Pterosauria

This diagram illustrates how scientists believe the dinosaur group theropoda shall be classed in a phylogenetic tree, besides Sauropoda and Pterosauria. The main reason of this diagram is to show groups or families which had respiratory system like birds. AS in the diagram is abbreviations for "Airsacs", and ASW means "AirSacs supported by immobile femur and a knee-driven Walk". BL means "Bellow lungs". Airsacs are known in many different theropods, as well as in birds, which most scientists believe are descendants of dinosaurus. Air sacs are found in the primitive Tawa hallae,[1] the abelisaurid Majungasaurus,[2] as well as Allosauroids like Aerosteon.[3] There is also evidence for respiratory systems like penguinss in Deinonychosaurians.[4] The primitive bird Archaeopteryx also had airsacs (Bonde and Christiansen, 2000). It is very likely that Deinonychosaurians had airsacs. We don't know whether Deinonychosauria had a walking/breathing system with immobile thighbones, ASW (like birds) or movable thighbones. However, some people suggsest coeluosaurs had the same type of leg movement as birds ("kneedriven walking").[5] Bellow lungs are lungs like our own, which alternately is filled with air, and thereafter emptied, after which you take a new breath. This type of lungs exist in mammals, most reptiles, and most amphibians (although some frogs get their oxygen through the skin). There is no evidence for airsacs in Ornithischia, so the likely had bellow lungs. References.= ↑ (see the video at http://www.nsf.gov/news/special_reports/tawa/) ↑ (Claessens & O'connor, 2006). ↑ Alcober O.A, Sereno P.C, Larsson H.C.E et.al (2008), "Evidence for Avian Intrathoracic Air Sacs in a New Predatory Dinosaur from Argentina", Public Library of Science Journals. ↑ http://www.stumbleupon.com/su/20q5Z4/news.bbc.co.uk/2/hi/science/nature/7081166.stm ↑ http://www.geol.umd.edu/~tholtz/G104/lectures/104coelur.html.

cast of Quetzalcoatlus northropi humerus 03 - Pterosaurs Flight in the Age of Dinosaurs

cast of Quetzalcoatlus northropi humerus 02 - Pterosaurs Flight in the Age of Dinosaurs

Cast of Quetzalcoatlus northropi humerus 01 - Pterosaurs Flight in the Age of Dinosaurs

Figure 5: Measured and estimated azhdarchid pterosaur neck lengths against approximate wingspans.

Several members of Pterodactyloidea (top to bottom): Pteranodon, Pterodaustro, the skulls of several pterosaurs (Guidraco, Anhanguera, Tupandactylus, and an unnamed dsungaripterid), Quetzalcoatlus, Aerodactylus, and Coloborhynchus

Several members of Pterodactyloidea (top to bottom): Pteranodon, Pterodaustro, the skulls of several pterosaurs (Guidraco, Anhanguera, Tupandactylus, and an unnamed dsungaripterid), Quetzalcoatlus, Aerodactylus, and Coloborhynchus

Several members of Pterodactyloidea (top to bottom): Pteranodon, Pterodaustro, the skulls of several pterosaurs (Guidraco, Anhanguera, Tupandactylus, and an unnamed dsungaripterid), Quetzalcoatlus, Aerodactylus, and Coloborhynchus

Several members of Pterodactyloidea (top to bottom): Pteranodon, Pterodaustro, the skulls of several pterosaurs (Guidraco, Anhanguera, Tupandactylus, and an unnamed dsungaripterid), Quetzalcoatlus, Aerodactylus, and Coloborhynchus

Several members of Pterodactyloidea (top to bottom): Pteranodon, Pterodaustro, the skulls of several pterosaurs (Guidraco, Anhanguera, Tupandactylus, and an unnamed dsungaripterid), Quetzalcoatlus, Aerodactylus, and Coloborhynchus

Several members of Pterodactyloidea (top to bottom): Pteranodon, Pterodaustro, the skulls of several pterosaurs (Guidraco, Anhanguera, Tupandactylus, and an unnamed dsungaripterid), Quetzalcoatlus, Aerodactylus, and Coloborhynchus

The holotype of the pterosaur Lacusovagus

Australian Mesozoic pterosaurs. A, Aussiedraco molnari (QM F10613; holotype) mandible in dorsal view. Scale = 1 cm. B, Mythunga camara (QM F18896; holotype) partial skull and mandible in left lateral view. Scale = 5 cm. C, Thapunngaka shawi (KK F494; holotype) mandible in left lateral view. Scale = 5 cm. D, Ferrodraco lentoni (AODF 0876; holotype [part]) partial skull and mandible in left lateral view. Scale = 5 cm.

The Maastrichtian, Transylvanian giant azhdarchid pterosaur Hatzegopteryx sp. preys on the rhabdodontid iguanodontian Zalmoxes. Because large predatory theropods are unknown on Late Cretaceous Haţeg Island, giant azhdarchids may have played a key role as terrestrial predators in this community.

Representative taxa from the early Campanian Muthmannsdorf fauna from the Grünbach Formation, eastern Austria. A Doratodon carcharidens (Mesoeucrocodylia) mandible (PIUW 2349/57) in dorsal view (photo by Márton Rabi) B Indeterminate azhdarchid (Pterosauria, Azhdarchidae), left humerus (PIUW 2349/102) in anterior view C ‘Megalosaurus pannoniensis’ basal tetanuran (Theropoda, Tetanurae), tooth (PIUW uncatalogued) in lateral view D Mochlodon suessi (Ornithopoda, Rhabdodontidae), right dentary (holotype, PIUW 2349/2) in medial view. Scale bars equal 2 cm in A, B and D and 1 cm in C.

Representative taxa from the Santonian Iharkút fauna from the Csehbánya Formation, Bakony Mountains, western Hungary. A Pannoniasaurus inexpectatus (Squamata, Mosasauroidea), dorsal vertebra (MTM uncatalogued) in dorsal view (photo by Réka Kalmár) B Foxemys trabanti (Pleurodira, Bothremydidae), skull (MTM V 2010.215.1.) in dorsal view (photo by Márton Rabi). C Bicuspidon aff. hatzegiensis (Squamata, Borioteiioidea), left dentary (MTM 2006.112.1.) in medial view (photo by László Makádi) D Basal tetanuran (Theropoda, Tetanurae), tooth (MTM V.01.54) in ?lingual view E Indeterminate abelisaurid (Theropoda, Abelisauridae), pedal ungual phalanx (MTM V 2008.43.1.) in lateral view F Pneumatoraptor fodori (Theropoda, Paraves), left scapulocoracoid (holotype, MTM V 2008.38.1.) in lateral view G Mochlodon vorosi (Ornithopoda, Rhabdodontidae), left dentary (holotype, MTM V 2010.105.1) in lateral view H Bakonydraco galaczi (Pterosauria, Azhdarchidae), mandible (holotype, MTM 2007.110.1) in dorsal view I Iharkutosuchus makadii (Eusuchia, Hylaeochampsidae), skull (holotype, MTM 2006.52.1) in dorsal view J Hungarosaurus tormai (Ankylosauria, Nodosauridae), right dentary (MTM 2007.25.2) in lateral view K Bauxitornis mindszentyae (Aves, Enantiornithes), left tarsometatarsus (holotype, MTM V 2009.38.1) in anterior view L Ajkaceratops kozmai (Ceratopsia), fused rostral and premaxillae (holotype, MTM V 2009.192.1) in lateral view. Scale bars: 2 cm in A, V, G, H, I, J; 1 cm in D, E, F, K, L; 1 mm in C.