Redescription of the enigmatic Marphysa mossambica (Polychaeta: Eunicidae) and description of two new Marphysa species from northern Australia

We investigate newly collected material of the Marphysa mossambica species group (= Marphysa group A of Fauchald, 1970) from both sides of the Indian Ocean and the western Pacific using a combined molecular (COI gene) and morphological approach. Kenyan specimens collected relatively close to the type locality of M. mossambica (Peters, 1854) closely match the original and subsequent morphological descriptions of this species.

Molecular and morphological comparisons between specimens from Kenya and the Philippines, identified as M. mossambica, and specimens from Malaysia identified as M. moribidii Idris, Hutchings & Arshad, 2014, show that M. mossambica is indeed distributed on both sides of the Indian Ocean and extends eastward to the Philippines. Re-examination of the holotype of M. moribidii provides further evidence for the placement of M. moribidii as a subjective junior synonym of M. mossambica.

We also investigated a newly collected specimen of the Marphysa mossambica group from Magnetic Island (NE Australia) and found it to be distinct from, yet sister to M. mossambica, and described it here as a new species. Finally, newly collected Marphysa specimens from Darwin (N Australia) belonging to the Marphysa sanguinea group, formed a distinct sister clade with M. iloiloenis Glasby, Mandario, Burghardt, Kupriyanova, Gunton & Hutchings, 2019 (Philippines), and is here described as a new species.

This study finds support for the existence of a widespread Indo-west Pacific Marphysa mossambica, and we provide indirect evidence for its possible anthropogenic spread; further, it demonstrates the utility of both molecular and morphological data for describing species of Marphysa.