Author: Brunckhorst, 1990

Order: Nudibranchia  Family: Phyllidiidae

Maximum Size: 110 mm

Sightings: Sunshine Coast

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Phyllidiopsis shireenae Brunckhorst, 1990

To many underwater photographers the phyllidiids are the most baffling of the nudibranchs. They protest that they all look the same and that it is too difficult and too much trouble to sort them out, calling them collectively, the “lumpy ones”. While this is somewhat true of several there are others that are easy to identify.

Phyllidiopsis shireenae cannot be confused with any other phyllidiid. It is elongate and oval in shape, high-bodied, bearing a distinctive mid-dorsal longitudinal crest or ridge (rather than being dorso-ventrally flattened) that is encircled by a single black line. There are four (most usually) singular radiations from that line that extend, one each, anteriorly and posteriorly outwards to the mantle edge and also transversely at approximately the midpoint on both sides to the mantle edge. It may bear other black markings, spots, patches or lines on the dorsal crest within the encircling black line. The mantle colour is granular white to pale pink and covered with white granular tubercles that are largest and sparsely distributed on the dorsal ridge where they appear to form a longitudinal row either side of the peak of the crest. Tubercles become progressively smaller and more numerous towards the mantle edge. The tubercles contain both spicules and chemical defensive glands. There are no rhinotubercules (a characteristic of Phyllidiopsis), that is, no tubercles directly associated with the rhinophores that a number of other phyllidiid species in other genera have. The rhinophores and dorsal anal papilla, both contained, at opposite ends, within the encircling black line, are referred to as “salmon pink” in colour and are retractile into raised rims. The ventral surface is white apart from the secondary gill leaflets, situated in the hyponotal groove between the side of the foot and the mantle, that are dark grey to black and backed by a black band. The sole of the foot is unmarked. The fused oral tentacles are broad with rounded tips and often appear light pink in colour. Length has been recorded to just over 100 mm.

Distribution is broad, extending from East Africa across the Indian Ocean to the Western Pacific. The specimen pictured above was recorded on the Sunshine Coast, southern Queensland and measured 80 mm.

Like all the phyllidiids Phyllidiopsis shireenae preys upon sponges. All the phyllidiids lack radula and jaws but instead possess a highly modified foregut for suctorial feeding. By protruding their mouthparts and secreting digestive fluids upon the sponge tissue from oral glands they can suck up the resulting “soup” using their powerful muscular pharynx.

The chosen specific epithet of shireenae is explained by the author thus: “This species is named after my wife, Shireen, in recognition of her support and assistance in all aspects of this research. As ‘Shireen’ is derived from Persian for ‘that which is sweet or attractive to the eye’, it is appropriately descriptive of this nudibranch.”

Molecular sequencing indicates that Phyllidiopsis shireenae is most closely related to Phyllidiopsis xishaensis followed by Phyllidiopsis krempfi.

A handsome and distinctive species of nudibranch certainly deserving of better recognition than being lumped in with the ”lumpy ones”.

David A. Mullins – September 2020

References:
– Brunckhorst, D. J. (1990). Description of a new species of Phyllidiopsis Bergh (Nudibranchia: Doridoidea: Phyllidiidae) from the tropical western Pacific, with comments on the Atlantic species. Journal of Molluscan Studies 56: 577–584.

– Brunckhorst, D. J. (1993). The Systematics and Phylogeny of Phyllidiid Nudibranchs (Doridoidea). Records of the Australian Museum, Supplement 16: 1–107.

– Rudman, W. B., (1999 August 1). Phyllidiopsis shireenae Brunckhorst, 1993. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/phylshir and associated messages.

– Domínguez, M., Quintas, P., Troncoso, J. S., (2007). Phyllidiidae (Opisthobranchia: Nudibranchia) from Papua New Guinea with the description of a new species of Phyllidiella. American Malacological Bulletin 22: 89–117.

– Stoffels, B. E., van der Meij, S. E., Hoeksema, B. W., van Alphen, J., van Alen, T., Meyers-Muñoz, M. A., de Voogd, N. J., Tuti, Y., van der Velde, G. (2016). Phylogenetic relationships within the Phyllidiidae (Opisthobranchia, Nudibranchia). ZooKeys 605: 1–35.

– This Species Profile has been modified from a previously published article in Dive Log Magazine’s – Critter ID with NudiNotes Column, Issue: #374 (September 2019): 12 by David A. Mullins.