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2 2025

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Crinoids (Echinodermata, Articulata) from the Campanian (Upper Cretaceous) rocky shore at Ivö Klack, southern Sweden

Gale Andrew Scott, Stevenson Angela

Acta Geologica Polonica

2025

Vol. 75, no. 2

art. no. e45

Ten species of crinoids are recorded from a rocky shoreline deposit of upper lower Campanian age at Ivö Klack in southern Sweden. These include three comatulids, i.e., Semiometra annulata Rasmussen, 1961, S. impressa (Carpenter, 1881), and Loriolometra retzii (Lundgren, 1875), three isocrinids, i.e., Nielsenicrinus cf. carinatus (Roemer, 1840), and isocrinid sp. 1 and sp. 2, as well as four pelagic roveacrinids, i.e., Stellacrinus lineatus Gale, 2018, Crassicoma suedica sp. nov., Applinocrinus cretaceus forma spinifer Gale, 2018 and Cultellacrinus labyrinthus Gale, 2016. The comatulids and isocrinids coexisted in shallow (<30 m), high energy coastal environments, whereas the roveacrinids were Chalk Sea dwellers in the upper water column that were washed into the shallows by currents. The presence of isocrinids in such shallow habitats is remarkable given that these environments are characterised by high biodiversity, intense predation pressure, strong currents and wave agitated waters – conditions typically considered unsuitable for these slow moving stalked crinoids, and the reason they are thought to be confined to depths in excess of 100 m in present day oceans. The Ivö Klack specimens presented herein represent the only known occurrence of isocrinids in a rocky shoreline deposit, marking a notable shift in isocrinid ecology and habitat association. The limited stratigraphical ranges of the roveacrinids in expanded chalk successions elsewhere corroborates other age assignments of the succession at Ivö Klack.

Asteroids (Echinodermata) from the Campanian (Upper Cretaceous) rocky shore at Ivö Klack, southern Sweden

Gale Andrew Scott

Acta Geologica Polonica

2025

Vol. 75, no. 2

art. no. e47

The asteroid fauna from the upper lower Campanian rocky coastline at Ivö Klack is described, and its palaeoecology is discussed in comparison with other Cretaceous and present-day shallow-marine assemblages. Twentysix taxa are recorded, belonging predominantly to the Goniasteridae (11 species), with smaller representatives of the families Podosphaerasteridae (4 taxa), Astropectinidae (3 taxa), Forcipulatida (2 taxa), Pterasteridae, Korethrasteridae, Pseudarchasteridae, Pycinasteridae, Asterinidae, and Stauranderasteridae (all one species each). Five new genera are described (Scaniasterina, type species S. surlyki sp. nov.; Granulasterias, type species G. ivoensis sp. nov.; Rugametopaster, type species Metopaster rugissimus Gale, 1987a; Ivoaster, type species I. soerensenae sp. nov. and Vectisaster, type species V. enigmaticus sp. nov.). In addition, new species erected include Astropecten erectus sp. nov., Manfredaster graveseni sp. nov., Metopaster asgaardae sp. nov., Nymphaster macrogranularis sp. nov., N. minigranularis sp. nov., Pycinaster christenseni sp. nov. and Remaster cretaceus sp. nov. Metopaster tamarae Gale, 1987a, is transferred to the genus Weitschataster Neumann and Girod, 2018. The asteroid fauna shows marked similarities to a Cenomanian–Turonian assemblage from rocky shorelines in the Bohemian Basin, Czech Republic, but differs in important respects from present-day shallow-marine asteroid assemblages from around the world.