A new cestode (Tetraphyllidea: Phyllobothriidae) in elasmobranchs from the Taiwan Strait

In total, 20 fanrays, Platyrhina sinensis (Rajiformes: Rhinobatidae), collected from the Taiwan Strait, were examined. A new phyllobothriid genus and species (Tetraphyllidea: Phyllobothriidae) was found and described. Biotobothrium platyrhina n. gen., n. sp. is assigned to the Rhinebothriinae Euzet, 1953, because it possesses 4 stalked bothridia that are each divided by septa into numerous small facial loculi but that lack apical suckers. The new genus and species is clearly different from any other in Rhinebothriinae in that each bothridium bears 2 sets of 5 small facial loculi, with 1 set located at each of the distal ends of the bothridium, rather than facial loculi throughout the entire distal surface of the bothridium, as is seen in all other genera in the subfamily. This character has not been previously reported for members of Rhinebothriinae. In addition, the testicular arrangement in the anterior quarter of the proglottid is unique. The posterior range of the vas deferens almost reaches the ovarian bridge, and the morphology of the cirrus sac and several other morphological characters are at variance with presently described species in the subfamily.