409 Dive Log Australasia December 24

Above: Chelidonura amoena . This species would seem to have some variation in colouration as well. Some can be quite dark and others much lighter, as in the example above. In some instances the spots are lacking and the darker colour presents as broad patches or a reticulation. Often there can be some translucent yellow on the caudal lobes or their margins.

Above: Chelidonura electra. A most elegant species, without the gaudiness of many of its fellows. Colour is a translucent white with bright lemon-yellow edging to the parapodia and caudal lobes and also to the lateral anterior margins of the head. There has been some discussion that this species is a variation of Chelidonura amoena but molecular sequencing has shown the two to be closely related, but distinct.

Above: Chelidonura hirundinina . This species too, has a range of colour variations, all with a similar pattern but with varying shades of blue or green lines between the black background and orange lines. The head carries a T-shaped marking and the left caudal lobe may be remarkably long in comparison to the right. Molecular sequencing is indicating that there may be a species complex, related to geographic location.

Above: Chelidonura pallida . Presents with a similar colouration as Chelidonura electra except that the yellow is much richer in hue and it is situated submarginally inside a black margin. There are yellow and black transverse bands anteriorly on the head. The pattern is also present around the posterior margin of the headshield. Specimens with random black spots inside the yellow submarginal band are known from some locations.

Above : Biuve fulvipunctata . Can be quite variable in colour, but the white/yellow coloured W-shaped pattern across the anterior margin of the headshield is a good characteristic. Mostly presents as light or dark brown in colour with white and/or orange marks or spots. Another characteristic is the long whip-like left caudal lobe that, just to confuse the identification, may be missing due to damage.

Above: Chelidonura varians . The specimen in the above image displays the typical colours and patterning - deep black background with electric-blue margins and a longitudinal medial line on the head. Different shades of blue are known and the blue lines may even be broken. Due to similarity of colouration it has been confused with Philinopsis gardineri (See Part 2 in next issue)

DIVE LOG Australasia #409 - December ‘24 21

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