Observations on the “tenuis group” (Eutardigrada, Macrobiotidae) and description of a new Macrobiotus species

Abstract

A new species of the tardigrade genus Macrobiotus is described. The species, designated M. ciprianoi n. sp., was isolated from a mixture of Provence broom leaf litter and mosses, and from rock mosses collected in the Sierra de Guadarrama, Madrid (Spain). Given that Macrobiotus ciprianoi n. sp. shares several characters to members of the “tenuis group”, we assessed the taxonomic homogeneity of the group. The new species differs from those of the “tenuis group” according to a unique set of characters related with claw shape, features of the buccal‐pharyngeal apparatus, and egg morphology. Our analysis of holotypes and/or paratypes of “tenuis group” species and other Macrobiotus species with similar characters (M. bondavallii and M. caelicola) reflects the heterogeneity of this group of species as currently described.

Keywords:

• Eutardigrada
• Iberian Peninsula
• Macrobiotus ciprianoi n. sp.
• Sierra de Guadarrama
• tenuis group

Acknowledgements

The authors thank Hieronimus Dastych for providing paratypes of M. caelicola, and the Museum of Natural History of Verona for giving us the opportunity to examine Maucci's collection. This work was supported by a FAR ex 60% MURST grant from the University of Modena and Reggio Emilia, a predoctoral grant from the Comunidad de Madrid/CSIC/Museo Nacional de Ciencias Naturales de Madrid, a postdoctoral fellowship Fulbright/MEC, a project of the Comunidad de Madrid (no. 07M/0125/2000), and a grant from the European Commission programme ‘Transnational Access to Major Research Infrastructures’ awarded to BIOD‐IBERIA (Museo Nacional de Ciencias Naturales de Madrid, CSIC). We also wish to thank two anonymous referees for their constructive comments, which we feel improved greatly a previous version of the manuscript.