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Naisdoris labalsaensis

Species Profile

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Naisdoris labalsaensis

Author: Paz-Sedano, Cobb, Gosliner & Pola, 2024

Order: Nudibranchia  Family: Goniodorididae

Maximum Size: 15 mm

Sightings: Sunshine Coast

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Naisdoris labalsaensis Paz-Sedano, Cobb, Gosliner & Pola, 2024

CLARIFICATION ABOUT THE DISCOVERY AND PREVALENCE OF THIS SPECIES
We believe that Julie Schubert and Terry Farr were the first to record this species, anywhere, (undescribed at the time) back on 14th January 2012 on Currimundi Reef, an offshore reef on the Sunshine Coast of Queensland, Australia.

It was then sighted a second time on 17th September 2015 in the Mooloolah River at La Balsa by Julie, Terry and myself – the first recording from the river. This species is not commonly sighted. The sightings are all related to odd times, approximately in the last quarter of the year. All of the sightings recorded during each of those times refer to the same small group of specimens. It is not recorded in the Mooloolah River every year.

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The Okenia are a successful group, if success be measured by a speciose genus. There were nearly 60 described species of Okenia globally and more than a dozen putative, known, but still undescribed from the Indo-Pacific region alone. Over the years more than ten genera have been synonymized with Okenia. Compared to other major genera of the Goniodorididae, such as Trapania and Goniodoris, species of Okenia exhibited a greater diversity of body form. That specious genus with the diversity of body form has recently come under review, and through molecular sequencing, three of those genera have been restored and new genus raised (Paz-Sedano, Moles, et al, 2023).

The body of Naisdoris labalsaensis is elongate, flat, a little expanded anteriorly and tapering posteriorly. It possesses a distinct and continuous notal rim. The anterior portion of the notal rim carries a number of small and stubby papillae each side. The anterior-most pair (occasionally there are four) however, are directed forwards and are very elongate, even whip-like in appearance, although these may be damaged through some misadventure and therefore may present instead, as mere stubs of their former selves. At a small distance posterior to the rhinophores the stubby papillae continue evenly spaced but are located slightly inside to the notal rim proper. The mid-dorsum too carries a set of even smaller stubs and these are arranged in an elongate oval around the midline. The gills emerge from the posterior end of this oval being long and trailing posteriorly. Being a phanerobranch sea slug, the gills cannot retract into pockets. Behind the gills the notal brim converges towards the midline and terminates into two very long papillae on each side. The tail is devoid of papillae or other adornment. The rhinophores are large, carried erect and bear many fine “congested” lamellae posteriorly while its tip is smooth and bluntly pointed.

Naisdoris labalsaensis has a stunning and complex colouration. The background colour is pink, the lateral papillae are yellow tipped with brown dashes between each that eventually also run up onto the two posterior pairs of papillae that are basally pink and distally white. There is a long band of white pigment laterally on the notal brim, both sides, where the papillae run more medially. The two long anterior whip-like papillae have yellow bases with brown spotting and turn completely brown for the distal two thirds. In between and posterior to the rhinophores is a large white patch that bifurcates into two white lines within which lie the mid-dorsal papillae stubs that are yellow themselves with brown spots in-between some. The white pigment of these lines may be discontinuous or even peter out completely. The rhinophores are pink anteriorly sometimes with scattered white pigment while posteriorly their lamellae are translucent white for the basal half and brown for the distal half, as is the tip. The gills are translucent white basally, with some opaque white distally and yellow tipped.The foot and sides of the body are translucent. The tail is pink dorsally sometimes with white pigment posteriorly.

Recorded in size up to 7 mm.

The spawn is laid flat onto the substrate as a full or partial circle in a wide ribbon of white egg capsules.

Distribution to date is only recorded from the Sunshine Coast of Eastern Australia on the offshore reefs and in the Mooloolah River.

The specific epithet labalsaensis is a reference to La Balsa Park dive site in the Mooloolah River, Sunshine Coast, Australia, the species type locality.

Previously here as: Naisdoris cf.liklik, but had some similarities to Naisdoris liklik such that we misidentified it as the latter for several years, until we photographed the real Naisdoris liklik in the Philippines and Ambon, and subsequently read its description more carefully.

Differences to Naisdoris liklik (Gosliner, 2004): The two anterior-most papillae are very long and whip-like. None of the other papillae are long. The papillae of the notal brim run more medially, off the notal brim, once posterior to the rhinophores. There is no mid-dorsal serrated crest anterior to the gills. It also bears two medial rows of stubby papillae.The gills are not covered in solid white pigment. Colours and patterning are substantially different.

Originally known on this site as Okenia cf. liklik – Change effected to Naisdoris cf. liklik 22/12/2023 (Paz-Sedano, Moles, et al, 2023) – Further change effected upon its formal description to Naisdoris labalsaensis 01/05/2024 (Paz-Sedano, Cobb, Gosliner & Pola, 2024)

David A. Mullins – May 2021 (Updated December 2023 & May 2024)

References:
– Gosliner, T. M. (2004). Phylogenetic systematics of Okenia, Sakismaia, Hopkinsiella and Hopkinsia (Nudibranchia: Goniodorididae) with descriptions of new species from the tropical Indo-Pacific. Proceedings of the California Academy of Sciences 55, 125–161.

– Rudman, W. B. (2004). Further species of the opisthobranch genus Okenia (Nudibranchia: Goniodorididae) from the Indo-West Pacific. Zootaxa, 695: 1-70.

– Gosliner, T. M., Valde ́s, A ́. & Behrens, D. W. (2018). Nudibranch & Sea Slug Identification – Indo-Pacific, 2nd Edition. New World Publications, Jacksonville, Florida, USA.

– MolluscaBase eds. (2021). MolluscaBase. Okenia Menke, 1830. Accessed through: World Register of Marine Species (WoRMS) at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=138042 on 2021-05-25

– Paz-Sedano, S., Moles, J., Smirnoff, D., Gosliner, T. M. and Pola, M. (2023). A combined phylogenetic strategy illuminates the evolution of Goniodorididae nudibranchs (Mollusca, Gastropoda, Heterobranchia). Molecular Phylogenetics and Evolution 107990

– Paz-Sedano, S., Cobb, G., Gosliner, T. M. & Pola, M. (2024). Filling gaps in the knowledge of Goniodorididae taxa (Mollusca, Gastropoda, Nudibranchia) with description of seven new species. Zootaxa. 5443(4): 523-547.

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