Free-Swimming Copepod Nauplii of Narragansett Bay with a Key to Their Identification

Abstract

Zooplankton surface samples were taken with a number 12 silk bolting cloth net towed by a Clark-Bumpus quantitative plankton sampler in Narragansett Bay for 12 months. The samples were collected twice weekly, except during December, January, and February, at night at one position in the West Passage of Narragansett Bay. Ten calanoid, three cyclopoid, and one harpacticoid species of free-swimming copepod nauplii were collected from July 1957 through June 1958. The structure and arrangement of elements of the caudal armatures of these copepod nauplii showed certain differences which were utilized to develop a key.

Morphology of the naupliar stages of some Oithona species (Copepoda: Cyclopoida) occurring in Toyama Bay, southern Japan Sea

“…The present study compared the morphology of Oithona nauplii with reference to previous studies, having the following specific objectives: 1-investigation of the seasonal abundances of Oithona adults and estimation of the abundance of Oithona nauplii when copepod nauplii attain high densities in Toyama Bay; 2-selection of species with a high density throughout the year, as we considered the nauplii of these species would be more abundant.3-comparison of the morphology of each naupliar stage of the Oithona species that may be abundant in Toyama Bay throughout the year; and 4-in the discussion, a comparison of the results of the present study with those obtained previously (Björnberg 1972, Faber 1966, Gibbons & Ogilvie 1933, Oberg 1906, Rao 1958 in order to establish a systematic method for the identification of the naupliar stages of Oithona species.…”

“…The morphological development of naupliar stages of Oithona species recorded as adults from Toyama Bay have been investigated in a number of previous studies (Björnberg 1972, Faber 1966, Gibbons & Ogilvie 1933, Goswami 1975, Haq 1965, Murphy 1923, Oberg 1906, Rao 1958, Uchima 1979. However, there have been no studies on the morphological characteristics of O. longispina or O. setigera nauplii.…”

Studies on the Phylogenetic Implications of Ontogenetic Features in the Poecilostome Nauplii (Copepoda : Cyclopoida)

“…No caudal process has been discovered so far in other copepods except for a few harpacticoids of the genera Longipedia and Microsetella (Gurney, 1930;Nicholls 1935;Lovegrove, 1956;Faber, 1966;Hirakawa, 1974;Diaz & Evans, 1983;Koga, 1984;Onbe, 1984). Though the nauplii of Euterpina have a round process at the caudal end, it is uncertain whether or not the structure is a true caudal process.…”

“…Though the nauplii of Euterpina have a round process at the caudal end, it is uncertain whether or not the structure is a true caudal process. In the nauplii of Longipedia, the process is very prominent, almost as long as the body, at least in the first nauplius stage (Gurney, 1930;Nicholls, 1935;Faber, 1966;Koga, 1984;Onbe, 1984) and never disappears in the naupliar development, except for L. weberi. In L. weberi, the process degenerates rapidly with stage and disappears completely by the fifth stage (Koga, op.…”

“…The third nauplius of Tegobomolochus renicolis (Izawa, 1986b) and proabbly the third and sixth nauplii of Hemicyclops adhaerens (Faber, 1966) have a pair of stout spines, instead of weak ones which are usually found in the other poecilostome cyclopoids. Presence of this pair of stout spines seems to be a characteristic feature shared between the nauplii of the third and later stages in the taeniacanthiform group and Clausidiidae (to which Hemicyclops belongs).…”