Seductorithyris septemtrionalis Sandy & Hryniewicz & Hammer & Nakrem & Little 2014, sp. nov.

• Main Authors: Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S.
• Format: Other/Unknown Material
• Language: unknown
• Published: 2014
• Subjects: Biodiversity; Taxonomy; Animalia; Brachiopoda; Rhynchonellata; Terebratulida; Loboidothyrididae; Seductorithyris; Seductorithyris septemtrionalis; Greenland; Knorringfjellet; The Beak; East Greenland; Spitsbergen
• Online Access: https://zenodo.org/record/4952592; https://doi.org/10.5281/zenodo.4952592

Seductorithyris septemtrionalis sp. nov. Figs. 11.1–11.16, 12 2011 v. partim ‘ Cyrtothyris ’ sp.—Hammer et al., p. 20, table 2, fig. 7.S. Material and occurrence. Holotype: PMO 224.896; paratypes: PMO 217.198, PMO 224.892–893, PMO 224.911, PMO 224.913, PMO 227.427?, PMO 227.430. All from seep 9. Type locality. Knorringfjellet, central Spitsbergen, N78° 18’ 49.9” E16° 10’ 58.9”. Diagnosis. As for the genus. Etymology. For the northern high-latitudes that Spitsbergen occupies (septem triōnēs [also septentrional]: the seven stars of the constellation of Ursa Major [the Great Bear, or the Plough]—a constellation visible in the northern hemisphere throughout the year and a useful aid to finding North; also “of the north” or “north wind”). Dimensions of the holotype. PMO 224.896—Length 33.7 mm, width 29.8 mm, thickness 16.1 mm. Description. Length slightly greater than width, rounded outline, with the dorsal valve almost circular. Biconvex profile with the dorsal valve tending to be flatter, but not necessarily. Smooth shell with growth lines. Erect beak. Ventral valve umbo has a broad round keel. Lateral commissure straight, anterior commissure rectimarginate. Cardinal process developed (Fig. 12, sections 0.7–1.2 mm), flat, horizontal and wide hinge plates deflected dorsally (sections 1.2–2.3), crural bases develop on inner margin of hinge plates (sections 1.6–2.3) and have a clubbed appearance initially (section 1.8). Crura are initially weakly deflected dorsally (sections 2.3–2.7). Transverse band is curved and low-arched (section 6.6, this is approximately at the mid-length of the brachidium, based on the distance the loop was traced), anterior flanges of the brachidium extend significantly beyond the transverse band (at least 5.8 mm). Loop traced to at least 11.4 mm from initial section through brachiopod (ventral umbo of sectioned specimen is damaged). Discussion. The beak of the ventral valve is erect in Seductorithyris septemtrionalis whereas in “ Cyrtothyris ” maynci from East Greenland the beak is slightly ...