[Show abstract][Hide abstract] ABSTRACT: Demidospermus annulus sp. nov. (Platyhelminthes, Monogenea, Ancyrocephalidae) is described from the gills of the catfish Parapimelodus valenciennis Lütken collected in Samborombón Bay, Argentina. The new species differs from all congeneric species mainly by the structure
of the accessory piece of the male copulatory organ, the sclerotized ring-shaped vaginal aperture and the dorsal bar articulation.
–catfish–Salado River–western Atlantic coast
[Show abstract][Hide abstract] ABSTRACT: Ligophorus saladensis n. sp. (Monogenea: Dactylogyridae) is described from the gills of the grey mullet Mugil platanus Günther collected in Samborombón Bay, Argentina. The new species differs from L. mugilinus Euzet & Suriano, 1977, L. mediterraneus Sarabeev, Balbuena & Euzet, 2005 and L. huitermpe Fernandez, 1987 by the morphology of the accessory piece of the male copulatory organ and mean values derived from measurements of the sclerotised hard-parts. This is the second report of monogeneans on M. platanus in the Southwestern Atlantic Ocean region and the first description of a species of Ligophorus Euzet & Suriano, 1977 from M. platanus. Some aspects of the speciation and host-specificity of Ligophorus spp. are discussed.
[Show abstract][Hide abstract] ABSTRACT: During surveys of parasites of the whitemouth croaker Micropogonias furnieri (Desmarest) and the mullet Mugil platanus Günther from Samborombón Bay, Argentina, Trichodina puytoraci, T. lepsii, T. jadranica, T. murmanica, Diparitella simplex and Trichodina scalensis sp. n. were morphologically studied. Taxonomic and morphometric data for these trichodinids based on dry silver nitrate-impregnated specimens are presented. This study is the first formal report of these trichodinids from the southwest Atlantic Ocean, and the description of a new species from M. platanus.
[Show abstract][Hide abstract] ABSTRACT: A new species of trichodinid, Trichodina marplatensis sp. n., found on the comb plates of the coastal ctenophore Mnemiopsis
mccradyi is described. Only three species were previously reported from coelenterates, i.e., Trichodina pediculus, T. zambeziensis and
T. ctenophorii. This new ciliate is compared with other similar congeners including T. ctenophorii because it was reported from the same
host. T. marplatensis differs from T. ctenophorii by having denticles with broad club-shaped blades and wide S-shaped rays, rather than
falcate blades and thin, straight rays. The denticles of T. marplatensis are not similarly shaped to those of other described trichodinids. The
new species is the first reported from a planktonic host in the Argentine Sea and the second species found associated with ctenophores.
[Show abstract][Hide abstract] ABSTRACT: The encapsulation is well-known in arthropods like a
common type of defense against parasites, pathogens
and other foreign objects. This cellular defense reaction
takes place in two stages: the recognition of the
foreignness by the haemocytes and the formation of the
capsule followed by melanization. On the other hand, the
encystement is a process widely recognized in digeneans
produced by the cistógens, cephalic and tegumental
glands of the cercariae and metacercariae. In the
metacercariae of the Microphallidae family in crustaceans
the distinction between encapsulation and encystment
could not always be clear and the observation of mixed
processes is common. In the present work the type of
reaction and the genesis of the process of cyst and
capsule formation of Microphallus szidati metacercariae
are analyzed from experimental infections in the second
intermediate host Palaemonetes argentinus with natural
emerged cercariae from the first intermediate host
Heleobia parchapei. The observed reactions were of
mixed type, with the presence of a multilaminar cyst
surrounding the parasite, covered by a cellular reaction
by hemocytes with the formation of a capsule-like
envelope around the encysted metacercariae.
[Show abstract][Hide abstract] ABSTRACT: The presence of Squalonchocotyle squali MacCallum 1931 parasite of Squalus acanthias Linneaus, 1758, is reported for the first time in the Atlantic coast of Argentina, previous descriptions by MacCallum (1931), Price (1942) y Dillon & Hargis (1968) were compared. The possibility of the monogenoidean parasite of S. acanthias, from the Falkland Islands, collected by Kuznetsova (1975) and cited as Squalonchocotyle sp being represenstative of S. squali is discussed. The geographical range of distribution of S. squali is increased, and its presence on the Southeast of the Atlantic Ocean is confirmed.