Proctophantastes brayi, n. sp. (Digenea: Zoogonidae) parasite of the deep-sea fish Polymixia Lowe, 1838 from Vanuatu

Proctophantastes brayi n. sp. (Digenea: Zoogonidae; Lepidophyllinae) has been found in the intestine of two species of deep-sea fish Polymixia (silver eye fish) near the island of Erromango in Vanuatu at a depth ranging from 720 to 830 m. Specimen whole mounts, histological and scanning electron microscopy preparations showed that P. brayi differs from the five known species of the genus Proctophantastes (P. abyssorum, P. gillissi, P. glandulosum, P. infundibulum and P. nettastomatis) by the following morphological characters: (i) a slit in the anterior part of the oral sucker, (ii) Laurer's canal is absent, (iii) a more extended periatrial gland than the ones in the other species of Proctophantastes, consisting of divided masses of cells and that form a conspicuous multilobated structure which does not have a membrane-bounded sac, (iv) the distal part of the metraterm has vesicle-like processes which we refer to as metratermal sacs, in addition to atrial sacs, (v) a long extension of the glandular cells surrounding the saccular bladder which extends posteriorly to the excretory pore.