Morphological abnormalities in the stauromedusa Haliclystus auricula (Cnidaria) and their possible causes

Morphological abnormalities were observed in a population of the stauromedusa Haliclystus auricula in southern Chile. A total of 144 abnormal specimens was observed out of 3790 Stauromedusae sampled. The following abnormalities are described: individuals lacking arms (73%), with more than eight anchors (11%), more than eight arms (8%), lacking anchors (4%) and one individual with tentacles in abnormal locations. An individual with two peduncles, one with two mouths and one twin-like individual are recorded for the first time in this species. Their possible causes are discussed. © 2008 Marine Biological Association in the United Kingdom.