The Cladocera and Copepoda of the Alta water-course, Northern Norway

Cladocera and Copepoda fauna, from ten lakes in the Alta water-course,northern Norway, have been collected and investigated. A totalof 42 species (34 Cladocera and 8 Copepoda) were recorded. Thenumber of Cladoceran species is high when compared with thatregistered for other areas of similar latitude, and Cladoceranspecies abundance is also greater than that reported for otherregions of northern and central Scandinavia. In addition, themean number of planktonic species present at any given timein the lakes (4.9 Cladocera and 3.4 Copepoda) was comparativelyhigh. Eight species have never been recorded as existing farthernorth than the Alta water-course, Three other species have beenrecorded at higher latitudes in North America, but not in Eurasia.Several species, of which there are only a few published records,arc rare in northern Scandinavia, and nine species were notconsidered by Illies (1978), as existing in the region of thepresent study.     

Review of the fauna of Rotatoria,Cladocera, and Copepoda of the basin of the Anadyr’ River

The zooplankton composition is studied in the thermokarst, glacial and meteorite lakes, channels, former riverbeds, and hollows in the basin of Anadyr’. We found 174 taxa: 78, Rotatoria, 55, Cladocera, and 41, Copepoda. The most diverse is the lake fauna: 51 taxa of Rotatoria, 48, Cladocera, and 37, Copepoda. The thermokarst Lake Maiorskoe hosts 68 taxa: 31, Rotatoria, 14, Cladocera, and 23, Copepoda, wheras the cold ultraoligotrophic Lake El’gygytgyn features only one species of Cyclop of the group scutifer Cyclops neymanae Strel., and Rotatoria and Cladocera are present as allochtonous forms. The Copepoda illustrate the relations of the Anadyr’ fauna with those of Europe, North America, and Japan.     

Report on a collection of cladocera and copepoda from Nepal

22 species of Cladocera and 14 species of Copepoda are reported, mainly from Kathmandu valley, Central Nepal and some from high-altitude lakes in the Khumbu area, East Nepal. Two species are new to science; neither can, however, be named due to inadequate material. The relation between Macrothrix laticornis (Jurine, 1820), M. spinosa King, 1853 and M. goeldii Richard, 1897 is discussed; M. goeldii is set as synonym to M. spinosa; new morphological criteria, permetting a separation to M. laticornis and M. spinosa, are given. Some biogeographical aspects of the fauna encountered are: 1) among Copepoda two calanoïds of oriental origin and one of supposed palaearctic origin reach Kathmandu valley; all other Copepoda are circumtropical or cosmopolite species; no oriental Cyclopoïda were found; 2) at higher altitudes, no Cyclopoïda were found, and the Calanoïda were endemic species of the palaearctic genus Arctodiaptomus; 3) no oriental Cladocera were found in Kathmandu valley; the majority of species were cosmopolitan, the remainder circumtropical; 4) at high altitudes, endemic species of palaearctic genera exist next to a set of cosmopolitans.Contribution no 21 from the Netherlands Centre for Alpine Biological Research     

Fatty acid composition of Cladocera and Copepoda from lakes of contrasting temperature

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The Freshwater Zooplankton of Sri Lanka,with a Discussion of Tropical Freshwater Zooplankton Composition

Based on the study of over 500 zooplankton samples collected in Sri Lanka (Ceylon) during 1965–1974, the species composition from different habitats is analysed. The zooplankton assemblage is typically tropical with relatively few species of Cladocera and Copepoda. The Rotifera include a large number of species of the genus Brachionus. The limnetic zooplankton resembles the pond zooplankton closely in that all the eurytopic species found in the different types of habitats, including ponds, also occur in the limnetic zooplankton. The large Cladocera belonging to the genus Daphnia are very rare. In general, large zooplankters are absent. The size composition of the zooplankton has a smaller range than in temperate regions. This is due to the absence of large-sized zooplankton species. The reasons for the differences in species variety and size composition between zooplankton of temperate and tropical regions is perhaps due to a number of factors. These include the effects of high and uniform temperatures, food availability and predation by fish and invertebrates.     

Zooplankton Associations in the Middle Niger-Sokoto Basin (Nigeria: West Africa)

The species richness of the crustacean zooplankton (Cladocera and Copepoda) and Rotifera in the Middle Niger-Sokoto Basin is characterised from 351 samples collected from 109 localities. 26(4) Cladocera, 18(8) Copepoda and 38(8) Rotifera are recorded. Figures in brackets indicate first records of species for Nigeria. Zooplancton associations of the Middle Niger are compared with one of its major tributaries, River Sokoto, and seven of its minor tributaries using similarity indices of Sørensen and Pearsons Product Moment Cluster Coefficients. The Rivers Sokoto and Shagari consistently had the highest similarity of zooplankton associations, for all combinations of rivers studied with r = 0.54 (Cladocera), r = 0.91 (Copepoda) and r = 0.54 (Rotifera). Zooplankton associations of the Middle Niger are weakly correlated with all tributaries studied (r < 0.1). Species composition and hydrology of the River Sokoto Basin are also compared with previous studies in Nigeria. A Principal Component Analysis of species abundance accounted for 54 % of the total variance. It again confirmed the similarity of the branches Sokoto and Shagari. Two groups of species assemblages were identified. The occurrence of Asplanchna sp., Testudinella patina and Microcyclops varicans in one group appears related to microhabitat selection. The other group made up of Brachionus calyciflorus calyciflorus, Macrothrix spinosa, Lecane luna, Thermocyclops decipiens and Metacyclops minutus is suspected to be linked to physico-chemistry. Further studies on the hydrology and physico-chemistry are required for definitive identification of both factors.     

Zooplankton dynamic of Lake Prespa (Macedonia)

The composition and temporal abundance patterns of zooplankton community in Lake Prespa pelagic zone were studied throughout an annual cycle (October 2008–September 2009). Eighteen species (10 Rotifera, 5 Cladocera, 2 Copepoda, 1 Mollusca) were evidenced. It includes Arctodiaptomus steindachneri, an endemic calanoid of the Western Balkans. The zooplankton density varied during the investigated period and certain seasonal successions in temporal transpositions of their maximal development were noticed. The total zooplankton density was much higher in spring and summer period. The representatives of subclass Copepoda were dominant during the whole year. The dominant species was A. steindachneri. At the second place (with exception of the winter period) were the Cladocera representatives. The dominant species was Daphnia cucullata. At the third and fourth place were rotifers and larval form of Dreissena polymorpha, respectively. The quantitative presence of the Copepoda representatives was significantly lower in terms of the previous investigations. The Cladocera quantity reached high values during this period, particularly in summer. Such altering in the quantitative ratio between Copepoda and Cladocera in favor of the Cladocera, especially high quantitative presence of D. cucullata, typical for eutrophic lakes, imply of significant changes in zooplankton community and changes of the water quality in Lake Prespa pelagial.     

Phylogeography of West Indies Coral snakes (Micrurus): Island colonisation and banding patterns

In this study, we analyse New World coral snakes in a phylogenetic framework based upon an increased molecular data set, including novel sequences for the only two sympatric species known from an island (Trinidad, West Indies). Their presence in Trinidad and absence in Tobago offers a unique system to study the phylogeography of the region. We assess the tempo and mode of colonisation of Micrurus on the island, in addition to discussing the phylogenetic relationships for the genus Micrurus concerning two phenotypic traits, body and tail banding patterns. These relationships are analysed for the first time on statistical coalescent phylogeographic discrete ancestral reconstruction. We find a robust phylogenetic component in these characteristics, where strongly supported clades are recovered: prior to the onset of the Early Miocene, a triadal and tricolour tail clade composed of species from South America, and a second clade dating to the Middle‐Late‐ Miocene with monadal and bicolour tails widely distributed from North to South America. The divergence between clades dates to the Oligocene and suggests an ancient pre‐isthmus divergence supporting the arrival of the triadal clade into South America, before the connection between Central and South America was established. We find the two coral snakes present in the West Indies, M. diutius and M. circinalis, belong to the triadal and monadal clades, respectively. Guyana and Trinidad Micrurus diutius share the same haplotypes suggesting a Late Pleistocene–Holocene vicariance when sea level rises separated Trinidad from the mainland. A second lineage of diutius‐like snakes is present in Guyana and is confirmed as M. lemniscatus which is assigned as a voucher and restricts the type locality for M. lemniscatus.     

Zooplankton associations in East African lakes spanning a wide salinity range

Abstract The zooplankton of 38 East African lakes has been analysed in terms of species richness and dominance. The conductivities of the lakes range from 48 to 72 500 µS cm^–1 20 °C. The lakes generally contain more species of rotifers than either Copepoda or Cladocera. The number of species of rotifers begins to decline at a conductivity below 1000 µS cm^–1, and falls to 2 or 3 species above 3000 µS cm^–1. Similar reductions occur in the Copepoda and Cladocera.Many species can be dominant at conductivities below 1000 µS cm^–1, but the range is restricted progressively with increasing salinity. The dominant species of Rotifera, Copepoda and Cladocera change independently along the salinity gradient, but there are indications of interactions and modifications of community structure by predation and competition.     

A Seasonal Quantitative Study of the Littoral Cladocera and Copepoda in a Bog Pond and an Acid Marsh in Newfoundland

A quantitative study was made of the littoral microcrustaceans in a bog pond and an acid marsh located on the Avalon Peninsula, Newfoundland, from May, 1972 to May, 1973. A total of 17 species of Cladocera and 7 species of Copepoda were found in La Manche Marsh, while 21 species of Cladocera and 5 species of Copepoda were collected in Round Pond. The maximum standing stocks were similar in the two localities. The dominant forms in the summer and fall in La Manche Marsh were Cladocera: Acantholeberis curvirostris, Biapertura intermedia, Chydorus sphaericus, and Ilyocryptus spinifer. In the winter the copepod, Macrocyclops albidus, was dominant, while Cyclops varicans rubellus was the most abundant species in the spring. Round Pond also was dominated by Cladocera in the summer and fall; namely, Acroperus alonoides, Alona rustica, Alonella excisa, Chydorus sphaericus, and Sida crystallina. The copepods, Eucyclops agilis and Macrocyclops albidus, were dominant in the winter and early spring.     

The dry weight estimate of biomass in a selection of Cladocera,Copepoda and Rotifera from the plankton,periphyton and benthos of continental waters

Summary A procedure for determining dry weights has been standardized and applied to a number of Cladocera, Copepoda and Rotatoria. In most of the Cladocera, regression equations of the exponential type, relating dry weight to body length, were computed. In the Copepoda, one equation per suborder was computed, and suggestions for future refinements are made. In both groups, a fairly satisfactory agreement was found with literature data where these exist. In both groups, the egg and embryo weight proved to be considerable, relative to the weight of the adult female. In Rotatoria, 4 species could be dealt with in size-classes, and their weight increment per unit length was found to be lower than in the Cladocera and Copepoda. A large number of species were weighed as adults only. A conclusion applicable to the 3 groups is that, as a rule, limnetic species weigh relatively less than littoral, periphytic or benthic species. Even within a species, populations with a more pronounced limnetic way of life weigh less than populations of littoral nature.     

Allozyme evidence for the origin and diversification of Gossypium barbadense L.

Summary Gossypium barbadense L. is a commercially important cotton species of tropical South American origin presently grownin many regions of the world. The species is morphologically diverse, consisting of a wide range of wild (or feral), commensal, landrace, and highly improvedcommercial forms. We performed allozyme analysis on 153 accessions representing the spectrum of G. barbadense diversityto ascertain the geographic origin of the species, its patterns of diffusion subsequent to domestication, and to reveal infraspecific relationships. Levels ofgenetic variation in G. barbadense are moderate. Of 59 loci scored, 24 were polymorphic, with a mean number of alleles perlocus of 1.69 and an average panmictic heterozygosity of 0.062. Principal component analysis revealed geographic clustering of accessions into six relativelydiscrete regions. Gene frequencies at many loci are significantly heterogeneous among these regions, with an average G _STof 0.272. Northwestern South America contains the greatest genetic variability; we suggest that this region is the ancestral home of the species. The data indicate separate diffusion pathways from this region into Argentina-Paraguay and into eastern and northern South America east of the Andes. Caribbean Island and Central American forms appear to be derived from the latter. These diffusion pathways are in accordance with morphological evidence and historical record. In contrast to expectations based on geographic proximity, Pacific Island forms have their closest affinity to accessions from eastern South America. Advanced cultivated stocks seem largely derived from western Andean material, but also contain introgressed G. hirsutum germ plasm. Introgression was relatively high (22%–50% of accessions) in commercial stocks and in forms from Argentina-Paraguay and various Pacific Islands, but was conspicuously low or absent in material from Central America and the Caribbean, where commensal and commercial forms of both species are sympatric.     

The Species and Size Composition of Tropical Freshwater Zooplankton with Special Reference to the Oriental Region (South East Asia)

A contrast between temperate and tropical Cladocera, Copepoda and Rotifera zooplankton fauna shows a markedly different size composition and species diversity. There are fewer species, and these are generally smaller in the tropics than in either the North or South Temperate Zones. Larger species of the genera Daphnia and Simocephalus are relatively rare in the tropics, while members of Eurycerus and Saycia are absent. Members of the families Holopedidae, Leptodoridae and Polyphemidae increase in abundance toward the temperate regions. Two small cyclopoid copepods are common in tropical zooplankton, while many of the common larger species of other regions are absent or very rare. The chief rotifer components are Keratella tropica and species of Brachionus.     

Shifts in zooplankton communities in high-mountain lakes induced by singular events (fish stocking,earthquakes): evidence from a 20-year survey in Slovenia (Central Europe)

Thirteen mountain lakes, originally fishless, at 1325 and 2150 m a.s.l., with the maximum depths ranging from two to 15 m, and areas of 0.3 to 4.5 ha, were monitored between 1991 and 2012 in the Triglav National Park (Slovenia, Central Europe). The lakes are located on limestone bedrock, with no surface inflow or outflow. They range from ultra-oligotrophic to hypertrophic. They were stocked with fish between late 1920s and 1996. The zooplankton samples were collected as composites from the bottom to the surface at the deepest point of the lake, for both qualitative and quantitative analyses. In situ physical parameters in the water column were measured, and the samples for chemical analyses were collected in parallel with the zooplankton sampling. Thirty-two species, including Copepoda, Cladocera, Rotifera and Ciliata, were recorded. They belonged to three ecological groups: (1) constitutive, (2) scout and (3) benthic species. In some of the lakes, the species composition remained stable over the study period, but in lakes stocked with fish, significant changes occurred, in both species composition and biomass. Large-bodied species of Copepoda and Cladocera were eliminated by fish allowing small-bodied planktonic species of Copepoda, Cladocera and Rotifera to dominate the community, along with benthic species, associated with algal mats. The lake, stocked with fish in the 1920s, was hit by two strong consecutive earthquakes, in 1998 and 2004, after which a significant change in species composition and biomass was recorded.

     

Influence of Chaoborus density on the effects of an insecticide on zooplankton communities in ponds

Zooplankton communities with a high or low density of Chaoborus larvae were established in outdoor concrete ponds, to which a carbamate insecticide, carbaryl, was applied at 0.1 or 0.5 mg l⁻¹. The lower concentration of the chemical was harmful only to Cladocera. The higher concentration damaged Chaoborus, Copepoda, and some rotifer species, as well as Cladocera. In the ponds with a low density of Chaoborus, chemical application altered the cladoceran community from dominance by Daphnia to that by Bosmina and Moina. In the ponds with a high density of Chaoborus, Chaoborus excluded cladocerans from the zooplankton community presumably by predation, and supported the dominance of rotifers. Cladocera did not recover after application of the chemical, even when Chaoborus was eliminated by the higher concentration of chemical. The relatively rapid recovery of Chaoborus seemed to interrupt the recovery of Cladocera.     

Presence of the Chytrid Fungus Batrachochytrium dendrobatidis in Populations of the Critically Endangered Frog Mannophryne olmonae in Tobago, West Indies

The emerging infectious disease chytridiomycosis is prevalent in Central and South America, and has caused catastrophic declines of amphibian populations in the Neotropics. The responsible organism, Batrachochytrium dendrobatidis, has been recorded on three West Indian islands, but the whole of the Caribbean region is predicted to offer a suitable environment for the disease. Monitoring the spread of chytridiomycosis is thus a priority in this region, which has exceptionally high levels of amphibian endemism. PCR analysis of 124 amphibian skin swabs in Tobago (Republic of Trinidad and Tobago) demonstrated the presence of B. dendrobatidis in three widely separated populations of the frog Mannophryne olmonae, which is listed as Critically Endangered on the basis of recent population declines. Chytridiomycosis is presently endemic in this species, with a prevalence of about 20% and no associated clinical disease. Increased susceptibility to chytridiomycosis from climate change is unlikely in amphibian populations in Tobago, as this island does not have high montane environments, but remains a possibility in the sister island of Trinidad. Preventing the spread of chytridiomycosis within and between these and other Caribbean islands should be a major goal of practical conservation measures for amphibians in the region.     

Micro-benthic crustacean communities in tundra lakes of North-East European Russia

We studied micro-benthic copepods and cladocerans in the bottom substrates of 12 lakes in the Bol’shezemel’skaya tundra in North-East European Russia during the summer. About 30 species of Cladocera and 28 species and subspecies of Copepoda were found. The majority of the micro-crustaceans are palaearctic or northern palaearctic. But the harpacticoid fauna of the western part of the studied region had specific European features, and three species of the harpacticoid fauna in the eastern part of the region were Siberian. It is therefore a boundary territory for two zoogeographical regions, the arctic and subarctic zones. Acidophilic (Arcticocamptus arcticus (Lilljeborg 1902)) and halophilic (Microsetella norvegica (Boeck 1864)) harpacticoid species were found in the lakes of the eastern part of Bol’shezemel’skaya tundra. On basis of their way of locomotion we distinguished five ecological groups and on basis of their feeding habits four ecological groups of micro-crustaceans. Groups with a similar way of locomotion were likely distributed over the studied water bodies. Habitat (inshore versus offshore), substrate particle size and substrate hardness were of paramount importance for the species distribution.     

Some Crustacea Copepoda from Venezuela

The study of 38 samples of aquatic fauna from Venezuela increased the number of known species here from 28 to 66. Fifteen new species for science are described. A list of Copepoda known from the other regions of South America is presented. From this list, it can be said that only 50% of the inland water Copepoda living actually in Venezuela are known.     

Cladocera and free-living Copepoda from the Fouta Djalon and adjacent mountain areas in West Africa

Thirty-two species of Cladocera and 27 species of free-living copepods were identified in a series of samples collected in 25 localities in and around the Fouta Djalon mountains, West Africa. Beside great richness in numbers of species, the nature of the fauna is noteworthy: at least 20% of the Cladocera and 50% of the copepods are endemic to West Africa. Possible palaeoclimatological reasons for this are discussed. The cladoceran genus Streblocerus is recorded from Africa for the first time. It is an element of northern origin in the fauna of West Africa. More examples of this kind are documented among the Copepoda Cyclopoida and Harpacticoida, but the bulk of the fauna is evidently of tropical origin. In particular, great adaptive radiation is occurring in the local representatives of the genus Tropocyclops. Three new species of Parastenocaris are described; they are the first representatives of this genus found in West Africa.     

Population structure and cryptic speciation in bonnethead sharks Sphyrna tiburo in the south‐eastern U.S.A. and Caribbean

Population structure and lineage diversification within a small, non‐dispersive hammerhead shark species, the bonnethead shark Sphyrna tiburo, was assessed. Sphyrna tiburo is currently described as one continuously distributed species along the Atlantic continental margins of North, Central and South America, but recent genetic analysis of an insular population (Trinidad) suggests the possibility of cryptic speciation. To address this issue S. tiburo were sampled at six sites along c. 6200 km of continuous, continental coastline and from one island location (Grand Bahama) across a discontinuity in their distribution (the Straits of Florida), in order to test if they constitute a single lineage over this distribution. A total of 1030 bp of the mitochondrial control region (CR) was obtained for 239 S. tiburo, revealing 73 distinct haplotypes, high nucleotide diversity (0·01089) and a pair of highly divergent lineages estimated to have separated 3·61–5·62 million years ago. Mitochondrial cytochrome oxidase I and nuclear internal transcribed spacer loci show the same pattern. Divergence is similar within S. tiburo to that observed between established elasmobranch sister species, providing further evidence of cryptic speciation. A global AMOVA based on CR confirms that genetic diversity is primarily partitioned among populations (Φ_ST = 0·828, P < 0·001) because the divergent lineages are almost perfectly segregated between Belize and North America–The Bahamas. An AMOVA consisting solely of the North American and Bahamian samples is also significantly different from zero (Φ_ST = 0·088, P < 0·001) and pairwise F_ST is significantly different between all sites. These findings suggest that S. tiburo comprises a species complex and supports previous research indicating fine population structure, which has implications for fisheries management and biodiversity conservation.