5 NEW SPECIES OF ACANTHOBOTHRIUM VANBENEDEN, 1849 (EUCESTODA, TETRAPHYLLIDEA, ONCHOBOTHRIIDAE) IN STINGRAYS FROM THE GULF-OF-NICOYA, COSTA-RICA

Five new species of Acanthobothrium are described in stingrays from th e Gulf of Nicoya, Costa Rica. Acanthobothrium costarricense n. sp. in Dasyatis longus, most similar to Acanthobothrium lilium, Acanthobothri um lineatum, and Acanthobothrium himanturi, has bothridial hooks avera ging 125 mu m (lateral) and 145 mu m (medial) long, an average of 47 t estes per proglottis, cirrus sacs averaging 187 mu m long, and asymmet rical ovarian lobes with poral lobes reaching the posterior margin of the cirrus sac, and aporal lobes reaching the middle of the cirrus sac . Acanthobothrium cimari n. sp, in D. longus, most similar to A., lili um, A. lineatum, A, himanturi, A. costarricense, and Acanthobothrium s emnovesiculum, has bothridial hooks averaging 117 mu m (lateral) and 1 21 mu m (medial) long, an average of 50 testes per proglottis, cirrus sacs averaging 164 mu m long, and asymmetrical ovarian lobes with pora l lobes reaching the posterior margin of the cirms sac, and aporal lob es reaching the level of the vagina. Acanthobothrium puntarenasense n. sp. in D. longus, distinctive in having a very small scolex relative to the width of the cephalic peduncle similar to Acanthobothrium micro cephalum, has bothridial hooks averaging 111 mu m (lateral) and 117 mu m (medial) long, an average of 50 testes per proglottis, cirrus sacs averaging 170 mu m long, and asymmetrical ovarian lobes with poral lob es reaching the posterior margin of the cirrus sac. and aporal lobes r eaching the middle of the cirms sac. Acanthobothrium vargasi in D. lon gus, most similar to Acanthobothrium brevissime, Acanthobothrium tasaj erasi, Acanthobothrium urotrygoni, and Acanthobothrium campbelli, has bothridial hooks averaging 130 mu m (lateral) and 133 mu m (medial) lo ng, an average of 25 testes per proglottis arranged in 2 single rows, cirms sacs averaging 91 mu m long, and asymmetrical ovarian lobes with poral lobes reaching the posterior margin of the cirms sac, and apora l lobes reaching the middle of the cirrus sac. Acanthobothrium campbel li n. sp. in Urotrygon chilensis, most similar to A. brevissime, A. va rgasi, A. lineatum, A. himanturi, and A. urotrygoni, has bothridial ho oks averaging 108 mu m (lateral) and 111 mu m (medial) long, an averag e of 19 testes per proglottis arranged in 2 nearly linear rows, cirms sacs averaging 74 mu m long, and asymmetrical ovarian lobes with the p oral lobe reaching the posterior margin of the cirrus sac, and the apo ral lobes reaching the middle of the cirms sac.