Biology:Mongolostegus: Difference between revisions
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'''''Mongolostegus''''' (meaning "Mongolian roof") is an extinct genus of stegosaurian dinosaurs from the [[Earth:Early Cretaceous|Early Cretaceous]] ([[Earth:Aptian|Aptian]]–[[Earth:Albian|Albian]] ages) Dzunbain Formation of Mongolia. The genus contains a [[Biology:Monotypic taxon|single species]], '''''Mongolostegus exspectabilis''''', known from a fragmentary single specimen representing the first stegosaur named from Mongolia. It is one of the youngest known stegosaurs, along with ''[[Biology:Yanbeilong|Yanbeilong]]'' and an unnamed species from the [[Earth:Hekou Group|Hekou Group]] of China. In contrast to these taxa, which are members of the late-diverging stegosaur subfamily Stegosaurinae, ''Mongolostegus'' may have affinities to more [[Biology:Basal (phylogenetics)|basal]] taxa such as the Huayangosauridae. | |||
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==Discovery and description== | |||
[[File:Mongolostegus exspectabilis.png|thumb|left|Speculative [[life restoration]] as a stegosaurid]] | |||
''Mongolostegus | The ''Mongolostegus'' [[Biology:Holotype|holotype]] specimen, PIN 3779-15 was discovered in 1981 by a joint expedition between Soviet and Mongolian researchers. The specimen, recovered from a layer of the Dzunbain Formation at Chamrin-Us, Mongolia, comprises a single caudosacral vertebra articulated with the first five {{dinogloss|caudals|caudal vertebrae}}, a {{dinogloss|sacrum|sacral rib}}, the left {{dinogloss|pubis}} and part of the right pubis, and various pelvic bone fragments.<ref name="Mongolostegus">{{Cite journal |last1=Tumanova |first1=T. A. |last2=Alifanov |first2=V. R. |date=December 2018 |title=First Record of Stegosaur (Ornithischia, Dinosauria) from the Aptian–Albian of Mongolia |journal=Paleontological Journal |language=en |volume=52 |issue=14 |pages=1771–1779 |doi=10.1134/S0031030118140186 |issn=0031-0301}}</ref> | ||
''Mongolostegus'' was first reported by Alifanov et al. (2005) and Alifanov (2012) as an indeterminate stegosaur.<ref>Alifanov, B.P., Tumanova, T.A. & Kurzanov, C.M. (2005): [First discovery of a stegosaur in Mongolia]. – Priroda, 12: 61-63. (In Russian).</ref><ref>Alifanov, B.P. (2012): [Fossil Vertebrates of Russia and Adjacent Countries. Fossil Reptiles and Birds. Part 2]; Moscow (GEOS). (In Russian).</ref> In 2014, Ulansky informally dubbed the material ''Wuerhosaurus'' "mongoliensis,<ref name="ulansky14">Ulansky, Roman. E., (2014). Evolution of the stegosaurs (Dinosauria; Ornithischia). ''Dinologia'', 35 pp. [in Russian]. [http://dinoweb.narod.ru/Ulansky_2014_Stegosaurs_evolution.pdf PDF].</ref> but Galton and Carpenter (2016) noted the invalid status of this name as a ''[[Biology:Nomen nudum|nomen nudum]]''.<ref>Galton, Peter M.; Carpenter, Kenneth M (2016). "The plated dinosaur ''Stegosaurus longispinus'' Gilmore, 1914 (Dinosauria: Ornithischia; Upper Jurassic, western USA), type species of ''Alcovasaurus'' n. gen". ''Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen''. 279 (2): 185–208. doi:10.1127/njgpa/2016/0551.</ref> | |||
''Mongolostegus'' | In 2018, Tumanova and Alifanov formally [[Biology:Species description|described]] ''Mongolostegus exspectabilis'' as a new genus and species of stegosaurs based on these remains. The [[Biology:Genus|generic name]], ''Mongolostegus'', combines a reference to the discovery of the specimen in Mongolia with the [[Social:Greek language|Greek]] ''stege'', meaning "roof". The [[Biology:Specific name (zoology)|specific name]], ''exspectabilis'', is derived from a [[Social:Latin|Latin]] word meaning "expected for a long time". ''Mongolostegus'' is the first and only stegosaur named from this country.<ref name="Mongolostegus" /> | ||
Dating to the end of the [[Earth:Early Cretaceous|Early Cretaceous]], ''Mongolostegus'' is notably one of the few known Cretaceous stegosaurs and one of the youngest (most recent) known members of this clade in the fossil record.<ref name="Mongolostegus" /> ''[[Biology:Yanbeilong|Yanbeilong]]'' from the Zuoyun Formation and an unnamed species from the Hekou Group, both from China, date to similar ages.<ref name="Yanbeilong">{{Cite journal |last1=Jia |first1=Lei |last2=Li |first2=Ning |last3=Dong |first3=Liyang |last4=Shi |first4=Jianru |last5=Kang |first5=Zhishuai |last6=Wang |first6=Suozhu |last7=Xu |first7=Shichao |last8=You |first8=Hailu |date=2024-01-31 |title=A new stegosaur from the late Early Cretaceous of Zuoyun, Shanxi Province, China |journal=[[Biology:Historical Biology|Historical Biology]] |volume=37 |issue=2 |language=en |pages=420–429 |doi=10.1080/08912963.2024.2308214 |issn=0891-2963 }}</ref><ref name="Li2024">{{Cite journal |last1=Li |first1=Ning |last2=Li |first2=Daqing |last3=Peng |first3=Guangzhao |last4=You |first4=Hailu |date=2024 |title=The first stegosaurian dinosaur from Gansu Province, China |journal=Cretaceous Research |volume=158 |language=en |pages=105852 |doi=10.1016/j.cretres.2024.105852|bibcode=2024CrRes.15805852L }}</ref><ref name="SF&C25">{{cite journal|last1=Sánchez-Fenollosa |first1=Sergio |last2=Cobos |first2=Alberto |year=2025 |title=New insights into the phylogeny and skull evolution of stegosaurian dinosaurs: An extraordinary cranium from the European Late Jurassic (Dinosauria: Stegosauria) |journal=Vertebrate Zoology |volume=75 |pages=147–171 |doi=10.3897/vz.75.e146618 |doi-access=free}}</ref> | |||
== Classification == | == Classification == | ||
Tumanova and Alifanov (2018) | In their 2018 description of ''Mongolostegus'', Tumanova and Alifanov (2018) described this taxon as a member of the [[Biology:Stegosauridae|Stegosauridae]] without further discussion.<ref name="Mongolostegus" /> The first research to include ''Mongolostegus'' was published in 2025 by Sánchez-Fenollosa & Cobos in a revision of stegosaur phylogeny and nomenclature. The authors noted that the very fragmentary nature of the species' holotype reduced the resolution of their results, requiring them to remove it for optimal clarity. When included, ''Mongolostegus'' was recovered in a [[Biology:Polytomy|polytomy]] with the most early-diverging ([[Biology:Basal (phylogenetics)|basal]]) stegosaurs, including ''Huayangosaurus'', ''[[Biology:Gigantspinosaurus|Gigantspinosaurus]]'', and ''Bashanosaurus'', all known from the Middle–Late Jurassic. This position is supported by anatomical features of the tail vertebrate (the lack of dorsal processes on the {{dinogloss|transverse processes}} and unexpanded apices of the {{dinogloss|neural spines}}) and pubis (postpubis dorsal edge lacking a distinct kink). As such, the authors interpreted ''Mongolostegus'' as a late-surviving member of either the Huayangosauridae or early-diverging Stegosauridae. These results are displayed in the [[Biology:Cladogram|cladogram]] below:<ref name="SF&C25" /> | ||
{{clade | |||
|{{clade | |||
|1=''Bashanosaurus'' <div style="{{MirrorH}}">60px</div> | |||
|2=''Baiyinosaurus'' <div style="{{MirrorH}}">60px</div> | |||
|3=''Chungkingosaurus'' <div style="{{MirrorH}}">60px</div> | |||
|4=''[[Biology:Gigantspinosaurus|Gigantspinosaurus]]'' <div style="{{MirrorH}}">60px</div> | |||
|5=''Huayangosaurus'' <div style="{{MirrorH}}">60px</div> | |||
|6=''[[Biology:Isaberrysaura|Isaberrysaura]]'' <div style="{{MirrorH}}">60px</div> | |||
|7='''''Mongolostegus''''' <div style="{{MirrorH}}">60px</div> | |||
|label8=[[Biology:Stegosauridae|Stegosauridae]] | |||
|8={{clade | |||
|1={{clade | |||
|1=''Tuojiangosaurus'' <div style="{{MirrorH}}">60px</div> | |||
|2=''[[Biology:Paranthodon|Paranthodon]]'' <div style="{{MirrorH}}">60px</div> }} | |||
|label3=Neostegosauria | |||
|3={{clade | |||
|label1=Dacentrurinae | |||
|1={{clade hidden |id=1 | |||
|expand-text=<div style="{{MirrorH}}">68px</div> | |||
|1=''Alcovasaurus'' <div style="{{MirrorH}}">60px</div> | |||
|2={{clade | |||
|1=''[[Biology:Kentrosaurus|Kentrosaurus]]'' <div style="{{MirrorH}}">60px</div> | |||
|2={{clade | |||
|1=''Thyreosaurus'' <div style="{{MirrorH}}">60px</div> | |||
|2={{clade | |||
|1=''Adratiklit'' <div style="{{MirrorH}}">60px</div> | |||
|2=''[[Biology:Dacentrurus|Dacentrurus]]'' <div style="{{MirrorH}}">68px</div><br>{{small|(including ''[[Biology:Miragaia longicollum|Miragaia]]'')}} }} }} }} }} | |||
|label3=Stegosaurinae | |||
|3={{clade hidden |id=2 | |||
|expand-text=<div style="{{MirrorH}}">60px</div> | |||
|1={{clade | |||
|1={{clade | |||
|1=[[Earth:Qigu Formation|Qigu Formation]] stegosaur | |||
|2=''[[Biology:Loricatosaurus|Loricatosaurus]]'' <div style="{{MirrorH}}">60px</div> }} | |||
|3={{clade | |||
|1=''Hesperosaurus'' <div style="{{MirrorH}}">55px</div> | |||
|2=''Stegosaurus stenops'' <div style="{{MirrorH}}">60px</div> }} }} | |||
|3={{clade | |||
|1=''Jiangjunosaurus'' <div style="{{MirrorH}}">60px</div> | |||
|2={{clade | |||
|1=[[Earth:Hekou Group|Hekou Group]] stegosaur | |||
|2={{clade | |||
|1=''Wuerhosaurus homheni'' <div style="{{MirrorH}}">65px</div> | |||
|2=''[[Biology:Yanbeilong|Yanbeilong]]'' <div style="{{MirrorH}}">60px</div> | |||
}} }} }} }} }} }} }}|label1=Stegosauria}} | |||
== See also == | == See also == | ||
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{{Reflist}} | {{Reflist}} | ||
{{Stegosauria|S.}} | |||
{{Taxonbar|from=Q61732137}} | {{Taxonbar|from=Q61732137}} | ||
[[Category: | [[Category:Dinosaur genera]] | ||
{{Sourceattribution|Mongolostegus}} | {{Sourceattribution|Mongolostegus}} | ||
Latest revision as of 23:39, 9 August 2025
Mongolostegus (meaning "Mongolian roof") is an extinct genus of stegosaurian dinosaurs from the Early Cretaceous (Aptian–Albian ages) Dzunbain Formation of Mongolia. The genus contains a single species, Mongolostegus exspectabilis, known from a fragmentary single specimen representing the first stegosaur named from Mongolia. It is one of the youngest known stegosaurs, along with Yanbeilong and an unnamed species from the Hekou Group of China. In contrast to these taxa, which are members of the late-diverging stegosaur subfamily Stegosaurinae, Mongolostegus may have affinities to more basal taxa such as the Huayangosauridae.
Discovery and description
Speculative life restoration as a stegosaurid
The Mongolostegus holotype specimen, PIN 3779-15 was discovered in 1981 by a joint expedition between Soviet and Mongolian researchers. The specimen, recovered from a layer of the Dzunbain Formation at Chamrin-Us, Mongolia, comprises a single caudosacral vertebra articulated with the first five caudal vertebrae, a sacral rib, the left pubis and part of the right pubis, and various pelvic bone fragments.[1]
Mongolostegus was first reported by Alifanov et al. (2005) and Alifanov (2012) as an indeterminate stegosaur.[2][3] In 2014, Ulansky informally dubbed the material Wuerhosaurus "mongoliensis,[4] but Galton and Carpenter (2016) noted the invalid status of this name as a nomen nudum.[5]
In 2018, Tumanova and Alifanov formally described Mongolostegus exspectabilis as a new genus and species of stegosaurs based on these remains. The generic name, Mongolostegus, combines a reference to the discovery of the specimen in Mongolia with the Greek stege, meaning "roof". The specific name, exspectabilis, is derived from a Latin word meaning "expected for a long time". Mongolostegus is the first and only stegosaur named from this country.[1]
Dating to the end of the Early Cretaceous, Mongolostegus is notably one of the few known Cretaceous stegosaurs and one of the youngest (most recent) known members of this clade in the fossil record.[1] Yanbeilong from the Zuoyun Formation and an unnamed species from the Hekou Group, both from China, date to similar ages.[6][7][8]
Classification
In their 2018 description of Mongolostegus, Tumanova and Alifanov (2018) described this taxon as a member of the Stegosauridae without further discussion.[1] The first research to include Mongolostegus was published in 2025 by Sánchez-Fenollosa & Cobos in a revision of stegosaur phylogeny and nomenclature. The authors noted that the very fragmentary nature of the species' holotype reduced the resolution of their results, requiring them to remove it for optimal clarity. When included, Mongolostegus was recovered in a polytomy with the most early-diverging (basal) stegosaurs, including Huayangosaurus, Gigantspinosaurus, and Bashanosaurus, all known from the Middle–Late Jurassic. This position is supported by anatomical features of the tail vertebrate (the lack of dorsal processes on the transverse processes and unexpanded apices of the neural spines) and pubis (postpubis dorsal edge lacking a distinct kink). As such, the authors interpreted Mongolostegus as a late-surviving member of either the Huayangosauridae or early-diverging Stegosauridae. These results are displayed in the cladogram below:[8]
| Stegosauria |
| ||||||||||||||||||||||||||||||||||||||||||
See also
References
- ↑ 1.0 1.1 1.2 1.3 Tumanova, T. A.; Alifanov, V. R. (December 2018). "First Record of Stegosaur (Ornithischia, Dinosauria) from the Aptian–Albian of Mongolia" (in en). Paleontological Journal 52 (14): 1771–1779. doi:10.1134/S0031030118140186. ISSN 0031-0301.
- ↑ Alifanov, B.P., Tumanova, T.A. & Kurzanov, C.M. (2005): [First discovery of a stegosaur in Mongolia]. – Priroda, 12: 61-63. (In Russian).
- ↑ Alifanov, B.P. (2012): [Fossil Vertebrates of Russia and Adjacent Countries. Fossil Reptiles and Birds. Part 2]; Moscow (GEOS). (In Russian).
- ↑ Ulansky, Roman. E., (2014). Evolution of the stegosaurs (Dinosauria; Ornithischia). Dinologia, 35 pp. [in Russian]. PDF.
- ↑ Galton, Peter M.; Carpenter, Kenneth M (2016). "The plated dinosaur Stegosaurus longispinus Gilmore, 1914 (Dinosauria: Ornithischia; Upper Jurassic, western USA), type species of Alcovasaurus n. gen". Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen. 279 (2): 185–208. doi:10.1127/njgpa/2016/0551.
- ↑ Jia, Lei; Li, Ning; Dong, Liyang; Shi, Jianru; Kang, Zhishuai; Wang, Suozhu; Xu, Shichao; You, Hailu (2024-01-31). "A new stegosaur from the late Early Cretaceous of Zuoyun, Shanxi Province, China" (in en). Historical Biology 37 (2): 420–429. doi:10.1080/08912963.2024.2308214. ISSN 0891-2963.
- ↑ Li, Ning; Li, Daqing; Peng, Guangzhao; You, Hailu (2024). "The first stegosaurian dinosaur from Gansu Province, China" (in en). Cretaceous Research 158: 105852. doi:10.1016/j.cretres.2024.105852. Bibcode: 2024CrRes.15805852L.
- ↑ 8.0 8.1 Sánchez-Fenollosa, Sergio; Cobos, Alberto (2025). "New insights into the phylogeny and skull evolution of stegosaurian dinosaurs: An extraordinary cranium from the European Late Jurassic (Dinosauria: Stegosauria)". Vertebrate Zoology 75: 147–171. doi:10.3897/vz.75.e146618.
Template:Stegosauria Wikidata ☰ Q61732137 entry
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