Topic
Eosuchus
About: Eosuchus is a research topic. Over the lifetime, 3 publications have been published within this topic receiving 112 citations.
Papers
TL;DR: Eosuchus minor is a slender-snouted form and can be distinguished from most other crocodylians on the basis of an enlarged quadrate foramen aereum; a distinct W-shaped rugosity along the ventral margin of the basioccipital tuber; and arrangement of dentary alveoli into couplets.
Abstract: Eosuchus minor (Marsh, 1870) is based on skeletal fragments from the Late Paleocene or Early Eocene of New Jersey, but more complete material from the Late Paleocene of New Jersey, Maryland, and Virginia permits a detailed description and systematic assessment. It is a slender-snouted form and can be distinguished from most other crocodylians on the basis of an enlarged quadrate foramen aereum; a distinct W-shaped rugosity along the ventral margin of the basioccipital tuber; a prominent crest on the lateral braincase wall encompassing portions of the quadrate, pterygoid, and basisphenoid, forming the lateral wall of the lateral eustachian canal at its ventralmost extent; and arrangement of dentary alveoli into couplets. Specimens of larger crocodylians from the same units may represent either the adult form of E. minor or a separate taxon. The enlarged quadrate foramen aereum, couplet arrangement of dentary alveoli, and basioccipital tuber shape are shared with Eosuchus lerichei from the Late Paleocene of Europe. Eosuchus lies within Gavialoidea crownward of the basal forms Thoracosaurus and Eothoracosaurus. The braincase of Eosuchus is intermediate between that of Thoracosaurus and that of Gavialis; the basisphenoid retains a short (but externally visible) descending lamina, but the basisphenoid is also anteroposteriorly expanded at the level of the median eustachian foramen.
61 citations
Journal Article•
TL;DR: The results of the cladistic analysis show that the European spe− cies possess characters that can be considered as slightly derived if compared to those of its American relative, suggesting an eastward dispersion from North America before the Paleocene–Eocene boundary and before the full opening of the At− lantic Ocean or local evolution from a basal gavialoid stock similar to E. minor.
Abstract: Originally designated by Dollo in 1907, the holotype of Eosuchus lerichei has never been carefully described but simply cited and compared in a number of papers. This work is an attempt to fill this gap and to place this taxon in a cladistic phylogenetic context. E. lerichei can be considered a valid basal gavialoid from late Paleocene of North Western Europe, sharing the presence of extremely enlarged foramina aerea on quadrates with the coeval Eosuchus minor from eastern North America (formerly described as Gavialis minor). These two species can be considered sister taxa and, for priority reason, they should be both ascribed to genus Eosuchus. The results of the cladistic analysis show that the European spe− cies possess characters that can be considered as slightly derived if compared to those of its American relative, suggesting an eastward dispersion from North America before the Paleocene–Eocene boundary and before the full opening of the At− lantic Ocean or local evolution from a basal gavialoid stock similar to E. minor. Both species of Eosuchus come from ma− rine outcrops and represent a further evidence for the salt−water tolerance of the earliest stages of Gavialoidea evolution− ary history. Despite the present endemicity of the only living gharial, Gavialis gangeticus, the historical biogeography of gavialoids shows a lost global distribution and reveals several transoceanic dispersals.
52 citations
TL;DR: A partial skull from the early Eocene London Clay of the Isle of Sheppey, England, is referable to the gavialoid clade Eosuchus, otherwise known from the late Paleocene of continental Europe and North America.
Abstract: A partial skull from the early Eocene London Clay of the Isle of Sheppey, England, is referable to the gavialoid clade Eosuchus, otherwise known from the late Paleocene of continental Europe and North America. It differs slightly from Paleocene forms, but there is insufficient material on which to base a new species. This extends the range of Eosuchus beyond the Paleocene and represents the first unambiguous occurrence of a gavialoid in the early Eocene.
13 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2006 | 2 |
| 2005 | 1 |