Phyllidiella rudmani Brunckhorst, 1993

Papu, Adelfia, Bogdanov, AleXander, Bara, Robert, Kehraus, Stefan, König, Gabriele M., YonoW, Nathalie & Wägele, Heike, 2022, Phyllidiidae (Nudibranchia, Heterobranchia, Gastropoda): an integrative taxonomic approach including chemical analyses, Organisms Diversity & Evolution (New York, N. Y.) 22 (3), pp. 585-629 : 611

Phyllidiella rudmani Brunckhorst, 1993

Two specimens in our collection could be confidently assigned to P. rudmani based on colouration of a pale white to bright pink dorsum with two characteristic narrow black lines on the lateral mantle (Fig. 10.2a, b). These lines do not unite in the anterior or posterior parts of the body in either specimen. The isolated tubercles in-between these two lines are tall and multi-compound, and a few small single rounded tubercles occur between these tall complex tubercles. The rhinophores are pink on the basal half and black on the upper clavus. A pink anal opening looks like a small tubercle lying between the two black lines. The hyponotum is white to bright pink, whereas the gill lamellae are black, only interrupted by the pink genital opening. The oral tentacles are entirely pink. Two sequences identified as P. rudmani and P. lizae from GenBank grouped with our specimens (bootstrap value 100; Fig. S1 ): one specimen from Raja Ampat, Indonesia (RMNH.Moll.336589), included in the analyses by Stoffels et al. (2016) looks like our specimens of P. rudmani . No information on the external features is available for the P. lizae specimen from Cheney et al. (2014) collected from Lizard Island, Australia.

The crude extract of one Phyllidiella rudmani specimen (Phpi15Bu2, Fig. 10.2a) was submitted to LCMS analysis. Several unique clusters in the molecular network (see Figs. 16 , S2) indicated secondary metabolites that are found exclusively in this specimen. Careful inspection of the mass spectrometry data and marine natural product database search (MarinLit) allowed assignment of the major constituents of this complex extract (see Fig. S9h). Unlike the other chemically analysed Phyllidiidae , P. rudmani possesses kalihinol-type diterpenes (see Figs. 16 , S4a, S9h) that are known from the sponges Acanthella cavernosa Dendy, 1922 and A. pulcherrima Ridley & Dendy, 1886 ( Braekman et al., 1994; Chang et al., 1984; Hirota et al., 1996; Patra et al., 1984; Rodriguez et al., 1994; Wolf & Schmitz, 1998). Whilst none of our specimens was photographed on Acanthella , there are a number of photographs on iNaturalist illustrating P. rudmani on cf. Acanthella including two from Sulawesi: https://www.inaturalist.org/observations/ 59862922 (Bitung, North Sulawesi), https://www.inaturalist. org/photos/34319534 (Bangka, Sulawesi), https://www. inaturalist.org/observations/41101119 (Malé, Maldives), and https://www.inaturalist.org/observations/69467738 (Phi Phi islands, Thailand).

Figures

Fig. 1 Sampling locations in Sulawesi, Indonesia

Fig.16 Phylogeny of Phyllidiidae and chemical analysis of 70 preserved specimens from three genera (Phyllidia, Phyllidiopsis, and Phyllidiella) and 19 species. a Coloured clusters were obtained with classical or feature-based molecular networking and depict families of secondary metabolites characteristic for certain clades, e.g., brominated alkaloids for the genus Phyllidia, amphilectene-type diterpenes for P. coelestis and P. elegans, kalihinol-type diterpenes for P. rudmani, as well less specific secondary metabolites (sesquiterpene isonitriles and derivatives) that were detected throughout the Phyllidiidae. The chemical structures were established either with NMR after compound isolation, or were assigned based on HR-LCMS/MS