Syngonosaurus

Syngonosaurus; Temporal range: late Albian; ~105–100 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
	Vertebra of S. macrocercus as seen from two different angles
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Clade:	†Ornithischia
Clade:	†Neornithischia
Clade:	†Ornithopoda
Clade:	†Iguanodontia
Genus:	†Syngonosaurus; Seeley, 1879
Species:	†S. macrocercus
Binomial name
	†Syngonosaurus macrocercus; Seeley, 1879
Synonyms
	Acanthopholis macrocercus Seeley, 1869; Anoplosaurus macrocercus Kuhn, 1964; Sygmosaurus (sic); Sygnosaurus (sic);

Syngonosaurus is an extinct genus of ornithopod dinosaur from the Early Cretaceous. It was an iguanodontian discovered in the Cambridge Greensand of England^[1] and was first described in 1879. The type species, S. macrocercus, was described by British paleontologist Harry Seeley in 1879^[2] and it was later synonymised with Acanthopholis, but the genus was reinstated in a 2020 study, when Syngonosaurus and Eucercosaurus were reinterpreted as basal iguanodontians.^[3]

Discovery and naming[edit]

In 1869 Harry Govier Seeley named several new species of Acanthopholis based on remains from the Cambridge Greensand, including A. macrocercus, based on specimens CAMSM B55570-55609.^[4]

In 1879 Seeley named the genus Syngonosaurus based on part of the type material of Acanthopholis macrocercus.^[2]

In 1999 Xabier Pereda-Superbiola and Paul M. Barrett reviewed all Acanthopholis material. They concluded that all species were nomina dubia whose syntype specimens were composites of non-diagnostic ankylosaur and ornithopod remains; including Syngonosaurus.^[5]

Syngonosaurus was synonymised with Acanthopholis in 1999, but the genus was reinstated in a 2020 study, when Syngonosaurus and Eucercosaurus were reinterpreted as basal iguanodontians.^[3]

Classification[edit]

Syngonosaurus was seen as an ankylosaur in both a 2001 publication^[1] and a 2004 publication.^[6] In 2020, Syngonosaurus was classified into Iguanodontia.^[3]

References[edit]

^ ^a ^b Carpenter, Kenneth (2001). "Phylogenetic Analysis of Ankylosauria". In Carpenter, Kenneth (ed.). The Armored Dinosaurs. Indiana University Press. pp. 455–480. ISBN 0-253-33964-2.
^ ^a ^b ^c Seeley, H.G. (1879). "On the Dinosauria of the Cambridge Greensand". Quarterly Journal of the Geological Society. 35 (1–4): 591–636. doi:10.1144/GSL.JGS.1879.035.01-04.42. ISSN 0370-291X. S2CID 129277596.
^ ^a ^b ^c Barrett, Paul M.; Bonsor, Joseph A. (2020). "A revision of the non-avian dinosaurs Eucercosaurus tanyspondylus and Syngonosaurus macrocercus from the Cambridge Greensand, UK". Cretaceous Research. 118: 104638. doi:10.1016/j.cretres.2020.104638. S2CID 225289654.
^ Seeley, H.G. (1871). "XXXVII.— On Acanthopholis platypus (Seeley), a Pachypod from the Cambridge Upper Greensand". Annals and Magazine of Natural History. 8 (47): 305–318. doi:10.1080/00222937108696494. ISSN 0374-5481.
^ Superbiola, X.P.; Barrett, P.M. (1999). "A systematic review of ankylosaurian dinosaur remains from the Albian-Cenomanian of England". Special Papers in Palaeontology. 60: 177–208.
^ M. K. Vickaryous, T. Maryanska, and D. B. Weishampel. 2004. Ankylosauria. In D. B. Weishampel, P. Dodson, and H. Osmolska (eds.), The Dinosauria (second edition). University of California Press, Berkeley 363-392

[Carpenter2001-1] Carpenter, Kenneth (2001). "Phylogenetic Analysis of Ankylosauria". In Carpenter, Kenneth (ed.). The Armored Dinosaurs. Indiana University Press. pp. 455–480. ISBN 0-253-33964-2.

[Seeley1879-2] Seeley, H.G. (1879). "On the Dinosauria of the Cambridge Greensand". Quarterly Journal of the Geological Society. 35 (1–4): 591–636. doi:10.1144/GSL.JGS.1879.035.01-04.42. ISSN 0370-291X. S2CID 129277596.

[Barrett2020-3] Barrett, Paul M.; Bonsor, Joseph A. (2020). "A revision of the non-avian dinosaurs Eucercosaurus tanyspondylus and Syngonosaurus macrocercus from the Cambridge Greensand, UK". Cretaceous Research. 118: 104638. doi:10.1016/j.cretres.2020.104638. S2CID 225289654.

[4] Seeley, H.G. (1871). "XXXVII.— On Acanthopholis platypus (Seeley), a Pachypod from the Cambridge Upper Greensand". Annals and Magazine of Natural History. 8 (47): 305–318. doi:10.1080/00222937108696494. ISSN 0374-5481.

[5] Superbiola, X.P.; Barrett, P.M. (1999). "A systematic review of ankylosaurian dinosaur remains from the Albian-Cenomanian of England". Special Papers in Palaeontology. 60: 177–208.

[6] M. K. Vickaryous, T. Maryanska, and D. B. Weishampel. 2004. Ankylosauria. In D. B. Weishampel, P. Dodson, and H. Osmolska (eds.), The Dinosauria (second edition). University of California Press, Berkeley 363-392

[1]