New collections of tapeworms from the spiral intestine of the spotted estuary smooth-hound shark, Mustelus lenticulatus, in New Zealand led to the discovery of a species that appeared to be conspecific with specimens identified by Alexander (1963) as Calliobothrium eschrichti. Study of these newly collected specimens and some of Alexander's voucher material indicated that the species is new to science. Of the 15 described species in this genus, Calliobothrium schneiderae n. sp. differs from all but Calliobothrium barbarae, C. eschrichti, Calliobothrium leuckarti, and Calliobothrium hayhowi in that it is a small-bodied species that is nonlaciniate and lacks an accessory piece between the bases of its axial hooks. It differs from C. barbarae in testis number, total length, number of proglottids, and ovary shape, and differs from C. eschrichti in total length and vitelline follicle distribution. The new species also differs from C. leuckarti in total length and number of testes. It most closely resembles C. hayhowi, but differs in hook size and oncosphere packaging. The criterion suggested by Caira (1985) to distinguish axial from abaxial hooks is modified to include axial hooks being posterior in position, to accommodate species, such as C. schneiderae n. sp., in which the abaxial hooks in a pair articulate with one another along the longitudinal axis of the bothridium, rather than with their respective axial hooks. Examination of a specimen Alexander identified as Calliobothrium verticillatum suggests that this identification may also be in error, and that this large lacinate specimen of Calliobothrium also represents a new species.