March 19, 2003
I found this guy in a general net sweep off the pier in Provincetown, Massachusetts [Atlantic coast, USA]. It was June or July 2002 in a fairly polluted harbor with the floating docks in tidal waters of 8 feet to about 20 feet. This pier has had ongoing contruction for 2 seasons now with a sand bottom. Often in the hotter days the harbor gets very low oxygen levels causing 'fish kills' of any species kept overboard in traps. I found him on some sea lettuce (Ulva sp.) that I pulled off the dock but this area is heavily overgrown with tunicates and some hydroids. If you can give me an idea of species that would be great.
Thanks so much,
This is a species of Doto, which are small dendronotoidean nudibranchs which look very like aeolids. There are two good ways to distinguish them externally. Firstly an aeolid's cerata is usually smooth, without the tubercles seen in your animal. Secondly the rhinophores on Doto are enclosed in a tall collared sheath which is absent in aeolids.
This looks very like the animal from New York that I tentatively identified as Doto coronata in Betsey Hansen's earlier message. However as you will see in that message, there are considerable problems with identifying species of Doto at the moment. They all feed on hydroids, and it seems they probaby all are specilalist feeders on one or a few species of hydroid. So identifying them may eventually depend on identifying their food hydroid.