Fig. 51. Single most parsimonious trees of four separate cladistic analyses to test different a priori interpretations and hypotheses. A–B. Shape of siphuncular segments of critical species interpreted as "tubular". C–D. Shape of siphuncular segments of critical species interpreted as "concave". B–D. Analyses with several topological constraints enforced under an assumption of the monophyly of the Endocerida, Oncocerida, and Orthocerida (see methods for details). Critical species are: Ethanoceras solitudines sp. nov., Olenidslettoceras farmi gen. et sp. nov., Svalbardoceras sterna gen. et sp. nov., and Valhalloceras floweri Evans & King, 1990. Grey boxes indicate established order level classification of species in the analysis. Values above branches are Bremer supports (if> 1), values below branches are bootstrap supports (absolute and GC frequencies).

Published as part of Kröger, Björn & Pohle, Alexander, 2021, Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities, pp. 1-102 in European Journal of Taxonomy 783 (1) on page 80, DOI: 10.5852/ejt.2021.783.1601, http://zenodo.org/record/5793422