TY  - JOUR
A1  - Kröger, Björn
A1  - Pohle, Alexander
T1  - Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen – a pelagic fauna with Laurentian affinities
T2  - European journal of taxonomy
N2  - 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.
T3  - European journal of taxonomy  : EJT - 783 
KW  - depositional depth
KW  - Laurentia
KW  - Cephalopoda
KW  - palaeoecology
KW  - palaeogeography
KW  - pelagic niche differentiation
KW  - protoconch
Y1  - 2021
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/62696
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-626967
SN  - 2118-9773
VL  - 2021
IS  - 783
SP  - 1
EP  - 102
PB  - Muséum National d'Histoire Naturelle
CY  - Paris
ER  -