12 resultados para taxonomy of innovation

em Aquatic Commons


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Taxonomic descriptions, line drawings, and references are given for the 30 named and 5 unnamed species of North American fish Eimeriidae. In addition, a key was developed based on available morphologic data to distinguish between similar species. Taxa are divided into two genera: Eimeria (27 species) which are tetr&sporocystic with dizoic, nonbivalved sporocysts, and Goussia (3 species) which are tetrasporocystic with dizoic, bivalved sporocysts that lack Stleda bodies and have sporocyst walls composed of two longitudinal valves. (PDF file contains 24 pages.)

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This paper considers the taxonomy of most of the synodontis spp. present in the main drainage basins of West Africa. The first section consists of a key to the sixteen species known to occur in Lake Kainji. Nigeria. A second section considers species which are reputed to live in the area and therefore might occur in the lake. It is suggested that several of the latter group are synonymous with better known species.

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Ghost shrimp and mud shrimp in the decapod infraorder Thalassinidea are ecologically important members of many benthic intertidal and shallow subtidal infaunal communities, largely due to the sediment filtration and mixing that result from their burrowing and feeding behavior. These activities considerably modify their immediate environment and have made these cryptic animals extremely interesting to scientists in terms of their behavior, ecology, and classification. Over 20 years ago, seven species of thalassinideans were known from the South Atlantic Bight (Cape Hatteras, NC to Cape Canaveral, FL). During this study, the examination of extensive collections from the National Museum of Natural History (NMNH), the Southeastern Regional Taxonomic Center (SERTC), and regional institutions, resulted in the identification of 14 species of thalassinideans currently known to occur within this region. The family Axiidae is represented by three species: Axius armatus, Calaxius jenneri, and Paraxiopsis gracilimana; the Callianassidae by six: Biffarius biformis, B. cf. fragilis, Callichirus major, Cheramus marginatus, Gilvossius setimanus, and Necallianassa berylae; the Calocarididae by two: Calocaris templemani and Acanthaxius hirsutimanus; and the families Laomediidae, Thomassiniidae, and Upogebiidae are each represented by one: Naushonia crangonoides, Crosniera wennerae, and Upogebia affinis, respectively. An illustrated key is presented for species level identification and supplemental notes on the ecology, distribution, and taxonomy of the species are provided.(PDF file contains 38 pages.)

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The taxonomy of African Clarias was reviewed. It was emphasized that much confusion still exists in this taxonomy. The major sources of this confusion were outlined. There are now only about 33 valid species of the 122 original species so far described in Africa. The implications of the present state of African Clarias taxonomy for the field worker were highlighted. In particular the need for the field worker to be an informed amateur taxonomist in addition to the possession of a good knowledge of the biology of his fish was emphasized. The connection between this and a successful Clarias culture was pointed out

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This bibliography covers the literature up to the end of 1978. The criteria used in the selection of references were that they should aid identification of invertebrates directly; thus, works solely concerned with the taxonomy of a particular group are in general omitted unless they contain a key. Some check-lists are however included where they give current nomenclature. The references are arranged alphabetically within each group and deal mainly with macro-invertebrates but include available keys to some microscopic invertebrates. Internal parasites and hymenopterous parasitoids are omitted. For insects the life stages to which the key applies are given where this is not clear in the reference. A number of keys to non-aquatic stages have been included in the hope that they may prove useful in certain circumstances. In addition, under a general head, latest check-lists are referred to together with bibliographies of algal keys and a guide for the identification of British water plants.

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About 40 years have passed since the discovery of picophytoplankton; the present knowledge of the taxonomy, physiology and ecology of these tiny photoautotrophic cells offers new perspectives on the importance of the microbial contribution to global biogeochemical cycles and food webs. This review focuses on the relationships among the components of picophytoplankton (picocyanobacteria and the picoplanktic eukaryotes) and biotic and abiotic environmental factors. The dynamics of picophytoplankton in aquatic ecosystems are strictly dependent upon basin size and trophy, temperature, and nutrient and light limitation, but they are also regulated by grazing and viral-induced lysis. The review considers: the pros and cons of the molecular approach to the study of the taxonomy of freshwater Synechococcus spp.; the importance of ecological aspects in understanding the puzzle of picophytoplankton phylogeny (genotype vs ecotype); and the role of biotic vs abiotic interactions in controlling picophytoplankton dynamics. Biotic, top-down control mechanisms are reviewed as well as knowledge of other biological interactions.

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About 40 years have passed since the discovery of picophytoplankton; the present knowledge of the taxonomy, physiology and ecology of these tiny photoautotrophic cells offers new perspectives on the importance of the microbial contribution to global biogeochemical cycles and food webs. This review focuses on the relationships among the components of picophytoplankton (picocyanobacteria and the picoplanktic eukaryotes) and biotic and abiotic environmental factors. The dynamics of picophytoplankton in aquatic ecosystems are strictly dependent upon basin size and trophy, temperature, and nutrient and light limitation, but they are also regulated by grazing and viral-induced lysis. The review considers: the pros and cons of the molecular approach to the study of the taxonomy of freshwater Synechococcus spp.; the importance of ecological aspects in understanding the puzzle of picophytoplankton phylogeny (genotype vs ecotype); and the role of biotic vs abiotic interactions in controlling picophytoplankton dynamics. Biotic, top-down control mechanisms are reviewed as well as knowledge of other biological interactions.

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Most Copepoda pass through, first, a series of nauplius stages, and then through a series of copepodid stages (or cyclops stages), in which the general form of the adult is assumed. ... In the first place, the differentiation between the larvae of the various copepod species to be found in the plankton, both marine and fresh water, greatly augments the value and accuracy of quantitative and qualitative plankton analyses, because many species spend a large portion of their life span in an immature condition. In the second place, the taxonomy of the Copepoda is admittedly not completely satisfactory ...

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Morphology and taxonomy of four species of Ulva i.e. U. anandii Amjad et Shameel sp. nov., U. bifrons Ardre, U. saifullahii Amjad et Shameel sp. nov. and U. taeniata (Setchell) et Gardner were described for the first time from Pakistan. Their anatomy has been investigated in detail and compared with the allied species. A taxonomic comment has been written on U. grandis Saifullah et Nizamuddin.

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The collection of blue green algae kept at the herbarium of the Royal Botanical Gardens, Peradeniya, was collected by Ferguson more than 70 years ago. Since then many changes have taken place in the taxonomy of the blue green algae. West (1902), Lemmermann (1907), Wine (1915), Crow (1923), Bharadwaja (1934) and Holsinger (1935) had described some of the blue green algae of Ceylon. While examining the collections of blue green algae kept at the herbarium, the authors found that most of the identifications were incorrect and required revision. In the present paper 20 blue green algae are described. The classification and key to the species are based on the characters given by Desikachary (1959). Blue green algae are important to fisheries since Chanos larvae feed on them.

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The taxonomy of the mud crab, Scylla serrata has become a topic of interest. Alcock (1899) described this species from Indian waters. It was considered that under the genus Scylla, only one species, namely, Scylla serrata was valid. But Estampador (1949) revised the genus and reported the occurrence of four sorts, Scylla serrata, S. tranquebarica, S. oceanica and a variety S. serrata, var paramarnosain in Philippine waters. He established his claim based on the morphology such as colouration, relative length of chelae and also on the cytological events during gametogenesis. Serene (1952) pointed out that two distinct categories under this genus were demonstrable on the basis of colouration. But Stephenson & Campbell (1960) concluded them as only synonyms, but pointed out the need for further investigations.

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Sea cucumbers belong to phylum Echinodermata, order Holothuroidea are an abundant and diverse group of Invertebrates, with over 1400 species occuring from the intertidal to the deepest oceanic trenches. Sea cucumbers are important components of the food chain in temperate and coral reef ecosystems and they play an important role as deposite feeders and suspension feeders. Rapid decline in populations may have serious consequences for the survival of other species that are part of the same complex food web,as the eggs, larve and juveniles constitute an important food source for the other marine species including crustaceans, fish and mollusks. In addition sea cucumbers are often called the earthworms of the sea, because they are responsible for the extensive shifting and mixing of the substrate, and recycling of detrital matter. Sea cucumbers consume and grind sediment and organic material into finer particles , turning over the top layers of sediment in lagoons , reefs and other habitats and allowing the penetration of oxygen. While the taxonomy of the holothurian families is generally well known , the distinction of similar species is difficult. There are relatively few holothurian taxonomist.Most sea cucumber species can be identified by Holothurin taxonomists by using the calcareous skeletal ossicles found in the body wall. In this study , at first a sea cucumber from Kish island in Persian gulf has recognized. Individuals collected from west and east extend far away into north and south of coral reefs by diving. I have checked them morphologically and anatomically.Then with key to the orders of the Holothuroidea, They belong to the Aspidochirotida with key to the families of Aspidochirotida, they were in Stichopodidae families and with key to the genus of Stchopodidae, they were Stichopus. Then ossicles were extracted at National Museum of Natural History, by Dr David Pawson. The ossicles were measured on a transect across a slide prepared from the mid-dorsal region of each specimen.The one we have in the shallow waters of Kish island, is Stichopus hermanni, a massive holothurian, body broad, considerably flattened ventraly ,the dorsal side slightly arched and the lateral sides almost vertical; body wall fairy thick and soft ; mouth subterminal; anus central; tentacles usually 20 in number of length and leaf shaped. Numerous ossicles consisting of table with large discs having usually 7 to 15 peripheral holes, but often irregular or incomplete and spire of moderate height ending in a group of spinelets, rosettes of variable development, and c-shaped rods. Color (exept papillae)partly remained after preservation in alcohol which is found at the depth of 4 to 8 meters, on coral reef. Furthermore, the sexual reproductive cycle was described using standard methods. Gonads were removed and transferred to Bouin's fixative for four weeks and then processed according to standard embedding technique. To prevent the loss of tubule contents during embedding, the tubule sections, were cut well beyond the segment selected for sectioning. For each individual, six sections, each section with 5µm diameter by microtome were cut from tubules. These sections were first placed on gelatin coated slides (the gelatin was heated to 42°c) and then transferred to the oven at 37°c for one hour. This technique usually prevents the fragil tubules from breaking and the loss of gametes. The slides were stained with Eosin and Hematoxylin, and good resolution of the various cell types achieved.A second series of slides was stained with the Periodic Acid Schiff(PAS) to identify polysaccharides(glycogen). Monthly sampling was occurred.The sexual reproductive cycle was defined through the combined use of these criteria: Monthly percentages of the gonad stages for each sex, the monthly gonad index (GI) , given as the ratio of the wet gonad weight (G) to the dray weight (DW)and the monthly percentage of individuals that undetermined sex. The gonad consists of two tufts of tubules on which saccules develop. Gonadal development was classified into five stages: post spawning, recovery, growth, advanced growth, and mature stage that were adapted from the earlier studies of holothurians. Histological preparations showed that the sex of larger individuals could be identified by the presence of oogonia and young oocytes in females, and spermatogonic stages in males.The mean diameter of the tubules and gonadal mass follow annual cycles, increasing from late winter through spring, and dropping abruptly after spawning in the summer. Gametogenesis is generally a prolongate process and begins in March. By summer the ovarian tubules contain oocytes with diameter of 120-240 pm and the testicular tubules contain an abundance of spermatozoa (diameter 5-6 gm ).Following spawning the predominant activity within the spent tubules is phagocytosis of the residual gamets.The active phase of gametogenesis (March to July), coincides with an increasing photoperiod regim, and an accelerated gametogenesis occurs in July when temperature is high. Throughout the year, the gonad of Stichopus hermanni is larger in males than in females, and this is due to the number of tubules in the testis rather than to tubules length or diameter.