The seasonal abundance and production of Oithona nana (Copepoda:Cyclopoida) in Southampton Water

Recent studies indicate that Oithona spp. contribute significantlyto total copepod biomass. Little is known, however, about theirecological significance, particularly in the case of the estuarineOithona nana. A study comprising three sites within SouthamptonWater was conducted to evaluate the late-stage copepodite/adult(stages IV–VI) O. nana community, using 120-µm meshnets. Although present throughout the estuary, there was a strikingspatial gradient with O. nana most common in the upper estuary.A clear seasonal pattern was observed with O. nana as the mostabundant copepod species from late summer until early winter.It comprised 61% of all copepods recorded, with a biomass of757.22 mg C m^–3. Production estimates of O. nana werederived from the ‘instantaneous-growth’ approach,using appropriate growth equations. The estimated productionof O. nana ranged from 1.50 mg C m^–3 year^–1 withinthe lower estuary to 146.77 mg C m^–3 year^–1 in theupper estuary. In the upper estuary, this compares with productionrates of 187.47 mg C m^–3 year^–1 for all Acartiacongeners (excluding nauplii), the most common calanoid genus.Throughout the estuary, O. nana annual production represented18% of total copepod production clearly indicating that, atleast in the upper estuary, O. nana production may be directlycomparable with calanoid production.     

A new species of Oithona (Copepoda, Cyclopoida) from the neritic waters of Australia

A new species of Oithona predominating in the neritic watersof Australia is described. This species resembles three otherspecies of the genus, but has several unique characters in thefamily Oithonidae. The morphological and geographical relationshipsof this species with allied species are discussed.     

Oithona brevicornis Giesbrecht (Copepoda, Cyclopoida) in harborages of the northeastern part of the Black Sea shelf

Cyclopoid species Oithona brevicornis Giesbrecht, a new species for the Black Sea, was found in zooplankton samples collected in autumn of 2005 and 2006 in the Novorossiysk and Tuapse ports of the northeastern shelf of the Black Sea. This species is assumed to have gotten into the Balck Sea with the ballast waters of ships.     

On the foraging and feeding ability of Oithona davisae (Crustacea,Copepoda)

Growth experiments with macrophytes revealed anomalies in the growth and development of Najas intermedia. Further analyses showed that these anomalies were caused by differences between the male and female plants. To examine the gender-related differences, the results of two field experiments and a phenological monitoring programme were analysed. The field experiments were conducted in four different lakes in Southern Germany. Over the course of 2 years, eight different sediments were used to research the interaction between the gender and the growth of N. intermedia plants. The phenological monitoring programme, on the other hand, was focused on the development of three different populations of N. intermedia in three Southern German lakes. The results of the experiments revealed significant differences in the gender-related development: Depending on the environmental conditions, male plants grew between 20 and 40% faster than female plants. Additionally, the male plants developed flowers earlier in the vegetation period and died before the female plants. As a result, male and female plants coexisted in the same lake only for a short period of time. This might be a strategy to reduce the competitive pressure between the genders and to gain an advantage over rival species.     

Intertidal interstitial Halicyclops from the Brazilian coast (Copepoda: Cyclopoida)

H. tageae sp. n. and Halicyclops ytororoma sp. n. are described from the intertidal interstitial water of Brazilian beaches. H. tageae is distinguished from all congeneric species by the number of setae on legs 1–4 endopodite 2 (1, 1, 2, 2) and by possessing a reduced inner spine on the leg 5 exopodite. It shares with H. brevispinosus, H. pusillus and H. canui the spine formula 2, 3, 3, 3 on exopodite 3 of swimming legs 1–4. H. ytororoma closely resembles H. gauldi and differs from this species by having 4 setae on leg 1 endopodite 3; H. gauldi has 3 setae on this segment.This is the first record of Halicyclops from marine interstitial water in Brazil.     

The independence of the family Channaculinidae (Crustacea: Copepoda: Cyclopoida)

New family name Pillainidae Kazatchenko fam. nov. is suggested instead of family name Channaculinidae. The keys of the families and genera of fish parasitic copepods of suborder Cyclopoida are given.     

Siphonostomes (Copepoda -- Cyclopoida) from the Indian Ocean

Siphonostomes (Copepoda — Cyclopoida) from the InternationalIndian Ocean Expedition collections were studied. The groupwas represented by Pontoeciella abyssicola of family Pon-toeciellidaeand Ratania flava of family Rataniidae. This study has extendedthe distribution of both the species considerably, and includesthe first record of the male of P. abyssicola from the IndianOcean and of both species from the Bay of Bengal.     

Laboratory maintenance of Eucyclops serrulatus (Copepoda: Cyclopoida).

A simple method for culturing a freshwater copepod Eucyclops serrulatus is described. A flagellate Chilomonas paramecium serves as the food organism. Starting from a single, egg-bearing female collected in a pond, the copepod proliferated for at least 10 generations apparently with no adverse changes. The stock culture has been maintained with minimal effort for at least 19 months. The method is expected to make the copepod useful in the laboratory as an intermediate host of various parasitic helminths.     

Variability of morphological characteristics in <Emphasis Type="Italic">Oithona similis</Emphasis> (Copepoda: Cyclopoida) in the White Sea

The spatial variability of the body size and morphological structures of the planktonic copepod Oithona similis in the White Sea was studied. From north to south, there was a tendency for the male cephalothorax length to decrease. In moving from the central to the northern part of the sea and from the eastern to the western part, the relative antennule length in both sexes increased. The average body size of copepods was positively and the absolute (and relative) lengths of the antennules were negatively correlated with water salinity. The morphological variations have adaptive significance and are determined by environmental factors.     

Cyclopina (Copepoda, Cyclopoida) from Brazilian sandy beaches

Five new species of Cyclopina Claus are described and C. mediterranea Steuer is redescribed from Brazilian sandy beaches. Cyclopina curoli sp. n. can be very abundant in coarse sandy shows. It is related to C. laurentica Mocholls and C. crassisserosa Herbst with which it shares a similar structure of Leg 5 in the female. Cyclopina dorae sp. n. is most closely related to C. meditarranea Steuer. Cyclopina arenosa sp. n. and Cyclopina yutimaete sp. n. are reminiscent of C. pontica Monchenko, the only other species of Cyclopina that possess a 2-segmented endopod in leg 1. Cyclopina caissara sp. n. is distinguished from all other congeneric species by having a very reduced inner spine in the leg 5 exopod of both male and female. This species shares with C. schneideri Scott and C. schneideri and C. brevifurca Sars the 12–segmented antennule. Taxonomical problems related to C. schneideri and C. brevifurea are discussed. Cyclopina mediterranea Steuer, 1940 is recorded for the first time from the American continent.     

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.      

Psammic Procyclopina (Copepoda, Cyclopoida) from the coast of Brazil

Procyclopina polyarthra Herbst is redescribed and three new species, P. maricopeba, P. feiticeira and P. uguaipuku , are described from intertidal interstitial waters. Procyclopina is distinguished within the family by the enditic setation of the maxilliped 0,1,3,4, the 19-segmented antennule, and three elements in the leg 5 exopod of the female. Procyclopina has its distribution restricted to the coast of Säo Paulo, Brazil. Procyclopina maricopeba sp. n. is distinguished from P. polyarthra by the three-segmented leg 5 in the male and by the length: width ratio of the genital double somite in the female. Procyclopina feiticeira sp. n. is unique in the genus by lacking the inner seta on legs 14 exp-I, and by the incomplete fusion of genital (seventh thoracic) and first abdominal somites in the female. Procyclopina uguaipuku sp. n. is characterized by the antennulary armature, by the caudal ramus (much longer than wide), and by the position of the proximal seta of the leg 4 enp-2 which is set on a protuberance on the posterior face. Morphological characters of Procyclopina are compared with those of other cyclopinids.     

Cryptic species in Diacyclops bicuspidatus (Copepoda:Cyclopoida): evidence from crossbreeding studies

The problem of cryptic species in Diacyclops bicuspidatus was examined using interpopulation crosses of four populations collected from a: (1) permanent flood lake in Kiev, Ukraine, (2) temporary pool in Kiev, (3) permanent pond in St. Petersburg, Russia (1200 km to north from Kiev) and (4) lake in Crimea (1100 km south of Kiev). The only interpopulation crosses to exhibit fertility were those between the St. Petersburg population and each of the two Kiev populations. The crosses between the Kiev and Crimea populations, between the St. Petersburg and Crimea populations, and between the two Kiev populations were sterile, as evidenced by either nonviable eggs, empty egg membranes or incomplete copulations. The F₁ hybrids resulting from the St. Petersburg permanent pond X Kiev flood lake cross were fertile and produced mature F₂ offspring. Some data on development times of parental and hybrid lines are presented. The St. Petersburg parental line showed development times almost twice as long as those of the Kiev flood lake population when reared at 10 °C and 20 °C in the laboratory. The F₁ offspring of the cross between St. Petersburg females and Kiev floodlake males showed similar development times to females of the St. Petersburg parental lines at both temperatures. The F₂ hybrids also showed development times that approximated those of the St. Petersburg parental line. These crossbreeding studies suggest the presence of cryptic species in the D. bicuspidatus inhabiting ecologically different populations in many parts of its large holarctic range.     

Comparative feeding ecology of Tropocyclops prasinus mexicanus (Copepoda, Cyclopoida)

The herbivorous and carnivorous feeding biology of Tropocyclopsprasinus mexicanus, an especially small cyclopoid copepod, wasstudied under in situ food conditions in three different lakesand under experimentally augmented food supplies. The mass-specificfood uptake is compared to that of two larger species—Cyclopskolensis and Cyclops vicinus. Under in situ food conditions,T.p.mexicanus depended to a larger extent on algae than invertebrateprey and showed lower mass-specific ingestion rates than thetwo larger species. Daily mass-specific uptake rates for algaeranged between 10 and 24% of its body mass versus 0.7–7%for invertebrate prey. The larger species C.vicinus and C.kolensisingested a total dry mass equivalent to 106% or up to 143% oftheir body mass with algae contributing 66 and 81%. However,under enriched food availability, T.p.mexicanus is able to ingesta biomass equivalent to its body mass, with an algae (54%) andprey (40%) portion similar to that of the larger species. Bodysize appears to be an important factor for the relative importanceof algal versus invertebrate prey for cyclopoid copepods.     

Carnivorous and detritivorous feeding of Mesocyclops leuckarti Claus (Cyclopoida Copepoda)

Food preference of M. leuckarti was experimentally analysed in relation to different species of live and dead crustaceans. Also their possibility of using detritus from bottom sediments as a source of food was tested.It has been found that M. leuckarti readily feed on dead organisms, and detritus from bottom sediments is sufficient for their survival.On the basis of experimental results the feeding strategy of M. leuckarti in lakes is discussed. It seems that the availability of different species of live prey depends on the mode of their swimming and on their body cover, while the availability of dead prey depends only on the body cover. Detritus may be an important source of food, particularly when the live prey are scarce in the pelagic zone, or not easily available.     

Morfologia y taxonomia de los Mesocyclops (Crustacea: Copepoda: Cyclopoida) de Mexico

A fundamental review of all species and subspecies of Mesocyclopsencountered in the territory of Mexico, a biogeographical transitionzone where the Neotropical Region bounds the Nearctic Regionin the south. The book begins with a sketch of the history of     

Two new species of Paracyclops (Copepoda: Cyclopoida,Cyclopidae) from Africa

Paracyclops longispina n. sp. and Paracyclops altissimus n. sp. are described. New characters derived from detailed examination of body and limb ornamentation are used to differentiate them from other Paracyclops species. Paracyclops longispina n. sp. resembles Paracyclops fimbriatus (Fischer, 1853) and Paracyclops imminutus Kiefer, 1929. It differs from the former by the presence of a well-developed spinular row near the base of the inner setae on the antennal coxobasis in both sexes, and from the latter in the structure of the seminal receptacle and the position of the mid-distal spinular row on the posterior surface of the coxa of leg 1. Paracyclops altissimus n. sp. can be distinguished from other members of genus mainly by the structure of the seminal receptacle and leg 5. This revised version was published online in July 2006 with corrections to the Cover Date.