Svalbardoceras sterna Kröger & Pohle 2021, gen. et sp. nov.
Svalbardoceras sterna gen. et sp. nov. urn:lsid:zoobank.org:act: F4069C31-5F45-44C0-A05D-03223749C9DE Figs 12B, 16C–D, 19D, 20– 21, 22E–G, 23A, C, E, G Diagnosis Slightly curved longicones with compressed conch cross section; with shallow irregularly spaced undulations that are more pronounced in la...
| Main Authors: | , |
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| Format: | Other/Unknown Material |
| Language: | unknown |
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2021
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| Online Access: | https://zenodo.org/record/5795798 https://doi.org/10.5281/zenodo.5795798 |
| Summary: | Svalbardoceras sterna gen. et sp. nov. urn:lsid:zoobank.org:act: F4069C31-5F45-44C0-A05D-03223749C9DE Figs 12B, 16C–D, 19D, 20– 21, 22E–G, 23A, C, E, G Diagnosis Slightly curved longicones with compressed conch cross section; with shallow irregularly spaced undulations that are more pronounced in later growth stages and with fine, irregularly spaced, directly transverse imbricate growth lines which form a shallow hyponomic sinus at prosiphuncular side of the conch; thin marginal siphuncle with rSD ≈ 0.13, siphuncle positioned at concave side of conch curvature; septal necks orthochoantic to loxochoantic, connecting ring nearly tubular, weakly concave. Etymology Referring to the laridid genus Sterna Linneaus, 1758, birds which were common companions during our field work at Profilstranda, Ny Friesland. Type material Holotype Specimen FMNH-P30368. Paratypes Forty-four specimens (P30368 to P30382, P30437 to P30449, P30451 hasta P30462, P30465, P30466, P30468 to P30470; see Suppl. file 1 for list of specimens) from type locality, two from bed PO 07, fortytwo from bed PO 7.5, 4 m and 4.5 m above the base base of the Olenidsletta Member, Valhallfonna Formation, V1a trilobite zone, Blackhillsian, Floian. Two additional specimens (FMNH-P30169, FMNH-P30172) from bed PO 7.5 are apical fragments. Type locality and horizon From Profilstranda section, adjacent to Hinlopenstretet, Spitsbergen, from bed PO 7.5, 4.5 m above the base of the Olenidsletta Member, Valhallfonna Formation, V 1a trilobite zone, Blackhillsian, Floian. Description The conchs are slightly curved with an angle of expansion of conch width <ca 9° (mean angle of expansion = 6.7°, 1 st –3 rd quantile: 5.7–7.8; n = 12), and of conch height <12° (mean angle of expansion = 7°, 1 st –3 rd quantile: 6.6–9.3; n = 14). The conchs reach their largest angle of expansion in growth stages with conch heights of 10–17 mm (Fig. 20). The conch cross section is compressed with a mean rW = 0.89 (1 st –3 rd quantile: 0.86–0.92; n = 29) (Fig. 21). The conch surface is ... |
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