Two freshwater flagellates from the Mahananda Wildlife Sanctuary, West Bengal Author Bharti, Daizy Author Kumar, Santosh text Records of the Zoological Survey of India 2019 119 4 451 455 journal article 300567 10.26515/rzsi/v119/i4/2019/142050 8778a460-a9d4-4e44-8436-74394fffc11d 2581-8686 13185914 1. Rhabdomonas costata (Korshikov) Pringsheim, 1942 ( Figure 1 A-E) Diagnosis of the Indian population (Data based on 7 specimens ): Size about 20 × 10 μm in stained preparations; shape elliptical to narrowly elliptical, longitudinally extended, abdominal side convex,dorsal slightly curved.Nucleus slightly posterior of body midline, about 6-11 μm from anterior body end with diameter about 4-5 μm, nucleolus globular visible in stained preparation with diameter about 3-4 μm. Paramylon bodies of 2-5 μm length present throughout the cell. A row (sometime two rows) of ejectosomes present posterior to the base of flagellum.Two flagella emerging out from a prominent small groove at the anterior body end, one flagellum slightly shorter than the other. Material deposited: A slide including protargolimpregnated specimens have been deposited at the National Zoological Collections of the Zoological Survey of India , Kolkata, India with the following accession numbers Pt. 4506 (specimens marked with black ink circles on the slide). Occurrence and ecology : The species Rhabdomonas costata is rather common in both freshwater ecosystems. It has a rather cosmopolitan distribution with reports from Europe, Poland , Asia, and North America. The present study reports its presence from a small pond near Helay Khola watch tower, Lower Ghoramara Block, Sevok Beat, North Range, Mahananda Wildlife Sanctuary, West Bengal (26°50'671"N 88°26'293"E). When the sample was collected the specimens were in high abundance and possibly responsible for the slightly greenish colour of the water due to its blooming.