Thunnosauria

From Palaeos.org

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

Painting of the Early Jurassic Thunnosaur Ichthyosaurus by Heinrich Harder.

[edit] Introduction

The Thunnosaurs constitute the representative ichthyosaurs in the mind of the general enthusiast; perfectly streamlined, fish- or dolphin- like Jurassic marine reptiles. The name "Thunnosauria" is a very recent one, it first appears in Motani, 1999 to refer to the most derived clade of ichthyosaurs, those with a tuna-like tailfin.

It will be disappointing if this turns out not to be a clade, since it is so aptly named. These are, indeed, the tuna-lizards.

[edit] Information

Thunnosauria: Chacaicosaurus

Range: Late Triassic, but mostly Early Jurassic to middle Cretaceous

Phylogeny: Parvipelvia: Temnodontosaurus + Eurhinosauria + Thunnosauria: Stenopterygius + (Ichthyosaurus + Ophthalmosauria).

[edit] Characters

Characters: diapophyses & parapophyses round [S97]; diapophysis on anterior spine attaches to neural arch & moves down centrum to fuse with parapophysis in sacral vertebrae [S97]; parapophysis also moves ventrally, but not as much; caudal vertebrae with 1 articular facet [S97]; pubis & ischium rod-like [M97].

References: McGowan (1997) [M97]; Sander (1997) [S97].

[edit] Phylogeny

<==Thunnosauria
   |--Ichthyosaurus De La Beche & Conybeare 1821 (see below for synonymy)
   |    |--*I. communis Conybeare 1822
   |    |--I. acutirostris
   |    |--I. breviceps Owen 1881
   |    |--I. conybeari Lydekker 1888
   |    |--I. intermedius Conybeare 1822
   |    |--‘Protoichthyosaurus’ porostealis Appleby 1979
   |    `--‘*Protoichthyosaurus’ postaxalis Appleby 1979
   `--+--Stenopterygiidae
      |    |--Chacaicosaurus Fernández 1994
      |    |    `--*C. cayi Fernández 1994
      |    `--Stenopterygius Jaekel 1904
      |         |--*S. quadricissus (Quenstedt 1856)
      |         |--S. hauffianus von Huene 1922
      |         |--S. longifrons (Owen 1881)
      |         `--S. megalorhinus von Huene 1922
      `--+--Aegirosaurus Bardet & Fernández 2000
         |    |--*A. leptospondylus (Wagner 1873) [=Ichthyosaurus leptospondylus]
         |    `--‘Ophthalmosaurus’ monocharactus Appleby 1956
         `--Ophthalmosauridae [Ophthalmosauridae]
              |--Brachypterygius von Huene 1922 (see below for synonymy)
              |    |--*B. extremus (Boulenger 1904)
              |    |--B. mordax (McGowan 1976) [=Grendelius mordax]
              |    `--B. pseudoscythius (Efimov 1998) (see below for synonymy)
              |--Platypterygius von Huene 1922 (see below for synonymy)
              |    |--*P. platydactylus (Broili 1907)
              |    |--P. americanus (Nace 1939)
              |    |--P. bannovkensis Arkhangelsky 1998 [=P. (Pervushovisaurus) bannovkensis]
              |    |--P. bedengensis (Efimov 1998) [=*Plutoniosaurus bedengensis]
              |    |--P. birjukovi (Otschev & Efimov 1985) [=*Simbirskiasaurus birjukovi]
              |    |--P. hauthali (von Huene 1926)
              |    |--P. hercynicus Kuhn 1946
              |    |--P. kiprijanoffi Romer 1968
              |    `--P. longmani Wade 1990
              `--+--Caypullisaurus Fernández 1997
                 |    `--*C. bonapartei Fernández 1997
                 `--Ophthalmosaurus Seeley 1874 (see below for synonymy)
                      |--*O. icenicus Seeley 1874
                      |--‘*Khudiakovia’ calloviensis Arkhangelsky 1999 (n. d.)
                      |--O. gorodischensis (Efimov 1999) (see below for synonymy)
                      |--O. natans (Marsh 1879)
                      |--O. periallus (Fernández 1999) [=Mollesaurus periallus]
                      |--‘Paraophthalmosaurus’ saratoviensis
                      |--O. saveljeviensis (Arkhangelsky 1997) (see below for synonymy)
                      `--O. yasykovi (Efimov 1999) (see below for synonymy)

Brachypterygius von Huene 1922 [incl. Grendelius McGowan 1976, Otschevia Efimov 1998]

Brachypterygius pseudoscythius (Efimov 1998) [=*Otschevia pseudoscythia; incl. B. zhuravlevi Arkhangelsky 1998]

Ichthyosaurus De La Beche & Conybeare 1821 [incl. Eurypterygius Jaekel 1904, Protoichthyosaurus Appleby 1979]

Ophthalmosaurus Seeley 1874 [incl. Ancanamunia Rusconi 1942, Apatodontosaurus Mehl 1927, Baptanodon Marsh 1880, Khudiakovia Arkhangelsky 1999, Mollesaurus Fernández 1999, Paraophthalmosaurus Arkhangelsky 1997, Sauranodon Marsh 1879 (preoc.), Undorosaurus Efimov 1999, Yasykovia Efimov 1999]

Ophthalmosaurus gorodischensis (Efimov 1999) [=*Undorosaurus gorodischensis; incl. U. khorlovensis, U. nessovi]

Ophthalmosaurus saveljeviensis (Arkhangelsky 1997) [=*Paraophthalmosaurus saveljeviensis]

Ophthalmosaurus yasykovi (Efimov 1999) [=*Yasykovia yasykovi; incl. Y. kabanovi, Y. mittai, Y. sumini]

Platypterygius von Huene 1922 [incl. Longirostria Arkhangelsky 1998, Myobradypterygius von Huene 1926, Myopterygius von Huene 1922, Pervushovisaurus Arkhangelsky 1998, Plutoniosaurus Efimov 1997, Simbirskiasaurus Ochev & Efimov 1985, Tenuirostria Arkhangelsky 1998]

* Type species of generic name indicated

[edit] References

Maisch, M. W., & A. T. Matzke. 2000. The Ichthyosauria. Stuttgarter Beiträge zur Naturkunde Serie B (Geologie und Paläontologie) 298: 1-159.

Maisch, M. W., & A. T. Matzke. 2003. Observations on Triassic ichthyosaurs. Part XII. A new Early Triassic ichthyosaur genus from Spitzbergen. Neues Jahrbuch für Geologie und Paläontologie – Abhandlungen 229 (3): 317-338.

McGowan, C. 1997. A transitional ichthyosaur fauna. In Ancient Marine Reptiles (J. M. Callaway & E. L. Nicholls, eds.) pp. 61-80. Academic Press.

Norman, D. 1985 (reprinted 2000). The Illustrated Encyclopedia of Dinosaurs. Salamander Books: London.

Sander, P. M. 1997. The paleogeography of Shastasaurus. In Ancient Marine Reptiles (J. M. Callaway & E. L. Nicholls, eds.) pp. 17-43. Academic Press.

[edit] Credits

ATW020517 Palaeos com, MAK070121, phylogeny Christopher 23:07, 17 November 2008 (UTC)