Three new species of Aberrapex Jensen, 2001 (Cestoda: Lecanicephalidea) have been collected from species of Myliobatis Cuvier along the coast of Argentina. Aberrapex ludmilae sp. n. parasitises M. goodei Garman in the San Matías Gulf. This species is unique in a combination of features including the shape and extent of the uterus, scolex size, testis distribution, and by lacking an external seminal vesicle and postovarian vitelline follicles. Aberrapex sanmartini sp. n. from M. goodei in San Blas Bay and A. vitalemuttiorum sp. n. from M. ridens Ruocco, Lucifora, Díaz de Astarloa, Mabragaña et Delpiani in coastal waters off Buenos Aires Province, are distinguished from all other congeners by the microthrix pattern on the scolex surface, uterus shape and extension, position of the connection of the uterine duct to the uterus, presence and extension of an external seminal vesicle, and its overall size and number of proglottids. The specimens of M. goodei and M. ridens show locally distinct cestode faunas, which are correlated with well-defined biogeographic regions. Some of these areas correspond with mating and nursery zones for species of Myliobatis., Adriana Menoret, Leonardo Mutti, Verónica A. Ivanov., and Obsahuje bibliografii
Morphological and molecular analyses of cestode specimens collected during survey work of batoid elasmobranchs and their parasites in Senegal revealed two new species of the rhinebothriidean cestode genus Stillabothrium Healy et Reyda 2016. Stillabothrium allisonae Dedrick et Reyda sp. n. and Stillabothrium charlotteae Iwanyckyj, Dedrick et Reyda sp. n. are both described from Fontitrygon margaritella (Compagno et Roberts) and Fontitrygon margarita (Günther). Both new cestode species overlap in geographic distribution, host use and proglottid morphology, but are distinguished from each other, and from the other seven described species of Stillabothrium, on the basis of their pattern of bothridial loculi. Phylogenetic analyses based on sequence data for 1,084 bp from the D1-D3 region of 28S rDNA that included multiple specimens of both new species and eight other species of Stillabothrium corroborated the morphologically-determined species boundaries. The phylogenetic analyses indicate that S. allisonae sp. n. and S. charlotteae sp. n. are sister species, a noteworthy pattern given that the two species of the stingray genus Fontitrygon they both parasitise, F. margaritella and F. margarita, are also sister species. Although species of Stillabothrium vary widely in their patterns of facial loculi, the variation does not appear to correlate with phylogeny. Most species of Stillabothrium parasitise myliobatiform elasmobranch genera of the Dasyatidae Jordan. This study brings the number of described species of Stillabothrium to nine, three of which occur in the eastern Atlantic, two of which occur off the northern coast of Australia, and four of which are from coastal Borneo., Elsie A. Dedrick, Florian B. Reyda, Elise K. Iwanyckyj, Timothy R. Ruhnke., and Obsahuje bibliografii