Phagicola Septentrionalis n. sp. (Tremodata: Heterophyidae) from the Harbour seal, Phoca Vitulina L.

INTRODUCTION During an investigation into the causes of mortality of the harbour seals (Phoca vitulina L.) in the Dutch Wadden Sea (Van den Broek & Wensvoort, 1959; Van den Broek, 1963), heterophyid trematodes have been regularly collected from the intestines. Crytocotyle lingua (Creplin, 1825) was rather common. Often together with this trematode a second, less conspicuous species was found, which appeared to belong to the Ascocotyle species complex. The taxonomy of this complex is very complicated and has recently been reviewed by American authors: Burton (1958) and Sogandares & Lumsden (1963). The present author prefers to follow the traditional opinion as expressed by Hutton & Sogandares (1958) in dividing the complex into several genera. The new species possesses the following fundamental characters: (1) spines surrounding oral sucker placed in a single row, (1) vitellaria confined to postovarial region, (3) uterus not extending in front of ventral sucker, (4) cuticle spinous on forebody only. These characters are used to distinguish the genus Phagicola Faust, 1920, from Ascocotyle Looss, 1899, sens. strict. (see Price, 1936; Burton, 1958). The species therefore is placed here in the genus Phagicola. Phagicola septentrionalis n. sp. Diagnosis (all measurements in μ). — Body elongate, consisting of a rather narrow anterior part (50-70 % of total body length) which gradually widens into a rounded posterior part. Body length 600-1000, maximum width 160-250. Cuticle spinous on anterior part of body, up to level of gonocotyl. Mouth surrounded by a single row of 16 to 20 spines of about 10-18 length. Width of oral sucker: 45-60. Dorsal lip not triangular but broadly rounded.