02786nas a2200337   4500008004100000022001400041245022500055210006900280260001300349300001100362490000700373520165800380653001902038653001202057653001102069653001802080653002602098653000902124653003502133653003902168653001802207653001502225653001802240653000902258100001802267700002502285700002302310700003302333700003202366856005002398       2009                        eng d  a1937-234500aRedescription of Rhadinorhynchus ornatus (Acanthocephala: Rhadinorhynchidae) from skipjack tuna, Katsuwonus pelamis, collected in the Pacific Ocean off South America, with special reference to new morphological features.0 aRedescription of Rhadinorhynchus ornatus Acanthocephala Rhadinor  c2009 Jun  a656-640 v953 a<p>Adults of Rhadinorhynchus ornatus Van Cleave, 1918 were collected from the small intestine of skipjack tuna, Katsuwonus pelamis (Linnaeus), in the high seas of the Pacific Ocean off the west coast of South America (new parasite locality record) and described using optical microscopy and a scanning electron microscope (SEM). Our specimens were somewhat comparable to those described from North America and Japan, but had more trunk spines. Definitive differences between the length and thickness of each of the dorsal and ventral proboscis hooks are noted for the first time, with most ventral middle hooks being relatively shorter and more robust than dorsal middle hooks. The SEM documented, for the first time, the different surface topography of the tegument in the proboscis, the neck, and in 3 trunk regions; the presence of microtrichs in the mid- and posterior trunk regions; the elevated base of trunk spines; the circular arrangement of basal proboscis hooks; the different morphology of all dorsal and ventral proboscis hooks and the striations of their surface; the ribbed surface topography of eggs; the elevated slit-like female gonopore; and the rimmed edge of the bursa. The presence of microtrichs on the tegumental surface is further supported by transmission electron microscopy studies. This is the first report of microtrichs in any species of Acanthocephala and the second report of striations in proboscis hooks. The geographical distribution of R. ornatus appears to correspond, at least in part, to that of its epipelagic primary host, K. pelamis, throughout the world in waters ranging in temperature from 14.7 to 30 C.</p>10aAcanthocephala10aAnimals10aFemale10aFish Diseases10aHelminthiasis, Animal10aMale10aMicroscopy, Electron, Scanning10aMicroscopy, Electron, Transmission10aPacific Ocean10aPrevalence10aSouth America10aTuna1 aAmin, Omar, M1 aHeckmann, Richard, A1 aRadwan, Nahla, A E1 aAnchundia, Johan, S Mantuano1 aAlcivar, Marcos, A Zambrano  uhttps://acanthocephala.myspecies.info/node/30