Four new species of Mesomyzostoma (Myzostomida: Annelida)

ABSTRACT

Mesomyzostoma Remscheid, 1918 currently includes three described species that live in the coelom and/or gonads of comatulid crinoids: Mesomyzostoma reichenspergeri Remscheid, 1918, Mesomyzostoma katoi Okada, 1933 and Mesomyzostoma lanterbecqae Summers and Rouse, 2014 in Summers, Al-Hakim et al. 2014. Here we describe four new species of Mesomyzostoma and assess their phylogenetic relationships using 18S rRNA, cytochrome oxidase subunit I and 16S rRNA sequence data. We also designate a neotype for M. katoi as the original types appear to be lost. We record M. reichenspergeri from the Australian Great Barrier Reef and from northern Papua New Guinea, but samples from the type locality (Aru Islands, Indonesia) and previously recorded host are needed for confirmation. The new species of Mesomyzostoma are one Japanese species: Mesomyzostoma okadai sp. nov., and three Australian species: Mesomyzostoma lobus sp. nov., Mesomyzostoma leukos sp. nov. and Mesomyzostoma botulus sp. nov. The first infects the coelom of crinoid arms and pinnules, and the other three are found in crinoid oral discs. We also record M. leukos sp. nov. and M. botulus sp. nov. from Papua New Guinea. Phylogenetic analyses suggest that M. okadai sp. nov. is the sister group to all other Mesomyzostoma.

KEYWORDS:

• Parasitism
• taxonomy
• phylogeny
• Echinodermata

Acknowledgements

We thank Fredrik Pleijel and Ejiroh Nishi for valuable field assistance in Japan and Charles Messing for similar help in Australia. Dieter Fiege, Mark Grygier and Ejiroh Nishi are thanked for valuable assistance in establishing the status of type materials of M. katoi or M. reichenspergeri. Thanks also to Mark Grygier and an anonymous reviewer for their valuable comments on the manuscript.

Additional information

Funding

This research was funded by an Australian Research Council QEII fellowship to GWR, a US National Science Foundation Graduate Research Fellowship to MMS, NSF grant DEB-1036368 (to GWR), and a Postdoctoral Research Associate grant from the National Fund for Scientific Research, Belgium (FNRS) to DL. The National Fund for Scientific Research, Belgium (FRFC) provided financial support for SEM and some molecular analyses. This research is a contribution of the ‘Centre Interuniversitaire de Biologie Marine’ (CIBIM).