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1.
A new species of the genus Kinkeliniceras Buckman (K. oppelin. sp.) from the Upper Callovian (Jurassic) horizon of the HaboHill in Kutch is described and illustrated. The form is characterizedby Hubertoceras-like inner whorls Kinkeliniceras has been shown to range throughout the Callovian. (Received 17 July 1979;  相似文献   

2.
Malayomaorica malayomaorica is an important Upper Jurassic bivalvein the southern hemisphere: widely distributed in strata ofEarly - Middle Kimmeridgian age, it is a zone fossil of considerablepotential for regional biostratigraphic correlations. Its commonoccurrence in the Latady Formation of the Orville Coast, Antarctica,indicates that at least part of this stratigraphic unit hasa Kimmeridgian age. Although its precise taxonomic status remainsin some doubt, it would appear to be the earliest buchiid-likebivalve so far recorded from the southern hemisphere. Its verywide distribution around the margins of Gondwana is similarto that established for species of the Late Jurassic bivalvegenera Retroceramus, Buchia and Anopaea (Received 13 April 1981;  相似文献   

3.
The effect of light quality on the extension growth of vegetativeshoots and on the final size of their leaves was investigatedin plants of Lolium multiflorum, Sporobolus indicus and Paspalumdilatatum. Three experimental approaches were used, (a) redor far-red end-of-day irradiations of sunlight-grown plants,(b) different red/far-red ratios of white light in a growthroom and (c) sunlight enrichment with radiation of differentred/far-red ratios or with different amounts of far-red lightduring the photoperiod. Plants treated with end-of-day far-redor low red/far-red ratios throughout the photoperiod developedlonger leaves and, as a result, longer shoots. This effect wasmore marked in leaf sheaths than in blades. Tiller extensionand leaf sheath length increased with the amount of far-redadded to sunlight in a simple hyperbolic relationship. Theseresults show that vegetative grass shoots respond to light qualityin a way similar to internodes of dicotyledonous plants. Lolium multiflorum Lam., Sporobolus indicus (L.), Paspalum dilatatum (Poir.), leaf growth, tiller growth, photomorphogenesis  相似文献   

4.
Patelloida pygmaea (Dunker) and its closely allied species,P. heroldi (Dunker) and P. conulus (Dunker) have caused nomenclaturalconfusion because of their variable shell morphology and distinctivehabitats. According to current nomenclature, these species ofPatelloida have been synonymized and treated as one specieswith two ecological forms. Patelloida pygmaea lives on the shellof Crassostrea gigas (Ostreidae), P. pygmaea form heroldi occurson intertidal rocks on sheltered shores and P. pygmaea formconulus is found on the shell of Batillaria multiformis (Batillariidae).Their taxonomic relationships and possible species status are,however, unclear. Using two mitochondrial genes (fragments ofCOI and 16S ribosomal RNA; total 1192 sites), we analysed 88specimens of P. pygmaea, P. pygmaea form heroldi and P. pygmaeaform conulus from 37 localities in East Asia. In the resultingmolecular phylogenetic trees, the specimens of Patelloida fallinto four clades with high bootstrap probabilities; these cladescorrespond taxonomically to P. pygmaea, P. conulus, P. heroldiand a fourth previously unrecognized taxon, Patelloida ryukyuensisn. sp., described here. A minimum-spanning network for 29 uniquemitochondrial COI haplotypes obtained from 45 specimens in thesame bay in central Japan form three distinct clusters, consistingof P. pygmaea, P. conulus and P. heroldi, respectively. Thissuggests that reproductive isolation has been established betweeneach group. A detailed examination of radular and shell morphologiesof the four taxa clarifies the morphological distinction betweenthese species. The four species form a rather young clade inthe genus Patelloida that diverged during the Pliocene. Theyprovide an example of habitat segregation in a restricted marineenvironment. (Received 21 December 2004; accepted 11 March 2005)  相似文献   

5.
During October to December 1997, we trawled estuarine habitats in the Joseph Bonaparte Gulf (JBG) to determine the distribution of juvenile red-legged banana prawns, Penaeus indicus (H. Milne Edwards, 1837) and white banana prawns, Penaeus merguiensis (de Man, 1888). We made 229 beam-trawls at 185 sites, mostly over a 100-m path (3-min duration). A Global Positioning System (GPS) receiver was used to verify our location. During October to December 1998, we intensively resampled three of the rivers that were sampled in 1997 to confirm the gulf-wide distribution of P. indicus and P. merguiensis and to investigate the microhabitat use of P. indicus. We chose previously sampled and new sites in Forsyth Creek (eastern JBG), the Lyne River (Cambridge Gulf), and the Berkeley River (western JBG). We made 249 trawls at 21 sites, mostly over 100 m.Juvenile banana prawns were abundant in eastern JBG, Cambridge Gulf and western JBG. They were not abundant in southern JBG, although fewer trawls were made there, due to its inaccessibility. In eastern JBG and Cambridge Gulf, over 96% and 73% (respectively) of juvenile banana prawns were P. indicus and they were more abundant there than in the western JBG. Conversely, in the western JBG over 93% of the juvenile banana prawns were P. merguiensis and they were more abundant than in the eastern JBG and Cambridge Gulf. The Lyne River in the northwestern Cambridge Gulf seems to be the transition zone; both P. indicus and P. merguiensis are equally abundant.P. indicus are most abundant on the mangrove-lined muddy banks of waterways within mangrove forests, similar habitats to P. merguiensis. Within these habitats, they were most abundant in gutters and small creeks, rather than rivers and large creeks. Few P. indicus or P. merguiensis were caught in 100 m2 trawls undertaken midriver (on the channel bottom and on emergent banks), although these habitats may be only 100 m from the mangrove-lined habitats. In all creek and river habitats, both species are most catchable at low tide (irrespective of daylight or darkness) when they move out of the mangrove forests and accumulate in the remnant water bodies.The offshore fishery for P. indicus is in northwestern JBG in waters 50-80 m deep, about 300 and 200 km, respectively, from where juveniles are abundant in their extensive inshore habitats in east JBG and in Cambridge Gulf, demonstrating a geographical separation of the juvenile and adult phases. Postlarval P. indicus, spawned offshore, must use tides and currents to travel south and east to reach nursery habitats. Emigrant subadults must migrate north and west, across relatively shallow inshore sand substrates (30-40 m deep) to reach their offshore habitats.  相似文献   

6.
Based on WP2 plankton net samples collected monthly between1970 and 1982 at several inshore and offshore stations alongthe coast of Lebanon, a morphological and ecological study ofthe Corycaeidae was carried out. This family is representedby 11 species. These are as follows, in decreasing abundance:Farranula rostrata, Corycaeus brehmi, C. typicus, C. giesbrechti,C. ovalis, C. minimus, C. clausi, C. larus, C. flaccus, C. limbatusand C. furcifer. Corycaeus minimus indicus is recorded for thefirst time in the Mediterranean. The seasonal variations inabundance showed a maximum in spring (March-June), the timingof the peak being slightly different between the stations andaccording to the dominating species. Spatial distribution showedan eupelagic sub-superficial tendency for the majority of thespecies found. As far as the geographical distribution is concerned,the Corycaeidae of Lebanon belong, in general, to the Mediterraneanand temperate Atlantic planktonic fauna, with a certain subtropicalaffinity for some species, due to the effect of Indo-Pacificmigration through the Suez Canal to the Eastern MediterraneanBasin: C. minimus indicus is such a case.  相似文献   

7.
The experimental susceptibility of Portugala inchoata, Euomphalia(M.) brigantina, Ponentina ponentina, Hygromia (P.) cantabricacantabrica and Hygromia (P.) cantabrica covadongae to Neostrongyluslinearis larvae were studied for the first rime. The total numberof molluscs used in the infections was 207 and they were killedin series between day 6 and SO post-infection. In order to definethe suitability of the molluscs as intermediate hosts for thisparasite, the number of L-I that penetrated the foot and developedto L-I, L-Il and L-III has been taken into account, as wellas the first days on which the different stages were observed One way analysis of variance showed statistically significantdifferences for the penetration and development of the larvaeamong the species of molluscs examined Statistically significant differences concerning the susceptibilityof the adult and young examples of P. inchoata and E. (M.) brigantinato N. linearis were confirmed by using the chi-square test The most susceptible species of molluscs to N. linearis usingexperimental infections were in decreasing order: P. inchoata,E.(M.) brigantina, H. (P.). caniabrica covadongae, P. ponentinaand H. (P.) caniabrica cantabric *This work was supported, in partt, by both the C.A.I.C.Y.T.(Project number 142/83) and C.S.I.C. (211) (Received 12 March 1987;  相似文献   

8.
The anatomy of 4 species of pisiid clam sampled in Ethiopia,Zimbabwe and South Africa was studied. The new species Pisidiumethiopicum is described, including the Ethiopian form regardedearlier as a variety of P. casertanum (Poli). P. incomitatumKuiper is included in the genus Musculium as type species ofa new subgenus Pseudopisidium. Anatomical characters of PisidiumkenianumPreston and P. langleyanum Melvill & Ponsonby arealso discussed. (Received 22 March 1994; accepted 23 August 1994)  相似文献   

9.
S. P. Subramaniam 《Hydrobiologia》1990,208(1-2):111-122
The penaeid prawns are recruited in the sheltered sandy beaches and mangrove areas of Chwaka Bay (Zanzibar) at post-larval stage (7 mm). Year round incursions with a maximum during the warmer months of December to March were observed. February to March is considered as the peak recruitment period. Out of six species of penaeids represented in the area, Penaeus latisulcatus (75%) and Penaeus indicus (15%) were dominant. The recruitment pattern indicated greatest incursions of post-larvae with the flood spring tides of the night when the tidal flow is strong.The juvenile population of P. latisulcatus is distributed in those intertidal sandflats with a rich growth of seagrass and P. indicus in the muddy areas of mangrove forests. P. indicus showed affinity for euryhaline conditions, whereas P. latisulcatus showed no preference for lower salinity. Provision of food and shelter are considered as important factors for their nursery dependence. P. latisulcatus attained a size of 60–70 mm in five to six months and P. indicus 110–120 mm in six to eight months during their nursery phase. These juvenile penaeids were found to be omnivorous, feeding on animal products, plant material and detritus.The maturing P. latisulcatus emigrate back to the sea when they are about 65 mm, whereas P. indicus move out at about 120 mm. A positive correlation between post-larval recruitment and juvenile abundance was observed.  相似文献   

10.
The genus Anopaea represents a small but distinctive group ofinoceramid bivalves that apparently remained functionally endobyssate.The somewhat unusual morphology (for an inoceramid) probablyresults from structural modifications tofacilitate sedimentpenetration at a high angle and anchorage by an antero-ventralbyssus. Although never as common as thecontemporary genera Retroceramusand Inoceramus, Anopaea is now known from temperate bivalveassemblages in both the Northern and Southern Hemispheres. Itpersisted from the Late Jurassic (Tithonian) to the Early Cretaceous(Neocomian), and possibly even later. (Received 26 June 1980;  相似文献   

11.
The life cycles, biomass and secondary production of three sympatricfreshwater basommatophoran snails, Lymnaea palustris (MÜller),Physa fontinalis Linnaeus and Anisus rotundatus (Poiret) werestudied during two years in a freshwater ditch. L. palustrisexhibited an iteroparous life-cycle whereas the two other speciespresented a semelparous life-cycle, adults died just after oviposition.L. palustris secondary production (dry weight) value was higher(P = 11 298.4 mg 0.1 m–1 yr–1) than those of P.fontinalis (P = 846.3 mg 0.1 m–2 yr–1) and A. rotundatus(P = 1192 mg 0.1 m–2 yr–1). (Received 16 March 1992; accepted 30 June 1992)  相似文献   

12.
Polycera hedgpethi Marcus, 1964, previously known only fromthe Pacific coasts of California and Mexico, is recorded fromPlettenberg Bay, South Africa. The high degree of morphologicalconsistency betweeen Pacific and Indian Ocean material insuresthat they are conspecific. P. hedgpethi is readily distinguishablefrom P. capensis, the only other Polycera recorded from SouthAfrican waters. (Received 20 July 1980;  相似文献   

13.
The external morphology of soft parts of the rare Patella ferrugineaGmelin, 1791 is described, and its relationships with P. caerulea,P. rustica and P. ulys-siponensis are investigated on both morphologicaland electrophoretic grounds. Soft part morphology is a gooddiscriminative tool, but of little help in detecting affinities.Electrophoretic data on 19 presumptive loci suggest that P.rustica is the closest species to P. ferruginea, whereas P.caerulea and P. ulyssiponensis are clustered separately. Meanobserved heterozyg-osities arc higher in P. ferruginea and P.rustica. It is concluded that in case of subdivision of thegenus Patella L., 1758, P. ferruginea and P. rustica shouldbe placed together in the subgenus Patellastra Mon-terosato,1884. (Received 6 January 1993; accepted 23 February 1993)  相似文献   

14.
Three types of petrified filician rhizomes and their associatedpetioles and roots from the Rajmahal Hills, Bihar, India aredescribed. Two rhizomes possess protostelic vasculature withmesarch protoxylem elements and exarch protoxylem points. Theformer are gleicheniaceous while the latter is described asa schizaeaceous rhizome. The associated petioles possess typicalgleicheniaceous anatomy while the roots show variations in thestructure of epiblema and cortex. filician fossils, Jurassic, Actinostelopteris pakurense, Gleichenia sonajoriense, Solenostelopteris jurassica, Gleichenioamyelon diarcha, Filicoamyelon cryptogrammoides Filicoamyelon actinostachyoides  相似文献   

15.
A complete post-incisor upper dentition and a left mandible with P/3-M/3 of the proviverrine hyaenodontid (Creodonta: Mammalia)Paratritemnodon indicus, which was hitherto known by heavily worn P/3-M/3, are described from the uppermost Subathu Formation (Middle Eocene) of the Kalakot-Metka-Mohgala area, Rajauri District, Jammu and Kashmir.P. indicus is most closely related to the North American Early Eocene proviverrine,Tritemnodon; its relationships withProdissopsalis from the Middle Eocene of Europe andPropterodon from the Middle to Late Eocene of China are also close. In the Kalakot Eocene vertebrate community of the Subathu vertebrate bioprovince,P. indicus is the only land dwelling carnivorous mammal against more than 20 species of herbivorous mammals, a majority of which are larger than it. This is viewed as an imbalance in trie community and it reflects an immaturity of the ecosystem supporting the fauna. The scarcity of carnivore remains in the Kalakot mammalian fauna is not an artifact.  相似文献   

16.
A population of Pseudotachea litturata (Pfeiffer, 1851) fromTarifa (Càdiz, Spain) has been studied. The morphologicalresults are compared with those from P. splendida, Iberus gualtierianus,I. alonensis, I. marmoralus, I. guiraoanus and four speciesof the genus Cepaea using, as an exploratory method, the Wagnerparsimony procedure and 18 characters of the shell, genitalsystem and karyotype have been analysed. According to this methodit seems that the taxonomical position of P. litturata in thegenus Pseudotachea is confirmed, and agrees with the phylogeneticalrelationships in this group of species. The genus Cepaea seemsto be well established, although two species groups can be distinguished:C. nemoralis—C. hortensis and C. syluatica—C. vindobonensis.These differ mainly in chromosome number, diverticulum lengthand degree of shell polymorphism. Although the present resultsdo not allow us to clarify the current taxonomical problemswithin the genus Iberus, the species studied seem to belongto a natural group (Received 15 September 1987; accepted 1 January 1988)  相似文献   

17.
Large cemented bivalves, previously regarded as oysters, encrustMiddle Jurassic hardgrounds in Southern England, Normandy andBurgundy. Well preserved specimens show auricles and a largeanterior byssal notch indicating that they are, in fact, theright valves of pectinids, apparently assignable to the genusEopecten Douvillé, 1897. Specimens removed from the substratedemonstrate that a prolonged early byssally-attached stage wasfollowed by attachment by cementation. Previously, the lifehabit of Eopecien has been regarded as enigmatic, interpretationshaving been hampered by the museum record of Eopecten whichis remarkably poor in large right valves. Our specimens suggestthat facultative cementation of adults may have been a commonhabit in the genus. (Received 7 May 1992; accepted 30 June 1992)  相似文献   

18.
The spermatozoa of Patelloida profunda albonotata, P. saccharina,P. pygmaea and Nipponacmaea schrenkii (Lottiidae) are describedby transmission electron microscopy. All have ect-aquasperm,typical of invertebrates using external fertilization. The spermof all four species have a cylindrical nucleus (length: breadth> 4: 1 in P. p. albonotata and P. saccharina; <4: 1 inP. pygmaea and N. schrenkii) which tapers towards the roundedanterior end. All have an acrosome with a posterior acrosomallobe which extends into the centre of the subacrosomal space.In P. p. albonotata and P. saccharina the acrosomal contentsare undifferentiated and the posterior lobe extends to the nucleus,being separated from it by flocculent material. In P. pygmaeathe acrosomal contents are differentiated, the lobe is relativelyshort and the subacrosomal space is filled with material witha fibrous appearance. The acrosome of N. schrenkii is undifferentiatedand the posterior lobe is no more than a bulge. The sperm ofP. p. albonotata and N. sacchrina have a small (0.25 µmlong) cytoplasmic collar which surrounds the axoneme anteriorlywhereas in P. pygmaea and N. schrenkii the cytoplasmic collaris longer (1 µm) and is swollen by an electron-dense vesicle.The composition and function of this vesicle is unknown. Thespermatozoa of Patelloida and Nipponacmaea have structural featureswhich are similar to sperm of the Lottiidae providing some supportfor the placement of these genera in the Lottiidae as proposedby Lindberg & Hedegaard (1996) and Sasaki & Okutani(1993) respectively. The similarities of the sperm of P. pygmaeato N.schrenkii raise some doubts about the tax-onomic statusof the former species. Spermiogenesis in all four species issimilar to that described for other Acmaeoidea and Patelloidea.In P. pygmaea and N. schrenkii, however, in addition to theacrosomal vesicle, the Golgi body produces a number of electron-densevesicles which fuse and eventually form a single vesicle inthe collar of the mid-piece. (Received 24 October 1996; accepted 10 February 1997)  相似文献   

19.
20.
POTAMOPYRGUS ANTIPODARUM--A MOLLUSCAN COLONISER OF EUROPE AND AUSTRALIA   总被引:1,自引:0,他引:1  
The hydrobiid gastropod genus Potamopyrgus is shown to be representedin Australia by the New Zealand species P. antipodarum (Gray).It is widely distributed in south eastern Australia and Tasmaniafollowing its introduction about the middle of the last century.The Australian populations of Potamopyrgus were known, incorrectly,as P. niger, because of a misinterpretation of Paludina nigraQuoy & Gai-mard, 1835. Paludina nigra, here placed in thegenus Fluvidona, is redescribed and a neotype designated. Potamopyrgusantipodarum has also been introduced to Europe, where it isknown as P. jenkinsi (Smith) (Received 19 August 1987; accepted 16 December 1987)  相似文献   

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