Rhabdias paraensis sp. nov.: a parasite of the lungs of Rhinella marina (Amphibia: Bufonidae) from Brazilian Amazonia

The nematode parasites of Rhinella marina include species of the genus Rhabdias (Rhabdiasidae: Rhabditoidea). The present study describes Rhabdias paraensis sp. nov., which parasitizes the lungs of R. marina in Brazilian Amazonia. Of the more than 70 known species of this genus, 18 are parasites of bufonids, of which, eight are Neotropical. The new species described here is similar to Rhabdias alabialis in the absence of lips is different by the presence of conspicuous cephalic papillae. We describe details of the four rows of pores, which are distributed equally along the whole of the length of the body and connected with hypodermal cells, using histology and scanning electron microscopy. Other histological aspects of the internal structure of this nematode are also described.

Ultrastructural description of Ceratomyxa microlepis sp. nov. (Phylum Myxozoa): a parasite infecting the gall bladder of Hemiodus microlepis, a freshwater teleost from the Amazon River

A new ceratomyxid parasite was examined for taxonomic identification, upon being found infecting the gall bladder of Hemiodus microlepis (Teleostei: Hemiodontidae), a freshwater teleost collected from the Amazon River, Brazil. Light and transmission electron microscopy revealed elongated crescent-shaped spores constituted by two asymmetrical shell valves united along a straight sutural line, each possessing a lateral projection. The spores body measured 5.2 ± 0.4 µm (n = 25) in length and 35.5 ± 0.9 µm (n = 25) in total thickness. The lateral projections were asymmetric, one measuring 18.1 ± 0.5 µm (n = 25) in thickness and the other measuring 17.5 ± 0.5 µm (n = 25) in thickness. Two equal-sized subspherical polar capsules measuring 2.2 ± 0.3 µm in diameter were located at the same level, each possessing a polar filament with 5-6 coils. The sporoplasm was binucleate. Considering the morphometric data analyzed from the microscopic observations, as well as the host species and its geographical location, this paper describes a new myxosporean species, herein named Ceratomyxa microlepis sp. nov.; therefore representing the first description of a freshwater ceratomyxid from the South American region.