Pseudothyone labradorensis sp. nov., external and internal morphology A, C holotype, before preservation (A) and preserved in ethanol (C) B, D paratype, before preservation (B), in ethanol (D) E tapered posterior body part in paratype F tube feet in holotype G body-wall skin with dense layer of ossicles H segments of calcareous ring in holotype I dissected anterior part in paratype. Labels: ap anal papillae, g gonad, pv Polian vesicle, rm retractor muscle.