28 research outputs found
First record of Rhabdoceras suessi (Ammonoidea, Late Triassic) from the Transylvanian Triassic Series of the Eastern Carpathians (Romania) and a review of its biochronology, paleobiogeography and paleoecology
Abstract
The occurrence of the heteromorphic ammonoid Rhabdoceras suessi Hauer, 1860, is recorded for the first time in the Upper Triassic limestone of the Timon-Ciungi olistolith in the Rarău Syncline, Eastern Carpathians. A single specimen of Rhabdoceras suessi co-occurs with Monotis (Monotis) salinaria that constrains its occurrence here to the Upper Norian (Sevatian 1). It is the only known heteromorphic ammonoid in the Upper Triassic of the Romanian Carpathians. Rhabdoceras suessi is a cosmopolitan species widely recorded in low and mid-paleolatitude faunas. It ranges from the Late Norian to the Rhaetian and is suitable for high-resolution worldwide correlations only when it co-occurs with shorter-ranging choristoceratids, monotid bivalves, or the hydrozoan Heterastridium. Formerly considered as the index fossil for the Upper Norian (Sevatian) Suessi Zone, by the latest 1970s this species lost its key biochronologic status among Late Triassic ammonoids, and it generated a controversy in the 1980s concerning the status of the Rhaetian stage. New stratigraphic data from North America and Europe in the subsequent decades resulted in a revised ammonoid biostratigraphy for the uppermost Triassic, the Rhaetian being reinstalled as the topmost stage in the current standard timescale of the Triassic. The geographic distribution of Rhabdoceras is compiled from published worldwide records, and its paleobiogeography and paleoecology are discussed
Land Snail Fauna of Me Aure Cave (WMD007), Moindou, New Caledonia: Human Introductions and Faunal Change
The land snail fauna excavated from a cave at Me Aure on the central
southwestern coast of New Caledonia represents a period of over 3000 yr, from
before human arrival in the island to the present. The material excavated represents
20 terrestrial species in nine families. The fauna reflects the overall land
snail fauna of New Caledonia in being dominated by small snails in the families
Charopidae and Rhytididae, with large Placostylus species (Bulimulidae) present
and minor representation of other families. Two alien species are present: Allopeas
gracile, probably introduced before European arrival, and Achatina fulica,
introduced in 1972. There are suggestions of change in the composition of the
fauna, perhaps associated with the arrival of Europeans and the replacement
of native by alien vegetation, with Andrefrancia vetula and possibly A. saisseti
declining and Rhytida aulacospira increasing