A New Species of Pickworthiidae (Gastropoda, Caenogastropoda) from Easter Island, Southeastern Pacific

摘要

The family Pickworthiidae Iredale, 1917 consists of microscopic, elongate rissoiform to planispiral gastropods with a characteristic circular rimmed aperture and a deep sinusigeral notch in the variably tilted protoconch (Bouchet & Le Renard, 1998; LeRenard & Bouchet, 2003). A molecular phylogenetic study has shown a close relationship between Pickworthiidae and Cerithioidea (Takano & Kano, 2014). During the last two decades shells of pickworthiids have been obtained through extensive collecting expeditions in the tropical Indo-West Pacific conducted mainly by the National Museum of Natural History, Paris and the National Museum of Nature and Science, Japan (Kase, 1998a-c, 1999; Le Renard & Bouchet, 2003). Pickworthiids are a particularly large component of dead shell assemblages in tropical submarine caves and caverns (e.g., Kase & Hayami, 1992; Kase, 1998a-c, 1999). The Pickworthiidae heretofore comprises 14 genera, 65 Recent species and 12 fossil species (Le Renard & Bouchet, 2003; Janssen, 2004; Espinosa et ai, 2006; Moolenbeek & Mussai, 2010; Rolan, 2005; Moolenbeek, 2008; Santos & Franca, 2008; Moolenbeek & Hoenslaar, 2010; Kase & Letourneux, 2013; Alhejoj et al., 2016).