Disculiceps galapagoensis n. sp. (Lecanicephalidea: Disculicepitidae) from the shark, Carcharhinus longimanus, with comments on D. pileatus

Abstract

Disculiceps galapagoensis n. sp. from the spiral valve of an oceanic whitetip shark, Carcharhinus longimanus, collected near the Galapagos rift is described and figured. It differs from D. pileatus (Linton, 1891) Joyeux and Baer, 1935, the only other species currently recognized in the genus, as follows: The collar is much wider in proportion to the cushion, the cushion tapers gradually to meet the collar rather than meeting it abruptly, and the vas deferens is much less extensive and convoluted. In addition, scanning electron microscopy reveals that the surface of the cushion in the new species bears a regular pattern of pores arranged in numerous parallel rows, whereas the cushion of D. pileatus apparently does not. The family diagnosis of the Disculicepitidae, and the description of D. pileatus are emended. The systematic position of the genus is discussed and it is recommended that, for the present, the group remains as a family in the order Lecanicephalidea.