-The present work is a taxonomical study of the continental mollusks collected in several fossil outcrops in the districts of Biberach and Ravensburg (SE Baden-Württemberg state) and Neu-Ulm (SW Bavaria state), Germany, by one of the authors (V.J.S.) in the years 1983-2013. All these fossil sites are of Middle Miocene age (European Mammal Neogene zones MN 5 and MN 6) and belong to the Upper Freshwater Molasse ("Obere Süßwassermolasse" or OSM), in the North Alpine Foreland Basin of southern Germany. The molluscan fauna of these sites counts with 17 gastropod and three bivalve species: Tinnyea laureae, Pomatias sp., Bithynia sp., Theodoxus sp., Galba cf. 202REVISTA BRASILEIRA DE PALEONTOLOGIA, 18(2), 2015 MATERIAL AND METHODSThe mollusk-bearing fossil sites in the districts of Biberach, Ravensburg and Neu-Ulm can be seen in Figure 1, as named by Sach (1999. The Middle Miocene fossil sites studied here are detailed below. Lattentobel: 47º49'49.70'', N 9º25'57.63''E; fine-sand horizons with reworked OSM components, ~610 m; Mammal Neogene zone MN 6. 10º06'39.93''E; fi nesand horizons with reworked OSM components, ~562-566 m a.s.l.; additional fi ne-sand horizon with bivalves (Margaritifera fl abellata) at ~570 m a.s.l.; Mammal Neogene zone MN 5. Biberach District Neu-Ulm District
Herein, we revise an extensive set of mollusc fossils from the Upper Freshwater Molasse deposits of Öhningen palaeolake (SW Germany; Middle Miocene, MN7). Based on material housed in paleontological collections in Europe and North America, we present the first thorough systematic account of the phylum from this historic locality. A total of ten species were identified from Öhningen: three freshwater gastropods (Lymnaea dilatata Noulet, 1854, Gyraulus cf. applanatus (Thomä), Planorbarius mantelli (Dunker)), two terrestrial gastropods (Granaria cf. schuebleri (Klein), Palaeotachea sylvestrina (Schlotheim)), and five bivalves (Anodonta splendens Goldfuss, A. lavateri (Münster), Pseudunio flabellatus (Goldfuss), “Dreissena” sp., Pisidium escheri (Mayer-Eymar, 1865)). Three freshwater and five terrestrial gastropod genera mentioned in older literature could not be found in the available material. Ours is the first report of a Dreissenidae from Öhningen
Guyanella clenchi (Altena, 1968) is newly reported from Abrolhos Bank, northeastern Brazil. The new records extend the distribution of this species to the Southern Atlantic and reinforce the known overlap between the Caribbean and South American marine faunas. Even though it inhabits well-sampled regions, G. clenchi is a poorly known species which is not well represented in collections. The new occurrence of the species in the Southern Atlantic draws attention to the necessity of further improvement in sampling strategies aimed at filling in the distribution gaps of species.
Members of the small bivalve family Cyrenoididae inhabit brackish waters of the eastern and western Atlantic Ocean. Cyrenoida floridana (Dall, 1896) from the western Atlantic is poorly known aside from shell descriptions. A detailed shell and anatomical study of C. floridana is here presented and compared with available data for Cyrenidae and Glauconomidae, two families of closest relationship according to recent phylogenetic studies. The species is characterized by valves externally covered by thin light brown periostracum; muscle scars and pallial line (without sinus) weakly impressed on the internal shell surface; a unique hinge pattern composed of cardinal and lateral teeth joining each other, right hinge with two laterals and two cardinals forming two inverted-V-shaped teeth and left hinge with two cardinals and one lateral forming a horizontal reversed F-shaped tooth; and microtubules inside the shell walls. Anatomically, the species presents unequal adductor muscles; demibranchs fused to each other along their posterior ends; a pair of totally fused, pigmented siphons; two pairs of siphonal retractor muscles; and a stomach with conjoined style sac and intestine, a single typhlosole, and three sorting areas. Evidence of shell parasitism is described.
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