Thunnosauria

Thunnosaurians; Temporal range: Early Jurassic-Late Cretaceous, 199.6–93.5 Ma PreꞒ Ꞓ O S D C P T J K Pg N
	Ichthyosaurus breviceps fossil
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	†Ichthyosauria
Node:	†Neoichthyosauria
Node:	†Thunnosauria; Motani, 1999
Subgroups
	†Ichthyosauridae; †Baracromia †Chacaicosaurus; †Stenopterygiidae; †Ophthalmosauridae; ;

Thunnosauria (Greek for "tuna lizard" - thunnos meaning "tuna" and sauros meaning "lizard") is an extinct clade of parvipelvian ichthyosaurs from the Early Jurassic to the early Late Cretaceous (Hettangian - Cenomanian) of Asia, Australia, Europe, North America, and South America. Named by Ryosuke Motani in 1999, it contains the basal taxa Ichthyosaurus and Stenopterygius and the family Ophthalmosauridae. In thunnosaurs, the fore fin is at least twice as long as the hind fin.[1][2]

Phylogeny

Thunnosauria is a node-based taxon defined in 1999 as "the last common ancestor of Ichthyosaurus communis and Stenopterygius quadriscissus and all of its descendants".[1] The cladogram below follows the topology from a 2010 analysis by Patrick S. Druckenmiller and Erin E. Maxwell.[3]

Thunnosauria

Ichthyosaurus

Stenopterygius

"Ophthalmosaurus" natans

Ophthalmosauridae

	Aegirosaurus

	Ophthalmosaurus

"Platypterygius" hercynicus

"Platypterygius" australis

Platypterygius

	Maiaspondylus

	"Platypterygius" americanus

gollark: It might be more efficient in *yours*, sound, to only bother checking the first two characters of each subthing of user input.

gollark: Also, `c=s[i]` should go above `if s[i]=="i"` and this should be `if c=="i"`, I think.

gollark: If you factor in the size of doing all the indents it might be cheaper to do `s=input()` rather than making a function..

gollark: Just brotlipython it.

gollark: I don't see how this line works though: `if c in"ae":a+=int(c=="a")`. I mean, it doesn't look like it would decrement the accumulator at all.

References

Ryosuke Motani (1999). "Phylogeny of the Ichthyopterygia" (PDF). Journal of Vertebrate Paleontology. 19 (3): 472–495. doi:10.1080/02724634.1999.10011160.CS1 maint: uses authors parameter (link)
Michael W. Maisch and Andreas T. Matzke (2000). "The Ichthyosauria" (PDF). Stuttgarter Beiträge zur Naturkunde: Serie B. 298: 1–159.
Patrick S. Druckenmiller and Erin E. Maxwell (2010). "A new Lower Cretaceous (lower Albian) ichthyosaur genus from the Clearwater Formation, Alberta, Canada". Canadian Journal of Earth Sciences. 47 (8): 1037–1053. doi:10.1139/E10-028.CS1 maint: uses authors parameter (link)

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[Motani-1] Ryosuke Motani (1999). "Phylogeny of the Ichthyopterygia" (PDF). Journal of Vertebrate Paleontology. 19 (3): 472–495. doi:10.1080/02724634.1999.10011160.CS1 maint: uses authors parameter (link)

[MaischandMatzke2000-2] Michael W. Maisch and Andreas T. Matzke (2000). "The Ichthyosauria" (PDF). Stuttgarter Beiträge zur Naturkunde: Serie B. 298: 1–159.

[DM10-3] Patrick S. Druckenmiller and Erin E. Maxwell (2010). "A new Lower Cretaceous (lower Albian) ichthyosaur genus from the Clearwater Formation, Alberta, Canada". Canadian Journal of Earth Sciences. 47 (8): 1037–1053. doi:10.1139/E10-028.CS1 maint: uses authors parameter (link)