New information on the cranial anatomy of the eel genus Echelus Rafinesque, 1810 (Ophichthidae: Anguilliformes) from the Early Eocene
Sally V. T. Young, R. J. Williams, 2008. "New information on the cranial anatomy of the eel genus Echelus Rafinesque, 1810 (Ophichthidae: Anguilliformes) from the Early Eocene", Fishes and the Break-up of Pangaea, L. Cavin, A. Longbottom, M. Richter
Download citation file:
Two neurocrania of the eel genus Echelus Rafinesque, 1810 were collected from the London Clay Formation, Eocene, from Aveley, Essex. They are identified herein as E. branchialis Woodward, 1901. One specimen retains an incomplete premaxillary ethmo vomerine plate, normally lost in fossil specimens, and provides further anatomical information and taxonomic characters for this species.
The geographical range of the species is extended and localities of fossil species of Echelus and other fossil taxa believed by various authors to be closely-related to Echelus species are depicted on a map of the distribution of continental crust in the northern hemisphere during Oligocene times. The distribution of such eel taxa is consistent with the supposed extent of the Eocene sea within Europe. It would appear that modern species of Echelus now occupy areas that are more cosmopolitan than the fossil species. During the break-up of Pangaea and the subsequent expansion of the Atlantic and Indo-Pacific Oceans species of Echelus have ventured beyond their original provenance of continental sea and now occupy habitats along margins of the eastern Atlantic and of the western and eastern Indo-Pacific Oceans.
Figures & Tables
This volume, in honour of Peter L. Forey, is about fishes as palaeobiogeographic indicators in the Mesozoic and Cenozoic. The last 250 million years in the history of Earth have witnessed the break-up of Pangaea, affecting the biogeography of organisms. Fishes occupy almost all freshwater and marine environments, making them a good tool to assess palaeogeographic models.
The volume begins with studies of Triassic chondrichthyans and lungfishes, with reflections on Triassic palaeogeography. Phylogeny and distribution of Late Jurassic neoselachians and basal teleosts are broached, and are followed by five papers about the Cretaceous, dealing with SE Asian sharks, South American ray-finned fishes and coelacanths, European characiforms, and global fish palaeogeography. Then six papers cover Tertiary subjects, such as bony tongues, eels, cypriniforms and coelacanths.
There is generally a good fit between fish phylogenies and the evolution of the palaeogeographical pattern, although a few discrepancies question details of current palaeogeographic models and/or some aspects of fish phylogeny.