Editing Laquintasaura - Wikipedia
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Like other early members of Ornithischia, it is assumed that ''Laquintasaura'' was a lithe [[bipedal]] animal. The largest femur among the bonebed is {{convert|90|mm|inch}} in length; assuming similar proportions to similar animals like ''[[Hypsilophodon]]'', ''[[Heterodontosaurus]]'', and ''[[Hexinlusaurus]]'', it was estimated the ''Laquintasaura'' individual could grow to around {{convert|1|m|ft}} in length. However, this individual was a subadult, and more fragmentary remains appear to belong to slightly larger animals. The small size and conservative skeletal anatomy of ''Laquintasaura'' indicates it had not yet diversified extensively from their ancestral anatomical state. Only later would ornithischians diverge into larger, more specialized animals with traits like [[osteoderms|armor]] and [[quadruped]]ality.<ref name=barrett2014/>
Like other early members of Ornithischia, it is assumed that ''Laquintasaura'' was a lithe [[bipedal]] animal. The largest femur among the bonebed is {{convert|90|mm|inch}} in length; assuming similar proportions to similar animals like ''[[Hypsilophodon]]'', ''[[Heterodontosaurus]]'', and ''[[Hexinlusaurus]]'', it was estimated the ''Laquintasaura'' individual could grow to around {{convert|1|m|ft}} in length. However, this individual was a subadult, and more fragmentary remains appear to belong to slightly larger animals. The small size and conservative skeletal anatomy of ''Laquintasaura'' indicates it had not yet diversified extensively from their ancestral anatomical state. Only later would ornithischians diverge into larger, more specialized animals with traits like [[osteoderms|armor]] and [[quadruped]]ality.<ref name=barrett2014/>
[[File:Laquintasaura MBLUZ P.1396.png|thumb|alt=Diagram of tooth|[[Holotype]] tooth of ''Laquintasaura'', showing its distinct triangular shape]]
[[File:Laquintasaura MBLUZ P.1396.png|thumb|alt=Diagram of tooth|[[Holotype]] tooth of ''Laquintasaura'', showing its distinct triangular shape]]
The most distinctive anatomy of ''Laquintasaura'' is found in its [[dentition]]. The teeth are unusually tall and have their widest point immediately above the [[tooth root]]; the result of this is an [[isoceles triangle]] shape. Coarse [[Denticle (tooth feature)|denticles]] run along the entire crown margin (the edge of the exposed tooth). By comparison, the teeth of other primitive ornithischians have a stouter, sub-triangular shape that continues to widen farther up the tooth and only possesses denticles along the top of the crown. Additionally, the teeth of ''Laquintasaura'' possess uniquely prominent striations on both the inside and outside sides of the tooth. As opposed to the [[heterodont]] condition of later ornithischians, this dental anatomy is thought to have been uniform throughout the entirety of the mouth, both in the {{dinogloss|premaxilla}} and the {{dinogloss|maxilla}}. Some teeth are, however, somewhat more recurved than others.<ref name=barrett2014/> Convergently similar anatomy, with a tall tooth construction and striations, does occur [[convergent evolution|convergently]] in the [[neornithischia]]n dinosaur ''[[Hexinlusaurus]]'', which nonetheless has a differing tooth shape and denticulation.<ref name=barrett2014/><ref name=prasad2020/> The {{dinogloss|premaxilla}} of ''L. venezuelae'' has seven teeth in each position and does not present a [[diastema]] close to the premaxillo-maxillary suture. Such a high number of premaxillary teeth is uncommon in ornithischians, outside of some members of [[Ankylosauria]]. The high count in ''Laquintasaura'' elucidates the basal evolution state of Ornithischia, and indicates the species' dental anatomy is very primitive even compared to other [[Early Jurassic]] [[taxa]].<ref name=herrera-castillo2021>{{cite journal |last1=Herrera-Castillo |first1=Carlos M. |last2= Carrillo-Briceño |first2=Jorge D. |last3= Sánchez-Villagra |first3=Marcelo R. |date=2021|title=Non-invasive imaging reveals new cranial element of the basal ornithischian dinosaur ''Laquintasaura venezuelae'', Early Jurassic of Venezuela | url=https://zenodo.org/records/5571307 | journal=[[Anartia]] |volume=32 |pages=53–60 |doi=10.5281/zenodo.5571307}}</ref>
The most distinctive anatomy of ''Laquintasaura'' is found in its [[dentition]]. The teeth are unusually tall and have their widest point immediately above the [[tooth root]]; the result of this is an [[isoceles triangle]] shape. Coarse [[Denticle (tooth feature)|denticles]] run along the entire crown margin (the edge of the exposed tooth). By comparison, the teeth of other primitive ornithischians have a stouter, sub-triangular shape that continues to widen farther up the tooth and only possesses denticles along the top of the crown. Additionally, the teeth of ''Laquintasaura'' possess uniquely prominent striations on both the inside and outside sides of the tooth. As opposed to the [[heterodont]] condition of later ornithischians, this dental anatomy is thought to have been uniform throughout the entirety of the mouth, both in the {{dinogloss|premaxilla}} and the {{dinogloss|maxilla}}. Some teeth are, however, somewhat more recurved than others.<ref name=barrett2014/> Convergently similar anatomy, with a tall tooth construction and striations, does occur [[convergent evolution|convergently]] in the [[neornithischia]]n dinosaur ''[[Hexinlusaurus]]'', which nonetheless has a differing tooth shape and denticulation.<ref name=barrett2014/><ref name=prasad2020/> The {{dinogloss|premaxilla}} of ''L. venezuelae'' has seven teeth in each position and does not present a [[diastema]] close to the premaxillo-maxillary suture. Such a high number of premaxillary teeth is uncommon in ornithischians, outside of some members of [[Ankylosauria]]. The high count in ''Laquintasaura'' elucidates the basal evolution state of Ornithischia, and indicates the species' dental anatomy is very primitive even compared to other [[Early Jurassic]] [[taxa]].<ref name=herrera-castillo2021>{{cite journal |last1=Herrera-Castillo |first1=Carlos M. |last2= Carrillo-Briceño |first2=Jorge D. |last3= Sánchez-Villagra |first3=Marcelo R. |date=2021|title=Non-invasive imaging reveals new cranial element of the basal ornithischian dinosaur Laquintasaura venezuelae, Early Jurassic of Venezuela |journal=[[Anartia]] |volume=32 |pages=53–60 |doi=10.5281/zenodo.5571307}}</ref>
Though less distinctive than the dentition, the [[postcranium]] also possesses distinguishing traits. The upper surface of the {{dinogloss|ischium}} further up than the {{dinogloss|obturator process}} is highly inflected; in closely related taxa both sides of the ischium form a more continuous, smooth surface. The [[epicondyle]] at the connection of the {{dinogloss|femur}} and the {{dinogloss|fibula}} is inset in the middle from a ventral or posterior view, a derived trait lacking in other primitive taxa, which possess a smooth transition without any notch forming a "step". Finally, the {{dinogloss|astragalus}} has a broad and deep U-shaped notch on its top surface; a similar V-shaped notch is seen in ''[[Scutellosaurus]]'', but is less than half as deep. In contrast to these unique traits, ornithischian [[synapomorphies]] can be seen in the pelvic anatomy. In addition to its diagnostic features, numerous differences from other individual basal ornithischian taxa were noted, described in detail in the supplementary material of the 2014 description paper.<ref name=barrett2014/> A later 2022 study by David Norman and colleagues concerning ornithischian evolution noted features not described in the initial publication. They brought attention to the backward-pointing pubis, as ''Laquintasaura'' is the oldest known ornithischian with this trait, which has traditionally been considered a key identifier of the origin of Ornithischia alongside the evolution of the {{dinogloss|predentary}} bone, unpreserved in ''Laquintasaura''. Furthermore, they noted its [[femur|femoral]] anatomy may be intermediate to that of Triassic [[silesauridae|silesaurs]] and Jurassic [[ornithischia]]ns. Its {{dinogloss|fourth trochanter}} is wider and lacking in protrusion than other Jurassic taxa, but is more strongly developed than the shallow crest seen in silesaurs. Similarly, the head of the femur has flat shape as in silesaurs (strongly rounded in other taxa), but projects inwards relative to the femoral shaft as in Jurassic species.<ref name=norman2022>{{cite journal | url=https://academic.oup.com/zoolinnean/article/196/4/1273/6680019 | title=Taxonomic, palaeobiological and evolutionary implications of a phylogenetic hypothesis for Ornithischia (Archosauria: Dinosauria) | journal=[[Zoological Journal of the Linnean Society]] | last1=Norman | first1=David B. | last2=Baron | first2=Matthew G. | last3=Garcia | first3=Mauricio S. | last4=Müller | first4=Rodrigo Temp | year=2022 | volume=196 | issue=4 | pages=1273–1309 | doi=10.1093/zoolinnean/zlac062}}</ref>
Though less distinctive than the dentition, the [[postcranium]] also possesses distinguishing traits. The upper surface of the {{dinogloss|ischium}} further up than the {{dinogloss|obturator process}} is highly inflected; in closely related taxa both sides of the ischium form a more continuous, smooth surface. The [[epicondyle]] at the connection of the {{dinogloss|femur}} and the {{dinogloss|fibula}} is inset in the middle from a ventral or posterior view, a derived trait lacking in other primitive taxa, which possess a smooth transition without any notch forming a "step". Finally, the {{dinogloss|astragalus}} has a broad and deep U-shaped notch on its top surface; a similar V-shaped notch is seen in ''[[Scutellosaurus]]'', but is less than half as deep. In contrast to these unique traits, ornithischian [[synapomorphies]] can be seen in the pelvic anatomy. In addition to its diagnostic features, numerous differences from other individual basal ornithischian taxa were noted, described in detail in the supplementary material of the 2014 description paper.<ref name=barrett2014/> A later 2022 study by David Norman and colleagues concerning ornithischian evolution noted features not described in the initial publication. They brought attention to the backward-pointing pubis, as ''Laquintasaura'' is the oldest known ornithischian with this trait, which has traditionally been considered a key identifier of the origin of Ornithischia alongside the evolution of the {{dinogloss|predentary}} bone, unpreserved in ''Laquintasaura''. Furthermore, they noted its [[femur|femoral]] anatomy may be intermediate to that of Triassic [[silesauridae|silesaurs]] and Jurassic [[ornithischia]]ns. Its {{dinogloss|fourth trochanter}} is wider and lacking in protrusion than other Jurassic taxa, but is more strongly developed than the shallow crest seen in silesaurs. Similarly, the head of the femur has flat shape as in silesaurs (strongly rounded in other taxa), but projects inwards relative to the femoral shaft as in Jurassic species.<ref name=norman2022>{{cite journal | url=https://academic.oup.com/zoolinnean/article/196/4/1273/6680019 | title=Taxonomic, palaeobiological and evolutionary implications of a phylogenetic hypothesis for Ornithischia (Archosauria: Dinosauria) | journal=[[Zoological Journal of the Linnean Society]] | last1=Norman | first1=David B. | last2=Baron | first2=Matthew G. | last3=Garcia | first3=Mauricio S. | last4=Müller | first4=Rodrigo Temp | year=2022 | volume=196 | issue=4 | pages=1273–1309 | doi=10.1093/zoolinnean/zlac062}}</ref>
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==Classification==
[[File:Scutellosaurus_skeleton.jpg|thumb|alt=Possible relative ''[[Scutellosaurus]]''|Thyreophoran ''[[Scutellosaurus]]''; ''Laquintasaura'' may have been an early member of the [[Thyreophora|armored dinosaur]] lineage]]
[[File:Scutellosaurus_skeleton.jpg|thumb|alt=Possible relative ''[[Scutellosaurus]]''|Thyreophoran ''[[Scutellosaurus]]''; ''Laquintasaura'' may have been an early member of the [[Thyreophora|armored dinosaur]] lineage]]
The [[phylogenetic]] relationships of ''Laquintasaura'' remains somewhat uncertain.<ref name=yao2022>{{Cite journal |last1=Yao |first1=X. |last2=Barrett |first2=P. M. |last3=Lei |first3=Y. |last4=Xu |first4=X. |last5=Bi |first5=S. |date=2022-03-15 |title=A new early-branching armoured dinosaur from the Lower Jurassic of southwestern China |journal=[[eLife]] |volume=11 |pages=e75248 |doi=10.7554/eLife.75248 |doi-access=free |pmid=35289749 |pmc=8929930 }}</ref><ref name=breeden2020>{{cite journal |url=https://www.tandfonline.com/doi/full/10.1080/02724634.2020.1791894 |title=New Specimens of ''Scutellosaurus Lawleri'' Colbert, 1981, from the Lower Jurassic Kayenta Formation in Arizona Elucidate the Early Evolution of Thyreophoran Dinosaurs |last1=Breeden III |first1=Bejamin T. |last2=Rowe |first2=Timothy B. |journal=[[Journal of Vertebrate Paleontology]] |year=2020 |volume=40 |issue=4 |pages=e1791894 |doi=10.1080/08912963.2020.1793979|bibcode=2021HBio...33.2335D }}</ref><ref name=breeden2021>{{cite journal |title=The anatomy and palaeobiology of the early armoured dinosaur ''Scutellosaurus lawleri'' (Ornithischia: Thyreophora) from the Kayenta Formation (Lower Jurassic) of Arizona |last1=Breeden III |first1=Benjamin T. |last2=Raven |first2=Thomas J. |last3=Butler |first3=Richard J. |last4=Rowe |first4=Timothy B. |last5=Maidment |first5=Susannah C. R. |journal=[[Royal Society Open Science]] |year=2021 |volume=8 |issue=7 |doi=10.1098/rsos.201676|doi-access=free |pmid=34295511 |pmc=8292774 |bibcode=2021RSOS....801676B }}</ref> It is robustly considered a basal member of the group [[Ornithischia]], but its exact position within this clade are unresolved. The original 2014 description found it in a large [[polytomy]] with ''[[Eocursor]]'', ''[[Lesothosaurus]]'', ''[[Stormbergia]]'', ''[[Scutellosaurus]]'', the clade [[Thyreophora]], and the clade [[Neornithischia]].<ref name=barrett2014/> Some later phylogenetic analyses have had to remove the taxon from [[phylogenetic analyses]] outright due to being too fragmentary and lowering the resolution of the results.<ref name=Han2017>{{Cite journal |first1=Fenglu |last1=Han |first2=Catherine A. |last2=Forster |first3=Xing |last3=Xu |first4=James M. |last4=Clark |year=2017 |url=https://www.tandfonline.com/doi/full/10.1080/14772019.2017.1369185 | title=Postcranial anatomy of ''Yinlong downsi'' (Dinosauria: Ceratopsia) from the Upper Jurassic Shishugou Formation of China and the phylogeny of basal ornithischians |journal=[[Journal of Systematic Palaeontology]] |volume=16 |issue=14 |pages=1159–1187 |doi=10.1080/14772019.2017.1369185 |s2cid=90051025}}</ref><ref name=yang2020>{{cite journal |last1=Yang |first1=Y. |last2=Wu |first2=W. |last3=Dieudonné |first3=P. |last4=Godefroit |first4=P. |title=A new basal ornithopod dinosaur from the Lower Cretaceous of China |journal=PeerJ |date=2020 |volume=8 |page=e9832 |doi=10.7717/peerj.9832|pmid=33194351 |pmc=7485509 |doi-access=free }}</ref> Some studies, such as that of Matthew G. Baron and David Norman or that of Thomas J. Raven and [[Susannah Maidment]], both in 2017, have found it to be a very early member of the group Thyreophora (armored dinosaurs), as the [[sister taxon]] of ''Scutellosaurus''.<ref name=baron2017>{{Cite journal |last1=Baron |first1=Matthew G. |last2=Norman |first2=David B. |last3=Barrett |first3=Paul M. |date=2017-01-01 |title=Postcranial anatomy of ''Lesothosaurus diagnosticus'' (Dinosauria: Ornithischia) from the Lower Jurassic of southern Africa: implications for basal ornithischian taxonomy and systematics |journal=Zoological Journal of the Linnean Society |volume=179 |issue=1 |pages=125–168 |doi=10.1111/zoj.12434 |issn=0024-4082|doi-access=free }}</ref><ref name=maidment2017>{{cite journal |last1=Raven |first1=T.j. |last2=Maidment |first2=S.C.R. |year=2017 |title=A new phylogeny of Stegosauria (Dinosauria, Ornithischia) |journal=[[Palaeontology (journal)|Palaeontology]] |volume=2017 |issue=3 |pages=401–408 |doi=10.1111/pala.12291 |bibcode=2017Palgy..60..401R |url=http://eprints.brighton.ac.uk/16844/1/Raven%26Maidment_AcceptedPreprint.pdf|hdl=10044/1/45349|s2cid=55613546 |hdl-access=free}}</ref> Bone histology, similar to ''Scutellosaurus'' but unlike ''Lesothosaurus'', has been posited as circumstantial evidence of this placement.<ref name="botha2022">{{cite journal |url=https://onlinelibrary.wiley.com/doi/10.1111/pala.12619 |title=Osteohistology and taphonomy support social aggregation in the early ornithischian dinosaur ''Lesothosaurus diagnosticus'' |last1=Botha |first1=Jennifer |last2=Choiniere |first2=Jonah N. |last3=Barrett |first3=Paul M. |journal=[[Palaeontology (journal)|Palaeontology]] |year=2022 |volume=65 |issue=4 |pages=e12619 |doi=10.1111/pala.12619|bibcode=2022Palgy..6512619B }}</ref> The analysis of a study on ornithischian phylogeny by P. E. Dieudonné and colleagues in 2021 instead found ''Laquintasaura'' in a more primitive position outside of the clade [[Genasauria]].<ref name=dieudonne2021>{{cite journal |last1=Dieudonné |first1=P.E. |last2=Cruzado-Caballero |first2=P. |last3=Godefroit |first3=P. |last4=Tortosa |first4=T. |title=A new phylogeny of cerapodan dinosaurs |journal=[[Historical Biology]] |date=2021 |volume=33 |issue=10 |pages=2335–2355 |doi=10.1080/08912963.2020.1793979|doi-access=free |bibcode=2021HBio...33.2335D }}</ref> Similarly, a 2022 study by Baron, Norman, and colleagues found it to be outside of the clade [[Prionodontia]] (known [[Saphornithischia]] under alternative nomenclatural schemes<ref name="fonseca2024">{{cite journal|last1=Fonseca|first1=A.O.|last2=Reid|first2=I.J.|last3=Venner|first3=A.|last4=Duncan|first4=R.J.|last5=Garcia|first5=M.S.|last6=Müller|first6=R.T.|year=2024|url=https://www.tandfonline.com/doi/full/10.1080/14772019.2024.2346577|title=A comprehensive phylogenetic analysis on early ornithischian evolution|journal=[[Journal of Systematic Palaeontology]]|volume=22|issue=1|pages=2346577|doi=10.1080/14772019.2024.2346577|bibcode=2024JSPal..2246577F }}</ref>), intermediate between the traditional scope of Ornithischia and an [[evolutionary grade|grade]] of animals that traditionally compose [[Silesauridae]].<ref name=norman2022/> A comprehensive study on the classification of early ornithischians by André Fonseca and colleagues found positions within Thyreophora and outside of Genasauria to be plausible, and highlighted the fact the taxon has only received a preliminary description as a factor in its instability.<ref name=fonseca2024/>
The [[phylogenetic]] relationships of ''Laquintasaura'' remains somewhat uncertain.<ref name=yao2022>{{Cite journal |last1=Yao |first1=X. |last2=Barrett |first2=P. M. |last3=Lei |first3=Y. |last4=Xu |first4=X. |last5=Bi |first5=S. |date=2022-03-15 |title=A new early-branching armoured dinosaur from the Lower Jurassic of southwestern China |journal=[[eLife]] |volume=11 |pages=e75248 |doi=10.7554/eLife.75248 |doi-access=free |pmid=35289749 |pmc=8929930 }}</ref><ref name=breeden2020>{{cite journal |url=https://www.tandfonline.com/doi/full/10.1080/02724634.2020.1791894 |title=New Specimens of Scutellosaurus Lawleri Colbert, 1981, from the Lower Jurassic Kayenta Formation in Arizona Elucidate the Early Evolution of Thyreophoran Dinosaurs |last1=Breeden III |first1=Bejamin T. |last2=Rowe |first2=Timothy B. |journal=[[Journal of Vertebrate Paleontology]] |year=2020 |volume=40 |issue=4 |pages=e1791894 |doi=10.1080/08912963.2020.1793979|bibcode=2021HBio...33.2335D }}</ref><ref name=breeden2021>{{cite journal |title=The anatomy and palaeobiology of the early armoured dinosaur Scutellosaurus lawleri (Ornithischia: Thyreophora) from the Kayenta Formation (Lower Jurassic) of Arizona |last1=Breeden III |first1=Benjamin T. |last2=Raven |first2=Thomas J. |last3=Butler |first3=Richard J. |last4=Rowe |first4=Timothy B. |last5=Maidment |first5=Susannah C. R. |journal=[[Royal Society Open Science]] |year=2021 |volume=8 |issue=7 |doi=10.1098/rsos.201676|doi-access=free |pmid=34295511 |pmc=8292774 |bibcode=2021RSOS....801676B }}</ref> It is robustly considered a basal member of the group [[Ornithischia]], but its exact position within this clade are unresolved. The original 2014 description found it in a large [[polytomy]] with ''[[Eocursor]]'', ''[[Lesothosaurus]]'', ''[[Stormbergia]]'', ''[[Scutellosaurus]]'', the clade [[Thyreophora]], and the clade [[Neornithischia]].<ref name=barrett2014/> Some later phylogenetic analyses have had to remove the taxon from [[phylogenetic analyses]] outright due to being too fragmentary and lowering the resolution of the results.<ref name=Han2017>{{Cite journal |first1=Fenglu |last1=Han |first2=Catherine A. |last2=Forster |first3=Xing |last3=Xu |first4=James M. |last4=Clark |year=2017 |title=Postcranial anatomy of ''Yinlong downsi'' (Dinosauria: Ceratopsia) from the Upper Jurassic Shishugou Formation of China and the phylogeny of basal ornithischians |journal=[[Journal of Systematic Palaeontology]] |volume=16 |issue=14 |pages=1159–1187 |doi=10.1080/14772019.2017.1369185 |s2cid=90051025}}</ref><ref name=yang2020>{{cite journal |last1=Yang |first1=Y. |last2=Wu |first2=W. |last3=Dieudonné |first3=P. |last4=Godefroit |first4=P. |title=A new basal ornithopod dinosaur from the Lower Cretaceous of China |journal=PeerJ |date=2020 |volume=8 |page=e9832 |doi=10.7717/peerj.9832|pmid=33194351 |pmc=7485509 |doi-access=free }}</ref> Some studies, such as that of Matthew G. Baron and David Norman or that of Thomas J. Raven and [[Susannah Maidment]], both in 2017, have found it to be a very early member of the group Thyreophora (armored dinosaurs), as the [[sister taxon]] of ''Scutellosaurus''.<ref name=baron2017>{{Cite journal |last1=Baron |first1=Matthew G. |last2=Norman |first2=David B. |last3=Barrett |first3=Paul M. |date=2017-01-01 |title=Postcranial anatomy of ''Lesothosaurus diagnosticus'' (Dinosauria: Ornithischia) from the Lower Jurassic of southern Africa: implications for basal ornithischian taxonomy and systematics |journal=Zoological Journal of the Linnean Society |volume=179 |issue=1 |pages=125–168 |doi=10.1111/zoj.12434 |issn=0024-4082|doi-access=free }}</ref><ref name=maidment2017>{{cite journal |last1=Raven |first1=T.j. |last2=Maidment |first2=S.C.R. |year=2017 |title=A new phylogeny of Stegosauria (Dinosauria, Ornithischia) |journal=[[Palaeontology (journal)|Palaeontology]] |volume=2017 |issue=3 |pages=401–408 |doi=10.1111/pala.12291 |bibcode=2017Palgy..60..401R |url=http://eprints.brighton.ac.uk/16844/1/Raven%26Maidment_AcceptedPreprint.pdf|hdl=10044/1/45349|s2cid=55613546 |hdl-access=free}}</ref> Bone histology, similar to ''Scutellosaurus'' but unlike ''Lesothosaurus'', has been posited as circumstantial evidence of this placement.<ref name="botha2022">{{cite journal |url=https://onlinelibrary.wiley.com/doi/10.1111/pala.12619 |title=Osteohistology and taphonomy support social aggregation in the early ornithischian dinosaur Lesothosaurus diagnosticus |last1=Botha |first1=Jennifer |last2=Choiniere |first2=Jonah N. |last3=Barrett |first3=Paul M. |journal=[[Palaeontology (journal)|Palaeontology]] |year=2022 |volume=65 |issue=4 |pages=e12619 |doi=10.1111/pala.12619|bibcode=2022Palgy..6512619B }}</ref> The analysis of a study on ornithischian phylogeny by P. E. Dieudonné and colleagues in 2021 instead found ''Laquintasaura'' in a more primitive position outside of the clade [[Genasauria]].<ref name=dieudonne2021>{{cite journal |last1=Dieudonné |first1=P.E. |last2=Cruzado-Caballero |first2=P. |last3=Godefroit |first3=P. |last4=Tortosa |first4=T. |title=A new phylogeny of cerapodan dinosaurs |journal=[[Historical Biology]] |date=2021 |volume=33 |issue=10 |pages=2335–2355 |doi=10.1080/08912963.2020.1793979|doi-access=free |bibcode=2021HBio...33.2335D }}</ref> Similarly, a 2022 study by Baron, Norman, and colleagues found it to be outside of the clade [[Prionodontia]] (known [[Saphornithischia]] under alternative nomenclatural schemes<ref name="fonseca2024">{{cite journal|last1=Fonseca|first1=A.O.|last2=Reid|first2=I.J.|last3=Venner|first3=A.|last4=Duncan|first4=R.J.|last5=Garcia|first5=M.S.|last6=Müller|first6=R.T.|year=2024|title=A comprehensive phylogenetic analysis on early ornithischian evolution|journal=[[Journal of Systematic Palaeontology]]|volume=22|issue=1|pages=2346577|doi=10.1080/14772019.2024.2346577|bibcode=2024JSPal..2246577F }}</ref>), intermediate between the traditional scope of Ornithischia and an [[evolutionary grade|grade]] of animals that traditionally compose [[Silesauridae]].<ref name=norman2022/> A comprehensive study on the classification of early ornithischians by André Fonseca and colleagues found positions within Thyreophora and outside of Genasauria to be plausible, and highlighted the fact the taxon has only received a preliminary description as a factor in its instability.<ref name=fonseca2024/>
The cladogram from Baron ''et al.'' (2017) is shown immediately below, and that of Norman ''et al.'' (2022) is shown at the bottom. [[Clade]] names have been inserted based on definitions established by a paper by Daniel Madzia and colleagues in 2021 for clarity.<ref name=baron2017/><ref name=dieudonne2021/><ref name=madzia2021>{{cite journal |last1=Madzia |first1=D. |last2=Arbour |first2=V.M. |last3=Boyd |first3=C.A. |last4=Farke |first4=A.A. |last5=Cruzado-Caballero |first5=P. |last6=Evans |first6=D.C. |year=2021 |title=The phylogenetic nomenclature of ornithischian dinosaurs |journal=[[PeerJ]] |volume=9 |pages=e12362 |doi=10.7717/peerj.12362 |pmid=34966571 |pmc=8667728 |doi-access=free }}</ref>
The cladogram from Baron ''et al.'' (2017) is shown immediately below, and that of Norman ''et al.'' (2022) is shown at the bottom. [[Clade]] names have been inserted based on definitions established by a paper by Daniel Madzia and colleagues in 2021 for clarity.<ref name=baron2017/><ref name=dieudonne2021/><ref name=madzia2021>{{cite journal |last1=Madzia |first1=D. |last2=Arbour |first2=V.M. |last3=Boyd |first3=C.A. |last4=Farke |first4=A.A. |last5=Cruzado-Caballero |first5=P. |last6=Evans |first6=D.C. |year=2021 |title=The phylogenetic nomenclature of ornithischian dinosaurs |journal=[[PeerJ]] |volume=9 |pages=e12362 |doi=10.7717/peerj.12362 |pmid=34966571 |pmc=8667728 |doi-access=free }}</ref>
Line 111: Line 111:''Laquintasaura'' hails from the La Quinta Formation in what is now Colombia and Venezuela, found in the Venezuelan part of the formation.<ref name=barrett2014/><ref name=rincon2022/> The exact age of the La Quinta Formation was traditionally very unclear, but modern estimates find that the section containing the ''Laquintasaura'' bonebed dates to the [[Hettangian]] age of the [[Early Jurassic]] epoch, around 200 million years ago and potentially as little as one hundred and fifty thousand years from the end of the [[Triassic]] period.<ref name=langer2014/><ref name=barrett2014/><ref name=irmis2022>{{cite journal | url=https://www.sciencedirect.com/science/article/pii/S089598112200061X | title=South American Triassic geochronology: Constraints and uncertainties for the tempo of Gondwanan non-marine vertebrate evolution | journal=[[Journal of South American Earth Sciences]] | last1=Irmis | first1=Randall B. | last2=Mundil | first2=Roland | last3=Mancuso | first3=Adriana Cecilia | last4=Carrillo-Briceño | first4=Jorge D. | last5=Ottone | first5=Eduardo | last6=Marsicano | first6=Caudia A. | year=2022 | volume=116 | pages=10.1016/j.jsames.2022.103770| doi=10.1016/j.jsames.2022.103770 | bibcode=2022JSAES.11603770I }}</ref> This very old age makes ''Laquintasaura'' one of the earliest known members of Ornithischia, making it important to understanding their early evolution.<ref name=herrera-castillo2021/><ref name=barrett2014/> It provides concrete evidence that they had spread to the northern hemisphere by the start of the [[Jurassic]],<ref name=breeden2020/> and its geographic placement in an equatorial region demonstrates early dinosaur presence in equatorial latitudes, as well as such region's role in early dinosaur evolution, something traditionally doubted.<ref name=herrera-castillo2021/><ref name=barrett2014/><ref name=RoyalSocietyPressRelease /> Though the genus' presence so soon after the [[end-Triassic extinction]] indicates ornithischians achieved quick expansion in diversity and distribution, its conservative anatomy indicates that increases in body size and anatomical specialization did not occur until later in the [[Jurassic]].<ref name=barrett2014/>
''Laquintasaura'' hails from the La Quinta Formation in what is now Colombia and Venezuela, found in the Venezuelan part of the formation.<ref name=barrett2014/><ref name=rincon2022/> The exact age of the La Quinta Formation was traditionally very unclear, but modern estimates find that the section containing the ''Laquintasaura'' bonebed dates to the [[Hettangian]] age of the [[Early Jurassic]] epoch, around 200 million years ago and potentially as little as one hundred and fifty thousand years from the end of the [[Triassic]] period.<ref name=langer2014/><ref name=barrett2014/><ref name=irmis2022>{{cite journal | url=https://www.sciencedirect.com/science/article/pii/S089598112200061X | title=South American Triassic geochronology: Constraints and uncertainties for the tempo of Gondwanan non-marine vertebrate evolution | journal=[[Journal of South American Earth Sciences]] | last1=Irmis | first1=Randall B. | last2=Mundil | first2=Roland | last3=Mancuso | first3=Adriana Cecilia | last4=Carrillo-Briceño | first4=Jorge D. | last5=Ottone | first5=Eduardo | last6=Marsicano | first6=Caudia A. | year=2022 | volume=116 | pages=10.1016/j.jsames.2022.103770| doi=10.1016/j.jsames.2022.103770 | bibcode=2022JSAES.11603770I }}</ref> This very old age makes ''Laquintasaura'' one of the earliest known members of Ornithischia, making it important to understanding their early evolution.<ref name=herrera-castillo2021/><ref name=barrett2014/> It provides concrete evidence that they had spread to the northern hemisphere by the start of the [[Jurassic]],<ref name=breeden2020/> and its geographic placement in an equatorial region demonstrates early dinosaur presence in equatorial latitudes, as well as such region's role in early dinosaur evolution, something traditionally doubted.<ref name=herrera-castillo2021/><ref name=barrett2014/><ref name=RoyalSocietyPressRelease /> Though the genus' presence so soon after the [[end-Triassic extinction]] indicates ornithischians achieved quick expansion in diversity and distribution, its conservative anatomy indicates that increases in body size and anatomical specialization did not occur until later in the [[Jurassic]].<ref name=barrett2014/>
[[File:Lesothosaurus_sp_skull_3894.jpg|thumb|alt=Skull of relative ''[[Lesothosaurus]]''|Skull of ''[[Lesothosaurus]]'', another early [[ornithischia]]n; it may have shared omnivorous diet with ''Laquintasaura'' lost in later relatives]]
[[File:Lesothosaurus_sp_skull_3894.jpg|thumb|alt=Skull of relative ''[[Lesothosaurus]]''|Skull of ''[[Lesothosaurus]]'', another early [[ornithischia]]n; it may have shared omnivorous diet with ''Laquintasaura'' lost in later relatives]]
The ecosystem that ''Laquintasaura'' lived in is thought to represent an [[alluvial plain]], with both arid and humid seasons.<ref name=langer2014/> The early [[theropod]] dinosaur ''[[Tachiraptor]]'' would have lived alongside ''Laquintasaura'', and likely preyed upon it.<ref name=langer2014/><ref name=tachiraptorpress>{{cite news | url=https://www.sci.news/paleontology/science-tachiraptor-admirabilis-carnivorous-dinosaur-venezuela-02196.html | title=Tachiraptor admirabilis: New Carnivorous Dinosaur Unearthed in Venezuela | website=[[Sci-News]] | date=10 October 2014 | accessdate=August 12, 2022}}</ref> The [[sauropod]] dinosaur ''[[Perijasaurus]]'' also hails from the La Quinta Formation, but is thought to have lived at a later time near the end of the Early Jurassic, around 175 million years ago.<ref name=rincon2022>{{Cite journal |last1=Rincón |first1=Aldo F. |last2=Raad Pájaro |first2=Daniel A. |last3=Jiménez Velandia |first3=Harold F. |last4=Ezcurra |first4=Martín D. |last5=Wilson Mantilla |first5=Jeffrey A. |year=2022 |url=https://www.tandfonline.com/doi/full/10.1080/02724634.2021.2077112 |title=A sauropod from the Lower Jurassic La Quinta Formation (Dept. Cesar, Colombia) and the initial diversification of eusauropods at low latitudes |journal=[[Journal of Vertebrate Paleontology]] |volume=42 |issue=1 |pages=e2077112 |doi=10.1080/02724634.2021.2077112|bibcode=2022JVPal..42E7112R }}</ref> ''Laquintasaura'' is thought to have been primarily herbivorous, but the unusually tall structure of the teeth are reminiscent of carnivorous animals, indicating they may have also eaten things like small insects as part of their diet.<ref name=RoyalSocietyPressRelease>{{cite web |url=https://royalsociety.org/news/2014/new-dinosaur-discovered/ |title=New dinosaur discovered in Venezuela |date=6 August 2014 |website=[[Royal Society]] |access-date=7 August 2014 }}</ref><ref name="Huff Post" >{{cite web |
The ecosystem that ''Laquintasaura'' lived in is thought to represent an [[alluvial plain]], with both arid and humid seasons.<ref name=langer2014/> The early [[theropod]] dinosaur ''[[Tachiraptor]]'' would have lived alongside ''Laquintasaura'', and likely preyed upon it.<ref name=langer2014/><ref name=tachiraptorpress>{{cite news | url=https://www.sci.news/paleontology/science-tachiraptor-admirabilis-carnivorous-dinosaur-venezuela-02196.html | title=Tachiraptor admirabilis: New Carnivorous Dinosaur Unearthed in Venezuela | website=[[Sci-News]] | date=10 October 2014 | accessdate=August 12, 2022}}</ref> The [[sauropod]] dinosaur ''[[Perijasaurus]]'' also hails from the La Quinta Formation, but is thought to have lived at a later time near the end of the Early Jurassic, around 175 million years ago.<ref name=rincon2022>{{Cite journal |last1=Rincón |first1=Aldo F. |last2=Raad Pájaro |first2=Daniel A. |last3=Jiménez Velandia |first3=Harold F. |last4=Ezcurra |first4=Martín D. |last5=Wilson Mantilla |first5=Jeffrey A. |year=2022 |title=A sauropod from the Lower Jurassic La Quinta Formation (Dept. Cesar, Colombia) and the initial diversification of eusauropods at low latitudes |journal=[[Journal of Vertebrate Paleontology]] |volume=42 |issue=1 |pages=e2077112 |doi=10.1080/02724634.2021.2077112|bibcode=2022JVPal..42E7112R }}</ref> ''Laquintasaura'' is thought to have been primarily herbivorous, but the unusually tall structure of the teeth are reminiscent of carnivorous animals, indicating they may have also eaten things like small insects as part of their diet.<ref name=RoyalSocietyPressRelease>{{cite web |url=https://royalsociety.org/news/2014/new-dinosaur-discovered/ |title=New dinosaur discovered in Venezuela |date=6 August 2014 |website=[[Royal Society]] |access-date=7 August 2014 }}</ref><ref name="Huff Post" >{{cite web |
url=http://www.huffingtonpost.com/2014/08/06/dinosaur-discovered-venezuela_n_5654116.html |title=New Fox-Sized Dinosaur Unearthed In Venezuela |author=Charles Q. Choi |date=6 August 2014 |website=[[The Huffington Post]] |access-date=7 August 2014 }}</ref> Similar omnivorous behaviour has been suggested in the fellow primitive ornithischian ''[[Lesothosaurus]]'',<ref name=sciscio2017>{{Cite journal |last1=Sciscio |first1=Lara |last2=Knoll |first2=Fabien |last3=Bordy |first3=Emese M. |last4=Kock |first4=Michiel O. de |last5=Redelstorff |first5=Ragna |date=2017-03-01 |title=Digital reconstruction of the mandible of an adult ''Lesothosaurus diagnosticus'' with insight into the tooth replacement process and diet |journal=[[PeerJ]] |language=en |volume=5 |pages=e3054 |doi=10.7717/peerj.3054 |issn=2167-8359 |doi-access=free |pmid=28265518 |pmc=5335715 }}</ref> as well as more tentatively in taxa like ''[[Agilisaurus]]'', ''[[Hypsilophodon]]'', and ''[[Orodromeus]]'' before disappearing in more derived relatives such as [[iguanodontians]].<ref name=hubner2010>{{cite journal | url=https://academic.oup.com/zoolinnean/article-abstract/160/2/366/2627156 | title=A juvenile skull of ''Dysalotosaurus lettowvorbecki'' (Ornithischia: Iguanodontia), and implications for cranial ontogeny, phylogeny, and taxonomy in ornithopod dinosaurs | journal=[[Zoological Journal of the Linnean Society]] | last1=Hübner | first1=Tom R. | last2=Rauhut | first2=Oliver W.M.| year=2010 | volume=160 | issue=2 | pages=366–396 | doi=10.1111/j.1096-3642.2010.00620.x}}</ref>
url=http://www.huffingtonpost.com/2014/08/06/dinosaur-discovered-venezuela_n_5654116.html |title=New Fox-Sized Dinosaur Unearthed In Venezuela |author=Charles Q. Choi |date=6 August 2014 |website=[[The Huffington Post]] |access-date=7 August 2014 }}</ref> Similar omnivorous behaviour has been suggested in the fellow primitive ornithischian ''[[Lesothosaurus]]'',<ref name=sciscio2017>{{Cite journal |last1=Sciscio |first1=Lara |last2=Knoll |first2=Fabien |last3=Bordy |first3=Emese M. |last4=Kock |first4=Michiel O. de |last5=Redelstorff |first5=Ragna |date=2017-03-01 |title=Digital reconstruction of the mandible of an adult Lesothosaurus diagnosticus with insight into the tooth replacement process and diet |journal=[[PeerJ]] |language=en |volume=5 |pages=e3054 |doi=10.7717/peerj.3054 |issn=2167-8359 |doi-access=free |pmid=28265518 |pmc=5335715 }}</ref> as well as more tentatively in taxa like ''[[Agilisaurus]]'', ''[[Hypsilophodon]]'', and ''[[Orodromeus]]'' before disappearing in more derived relatives such as [[iguanodontians]].<ref name=hubner2010>{{cite journal | url=https://academic.oup.com/zoolinnean/article-abstract/160/2/366/2627156 | title=A juvenile skull of Dysalotosaurus lettowvorbecki (Ornithischia: Iguanodontia), and implications for cranial ontogeny, phylogeny, and taxonomy in ornithopod dinosaurs | journal=[[Zoological Journal of the Linnean Society]] | last1=Hübner | first1=Tom R. | last2=Rauhut | first2=Oliver W.M.| year=2010 | volume=160 | issue=2 | pages=366–396 | doi=10.1111/j.1096-3642.2010.00620.x}}</ref>
The [[taphonomy]] of the ''Laquintasaura'' bonebed remains incompletely studied. The remains are thought to have undergone some degree of low-energy transport, but the lack of any damage to the bones, or signs of plant root damage or insect boring holes, indicate the remains were not exposed for a long time prior to burial.<ref name=barrett2014/> The bonebed is entirely devoid of microfossils, invertebrates, or plant remains, and is [[palynology|palynologically]] barren; the only other animal found at the site is the scant remains of ''[[Tachiraptor]]''.<ref name=langer2014/><ref name=barrett2014/> All of this indicates the four or more individuals at the site likely died together and maybe have lived together in life, indicative of social behaviour. Herding is known in ornithischians of the [[Late Jurassic]] and [[Cretaceous]], but its presence in ''Laquintasaura'' would be the first recognized in such an early member of the group (though more recent research has also indicated presence in the genus ''Lesothosaurus'').<ref name=barrett2014/><ref name="botha2022" />
The [[taphonomy]] of the ''Laquintasaura'' bonebed remains incompletely studied. The remains are thought to have undergone some degree of low-energy transport, but the lack of any damage to the bones, or signs of plant root damage or insect boring holes, indicate the remains were not exposed for a long time prior to burial.<ref name=barrett2014/> The bonebed is entirely devoid of microfossils, invertebrates, or plant remains, and is [[palynology|palynologically]] barren; the only other animal found at the site is the scant remains of ''[[Tachiraptor]]''.<ref name=langer2014/><ref name=barrett2014/> All of this indicates the four or more individuals at the site likely died together and maybe have lived together in life, indicative of social behaviour. Herding is known in ornithischians of the [[Late Jurassic]] and [[Cretaceous]], but its presence in ''Laquintasaura'' would be the first recognized in such an early member of the group (though more recent research has also indicated presence in the genus ''Lesothosaurus'').<ref name=barrett2014/><ref name="botha2022" />