title: A 365-Million-Year-Old Freshwater Community Reveals Morphological and Ecological Stasis in Branchiopod Crustaceans.
abstract: Branchiopod crustaceans are represented by fairy, tadpole, and clam shrimps (Anostraca, Notostraca, Laevicaudata, Spinicaudata), which typically inhabit temporary freshwater bodies, and water fleas (Cladoceromorpha), which live in all kinds of freshwater and occasionally marine environments [1, 2]. The earliest branchiopods occur in the Cambrian, where they are represented by complete body fossils from Sweden such as Rehbachiella kinnekullensis [3] and isolated mandibles preserved as small carbonaceous fossils [4-6] from Canada. The earliest known continental branchiopods are associated with hot spring environments [7] represented by the Early Devonian Rhynie Chert of Scotland (410 million years ago) and include possible stem-group or crown-group Anostraca, Notostraca, and clam shrimps or Cladoceromorpha [8-10], which differ morphologically from their modern counterparts [1, 2, 11]. Here we report the discovery of an ephemeral pool branchiopod community from the 365-million-year-old Strud locality of Belgium. It is characterized by new anostracans and spinicaudatans, closely resembling extant species, and the earliest notostracan, Strudops goldenbergi [12]. These branchiopods released resting eggs into the sediment in a manner similar to their modern representatives [1, 2]. We infer that this reproductive strategy was critical to overcoming environmental constraints such as seasonal desiccation imposed by living on land. The pioneer colonization of ephemeral freshwater pools by branchiopods in the Devonian was followed by remarkable ecological and morphological stasis that persists to the present day.
authors.affiliation: Centre de Recherche sur la Paléobiodiversité et les Paléoenvironnements (CR2P, UMR 7207), Sorbonne Universités, MNHN, CNRS, UPMC-Paris6; Muséum national d'Histoire naturelle, 57 rue Cuvier, CP 38, 75005 Paris, France; IPANEMA, CNRS, ministère de la Culture et de la Communication, USR3461, Université Paris-Saclay, 91192 Gif-sur-Yvette, France; Synchrotron SOLEIL, BP 48 Saint-Aubin, 91192 Gif-sur-Yvette, France. Electronic address: gueriau@mnhn.fr.
authors.forename: Pierre
authors.initials: P
authors.lastname: Gueriau
authors.affiliation: Unité Biologie des Organismes et Écosystèmes Aquatiques (BOREA, UMR 7208), Sorbonne Universités, MNHN, UPMC-Paris6, UCBN, CNRS, IRD; Muséum national d'Histoire naturelle, 57 rue Cuvier, CP 26, 75005 Paris, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Rabet
authors.affiliation: Centre de Recherche sur la Paléobiodiversité et les Paléoenvironnements (CR2P, UMR 7207), Sorbonne Universités, MNHN, CNRS, UPMC-Paris6; Muséum national d'Histoire naturelle, 57 rue Cuvier, CP 38, 75005 Paris, France.
authors.forename: Gaël
authors.initials: G
authors.lastname: Clément
authors.affiliation: Department of Earth Sciences, Uppsala University, Villavägen 16, 752 36 Uppsala, Sweden.
authors.forename: Linda
authors.initials: L
authors.lastname: Lagebro
authors.affiliation: UMR 5276 CNRS, Laboratoire de Géologie de Lyon, Terre, Planètes, Environnement (LGLTPE), Géode, campus LyonTech-la Doua, Université Lyon 1, 2 rue Dubois, 69622 Villeurbanne, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Vannier
authors.affiliation: Department of Geology and Geophysics and Yale Peabody Museum of Natural History, Yale University, PO Box 208109, New Haven, CT 06520-8109, USA.
authors.forename: Derek E G
authors.initials: DE
authors.lastname: Briggs
authors.affiliation: Centre de Recherche sur la Paléobiodiversité et les Paléoenvironnements (CR2P, UMR 7207), Sorbonne Universités, MNHN, CNRS, UPMC-Paris6; Muséum national d'Histoire naturelle, 57 rue Cuvier, CP 38, 75005 Paris, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Charbonnier
authors.affiliation: Royal Belgian Institute of Natural Sciences, Directorate Earth and History of Life, Palaeobiosphere and Evolution, Rue Vautier 29, 1000 Brussels, Belgium; Liège University, Geology Department, Evolution and Diversity Dynamics Lab, B18, Allée du Six-Août, 4000 Liège, Belgium.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Olive
authors.affiliation: Centre de Recherche sur la Paléobiodiversité et les Paléoenvironnements (CR2P, UMR 7207), Sorbonne Universités, MNHN, CNRS, UPMC-Paris6; Muséum national d'Histoire naturelle, 57 rue Cuvier, CP 38, 75005 Paris, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Béthoux
mesh_terms: D000818:Animals; D001530:Belgium; D003445:Crustacea / Q000033:anatomy & histology* / Q000145:classification / Q000502:physiology*; D005580:Fossils / Q000033:anatomy & histology*; D005618:Fresh Water