Nembrothinae is a colourful subfamily of nudibranch polycerids, which despite its large size and striking appearance, needs to be more thoroughly studied. The available scientific information about this subfamily is very recent, and pictures of living undescribed species become available every day. Nevertheless, the lack of associated material for morphological, anatomical, and molecular analysis results in scarce additional studies. In this paper, five novel species are described: Roboastra ernsti sp. nov., Roboastra nikolasi sp. nov., Tambja brasiliensis sp. nov., Tambja crioula sp. nov., and Tambja kava sp. nov. In addition, Tambja divae (Marcus, 1958), a species previously known only from the original description, is redescribed and additional data and comments on Tambja cf. amakusana Baba, 1987 and Tambja marbellensis Schick and Cervera, 1998 are provided. Molecular data (H3, COI and 16S genes) for all these novel species and some additional ones were obtained and included in a previous molecular database. Maximum-likelihood, maximum-parsimony and Bayesian analyses were carried out. The phylogeny presented here has revealed Nembrothinae to be an intricate and challenging group of nudibranchs to study. Intermediate missing species seem to be critical to understanding the evolutionary relationships within this group.
© The Willi Hennig Society 2014.