Three new species of Acanthobothrium (Cestoda : Tetraphyllidea) from the ocellated electric ray, Diplobatis ommata, in the Gulf of California, Mexico

Examination of the spiral intestines of 12 female specimens of the ocellate d electric ray Diplobatis ommata from 4 sites in the Gulf of California, Me xico, in 1996 resulted in the discovery of 3 new species of Acanthobothrium : A. dollyae sp. n., A. maryanskii sp. n., and A. royi sp. n.. Acanthobothr ium dollyae and A. royi are <15 mm in total length, possess <50 proglottids , <80 testes, and a symmetrical ovary, and thus are Category I species. Aca nthobothrium maryanskii is a Category 5 species; it is >15 mm in total leng th, possesses >50 proglottids and <80 testes, and has a symmetrical ovary. Acanthobothrium royi differs from A. dollyae in the arrangement of its test es and in its possession of a shorter scolex. Acanthobothrium dollyae and A . royi differ from the 4 other Category 1 species known from the eastern Pa cific Ocean in total length, proglottid number, cirrus sac size, testis num ber, extent of vas deferens, and hook shape. Both new species differ from t he 6 other Category 1 species known from the western Atlantic Ocean in prog lottid number, cirrus sac size, ovary size, genital pore position, and hook shape. Acanthobothrium maryanskii differs from all 6 of the Category 5 spe cies known from the eastern Pacific Ocean and all 5 of the Category 5 speci es known from the western Atlantic Ocean in hook shape and in its possessio n of mature proglottids that are wider than long rather than longer than wi de. This brings the number of species of Acanthobothrium reported from rays in the order Torpediformes to 12. It brings the number of species of Acant hobothrium reported from the eastern Pacific Ocean to 37 and the total numb er of Acanthobothrium species reported from elasmobranchs in the Gulf of Ca lifornia to 7. This is the first report of tapeworms from a member of the r ay genus Diplobatis.