Azhdarchidae Explained

Azhdarchidae (from the Persian word Persian: [[azhdaha|azhdar]], Persian: اژدر, a dragon-like creature in Persian mythology) is a family of pterosaurs known primarily from the Late Cretaceous Period, though an isolated vertebra apparently from an azhdarchid is known from the Early Cretaceous as well (late Berriasian age, about 140 million years ago).[1] Azhdarchids are mainly known for including some of the largest flying animals discovered, but smaller cat-size members have also been found.[2] Originally considered a sub-family of Pteranodontidae, Nesov (1984)[3] named the Azhdarchinae to include the pterosaurs Azhdarcho, Quetzalcoatlus, and Titanopteryx (now known as Arambourgiania). They were among the last known surviving members of the pterosaurs, and were a rather successful group with a worldwide distribution. Previously it was thought that by the end of the Cretaceous, most pterosaur families except for the Azhdarchidae disappeared from the fossil record,[4] but recent studies indicate a wealth of pterosaurian fauna, including pteranodontids, nyctosaurids, tapejarids and several indeterminate forms.[5] In several analyses, some taxa such as Navajodactylus, Bakonydraco and Montanazhdarcho were moved from Azhdarchidae to other clades.[6] [7] [8]

Description

Azhdarchids are characterized by their long legs and extremely long necks, made up of elongated neck vertebrae which are round in cross section. Most species of azhdarchids are still known mainly from their distinctive neck bones and not much else. The few azhdarchids that are known from reasonably good skeletons include Zhejiangopterus and Quetzalcoatlus. Azhdarchids are also distinguished by their relatively large heads and long, spear-like jaws. There are two major types of azhdarchid morphologies: the "blunt-beaked" forms with shorter and deeper bills and the "slender-beaked" forms with longer and thinner jaws.[8]

It had been suggested azhdarchids were skimmers,[3] [9] but further research has cast doubt on this idea, demonstrating that azhdarchids lacked the necessary adaptations for a skim-feeding lifestyle, and that they may have led a more terrestrial existence similar to modern storks and ground hornbills.[10] [11] [12] [13] [14] Most large azhdarchids probably fed on small prey, including hatchling and small dinosaurs; in an unusual modification of the azhdarchid bodyplan, the robust Hatzegopteryx may have tackled larger prey as the apex predator in its ecosystem.[15] In another departure from typical azhdarchid lifestyles, the jaw of Alanqa may possibly be an adaptation to crushing shellfish and other hard foodstuffs.[16]

Azhdarchids are generally medium- to large-sized pterosaurs, with the largest achieving wingspans of 10-,[17] but several small-sized species have recently been discovered.[18] [19] Another azhdarchid that is currently unnamed, recently discovered in Transylvania, may be the largest representative of the family thus far discovered. This unnamed specimen (nicknamed "Dracula" by paleontologists), currently on display in the Altmühltal Dinosaur Museum in Bavaria is estimated to have a wingspan of NaNm (-2,147,483,648feet), although similarities to the contemporary azhdarchid Hatzegopteryx have also been noted.[20]

Systematics

Azhdarchids were originally classified as close relatives of Pteranodon due to their long, toothless beaks. Others have suggested they were more closely related to the toothy ctenochasmatids (which include filter-feeders like Ctenochasma and Pterodaustro). Currently it is widely agreed that azhdarchids were closely related to pterosaurs such as Tupuxuara and Tapejara.

Taxonomy

Classification after Averianov 2014, except where noted.[21]

Possible azhdarchid genera

The following genera may belong in Azhdarchidae, but may alternatively represent non-azhdarchid pterosaurs:

Phylogeny

One of the most complete cladograms of azhdarchids is presented by Andres (2021):[27]

In the analysis Cretornis and Volgadraco were recovered as pteranodontians, Alanqa was recovered as a thalassodromine, and Montanazhdarcho was recovered just outside Azhdarchidae.

The other most complete azhdarchid cladogram so far is that of Zhou et al. (2024):[28], based on Pêgas (2024):[29]

References

Notes and References

  1. Dyke . G. . Benton . M. . Posmosanu . E. . Naish . D. . 2010 . Early Cretaceous (Berriasian) birds and pterosaurs from the Cornet bauxite mine, Romania . Palaeontology . 54. 79–95. 10.1111/j.1475-4983.2010.00997.x . 15172374 . free .
  2. Web site: Watson. Traci. 2016-08-30. Cat-Size Flying Reptile Shakes Up Pterosaur Family Tree. National Geographic. dead. https://web.archive.org/web/20160901013854/http://news.nationalgeographic.com/2016/08/cat-size-pterosaurs-dinosaurs-fossils-evolution-paleontology-science/. 2016-09-01.
  3. Nesov . L. A. . 1984 . Upper Cretaceous pterosaurs and birds from Central Asia . Paleontologicheskii Zhurnal . 1984 . 1 . 47–57 . dead . https://web.archive.org/web/20090105174323/http://www.azhdarcho.com/Art/Paleoart/azhdarch3.htm . 2009-01-05.
  4. Web site: Slack KE, Jones CM, Ando T, et al. . June 2006 . Early Penguin Fossils, Plus Mitochondrial Genomes, Calibrate Avian Evolution . Molecular Biology and Evolution . 2023-07-25 . 23 . 6 . 1144–1155 . Molecular Biology and Evolution. 23 (6): 1144–55 . 10.1093/molbev/msj124. 16533822 .
  5. Systematic reinterpretation of Piksi barbarulna Varricchio, 2002 from the Two Medicine Formation (Upper Cretaceous) of Western USA (Montana) as a pterosaur rather than a bird . 10.5252/g2012n4a10 . Geodiversitas . 34 . Agnolin, Federico L. . Varricchio, David . amp. 4 . 883–894 . 2012 . 56002643 . dead. https://web.archive.org/web/20130115164102/http://www.mnhn.fr/museum/front/medias/publication/48099_g2012n4a10.pdf . 2013-01-15 .
  6. Carroll. Nathan. 2015. Reassignment of Montanazhdarcho minor as a non-azhdarchid member of the Azhdarchoidea. Journal of Vertebrate Paleontology. 35. 104. 2021-01-21. 2019-12-24. https://web.archive.org/web/20191224042705/http://vertpaleo.org/PDFS/SVP-2015-Program-and-Abstract-Book-9-22-2015.aspx. dead.
  7. Andres . B. . Myers . T. S. . 10.1017/S1755691013000303 . Lone Star Pterosaurs . Earth and Environmental Science Transactions of the Royal Society of Edinburgh . 383–398 . 2013 . 103. 3–4. 84617119 .
  8. Book: Pterosaurs: Natural History, Evolution, Anatomy. Wilton, Mark P. . 978-0691150611. 2013. Princeton University Press.
  9. Kellner . A. W. A. . Langston . W. . 1996 . Cranial remains of Quetzalcoatlus (Pterosauria, Azhdarchidae) from Late Cretaceous sediments of Big Bend National Park, Texas . Journal of Vertebrate Paleontology . 16 . 2. 222–231 . 10.1080/02724634.1996.10011310. 1996JVPal..16..222K .
  10. Book: Chatterjee . S. . Templin . R. J. . Posture, locomotion, and paleoecology of pterosaurs . 2004 . GSA Special Papers . 376 . 1–64 . 10.1130/0-8137-2376-0.1. 9780813723761.
  11. Ősi . A. . Weishampel . D.B. . Jianu . C.M. . 2005 . First evidence of azhdarchid pterosaurs from the Late Cretaceous of Hungary . Acta Palaeontologica Polonica . 50 . 4. 777–787 .
  12. Humphries . S. . Bonser . R.H.C. . Witton . M.P. . Martill . D.M. . 2007 . Did pterosaurs feed by skimming? Physical modelling and anatomical evaluation of an unusual feeding method . PLOS Biology . 5 . 8 . e204 . 10.1371/journal.pbio.0050204 . 17676976 . 1925135 . free .
  13. Witton. Mark P.. Naish, Darren. McClain, Craig R.. A Reappraisal of Azhdarchid Pterosaur Functional Morphology and Paleoecology. PLOS ONE. 28 May 2008. 3. 5. e2271. 10.1371/journal.pone.0002271. 18509539. 2386974. 2008PLoSO...3.2271W. free.
  14. Book: Pterosaurs. 9789088900938. Veldmeijer. Andre J.. Witton. Mark. Nieuwland. Ilja. 2012. Sidestone Press .
  15. M.P. . Witton . D. . Naish . Neck biomechanics indicate that giant Transylvanian azhdarchid pterosaurs were short-necked arch predators . 5 . 10.7717/peerj.2908 . 28133577 . PeerJ . 2017 . e2908. 5248582 . free .
  16. Martill . D.M. . Ibrahim . N. . 2015 . An unusual modification of the jaws in cf. Alanqa, a mid-Cretaceous azhdarchid pterosaur from the Kem Kem beds of Morocco . Cretaceous Research . 53 . 59–67 . 10.1016/j.cretres.2014.11.001. 2015CrRes..53...59M .
  17. Witton . M.P. . Habib . M.B. . 2010 . On the Size and Flight Diversity of Giant Pterosaurs, the Use of Birds as Pterosaur Analogues and Comments on Pterosaur Flightlessness . PLOS ONE . 5 . 11 . e13982 . 10.1371/journal.pone.0013982 . 21085624 . 2981443. 2010PLoSO...513982W. free .
  18. Martin-Silverstone . Elizabeth . Witton . Mark P. . Arbour . Victoria M. . Currie . Philip J. . 2016 . A small azhdarchoid pterosaur from the latest Cretaceous, the age of flying giants . Royal Society Open Science . 3 . 8. 160333 . 10.1098/rsos.160333. 27853614 . 5108964 . 2016RSOS....360333M.
  19. Prondvai . E. . Bodor . E. R. . Ösi . A. . 2014 . Does morphology reflect osteohistology-based ontogeny? A case study of Late Cretaceous pterosaur jaw symphyses from Hungary reveals hidden taxonomic diversity . Paleobiology . 40 . 2. 288–321 . 10.1666/13030. 2014Pbio...40..288P . 85673254 .
  20. News: World's largest pterodactyl skeleton goes on show in Germany. The Local Germany. 2018-03-23 . https://web.archive.org/web/20180326141611/https://www.thelocal.de/20180323/worlds-largest-pterodachtyl-dracula-museum-altmuehltal . 2018-03-26 . live.
  21. Averianov. Alexander. 2014-08-11. Review of taxonomy, geographic distribution, and paleoenvironments of Azhdarchidae (Pterosauria). ZooKeys. 432 . 1–107. 10.3897/zookeys.432.7913. free . 25152671 .
  22. Romain Vullo . Géraldine Garcia . Pascal Godefroit . Aude Cincotta . Xavier Valentin . 2018 . Mistralazhdarcho maggii, gen. et sp. nov., a new azhdarchid pterosaur from the Upper Cretaceous of southeastern France . Journal of Vertebrate Paleontology . 38 . 4. (1)-(16) . 10.1080/02724634.2018.1502670. 91265861 .
  23. Ortiz David . Leonardo D. . González Riga . Bernardo J. . Kellner . Alexander W. A. . 12 April 2022 . Thanatosdrakon amaru, gen. ET SP. NOV., a giant azhdarchid pterosaur from the upper Cretaceous of Argentina . Cretaceous Research . 135 . 105228 . 10.1016/j.cretres.2022.105228 . 2022CrRes.13705228O . 248140163 . 12 April 2022.
  24. Kellner . A.W.A. . Calvo . J.O. . 2017 . New azhdarchoid pterosaur (Pterosauria, Pterodactyloidea) with an unusual lower jaw from the Portezuelo Formation (Upper Cretaceous), Neuquén Group, Patagonia, Argentina . Anais da Academia Brasileira de Ciências . 89 . 3 suppl. 2003–2012 . 10.1590/0001-3765201720170478 . 29166530 . free .
  25. Robert M. Sullivan . Denver W. Fowler . amp . 2011 . Navajodactylus boerei, n. gen., n. sp., (Pterosauria, ?Azhdarchidae) from the Upper Cretaceous Kirtland Formation (upper Campanian) of New Mexico . Fossil Record 3. New Mexico Museum of Natural History and Science, Bulletin . 53 . 393–404 .
  26. Labita. Claudio. Martill. David M.. October 2020. An articulated pterosaur wing from the Upper Cretaceous (Maastrichtian) phosphates of Morocco. Cretaceous Research. 119. en. 104679. 10.1016/j.cretres.2020.104679. 226328607 .
  27. Andres. Brian. 2021-12-07. Phylogenetic systematics of Quetzalcoatlus Lawson 1975 (Pterodactyloidea: Azhdarchoidea). Journal of Vertebrate Paleontology. 41. sup1. 203–217. 10.1080/02724634.2020.1801703. 245078533. 0272-4634. free. 2021JVPal..41S.203A .
  28. Zhou . Xuanyu . Ikegami . Naoki . Pêgas . Rodrigo V. . Yoshinaga . Toru . Sato . Takahiro . Mukunoki . Toshifumi . Otani . Jun . Kobayashi . Yoshitsugu . 2024-11-16 . Reassessment of an azhdarchid pterosaur specimen from the Mifune Group, Upper Cretaceous of Japan . . 167 . 106046 . 10.1016/j.cretres.2024.106046 . 0195-6671.
  29. Pêgas . Rodrigo V. . 2024-06-10 . A taxonomic note on the tapejarid pterosaurs from the Pterosaur Graveyard site (Caiuá Group, ?Early Cretaceous of Southern Brazil): evidence for the presence of two species . . en . 1–22 . 10.1080/08912963.2024.2355664 . 0891-2963.

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