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1.
Environmental and internal control of seasonal growth in seaweeds   总被引:6,自引:2,他引:4  
Lüning  Klaus 《Hydrobiologia》1993,250(1):1-14
All 6 naupliar stages of Scutellidium hippolytes (Kröyer, 1863), belonging to Tisbidae are described. A key for the identification of the naupliar stages is given. Naupliar peculiarities are discussed in the light of phylogenetic affinities. The nauplii are compared with those of the tisbids Tisbe gracilis and Drescheriella glacialis.  相似文献   

2.
Triterpene glycosides are characteristic metabolites of sea cucumbers (Holothurioidea, Echinodermata). Majority of the glycosides belong to holostane type (lanostane derivatives with 18(20)-lactone). Carbohydrate chains of these glycosides contain xylose, glucose, quinovose, 3-O-methylglucose and 3-O-methyl sylose. During the last 5 years, main investigations were focused on holothurians belonging to the order Dendrochirotida collected in the North Pacific, North Atlantic, Antarctic and in subtropical waters. The glycosides of holothurians belonging to the order Aspidochirotida have also been studied. The most uncommon structural features of carbohydrate chains of new glycosides were: (1) the presence of quinovose as fifth terminal monosaccharide unit and the presence of two quinovose residues; (2) the presence of glucose instead of common xylose as fifth terminal monosaccharide unit; (3) trisaccharide carbohydrate chain; (4) the presence of two 3-O-methylxylose terminal monosaccharide units; (5) the presence of sulfate group at C-3 of quinovose residue. New glycosides without lactone or with 18(16)-lactone and having shortened side chains have also been isolated. The presence of 17α and 12α-hydroxyls, which are characteristic for glycosides from holothurians belonging to the family Holothuriidae (Aspidochirotida) in glycosides of dendrochirotids confirms parallel and relatively independent character of evolution of glycosides. All three families belonging to the order Aspidochirotida: Holothuriidae, Stichopodidae and Synallactidae have similar and parallel trends in evolution of the glycosides carbohydrate chains, namely from non-sulfated hexaosides to sulfated tetraosides. Sets of aglycones in glycosides from holothurians belonging to the genus Cucumaria (Cucumariidae, Dendrochirotida) are specific for each species. The carbohydrate chains are similar in all representatives of the genus Cucumaria.  相似文献   

3.
Recent morphology-based investigations of freshwater Arctic diatoms suggest that many species remain to be discovered, reflecting a unique polar flora. During a survey of the freshwater diatom flora of northern Billefjorden, including the Petuniabukta fjord region (Spitsbergen), several morphodemes belonging to the Achnanthidium minutissimum species complex were recorded. Molecular phylogenies based on rbcL, 28S and 18S sequences, including single cells from Canada and strains from Marion Island (sub-Antarctica) and GenBank revealed the presence of 12 distinct A. minutissimum complex lineages, of which three contained strains from Spitsbergen. One Arctic lineage is described as a new species. Achnanthidium digitatum sp. nov. is morphologically characterized by narrow, linear to only slightly lanceolate valves and usually two areolae per stria. The two remaining Arctic lineages are in need of a more complete morphological and molecular comparison with other representatives of the A. minutissimum complex to clarify their taxonomic identity. It is argued that implementation of molecular data in the taxonomy of Achnanthidium will be essential to solve the taxonomic problems associated with this group, eventually resulting in a better understanding of the biogeography and niche differentiation of different species belonging to the A. minutissimum complex. Ideally, this should be based on more variable genes than the currently widely used 18S, which does not have a species level resolution in the A. minutissimum complex.  相似文献   

4.
5.
Summary The genusGymnoascus Baranetzky is monographed and found to include five valid species including one previously recognized species,G. reessii, one new combination,G. johnstoni, two new species,G. longitrichus andG. corniculatus, and a species originally described as aGymnoascus but included inMyxotrichum since 1893,G. uncinatus. Twenty species previously described as belonging toGymnoascus are excluded from the genus or are considered as doubtful representatives.Supported in part by Botany Department Research Grant # 1344, University of California, Los Angeles, California.  相似文献   

6.
A series of three α‐ and three β‐fluorinated representatives of the family of cinnamate‐derived odorants (cinnamaldehyde ( 1 ), cinnamyl alcohol ( 2 ), and ethyl cinnamate ( 3 )) as used as fragrance ingredients is described. Olfactive evaluation shows that the fluorinated compounds exhibit a similar odor profile to their parent compounds, but the olfactive detection thresholds are clearly higher. In vitro evaluation of the skin sensitizing properties with three different assays indicates that α‐fluorination of Michael acceptor systems 1 and 3 slightly improves the skin sensitization profile. α‐Fluorocinnamyl alcohol 2b is a weaker skin sensitizer than cinnamyl alcohol 2a by in vitro tests and the fluorinated product drops below the sensitization threshold of the KeratinoSens® assay. On the other hand, β‐fluorination of compounds 1  –  3 results in highly reactive products which display a worsened in vitro skin sensitization profile.  相似文献   

7.
The mating systems operating in seven species of Marasmius collected recently in northern Thailand were determined. Marasmius cremeus belonging to sect. Sicci subsect. Siccini ser. Leonini, and Marasmius straminiceps belonging to sect. Marasmius subsect. Sicciformes are described as new species. Five members of sect. Marasmius were tetrapolar (bifactorial), viz. M. apatelius, M. guyanensis, M. nigrobrunneus, M. ruforotula, and M. straminiceps. Two members of sect. Sicci were bipolar (unifactorial), viz., M. corneri (syn. M. incarnatus) and M. cremeus. Our data support the hypothesis that the mating system is consistent within infrageneric taxa. The seven species that are herein described, illustrated, and compared with phenetically similar species represent the first reports for this genus in Thailand.  相似文献   

8.
Two new species of Eutarsopolipus Berlese, 1911 (Acari: Heterostigmatina: Podapolipidae), belonging to the myzus species group, are described from the subelytra of carabid beetles (Coleoptera: Carabidae) in Iran. Eutarsopolipus anichtchenkoi n. sp. was found on Pterostichus sp. and E. terricolae n. sp. on Scarites terricola Bonelli. This is the first record of the myzus species group from Asia. A key to the adult females of this species group worldwide is provided, and the distribution and host range of all representatives of the group are discussed.  相似文献   

9.
Two new dasycladalean algae are described from the Gosau Group of the Northern Calcareous Alps in Austria. The tiny spicules of Acicularia? weisswasserensis n. sp. were found in foraminiferal wacke- to packstones associated with rudist limestones of the Weisswasser locality (Middle Coniacian), Lower Austria. The small globulous Terquemella? microsphaera n. sp. occurs in marls to marly limestones of the Pletzachalm locality (Upper Turonian), Tyrol, and Russbach locality (Upper Santonian), Lower Austria. The Terquemella-Acicularia group requires taxonomic revision; the two forms described herein, however, are clearly distinct from other species, and belong to the smallest representatives of these genera. In addition, Acicularia? aff. magnapora Kuss and morphologically similar forms interpreted as gametophores of unknown larger dasycladales are described.  相似文献   

10.
Abstract: Diverse freshwater aquatic palynomorphs are present among rich terrestrial palynofloras from the upper part of the Potrerillos and Cacheuta formations outcropping in the Cuyana Basin at the southern extremity of the Precordillera of Argentina. The Potrerillos/Cacheuta sequence includes fluvial, deltaic and lacustrine facies deposited in the early Late Triassic fault‐bounded syn‐rift Cacheuta hemigraben. The phytoplankton described and illustrated consist of representatives of colonial chlorococcalean algae belonging to the Hydrodictyaceae (Plaesiodictyon) and Botryococcaceae (Botryococcus), a diverse group of Zygnemataceae zygospores, a freshwater dinoflagellate cyst (Bosedinia) and acritarchs (sphaeromorphs). Zygnematacean zygospores are represented by species of Gelasinicysta?, Lecaniella, Mougeotia, Ovoidites, Peltacystia and Schizocystia. Of these, Gelasinicysta? cuyanensis sp. nov. is newly described. Quantitative analysis of the palynofloras permits interpretation of changes in the local vegetation and phytoplankton communities controlled by changes in environmental setting. Two algal associations are recognized as belonging to different stages in the evolution of the basin. Diverse zygnematacean assemblages along with hydrodictyacean, botryococcacean and leiosphere/sphaeromorph algae are common in fluvial–deltaic environments of the upper part of the Potrerillos Formation and the lowermost part of the Cacheuta Formation. Higher in the sections (in the Cacheuta Formation) Botryococcus dominates, in association with amorphous kerogen, representing deposition in a relatively deep, quiet‐water, lacustrine environment where anoxic conditions prevailed. In the Cacheuta hemigraben the lacustrine shales have average TOC values of 4 per cent (locally reaching 20 per cent), with some terrigenous components (Type II/III kerogen), but dominant amorphous, algal‐like, organic matter (Type I/II kerogen). Oils derived from these source rocks are predominantly waxy.  相似文献   

11.
To evaluate the sectional classification in Carex, subgenus Carex, the ITS region of 117 species belonging to 32 sections was analyzed with Neighbor Joining (NJ) and Markov chain Monte Carlo (MCMC) methods. In our analyses (1) species of subgenus Indocarex appear as a statistically well supported group within subgenus Carex. (2) The representatives of sections Vesicariae, Hirtae, Pseudocypereae, Ceratocystis, Spirostachyae, Bicolores, Paniceae, Trachychlaenae, Scirpinae, Atratae and Albae group in statistically supported clades with higher support in MCMC than in NJ. (3) C. rariflora clusters with representatives of section Limosae, however only weakly supported. (4) Taxa of section Phacocystis are divided in two statistically supported subclusters that are closely related to a core group of section Hymenochlaenae. (5) Species of sections Montanae, Pachystylae, Digitatae, Phacocystis, Rhomboidales, Careyanae and Frigidae are segregated into two or more clusters each. (6) Five species of section Frigidae cluster together, whereas the seven others are in scattered positions. Based on these results, delimitation of sections is discussed.  相似文献   

12.
Parastenocypris goddeerisi n.sp. and P. achandii n.sp. are described from temporary habitats in Kerala, southern India. The morphology of both males and females is illustrated and the new species are compared to the known representatives of the genus. Stenocypris fernandoi Neale, described from Sri Lanka, is here referred to Parastenocypris.  相似文献   

13.
A new harpacticoid copepod species was found during a year round plankton survey in a shallow Antarctic bay. Both the dominant Calanoida and Cyclopoida and the often neglected Harpacticoida, their abundances in relation to sea-ice formation and decline in presence of Euphausia superba are regarded, in this study. Alteutha potter sp. n. (Peltidiidae) was collected in Potter Cove, King George Island, Antarctica. While its geographical region occurrence and planktonic life style are comparable to many of its congeners, morphological characters such as shape and setation of the maxilliped and the almost complete fusion of the baseoendopod and the exopod of the fifth leg in the female are described for the first time for this genus. Morphological peculiarities such as the lack, the deformation or fusion of setae on only one body side have been detected in several specimens. This copepod species is obviously sea-ice related. Its abundances in the plankton reached a maximum under the winter sea-ice. The year round population structure did not show very high variability whereas ovigerous females mostly occurred in spring and summer. Assuming different possible ecological strategies and environmental temperatures generation times between 46 and 77 days are calculated for A. potter sp. n. Handling editor: K. Martens  相似文献   

14.
From the Lower Cretaceous locality Khasurty, western Transbaikalia, a new genus and species, Rasnitsyrina culonga, gen. et sp. nov. are described in the family Perlariopseidae. R. desiliens (Sinitshenkova, 1987), originally described in the genus Karanemoura Sinitshenkova, 1987, is transferred to the new genus. Two new species belonging to recent families are described: Dimoula khasurtensis sp. nov. (Nemouridae) and Jurataenionema rohdendorfi sp. nov. (Taeniopterygidae). All new species are described from fossils of adults.  相似文献   

15.
Yo  Khand 《Hydrobiologia》2000,419(1):119-124
The Cretaceous and Tertiary development of Mongolian non-marine ostracod faunas is reviewed. During the Late Cretaceous and Early Palaeogene, representatives of the Cypridoidea were widespread and common, Cytheroidea less so and the Darwinuloidea comparatively rare. The evolutionary history of the subfamily Talicyprideinae is considered, with reference to the genera Talicypridea, Altanicypris, Khandiaand Bogdocypris. It is suggested that the extinct Talicyprideinae were related to the mid-Cretaceous to Recent subfamily Cypridinae (e.g. the genus Cypris), both belonging to the family Cyprididae. It is shown that early representatives of the Cyprididae, one of the most diverse non-marine cypridoidean families today, were present from Early Cretaceous onwards (e.g. Lycopterocypris, Mongolocypris), alongside the dominant Cretaceous cypridoideans, the Cyprideidae (e.g. Cypridea), which became extinct in the Palaeogene.  相似文献   

16.
We diagnose new subfossil specimens belonging to the extinct palaeopropithecid, Mesopropithecus,from several caves at the Ankarana massif in northern Madagascar. They include three partial crania with mandibles, and the first vertebrae, ribs, clavicle, pelvis, ulna, and hand and foot bones of Mesopropithecusever found. Several other postcranial elements are known for this northern variant of Mesopropithecusand for previously described species from central and southern Madagascar. The new materials cannot be accommodated in either currently recognized species of this genus and are,hereby, given the name Mesopropithecus dolichobrachion. M. dolichobrachionis the second new species of extinct subfossil lemur to be found in the caves of Ankarana. It is unlike the two previously described species of this genus primarily in its larger size, different limb proportions, and aspects of its long bone morphology. Most notable is the fact that this is the only species of Mesopropithecuswith the forelimb longer than the hind limb— hence the name, the “long-armed” Mesopropithecus.Various characteristics place M. dolichobrachionphenetically closest (of species belonging to Mesopropithecus)to Babakotia radofilai, Archaeoindris,and Palaeopropithecus.If these similarities are derived specializations rather than primitive for palaeopropithecids, a new generic name will be required.  相似文献   

17.
The Kutch region of western India (Gujarat State) is today arid to semiarid and characterised by mostly ephemeral streams which carry water during the monsoon. The uneven distribution of rainfall and disturbed topography are the result of climate change during the Cenozoic period. Two fossil woods, namely Bauhinium palaeomalabaricum Prakash and Prasad (Fabaceae) and Ebenoxylon indicum Ghosh and Kazmi (Ebenaceae), are described from Kutch in order to provide insights into the palaeovegetation and palaeoclimate. Because the modern representatives of the present and previously described taxa from the same horizon are thermophilic in nature and grow in evergreen to deciduous forests, a warm and humid climate is interpreted. Furthermore, the finding of some mangrove taxa in the assemblage indicates the lagoonal to intertidal environment at the time of deposition.  相似文献   

18.
A new species of the orchid genus Myoxanthus, M. oliviae, is described based on Peruvian material. The novelty resembles M. serripetalus from which it differs by the 7–8‐veined lateral sepals (versus 6‐ or 9‐veined), the petals contracted below the apex and expanded again into a sagittate apex (versus apex caudate) and entire lip middle lobe (versus fimbriate). The flowers of M. oliviae are pale brownish‐purple, internally intensively suffused with yellow, dark‐purple spotted. The new species grows among rocks at the elevation of 2700–3100 m a.s.l. A key to Peruvian Myoxanthus representatives is provided.  相似文献   

19.
Cytochrome b (Cyt-b) gene was sequenced for six flatfish species and compared with seven other species belonging to Pleuronectiformes. Monophyly of the family Pleuronectidae representatives was fine supported by bootstrap or other means in several sequence-based trees on Cyt-b gene data. Results revealed that synonymy must be accepted for Hippoglossoides elassodon, and H. robustus, as well as for Pseudopleuronectes yokohamae, and P. schrenki. This article was submitted by the authors in English.  相似文献   

20.
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