On nine Tropodiaptomus-species (Copepoda,Calanoida) from equatorial East Africa

Of the nine species of Tropodiaptomus occurring in Equatorial East Africa, seven are redescribed and figured in great detail. Their relationships are discussed. A primary homonym is eliminated, and types are indicated wherever possible.     

Taxonomy of the genus Megacyclops (Crustacea,Copepoda): morphometry and the use of enzyme electrophoresis

Morphometric investigations on the populations of Megacyclops in Lake Constance showed, that in a sublittoral region from about 20 to 50 m depth an intermediate type between the two species M. viridis (littoral) and M. gigas (benthal) could be distinguished. Using enzyme electrophoresis it was evident, that these specimens belonged to M. viridis.The annual range of water temperatures in the sub-littoral region corresponds to that found in the shallow areas of the lake or in ponds during winter and early spring, when the adults of M. viridis are markedly larger than in summer and fall (seasonal variation). Nevertheless the sublittoral population represents a different local type with special characteristics in morphometric details.     

The biogeography of three Boeckella species (Copepoda: Calanoida) in New Zealand

The New Zealand distributions of three species of Boeckella (Copepoda, Calanoida), B. triarticulata, B. dilatata and B. hamata are mapped. B. triarticulata is primarily a pond dweller but is also found in reservoirs and shallow lakes. B. dilatata is mainly found in the deeper glacial lakes and ponds in the central region of the South Island and B. hamata has a more widespread distribution in lakes and ponds in the South Island and lower half of the North Island. Differences in temperature optima, food requirements and dispersal ability among the three Boeckella species are related to vicariant events to explain their distribution in New Zealand.     

Development of Acartia clausi (Copepoda,Calanoida) cultured at different conditions of temperature and food

The pelagic copepod Acartia clausi Giesbrecht was bred 3 times from nauplius stages I and II to maturity at 5, 10, 15 and 20 °C and 4 different rations of autotrophic and heterotrophic food. The rate of development of copepods increased with increasing temperature and food level. At the highest food level the stage duration was almost constant through most stages, but development was not quite isochronal. Particularly at lower food concentrations stage duration became progressively longer with increasing stage of development. The relation between development time and temperature is described by Blehrádek's functions at different food levels. These relations predict a generation time of about 50 days at spring bloom conditions and only slightly less during summer due to food limitation. Comparison with estimates in the field from the literature suggests hat food is often limiting during summer conditions.     

Age, distribution and abundance of viable resting eggs of Acartia pacifica (Copepoda: Calanoida) in Xiamen Bay, China

The distribution and abundance of viable resting eggs of copepod Acartia pacifica in Xiamen Bay, China, were determined in the laboratory by the presence of nauplii hatched from the sediments. Sediment cores to a depth of 30 cm, sliced at 1.0 cm intervals, showed that most viable resting eggs of A. pacifica occurred near the sediment surface (0-5 cm), and the number of viable eggs sharply decreased with depth of the sediment, although resting eggs remained viable as deep as 23 cm. ²¹⁰Pb analyses of the sediments indicated that the maximum age of viable eggs of A. pacifica was 20.5 years and the mean egg age was 4.3 years. The egg mortality of A. pacifica in the sediment was 0.1408 year⁻¹, or 85.92% annual egg survival, calculated by regressing ln(egg density) on the age of the sediment. The horizontal distribution of viable resting eggs ranged from 2.27×10³ to 3.85×10⁵ m⁻², with a mean value of 9.49×10⁴ m⁻². Regressions between viable eggs of A. pacifica and all fine-fraction particle size classes (at 2 μm intervals) were not significant. The accumulation of viable resting eggs that can persist for an extended period of time provided evidence for the existence of an egg bank of A. pacifica in the seabed of Xiamen Bay.     

Ryocalanus spinifrons,a new species of Ryocalanidae (Copepoda: Calanoida), from the southwestern part of Sagami Bay,Japan

A new Ryocalanoid copepod, Ryocalanus spinifrons, collected by the MTD net system at a depth of 1400 m from the southwestern part of Sagami Bay, Japan, is described. The new species is morphologically very close to R. infelix Tanaka, 1956 (female unknown) from the Izu region of Sagami Bay. It is distinguished from other species by the presence of 12 long spinules on the ventral inner side of the fifth pedigerous somite, nine setae on the coxal epipodite of the maxillule and nine large robust spinules on the coxal segment of the fourth leg. The row of five robust spines on the paragnath distinguishes R. spinifrons.     

The identification of Pomatoschistus minutus (Pallas) and Pomatoschistus lozanoi (de Buen) (Pisces, Gobiidae)

Sand gobies areextremely abundant in coastal waters and estuaries. Pomuroschistus lozunoi tends to be overlooked due to identification problems. This paper summarizes the characteristics to distinguish P. lozanoi from P. minutus and presents a new distinctive feature that allows identification of juveniles from 15-20 mm standard length onward. The known geographic distribution of P. lozanoi is extended northward to 53°30' N and southward to 40°N on the coast of Europe. In northern Europe P. loxmoi seems better adapted to the estuarine habitat than previously thought.     

The distribution of brackish water Calanoida (Copepoda) along the coasts of Brazil

The distribution of 18 species of Calanoida Copepoda found in the estuaries of the Brazilian coast is analyzed. A slight tendency of a latitudinal decrease in diversity, from North to South is found. Salinity ranges from the different species are discussed and in some cases interspecific vicariance patterns are found. Two basic types of estuaries of the Brazilian coast are characterized on the basis of environmental parameters and population dynamics.     

On Gaussia Wolfenden (Copepoda,Calanoida, Metridinidae)

Aspects of the female genital segment with and without attached couplers and enclosed spermatophores are studied of Gaussia specimens collected in the SW Atlantic and SE Pacific. A new species found in the SW Atlantic, Gaussia asymmetrica, is proposed.     

Redescription and distribution of Boeckella gibbosa (Brehm, 1935) (Copepoda,Calanoida, Centropagidae)

Thirty-five species of the family Lecanidae are examined from Tripura state in North-Eastern India. Of these, Lecane levistyla and L. scutata are interesting cold-water forms; L. batillifer is an Australasian element; L. acanthinula and L. sinuata are Oriental endemics and L. braumi, L. lateralis and L. simonneae are palaeotropical species. The lecanid fauna also includes the pantropical L. thienemanni and L. sola while the remainder are cosmopolitan and tropicopolitan elements. This revised version was published online in August 2006 with corrections to the Cover Date.     

Eudiaptomus anatolicus n.sp. (Copepoda: Calanoida) from Turkey

Eudiaptomus anatolicus n.sp. displays similarity to E. transylvanicus (Daday, 1890) by possessing an outer marginal spine located proximally on the second exopodite segment of the male right P₅, but it differs from this closest species in the presence of a chitinous projection on the second exopodite segment of the male right P₅, and in the typical shape of the female's thoracic wings. E. transylvanicus (Daday, 1890) has three chitinous processes located on the basipodite segment of the male right P₅, whereas Eudiaptomus anatolicus n.sp. has only one small process on this part. This new species is living in lake Poyraz, which is small and shallow. Some cladoceran species, namely, Pleuroxus truncatus (O.F. Müller, 1785), Pleuroxus laevis (Sars, 1862), Pleuroxus trigonellus (O.F. Müller, 1785), Simocephalus exspinosus (Koch, 1841), Eurycercus lamellatus (O.F. Müller, 1785), Alonella excisa (Fischer, 1854), Lathonura rectirostris (O.F. Müller, 1785), Pseudochydorus globosus (Baird, 1843) and two cyclopoid copepods, Megacyclops viridis (Jurine, 1820) and Eucyclops serrulatus (Fischer, 1851) share the same habitat. This revised version was published online in July 2006 with corrections to the Cover Date.     

On the taxonomy of the genus Megadiaptomus Kiefer,including the description of a new species (Copepoda,Calanoida) from India

The insecticide permethrin (a synthetic pyrethroid) was applied into enclosures (1 m diameter and 3.5 m deep) placed in a pond. The chemical was rapidly removed from the water to the sediments. Daphnia rosea and its predator, Chaoborus flavicans were seriously affected by this application and disappeared from the enclosure. Acanthodiaptomus pacificus increased as Chaoborus decreased. Two species of Cladocera which had not been observed before the treatment, established their populations after 10 days, when Chaoborus had not recovered. Whereas Tropocyclops pracinus declined when permethrin was applied at 10 µg 1^–1, the number of rotifer Keratella valga increased, suggesting a close relationship between these two species.Photosynthesis and phytoplankton were not significantly affected by permethrin, except for Ceratium hirundinella. The dominance of Dinobryon divergens continued in the treated enclosures, whereas other flagellate species, Scenedesmus and Nitzschia occurred during the second half of the experiments in the control enclosure and pond.     

Arctodiaptomus (Rhabdodiaptomus) michaeli n.sp. (Copepoda,Calanoida) from Kashmir,India

Arctodiaptomus (Rhabdodiaptomus) michaeli n.sp. is described from the material collected in Alapathar Lake and Marsar Lake of Kashmir, India.     

Ecology of the zooplankton of a meromictic antarctic lagoon with special reference to Drepanopus bispinosus (Copepoda: Calanoida)

The zooplankton of Burton Lake, a meromictic lagoon with a tenuous connection to Crooked Fjord near Davis, Antarctica, was studied during the summer of 1981, when the lake was still ice-covered. Sampling occurred through a 10 cm diameter ice-hole. A plankton pump was used to investigate vertical changes in population density. A newly designed collapsible net was hauled vertically through the entire oxylimnion (6.5 m thick) to examine temporal changes in population structure and in the species composition of the zooplanktonic community. Four metazoan species occurred in the zooplankton: Drepanopus bispinosus and Paralabidocera antarctica (Copepoda), Rathkea lizzioides (Anthomedusae) and a cydippid ctenophore. Except for R. lizzioides, the lower limit of the vertical distributions occurred precisely at the oxycline at a depth of 8.15 m. The densities of both R. lizzioides and the ctenophore were low throughout the depth range 5.0–7.25 m and considerably higher above and below this stratum. The density of R. lizzioides increased greatly in a downward direction starting about 35 cm above the oxycline, and many individuals were capable of making excursions of about 10 cm downward past the chemocline into anoxic water. D. bispinosus had a more even vertical distribution than the medusa and ctenophore, but densities were higher in that portion of the oxylimnion lying below 6.0 m than above. The vertical distributions of R. lizzioides and D. bispinosus were stable over 24 h, but vertical migration occurred in that portion of the ctenophore population located above the low-density stratum. P. antarctica occurred in very small numbers. The ctenophore was uniformly distributed horizontally, but significant horizontal differences (among four stations) in mean vertical density occurred in adult D. bispinosus and R. lizzioides. The lowest density of D. bispinosus occurred at the station with the highest density of R. lizzioides. In early summer (11 December 1981), the mean densities of zooplankters within that portion of the oxylimnion overlying the anoxylimnion were D. bispinosus 550 m⁻³, ctenophore 410 m⁻³ and R. lizzioides 230 m⁻³. Throughout summer the absolute density and relative community proportion of R. lizzioides fell continuously, and these measures showed a comparable decline for adult D. bispinosus (almost entirely females). At the same time there was a consistent increase in the numbers of immature D. bispinosus. The density and community percentage of the ctenophore remained high (c. 480 m⁻³ and 44%, respectively) throughout December and early January, but declined thereafter. D. bispinosus is univoltine. Mature males appear in late autumn and mating occurs mainly in early winter, when significant numbers of mature females first appear. The species overwinters as adults, and ovigerous females first appear in midwinter. Males are short-lived and are already rare by the end of winter. Stage I nauplii are present in early spring, and naupliar development continues throughout spring and into early summer in company with an almost entirely female adult population. Stage I copepodites first appear in December and reach peak numbers in January. The last of the adult females from the previous winter disappear by late summer, but development of the immature copepodites continues into autumn. Females may store sperm for up to six months. Highly significant dry weight-length regressions were obtained for D. bispinosus. Mean clutch size for this species remained constant at about 24–25 eggs. The mean summer standing crop of total zooplankton was almost 80 mg (dry weight) m⁻³. This value is high compared with those of most other marine waters. The structure and composition of the zooplanktonic community of the lagoon were quite distinct from those of the fjord with which water was exchanged during January and February. The summer standing crop of the lagoon was substantially greater than that of the fjord in terms of both unit surface area and unit volume of water. A tentative food web for the lagoon is presented.     

Distribution and Seasonal Dynamics of the Abundance of Centropages abdominalis Sato and C. tenuiremis Thompson et Scott (Copepoda) in Amursky Bay, Sea of Japan

The distribution and seasonal dynamics of Centropages abdominalis and C. tenuiremis (Copepoda) in Amursky Bay (Sea of Japan) were studied from May through November 1991. C. abdominalis occurred in plankton from May through August and in November, with a peak density of more than 40000 specimens/m³ in June, at a temperature of 15–18°C. C. tenuiremis occurred from late June through November, with a maximum total density of 6900 specimens/m³ in August, at 23°C. During the observation period, the distribution of species in the bay was irregular due to the hydrological regime and sanitary conditions of water.     

A new species of Peltidium Philippi, 1839 (Crustacea,Copepoda, Harpacticoida) from the Pacific coast of Mexico

During the analysis of phytal meiobenthic samples collected from a rocky-sandy beach in the state of Nayarit, in the Mexican Pacific, several specimens of harpacticoid copepods were obtained and taxonomically examined. These specimens were found to represent an undescribed species of the peltidiid genus Peltidium Philippi, 1839. The new species, Peltidium nayarit sp. n. is described herein. It resembles Peltidium nichollsi Geddes and Peltidium lerneri Geddes from Bahamas but also the widespread Peltidium speciosum Thompson & Scott and Peltidium purpureum Philippi. The new species from the Mexican Pacific differs from its known congeners by its possession of a unique combination of characters, including a modified pectinate seta on the antennary exopod, three terminal setae on the second endopodal segment of leg 1, third exopodal segment of leg 1 with three elements, inner terminal claw twice as long as outer claw, female fifth leg with 5 exopodal setae, exopodal setae I-III stout, spinulose and seta IV being as long as seta V. This is the second species of the family known to be distributed in the Eastern Tropical Pacific and in Mexico. Pending additional data, the distribution of this species appears to be restricted to this area of the Mexican Pacific.     

Bottom Communities of Semyachik Lagoon (Kronotskii Biosphere Reserve, Eastern Kamchatka)

Bottom communities of Potamogeton filiformis,Zostera marina+ Z. japonica+ Macoma balthica, Enteromorpha prolifera, and a stony block–boulder intertidal community were distinguished in Semyachik Lagoon. The macrobenthos associated with these communities is described. Generally, the biomass and occurrence frequency indices of the macrozoobenthic communities of the lagoon are an order of magnitude lower than those of macrophytobenthic communities (Kafanov, Plekhov, 1998); therefore, they do not play a significant role in bottom community structure. With the exception of the stony block–boulder intertidal community, their spatial distribution is entirely determined by the distribution of underwater vegetation, which is completely controlled by the geomorphological and hydrological features of the lagoon.