The Tendaguru Formation of south-eastern Tanzania has yielded the only diverse theropod fauna known from the Late Jurassic of Gondwana. Theropod remains have been recovered mainly from two members of the formation, the Middle and Upper Dinosaur members, which span from the Kimmeridgian to the latest Tithonian or earliest Cretaceous. Here, four of the described taxa and additional isolated remains from this formation are reviewed and evaluated. Labrosaurus(?) stechowi Janensch, and Megalosaurus(?) ingens Janensch, are based on isolated teeth that do not show any unique derived characters, so these taxa are regarded as nomina dubia. Nevertheless, the teeth show character combinations indicative of ceratosaurid and carcharodontosaurid relationships, respectively. Ceratosaurus? roechlingi Janensch was based on associated fragmentary remains, which probably represent more than a single taxon. None of the type material shows diagnostic characters, so the species is a nomen dubium, and a middle caudal vertebra with possibly ceratosaurid affinities is designated as the lectotype. Allosaurus(?) tendgurensis Janensch is based on an isolated, poorly preserved basal tetanuran tibia, which cannot be diagnosed, so the species is also a nomen dubium. A new taxon, Veterupristisaurus milneri gen. et sp. nov., is based on diagnostic caudal vertebrae from the Middle Dinosaur Member. These elements show carcharodontosaurid synapomorphies and, within this clade, share a unique derived character with the genus Acrocanthosaurus. In total, theropod material from the Tendaguru Formation indicates the presence of at least seven different species of theropods, including the ceratosaurian Elaphrosaurus bambergi Janensch, a probable ceratosaurid, a small abelisauroid, a probable abelisaurid, a small, noncoelurosaurian tetanuran, a possible megalosauroid and a carcharodontosaurid. Theropod faunas from the Middle and Upper Dinosaur members might differ slightly, but are similar in general taxonomic composition. In broad systematic terms, the theropod fauna from Tendaguru shows greater similarities to Cretaceous Gondwanan theropod faunas than with contemporaneous fauna from the North American Morrison Formation, indicating that the complex evolutionary and biogeographical history of Cretaceous Gondwanan theropod faunas can only be understood in the light of their Jurassic origins.

Memoirs of Museum Victoria, 2016

Novas, F.E., Aranciaga Rolando, A.M. and Agnolín, F.L. 2016. Phylogenetic relationships of the Cretaceous Gondwanan theropods Megaraptor and Australovenator: the evidence afforded by their manual anatomy. Memoirs of Museum Victoria 74: 49-61. General comparisons of the manual elements of megaraptorid theropods are conducted with the aim to enlarge the morphological dataset of phylogenetically useful features within Tetanurae. Distinctive features of Megaraptor are concentrated along the medial side of the manus, with metacarpal I and its corresponding digit being considerably elongated. Manual ungual of digit I is characteristically enlarged in megaraptorids, but it is also transversely compressed resulting in a sharp ventral edge. We recognize two derived characters shared by megaraptorans and coelurosaurs (i.e., proximal end of metacarpal I without a deep and wide groove continuous with the semilunar carpal, and metacarpals I and II long and slender), and one derived trait similar to derived tyrannosauroids (i.e., metacarpal III length <0.75 length of metacarpal II). However, after comparing carpal, metacarpal and phalangeal morphologies, it becomes evident that megaraptorids retained most of the manual features present in Allosaurus. Moreover, Megaraptor and Australovenator are devoid of several manual features that the basal tyrannosauroid Guanlong shares with more derived coelurosaurs (e.g., Deinonychus), thus countering our own previous hypothesis that Megaraptora is well nested within Tyrannosauroidea.

The paleobiogeography of the theropod clade Compsognathidae is here reaccessed in order to test the hypothesis of this taxon being adapted specifically to inhabit semi-arid environments. Data about localities where these fossils were collected and their paleoenvironments were gathered from the literature. Compsognathids seem to be found especially in sedimentary deposits known as Fossil Lagerstätten, which were formed under a set of specific conditions that allowed the preservation of the fragile bone remains of these animals. This bias limits an accurate analysis of the historical and/or ecological paleobiogeography of this taxon. Actually, it is possible that compsognathids had an almost worldwide distribution during the Mesozoic Era. Their occurrence in Lower Cretaceous rocks of China suggests that they also inhabited environments with moist conditions instead of being restricted to semi-arid to arid environments.

Atti della Società italiana di scienze …, 2005

New theropod remains from the Middle Jurassic (Bathonian) of NW Madagascar are described that include 49 isolated teeth and a dorsal vertebra. Being referable to at least three taxa, they provide a first insight into the high morphological biodiversity in the Middle Jurassic theropods. They may represent the oldest Gondwanan material referable to the Abelisauridae and Coelurosauria found up to today; however, lacking more exhaustive data on theropod dentition, their affinities remain uncertain pending more complete material.

A partial theropod skeleton from the Albian (ca. 105 ma) Cloverly Formation of Wyoming is shown to exhibit many features in common with members of Carcharodontosauria and is referred to Acrocanthosaurus atokensis on the basis of an autapomorphy and a unique combination of characters. The absence of neurocentral fusion in dorsal and caudal vertebrae and bone histology of the femur indicate that the specimen is a juvenile. The circumferences of lines of arrested growth were used to estimate mass over successive years of the animal's life. These mass estimates suggest that early in ontogeny, Acrocanthosaurus grew at rates on par with growth rates inferred in Allosaurus and most tyrannosaurid theropods, which are similar to rates expected for scaledup precocial birds. Histological data from adult specimens suggest that Acrocanthosaurus reached adult body size in two to three decades. Gigantism in Acrocanthosaurus likely evolved via acceleration of growth rates relative to those of basal members of Allosauroidea, a transition also observed within tyrannosauroid theropods. Contrary to previous assessments, there is only evidence for one large-bodied theropod species in the Early Cretaceous of North America, though many fragmentary specimens are indeterminate to the genus level. Aptian-Albian and Maastrichtian-aged dinosaur communities were more similar to one another than to those of the intervening Campanian stage in that both seem to have featured a single, extremely large-bodied, fast growing, geographically widespread theropod dinosaur.

Proceedings of the Royal Society B: Biological Sciences, 2011

The oldest theropod dinosaurs are known from the Carnian of Argentina and Brazil. However, the evolutionary diversification of this group after its initial radiation but prior to the Triassic -Jurassic boundary is still poorly understood because of a sparse fossil record near that boundary. Here, we report on a new basal theropod, Daemonosaurus chauliodus gen. et sp. nov., from the latest Triassic 'siltstone member' of the Chinle Formation of the Coelophysis Quarry at Ghost Ranch, New Mexico. Based on a comprehensive phylogenetic analysis, Daemonosaurus is more closely related to coeval neotheropods (e.g. Coelophysis bauri) than to Herrerasauridae and Eoraptor. The skeletal structure of Daemonosaurus and the recently discovered Tawa bridge a morphological gap between Eoraptor and Herrerasauridae on one hand and neotheropods on the other, providing additional support for the theropod affinities of both Eoraptor and Herrerasauridae and demonstrating that lineages from the initial radiation of Dinosauria persisted until the end of the Triassic. Various features of the skull of Daemonosaurus, including the procumbent dentary and premaxillary teeth and greatly enlarged premaxillary and anterior maxillary teeth, clearly set this taxon apart from coeval neotheropods and demonstrate unexpected disparity in cranial shape among theropod dinosaurs just prior to the end of the Triassic.

Acta Palaeontologica Polonica, 2012

The cervical vertebral series of Carnotaurus sastrei from Argentina is described in detail, and compared with Majungasaurus crenatissimus from Madagascar, both Late Cretaceous (Maastrichtian) in age. Notable differences in the morphology of the cervical vertebrae, especially in the shape and development of the epipophysis and the neural spines, are observed between these two genera. These differences show a neck much more robust in Carnotaurus than in Majungasaurus, may be linked to the evolution of the clade in relation to the divergence time since the two genera shared a common ancestor, and functionally may relate to the feeding function associated to the extreme reduction of the forelimbs.

2007

A new genus and species of diplodocid sauropod (Sauropoda, Diplodocoidea), Australodocus bohetii, is described. The type material from the Upper Jurassic (Tithonian) Tendaguru Beds of Tanzania, East Africa, consists of two successive mid-cervical vertebrae. These vertebrae do not show the extreme elongation of the cervical vertebrae that is diagnostic for Tornieria, and, apart from proportional differences, exhibit four autapomorphic characters not seen in other diplodocids: (1) pleurocoel weakly developed; (2) ridge posterolateral to the anterior condyle strongly posteroventrally orientated; (3) triangular pneumatic cavity ventral to the prezygapophysis, enclosed by the lateral ramus of the centroprezygapophyseal lamina and an anteriorly extended prezygodiapophyseal lamina; and (4) prominent prezygapophyseal process pointed, laterally keeled and surpassing the prezygapophysis anteriorly. Australodocus bohetii is the second diplodocid known from Tendaguru, and thereby the second diplodocid known from Gondwana. This impedes the customary reference of isolated East African diplodocid material to Tornieria, which can now only be assigned to Diplodocidae indet. The find supports previously proposed vicariance models of diplodocid palaeobiogeography.

2013

The theropod clade Carcharodontosauridae is a broadly distributed group of large allosauroid theropods. The carcharodontosaurids recorded in the Albian – Cenomanian of Gondwana are the youngest and most derived members of this clade. Tyrannotitan chubutensis, from the Cerro Castan˜ o Member of Cerro Barcino Formation (Albian; Chubut Group), Central Patagonia, Argentina, is of prime interest among Gondwanan carcharodontosaurids as it represents the oldest record of the group. Here we offer a detailed osteological comparative description of the holotype and paratype of Tyrannotitan chubutensis together with a new diagnosis of the species. The new information results in a better understanding of this taxon and Carcharodontosauridae. Furthermore, a comparative study of the anatomy of the pectoral girdle of Giganotosaurus is reinterpreted as very similar to that of Tyrannotitan and Mapusaurus. We also present a phylogenetic analysis of Carcharodontosauridae that recovers Tyrannotitan as a derived carcharodontosaurid, being the sister group of the clade formed by Giganotosaurus and Mapusaurus, all nested in the clade Giganotosaurini

Geology Today, 2001

2015

The dinosaur record in the South Pyrenees Basin is diverse and rich. A total of 142 theropod teeth were studied for this paper, which constitutes one of the richest samples for these remains in Europe. Eight upper Campanian to upper Maastrichtian outcrops from the Pyrenees produced six non-avian theropod taxa (Theropoda indet., Coelurosauria indet., ?Richardoestesia, ?Dromaeosauridae indet., ?Pyroraptor olympius, ?Paronychodon). These six taxa are added to two previously described theropods (a Richardoestesia-like form and a possible ornithomimosaurid), indicating that there was considerable theropod diversity on the Iberian Peninsula during the Late Cretaceous.

AI

Geological Magazine, 2005

Small theropod post-cranial material from Tendaguru, Tanzania, the only known Late Jurassic theropod locality in the Southern Hemisphere, is reviewed. Material originally described as 'coelurosaurs' includes at least one taxon of basal tetanuran and one taxon of small abelisauroid. Together with the abelisauroid Elaphrosaurus and the presence of a larger ceratosaur in Tendaguru, this material indicates that ceratosaurs were an important faunal element of Late Jurassic East African theropod faunas. One bone furthermore shares derived characters with the holotype of the poorly known Middle Jurassic Australian theropod Ozraptor and allows the identification of the latter as the oldest known abelisauroid, thus indicating an early divergence of ceratosaurids and abelisauroids within ceratosaurs. Abelisauroids might have originated in Gondwana and represent important faunal elements of Cretaceous Gondwanan theropod faunas in general.

Canadian Journal of Earth Sciences, 2021

The Dinosaur Park Formation (DPF) of Alberta, Canada, has produced one of the most diverse dinosaur faunas, with the record favouring large-bodied taxa, in terms of number and completeness of skeletons. Although small theropods are well documented in the assemblage, taxonomic assessments are frequently based on isolated, fragmentary skeletal elements. Here we reassess DPF theropod biodiversity using morphological comparisons, high-resolution biostratigraphy, and morphometric analyses, with a focus on specimens/taxa originally described from isolated material. In addition to clarifying taxic diversity, we test whether DPF theropods preserve faunal zonation/turnover patterns similar to those previously documented for megaherbivores. Frontal bones referred to a therizinosaur (cf. Erlikosaurus), representing among the only skeletal record of the group from the Campanian-Maastrichtian (83-66 Ma) fossil record of North America, plot most closely to troodontids in morphospace, distinct from non-DPF therizinosaurs, a placement supported by a suite of troodontid anatomical frontal characters. Postcranial material referred to cf. Erlikosaurus in North America is also reviewed and found most similar in morphology to caenagnathids, rather than therizinosaurs. Among troodontids, we document considerable morphospace and biostratigraphic overlap between Stenonychosaurus and the recently described Latenivenatrix, as well as a variable distribution of putatively autapomorphic characters, calling the validity of the latter taxon into question. Biostratigraphically, there are no broad-scale patterns of faunal zonation similar to those previously documented in ornithischians from the DPF, with many theropods ranging throughout much of the formation and overlapping extensively, possibly reflecting a lack of sensitivity to environmental changes, or other cryptic ecological or evolutionary factors.

Journal of Vertebrate Paleontology, 2002

We describe the osteology of the new small theropod dinosaur Masiakasaurus knopfleri, from the Late Cretaceous Maevarano Formation of northwestern Madagascar. Approximately 40% of the skeleton is known, including parts of the jaws, axial column, forelimb, pelvic girdle, and hind limb. The jaws of Masiakasaurus are remarkably derived, bearing a heterodont, procumbent dentition that is unknown elsewhere among dinosaurs. The vertebrae are similar to those of abelisauroids in the reduction of the neural spine, lack of pleurocoelous fossae on the centrum, and extensively pneumatized neural arch. The limb skeleton is relatively gracile and bears numerous abelisauroid synapomorphies, including a rounded humeral head, peg-and-socket iliac-pubic articulation, prominent femoral medial epicondyle, expanded tibial cnemial crest, and double-grooved pedal unguals. The femora and tibiae show evidence of dimorphism. More specific features shared between Masiakasaurus, the Argentine Noasaurus, and the Indian Laevisuchus suggest that these taxa form a clade (Noasauridae) within Abelisauroidea. This is supported by a cladistic phylogenetic analysis of 158 characters and 23 theropod taxa. Additionally, Ceratosauria is rendered paraphyletic in favor of a sister-taxon relationship between Neoceratosauria and Tetanurae that is exclusive of Coelophysoidea. The unique dental and jaw specializations of Masiakasaurus suggest deviation from the typical theropod diet. Finally, the distribution of noasaurids further supports a shared biogeographic history between South America, Madagascar, and India into the Late Cretaceous.

The model of dinosaur classification that was first proposed by Seeley in 1887that all dinosaurs can be grouped in to either Saurischia (lizard-hipped) or Ornithischia (bird-hipped)is one of the most prevalent ideas in the history of archosaur study. However, a recent large-scale phylogenetic analysis of early dinosaurs challenged this view and presented an alternative hypothesis in which Ornithischia and Saurischia did not share a sister-taxon relationship; Ornithischia and Theropoda were found to be sister-taxa (within a monophyletic Ornithoscelida), and a monophyletic Saurischia was recovered that comprised Sauropodomorpha and Herrerasauridae but not Theropoda. The Ornithoscelida-Saurischia (= Ornithoscelida-Pachypodosauria) model has subsequently been re-evaluated by a number of other studies and each of these has added to and modified the early dinosaur dataset of the original study.

Journal of Vertebrate Paleontology Program and Abstracts, 2015

A majority of recent phylogenetic analyses of Tetanurae (Dinosauria: Theropoda) place basal (= non-coelurosaurian) tetanurans into clades Megalosauroidea and Allosauroidea forming successively closer outgroups to Coelurosauria. However, the positions of genera Cryolophosaurus, Sinosaurus, Monolophosaurus and Acrocanthosaurus and clade Megaraptora remain controversial and a few phylogenetic analyses question the monophyly of both Megalosauroidea and Allosauroidea. This presentation re-evaluates the phylogeny of non-coelurosaurian Tetanurae by re-examining highly distinct and size- and ecomorphology-independent states of several characters used in previous analyses. Cryolophosaurus possesses a small lesser trochanter, indicating it is among the most basal neotheropods (Coelophysis, Dilophosaurus). Sinosaurus retains a distally expanded scapula of the most basal neotheropods but shares with Ceratosauria & Tetanurae a large lesser trochanter, suggesting that it is more derived than the former but less derived than the latter. Spinosauridae and Carcharodontosauridae (except Acrocanthosaurus and Eocarcharia) possess a lesser trochanter extending proximally to the ventral margin of femoral head and lack a maxillary fenestra, suggesting that they are the most basal tetanurans. Piatnitzkysauridae, Metriacanthosauridae, Neovenator, Megaraptora, Megalosauridae, Acrocanthosauridae (Acrocanthosaurus, Eocarcharia) and Allosauridae (Allosaurus, Saurophaganax) share with basal Coelurosauria (Zuolong, Tanycolagreus, Coelurus, Tyrannosauroidea) a lesser trochanter extending proximally to the middle of femoral head (lesser trochanter extends proximally to the dorsal margin of femoral head in Megaraptora, Tyrannosauridae, and ornithomimosaur Beishanlong). The above basal tetanurans and Monolophosaurus also share with Coelurosauria a maxillary fenestra. Megalosauridae, Monolophosaurus, Acrocanthosauridae and Allosauridae share with Coelurosauria a posteroventrally expanded surangular contact of dentary and a metacarpal IV less than 25% of metacarpal III or absent, forming a clade Avetheropoda. Monolophosaurus, Acrocanthosauridae and Allosauridae also share with basal Coelurosauria (Zuolong, Tanycolagreus, Tyrannosauroidea, Ornitholestes) a robust dorsal ramus of quadratojugal, forming a clade Euavetheropoda. Allosauridae share with Coelurosauria a medially open maxillary antrum (evolved independently in Metriacanthosauridae and Eocarcharia).

Journal of Paleontology, 1994

Revista del Museo Argentino de Ciencias Naturales, 2004

The Lato Cretaceous (Maas~richtian) Lameta Ihrmation of central India has yielded dissociated elements ofavariety ofpredatory dinosaurs, most ofthem comingfrom aquarry named the e~Carnosaur bed. The materials were described hv Huene and Matlev nearly 70 years ago. They recomized nine iheronod species, which they. "-.. sorted out into the theropod subgroups 4!arnosaiirian and eaCoelurasauria~~, I-iuene and Matley also described a considerable amount of theropod hindlimb bones (e.g., femora, tibiae, metat,arsals, and pedal phalanges) that they oilld not refer to any of these species, hut vaguely interpreted as corresponding to ~~allosaurid~~ or ,~coelurosaurid,~ theropods. We reviewed the available collection of Cretaceous therapods from Bara Simla housed at the Geological Survey of India. Kolkata. avrivlne to the foliowine conclusions: 1) Indosuchus and Indosaurus are abelisaurids, as-recognized by previous authors, hut avsilable information is not enough to judge whether they axi re synonyms; 2) Lmt~oisuchus indicus is a small abclisauroid, related to Noasaurus and Masiahasaurus on the basis or their peculiar cervical vortcbrae: 3: the coiitroversial taxa *Clorn~sosuc~ius-. ~iDruolosauroidesn, ,~Ornithornirnoides*. and also exhihit ahelisauroid characters. and bones of iaree size are tentatively referrod to as corresnondine to h~dosi~chus or Indosai~~zs, whereas some pedal bones of smaller size may belong to i,aeoisuckus; 5) two kinds of abelisaurid feet arcapparent: ansin which the nhaianpes ofdieit 111 andIVarerobust, and another typein which the iiliaianze-es. .-~. of digit IV are transversely narrow and dorsoventrally deep. This reviow demonstrates that all of the theropod eloments discovered at the ,,Carnosaur bed,) belong to a single theropod clade, tho Abelisauroidev.

New Mexico Museum of Natural History and Science Bulletin, 2003

Abstract—The Snyder quarry preserves one of the richest assemblages of Norian theropods in the world, and the second-most productive theropod locality in the Chinle Group. At least four coelophysid theropods are preserved at the Snyder quarry, based on tibiae. Most elements of these theropods are represented, including an incomplete skull and lower jaws, cervical, dorsal, sacral, and caudal vertebrae, a scapulocoracoid, ilia, ischia, femora, tibiae, a fibula, astragalocalcanea, and diverse carpals and tarsals. These specimens ...

Royal Society Open Science, 2019

Journal of Systematic Palaeontology, 2003

SYNOPSIS Titanosaurs represent approximately one-third of sauropod diversity and were geographically widespread throughout the Cretaceous, especially on southern continents. Titanosaurs evolved numerous appendicular synapomorphies that account for their specialised 'wide-gauge' limb posture, which can be recognised in their trackways. The macronarian origin of titanosaurs is only recently agreed upon and aspects of their interrelationships remain poorly understood. Titanosauria is named for the poorly known genus Titanosaurus, which was coined by Lydekker in 1877 on the basis of a partial femur and two incomplete caudal vertebrae. Fourteen species have since been referred to Titanosaurus, which distribute the genus across Argentina, Europe, Madagascar, India and Laos, and throughout 60 million years of the Cretaceous. Despite its centrality to titanosaur systematics and biogeography, the genus Titanosaurus has never been revised. A re-evaluation of all Titanosaurus species recognises as diagnostic only five. The type species T. indicus is invalid because it is based on 'obsolescent' characters-once diagnostic features that have gained a broader taxonomic distribution over time. Consequently, the genus Titanosaurus and its coordinated rank-taxa (e.g. Titanosaurinae, Titanosauridae, Titanosauroidea) must be abandoned. The unranked taxon Titanosauria, however, remains valid. A new phylogenetic taxonomy is proposed for Titanosauria that utilises nodes that have been judged stable by the most recent cladistic analyses. The early appearance of titanosaur ichnofossils (Middle Jurassic) and body fossils (Late Jurassic) precludes a vicariant origin for the group, but such a pattern cannot yet be ruled out for lower-level taxa within Titanosauria.

Canadian Journal of Earth Sciences, 2021

Well-sampled dinosaur communities from the Jurassic through the early Late Cretaceous show greater taxonomic diversity among larger (&gt;50 kg) theropod taxa than communities of the Campano-Maastrichtian, particularly to those of eastern/central Asia and Laramidia. The large carnivore guilds in Asiamerican assemblages are monopolized by tyrannosaurids, with adult medium-sized (50–500 kg) predators rare or absent. In contrast, various clades of theropods are found to occupy these body sizes in earlier faunas, including early tyrannosauroids. Assemblages with “missing middle-sized” predators are not found to have correspondingly sparser diversity of potential prey species recorded in these same faunas. The “missing middle-sized” niches in the theropod guilds of Late Cretaceous Laramidia and Asia may have been assimilated by juvenile and subadults of tyrannosaurid species, functionally distinct from their adult ecomorphologies. It is speculated that if tyrannosaurids assimilated the ni...

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