Revision of the genus Cuvierina Boas, 1886 based on integrative taxonomic data, including the description of a new species from the Pacific Ocean (Gastropoda, Thecosomata)

Alice K Burridge,Arie W Janssen,Katja T C A Peijnenburg

doi:10.3897/zookeys.619.10043

Abstract

Shelled pteropods (Gastropoda, Thecosomata, Euthecosomata) are a group of holoplanktonic gastropods that occur predominantly in the surface layers of the world’s oceans. Accurate species identifications are essential for tracking changes in species assemblages of planktonic gastropods, because different species are expected to have different sensitivities to ocean changes. The genus Cuvierina has a worldwide warm water distribution pattern between ~36°N and ~39°S. Based on an integrative taxonomic approach combining morphometric, genetic, and biogeographic information, the two subgenera of Cuvierina, Cuvierina s. str. and Urceolarica, are rejected. A new species is introduced: Cuvierina tsudai sp. n., which has to date been considered the same species as Cuvierina pacifica. Cuvierina tsudai sp. n. is endemic to the Pacific Ocean and is characterised by a shell height of 7.2-8.0 mm, a moderately cylindrical shell shape, the absence of micro-ornamentation and a triangular aperture. Cuvierina pacifica is restricted to the centre of the oligotrophic southern Pacific gyre, has a shell height of 6.6-8.5 mm, a more cylindrical shell shape, no micro-ornamentation and a less triangular aperture than Cuvierina tsudai sp. n.

Highlights

Pteropods are holoplanktonic heterobranch gastropods classified in a superorder comprised of the orders Thecosomata and Gymnosomata, commonly referred to as “sea butterflies” and “sea angels”, respectively (Lalli and Gilmer 1989, Pierrot-Bults and Peijnenburg 2015)
Geometric morphometric data of shell shapes in ventral and apertural orientations were used for 168 adult specimens of Cuvierina that were registered as C. pacifica N or C. pacifica S in Burridge et al (2015)
Cuvierina tsudai and C. pacifica are similar in size but have different shell shapes, Cytochrome Oxidase I mitochondrial (COI) mtDNA and 28S rDNA

Summary

Introduction

Pteropods are holoplanktonic heterobranch gastropods classified in a superorder comprised of the orders Thecosomata and Gymnosomata, commonly referred to as “sea butterflies” and “sea angels”, respectively (Lalli and Gilmer 1989, Pierrot-Bults and Peijnenburg 2015). Pteropods play an important role in marine food webs (Jörger et al 2010), and most species occur in warm tropical and subtropical waters, the highest abundances have been observed for some (sub)polar cold water species (Bé and Gilmer 1977, Van der Spoel and Heyman 1983, Bednaršek et al 2012, Burridge et al 2016) Because of their thin-walled, aragonite shells, euthecosomes are exceptionally vulnerable to the effects of ocean acidification (e.g., Fabry et al 2008, Bednaršek and Ohman 2015, Gattuso et al 2015, Moya et al 2016). Burridge et al (2015) examined the diversity, distribution, and evolution of Cuvierina taxa using integrative geometric morphometric, molecular, and biogeographic methods They confirmed that the five species described for Cuvierina species have significantly different shell shapes and that C. pacifica consists of two disjunct morphometric groups, registered as C. pacifica N and C. pacifica S in their study. A taxonomic key is provided for the identification of Cuvierina species

Methods

Results and discussion

Conclusions