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The collection of cephalopods from eight sampling horizons within the Olenidsletta Member, Valhallfonna Formation, Floian–Dapingian, from Profilstranda and nearby Profilbekken, Ny Friesland, Spitsbergen, resulted in the detection of 31 species, 20 genera, and 12 families from the Ellesmerocerida, Endocerida, Riocerida, Dissidocerida, Orthocerida, Tarphycerida, and Oncocerida. Of these, five genera (Ethanoceras gen. nov., Hinlopoceras gen. nov., Nyfrieslandoceras gen. nov., Olenidslettoceras gen. nov., Svalbardoceras gen. nov.) and 19 species (Bactroceras fluvii sp. nov., Buttsoceras buldrebreenense sp. nov., Cycloplectoceras hinlopense sp. nov., Cyclostomiceras profilstrandense sp. nov., Deltoceras beluga sp. nov., Eosomichelinoceras borealis sp. nov., Ethanoceras solitudines gen. et sp. nov., Hemichoanella occulta sp. nov., Hinlopoceras tempestatis gen. et sp. nov., H. venti gen. et sp. nov., Lawrenceoceras ebenus sp. nov., L. larus sp. nov., Litoceras profilbekkenense sp. nov., Nyfrieslandoceras bassleroceroides gen. et sp. nov., Olenidslettoceras farmi gen. et sp. nov., Protocycloceras minor sp. nov., Proterocameroceras valhallfonnense sp. nov., Svalbardoceras sterna gen. et sp. nov., S. skua gen. et sp. nov.) are new. The diagnoses of the Cyptendoceratidae, Bactroceratidae and of Deltoceras Hyatt, 1894 are emended. Well preserved early growth stages in several species are remarkable. Turnover between the sampling horizons and between sampling intervals is high. The differences in composition, diversity and evenness of the assemblages are interpreted as reflecting changing depth and oxygenation depositional bottom conditions. The co-occurrence of endemic and cosmopolitan species is interpreted as resulting from a high vertical niche differentiation and from eustatically generated lateral shifts of facies zones. Based on calculations of phragmocone implosion depths, depositional depths of 50–130 m are plausible for the Olenidsletta Member, supporting independent evidence from biomarker signatures. Several cephalopod species of the Olenidsletta Member represent odd mosaics of morphological features of previously known cephalopods which cannot be unambiguously assigned to one of the existing cephalopod higher taxa. Results from a cladistic analysis shed new light on the early evolution of the Oncocerida and Orthocerida.
A new sepioline species, Sepiola boletzkyi sp. nov. (Cephalopoda: Sepiolidae), is described based on two specimens from the Aegean Sea (eastern Mediterranean). The type specimens are lodged in the Ege University Faculty of Fisheries Museum of Izmir (Turkey). The new species belongs to the Sepiola atlantica group sensu Naef, hence it is compared with the species in this group, namely Sepiola affinis, Sepiola atlantica, Sepiola bursadhaesa, Sepiola intermedia, Sepiola robusta, Sepiola rondeletii, Sepiola steenstrupiana and Sepiola tridens. The male of S. boletzkyi sp. nov. differs from all the others in having the combination of homomorphous ventral arm tips, eight enlarged suckers, subdivided into two groups, in the dorsal row of the distal part of the hectocotylus and a dorsal lobe complementing the copulatory apparatus. In females of S. boletzkyi sp. nov. the bursa copulatrix is large and, unlike all other species in the genus, has a large fungiform process towards the mantle wall. The discovery of S. boletzkyi sp. nov. increases to 12 the number of NE Atlantic- Mediterranean species of Sepiola.