Phyllidiella hageni Fahrner & Beck, 2000

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 : 617

Phyllidiella hageni Fahrner & Beck, 2000

Five specimens of Phyllidiella hageni ( Fig. 12.1a–d ) collected at several localities in Sulawesi demonstrate its diagnostic external appearance as described and illustrated by Fahrner and Beck (2000; three specimens from Lombok) and subsequently by Domínguez et al. (2007; two specimens from Papua New Guinea). However, the background is green in our material and not pink, and the oral tentacles are white without black tips; however, in all other colouration, our animals match the original and subsequent descriptions and illustrations. Two black longitudinal lines run the length of the mantle. Tubercles are rather flat and single, but sometimes clustered together. Black lines connecting the longitudinal lines meander between these groups of tubercles. A thin black line runs around the mantle margin. The rhinophores are black with bright green bases arising from low rhinophoral sheaths on green notum. The green anal opening is disguised between the green tubercles on green ground. The hyponotum, gills, foot sole, and oral tentacles are pale white (as described by Domínguez et al., 2007) to bright green. Some specimens with simple black lines, typical of P. rudmani Brunckhorst, 1993 can be distinguished from the latter by their tubercles: the tubercles of P. rudmani are tall and sparse, while those of P. hageni are low and densely distributed. One specimen from Raja Ampat ( Stoffels et al., 2016: fig. 10i, KX235944) was assigned to Phyllidiopsis fissurata Brunckhorst, 1993 , but clusters within our P. hageni sequences, and was probably misidentified. Despite the very distinctive fused oral tentacles in Phyllidiopsis , which are separate in Phyllidiella , these can contract to a smaller unit during fixation, thus leading to generic misidentification. Fahrner and Beck (2000), Domínguez et al. (2007), and Stoffels et al. (2016 as P. fissuratus, RMNH.Moll. 336590) described P. hageni as having a pink dorsum. Pink notal tubercles for Phyllidiella hageni should no longer be a defining character due to variability of dorsal colour. The clade is supported by a bootstrap value of 100 (intraspecific variability up to 9%) and shows the highest interspecific distances between the other Phyllidiella species (17–32%).

Figures

Fig. 12 Phyllidiella species and specimens with identifiers. Scale bars: 10 mm. 1a–d Phyllidiella hageni: a Phllsp15Bu1; b Phru18Ko1; c Phpu16Sa30; d Phha18Ko1