Gorgetosuchus

{{Short description|Extinct genus of reptiles}} {{Automatic taxobox | taxon = Gorgetosuchus | fossil_range = [[Late Triassic]] | authority = Heckert ''et al.'', [[2015 in paleontology|2015]] | type_species = {{extinct}}'''''Gorgetosuchus pekinensis''''' | type_species_authority = Heckert ''et al.'', 2015 }}

'''''Gorgetosuchus''''' is an [[extinct]] [[genus]] of [[aetosaur]] from the [[Late Triassic]] of the [[North Carolina]], represented by the [[type species]] '''''Gorgetosuchus pekinensis'''''. It is mainly known from [[Osteoderm|osteoderms]], including the front half of an articulated [[carapace]].<ref name="HSFW15" /> ''Gorgotesuchus'' is typically considered a basal [[Desmatosuchini|desmatosuchin]],<ref name="HSFW15" /><ref name=":0">{{Cite journal|last=Parker|first=William G.|date=2016-01-21|title=Revised phylogenetic analysis of the Aetosauria (Archosauria: Pseudosuchia); assessing the effects of incongruent morphological character sets|journal=PeerJ|language=en|volume=4|article-number=e1583|doi=10.7717/peerj.1583|pmid=26819845 |pmc=4727975 |issn=2167-8359 |doi-access=free }}</ref> though alternative interpretations exist.<ref name=":1">{{Cite journal|last1=Hoffman|first1=Devin K.|last2=Heckert|first2=Andrew B.|last3=Zanno|first3=Lindsay E.|date=2018-02-13|title=Under the armor: X-ray computed tomographic reconstruction of the internal skeleton of ''Coahomasuchus chathamensis'' (Archosauria: Aetosauria) from the Upper Triassic of North Carolina, USA, and a phylogenetic analysis of Aetosauria|journal=PeerJ|language=en|volume=6|article-number=e4368|doi=10.7717/peerj.4368|pmid=29456892 |pmc=5815331 |issn=2167-8359 |doi-access=free }}</ref>

== Discovery == ''G. pekinensis'' was named and described by Heckert ''et al.'' (2015) on the basis of ten rows of bony plates called [[osteoderm]]s, representing the front part of an armored [[carapace]] that would have covered the back of the animal. These plates were found embedded in [[sandstone]] and [[conglomerate (geology)|conglomerate]] boulders near a brick quarry in [[Chatham County, North Carolina]], which likely originated from the Late Triassic [[Pekin Formation]]. (The Pekin Formation consists of interbedded red [[mudstone]]s, [[siltstone]]s, sandstones and conglomerates; it was the fine-grained mudstones and siltstones that the mining operation was targeting for [[brick-making]], so coarser-grained blocks were removed from the pit). ''Gorgetosuchus'' was part of a diverse faunal community in a continental [[rift valley]] system during the Late Triassic, which also included [[traversodontid]]s, [[phytosaur]]s, [[dicynodont]]s, and [[temnospondyl]]s. ''Gorgetosuchus'' coexisted with two other aetosaurs, ''[[Lucasuchus]]'' and ''[[Coahomasuchus]]''.<ref name="HSFW15">{{Cite journal | doi = 10.1080/02724634.2014.881831| title = A new aetosaur (Archosauria, Suchia) from the Upper Triassic Pekin Formation, Deep River Basin, North Carolina, U.S.A., and its implications for early aetosaur evolution| journal = Journal of Vertebrate Paleontology| volume = 35| article-number = e881831| year = 2015| last1 = Heckert | first1 = A. B. | last2 = Schneider | first2 = V. P. | last3 = Fraser | first3 = N. C. | last4 = Webb | first4 = R. A. | s2cid = 140176110| url = https://figshare.com/articles/dataset/A_new_aetosaur_Archosauria_Suchia_from_the_Upper_Triassic_Pekin_Formation_Deep_River_Basin_North_Carolina_U_S_A_and_its_implications_for_early_aetosaur_evolution/1294140| url-access = subscription}}</ref>

== Description == ''Gorgetosuchus'' is unique among aetosaurs in having cervical (neck) osteoderms that nearly wrap around the entire neck and are strongly angled to give the neck a hexagonal shape in cross-section. The lateral (side) and paramedian (upper) osteoderms each bear prominent spines. Other aetosaurs such as ''[[Longosuchus]]'' also have neck spines, but only on the lateral osteoderms. The cervical osteoderms are wider than they are long, a feature that unites ''Gorgetosuchus'' with [[basal (phylogenetics)|basal]] "[[Aetosaurinae|aetosaurine]]" aetosaurs. However, several features of the osteoderms (such as a flange on the lateral cervical osteoderms that overlaps the paramedian osteoderms) link it with the [[desmatosuchine]]s, a more [[derived (phylogenetics)|derived]] group of aetosaurs.

== Classification == Among aetosaurs, ''Gorgetosuchus'' closely resembles ''Lucasuchus'' and ''Longosuchus'', both of which are desmatosuchines. A [[phylogenetic analysis]] conducted by Heckert ''et al.'' (2015) placed ''Gorgetosuchus'' close to these taxa as the most basal desmatosuchine, but the results were not statistically well supported. Below is a [[computational phylogenetics|strict consensus tree]] from their analysis showing the placement of ''Gorgetosuchus'':<ref name="HSFW15" />

{{clade| style=font-size:90%;line-height:85% |1={{clade |1=''[[Postosuchus]]'' |2={{clade |1=''[[Revueltosaurus]]'' |2={{clade |label1=[[Aetosauria]] |1={{clade |1=''[[Aetosauroides]]'' |label2=[[Stagonolepididae]] |2={{clade |1=''[[Coahomasuchus]]'' |2={{clade |1=''[[Aetosaurus]]'' |2={{clade |1=''[[Neoaetosauroides]]'' |2={{clade |1=''[[Stagonolepis]]'' |2={{clade |1=''[[Calyptosuchus]]'' |2={{clade |1=''[[Redondasuchus]]'' |2={{clade |label1=[[Typothoracisinae]] |1={{clade |1=''[[Typothorax]]'' |2={{clade |1=''[[Tecovasuchus]]'' |2={{clade |1=''[[Paratypothorax]]'' |2=''[[Rioarribasuchus]]''}} }} }} |label2=[[Desmatosuchinae]] |2={{clade |1='''''Gorgetosuchus''''' |2={{clade |1=''[[Longosuchus]]'' |2={{clade |1=''[[Sierritasuchus]]'' |2={{clade |1=''[[Acaenasuchus]]'' |2={{clade |1=''[[Lucasuchus]]'' |2=''[[Desmatosuchus]]'' }} }} }} }} }} }} }} }} }} }} }} }} }} }} }} }} }} ''Gorgetosuchus'' was also placed as the basal-most member of [[Desmatosuchini]] (traditional desmatosuchines) in an analysis by Parker (2016).<ref name=":0" /> However, an analysis by Hoffman ''et al.'' (2018), based on an earlier analysis by Schoch & Desojo (2016), placed it within [[Typothoracinae]], closely related to ''[[Typothorax]]'' and ''[[Redondasuchus]]''. Typothoracines and desmatosuchins are known to have a large degree of [[homoplasy]] (convergent evolution) in certain osteoderm traits observed in ''Gorgetosuchus''. On the other hand, other skeletal traits strongly diverge between the two groups, so the position of ''Gorgetosuchus'' would likely stabilize if more non-osteoderm bones were discovered.<ref name=":1" />

==References== {{Reflist}}

[[Category:Aetosaurs of North America]] [[Category:Fossil taxa described in 2015]] [[Category:Late Triassic pseudosuchians]] [[Category:Fossils of North Carolina]] [[Category:Prehistoric pseudosuchian genera]]