Exploration of a Niche Specific, a Rare Desmid (Zygnematophyceae, Charophyta) Species from India, Oocardium corbettensis sp. nov.

Corbett Tiger Reserve (CTR) is the first and oldest tiger reserve for biodiversity conservation, which is located in the ecologically significant Bhabar-Terai region, foothills of the Himalayas in the Nainital and Pauri district, Uttarakhand, India. However, because of popular wildlife tourism destination and increased tourism in the CTR has caused alterations in habitat structures leading to temporary or permanent habitat loss. During the algal exploration, the specimen was observed on the metamorphic rock of slow running stream from the reserve forest area. Worldwide desmids are known for their extraordinary ornamental structures and indicators of oligotrophic environments. In the present investigation, the epilithic desmid, Oocardium corbettensis sp. nov. has been observed and reported from the Western Himalayan ranges of Corbett Tiger Reserve, India for the first time from India. This unusual, minute desmid is described and assigned to the genus Oocardium and compared with similar species and varieties of the genus Oocardium. This taxon exhibits certain unique features such as undulated rough, thick cell wall with semi-cells semicircular and varied even in cell dimensions from all existing varieties and species of Oocardium. Based on the morphological variations, a new species Oocardium corbettensis sp. nov. was reported and named after Corbett Tiger Reserve, from where this desmid was collected. The physico-chemical analysis of the water body where O. corbettensis sp. nov. was found revealed slightly alkaline conditions, with a pH of 7.7, conductivity (88.57 µS cm–1), total dissolved solids (41.87 mg L–1), salinity (0.04‰), water temperature (15°C), dissolved oxygen (8.2 mg L–1), free CO2 (17.47 mg L–1), calcium (2.3 mg L–1), magnesium (2.3 mg L–1), total hardness (5.7 mg L–1), alkalinity (102 mg L–1), potassium (0.55 mg L–1), nitrate nitrogen (0.12 mg L–1), soluble reactive phosphorous (0.92 mg L–1), and ammonium nitrogen (0.18 mg L–1). Based on trophic status score of 1.6, the water quality of the study site was clean (oligotrophic status). Thus, Oocardium corbettensis sp. nov. can be considered as an oligotrophic species.