Placida cremoniana from New South Wales

May 12, 2001
From: Bill Rudman

To accompany Thierry Thibaut's message about Placida cremoniana from the Mediterranean, here are some photos of an animal from Sydney, NSW, Australia, which seems externally to be identical. It is sometimes quite common intertidally in tangled mats of filamentous green algae. Previously on the Forum I have called it Stiliger cremoniana. Externally Stiliger and Placida differ in whether the rhinophores are simple (Stiliger) or enrolled (Placida). From the photo (Lower left)you can see that the rhinophores are enrolled so it seems that this species is found in both the Mediterranean and the Indo-West Pacific. Although it was first described from the Mediterranean it does not necessarily mean it originated there. It is just as likely it travelled there on the bottom of a sailing ship as vice versa. In New South Wales I have records from Sydney south to Eden.

PHOTOS: Long Reef, Sydney, intertidal April 1985. Many specimens on filamentous green algae 12-20mm long. Lower Left: Head and rhinophores. Lower Right: Showing diverticula in cerata. PHOTOS: Bill Rudman

Best wishes,
Bill Rudman

Rudman, W.B., 2001 (May 12) Placida cremoniana from New South Wales. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/4321

Copyright © Australian Museum, 1998-2010