Phylogenetic position and systematics of the wood-associate limpet genus Caymanabyssia and implications for ecological radiation into deep-sea organic substrates by lepetelloid gastropods

• Published in: Marine ecology (Berlin, West) Vol. 37; no. 5; pp. 1116 - 1130
• Main Authors: Kano, Yasunori, Takano, Tsuyoshi, Schwabe, Enrico, Warén, Anders
• Format: Journal Article
• Language: English
• Published: Blackwell Publishing Ltd 01-10-2016
• Subjects: Annelida; Caymanabyssidae; Caymanabyssiidae; Caymanabyssiinae; Cetacea; Gastropoda; hydrothermal vent; Lepetelloidea; Marine; phylogeny; Pseudococculinidae; radula; sunken wood
• ISSN: 0173-9565; 1439-0485
• DOI: 10.1111/maec.12376

The gastropod superfamily Lepetelloidea represents an extremely diverse lineage in terms of their utilization of different deep‐sea organic substrates that include sunken wood, leaves, whale and fish bones, egg cases of sharks and rays, annelid tubes and detrital cephalopod beaks among others. They also inhabit cold seeps and hydrothermal vents, thus presenting an interesting case for the evaluation of such organic substrates as ‘stepping stones’ into these chemosynthetically nourished environments. Here we show the first molecular phylogeny of the Pseudococculinidae, a primarily wood‐dwelling family and the most speciose in Lepetelloidea. Special emphasis is placed on the genus Caymanabyssia, for which the only subfamily Caymanabyssiinae has been established, and a new species Caymanabyssia solis is described herein and compared with previously known taxa in order to reconsider the morphological characteristics of lepetelloids on wood. Bayesian and likelihood trees reconstructed using four‐gene sequences reveal that Pseudococculinidae sensu auctt. is a polyphyletic taxon that is grouped by shared plesiomorphic conditions of characters including the radula, a digestive organ, the morphology of which is often governed strongly by diet and feeding ecology. The newly reinterpreted families Pseudococculinidae and Caymanabyssiidae represent reciprocal sister clades as a basal radiation in Lepetelloidea. Sunken wood might thus have served as an ancestral habitat from which species on other substrates and vent and seep taxa were derived.