Acanthocephalans from Red Sea fishes. Family Cavisomidae Meyer, 1932: The seasonal cycle of Diplosentis nudus (Harada, 1938) Pichelin et Cribb, 2001 in a definitive fish host, and a comment on Sclerocollum Schmidt et Paperna, 1978

Abstract

AbstractSpecimens of the fishes Rastrelliger kanagurta (Scombridae) and Siganus luridus (Siganidae) were caught in the Red Sea off the coast of Sharm El-Sheikh, South Sinai, Egypt. R. kanagurta was parasitised by Diplosentis nudus (Harada, 1938) Pichelin et Cribb, 2001 (Acanthocephala, Cavisomidae), and S. luridus by Sclerocollum rubrimaris Schmidt et Paperna, 1978 (Acanthocephala, Cavisomidae). The infection of R. kanagurta was followed monthly for one year (from September, 2004 to August, 2005). As a result, the seasonal cycle of D. nudus in its definitive host is described herein for the first time. The cycle is well-defined and extends for about 11 months (from October to August); in October, new generation of D. nudus starts to appear in the intestine of R. kanagurta; during the winter, the juvenile worms continued their growth; during the spring, most of the worms attained maturity and the mature worms copulated; during the summer, the worms began to die off naturally prior to their elimination from the intestine of the host. Sclerocollum rubrimaris is redescribed and Sclerocollum Schmidt et Paperna, 1978 is retained as a valid genus within the Cavisomidae.