The combined effects of temperature and salinity on the survival of Euterpina acutifrons (Dana) (Copepoda, Harpacticoida) from the New Zealand and Brazilian coasts

The combined effects of temperature and salinity on the survivalof non ovigerous female Euterpina acutifrons from the south-easternNew Zealand and southern Brazilian coasts were studied. Sixsalinities (6, 20, 34, 48, 62 and 76 ) and five temperatures(5, 10, 15, 20 and 25°C) were used for New Zealand specimenswhile six temperatures (5, 10, 15, 20, 25 and 30°C) andthe same salinities were employed for the Brazilian specimens.The mortality data were analysed statistically using multipleregression techniques. Animals from New Zealand showed greatertolerance to cold, less to high temperatures and more resistanceto both high and low salinities than those from Brazil, Animalsfrom both areas were slightly more tolerant of low temperaturein high salinities and of high temperature in low salinities.These striking differences observed between New Zealand andBrazilian populations of E. acutifrons imply the existence ofdifferent physiological races in this species.     

Zoogeography and parallel level-bottom communities of the meiobenthic harpacticoida (Crustacea,Copepoda) of Bermuda

Summary Twenty nine harpacticoid copepods are new to Bermuda and significant changes are noted in the distribution records of several species. Six temporary groups are organized to separate the copepods on their apparent zoogeographical ranges: (1) cosmopolitan, (2) warm temperate-tropical, (3) North Atlantic, (4) North Atlantic-Mediterranean, (5) Endemic to Bermuda and (6) uncertain. These six artificial groups do not necessarily correspond to the standard zoogeographical provinces. Endemism of the Bermudian harpacticoids is similar to the rates reported and predicted for other fauna on North Atlantic Islands. Low endemic rates probably reflect changing environmental conditions during the late Pleistocene.Three distinct harpacticoid isocommunities are reported. The associations are similar to harpacticoid assemblages found in similar sediment types in different parts of the world. All three associations are in agreement with Thorson's (1957) concept of the parallel level-bottom community.Contribution No. 78 from the Center for Marine and Environmental Studies, Lehigh University, Bethlehem, Pa., U.S.A.-Contribution No. 467 from the Bermuda Biological Station, St. George's West, Bermuda.     

Percent composition of fatty acids in Tigriopus fulvus from rocky pools on the Ligurian coast (Copepoda harpacticoida)

The study concerns the Tigriopus fulvus specimens fatty acid composition, sampled in Ligurian coast rockpools from September 1980 to June 1981. By the study of frequency distribution it was observed that the fatty acid found in greater quantity was the palmitic one, followed by the palmitoleic, the oleic and stearic acids. Short and long chain fatty acids are less frequent. Investigation about each fatty acid concentration shows that the seasonal trends between males and females are different and the trend of some fatty acids (e.g. linolenic and stearic acid) is characteristic.     

Characteristics of the reproductive cycles and development times of Copidodiaptomus numidicus (Copepoda: Calanoida) and Acanthocyclops robustus (Copepoda: Cyclopoida)

The female reproductive cycles of the calanoid copepod Copidodiaptomus numidicus and the cyclopoid Acanthocyclops robustus were characterized by periodic changes in the oviducts. Females oscillated between a gravid and a non-gravid condition, and the whole cycle was strongly dependent on temperature. In both species, the maturation of new oocytes took place when the old egg sacs were still being carried, thus ensuring a rapid clutch succession. The embryonic and post-embryonic development duration of C.numidicus and A.robustus was investigated at five and four different temperatures, respectively. Embryonic development time was related to oviductal cycle duration at each temperature to estimate the minimum amount of non-ovigerous females expected under non-limiting mate and food conditions. Copidodiaptomus numidicus females spent 35-19% of the cycle without carrying eggs at 7-20C. Acanthocyclops robustus females spent 31-33% of the cycle without carrying eggs at the same temperature interval. Both naupliar and copepodid durations were inverse functions of temperature with nauplii developing at a faster rate than copepodids. In general, A.robustus showed reproductive advantage over C.numidicus due to a faster oviductal cycle and shorter embryonic and post-embryonic development times. However, the influence of food quality may be crucial. Acanthocyclops robustus copepodid development may lengthen well beyond the corresponding development stages of C.numidicus when growing only on algae. This retardation of development affects especially the later development stages of the cyclopoid.      

Temperature-dependent development and growth of Calanus sinicus (Copepoda: Calanoida) in the laboratory

The calanoid copepod Calanus sinicus was reared in the laboratory under excess food conditions, and its development and growth rates were measured at various temperatures. Egg development time (D_H, days) was dependent on temperature (T °C), and was expressed as D_H = 55.3 (T + 0.7)^–1.44. Post-embryonic development followed the equiproportional rule. The stage duration was short in NI and NII, but compensatingly longer in NIII. Between NIV and CII, it was nearly isochronal, and beyond CII, it tended to increase gradually. The time from egg to adult was expressed as D_CVI = 1258 (T + 0.7)^–1.44. The specific growth rate was also temperature-dependent and highest from CI to CIII, intermediate from NII to CI and from CIII to CV, and lowest from CV to CVI. The growth rates of C. sinicus are higher than those of co-occurring small copepods such as Paracalanus, Acartia and Microsetella.     

Achilaophonte maxima gen.n., spec.n., a new taxon of the Laophontidae (Copepoda,harpacticoida) from the high Antartic (Weddell Sea)

Male and female of a new genus and species of the family Laophontidae, Archilaophonte maxima, are described. The specimen was found in the high Antartic (Weddell Sea) and apprears to be the most primitive genus up to now within the superfamily Laophontoidea as defined by Huys (1990). Based on its setation of legs and mouth parts, however, it can be placed unequivocally into the family Laophontidae. Archilaophonte maxima gen. n. shows close affinities to the laophontid genus Esola Edwards 1891. Both genera form a monophyletic group which is interpreted here as the first and most primitive offshot in the evolution of the Laophontidae. The synapomorphies of the former lineage are the shape of the protopodite of the P1 and shape and setation of the female P5.     

Growth and development of Metridia pacifica (Copepoda: Calanoida) in the northern Gulf of Alaska

Juvenile growth and development rates for Metridia pacifica,one of the dominant larger copepods in the subarctic Pacific,were investigated from March through October of 2001–2004in the northern Gulf of Alaska. The relationship between prosomelength (PL, µm) and dry weight (DW, µg) was determined:log₁₀ DW = 3.29 x log₁₀ PL – 8.75. The stage durationsof copepodites ranged from 3 to 52.5 days but were 8–15days under optimal condition. Seasonally, growth rates increasedfrom March to October and typically ranged between 0.004 and0.285 day^–1, averaging 0.114 ± 0.007 day^–1(mean ± SE). After standardization to 5°C (Q₁₀ of2.7), growth rates averaged 0.083 ± 0.005 day^–1and were significantly correlated to chlorophyll a, with saturatedgrowth rates of 0.149 day^–1 for C1–C3, 0.102 day^–1for C4–C5 and 0.136 day^–1 for all stages combined.Measured juvenile growth rates were comparable with specificegg production rates in this species. The comparisons of ourrates in this study with those predicted by the global modelsof copepod growth rates suggested that further refinement ofthese models is required.     

Natural development time of Eodiaptomus japonicus (Copepoda: Calanoida) in Lake Biwa

Seasonal and ontogenetic changes in natural development timewere studied for Eodiaptomus japonicus in Lake Biwa in 1986and 1987. Wild individuals in a certain developmental stagewere collected, fed on natural food and examined until theyhad moulted twice. Natural development times fluctuated irrespectiveof temperature from May to October. Food deficiency delayeddevelopment in all feeding stages, and food availability probablydetermined natural development time. Serious food limitationraised mortality in copepodid stage I. In November developmentwas delayed even with enough food. The development of E.japonicuswas almost isochronal except for a short prefeeding naupliarstage I and a long copepodid stage V.     

Postembryonic development of Tisbe gracilis (T. Scott) (Copepoda, Harpacticoida)

All six naupliar and five copepodite stages of Tisbe gracilis (T. Scott, 1895) are described. A key for the identification of the nauplius stages is given. The oral appendages of all copepodite stages are described. Sexual dimorphism is visible from the copepodite IV stage on.     

Variations in the embryonic development times and hatching success of three Boeckella species (Copepoda: Calanoida)

Embryonic development times of Boeckella triarticulata, B. dilatata and B. hamata are compared. Two species, B. triarticulata and B. hamata had widely varying embryonic development times. Variable development times often resulted in greater hatching success.     

Molecular phylogeny of the Calanoida (Crustacea: Copepoda)

The order Calanoida includes some of the most successful planktonic groups in both marine and freshwater environments. Due to the morphological complexity of the taxonomic characters in this group, subdivision and phylogenies have been complex and problematic. This study establishes a multi-gene molecular phylogeny of the calanoid copepods based upon small (18S) and large (28S) subunits of nuclear ribosomal RNA genes and mitochondrial encoded cytochrome b and cytochrome c oxidase subunit-I genes, including 29 families from 7 superfamilies of the order. This analysis is more comprehensive than earlier studies in terms of number of families, range of molecular markers, and breadth of taxonomic levels resolved. Patterns of divergence of ribosomal RNA genes are shown to be significantly heterogeneous among superfamilies, providing a likely explanation for disparate results of previous studies. The multi-gene phylogeny recovers a monophyletic Calanoida, as well as the superfamilies Augaptiloidea, Centropagoidea, Bathypontioidea, Eucalanoidea, Spinocalanoidea and Clausocalanoidea. The phylogeny largely agrees with previously-published morphological phylogenies, including e.g., enlargement of the Bathypontioidea to include the Fosshageniidae.     

Effects of small-scale turbulence on development time and growth of Acartia grani (Copepoda: Calanoida)

To test the effects of small-scale turbulence on developmentand growth of marine copepods, a series of 10 1 labortory microcosmswere used to follow the development, under turbulent and calmconditions, of a cohort of Acartia grani, a common coastal planktoniccopepod of temperate zones Aside from possible indirect effectsdue to differences in food availability, turbulence significantlyshortened development times and modified growth rates Theseinfluences seem to vary throughout its life history, late naupliiand early copepodites being more affected.     

Distribution and biogeography of the Paradiaptominae (Copepoda: Calanoida: Diaptomidae)

The Paradiaptominae, a subfamily of the large Diaptomidae family, is a small group of freshwater calanoids of which 24 species in four genera have been described. They are endemic to Africa with the exception of four species, Metadiaptomus asiaticus (Asia and Mongolia), M. gauthieri (Africa and Madagascar), Paradiaptomus greeni (India and Sri Lanka) and Neolovenula alluaudi (Canary Islands, North Africa, Baltic and Mediterranean countries). The North African species Metadiaptomus chevreuxi extends its range into Iraq and Iran. The Paradiaptominae are widely distributed in semi-permanent water bodies in the drier areas of Africa although most individual species have a restricted distribution. Only a few species have the ability to colonise permanent waters and these species are usually located at higher altitudes. The Paradiaptominae have not been recorded from the wet equatorial lowland areas of Africa. It seems likely that they are Gondwanian in origin as evidenced by their distribution (Africa, Madagascar, India and Sri Lanka). Neolovenula alluaudi (Mediterranean) shares morphological characters tenuously linked to the other species in the group and may either have a different origin or have branched off at an early stage in evolution of the group.     

Three Monstrilloids (Copepoda: Monstrilloida) From the Arctic

Three species of monstrilloids were collected in the plankton beneath the ice in December at Resolute Bay, Cornwallis Island in the Canadian Arctic. The species are determined as Monstrilla arctica n. sp., M. nasuta n. sp. and M. bernardensis (WILLEY, 1920). They are described and figured in detail.     

Postembryonic development of Phyllodiaptomus blanci (Guerne & Richard, 1896) (Copepoda,Calanoida)

All the postembryonic developmental instars of Phyllodiaptomus blanci (Guerne & Richard, 1896), reared in the laboratory, are described and illustrated. The larval affinities of this species vis-a-vis certain other diaptomid species are mentioned.     

Monstrilloida (Copepoda) off the Brazilian coast

Seven monstrilloid species of the genera Thaumaleus and Monstrilla (Copepoda) are reported from the Brazilian coast. Occurrence, distribution and ecological information is given for: T. longispinosum, T. rigidum, T. quadridens, M. recticulata, M. grandis, M. dubia and M. rugosa.     

The complete postembryonic development of Tropodiaptomus informis Kiefer, 1936 (Copepoda:Calanoida) reared in the laboratory

The complete postembryonic development of Tropodiaptomus informiscomprises six naupliar and six copepodid stages of which thelast is the adult. Of all the characteristics, it is the shapeand number of setae on the terminal segments of the antennulesin the late naupliar stages, and the shape and setae of exo-and endopods of the fifth legs from copepodids III to V whichare most useful in constructing relationships among eight diaptomidsreared.