Ultrastructure of the spermatozoon of the digenean Lecithocladium excisum (Rudolphi, 1819) (Hemiuroidea: Hemiuridae), a parasite of marine teleosts in Senegal.

The present study describes the ultrastructure of the mature spermatozoon of Lecithocladium excisum (Rudolphi, 1819) (Digenea: Hemiuroidea: Hemiuridae) from the stomach of the marine teleost Scomber japonicus Houttuyn (Scombridae) captured in the Atlantic Ocean, off Dakar (Senegal). The ultrastructural organization of the spermatozoon of L. excisum follows the general model described in most digeneans.

Spermiogenesis and the spermatozoon ultrastructure of Robphildollfusium fractum (Digenea: Gyliauchenidae), an intestinal parasite of Sarpa salpa (Pisces: Teleostei).

Spermiogenesis in Robphildollfusium fractum begins with the formation of a differentiation zone containing: two centrioles, each bearing striated rootlets, nucleus, several mitochondria and an intercentriolar body constituted by seven electron-dense layers. The two centrioles originate two free flagella growing orthogonally to the median cytoplasmic process. Later, the free flagella rotate and undergo proximodistal fusion with the median cytoplasmic process.

Spermiogenesis and ultrastructure of the spermatozoon of Wardula capitellata (Digenea, Mesometridae), an intestinal parasite of the sparid teleost Sarpa salpa in Senegal.

The spermiogenesis process in Wardula capitellata begins with the formation of a differentiation zone containing two centrioles associated with striated rootlets and an intercentriolar body. Each centriole develops into a free flagellum orthogonal to a median cytoplasmic process. Later these flagella rotate and become parallel to the median cytoplasmic process, which already exhibits two electron-dense areas and spinelike bodies before its proximodistal fusion with the flagella.

Ultrastructural study of the male gamete of Pleurogonius truncatus Prudhoe, 1944 (Platyhelminthes, Digenea, Pronocephalidae) parasite of Eretmochelys imbricata (Linnaeus, 1766).

In Pronocephaloidea, the spermatozoa of only two species have been studied today. Because of this, we present in this work data concerning to a third specie, Pleurogonius truncatus Prudhoe, 1944. The mature spermatozoon of P.

Ultrastructural study of the spermatozoon of the digenean Enodiotrema reductum Looss, 1901 (Platyhelminthes, Plagiorchioidea, Plagiorchiidae), parasite of the green turtle Chelonia mydas (Linnaeus, 1758) in Senegal.

This study describes the ultrastructural organisation of the spermatozoon of a digenean Enodiotrema reductum (Pligiorchiida: Plagiorchiidae) from the green turtle Chelonia mydas (Linnaeus, 1758). This is the first report of E. reductum from Senegal.

Sandonella sandoni (Lynsdale, 1960), an enigmatic and morphologically unique cestode parasitic in the osteoglossiform fish Heterotis niloticus in Africa.

Sandonella sandoni (Lynsdale, 1960) is the type and only species of the Sandonellinae, a cestode subfamily of unclear phylogenetic position. It is redescribed here on the basis of a re-examination of its syntypes, voucher specimens from museum collections, and freshly collected material from the intestine of Heterotis niloticus (Osteoglossiformes: Arapaimidae) from Benin, Nigeria, Senegal, and the Sudan. The species possesses several unique morphological characters, such as (1) a vitellarium formed by 2 compact, but deeply lobulated, postovarian masses near the posterior margin of proglottids; (2) a scolex with a highly modified apical structure formed by 4 muscular retractile lappets; (3) a well-developed circular musculature, which is external to the inner longitudinal muscles; (4) a dilated, vesicle-like proximal part of the external sperm duct; (5) the unique morphology of the uterus and its development, which represents an intermediate form between the 2 basic types recognized in the Proteocephalidea; (6) the growth of eggs during their development within the uterus; and (7) the complex proglottization with intermingled smaller and larger (wider) proglottids.