A new species of Mesocoelium (Digenea: Mesocoeliidae) found in Rhinella marina (Amphibia: Bufonidae) from Brazilian Amazonia

Abstract

The family Mesocoeliidae Dollfus, 1929 (Digenea) is composed by parasites of the digestive organs of a number of amphibian and reptile species including R. marina. This family has two genera: Mesocoelium Odhner, 1910 and Pintneria Poche, 1907(Pojmanska 2008. This paper describes the morphological and molecular characteristics of a parasite of the genus Mesocoelium, which appear to be unique and have thus led us to propose a new species. The digestive tube of each toad was isolated in phosphate buffered solution pH 7.4 and analyzed for trematodes. For light microscopy analysis, 10 parasites were fixed with 2% glacial acetic acid, 3% formaldehyde, 95% ethanol 70º, dehydrated in increasing ethanol concentrations, stained in alcoholic chloridric carmine, bleached in methyl salicylate and mounted in Entellan TM . Illustrations were drawn with camera lucida attached to an Olympus BX41 microscope. Measurements are presented in millimetres, unless otherwise indicated, as means and standard deviations, with the range of values in parentheses. MATERIALS AND METHODS FourteenFor scanning electron microscopy (SEM), 20 specimens were fixed with 2.5% glutaraldehyde, post-fixed in 1% OsO 4 0.8% K 2 Fe (CN) 6 , gold sputtered and observed in a Jeol JSM-5310 scanning electron microscope.Molecular characterization of three parasites was based on complete SSU rDNA gene, which after DNA extraction through the ChargeSwitch gDNA Mini Tissue Kit (Invitrogen Life Technologies), was amplified in two overlapping fragments using the primers 18S-E/18S-A27 and 18S-8/cestode-6 according to Olson and Caira (1999). The polymerase chain reactions (PCRs) were carried out in 25 µL final volume, containing 5-10 ng of DNA, 50 mM KCl, 2 mM MgCl 2 , 10 mM Tris-HCl, 50 µM of each DNTP, 0.5 µM of each oligonucleotide and one unit of Taq DNA polymerase (Invitrogen). Reactions using the 18S-E/18S-A27 primers were denatured for 5 min at 95ºC followed by 35 cycles, 1 min thermal denaturing cycles at 94ºC, 1 min at 68ºC for annealing and 1 min extension at 72ºC, with a final 7 min extension at 72ºC. Reactions using the 18S-8/cestode-6 primers were amplified following the same procedure, except for annealing temperature of 64ºC. Amplicons were electrophoresed in a 1% agarose gel, excised and puri-

A new species of Kentropyxia Baker, 1982 parasitic in the small intestine of Osteocephalus taurinus Steindachner (Anura: Hylidae) from the Brazilian Eastern Amazon

“…Recently, SEM has been used to study parasites of Amazon amphibians (Santos et al, 2008;Santos et al, 2011;Melo et al, 2011;Nascimento et al, 2013;Silva et al, 2013;Gomes et al, 2013) and has proven its importance in adding new morphological data and confirmation of surface details that can be difficult to visualised by light microscopy.…”

Morphological characterization of Eustrongylides sp. larvae (Nematoda, Dioctophymatoidea) parasite of Rhinella marina (Amphibia: Bufonidae) from Eastern Amazonia

“…In the last six years, new taxa have been reported from this host (SANTOS et al, 2008(SANTOS et al, , 2011MELO et al, 2011;GOMES et al 2013) together with the first report of Ortleppascaris (SILVA et al, 2013a, b). This study adds yet another component to this helminth fauna, for the first time describing morphological aspects of second-stage larvae of Eustrongylides in R. marina from the Marajó Archipelago, Eastern Amazonia.…”

Choledocystus elegans (Digenea: Plagiorchiidae) of Leptodactylus paraensis (Amphibia: Leptodactylidae) from the Brazilian Amazon

“…These parasites are common to several other amphibian species from the Americas, such as hosts of the genera Rana (= Lithobates) Linnaeus, 1758; Pseudacris (= Hyla) Fitzinger, 1843; Rhinella (= Bufo) Fitzinger, 1826 and Leptodactylus Fitzinger, 1826, which belong to the order Anura, and the genus Chthonerpeton Peters, 1880, which belongs to the order Gimnophiona (RANKIN, 1944;DOBBIN, 1958;TRAVASSOS et al, 1969;RAZO-MENDIVIL & PÉREZ-PONCE DE LEÓN, 2011;GOMES et al, 2013;FERNANDES & KOHN, 2014;KUZMIN et al, 2016). Until now, there is no report of trematodes parasites from L. paraensis, the present study describes new host, new geographical occurrence and infection site of parasitism of Choledocystus elegans (Travassos, 1926) Ruiz & Leão (1942) and news morphological aspects for this species.…”