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1.
Analysis of the genetic structure (11 loci) of helminth populations (Monogenea, Diclidophora ), parasites of two teleost species (Gadidae, Trisopterus luscus and T. minutus minulus ) which are sympatric in the Atlantic, revealed the existence of two species which were specific to each of the two hosts. A strong genetic similitude was found between one of these species ( Diclidophora luscae ), a parasite of T. luscus and a monogenean population parasitizing a third Gadidae ( Trisopterus minutus capelanus ) in the Mediterranean. These results led to a re-examinination of the evolutionary systematics of the three host taxa of the genus Trisopterus. Genetic analysis showed differences between the two subspecies T. minutus minutus (Atlantic) and T. minutus capelanus (Mediterranean) at eight of the 16 loci studied. However, there was no significant genetic divergence between T. luscus and T.m. capelanus. A new phyletic structure in the genus Trisopterus is proposed and the evolutionary trends within the Gadidae/Monogenea system are discussed.  相似文献   

2.
Genetic analysis of the four Trisopterus (Gadidae) taxa suggests that the interrelationships of the two morphs of poor cod ( T. minutus minutus in the Atlantic and T. minutus capelanus in the Mediterranean) should be reconsidered. The Mediterranean poor cod T. m. capelanus is more closely related to bib T. luscus than to the Atlantic poor cod, so the population structure in the Atlantic and Mediterranean poor cod must be considered separately. Among 635 Atlantic individuals there was some evidence of poor cod population differentiation (allele frequency heterogeneity test P <0·0005; F ST=0·0135, P ≤0·0005). Levels of genetic variation were similar to those reported for related gadoid species. Some differentiation was present on the Norwegian coast (samples from Trondheimsfjord) and between the Faeroe Islands (Faeroe Bank) and the adjacent European coastal location. In contrast no statistically significant population differentiation was evident in Mediterranean poor cod, but fewer samples and individuals were screened.  相似文献   

3.
A surveillance programme was initiated on the occurrence and distribution of viral haemorrhagic septicaemia virus (VHSV) in wild marine fish. Six research cruises were undertaken in an 18 mo period during 1997 and 1998, covering the North Sea, the Atlantic waters off the north and west coasts of Scotland and the Irish Sea. A total of 19,293 fish were sampled from 23 different species including cod, haddock, Norway pout, herring and sprat. Individual fish lengths were recorded and the fish were checked for lesions, haemorrhaging and other signs of disease. Pools of organ samples were taken for virus assay. The majority of fish sampled did not display clinical signs indicative of viral haemorrhagic septicaemia. A small number of cod were found with skin lesions and haddock with skin haemorrhaging. Of the 2081 organ and skin sample pools collected, 21 tested positive for VHSV by tissue culture and enzyme-linked immunosorbent assay. Seventeen of the isolates originated from Norway pout Trisopterus esmarkii, one from cod Gadus morhua (skin lesion), one from herring Clupea harengus, one from whiting Merlangius merlangus, and one from a previously unreported host species, poor cod Trisopterus minutus.  相似文献   

4.
Testis of the Teleostean fish Trisopterus minutus capelanus has been examined to study the organization of the seminiferous tubules and the ultrastructural features of the germ cells. The testis is shown to be composed of seminiferous tubules full of cells: only few of them have just a very narrow lumen. Each tubule is divided by thin septa of connective tissue in zones containing homogeneous cells; such an organization is confirmed by ultrastructural images showing groups of synchronously developing germ cells. By morphological characterization of the germ cells found in each zone, 6 maturation stages have been identified. During spermiogenesis, a progressive shrinkage of germ cells and a nuclear chromatin condensation have been observed. Intercellular bridges, homogeneously dispersed granules of glycogen and groups of mitochondria associated with dense granular material have been described. Such features are present in the earlier stages of spermiogenesis and are retained until the later stages of spermatid differentiation. The spermatozoon shows a lack of acrosome as in many other teleosts previously studied.  相似文献   

5.
The diets of five gadoid species in the northern North Sea are described: the cod, Gadus morhua (L.); haddock, Melanogrammus aeglefinus (L.); whiting, Merlangius merlangus (L.); saithe, Pollachius virens (L.); and the Norway pout, Trisopterus esmarkii (L.). The diet of each species was shown to be a gradual progression to different prey species as the predators increased in length. There were differences in the food taken by each species with respect to numbers, species and size. These differences in diet suggest that the degree of competition between pelagic O-group gadoids is not great.  相似文献   

6.
This is the first report of the myxosporean Ortholinea orientalis from Atlantic herring Clupea harrengus. It infects the kidney tubules and previously was known from Pacific herring Clupea pallasii and navaga Eleginus navaga in the White Sea and North Pacific Ocean. This is also the first report of the coccidian Eimeria raibauti from Norway pout Trisopterus esmarkii. It infects the epithelium of the pyloric ceca and previously was known only from poorcod Trisopterus minutus in the Mediterranean Sea. The new records are both from the northern North Sea.  相似文献   

7.
Abstract.  The species of Australimyza Harrison are revised and the saprophagous larvae are described for the first time. The phylogenetic analysis revealed two species groups and one ungrouped species. One species group is distributed in New Zealand and associated subantarctic islands; all other species occur in Australia. Four new species, A. glandulifera , A. kaikoura , A. mcalpinei and A. victoria , are described, A. anisotomae is synonymized with A. australensis and a neotype is designated for the latter species. A lectotype is designated for A. macquariensis .  相似文献   

8.
Winter samples totalling 2308 specimens of Trisopterus luscus (total length range: 13–36 cm) caught in northern Portugal were examined for infections with Lernaeocera lusci. Infection prevalence was of 42%, and infection intensity was 1.7 copepods per infected fish. Individual infection varied between 1 and 9 copepods per infected specimen; 30.6% of the fish had bilateral parasitosis. There was a significant correlation (P<0.01) between fish length and prevalence. Length-weight relationships of uninfected and infected fish were not significantly different (P > 0.05) and thus provide evidence that L. lusci has no effect on the condition of T. luscus in all the examined 1–cm size classes.  相似文献   

9.
The present study assessed condition of pouting ( Trisopterus luscus Linnaeus, 1758) in nursery areas and other coastal areas along the Portuguese coast using different indices. Condition factor Fulton's K, RNA : DNA ratio and total protein content were determined for 0-group pouting collected in three shallow nursery grounds. Adult pouting were sampled in 10 sites along the coast and Fulton's K, hepatosomatic index (HSI), total protein content and water content were determined as indicators of condition. For 0-group individuals, only total protein content showed significant differences among the sites, whereas in adults all the indices evaluated differed significantly among the sites. However, due to high RNA : DNA ratios it was considered that all investigated nursery areas provided suitable conditions for survival and rapid growth of early stages of T. luscus . Adult pouting were also considered to be in good physical and nutritional condition along the Portuguese coast, although better growth conditions seem to be provided in the warmer waters of southern Portugal, evidencing a latitudinal trend.  相似文献   

10.
The currently accepted type species of the genusTrichosporon Behrend isT. beigelii. This species has formerly been regarded as identical toT. cutaneum. However, these fungi are now known to represent separate species with different ecology. The first species described inTrichosporon wasT. ovoides, an agent of human white piedra. A neotype strain is designated for this species, while a lectotype strain is indicated forT. cutaneum. The nameT. beigelii is considered as doubtful and consequently cannot be maintained.  相似文献   

11.
Twenty-one species of Stylopoma Levinsen, 1909 are described and illustrated with scanning electron micrographs. S. spongites (Pallas, 1766), the type species, is redescribed from the neotype specimen and included here for completeness. A neotype specimen for S. duboisii (Audouin, 1826) and a lectotype specimen for S. viride (Thornely, 1905) are designated and 14 new species of Stylopoma are described from Indo-West Pacific material in the Recent bryozoan collections of the Natural History Museum, London.  相似文献   

12.
The diets and diel feeding behaviour of six O-group gadoid species are described, the cod Gadus morhua (L.), the haddock Melanogramus aeglefinus (L.), whiting Merlangius merlangus (L.), saithe Pollachius virens (L.), Norway pout Trisopterus esmarkii (L.) and the blue whiting Micromesistius poutassou (R.). There were differences, in the main food groups selected by each species with respect to the type, size and number. The main prey consumed did not vary with depth. Cod, saithe and Norway pout had only one period of feeding activity whereas haddock and whiting apparently had two. The diets of haddock and whiting varied in association with these two periods. It is suggested that the differences between the diets were the result of each species having a different feeding behaviour which reflects that adopted in adult life.  相似文献   

13.
An epidemiological survey was undertaken of anisakids in 139 specimens (length: 13.2-24.5 cm) of pouting or bib (Trisopterus luscus) captured off the coast of northern Spain in the Cantabrian Sea. Third-stage larvae of two species of nematodes, Anisakis larvae type I and Hysterothylacium aduncum, were isolated. One adult female H. aduncum was also detected in the intestine of one pouting. Total prevalence of anisakids was 88.5%. Hysterothylacium aduncum and Anisakis showed, respectively, prevalence of 87.8% and 22.3%, mean intensity of 19.7 and 3.5, and mean abundance of 17.3 and 0.8. Analysis of infection parameters as a function of host length revealed a much higher prevalence in pouting specimens with length < 20 cm (94.4% for H. aduncum; 28.0% for Anisakis) than in those with length > or = 20 cm (65.6% for H. aduncum; 3.1% for Anisakis). The high mean intensity of Anisakis in muscle of parasitized pouting (5.9) may pose human health risks, although these are minimized by eating only thoroughly cooked pouting, as is the custom in Spain.  相似文献   

14.
Cutaneous taste buds in gadoid fishes   总被引:6,自引:0,他引:6  
Cutaneous taste buds occurred on the head and fins in five species of juvenile gadoid fishes from the west of Scotland, but there were significant differences in their density between regions on the fish and between species for individual regions. The highest taste bud densities were recorded on the edge of the anterior naris flap, the barbel, pelvic fin rays, snout tip and upper lip. Cod Gadus morhua and poor cod Trisopterus minutus had significantly higher taste bud densities on the first two pelvic fin rays than the other species. This appears to correspond with their more benthic lifestyle, in which the pelvic fins are frequently trailed over the sea bed when searching for prey.  相似文献   

15.
Abstract. Investigation of the chromosomes has revealed a Helophorus species from Central and Eastern Europe, and West Siberia, here described as H.paraminutus sp.n., which often closely resembles minutus F., though some specimens are larger and resemble lapponicus Thomson. The chromosomes of paraminutus are clearly distinct from those of minutus but closely resemble those of lapponicus. In the laboratory first generation hybrids were obtained between minutus and paraminutus, lapponicus and paraminutus, and lapponicus and minutus, but in no case was it possible to breed from these hybrids. Thus there can be no doubt that these three species are distinct. Recognition of paraminutus as a distinct species, despite the fact that study of its morphology alone could suggest introgressive hybridization between lapponicus and minutus, requires the recognition of limbatus Motschulsky as a species separate from H. lapponicus and necessitates the revision of the Helophorus minutus group of species which, as here defined, includes minutus, paraminutus, hilaris Sharp, lapponicus, limbatus, mervensis Semenov, rinki Angus, fulgidicol-lis Motschulsky and asturiensis Kuwert. Types and synonymies are discussed, and a key to these species given. Two old, imperfectly known, names are discussed to clear them from the synonymy: granulans var. rufipennis Hubenthal is identified as brevipalpis Bedel, and a lectotype designated; H. griseus var. lateralis Dalla Torre is left as incertae sedis and is classed as a nomen oblitum.  相似文献   

16.
Abstract. The mealybug Trabutina mannipara (Hemprich & Ehrenberg, 1829) is described and illustrated, and a neotype female selected from topotypic material collected in the Sinai Peninsula. A lectotype female is designated for Trabutina palestina Bodenheimer (1927) which is shown to be a junior synonym of T.mannipara.  相似文献   

17.
The group of small poor cods and pouts from the genus Trisopterus, belonging to the Gadidae family, comprises four described benthopelagic species that occur across the North-eastern Atlantic, from the Baltic Sea to the coast of Morocco, and the Mediterranean. Here, we combined molecular data from mitochondrial (cytochrome b) and nuclear (rhodopsin) genes to confirm the taxonomic status of the described species and to disentangle the evolutionary history of the genus. Our analyses supported the monophyly of the genus Trisopterus and confirmed the recently described species Trisopterus capelanus. A relaxed molecular clock analysis estimated an Oligocene origin for the group (∼30 million years ago; mya) indicating this genus as one of the most ancestral within the Gadidae family. The closure and re-opening of the Strait of Gibraltar after the Messinian Salinity Crisis (MSC) probably triggered the speciation process that resulted in the recently described T. capelanus.  相似文献   

18.
测定并比较分析了真蝽属(Pentatoma)5种昆虫:褐真蝽P.semiannulata、斜纹真蝽P.illuminata、红足真蝽P.rufipes、H本真蝽P.japonica和金绿真蝽P.metallifera以及益蝽亚科2种外群种类(并蝽Pinthaeus humeralis和蠋蝽Arma custos)mtDNA—COII基因部分序列,依据分子数据建立了该5种昆虫的系统发育关系。结果显示,5种真蝽COII基因A T平均含量(73%)高丁弹尾目、缨尾目和直翅目昆虫,低于双翅目、鳞翅目及膜翅目昆虫,而与缨翅目的蓟马和半翅目的突角长蝽Oncopeltus fasciatus非常接近。系统发育结果显示,红足真蝽与日本真蝽亲缘关系最近,形成一个姊妹群,斜纹真蝽与金绿真蝽亲缘关系较近,也形成一个姊妹群,褐真蝽为较早分化的种类。  相似文献   

19.
Data are presented on the type-material representing the species described by Linnaeus in his genera Sphex, Chrysis, Vespa, Apis and Mutilla , The names here considered total 158; six are currently applied in the Hymenoptera Parasitica. Of the balance of 147, three are emendations and five are unavailable homonyms or names proposed in the synonymy of other species. Fifteen Linnaean names are here placed as synonyms. One name is attributed to an author other than Linnaeus, and live names remain species incertae sedis. The remainder, 118, are applied as valid names in die Hymenoptera Aculeata. Holotype specimens in London, Uppsala or Stockholm represent 60 names; 55 names are based on lectotype specimens of which 49 are here designated, two by other authors. One name is represented by a neotype specimen in Lund, and one by a lectotype figure. One non-aculeate species is based on syntypes. Specimens appear to be lost with respect to 25 names; three specimens in Uppsala may be the holotypes of a further three species.
Eight new combinations are made, and twelve new synonyms established; three further new combinations and three further new synonymies are suggested. A systematically arranged summary of species treated and of nomenclatural changes made is given. Nomenclatural changes affecting non-Linnaean names are included where relevant; lectotypes are designated for two non-Linnaean species.  相似文献   

20.
It is argued that an alleged lectotype of the name Epipactis leptochila (designated in 1981) is actually a neotype, as the published plate in question did not appear in print until 14 years after the protologue. A herbarium specimen at BM represents original material that was used by Godfery when describing the E. leptochila, and in all probability the same is true for the original watercolour painting (now deposited at the Natural History Museum, London) from which the published plate was eventually reproduced. Therefore, a part of the herbarium specimen is designated as lectotype.  相似文献   

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