Phyllidiella sp.

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 : 609-610

Phyllidiella sp. a

The clade Phyllidiella sp. a is composed of 29 specimens and contains 26 specimens from our collections (Fig. 9.4a–d) that are externally very similar to the sister clade P. zeylanica auctt. (not the original description by Kelaart, 1858 but used by authors in error), described in more detail below. Some specimens of Phyllidiella sp. a have tuberculate ridges, and some have small, rounded, compound tubercles on the notum. A white band is also present along the mantle margin, typical of most Phyllidiella species. The rhinophores are black, but the base is red in nearly all specimens (Fig. 9.4a–d). All specimens of Phyllidiella sp. a have two or three black X-shaped lines on the middle of the dorsal notum. The species is further characterised by a grey to black anal opening on a black part of the notum. The oral tentacles, the foot sole, and the hyponotum are grey, and the oral tentacles have dark grey tips or lateral grooves. The clade Phyllidiella sp. a is supported by a bootstrap value of 99–100. However, molecular analyses provide evidence of three subclades within Phyllidiella sp. a. Two subclades are composed of our specimens and include one further sequence retrieved from GenBank ( Cheney et al., 2014; KJ001310, Lizard Island; assigned to P. pustulosa ). Network analyses ( Fig. 19 ) clearly show the distinctiveness of the two clades and thus confirm species delimitation when using the CO1 data set only.

Two further sequences retrieved from GenBank identified as Phyllidiella pustulosa by Wollscheid-Lengeling et al. (2001; AF249232, GBR, Australia) and Valdés (2003; AF430366, New Caledonia) form a sister clade to the two subclades mentioned above. The separation of this sister clade as a distinct species is not supported by our species delimitation test using the 16S data, and we therefore consider these two specimens as part of our Phyllidiella sp. a. We could not include these two specimens in our haplotype network analyses ( Fig. 19 ) because CO1 data were lacking.

LCMS analysis of the crude extracts obtained from four specimens of Phyllidiella sp. a revealed a high degree of variation. We could not identify any unique features except for presence of several non-polar metabolites (retention time of more than 20 min; Fig. S 9f), most probably sesqui- and diterpene isonitriles and sesquiterpene thiocyanates with m/z 264.18 [M + H] +. However, Phpu 16 Sa 9 and Phpu 16 Sa 90 showed a higher similarity to each other than to the other two specimens PhpuSa 24 and PhpuSa 26, thus reflecting the closer relationship of these two specimens, also according to molecular data ( Figs. 13 , S 1 ) and network analysis ( Fig. 19 ) .

Figures

Fig.19 Haplotype network of Phyllidiella sp. a (29 sequences, white circles) and Phyllidiella zeylanica auctt. (24 sequences, grey circles) based on the CO1 gene. Note the closer relationship of specimens with similar chemotypes, coloured orange and blue, respectively

Fig.13 Maximum likelihood tree of Phyllidiidae based on the concatenated data set of partial CO1 and 16S sequences. Terminal taxa on species level collapsed. Numbers at nodes are bootstrap values (1000 replicates). The genera are marked with the same colours as in Fig. S1. Numbers behind the species names indicate results of the

Fig. 1 Sampling locations in Sulawesi, Indonesia