Revision of chilean bathyal chitons (mollusca: polyplacophora) associated with cold-seeps, including description of a new species of leptochiton (leptochitonidae)

Abstract

The chiton fauna of Chile comprises 41 species, most of which inhabit shallow waters. The present paper gives a summary of all 14 chiton species reported from Chilean deep (bathyal to abyssal) waters, including some records that might be considered as doubtful. Leptochiton laurae n. sp. is formally established; it was formerly misidentified as L. americanus Kaas & Van Belle, 1985, but differs in the shape of the tail valve, less coarse sculpturing, in the girdle elements and radula armature. Two additional new species, Leptochiton sp. and Placiphorella sp., are discussed. ForLeptochiton medinae Plate, 1899, a lectotype is designated. Tripoplax balaenophila (Schwabe & Sellanes, 2004) n. comb. is transferred from Lepidozona Pilsbry, 1892, due to coarse sculpturing in the central areas and multi-slit insertion plates. Leptochiton belknapi Dall, 1878 and Tripoplax cowani Clark, 2008 are reported from the study region for the first time. The majority of the Chilean deep-water polyplacophorans are associated with hard substrates (authigenic carbonates) near methane seeps. The present report raises the global number of chiton species inhabiting chemosynthetic environments from 10 to 18, including some overlooked literature records from other regions.