Studies on Indian Copepods 3. Nearchinotodelphys indicus, a new genus and species of Archinotodelphyid Copepod from Indian seas

Abstract

Hansen (1923) obtained from Phallusia obliqua (=Ascidia obliqua) an interesting species of copepod which he named Cyclopina phallusiae. Hansen himself was uncertain about the correct systematic position of this copepod, for a species of the genus Cyclopina was never known to live within the ascidian. Lang (1949) suggested the creation of a new family Archinotodelphyidae to receive C. phallusiae Hansen and a new species of copepod which he gathered from Pyura georgiana Mchlsn during the Swedish Antarctic Expedition. He placed the two species in two monotypic genera, Archinotodelphys to contain his own new species and Pararchinotodelphys to include C. phallusiae. This was a fitting arrangement in view of the important and far-fetching suggestions he had already made regarding the classification of copepods (Lang, 1948). IUg (1955) discovered a second species of Pararchinotodelphys from the branchial cavities of Styela partita caught off Marthas Vineyard, Massachusetts. He provided an excellent discussion regarding the systematic position of all the three species and that of Pseudocyclopina belgicae Giesbrecht which was considered as congeneric with Cyclopina phallusiae by Lindberg (1952). In fact Lang's account of his new family and the two genera contained therein were very short and it was IUg who enlarged our understanding of this group. Pararchinotodelphys phallusiae was obtained during the Danish Ingolf Expedition ; Lang obtained specimens of Archinotodelphys typicus from the Antarctic ; and IUg reported P. gurneyi from north-west Atlantic. The archinotodelphyid copepod described below is collected from the south-east coast of India and appears to require a new genus and species to accommodate it. The male is not known for any of the earlier species. In the present case a fair number of males and females have been obtained and efforts have been made to elucidate points of sexual dimorphism in this primitive family. In describing the various morphological characters I have mainly adopted the terminology suggested by Gooding (1957) with some alterations (Ummerkutty, 1960) There is no absolute agreement between the various investigators on the homology of the constituting parts of the cephalosomal appendages of the copepoda. The terms ' protopod', ' endopod ' and ' exopod' are used in this paper rather in a descriptive sense than to indicate any strict morphological origin. These terms have been employed not only to describe the constituting parts of the swimming legs but also for those of the cephalosomal appendages, of the adult animals.