Cretaxinus hurumi Hryniewicz & Little & Nakrem 2014, sp. nov.

• Main Authors: Hryniewicz, Krzysztof, Little, Crispin T. S., Nakrem, Hans Arne
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2014
• Subjects: Biodiversity; Taxonomy; Animalia; Mollusca; Bivalvia; Lucinida; Thyasiridae; Cretaxinus; Cretaxinus hurumi; Svalbard; Spitsbergen
• Online Access: https://doi.org/10.5281/zenodo.4929787; http://treatment.plazi.org/id/A2311D4D9F3DE30D04E6FEC7FE46286E

Cretaxinus hurumi sp. nov. (Figures 13 K–N, 15, 16 A–G) 2011 Thyasira sp. —Hammer et al. , fig. 7a–c, tab. 2. Etymology. After Jørn H. Hurum, leader of 2004–2012 Svalbard expeditions of the Natural History Museum, University of Oslo. Type locality. Seep 9, Knorringfjellet, Spitsbergen, 78°18’49.9”N 16°10’58.9”E. Type mterial. Holotype: PMO 217.277; an internal mould with shell partially preserved, showing a triangular outline, external ornament, a sulcated posterior margin and a thick, short, external ligament. Paratypes: PMO 217.172; an almost complete internal mould showing outline and anterior adductor muscle scar. PMO 217.175; a fragment of an internal mould and silicone rubber cast showing posterior adductor muscle scar and posterior pedal retractor. The silicone rubber cast shows the cardinal area with an elongated resilifer. PMO 217.540; complete internal mould showing the triangular outline, well impressed rounded posterior adductor muscle scar and deep escutcheon. PMO 225.128; an almost complete internal mould showing anterior adductor muscle scar and crosssection through the external ligament and ligament nymphs. PMO 225.136; an internal mould showing very weak anterior adductor muscle scar. Material examined. 56 specimens, all articulated or semi-articulated internal moulds with variable amounts of shell preserved. See Appendix 1 for list of specimens. Dimensions. 23–56.5 mm in length, 12.6–50 mm in height, 19–39 mm in width. See Figure 17 A–D and Appendix 2K for details. Diagnosis. As for the genus. Description. Shell large, subtriangular in outline, up to 56.5 mm long, 50 mm high, and 39 mm wide. Average H/L ratio ≈ 0.85, W/L ≈ 0.75, and W/H ≈ 0.88. Shell less than 0.5 mm thick, covered with commarginal growth lines. Umbonal angle usually larger among smaller specimens, which have concave anterodorsal and posterodorsal margins. Beaks incurved, prosogyrate, not prominent, positioned closer towards the anterior, with average Pl/L ≈ 0.67. Umbonal angle slightly acute. Lunule large, deep, heart-shaped. ...