HIERARCHICAL CLASSIFICATION OF THE CLASS EODIAPSIDA+

HIERARCHICAL CLASSIFICATION OF THE CLASS EODIAPSIDA+[i]

EUKARYA> UNIKONTA> OPISTHOKONTA> ANIMALIA> BILATERIA> DEUTEROSTOMATA> VERTEBRATA> GNATHOSTOMATA> TETRAPODA> AMNIOTA> EODIAPSIDA

CLASS EODIAPSIDA LINKS

Description of Class

The following descriptions come from Benton (2005). The structure of the following system is also based, in part, on the phylogenetic treatment by Mikko’s Phylogeny Web (from the Finnish Museum of Natural History). Taxa in red are extinct.

CLASS EODIAPSIDA[i] (THE STEM DIAPSIDS)

The first diapsids appeared in the Pennsylvanian and the ichthyosaurs disappeared in the Cretaceous.

SUBCLASS YOUNGINOMORPHA+
- ORDER ARAEOSCELIDIA
- Variable. Some were aquatic and other terrestrial. They had two temporal fenestrae and a suborbital fenestra that penetrated the palate. The teeth were small, sharp, and indicate that it was an insectivore.
- Upper Carboniferous (Pennsylvanian)
- Spinoaequalis, Petrolacosaurus
- ORDER UNNAMED
  - FAMILY WEIGELTISAURIDAE
  - Very unusual gliding animals. They had elongate ribs that could be folded back when running.
  - Late Permian
  - Coelourosauravus
- ORDER YOUNGINIFORMES
- This group was successful in the upper Permian and lower Triassic. They were lizard-like carnivores and insectivores. Later forms developed the deep tail and paddle-like feet of semi-aquatic reptiles.
- Upper Permian to lower Triassic
  - FAMILY YOUNGINIDAE
  - Youngina, Petrolacosaurus

SUBCLASS ICHTHYOSAUROMORPHA (INCERTAE SEDIS)+
The ichthyosaurs were dolphin-like animals that appeared in the middle Triassic, flourished in the Jurassic, and disappeared in the upper Cretaceous.
- BASAL FAMILY
- FAMILY HUPEHSUCHIDAE
- Hupehsuchus.
SUPERORDER ICHTHYOPTERYGIA
- FAMILY UTATSUSAURIDAE
- Thaisaurus, Isfjordosaurus, Parvinatator.
SUPERORDER EOICHTHYOSAURIA
- FAMILY GRIPPIDAE
- Grippia, Chaohusaurus.
- ORDER ICHTHYOSAURIA
- UNASSIGNED GENERA
- Mikadocephalus, Shastasaurus, Wimanius, Cymbospondylus.
  - SUBORDER MIXOSAURIA
    - FAMILY MIXOSAURIDAE
    - Phalarodon, Mixosaurus.
  - SUBORDER MERRIAMOSAURIFORMES
    - BASAL FAMILIES
    - FAMILY GUANLINGSAURIDAE
    - Guanlingsaurus
    - FAMILY BESANOSAURIDAE
    - Besanosaurus
    - FAMILY MERRIAMOSAURIDAE
    - Merriamosaurus.
  - INFRAORDER SHASTASAURIA
    - FAMILY SHASTASAURIDAE
    - Pessosaurus, Pessopteryx, Besanosaurus, Himalayasaurus, Shastasaurus, Callawayia, Shonisaurus.
  - INFRAORDER EUICHTHYOSAURIA
    - FAMILY TORETOCNEMIDAE
    - Qianichthyosaurus, Toretocnemus.
    - FAMILY CALIFORNOSAURIDAE
    - Californosaurus.
  - INFRAORDER PARVIPELIA
    - FAMILY MACGOVANIDAE
    - Macgovania
    - FAMILY HUDSONELPIDIDAE
    - Hudsonelpidia.
    - FAMILY SUEVOLEVIATHANIDAE
    - Suevoleviathan
    - FAMILY EURHINOSAURIDAE (=LEPTONECTIDAE)
    - Leptonectes, Eurhinosaurus.
    - FAMILY TEMNODONTOSAURIDAE
    - Temnodontosaurus
  - INFRAORDER THUNNOSAURIA
  - Ichthyosaurs that had a tuna-like caudal fin.
    - FAMILY STENOPTERYGIIDAE
    - Chacaicosaurus, Mollesaurus, Stenopterygius.
    - FAMILY ICHTHYOSAURIDAE
    - Ichthyosaurus.
    - INFRAORDER OPHTHALMOSAURIA
    - FAMILY OPHTHALMOSAURIDAE
    - Aegirosaurus, Nannopterygius, Simbirskiasaurus, Paraophthalmosaurus, Otschevia, Plutoniosaurus, Undorosaurus, Brachypterygius, Ophthalmosaurus, Caypullisaurus, Platypterygius.

[i] I created this term to refer to the stem diapsids. The name literally means dawn diapsids.

LITERATURE CITED

Benton, M. J. 2005. Vertebrate Paleontology. Third Edition. Blackwell Publishing, Malden, MA.

deBraga, M. and R. R. Reisz. 1995. A new diapsid reptile from the uppermost Carboniferous (Stephanian) of Kansas. Palaeontology. 38: 199-212.

Falcon-Lang, H. J., M. J. Benton, and M. Stimson. 2007. Ecology of early reptiles inferred from Lower Pennsylvanian trackways. Journal of the Geological Society, London. 164(6): 1113-1118.

Laurin, M. and J. A. Gauthier. 2000. Diapsida. In: Maddison, D. R., ed. The Tree of Life Web Project. [http://tolweb.org/tree?group=Diapsida&contgroup=Amniota

Lingham-Soliar, T. 1999. A functional analysis of the skull of Goronyosaurus nigeriensis (Squamata: Mosasauridae) and its bearing on the predatory behavior and evolution of the enigmatic taxon. N. Jb. Geol. Palaeont. Abh. 2134 (3): 355-74.

Martill D. M. 1993. Soupy Substrates: A Medium for the Exceptional Preservation of Ichthyosaurs of the Posidonia Shale (Lower Jurassic) of Germany. Kaupia – Darmstädter Beiträge zur Naturgeschichte. 2: 77-97.

Motani, R. 1997. Temporal and spatial distribution of tooth implantation in ichthyosaurs. In: J. M. Callaway and E. L. Nicholls, eds. Ancient Marine Reptiles. Academic Press. pp. 81–103.

Motani, R., N. Minoura, and T. Ando. 1998. Ichthyosaurian relationships illuminated by new primitive skeletons from Japan. Nature. 393: 255-257.

Motani, R. 2000. Is Omphalosaurus ichthyopterygian? –A phylogenetic perspective. Journal of Vertebrate Paleontology 20:295-301.

Nicholls, E. L. and M. Manabe. 2001. A new genus of ichthyosaur from the Late Triassic Pardonet Formation of British Columbia: bridging the Triassic-Jurassic gap. Canadian Journal of Earth Sciences. 38: 983-1002.

By Jack R. Holt. Last revised: 01/20/2013

HIERARCHICAL CLASSIFICATION OF THE CLASS EODIAPSIDA+[i]

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