Abstract
Two new species of the genus Jonesius Yamaguti, 1959 have been described from avian hosts in Karachi. Jonesius calumbae n.sp., from the pigeon Columba livia (Gmelen) is characterized by having elongated scolex with muscular rostellum provided with ten hooks, suckers rounded to oval, anteriorly armed with minute spines. Genital opening is unilateral, genital atrium sucker-like, inside the osmoregulatory canals, testes two, symmetrical, rounded to transversely elongate cirrus sac reaching slightly beyond the median field, internal seminal vesicle large, elongate, broad at the base, external seminal vesicle absent. Ovary relatively large, transversely elongate, submedian, more towards poral side, larger than testes, slightly bilobed in some proglotids, vitelline gland compact, small, dorsal to ovary, therefore hardly visible, seminal receptacle present, poterodorsal to ovary. Gravid segments were not present. Other new species J. karachiensis n.sp. from the duck Tadorna tadorna (Linn.) is characterized by having a flattened scolex and long rostellum with ten hooks. Suckers are large occupying the whole scolex region at the sides of the rostellum. Genital opening is unilateral, marginal, near the anterior border of proglottid, testes two, almost rounded, cirrus sac reaching the median field, internal seminal vesicle small, round, external seminal vesicle absent. Ovary is rounded to slightly irregular, relatively small, median to slightly submedian, vitelline gland compact very small, hardly visible, dorsal to ovary, seminal receptacle present but not prominent. Uterus is intervascular, transverse sac containing eggs. This is the first report of the genus Jonesius Yamaguti, 1959 from Pakistan.
