Four new species of Hysterocinetida (Protozoa: Ciliophora) from the digestive tract of earthworms collected to the lower Nyong estuary (South Coast, Cameroon).

Hysterocinetida are a large assemblage of ciliates characterized by sucker and buccal apparatus. They have a wide distribution in the digestive tract of oligochaete annelids of the genus Alma that inhabit hydromorphic parts of non-anthropic hydrosystems. On the basis of morphological, morphometric and infraciliature characteristics revealed by ammoniacal silver carbonate and 4',6-Diamidino-2-Phenyl Indole (DAPI) staining techniques, four forms were identified as new members belonging to three genera: Preptychostomum, Proptychostomum and Thurstonia. Preptychostomum donendaensis n. sp. is ovoid with a slightly narrowed anterior part and is commensal to the digestive tract of Alma emini and A. nilotica. There are 20-23 kineties on the lower side and 42-45 on the upper side. Proptychostomum gigas n. sp. is pear-shaped, with a narrowed anterior part and a wide posterior part (125-138 µm × 80-85 µm). There are 40 to 44 kineties, equally distributed on both sides of the ciliate. Its sucker is circular and measures 31-34 µm in diameter. The peristome follows the contour of the cell and the infundibulum has a turn of spire. Thurstonia emini n. sp. is identified in the digestive tract of A. emini. The cell is elongate, with the anterior pole narrower than the truncate posterior pole (90-115 µm × 40-55 µm). The kineties are equally distributed on both sides of the ciliate. The sucker is in the shape of an inverted U. Thurtonia nilotica n. sp. is commensal of the digestive tract of A. nilotica. The cell is pear-shaped, with the anterior part narrowed and the posterior part swollen (110-114 µm × 85-92 µm). 46 to 50 kineties are unevenly distributed on both sides of the ciliate. The sucker is shaped like an inverted lunar crescent.

Morphology and infraciliature of two new earthworm ciliates, Hoplitophrya polymorphus sp. nov. and Anoplophrya simplex sp. nov. (Ciliophora: Oligohymenophorea: Astomatia).

Morphological and infraciliature studies carried out using pyridinated ammoniacal silver carbonate and the 4',6-diamidino-2-phenylindole (DAPI) staining techniques, led to the identification of two new species of ciliates pertaining to the subclass Astomatia. The first species, Hoplitophrya polymorphus sp. nov., displays two main cellular forms: the elongated form (150-247 µm long and 40-87 µm width) and the stocky form (140-170 µm long and 70-98 µm width). The macronucleus is generally skinny in the elongated forms and ribbon-shaped in the stocky forms. The common feature of the two cellular shapes uniting them in the same species is the identical structure of their skeletal apparatus, a V-shaped element located in an apical depression and bearing skeletal fibres on its ventral face. The second species, Anoplophrya simplex sp. nov., is totally deprived of skeletal apparatus. The cell shape is fusiform and dorsoventrally flattened (105-180 µm long and 65-125 µm width). Six to 12 pulsatile vacuoles form two rows arranged symmetrically on either side of the macronucleus. These two newly identified species highlight the extremely rich diversity of ciliates inhabiting the digestive tract of tropical earthworms.

Genetic diversity and phylogenetic position of the subclass Astomatia (Ciliophora) based on a sampling of six genera from West African oligochaetes (Glossoscolecidae, Megascolecidae), including description of the new genus Paraclausilocola n. gen.

To more confidently assess phylogenetic relationships among astome ciliates, we obtained small subunit (SSU) rRNA sequences from nine species distributed in six genera and three families: Almophrya bivacuolata, Eudrilophrya complanata, Metaracoelophrya sp. 1, Metaracoelophrya sp. 2, Metaracoelophrya intermedia, Metaradiophrya sp., Njinella prolifera, Paraclausilocola constricta n. gen., n. sp., and Paraclausilocola elongata n. sp. The two new species in the proposed new clausilocolid genus Paraclausilocola n. gen. are astomes with no attachment apparatus, two files of contractile vacuoles, and an arc-like anterior suture that has differentiations of thigmotactic ciliature on the anterior ends of the left kineties of the upper surface. Phylogenetic analyses were undertaken using neighbor-joining, Bayesian inference, maximum likelihood, and maximum parsimony. The nine species of astomes formed a strongly supported clade, showing the subclass Astomatia to be monophyletic and a weakly supported sister clade to the scuticociliates. There were two strongly supported clades within the astomes. However, genera assigned to the same family were found in different clades, and genera assigned to the same order were found in both clades. Thus, astome taxa appear to be paraphyletic when morphology is used to assign species to genera.