RESEARCH & KNOWLEDGE Research Article Vol. 3 No. 1 page 43-46 DOI: 10.14456/randk.2017.11 * Author for correspondence: Sebastien.Olive@naturalsciences.be. Systematic revision of the Cretaceous actinopterygian fauna from Bernissart, Belgium Sebastien Olive 1, * , Louis Taverne 1 , Lionel Cavin 2 and Uthumporn Deesri 3 1 OD Earth and Life History, Royal Belgian Institute of Natural Sciences, Rue Vautier 29, 1000 Brussels, Belgium. 2 Department of Geology and Palaeontology, Muséum d’Histoire Naturelle, CP6434, 1211 Geneva 6, Switzerland 3 Department of Earth- and Environmental Sciences, Palaeontology & Geobiology, and GeoBio-Center, Ludwig-Maximilians-University (Received 5 May 2017; accepted 14 June 2017) Abstract - The Cretaceous locality of Bernissart, Belgium, is well known for the Iguanodon remains it yielded. Fossils were collected during coalmine exploitation at the end of the 19th century. In the frame of the ColdCase project, which aims to understand the ecological and geological conditions in the Bernissart lake/swamp during the Barremian, a revision of the actinopterygian fauna from Bernissart, found alongside Iguanodons, has been launched. The revision of the ichtyofauna has started with taxa, unstudied since 1911: Coccolepis macroptera, Lepidotus bernissartensis, L. brevifulcratus and L. arcuatus. The study shows that the material attributed to both genera could likely be attributed to other genera and that the reduced actinopterygian taxic diversity found at Bernissart conirms the lacustrine to swampy environment Keywords: Barremian, Belgium, Bernissart, Coccolepis, Lepidotes 1. Introduction The Cretaceous locality of Bernissart, Belgium, is well known for the Iguanodon remains it yielded. Fossils were collected during coalmine exploitation. Godefroit et al. (2012) documented the historical background of this discovery. Although this fossil locality has been the subject of numerous scientiic papers and monographies since its discovery 136 years ago, the processes leading to the local accumulation of so many complete skeletons remain completely unexplained. This is partly due to the lack of integrative studies taking care of associated faunas and loras, geology, taphonomy, sedimentology and micropal- eontology. In this context, the ColdCase project, funded by the Belgian government, saw the light of day. This project is clue to understand the evolution of the ecological and geological conditions in the Bernissart lake/swamp during the Barremian, which led to such an accumulation of Iguanodon skeletons. In the frame of this project, the revision of the actinopterygian fauna from Bernissart has been launched. Alongside the dinosaur remains, about 3,000 actinopterygian specimens were also unearthed. These actinopterygians were studied by Traquair (1911), who recognized 16 species belonging to 11 genera. Further studies by Gaudant (1966), Taverne (1981; 1982; 1999), Grande and Bemis (1998) and Poyato-Ariza and Wenz (2004) modiied the initial systematic and nomenclatural composition of the assemblage. We have started the revision of the ichtyofauna with taxa, unstudied since Traquair (1911): Coccolepis macroptera, Lepidotus bernissartensis, L. brevifulcratus and L. arcuatus. 2. “Coccolepis” Coccolepidids are basal (i.e. non –neopterygian) actinop- terygians, whose diversity was mainly due to the specious variety of the genus Coccolepis. However, this diversity has considerably decreased after recent morphological studies . Coccolepis groeberi became Condorlepis groeberi (López-Arbarello et al., 2013). C. aniscowitchi, C. socialis, C. cockerelli and C. martynovi were referred to Morrolepis aniscowitchi, and Coccolepis andrewsi became Morrolepis andrewsi according to Skrzycka (2014). Coccolepis bucklandi, the type species of the genus Coccolepis, was quite recently reviewed (Hilton et al., 2004) and C. liassica, C. australis, C. yumenensis and C. woodwardi are in need of revision. Reciprocally, the number of genera within the family Coccolepididae has increased. “Coccolepis” macroptera, from Bernissart (Fig. 1), is another example of a taxon with uncertain generic and speciic situation.