A new genus and species of scaleworm (Polynoidae, Annelida) of presumed deep sea affinities from an anchialine cave of the Balearic Islands (W Mediterranean). Polynoidae Alcudia

A remarkable new genus and species of scale worm (Polynoidae, Annelida) was found inhabiting the bottom sediments of an anchialine cave in the North of the island of Mallorca (Balearic Islands, W Mediterranean). Specimens reach up to 2 cm in length, lack eyes and pigmentation except for a few scattered minute speckles on dorsum and ventrum, and show enlarged parapodia and sensorial appendages. A bright red brain is visible through the translucent tegument. Morphological features relate the new species with members of Eulagiscinae, currently containing eight species gathered in three genera. Pollentia perezi gen. et sp. nov. is characterised by unique morphological features: 13 pairs or elytra covering the dorsum, a single type of notochaetae and neurochaetae of two types. Whereas the new species mostly resembles members of the deep sea Bathymoorea, also interpreted herein as lacking eyes and bearing 14 pairs of elytra, molecular phylogenetic analyses are not conclusive about sistegroup relationships. Pollentia perezi gen. et sp. nov. shows some characteristic adaptations to the cave environment (depigmentation, eyelessness, elongation of parapodial appendages and swimming habits), and seems not to be closely related to the other two cave-dwelling polynoids described to date.