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New remains of the pterosaur Dimorphodon (Pterosauria: Rhamphorhynchoidea) and the terrestrial ability of early pterosaurs

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... Pterosaurs were the first vertebrates to fly, and many workers have reported on wing structure and aerodynamics. Relatively fewer workers have reported on trackway production and terrestrial locomotion (Stokes, 1957; Padian, 1983a Padian, , b, 1984 Padian, , 1985 Padian, , 2003 Padian and Olsen, 1984; Padian and Rayner, 1993; Bennett, 1990 Bennett, , 1997a Logue, 1994; Lockley et al., 1995 Lockley et al., , 1997 Mazin et al., 1995; Unwin, 1987 Unwin, , 1988 Unwin, , 1989 Unwin, , 1997 Hwang et al., 2002; Wellnhofer, 1975 Wellnhofer, , 1978 Wellnhofer, , 1988 Wellnhofer, , 1991 Chatterjee and Templin, 2004). Even fewer have compared pterosaur pedal skeletons (Wild, 1978; Wellnhofer, 1974 Wellnhofer, , 1978 Wellnhofer, , 1991 Unwin, 1989). ...
... long tail associated with a pterodactyloid skull (Lü et al., 2009; Wang et al., 2009). With regard to terrestrial locomotion in pterosaurs, most workers have discussed the angles formed by the pelvis and acetabulum (Wellnhofer, 1975; Padian, 1983a, b; Unwin, 1988; Bennett, 1997a, b; Chatterjee and Templin, 2004), the knee joint (Padian, 1983a, b; Bennett, 1997a, b) and the ankle hinge (Padian, 1983a, b; Bennett, 1997a, b), but relatively little has been reported on comparative pterosaur pedal morphology, mechanics and evolution (Peters, 2000a, b). Previous studies have matched hominid, early tetrapod and early amniote trackmakers to ichnites (Raichlen et al., 2010; Niedzwiedzki et al., 2010; Voigt, Berman and Henrici, 2007). ...
... sp. (GSM 1546; Unwin, 1988) an early Jurassic proto-anurognathid. (Continued on next page) to an inverted hanging posture. ...
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A previously unnoticed geometric pattern is present in the extremities of all tetrapods. Sets of straight and typically uninterrupted hinge lines pass through neighboring interphalangeal joints and across ungual tips. Four sets of these lines appear in basal polydactyl tetrapods, two medial sets, a transverse set and a lateral set. The two medial sets merge in primitive pentadactyl tetrapods. The resulting three line sets persist in later taxa, even when digits shrink and disappear. Primitively and typically the lines in each set are more or less parallel, but lines may converge, merge and shift as phalanges disappear or phalangeal patterns change. Confirming this geometric pattern, complex interphalangeal joint surfaces typically align with hinge lines and pad divisions parallel them. In addition, unguals rarely cross extensions of hinge lines and longer unguals may divert medially or laterally rather than cross them. Exceptions occur most commonly on ungual II. Line sets may exist because phalanges appear to flex and extend most efficiently in unison. Hinge line patterns appear to identify clades so they may, to a limited extent, be used taxonomically. Hinge lines also have predictive value in that missing phalanges, including unguals, can be reconstructed with confidence using hinge lines as size guides. Correct digit spread and metapodial configuration can also be determined in extinct taxa by seeking the appearance of continuous interphalangeal hinge lines in tested reconstructions.
... The most common and consensual current conclusion suggests that non-pterodactyloid pterosaurs were bad (or no) walkers, but probably good climbers. Anatomical arguments coupled with the lack of non-pterodactyloid tracks reinforce this interpretation (Unwin, 1987(Unwin, , 1988(Unwin, , 1989(Unwin, , 1999(Unwin, , 2006Unwin and Bakhurina, 1994;Bennett, 1997a). Thus, pterodactyloids and non-pterodactyloid pterosaurs could have occupied different environments, with different behaviours, non-pterodactyloids never (or rarely) landing on the ground. ...
... During the debate of the years 1970-90 about the stance and gait of grounded pterosaurs, palaeontologists were divided about the bipedal and quadrupedal hypotheses (Logue, 1977(Logue, , 1994Padian, 1983aPadian, , 1983bPadian and Olsen, 1984;Wellnhofer, 1988;Unwin, 1988Unwin, , 1989. Then, new ichnological evidence was reported, which definitely demonstrated the quadrupedal stance and gait of walking pterodactyloid pterosaurs, that led to the current consensus of semi erect quadrupedal pterodactyloids (Logue, 1977(Logue, , 1994Mazin et al., 1995Mazin et al., , 1997Lockley et al., 1995;Unwin, 1996aUnwin, , 1996bUnwin, , 1999Bennett, 1997bBennett, , 1997aClark et al., 1998). ...
... Two arguments were used to discuss these capabilities. First, several features seem to make the ''rhamphorhynchoids'' best climbers than walkers, with more arboreal than terrestrial behaviours, which should explain the lack of trackways (Unwin, 1987(Unwin, , 1988(Unwin, , 1989(Unwin, , 1996b(Unwin, , 1999(Unwin, , 2006Unwin and Bakhurina, 1994;Bennett, 1997a). A second group of arguments considers the non-pterodactyloids as digitigrade bird-like bipeds, even good runners, with limited motion of the forelimbs which cannot reach the substrate (Padian, 1983a(Padian, , 1983b(Padian, , 1985(Padian, , 2003(Padian, , 2008a(Padian, , 2008b. ...
Article
New discoveries on the ichnological site known as “the Pterosaur Beach of Crayssac” (lower Tithonian, Upper Jurassic; south-western France) answer the question of terrestrial capabilities of non-pterodactyloid pterosaurs. If the terrestrial type of locomotion of pterodactyloid pterosaurs has been solved from ichnological evidence for more than twenty years, no tracks and trackways referable to non-pterodactyloid pterosaurs have ever been described. Thus, the debate on terrestrial capabilities of these non-pterodactyloids was based on morpho-functional studies, with the main conclusion that those pterosaurs were arboreal dwellers and bad walkers. Six trackways referable to three non-pterodactyloid new ichnotaxa, maybe closely related to Rhamphorhynchidae, are described in this work. Their study leads to the conclusion that grounded non-pterodatyloids, at least during the Late Jurassic, were quadrupedal with digitigrade manus and plantigrade to digitigrade pes. They were clearly good walkers, even if hindlimbs are supposed to be hampered by the uropatagium, what could have constrained the terrestrial agility of these animals. Thus, from ichnological evidence and contrary to the current hypotheses, non-pterodactyloid pterosaurs seem to have been good walkers even though their trackways are very rare or unidentified to date. This rarity could be due to behaviour rather than to functional capacities, many non-pterodactyloids being considered both littoral fishers and arboreal or cliff dwellers. However, the concept of non-pterodactyloid “good climbers and bad walkers” has to be modified to “good climbers and rare walkers”, unless many non-pterodactyloid ichnites have yet to be discovered.
... Much ink has been used in the discussion of the orientation of the pterosaur acetabulum with hypotheses ranging from lateral (Wellnhofer, 1975a(Wellnhofer, , 1978Bennett, 2001a:100), lateroventral (Padian, 1983b), laterodorsal (Wellnhofer and Vahldiek, 1986;Unwin, 1987;Wellnhofer, 1988:4), anterodorsal (Unwin, 1988), posterolateral (Bennett, 1990:80;Kellner and Tomida, 2000;Bennett, 2001a:97,99-100), to laterodorsoposterior (Molnar, 1987;Wellnhofer, 1988:3,9;Bennett, 1990;2001a:99). Considering that the point of greatest depth is positioned dorsoanteriorly within the acetabulum of TMM 41954-57, it would be most defensible that the acetabulum of Q. lawsoni is oriented ventroposteriorly. ...
... The pterosaur tarsus consists of four or (more rarely) five elements: two proximal series tarsals and two to three distal series tarsals (Wellnhofer, 1970(Wellnhofer, , 1975b(Wellnhofer, , 1978(Wellnhofer, , 1991bPadian, 2017). The proximal tarsals (astragalus and calcaneum) fuse to the distal end of the tibia early in ontogeny to form the distal condyles of the tibiotarsus (Seeley, 1901;Wellnhofer, 1978;Padian, 1983a;Unwin, 1988;Bennett, 1993;Dalla Vecchia, 2003b). When they are unfused, they are usually a pair of indistinct disk-or lozenge-shaped elements found in juvenile pterosaurs preserved in laminated deposits (e.g., Solnhofen Limestone). ...
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Quetzalcoatlus is the largest flying organism ever known and one of the most familiar pterosaurs to the public. Despite a half century of interest, it remains very incompletely described. This shortfall is addressed here through a full morphological description of Quetzalcoatlus and the other pterosaur material of Big Bend National Park, Texas. The first reported material was described and named Quetzalcoatlus northropi by Douglas Lawson in 1975, but in two separate publications. A ruling by the International Commission of Zoological Nomenclature was required for the name to be made available. Review of the pterosaur fauna of the Park recovers three valid species of azhdarchid pterosaurs in the latest Cretaceous Period Javelina and Black Peaks formations. The size and occurrence of these species are correlated with depositional environment. The holotype of the giant Quetzalcoatlus northropi and six other giant specimens referred to it occur in stream-channel deposits, including the youngest reported pterosaur. The vast majority of specimens (200+) are from large pterosaurs found in the abandoned channel-lake deposits at Pterodactyl Ridge; they form a diagnosable natural group erected as the new species Quetzalcoatlus lawsoni. A moderate-sized partial skull and cervical series also found in the abandoned channel-lake deposits at Pterodactyl Ridge, but lower in the section, is distinct from both species and is erected as Wellnhopterus brevirostris, gen. et sp. nov. Overbank flood-plain facies preserve another eleven specimens of extreme size variation, including small azhdarchids. The Big Bend pterosaur fauna provides the greatest known sample of azhdarchid pterosaurs and three-dimensional pterosaur morphology.
... Quest'ultimo continua ad essere una creatura fondamentale nella ricerca sugli pterosauri, per esempio per studi sulla postura (Padian, 1983b;Unwin, 1988a;Bennett, 1997;Clark, et al. 1998) e sulle relazioni tra pterosauri e altri rettili (Nesbitt and Hone, 2010). I Dimorphodontidae possono essere descritti come frutto di una radiazione evolutiva iniziale di pterosauri con grandi teste, probabilmente ben adattati per scalare gli alberi. ...
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A new and articulated specimen of a pterosaur wing including upper arm, forearm, parts of the carpus and metacarpus, and a wing phalanx from Maastrichtian phosphatic deposits of Morocco are assigned to Tethydraco cf. regalis Longrich et al., 2018. The specimen comes from the village of Ouled Abdoun, close to the Oued Zem basin and its phosphatic mines (Morocco). The fossil is part of the collection of the Université Hassan II of Casablanca (ID Number FSAC CP 251). In the first part, the thesis presents a synthetic introduction about the morphology, anatomy, physiology and evolution of pterosaurs in order to offer a comprehensive framework on this fascinating group of extinct flying tetrapods. The main goal of this work is the taxonomic identification of the specimen, principally by morphological and morphometric/statistic analysis, based on the comparison with the most similar pterosaurs of the same epoch. Aspect of the humerus morphology and dimensional ratios of the wing elements suggest that T. cf. regalis is an azhdarchid rather than pteranodontid, as originally proposed. A high abundance of azhdarchid remains in the open marine setting of the Moroccan phosphates casts doubt on suggestions that Azhdarchidae were largely terrestrial pterosaurs.
... the proximal articulation is expanded and the portion of the bone that might have been interpreted as the deltopectoral crest is triangular. Based on the anatomy of Dimorphodon humeri (e.g., Wellnhofer 1978, Padian 1983, Unwin 1988, the shaft is curved, differing from the straight bone reported from Antarctica. In Dimorphodon, the deltopectoral crest is longer, does not extend as deep on the shaft and is not triangular. ...
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Fossil vertebrates from Antarctica are considerably rare, hampering our understanding of the evolutionary history of the biota from that continent. For several austral summers, the PALEOANTAR project has been carrying out fieldwork in the Antarctic Peninsula in search for fossils, particularly Cretaceous vertebrates. Among the specimens recovered so far are two bones referable to Pterosauria, more specifically to the Pterodacyloidea, the first volant reptiles from Antarctica to be fully described. MN 7800-V (part and counterpart) was recovered from a moraine at the Abernathy Flats (Santa Marta Formation, Lachman Crags Member, Santonian-Campanian) on James Ross Island. It is interpreted as the distal articulation of a first phalanx of the wing finger, representing an animal with an estimated wingspan between 3 and 4 m. The second specimen (MN 7801-V) comes from Vega Island (Snow Hill Island Formation, Maastrichtian) and is identified as a wing metacarpal IV of an animal with an estimated wingspan from 4 to 5 m. These occurrences show that pterodactyloids inhabited the Antarctic Peninsula at least during the Upper Cretaceous and demonstrate that large pterosaurs were widespread through all parts of the planet during that period.
... C. hanseni differs from D. macronyx in numerous ways (Fig. 4b,c). In D. macronyx: (1) the jugal process of the maxilla ends anterior to the posterior margin of the antorbital fenestra, and the suture between the maxilla and jugal is vertical and sigmoid 16 ; (2) the jugal does not contribute to the antorbital fossa 16,24,33 ; (3) the orbit faces laterally and deeply notches the jugal 16 ; (4) the orbit shape is an inverted tear drop 16 ; (5) the frontoparietal is more elongated than in C. hanseni 16 ; (6) the nasal is comparatively shorter and triangular, with an anteriorly directed premaxillary process 16 ; (7) the surangular dorsal process is a small, blunt point (BMNH 43486); and (8) there is no longitudinal furrow along the posterior margin of the wing phalanges 34 . ...
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Pterosaurs are the oldest known powered flying vertebrates. Originating in the Late Triassic, they thrived to the end of the Cretaceous. Triassic pterosaurs are extraordinarily rare and all but one specimen come from marine deposits in the Alps. A new comparatively large (wing span >150 cm) pterosaur, Caelestiventus hanseni gen. et sp. nov., from Upper Triassic desert deposits of western North America preserves delicate structural and pneumatic details not previously known in early pterosaurs, and allows a reinterpretation of crushed Triassic specimens. It shows that the earliest pterosaurs were geographically widely distributed and ecologically diverse, even living in harsh desert environments. It is the only record of desert-dwelling non-pterodactyloid pterosaurs and predates all known desert pterosaurs by more than 65 Myr. A phylogenetic analysis shows it is closely allied with Dimorphodon macronyx from the Early Jurassic of Britain.
... The presence of sesamoid bones at the dorsal side of manual unguals have been reported in many basal pterosaurs (e.g., Wild, 1978;Wild, 1994;Padian, 1983;Padian, 2008;Dalla Vecchia, 2009). These ossifications were probably connected with the extensor digitorum brevis (Bennett, 2008), whose function has been linked with grasping capabilities, climbing and terrestrial locomotion (Unwin, 1988;Bennett, 1997;Witton, 2015). The presence of a sesamoid is also observed in at least one pedal phalanx of the holotype (IVPP V 16047) of Kunpengopterus sinensis. ...
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The Wukongopteridae compose a non-pterodactyloid clade of pterosaurs that are the most abundant flying reptiles in the deposits of the Middle-Late Jurassic Yanliao Biota. Until now, five species of three genera and two additional unnamed specimens have been described. Here we report on a new material, IVPP V 23674, that can be referred to the wukongopterid Kunpengopterus sinensis due to several features such as a comparably short nasoantorbital fenestra, the dorsally rising posterodorsal margin of the ischium, and the very short first pedal phalanx of digit V relative to metatarsal IV. IVPP V 23674 provides the first view of a wukongopterid palate, which differs from all other pterosaurs by having a very large postpalatine fenestra and laterally compressed choanae, indicating that the evolution of the pterosaur palate was more complex than previously thought. Sesamoid bones at the dorsal side of manual unguals are present and are reported for the first time in a wukongopterid suggesting an arboreal life-style for these pterosaurs.
... Trackways of pterosaurs have previously aroused much controversy. One reason is the mode of terrestrial locomotion, since according to some authors ( Cuvier, 1801Cuvier, , 1809Padian, 1983;Paul, 1987) they were bipedal, while others ( Soemmerring, 1812;Unwin, 1987Unwin, , 1988Wellnhofer, 1988Wellnhofer, , 1991Unwin, 1999, 2001;Chatterjee and Templin, 2004) consider them quadrupeds, not to mention those who think gait varies according to size, as in the case of Bennett (1997), who supports bipedalism only for major pterodactyloides. Therefore there are doubts about the trackmakers of some Pteraichnus tracks as famously, but incorrectly raised by Padian and Olsen (1984) who attributed them to crocodiles. ...
Article
Cretaceous pterosaurs tracksites are very rare worldwide. Until now,only one African Cretaceous site withtracks of (Agadirichnus elegans and Pteraichnus) was known. This makes the discovery of a new outcrop in the Upper Cretaceous of Anza (Morocco) the third manifestation of this type of footprint in Africa, extending the existence of such traces from the Coniacian-Santonian to the Maastrichtian. The site contains only manus tracks, which can be explained as a result of erosion of pes prints. The lack of pes prints and the morphometric characteristics of the manus prints only allow us to relate these prints to Agadirichnus, Pteraichnus or maybe to a new ichnogenus. It is possible that the trackmakers are related to Ornithocheiroidea or Azhdarchoidea superfamilies whose fossil bones have been found from the Late Cretaceous in Morocco.
... The Rhamphorhynchoidea pterosaurs were broadly characterised by their long tails, which enabled dynamic stability and a considerable degree of maneuverability (Wellnhofer 1991;Witmer et al. 2003). In Rhamphorhynchoid digit V was longer than digit I; some authors have argued that pedal digit V controlled the uropatagium, and was therefore functionally implicated in pterosaur flight (Unwin 1988;Bakhurina and Unwin 1992). Broadly there are two functional paradigms of pterosaur flight: the first posits that the wing membrane incorporates the hindlimb with the forelimb (Wellnhofer 1991;Unwin and Bakhurina 1994;Unwin 1999;Unwin 2006), and the second asserts that the hindlimb does not contribute to flight, due to the absence of wing membrane attachment of the forelimb to the hindlimb (Padian 1983). ...
Article
Compositional data are those which contain only relative information. They are parts of some whole. In most cases they are recorded as closed data, i.e. data summing to a constant, such as 100% – whole-rock geochemical data being classic examples. Compositional data have important and particular properties that preclude the application of standard statistical techniques on such data in raw form. Standard techniques are designed to be used with data that are free to range from 21 to þ1. Compositional data are always positive and range only from 0 to 100, or any other constant, when given in closed form. If one component increases, others must, perforce, decrease, whether or not there is a genetic link between these components. This means that the results of standard statistical analysis of the relationships between raw components or parts in a compositional dataset are clouded by spurious effects. Although such analyses may give apparently interpretable results, they are, at best, approximations and need to be treated with considerable circumspection. The methods outlined in this volume are based on the premise that it is the relative variation of components which is of interest, rather than absolute variation. Log-ratios of components provide the natural means of studying compositional data. In this contribution the basic terms and operations are introduced using simple numerical examples to illustrate their computation and to familiarize the reader with their use.
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We reconstruct the proportions and possible motions of the skeleton of the giant azhdarchid pterosaur Quetzalcoatlus. The neck had substantial dorsoventral mobility, and the head and the neck could swing left and right through an arc of ca. 180°. In flight, it is most plausible that the hind limbs were drawn up bird-like, with the knee anterior to the acetabulum. In this position, an attachment of the wing membrane to the hind limb would have been useless. A straight-legged posterior extension of the hind limb, such as rotation of the hind limb into a fully ‘bat-like’ pose, was likely prevented by soft tissues of the hip joint. Given these difficulties, the traditional ‘broad-winged’ bat-like restoration is unrealistic. On the ground, Quetzalcoatlus, like other ornithodirans, had an erect stance and a parasagittal gait. Terrestrial locomotion was powered almost entirely by the hind limbs. The pace length would have been limited to the length of the glenoacetabular distance, except that Quetzalcoatlus (like other pterodactyloids) had a unique gait in which the forelimb was elevated out of the way of the hind limb from step to step. If the humerus were retracted 80° and adducted nearly to the body wall, the elbow and wrist may have been able to extend to effect a quadrupedal launch with assistance from the hind limbs, assuming sufficient long bone strength and sufficient extensor musculature at these forelimb joints. A bipedal launch using the hind limbs alone also appears plausible: despite the animal’s great size, the hind limb to torso length ratio is the greatest for all known pterosaurs.
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