Euryleptidae Lang, 1884

Euryleptidae Lang, 1884 View in CoL

In Euryleptidae View in CoL , our samples covered the genera Eurylepta View in CoL , Cycloporus View in CoL , Prostheceraeus View in CoL and Maritigrella View in CoL . Unlike Bahia et al. (2017), we recovered Cycloporus View in CoL as a monophyletic genus. Morphologically, Cycloporus View in CoL is distinguished from other euryleptids by the shape of the tentacles (small protuberances on the anterior margin) and by numerous small, peripheral vesicles surrounding the body margin, from which it derives its name. These vesicles are lateral branches of the digestive system that open to the exterior via pores ( Newman & Cannon, 2002). This morphological distinctness might be the reason for the low molecular support of Euryleptidae View in CoL as a family, and the relationship of Cycloporus View in CoL with euryleptids warrants further investigation.

Three species of Maritigrella View in CoL formed a discrete clade. However, the two Caribbean species of Maritigrella View in CoL cluster with Prostheceraeus View in CoL . This apparent paraphyly led us to re-classify Maritigrella crozieri ( Hyman, 1939) View in CoL and Maritigrella newmanae Bolaños et al., 2007 View in CoL . Based on a distinct colour pattern of transverse stripes and the absence of uterine vesicles, Newman & Cannon (2000) erect the genus Maritigrella View in CoL for a group of euryleptid polyclads from the Indo-Pacific. Relying on similar striped colour patterns and the absence of uterine vesicles, Newman et al. (2000) then synonymized and reclassified Pseudoceros crozieri Hyman, 1939 , Prostheceraeus zebra Hyman, 1955 View in CoL and Cryptoceros crozieri Faubel, 1984 into Maritigrella crozieri ( Hyman, 1939) View in CoL . Although the reclassification into Euryleptidae View in CoL is warranted ( Pseudoceros View in CoL belongs to Pseudocerotidae View in CoL ; Cryptoceros has been abolished; Litvaitis et al., 2010), Hyman’s (1955b) description of Prostheceraeus zebra View in CoL clearly states that the species is lacking uterine vesicles. Hence, the fact that uterine vesicles may be absent in some species of Prostheceraeus View in CoL indicates that they are of little phylogenetic value in this group. Consequently, we here move Maritigrella crozieri View in CoL to Prostheceraeus View in CoL , to form Prostheceraeus crozieri View in CoL comb. nov. Additionally, after a re-examination of our specimens, a comparison with Hyman’s (1955a) original description and holotype material and the results of our molecular analysis, we recognize Maritigrella newmanae View in CoL as a junior synonym of Prostheceraeus floridanus View in CoL .

Traditionally, morphological traits for the identification of euryleptids have focused on tentacle shape (pointed, slender vs. small anterior bumps), the presence or absence of marginal pores, the number of uterine vesicles (none, two or multiple) and diverse colour patterns. Characters of the male reproductive system are of little taxonomic value, because of their uniformity and resemblance to pseudocerotid systems. Although some euryleptids may be identified by unique colour patterns (e.g. some species of Prostheceraeus and Maritigrella ), the inadequacy of species-specific characters compels a reliance on molecular data for positive species identification, especially in Eurylepta .