Aralosaurus: Difference between revisions

'''''Aralosaurus''''' was a [[genus]] of [[Hadrosauridae|hadrosaurid]] [[dinosaur]] that lived during the [[Late Cretaceous]] in what is now [[Kazakhstan]]. It is known only by a posterior half of a skull (devoid of its mandible) and some post-cranial bones<ref name="Rozhdestvensky 1968">{{cite journal|last=Rozhdestvensky|first=A.K.|title=Gadrozavry Kazakhstana [Hadrosaurs of Kazakhstan]. [Upper Paleozoic and Mesozoic Amphibians and Reptiles]|journal=Akademia Nauk SSSR, Moscow|year=1968|pages=97–141|url=http://www.dinochecker.com/papers/Hadrosaurs_of_Kazakhstan_Rozhdestvensky_1968.pdf}}</ref> found in the [[Bostobe Formation]] in rocks dated from the Upper [[Santonian]]-Lower [[Campanian]] boundary, at about 83.6 Ma (millions of years).<ref name="Prieto-Márquez & al.2013">{{cite journal|last=Prieto-Márquez|first=A.|author2=Dalla Vecchia, F.M.|author3=Gaete, R.|author4=Galobart, À.|title=Diversity, Relationships, and Biogeography of the Lambeosaurine Dinosaurs from the European Archipelago, with Description of the New Aralosaurin ''Canardia garonnensis''|journal=PLOS ONE|year=2013|volume=8|issue=7|pages=e69835|doi=10.1371/journal.pone.0069835|pmid=23922815|pmc=3724916|bibcode=2013PLoSO...869835P|doi-access=free}}</ref> Only one [[species]] is known, ''Aralosaurus tuberiferus'', described by [[Anatoly Konstantinovich Rozhdestvensky]] in 1968. The genus name means [[Aral Sea]] lizard, because it was found to the northeast of the Aral Sea.<ref name="Rozhdestvensky 1968"/> The specific epithet ''tuberiferus'' means bearing a tuber because the posterior part of the [[nasal bone]] rises sharply in front of the [[Orbit (anatomy)|orbits]] like an outgrowth.<ref name="Rozhdestvensky 1968"/> ''Aralosaurus'' was originally reconstituted with a nasal arch similar to that of North American ''[[Kritosaurus]]'' (a comparison based on a specimen now placed in the genus ''[[Gryposaurus]]'').<ref name="Rozhdestvensky 1968"/> For many years, ''Aralosaurus'' was thus placed in the clade of the [[Hadrosaurinae]]. This classification was invalidated in 2004, following the re-examination of the skull of the animal which allowed to identify in ''Aralosaurus'' many typical characters of [[Lambeosaurinae]]. In particular, this study revealed that ''Aralosaurus'' had a hollow bony structure located far in front of the orbits, which communicated with the [[respiratory tract]].<ref name="Godefroit & al.2004">{{cite journal|last1=Godefroit|first1=P.|author2=Alifanov, V.|author3=Boltsky, Y.|title=A re-appraisal of "Aralosaurus tuberiferus" (Dinosauria, Hadrosauridae) from the Late Cretaceous of Kazakhstan|journal=Bulletin de l'Institut Royal des Sciences Naturelles de Belgique, Sciences de la Terre|date=2004|volume=74Sup |issue=74|pages=139–154|url=http://biblio.naturalsciences.be/rbins-publications/bulletin-of-the-royal-belgian-institute-of-natural-sciences-earth-sciences/bulletin-of-the-royal-belgian-institute-of-natural-sciences-earth-sciences/godefroit_reappraisal_2004}}</ref> This structure being broken at its base, its shape and size remains undetermined.<ref name="Godefroit & al.2004"/> More recently, ''Aralosaurus'' has been identified as the most basal Lambeosaurinae, and placed with its close relative ''[[Canardia]]'' from the upper [[Maastrichtian]] of [[France]] in the new clade of [[Aralosaurini]].<ref name="Prieto-Márquez & al.2013"/>

''Aralosaurus'' lived about 20 million years before its close relative ''Canardia''. The latter inhabited the Ibero-Armorican Island, which was the westernmost island of the Late Cretaceous [[Europe]]an [[Archipelago]].<ref name="Csiki-Sava & al.2015">{{cite journal|last=Csiki-Sava|first=Z.|author2=Buffetaut, E.|author3=Ősi, A.|author4=Pereda-Suberbiola, X.|author5=Brusatte, S.L.|title=Island life in the Cretaceous-faunal composition, biostratigraphy, evolution, and extinction of land-living vertebrates on the Late Cretaceous European archipelago|journal=ZooKeys|year=2015|issue=469|pages=1–161|url=https://zookeys.pensoft.net/article/4474/download/pdf/|doi=10.3897/zookeys.469.8439|pmid=25610343|pmc=4296572|doi-access=free}}</ref> As no lambeosaurines were known in the rich localities of late [[Campanian]] and early [[Maastrichtian]] ages of the Ibero-Armorican Island, it was suggested that the descendants of ''Aralosaurus'' had to reach this island rather late, perhaps at the end of the early Maastrichtian or during the late Maastrichtian.<ref name="Prieto-Márquez & al.2013"/> The discovery later in Spain of numerous lambeosaurines remains in the highest levels of the lower Maastrichtian argues for the first hypothesis.<ref name="Fondevilla & al.2018">{{cite journal|last=Fondevilla|first=V.|author2=Dalla Vecchia, F.M.|author3=Gaete, R.|author4=Galobart, À.|author5=Moncunill-Solé, B.|author6=Köhler, M.|title=Ontogeny and taxonomy of the hadrosaur (Dinosauria, Ornithopoda) remains from Basturs Poble bonebed (late early Maastrichtian, tremp Syncline, Spain)|journal=PLOS ONE|year=2018|volume=13 |issue=10|pages=e0206287|doi=10.1371/journal.pone.0206287|pmid=30379888|pmc=6209292|bibcode=2018PLoSO..1306287F|doi-access=free}}</ref><ref name="Prieto-Márquez & al.2019">{{cite journal|last=Prieto-Márquez|first=A.|author2=Fondevilla, V.|author3=Sellés, A.G.|author4=Wagner, J.R.|author5=Galobart, À.|title=''Adynomosaurus arcanus'', a new lambeosaurine dinosaur from the Late Cretaceous Ibero-Armorican Island of the European Archipelago|journal=Cretaceous Research|year=2019|volume=96|pages=19–37|doi=10.1016/j.cretres.2018.12.002|bibcode=2019CrRes..96...19P |s2cid=134582286}}</ref> This [[Migration (ecology)|migration]] was probably carried out in several stages, firstly by temporary terrestrial links between the landmass of Western Asia and the eastern islands of the European archipelago, then between the different European islands up to the Ibero-Armorican Island.<ref name="Csiki-Sava & al.2015"/> ''Canardia'' was a rather archaic form for its time and the Ibero-Armorican Island was perhaps an ultimate refuge for the [[Aralosaurini]].<ref name="Prieto-Márquez & al.2013"/>

The [[sediment]]s of the Bostobe Formation consist mainly of [[clay]]s and [[sandstone]]s, and correspond to [[floodplain]] and [[Estuary|estuarine]] environments in a [[Subtropics|subtropical]] to [[tropical climate]].<ref name="Averianov & al.2015">{{cite journal|last=Averianov|first=A.|author2=Dyke, G.|author3=Danilov, I.|author4=Skutschas, P.|title=The paleoenvironments of azhdarchid pterosaurs localities in the Late Cretaceous of Kazakhstan|journal=ZooKeys|year=2015|issue=483|pages=59–80|doi=10.3897/zookeys.483.9058|pmid=25755624|pmc=4351447|doi-access=free|bibcode=2015ZooK..483...59A }}</ref> These different [[biotope]]s were located on the west coast of the [[Asia]]n continent of the time, on the edge of the ancient [[Turgai Sea]] which connected the [[Tethys Ocean|Tethys]] to the [[Arctic Ocean]].<ref name="Averianov & al.2015"/> The shallow marine waters west of this fluvial coastal plain were the site of intense organic productivity due to [[upwelling]] conditions caused by strong winds from the mainland.<ref name="Averianov & al.2015"/> These winds were also the cause of a significant [[aridification]] of the climate in this region during the Santonian and early Campanian, causing a change in the [[flora]] of [[Flowering plant|angiosperms]], with a rarefaction of broad-leaved forms and a proliferation of small and narrow-leaved species of the family [[Ulmaceae]]. Angiosperms accounted for 75% of the flora of these biotopes, the rest being [[Pinophyta|conifers]] and rare [[ginkgo]]s and [[Cycadales|cycads]].<ref name="Averianov & al.2015"/>

The locality of Shakh Shakh, where ''Aralosaurus'' was found, yielded a diverse fauna including many fish ([[Chondrichthyes|chondrichthyans]], [[Chondrostei|chondrosteans]], and [[Holostei|holosteans]]),<ref name="Averianov & al.2015"/> [[Frog|Anura]],<ref name="Averianov & al.2015"/> at least six species of [[turtle]]s<ref name="Averianov & al.2015"/> some of which had a carapace at least 75&nbsp;cm long,<ref name="Danilov & al.2015">{{cite journal|last=Danilov|first=I.G.|author2=Vitek, N.S.|author3=Averianov, A.O.|author4=Glinskiy, V.N.|title=A new soft-shelled trionychid turtle of the genus ''Khunnuchelys'' from the Upper Cretaceous Bostobe Formation of Kazakhstan|journal=Acta Palaeontologica Polonica|year=2015|volume=60|issue=1|pages=155–161|doi=10.4202/app.2013.0045|doi-access=free}}</ref> a [[Scincomorpha|scincomorph]],<ref name="Averianov & al.2015"/> [[Crocodilia|crocodylians]],<ref name="Averianov & al.2015"/> [[pterosaur]]s (''[[Aralazhdarcho]]''),<ref name="Averianov 2007a">{{cite journal|last=Averianov|first=A.O.|title=New records of azhdarchids (Pterosauria, Azhdarchidae) from the Late Cretaceous of Russia, Kazakhstan, and Central Asia|journal=Paleontological Journal|year=2007|volume=41|issue=2|pages=189–197|doi=10.1134/S0031030107020098|bibcode=2007PalJ...41..189A |s2cid=128637719|url=http://doc.rero.ch/record/16205/files/PAL_E3413.pdf }}</ref> birds,<ref name="Averianov & al.2015"/> mammals,<ref name="Averianov & al.2015"/> and several undetermined dinosaur species ([[Ankylosauridae]], [[Sauropoda]], [[Tyrannosauroidea]], [[Ornithomimidae]], [[Therizinosauroidea]], [[Troodontidae]], and [[Dromaeosauridae]]).<ref name="Dyke & Malakhov 2004">{{cite journal|last=Dyke|first=G.J.|author2=Malakhov, D.V.|title=Abundance and taphonomy of dinosaur teeth and other vertebrate remains from the Bostobynskaya Formation, north-east Aral Sea region, Republic of Kazakhstan|journal=Cretaceous Research|year=2004|volume=25|issue=5|pages=669–674|doi=10.1016/j.cretres.2004.06.004|bibcode=2004CrRes..25..669D |url=http://doc.rero.ch/record/15373/files/PAL_E2722.pdf }}</ref><ref name="Averianov 2007b">{{cite journal|last=Averianov|first=A.O.|title=Theropod dinosaurs from Late Cretaceous depositsin the northeastern Aral Sea region, Kazakhstan|journal=Cretaceous Research|year=2007|volume=28|issue=3|pages=532–544|doi=10.1016/j.cretres.2006.08.008|bibcode=2007CrRes..28..532A |url=http://doc.rero.ch/record/16144/files/PAL_E3057.pdf }}</ref><ref name="Averianov 2015">{{cite journal|last=Averianov|first=A.|title=Frontals bones of non-avian theropod dinosaurs from the Upper Cretaceous (Santonian-?Campanian) Bostobe Formation of the northeastern Aral Sea region, Kazakhstan|journal=Canadian Journal of Earth Sciences|year=2015|volume=53|issue=2|pages=168–175|doi=10.1139/cjes-2015-0099}}</ref><ref name="Averianov & al.2015"/> Elsewhere in this formation, the site of Akkurgan is distinguished by the presence of the two basal [[Hadrosauroidea|hadrosauroids]] ''[[Arstanosaurus]]''<ref name="Shilin & Suslov 1982">{{cite journal|last=Shilin|first=F.V.|author2=Suslov, Y.V.|title=A hadrosaur from the northeastern Aral Region|journal=Paleontological Journal|year=1982|volume=1982|issue=1|pages=132–136}}</ref> and ''[[Batyrosaurus]]'',<ref name="Godefroit & al.2012">{{cite book|last=Godefroit|first=P.|author2=Escuillié, F.|author3=Bolotsky, Y.L.|author4=Lauters, P.|year=2012|chapter=A new Basal Hadrosauroid Dinosaur from the Upper Cretaceous of Kazakhstan|pages=[https://archive.org/details/bernissartdinosa00gode/page/n351 335]–358|title=Bernissart Dinosaurs and Early Cretaceous Terrestrial Ecosystems|url=https://archive.org/details/bernissartdinosa00gode|url-access=limited|editor1-last=Godefroit|editor1-first=P.|publisher=Indiana University Press|location=Bloomington and Indianapolis|isbn=978-0-253-35721-2}}</ref> as well as the pterosaur ''[[Samrukia]]'' (whose jaw was first attributed to an [[Caenagnathidae|Caenagnathid]] [[Oviraptorosauria|oviraptorosaur]], then to a giant bird),<ref name="Naish & al.2012">{{cite journal|last=Naish|first=D.|author2=Dyke, G.|author3=Cau, A.|author4=Escuillié, F.|author5=Godefroit, P.|title=A gigantic bird from the Upper Cretaceous of Central Asia|journal=Biology Letters|year=2012|volume=8|issue=1|pages=97–100|doi=10.1098/rsbl.2011.0683|pmid=21835881|pmc=3259976}}</ref><ref name="Buffetaut 2011">{{cite journal|last=Buffetaut|first=E.|title=''Samrukia nessovi'', from the Late Cretaceous of Kazakhstan: A large pterosaur, not a giant bird|journal=Annales de Paléontologie|year=2011|volume=97|issue=3–4|pages=133–138|doi=10.1016/j.annpal.2011.10.001|bibcode=2011AnPal..97..133B }}</ref> which could be a junior synonym of ''Aralazhdarcho''.<ref name="Averianov & al.2015"/>