Trichodina myicola n. sp., a Peritrichous Ciliate from the Marine Bivalve Mya arenaria L.

Abstract

A new ciliate from the marine clam Mya arenaria is described and figured. The form is designated Trichodina myicola with specific characters as follows: Bell‐shaped to discoidal; length 31–86 microns; diam. 62–103 microns; diam. denticulate ring 29–46 microns; 26–36 denticles; diam. of basal disk 42–79 microns; adoral ciliary spiral performs slightly more than one turn; posterior ciliature in three closely applied, concentric tiers: an anterior circlet of marginal cilia, a middle circlet of overlapping membranelles, and a posterior circlet of inner cilia; macronucleus C‐shaped; micronucleus small, round, lying near outer curvature of left arm of macronucleus; large contractile vacuole present near end of left arm of macronucleus. Taxonomy in the genus Trichodina is discussed and outlined. Special attention is given to details of the oral ciliature. T. myicola is compared with other members of the genus. A checklist of Trichodina species is presented.