{{short description|Order of reptiles}} {{Use dmy dates|date=September 2023}} {{Automatic taxobox | name = Phytosaurs | fossil_range = Ladinian – Rhaetian, {{fossil range|242|201.4|earliest=247|latest=199}} Possible ghost lineage from the Middle Triassic<ref>{{cite web |title=Phytosauria: The phytosaurs |url=https://ucmp.berkeley.edu/taxa/verts/archosaurs/phytosauria.php |website=University of California Museum of Paleontology |publisher=Matt Wedel |access-date=20 June 2022 |ref=33}}</ref> Possible Early Jurassic (Hettangian) records <ref name=Maisch2010>{{cite journal |last=Maisch |first=M.W. |author2=Kapitzke, M. |year=2010 |title=A presumably marine phytosaur (Reptilia: Archosauria) from the pre-planorbis beds (Hettangian) of England |journal=Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen |volume=257 |issue=3 |pages=373–379 |doi=10.1127/0077-7749/2010/0076}}</ref> | image = Redondasaurus bermani at CMNH 04 white background.jpg | image_upright = 1.2 | image_caption = Skeleton of ''Redondasaurus'' at the Carnegie Museum of Natural History | display_parents = 2 | taxon = Phytosauria | authority = von Meyer, 1861 | subdivision_ranks = Subgroups | subdivision = *{{extinct}}''Centemodon''? *{{extinct}}''Clepsysaurus''? *{{extinct}}''Diandongosuchus'' *{{extinct}}''Mesorhinosuchus'' *{{extinct}}''Omosaurus''? *{{extinct}}Parasuchidae {{Collapse top|title=Phytosauria ''incertae sedis''|left=yes|padding=0|border=0|border2=0|bg=clear|bg2=clear}} *{{extinct}}''Belodon'' *{{extinct}}''Calamosuchus'' *{{extinct}}''Compsosaurus'' *{{extinct}}''Francosuchus''? *{{extinct}}''Parrishia''? *{{extinct}}''Phytosaurus'' *{{extinct}}''Termatosaurus''? {{Collapse bottom}} | synonyms = Parasuchia <small>Huxley, 1875</small> }}
'''Phytosaurs''' (Φυτόσαυροι in Greek, meaning 'plant lizard') are an extinct group of large, mostly semiaquatic Late Triassic archosauriform or basal archosaurian reptiles. Phytosaurs belong to the order '''Phytosauria''' and are sometimes referred to as '''parasuchians'''. Phytosauria, Parasuchia, Parasuchidae, and Phytosauridae have often been considered equivalent groupings containing the same species. Some recent studies have offered a more nuanced approach, defining Parasuchidae and Phytosauridae as nested clades within Phytosauria as a whole. The clade Phytosauria was defined by Paul Sereno in 2005 as ''Rutiodon carolinensis'' and all taxa more closely related to it than to ''Aetosaurus ferratus'', ''Rauisuchus tiradentes'', ''Prestosuchus chiniquensis'', ''Ornithosuchus woodwardi'', or ''Crocodylus niloticus'' (the Nile crocodile).<ref name="NSJ11">{{cite journal|last=Nesbitt|first=S.J.|year=2011|title=The early evolution of archosaurs: relationships and the origin of major clades|journal=Bulletin of the American Museum of Natural History|volume=352|pages=1–292|doi=10.1206/352.1|hdl=2246/6112|s2cid=83493714|doi-access=free}}</ref> Phytosaurs were long-snouted and heavily armoured, bearing a remarkable resemblance to modern crocodilians in size, appearance, and lifestyle, as an example of convergence or parallel evolution.
The name ''phytosaur'' means {{Gloss|plant lizard}}, as the first fossils of phytosaurs were mistakenly thought to belong to plant-eaters.<ref>{{cite book |last1=Colbert |first1=Edwin H. (Edwin Harris) |last2=Knight |first2=Charles Robert |title=The dinosaur book: the ruling reptiles and their relatives |date=1951 |publisher=McGraw-Hill |location=New York |page=152 |url=https://archive.org/details/bookruli00colb/page/152/mode/2up}}</ref>
For many years, phytosaurs were considered to be the most basal group of Pseudosuchia (crocodile-line archosaurs), meaning that they were thought to be more closely related to the crocodilians than to birds (the other living group of archosaurs). Some studies of the evolutionary relationships of early archosauriforms have suggested that phytosaurs evolved before the split between crocodile- and bird-line archosaurs and are a sister taxon of Archosauria. The most recent study retains the former way of classifying phytosaurs as pseudosuchians.<ref>{{cite journal |last1=Jones |first1=Andrew S. |last2=Butler |first2=Richard J. |title=A new phylogenetic analysis of Phytosauria (Archosauria: Pseudosuchia) with the application of continuous and geometric morphometric character coding |journal=PeerJ |date=10 December 2018 |volume=6 |article-number=e5901 |doi=10.7717/peerj.5901|pmid=30581656 |pmc=6292387 |doi-access=free }}</ref>
Phytosaurs had a nearly global distribution during the Triassic. Fossils have been recovered from Europe, North America, India, Morocco, Thailand, Brazil, Greenland<ref>Mateus, O., Clemmensen L., Klein N., Wings O., Frobøse N., Milàn J., Adolfssen J., & Estrup E. (2014). The Late Triassic of Jameson Land revisited: new vertebrate findings and the first phytosaur from Greenland. Journal of Vertebrate Paleontology. Program and Abstracts, 2014, 182.</ref> and Madagascar. Fossils attributed to phytosaurs have been found in Early Jurassic rocks, possibly extending their temporal range beyond the Triassic-Jurassic boundary.<ref name=Maisch2010>{{cite journal |last=Maisch |first=M.W. |author2=Kapitzke, M. |year=2010 |title=A presumably marine phytosaur (Reptilia: Archosauria) from the pre-planorbis beds (Hettangian) of England |journal=Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen |volume=257 |issue=3 |pages=373–379 |doi=10.1127/0077-7749/2010/0076}}</ref> They may have also been present in rock layers dating to the Middle Triassic of China as evidenced by ''Diandongosuchus'', however it is not known if this is truly a member of the clade.
==Description== [[File:Smilosuchus-reconstructions-Jeff-Martz-600-px-tiny-Oct-2014-Tetrapod-Zoology.jpg|thumb|Illustration of two ''Smilosuchus'' species, illustrating brachyrostral and dolichorostral snout types]] Phytosaurs are known from many different morphologies, specifically with vastly different skull forms. These changes relate to the feeding and habits of the animals, not completely evolutionary modifications. Dolichorostral ({{Gloss|long-snouted}}) phytosaurs have a long, slender snout with many conical teeth that are homodont (all the same). These taxa were most likely piscivores that were well adapted to capture fast aquatic prey, but not terrestrial animals. ''Paleorhinus'', ''Rutiodon'' and ''Mystriosuchus'' are dolichorostral phytosaurs, but do not form a distinct group of taxa (named Mystriosuchinae of Friedrich von Huene) as other morphotypes such as ''Pseudopalatus'' are more closely related to ''Mystriosuchus'' than it is to the other long-snouted taxa. Brachyrostral ({{Gloss|short-snouted}}) forms are the opposite, having a massive, broad snout, and very strong skulls and jaws. They are heterodont, as the front teeth are prominent fangs, and the rear teeth are blade-like for slicing food into chunks that can be swallowed easily. Taxa like this, such as ''Nicrosaurus'' and ''Smilosuchus'', were powerful taxa that fed on stronger prey, such as terrestrial animals that came to the water to drink. Altirostral ({{Gloss|high-snouted}}) animals are intermediate between the two distinct types. They had heterodont dentition but not as extremely developed as the brachyrostral type. ''Pseudopalatus'' is an altirostral phytosaur, and was most likely a generalist feeder. Modern crocodilians exhibit a similar morphological diversity, for example the broad snouted altirostral alligator and the long snouted dolichorostral gavial.<ref name=h02/>
Various phytosaurs have crests and similar ornamentations in their snouts. ''Nicrosaurus'' has a ridge along the snout that would have supported a keratinous crest in life, while ''Mystriosuchus westphali'' has several bony crests.<ref name=h02>{{cite journal|last=Hungerbühler|first=A|year=2002|title=The Late Triassic phytosaur ''Mystriosuchus westphali'', with a revision of the genus|journal=Palaeontology|volume=45|issue=2|pages=377–418|doi=10.1111/1475-4983.00242|bibcode=2002Palgy..45..377H|doi-access=free}}</ref>
===Differences from crocodiles=== {{One source|date=January 2026|section}} Despite their great similarities in appearance and lifestyle, there are still a number of minor differences that distinguish phytosaurs from true crocodiles. For one thing, the phytosaur ankle structure is much more primitive than that of any crocodile. Also, phytosaurs lack the true bony secondary palate that enables crocodiles to strengthen their skulls and breathe even when their mouths are full of water. However, phytosaurs do possess a somewhat analogous structure that is derived from the ventral part of the extremely elongated premaxillae (a premaxillary palate), which works to displace the internal nasal openings (choanae) backwards, although the external nares being positioned far back on the top skull helps to bring the choanae back by itself in the first place, resulting in the premaxillary palate not being able to act as a partition between the nasal and buccal cavities in some genera such as Ebrachiosuchus, although still acting to strengthen the skull.<ref>{{Cite web |title=(PDF) Comparative biomechanical analysis demonstrates functional convergence between slender-snouted crocodilians and phytosaurs |url=https://www.researchgate.net/publication/330295815_Comparative_biomechanical_analysis_demonstrates_functional_convergence_between_slender-snouted_crocodilians_and_phytosaurs |archive-url=https://web.archive.org/web/20250918191350/https://www.researchgate.net/publication/330295815_Comparative_biomechanical_analysis_demonstrates_functional_convergence_between_slender-snouted_crocodilians_and_phytosaurs |archive-date=18 September 2025 |access-date=2026-01-27 |website=ResearchGate |language=en |url-status=live }}</ref> In life, it is possible that phytosaurs had a fleshy palate in addition to the premaxillary palate, which would help complete the separation between the aforementioned nasal and oral cavities. Phytosaurs were even better armoured than crocodiles, protected by heavy bony scutes (often found as fossils), and the belly reinforced with a dense arrangement of gastralia (abdominal ribs). Finally, and most noticeably, phytosaurs had nostrils placed near or above the level of the eyes, in contrast to crocodiles where the nostrils are near the end of the snout. This adaptation may have developed to allow them to breathe while the rest of the body was submerged.{{Citation needed|date=January 2026}}
===Teeth=== Unlike most crocodilians, phytosaurs have tooth serrations.<ref>{{cite journal |last1=Stocker |first1=Michelle R. |last2=Butler |first2=Richard J. |title=Phytosauria |journal=Geological Society, London, Special Publications |date=2013 |volume=379 |issue=1 |pages=91–117 |doi=10.1144/SP379.5|bibcode=2013GSLSP.379...91S |s2cid=219192243 }}</ref>
In a 2001 study of the biomechanics of the dinosaur ''Albertosaurus''<nowiki>'</nowiki>s teeth, William L. Abler also examined a phytosaur's teeth, finding that it has had serrations so fine that they resembled a crack in the tooth.<ref name="alberto-tooth-abs-84" /> ''Albertosaurus'' had similarly crack-like serrations, but, at the base of each serration Abler discovered a round void, which would have functioned to distribute force over a larger surface area.<ref name="alberto-tooth-abs-84" /> This void, termed an ampulla, would hinder the ability of the "crack" formed by the serration to propagate through the tooth.<ref name="alberto-tooth-abs-84" /> The phytosaur was found to lack adaptations for preventing its dental "cracks" from propagating.<ref name="alberto-tooth-abs-84" /> Abler examined another sort of prehistoric predator, ''Dimetrodon'', and found that it also lacked adaptations for guarding against crack propagation.<ref name="alberto-tooth-abs-84" /> Based on their teeth, most phytosaur genera are carnivorous, piscivorous, or a combination of the two. However, two taxa show slight adaptations towards hunting and consuming harder invertebrates.<ref>{{Cite journal|url=https://onlinelibrary.wiley.com/doi/10.1111/pala.12515|doi=10.1111/pala.12515|issn=0031-0239 |title=Dietary constraints of phytosaurian reptiles revealed by dental microwear textural analysis|year=2021|last1=Bestwick|first1=Jordan|last2=Jones|first2=Andrew S.|last3=Purnell|first3=Mark A.|last4=Butler|first4=Richard J.|journal=Palaeontology|volume=64|issue=1 |pages=119–136|bibcode=2021Palgy..64..119B |s2cid=229504989|doi-access=free}}</ref>
A study on phytosaur microwear patterns has found ''Mystriosuchus'' to line with soft invertebrate consumers, ''Nicrosaurus'' with hard invertebrate consumers and ''Smilosuchus'' and ''Machaeroprosopus'' with carnivores and piscivores.<ref>{{Cite journal|url=https://onlinelibrary.wiley.com/doi/10.1111/pala.12515|doi=10.1111/pala.12515|issn=0031-0239|title=Dietary constraints of phytosaurian reptiles revealed by dental microwear textural analysis|year=2021|last1=Bestwick|first1=Jordan|last2=Jones|first2=Andrew S.|last3=Purnell|first3=Mark A.|last4=Butler|first4=Richard J.|journal=Palaeontology|volume=64|issue=1 |pages=119–136|bibcode=2021Palgy..64..119B |s2cid=229504989|doi-access=free}}</ref>
===Locomotion and terrestriality=== Phytosaurs have been traditionally held as rather "primitive" animals in regards to terrestrial locomotion, particularly in regards to archosaurs such as crocodilians, lacking the erect gait seen in these, other pseudosuchians, dinosaurs and pterosaurs. However, the ''Apatopus'' ichnofossil shows that the animals did in fact have an erect gait like their archosaur relatives.<ref>Padian, K., Li, C., & Pchelnikova, J. 2010. The trackmaker of (Late Triassic, North America): implications for the evolution of archosaur stance and gait. Palaeontology 53, 175–189.</ref><ref>Klein, H. & Lucas, S. G. 2013. The Late Triassic tetrapod ichnotaxon Apatopus lineatus (Bock, 1952) and its distribution. Bulletin of the New Mexico Museum of Natural History 61, 313–324.</ref>
Most phytosaurs are thought to be aquatic animals, and indeed most do show adaptations for such a lifestyle; swim tracks attributed to phytosaurs, for example, are known.<ref name="Stocker, M. R. 2013">Stocker, M. R. & Butler, R. J. 2013. [https://www.academia.edu/2491440/Phytosauria Phytosauria]. Geological Society, London, Special Publications 379, 91–117. Link is broken.</ref> However, at least ''Nicrosaurus'' seems to have evolved towards a secondarily terrestrial lifestyle, developing longer limb bones, straighter femora and a deeper pelvis, and indeed occurs in terrestrial or marginal lacustrine settings. Combined with its deep upper jaw, it probably led a similar lifestyle to terrestrial predatory crocodylomorphs like sebecians.<ref>Kimmig, J. 2013. Possible secondarily terrestrial lifestyle in the European phytosaur Nicrosaurus kapfii (Late Triassic, Norian): a preliminary study. Bulletin of the New Mexico Museum of Natural History and Science 61, 306–312.</ref>
Inversely, some dolichorostral forms like ''Mystriosuchus'' have become further specialised to life in the water, and occurred in marine environments.<ref>{{Cite journal | url=https://academic.oup.com/zoolinnean/article-abstract/187/1/198/5487160 |title= Description and phylogenetic placement of a new marine species of phytosaur (Archosauriformes: Phytosauria) from the Late Triassic of Austria |doi-access=free |doi=10.1093/zoolinnean/zlz014 |journal=Zoological Journal of the Linnean Society|date= 2019 |last1= Butler |first1= Richard J. |last2= Jones |first2= Andrew S. |last3= Buffetaut |first3= Eric |last4= Mandl |first4= Gerhard W. |last5= Scheyer |first5= Torsten M. |last6= Schultz |first6= Ortwin |volume= 187 |pages= 198–228 }}</ref> A skeleton of ''Mystriosuchus planirostris'', found in a marine setting and with evidence of little post-mortem transportation – indicating that it died either at sea or in a freshwater environment nearby – shows that this animal had paddle-like limbs, less adapted for terrestrial locomotion than in most other phytosaurs.<ref name="Gozzi, E. 2003">{{cite journal|last1=Gozzi|first1=E.|last2=Renesto|first2=S.A.|year=2003|title=Complete specimen of ''Mystriosuchus'' (Reptilia, Phytosauria) from the Norian (Late Triassic) of Lombardy (Northern Italy)|journal=Rivista Italiana di Paleontologia e Stratigrafia|volume=109|issue=3|pages=475–498}}</ref> Furthermore, the tail of ''Mystriosuchus'' was laterally compressed and could have been used in propulsion.<ref name=renesto99>{{cite journal|last1=Renesto|first1=S.A.|last2=Lombardo|first2=C.|year=1999|title=Structure of the tail of a phytosaur (Reptilia, Archosauria) from the Norian (Late Triassic) of Lombardy (Northern Italy)|journal=Nota Breve, Rivista Italiana di Paleontologia e Stratigrafia|volume=105|issue=1|pages=135–144}}</ref>
===Endocast studies=== Scans on various phytosaur braincases suggest that these animals generally had long olfactory tracts, weakly demarcated cerebral regions, dorsoventrally short endosseous labyrinths and various sinuses, including large antorbital and dural venous ones; the general bauplan is vaguely similar to that of crocodilians, but differs significantly in the presence of multiple sinuses, smaller cerebral hemispheres and smaller endosseous labyrinths. The similarities are considered to be plesiomorphic in relation to the ancestral archosauriform design, lacking many features seen in avemetatarsalians, though convergence in terms of lifestyle might also play a role.<ref>Lautenschlager, S. & Butler, R.J. Neural and endocranial anatomy of Triassic phytosaurian reptiles and convergence with fossil and modern crocodylians Article in PeerJ 4(7):e2251 · July 2016 {{doi|10.7717/peerj.2251|doi-access=free}}</ref>
===Reproduction=== No phytosaur eggs have been found so far. There are pits associated with footprints in the Chinle Formation, but these "nests" are apparently the result of sandstone weathering.<ref>Anatomy, Phylogeny and Palaeobiology of Early Archosaurs and Their Kin Capa Sterling J. Nesbitt, Julia Brenda Desojo, Randall B. Irmis Geological Society of London, 2013 – 608 páginas</ref> A recent study suggests they might have had parental care.<ref>{{Cite journal|url=https://www.tandfonline.com/doi/full/10.1080/02724634.2019.1726361|doi=10.1080/02724634.2019.1726361|title=Taphonomic signatures of a new Upper Triassic phytosaur (Diapsida, Archosauria) bonebed from India: Aggregation of a juvenile-dominated paleocommunity|year=2019|last1=Datta|first1=Debajit|last2=Mukherjee|first2=Debarati|last3=Ray|first3=Sanghamitra|journal=Journal of Vertebrate Paleontology|volume=39|issue=6|article-number=e1726361|bibcode=2019JVPal..39E6361D |s2cid=219087095|url-access=subscription}}</ref>
==History== When the first phytosaur fossils were found, it was not immediately obvious what kind of animal/species they were. The first phytosaur species known to science was ambiguously referred to by G. Jaeger in 1828 as "the genus of ''Phytosaurus'', which I call ''Cylindricodon.''" The collective group name, meaning "plant lizard with cylindrical teeth," was coined due to Jaeger's mistaken belief that petrified mud fillings in the jaw were herbivore teeth.
Authorship of the genus name ''Phytosaurus'' is credited to Wagler, 1830, who was the first person to unambiguously use the binomen ''Phytosaurus cylindricodon'' when describing Jaeger's findings. This commonly used genus name ''Phytosaurus'' Wagler, 1830, is invalid according to ICZN code as a junior homonym of the collective-group name ''Phytosaurus'' Jaeger, 1928 (per Article 39).<ref name=":0">{{Cite journal |last=Kischlat |first=Edio-Ernst |date=2022-04-12 |title=Phytosaurian Nomenclature: Parasuchia, Phytosauria or Belodontia? |url=https://sbpbrasil.org/publications/index.php/rbp/article/view/254 |journal=Revista Brasileira de Paleontologia |volume=25 |issue=1 |pages=38–50 |doi=10.4072/rbp.2022.1.03|doi-access=free }}</ref>
The name of the group – Phytosauria – was coined on the basis of ''Phytosaurus'' named by Jæger (1828). However, while the name ''Phytosaurus'' is available as a collective-group name, it was originally not introduced simultaneously as a family-group name and genus-group name, with both categories being mutually exclusive, so it does not conform to the ICZN (ICZN) article 1.2.2. While the nominal genus ''Phytosaurus'' as named by Wagler (1830) is available, it represents a junior homonym. Its usage as a family-group name also does not conform to various ICZN articles (11.7.1.1, & 11.7.2, & 29, & 63, & 64); it was not named in the nominative plural, so the authorship of Phytosauria purportedly should not be attributed Meyer (1861) but to Baur (1894), and not subsequently used as valid in the family-group taxon. The 2022 study suggested that while the class-group names Parasuchia and Belodontia and the family-group name Belodontidae could be used instead of Phytosauria and Phytosauridae, the best solution to resolve this taxonomic issue would be to designate a neotype for ''Belodon plieningeri'' due to the taxonomic restrictions to the name ''Belodon''.<ref name=":0" />
The second species to be described was ''Belodon plieningeri'' by von Meyer in von Meyer and Plieninger 1844. The altogether more appropriate name ''Parasuchia'' ("alongside the crocodiles", as they resembled crocodiles to a great degree) was coined by Thomas Huxley in 1875 along with his discovery and naming of the Indian species ''Parasuchus hislopi'' (Chatterjee, 1978), on the basis of a partial snout. The specimen is usually considered non-diagnostic, and the name ''Parasuchus'' is replaced by ''Paleorhinus''.
The name ''phytosaur'' remains the standard vernacular for these animals, despite its invalid status by ICZN code and the fact that these animals have been clearly shown to be carnivorous. More valid names for the clade include Parasuchia (Huxley, 1875) and Belodontia (Brauns, 1890), which are preferred for formal classification.<ref name=":0" />
==Evolutionary history== thumb|Phytosaur skull Phytosaurs first appeared during the Carnian or Ladinian age, evolving from an unknown crurotarsan ancestor. There are no clear intermediate forms, as even the earliest known phytosaurs are highly specialized aquatic animals, unlike most contemporary archosauriforms that were terrestrial. However, a recent study has suggested that ''Diandongosuchus'' is a basal phytosaur. If this is the case, this taxon offers more of a bridge between phytosaurs and earlier Archosauriformes.<ref>Michelle R. Stoker; Sterling J. Nesbitt; Li-Jun Zhao; Xiao-Chun Wu; Chun Li (2016). "Mosaic evolution in Phytosauria: the origin of long-snouted morphologies based on a complete skeleton of a phytosaur from the Middle Triassic of China". Society of Vertebrate Paleontology 76th Annual Meeting Program & Abstracts: 232.</ref>
The earliest phytosaurs are traditionally classified in the genus ''Paleorhinus'', now thought to be polyphyletic. ''Parasuchus'' and related basal species were widely distributed, meaning that phytosaurs dispersed across Pangea early on and there were probably few geographical barriers for their distribution; only in the southernmost regions are they rare, possibly due to increased aridity.<ref>"Relationships of the Indian phytosaur Parasuchus hislopi Lydekker, 1885", Article · July 2015 DOI: 10.1002/spp2.1022</ref>
A somewhat more advanced and larger form, ''Angistorhinus'' appears at the same time or soon after. Later in the Carnian, both these animals were replaced by more specialised forms like ''Rutiodon'', ''Leptosuchus'', and the huge ''Smilosuchus'' (Lucas 1998). The Carnian-Norian extinction meant that these animals died off, and the Early Norian sees new genera like ''Nicrosaurus'' and ''Pseudopalatus'', both of which belong to the most derived clade of phytosaurs, the Pseudopalatinae. Later in the middle Norian the advanced and specialised fish-eater ''Mystriosuchus'' appears. Fossil remains of this widespread animal is known from Germany, northern Italy, and Thailand. Finally the large ''Redondasaurus'' in southwest North America and the long-snouted (altirostral) ''Angistorhinopsis ruetimeyeri'' in Europe continued the group into the Rhaetian. Phytosaur footprints (the ichnotaxon ''Apatopus'') are also known from the latest Rhaetian of the East Coast of USA (the Newark Supergroup) (Olsen ''et al.'' 2002). This indicates that phytosaurs continued as successful animals until the very end of the Triassic, when, along with many other large crurotarsan reptiles, they were killed off by the end Triassic extinction event, about 200 Ma ago.
There have been reports of phytosaur remains found in lowermost Jurassic rocks. Several teeth from Early Jurassic deposits in France have been identified as phytosaur teeth, but other studies argue they have either been misidentified or were reworked from Late Triassic into Early Jurassic deposits. In 1951, a partial upper jaw was discovered in the Early Jurassic Lower Lufeng Series in China and described as a new genus of phytosaur, ''Pachysuchus'', but a study in 2012 reinterpreted the fossil as a sauropodomorph dinosaur.<ref name=BX12>{{cite journal |author=Paul M. Barrett and Xu Xing |year=2012 |title=The enigmatic reptile ''Pachysuchus imperfectus'' Young, 1951 from the Lower Lufeng Formation (Lower Jurassic) of Yunnan, China |journal=Vertebrata PalAsiatica |volume=50 |issue=2 |pages=151–159 |url=http://www.ivpp.cas.cn/cbw/gjzdwxb/xbwzxz/201204/P020120423369779799608.pdf}}</ref>
A fragment of a lower jaw from a longirostrine archosaur has been described from early Hettangian strata in the town of Watchet in Somerset, England. While teleosaurid thalattosuchians had similar longirostrine jaws to phytosaurs and were common in the Jurassic, they do not appear in the earliest Jurassic rocks. The mandible is more similar to those of known phytosaurs than to thalattosuchians, and likely belongs to a phytosaur closely related to the genus ''Mystriosuchus''. The presence of phytosaurs in the earliest Jurassic may have prevented thalattosuchians from occupying similar ecological niches at that time.<ref name=MK10 /> However, more recent work suggests that the jaw fragment came from a pre-Hettangian rock unit, and is therefore Late Triassic in age.<ref name=BX12/> Also, if the age of the Magnesian Conglomerate does extend into the Early Jurassic (Hettangian), then it is possible that ''Rileyasuchus'' survived into the Early Jurassic.<ref name=APH94>Hunt, A.P. (1994). Unpublished doctoral dissertation, [http://dml.cmnh.org/2000Feb/msg00297.html discussed here] {{Webarchive|url=https://web.archive.org/web/20061017170227/http://dml.cmnh.org/2000Feb/msg00297.html |date=17 October 2006 }}</ref>
In August 2025, Indian media reported a ~1.5–2 m-long fossil from Megha village near Jaisalmer (Lathi Formation, Rajasthan) that was preliminarily identified as a phytosaur from Jurassic-age strata, with an egg-like fossil noted alongside the skeleton.<ref>{{Cite web |last=Bhatia |first=Vimal |date=2025-08-26 |title=Rare jurassic-era fossils, including skeleton and egg, discovered in Jaisalmer |url=https://www.indiatoday.in/science/story/rare-jurassic-era-fossils-including-skeleton-and-egg-discovered-in-jaisalmer-2776683-2025-08-26 |access-date=2025-08-26 |website=India Today |language=en}}</ref><ref name=":1">{{Cite news |date=2025-08-25 |title=After 'Flying Dinosaur', India's first 20-crore-year-old Phytosaur fossil unearthed in Jaisalmer |url=https://economictimes.indiatimes.com/news/new-updates/after-flying-dinosaur-indias-first-20-crore-year-old-phytosaur-fossil-unearthed-in-jaisalmer/articleshow/123504922.cms |access-date=2025-08-26 |work=The Economic Times |issn=0013-0389}}</ref> If confirmed, this would represent well-preserved phytosaur material from Jurassic rocks in India; researchers emphasized the identification is preliminary and subject to further study.<ref name=":1" /><ref>{{Cite web |date=2025-08-22 |title=Suspected dinosaur-era fossils found during pond excavation in Jaisalmer, GSI probe ordered |url=https://indianexpress.com/article/india/suspected-dinosaur-era-fossils-found-during-pond-excavation-in-jaisalmer-gsi-probe-ordered-10203753/ |access-date=2025-08-26 |website=The Indian Express |language=en}}</ref>
==Classification==
===Genera=== {| class="wikitable sortable" align="center" width="100%" |- ! Genus ! Status ! Age ! Location ! Unit ! class="unsortable" | Notes ! class="unsortable" | Images |- | ''Angistorhinopsis'' | Junior synonym | | | | Junior synonym of ''Nicrosaurus'' | |- | ''Angistorhinus'' | Valid | Late Carnian | {{flag|Morocco}}<br/> {{flag|US}} | Argana Formation<br /> Dockum Group<br /> Popo Agie Formation | | 150px |- | ''Arganarhinus'' | Valid | Middle Carnian | {{flag|Morocco}} | Argana Formation | | |- | ''Arribasuchus'' | Junior synonym | | | | Junior synonym of ''Machaeroprosopus'' | |- | ''Belodon'' | ''Nomen dubium'' | Middle Norian | {{flag|Germany}}<br /> {{flag|US}} | Stubensandstein<br /> Chinle Formation | Many remains have since been attributed to other animals or given their own genera | 150px |- | ''Brachysuchus'' | Valid | Carnian | {{flag|US}} | "Pre-Tecovas Horizon" (Dockum Group) | | |- | ''Calamosuchus'' | Valid | Carnian | {{flag|Germany}} | Stuttgart Formation | A genus name for "''Zanclodon''" ''arenaceus''; a possible early-diverging phytosaur,<ref name="S&S25">{{Cite journal |last1=Sues |first1=Hans-Dieter |last2=Schoch |first2=Rainer R. |date=2025-12-04 |title=Synopsis of the Triassic reptiles from Germany |journal=Fossil Record |language=en |volume=28 |issue=2 |pages=411–483 |doi=10.3897/fr.28.164405 |doi-access=free |issn=2193-0074}}</ref> previously argued to belong outside this clade<ref name="A.H.2001">{{Cite journal |last1=Hungerbühler |first1=Axel |date=August 2001 |title=The status and phylogenetic relationships of "''Zanclodon''" ''arenaceus'': the earliest known phytosaur? |journal=Paläontologische Zeitschrift |language=en |volume=75 |issue=1 |pages=97–112 |doi=10.1007/BF03022600 |issn=0031-0220}}</ref> | 150px |- | ''Centemodon'' | ''Nomen dubium'' | Norian | {{flag|US}} | Cumnock Formation | Named from several teeth in 1856 | |- | ''Coburgosuchus'' | Valid | Norian | {{Flag|Germany}} | | | |- |''Colossosuchus'' |Valid |Carnian-Norian |{{flag|India}} |Tiki Formation | | |- | ?''Diandongosuchus'' | Valid | Ladinian | {{Flag|China}} | Falang Formation | Possibly the basalmost phytosaur | 150px |- | ''Ebrachosuchus'' | Valid | Late Carnian | {{flag|Germany}} | Hassberge Formation | | |- | ''Francosuchus'' | ''Nomen dubium'' | Late Carnian | {{flag|Germany}} | Hassberge Formation | | |- | ''Leptosuchus'' | Valid | Carnian | {{flag|US}} | Tecovas Formation and unknown formation (Dockum Group) | | |- | ''Machaeroprosopus'' | Valid | Carnian-Norian | {{flag|US}} | Chinle Formation<br /> Dockum Group | | 150px |- | ''Mesorhinosuchus'' | ? Valid | Triassic, ? early Olenekian | {{flag|Germany}} | ? Middle Buntsandstein | | |- | ''Mystriosuchus'' | Valid | Middle Norian | {{flag|Germany}} | Stubensandstein | | |- | ''Nicrosaurus'' | Valid | Late Norian – Rhaetian | {{flag|France}}<br/> {{flag|Germany}} | Arnstadt Formation<br/> Upper Keuper | | 150px |- | "Paleorhinus" | Junior synonym | Late Carnian | {{flag|Germany}}<br /> {{flag|Poland}}<br /> {{flag|US}}<br /> {{flag|Lithuania}} | Hassberge Formation<br /> Middle Keuper<br /> Cooper Canyon Formation<br /> Popo Agie Formation<br /> Tecovas Formation<br /> Nemunas Formation | Polyphyletic. | |- | ''Parasuchus'' | Valid | Late Carnian – Early Norian | {{flag|India}} | Lower Maleri Formation<br /> Tiki Formation | | 150px |- | ''Pravusuchus'' | Valid | Norian | {{flag|US}} | Chinle Formation | | |- | ''Promystriosuchus'' | Valid | | | | | |- | ''Protome'' | Valid | Norian | {{flag|US}} | Chinle Formation | | 150px |- | ''Pseudopalatus'' | Junior synonym | | | | Junior synonym of ''Machaeroprosopus'' | |- | ''Redondasaurus'' | Valid | Norian – Rhaetian | {{flag|US}} | Redonda Formation<br /> Travesser Formation | | 150px |- | ''Rutiodon'' | Valid | Carnian | {{flag|US}} | Newark Supergroup | | 150px |- | ''Smilosuchus'' | Valid | Carnian | {{flag|US}} | Chinle Formation | | 150px |- | ''Volcanosuchus'' | Valid | Carnian | {{flag|India}} | Tiki Formation | | |- | ''Wannia'' | Valid | Carnian-Norian | {{flag|US}} | Camp Springs Formation | | |}
===Phylogeny=== Phytosaurs are generally regarded as the most basal group of Crurotarsi, a clade of archosaurs that includes crocodilians and their extinct relatives.<ref name=BMJ99>{{cite journal |last=Benton |first=M.J. |year=1999 |title=''Scleromochlus taylori'' and the origin of dinosaurs and pterosaurs |journal=Philosophical Transactions of the Royal Society B: Biological Sciences |volume=354 |issue=1388 |pages=1423–1446 |doi=10.1098/rstb.1999.0489 |url=http://doc.rero.ch/lm.php?url=1000,43,39,20091210002555-ZZ/PAL_E1968.pdf|pmc=1692658 }}</ref><ref name=NSJ07>{{cite journal |last=Nesbitt |first=S.J. |year=2007 |title=The anatomy of ''Effigia okeeffeae'' (Archosauria, Suchia), theropod-like convergence, and the distribution of related taxa |journal=Bulletin of the American Museum of Natural History |volume=302 |pages=1–84 |doi=10.1206/0003-0090(2007)302[1:TAOEOA]2.0.CO;2 |url=http://digitallibrary.amnh.org/dspace/bitstream/2246/5840/1/B302.pdf|hdl=2246/5840 |s2cid=55677195 }}</ref><ref name=Betal10>{{cite journal |last=Brusatte |first=S.L. |author2=Benton, M.J. |author3=Desojo, J.B. |author4= Langer, M.C. |year=2010 |title=The higher-level phylogeny of Archosauria (Tetrapoda: Diapsida) |journal=Journal of Systematic Palaeontology |volume=8 |issue=1 |pages=3–47 |doi=10.1080/14772010903537732 |bibcode=2010JSPal...8....3B |s2cid=59148006 |url=https://www.pure.ed.ac.uk/ws/files/8232155/PDF_Brusatteetal2010ArchosaurPhylogeny.pdf |hdl=20.500.11820/24322ff3-e80e-45f2-8d53-d35fd104195c |hdl-access=free }}</ref> Phytosaurs are often excluded from a clade called Suchia, which usually encompasses all other crurotarsans, including aetosaurs, rauisuchians, and crocodylomorphs.<ref name=Betal10/> Some studies have found polytomies between phytosaurs and other groups, like Ornithosuchidae and Suchia. In these cases, it is unclear whether phytosaurs are the most basal crurotarsans.<ref name=GW96>{{cite journal |last=Gower |first=D.J. |author2=Wilkinson, M. |year=1996 |title=Is there any consensus on basal archosaur phylogeny? |journal=Proceedings of the Royal Society B: Biological Sciences |volume=263 |issue=1375 |pages=1399–1406|doi=10.1098/rspb.1996.0205 |s2cid=86610229 }}</ref> In one of the earliest studies of crurotarsan phylogeny, Sereno and Arcucci (1990) found Crurotarsi to be a monophyletic grouping consisting of phytosaurs, ornithosuchids, and the more derived suchians, but produced a trichotomy between the three groups in their tree.<ref name=SA90>{{cite journal |last=Sereno |first=P.C. |author2=Arcucci, A.B. |year=1990 |title=The monophyly of crurotarsal archosaurs and the origin of bird and crocodile ankle joints |journal=Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen |volume=180 |pages=21–52|doi=10.1127/njgpa/180/1990/21 |s2cid=256805773 }}</ref> In resolving this trichotomy, Parrish (1993) placed ornithosuchids, not phytosaurs, as the most basal crurotarsans. However, most other studies, such as Sereno (1991) and Benton ''et al.'' (2010), recover phytosaurs in a basalmost position among crurotarsans.<ref name=SPC91>{{cite journal |last=Sereno |first=P.C. |year=1991 |title=Basal archosaurs: phylogenetic relationships and functional implications |journal=Journal of Vertebrate Paleontology |volume=11 |issue=4, Supplement |pages=1–53 |doi=10.1080/02724634.1991.10011426|bibcode=1991JVPal..11S...1S }}</ref> Below is a cladogram modified from Benton ''et al.'' (2010) showing the widely accepted phylogenetic relationships of phytosaurs:<ref name=Betal10/>
{{clade| style=font-size:100%;line-height:85% |label1=Archosauria |1={{clade |1=Avemetatarsalia 40 px |label2=Crurotarsi |2={{clade |1='''Phytosauria''' 100x80px |label2=Suchia |2={{clade |1={{clade |1=Aetosauria 100x80px |2=Crocodylomorpha 100x80px }} |2={{clade |1=Ornithosuchidae 100x80px |2=Rauisuchia 100x80px }} }} }} }} }}
A phylogenetic analysis of early archosaurs by paleontologist Sterling Nesbitt (2011) found strong support for a sister taxon relationship between phytosaurs and Archosauria.<ref name="NSJ11"/> If this is the case, phytosaurs would be placed outside Pseudosuchia in a more basal position among archosauriforms. Phytosaurs would be considered closely related to the ancestors of both crocodilians and dinosaurs. Furthermore, the definition of the clade Crurotarsi would change, as it is often defined by the inclusion of phytosaurs. Thus, Crurotarsi would include phytosaurs and all other archosaurs —including dinosaurs— under this phylogeny.<ref name=Chin11>{{cite web |url=https://chinleana.blogspot.com/2011/04/dinosaurs-are-crurotarsans.html |title=Dinosaurs Are Crurotarsans |first=Bill |last=Parker |date=27 April 2011 |work=Chinleana |publisher=Blogger |access-date=27 April 2011}}</ref> Below is a cladogram showing the placement of phytosaurs from Nesbitt (2011):<ref name=NSJ11/>
{{clade| style=font-size:100%;line-height:85% |label1=Archosauriformes |1={{clade |1=''Proterosuchus'' 100x80px |2={{clade |1=''Erythrosuchus'' 100x80px |2={{clade |1=''Vancleavea'' 100x80px |2={{clade |label1=Proterochampsia |1={{clade |1=''Tropidosuchus'' <div style="{{MirrorH}}">100x80px</div> |2=''Chanaresuchus'' 100x80px}} |2={{clade |1=''Euparkeria'' <div style="{{MirrorH}}">100x80px</div> |label2=Crurotarsi |2={{clade |label1='''Phytosauria''' |1={{clade |1=''Parasuchus'' |2={{clade |1=''Leptosuchus'' <div style="{{MirrorH}}">100x80px</div> |2=''Pseudopalatus''}} }} |label2=Archosauria |2={{clade |1=Pseudosuchia 100x80px |2=Avemetatarsalia 40 px }} }} }} }} }} }} }} }}
The phylogenetic analysis of Stocker (2010) placed ''Paleorhinus'' outside Phytosauridae as a basal phytosaur. Under this phylogeny, Phytosauridae and Phytosauria are not synonymous. Stocker also erected the clade Leptosuchomorpha for derived phytosaurs, including ''Leptosuchus'' and ''Smilosuchus''.<ref name="Stocker2010">{{cite journal|author=Michelle R. Stocker |year=2010 |title=A new taxon of phytosaur (Archosauria: Pseudosuchia) from the Late Triassic (Norian) Sonsela Member (Chinle Formation) in Arizona, and a critical reevaluation of ''Leptosuchus'' Case, 1922 |journal=Palaeontology |volume=53 |issue=5 |pages=997–1022 |doi=10.1111/j.1475-4983.2010.00983.x |bibcode=2010Palgy..53..997S |s2cid=83536253 |doi-access=free }}</ref>
Ezcurra (2016) updated Nesbitt's analysis and found that Phytosauria was once again a group of basal pseudosuchian archosaurs. His study analyzed the ten phylogenetic traits which Nesbitt claimed were lacking in phytosaurs but not archosaurs, thus excluding phytosaurs from Pseudosuchia. Four of the traits (well-developed palatal processes of the maxilla which meet at the midline, an elongated cochlear recess, a tuber on the lateral side of the ulna, and a particular orientation of the calcaneal tuber) were confirmed to support Nesbitt's placement of Phytosauria. However, one of the ten traits was found in ''Euparkeria'' (an abducens nerve exit foramen only present in the prootic) and another was found in proterochampsians (a swollen biceps tubercule), so their lack in phytosaurs may be reversals rather than basal traits. Another one of the traits (an antorbital fossa contacting the horizontal process of the maxilla) was found in the basal phytosaur ''Parasuchus.'' One trait (short metacarpals compared to metatarsals) was difficult to analyze in any crurotarsan, and another (a medial tuber on the femur) was found in both proterochampsids and ''Parasuchus''. One trait (a divided tibial facet of the astragalus) was also lacking in ''Marasuchus'' and ''Nundasuchus'', and therefore had a variable existence in Archosauria. This reanalysis, along with the observance of many traits linking Phytosauria with pseudosuchians, concluded that it was more likely that phytosaurs were pseudosuchians than non-archosaur archosauriforms. The following cladogram is a simplified version the fourth strict reduced consensus tree of Ezcurra's third phylogenetic analyses within his study. This cladogram only shows taxa from the group Eucrocopoda.<ref>{{Cite journal|last=Ezcurra|first=Martín D.|date=2016-04-28|title=The phylogenetic relationships of basal archosauromorphs, with an emphasis on the systematics of proterosuchian archosauriforms|journal=PeerJ|language=en|volume=4|article-number=e1778|doi=10.7717/peerj.1778|pmid=27162705|issn=2167-8359|pmc=4860341 |doi-access=free }}</ref>
{{clade| style=font-size:100%;line-height:85% |label1=Eucrocopoda |1={{clade |1=''Dorosuchus'' |2={{clade |1=''Euparkeria'' <div style="{{MirrorH}}">100x80px</div> |2={{clade |1=''Dongusuchus'' |2=''Yarasuchus'' <div style="{{MirrorH}}">100x80px</div>}} |3={{clade |label1=Proterochampsia |1={{clade |1=Doswelliidae <div style="{{MirrorH}}">100x80px</div> |2=Proterochampsidae <div style="{{MirrorH}}">100x80px</div> }} |label2=Archosauria |2={{clade |1=Ornithodira 40 px |label2=Pseudosuchia |2={{clade |label1='''Phytosauria''' |1={{clade |1={{clade |1=''Parasuchus hislopi'' |2=''Parasuchus angustifrons''}} |2={{clade |1=''Nicrosaurus kapfii'' |2=''Smilosuchus'' spp. 100x80px}} }} |2={{clade |1=''Nundasuchus'' <div style="{{MirrorH}}">100x80px</div> |2={{clade |1=Ornithosuchidae 100x80px |2=Suchia 100x80px }} }} }} }} }} }} }} }}
==Paleoecology== In the Late Triassic coprolite which could belong to a phytosaur, eggs of nematodes and probably protozoan cysts were found.<ref>{{cite journal|author=Thanit Nonsrirach, Serge Morand, Alexis Ribas, Sita Manitkoon, Komsorn Lauprasert, Julien Claude|date=9 August 2023|title=First discovery of parasite eggs in a vertebrate coprolite of the Late Triassic in Thailand|journal=PLOS ONE|volume=18 |issue=8 |article-number=e0287891 |doi=10.1371/journal.pone.0287891|pmid=37556448|pmc=10411797 |bibcode=2023PLoSO..1887891N |doi-access=free }}</ref>
==Footnotes== {{Reflist|2|refs= <ref name="alberto-tooth-abs-84">"Abstract," Abler (2001). Page 84.</ref> <ref name=MK10>Maisch and Kapitzke (2010).</ref> }}
==Sources== * Abler, W.L. 2001. A kerf-and-drill model of tyrannosaur tooth serrations. p. 84–89. In: ''Mesozoic Vertebrate Life''. Ed.s Tanke, D. H., Carpenter, K., Skrepnick, M. W. Indiana University Press. * Carroll, R.L. (1988). ''Vertebrate Paleontology and Evolution'', WH Freeman & Co. * Chatterjee, S. (1978). A primitive parasuchid (phytosaur) reptile from the Upper Triassic Maleri Formation of India, ''Palaeontology'' '''21''': 83–127 * Hungerbühler, A. (2002). The Late Triassic phytosaur ''Mystriosuchus'' Westphali, with a revision of the genus. ''Palaeontology'' '''45''' (2): 377–418 * Jaeger, G.F. 1828. Über die fossilen Reptilien, welche in Würtemberg aufgefunden worden sind. Metzler, Stuttgart. * Kimmig, J. & Arp, G. (2010) Phytosaur remains from the Norian Arnstadt Formation (Leine Valley, Germany), with reference to European phytosaur habitats. ''Palaeodiversity'' '''3''': 215–224 * Lucas, S.G. (1998). Global Triassic tetrapod biostratigraphy and biochronology. ''Paleogeog. Palaeoclimatol., Palaeoecol.'' '''143''': 347–384. * {{cite journal |last=Maisch |first=M.W. |author2=Kapitzke, M. |year=2010 |title=A presumably marine phytosaur (Reptilia: Archosauria) from the pre-planorbis beds (Hettangian) of England |journal=Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen |volume=257 |issue=3 |pages=373–379 |doi=10.1127/0077-7749/2010/0076}} * Olsen, P.E., Kent, D.V., H.-D.Sues, Koeberl, C., Huber, H., Montanari, E.C.Rainforth, A., Fowell, S.J., Szajna, M.J., and Hartline, B.W., (2002). Ascent of dinosaurs linked to an iridium anomaly at the Triassic-Jurassic boundary. ''Science'' '''296''': 1305–1307. * {{cite journal|author=Stocker, Michelle R. |year=2010 |title=A new taxon of phytosaur (Archosauria: Pseudosuchia) from the Late Triassic (Norian) Sonsela Member (Chinle Formation) in Arizona, and a critical reevaluation of Leptosuchus, Case, 1922 |journal=Palaeontology |volume=53 |issue=5 |pages=997–1022 |doi=10.1111/j.1475-4983.2010.00983.x|bibcode=2010Palgy..53..997S |s2cid=83536253 |doi-access=free }} * Ballew, K.L. (1989). A phylogenetic analysis of Phytosauria from the Late Triassic of the Western United States. ''Dawn of the age of dinosaurs in the American Southwest'': pp. 309–339. * Gregory, J.T. (1962). Genera of phytosaurs. ''American Journal of Science'', '''260''': 652–690. * Long, R.A. & Murry, P.A. (1995). Late Triassic (Carnian and Norian) tetrapods from the southwestern United States. ''New Mexico Museum of Natural History and Science Bulletin'', '''4''': 1–254.
== External links == * [https://web.archive.org/web/20050403210835/http://www.dinosauria.com/dml/names/phytoi.htm Translation and Pronunciation Guide] * [https://web.archive.org/web/20050306012858/http://www.faculty.de.gcsu.edu/~bwall1/Publications/Phytosaur.htm A Preliminary Biomechanical Analysis of Phytosaur Life Habits] * [https://web.archive.org/web/20050409174048/http://www.palaeos.com/vertebrates/Units/270Archosauromorpha/270.530.html Phytosauria – Palaeos] * [https://web.archive.org/web/20050309091939/http://www.fmnh.helsinki.fi/users/haaramo/Metazoa/Deuterostoma/Chordata/Archosauria/pseudosuchia/Phytosauria.htm Mikko's Phylogeny] – cladistic tree * [http://rainbow.ldeo.columbia.edu/courses/v1001/chinlenewark10.html Great Triassic Assemblages Pt 1 – The Chinle and Newark] – some material on phytosaurs {{Commons category|position=right||Phytosauria}} {{clear}}
{{Phytosauria}} {{Taxonbar|from=Q131343}}
Category:Phytosauria Category:Crurotarsans Category:Late Triassic reptiles Category:Carnian first appearances Category:Rhaetian extinctions