Exploring the use of micro-computed tomography (micro-CT) in the taxonomy of sea cucumbers: A case-study on the gravel sea cucumber Neopentadactyla mixta (Östergren, 1898) (Echinodermata, Holothuroidea, Phyllophoridae)

August 10, 2021

Yves Samyn (1), Gontran Sonet (2), Cédric d’Udekem d’Acoz (1)
Zookeys, 1054, August 2021: 173–184. DOI: 10.3897/zookeys.1054.67088


Integrative taxonomy; micro-CT; Normandy; scanning electron microscopy


Sea cucumber taxonomy and systematics has in the past heavily relied on gross external and internal anatomy, ossicle assemblage in different tissues, and molecular characterisation, with coloration, habitat, and geographical and bathymethric distribution also considered important parameters. In the present paper, we made these observations and techniques in detail and complemented them with the novel technique of micro-computed tomography of the calcareous ring. We investigated a single European species, the so-called gravel sea cucumber, Neopentadactylamixta (Östergren, 1898), using recently collected material from the Chausey Islands, Normandy, France. We redescribed the species, illustrated its ossicle assemblage through scanning electron microscopy, and visualised the calcareous ring through stacking photography and through micro-CT scanning. Additionally, a DNA fragment of 955 base pairs of the 18S ribosomal RNA gene was sequenced from one specimen, which showed a high similarity with the only sequence of N.mixta publicly available. We completed this integrative study by providing a detailed distribution of the occurrence of N.mixta based on published, verifiable accounts.

How Our Software Was Used

Dragonfly was used to perform image segmentation, visualization and analysis.

Author Affiliation

(1) Scientific Service of Patrimony, Royal Belgian Institute of Natural Sciences, Vautierstraat 29, 1000, Brussels, Belgium.
(2) Joint Experimental Molecular Unit, Royal Belgian Institute of Natural Sciences, Vautierstraat 29, 1000, Brussels, Belgium.