PBDB Taxon

Basic info	Taxonomic history	Classification	Included Taxa
Morphology	Ecology and taphonomy	External Literature Search	Age range and collections

Thalattosauriformes

Reptilia

Taxonomy

Thalattosauriformes was named by Nicholls (1999). It was considered monophyletic by Nicholls (1999).

It was assigned to Diapsida by Nicholls (1999); and to Diapsida by Müller (2005), Müller (2007).

Subtaxa

Thalattosauria

Sister taxa

Thalattosauria

Synonymy list

Year	Name and author
1999	Thalattosauriformes Nicholls p. 25
2005	Thalattosauriformes Müller
2007	Thalattosauriformes Müller p. 236

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Rank	Name	Author
kingdom	Animalia	()
—	Bilateria
—	Eubilateria	Ax 1987
—	Deuterostomia
phylum	Chordata	Haeckel 1874
subphylum	Vertebrata
superclass	Gnathostomata
—	Osteichthyes	()
subclass	Sarcopterygii	()
subclass	Dipnotetrapodomorpha	(Nelson 2006)
subclass	Tetrapodomorpha	()
—	Tetrapoda

Rank	Name	Author
—	Reptiliomorpha
—	Anthracosauria
subclass	Amphibiosauria	Kuhn 1967
—	Cotylosauria	()
—	Amniota
—	Sauropsida
class	Reptilia
subclass	Eureptilia	()
—	Romeriida
—	Diapsida	()
—	Thalattosauriformes
—	Thalattosauriformes

If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.

Unr. †Thalattosauriformes Nicholls 1999

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Or. †Thalattosauria Merriam 1905

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Superfm. †Askeptosauroidea Wu et al. 2009

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Fm. †Askeptosauridae

G. †Anshunsaurus Liu 1999

†Anshunsaurus huangguoshuensis Liu 1999

†Anshunsaurus huangnihensis Cheng et al. 2007

†Anshunsaurus wushaensis Rieppel et al. 2006

G. †Askeptosaurus Nopcsa 1925

†Askeptosaurus italicus Nopsca 1925

G. †Miodentosaurus Cheng et al. 2007

†Miodentosaurus brevis Cheng et al. 2007

G. †Endennasaurus Renesto 1984

†Endennasaurus acutirostris Renesto 1984

Superfm. †Thalattosauroidea Nopcsa 1928

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G. †Agkistrognathus Nicholls and Brinkman 1993

†Agkistrognathus campbelli Nicholls and Brinkman 1993

G. †Clarazia Peyer 1936

†Clarazia schinzi Peyer 1936

G. †Gunakadeit Druckenmiller et al. 2020

†Gunakadeit joseeae Druckenmiller et al. 2020

G. †Hescheleria Peyer 1936

†Hescheleria rubeli Peyer 1936

G. †Nectosaurus Merriam 1905

†Nectosaurus halius Merriam 1905

G. †Paralonectes Nicholls and Brinkman 1993

†Paralonectes merriami Nicholls and Brinkman 1993

Fm. †Thalattosauridae Merriam 1904

G. †Concavispina Zhao et al. 2013

†Concavispina biseridens Zhao et al. 2013

Invalid names: Thalattosaurida Nicholls 1999 [empty]

G. †Thalattosaurus Merriam 1904

†Thalattosaurus alexandrae Merriam 1904

†Thalattosaurus borealis Nicholls and Brinkman 1993

Invalid names: Thalattosaurus perrini Merriam 1905 [nomen dubium], Thalattosaurus shastensis Merriam 1905 [nomen dubium]

G. †Xinpusaurus Yin 2000

†Xinpusaurus bamaolinensis Cheng 2003

†Xinpusaurus kohi Jiang et al. 2004

†Xinpusaurus suni Yin 2000

†Xinpusaurus xingyiensis Li et al. 2016

Diagnosis

Reference	Diagnosis
E. L. Nicholls 1999	It is diagnosed by the following four unequivocal synapomorphies —[17] premaxilla elongated into rostrum; [24] elongate retroarticular process; [36] caudal vertebrae distinctive, with high, posteriorly inclined neural spines; [39] ilium with narrow, posteriorly angled iliac blade. Other characters, which probably diagnose this clade cannot be considered equivocal due to incomplete preser- vation of Endennosaurus. These include [ 1 ] supratcmporal fenestra small and narrow; [3] supratemporal bone lies deep, along lateral surface of parietal; [4] skull emarginated posteriorly, with occiput anterior to mandibular articulation.