ABSTRACT
This study describes a new species belonging to the genus Cathetocephalus from the spinner shark Carcharhinus brevipinna off the coast of Yucatan, Mexico. Cathetocephalus badilloi n. sp. has a soft scolex transversely positioned to the long axis of the strobila. The scolex is composed of an apical pad, papillate band and rugose base. The papillate band has two papillary segments; the upper segment has numerous papillae, positioned one next to the other in an irregular and heterogeneous way with a spongy texture that remains along the band. The lower papillary segment has numerous papillae positioned one next to the other, without space between them. This papillary band presents flattened rectangular papillae with a division located at the top of each the papilla, giving it the appearance of a molar tooth. Using the 28S rDNA gene and the method of Maximum Likelihood (ML) for phylogenetic analysis, we identified the present material as a new species. We did not collect specimens with mature or gravid proglottids, but since the specific identification of the members of this genus is based on the characteristics of the scolex, our proposal of the new species is determined by the morphology of this organ as well as the molecular results obtained.
ABSTRACT
Octopus maya is an endemic species of the Yucatan Peninsula. This species sustains the octopus' fishery in the region and is the only cephalopod cultured in Mexico. It is known that O. maya harbor a large richness and abundance of metacestodes that have been tentatively identified by light microscopy alone. Since the larval stages of some orders of marine cestodes lack the taxonomic characteristics shown by the adult stages and on which cestode taxonomy is based, identification down to the species level is often unattainable. Hence, the goal of this study was to characterize the parasites, for the first time, at morphological and molecular levels. A total of 60 octopuses were collected from September to December 2017 from four fishery landing ports in Yucatán: Sisal, Progreso, Dzilam de Bravo, and Rio Lagartos (15 hosts per locality). Morphology of metacestodes was characterized by light and Scanning Electron Microscopy (SEM), while the genes 18S and 28S rDNA were sequenced for molecular characterization. Based on phenotypic characters and molecular data, seven taxa of metacestodes were identified, four of them belonging of order Trypanorhyncha: Eutetrarhynchus sp., Kotorella pronosoma, Nybelinia sp., Prochristianella sp. 1; and the three remaining taxa belonging to the order Onchoproteocephalidea: Acanthobothrium sp., Phoreiobothrium sp., and Prosobothrium sp. This work provides, for the first time, molecular support to the morphological characterization of metacestodes recorded in Octopus maya.
