathonian. These assemblages suggest a rapid faunal turnover within sauropod faunas in the late Middle Jurassic-earliest Late Jurassic at least in western Pangea, through which basal eusauropods were replaced by diplodocoid and macronarian neosauropods. Taking paleogeographical reconstructions into account, this faunal replacement might have taken place in a surprisingly short time interval of maximally five million years close to the end of the Middle Jurassic.SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP

An unusually large theropod dinosaur tooth from the Kirkwood Formation (Lower Cretaceous) of South Africa

Article

Full-text available

Jan 2012
Neues Jahrbuch Geol Palaontol Abhand

The basal part of the crown is described for a very large theropod dinosaur tooth that probably came from the Kirkwood Formation (Lower Cretaceous) of Eastern Cape Province, South Africa. It originated from an animal as large, or possibly larger, than Tyrannosaurus rex, and thus probably represents a new taxon for the Kirkwood fauna and the largest theropod from that fauna. Examination of the fossil record indicates that very large theropods, approximating the size of Tyrannosaurus rex, occurred from the Callovian through the Maastrichtian. Such very large forms apparently evolved sequentially in several theropod clades.

Sedimentology and depositional environments of the Red Sandstone Group, Rukwa Rift Basin, southwestern Tanzania: New insight into Cretaceous and Paleogene terrestrial ecosystems and tectonics in sub-equatorial Africa

Article

Full-text available

May 2010
J AFR EARTH SCI

The Red Sandstone Group (RSG) in the Rukwa Rift Basin of southwestern Tanzania represents one of the only well-exposed, fossiliferous Cretaceous–Paleogene continental sedimentary sequences in sub-equatorial Africa. The significance of the RSG for reconstructing the paleoenvironmental and paleoclimatic history of African ecosystems during these critical time periods has been obfuscated by long-standing confusion and debate over the age of the deposits. Detailed stratigraphic, sedimentologic, and paleontologic investigations of the RSG conducted between 2002 and 2008 have produced a wealth of new fossil discoveries and data on lithofacies, alluvial architecture, sedimentary provenance, clay mineralogy and geochronology that resolve the long-standing debate over the age of these deposits. This study confirms the existence of an extensive middle Cretaceous sequence, herein named the Galula Formation, and subdivided into the Mtuka and Namba members. Moreover, we document the existence of a previously unrecognized late Paleogene continental sequence termed the Nsungwe Formation, which is divided into the Utengule and Songwe members. The Galula Formation represents a 600-3000 m thick sequence of amalgamated, braided fluvial deposits that were deposited across a large braidplain system via multiple parallel channels that had their source in the highlands of Malawi and Zambia. The middle Cretaceous Dinosaur Beds of Malawi are hypothesized to be at least partially correlative with the Galula Formation, and represent proximal deposits of this large, northwest flowing, trunk stream system. A moderately diverse terrestrial vertebrate fauna, including multiple species of dinosaurs, crocodyliforms, turtles, fishes and mammals have been recovered, along with a sparse aquatic molluscan fauna. Lithofacies and clay mineralogy indicate that Cretaceous paleoclimate ameliorated during deposition of the Galula Formation, transitioning from tropical semi-arid to tropical humid conditions.

Re-evaluation of Australodocus bohetii, a putative diplodocoid sauropod from the Tendaguru Formation of Tanzania, with comment on Late Jurassic sauropod faunal diversity and Palaeoecology

Article

Sep 2011
PALAEOGEOGR PALAEOCL

John A Whitlock

The Late Jurassic sauropod Australodocus bohetii was originally assigned to Diplodocidae, primarily on the basis of bifurcate neural spines. The holotype and paratype materials of A. bohetii are re-examined and found to have closer affinities with Brachiosaurus and relatives than with any diplodocoid. The presence of a second titanosauriform sauropod in the Tanzanian fauna is important for understanding the palaeoecology of the region. Comparisons between Tendaguru and three other contemporaneous sauropod faunas (Morrison Formation, USA; Lourinhã and Alcobaça formations, Portugal; Cañadón Calcáreo, Argentina) are also made. The revised Tendaguru fauna, with its high diversity of high-browsing Macronarians, now more closely matches the conifer-forest dominated landscape inferred from palaeobotanical evidence. The Morrison Formation, dominated by low-browse, is once again the only formation containing multiple diplodocids.

Considerations on the age of the Tiouaren Formation (Iullemmeden Basin, Niger, Africa): Implications for Gondwanan Mesozoic terrestrial vertebrate faunas

Article

Full-text available

Jan 2009
PALAEOGEOGR PALAEOCL

Pre-Aptian mid-Mesozoic terrestrial vertebrates from the African continent are still very poorly known. In Niger, the Tiouaren Formation in the Iullemmeden Basin has yielded dinosaur and other vertebrate remains, and this unit has been dated as Early Cretaceous, most probably pre-Aptian, on the basis of its fish fauna and geological relations to other units in the basin. A review of the fish fauna and invertebrates from this formation does not provide any evidence for such an age, and the geological relations only help to constrain the upper limit for the age of the formation (Aptian). In contrast, the described dinosaur taxa are phylogenetically nested with late Middle Jurassic to Early Late Jurassic taxa from other localities, and thus indicate a pre-Kimmeridgian, probably late Middle Jurassic age for the Tiouaren Formation. Under the assumption of such an age, the dinosaur fauna of this formation provides new insights into dinosaur faunal provincialism during the latest Middle Jurassic. Northern Gondwanan faunas of that time seem to have been different from southern Gondwanan faunas, and show closer affinities to Eurasian faunas than to the latter. A possible explanation for this might be a climatically controlled geographic barrier due to pronounced arid conditions and thus desert environments in central Gondwana during this time.

An enigmatic early Mesozoic dinosaur trackway from Zimbabwe

Article

Aug 2000

A trackway from Zimbabwe of probably the smallest dinosaur footprints recorded in Africa, is described and tentatively assigned to the Early Jurassic. The footprints are possibly those of a theropod and show strong negative (outward) rotation of the pes and are associated with manus prints. The shape of the footprints, unusual negative rotation, posterior curvature of digit IV and curious positioning of the manus prints in relation to the pes are enigmatic but somewhat reminiscent of Atreipus. Although a number of propositions are considered the most likely is that the animal was an immature dinosaur using a quadrupedal gait. A second trackway of slightly larger footprints of a bipedal theropod dinosaur is also recorded along with other diminutive tracks that suggest an early dinosaur assemblage, possibly dating from near the Trias‐sic‐Jurassic boundary.

Correlation of nonmarine Cretaceous strata of Africa and the Middle East

Article

Jun 1992

Nonmarine Cretaceous rocks of mainly Early to mid-Cretaceous age are found widely scattered throughout the African continent, including Madagascar and the Middle East. Correlation of these rocks between regions has been attempted in the northern part of Africa, but the less frequent outcrops south of the Sahara are poorly understood and correlations are very tentative. It is premature to attempt a continent-wide correlation scheme, but inter-regional correlations are presented to understand better the nonmarine Cretaceous throughout Africa and the Middle East. The Saharan region is dominated by nonmarine “Continentale Intercalaire” and “Nubian Sandstone” clastics of Early to mid-Cretaceous age, and in Egypt, locally Late Cretaceous. The rocks labelled “Nubian Sandstone” can be correlated into the Arabian Peninsular, where it was deposited around the Arabian craton prior to inundation by Tethyan transgressions. The opening of the South Atlantic invoked tectonic stresses forming pull-apart basins in West Africa, and exploited the Pan-African shear zone cutting central Africa forming basins from Nigeria to southern Sudan. Intracratonic basins in northern Sudan and Egypt resulted from tectonic stresses associated with the opening of the Red Sea and the northward convergence of Africa into the European continent. Nonmarine Cretaceous deposits in central and inland south-eastern Africa outcrop sporadically and are associated with regional extensional tectonics related to the separation of Madagascar. Coastal basins of Mozambique and South Africa containing marginal nonmarine Cretaceous facies appear to be associated with the separation of Madagascar and the Falkland Plateau from Africa. The ages of nonmarine Cretaceous strata in Africa and the Middle East are often imprecisely known, although recent palynostratigraphic results have improved precision. Vertebrate and megaplant fossils are found throughout the continent, but their biostratigraphic value is rather general. Nonmarine sedimentation in Africa and the Middle East is predominantly pre-Cenomanian, with some Upper Cretaceous rocks occurring in Egypt, Somalia, Yemen, Nigeria and Madagascar during regressive episodes.

Closely associated theropod trackways from the Jurassic of Zimbabwe

Article

Full-text available

Jan 2004

Eighty-eight tracks of large theropod dinosaurs were found in the mid-Jurassic of Zimbabwe. Among the tracks, at least five adjacent trackways are recorded. The adjacent tracks were probably made by animals traveling as a group, given that they are in relatively close succession; that there are three overlapping tracks (among just 23) suggesting reasonably close associations of the animals; that all the tracks are apparently of the same ichnotaxon; that the preservational types of the tracks are similar; and that the tracks are all of animals traveling in one general direction closely associated in time (there are no returning tracks of the same animals or of those of other species; presence of such tracks would be highly probable if the tracks were made over a period of time of even several hours). Nearby, recently discovered giant sauropod tracks, the first in sub-Saharan Africa, indicate a realistic potential of predator/prey interactions between the two groups of dinosaurs.

Taxonomic affinities of the putative titanosaurs from the Late Jurassic Tendaguru Formation of Tanzania: Phylogenetic and biogeographic implications for eusauropod dinosaur evolution

Article

Jan 2019

The Late Jurassic Tendaguru Formation of Tanzania, southeastern Africa, records a rich sauropod fauna, including the diplodocoids Dicraeosaurus and Tornieria, and the brachiosaurid titanosauriform Giraffatitan. However, the taxonomic affinities of other sympatric sauropod taxa are poorly understood. Here, we critically reassess and redescribe these problematic taxa, and present the largest phylogenetic analysis for sauropods (117 taxa scored for 542 characters) to explore their placement in Eusauropoda. Janenschia robusta has played a prominent role in discussions of titanosaur origins, with various authors referring at least some remains to Titanosauria, a clade otherwise known only from the Cretaceous. Redescription of the holotype of Janenschia, and all referable remains, supports its validity and placement as a nonneosauropod eusauropod. It forms a clade with Haestasaurus from the earliest Cretaceous of the UK, and the Middle/Late Jurassic Chinese sauropod Bellusaurus. Phylogenetic analysis and CT scans of the internal pneumatic tissue structure of Australodocus bohetii tentatively support a non-titanosaurian somphospondylan identification, making it the only known pre-Cretaceous representative of that clade. New information on the internal pneumatic tissue structure of the dorsal vertebrae of the enigmatic Tendaguria tanzaniensis, coupled with a full redescription, results in its novel placement as a turiasaur. Tendaguria is the sister taxon of Moabosaurus, from the Early Cretaceous of North America, and is the first turiasaur recognized from Gondwana. A previously referred caudal sequence cannot be assigned to Janenschia and displays several features that indicate a close relationship with Middle–Late Jurassic East Asian mamenchisaurids. It can be diagnosed by six autapomorphies, so we erect the new taxon Wamweracaudia keranjei gen. et sp. nov. The presence of a mamenchisaurid in the Late Jurassic of southern Gondwana indicates an earlier and more widespread diversification of this clade than previously realized, prior to the geographic isolation of East Asia. Our revised phylogenetic dataset sheds light on the evolutionary history of Eusauropoda, including supporting a basal diplodocoid placement for Haplocanthosaurus, and elucidating the interrelationships of rebbachisaurids. The Tendaguru Formation shares representatives of nearly all sauropod lineages with Middle Jurassic–earliest Cretaceous global faunas, but displays a greater range of diversity than any of those faunas considered individually. Biogeographic analysis indicates that the Tendaguru sauropod fauna was assembled as a result of three main phenomena during the late Early and/or Middle Jurassic: (1) invasions from Euramerica (brachiosaurids, turiasaurs); (2) endemism in west Gondwana (dicraeosaurids, diplodocids); and (3) regional extinctions that restricted the ranges of once widespread groups (mamenchisaurids, the Janenschia lineage). Multiple dispersals across the Central Gondwanan Desert are required to explain the distributions of Jurassic sauropods, suggesting that this geographic feature was at most a filter barrier that became easier to cross during the late Middle Jurassic.

Review of Janenschia Wild, with the description of a new sauropod from the Tendaguru beds of Tanzania and a discussion on the systematic value of procoelous caudal vertebrae in the sauropoda

Article

Mar 2000
Palaeontograph Abteilung

Since the holotype of Janenschia robusta (E. FRAAS) is based on an incomplete right hind limb, only specimens with comparable parts of the skeleton can be properly referred to that species. This is the case with the material from Tendaguru site P (JANENSCH 1925, 1929a), which consists of fore and hind limb skeletons from two individuals. The remaining sauropod skeletal material, i. e. the isolated anterior dorsal vertebrae, an articulated tail, and an anterior caudal vertebra, collected in the surroundings of Tendaguru Hill (JANENSCH 1929a) can not be properly referred to Janenschia due to the incompleteness of the type material of Janenschia robusta (E. FRAAS). Janenschia robusta (E. FRAAS) is redescribed and diagnosed, on the basis of the holotype and referred specimens from Tendaguru site P. Morphological comparisons suggest closer relationships between Janenschia and Camarasaurus. A new genus and species, Tendaguria tanzaniensis gen. et sp. nov. is proposed for two anterior dorsal vertebrae collected at Nambango (JANENSCH 1929a). Tendaguria gen. nov. is mainly diagnosed by extremely reduced neural spines which are not higher than the neural arch. They are connected with the postzygapophysial laminae and the epipophyses building a common dorsal plane. Comparison of these anterior dorsal vertebrae with those of different sauropod genera suggests that the vertebrae of Tendaguria gen. nov. represent the more derived type. The neural arch pattern in Tendaguria tanzaniensis gen. et sp. nov. points to a strong modification in the position and function of the episomatic musculature whose origin and insertion are both on these vertebrae. An articulated tail consisting of 30 caudal vertebrae collected at site G near Tendaguru Hill (JANENSCH 1929a), formerly referred to Janenschia and considered to have titanosaurid affinities, is described and compared to other titanosaurs. This caudal vertebrae series exhibits decreasing procoely posteriorly. The first 10 vertebrae are procoelous, the following 3 caudals are nearly amphiplatyan, and the last 17 are slightly amphicoelous. The procoelous condition in anterior caudal vertebrae is also known in Jurassic sauropods from China (e. g. Bellusaurus, Mamenchisaurus). This vertebral type was developed independently in different sauropod lineages. In the Late Cretaceous family Titanosauridae, all caudal vertebrae are characterized by procoely. It is concluded that sauropod families can not be distinguished by their procoelous anterior caudal vertebrae.

The second record of the African theropod Elaphrosaurus (Dinosauria, Ceratosauria) from the Western Hemisphere

Article

Sep 2001
Neues Jahrbuch Geol Palaontol Monatsh

Daniel J. Chure

The proximal end of a right tibia from Garden Park, CO. is the second bone of the theropod Elaphrosaurus from the Late Jurassic Morrison Formation and confirms an earlier Morrison record based on an isloated humerus. Its gracile form, the size and shape of the crista fibularis, and the outline of the proximal end closely match that of E. bambergi from the Middle Saurian Member of the Tendaguru Formation of Tanzania. The new specimen, like the African record, is Kimmeridgan in age.

Between Tendaguru and Bahariya: on the age of the Early Cretaceous dinosaur sites from the Continental Intercalaire and other African formations

Article

Jan 2012

Dinosaur Extinction

Chapter

Jun 2004

The disappearance of nonavian dinosaurs is only a small part of a greater class of extinctions known as “mass extinctions.” Mass extinctions are global events characterized by unusually high rates of extinction. The five episodes of mass extinctions in Earth history are the Permo-Triassic extinction, the Late Ordovician extinction, the Late Devonian extinction, the Triassic-Jurassic extinction, and the Cretaceous-Tertiary (K/T) extinction. This chapter focuses on patterns of geologic and biotic changes that occurred during the Cretaceous-Tertiary (K/T) extinction. It also highlights the similarities and differences in interpretations of geologic and fossil records. It concludes with two scenarios explaining the differing views about dinosaur extinction.

Dantas, P.; Pérez-Moreno, B.; Chure, D.; Silva, C.M. da; Santos, V.F dos; Póvoas, L.; Cachão, M.; Sanz, J.L.; Pires, C.; Bruno, G.; Ramalheiro, G. & Galopim de Carvalho, A.M. (1999) - O dinossáurio carnívoro Allosaurus fragilis no Jurássico superior português. Al-Madan, Almada, 8: 23-28.

Research

Full-text available

Jun 2015

Dantas, P.; Pérez-Moreno, B.; Chure, D.; Silva, C.M. da; Santos, V.F dos; Póvoas, L.; Cachão, M.; Sanz, J.L.; Pires, C.; Bruno, G.; Ramalheiro, G. & Galopim de Carvalho, A.M. (1999) - O dinossáurio carnívoro Allosaurus fragilis no Jurássico superior português. Al-Madan, Almada, 8: 23-28.

On the presence of Allosaurus fragilis (Theropoda: Carnosauria) in the Upper Jurassic of Portugal: First evidence of an intercontinental dinosaur species

Article

Jun 1999

The species Allosaurus fragilis, from the Morrison Formation of North America (Kimmeridgian-Tithonian, Upper Jurassic), is one of the best known members of the Theropoda, the group including all predatory non-avian dinosaurs and birds. Here, we report on the first diagnostic theropod remains discovered from the Jurassic of the Iberian Peninsula. The specimen is the first evidence of A. fragilis outside North America. Thus, this taxon represents the first dinosaur species found on two different continents, and suggests the existence of a 'land bridge' between North America and Europe during the Late Jurassic.

The phylogeny of Tetanurae (Dinosauria: Theropoda)

Article

Full-text available

Jun 2012
J SYST PALAEONTOL

Tetanuran theropods represent the majority of Mesozoic predatory dinosaur diversity and the lineage leading to extant Aves. Thus their history is relevant to understanding the evolution of dinosaur diversity, Mesozoic terrestrial ecosystems, and modern birds. Previously, the fragmentary and poorly sampled fossil record of basal (non-coelurosaur) tetanurans led to uncertainties regarding their basic interrelationships. This in turn prevented determining the relationships of many incompletely known taxa that nonetheless document a global radiation spanning more than 120 million years. We undertook an exhaustive examination of all basal tetanurans and all existing character data, taking advantage of recent discoveries and adding new morphological, temporal and geographic data. Our cladistic analysis of 61 taxa achieved significantly improved phylogenetic resolution. These results position several 'stem' taxa basal to a succession of monophyletic clades (Megalosauroidea, Allosauroidea and Coelurosauria). Megalosauroids include nearly 20 taxa arrayed amongst a basalmost clade (Piatnitzkysauridae, fam. nov.) and the sister taxa Spinosauridae and Megalosauridae; the latter includes two subfamilies, Megalosaurinae and Afrovenatorinae subfam. nov. Allosauroidea contains a diverse Metriacanthosauridae (= Sinraptoridae), Neovenatoridae, Carcharodontosauridae and a reduced Allosauridae. Finally, we assessed more than 40 fragmentary forms and hundreds of additional reported tetanuran occurrences. Tetanuran evolution was characterized by repeated acquisitions of giant body size and at least two general skull forms, but few variations in locomotor morphology. Despite parallel diversification of multiple lineages, there is evidence for a succession of 'dominant' clades. Tetanurae first appeared by the Early Jurassic and was globally distributed by the Middle Jurassic. Several major clades appeared prior to the breakup of Pangaea; as such their absence in specific regions, and at later times, must be due to poor sampling, dispersal failure and/or regional extinction. Finally, we outline a general perspective on Mesozoic terrestrial biogeography that should apply to most clades that appeared before the Late Jurassic.

Giant sauropod tracks from the Middle-Late Jurassic of Zimbabwe in close association with theropod tracks

Article

Dec 2004

Sauropod dinosaurs from the central Zambezi Valley, Zimbabwe, and the age of the Kadzi Formation.

Abstract

No full-text available

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