Baptanodon is an ichthyosaur of the Late Jurassic period (160-156 million years ago), named for its supposed lack of teeth (although teeth of this genus have since been discovered). It had a graceful 3.5 m (11 ft) long dolphin-shaped body, and its jaws were well adapted for catching squid. Major fossil finds of this genus have been recorded in North America. The type species, Sauranodon natans, was originally included under Sauranodon in 1879, but this name was preoccupied.

Discovery and species

Baptanodon is a replacement name for Sauranodon applied to ichthyosaur material in 1879 and was moved to its own genus Baptanodon in 1880 when Sauranodon was found to be preoccupied. Baptanodon was considered a junior synonym of Ophthalmosaurus by Maisch & Matzke (2000). However, cladistic analyses published in the 2010s indicate that Baptanodon is not congeneric with Ophthalmosaurus icenicus.

Classification

The cladogram below follows Fischer et al. 2012.

ThunnosauriaIchthyosaurus Stenopterygius Chacaicosaurus Ophthalmosauridae Arthropterygius * Ophthalmosaurinae Mollesaurus Ophthalmosaurus Baptanodon Acamptonectes Platypterygiinae Brachypterygius Maiaspondylus Aegirosaurus Sveltonectes "Platypterygius" hercynicus Caypullisaurus Athabascasaurus "Platypterygius" australis (=Longirostria)
Ichthyosaurus
Stenopterygius Chacaicosaurus Ophthalmosauridae Arthropterygius * Ophthalmosaurinae Mollesaurus Ophthalmosaurus Baptanodon Acamptonectes Platypterygiinae Brachypterygius Maiaspondylus Aegirosaurus Sveltonectes "Platypterygius" hercynicus Caypullisaurus Athabascasaurus "Platypterygius" australis (=Longirostria)
Stenopterygius
Chacaicosaurus Ophthalmosauridae Arthropterygius * Ophthalmosaurinae Mollesaurus Ophthalmosaurus Baptanodon Acamptonectes Platypterygiinae Brachypterygius Maiaspondylus Aegirosaurus Sveltonectes "Platypterygius" hercynicus Caypullisaurus Athabascasaurus "Platypterygius" australis (=Longirostria)
Chacaicosaurus
OphthalmosauridaeArthropterygius * Ophthalmosaurinae Mollesaurus Ophthalmosaurus Baptanodon Acamptonectes Platypterygiinae Brachypterygius Maiaspondylus Aegirosaurus Sveltonectes "Platypterygius" hercynicus Caypullisaurus Athabascasaurus "Platypterygius" australis (=Longirostria)
Arthropterygius
*Ophthalmosaurinae Mollesaurus Ophthalmosaurus Baptanodon Acamptonectes Platypterygiinae Brachypterygius Maiaspondylus Aegirosaurus Sveltonectes "Platypterygius" hercynicus Caypullisaurus Athabascasaurus "Platypterygius" australis (=Longirostria)
OphthalmosaurinaeMollesaurus Ophthalmosaurus Baptanodon Acamptonectes
Mollesaurus
Ophthalmosaurus Baptanodon Acamptonectes
Ophthalmosaurus
Baptanodon Acamptonectes
Baptanodon
Acamptonectes
PlatypterygiinaeBrachypterygius Maiaspondylus Aegirosaurus Sveltonectes "Platypterygius" hercynicus Caypullisaurus Athabascasaurus "Platypterygius" australis (=Longirostria)
Brachypterygius Maiaspondylus Aegirosaurus Sveltonectes
Brachypterygius
Maiaspondylus Aegirosaurus Sveltonectes
Maiaspondylus
Aegirosaurus Sveltonectes
Aegirosaurus
Sveltonectes
"Platypterygius" hercynicus Caypullisaurus Athabascasaurus "Platypterygius" australis (=Longirostria)
"Platypterygius" hercynicus
Caypullisaurus Athabascasaurus "Platypterygius" australis (=Longirostria)
Caypullisaurus
Athabascasaurus "Platypterygius" australis (=Longirostria)
Athabascasaurus
"Platypterygius" australis (=Longirostria)

Palaeobiology

Fossils of Baptanodon have been found in the Oxfordian-age Sundance Formation of Wyoming, which also has yielded fossils of the cryptoclidids Tatenectes and Pantosaurus, and the pliosaurid Megalneusaurus.

See also