title: The life cycle of Sclerocollum saudii Al-Jahdali, 2010 (Acanthocephala: Palaeacanthocephala: Rhadinorhynchidae) in amphipod and fish hosts from the Red Sea.
abstract: The rhadinorhynchid Sclerocollum saudii Al-Jahdali, 2010 was found in the intestine of its type host, Siganus rivulatus Forsskål & Niebuhr, 1775, a siganid fish permanently resident in a lagoon within the mangrove swamps found on the Egyptian coast of the Gulf of Aqaba (between 28°7'N and 28°18'N). Larval forms of this acanthocephalan (acanthors, acanthellae and cystacanths) were only found in Megaluropus agilis Hoek, 1889 (Crustacea: Gammaridae), a benthic amphipod abundant on algae and seagrasses in the lagoon. So, this life cycle of S. saudii was elucidated under semi-natural conditions: embryonated eggs of S. saudii were directly ingested by the amphipod and hatched in its intestine; the released acanthor penetrated the intestinal epithelium in 12-18 h to reach the connective tissue serosa, where it remained for about 3 days, then penetrated the intestinal wall and remained attached to its outer surface for 4 days. It then detached and dropped free in the amphipod haemocoel and transformed into an oval acanthella, growing for 16 days to reach the cystacanth stage. The cystacanth at 46 days post-infection was infective to fish (excysted in its intestine as an active juvenile). Male and female juveniles reached maturity 17 and 23 days post-infection. Recently copulated females first appeared 26 days post-infection and all females seemed to be copulated at 28 days post-infection; partially and fully gravid females first appeared 31 and 35 days post-infection. Mature males and fully gravid females started to die off naturally 31 and 43 days post-infection and were totally expelled from the fish intestine by 42 and 52 days post-infection. The cycle was completed in 89 days and is similar to other known palaeacanthocephalan life cycles, but has its own characteristics.
authors.affiliation: Biological Sciences Department, Rabigh-Faculty of Science and Arts, King Abdulaziz University,PO Box 344,Rabigh21911,Saudi Arabia.
authors.forename: M O
authors.initials: MO
authors.lastname: Al-Jahdali
authors.affiliation: Biological Sciences Department, Rabigh-Faculty of Science and Arts, King Abdulaziz University,PO Box 344,Rabigh21911,Saudi Arabia.
authors.forename: R M El-Said
authors.initials: RM
authors.lastname: Hassanine
authors.affiliation: Biological Sciences Department, Rabigh-Faculty of Science and Arts, King Abdulaziz University,PO Box 344,Rabigh21911,Saudi Arabia.
authors.forename: H El-S
authors.initials: Hel-S
authors.lastname: Touliabah
mesh_terms: D000049:Acanthocephala / Q000502:physiology*; D033304:Amphipoda / Q000469:parasitology*; D000818:Animals; D005399:Fishes / Q000469:parasitology*; D041981:Gastrointestinal Tract / Q000469:parasitology; D019156:Indian Ocean; D008018:Life Cycle Stages