Review of taxonomic studies on freshwater Cladocera from India with remarks on biogeography

Ninety three species (97 taxa) of freshwater Cladocera are reported from India. Remarks are made on the nature and composition of the Indian cladoceran fauna and as well on the biogeography of various taxa.     

Ecological studies of Cladocera in the ricefields of Tanjung Karang,Malaysia, subjected to pesticide treatment

Temporal changes in the population densities of four dominant Cladocera (Moina micrura, Diaphanosoma excisum, Alona guttata and Macrothrix spinosa) were studied in untreated and pesticide treated rice plots over a growing season. M. micrura was the first dominant species to occur in all the plots which were initially devoid of vegetation except for the newly transplanted rice seedlings. With the growth of the rice seedlings and the appearance of aquatic macrophytes, open water ricefields were transformed into vegetated littoral conditions precipitating the disappearance of M. micrura and the appearance of the littoral A. guttata and M. spinosa, and the eurytopic D. excisum. The cladoceran community was affected by spraying of the pesticide FMC35001, an analogue of Furadan®. The response of the four dominant species to the pesticide treatment is discussed.     

Annotated checklist of Senegalia and Vachellia (Fabaceae: Mimosoideae) for the Indian subcontinent

An annotated checklist of Senegalia Raf. and Vachellia Wight & Arn. taxa for the Indian subcontinent is presented, following the fragmentation and retypification of the former broadly defined genus Acacia Mill. The countries encompassed by this study include Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan and Sri Lanka. All indigenous species (and a few introductions) in this region previously referred to Acacia belong to Senegalia and Vachellia. All Acacia s.s. taxa are introduced (principally from Australia) and are not included in the study. There are 22 species of Senegalia (21 indigenous, 1 introduced; representing 23 taxa) and 21 species of Vachellia (12 indigenous, 9 introduced; representing 27 taxa) currently recognized for the subcontinent. The largest country, India, has most species. This checklist complements that which was recently provided for these genera in southeast Asia and China. Two names formerly recorded for the Indian subcontinent are excluded, namely, Senegalia intsia (L.) Maslin is a nomen confusum and Acacia pennata subsp. hainanensis (Hayata) I. C. Nielsen is now known to be restricted to southern China and Vietnam. Acacia eriantha Desv. is an unresolved name. The following new combinations are made herein: Senegalia tanjorensis (Ragup., Thoth. & A.Mahad.) A.S.Deshpande & Maslin, Vachellia campbellii (Arn.) A.S.Deshp., & Maslin and V. pseudowightii (Thoth.) A.S.Deshpande & Maslin. A lectotype has been selected for Acacia pennata var. canescens Graham ex Kurz (= Senegalia pennata (L.) Maslin).     

Mountain-associated clade endemism in an ancient frog family (Nyctibatrachidae) on the Indian subcontinent

Night frogs (Nyctibatrachidae) form a family endemic to the Western Ghats, a hill chain along the west coast of southern India. Extant members of this family are descendants of a lineage that originated on the subcontinent during its longtime isolation in the Late Cretaceous. Because the evolutionary history of Nyctibatrachidae has always been tightly connected to the subcontinent, these tropically-adapted frogs are an ideal group for studying how patterns of endemism originated and evolved during the Cenozoic in the Western Ghats. We used a combined set of mitochondrial and nuclear DNA fragments to investigate the phylogenetic relationships of 120 ingroup specimens of all known species of Nyctibatrachidae. Our analyses indicate that, although this family had an early origin on the Indian subcontinent, the early diversification of extant nyctibatrachids happened only in the Eocene. Biogeographic analyses show that dispersal across the Palghat gap and Shencottah gap was limited, which led to clade endemism within mountain ranges of the Western Ghats. It is likely that multiple biota have been affected simultaneously by these prominent geographical barriers. Our study therefore further highlights the importance of considering the Western Ghats-Sri Lanka biodiversity hotspot as an assemblage of distinct mountain regions, each containing endemism and deserving attention in future conservation planning.     

Predicting potential distribution of poorly known species with small database: the case of four‐horned antelope Tetracerus quadricornis on the Indian subcontinent

Information gaps on the distribution of data deficient and rare species such as four‐horned antelope (FHA) in Nepal may impair their conservation. We aimed to empirically predict the distribution of FHA in Nepal with the help of data from the Indian subcontinent. Additionally, we wanted to identify core areas and gaps within the reported range limits and to assess the degree of isolation of known Nepalese populations from the main distribution areas in India. The tropical part of the Indian subcontinent (65°–90° eastern longitude, 5°–30° northern latitude), that is, the areas south of the Himalayan Mountains. Using MaxEnt and accounting for sampling bias, we developed predictive distribution models from environmental and topographical variables, and known presence locations of the study species in India and Nepal. We address and discuss the use of target group vs. random background. The prediction map reveals a disjunct distribution of FHA with core areas in the tropical parts of central to southern–western India. At the scale of the Indian subcontinent, suitable FHA habitat area in Nepal was small. The Indo‐Gangetic Plain isolates Nepalese from the Indian FHA populations, but the distribution area extends further south than proposed by the current IUCN map. A low to intermediate temperature seasonality as well as low precipitation during the dry and warm season contributed most to the prediction of FHA distribution. The predicted distribution maps confirm other FHA range maps but also indicate that suitable areas exist south of the known range. Results further highlight that small populations in the Nepalese Terai Arc are isolated from the Indian core distribution and therefore might be under high extinction risk.     

Phenotypic variability of quantitative traits in Indian populations of Drosophila kikkawai

Drosophila kikkawai, which has colonized the Indian subcontinent in the recent past, exhibits geographical variations for five quantitative traits among eight Indian populations (8.29–32.7°N). Body weight, wing length, thorax length, abdominal bristles and ovariole number exhibit significant clinal variation with increase in latitude, while sternopleural bristles do not demonstrate such a trend. For the female sex, the slope values for body weight (2.25) and wing length (2.40) are higher but they are lower for thorax length (0.64) and ovariole number (0.51 per degree latitude). There is significant sexual dimorphism for the slope values only for body weight and thorax length suggesting simultaneous action of latitudinal selection pressure on these traits. However, the two sexes do not differ statistically in the latitudinal slope values for the wing length. A regression analysis of different traits on body weight implies correlated selection response on wing length and wing/thorax ratio while thorax length corresponds to changes in body size and does not differ in the two sexes. Regression analysis, on the basis of temperature-related climatic variables, evidence significantly higher association between all the five size-related traits and coefficient of variation of mean annual temperature (seasonal thermal amplitude; T _cv), T _min and relative humidity. Thus, genetic differentiation for quantitative traits in D. kikkawai are due to selective pressure from variable climatic conditions occurring on the Indian subcontinent.     

Review of Iberian Cladocera with remarks on ecology and biogeography

A checklist of 88 freshwater Cladocera from the Iberian Peninsula is given, based on the examination of approximately 1500 samples collected from all parts of the peninsula from 1976 to 1989. Ecology and species assemblages are considered. Distribution of the species versus regional limnology of the Iberian Peninsula is discussed.     

The Cladocera of Sri Lanka (Ceylon), with remarks on some species

The freshwater Cladocera of Sri Lanka has been revised based on the study of over 700 zooplankton samples collected from all habitat types during 1965–1980. The cladoceran fauna is represented by six families; members of the families Polyphemidae, Leptodoridae and Holopedidae are absent. The common temperate genus Daphnia is rare.Sixty-two species have been recorded from Sri Lanka. Of these, five are new records. Remarks on a few species are given with illustrations. The distribution of Cladocera in different types of habitats is discussed. The greatest species diversity was found in ponds. The Sri Lankan fauna is numerically and in species diversity typical of tropical cladoceran fauna. It resembles the southern Indian fauna very closely except for the absence in Sri Lanka of the genera Acroperus and Camptocercus.     

Desiccation tolerance and starvation resistance exhibit opposite latitudinal clines in Indian geographical populations of Drosophila kikkawai

Abstract. 1. Desiccation tolerance and starvation resistance demonstrated significant differentiation among seven Indian geographical populations of Drosophila kikkawai, collected along a latitudinal range of 12.6–32.7 °N. Lack of significant differences in two successive generations suggested that these physiological traits were genetically controlled. 2. North Indian populations of D. kikkawai displayed significantly higher desiccation tolerance than southern populations, whereas there was a reverse trend for starvation tolerance (r > 0.90). Regression slope values indicated an increase of 0.61 h for desiccation and a decrease of 1.71 h per degree latitude for starvation tolerance at 17 °C. The traits evidenced opposite latitudinal clines, and such data also matched thermal climatic conditions on the Indian subcontinent. The survival duration for such traits was significantly higher at 17 than at 25 °C. 3. Significantly higher starvation tolerance in south Indian populations might be due to large population size, species interactions, and higher metabolic rates in the humid tropical environments. In contrast, prolonged unfavourable colder climatic conditions are known to favour starvation tolerance in temperate regions. Thus, the causes of desiccation and starvation tolerance seem quite different under tropical and temperate conditions. 4. Starvation tolerance was correlated negatively with body weight and ovariole number, which might be due to a trade-off in favour of greater allocation to non-lipidic reserves for sustaining starvation tolerance in the tropics. Reduction in metabolic rate may not be applicable for observed higher starvation tolerance in the tropical populations. 5. Multiple regression analysis demonstrated a major effect of coefficient of variation of mean monthly temperature for both the traits of ecological significance. Thus, Indian geographical populations of D. kikkawai provided evidence of independent genetic divergence for starvation and desiccation tolerance under natural conditions.     

The distribution of chydorid Cladocera in Canada

The distribution of chydorid Cladocera in Canada is given based on the examination of 584 samples collected from all the provinces and territories from 1978 through to 1984. Some species show regional distributions, while others are widely distributed. The preferences shown by some species to particular substrates are discussed. Further evidence is presented to show that some taxa previously claimed to be conspecific in Europe and North America may be different. In some instances the adult males tend to be more highly differentiated than the females, particularly in the structure of the postabdomen. The importance of taxonomic and distributional studies in understanding the biogeography of North American chydorids is discussed.     

Salinity and the distribution of Cladocera in Warri River,Nigeria

Hydrobiological investigations of the water quality and plankton of Warri River started in 1981, shortly before the commissioning of the Delta Steel Plant on the banks of the river at Aladja. The 150 km of river gradates from pure freshwater through brackish to marine and so provides a suitable habitat for a study of the limits of migration of any group of zooplankton. The Cladocera of Warri River consists of two bosminids, thirteen chydorids, three daphniids, three macrothricids, one moinid, and two sidids. All except the sididPenilia sp. are well known freshwater forms, which are limited in longitudinal distribution to areas with salinity below 2.5‰. Penilia sp. found in Warri River were restricted to the truely brackish-water areas with salinity values of 7‰ −8‰. In this respect they represent the first reported brackish water Cladocera in Africa. They also differ fromPenilia avirostris Dana found in marine habitats in certain morphological details, and so the Warri RiverPenilia may be a new taxon.     

Introgression as a Factor in the Evolution of Polytypical Plankton Cladocera

The genera Bosmina and Daphnia offer considerable taxonomical difficulties due to the existence of a very great number of different races. An attempt has been made to understand this phenomenon mainly as the result of introgressive processes.     

Diel migration and vertical distribution of Cladocera in Lake D. Helvecio (Minas Gerais,Brazil)

Six genera of Clad ocera (Diaphanosoma, Daphnia, Ceriodaphnia, Moina, Bosmina, Bosminopsis), each of them usually with only one species were found in Lake D. Helvecio, a natural valley lake located in the eastern part of Brazil. Diurnal migratory movements of the organisms observed in this lake showed a different pattern in different species. Closely related species, which explore the same food source, live in different layers, thus avoiding interspecific competition. The migratory behaviour of the species was studied mainly in relation to temperature and oxygen distribution in the lake. Thus, analyses were made in the summer (January, 1978) when a strong stratification occurs with the establishment of a thermocline and an oxycline. Comparisons were made also with the data obtained in winter (July, 1978), when a complete mixing of water occurs.     

Cladocera from pokhara valley,nepal with notes on distribution

A study made on collections of zooplankton from lakes and ponds in Pokhara Valley, Nepal yielded 23 species of Cladocera of which 1 i species are recorded for the first time in Nepal. This brings the recorded Nepalese Cladocera to 39 species. All the species recorded in the present study are illustrated and described briefly. A compilation of previous and present records is given with a short discussion of the species composition.     

Altitudinal distribution of tropical planktonic Cladocera

The altitudinal distributions of planktonic Cladocera in Africa in three latitudinal bands: 0–10 °, 10–20 ° and 28–31 ° are described. Some species have altitudinal ranges of 2000 m within a latitudinal band of 10 °. It is possible to distinguish tropical species which do not extend up to high altitudes, particularly at higher latitudes. At the lowest latitudes, some species are found only at high altitudes, but occur at progressively lower altitudes with increasing latitude: Daphnia pulex and D. obtusa are good examples. A study in South America, with a smaller database, gives similar results.     

Contributions to the knowledge of the Cladocera of north-east Thailand

Examination of 200 samples from 93 freshwater habitats in north-eastThailand revealed 60 taxa of Cladocera, of which 31 are new to the Thaifauna. Six species (Disparalona caudata Smirnov; Leydigialaevis Gurney; Leydigiopsis sp.; Macrothrix flabelligeraSmirnov; Macrothrix cf. paulensis Sars; and Pseudosidaramosa Daday) are new to Asia. The majority of the Cladocera recorded arecircumtropical species. Comments and figures are presented on several ofthe new records for Asia and Thailand. This revised version was published online in July 2006 with corrections to the Cover Date.     

东海浮游枝角类生态学研究

根据1997~2000年在东海23°30′~33°00′N、118°30′~128°00′E海域4个季节的海洋调查资料,探讨了东海浮游枝角类生态特征、数量变化和相应的动力学。结果表明,枝角类丰度夏季最高(17.16 ind.(100 m3)-1),秋季(14.68 ind.(100 m3)-1)次之,春季(0.63 ind.(100 m3)-1)较低,冬季该类未出现。春、夏、秋季的肥胖三角氵蚤(Evadne tergestina)和夏季的鸟喙尖头氵蚤(Penilia avirostris)是影响枝角类数量分布的主要种;春、夏、秋季枝角类总丰度与盐度呈负线性相关关系,与水温相关关系不显著。枝角类较高丰度区常位于沿岸淡水水团与其他水团交汇处偏沿岸水一侧。其数量变化动力主要来自沿岸冲淡水势力,特别是长江冲淡水势力的消长。枝角类在东海出现率较低,有一定的集群性,较高丰度的分布基本上局限在冲淡水势力影响范围内,其高丰度的水域是沿岸水团的一个重要标志。     

Structure and dynamics of zooplankton communities,Alligator Rivers Region,N.T., Australia

Biological monitoring in the Alligator Rivers region, northern Australia, provides baseline ecological information to assess the impact of uranium mining and milling and settlement in the area. Spatial and temporal variations 1978–1980 in zooplankton communities of the Magela Creek, a tributary of the East Alligator River, are described. Extremely diverse plankton assemblages occur late in the wet season (Dec.–May), with up to 80 taxa of rotifers and microcrustacea in some billabongs (= ox-bows), while there is a decrease in diversity but increase in population density as the dry season progresses. Natural fluctuations in water quality may be extreme, and limiting to plankters common elsewhere in the tropics. The plankton is composed largely of littoral or epiphytic taxa, with endemic species in all groups.