Merriamosauria

From Palaeos.org

Latest revision as of 08:17, 21 February 2012

o Ichthyopterygia
`--o ICHTHYOSAURIA
   |--Cymbospondylus
   `--+--Mixosaurus 
      `--o--Guanlingsaurus
         `--o Merriamosauria
            |--Shastasauridae
            `--o Euichthyosauria 
               |--Teretocnemidae
               `--+--Californosaurus
                  `--o Parvipelvia 
                     }--Macgovania
                     `--+--Hudsonelpidia
                        `--+--Suevoleviathan
                           `--+--Temnodontosaurus
                              |--Leptonectidae
                              `--o Thunnosauria 
                                 |--Stenopterygius
                                 |--Ichthyosaurus
                                 `--Ophthalmosauria

Introduction

The clade Merriamosauria includes all the ichthyosaurs apart from some early but successful primitive Triassic forms like Mixosaurus and Cymbospondylus

There are two main subgroups, the wholely Triassic Shastasauridae and the Late Triassic to Cretaceous Euichthyosauria. The Shastasauridae are sometimes considered paraphyletic grade, and sometimes a parallel clade, to the Euichthyosauria.

Information

Range: Middle Triassic to Late Cretaceous. Mostly Late Triassic and Jurassic forms.

Phylogeny: Ichthyosauria:: Mixosaurus + *: Shastasauria + Euichthyosauria.

Characters

Characters: tooth implantation aulacodont except in Shonisaurus (Shastasauria), which has unique implantation like Cymbospondylus [M97]; tooth roots not expanded [M97].

References: Motani (1997) [M97].

References

• Motani, R. (1997), Temporal and spatial distribution of tooth implantation in ichthyosaurs, in JM Callaway & EL Nicholls (eds.), Ancient Marine Reptiles. Academic Press. pp. 81-103.

Links

• Eyes

Credits

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