Descriptions of new Parentodinium ciliates in the family Parentodiniidae n. fam. from Hippopotamus amphibiusin comparison with some entodiniomorphs from horses and cattle

Abstract

Descriptions of Parentodinium ostrea Thurston & Noirot-Timothee, 1973 and P. africanum Thurston & Noirot-Timothee, 1973 are revised on the basis of observation by pyridinated silver carbonate impregnation. Two new species, Parentodinium pediculum n. sp. and P. lituus n. sp., are also described. Based on the presence of caudal lobes, P. ostrea is divided into three forms, f. ostrea Thurston & Noirot-Timothee, 1973, f. euostrea n. f., and f. ablobum n. f. and P. pediculum is divided into two forms, f. pediculum n. f. and f. dorsale n. f. Until now, Parentodinium has been included in the family Cycloposthiidae. Because of its characteristic arrangement of infraciliary bands, a new family Parentodiniidae is proposed. Parentodinium ciliates are compared with five entodiniomorphid ciliates, Bundleia postciliata, Blepharocorys valvata, and Cycloposthium bipalmatum from the intestine of horses and Entodinium simplexand Eudiplodinium maggii from the rumen of cattle. Parentodinium has characteristic features intermediate between other entodiniomorphid families in both general and infraciliary morphology. Parentodinium has an ovoidal body laterally compressed, an ovoidal macronucleus varying in location, a micronucleus adhering to various sides of the macronucleus, and a single contractile vacuole in a posterior ventral location. Parentodium ostrea, P. africanum and P. pediculum have a cytoproctal ciliary tuft. Parentodinium has a characteristic arrangement of infraciliary bands distinct from other entodiniomorphid ciliates. The adoral polybrachykinety completely encircles the circumference of the vestibular opening. There are several vestibular kineties extending along the dorsal wall of the tubular vestibulum. Paralabial kineties are located at the right ventral side of the adoral polybrachykinety. Cytoproctal kineties run inside the cytoproct.