Studies on Indian Copepods 4. Description of the female and a redescription of the male of Pseudodiaptomus ardjuna Brehm (Copepoda, Calanoida) with notes on the distribution and affinities of the species

Abstract

In 1953, Brehm described a new species of calanoid copepod, Pseudodiaptomus ardjuna from Salsette Island, Thana District, Bombay. He had at his disposal only two male specimens, one of which was damaged. However, he could rightly identify it as a new species of the genus Pseudodiaptomus Herrick and gave a brief description of the male. The female of this species has not so far been described and there is no subsequent report of the male itself from anywhere. This short paper is meant to give a full account of both male and female collected from the South-East coast of India, off Mandapam. The present study is based on the examination of numerous specimens obtained from the plankton hauls, in the Gulf of Mannar and the Palk Bay ; samples were also obtained from the saline creeks leading to the Central Marine Fisheries Research Station Experimental Fish Farm. No morphological differences were noticed between the three examples ; however, the present material differs in some details from the descriptions and diagrams given by Brehm for the specimens he collected from Bombay waters and these differences are discussed below. In describing the various parts of the body, I have adopted the terminology suggested byGooding (1957) with some modifications (Ummerkutty, 1960 & 1960 a). In presenting the ornamentation of the swimming legs Sewell's suggestion (1949) to differentiate spines by Roman and setae by Arabic numerals is adopted