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Close-up of bone structure in a bone fragment from the holotype of Hatzegopteryx thambema, showing the thin outer cortex (upper right) and the inner meshwork of bony trabeculae enclosing elongated alveoli. Scale bar 30 mm.  

Close-up of bone structure in a bone fragment from the holotype of Hatzegopteryx thambema, showing the thin outer cortex (upper right) and the inner meshwork of bony trabeculae enclosing elongated alveoli. Scale bar 30 mm.  

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Pterosaur remains from the Late Cretaceous of the Hateg Basin of western Romania were reported by Nopcsa as early as 1899. Recent discoveries from the Late Maastrichtian Densuş-Ciula Formation include the giant azhdarchid Hatzegopteryx thambema, the holotype of which, consisting of skull elements and a humerus from the Vǎlioara locality, is describ...

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... mentioned (Buffetaut et al. 2002), both the proximal part of the humerus and the skull bones of the type of H. thambema show a peculiar structure. Under a very thin outer cortex (which is usually no more than 1 mm in thickness), the bones consist of a dense meshwork of paper-thin bony tra- beculae which enclose relatively small empty spaces (Fig. 7). These alveoli are very numerous, closely packed and elongate, being usually a few millime- tres in width and up to more than 10 mm in length. This structure is rather reminiscent of expanded polystyrene, and probably resulted in a fairly rigid but light ...

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... The azhdarchids are one of the most successful Cretaceous pterosaur groups and include several large species with wingspans of approximately 9-11 m ( Table 1) (10)(11)(12)(13). Although their huge sizes have been lead debate about whether they were flightless (14)(15)(16), ...
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... The left jugal of TMM 41961-1.1 is the most completely preserved, but the main body of its right jugal has been largely destroyed. A jugal is also reported in the azhdarchid species H. thambema (Buffetaut et al., 2003), Z. linhaiensis (Cai and Wei, 1994), and A. bostobensis (CCMGE 41/11915) (Averianov, 2004). ...
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... In Volgadraco bogolubovi, only the diaphysis of the femur is preserved, and it is a large, hollow, thin-walled bone, with a bowed shaft (Averianov et al. 2008). Hatzegopteryx has a slightly bowed femur with a thin wall, the fourth trochanter lacks a marked tuberosity, and a small knob is located close to the proximal ridge, perhaps corresponding to the internal trochanter (Buffetaut et al. 2003). A curved femur is recognized also in the azhdarchoids Shenzhoupterus (Lü et al. 2008) and Huaxiapterus, where the femoral head is distinct and set on a narrow neck, angled from the shaft (Lü and Yuan 2005;Lü et al. 2006). ...
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... In azhdarchids, the deltopectoral crest is much longer and has subparallel proximal and distal margins for most of its length (Lawson, 1975: fig. 1b, c;Buffetaut et al., 2003: fig. 6 ZIN PH 74/43 is the largest proximal syncarpal known for the Pterosauria. ...
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The Campanian Beloe Ozero locality within the Rybushka Formation in Saratov Province, Russia, is one of the richest and most diverse Upper Cretaceous pterosaur localities in Europe. It produces identifiable remains of Pteranodontidae indet. and Azhdarchidae indet., as well as bones which can be attributed to either of these groups. The pteranodontid specimens from the Beloe Ozero locality described in this paper include a cervical III, distal scapula, hume-rus deltopectoral crest, proximal syncarpal, preaxial carpal and complete femur. Based on the femur and proximal syncarpal, the wingspan estimate for the Beloe Ozero pteranodontid varies from 5.2 to 6.5 m. Volgadraco bogolubovi, known from the neighbouring Shyrokii Karamysh locality of the same formation and attributed previously to the Azhdarchidae, is more likely pteranodontid than azhdarchid. The other putative records of the Pteranodontidae in the Late Cretaceous of North America, Europe and Asia are discussed. Pteranodontid pterosaurs had a much wider distribution on the northern continents in the Late Cretaceous than previously thought.
... Pteranodon, presumably the most famous pterosaur, is estimated to have had a wingspan of 6 m (Table 1) (5). The azhdarchids are one of the most successful Cretaceous pterosaur groups and include several large species with wingspans of approximately 10 m (Table 1) (6)(7)(8)(9). Quetzalcoatlus northorpi, an azhdarchid species, is regarded as one of the largest flying animals in history. The icons indicate dynamic soarer, thermal soarer, and poor soarer and summarize the main results of this study. ...
Preprint
The largest extinct volant birds ( Pelagornis sandersi and Argentavis magnificens ) and pterosaurs ( Pteranodon and Quetzalcoatlus ) are thought to have used wind-dependent soaring flight, similar to modern large birds. There are two types of soaring: thermal soaring, used by condors and frigatebirds, which involves the use of updrafts over the land or the sea to ascend and then glide horizontally; and dynamic soaring, used by albatrosses, which involves the use of wind speed differences with height above the sea surface. Previous studies have suggested that Pelagornis sandersi used dynamic soaring, while Argenthavis magnificens, Pteranodon , and Quetzalcoatlus used thermal soaring. However, the performance and wind speed requirements of dynamic and thermal soaring for these species have not yet been quantified comprehensively. We quantified these values using aerodynamic models and compared them with that of extant birds. For dynamic soaring, we quantified maximum flight speeds and maximum upwind flight speeds. For thermal soaring, we quantified the animal’s sinking speed circling at a given radius and how far it could glide losing a given height. Our results confirmed those from previous studies that Pteranodon and Argentavis magnificens used thermal soaring. Conversely, the results for Pelagornis sandersi and Quetzalcoatlus were contrary to those from previous studies. Pelagornis sandersi used thermal soaring, and Quetzalcoatlus had a poor ability both in dynamic and thermal soaring. Our results demonstrate the need for comprehensive assessments of performance and required wind conditions when estimating soaring styles of extinct flying species.
... Il nuovo millennio ha visto la scoperta di nuovi azhdarchidi. Hatzegopteryx thambema (Fig. 22) fu il primo a ricevere un nome nel XXI secolo (Buffetaut et al., 2002;Buffetaut et al., 2003). Rappresentato da molteplici elementi frammentari di cranio e arti, questo pterosauro dal Maastrichtiano della Romania, sembra essere il più grande mai conosciuto. ...
... Queste forme giganti sono sfortunatamente rappresentate da poco materiale fossile. Inizialmente, quando vi erano poche conoscenze in merito, fu stimata un'apertura alare tra 11 e 21 m (Lawson, 1975a), ma con una comprensione maggiore degli azhdarchidi le misure furono riviste in 10.5 m per Quetzalcoatlus northropi (Langston, 1981), 12 m per Hatzegopteryx (Buffetaut et al., 2003) e tra 11-13 m per Arambourgiania . Più Zhejiangopterus la parte posteriore è esente da creste, Queztalcoatlus sp. ...
... Dai resti fossili è possibile stimare una larghezza della mandibola di almeno 0.5 m, quindi può essere stiamata una varizione in lunghezza di mascella e mandibola tra 2.5 m, come in Bakonydraco, e 5 m, come in Qetzalcoatlus sp. La seconda ipotesi è ritenuta da molti, con cognizione di causa, abbastanza fantasiosa anche per uno pterosauro (Buffetaut et al., 2003). Ma l'ipotesi più conservativa rimane comunque sorprendente, dato che con i 2.5 m di fauci e almeno 0.5 m di parte posteriore del cranio la lunghezza totale raggiungerebbe almeno 3 m. ...
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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.
... Although the fossil record of Azhdarchidae pterosaurs is rather scant in Europe, fragmentary specimens have been reported from the Upper Cretaceous deposits of France, Spain, Hungary, Austria and Romania (Buffetaut, 1998(Buffetaut, , 1999(Buffetaut, , 2001(Buffetaut, , 2008(Buffetaut, , 2010Vremir, 2010;Weishampel and Jianu, 2011;Buffetaut et al., 1996Buffetaut et al., , 1997Buffetaut et al., , 2002Buffetaut et al., , 2003Buffetaut et al., , 2006Buffetaut et al., , 2011Csiki et al., 2009;Company et al., 1999;} Osi et al., 2005Vremir et al., 2009Vremir et al., , 2011Vremir et al., , 2013aVremir et al., , b, 2014bVremir et al., , 2015Vremir et al., , 2018Vullo et al., 2018). The French azhdarchid record consists of fossils from the upper Campanian to upper Maastrichtian, most of them belonging to Azhdarchidae indet. ...
... To date, only a proximal part of a right azhdarchid humerus was recovered in Austria from Campanian deposits of Grünbach Formation (Gosau Group; Buffetaut et al., 2011). Yet, to date, the greatest diversity of European Azhdarchidae comes from Romania, chiefly from the Late Cretaceous Hațeg and Transylvanian basins (Vremir, 2010;Weishampel and Jianu, 2011;Buffetaut et al., 2002Buffetaut et al., , 2003Csiki et al., 2009;Vremir et al., 2009Vremir et al., , 2011Vremir et al., , 2013aVremir et al., , b, 2014bVremir et al., , 2015Vremir et al., , 2018. ...
... Although the fossil record of azhdarchids consists mostly on postcranial elements (Nessov, 1984;Padian, 1986;Kellner, 2003;Unwin, 2003), the relatively scarce cranial elements of these pterosaurs still provide a useful comparative material. These taxa include Quetzalcoatlus Lawson, 1975(Lawson, 1975Kellner and Langston, 1996), Montanazhdarcho minor Padian, Ricql es and Horner, 1995 (Padian et al., 1995;McGowen et al., 2002), Zhejiangopterus linhaiensis Cai andWei, 1994 (Cai andWei, 1994;Unwin and Lü, 1997), Hatzegopteryx thambema (Buffetaut et al., 2002(Buffetaut et al., , 2003, Azhdarcho lancicollis Nessov (1984) and cf. Azhdarcho sp. ...
Article
The Upper Cretaceous “Hațeg Island” is not only renowned mostly for its peculiar assemblage of dwarf dinosaurs, but also for its Azhdarchidae pterosaurs including giant specimens (e.g. Hatzegopteryx thambema) and medium-sized ones (e.g. Eurazhdarcho langendorfensis), discovered in the Hațeg and Transylvanian basins of Romania. Here, we report a new species of azhdarchid pterosaur, Albadraco tharmisensis gen. et sp. nov. The material refers to two well-preserved “beak” fragments and a cervical vertebra. These fossils were discovered together in a fossil assemblage in the Maastrichtian Șard Formation, located in the southwestern area of the Transylvanian Basin (Alba District, Romania). The association of a premaxilla and a mandibular symphysis from the same specimen is the first ever reported in Europe. The fourth cervical exhibits the best three-dimensional preservation of any azhdarchid mid-cervical vertebra in Transylvania, as all specimens reported previously are poorly preserved (e.g. in E. langendorfensis) or incomplete like the specimen from Pui with a broken condyle. Albadraco tharmisensis represents a new species of a large–sized azhdarchid from the “Hațeg Island”. Its size fits between that of E. langendorfensis and H. thambema, hence confirming the co-existence of medium, large, and giant–sized azhdarchids during the Maastrichtian in Transylvania. The possibility of Ad. tharmisensis being a young Hatzegopteryx is also discussed.
... There are also differences in the humerus between the two taxa. Although the deltopectoral crest of Hatzegopteryx is unwarped (Buffetaut et al., 2003), Cryodrakon does show slight curvature of the distal end of the crest in dorsal view not seen in the former (see Witton and Habib, 2010: fig. 1). ...
Article
Azhdarchid pterosaurs have been known since 1972 from upper Campanian deposits of Alberta, Canada. Originally represented by only very fragmentary remains tentatively assigned to the genus Quetzalcoatlus, additional material uncovered over the years has revealed that the taxonomic identity of the Alberta pterosaur material is at odds with this in the light of the growing understanding of azhdarchid diversity. Here, we describe previously undocumented pterosaur remains from Alberta and reassess previously studied material. The specimens collected from the Dinosaur Park Formation can be assigned to a new genus and species Cryodrakon boreas, gen. et sp. nov. The largest elements referable to this taxon suggest that this genus reached sizes comparable to those of other giant azhdarchids.
... A wing span estimated at 5.6 m is large for Early Cretaceous pterosaurs. Pterosaurs with wingspans in excess of 5 m have hitherto only been reported from Aptian/Albian or younger strata, with most of the largest examples (wingspans estimated at 9 or more metres) being restricted to the Late Cretaceous (Maastrichtian) (see Witton, 2013) for Azhdarchidae (Quetzalcoatlus, Hatzegopteryx, Arambourgiania Lawson, 1975;Martill et al., 1998;Buffetaut et al., 2003). The largest ornithcocheirids are reported from the Albian of Brazil (Tropeognathus Kellner et al., 2013) and the Albian of eastern England (Martill and Unwin, 2012;Owen, 1859), while a large ornithocheirid from the Aptian Crato Formation of Brazil has an estimated wingspan of 5.5 m (Cheng et al., 2018). ...
Article
A partial distal left metacarpal IV of a pterodactyloid pterosaur is notable for its size. The specimen, from the Early Cretaceous (Barremian)Wessex Formation exposed on the southwest coast of the Isle of Wight, southern England is identified as an ornithocheirid, perhaps close to the Ornithocheirus, Coloborhynchus, Caulkicephalus, Anhanguera complex. A morphometric analysis suggests an original wing span of approximately 5.6 m. With an early Barremian age, this pterosaur would have been a giant for its time.