Underwater Photograph for March 2024: Cyerce Sp. (Butterfly Seaslug) by Jack Fung

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The body is translucent white, coloured by a characteristic dark brown pattern which essentially covers the entire dorsum, except the area around the eyes, head, pericardial area, the area ahead of the rhinophores and their tips, but the transparency of the rest of the body often gives the animal a uniformly coloured look. The cerata are very wide and somewhat inflated, very mobile and easily autotomized if the animal is disturbed, leaving behind these organs that change shape for hours to distract the attention of predators.

The animal quickly regenerates the lost cerata. Both the dorsal and ventral surfaces of the cerata are translucent white, except for a row of blunt brown digitations at the edges of the cerata that in some specimens appear as a brown line along the edge of each cerata, missing in the smaller cerata on the front of the animal. Small white scores were also observed forming a band at the tips of the cerata, corresponding to opalescent glands, most likely of a defensive character.

The digestive tract is dark green or almost black-brown and can be seen by transparency in different parts of the body, both dorsal and ventral. All head tentacles are wound, the rhinophores bifurcated (characteristic of this family), of which the top one is coloured brown but the lower one and oral tentacles are light coloured. The previous propodial margin is bilabiate, and the foot has a transversal mesopodial slit. The anus is located laterodorsal on the right side, visible as a light-coloured papilla, located right ahead of the pericardial prominence. The largest specimen Thompson found measured 11 mm in length. 


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This piece was prepared online by Panuruji Kenta, Publisher, SEVENSEAS Media