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1.
Summary

A new species of haemogregarine was found in the fish Barbus sharpeyi (Cyprinidae): Haemogregarina majeedi n. sp. which is broadly oval to reniform and with a large, subterminal nucleus. It was found with one to two schizonts within the erythrocytes and erythroblasts which were shorter and broader than normal. This is the third haemogregarine described from fishes in Iraq.  相似文献   

2.
Climate change poses an unprecedented threat to biodiversity worldwide. Consequently, unrecognised taxa may not receive adequate conservation attention to survive. We used molecular and morphological data to address the challenge of species delimitation within the genus Schilbe. The presence or absence of an adipose fin and distribution based on east-flowing, conceivably faster-flowing, or west-flowing, probably more slow-flowing, river systems were considered. Distinctive geographic patterns in genetic variation within southern, eastern, and western African populations were revealed. Particularly, the South African population is distinct from those of Namibia, Botswana and Nigeria. No individuals with rudimentary adipose fins were found at any locality, but specimens from three localities either had or did not have adipose fins. These mixed occurrences are suspected to be a result of human interventions, and that the presence of rudimentary adipose fins in the east African species could be an adaptive feature that serves to stabilise these fish in faster currents. In addition, the genetic divergence observed among African silver catfish from geographically isolated river systems is conceivably the result of micro-evolutionary adaptive responses to different environmental conditions. Collectively, these results distinguish S. depressirostris from S. intermedius.  相似文献   

3.
The present study explored the diversity of Nannocharax within southern Africa by implementing three species delimitation methods for a data set consisting of 37 mitochondrial cytochrome oxidase subunit I sequences. Two unilocus coalescent methods, the General Mixed Yule Coalescent (GMYC) and the Bayesian implementation of the Poisson Tree Processes (bPTP), and a genetic distance method, the Automatic Barcode Gap Discovery (ABGD), were applied. Both GMYC and bPTP delimited the same operational taxonomic units (OTUs), revealing a higher diversity for the genus in the region than previously recognised, whereas the ABGD failed to delimit the same candidate species. All methods delimited two species groups, and these are supported based on colouration patterning and morphology; the Nannocharax multifasciatus and the Nannocharax macropterus species groups and the delimited OTUs were assigned to each. Two putative new species were identified, Nannocharax cf. lineostriatus “Okavango” from the Okavango River in Angola and N. cf. lineostriatus “Kwanza” from the Kwanza River system in Angola. The distribution of Nannocharax dageti was confirmed for the Upper Zambezi and extended to the Okavango system, and an identification key for the southern Africa Nannocharax species is provided.  相似文献   

4.
Brycon nattereri (Ostariophysi: Characiformes: Characidae), a threatened South American freshwater fish, occurs in the Paraná, Tocantins and São Francisco river basins in central Brazil. It is a middle-sized (up to 50 cm SL), omnivorous species, which occurs in swift, clear-water rivers with well-preserved riparian vegetation. Main threats to the species are water pollution, dam building, and deforestation.  相似文献   

5.
Paeonocanthus antarcticensis (Hewitt, 1965) is redescribed based on four specimens recovered from a deep-sea smelt, Bathylagus antarcticus Günther, collected in the Antarctic Ocean (65 degrees S, 139 degrees 59.6'E). Studies on the morphological variations of these four specimens plus comparison with the three documented specimens yielded that the sphyriid reported as P. antarcticensis from the goiter blacksmelt, Bathylagus euryops Goode & Bean, taken in the Northwest Atlantic Ocean is a different species. It is renamed Paeonocanthus hogansi n. sp.  相似文献   

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7.
Lake Urmiah is a large (total surface 4750–6100 km2 in recent times) thalassohaline hypersaline lake (150–180 g l–1 in the period 1994–1996), located in northwestern Iran. It is the habitat of the endemic Artemia urmiana. Over the period July 1994–January 1996 a sampling campaign was organized: 36 fixed sampling stations, distributed over the entire lake's area, were sampled weekly to determine water temperature, salinity and transparency. At each occasion a filter net was dragged over a distance of 400 m in the superficial water layer to assess the density and composition of the Artemia population. A more limited sampling campaign focused on the annual fluctuations in chlorophyll concentration and on the reproductive behaviour of the brine shrimp population. Several stages of brine shrimp survived during winter months (water temperature 3°C) at low densities. Compared to available data for the Great Salt Lake, USA, Lake Urmiah shows a low algal biomass and overall low Artemia density. The increasing grazing pressure of the developing brine shrimp population in spring seems to prevent the phytoplankton from reaching high blooming concentrations, and oviparity is the dominant reproductive mode throughout the reproductive season.  相似文献   

8.
Acanthocephalus amini n. sp. (Palaeacanthocephala: Echinorhynchidae) is described from the intestine of Cichlasoma urophthalmus (Günther) (Pisces: Cichlidae) collected in the Río Champotón, a river in Campeche State, Mexico. It is the fourth species of Acanthocephalus Koelreuther, 1771 described from North American freshwater fishes, although two other species are known from South America. The new species is distinguished from other members of Acanthocephalus by features of its trunk, which is small, clavate, slightly expanded medially and bluntly pointed posteriorly. It is further distinguished by having a cylindrical proboscis armed with 13–14 longitudinal rows of 11–12 stout hooks; the apical and medial proboscis hooks are almost uniform in size and shape, decreasing in size towards the base; the posteriormost hooks are smaller, straighter and more slender than the anterior and middle hooks; and the lateral rows of hooks are more widely spaced, forming a conspicuous longitudinal area devoid of hooks. Furthermore, the lemnisci are saccate and shorter than the proboscis receptacle; and the neck is very short with a thick collar of trunk tegument, which encircles the base of proboscis. In males, the testes are in the middle third of trunk, diagonal, spherical and small relative to the body size, and there are six clavate cement glands. In females, the uterus forms a conspicuous, elongate, cylindrical egg reservoir. The new species is most similar to Aalabamensis Amin & Williams, 1983, but can be distinguished by its swollen, clavate trunk, the largest proboscis hooks being present apically and medially, smaller testes, a shorter male reproductive system relative to body size and females with a prominent uterus. They have different hosts and geographical distribution. The new species can be differentiated from Brasacanthus sphoeroides Thatcher, 2001, a similar species in a monotypic echinorhynchid genus, because the latter is larger, has smaller proboscis hooks and its lemnisci are longer than the receptacle.  相似文献   

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10.
The ecology and taxonomy of the epilithic diatom flora of the Agnéby River, Ivory Coast were studied in 2012. Ten sites were investigated and diatoms were sampled on glass slides immersed for a period of 30 days during the wet and dry seasons. Physico-chemical parameters were measured at each site while sampling diatoms. Five taxa were largely dominant: Planothidium comperei CE Wetzel, N’Guessan and Tison-Rosebery, Eolimna minima (Grunow) Lange-Bertalot, Planothidium piaficum (JR Carter and Denny) CE Wetzel and Ector, Cocconeis schroederi Foged and Cocconeis scutellum var. parva (Grunow in Van Heurck) Cleve. Electrical conductivity, temperature, dissolved oxygen, nitrite and phosphorus were found to influence the distribution of taxa.  相似文献   

11.
Systematic Parasitology - Megalodoras uranoscopus (Eigenmann & Eigenmann) (Siluriformes, Doradidae) (the giant-talking catfish or the giant-raphael catfish), from the...  相似文献   

12.
Prolactin-releasing peptide2 (PrRP2) was administered intraperitoneally to male intertidal blenny Rhabdoblennius nitidus, a species with male uniparental care of eggs, to investigate the effect on their feeding activity. A significant inhibitory effect on appetite was observed in the breeding season, but not in the nonbreeding season. These results suggest that PrRP2 and PrRP2 receptors are more active during the breeding season. The presence of a mechanism to inhibit feeding activity while parents take care of their offspring may be important for the success of parental care.  相似文献   

13.
Summary Olpidiopsis antithamnionis n. sp. (Oomycetes, Olpidiopsidaceae) parasitic on Antithamnion floccosum (O. F. Müll.) Kleen (Rhodophyta, Ceramiaceae) is described from three sites in Newfoundland, Canada, and from culture.Axial cells of the main and determinate branches of the host are the primary sites of fungal attack, although tetrasporangia and rhizoidal cells are also susceptible. Successful re-infection of A. floccosum was achieved in the laboratory although A. boreale and the trailliella-phase of Bonnemaisonia hamifera, both occurring with A. floccosum in the field, were immune. Regeneration of the host cells was observed, a phenomenon not previously reported in the fungal parasitism of other filamentous benthic marine algae.Studies in Biology from Memorial University of Newfoundland No. 256.  相似文献   

14.
Matthias Waltert 《Ostrich》2013,84(1-2):295-299
Waltert, M. 2000. Forest management and the distribution of understorey birds in the Bossematié Forest, eastern Ivory Coast. Ostrich 71 (1 & 2): 295–299.

The Bossematié Forest, Eastern Ivory Coast, has repeatedly been logged but is now subject to rehabilitation carried out by the Ivorian SODEFOR (Societé de développement des forêts) in co-operation with the German GTZ (Gesellschaft GTZ Technische Zusammenarbeit). To estimate the conservation prospects of forest birds, the influence of selective cleaning, an applied forestry practice, on vegetation structure and on the understorey bird community was studied. Vertical vegetation coverage was described and mistnetting was camed out in two adjacent management zones, a 3-years-old treated plot and an untreated control plot. The understorey vegetation in the treated plot has been damaged by fallen midstorey trees. The treatment plot differed from the control plot mainly in forming a low, single-layered canopy, which is typical for early successional stages. The analysis of 810 captures shows clear differences in the bird communities: the number of individuals of so-called open-land species was significantly higher in the treated plot, whereas that of forest-interior species significantly decreased. The results are used for the adaptation of species lists for an existing monitoring program. This will show, whether the establishment of strict reserves and the spatial and temporal distribution of management activities can maintain populations of forest interior species in the Bossematik forest in the long run.  相似文献   

15.
Euryhaline Cichlid fish of the species Coptodon guineensis are present in different water holes situated in a dried depression in the desert in the extreme South of Morocco, the Sebkha of Imlili. A genetic survey of this population, using complete sequences of the ND2 gene (mtDNA) and sixteen microsatellite loci, revealed that the fish in the sebkha did not form a single population, but rather a metapopulation. This metapopulational structure may be regarded as good news from the point of view of the conservation of fish in the sebkha. Although small individual populations may have short, finite life spans, the metapopulation as a whole is more stable, because immigrants from one population are likely to re-colonize the habitat, left open by the extinction of another.  相似文献   

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17.
This is the first record of the genus Jenynsia in the High Andean Plateau (HAP). It has been found at elevations between 3400 and 3900 m in three endorreheic systems: Salar Antofalla, Antofagasta de la Sierra and El Peñón, northwestern Argentina, South America. This finding increases the number of known HAP fish genera to five. Furthermore, in contrast to the old Andean species-rich genus Orestias, the presence of Jenynsia obscura populations in young high-altitude, non-marine saline wetlands reported here supports a recent dispersal into the HAP.  相似文献   

18.
Thelohanellus bicornei n. sp. (Myxosporea, Bivalvulida) is described from gill of Labeo coubie (Rüppel, 1832) (Osteichthyen, Cyprinidae) in Burkina Faso, West Africa. The cysts are small and their length is 150 to 350 microns. White, linked together they are rounded shape. The spores are ovoids with smooth valvar surface. Their posterior end is rounded and their anterior part shows two "horns like" expansions. Spores measured 13.5 +/- 0.56 (13-14) microns in length and 8.43 +/- 0.49 (8-9) microns in width. Horns length is 1 to 1.5 microns long. Polar capsule is piriform, it's length is 7.24 +/- 0.45 microns and the width 3.75 +/- 0.32 microns. The polar filament formed 10 turns.  相似文献   

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