No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
... Padian (1984) noted that with Scleromochlus as a sister taxon to pterosaurs, "Huene probably got the flight scenario wrong, but the phylogeny right". Padian (1980Padian ( , 1983 favoured a bipedal terrestrial pterosaur origin as opposed to von Huene's arboreal Scleromochlus (though most researchers consider an arboreal origin for pterosaurs more likelye.g., Wellenhofer, 1991;Wild, 1984;Bennett, 1997Bennett, , 2008Unwin, 2005). Indeed, the possibility of saltation in Scleromochlus (see Benton, 1999) would lend support to Bennett's (1997) proposed leaping model for the origin of pterosaurian flight from the 'ground up' rather than 'trees down'; this was also linked to the more recent interpretation of pterosaur launching (Habib, 2008). ...
... The ankle (specifically the astragalus-calcaneum complex and its association with the tibia and fibula respectively) of archosaurs and related taxa has been a source of numerous cladistic characters and an important part of their classification (e.g., see Sereno and Arcucci, 1990;Sereno, 1991;Gower, 1996;Dyke, 1998). Pterosaurs have been considered to have a more basal mesotarsal joint (Wellenhofer, 1978;Wild, 1984), however this resembles that of derived archosaurs and others (Bennett, 1996a(Bennett, , 1996bKellner, 2004) considered pterosaurs to have an 'advanced mesotarsal joint' (in common with avemetatarsalians) supporting an ornithodiran position. Kellner (2004) also noted some 'crocodile-reversed' ankle features which would place them within basal Archosauria. ...
Our understanding of the pterosaurs' place within the reptilian lineage has had a long and complex history. The unusual morphology of pterosaurs, which is inextricably linked to their habit of powered flight, has generated numerous proposals over the years regarding their exact origin and systematic position. Though it was concluded early on in pterosaur research history that these animals represented a group of derived flying reptiles, their exact origination remained mysterious for a long time and is still somewhat controversial. A rough consensus has now been reached that pterosaurs are derived archosaurs and are likely close relatives of the dinosaurs, united with them in the clade Ornithodira, though some still challenge this view. The anatomical evidence in support of this position close to Dinosauria is also admittedly fairly limited at present, largely owing to a lack of any clear-cut transitional ‘proto-pterosaur’ taxa (albeit that some fragmentary specimens have been suggested to represent exactly this). Differing hypotheses have also recently been put forward as to the exact interrelationships between the pterosaurs and other non-dinosaurian and dinosaurian ornithodirans. Here the previous hypotheses of where pterosaurs fit into the reptilian lineage and the anatomical evidence in support of the current hypotheses are reviewed. Results of new analyses are included that looked to test the origin and systematic position of the Pterosauria using an expanded version of a large anatomical dataset of archosaurs, within which several previously unconsidered early pterosaur taxa and a suit of new anatomical characters were considered. The analyses in this study support the close affinities between pterosaurs and dinosauriforms within Ornithodira; Pterosauria is recovered as the sister-taxon to Lagerpetidae. Such a result suggests that the clade Pterosauria belongs with Lagerpetidae as part of a broader Pterosauromorpha that then, with Dinosauriformes, falls within Ornithodira. The anatomical evidence in support of this position within Ornithodira is also discussed in detail.
... In contrast to dinosaurs, the notion of intracranial movements in another archosauromorph group, the pterosaurs is not so common. Except for the work of two authors, Arthaber (1919) and Wild (1978Wild ( , 1984, who regarded the Early Jurassic Dorygnathus banthensis and the Upper Triassic Eudimorphodon ranzii, respectively, as having streptostylic quadrate, and Bennett (1996a) who used the term ''metakinetic skull'' as a streptostylic character suggestive of archosauromorph nature of pterosaurs in his phylogenetic analysis, thus accepting Wild's (1978Wild's ( , 1984 concept for Eudimorphodon, this issue has largely been ignored. Hence, streptostyly, which refers to the anteroposterior rotation of the quadrate about the otic joint (for further information see Supporting Information), was the only form of kinesis ever suggested for pterosaurs. ...
... In contrast to dinosaurs, the notion of intracranial movements in another archosauromorph group, the pterosaurs is not so common. Except for the work of two authors, Arthaber (1919) and Wild (1978Wild ( , 1984, who regarded the Early Jurassic Dorygnathus banthensis and the Upper Triassic Eudimorphodon ranzii, respectively, as having streptostylic quadrate, and Bennett (1996a) who used the term ''metakinetic skull'' as a streptostylic character suggestive of archosauromorph nature of pterosaurs in his phylogenetic analysis, thus accepting Wild's (1978Wild's ( , 1984 concept for Eudimorphodon, this issue has largely been ignored. Hence, streptostyly, which refers to the anteroposterior rotation of the quadrate about the otic joint (for further information see Supporting Information), was the only form of kinesis ever suggested for pterosaurs. ...
Based on comparative anatomical, morphological, and phylogenetic considerations the potential of pterosaurs for cranial kinesis is assessed. Our investigation shows that whereas skeletally mature derived pterodactyloids have completely fused, rigid and doubtlessly akinetic skulls, skeletally immature derived pterodactyloids and more basal pterosaurs possess key features in the morphology of their otic and basal joints that are suggestive of cranial kinesis, namely streptostyly. In addition, pterosaurs exhibit an evolutionarily informative trend in the degree of cranial ossification, where it is low in most nonpterodactyloids (here named bifenestratans), intermediate in Rhamphorhynchus and Archaeopterodactyloidea, and high in derived pterodactyloids. Incomplete fusion could also indicate loose connections between skull elements. However, another crucial anatomical requirement of a kinetic skull, the permissive kinematic linkage is absent in all pterosaurian taxa. The fact, that the presence of permissive kinematic linkages in the skull is also a prerequisite of all types of cranial kinesis, provides hard evidence that all members of Pterosauria had akinetic skulls. Thus, the presence of the morphological attributes indicative of intracranial movements in some pterosaurs must be explained on grounds other than real potential for cranial kinesis. It could either be of mechanical or ontogenetic importance, or both. Alternatively, it might be considered as the morphological remnant of a real, kinetic skull possessed by the diapsid ancestors of pterosaurs.
... Among early pterosaurs, the most complete specimens are from deposits of Norian age in northern Italy, and are represented by the relatively advanced genus Eudi111orp/10do11 as well as such primitive forms as Petei11osa11rus and Preondacty/11s (Zambelli 1973 ;Wild 1978Wild , 1983Wild , 1984. Fragmentary pterosaurian material, including isolated teeth referrable to E11dim017Jlwdo11?, have also been reported from North America in the Late Triassic Dockum (Murry 1986) and possibly in the Chinle Formation as well (Jacobs & Murry 1980). ...
A diverse assemblage of fossil vertebrates has been discovered in the Fleming Fjord Formation (Malmros Klint and Ørsted Dal Members) in East Greenland between latitudes 71°15'N and 71°50'N. The fauna includes several species of mammals as well as prosauropod (Plateosaurus) and theropod dinosaurs, turtles (cf. Proganochelys), pterosaurs, aetosaurs (Aetosaurus ferratus, Paratypothorax andressi), labyrinthodont amphibians (Gerrothorax, Cyclotosaurus and possibly other taxa) and fishes (including sharks, actinopterygians, coelacanths and lungfish). The association of the genera Aetosaurus, Plateosaurus, Proganochelys, Cyclotosaurus and Gerrothorax is shared with well known European Norian faunas, and confirms the paleogeographic proximity of Greenland and Europe during Late Triassic time. On this evidence, the Ørsted Dal Member may be estimated to be at least as old as mid-Norian, but a comparable age estimate for the underlying Malmros Klint Member cannot be made on the basis of the fauna as presently known. The Malmros Klint Member is characterized by composite cyclicity with four orders of cycles involving silt-rich, ephemeral lake or playa-mudflat systems, loess beds, wave-reworked sand flats, flat pebble conglomerates and paleosols. The rhythmicity and thickness ratios of the beds are evidence that depositional conditions were controlled by Milankovitch cycles, with climatic conditions varying from humid, to dry with seasonal rainfall, to arid. Cyclical sedimentary conditions and climatic fluctuations appear to have continued during the subsequent deposition of the overlying Ørsted Dal Member.
... The clade Pterosauria is nested within Archosauria (Sereno 1991;Nesbitt 2011;Fig. 1), which also includes crocodilians, dinosaurs, both extinct and extant birds, and Prolacertiformes, which have been hypothesized as close pterosaur relatives (Wild 1984;Bennett 1996). Pterosaurs are often hypothesized to be the sister taxon to the Dinosauromorpha (Brochu 2001;Nesbitt 2011; but for alternative phylogenetic hypotheses see Bennett 1996 andPeters 2000). ...
Pterosaurs have fascinated scientists and nonscientists alike for over 200 years, as one of the three known clades of vertebrates to have evolved flapping flight. The smallest pterosaurs were comparable in size to the smallest extant birds and bats, but the largest pterosaurs were vastly larger than any extant flier. This immense size range, coupled with poor preservation and adaptations for flight unknown in extant vertebrates, have made interpretations of pterosaur flight problematic and often contentious. Here we review the anatomical, evolutionary, and phylogenetic history of pterosaurs, as well as the views, perspectives, and biases regarding their interpretation. In recent years, three areas of pterosaur biology have faced challenges and made advances: structure of the wing membrane, function of the pteroid, body size and mass estimates, as well as flight mechanics and aerodynamics. Comparative anatomical and fossil study, simulated bone loading, and aerodynamic modeling have all proved successful in furthering our understanding of pterosaur flight. We agree with previous authors that pterosaurs should be studied as pterosaurs, a diverse but phylogenetically, anatomically, and mechanically constrained clade that can offer new insights into the diversity of vertebrate flight.
... The earliest known pterosaurs date from the Triassic and are consistent with Permian origins of flight, whereas pterosaur gigantism (e.g. Quetzalcoatlus) is confined to the Cretaceous (Wild, 1984;Wellnhofer, 1991). Most recently, the earliest fossils of microbats have been dated at 50 million years before the present (MYBP) and demonstrate seemingly modern morphology, whereas bat origins may be placed either within the early Paleocene or late Cretaceous (Jepsen, 1970;Altringham, 1996). ...
Uniformitarian approaches to the evolution of terrestrial locomotor physiology and animal flight performance have generally presupposed the constancy of atmospheric composition. Recent geophysical data as well as theoretical models suggest that, to the contrary, both oxygen and carbon dioxide concentrations have changed dramatically during defining periods of metazoan evolution. Hyperoxia in the late Paleozoic atmosphere may have physiologically enhanced the initial evolution of tetrapod locomotor energetics; a concurrently hyperdense atmosphere would have augmented aerodynamic force production in early flying insects. Multiple historical origins of vertebrate flight also correlate temporally with geological periods of increased oxygen concentration and atmospheric density. Arthropod as well as amphibian gigantism appear to have been facilitated by a hyperoxic Carboniferous atmosphere and were subsequently eliminated by a late Permian transition to hypoxia. For extant organisms, the transient, chronic and ontogenetic effects of exposure to hyperoxic gas mixtures are poorly understood relative to contemporary understanding of the physiology of oxygen deprivation. Experimentally, the biomechanical and physiological effects of hyperoxia on animal flight performance can be decoupled through the use of gas mixtures that vary in density and oxygen concentration. Such manipulations permit both paleophysiological simulation of ancestral locomotor performance and an analysis of maximal flight capacity in extant forms.
There are three known vertebrate groups whose representatives can actively fly: birds, bats, and pterosaurs. Among them, birds are of greatest interest for biologists and engineers. It is the flight of birds that serves as a reference basis for other groups in the studyi or reconstruction the flight of vertebrates. However, whereas the aerodynamic principles are common for all groups due to the environmental uniformity, the biomechanical means of flying depend on the morphological wing features of each of these groups due to their individual evolutionary prehistory. In addition, we can directly observe the flight of birds and bats and compare our assumptions with the actual state, while the study of pterosaurs does not provide this opportunity and allows reconstruction of the flight principles of this group only on the basis of paleontological data on the morphological features of their wing and evolution.
Traditionally, pterosaurs have been included within the Archosauriformes and many contemporary workers consider the Pterosauria the sister group to Lagosuchus, Scleromochlus and the Dinosauria. New analyses cast doubts on those relationships because nearly all presumed archosauriform or ornithodire "synapomorphies" are either not present within the Pterosauria or are also present within certain prolacertiform taxa. Recent examinations of the holotypes of Cosesaurus aviceps, Longisquama insignis and Sharovipteryx mirabilis suggest that many characters may be interpreted differently than previously reported. Results of several subsequent cladistic analyses suggest that these three "enigmatic" prolacertiforms, along with the newly described Langobardisaurus, are sister taxa to the Pterosauria based on a suite of newly identified synapomorphies.
Our knowledge of extinct animals depends almost entirely upon the study of fossils. This richly illustrated book clothes the skeletons of dinosaurs and other Mesozoic reptiles with flesh, and shows how these fascinating animals evolved and probably lived. Expert author John L. Cloudsley-Thompson provides an interesting synthesis of current views on their ecology, physiology and behaviour, and outlines the various hypotheses that have been proposed to explain their extinction. Numerous beautiful drawings of the animals and their environment illustrate this exciting monograph.
New observations about the osteology and the systematic position of Preondactylus buffarinii Wild 1984b, are based on a reexamination of the holotype (1770MFSN). The carpus and metacarpus of this specimen are described in detail after further preparation. New measurements for the wing metacarpal, first wing phalanx and tibia are presented, allowing new postcranial bone length ratios to be calculated. Similarities of P. buffarinii to Peteinosaurus zambellii are emphasized; its condition of most primitive pterosaur is open to discussion and its diagnosis is emended.
Three theories about the origin of flight in pterosaurs have been proposed: 1) the arboreal parachuting theory (passive falling from trees leading to gliding and eventually to powered flight); 2) the cursorial theory (bipedal running and leaping leading directly to powered flight); and 3) the arboreal leaping theory (active leaping between branches and trees leading to powered flight). The available evidence as to the functional morphology of pterosaurs, and in particular their hindlimb, is reviewed and used to test the three theories. Pterosaurs were well suited for arboreality and their hindlimb morphology argues against cursoriality, but supports an arboreal leaping lifestyle for early pterosaurs or their immediate ancestors.
Ősi, A. 2011: Feeding-related characters in basal pterosaurs: implications for jaw mechanism, dental function and diet. Lethaia, Vol. 44, pp. 136–152.A comparative study of various feeding-related features in basal pterosaurs reveals a significant change in feeding strategies during the early evolutionary history of the group. These features are related to the skull architecture (e.g. quadrate morphology and orientation, jaw joint), dentition (e.g. crown morphology, wear patterns), reconstructed adductor musculature and post-cranium. The most basal pterosaurs (Preondactylus, dimorphodontids and anurognathids) were small-bodied animals with a wingspan no greater than 1.5 m, a relatively short, lightly constructed skull, straight mandibles with a large gape, sharply pointed teeth and well-developed external adductors. The absence of extended tooth wear excludes complex oral food processing and indicates that jaw closure was simply orthal. Features of these basal-most forms indicate a predominantly insectivorous diet. Among stratigraphically older but more derived forms (Eudimorphodon, Carniadactylus, Caviramus) complex, multicuspid teeth allowed the consumption of a wider variety of prey via a more effective form of food processing. This is supported by heavy dental wear in all forms with multicuspid teeth. Typical piscivorous forms occurred no earlier than the Early Jurassic, and are characterized by widely spaced, enlarged procumbent teeth forming a fish grab and an anteriorly inclined quadrate that permitted only a relatively small gape. In addition, the skull became more elongate and body size increased. Besides the dominance of piscivory, dental morphology and the scarcity of tooth wear reflect accidental dental occlusion that could have been caused by the capturing or seasonal consumption of harder food items. □Basal pterosaurs, heterodonty, dental wear, insectivory, piscivory.
In recent years the hypothesis that pterosaurs were the major sister-group of dinosaurs and a closely-linked hypothesis that pterosaurs evolved flight from the ground up have gained general acceptance. A cladistic analysis of the Archosauromorpha using characters presented by previous workers results in a single most parsimonious tree with the Pterosauria as the major sister-group of the Dinosauria. However, that sister-group relationship is supported only by a suite of hindlimb characters that are correlated with bipedal digitigrade locomotion in dinosaurs. In pterosaurs the characters have been interpreted as correlates of bipedal cursorial locomotion, arboreal leaping, or involvement of the hindlimb in the wing. The homology of those characters in dinosaurs and pterosaurs cannot be supported. Reanalysis of the data after exclusion of those hindlimb characters results in most parsimonious trees with the Pterosauria as the sister-group of the Erythrosuchidae + Proterochampsidae +Euparkeria + Archosauria, in that order. This sister-group relationship is supported by a diverse assemblage of functionally independent skeletal characters from all regions of the skeleton. The results of the analysis cast doubt on the hypothesis that pterosaurs evolved flight from the ground up.
Two teeth collected from the Upper Triasssic Chinle Formation of northeastern Arizona are described here and named Kraterokheirodon colberti gen. et sp. nov. These teeth are novel in having an occlusal ridge with six cusps and a posterior shelf lacking dentine. Evidence for thecodont implantation of the root suggests amniote affinities for these teeth. They do not match any teeth known for basal vertebrates or basal tetrapods. Although the teeth display some affinities with "traversodont" cynodonts, there are significant differences that preclude a referral to this group. These teeth most probably represent an unknown tetrapod clade and document the presence of a large amniote previ-ously unknown from Late Triassic terrestrial faunas. Résumé : Deux dents provenant de la Formation de Chinle du Trias supérieur du nord-est de l'Arizona sont décrites et attribuées à Kraterokheirodon colberti gen. et sp. nov. Ces dents sont uniques en cela qu'elles présentent une crête occlusale dotée de six cuspides et un plan de morsure postérieur exempt de dentine. Des observations à l'appui d'une implantation thécodonte de la racine laissent croire à des affinités avec les amniotes. Ces dents diffèrent de toute autre dent attribuable à des vertébrés primitifs ou des tétrapodes primitifs. Bien qu'elles présentent certaines affinités avec les cynodontes « traversodontes », d'importantes différences écartent leur affectation à ce groupe. Ces dents représentent vraisemblablement un clade de tétrapodes inconnu et témoignent de la présence d'un grand amniote, jusqu'ici inconnu, dans les faunes terrestres du Trias tardif.
Previous cladistic studies of pterosaur relationships suffer from restricted numbers of taxa and characters, incomplete data sets and absence of information on characters, tree structure and the robustness of trees. Parsimony analysis of a new character data set (60 characters, 20 terminal taxa, 93.75% complete) yielded six trees. In the strict consensus tree Preondactylus is the most basal taxon followed, stepwise, by the Dimorphodontidae and the Anurognathidae. Beyond this basal group, more derived pterosaurs (Campylognathoididae (Rhamphorhynchidae + Pterodactyloidea)) share a suite of characters principally associated with elongation of the rostrum. The Pterodactyloidea consists of four major clades. The Ornithocheiroidea is the most basal taxon consisting, stepwise, of Istiodactylus, the Ornithocheiridae, Nyctosaurus and the Pteranodontidae. The remaining taxa, Ctenochasmatoidea, Dsungaripteroidea and Azhdarchoidea, are weakly united in a clade of non-ornithocheiroid pterodactyloids, but their inter-relationships are difficult to resolve. Cycnorhamphus is the basal-most ctenochasmatoid, while the remaining taxa (Pterodactylus, Lonchodectidae, Ctenochasmatidae) form an unresolved trichotomy. The Dsungaripteroidea (Germanodactylus + Dsungaripteridae) is strongly supported by features of the skull and dentition. The Azhdarchoidea (Tapejara [Tupuxuara + Azhdarchidae]) is united by cranial characters such as elevation of the antorbital region, and relative shortening of the wing finger. The pattern of pterosaur evolution suggested by the results of this analysis is broadly similar to traditional ideas, but has greater resolution, more complexity and reveals several previously unrecognized 'events'.
Recent geophysical analyses suggest the presence of a late Paleozoic oxygen pulse beginning in the late Devonian and continuing through to the late Carboniferous. During this period, plant terrestrialization and global carbon deposition resulted in a dramatic increase in atmospheric oxygen levels, ultimately yielding concentrations potentially as high as 35% relative to the contemporary value of 21%. Such hyperoxia of the late Paleozoic atmosphere may have physiologically facilitated the initial evolution of insect flight metabolism. Widespread gigantism in late Paleozoic insects and other arthropods is also consistent with enhanced oxygen flux within diffusion-limited tracheal systems. Because total atmospheric pressure increases with increased oxygen partial pressure, concurrently hyperdense conditions would have augmented aerodynamic force production in early forms of flying insects. By the late Permian, evolution of decompositional microbial and fungal communities, together with disequilibrium in rates of carbon deposition, gradually reduced oxygen concentrations to values possibly as low as 15%. The disappearance of giant insects by the end of the Permian is consistent with extinction of these taxa for reasons of asphyxiation on a geological time scale. As with winged insects, the multiple historical origins of vertebrate flight in the late Jurassic and Cretaceous correlate temporally with periods of elevated atmospheric oxygen. Much discussion of flight performance in Archaeopteryx assumes a contemporary atmospheric composition. Elevated oxygen levels in the mid- to late Mesozoic would, however, have facilitated aerodynamic force production and enhanced muscle power output for ancestral birds, as well as for precursors to bats and pterosaurs.
Debate over the origin and evolution of vertebrates has occupied biologists and palaeontologists alike for centuries. This debate has been refined by molecular phylogenetics, which has resolved the place of vertebrates among their invertebrate chordate relatives, and that of chordates among their deuterostome relatives. The origin of vertebrates is characterized by wide-ranging genomic, embryologic and phenotypic evolutionary change. Analyses based on living lineages suggest dramatic shifts in the tempo of evolutionary change at the origin of vertebrates and gnathostomes, coincident with whole-genome duplication events. However, the enriched perspective provided by the fossil record demonstrates that these apparent bursts of anatomical evolution and taxic richness are an artefact of the extinction of phylogenetic intermediates whose fossil remains evidence the gradual assembly of crown gnathostome characters in particular. A more refined understanding of the timing, tempo and mode of early vertebrate evolution rests with: (1) better genome assemblies for living cyclostomes; (2) a better understanding of the anatomical characteristics of key fossil groups, especially the anaspids, thelodonts, galeaspids and pituriaspids; (3) tests of the monophyly of traditional groups; and (4) the application of divergence time methods that integrate not just molecular data from living species, but also morphological data and extinct species. The resulting framework will provide for rigorous tests of rates of character evolution and diversification, and of hypotheses of long-term trends in ecological evolution that themselves suffer for lack of quantitative functional tests. The fossil record has been silent on the nature of the transition from jawless vertebrates to the jawed vertebrates that have dominated communities since the middle Palaeozoic. Elucidation of this most formative of episodes likely rests with the overhaul of early vertebrate systematics that we propose, but perhaps more fundamentally with fossil grades that await discovery.
Tibiotarsi ofDsungaripterus?brancai (Reck) (Upper Jurassic, East Africa),D. weii Young (Lower Cretaceous, China) andPuntanipterus globosus Bonaparte & Sanchez (Lower Cretaceous, South America) have a bird-like distal end with attachment areas for a transverse
ligament anteriorly, lateral and medial ligamentous prominences, and an anteroposteriorly, expanded pulley-like articular
surface. The M. extensor digitorum longus flexed the ankle and probably also extended the digits as in living birds and mammals.
A separate tendinous slip for digit I probably passed from the M. flexor digitorum longus in a groove posteroventral to the
medial ligamentous prominence.
Die Tibiotarsi vonDsungaripterus?brancai (Reck) (Oberjura, Ostafrika),D. weii Young (Unterkreide, China) undPuntanipterus globosus Bonaparte & Sánchez (Unterkreide, Südamerika) besitzen ein vogelähnliches Distalende mit folgenden Besonderheiten: an der
Vorderseite Anheftungsflächen für ein transversales Ligament, laterale und mediale Ligamenthöcker und eine anteroposterior
ausgedehnte, rollenartige Gelenkfläche. Der M. extensor digitorum longus beugte das Fußgelenk und streckte wahrscheinlich
auch die Zehen wie bei lebenden Vögeln und Säugetieren. Ein getrennter Sehnenstrang für die erste Zehe verlief wahrscheinlich
vom M. flexor digitorum longus in einer Rinne von posteroventral zum mittleren Ligamenthöcker.
- R Owen
- R. Owen