Morphological identification of the marine cyclopoid copepod Dioithona rigida in combination with sequencing a 645 bp fragment of mitochondrial cytochrome oxidase c subunit I (mtCOI) gene, collected from offshore waters of Kavarathi Island, Lakshadweep Sea, is presented in this study. Kiefer in 1935 classified Dioithona as a separate genus from Oithona. The main distinguishing characters observed in the collected samples, such as the presence of well-developed P5 with 2 setae, 5 segmented urosome, 12 segmented antennule, compact dagger-like setae on the inner margin of proximal segment of exopod ramus in P1-P4 and engorged portion of P1-bearing a spine, confirmed their morphology to D. rigida. A comparison of setal formulae of the exopod and endopod of D. rigida with those recorded previously by various authors are also presented here. Maximum likelihood Tree analysis exhibited the clustering of D. rigida sequences into a single clade (accession numbers KP972540.1-KR528588.1), which in contrast was 37-42% divergent from other Oithona species. Further intra-specific divergence values of 0-2% also confirmed the genetic identity of D. rigida species. Paracyclopina nana was selected as an out group displayed a diverged array. The present results distinctly differentiated D. rigida from other Oithona species.
Lakshadweep archipelago is a group of coral Islands on the West coast of the Arabian Sea. It is one among the unique coral atolls in India that are well known for several species of fishes and other biotic resources. Seasonal variation in mesozooplankton, particularly of copepod abundance and distribution in the inner and outer lagoon of Kavaratti atoll were studied during April 2013 (premonsoon), September 2013 (monsoon) and January 2014 (postmonsoon). Copepods were the most dominant taxa in all the stations and seasons, that accounted 44.15 to 85.97% of the total mesozooplankton abundance. Ostracoda (premonsoon), crustacean larvae (monsoon) and chaetognaths (postmonsoon) formed the abundant groups in the respective seasons. Mesozooplankton community in the study area exhibits temporal variation corresponding to the variation in abiotic parameters therefore can be used as potential indicators of water quality. Calanoid copepods formed the dominant taxa during monsoon and postmonsoon, while cyclopoid copepods dominated during premonsoon. Among the copepods, species of the family Candacidae, Calanidae, Pontellidae, Temoridae, Psuedodiaptomidae, Centropagidae and Oithonidae were predominant. The ten species of calanoids were previously not reported from Kavaratti atoll, in Lakshadweep.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.