View source for Azendohsaurus

{{short description|Genus of herbivorous Triassic reptile}}
{{Automatic taxobox
| fossil_range = ~[[Middle Triassic|Middle]]–[[Late Triassic]]
<br />~ {{fossil range|Ladinian|Carnian|[[Ladinian]]–[[Carnian]]}}
| image =Azendohsaurus_laaroussii_teeth.png 
| image_caption =An ''Azendohsaurus'' tooth, the [[paratype]] specimen (MNHN-ALM 424) of ''A. laaroussii''
| taxon = Azendohsaurus
| display_parents = 4
| authority = Dutuit, [[1972 in paleontology|1972]]
| type_species = †'''''Azendohsaurus laaroussii'''''
| type_species_authority = Dutuit, 1972
|subdivision_ranks=
| subdivision = 
* †''A. laaroussii'' <small>Dutuit, 1972</small>
* †''A. madagaskarensis'' <small>Flynn ''et al.'', [[2010 in paleontology|2010]]</small>
}}

'''''Azendohsaurus''''' is an [[extinct]] [[genus]] of [[Herbivore|herbivorous]] [[archosauromorph]] [[reptile]] from roughly the late [[Middle Triassic|Middle]] to early [[Late Triassic|Late]] [[Triassic]] Period of [[Morocco]] and [[Madagascar]]. The [[type species]], '''''Azendohsaurus laaroussii''''', was described and named by Jean-Michel Dutuit in [[1972 in paleontology|1972]] based on partial jaw fragments and some teeth from Morocco. A second species from Madagascar, '''''A. madagaskarensis''''', was first described in [[2010 in paleontology|2010]] by John J. Flynn and colleagues from a multitude of specimens representing almost the entire skeleton. The [[Generic name (biology)|generic name]] "Azendoh lizard" is for the village of Azendoh, a local village near where it was first discovered in the [[Atlas Mountains]]. It was a bulky quadruped that unlike other early archosauromorphs had a relatively short tail and robust limbs that were held in an odd mix of sprawled hind limbs and raised forelimbs. It had a long neck and a proportionately small head with remarkably sauropod-like jaws and teeth.

''Azendohsaurus'' used to be classified as a herbivorous [[dinosaur]], at first as an [[ornithischian]] but more often as a "[[prosauropod]]" [[Sauropodomorpha|sauropodomorph]]. This was based only on its jaws and teeth, which share [[Synapomorphy|derived features]] typically found in herbivorous dinosaurs. The complete skeletal material from Madagascar, however, revealed more [[basal (phylogenetics)|basal]] characteristics [[Plesiomorphy|ancestral]] to Archosauromorpha and that ''Azendohsaurus'' was not a dinosaur at all. Instead, ''Azendohsaurus'' was actually a more primitive archosauromorph that had [[Convergent evolution|convergently evolved]] many features of the jaws and skeleton shared with the later giant [[Sauropoda|sauropod]] dinosaurs. It was found to be a member of a newly recognised group of specialised, mostly herbivorous archosauromorphs that was named the [[Allokotosauria]]. It is also the namesake and typifier of its own [[Family (biology)|family]] of allokotosaurs, the [[Azendohsauridae]]; initially the only member, the family now includes other similar allokotosaurs, such as the larger, horned azendohsaurid ''[[Shringasaurus]]'' from [[India]].

Several other groups of archosauromorphs also adapted to herbivory in the [[Triassic]], sometimes with dinosaur-like teeth that also caused confusion in their classification. ''Azendohsaurus'' is notable, however, for also convergently evolving a similar body shape to sauropodomorphs in addition to its jaws and teeth. ''Azendohsaurus'' and sauropodomorphs likely independently evolved to fill a similar [[ecological niche]] as long-necked, relatively high browsing herbivores in their environments. However, ''Azendohsaurus'' predates the large Late Triassic sauropodomorphs it resembles by several million years, and did not evolve similar body plans under the same environmental conditions. It may then have been one of the first herbivores to fill the high-browsing role that only large sauropodomorphs were thought to occupy during the Triassic, expanding the known ecological diversity of herbivorous archosauromorphs outside of dinosaurs in the Triassic Period. ''Azendohsaurus'' is also significant as it may be one of the earliest [[endothermic]] archosauromorphs known, and suggests that a warm-blooded metabolism was ancestral to the later archosaurs, including the dinosaurs.

==Description==
''Azendohsaurus'' was a stocky mid-sized reptile estimated to be roughly {{Convert|2–3|m|ft}} long. It had a small, box-shaped head with a short snout on a long neck that was raised above the shoulders. The body was broad, with a barrel-shaped chest and shoulders much taller than the hips, together with an unusually short tail. Its posture was semi-sprawled, with sprawling hind limbs and slightly elevated forelimbs. The limbs themselves are relatively short and particularly robust, with [[Digit (anatomy)|digits]] that are shorter and stouter compared to other early archosauromorphs, each with notably large, curved claws on all four feet. Superficially its appearance is comparable to that of [[sauropodomorph]] dinosaurs, along with various details of its skeleton, suggesting ''Azendohsaurus'' converged on similar traits for a relatively high-browsing, herbivorous lifestyle. ''A. laaroussii'' is poorly known compared to ''A. madagaskarensis'', and the two species are only known to differ in minor details of the jaw bones and teeth. Additional skeletal material of ''A. laaroussii'' has been reported from the [[Type locality (geology)|type locality]] of the original skull fragments, but have yet to be formally described as of 2015.<ref name="Fetal10">{{cite journal|last=Flynn|first=J.J.|author2=Nesbitt, S.J.|author3=Parrish, J.M.|author4=Ranivoharimanana, L.|author5=Wyss, A.R.|year=2010|title=A new species of ''Azendohsaurus'' (Diapsida: Archosauromorpha) from the Triassic Isalo Group of southwestern Madagascar: cranium and mandible |journal=Palaeontology|volume=53|issue=3|pages=669–688|doi=10.1111/j.1475-4983.2010.00954.x|s2cid=82341339 |doi-access=free}}</ref><ref name="nesbitt2015">{{cite journal|last1=Nesbitt|first1=S.J.|last2=Flynn|first2=J.J.|last3=Pritchard|first3=A.C.|last4=Parrish|first4=M.J.|last5=Ranivoharimanana|first5=L.|last6=Wyss|first6=A.R.|year=2015|title=Postcranial osteology of ''Azendohsaurus madagaskarensis'' (?Middle to Upper Triassic, Isalo Group, Madagascar) and its systematic position among stem archosaur reptiles.|url=https://www.researchgate.net/publication/286412354|journal=Bulletin of the American Museum of Natural History|volume=398|issue=398|pages=1–126|doi=10.1206/amnb-899-00-1-126.1|issn=0003-0090|hdl=2246/6624|s2cid=86289421|hdl-access=free}}</ref>

===Skull===
[[File:Azendohsaurus madagaskarensis skull diagram.png|left|thumb|Skull diagram of ''Azendohsaurus madagaskarensis'']]
The skull of ''A. madagaskarensis'' is almost completely known, and is robustly built with a short and boxy shape and a deep [[snout]]. The [[premaxilla]]e are gently curved at the front of the upper jaw, forming a blunt, round snout tip, while the [[Mandible|lower jaws]] have a deep, down-turned tip like those of sauropods. The [[Nares|bony nostrils]] are fused into a single (confluent) opening that faces forwards at the front of the snout, similar to those of [[rhynchosaur]]s.<ref name="Fetal10"/>

The skull has a number of traits convergent with sauropodomorphs, including the downward curving [[Mandible|dentary]], a robust dorsal process of the [[maxilla]], and several features of the teeth. The process on the maxilla usually indicates the presence of an [[antorbital fenestra]] in [[Archosauriformes|archosauriforms]], but in ''Azendohsaurus'' this space is occupied by the [[lacrimal bone]] in front of the eyes. This is a unique arrangement unknown in other Triassic archosauromorphs, except for the related ''Shringasaurus''.<ref name="shringadesc" /> The [[Orbit (anatomy)|orbits]] are almost entirely occupied by the large [[sclerotic ring]]s, suggesting large eyes. The [[Infratemporal fenestra|lower temporal fenestra]] is open at the bottom, separating the [[Jugal bone|jugal]] and the [[Quadratojugal bone|quadratojugal]] bones (a primitive trait for archosauromorphs). Also like other early archosauromorphs, ''Azendohsaurus'' has a small (3–5&nbsp;mm across) [[Pineal foramen|parietal foramen]] ("third eye") on the roof of the skull.<ref name="Fetal10"/>
[[File:Azendohsaurus madagaskarensis pterygoid.svg|thumb|231x231px|Diagram of the [[Pterygoid bone|pterygoid]], showing the numerous rows palatal teeth]]
The lower jaw is especially convergent with those of sauropodomorphs, with an [[Articular bone|articular]] joint where the jaw hinges positioned below the level of the tooth row and downward curving dentaries, as well as the similarly shaped teeth. These features are variously found in other herbivorous Triassic archosauromorphs, but this combination is only known in ''Azendohsaurus'' and sauropodomorphs.<ref name="Fetal10"/>

The teeth are all roughly leaf-shaped (lanceolate) with expanded [[Crown (tooth)|crowns]] and bulbous bases that are fused to the jaw bones (ankylothecodont).<ref name="Fetal10" /> However, the upper and lower teeth are distinctly [[heterodont]], and can be readily distinguished from each other. The upper teeth are relatively short and broad at their base, with 4–6 [[Denticle (tooth feature)|denticles]] on each surface, similar to ornithischians; the lower teeth are almost twice as tall and have twice as many denticles, more closely resembling the teeth of sauropodomorphs.<ref name=":4" /> The four premaxillary teeth are the longest teeth in the upper jaw, and are more recurved back in shape than the rest.<ref name="Fetal10"/>
[[File:Azendohsaurus madagaskarensis maxilla medial.png|thumb|left|Medial view of a right [[maxilla]] from ''A. madagaskarensis'', showing the keel on its rear half]]
The [[Palate (bones)|palate]] is unusually covered in numerous fully developed palatal teeth, with up to four sets on the [[Pterygoid bone|pterygoid]] and additional rows on the [[Palatine bone|palatine]] and [[vomer]]s. Mature ''Azendohsaurus madagaskarensis'' have at least 44 pairs of palatal teeth, in addition to the 4 teeth in each premaxilla and 11–13 in the maxilla each, along with a maximum of 17 teeth in the dentary. Palatal teeth are not uncommon in herbivorous reptiles, but in ''Azendohsaurus'' they are almost identical in shape to those along the jaw margins, but a bit stouter. Other archosauromorphs with palatal teeth have a much simpler palatal dentition of small, domed teeth.<ref name="Fetal10"/> ''[[Teraterpeton]]'' is the only other archosauromorph with similarly well developed palatal teeth.<ref>{{Cite journal|last=Sues|first=Hans-Dieter|date=2003|title=An unusual new archosauromorph reptile from the Upper Triassic Wolfville Formation of Nova Scotia|journal=Canadian Journal of Earth Sciences|volume=40|issue=4|pages=635–649|doi=10.1139/e02-048|issn=0008-4077|bibcode=2003CaJES..40..635S}}</ref>

The only described material of ''A. laaroussii'' are dentaries, maxillae, a premaxilla and several teeth. They broadly resemble ''A. madagaskarensis'' in general form but with a few distinguishing differences. The tooth count of ''A. laaroussii'' is higher, with 15–16 teeth in the maxilla compared to the 11–13 of ''A. madagaskarensis''. The teeth of ''A. laaroussii'' are also taller than those of ''A. madagaskarensis'' and have more closely packed denticles. Further distinguishing the two species is the presence of a prominent keel on the inside surface of the maxilla. This keel runs the whole length of the maxilla in ''A. laaroussii'', but is only found along the back half of it in ''A. madagaskarensis''. Any other possible differences between the two species cannot be determined without rest of the skull and skeleton.<ref name="Fetal10"/>

===Skeleton===
All the known post-cranial information for the skeleton of ''Azendohsaurus'' comes from ''A. madagaskarensis''. Much of the [[vertebral column]] is known in ''Azendohsaurus'', and although incomplete, it is estimated to have 24 presacral vertebrae (including the [[Atlas (anatomy)|atlas]] and [[Axis (anatomy)|axis]]). The [[sacrum]] of the hips has only two vertebrae, and the full number of [[caudal vertebrae]] in the tail is unknown, but it is estimated to be only around 45–55 (low for an archosaur).<ref name="nesbitt2015"/>

The [[cervical vertebrae]] change shape down the neck, beginning as characteristically elongated with long and low [[neural spines]], and getting progressively shorter in length towards the base of the neck, but with increasingly taller and narrower neural spines. This shortening is seen in the necks of other allokotosaurs like ''[[Trilophosaurus]]'', but is not found in other long-necked archosauromorphs (e.g. the middle cervicals are the longest in [[Tanystropheidae|tanystropheids]]). The neck would have been held raised up above the body, indicated by the inclined angle of the [[zygapophyses]] that connect each [[vertebra]], as well as the front zygapophyses of each vertebra being higher than those at the back. The neck was also likely held in a gentle arc, based on an articulated set of cervicals in this position.<ref name="nesbitt2015"/>

[[File:Azendohsaurus madagaskarensis palatine.png|thumb|Medial view of a right [[Palatine bone|palatine]] of ''A. madagaskarensis'' with palatal teeth]]
The [[dorsal vertebrae]] of the back generally resemble the last cervicals, with tall, vertical neural spines. These vertebrae also decrease in length down the back, but less dramatically than in the neck. The last dorsal is unique, however, as it has a neural spine angled forward. Of the two sacrals, the first vertebra is larger and more robust, with a tall neural spines over its rear half. Both sacrals have large ribs completely fused to the vertebrae that articulate with the [[Ilium (bone)|ilia]] (see below).<ref name="nesbitt2015"/>

The caudal vertebrae resemble the other vertebrae, but with backward inclined neural spines. The length of the caudals and the height of the neural spines gradually decreases down the tail, unlike some other archosauromorphs where the vertebrae elongate towards the tip. This implies that the tail was short and not tapering, but the very tip of the tail is unknown. They consistently have [[Chevron (anatomy)|chevron]] facets from the 3rd or 4th vertebrae down to the last known caudals in the series.<ref name="nesbitt2015"/>

The [[cervical rib]]s are long and thin, becoming more robust and tapered as they move down the neck. Some of the cervical ribs from bottom half of the neck have a slight facet on the inside surface at their tips that may have held the tip of the preceding rib, forming a rigid cervical rib series (also suggested for the long necked ''[[Tanystropheus]]'') that would stiffen the neck. The [[Trunk (anatomy)|trunk]] ribs are long and curve outwards, indicating ''Azendohsaurus'' had a broad and deep barrel-shaped chest. The length and curvature of the ribs decreases down the spine, and the last rib is short, fused completely to the final dorsal vertebra, and points directly outwards to the sides. Only a single set of [[Gastralium|gastralia]] is known for ''Azendohsaurus'', and their very delicate build and rarity compared to other bones suggests that it did not have a well developed basket of gastralia under the belly like some other archosauromorphs (e.g. ''[[Proterosuchus]]'').<ref name="nesbitt2015"/>

====Limbs and girdles====
[[File:Azendohsaurus madagaskarensis premaxilla.png|thumb|left|upright=0.7|Premaxilla of ''A. madagaskarensis'' with teeth]]
The forelimbs and [[Shoulder girdle|shoulders (pectoral girdle)]] of ''Azendohsaurus'' are well developed and robust. The [[scapula]] (shoulder blade) is long, about twice as tall as it is wide, matching the length and curvature of the ribs to accommodate the deep chest. The blade is concave on each side with a slightly expanded tip that is pointed at the back. The [[interclavicle]] is large and robust, and shares with ''Trilophosaurus'' and some rhynchosaurs a long "paddle-like" posterior process that is flattened and expanded towards the tip. It also has a unique forward-pointing process, a feature it shares only with ''[[Protorosaurus]]'' and some [[Araeoscelidia|early diapsids]] (most other archosauromorphs have a notch instead).<ref name="nesbitt2015"/>

The [[coracoid]]s are large and rounded, articulating with the scapula to form the glenoid (shoulder socket). The glenoid faces laterally, typical of sprawling reptiles, however, the scapular portion is directed slightly backwards, which could indicate the [[humerus]] was held in a more raised posture. The humerus itself is large and broadly expanded at both ends, leaving a relatively narrow "waisted" mid-shaft, with a very well developed [[Glossary of dinosaur anatomy#deltopectoral crest|deltopectoral crest]]. The [[Radius (bone)|radius]] is similarly stocky with slightly expanded ends, while the [[ulna]] is greatly expanded at both ends, though to a lesser extent [[Anatomical terms of location#Proximal and distal|distally]].<ref name="nesbitt2015"/>

The [[Pelvis|hips (pelvic girdle)]] are not as deep as the shoulders, with the three hip bones being roughly equal in size. The [[Ilium (bone)|ilium]] is tall and curved along the top surface, with a short rounded process at the front and a longer tapering process behind it. The [[Pubis (bone)|pubis]] points down and slightly forwards, and only has a slightly thickened expansion (boot) at the tip.  The [[ischium]] is relatively short, shorter than the ilium, and roughly triangular in shape with straight edges and a rounded rear tip. The articulation surfaces between each ischia are unusually expanded compared to other archosauromorphs. All three contribute to forming a deep, rounded [[Acetabulum|acetabulum (hip socket)]]. Unlike the open socket of dinosaurs, the internal wall of the acetabulum in ''Azendohsaurus'' is solid bone.<ref name="nesbitt2015"/>

The large sacral ribs articulate with the ilium so that it is held almost vertically, although their slight downward angle would have deflected the hip socket to face not only out away from the body but also down by about 10° to 25° from vertical. The [[femur]] is long and vaguely S-shaped, with a slightly expanded head that is not turned inwards, unlike those of dinosaurs, indicating it was not held upright. The femur is also twisted along its shaft so that the faces of the head and the knee are offset from each other by about ~75°. The [[tibia]] is roughly 75% the length of the femur, slightly bowed out, and is very robust compared those of other archosauromorphs except for the largest rhynchosaurs. The [[fibula]] by contrast is slender and more prominently twisted along its length.<ref name="nesbitt2015"/>

The extremities of ''Azendohsaurus'' are well represented in the fossils, including both a complete [[Manus (anatomy)|hand (manus)]] and [[Pes (anatomy)|foot (pes)]] each in articulation. All of the [[Carpal bones|carpals]] and [[Tarsus (skeleton)|tarsal bones]] are well ossified and distinct, and the complicated tarsus is made up of nine bones. The [[Metacarpal bones|metacarpals]] in the hand are notable as they diverge in a smooth arc, with the length of the [[Digit (anatomy)|digits]] almost symmetrical around the long third digit as well as relatively non-diverged first and fifth digits. This contrasts with the hands of other reptiles where first and fifth digits are spread out from each other and the fourth digit is the longest. The [[Metatarsal bones|metatarsals]] and digits of the foot also diverge in a smooth arc, but unlike the hand they are not symmetrical, with a long fourth toe and a short, hooked fifth digit.<ref name="nesbitt2015"/>

All the digits of the hands and feet are unusually short for an archosauromorph, contrasting with the related ''Trilophosaurus''. The [[claw]]s (or [[ungual]]s) are all very large, narrow and sharply recurved, and are significantly larger than the preceding [[Phalanx bone|finger bone]] they were attached to.<ref name="nesbitt2015"/> The digits and claws share features with those of [[dromaeosaurid]] and [[troodontid]] [[maniraptorans]], as well as other reptiles such as the [[turtle]] ''[[Proganochelys]]''. These shared traits are associated with well developed flexor tendons, and it is suggested to be an adaptation for withstanding forces involved in digging.<ref name="bitestuff">{{cite web|url=https://qilong.wordpress.com/2015/12/11/azendohsaurus-former-dinosaur-recieves-makeover/|title=''Azendohsaurus'' – Former Dinosaur – {{sic|Rec|ieves|nolink=y}} Makeover|last=Headden|first=Jaime A.|date=December 11, 2015|work=The Bite Stuff|access-date=2019-01-31}}</ref>

==History of Discovery==
=== ''A. laaroussii'' ===
[[File:Azendohsaurus laaroussii.jpg|thumb|upright|Illustration of a partial ''A. laaroussii'' jaw bone with teeth]]

==== Early discoveries ====
The first fossils of ''Azendohsaurus laaroussii'' were discovered in a northern part the [[Timezgadiouine Formation]] in [[Morocco]], which is found within the [[Argana Basin]] of the [[High Atlas]]. The fossil beds consist of [[sandstone]]s and red clay [[mudstone]]s, and were excavated by Jean-Michel Dutuit between 1962 and 1969. The fossils of ''A. laaroussii'' are known from only a single layer within the formation, in an [[outcrop]] numbered XVI by Dutuit at the base of the T5 (or Irohalene) member. The T5 member has traditionally been roughly dated to the early Late Triassic in age using vertebrate [[biostratigraphy]] based on the presence of the [[phytosaur]] [[Arganarhinus|''"Paleorhinus" magnoculus'']], as part of the Carnian dated '"''Palaeorhinus''" biochron',<ref>{{Cite journal|last1=Hunt|first1=Adrian P.|last2=Lucas|first2=Spencer G.|date=1991|title=The ''Paleorhinus'' biochron and the correlation of the non-marine Upper Triassic of Pangaea|url=https://mail.palaeo-electronica.org/publications/palaeontology-journal/archive/34/2/article_pp487-501?view=abstract|journal=Palaeontology|volume=34|issue=2|pages=487–501|access-date=2019-07-19|archive-date=2021-04-25|archive-url=https://web.archive.org/web/20210425122107/https://mail.palaeo-electronica.org/publications/palaeontology-journal/archive/34/2/article_pp487-501?view=abstract|url-status=dead}}</ref> although this method of correlating and dating global Triassic sequences may be inaccurate and the date for the T5 member remains uncertain.<ref name=":7" /><ref>{{Cite journal|last=Butler|first=Richard J.|date=2013|title='Francosuchus' trauthi is not Paleorhinus: implications for Late Triassic vertebrate biostratigraphy|journal=Journal of Vertebrate Paleontology|language=en|volume=33|issue=4|pages=858–864|doi=10.1080/02724634.2013.740542|s2cid=86386615|issn=0272-4634}}</ref>

The first fossils consisted of only a partial tooth-bearing dentary fragment and some associated teeth. This material was discovered by J. M. Dutuit in 1965 and described in 1972, who believed it to belong to a herbivorous ornithischian dinosaur, as well as one of the oldest dinosaurs yet discovered. He named the genus "Azendoh lizard", after the nearby Azendoh village located only 1.5&nbsp;km to the west of where the fossils were discovered. The specific name, ''A. laaroussii'', is in honour of Laaroussi, the name of a technician from the Moroccan geological mapping service who first discovered the site where ''Azendohsaurus'' was found.<ref name=":4" /><ref name=":0">{{Cite journal|last=Dutuit|first=J. M.|date=1972|title=Decouverte d'un dinosaure ornithischien dans le Trias superieur de l'Atlas occidental marocain.|journal=Comptes rendus de l'Académie des Sciences de Paris|volume=275|pages=2841–2844}}</ref>

Dutuit's description of ''Azendohsaurus'' as an ornithischian was soon challenged by [[palaeontologist]] [[Richard A. Thulborn|Richard Thulborn]] two years later in 1974, who was the first to suggest that ''Azendohsaurus'' was a "prosauropod" instead.<ref name=":1">{{Cite journal|last=Thulborn|first=Richard A.|date=1974|title=A new heterodontosaurid dinosaur (Reptilia: Ornithischia) from the Upper Triassic Red Beds of Lesotho|journal=Zoological Journal of the Linnean Society|language=en|volume=55|issue=2|pages=151–175|doi=10.1111/j.1096-3642.1974.tb01591.x|issn=0024-4082|via=Oxford University Press}}</ref> The same conclusion was made by [[José Bonaparte|José Boneparte]] after examining the material himself in 1976.<ref>{{Cite journal|last=Bonaparte|first=J. F.|date=1976|title=''Pisanosaurus mertii'' Casamiquela and the Origin of the Ornithischia|journal=Journal of Paleontology|volume=50|issue=5|pages=808–820|jstor=1303575}}</ref> This re-identification was favoured by researchers in subsequent publications, and it was variously referred to the "prosauropod" families [[Anchisauridae]]<ref>{{Cite book |title=Vertebrate Paleontology and Evolution |last=Carroll |first=Robert L. |publisher=[[W. H. Freeman and Company]] |year=1988 |isbn=0716718227 |pages=[https://archive.org/details/vertebratepaleon0000carr/page/621 621] |oclc=922750908 |url=https://archive.org/details/vertebratepaleon0000carr/page/621 }}</ref><ref name=":2" /> and [[Thecodontosauridae]]<ref>{{Cite book|title=The Dinosauria|last=Galton|first=P. M.|publisher=University of California Press|year=1990|isbn=9780520067264|editor-last=Weishampel|editor-first=D. B.|location=Berkeley|pages=335, 338|chapter=Basal Sauropodomorpha—Prosauropoda|oclc=154697781|editor-last2=Dodson|editor-first2=P.|editor-last3=Osmólska|editor-first3=H.}}</ref><ref>{{Cite book|title=In the shadow of the dinosaurs: early Mesozoic tetrapods|date=1994|publisher=Cambridge University Press|editor-last1=Fraser |editor-first1=Nicholas C. |editor-last2=Sues |editor-first2=Hans-Dieter|isbn=0521452422|location=Cambridge|oclc=28293773}}</ref><ref>{{Cite journal|last1=Galton|first1=Peter M.|last2=Heerden|first2=Jacques|date=1998|title=Anatomy of the prosauropod dinosaur ''Blikanasaurus cromptoni'' (Upper Triassic, South Africa), with notes on the other tetrapods from the lower Elliot Formation|url=https://www.academia.edu/21926394|journal=Paläontologische Zeitschrift|language=en|volume=72|issue=1–2|pages=163–177|doi=10.1007/bf02987824|s2cid=128464155|issn=0031-0220}}</ref>  without further explanation. Dutuit himself even agreed that ''Azendohsaurus'' was likely to be a "prosauropod" in 1983,<ref>{{Cite journal|last1=Dutuit|first1=J. M.|last2=Heyler|first2=Daniel|date=1983|title=Taphonomie des gisements de Vertebres triasiques marocains (couloir d'Argana) et paleogeographie|journal=Bulletin de la Société Géologique de France|language=en|volume=S7-XXV|issue=4|pages=629|doi=10.2113/gssgfbull.s7-xxv.4.623|issn=0037-9409}}</ref> although not long before in 1981 he had briefly regarded it as a "pre-ornithischian".<ref name=":4">{{Cite journal|last=Gauffre|first=F. X.|date=1993|title=The prosauropod dinosaur ''Azendohsaurus laaroussii'' from the Upper Triassic of Morocco.|url=https://www.palass.org/sites/default/files/media/publications/palaeontology/volume_36/vol36_part4_pp897-908.pdf|journal=Palaeontology|volume=36|issue=4|pages=897–908|via=The Palaeontological Association|archive-date=2021-04-25|access-date=2019-07-19|archive-url=https://web.archive.org/web/20210425122055/https://www.palass.org/sites/default/files/media/publications/palaeontology/volume_36/vol36_part4_pp897-908.pdf|url-status=live}}</ref><ref>{{Cite journal|last1=Biron|first1=P. E.|last2=Dutuit|first2=J. M.|date=1981|title=Figurations sédimentaires et traces d'activité au sol dans le Trias de la formation d'Argana et de l'Ourika (Maroc).|journal=Bulletin du Muséum National d'Histoire Naturelle, Section C|volume=3|issue=4|pages=399–427|issn=0181-0642}}</ref>

In 1985, palaeontologist [[Peter Galton]] suggested that Dutuit's original "Azandohsaurus {{sic}}" material included the jaw of a "prosauropod" and the tooth of a [[Fabrosauridae|fabrosaurid]] ornithischian (a now defunct grouping of early ornithischians), based on the differences in the shape of the teeth.<ref>{{Cite journal|last=GALTON|first=PETER M.|date=1985|title=Diet of prosauropod dinosaurs from the late Triassic and early Jurassic|url=https://www.academia.edu/21926391|journal=Lethaia|language=en|volume=18|issue=2|pages=105–123|doi=10.1111/j.1502-3931.1985.tb00690.x|issn=0024-1164}}</ref> This suggestion was refuted by François-Xavier Gauffre in 1993 when he re-described the material, as well describing additional jaw bones and teeth including two maxillae. He correctly concluded that the material belonged to a single [[taxon]], but assigned the genus to "Prosauropoda" ''[[incertae sedis]]'' based again on the characteristics of the jaws and teeth. However, he could not determine its position within "Prosauropoda" due to the ambiguous distribution of these traits in early herbivorous dinosaurs, as well as a lack of any comparable Triassic reptiles, so he referred it to ''incertae sedis''.<ref name=":4" /> His assessment was accepted by many other researchers in the years following up until the description of the new material from the Madagascan species.<ref name=":6">{{Cite journal|last=Lucas|first=Spencer G.|date=1998|title=Global Triassic tetrapod biostratigraphy and biochronology|journal=Palaeogeography, Palaeoclimatology, Palaeoecology|volume=143|issue=4|pages=347–384|doi=10.1016/s0031-0182(98)00117-5|issn=0031-0182|bibcode=1998PPP...143..347L|url=http://doc.rero.ch/record/16228/files/PAL_E3457.pdf|archive-date=2023-12-28|access-date=2023-01-21|archive-url=https://web.archive.org/web/20231228125603/https://doc.rero.ch/record/16228/files/PAL_E3457.pdf|url-status=live}}</ref><ref name=Jalil99>{{Cite journal|last=Jalil|first=N.-E.|date=1999|title=Continental Permian and Triassic vertebrate localities from Algeria and Morocco and their stratigraphical correlations|journal=Journal of African Earth Sciences|volume=29|issue=1|pages=219–226|doi=10.1016/s0899-5362(99)00091-3|issn=1464-343X|bibcode=1999JAfES..29..219J}}</ref><ref>{{Cite journal|last1=Langer|first1=Max C.|last2=Abdala|first2=Fernando|last3=Richter|first3=Martha|last4=Benton|first4=Michael J.|date=1999|title=A sauropodomorph dinosaur from the Upper Triassic (Carnian) of southern Brazil|url=http://palaeo.gly.bris.ac.uk/Benton/reprints/1999Saturnalia.pdf|journal=Comptes Rendus de l'Académie des Sciences, Série IIA|volume=329|issue=7|pages=511–517|doi=10.1016/s1251-8050(00)80025-7|issn=1251-8050|bibcode=1999CRASE.329..511L|access-date=2019-07-19|archive-date=2007-07-15|archive-url=https://web.archive.org/web/20070715150054/http://palaeo.gly.bris.ac.uk/Benton/reprints/1999Saturnalia.pdf|url-status=dead}}</ref><ref>{{Cite journal|last1=Yates|first1=Adam M.|last2=Kitching|first2=James W.|date=2003-08-22|title=The earliest known sauropod dinosaur and the first steps towards sauropod locomotion|url=http://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC1691423&blobtype=pdf|journal=Proceedings of the Royal Society of London B: Biological Sciences|language=en|volume=270|issue=1525|pages=1753–1758|doi=10.1098/rspb.2003.2417|issn=0962-8452|pmc=1691423|pmid=12965005|archive-date=2019-11-11|access-date=2019-07-19|archive-url=https://web.archive.org/web/20191111231654/http://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC1691423&blobtype=pdf|url-status=live}}</ref><ref>{{Cite journal|last=Durand|first=J.F.|date=2005|title=Major African contributions to Palaeozoic and Mesozoic vertebrate palaeontology|journal=Journal of African Earth Sciences|volume=43|issue=1–3|pages=53–82|doi=10.1016/j.jafrearsci.2005.07.014|issn=1464-343X|bibcode=2005JAfES..43...53D}}</ref><ref name="Ietal" />

==== Later finds to present ====
New material from the [[Type locality (geology)|type locality]] of ''A. laaroussii'', including parts of the post-cranial skeleton, was reported on in 2002 at the annual conference of the [[Society of Vertebrate Paleontology]] by Nour-Eddine Jalil and Fabien Knoll. The additional material included presacral vertebrae, limb bones and limb girdles. The material was disarticulated, and was only attributable to ''A. laaroussii'' due to its association with recognised fragments of the skull and jaws. The post-cranial material was recognised as non-dinosaurian, but still believed to be an [[ornithodiran]] [[archosaur]] related to dinosaurs.<ref name="Jalil">{{cite conference |title=Is ''Azendohsaurus laaroussii'' (Carnian, Morocco) a dinosaur? |last1=Jalil |first1=Nour-Eddine |last2=Knoll |first2=Fabien |date=2002 |page=70A |url=http://www.miketaylor.org.uk/tmp/svp-abstracts/SVP%202002%20abstracts.pdf |book-title=Society of Vertebrate Paleontology 62nd Annual Meeting Program & Abstracts |location=Norman, Oklahoma | volume=62 |conference=Society of Vertebrate Paleontology 62nd Annual Meeting}}</ref> If correctly associated with the jaws and teeth, this indicated ''Azendohsaurus''  was not closely related to any herbivorous dinosaurs, despite their similarities.<ref>{{Cite book|title=The Dinosauria, second edition|url=https://archive.org/details/dinosauriandedit00weis|url-access=limited|last1=Galton|first1=P. M.|last2=Upchurch|first2=P.|publisher=University of California Press|year=2004|isbn=9780520254084|editor-last=Weishampel|editor-first=D. B.|location=Berkeley|pages=[https://archive.org/details/dinosauriandedit00weis/page/n250 232]–258|chapter=Prosauropoda|oclc=154697781|editor-last2=Dodson|editor-first2=P.|editor-last3=Osmólska|editor-first3=H.}}</ref> Similarly, teeth from other purported Triassic ornithischians were later found to belong to previously unrecognised herbivorous reptiles, such as the [[pseudosuchia]]n ''[[Revueltosaurus]]'', highlighting the possibility for mistaken identities in other purported herbivorous Triassic dinosaurs, including ''Azendohsaurus''.<ref>{{Cite journal|last1=Parker|first1=William G.|last2=Irmis|first2=Randall B.|last3=Nesbitt|first3=Sterling J.|last4=Martz|first4=Jeffrey W.|last5=Browne|first5=Lori S.|date=2005-05-07|title=The Late Triassic pseudosuchian ''Revueltosaurus callenderi'' and its implications for the diversity of early ornithischian dinosaurs|url=http://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC1564089&blobtype=pdf|journal=Proceedings of the Royal Society of London B: Biological Sciences|language=en|volume=272|issue=1566|pages=963–969|doi=10.1098/rspb.2004.3047|issn=0962-8452|pmc=1564089|pmid=16024353}}</ref>

The new post cranial material from ''A. laaroussii'' was described as part of a [[Doctor of Philosophy|Ph.D]] [[thesis]] by Khaldoune in 2014,<ref>{{cite thesis |last=Khaldoune |first=F. |date=2014 |title=Les vertébrés du Permien et du Trias du Maroc (Bassin d'Argana, Haut Atlas Occidental) avec la réévaluation d{{'}}''Azendohsaurus laaroussii'' (Reptilia, Archosauromorpha) et la description de Reptilia Moradisaurinae et Rhynchosauria nouveaux: anatomie, relations phylogénétiques et implications biostratigraphiques. |type=Unpublished Ph.D thesis |publisher=[[Cadi Ayyad University|University Cadi Ayyad]], [[Marrakesh]], [[Morocco]] |language=fr}}</ref> but as of 2019 this thesis has not yet been published and the material remains officially undescribed in published literature. However, it has now more confidently been referred to ''A. laaroussii'' after the description of the Madagascan material, and was found to share at least two diagnostic post cranial traits with the Madagascan species.<ref name="nesbitt2015" /><ref name="Therm"/> All the material from ''A. laaroussii'', including the holotype and unpublished post crania, is housed at the [[National Museum of Natural History (France)|Muséum National d'Histoire Naturelle]] in [[Paris]], [[France]].<ref name="Therm"/><ref>{{Cite journal|last1=Pritchard|first1=Adam C.|last2=Nesbitt|first2=Sterling J.|date=2017|title=A bird-like skull in a Triassic diapsid reptile increases heterogeneity of the morphological and phylogenetic radiation of Diapsida|journal=Royal Society Open Science|language=en|volume=4|issue=10|pages=170499|doi=10.1098/rsos.170499|issn=2054-5703|pmc=5666248|pmid=29134065|bibcode=2017RSOS....470499P}}</ref>

=== ''A. madagaskarensis'' ===

==== Initial discoveries ====
In 1997 through to 1999, fossils of a new archosauromorph were discovered by an international expedition in southwestern [[Madagascar]] and were recovered over the following decade. The fossils were found in a single [[bone bed]], referred to as M-28, that was only tens of centimetres thick across a 100 metre stretch of outcrop exposed as an uplifted [[river terrace]] not far from the east bank of the Malio River, just outside of the [[Isalo National Park]], north-west of the town of [[Ranohira]] and to the east of [[Sakahara]]. The locality was from the base of the Middle–Late Triassic [[Makay Formation]], also referred to as Isalo II, a part of the Isalo "Group" in the [[Morondava Basin]].<ref name="Fetal10" /><ref name="Fetal08">{{cite journal |last=Flynn |first=J. |author2=Nesbitt, S.|author3= Parrish, M.|author4= Ranivoharimanana, L.|author5= Wyss, A. |year=2008 |title=A new species of basal archosauromorph from the Late Triassic of Madagascar |journal=Journal of Vertebrate Paleontology |volume=28 | issue = Suppl. 3 |pages=78A | doi = 10.1080/02724634.2008.10010459}}</ref><ref name=":5" />

Previously, the formation had been believed to be Early to Middle Jurassic in age, although the earlier discovery of the rhynchosaur ''[[Isalorhynchus]]'' had revised that estimate to the Middle Triassic. The tetrapod fossils recovered in the 1997–99 expedition confirmed the Isalo II was Triassic in age, but instead suggested a younger Carnian age. The age of the formation has also been correlated to the ''Santacruzodon'' Assemblage Zone (AZ) from the [[Santa Maria Formation]] in South America based on the shared genera of [[Traversodontidae|traversodontid]] [[cynodonts]], with a similar late Ladinian or early Carnian age.<ref name=Melo15>{{cite journal |last1=Melo |first1=T.P. |last2=Abdala |first2=F. |last3=Soares |first3=M.B. |year=2015 |title=The Malagasy cynodont ''Menadon besairiei'' (Cynodontia; Traversodontidae) in the Middle-Upper Triassic of Brazil |journal=[[Journal of Vertebrate Paleontology]] |volume=5 |issue=6 |pages=e1002562 |doi=10.1080/02724634.2014.1002562 |s2cid=128925370 |issn=1937-2809 |url=https://www.researchgate.net/publication/282351998}}</ref> The ''Santacruzodon'' AZ has been more reliably dated through [[radiometric dating|radioisotope]] [[uranium-lead dating|U—Pb]] dating, suggesting a maximum depositional age of 237 ±1.5 million years in the early Carnian.<ref>{{cite journal |last1=Schmitt |first1=M.R. |last2=Martinelli |first2=A.G. |last3=Melo |first3=T.P. |last4=Soares |first4=M.B. |year=2019 |title=On the occurrence of the traversodontid ''Massetognathus ochagaviae'' (Synapsida, Cynodontia) in the early late Triassic ''Santacruzodon'' Assemblage Zone (Santa Maria Supersequence, southern Brazil): Taxonomic and biostratigraphic implications |journal=[[Journal of South American Earth Sciences]] |volume=93 |pages=36–50 |doi=10.1016/j.jsames.2019.04.011|bibcode=2019JSAES..93...36S |s2cid=150326079 }}</ref>

The bone bed contained material from almost "a dozen" individuals of varying ages and size, all from a single species.<ref name="Fetal08" /> The material was very well preserved, generally preserving the three-dimensional shape of the bones with very little crushing or distortion in some of the specimens. Based on the state of preservation, some of the bones were believed to have been buried rapidly while others were exposed for longer on the surface, where they were weathered, cracked and possibly trampled on before burial.<ref name="nesbitt2015"/>

As with ''A. laaroussii'', the teeth and jaws were the first material to be recovered and described from the bone bed. These were initially mistaken to belong two different species based on the difference in tooth shape in the upper and lower jaws, but one of them was recognised as closely resembling ''A. laaroussii'', sharing a keel on the inside surface of the maxilla and expanded, leaf-shaped teeth, among other features''.'' Like ''A. laaroussii'', both of these supposed species were also misidentified as "prosauropods"; a species of ''Azendohsaurus'' or a related taxon and another, more typical "prosauropod".<ref name=":5">{{Cite journal|last1=Flynn|first1=John J.|last2=Parrish|first2=J. Michael|last3=Rakotosamimanana|first3=Berthe|last4=Simpson|first4=William F.|last5=Whatley|first5=Robin L.|last6=Wyss|first6=André R.|date=1999-10-22|title=A Triassic Fauna from Madagascar, Including Early Dinosaurs|journal=Science|language=en|volume=286|issue=5440|pages=763–765|doi=10.1126/science.286.5440.763|issn=0036-8075|pmid=10531059}}</ref><ref>{{Cite journal|last1=Flynn|first1=John J.|last2=Parrish|first2=J. Michael|last3=Rakotosamimanana|first3=Berthe|last4=Ranivoharimanana|first4=Lovasoa|last5=Simpson|first5=William F.|last6=Wyss|first6=André R.|date=2000-09-25|title=New Traversodontids (Synapsida: Eucynodontia) from the Triassic of Madagascar|journal=Journal of Vertebrate Paleontology|language=en|volume=20|issue=3|pages=422–427|doi=10.1671/0272-4634(2000)020[0422:ntseft]2.0.co;2|s2cid=130041740 |issn=0272-4634}}</ref> Further discoveries of associated material clarified that all the jaw material and the rest of the skeletons were from a single, new species of ''Azendohsaurus''.<ref name="Fetal10" />

==== Reinterpretation ====
[[File:Azendohsaurus madagaskarensis braincase.png|left|thumb|[[Braincase]] of UA 7-20-99-653, the holotype of ''A. madagaskarensis'', in occipital view]]

Even preliminary examination of the rest of the skull and skeleton from the Madagascan species confirmed that ''Azendohsaurus'' was not a dinosaur, and was instead an aberrant herbivorous archosauromorph that was only distantly related to dinosaurs, let alone sauropodomorphs.<ref name="Fetal08" /> A description of the cranial material was published first in May, 2010 by John J. Flynn and colleagues, who also officially named and diagnosed it as a new species of ''Azendohsaurus'', '''''Azendohsaurus madagaskarensis''''', named for its country of origin. This was also the first time ''Azendohsaurus'' was determined to be a non-dinosaur in the published literature.<ref name="Fetal10" />

In December, 2015, the rest of the skeleton of ''A. madagaskarensis'' was formally described and published by [[Sterling Nesbitt|Sterling J. Nesbitt]] and colleagues, providing the first detailed examination of the full anatomy of ''Azendohsaurus'' from the now almost completely known skeleton. In addition to comparing its anatomy, they were also able to analyse its evolutionary relationships to other Triassic reptiles in a [[Phylogenetics|phylogenetic]] context for the first time.<ref name="nesbitt2015"/>

The preservation of the material was described as "generally excellent" by Nesbitt and colleagues, and the amount of overlapping material made it easier to determine the original morphology from distorted and broken bones. Much of the material was found disarticulated and sometimes isolated, but a number of specific parts of the body were found articulated in life position, including sections of the neck, back, hands and feet. Most of the material was similarly sized, with a range of about 25% between the smallest and largest specimens, although the significance of this is not understood and it could be related to [[ontogeny]], individual variation or [[sexual dimorphism]].

The well preserved nature of much of the material also allowed for reinterpretations of parts of the skeleton of other archosauromorphs, such as the hand of ''Trilophosaurus''. The hands of other archosauromorphs are often poorly known, and so their preservation in ''Azendohsaurus'' is considered important for understanding their evolution in early archosauromorphs. All the specimens of ''A. madagaskarensis'' are permanently housed in both the [[University of Antananarivo]] in Madagascar (including the holotype) and at the [[Field Museum of Natural History]] in [[Chicago]], [[Illinois]], including casts of some of the original specimens.<ref name="nesbitt2015" />

==Classification==

=== Initial attempts ===
[[File:Teraterpeton.png|thumb|left|Life restoration of ''[[Teraterpeton]]'', another [[Allokotosauria|allokotosaur]] of previously uncertain placement]]
''Azendohsaurus'' was first misidentified as an ornithischian dinosaur by Dutuit, based on shared characteristics of its teeth such as the leaf-like shape and the number of denticles.<ref name=":0" /> It was later believed to be a sauropodomorph instead by other researchers, assigned to the defunct infraorder "Prosauropoda" (then believed to be a distinct [[Monophyly|monophyletic]] group related to sauropods, now known to be a [[Paraphyly|paraphyletic]] grade) based on the morphology of its lower jaw, maxilla and teeth, such as the downward curving dentary and absence of a [[Ornithischia#Predentary|predentary bone]], one of the characteristic traits of ornithischians.<ref name=":1" /><ref name=":2">{{Cite journal|last1=Shubin|first1=Neil H.|last2=Sues|first2=Hans-Dieter|date=1991|title=Biogeography of early Mesozoic continental tetrapods: patterns and implications|journal=Paleobiology|language=en|volume=17|issue=3|pages=214–230|doi=10.1017/S0094837300010575|s2cid=130066204 |issn=0094-8373}}</ref><ref name="Ietal">{{cite journal |last=Irmis |first=R.B. |author2=Parker, W.G. |author3=Nesbitt, S.J. |author4=Liu, J. |year=2007 |title=Early ornithischian dinosaurs: the Triassic record |journal=Historical Biology |volume=19 |issue=1 |pages=3–22 |doi=10.1080/08912960600719988 |s2cid=11006994 |url=http://socrates.berkeley.edu/~irmisr/trornith.pdf |archive-date=2012-02-24 |access-date=2010-05-30 |archive-url=https://web.archive.org/web/20120224215611/http://socrates.berkeley.edu/~irmisr/trornith.pdf |url-status=live }}</ref> These misidentifications were caused by the convergence in jaw and tooth shape between it and the herbivorous dinosaurs while its true phylogenetic relationships could not be realised due to the absence of other bones of the skull and skeleton.

The non-dinosaurian identity of ''Azendohsaurus'' was first hinted at after the discovery of additional skeletal material recovered from the type locality. This was based on the presence of traits such as a solid hip socket (acetabulum), and a proximal [[fourth trochanter]] on the femur that also lacked an inward-facing head, which are typical of dinosaur skeletons. While evidently not a dinosaur, it was tentatively interpreted as an ornithodiran archosaur, still closely related to dinosaurs.<ref name="Jalil" />

The discovery of more complete material from Madagascar prompted the first formal classification ''Azendohsaurus'' as non-dinosaurian by Flynn and colleagues in 2010 through a detailed description of its cranial anatomy and were able to clarify its relationships further. They instead recognised it to be a more basal archosauromorph, far removed dinosaurs and closely related to but outside of the clade of [[Archosauriformes]]. As well as the derived, sauropodomorph-like features, the skull also had numerous primitive traits for archosauromorphs, including an open-bottomed lower temporal fenestra, extensive palatal teeth, a pineal foramen and no external [[Mandibular fenestra|mandibular]] or antorbital fenestrae. However, its exact relationships still remained unknown beyond a position as an indeterminate non-archosauriform archosauromorph.<ref name="Fetal10" /><ref name="Fetal08" />

=== Recognition of Allokotosauria ===
''Azendohsaurus'' was included in a [[phylogenetic analysis]] of Triassic archosauromorphs for the first time in 2015 by Nesbitt and colleagues, utilising all of the new information from the skull and skeleton and a broad sample of various Triassic archosauromorph species, where it was recovered as closely related to other enigmatic herbivorous Triassic reptiles such as ''[[Trilophosaurus]]'' and ''[[Teraterpeton]]''. This newly recognised grouping of archosauromorphs was named [[Allokotosauria]], meaning "strange reptiles", for the unusual qualities of the reptiles that belonged to the group. ''Azendohsaurus'' was found to be the [[Sister group|sister taxon]] of the [[Family (biology)|family]] [[Trilophosauridae]], and was recognised as the sole member of its own family, the [[Azendohsauridae]], due its distinctiveness even amongst other allokotosaurs.<ref name="nesbitt2015"/> A similar result was recovered by another large analysis of archosauromorph phylogeny in 2016 by [[Martin Ezcurra|Martín D. Ezcurra]], who found a monophyletic Allokotosauria containing ''Azendohsaurus'' and ''Trilophosaurus''.<ref name="Ezcurra2016">{{Cite journal|last=Ezcurra |first=M.D. |date=2016 |title=The phylogenetic relationships of basal archosauromorphs, with an emphasis on the systematics of proterosuchian archosauriforms |journal=[[PeerJ]] |language=en |volume=4 |pages=e1778 |doi=10.7717/peerj.1778 |pmid=27162705 |pmc=4860341 |issn=2167-8359 |doi-access=free }}</ref>

Allokotosaurs are recognised as often having specialised jaws and teeth, as well as sharing a number of [[synapomorphies]] that include several reversals to more [[plesiomorphic]] (ancestral) traits of archosauromorphs, as well as at least two derived traits. The clade is considered to be well supported in these analyses. However, although closely related, the craniodental characteristics of allokotosaurs vary dramatically, and among them ''Azendohsaurus'' was characterised by having laterally compressed, serrated teeth present throughout the length of the jaws (unlike the 'beaked' jaws of trilophosaurids). ''Azendohsaurus'' broadly shares with other azendohsaurids features such as confluent nares, leaf-shaped teeth and a long neck, but ''Azendohsaurus'' itself is distinguished by the distinctive groove on the inside surface of the maxilla and tooth crowns that are expanded above the base.<ref name="shringadesc" />

[[File:Shringasaurus indicus life restoration.jpg|thumb|Life restoration of ''[[Shringasaurus]]'', a closely related [[Azendohsauridae|azendohsaurid]]]]

In 2017, another large allokotosaur was described from the Middle Triassic of [[India]] by Saradee Sengupta and colleagues, named ''[[Shringasaurus|Shringasaurus indicus]].'' ''Shringasaurus'' was very similar to ''Azendohsaurus'', and they were found to be closely related, supporting the existence of Azendohsauridae as a distinct family from the trilophosaurids. The same analysis also recovered ''[[Pamelaria]]'', another long necked archosauromorph from India, as a basal azendohsaurid. Similarities between ''Pamelaria'' and ''Azendohsaurus'' had been noted by Nesbitt and colleagues in 2015, including confluent nares, serrated teeth and low cervical spines, but their analysis favoured a position in Allokotosauria basal to azendohsaurids.<ref name="nesbitt2015"/> The 2017 analysis also confirmed the close relationship between ''A. laaroussii'' and ''A. madagaskarensis'' within Azendohsauridae, strengthening their shared referral to the genus ''Azendohsaurus''. A 2018 analysis of Triassic archosauromorphs failed to recover Allokotosauria, but still recovered both species of ''Azendohsaurus'' within a clade of azendohsaurids.<ref>{{Cite journal|last1=Pritchard|first1=Adam C.|last2=Gauthier|first2=Jacques A.|last3=Hanson|first3=Michael|last4=Bever|first4=Gabriel S.|last5=Bhullar|first5=Bhart-Anjan S.|date=2018-03-23|title=A tiny Triassic saurian from Connecticut and the early evolution of the diapsid feeding apparatus|journal=Nature Communications |language=En |volume=9 |issue=1 |pages=1213|doi=10.1038/s41467-018-03508-1|issn=2041-1723|pmc=5865133|pmid=29572441|bibcode=2018NatCo...9.1213P}}</ref> The cladogram below follows the results of Sengupta and colleagues in 2017:<ref name="shringadesc">{{cite journal|last1=Sengupta|first1=S.|last2=Ezcurra|first2=M.D.|last3=Bandyopadhyay|first3=S.|date=2017-08-21|title=A new horned and long-necked herbivorous stem-archosaur from the Middle Triassic of India|journal=Scientific Reports|language=En|volume=7|issue=1|pages=8366|doi=10.1038/s41598-017-08658-8|issn=2045-2322|pmc=5567049|pmid=28827583|bibcode=2017NatSR...7.8366S}}</ref>

{{Clade| style=font-size:85%; line-height:80%
|label1=[[Crocopoda]]
|1={{clade
 |1={{clade
  |1=To '''[[Archosauriformes]]''' <span style="{{MirrorH}}">[[File:Deinosuchus riograndensis.png|80px]]</span>[[File:Meyers_grosses_Konversations-Lexikon_-_ein_Nachschlagewerk_des_allgemeinen_Wissens_(1908)_(Antwerpener_Breiftaube).jpg|30px]]
  |state1=dashed
  |2='''[[Rhynchosauria]]''' [[File:Hyperodapedon BW2 white background.jpg|80px]] }}
 |label2=[[Allokotosauria]]
 |2={{clade
  |label1=[[Trilophosauridae]]
  |1={{clade
   |1=''[[Teraterpeton hrynewichorum]]''
   |2={{clade
    |1=''[[Trilophosaurus buettneri]]'' [[File:Trilophosaurus_buettneri_(flipped).jpg|80px]]
    |2=''[[Spinosuchus caseanus]]'' ( = "Trilophosaurus" ''jacobsi'') }} }}
  |label2=[[Azendohsauridae]]
  |2={{clade
   |1=''[[Pamelaria dolichotrachela]]''
   |2={{clade
    |1=''[[Shringasaurus|Shringasaurus indicus]]'' [[File:Shringasaurus_indicus_reconstruction.png|60px]]
    |2={{clade
     |1='''''Azendohsaurus laaroussii'''''
     |2='''''Azendohsaurus madagaskarensis''''' }} }} }} }} }} }}

A 2022 phylogenetic analysis supported a monophyletic Allokotosauria and confirmed that ''Azendohsaurus'' was a sister taxon of ''Shringasaurus'', and that the clade consisting of the two genera was in turn most closely related to ''Malerisaurus'' and ''Pamelaria''.<ref>{{cite journal |last1=Sengupta |first1=Saradee |last2=Bandyopadhyay |first2=Saswati |date=21 February 2022 |title=The osteology of Shringasaurus indicus, an archosauromorph from the Middle Triassic Denwa Formation, Satpura Gondwana Basin, Central India |url=https://www.tandfonline.com/doi/full/10.1080/02724634.2021.2010740 |journal=Journal of Vertebrate Paleontology |volume=41 |issue=5 |doi=10.1080/02724634.2021.2010740 |s2cid=247038160 |access-date=26 March 2022|url-access=subscription }}</ref>

{{Clade| style=font-size:85%; line-height:80%
|label1=[[Allokotosauria]]
|1={{clade
 |label1=Trilophosauridae
 |1={{clade
  |1=''[[Teraterpeton hrynewichorum]]''
  |2={{clade
   |1=''[[Spinosuchus]]'' combined
   |2=''[[Trilophosaurus buettneri]]''}} }}
 |label2=Azendohsauridae
 |2={{clade
  |1=''[[Pamelaria dolichotrachela]]''
  |2=''[[Malerisaurus robinsonae]]''
  |3={{clade
   |1=''[[Shringasaurus|Shringasaurus indicus]]''
   |2={{clade
    |1=''[[Azendohsaurus laaroussi]]''
    |2=''[[Azendohsaurus madagaskarensis]]''}} }} }} }} }}

=== Evolutionary significance ===
{{Multiple image
| align = right
| direction = vertical
| width = 220
| image1 = Saturnalia NT small.jpg
| image2 = Plateosaurus Skelett 2.jpg
| footer = Compared with ''[[Saturnalia tupiniquim|Saturnalia]]'' (top), ''Azendohsaurus'' was more similar to the larger, later [[Sauropodomorpha|sauropodomorphs]] like ''[[Plateosaurus engelhardti|Plateosaurus]]'' (bottom) }}

The number of convergent traits shared between ''Azendohsaurus'' and sauropodomorph dinosaurs is remarkably high, especially as all the shared features are interpreted as being [[Homoplasy|homoplastic]], meaning that they evolved completely independently of each other.<ref name="nesbitt2015" /> Some of the shared adaptations of the skeleton between ''Azendohsaurus'' and sauropodomorphs were previously considered to be unique to sauropodomorphs. However, the [[convergent evolution]] of these traits in ''Azendohsaurus'' as adaptations towards a herbivorous lifestyle show that they may be more broadly distributed amongst Triassic archosauromorphs, and do not necessarily indicate a close relationship to sauropodomorphs in fossil taxa.<ref name="Fetal08" />

The pattern of convergences in ''Azendohsaurus'' is unusual, as they appear to have arisen in only the front half of the animal, while the sprawling back legs and short tail of ''Azendohsaurus'' are characteristically primitive of earlier archosauromorphs, very unlike the columnar hind limbs and long tail of sauropodomorphs.<ref name="Fetal10" /> This further highlights the non-uniform distribution and acquisition of typically sauropodomorph traits in other herbivorous archosauromorphs.<ref name="nesbitt2015"/>

The age of ''Azendohsaurus'' is also significant, as it was roughly coeval with the earliest known sauropodomorphs from [[Carnian]] South America, such as the lightweight, bipedal ''[[Saturnalia tupiniquim|Saturnalia]]''. However, ''Azendohsaurus'' resembles the later [[Norian]] sauropodomorphs more closely, both in general anatomy and its larger body size. This suggests that azendohsaurids had been the first reptiles to evolve as high browsing herbivores in Triassic ecosystems, prior to the evolution of the larger sauropodomorphs, which had previously been assumed to have been the first high browsing herbivores. It also indicates that the convergence between ''Azendohsaurus'' and sauropodomorphs did not occur under the same environmental circumstances, as ''Azendohsaurus'' was part of an initial wave of herbivory in archosauromorphs (along with rhynchosaurs, silesaurids and cynodonts) and large sauropodomorphs in a second wave (along with herbivorous pseudosuchians).<ref name="nesbitt2015" />

''Azendohsaurus'' also demonstrates that archosauromorphs were occupying roles as large herbivores in Triassic ecosystems earlier in their evolutionary history than had been assumed. These roles were previously thought to be dominated by large [[synapsid]]s such as [[dicynodont]]s prior to the radiation of archosaurs in the Late Triassic, but ''Azendohsaurus'' suggests that earlier archosauromorphs were also capable of competing with synapsid herbivores.<ref name="shringadesc" />

==Palaeobiology==

=== Feeding and diet ===
[[File:Azendohsaurus madagaskarensis maxilla and teeth.png|thumb|left|Closeup of implanted teeth and the [[maxilla]] UA 8-29-97-160 of ''A. madagaskarensis'']]
The leaf-shaped teeth of ''Azendohsaurus'' are clearly suited for a herbivorous lifestyle, and microwear—marks left on the tooth surface during feeding—on the teeth of ''A. madagaskarensis'' suggest they were used for browsing on vegetation that was not especially tough or woody, preferring softer (but firm) vegetation. The microwear patterns also show that it used a simple up-and-down motion of the jaw, and did not use complex jaw movement to chew its food like ornithischian dinosaurs or contemporary cynodonts.<ref name=":3" /> This microwear has not yet been observed on the teeth of ''A. laaroussii'', but it is unknown if this is a genuine feature relating to a difference in diet and feeding habits between the two species or if it is just a feature of preservation.<ref name="Fetal10"/>

The fully developed palatal teeth suggest that it was using them for feeding in a specialised manner. However, no functional studies have been performed on the palatal teeth so it is unknown exactly what they were used for, although their similar shape to the marginal teeth suggests they were used for processing similar food. A pterygoid from a younger individual of ''A. madagaskarensis'' has fewer rows of palatal teeth that are smaller in size than those of the larger, mature individuals, indicating that ''Azendohsaurus'' increased both the number and size of its palatal teeth as it grew into adulthood. Younger individuals also had fewer dentary teeth than adults, although the difference was much less extreme compared to the palatal teeth (16 compared to the 17 of mature specimens).<ref name="Fetal10"/><ref name="Fetal08" />

=== Body posture ===
The body posture inferred for ''Azendohsaurus'' is a mixture of sprawled and semi-sprawled. The hind limbs have been interpreted as being completely sprawled outwards from the body, with its femur held straight out and the lower leg bent 90° beneath it at the knee, like a [[lizard]]. The forelimbs and shoulder girdle, however, suggest that the front of the body was held more upright than the hind quarters, with a partly downward directed shoulder socket and a humerus more suited for being held partially erect, and was similar in shape to those of sauropodomorphs. This unusual combination suggests that ''Azendohsaurus'' stood with its front end raised up off from the ground, which combined with its long, arched neck and small head, allowed it to browse relatively high off the ground, unlike contemporary low-browsing rhynchosaurs and cynodonts. Adapting to high-browsing could possibly explain the convergence between ''Azendohsaurus'' and sauropodomorphs, acquiring similar traits of the neck, forelimbs and spine to perform in similar niches. However, the more sprawling posture of ''Azendohsaurus'' probably inhibited high-browsing like that of the fully erect sauropodomorphs.<ref name="nesbitt2015" />

===Palaeopathology===
Despite the multitude of specimens present in the bone bed that was examined, only a single [[pathology]] has been recorded in ''A. madagaskarensis''. Specimen UA 7-16-99-620, one of the three preserved interclavicles, had been malformed so that the long posterior process had been sharply bent to the right, compared to the normal straight posterior processes of the other two interclavicles.<ref name="nesbitt2015"/>

===Metabolism and growth===
In 2019, thin slices were cut from the humerus, femur and tibia of specimens attributed to ''A. laaroussii'' for [[histological]] examination of the microscopic bone structure to try and determine the rate of growth in ''Azendohsaurus''. The vascular density (the density of blood vessels in the bone tissue) in all three limb bones was found to be comparable to those of fast-growing [[birds]] and [[mammals]], and the types of bone tissue identified—particularly energy-consuming fibrolamellar bone tissue—were interpreted as indicating a high [[resting metabolic rate]] that was in the range of living birds and mammals. It was inferred then that, like birds and mammals, ''Azendohsaurus'' would also likewise have been [[endothermic]], or "warm-blooded". High resting metabolic rates similar to those of ''Azendohsaurus'' had been identified in other more derived archosauromorphs (such as ''[[Prolacerta]]''), and analyses suggested that endothermy may then have been ancestrally present in archosauromorphs as far back as their common ancestor with allokotosaurs. This suggests that ''Azendohsaurus'' may then have been ancestrally endothermic.<ref name="Therm">{{cite journal |last1=Cubo |first1=J. |last2=Jalil |first2=N.-E. |year=2019 |title=Bone histology of ''Azendohsaurus laaroussii'': Implications for the evolution of thermometabolism in Archosauromorpha |journal=[[Paleobiology (journal)|Paleobiology]] |volume=45 |issue=2 |pages=317–330 |doi=10.1017/pab.2019.13|s2cid=155782789 |url=https://hal.sorbonne-universite.fr/hal-02969492/file/Cubo%20et%20Jalil%20-%202019%20-%20Bone%20histology%20of%20Azendohsaurus%20laaroussii%20Implic.pdf }}</ref> By contrast, the related allokotosaur ''Trilophosaurus'' was previously found to not have any fibrolamellar bone tissue in its limb bones and so was inferred to have grown slowly.<ref>{{cite journal |last1=Werning |first1=S. |last2=Irmis |first2=R. |year=2010 |title=Reconstructing the ontogeny of the Triassic basal archosauromorph ''Trilophosaurus'' using bone histology and limb bone morphometrics |url=http://vertpaleo.org/Annual-Meeting/Future-Past-Meetings/MeetingPdfs/2010AnnualMeetingAbstracts.aspx |journal=[[Journal of Vertebrate Paleontology]] |volume=30 |issue=Supp. 2: 70th Anniversary Meeting Society Of Vertebrate Paleontology |pages=185A–186A |doi=10.1080/02724634.2010.10411819 |s2cid=220429286 |access-date=2019-07-19 |archive-date=2019-08-20 |archive-url=https://web.archive.org/web/20190820214002/http://vertpaleo.org/Annual-Meeting/Future-Past-Meetings/MeetingPdfs/2010AnnualMeetingAbstracts.aspx |url-status=dead |url-access=subscription }}</ref>

==Palaeoecology==
Although the two species of ''Azendohsaurus'' are known from disparate locations in North Africa and Madagascar, during the Middle to Late Triassic these regions were connected as part of the [[supercontinent]] [[Pangaea]]. Because of this, the two regions share broadly similar faunas, as well as sharing some with other regions of the globe at the time. For example, the cynodonts in Madagascar are similar to those also found in South America, and the Moroccan temnospondyls may be related to those found in eastern North America.<ref name=Melo15/><ref>{{cite journal |last1=Gee |first1=B.M. |last2=Paerker |first2=W.G. |last3=Marsh |first3=A.D. |year=2020 |title=Redescription of ''Anaschisma'' (Temnospondyli: Metoposauridae) from the Late Triassic of Wyoming and the phylogeny of the Metoposauridae |journal=[[Journal of Systematic Palaeontology]] |volume=18 |issue=3 |pages=233–258 |doi=10.1080/14772019.2019.1602855 |s2cid=190896742 |url=https://digitalcommons.unl.edu/natlpark/197 |archive-date=2020-08-18 |access-date=2020-09-06 |archive-url=https://web.archive.org/web/20200818111933/https://digitalcommons.unl.edu/natlpark/197/ |url-status=live |url-access=subscription }}</ref> The climate was hot and dry at this time, but with evidence suggesting higher levels of rainfall during the Carnian, interrupting the increasing aridity trend and creating wetter environments around the globe.<ref>{{cite journal |last1=Ruffell |first1=A. |last2=Simms |first2=M.J. |last3=Wignell |first3=P.B. |year=2016 |title=The Carnian Humid Episode of the late Triassic: a review |journal=[[Geological Magazine]] |volume=153 |issue=Special Issue 2 |pages= 271–284 |doi=10.1017/S0016756815000424 |url=http://eprints.whiterose.ac.uk/90239/1/Carnian%20humidity%20final%20version.pdf|bibcode=2016GeoM..153..271R |s2cid=128596906 }}</ref>

[[File:Moghreberia.jpg|thumb|Life illustration of the Moroccan dicynodont ''[[Moghreberia]]'']]

===Timezgadiouine Formation, Morocco===
Other reptiles from the base of the Irohalene (T5) member of the [[Timezgadiouine Formation]] contemporaneous with ''A. laaroussii'' include the [[phytosaur]] ''[[Arganarhinus]]'',<ref>{{Cite journal|last=Dutuit|first=Jean-Michel|date=1977|title=Paleorhinus magnoculus, Phytosaure du Trias supérieur de l'Atlas marocain|journal=Géologie Méditerranéenne|language=fr-FR|volume=4|issue=3|pages=255–267|doi=10.3406/geolm.1977.1007|issn=0397-2844|doi-access=free}}</ref> the predatory [[Rauisuchidae|rauisuchid]] ''[[Arganasuchus]]'',<ref>{{Cite journal|last1=Jalil|first1=Nour-Eddine|last2=Peyer|first2=Karin|date=2007|title=A new Rauisuchian (Archsauria, Suchia) from the Upper Triassic of the Argana Basin, Morocco|journal=Palaeontology|language=en|volume=50|issue=2|pages=417–430|doi=10.1111/j.1475-4983.2007.00640.x|issn=0031-0239|doi-access=free}}</ref> the herbivorous [[Silesauridae|silesaurid]] ''[[Diodorus scytobrachion|Diodorus]]'',<ref name=":7">{{Cite journal|last1=Kammerer|first1=Christian F.|last2=Nesbitt|first2=Sterling J.|last3=Shubin|first3=Neil H.|date=2012|title=The First Silesaurid Dinosauriform from the Late Triassic of Morocco|url=http://www.app.pan.pl/archive/published/app57/app20110015.pdf|journal=Acta Palaeontologica Polonica|language=en|volume=57|issue=2|pages=277–284|doi=10.4202/app.2011.0015|s2cid=55015883|issn=0567-7920|doi-access=free|archive-date=2024-12-09|access-date=2019-07-19|archive-url=https://web.archive.org/web/20241209140420/https://app.pan.pl/archive/published/app57/app20110015.pdf|url-status=live}}</ref> a [[Paratypothoracisini|paratypothoracisine]] [[aetosaur]],<ref name="longo">{{Cite journal|last=Lucas|first=Spencer G.|date=1998|title=The aetosaur ''Longosuchus'' from the Triassic of Morocco and its biochronological significance |journal=Comptes Rendus de l'Académie des Sciences, Série IIA  |volume=326 |issue=8|pages=589–594|doi=10.1016/s1251-8050(98)80211-5|issn=1251-8050|bibcode=1998CRASE.326..589L}}</ref><ref>{{Cite journal|last1=Parker|first1=William G.|last2=Martz|first2=Jeffrey W.|date=2010-07-14|title=Using positional homology in aetosaur (Archosauria: Pseudosuchia) osteoderms to evaluate the taxonomic status of ''Lucasuchus hunti'' |journal=Journal of Vertebrate Paleontology|language=en|volume=30|issue=4|pages=1100–1108|doi=10.1080/02724634.2010.483536|s2cid=83713904|issn=0272-4634}}</ref> and [[procolophonid]] [[parareptile]]s,<ref name=":4"/> as well as the [[Stahleckeriidae|stahleckeriid]] dicynodont ''[[Moghreberia]]'', a synapsid.<ref name=":6" /> [[Temnospondyli|Temnospondyl]] [[amphibian]]s are represented by several genera of [[Metoposauroidea|metoposauroids]], including the [[Metoposauridae|metoposaurids]] ''[[Arganasaurus]]'' and ''[[Dutuitosaurus]],'' and the [[Latiscopidae|latiscopid]] ''[[Almasaurus]]''.<ref name=":2" /> Fish are also known from the T5 member, including various ray-finned [[Actinopterygii|actinopterygians]] such as the locally endemic ''[[Dipteronotus|Dipteronotus gibbosus]]'' and ''[[Mauritanichthys]]'', as well as other [[Perleidiformes|perleidiform]] and [[Redfieldiiformes|redfieldiiform]] fishes, alongside [[Lobe finned fish|lobe-finned]] [[actinistia]]ns and [[lungfish]] such as ''[[Asiatoceratodus]]''.<ref name=Jalil99/><ref name="longo"/><ref>{{cite journal|last=Martin |first=M. |date=1980 |title=''Mauritanichthys rugosus'' n. gen. et n. sp., Redfieldiidae (Actinopterygi, Chondrostei) du Trias Superieur continental marocain [''Mauritanichthys rugosus'' n. gen. et n. sp., Redfieldiidae (Actinopterygi, Chondrostei) from the continental Moroccan Upper Triassic] |journal=[[Geobios|Géobios]] |volume=13 |issue=3 |pages=437–441 |doi=10.1016/S0016-6995(80)80078-7}}</ref><ref>{{cite journal|last=Martin |first=M. |date=1980 |title=''Dipteronotus gibbosus'' (Actinopterygi, Chondrostei), nouveau Colobodontidae du Trias Superieur continental marocain [''Dipteronotus gibbosus'' (Actinopterygi, Chondrostei), new Colobodontidae from the continental Moroccan Upper Triassic] |journal=[[Geobios|Géobios]] |volume=13 |issue=3 |pages=445–449 |doi=10.1016/S0016-6995(80)80080-5}}</ref><ref>{{cite journal|last=Martin |first=M. |date=1982 |title=Les Actinoptérygiens (Perleidifomes et Redfieldiiformes) du Trias supérieur continental du couloir d'Argana (Atlas occidental, Maroc) [The actinopterygians (Perleidiformes and Redfieldiiformes) from the continental Upper Triassic of the Argana valley (western Atlas, Morocco)] |journal=[[Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen]] |volume=162 |issue=3 |pages=352–372}}</ref>

The T5 member is composed of cyclical layers of [[Bioturbation|bioturbated]] [[mudstone]] and [[sandstone]] deposited in a broad, semi-humid basin.<ref name=":8">{{Cite journal|last1=Baudon|first1=Catherine|last2=Redfern|first2=Jonathan|last3=Van Den Driessche|first3=Jean|date=2012-04-09|title=Permo-Triassic structural evolution of the Argana Valley, impact of the Atlantic rifting in the High Atlas, Morocco|url=https://www.academia.edu/11210616|journal=Journal of African Earth Sciences|language=en|volume=65|pages=91–104|doi=10.1016/j.jafrearsci.2012.02.002|issn=1464-343X}}</ref> It has been interpreted as a system of brackish permanent lakes and sandbars, or alternatively sandy [[meandering rivers]] on a muddy floodplain. The fluvial or lacustrine sediments of the T5 member contrast with the [[Dry lake|playa]] sediments of the preceding T4 member, suggesting that it was deposited during an interval of increased rainfall.<ref name=":52">{{Cite journal|last=Brown|first=Roy H.|date=1980-07-01|title=Triassic Rocks of Argana Valley, Southern Morocco, and Their Regional Structural Implications|url=https://doi.org/10.1306/2F919418-16CE-11D7-8645000102C1865D|journal=AAPG Bulletin|volume=64|issue=7|pages=988–1003|doi=10.1306/2F919418-16CE-11D7-8645000102C1865D|issn=0149-1423|url-access=subscription}}</ref><ref>{{Cite journal |last1=Hofmann |first1=Axel |last2=Tourani |first2=Abdelilah |last3=Gaupp |first3=Reinhard |date=2000 |title=Cyclicity of Triassic to Lower Jurassic continental red beds of the Argana Valley, Morocco: implications for palaeoclimate and basin evolution |url=https://www.academia.edu/7569221 |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |volume=161 |issue=1–2 |pages=229–266 |doi=10.1016/s0031-0182(00)00125-5 |issn=0031-0182 |bibcode=2000PPP...161..229H |archive-date=2021-12-23 |access-date=2019-07-19 |archive-url=https://web.archive.org/web/20211223213802/https://www.academia.edu/7569221 |url-status=live }}</ref>

Numerous tracks and trackways from various animals are preserved, typically those of animals known from fossil remains such as phytosaurs, pseudosuchians, [[Dinosauromorpha|dinosauromorphs]] and basal archosauromorphs. The tracks also appear to indicate the presence of large to very-large dinosauromorphs or [[Paracrocodylomorpha|paracrocodylomorphs]] that are currently not yet known from skeletal remains. Additional traces mark the presence of burrowing invertebrates, [[Bivalvia|bivalves]], and [[clam shrimp]]s.<ref>{{Cite journal |last1=Lagnaoui |first1=A. |last2=Klein |first2=H. |last3=Voigt |first3=S. |last4=Hminna |first4=A. |last5=Saber |first5=H. |last6=Schneider |first6=J.W. |last7=Werneburg |first7=R. |date=2012 |title=Late Triassic Tetrapod-Dominated Ichnoassemblages from the Argana Basin (Western High Atlas, Morocco) |url=https://www.researchgate.net/publication/234033566 |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=19 |issue=4 |pages=238–253 |doi=10.1080/10420940.2012.718014|s2cid=128885921 }}</ref><ref>{{Cite journal |last1=Lagnaoui |first1=A. |last2=Klein |first2=H. |last3=Saber |first3=H. |last4=Fekkak |first4=A. |last5=Belahmira |first5=A. |last6=Schneider |first6=J.W. |date=2016 |title=New discoveries of archosaur and other tetrapod footprints from the Timezgadiouine Formation (Irohalene Member, Upper Triassic) of the Argana Basin, western High Atlas, Morocco – Ichnotaxonomic implications |url=https://www.researchgate.net/publication/301550793 |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=453 |pages=1–9 |doi=10.1016/j.palaeo.2016.03.022|bibcode=2016PPP...453....1L }}</ref><ref>{{Cite journal |last1=Zouheir |first1=Tariq |last2=Hminna |first2=Abdelkbir |last3=Klein |first3=Hendrik |last4=Lagnaoui |first4=Abdelouahed |last5=Saber |first5=Hafid |last6=Schneider |first6=Joerg W. |date=2018 |title=Unusual archosaur trackway and associated tetrapod ichnofauna from Irohalene member (Timezgadiouine formation, late Triassic, Carnian) of the Argana Basin, Western High Atlas, Morocco |url=https://www.researchgate.net/publication/327298375 |journal=Historical Biology |volume=32 |issue=5 |language=en |pages=589–601 |doi=10.1080/08912963.2018.1513506|s2cid=91315646 |issn=0891-2963}}</ref>

===Makay Formation, Madagascar===
In Madagascar, ''Azendohsaurus'' co-existed with the [[Hyperodapedontinae|hyperodapedontine]] rhynchosaur ''Isalorhynchus'',<ref name=rhynch>{{Cite journal |last1=Langer |first1=Max |last2=Boniface |first2=Michael |last3=Cuny |first3=Gilles |last4=Barbieri |first4=Laurent |date=2000 |title=The phylogenetic position of ''Isalorhynchus genovefae'', a Late Triassic rhynchosaur from Madagascar |url=http://www.paleolab.com.br/assets/uploads/files/pdf/Langer_et_al_2000a.pdf |journal=Annales de Paléontologie|volume=86|issue=2|pages=101–127|doi=10.1016/s0753-3969(00)80002-6|issn=0753-3969}}</ref> the herbivorous traversodontid cynodonts ''[[Dadadon]]'' and ''[[Menadon]]'', and the predatory [[chiniquodontid]] cynodont ''[[Chiniquodon kalanoro]]'',<ref name="Chiniq">{{cite journal |last1=Kammerer |first1=C.F. |last2=Flynn |first2=J.J. |last3=Ranivoharimanana |first3=L. |last4=Wyss |first4=A.R. |year=2010 |title=The First Record of a Probainognathian (Cynodontia: Chiniquodontidae) from the Triassic of Madagascar |journal=Journal of Vertebrate Paleontology |volume=30 |issue=6 |pages=1889–1894 |doi=10.1080/02724634.2010.520784|s2cid=85868922 }}</ref> as well as an undescribed [[Kannemeyeriiformes|kannemeyeriiform]] dicynodont, a [[sphenodont]]ian reptile,<ref name="Fetal08" /> a [[procolophonid]] [[parareptile]],<ref name=rhynch/> the diminutive [[lagerpetid]] ''[[Kongonaphon]]'',<ref>{{Cite journal|last1=Kammerer|first1=Christian F.|last2=Nesbitt|first2=Sterling J.|last3=Flynn|first3=John J.|last4=Ranivoharimanana|first4=Lovasoa|last5=Wyss|first5=André R.|date=2020-07-02|title=A tiny ornithodiran archosaur from the Triassic of Madagascar and the role of miniaturization in dinosaur and pterosaur ancestry|journal=Proceedings of the National Academy of Sciences|volume=117|issue=30|pages=17932–17936|language=en|doi=10.1073/pnas.1916631117|pmid=32631980|pmc=7395432|issn=0027-8424|doi-access=free }}</ref> various other undescribed dinosauromorphs, and an "enigmatic archosaur" of uncertain classification.<ref name="nesbitt2015" /> The faunal composition of the Isalo II is believed to represent a Middle Triassic [[Ladinian]] aged assemblage, existing prior to the appearance of dinosaurs and associated Late Triassic faunas, particularly [[aetosaur]]s and [[phytosaur]]s that are absent from the formation,<ref name="Fetal10" /> and also inferred from the dominance of traversodonts in the fauna.<ref name="Chiniq"/><ref>{{Cite journal|last=Langer|first=Max Cardoso|date=2005|title=Studies on continental Late Triassic tetrapod biochronology. II. The Ischigualastian and a Carnian global correlation|journal=Journal of South American Earth Sciences|volume=19|issue=2|pages=219–239|doi=10.1016/j.jsames.2005.04.002|issn=0895-9811|bibcode=2005JSAES..19..219L|url=http://doc.rero.ch/record/232971/files/PAL_E4557.pdf|archive-date=2023-11-14|access-date=2019-10-20|archive-url=https://web.archive.org/web/20231114235305/http://doc.rero.ch/record/232971/files/PAL_E4557.pdf|url-status=live}}</ref> However, this age assessment remains uncertain, and the formation is possibly from the younger early Late Triassic during the Carnian, as has been proposed for the T5 member of the Argana Formation.<ref name="nesbitt2015" /><ref name=":5"/>

Fossils of ''A. madagaskarensis'' have been exclusively recovered from a deposit of fine grained red mudstone, while other fossil bearing localities in the formation consist of medium grained channel sands, possibly reflecting a habitat preference in the ecosystem distinct from other animals or unique behavioural trait. The absence of any other species in the bone bed may also support this. However, this speculation cannot be confirmed, and it could instead be attributed to [[preservation bias]].<ref name="nesbitt2015" />

Possible niche partitioning in diet, though, is supported by differences in the tooth microwear of ''A. madagaskarensis'' and the contemporary traversodont ''Dadadon''. ''Dadadon'' was inferred to be capable of feeding on tough, hardy vegetation by using complex chewing, in contrast to the simpler dentition and processing of ''Azendohsaurus'', which was better suited for eating leaves.<ref name=":3">{{Cite journal|last1=Goswami|first1=A.|last2=Flynn|first2=J.J.|last3=Ranivoharimanana|first3=L.|last4=Wyss|first4=A.R.|date=2005|title=Dental microwear in Triassic amniotes: implications for paleoecology and masticatory mechanics.|url=https://www.researchgate.net/publication/228659761|journal=Journal of Vertebrate Paleontology|volume=25|issue=2|pages=320–329|doi=10.1671/0272-4634(2005)025[0320:DMITAI]2.0.CO;2|s2cid=85754777 }}</ref> This may also be supported by its more elevated body posture and long neck.<ref name="nesbitt2015" />

==References==
{{Reflist}}

{{Allokotosauria|R.}}
{{Taxonbar|from=Q2294166}}
{{Portal bar|Paleontology|Reptiles|Morocco|Madagascar}}

[[Category:Azendohsauridae]]
[[Category:Prehistoric reptile genera]]
[[Category:Middle Triassic reptiles of Africa]]
[[Category:Late Triassic reptiles of Africa]]
[[Category:Fossils of Morocco]]
[[Category:Fossils of Madagascar]]
[[Category:Triassic Madagascar]]
[[Category:Fossil taxa described in 1972]]