80 A comprehensive study of diversity and distribution of subaerial Chroococcales from Similipal Biosphere Reserve, Odisha S. Behera 1 , S. Bhakta 2Ψ , E. Sahu 3 and A.K. Bastia 4 1 Depatment of Botany, Maharaja Sri Ram Chandra Bhanj Deo University, Baripada-757003 2 Botanical Survey of India, Andaman and Nicobar Regional Centre, Port Blair - 744102 3 Department of Botany, S. R. College, Baliapal, Balasore- 756023 4 Department of Applied Microbiology, Fakir Mohan University, Balasore-756020 Plant Science Research 46 (1&2) : 80-85, 2024 Plant Science Research ISSN 0972-8546 ABSTRACT Article history: Received : 10 September 2024 Revised : 15 October 2024 Accepted : 7 November 2024 This study investigates the diversity and distribution of Chroococcales belonging to cyanobacteria were studied within the Similipal Biosphere Reserve, Odisha, which has rich biodiversity and unique ecosystems. The specimens were collected through regular sampling across various habitats, including freshwater streams, subaerial corticolousregions, and moist soils, identified using morphological techniques. A total of 13 species belonging to the order chroococcales were documented under four families and seven genera, with the dominant occurrence of Gloeocapsa (5), followed by Aphanocapsa (2), Chrococcidiopsis (2) and single species each from Syenechococcus, Synechocystis, Cyanosarcina and Pseudocapsa. The distribution of the taxa signified five new records to Odisha namely Synechococcus pevelekii, Aphanocapsa grevillei, Gloeocapsa violacea, Gloeocapsa alpine and Pseudocapsa dubia, which may serve as a baseline for future research and conservation strategies to preserve the unique cyanobacteria of the Biosphere Reserve. ARTICLE INFO Introduction Cyanobacteria could grow in any environment where little moisture and sunlight are available. They can also survive the most adverse conditions of deserts (Friedmann and Ocampo-Friedmann, 1984), hot springs (Sompong et al., 2005, Bhakta et al., 2016), and hypersaline ecosystems (Chorus and Bartram, 1999). Chroococcales are characterised by single-celled or colonial forms classified under Cyanoprokaryota. Similipal (21°28”-22°08”N, 86°04”-86°37”E) is the only biosphere reserve of Odisha, situated in the northeastern zones of the state, gets good precipitation from dews, frost, mist etc. Over and above all it receives more rain & thus itharbours, a significant diversity of cyanobacteria occurring in various forms, such as lithic (epilithic and hypolithic), corticolous, benthic, epixylic, epipelic and floating. Though the study of subaerial cyanobacteria is meagre, it’s baseline diversity has been reported from different parts of India for their habitats (Bhuyan et al., 2007, Saha et al., 2007; León–Tejera et al., 2011; Jeyachitra et al., 2013 and Bhuyan et al., 2023). Studies on the taxonomy and diversity of subaerial cyanobacteria are incomplete and limited due to the lack of exploration, seasonal collection and where light and air humidity are considered the most influential ecological factors on the growth and development. However, there are also a few reports on these aspects (Tirkey and Adhikary, 2005; Uher, 2007; Neustupa & Skaloud, 2010; Dey and Bastia, 2009, 2010; Farrukh, 2011; Sethi et al., 2012; Halder, 2018, Bhakta et al., 2014 and 2015). Subaerial algae in the form of soil crust received ample attention for their ecological significance in recent years (Rehakova, 2011; Dev et al., 2013; Saminathan, 2013; Kumar et al., 2016, 2019) Similipal Biosphere Reserve is an untapped area for the study of subaerial algae, and the present work is considered as a valuable information of cyanobacterial diversity from this unique ecosystem. © 2024 Orissa Botanical Society Keywords: Cyanobacteria Chroococcales New record Similipal Biosphere Reserve Odisha Ψ Corresponding author; Email: skmrbhakta@gmail.com