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Showing results for tags 'perissodactyl'.
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From the album: TEETH & JAWS
Lophiodon is a middle to large sized herbivore that occurred in Europe during the middle and upper Eocene. One of the latest species, the Bartonian Lophiodon lautricense from Robiac (Gard, France), reached the body size of a horse or a small rhino. Lophiodontidae are basal Perissodactyla, and were regarded as closely related to Tapiroidea within Ceratomorpha due to the similarities in the lophodont dentition (Cuvier 1822, Radinsky 1963, McKenna & Bell 1997). hooker (1984, 2005) and hooker and Dashzeveg (2004) discussed a closer relationship with chalicotheriids within Ancylopoda. This relationship was accepted by Froehlich (1999), Rose and Archibald (2005), and Rose (2006). Holbrook (2009) investigated cranial, postcranial, and dental characters and concluded that Lophiodontidae are best classified as a sister taxon in Ceratomorpha (Tapiroidea plus Rhinocerotoidea), and thus that Lophiodon is closer to Tapiroidea than to Chalicotheriidae. Several species were described for the genus Lophiodon that differ mainly in size, but the variability within the species is very great. The molarization of the premolars is used for taxonomic purposes. In the maxilla there are six postcanines (three premolars and three molars) separated from the anterior dentition by a short diastema. Credit Wighart von Koenigswald • Ann. ZOOL. Fennici Vol. 51, for this description. Order PERISSODACTYLA Suborder CERATOMORPHA Family LOPHIODONTIDAE Lophiodon lautricense NOULET, 1892 Late Middle Eocene (Bartonian) Robiac, Gard Dept., France (This image is best viewed by clicking on the button on the upper right of this page => "other sizes" => "large".)© Harry Pristis 2014 (image)
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I live in Florida, the place of abundant Neogene (Miocene, Pliocene, Pleistocene) mammal fossils. We just don't have much in the way of Paleogene (Oligocene, Eocene, Paleocene) land mammal fossils in the Southeastern U.S. I hadn't given Paleogene fossils much attention beyond a handful of fossils from the Badlands in Northcentral states. That is, until I acquired some examples of Late Eocene perissodactyls from Europe. Here's what I discovered: Plagiolophus (and sister taxa) are palaeotheres, a successful and variable family of perissodactyls (horses, rhinos, tapirs, et. al.) in the Eocene of Western Europe. Not true horses, palaeotheres may be the ancestors of horses. Plagiolophus represents one genus of palaeothere, extinct since the Oligocene. Plagiolophus minor, a browser, was the only member of its family to survive more than fleetingly the mammalian faunal turnover, the "Grande Coupure," which occurred during the earliest Oligocene in Europe. La Debruge is one of about 15 terrestrial faunas (fossil remains of all kinds: plants, aquatic and terrestrial invertebrates, microfossils, vertebrates, mammal footprints) in the Apt-Forcalquier-Manosque basin in the French Alps. (Apt is a small town and is an administrative center of the Vaucluse district.) It is a mostly-paleogene basin with no outflow that accumulated siliciclastic alluvial sediments along with carlcareous deposits in fluctuating shallow lakes. The Paleogene of the basin starts in the Late Eocene with a coastal plain to supratidal flat environment temporarily covered by salt lakes or flood plains and progresses further to a truly closed lacustrine drainage basin towards the Early Oligocene. The Oligocene broadly saw the development of a fluctuating fluvial/lake-system with calcareous, clay and siliciclastic deposits. Many mammals and other vertebrate fossil remains are known from this period all over the region. The Neogene (Miocene) saw a return to marine conditions with the Burdigalian transgression, leaving large thicknesses of sediments from erosion of the rising Alp Mountains. The Late Eocene of the basin is known worldwide for the "La Débruge" mammal fauna serving as a reference locality to the European biochronological timescale. The La Debruge reference level zone is Priabonian (37.2 - 33.9 Ma). The La Débruge fauna slightly precedes the Grande Coupure event which saw a renewal of worldwide faunas at the Eocene-Oligocene boundary. The very abundant fossils of the La Débruge fauna were found in an organic-rich deposit indicating a pond-like environment. The sediments are blackish and slightly sandy marls. Contrary to an earlier report, the fossiliferous level contains no lignite. The fossiliferous layer is about 50 cm (~20 inches) thick. Since 1987, the basin has been protected as the Parc Naturel du Luberon. For more info on the Grande Coupure see http://en.wikipedia.org/wiki/Eocene%E2%80%93Oligocene_extinction_event Who here has some Eocene land mammal fossils from anywhere to show us!?
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