August 5, 2003
From: Alicia Hermosillo
Dear Dr. Rudman,
I thought very interesting the message of the giant Tylodina perversa. As you correctly mention, in few occasions all of us come about true giants for the species.
This guy I am sending, besides showing a brighter coloration than usual for this species, Hypselodoris agassizii, it was a true giant, over 10 cm long. (Islas Marietas, Bahia de Banderas), June 6th, 2003.
For a specimen this big and chubby, it could be it was parasitised very young by a copepod (or something related) that damaged the gonads. So when the animal does not use any of its energy in growing gonads and reproducing, uses it to grow. I did not want to collect and dissect him and prove this since I figured he had suffered enough already.
firstname.lastname@example.orgHermosillo, A., 2003 (Aug 5) A comment on giant slugs. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/10644
Being rendered infertile by a parasite is an interesting, if unhappy, idea. I hope next time you find a giant you are feeling a little less kind, and can test your hypothesis by having a look inside. It is also interesting how the background colour of the animal can look quite different in colour in your two photos.
Hypselodoris agassizii is from Mexico
From: Alicia Hermosillo, March 26, 2002
Hypselodoris agassizii from Mexico
From: Alicia Hermosillo, March 22, 2002
Hypselodoris agassizii & Chr. sphoni
From: Terry Gosliner, February 25, 2000
Hypselodoris agassizii from Costa Rica
From: Erwin Koehler, February 23, 2000