"These small longitudinally striped species of Phyllidiopsis get more alike and so harder to identify every time I see another one! This picture does not show the rhinophores, so it is impossible to know what colour (black, white or orange) they might be [rhinophoral colouration is important for separating these species]. So this one seems closest to Phyllidiopsis sphingis only because of the black markings radiating outward from the outer longitudinal black stripes."