Spiraloconulus suprajurassicus n. sp. - a New Benthic Foraminifer from the Late Jurassic of the Northern Calcareous Alps of Austria

摘要

A new large-sized foraminifer is described as Spiraloconulus suprajurassicus n. sp. from the Kimmeridgian-Tithonian of the Northern Calcareous Alps of Austria. A further occurrence is from the Late Tithonian-Early Berriasian of Romania. It represents the third species of the genus Spiraloconulus Allemann & Schroeder, 1980 known so far from the interval Late Aalenian-Bathonian (Early Callovian?). Given its ammobaculitoid morphology, its coarsely agglutinated habitus and the preference for well-agitated external platform settings, S. suprajurassicus can be compared with S. giganteus Cherchi & Schroeder. A Middle-Late Jurassic phylogenetic lineage from S. perconigi to S. giganteus and finally S. suprajurassicus is postulated attended by an increase of complexity of the marginal zone. Spiraloconulus suprajurassicus represents a rare foraminifer in the Late Jurassic of the Northern Calcareous Alps, mostly occurring in resediments, e.g., the Barmstein Limestone.