Review of Baeolidia, the largest genus of Aeolidiidae (Mollusca: Nudibranchia), with the description of five new species Author Carmona, Leila Author Pola, Marta Author Gosliner, Terrence M. Author Cervera, Juan Lucas text Zootaxa 2014 3802 4 477 514 journal article 45651 10.11646/zootaxa.3802.4.5 71e8a84e-1a9b-4849-9a09-ec2023643364 1175-5326 249605 4095CA09-8EA4-4941-8286-32E95F0206AE Genus Baeolidia Recently, the monophyly of Baeolidia was recovered in the first molecular phylogenetic study of Aeolidiidae ( Carmona et al. 2013 ) . So far, Baeolidia is the largest genus within Aeolidiidae with sixteen valid species. Some species traditionally ascribed to Baeolidia such as Baeolidia fusiformis , Baeolidia benteva and Baeolidia nodosa belong to other aeolidiid genera but not to Baeolidia ( Carmona et al. 2013 ; Carmona et al . 2014b , c ). Moreover, Baeolidia macleayi , Baeolidia dela and Baeolidia chaka are transferred to this genus for the first time. Figure 1 shows the phylogenetic hypothesis for Baeolidia presented by Carmona et al. (2013 .) but showing the final names of the new species on the right side of vertical bars. Except for the Atlantic species Baeolidia cryoporos , this genus is entirely Indo-Pacific with just a few representatives in the Eastern Pacific. Only B. moebii , B. ransoni , B. harrietae and B. salaamica present populations in the Indo-Pacific as well as in the Eastern Pacific. The inclusion of Baeolidia ransoni and Baeolidia macleayi , with smooth and ribbed rhinophores respectively, and the existence of different cerata arrangements within this genus require modifying the diagnosis of the genus Baeolidia . All the traditional morphological characters (e.g. the reproductive system and radula) and new morphological traits, such as the oral glands and the rhinophoral papillae, have been deeply studied here. At a generic level, the oral glands, the different types of rhinophoral papillae, the radular morphology and the leafshaped cerata were shown to be informative. However, there are species that lack some of these characters. In fact, this genus has the greatest diversity of morphological patterns within Aeolidiidae (see revised diagnosis), which makes it very difficult to determine new synapomorphies at this level based on anatomical data. This situation has also been demonstrated with other heterobranch groups such as Tambja and Roboastra ( Pola et al. 2007 , 2008 ) as well as within Aeolidiidae with Berghia ( Carmona et al. 2014b ). Some morphological traits also have intraspecific variation. The ornamentation of the masticatory border (e.g. Baeolidia salaamica ) and the presence or absence of oral glands (e.g. Baeolidia moebii ) may vary within the same species. Although the intraspecific varibilty of the precence/absence of the oral glands has not been reported in the literature, this variation has also been observed in Limenandra nodosa ( Carmona et al ., 2014c ). Thus, in order to separate species, the colouration of the living animal can be considered as the main character in Baeolidia together with the ornamentation of the rhinophores (including the different types of papillae) and, in some cases, the radular morphology (Table 1).