Topic
Contectopalatus
About: Contectopalatus is a research topic. Over the lifetime, 3 publications have been published within this topic receiving 47 citations.
Papers
TL;DR: The supratemporal, squamosal, and quadratojugal are all present in Mixosaurus atavus, as in basal ichthyopterygians, and should be considered derived if it is not preservational.
Abstract: Mixosaurus, a Middle Triassic ichthyopterygian, has traditionally been recognized as a typically primitive ichthyopterygian, but this view was recently questioned. Examination of the skull of Mixosaurus revealed many features to confirm this doubt. Its cranial characters, such as the parietal ridge and short supratemporal process of the parietal, are shared with derived ichthyopterygians from the Jurassic. Mixosaurus also has features that are derived within the Ichthyopterygia and unique to the genus, such as a long sagittal crest reaching the nasal, and an expanded anterior terrace of the upper temporal fenestra that also reaches the nasal. Phalarodon, Contectopalatus, and Sangiorgiosaurus are all considered as junior synonyms of Mixosaurus. The supratemporal, squamosal, and quadratojugal are all present in Mixosaurus atavus, as in basal ichthyopterygians. Because all basal ichthyopterygians, and even some derived ichthyopterygians from the Jurassic, have these three elements, the absence of the squamosal in Ichthyosaurus and Platypterygius should be considered derived if it is not preservational.
30 citations
TL;DR: A new partial skull of the Middle Triassic ichthyosaur Contectopalatus atavus allows many new osteological observations and makes the referral of several additional specimens, including lower jaw material, possible, which aids very much in the understanding of the anatomy of this highly derived mixosaurid species.
Abstract: A new partial skull of the Middle Triassic ichthyosaur Contectopalatus atavus allows many new osteological observations and makes the referral of several additional specimens, including lower jaw material, possible. This aids very much in the understanding of the anatomy of this highly derived mixosaurid species. The lectotype of Ichthyosaurus atavus is shown to be diagnostic and the recent proposal of a neotype is unnecessary. Contectopalatus shows thecodont dentition in all parts of the jaws. The teeth are labyrinthodont at their bases. Some specimens, which are interpreted as very late ontogenetic stages of C. atavus, indicate that Contectopalatus grew very large, reaching four to five times the size of other mixosaurids. Mixosaurid taxonomy is reviewed. Three valid genera can be included in a monophyletic Mixosauridae: Mixosaurus (including M. cornalianus and M. kuhnschnyderi), PhalarodonContectopalatus (monotypic). The mixosaurids are the sister group to the remaining ichthyosaurs, apart from the Lower Triassic forms. The status of the Omphalosauridae remains unresolved, but they are not closely related to the mixosaurids, because the durophagous dentition was acquired convergently in the two groups.
16 citations
TL;DR: Mixosaurs were a highly specialized, uniquely adapted and very diverse ichthyosaur family, some members of which rank among the marine top predators of their time.
Abstract: The skull of the mixosaurid species Contectopalatus atavus (Quenstedt, 1851–52) is the most bizarre of any known ichthyosaur. It possesses a very high sagittal crest formed by the nasal, frontal and parietal bones which grows higher during ontogeny. This skull structure - found to a lesser extent in the other mixosaurid genera Mixosaurus and Phalarodon - is a synapomorphy of the family Mixosauridae. It is here interpreted as correlated with a unique arrangement of the jaw adductor musculature among tetrapods, with the internal jaw adductors extending over most of the skull roof up to the external narial opening. This reconstruction would increase the biting force considerably and the hypothesis is supported by peculiarities of the dentition and jaws of Contectopalatus. Contectopalatus probably reached a length of about 5 meters. It is therefore the largest known mixosaurid and one of the largest Triassic ichthyosaurs. The general text-book picture of mixosaurs as small, rather unspecialized, primitive ichthyosaurs is incorrect. Mixosaurs were a highly specialized, uniquely adapted and very diverse ichthyosaur family, some members of which rank among the marine top predators of their time.
12 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2001 | 1 |
| 2000 | 1 |
| 1999 | 1 |