Infraciliature and other morphological characteristics of Enchelyodon longikineta n. sp. (Ciliophora, Haptoria)

Abstract

In this study, the morphology of a new ciliate belonging to the genus Enchelyodon was investigated. The body is flask-shaped or broadly oval, with a rounded posterior end, a knob-like protrusion of the anterior end of the body, and a size in vivo of 160–195 × 90–130 μm. The somatic ciliature consists of about 89 longitudinal kineties made of monokinetids, three of which have short paired cilia, forming a dorsal brush which extends from the circumoral kinety nearly to the posterior end of the body. The circumoral kinety is composed of 64–96 dikinetids. The macronucleus is ribbon-shaped, long and folded. Many spherical micronuclei are scattered in the cytoplasm. There is a single posterior contractile vacuole. There are rod-shaped extrusomes of two size classes: type I, 2.6–4.1 μm long, and type II, 51–63 μm long, measured in vivo . In addition, (developing ?) extrusomes with a globular thickening in the middle are evident in silver-impregnated samples. This combination of features is not found in any of the previously described species, and thus the Turkish population is classified as a new species Enchelyodon longikineta n. sp. It differs from its nearest relatives E. armatus, E. elegans, E. longinucleatus, E. nodosus and E. trilineatus in one or more of the following features: the shape and size of the body, nuclear pattern, extrusomes, dorsal brush, contractility, number of somatic kineties.