3D-anatomy of the ctenoglossate limpet Kaiparapelta (Vetigastropoda: Lepetelloidea)

Abstract

The anatomy of representatives of the ctenoglossate deep-water limpet genus Kaiparapelta is described on the basis of new material from the Marquesas Archipelago. The anatomy is visualized by interactive 3D-reconstructions, and histological details are depicted from serial semithin and histological sections. Vetigastropod plesiomorphies are represented by papillate cephalic tentacles, by the presence of gill-pockets (bursicles), by a papillate left excretory organ and a ramifying right excretory organ, by eggs with a vitelline layer and by statocysts with statoconia. The type of protoconch (of Kaiparapelta askewi), the limpet-shaped shell without juvenile coiling, the gill type and the conditions of the gonopericardial cavities are typical lepetelloidean characteristics. Kaiparapelta and other lepetelloidean genera (in particular Osteopelta, Cocculinella and Addisonia) share several apomorphic similarities: a snout with terminal mouth opening that lacks oral lappets and jaws, modification of the anterior oesophagus and separation of the gonoduct from the right excretory organ. Autapomorphies of Kaiparapelta are the huge head, a shell muscle consisting of two separate portions, a unique type of alimentary tract (ctenoglossate-like radula and hypertrophied, huge buccal apparatus with uniquely shaped cartilages, many openings of the midgut glands into the stomach, short intestine and rectum that passes outside the pericardium) and a quite concentrated anterior nervous system similar to that of Osteopelta. Kaiparapelta has been classified among the Pseudococculinidae, but molecular data have recently revealed this family to be a nonmonophyletic group. Accordingly, the exact phylogenetic position of Kaiparapelta among Lepetelloidea awaits resolution by further molecular studies. © 2014 © The Author 2014. Published by Oxford University Press on behalf of The Malacological Society of London, all rights reserved.