A new genus and three new species of Anthocephaliidae (Cestoda, Rhinebothriidea) from the round fantail stingray, Taeniurops grabata (Chondrichthyes, Dasyatidae) from the Mediterranean Sea and Atlantic Ocean

Two new species of Scalithrium (Cestoda: Rhinebothriidea) from rajiform batoids of the Argentine Sea

Two new species of Scalithrium Ball, Neifar Euzet, 2003 were found in rajiform batoids of the Argentine Sea: Scalithrium kirchneri sp. nov., parasite of the Rio skate Rioraja agassizii (Mller Henle) from waters off Buenos Aires Province, and Scalithrium ivanovae sp. nov., parasite of the La Plata skate Atlantoraja platana (Gnther) from waters off Ro Negro Province. Scalithrium kirchneri sp. nov. and S. ivanovae sp. nov. differ from their congeners by having a particular combination of features including: total length, number of loculi on the distal bothridial surface, absence of bilobed bothridia and number of testes. Additionally, S. kirchneri sp. nov. can be distinguished from S. ivanovae sp. nov. by the presence of a vaginal sphincter and seminal receptacle, by the position of the entrance of the vas deferens into the cirrus sac, and by the microthrix pattern on the proximal bothridial surface. Based on this and previous studies, we conclude that some morphological traits may not be considered as key characters for the generic diagnosis of Scalithrium due to their variability within the genus. These characters include the musculature disposition in bothridial transverse septa and position of the entrance of the vas deferens into the cirrus sac, which certainly complement other diagnostic characters at a specific level. The discovery of these two species represents the first record of the genus Scalithrium in temperate waters of the Southern Hemisphere. In addition, this study is the first to undoubtedly identify batoids from the order Rajiformes as hosts for Scalithrium.

The First Report and Description of a New Species of Rhinebothrium from a Dasyatid Stingray from the Brazilian Northeastern Coast with a Review of the Distribution of the Genus throughout Endemic Marine Ecoregions

Here we describe a new species of RhinebothriumLinton, 1890, from Hypanus guttatus (Bloch and Schneider). Rhinebothrium ramosi n. sp. can be differentiated from all 51 valid species of the genus by having 4-5 testes and uterus that extends throughout the entire length of the proglottid. Only 8 of the above species closely resemble R. ramosi in total length (Rhinebothrium bunburyense, Rhinebothrium chollaense, Rhinebothrium corbatai, Rhinebothrium dasyatidis, Rhinebothrium kruppi, Rhinebothrium lintoni, Rhinebothrium margaritense, and Rhinebothrium reydai). Despite the resemblance, R. bunburyense, R. corbatai, R. dasyatidis, R. lintoni, and R. margaritense can be distinguished from the new species by possessing a larger number of proglottids. The remaining 3 species (R. chollaense, R. kruppi, and R. reydai) overlap in total length and number of proglottids with R. ramosi. However, they can be distinguished from the new species by possessing a single posterior-most bothridial loculus instead of arranged as a pair, as found in the new species. This is the first report of the genus from the coastal waters of Brazil and brings to 52 the number of valid species for this genus. Additionally, we use the patterns of infection and distribution for species of Rhinebothrium to make predictions of expected diversity within the genus, especially for unsurveyed hosts in endemic marine ecoregions of the world.