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1.
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   

2.
The helically coiled mid-Cretaceous family Turrilitidae Meek,1876 are abundant in late Albian and Cenomanian sediments ofEastern South Africa, including representatives of the generaPseudhelicoceras, Turrilites, Hypoturrilites, Ostlingocerasand Mariella, together with a new genus, Neostlingoceras (typespecies Turrilites carcitanensis Matheron, 1842).a Hypoturriliteshomoeomorph derived from Ostlingoceras. Twenty-two species andsubspecies are described, four of them new: Hypoturrilites crickisp. nov., Mariella (Mariella) acanthotuberculata sp. nov., Mariella(Mariella) oehlerti (Pervinquière) sulcata subsp. nov.and Mariella (Mariella) gallienii evoluta subsp. nov. The systematicpart.of the paper providesa basis for the discussion of thephylogeny, and some of the evolutionary trends shown by thefamily. An annotated synopsis of all genera and species referred tothe family is also included (Received 10 March 1977;  相似文献   

3.
The taxonomy of South African Siphonaria is reviewed. We concludethat nine species are valid. These are: S. anneae Tomlin, 1944;S. capensis Quoy & Gaimard, 1833; S. compressa Allanson,1959; S. concinna Sowerby, 1824; S. dayi Allanson, 1959; S.nigerrima Smith, 1903; S. oculus Krauss, 1848; S. serrata (Fischer,1807) and S. tenuicostulata Smith, 1903. Of these, Siphonarianigerrima Smith, 1903, has been incorrectly synonymized withSiphonaria carbo Hanley, 1858, which is not present on SouthAfrican shores. S. aspera Krauss, 1848 is reduced to a juniorsynonym of S. Serrata (Fischer, 1807). Shell characteristicsand mode of larval development are described for these nineSouth African species. All species deposit benthic egg massesand development may be either planktonic with swimming veligerlarvae (S. capensis, S. concinna and S. oculus) or direct, withcrawling larvae emerging from the eggs (S. anneae, S. compressa,S. dayi, S. nigerrima, S. serrata and S. tenuicostulata). (Received 20 November 1992; accepted 24 January 1994)  相似文献   

4.
Changing distribution patterns of T. pisana and C. virgata atcoastal sites around South Australia suggest T. pisana is replacingC. virgata in some areas Under laboratory conditions C. virgata exhibits reduced survivaland growth, is less active and feeds less when kept in the presenceof T. pisana adults and/or their mucus and excrement. If thearea of cooccurrence is large relative to the population size,C. virgata may be displaced to the less favourable habitats.No inhibition of the fecundity of C. virgata was seen. Bothspecies also depress feeding intraspecifically T. pisana also preys on C. virgata under some conditions, notnecessarily when food is limiting It is suggested that these mechanisms act within co-occurringpopulations of the species and result in the exclusion of C.virgata from some areas *Present address: 9 Torrens Ave, West Hindmarsh, South Auustralia,5007 (Received 1 November 1986; accepted 15 November 1987)  相似文献   

5.
Samples of the Antarctic limpet, Nacella concinna (Strebel,1908), were collected from four sites in the South Orkney Islandsand from Stromness in South Georgia during 1988. At three SouthOrkney sites, both littoral and sub-littoral samples of limpetswere taken. Shell dimensions were measured and littoral andsub-littoral limpets were shown to have significantly differentshell shapes. Foot and digestive gland tissues were subjectedto electrophoresis and five polymorphic loci {Es-1, lcd-1, lcd-2,Gpi, Got-1 and Pgm-1) and two monomorphic loci (Es-2 and Got-2)were scored. Genetic identities between littoral and sub-littoralforms and also between sites were calculated. At the loci scored,the littoral and sub-littoral forms were virtually identicaland this suggests that the shell shape differences between theforms are the result of environmentally induced phenotypic plasticity.However, significant genetic differences and some morphologicaldifferences were apparent between the sample of limpets fromSouth Georgia and all other sites. Genetic identity values suggestedthat the South Georgia and South Orkney N. concinna are geographicallyseparated populations of a single species rather than distinctsub-species. (Received 21 November 1990; accepted 17 April 1991)  相似文献   

6.
A NEW species of bivalve gastropod, Berthelinia burni, is describedfrom sediments of probably early Pliocene age from the AdelaidePlains Basin. * Geological Survey of South Australia; published with the permissionof the Director of Mines (Received 14 October 1960;  相似文献   

7.
Heleroceratid ammonites are abundant in the Upper Barremiansediments of Zululand, South Africa, and representatives ofthe genera Heteroceras, Colchidites and Paraimerites are describedbelow. This assemblage shows strong similarities to faunas knownfrom the Caucasus region of the USSR, a similarity that persistedinto the succeeding Aptian. This similarity presents somethingof a paradox, because the genera concerned are among the leasthydrodynamically streamlined of ammonites. Their distributionsuggests an open marine connection between the Mediterraneanparts of Tethys and the eastern coast of Africa, linked, inthe Barremian — early Aptian at least, to Patagonia. Theirwide distribution also supports the view that climatic gradientswerelow during the Barremian and that the climate was generallywarmer than at present. (Received 12 January 1983;  相似文献   

8.
This account reports on recruitment, growth and population structureof the macroherbivorous gastropod Helcion pellucidum (L.) onan exposed rocky shore in S.E. Ireland, with particular referenceto the pellucidum form. Recently settled Helcion spat were foundinitially on living crustose lithothamnia in pools and on openrock, on the lower shore, during February-April and subsequentlyrecruited to macro-algal fronds. By May they were found in abundanceon Mastocarpus stellatus and Laminaria spp. Helcion was markedlyseasonal in its occurrence on Mastocarpus, being most abundantduring May-August. A complementary pattern was evident on growingHimanthalia receptacles, with limpets abundant from July onwards.It is suggested that Helcion may migrate from Mastocarpus toHimanthalia as they grow. Data on growth rates are presentedfor Helcion in the various habitats studied. Growth rates werehighest on the Laminaria spp. (Received 21 February 1992; accepted 8 June 1992)  相似文献   

9.
Age composition and growth rates of the squid Loligo vulgaris(Lamark, 1797) were studied by examination of growth incrementswithin statohths of 419 specimens (mantle length, ML, rangingfrom 32 to 400 mm). The squid were obtained by monthly samplingfrom the catches of commercial trawls off southern Portugalbetween March and September, 1993 The total number of growthincrements in the mounted and ground statohths was counted usinga semi-automatic image analysis system. ML was significantlycorrelated with both the statolith length, TSL and the numberof increments, NI. The female statolith was slightly largerthan the male statolith for the same mantle size. Growth ratesof individuals showed high variability with an average estimatedat 34.6 mm month–1 for males and 33.5 mm month–1for females. Growth in length between 70 and 280 days was bestdescribed by a power function for both sexes. The growth indexof the statolith (TSL/NI) decreased with individual growth.This result may be related with the onset of sexual maturation.L. vulgaris hatched throughout the year with two distinct peaks,in spring which is the mam breeding period, and in autumn. Thelife cycle of the L. vulgaris population on the south Portugueseshelf was completed in one year *Present address for correspondence: Instituto de InvestigacionMariflas. Eduardo Cabello. 6 - 36208 VIGO. Spain (Received 28 November 1995; accepted 7 February 1996)  相似文献   

10.
11.
The ultrastructure of the pallial tentacles of seven speciesof patellid limpet is described. The tip of most of the tentaclesexamined bears a crown of long cilia, whereas the shaft of thetentacles has small tufts (5–10 µm diameter) ofshorter cilia. Sections through the ciliated tufts show themto be composed of several cells, each bearing cilia. The ciliacontain 5–7 central microtubules and therefore do nothave the conventional 9 + 2 arrangement of microtubules. Nerveprocesses run from the base of each ciliated cell to a nervebundle in the centre of the tentacle, suggesting a sensory function.Estimates of densities of ciliated tufts suggest that the territoriallimpets (Patella cochlear and P. longicosta) have the greaternumber of tufts. Electron dense plate-like structures are foundin the centre of the pallial tentacles of Patella cochlear,P. longicosta, P. granularis, P. barbara and Helcion pruinosus.Each plate is about 0.2 µm wide and is surrounded by adouble membrane. It is suggested that these may play a rolein scattering or reflecting light and thus form part of thedermal light sensing ability of these animals. (Received 26 January 1987;  相似文献   

12.
A systematic revision of the species of Benthobrookula Clarke,1961 from the Southwestern Atlantic Ocean was carried out. Theglobose protoconch, sculptured with a reticulate pattern, isrecognized as a diagnostic character for the genus. Benthobrookulaexquisita Clarke, 1961 and B. powelli Clarke, 1961 are redescribedand Cyclostrema calypso Melvill & Standen, 1912, Brookulapfefferi Powell, 1951 and Brookula strebeli Powell, 1951 areredescribed and allocated to Benthobrookula. Benthobrookulastrebeli is validated on the basis of the study of topotypicalspecimens. Two new species are described: Benthobrookula argentinafrom South Georgia and Benthobrookula paranaensis from off Brazil.A new allocation of Scalaria brevis d'Orbigny, 1840 to Benthobrookulais proposed. (Received 14 October 2004; accepted 20 May 2005)  相似文献   

13.
Aquatic snails from south western Zimbabwe belonging to theBulinus trunscatus/tropicus complex vary widely in shell formsuggesting that more than one taxon could be present. This possibilitywas investigated by making observations on snail samples from13 populations from the Plumtree area, in respect of allozymevariation (5 polymorphic loci), shell morphology (9 variables),copulatory organ and chromosome number. Comparative data wereobtained from snails from north western Zimbabwe identifieddefinitely as B. tropicus. Analysis of the genetic structurerevealed a high degree of polymorphism (P) ranging from 0.29–0.80among populations from Plumtree and expected heterozygosity(He) from 0.02–0.22. No enzymatic diagnostic loci werefound which could differentiate the different morphs or populationsand discriminant function analysis on the morphological datashowed an overlap of morphs among populations. Snails analyzedfor chromosome number were all diploid (2n = 36). Snails exposedto Schistosoma haematobium mira-cidia were all refractory. Thisinformation supports the view of a single species, B. tropicus,which is differentiated due to migration barriers and whereenvironmental variables might be implicated in the morphometricdivergence. (Received 31 July 1995; accepted 15 January 1998)  相似文献   

14.
AN ENERGY BUDGET FOR THE SOUTH AFRICAN ABALONE HALIOTIS MIDAE LINNAEUS   总被引:3,自引:0,他引:3  
Existing data on feeding, growth rate, fecundity, absorptionefficiency, respiration and excretion rates in the South Africanabalone Haliotis midae Linnaeus are converted to energy equivalentsand utilised to compile individual energy budgets. About 63%of the energy content of the food consumed (C) is lost as faeces(F) and a further 32% expended on respiration (R). Energy lossesin the form of ammonia excretion are negligible, accountingfor less than 1% of consumption. Some 5% of energy intake, or13% of absorbed ration (Ab) is thus available for growth andreproductive output (Pg & Pr). In juveniles (<100mm)this is all allocated towards somatic growth, while in adultsan increasing proportion of production is expended on reproductiveoutput. Although feeding, respiration and excretion rates allincrease with temperature the proportions of energy allocatedto the various components of the energy budget appear to beconsistent. Population energy budgets are calculated from densityand size distribution surveys at two study sites. At MarcusIsland, on the Cape west coast, the population has a standingstock of 82 g (wet flesh weight) m–2,.consumes about 3260KJm–2y–1 algae and has a P/B ratio of 0.46, whereasat Cape Hangklip, on the Cape south coast, the population biomassis_133gm–2, consumes 8613KJm–2y–1 and hasa P/B ratio of 0.70. These figures indicate that a high proportionof kelp bed primary production is directly consumed by grazingabalone in areas where populations have not been reduced byhuman exploitation (Received 16 March 1987;  相似文献   

15.
A new genus of Assimineidae, Conassiminea, is described fromestuarine habitats in southeastern Australia (New South Wales,Tasmania and Victoria). Two new species, C. studderti and C.zheni, are included in the genus, the former being the typespecies. Conassiminea is distinct from all other assimineidgenera in two autapomorphies in the female reproductive system:the seminal receptacle has two ducts and the bursal duct isextremely wide. The phylogenetic relationships of the new genuswere examined using a morphological dataset. (Received 26 February 2005; accepted 22 April 2005)  相似文献   

16.
Boshoff, A.F., Palmer, N.G., Avery, G., Davies, R.A.G. & Jarvis, M.J.F. 1991. Biogeoraphical and toporaphical variation in the prey of the Black Eagle in the Cape Province, South Africa. Ostrich 62: 58–72.

Prey remains collected at or near Black Eagle Aquilu verreauxii nest sites in the Cape Province, South Africa, were analysed according to frequency of occurrence of prey scies in the samples. A total of 5748 prey individuals, collected from 73 sites, was analysed according to tree biome groups and four nest site types. The Rock Hyrax Procuvia capensis is the dominant prey species, but the eagles' diet sctrum vanestypes. The according to its availability. Indices of species richness and diversity of the prey are inverser correlated with the proportion of the prey contributed by P. capenis, which in turn is determined by topography and vegetation. Biome has a greater influence on the indices than has nest site type. The age structure of the P. capensis prey remains closely reflects the juvenile: sub- adult: adult ratios in the biomes and at the nest site tpes. hfedium-sized (aprox. 1–4,5 kg) pre is usually taken. Juvenile domestic small-stock (lambs ani goat kids) comprised onb 3,4% of the over, total.  相似文献   

17.
The distribution of six endemic Antarctic nudibranch speciesis described, using both published data and new results fromrecent expeditions to the Atlantic sector of the South PolarSea. Notaeolidia schmekelae Wägele, 1990 is restrictedto the Weddell Sea, and N. gigas Eliot, 1905 to the AntarcticPeninsula and the Scotia Arc. N. depressa Eliot, 1905 is theonly member of the family Notaeolidiidae Odhner, 1926 with acircumpolar distribution. Localities of Pseudotritonia quadrangularisThiele, 1912 and Telarma antarctica Odhner, 1934, are knownaround the Antarctic Continent, whereas Pseudotritonia gracilidensOdhner, 1944 was only collected at the Antarctic Peninsula.The biogeographical divisions, discussed by several authors,do not coincide in all aspects with the distribution patternsof the Nudibranchia. According to my results, the AntarcticPeninsula forms a separate faunal zone, with transitional elementsof the High Antarctic and Subantarctic zone. South Georgia hasno endemic nudibranchs. (Received 30 March 1990; accepted 23 September 1990)  相似文献   

18.
A new ovoviviparous littorinid gastropod, Tectarius (Echininiopsis)niuensis, from Niue, west of the Cook Islands, is described.This is distinguished from the only other ovoviviparous memberof the genus, T. (E.) viviparus (Rosewater, 1982) from the MarianaIslands, here redescribed in detail. The new species is remarkabletor its high-level habitat in the littoral fringe on wave-exposedkarstic limestone cliffs, for its variation in shell shape accordingto tidal level, shell colour polymorphism, calcified operculumand penis with a single mamilliform penial gland. In a cladisticanalysis of morphological characters, including single representativesof each of the three other subgenera of Tectarius (Tectarius,Echininus, Tectininus), these two ovoviviparous species appearas sister-taxa. This is confirmed by a molecular phylogeneticanalysis of the same species, based on the sequence of a portionof the 16S ribosomal RNA mitochondrial gene. Neither analysisunequivocally confirms the monophyly of Tectarius. The divergenceof DNA sequences within Tectarius suggests that the genus arosein the Upper Cretaceous, much earlier than the oldest (UpperEocene) fossils. Only 4 of the 175 species of Littorinidae areknown to be ovoviviparous (with brooding through metamorphosis)and the possible adaptive significance of this type of developmentis discussed. Hitherto, its rarity had been explained by earlyextinction of poorly-dispersed brooding taxa. However, ovoviviparitymay have persisted in Echininiopsis for at least 35 millionyears, and has not precluded colonization of islands 6300kmapart. (Received 17 September 1996; accepted 15 November 1996)  相似文献   

19.
Comparison of the size, shape and shell morphology in littoraland sub-littoral morphs of the Antarctic limpet Nacella concinnareveal differences in shell morphology which are enhanced bystructural anomalies within the shells of the two types. Infestationof sub-littoral shells by the conchocelis phase of an endolithicalga significantly affects shell density and total chlorophylllevels in the two shell morphs. The surface sculpture of sub-littoralshells is characterised by a series of grooves, the configurationof which closely resembles that of the radular teeth in N. concinna.Limpets utilise the available food supply within the shell matrixof other limpets by grazing the shell material. Epibiotic growthof calcareous algae prevent erosion and preserve underlyingshell layers. In severe cases, where protection is lacking,intraspecific shell grazing may remove parts of the shell exposingthe internal tissues. The Dominican Gull, Larus dominicanus, is a major shore predatorof both shell morphs. Gull middens contain both shell typesbut are dominated by the more accessible littoral shells. Comparisonof living populations and midden assemblages indicates thatsize and shape selection of prey occurs, with pear-shaped limpetsbetween 21 mm and 29 mm in length being taken preferentially. Apparent differences in shell form are induced by physical,biological and behavioural influences. Littoral animals arerobust in nature, resist avian pre-dation and are not extensivelygrazed whereas those of the sub-littoral are not subject tothe same degree of predatory attention but suffer a gradualdepletion of their shallower shell form through a combinationof algal infection and intraspecific shell grazing. (Received 21 February 1990; accepted 5 July 1990)  相似文献   

20.
One specimen of the sand-burrowing nudibranch Armina tigrinaRafinesque was collected from South Carolina in June. The specimendeposited a single egg mass of approximately 6500 white eggswhich developed into lecithotrophic veligers in 8 days at 23°C.Of the veligers which metamorphosed, 9 lived 4–5.5 months(i.e. the life cycle was subannual). Eight individuals reachedsexual maturity in about 80 days. Copulation began at a bodylength of 24 mm and oviposition at 28 mm. During the 1.5 monthegg-laying period, each individual laid 2–4 wavy egg masseswith 2000–7000 eggs per mass. Death followed oviposition.Average growth rate of fed and starved pre-ovipositional nudibranchswas 3.4% and 0.9% per day respectively. Growth rate of ovipositingspecimens was 0.6% or less per day. Based on average feedingrates, each nudibranch consumed approximately 1.6 g damp weightof Renilla reniformis (one small colony) between metamorphosisand egg laying and 6.1 g damp weight (about two average colonies)from egg laying to death. Feeding efficiency is presumably increasedby interlocking and abutting radular teeth. Egg diameters reportedfor Armina tigrina from South Carolina and Florida were 199µm and 82 µm respectively. This difference suggeststhe existence of two species of Armina or ne species with twogeographically separated developmental types. Current address: Marine Science Institute, Northeastern University,Nahant, Massachusetts 01908. U.S.A. (Received 10 April 1980;  相似文献   

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