Nybelinia sp.

Marmolejo-Guzman, Linda Yacsiri G., Iv, David, Hern, an G., andez-Mena, Castellanos-Martínez, Sheila & Aguirre-Macedo, M. Leopoldina, 2022, Linking phenotypic to genotypic metacestodes from Octopus maya of the Yucatan Peninsula, International Journal for Parasitology: Parasites and Wildlife 19, pp. 44-55 : 52

4.3. Nybelinia sp.

The genus Nybelinia , belonging to the Tentaculariidae family, is characterized by having a compact scolex, craspedota, four sessile bothria arranged oppositely, and four short tentacles. This genus is distributed worldwide and includes many cosmopolitan species found even in deep waters that exceed 200 m. In its adult form, it is found in the digestive system of a wide variety of species of rays, and sharks. In its larval form, it has been recorded in teleosts fish and frequently in cephalopods that act as paratenic hosts ( Palm, 2004; Tedesco et al., 2020). The characters such as compact scolex, craspedote, four triangular and sessile bothria, arranged oppositely, without scolex peduncle, four short and elongated tentacles emerging from short bulbs identify the specimens found in O. maya as belonging to the genus Nybelinia ( Fig. 2F–H , Fig. 3C). Due to the larval stage of this cestode, other characteristics that are relevant for the identification at the species level could not be observed, therefore, the determination of this larva remained at the genus level. Concerning molecular data, unfortunately, only sequences of the 18S rDNA were successfully obtained. Olson et al. (2010) confirmed through their phylogenetic analysis that Nybelinia is not monophyletic either, which is consistent with what was observed in our trees, where the analyzed Nybelina species are not grouped into a single clade; according to the phylogenetic analyses, the Nybelinia sp. ex O. maya from this study was related to a specimen identified as N. africana , however, it has no morphological similarities with that reported by Palm (2004). Both Nybelinia ( N. africana and Nybelinia sp. ) mentioned have been reported as cosmopolitan species found in waters ranging from Australia, the African coast, and Brazil ( Palm, 1997). Following the above, and based on the morphological characteristics, it can be said that the individuals found in O. maya do not belong to N. africana . For this reason, the specimens found in O. maya will remain classified at the genus level. We expect that molecular data will soon increase to complement morphological data available to date.

Figures

Fig. 2. Schematic drawings and photographs of the stained specimens of cestode parasitizing Octopus maya. Trypanorhyncha (A–D): A- Eutetrarhynchus sp.; B. Kotorella pronosoma; C- Nybelinia sp.; D- Prochristianella sp. Onchoproteocephalidea (E–G): E- Acanthobothrium sp.; F- Phoreiobothrium sp.; G- Prosobothrium sp.- Abbreviations: as = apical sucker; bot = bothridia cc = calcareous corpuscles; lo = loculi; pb = pars bulbosa; pbo = pars bothrialis; ppb = pars postbulbosa; ps = pedunculus scolecis; pv = pars vaginalis; sc = scolex; sp = septa; st = strobilo; vel = velum.