Bernard Landau

New Cancellariidae (Mollusca, Gastropoda) from the Miocene Gatun Formation of Panama, with Eleven New Species

Abstract Thirty species of Cancellariidae in 11 genera from the Miocene Gatun Formation in the Panama Canal area, Caribbean Panama, are discussed including two species not represented by specimens suitable for formal description. The following 11 species are described as new: Cancellaria harzhauseri n. sp., Cancellaria mixta n. sp., Bivetiella dilatata n. sp., Euclia alacertata n. sp., Pyruclia tweedledum n. sp., Pyruclia tweedledee n. sp., Massyla toulai n. sp., Aphera aphrodite n. sp., Axelella cativa n. sp., Agatrix agathe n. sp., Ventrilia coatesi n. sp. This assemblage of cancellariids is very diverse and highly endemic, with 18 (60 percent) species found only in the Miocene Gatun Formation. These assemblages all lie within the Gatunian Neogene Paciphile Molluscan Unit 1 (GNPMU1).

Biogeography of Iberian Atlantic Neogene Marginelliform Gastropods (Marginellidae, Cystiscidae): Global Change and Transatlantic Colonization

Abstract The Marginellidae Fleming and the Cystiscidae Stimpson, herein collectively referred to as marginelliform gastropods, are convergent families of thermophilic marine gastropods. Shallow-water marginelliform gastropods are found in the Ibero-Moroccan Gulf and Mediterranean, diversity rapidly increasing towards tropical West Africa. Surprisingly, in the tropical and subtropical European Miocene fossil record, marginelliform genera of tropical affinity such as Persicula Schumacher and Prunum Herrmannsen, occurring today in West Africa, are altogether missing. Others, such as Marginella Lamarck, are present only in the southwestern Iberian and Mediterranean Neogene record. This work describes the marginelliform gastropods from the Atlantic Iberian Neogene. Ten species are recorded, of which three are new, Persicula mikhailovae n. sp., Gibberula costae n. sp., and Gibberula brebioni n. sp. This study shows that Gibberula Swainson and Volvarina Hinds have been present in Europe since the Eocene. Marginella may have originated in southern Africa and migrated north to Europe in the Miocene, never extending further north than west central Portugal. Persicula and Prunum probably originated in the Caribbean and migrated east during the Pliocene, following closure of the Central American Seaway. The colonization of the Pliocene European Atlantic coast by gastropods of these genera was selective, only where high sea-water temperature and high productivity were combined. These findings suggest that post-Messinian recolonization of the Mediterranean during the Pliocene was a complex process, involving colonization by groups originating in various regions of the Atlantic, including Europe, Africa and the Americas.

The Genus Strombus (Mollusca: Caenogastropoda: Strombidae) in the Neogene of the Bocas del Toro Area, Panama, with the Description of Three New Species

Abstract In contrast to the immense effort that has been put into the geological survey and stratigraphic study of the Neogene of Bocas del Toro region (Panama), little research has been done on the systematics of this regions rich gastropod assemblages. This is the first paper dealing primarily with the Bocas Neogene gastropod assemblages (Strombidae) since the pioneer work of Olsson (1922). Neogene strombid assemblages of the Dominican Republic have recently been reviewed and updated, and, therefore, the Strombidae are a suitable starting point for the revision of the gastropod assemblages from the Neogene of Bocas del Toro. Six species of Strombus are described, three of them new: S. acanthospira n. sp., S. pugiloides, S. gatunensis, S. elegantissimus n. sp., S. vermeiji n. sp. and S. cf. floridanus.

The Family Cancellariidae (Mollusca: Gastropoda) in the Neogene of the Bocas Del Toro Region, Panama, with the Description of Seven New Species

Abstract Twenty four species of Cancellariidae belonging to eleven genera occurring in the Neogene Bocas del Toro assemblages, Caribbean Panama, are discussed and figured. The following seven species are described as new: Cancellaria pilula n. sp., Cancellaria isabelae n. sp., Cancellaria stri n. sp., Cancellaria axelolssoni n. sp., Massyla corpulenta n. sp., Aphera trophis n. sp., Admetula valientensis n. sp. The cancellarid genus Charcolleria Olsson, 1942 is considered a synonym of Massyla H. Adams and A. Adams, 1854. Of the 24 species present in the Bocas del Toro, 12 are known also to occur elsewhere in the tropical American Neogene. This level of endemism is high, but not as high as that reported from other Tropical American Neogene assemblages, probably due to the very central geographic location within the Gatunian Province of the Bocas assemblages.

First record of buccinid genus Chauvetia (Mollusca: Gastropoda) from the fossil record of the New World (Miocene, Venezuela) and its paleobiogeographic implications

Abstract Until now, the buccinid genus Chauvetia was considered of European or West African origin, and is still endemic to these areas today. This paper describes the oldest representative of the genus, Chauvetia inopinata nov. sp., from the upper Burdigalian-lower Langhian transition Cantaure Formation of Venezuela. This surprising record suggests a New World tropical origin to the genus and subsequent immigration to the Old World before the earliest known Old World record, which is upper Tortonian. We postulate that this pre-late Tortonian (pre-8.12–7.42 Ma) dispersal of the tropical Gatunian west-Atlantic Chauvetia into the tropical East Atlantic European-West African Province most probably happened during the 10.71–9.36 Ma interval (early—mid Tortonian) during which the Circum-Tropical Current weakened, and the northward Intra-Caribbean Current had started, enhancing the Gulf Stream and the North Atlantic Current. This new data constitutes compelling evidence of a pre-Pliocene eastward dispersal of New World shallow marine organisms across the Atlantic.

Lectotype designation for Murex nebula Montagu 1803 (Mangeliidae) and its implications for Bela Leach in Gray 1847

Bela Leach in Gray is a misapplied and broadly defined genus within the family Mangeliidae Fischer, 1883. Examination of material from the Montagu collection at the Royal Albert Memorial Museum & Art Gallery (RAMM) in Exeter (UK) led to the discovery of six specimens of Murex nebula Montagu 1803 (the type species of Bela). This material is considered to belong to the original lot used by Montagu to define his species. We selected the best-preserved specimen as a lectotype. The lectotype and paralectotypes deposited at the RAMM are fully described and illustrated. Furthermore, diagnostic characters for recognizing B. nebula specimens are presented: protoconch shows weak ornamentation; teleoconch is fusiform with slightly convex whorls characterized by broad, suture-to-suture ribs and dense but weak spiral elements; outer lip is thin; anal sinus is shallow, placed on the shoulder ramp. These key features are of basic importance for: i) restricting the usage of the genus Bela and promoting its stability and consistent usage in literature and ii) separating two allied (and sometimes interchanged) genera: Bela and Mangelia Risso 1826.

Middle and late Badenian palaeoenvironments in the northern Vienna Basin and their potential link to the Badenian Salinity Crisis

Abstract Hydrocarbon exploration in the Bernhardsthal and Bernhardsthal-Sued oil fields documents an up to 2000 m thick succession of middle and upper Badenian deposits in this part of the northern Vienna Basin (Austria). Based on palaeontological analyses of core-samples, well-log data and seismic surveys we propose an integrated stratigraphy and describe the depositional environments. As the middle/late Badenian boundary is correlated with the Langhian/Serravallian boundary, the cores capture the crucial phase of the Middle Miocene Climate Transition. The middle Badenian starts with a major transgression leading to outer neritic to upper bathyal conditions in the northern Vienna Basin, indicated by Bathysiphon-assemblages and glass-sponges. A strong palaeo-relief and rapid synsedimentary subsidence accentuated sedimentation during this phase. The middle/late Badenian boundary coincides with a major drop of relative sea level by about 200 m, resulting in a rapid shift from deeper marine depositional environments to coastal and freshwater swamps. In coeval marine settings, a more than 100 m thick unit of anhydrite-bearing clay formed. This is the first evidence of evaporite precipitation during the Badenian Salinity Crisis in the Vienna Basin. Shallow lagoonal environments with diverse and fully marine mollusc and fish assemblages were established during the subsequent late Badenian re-flooding. In composition, the mollusc fauna differs considerably from older ones and is characterized by the sudden appearance of species with eastern Paratethyan affinities.

The genus Cittarium (Vetigastropoda: Trochoidea) in the Upper Miocene of the Dominican Republic with the description of a new species

Abstract Today, the marine gastropod genus Cittarium is present only in the West Indies faunas, represented by a single species C. pica, also known from the Pleistocene of Bermuda. Herein Cittarium praepica n. sp. is described from the Upper Miocene Cercado Formation of the Dominican Republic. This is the oldest fossil record for the genus in the eastern Tropical America. The new species is compared to the Pleistocene to Recent Caribbean C. pica and to C. maestratii Lozouet, 2002 of the Upper Oligocene of France. The importance of this new record for the geological history and the biogeography of the genus are discussed.