Amphisamytha galapagensis Zottoli 1983

The smallest Amphisamytha larvae fall in the size range of the nectochaetes. Nectochaete larvae have a ciliary band circling the body near the anterior end (at right in photo) and are generally thinner for their length than Amphisamytha. Ophryotrocha larvae are similar in size and general outline to Amphisamytha, but have a prominent jaw apparatus visible through the body wall. Their parapodia are also more prominent than those of Amphisamytha.

Smallest individuals (3-4 chaetigers) have neither appendages nor distinctive morphology, as shown above left. At around 400µm and 5-6 chaetigers they develop a pair of smooth gills behind the prostomium; the adults will ultimately have four pairs, but the remaining three pairs appear much later in development. Since the smallest larvae are so featureless, it is possible that there may be more than one species represented.

Size (left): 280µm
Size (right): 435µm