Thuridilla neona? off Townsville, QLD

Note added 31 Oct 2005: This is most probably a colour variant of  T. neona. See message #15140.

Dear Daniel,
This is an interesting find. Despite Terry Gosliner's exhaustive review of the genus Thuridilla we still have some work to do. Your animal has similarities to T. undula, T. neona and T. indopacifica.

In the original description of T. undula  it is hard to see from the photo, or from the description, whether the orange parapodial border has a uniform width or not. The Fact Sheet photo from the Solomon Ids suggests it doesn't. It seems to have whitish parapodia with an orange border, a black submarginal line, and diffuse blue patches. Your animal is possibly a variation of this species, but the bright green colouration in your animal, which I suspect is from the digestive gland, may be masked by opaque whitish pigmentation in the Solomons animal. However, the thin yellow line, alongside the black line, has not previously been reported from T. undula.

In T. neona - there are thin orange, then black, then blue lines, of equal width, running parallel to the edge of the parapodia. The parapodia are described as 'greenish' by Gosliner, or orange brown in Forum photo.  

T. indopacifica does have greenish parapodia, but the edge of the parapodia has thin black, orange and black lines and then a row of blue spots, running parallel to the edge of the parapodia. There are whitish spots all over the parapodia as well.

I suspect your animal may be a colour variation of T. undula. If you have a dorsal photo of the head, it might show us the colour pattern of that region. Markings on the rhinophores and head may turn out to be important in identification.

Best wishes,
Bill Rudman