Buttsoceras buldrebreenense Kröger & Pohle 2021, sp. nov

• Main Authors: Kröger, Björn, Pohle, Alexander
• Format: Other/Unknown Material
• Language: unknown
• Published: 2021
• Subjects: Biodiversity; Taxonomy; Animalia; Mollusca; Cephalopoda; Orthocerida; Troedssonellidae; Buttsoceras; Buttsoceras buldrebreenense; Hinlopenstretet; Ny Friesland; Svalbard; glacier; Spitsbergen
• Online Access: https://zenodo.org/record/5793542; https://doi.org/10.5281/zenodo.5793542

Buttsoceras buldrebreenense sp. nov urn:lsid:zoobank.org:act: D6C02A7F-2CAF-44FC-A243-52AB01FCEB2C Figs 9A–B, D–E, 11B, 34–35 Diagnosis Smooth orthocones with elliptically compressed conch cross sections, widely spaced chambers (relative chamber length up to ca 0.6); with large siphuncles (rSD = 0.25) which are slightly expanded into the chambers and are eccentrically positioned (rSP = 0.21); septal necks are short orthochoanitic; continuous endosiphuncular lining and episeptal deposits are present. Etymology From Buldrebreen, a glacier near Olenidsletta, Ny Friesland, Svalbard close to the type locality of the specimen. Type material Holotype Specimen FMNH-P30421. Paratypes Four specimens (FMNH-P30422, P30423, P30428, P30430) from type locality and horizon. Type locality and horizon Profilstranda section, adjacent Hinlopenstretet, Spitsbergen, from bed PO 131, 128 m above base of Olenidsletta Member, V 2b trilobite zone, Blackhillsian, Floian. Description The holotype, FMNH-P30421, is a 44 mm long, nearly straight fragment of a phragmocone with a smooth conch surface and a compressed conch with a height of 16.7–17.3 mm and a width of 14.8– 16 mm (rW ≈ 0.9, angle of expansion of conch height 2°) (Fig. 9E). The angle of expansion is 5° in specimen FMNH-P30430, which has a conch height of 21–23 mm. The conch surface is almost smooth with faint, irregularly spaced growth lines which may form striae with a distance between 1 and 2 mm in the holotype. The growth bands or growth lines are obliquely transverse, shifted adorally at the antisiphuncular side of the conch (visible in specimen FMNH-P30423 and in holotype, Fig. 9D–E). The diameter of the septal perforation of the holotype is ca 0.25 of the corresponding conch height and positioned between the center and conch margin with an rSP of 0.21. This is identical to the mean of the rSP of all five measurements from the available specimens (mean se = 0.21; minimum measured rSP = 0.21, maximum measured rSP = 0.21; n = 5). The mean relative siphuncular diameter of all ...