Studies on the free-living protozoan fauna of estuaries in the coastal zone of Tamil Nadu, India Author Bindu, L. text Records of the Zoological Survey of India 2021 121 1 61 75 journal article 10.26515/rzsi/v121/i1/2021/141506 2581-8686 13186453 10. Centropyxis aculeata (Ehrenberg, 1838) Material examined : Mi-112, 2 ex. , Coleron estuary, 02.vii.2012 ; Mi-125, 7ex. , Kaliveli estuary, 05.vii.2012 ; Mi-130, 6 ex. , Kaliveli estuary, 06.i.2013 ; Mi-142, 6 ex. , Vellar estuary, 08.i.2013 ; Mi-147, 6 ex. , Vellar estuary, 20.vi.2013 ; Mi-152, 4ex. , Karaikkal estuary, 19.vi.2013 ; Mi-163, 4 ex. , Coleron estuary, 21.vi.2013 ; Mi-244, 3 ex. , Vellar estuary, 20.vii.2014 . Diagnosis : Test brown in colour, slightly compressed and encrusted with quartz crystals; fundus rounded and furnished with a few spines arranged in a single row; aperture semi-circular and eccentric; shell 97-158 µm in diameter. Distribution in India : Assam , Andhra Pradesh , Arunachal Pradesh , Chandigarh , Himachal Pradesh , Kerala (Nilgiri Biosphere Reserve), Manipur , Meghalaya , Mizoram , Nagaland , Rajasthan , Sikkim , Tamil Nadu , Tripura , West Bengal .