ABSTRACT

A new trematode genus Neoeneuterum has been described from the intestine of fish, Thynnus thunnia, of the Karachi coast. The species was named N. mineutum. The new genus is characterized by having small, smooth, flattened and elongated body, a mouth surrounded by 6 delicate papilliform extensions, a prominent oral sucker, a conspicuous pre-pharynx, a moderately developed pharynx, an esophagus almost as long as the pre-pharynx, and long ceca not joined posteriorly. The acetabulum is in the anterior half of the body and is larger than the oral sucker. There are 2 testes that are soft and close together in the posterior quarter of the body. The cirrus pouch is large extending to posterior region and an external seminal vesicle is present. There is a preacetabular genital pore surrounded by a glandular area. The ovary is in front of the testicles, a seminal receptacle is present, and the vitelline follicles are large extending post-acetabular rejoining laterally to the posterior extremities of the body. The excretory vesicle is tubular. The new genus is included in the subfamily Enenterinae of the family Opecoeliidae but shows some important diagnostic variations, therefore, the subfamily evaluation has been amended to accommodate the new genus. The genus name shows its relation to the subfamily and the species name refers to its small size.

Keywords: Neoeneuterum minutum, new genus, Trematoda, Opecaeliidae, Enenterinae, Thynnus thunnia, Karachi Coast