England dinosaurs
76656476
A REASSESSMENT OF THE PHYLOGENETIC POSITION OF CRETACEOUS SAUROPOD DINOSAURS FROM QUEENSLAND, AUSTRALIA
The Cretaceous sauropod material from Queensland, Australia, has been regarded as pertaining to a persistently primitive sauropod lineage e.g. Coombs and Molnar) The specimens derive from the Toolebuc and Allaru (Albian marine) and Winton (Cenomanian continental) Formations. Recent phylogenetic analyses carried out by workers in Argentina, the USA and England permit a reassessment of this fragmentary material. As far as can be ascertained from the material, there is no indication from the character states that more than a single taxon is represented. Character states diagnostic of the Titanosauriforrnes, the Titanosauria, the Somphospondyli and the Titanosauridae are present. Thus the Queensland material does not pertain to cetiosaurids but belongs to titanosaurs, extending their range into Australia. KEY WORDS. Sauropods. Austrosaurus. Titanosaurs. Cretaceous. Paleozoogeography.
Ralph E Molnar
128617817
Armored dinosaurs(Ornithischia: Ankylosauria) from the Middle and Upper Jurassic of England
Abstract Hitherto the earliest positive record of ankylosaurs(armored dinosaurs) has been from beds well up in the Lower Cretaceous; in fact, however, specimens referable to the ankylosaurian family Nodosauridae are present in the Middle and Upper Jurassic of England: from the Middle Callovian [partial mandible Sarcolestes leedsi Lydekker the Upper Oxfordian [femur Cryptodraco eumerus Seeley maxilla Priodontognathus phillipsii Seeley and the Upper Tithonian [caudal vertebra, tooth] The Tithonian tooth and those of Priodontognathus are large and similar to those of the nodosaurids Priconodon and Sauropelta (Lower Cretaceous, U.S.A. The incomplete mandible of Sarcolestes is similar to that of Sauropelta with a dermal scute fused to the lateral surface, and a tooth row extending to the anterior end of the jaw; an unusual feature is the caniniform first tooth. The quadrupedal ankylosaurs and stegosaurs probably represent separate evolutionary lines that extend back at least into the Lower Jurassic, and both lines probably evolved from ornithopod dinosaurs that were bipedal. Nodosaurid ankylosaurs occur in Europe from the Middle Jurassic to Late Cretaceous and probably reached North America via a filter route in the early Cretaceous.
Peter M Galton
84521850
The palaeoecology of the dinosaurs of the Wessex Formation (Wealden Group, Early Cretaceous) Isle of Wight, Southern England
Abstract The Wessex Formation on the Isle of Wight yields an Early Cretaceous dinosaur fauna. Sedimentological evidence shows that this represents a mosaic of fluvial, floodplain and lacustrine environments within a relatively narrow east west oriented valley. The vegetational cover on the alluvial plain had a savannahor chaparral like aspect, probably of low productivity. The relative scarcity of small aquatic vertebrates, absence of coals, abundance of oxidixed sediments and the presence of immature calcretes indicate seasonal water supply. The dinosaur taxa compising the Wessex Formation faunal assemblage represent a single palaeocommunity which inhabited the local alluvial plain, although some species may have been transient. The fauna had a relatively low diversity and this is attributed to the low productivity of the local vegetation. Iguanodontids and Hypsilophodon were the dominant elements in the fauna. In contrast to Late Jurassic dinosaur faunas, sauropods are less abundant in the Wessex Formation, although they remain taxonomically diverse. It is concluded that climatic changes which took place in the Late Jurassic or Early Cretaceous resulted in the appearance of flow productivity vegetation and that this was incapable of supporting large sauropod populations.
Allan N Insole Stephen Hutt
198411385
The Early Cretaceous brachiosaurid dinosaurs Ornithopsis and Eucamerotus from the Isle of Wight, England
William T Blows
140583717
Stegosaurian Dinosaurs from the Bathonian(Middle Jurassic) of England, the earliest record of the family Stegosauridae
Abstract The earliest records of stegosaurian dinosaurs of the family Stegosauridae are a few isolated bones from the Bathonian (Middle Jurassic) of southern England. A massive femur of a juvenile individual from the Lower Cornbrash (top of Upper Bathonian) of Oxfordshire is tentatively referred to the genus Lexovisaurus Hoffstetter as L. vetustus Huene Four other bones from the Lower Bathonian are tentatively referred to this taxon: two incomplete vertebrae from the Sharp's Hill Formation of Oxfordshire and two large and massive dermal plates from the underlying Chipping Norton Formation (basal Bathonian) of Gloucestershire.
Peter M Galton H Philip Powell
92401806
Regular ArticleThe palaeoecology of the dinosaurs of the Wessex Formation (Wealden Group, Early Cretaceous) Isle of Wight, Southern England
The Wessex Formation on the Isle of Wight yields an Early Cretaceous dinosaur fauna. Sedimentological evidence shows that this represents a mosaic of fluvial, floodplain and lacustrine environments within a relatively narrow east west oriented valley. The vegetational cover on the alluvial plain had a savannahor chaparral like aspect, probably of low productivity. The relative scarcity of small aquatic vertebrates, absence of coals, abundance of oxidixed sediments and the presence of immature calcretes indicate seasonal water supply. The dinosaur taxa compising the Wessex Formation faunal assemblage represent a single palaeocommunity which inhabited the local alluvial plain, although some species may have been transient. The fauna had a relatively low diversity and this is attributed to the low productivity of the local vegetation. Iguanodontids and Hypsilophodon were the dominant elements in the fauna. In contrast to Late Jurassic dinosaur faunas, sauropods are less abundant in the Wessex Formation, although they remain taxonomically diverse. It is concluded that climatic changes which took place in the Late Jurassic or Early Cretaceous resulted in the appearance of flow productivity vegetation and that this was incapable of supporting large sauropod populations.
Allan N Insole Stephen Hutt
129184844
Non avian theropod dinosaurs from the early Late Cretaceous of central Europe
Abstract Quantitative and qualitative analyses of isolated teeth and postcranial elements of non avian theropod dinosaurs from the Upper Cretaceous (Santonian) Csehbanya Formation, Iharkut (western Hungary) indicate that these remains represent multiple dinosaur groups. Based on comparative and statistical analyses, 58 teeth and tooth fragments are identified as belonging to medium sized basal tetanuran theropods that may have represented the top predator of the terrestrial Iharkut ecosystem. These teeth are almost identical with the two Megalosaurus pannoniensis teeth from the lower Campanian of Muthmannsdorf (Austria) and show a notable similarity to teeth of the Middle Jurassic M bucklandii and the Lower Cretaceous M dunkeri from England. A single pedal ungual phalanx is interpreted as the oldest European occurrence of Late Cretaceous abelisaurids, as suggested by a ventral groove and bifurcated grooves laterally bordering a convex, triangular area. Small bodied paravian theropods are found to be the best represented group in Iharkut, including teeth, caudal vertebrae, a metacarpal III, manual phalanges, and a fragmentary left tibia. A particularly notable paravian remain is a complete left scapulocoracoid possessing a unique pneumatic foramen ventral to the coracoid foramen. This specimen is assigned to Pneumatoraptor fodori n. g. et sp. Finally, numerous postcranial elements of Theropoda indet. were recovered, including a fragmentary sacrum that offers new insights into the sacral pneumaticity of theropods. The presence of these theropods in the Santonian Iharkut ecosystem provides the first evidence that during the early Late Cretaceous the Mediterranean archipelago was inhabited by both Gondwanan and Euramerican members of theropod dinosaurs. Consistent with data available for other archosaurian taxa, the close relationship of the basal tetanuran teeth with much older forms suggests that the Iharkut area may have functioned as a refugium in the early Late Cretaceous Mediterranean archipelago.
Attila Osi Sebastian Apesteguia Michal Kowalewski
83877447
Reassessment of the Lower Cretaceous (Barremian) pliosauroid Leptocleidus superstes Andrews, 1922 and other plesiosaur remains from the nonmarine Wealden succession of southern England
The Lower Cretaceous (upper Berriasian to lowermost Aptian) nonmarine Wealden succession of southern England has been a prolific source of vertebrate fossils for over 180 years. The sequence is most famous for terrestrial reptiles, particularly dinosaurs; however, significant aquatic tetrapod discoveries including rare nonmarine plesiosaurs have also been reported. The record of Wealden plesiosaurs currently incorporates a single valid taxon, Leptocleidus superstes Andrews, 1922a, based on a partial skeleton and skull from the Barremian Upper Weald Clay Formation of Berwick, Sussex. Traditional classifications place this plesiomorphic pliosauroid with basal Jurassic rhomaleosaurids; however, the genus Leptocleidus has since become a 'waste basket' for various Cretaceous rhomaleosaurid like plesiosaurs from around the globe. In an attempt to clarify this situation, the type specimen of L. superstes was reexamined and redescribed. Previously unrecorded anatomical features were identified including an elongate, gracile paraoccipital process on the exoccipital opisthotic, and tooth ornament comprising widely spaced, coarse striations that are restricted to the lingual surface of the crown (mesiodistal 'carinae' are absent) Other indeterminate pliosauroid remains (recovered along with coeval elasmosaurids) from the upper Berriasian Valanginian Hastings Beds Group also exhibit potentially diagnostic traits: an atlas centrum with no anterolateral exposure and with ventral margin formed by the intercentrum; a single headed rib articulation on the atlas centrum extending onto the axis centrum; and epipodials that are longer than broad. The placement of L. superstes is controversial in recent phylogenies. To test the competing hypotheses, L. superstes together with all closely related species were rescored into the most comprehensive published phylogenetic data sets of Plesiosauria and Pliosauroidea. Separate maximum parsimony and Bayesian analyses of each matrix unanimously supported a relationship between L. superstes and pliosauroids but could not confirm placement within either Rhomaleosauridae sensu stricto, or a discrete 'leptocleidoid' clade. Examination of character states advocating affinities amongst Leptocleidus spp. suggests homoplasy rather than clear homology between what are potentially palaeobiogeographically disparate genus level taxa. (c) 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 161, 663 691.
Benjamin P Kear Paul M Barrett
129793662
The Wealden (non marine Lower Cretaceous) of the Wessex Sub basin, southern England
Abstract The Wealden Beds (non marine Lower Cretaceous) of the Wessex Sub basin, southern England, are exposed principally in coastal sections on the Isle of Wight and in Dorset. Geological Conservation Review sites within these strata have been extensively documented since the earliest days of geological enquiry in Great Britain. The succession is dominated by the alluvial Wessex Formation which demonstrates a broad east west transition from meanderplain lithofacies to coarser grained alluvial sediments, in relative proximity to the Cornubian source massif. The meanderplain sediments on the Isle of Wight are of international importance for their plant and animal fossils, the latter including many dinosaurs and their trackways. Upper Barremian transgression resulted in the spread of muddy lakes and coastal lagoons from the Weald Sub basin into the eastern part of the Wessex Sub basin, around or through the Purbeck Isle of Wight structure. The resulting richly fossiliferous mudrock dominated strata are now represented by the Vectis Formation on the Isle of Wight and in Swanage Bay, Dorset. The Geological Conservation Review sites in the Wessex Sub basin are documented and interpreted, with particular reference to research history, chronostratigraphy, structural context, palaeoenvironments, palaeobiology and palaeoclimatology. New directions for research are proposed, as applicable.
Jonathan D Radley Percival Allen
129351673
A reappraisal of a putative record of abelisauroid theropod dinosaur from the Middle Jurassic of England
Abstract Abelisauroidea are a recently recognized clade of theropod dinosaurs that have a predominantly Gondwanan distribution. Recently, a distal theropod tibia from the Middle Jurassic of England was identified as an abelisauroid, representing one of the oldest records of the group in general and the only Jurassic occurrence in Europe. On this basis, rapid radiation of abelisauroid and a global distribution of this clade in the Jurassic were suggested. Here, the specimen in question is re examined and the characters used for referral to the Abelisauroidea are re evaluated. None of the proposed characters can be demonstrated to represent abelisauroid synapomorphies and all have a wider distribution; especially coelurosaurian theropods, which are known from contemporaneous beds in England, frequently show the same character combination. Thus, there is currently no secure evidence for the occurrence of abelisauroids in the Jurassic of the northern Hemisphere, and the early evolution of this clade remains poorly known. Furthermore, other fragmentarily known taxa previously referred to Abelisauroidea based on putative synapomorphies of the distal tibia, such as Ozraptor and Austrocheirus should be considered as Theropoda indet.
Oliver W M Rauhut