How to distinguish Trinchesia with blue and yellow cerata

Those who dive in winter in the waters of the Mediterranean and Eastern Atlantic Ocean have the opportunity to observe certain white nudibranchs that have cerata with a blue subapical band and a yellow apical band. It was initially thought that they were different phases of the same species, Trinchesia caerulea, quite common in the Western Mediterranean and near Atlantic, but since the paper published by Korshunova et al. (2019)…