Rigidohymena quadrinucleata ( Dragesco and Njiné, 1971 ) Berger, 2011

Ghosh, Subhadeep, Ghosh, Arnab, Bharti, Daizy & Kumar, Santosh, 2022, Four New Records of Ciliated Protists from Lakshadweep, India, Records of the Zoological Survey of India 122 (3), pp. 291-298 : 292

1. Rigidohymena quadrinucleata ( Dragesco and Njiné, 1971) Berger, 2011 ( Figure 1 A-G)

Brief description of the Indian population (based on four specimens from live and seven from protargol impregnation): Size about 110 × 55 μm in protargol preparations; shape elliptical with body ends rounded; dorsoventrally flattened. Nuclear apparatus with four macronuclear nodules in or slightly left of the body’s midline. Contractile vacuole near the left cell margin. Cortex rigid; cytoplasmic crystals of usual shapes. Buccal cavity: deep and wide; undulating membranes in Cyrtohymena -pattern, optically intersecting at the posterior third near the buccal vertex. The adoral zone occupies about 50% of the body’s length and is composed of 37 membranelles. On average, there are three frontal cirri, one buccal cirrus, four fronto-ventral cirri arranged in a hook-shaped pattern, three post-oral ventral cirri, two pretransverse ventral cirri, and five transverse cirri. One left and right marginal cirral row, each with 16 cirri. Six dorsal kineties, including two dorsomarginal rows. Invariably, three caudal cirri are at the posterior end of dorsal kineties, 1, 2, and 4.

Material deposited: Five slides with protargolimpregnated specimens have been deposited at the National Zoological Collections of the Zoological Survey of India, Kolkata, India, with the following accession numbers: Pt. 5172, Pt 5236, Pt 5237, Pt 5238, and Pt 5243.

Occurrence and ecology: Thus far, reported from Yaounde, Cameroon; Salzburg, Austria; Namibia; Antarctica; Brazil; China, Slovakia ( Dragesco and Njiné 1971; Njiné, 1977; Foissner 1984, 1997; Wang et al., 2017; Benčaťová and Tirjaková 2017). The Indian population was isolated from soil sample collected from Minicoy Island, Lakshadweep, India (8°16’13.6”N 73°01’59.3”E). Typically feeds on algae and small ciliates.

Genus Oxytricha Bory de St. Vincent in Lamouroux, Bory de St. Vincent and Deslongchamps, 1824

Figures

Figure 1. Photomicrographs of live (A, B) and protargol impregnated (C-G) specimens of Rigidohymena quadrinucleata Indian population. A, B. Specimens showing the body shape and position of contractile vacuole. C. Specimen showing ciliature on the ventral surface. D,F. Specimen showing dorsal kineties and caudal cirri (D). E. Details of the oral apparatus, showing distinct Cyrtohymena-like buccal field. G. Arrangement of four macronuclear nodules. AZM, adoral zone membranelles; DK1, dorsal kinety 1; DM, dorsomarginal kinety; E - Endoral; FC - Frontal Cirri; LM - Left Marginal cirral row; Ma - Macronuclear nodules; P - Paroral; RM - Right Marginal row; TC - Transverse Cirri. Scale bars: 50 μm (A, B), 30 μm (C-F).