Background
The mysid Heteromysis (Heteromysis) microps is reported for the first time in the Bay of Biscay. During surveys carried out between March and September 2015 in Arcachon Bay, mysid specimens were fortuitously collected from Upogebia pusilla burrows.
Results
Details on morphology, colour pattern and behaviour of H. microps are provided.
Conclusions
Commensalism was frequently mentioned for Heteromysis species but never reported for H. microps. In this study, commensalism seems to be proved between the mysid and its host U. pusilla.