Two new species of Tubiluchus (Priapulida) from Japan

Two new species of the genus Tubiluchus (Priapulida) are described from marine sediments in Japan. Both species were found to differ in a number of fine structural characters (the pharyngeal teeth, the buccal tube and the scalids) from previously described species. Tubiluchus soyoae n.sp. differs from other species by the structure of the male genital region, a size-increase of scalids from anterior to posterior and the structure of scalids in the first ring. There are no anterior buccal papillae. Pharyngeal teeth possess the usual two combs and those of the anterior ring possess an additional third comb which is unknown from other species. Intraspecific variability of 18S rDNA and COI sequences was low (0.17% and 0.76%, respectively), but interspecific variability of 18S rDNA was 1.43-3.32% within the genus. Tubiluchus pardosi n.sp. differs from other species by the fine structure of scalids, in particular the division into a basal part with smooth cuticle and a distal part with fine cuticular hairs. Further differences are in the structure of the pharyngeal teeth in the anterior ring, the transition between pectinate teeth and fimbrillae and in the structure of the buccal tube.