DIVE LOG AUSTRALASIA FEB 2025 ISSUE 410

Above: A species wide-spread in the Indo-Pacific, Philinopsis pilsbryi can appear in huge populations when conditions are suitable and yet be scarce at other times. From Left to right: A typical adult with the light and dark reticulate pattern; A close-up of the head showing the distinctive crest that houses its long folded and protrusible buccal bulb, right eye spot and the anterior lateral groove between parapodia and body that channels water over its Hancock sensory organ to the mantle cavity and gill; A juvenile of the species with its thin-lined reticulate pattern.

Above: Black or dark brown with blue edging, Philinopsis gardineri also exhibits a thin white line to the posterior edge of the headshield - just discernible in this image. The anterior crest is distinctively bubble shaped. Similar to Chelidonura varians in colour and pattern with the dark base and blue edging, but not possessing the long tails of that species/genus.

Above: The distinctive patterning gives rise to the name of Philinopsis lineolata . It presents with a light background colour with transverse black lines down the entire length of the body and parapodia. Variation in the width of the black transverse lines give a range of appearance as does a diversity of the lighter background colour from white to yellow.

Above: This specimen Left: could possibly be Philinopsis reticulata (Milne Bay, PNG). The patterning is highly variable in that species based on a dark reticulation over a lighter background. Sometimes the reticulation is open and other times it is so tight as to appear more like spots. Blue colouration (purplish here) on the anterior inside edges of the parapodia and caudal lobes is also considered diagnostic. Right: Another specimen (Philippines) that could possibly be identified with Philinopis reticulata but would be an extreme variation. Currently listed as Philinopsis sp. 02.

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DIVE LOG Australasia #410 - February‘25