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Merriamosauria
Taxonomy
Merriamosauria was named by Motani (1999). It is not extant. It was considered monophyletic by Motani (1999).
It was assigned to Cymbospondylidae by Maisch and Matzke (2000); to Merriamosauriformes by McGowan and Motani (2003); to Longipinnati by Maisch et al. (2006) and Maisch (2010); to Hueneosauria by Ji et al. (2016), Moon (2017) and Moon (2019); and to Ichthyosauria by Motani (1999) and Lomax et al. (2024).
It was assigned to Cymbospondylidae by Maisch and Matzke (2000); to Merriamosauriformes by McGowan and Motani (2003); to Longipinnati by Maisch et al. (2006) and Maisch (2010); to Hueneosauria by Ji et al. (2016), Moon (2017) and Moon (2019); and to Ichthyosauria by Motani (1999) and Lomax et al. (2024).
Subtaxa
Synonymy list
| Year | Name and author |
|---|---|
| 1999 | Merriamosauria Motani fig. 1 |
| 2000 | Merriamosauria Maisch and Matzke p. 96 |
| 2003 | Merriamosauria McGowan and Motani |
| 2006 | Merriamosauria Maisch et al. |
| 2010 | Merriamosauria Maisch |
| 2016 | Merriamosauria Ji et al. p. 10 |
| 2017 | Merriamosauria Moon |
| 2019 | Merriamosauria Moon p. 145 |
| 2024 | Merriamosauria Lomax et al. p. 8 |
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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. †Merriamosauria Motani 1999
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Fm. †Besanosauridae McGowan and Motani 2003
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Fm. †Californosauridae Von Huene 1948
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Fm. †Guanlingsauridae Yin et al. 2000
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Fm. †Shastasauridae Merriam 1902
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G. †Guizhouichthyosaurus Cao and Luo 2000
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†Guizhouichthyosaurus tangae Cao et al. 2000
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Invalid names: Cymbospondylus asiaticus Li and You 2002 [synonym], Panjiangsaurus epicharis Chen and Cheng 2003 [synonym]
†Guizhouichthyosaurus wolonggangense Chen et al. 2007
G. †Shastasaurus Merriam 1895
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†Shastasaurus alexandrae Merriam 1902
†Shastasaurus careyi Merriam 1902
†Shastasaurus pacificus Merriam 1895
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Invalid names: Shastasaurus altispinus Merriam 1902 [synonym], Shastasaurus osmonti Merriam 1902 [synonym]
†Shastasaurus sikkaniensis Nicholls and Manabe 2004
Invalid names: Shastasaurus carinthiacus von Huene 1925 [nomen dubium], Shastasaurus merriami von Huene 1916 [nomen dubium], Shastasaurus nordensis Ochev 1972 [nomen dubium]
G. †Shonisaurus Camp 1976
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†Shonisaurus popularis Camp 1976
Invalid names: Shonisaurus mulleri Camp 1976 [nomen dubium], Shonisaurus silberlingi Camp 1976 [nomen dubium]
Invalid names: Ichthyosaurus carinatus Sauvage 1876 [nomen dubium], Ichthyosaurus rheticus Sauvage 1876 [nomen dubium], Shastasaurinae Merriam 1908 [empty], Shastasaurus sieversi Riabinin 1946 [nomen dubium]
Fm. †Shonisauridae Camp 1980
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Invalid names: Euichthyosauria Motani 1999 [empty], Shastasauria Motani 1999 [empty]
Diagnosis
| Reference | Diagnosis | |
|---|---|---|
| C. Ji et al. 2016 | Postfrontal medial extension over the anterior mar- gin of the upper temporal fenestra; quadratojugal taller than long; scapula anterior process absent, anterior margin slightly convex or nearly straight; coracoid facet on scapula equal to or smaller than glenoid facet; coracoid foramen absent; coracoid concave anteri- orly and posteriorly; humerus distal and proximal width nearly equal; radius peripheral shaft reduced or absent; metacarpal I not ossified; metacarpal III shaft absent; manual digit II distal ele- ments peripheral shaft notched or absent; pes digit I absent; proxi- mal manual phalanges widely spaced along the proximodistal axis; shape of the posterior surface of the ulna rounded; notching of the anterior facet of leading elements of forefin in adult. | |
| B. C. Moon 2019 | The last common ancestor of Shastasaurus pacificus and Ichthyosaurus communis, and all its descendants [node-based] (Motani 1999c). |