Gracilisuchidae

{{Short description|Extinct family of reptiles}} {{Automatic taxobox | name = Gracilisuchids | fossil_range = [[Anisian]]-[[Carnian]], {{fossil range|247.2|234|latest=225.4}} <small>[[Norian]] presence if ''[[Maehary]]'' is a member</small> | taxon = Gracilisuchidae | image = {{Multiple image |perrow=2/2/2 |total_width=275 |image1=Gracilisuchus.tif |image2=Parvosuchus skull.png |border=infobox |footer=Skulls of ''[[Gracilisuchus]]'' (left) and ''[[Parvosuchus]]'' (right) }} | authority = Butler et al. [[2014 in paleontology|2014]] | subdivision_ranks = [[Genus|Genera]] | subdivision = * {{extinct}}''[[Gracilisuchus]]'' * {{extinct}}''[[Maehary]]''? * {{extinct}}''[[Parvosuchus]]'' * {{extinct}}''[[Taihangosuchus]]'' * {{extinct}}''[[Telkaralura]]'' * {{extinct}}''[[Turfanosuchus]]'' * {{extinct}}''[[Yonghesuchus]]'' }}

'''Gracilisuchidae''' is an [[extinct]] [[Family (taxonomy)|family]] of [[suchia]]n [[archosaur]]s known from the early [[Middle Triassic]] to the early [[Late Triassic]] ([[Anisian]] – early [[Carnian]]) of China, Argentina, and Brazil.<ref name=Gracilisuchidae>{{Cite journal | doi = 10.1186/1471-2148-14-128| pmid = 24916124| title = New clade of enigmatic early archosaurs yields insights into early pseudosuchian phylogeny and the biogeography of the archosaur radiation| journal = BMC Evolutionary Biology| volume = 14| issue = 1| page = 128| year = 2014| last1 = Butler | first1 = R. J. | last2 = Sullivan | first2 = C. | last3 = Ezcurra | first3 = M. N. D. | last4 = Liu | first4 = J. | last5 = Lecuona | first5 = A. | last6 = Sookias | first6 = R. B. | pmc=4061117| doi-access = free| bibcode = 2014BMCEE..14..128B}}</ref><ref name="Parvosuchus">{{Cite journal |last1=Müller |first1=Rodrigo T. |date=2024-06-20 |title=A new small-sized predatory pseudosuchian archosaur from the Middle-Late Triassic of Southern Brazil |journal=[[Scientific Reports]] |language=en |volume=14 |issue=1 |page=12706 |doi=10.1038/s41598-024-63313-3 |issn=2045-2322|doi-access=free |pmc=11189902 }}</ref>

==Distribution== The oldest known gracilisuchids are ''[[Turfanosuchus dabanensis]]'' and ''[[Taihangosuchus wuxiangensis]]'' from the [[Anisian]] stage of [[Xinjiang]] and [[Shanxi Province]], China, respectively.<ref name="Taihangosuchus">{{Cite journal|last1=Wu |first1=X.-C. |last2=Kang |first2=Z. |last3=Shi |first3=J. |last4=You |first4=H.-L. |last5=Dong |first5=L. |title=''Taihangosuchus wuxiangensis'', a new gracilisuchid (Archosauria: Pseudosuchia) from the Middle Triassic of Shanxi Province, China |year=2025 |journal=Historical Biology: An International Journal of Paleobiology |doi=10.1080/08912963.2025.2537848 }}</ref> Two gracilisuchids are known from the [[Ladinian]] or early [[Carnian]] stage, ''[[Gracilisuchus stipanicicorum]]'' and ''[[Yonghesuchus sangbiensis]]'', from [[La Rioja Province, Argentina|La Rioja Province]] of Argentina, and [[Shanxi]], respectively. These species were considered enigmatic prior to the recognition of the family in 2014, suggesting a rapid [[phylogenetic]] [[Biodiversity|diversification]] of archosaurs by the [[Middle Triassic]]. This radiation is a part of the broader recovery of terrestrial ecosystems after the [[Permian–Triassic extinction event]]. Gracilisuchids are known from approximately similar northern and southern mid-palaeolatitudes, demonstrating a wide distribution of early archosaurs over much or all of [[Pangaea]] by the early Middle Triassic.<ref name=Gracilisuchidae/> ''[[Parvosuchus]]'', from Brazil's [[Santa Maria Formation]] (Ladinian–Carnian boundary), represents the first unequivocal gracilisuchid from the country. ''[[Maehary]]'', known from the [[Caturrita Formation]] ([[Norian]] stage) of Brazil, is likely a gracilisuchid, although it was originally described as an early-diverging [[pterosauromorph]].<ref name="Maehary">{{cite journal|last1=Kellner|first1=A.W.A.|last2=Holgado|first2=B.|last3=Grillo|first3=O.|last4=Pretto|first4=F.A.|last5=Kerber|first5=L.|last6=Pinheiro|first6=F.L.|last7=Soares|first7=M.B.|last8=Schultz|first8=C.L.|last9=Lopes|first9=R.T.|last10=Araújo|first10=A.|last11=Müller|first11=R.T.|year=2022|title=Reassessment of ''Faxinalipterus minimus'', a purported Triassic pterosaur from southern Brazil with the description of a new taxon|journal=PeerJ|volume=10|article-number=e13276|doi=10.7717/peerj.13276|pmid=35529502 |pmc=9074864 |doi-access=free}}</ref><ref name="Parvosuchus"/>

==History== The family Gracilisuchidae first appeared in a [[biological classification|classification]] scheme for all fossil [[vertebrate]]s, published by [[Robert L. Carroll]] in 1988. As no description or definition were provided by Carroll for the erection of the name, it is unavailable under Article 13.1.1 of the [[International Code of Zoological Nomenclature]]. Richard J. Butler, Corwin Sullivan, Martín D. Ezcurra, Jun Liu, Agustina Lecuona and Roland B. Sookias described and officially named the family in [[2014 in paleontology|2014]], to include several early [[archosaur]]s, previously considered enigmatic. They phylogenetically defined the family as the most inclusive clade containing ''[[Gracilisuchus stipanicicorum]]'', but not ''[[Ornithosuchus|Ornithosuchus woordwardi]]'', ''[[Aetosaurus ferratus]]'', ''[[Poposaurus gracilis]]'', ''[[Postosuchus kirkpatricki]]'', ''[[Rutiodon carolinensis]]'', ''[[Erpetosuchus granti]]'', ''[[Revueltosaurus callenderi]]'', ''[[Crocodylus niloticus]]'' (the Nile Crocodile), or ''[[Passer domesticus]]'' (the house sparrow).<ref name=Gracilisuchidae>{{Cite journal | doi = 10.1186/1471-2148-14-128| pmid = 24916124| title = New clade of enigmatic early archosaurs yields insights into early pseudosuchian phylogeny and the biogeography of the archosaur radiation| journal = BMC Evolutionary Biology| volume = 14| issue = 1| page = 128| year = 2014| last1 = Butler | first1 = R. J. | last2 = Sullivan | first2 = C. | last3 = Ezcurra | first3 = M. N. D. | last4 = Liu | first4 = J. | last5 = Lecuona | first5 = A. | last6 = Sookias | first6 = R. B. | pmc=4061117| doi-access = free| bibcode = 2014BMCEE..14..128B}}</ref> Apart from ''[[Gracilisuchus stipanicicorum]]'', Carroll assigned to Gracilisuchidae the Middle Triassic ''[[Lewisuchus admixtus]]'', which is now considered a [[silesaurid]] [[dinosauriform]]. ''[[Turfanosuchus dabanensis]]'' and ''[[Yonghesuchus sangbiensis]]'' were considered [[Basal (phylogenetics)|basal]] or [[Crown group|stem]] archosaurs prior to their inclusion in the family in 2014, depending on phylogenetic hypothesis.<ref name=Gracilisuchidae/>

== Classification == In the [[phylogenetic analyses]] accompanying their description of the gracilisuchid ''Taihangosuchus'', Wu et al. (2025) recovered it diverging after the similarly aged Chinese ''Turfanosuchus'', also dating to the Anisian age,<ref name="Gracilisuchidae"/> but before the clade formed by the Chinese ''Yonghesuchus'' and Argentinian ''Gracilisuchus''. These results are congruent with the [[chronostratigraphic]] (relating to rock layers over time) occurrences of these genera, with older genera diverging first, and younger (more recent) genera diverging later. This may imply that gracilisuchids originated in the landmass [[Laurasia]], diversifying in Asia before spreading elsewhere ([[Gondwana]]). While not included in the description of ''Taihangosuchus'', the description of the Brazilian gracilisuchid ''Parvosuchus'' by Müller (2024) recovered a similar topology, with ''Parvosuchus'' in a derived position close to ''Gracilisuchus'', to which it is similar in age.<ref name="Parvosuchus" />

Wu et al. recovered the Gracilisuchidae as the [[sister taxon]] to the [[Erpetosuchidae]], with this clade representing one of the two initial divergences within [[Pseudosuchia]], the other being the more diverse [[Suchia]] (including modern [[crocodilia]]ns). A [[cladogram]] following these results is displayed below:<ref name="Taihangosuchus" />

{{clade |{{clade |1={{clade |label1={{extinct}}[[Erpetosuchidae]] |1={{clade |1={{extinct}}''[[Parringtonia]]'' |2={{extinct}}''[[Erpetosuchus]]'' [[File:Erpetosuchus granti.png|70px]] }} |label3={{extinct}}'''Gracilisuchidae''' |3={{clade |1={{extinct}}''[[Turfanosuchus]]'' [[File:Turfanosuchus dabanensis.png|70px]] |2={{clade |1={{extinct}}''[[Taihangosuchus]]'' |2={{clade |1={{extinct}}''[[Gracilisuchus]]'' <div style="{{MirrorH}}">[[File:Gracilisuchus stipanicicorum.png|70px]]</div> |2={{extinct}}''[[Yonghesuchus]]'' <div style="{{MirrorH}}">[[File:Yonghesuchus sangbiensis.png|70px]]</div> }} }} }} }} |label3=[[Suchia]] |3={{clade |1={{clade |1={{extinct}}[[Aetosauria]] [[File:Desmatosuchus spurensis flipped.jpg|70px]] |2={{extinct}}[[Ornithosuchidae]] <div style="{{MirrorH}}">[[File:Riojasuchus BW.jpg|70px]]</div> }} |3={{clade |1={{extinct}}''[[Ticinosuchus]]'' [[File:Ticinosuchus ferox.png|70px]] |label2=[[Paracrocodylomorpha]] |2={{clade |1={{extinct}}[[Poposauroidea]] [[File:Poposaurus gracilis (1) flipped.jpg|70px]] |2=[[Loricata]] [[File:Deinosuchus illustration Andrey Atuchin.jpg|80px]] }} }} }} }}|label1=[[Pseudosuchia]]}}

== References == {{Portal|Paleontology}} {{Reflist}}

[[Category:Gracilisuchidae| ]] [[Category:Triassic archosaurs]] [[Category:Middle Triassic first appearances]] [[Category:Late Triassic extinctions]] [[Category:Triassic reptiles of Asia]] [[Category:Triassic reptiles of South America]] [[Category:Pseudosuchian families]]