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1.
The relationships between the shell height of the predatory gastropod Cryptonatica janthostoma and the shell length of its typical prey, the bivalve Ruditapes philippinarum, and the diameter of the borehole on the prey shell resulting from a successful attack of the predator were experimentally found and assessed statistically. The shell height of C. janthostoma calculated retrospectively from the borehole diameter using the obtained relationships was 17–52 mm. The prey of C. janthostoma are burrowing bivalves, whose populations are affected by the predator to a varying degree. In populations of medium-sized mollusks (R. philippinarum, Protothaca euglypta, P. jedoensis, and others), C. janthostoma feeds on mollusks larger than 7–10 mm; in species with a shell length greater than 100 mm (Callista brevisiphonata, Saxidomus purpuratus), it eats specimens of 10–58 mm. C. janthostoma apparently has no effect on populations of small-sized mollusks (Anisocorbula venusta) and mollusks with an active avoidance response (Clinocardium californiense).  相似文献   

2.
Fatty acid (FA) markers are used to trace predator–prey relationships in the marine environment. Soft corals contain tetracosapolyenoic acids (TPA), namely 24:5n-6 and 24:6n-3, which are considered as octocoral FA markers. The nudibranch mollusks are known to feed on soft corals. To check whether TPA are transferred from soft corals to nudibranch mollusks during their nutrition, we determined and compared FA compositions of total lipids of Tochuina tetraquetra and soft corals (Acanella sp., Anthomastus rylovi, Gersemia fruticosa, and Paragorgia arborea) collected together near the Kuril Islands (the depths of 80–550 m). FA compositions of T. tetraquetra, Acanella sp. and A. rylovi were described for the first time. In Acanella sp., G. fruticosa, A. rylovi, and P. arborea, the average contents of TPA were 6.5, 13.4, 5.9, and 12.0 % of total FAs, whereas the 24:5n-6/24:6n-3 ratio was 1.0, 1.4, 5.4, and 2.6, respectively. The high level of TPA (21.7 %) found in T. tetraquetra indicates that 24:5n-6 and 24:6n-3 are transferred from soft corals to the mollusks during their feeding and accumulated in mollusk tissues. The most possible feed source of the mollusk is suggested to be G. fruticosa and/or Acanella sp., because the 24:5n-6/24:6n-3 ratios in T. tetraquetra and these soft corals were similar. Thus, the TPA could be used as FA markers to estimate a proportion of soft corals in feeding of cold-water nudibranch mollusks.  相似文献   

3.
The U small nuclear RNA (U snRNA) genes comprise a multigene family and are required for splicing of pre-mRNA. In this paper, we aimed to study the chromosomal location of the U2 snRNA gene in Megaleporinus, Leporinus and Schizodon species, which constitute interesting models for the study of repetitive DNA and genomic evolution in fish once the group comprises species with and without heteromorphic sex chromosomes. The all six species showed 2n?=?54 chromosomes: Megaleporinus elongatus, Megaleporinus macrocephalus, Leporinus striatus, Leporinus friderici, Schizodon borelli and Schizodon isognathus. The U2 snDNA clusters were evident in only one medium-sized submetracentric pair in all analyzed species and this may represent a condition shared by Anostomidae family.  相似文献   

4.
The distribution and growth of the bivalve mollusk Protothaca euglypta in Peter the Great Bay and at the northern boundary of its area were investigated. It is shown that in some biotopes P. euglypta biomass reaches 1–2 kg/m2, which exceeds the estimated values of abundance obtained for most associated species of mollusks. It has been established that local variability of P. euglypta growth rates can be compared with latitudinal variability, and the life span increases from the southern part of the area towards its northern boundary. It has been concluded that P. euglypta occupies a more prominent position in the malacofauna of shallow waters in its abundance, than it was considered earlier.  相似文献   

5.
Syneches from Brazilian biome of Caatinga were studied, two new species are described, Syneches atratus sp. nov. and Syneches limeirai sp. nov., and three species, Syneches annulipes Bezzi, 1909, Syneches moraballi Smith, 1963, and Syneches rafaeli Ale-Rocha & Vieira, 2008, are recorded for the biome. An identification key for the species of Syneches from Caatinga biome is provided.  相似文献   

6.
Odoria (Meruliaceae, Basidiomycota) is described as a new genus established for the threatened old-growth forest polypore Phaeolus alborubescens that was previously discussed in Aurantiporus or Tyromyces. It is characterized by the annual pinkish white spongy basidiocarp with strong sweetish smell, turning pale brown when drying, and has a positive reaction with KOH solution, the lack of cystidia, and the monomitic hyphal system with clamped generative hyphae often covered with fine orange crystals. Multigene phylogenetic analyses based on a combined (5.8S–nucLSU–rpb1rpb2) and a single locus (nrITS) dataset place Odoria in Meruliaceae (Phlebioid clade), close to Crustodontia, Sarcodontia, Luteoporia, and Phlebiporia. Molecular as well as anatomical study of the old type specimen of P. alborubescens is also provided.  相似文献   

7.
One hundred and four strains of heterotrophic bacteria have been isolated and characterized from two species of bivalve mollusks cultivated in the Gulf of Nha Trang (Vietnam) and from the water of a mariculture farm. The isolates have been identified on the basis of morphological, physiological, biochemical, and chemotaxonomic properties, as well as by the content of G+C bases in DNA. In the microflora of mollusks, Vibrio alginolyticus was predominant; the pathogenic species V. harveyi and V. splendidus were found as well. Staphylococci and bacilli occupied the second place in abundance after vibrios. In addition, coryneforms and enterobacteria, as well as Pseudomonas spp. and Pseudoalteromonas spp., were revealed. The composition of the water microflora was more diverse as compared with the microflora of mollusks. In the water, Bacillus spp., Vibrio spp., and Pseudomonas spp. were predominant. Brevibacterium spp. and other coryneform bacteria, as well as enterobacteria, occurred in significant amounts. In addition, Pseudoalteromonas spp., Marinococcus sp., Halobacillus sp., Shewanella sp., Sulfitobacter sp., and bacteria of the CFB cluster were noticed. The presence of pathogenic and conditionally pathogenic bacterial species in the water and mollusks is probably the reason for the high death rate of cultivated animals at the mariculture farm.  相似文献   

8.
A comparative analysis of the intestinal microbiomes of some representatives of the Lake Baikal endemic family Comephoridae—the big oilfish Comephorus baicalensis (Pallas, 1776) and the little oilfish C. dybowski (Korotneff, 1904)—has been performed for the first time. The phylotype Akkermansia (phylum Verrucomicrobia) was detected in the C. dybowski microbiome, while Alistipes, Bacteroides, Chryseobacterium, Prevotella (Bacteroidetes), and Peptoniphilus (Firmicutes), were found in the C. baicalensis microbiome. Their presence in the intestine is associated with an elevated lipid uptake or an increase in the human and animal body weight. It is hypothesized that these microorganisms are involved in the lipid metabolism of the oilfish and determine their morphophysiological adaptations to pelagic life.  相似文献   

9.
Although chondrichthyans are conspicuously present in shallow waters, many ecological aspects of neritic species in the Humboldt Current System remain unknown. This study provides a first assessment of the diet of seven commercially exploited and understudied sympatric chondrichthyans inhabiting nearshore habitats off the central coast of Peru: four stingrays (Hypanus dipterurus, Myliobatis peruvianus, M. chilensis, and Urotrygon chilensis), a guitarfish (Pseudobatos planiceps), a smooth-hound shark (Mustelus mento), and a chimaera (Callorhinchus callorynchus). A total of 166 stomachs were examined between 2012 and 2015 and prey items were pooled for the total of years for analysis. Although our analysis did not account for inter seasons variability, our results suggest diet partitioning among species, except for the stingrays’ group. A diet based on soft-bottom polychaetes and fish was shared by H. dipterurus, M. peruvianus, and M. chilensis, while soft-bottom polychaetes and crabs were more important in U. chilensis. The smooth-hound shark and guitarfish exhibited a diet dominated by crabs, and the chimaera consumed mainly hard-bottom mollusks. Foraging habitat estimations distinguished two main habitats of association: Benthic, including the stingray U. chilensis, the chimaera, and the smooth-hound shark; and benthic-demersal, including the guitarfish, and the rest of stingrays. A pattern of feeding specialization was observed for H. dipterurus, P. planiceps, and C. callorynchus. Preliminary trophic level estimations based on diet composition placed these species as secondary consumers. Intraspecific dietary variation was assessed for P. planiceps and H. dipterurus as their sampled sizes allowed meaningful comparisons. The diet of P. planiceps varied from small to large sizes but not for H. dipterurus. No differences were detected on diet composition between males and females in either species. Despite the limited temporal resolution, this study provides the first insights of chondrichthyans predatory activity, suggesting diet partitioning among the species of this assemblage in a nearshore habitat of the central coast of Peru. Enhancing the temporal resolution of this type of studies would improve our knowledge on trophic functioning in the Humboldt Current ecosystem.  相似文献   

10.
Morphological and molecular characterisation of echinostome specimens (Digenea: Echinostomatidae) recovered in one Anas platyrhynchos L. and one Cygnus atratus (Latham) (Anseriformes: Anatidae) from New Zealand revealed the presence of two known species, Echinostoma miyagawai Ishii, 1932 and Echinoparyphium ellisi (Johnston & Simpson, 1944) and two species new to science. Comparative morphological and phylogenetic analyses supported the distinct species status of Echinostoma novaezealandense n. sp. ex Branta canadensis (L.), A. platyrhynchos and C. atratus, and Echinoparyphium poulini n. sp. ex C. atratus. Echinostoma novaezealandense n. sp., a species of the “revolutum” species complex characterised by the possession of a head collar armed with 37 spines, keyed down to E. revolutum but was distinguished from the latter in having a much narrower body with almost parallel margins, longer oesophagus, wider cirrus-sac, larger seminal vesicle, much smaller ventral sucker, ovary, Mehlis’ gland and testes, more anteriorly located ovary and testes, and distinctly smaller eggs (81–87 × 42–53 vs 106–136 × 55–70 µm). This new species appears similar to Echinostoma acuticauda Nicoll, 1914 described in Australia but differs in having a longer forebody, more posteriorly located ovary and testes, and much smaller eggs (81–87 × 42–53 vs 112–126 × 63–75 µm). Echinoparyphium poulini n. sp. is differentiated from the four species of Echinoparyphium possessing 37 collar spines considered valid as follows: from E. chinensis Ku, Li & Chu, 1964 in having a much smaller body, four (vs five) angle spines and simple seminal vesicle (vs bipartite); from E. schulzi Matevosyan, 1951 in having a less robust body at a comparable body length, much smaller ventral sucker, ovary and testes, and longer but narrower eggs (87–109 × 50–59 vs 70–85 × 60–84 µm); and from the two smaller forms, E. serratum Howell, 1968 and E. aconiatum Dietz, 1909, in a number of additional metrical features correlated with body size and especially in the possession of much larger collar spines. Partial fragments of the mitochondrial nad1 and 28S rRNA genes were amplified for representative isolates of the four species and analysed together with sequences for Echinostoma spp. and Echinoparyphium spp. available on GenBank. Phylogenetic analyses based on the mitochondrial nad1 gene revealed congruence between the molecular data and species identification/delineation based on morphology; this was corroborated by the 28S rDNA sequence data.  相似文献   

11.
In this study, a total of 121 bacterial strains were isolated from the gastrointestinal tract of four teleostean species, namely striped snakehead (Channa striatus), striped dwarf catfish (Mystus vittatus), orangefin labeo (Labeo calbasu) and mrigal carp (Cirrhinus mrigala), among which 8 isolates showed promising antibacterial activity against four potential fish pathogens, Aeromonas hydrophila, Aeromonas salmonicida, Aeromonas sobria and Pseudomonas fluorescens and were non-hemolytic. The isolates were further screened in response to fish bile tolerance and extracellular digestive enzyme activity. Two bacterial strains MVF1 and MVH7 showed highest tolerance and extracellular enzymes activities, and selected for further studies. Antagonistic activity of these two isolates was further confirmed by in vitro growth inhibition assay against four selected fish pathogens in liquid medium. Finally, these two bacterial strains MVF1 and MVH7 were selected as potential probiotic candidates and thus identification by partial 16S rRNA gene sequence analysis. The bacterial isolates MVF1 and MVH7 were identified as two strains of Bacillus sp.  相似文献   

12.
Phanerochaete velutina and the closely related species P. alnea, P. alnea subsp. lubrica, and P. rhodella are identified as distinct species based on morphological criteria and molecular analyses. Besides differences in macroscopic and microscopic basidiocarp features, the taxa differ in distribution and ITS sequence. Phanerochaete alnea is widely distributed in Eurasia and North America, whereas P. alnea subsp. lubrica is limited to the Pacific Coast of North America. Phanerochaete velutina is known from Eurasia and Alaska, and P. rhodella is found in North America only. Nomenclatural problems with the name Phanerochaete P. Karst. are discussed, and type specimens for Thelephora alnea Fr., the generic type of Phanerochaete, and Peniophora karstenii Massee are selected. Phanerochaete alnea, P. alnea subsp. lubrica, and P. velutina are described and illustrated. In addition, the synonymy of Phanerochaete robusta and P. aurantiobadia is confirmed.  相似文献   

13.
Discussions concerning the composition of the genus Parendacustes Chop., in particular, its subgenus Minizacla Gor., are continued. Eleven new taxa of this subgenus are described: P. trusmadi sp. n., P. mulu sp. n., P. brevispina sp. n., P. modispina sp. n., P. longispina sp. n., P. forficula sabah subsp. n., P. doloduo sp. n., P. buton sp. n., P. pallescens sp. n., P. kendari sp. n., and P. lindu sp. n. New data on P. makassari Gor. are also provided.  相似文献   

14.
The genus Pseudomonas is one of the most diverse and ecologically important groups of bacteria. Numerous representatives of the genus are found in microbial communities of all natural environments, including those closely associated with plants and animals. This ubiquitous distribution determines a necessity of their physiological and genetic adaptations. Molecular methods revealed that bacteria of the genus Pseudomonas were predominant in ulcerative lesions on the skin of Baikal yellowfin Cottocomephorus grewingkii (Dybowski, 1874). According to ribosomal phylogeny, cultivated Pseudomonas spp. isolated from both ulcerative lesions and the water column of Lake Baikal were grouped into the intrageneric cluster IG P. fluorescens. The topology of the phylogenetic tree based on the gene for outer membrane porin OprF generally coincided with that based on the 16S rRNA genes at the intrageneric level; however, it reflected ecological features of the strains of the genus Pseudomonas at the subgroup level. Screening of pathogenicity determinants detected the oprL, ecfX, fliC, and algD genes in the genomes of Pseudomonas spp. isolated from the ulcerative lesions of fish, whereas oprL and gyrB genes were determined in the strains isolated from the water column.  相似文献   

15.
New concepts of systematics and phylogeny of the Permian Inoceramus-like bivalve mollusks of the eastern part of the Boreal zone are discussed based on analysis of the group’s historical development. All taxa studied are referred to the family Kolymiidae Kusnezov, which is divided into two subfamilies, Kolymiinae and Atomodesmatinae. In the subfamily Kolymiinae, two new genera are described: Praekolymia with the type species P. archboldi sp. nov. and P. urbajtisae sp. nov., and Taimyrokolymia with the type species T. ustritskyi sp. nov. In the subfamily Atomodesmatinae, two new genera, Costatoaphanaia and Okhotodesma, are described. The development of the group is shown to be generally autochthonous with some invasions (genus Atomodesma and, probably, Trabeculatia) from extraboreal regions.  相似文献   

16.
Endophytic fungi (EPF) are an important contributor to fungal diversity. It is surmised that EPF colonizing plant roots have high diversity. This study aimed to alleviate the scarcity of information regarding EPF in tropical forests, by isolationg and identifying EPF from a tropical forests in Indonesia. Soils were collected from five forests: (1) Tectona grandis monoculture; (2) Swietenia macrophylla monoculture; (3) Gmelina sp., Artocarpus champeden, Dipterocarp mixed; (4) Dipterocarp primary; (5) Macaranga sp. secondary. Four trees (Calliandra calothyrsus, Paraserianthes falcataria, Sesbania grandiflora, and Cassia siamea) and three crops (Sorghum bicolor, Allium fistulosum, and Trifolium repens) were grown in the forest soils to trap EPF. EPF were isolated from roots and isolation rates were calculated. Based on the isolation rates, P. falcataria and S. bicolor were chosen and grown again in forest soils. EPF were isolated and identified by their rDNA ITS1 region. Twelve and 21 EPF were isolated from 250 roots of P. falcataria and 300 roots of S. bicolor, respectively. Identified EPF were from genera Acrocalymma, Fusarium, Tolypocladium, Penicillium, Talaromyces, Exophiala, Dictyosporium, Pseudochaetosphaeronema, Mariannaea, Trichoderma, and Mycoleptodiscus. Acrocalymma, Tolypocladium, Penicillium, Exophiala, Pseudochaetosphaeronema, Mariannaea, and Mycoleptodiscus spp. were isolated from only one forest. Fusarium, Talaromyces, and Trichoderma spp. were isolated from more than one forest. The numbers of EPF isolated from Gmelina sp., Artocarpus champeden, Dipterocarp mixed forest, and Macaranga sp. secondary forest were higher than those from other forests, suggesting that different plant species in forests affect the root EPF community.  相似文献   

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Morphological study of Alona protzi Hartwig, 1900, Alona phreatica Dumont, 1983 and Alona smirnovi Petkovski &; Flößner, 1972 reveals close affinities with Alona labrosa Vasiljeva &; Smirnov, 1969. We separate these four species from the polyphyletic Alona Baird, 1843 (Anomopoda: Chydoridae). United under Phreatalona gen. nov., these taxa share primitive features on the limbs, together with specializations to a rheic life mode. Phreatalona contains some of the only true hyporheic taxa within the Cladocera. Endemism in two ancient lakes (P. smirnovi and P. labrosa) and a preference for river sediments in Europe (P. phreatica and P. protzi) suggest a long isolation from typical littoral/benthic biotopes. We discuss close links with southern vicariant Nicsmirnovius, the position of these (hypo)rheic chydorids within the subfamily and their affinities with Acroperus. We remark an independent evolution of external (habitus, postabdomen) vs. internal (limb) morphology in the protzi-complex. Phreatalona is likely tertiary in origin, evolving from a littoral alonine adapting to rheic and finally hyporheic environments. Baikal endemic P. labrosa is likely the most primitive species of the genus. We discuss adaptations and evolution in the hyporheic and the effect on dispersal and biogeography of Phreatalona.  相似文献   

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