The Middle and Late Eocene Lizard faunas of Europe are relatively well known, thanks to a number of lagerstätten (deposits with exceptional preservation) such as the Messel Shale of Germany. However, the Lizards of the Early Eocene are much less well understood, due to a paucity of such sites. This is unfortunate, as this interval starts with the Palaeocene-Eocene Thermal Maximum at 56 million years ago, the which saw the warmest temperatures of the past 66 million years, with Northern Europe developing a sub-tropical to tropical climate, and therefore presumably being a particularly good environment for Lizards.
One exception to this lack of Early Eocene is the Dormaal locality at Zoutleeuw, eastern Belgium, where a fluvial deposit comprised of layers of clayey and lignitic (coal-rich) sands are interbedded with lenses of grey clays. These deposits are thought to have been laid down in a system of rivers and lagoons in the earliest Eocene, and have yielded a diverse fauna of Mammals, Lizards, Fish, Turtles, and Crocodiles.
In a paper published in the journal Royal Society Open Science on 29 June 2022, Andrej Čerňanský of the Department of Ecology at Comenius University in Bratislava, Juan Daza of the Department of Biological Sciences at Sam Houston State University, Richard Smith of the Directorate Earth and History of Life at the Royal Belgian Institute of Natural Sciences, Aaron Bauer of the Department of Biology and Center for Biodiversity and Ecosystem Stewardship at Villanova University, Thierry Smith, also of the Directorate Earth and History of Life at the Royal Belgian Institute of Natural Sciences, and Annelise Folie of the Scientific Survey of Heritage at the Royal Belgian Institute of Natural Sciences, describe A new species of Gacko from the Dormaal Site.
The new species is named Dollogekko dormaalensis, where 'Dollogekko' honours the prominent Belgian palaeontologist Louis Dollo (1857-1931), combined with '-gekko' the Malay root word of the English 'gecko', often used as a suffix for generic names within the group, and 'dormaalensis' means 'from Dormaal'. The species is described from a single incomplete frontal bone (the bone that forms the forehead in Humans).
The frontal bones of Geckos tend to be highly distinctive at the species level, making it possible to reliably describe new taxa on these bones alone. The specimen from which Dollogekko dormaalensis is described comprises about the anterior half of the frontal bone, with the posterior half being lost. The preserved portion is 4.3 mm in length, is tubular-to-funnel-shaped (the whole bone would almost certainly have been hourglass shaped), and would have extended about ¾ of the way around the orbit.
In addition to the partial frontal from which Dollogekko dormaalensis is described, Čerňanský et al. also describe two fragments of dentary and a partial mandible from the same deposit. The dentary fragments appear to be from a Gecko about the same size as Dollogekko dormaalensis, while the partial mandible appears to come from an Animal about twice the size. Since the frontal bone from which Dollogekko dormaalensis is described is fully fused, and therefore presumed to come from an adult individual which has stopped growing, this appears likely to represent a separate species. The dentary fragments are of a size compatible with he frontal bone, but it is impossible to confirm that they belong to the same species, derive from a juvenile of the species which produced the mandible, or represent a third species. Due to this uncertainty, and the low value of mandible fragments for taxonomic purposes, none of these specimens are named, but instead referred to as Gekkota indet 1 (dentaries) and Gekkota indet 2 (mandible).
See also...
Online courses in Palaeontology.
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