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1.
A few species in the genus Grateloupia (Halymeniaceae,Rhodophyta) have been investigated in detail with respect to morphological observations and molecular analyses.In this study,the authors document the vegetative and reproductive structures of two new species of Grateloupia,G.dalianensis H.W.Wang et D.Zhao,sp.nov.and G.yinggehaiensis H.W.Wang et R.X.Luan,sp.nov.They both have the morphological character that carpogonial ampullae and auxiliary cell ampullae are the simple Grateloupia-type.The two species can be distinguished from other species of the genus by their distinctive morphological features respectively.Based on ribulose-1,5-bisphosphate carboxylase/oxygenase (rbcL) gene sequences,the phylogenetic tree obtained in the study indicated that they are both embedded within the Grateloupia clade.G.dalianensis clusters a subclade with G.asiatica,and G.yinggehaiensis forms a single monophyletic subclade with G.hawaiiana.  相似文献   

2.
调查了大亚湾海域13种石斑鱼(Epinephelus spp.)寄生单殖吸虫群落,结果发现有10种鱼感染单殖吸虫,占调查鱼种类的四分之三,检获单殖吸虫16种,隶属于3科5属,其中拟合片虫属(Pseudorhabdosynochus spp.)10种;除鞍带石斑(E.lanceolatus)和拟青石斑(E.fasciatomaculosus)外,8种鱼可分别感染3—7种单殖吸虫;感染单殖吸虫种类最多的是玳瑁石斑(E.quoyanus)达7种,次之是青石斑(E.awoara)和养殖的橙点石斑(E.bleekeri)均感染6种;各单殖吸虫种类中,感染强度最大的是拟合片虫(P.serrani))(棕点石斑,E.fuscoguttatus)128只/尾,次之是石斑拟合片虫(P.grouperi)(青石斑)62只/尾,接下来是斜带拟合片虫(P.coioidesis)(大斑石斑,E.macrospilos)59只/尾和杯阴拟合片虫(P.cupatus)(玳瑁石斑)49只/尾;平均密度最高的是棕点石斑上检获的拟合片虫128只/尾;在检获的16种单殖吸虫中,8种可分别寄生于2种或2种以上石斑鱼,石斑鳞盘虫(Diplectanum grouperi)和拟合片虫在6种石斑鱼上都能检获,符合广寄生单殖吸虫种特征。有5种鱼检查尾数5尾以上的,其中玳瑁石斑单殖吸虫感染率最高62.07%,其内群落的物种丰富度与宿主体长呈显著正相关。  相似文献   

3.
In a study of meiofauna polychaete from the Huanghai Sea, a previously undescribed species belonging to Hesionura has been found and described. The new species differs from the other species of the genus Hesinura mainly by the chaetation.  相似文献   

4.
The whale‐louse Scutocyamus antipodensis n.sp., ectoparasitic on Hector's dolphin, Cephalorhynchus hectori (van Beneden), is described and figured from material collected in Cloudy Bay, Cook Strait, New Zealand. Morphologically the new species is very close to S. parvus Lincoln & Hurley, the type and only other species of the genus, known only from the North Sea. However, the two species differ in the detailed structure and spinosity of the body and pereopods.  相似文献   

5.
A brief history of research into, and the fishery for, Cape hake is given. From twelve monthly surveys in 1972/73, abundance of the two species (Merluccius capensis and M. paradoxus) at depth was found to vary, larger individuals of both species being found deeper than the smaller ones. Off the Cape of Good Hope, M. capensis was never found deeper than 440 m, and there was significant species overlap between 150 and 440 m. M. paradoxus was numerically dominant except at the shallowest station sampled (150 m). Little overlap of mature specimens of each species was recorded. The research data were applied to commercial trawl statistics, revealing that M. capensis accounted for only 12,9 per cent by mass and 4,8 per cent by number of the commercially caught hake in the years 1955–1974. Such low percentages justify considering the Cape hake fishery as a single-species entity for the purposes of stock assessment and management.  相似文献   

6.
The ichthyofauna of the intermittently open Shellharbour Lagoon in southeastern Australia was sampled over 14 months to investigate factors influencing species composition. Zostera capricorni and bare sand habitats were sampled every two months with a fine-mesh seine. Of the 10 277 fish caught representing 19 families and 27 species, the most numerically dominant species were Pseudogobius olorum and Pseudomugil signifer. The most abundant economically important species were Acanthopagrus australis, Mugil cephalus and Myxus elongatus. Mean number of fish and species was significantly higher over Zostera than bare sand during months immediately after the estuary opened when juvenile marine fishes recruited, demonstrating the estuary's nursery function. In contrast to other intermittently open estuaries in Australia and South Africa, Shellharbour Lagoon's fish assemblage appears resilient to perturbation and does not undergo distinct seasonal variations. This may be a result of the estuary's short open phases providing less opportunity for marine fishes to enter. Perhaps more importantly, the less dramatic fluctuations in salinity between open and closed phases maintains salinity at a level intermediate of the tolerances of both marine and estuarine fishes.  相似文献   

7.
A new species of lanternshark, Etmopterus alphus (Squaliformes: Etmopteridae), is described from the south-western Indian Ocean. The new species resembles other members of the ‘Etmopterus lucifer’ clade in having linear rows of dermal denticles and most closely resembles E. molleri from the south-western Pacific. The new species is fairly common along the upper continental slopes off central Mozambique, at depths between 472 and 558?m, and is also found on the southern Madagascar Ridge in 650–792?m depth. It can be distinguished from other members of the E. lucifer clade by a combination of characteristics, including arrangement of flank and caudal markings, dimension of flank markings and shape, size and arrangement of dermal denticles along the body. Molecular analysis further supports the distinction of E. alphus from other members of the E. lucifer clade.  相似文献   

8.
The presence and the distribution of two cryptic sedentary gobies, Pomatoschistus microps and Pomatoschistus marmoratus, were investigated in several lagoons stretching along the Golfe du Lion, southern France Mediterranean coast, and Corsica. Pomatoschistus microps is the only sedentary Pomatoschistus species in two shallow lagoons with large variations of salinity and temperature. In contrast, P. marmoratus, another sedentary species, can be found preferentially in a deep salty lagoon with small salinity variations. Both species occur sympatrically in the Rhone Delta and hybridise, producing fertile offspring. Using allozymes, competition, linked to fitness, is invoked to explain the distribution pattern of these sibling species.  相似文献   

9.
Cricotopus van der Wulp and Paratrichocladius Santos Abreu are among the most common genera of Chironomidae found in fresh waters throughout New Zealand. Imago, pupa, and fourth (final) instar larva of Cricotopus hollyfordensis n. sp. are described, and the male imagines, pupae, and larvae of Cricotopus zealandicus Hutton and Para‐trichocladius pluriserialis Freeman are redescribed from new material. C. hollyfordensis n. sp. can be distinguished from other Cricotopus species by antennal ratio and absence of tibial and abdominal markings in the male imago; shape and form of the thoracic horn, distinctive abdominal spinule patterns and lateral setae in the pupa; and mentum and mandible characteristics in the larvae. The combination of tibial and abdominal markings of the male imago; thoracic horn and abdominal spinule patterns of the pupa; and mentum and mandible characteristics of the larva distinguish C. zealandicus from P. pluriserialis and all other New Zealand Cricotopus species. P. pluriserialis is distinguished from Cricotopus species by the presence of normal and erect dorsocentral setae in the adult; smooth thoracic horn and distinctive abdominal spinule patterns of the pupa; mentum and mandible characteristics, supra‐anal setae longer than 2–3 abdominal segment lengths, and abdominal setae simple, never in tufts, in the larva. C. hollyfordensis n. sp. has been recorded from a fast flowing mountain  相似文献   

10.
For 3 years aspects of the population dynamics, growth, and bioactivity (measure of biologically active metabolite biosynthesis) of the Demospongiae Latrunculia sp. nov. and Polymastia croceus (Kelly‐Borges & Bergquist) were examined on a subtidal reef on the Wellington south coast, New Zealand. For both species, survival of adult sponges was high in all seasons, whereas juvenile sponges had poor survival. Recruitment of Latrunculia sp. nov. occurred in all seasons indicating that this species is reproductively active throughout the year. P. croceus recruited mostly in autumn, supporting previous work that found the sponge to be reproductively active in summer and early autumn only. For both sponge species, growth rates varied greatly between individuals and were unaffected by initial sponge size within the range examined. Sponges generally grew during winter and spring as the water temperature rose, and shrank during summer and autumn as the water temperature fell. This growth pattern may relate to seasonal variation in food abundance, and for P. croceus it may result also from seasonal differences in reproductive investment. After 2 years, Latrunculia sp. nov. and P. croceus had on average, halved and doubled in size, respectively. Latrunculia sp. nov. showed a seasonal pattern of bioactivity, being most active in spring possibly to prevent the surface overgrowth of fouling organisms. P. croceus had no seasonal pattern of bioactivity, but individuals were either very active or inactive. The bioactive metabolites in both species possibly aid in competitive interactions and prevent predation and biofouling.  相似文献   

11.
Cold seeps have recently been discovered in the Nile deep‐sea fan (Eastern Mediterranean), and data regarding associated fauna are still scarce. In this study, two bivalve species associated with carbonate crusts and reduced sediment are identified based on sequence analysis of their 18S and 28S rRNA‐encoding genes, and associated bacterial symbioses are investigated using 16S rRNA gene sequencing and microscopy‐based approaches. The specimens are closely related to Myrtea spinifera and Thyasira flexuosa, two species previously documented at various depths from other regions but not yet reported from the Eastern Mediterranean. Both species harbour abundant gammaproteobacterial endosymbionts in specialized gill epithelial cells. The Myrtea‐associated bacterium is closely related to lucinid symbionts from both deep‐sea and coastal species, whereas the Thyasira‐associated bacterium is closely related to the symbiont of a T. flexuosa from coastal waters off the U.K. An epsilonproteobacterial sequence has also been identified in Thyasira which could correspond to a helicoid‐shaped morphotype observed by electron microscopy, but this was not confirmed using fluorescent in situ hybridization. Virus‐like particles were observed within some symbionts in Thyasira, mostly in bacteriocytes localized close to the ciliated zone of the gill filament. Overall, results indicate that very close relatives of shallow species M. spinifera and T. flexuosa occur at cold seeps in the Eastern Mediterranean and harbour chemoautotrophic symbioses similar to those found in their coastal relatives.  相似文献   

12.
Spores of a new species of Nematopsis have been found in the green‐lipped mussel Perna canaliculus Gmelin. This is the first record of a sporozoan parasite of a New Zealand shellfish.  相似文献   

13.
The small-scale distribution characteristics of three species of the anomuran genus Munida, namely Munida rutllanti, Munida intermedia and Munida tenuimana, have been studied on the lower shelf and upper-middle continental slope near the coasts of Tarragona and the Ebro delta region in the western Mediterranean. The differential bathymetric distribution showed that a fair degree of overlap exists between M. rutllanti and M. intermedia, with the former being mainly found at shallower depths. The size population structure of the three species showed that polymodality, as indicative of a longer life-span and of a higher degree of population structuring was more evident in the deeper-living species, whereas unimodality, as an indication of a recruitment dependent population, was more evident in the shallowest-occurring species. Geostatistics have been applied to determine the degree of spatial variability occurring in M. intermedia abundance, the better-sampled species. The Mantel test has been used to assess the significance of the overlap between the three species distributions as well as the relation between certain population parameters. A discussion on the population characteristics of M. rutllanti is made in relation with its expansion along the western Mediterranean in the last decades.  相似文献   

14.
Several species of Gastrotricha were found among samples of nematodes extracted from a sandy ocean beach, South Broulee beach, in southeastern Australia. One of these Gastrotricha turned out to be a species new to science which is described as Halichaetonotus australis sp. nov. in this study. Although the spines of the hydrofoil scales resemble those of the cosmopolitan H. aculifer, a distinctive feature of the new species is the presence of three prominent posterior dorsal spines. These are exaggerations of the keels found on the dorsal overlapping scales that cover the dorsal surfaces of the head, neck, and trunk. The spines are almost as long as the rami of the terminal furca. H. australis sp. nov. also resembles H. marivagus, but differs in lacking both a cephalion and hypostomion. Freeze drying is introduced as a preparation method for scanning electron microscopy of Gastrotricha.  相似文献   

15.
Two species of benthopelagic calanoid Copepoda, Neoscolecithrix cf. magna (Grice, 1972) and N. ornata n. sp., are described from the upper slope off North Cape, New Zealand. Neoscolecithrix ornata is distinguished from other species of Neoscolecithrix Canu, 1896 s.s. that have a female leg 5 terminal segment with 4 spines (2 terminal and 1 on each border) principally by the transverse row of long, fine spines on the female genital double somite; and by the more squat terminal segment of leg 5 (length/width ratio about 3.7). This is the second time Neoscolecithrix has been recorded from New Zealand. A new genus, Cenognatha n. gen., is distinguished from Neoscolecithrix principally because: rostrum short (bearing 2 filaments); mandibu‐lar gnathobase masticatory margin with slender dorsal spinulose seta; maxilla endite 1 with 5 well‐developed setae, endite 3 without brush‐like sensory seta, endopod usually with 3 long worm‐like sensory setae and 5 brush‐like setae; posterodistal border of basis of legs 1–3 without spines; distal segment of female leg 5 and its basis subequal in length; male leg 5 of similar lengths on both sides (styliform on right), endopod present at least on 1 side, 1‐segmented and spine‐like on right.  相似文献   

16.
Axiothella serrata n. sp. (Polychaeta: Maldanidae) is described and illustrated from intertidal sands of Porirua Harbour, New Zealand (41° 6′ S, 174° 52′ E). It has 22 setigerous segments, and lacks asetigerous preanal segments; the mid‐ventral anal cirrus is conspicuously lengthened. The species is compared with other Axiothella species. A. catalinia Hartman, 1969 is herein transferred to Maldanella.  相似文献   

17.
附着生物与钻孔生物的分布是随着外界环境因素的不同而异,一般都受到了温、盐、流等外界因素的影响.因此,合理布局试验点,是全面了解我国沿岸附着生物生态,系统地掌握生物学资料的关键.十几年来,为了满足国防和国民经济建设上的需要,我所及其他单位已对中国沿岸的附着生物和钻孔生物做了大量的试验和调查研究,仅东海沿岸,从长江口、舟山海区、石浦到福建沿岸就做了近20处的试验.  相似文献   

18.
Galaxias vulgaris Stokell is a totally freshwater fish species and the adults usually live a cryptic life under stones. The life history of this species, with special emphasis on its embryology, growth rate, and sex ratio, is described. Comparisons are made with other members of the family Galaxiidae, especially G. maculatus attenuatus  相似文献   

19.
The feeding patterns of 12 teleost species taken by demersal trawl from two areas of the Cape coast and which fed predominantly on benthic and epibenthic prey are described. Prey selection varied intraspecifically with growth. There was considerable overlap in prey taken by different predators, although the dominant food differed between the two coasts and according to habitat (soft substrata or hard reefs). Prey selection varied with depth, probably as a result of the influence of depth and other physical features on prey species distribution. Small crustaceans were taken by all the predators and constituted the single most important group, especially for small predators. Brachyurans were important as prey, particularly in those species inhabiting hard substrata. Fish were of minor importance as food, except in Chelidonichthys capensis, Malacocephalus laevis and Helicolenus dactylopterus. Commercially important species of fish and cephalopods were preyed on only occasionally. It appeared that prey were selected according to their abundance, size, behaviour and habitat use. The use of benthic and epibenthic prey constitutes an important pathway for energy to return from the benthos to the foodweb.  相似文献   

20.
Phytotoxicities of the herbicides, atrazine and linuron, were evaluated for two species of submersed vascular plants (Potamogeton perfoliatus, L. Myriophyllum spicatum, L.) which, until the late 1960s, had been abundant in Chesapeake Bay. Plants were grown in 50-liter laboratory microcosms, containing filtered estuarine water and sediments for a period of 5 weeks and then treated with atrazine or linuron at initial concentrations of 0, 5, 50, 100, 500 and 1000 gmg/liter. Plant responses were measured primarily in terms of apparent O2 production, P3, and above-ground biomass for 4 weeks post treatment. In general, at ≥ 50 gmg/liter there was a significant depression in Pa for both species and herbicides. However, M. spicatum appeared to be less sensitive, with a significant enhancement in Pa of this species at 5 gmg/liter, and linuron was slightly more effective than atrazine at reducing Pa for both species. Treatment effects on biomass generally paralleled those for Pa. In spite of relatively constant atrazine concentrations (84–89 % remaining at termination), both species exhibited evidence of photosynthetic recovery 2–3 weeks after treatment at concentrations ≤ 100 gmg/liter. Using an exponential dose-response model, I50 (concentration for 50 % photosynthetic inhibition), ranged from 45–117 gmg/liter for all experiments. In general, in situ concentrations of atrazine and linuron in Chesapeake Bay and its tributaries appear to be sufficient to result in small reductions in Pa (2–10%, estimated from dose-response model) during a typical growing season. While such effects may be important for the survival of otherwise stressed plant populations, they suggest that these herbicides, per se, were not the cause of the general decline in abundance of these plants.  相似文献   

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