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1.
New England Coelogynoporidae   总被引:1,自引:1,他引:0  
Eleven species of the proseriate turbellarian family Coelogynoporidae have been encountered between Cape Cod, Mass. and the southern shore-line of New Brunswick, Canada. The distributions of Coelogynopora schultzii, C. biarmata and Cirrifera cirrifera are reported. Four new species belonging to the genus Coelogynopora, one new species of Cirrifera and a species belonging to a new genus are described. Two species remain undescribed. Biological observations on a laboratory-reared colony of C. biarmata maintained since 1978 are reported.  相似文献   

2.
Summary

A temporary pool in a dry stream bed traversing Grootvloer Pan in the Northern Cape was inhabited by fifteen branchiopod and calanoid copepod crustacean species. There was an unusually high number of congeneric species in the pool; in the class Branchiopoda, five Streptocephalus species and four Daphnia species were collected. In addition, two species of the calanoid genus Metadiaptomus were identified. The high species richness was not related to habitat diversity, pool size or difference in body size of each species. Three species (Streptocephalus purcelli, S. gracilis and Metadiaptomus capensis) had previously been collected only from the winter-rainfall areas of the Cape. Episodic flooding in the Northern Cape in 1988 may have resulted in the unusual community in the Grootvloer temporary pool.  相似文献   

3.
Summary

Two incidences of mass mortality of fish were recorded in two saline waterbodies (Swartvlei estuary and Rondevlei) in the Wilderness National Park. Species affected were the Knysna seahorse (Hippocampus capensis) and longsnout pipefish (Syngnathus acus) in the Swartvlei estuary, and Cape stumpnose (Rhabdosargus holubi) and white steenbras (Lithognathus lithognathus) in Rondevlei. Comparison of water quality parameters during fish mortalities to past ranges and reported species tolerances indicated that the probable causes for the mortalities were high water temperature in the Swartvlei estuary, and low dissolved oxygen concentration in Rondevlei.  相似文献   

4.
GELDENHUYS, C. J., 1993. Reproductive biology and population structures of Podocarpus falcatus and P. latifolius in southern Cape forests This study concerns morphological differences of the fruit types of two Podocarpus species in relation to their different population recruitment rates. First, sampling data from the mixed evergreen forests of Gouna and Groenkop in the southern Cape, South Africa, were used to describe the population structures of the two species. Podocarpus falcatus is widely scattered at low density and has a low recruitment rate. Podocarpus latifolius is widespread and common at high density and has a high recruitment rate. Second, the morphology of their fruits and seeds was studied in relation to seed dispersal, predation and germination. The species represent the two basic ‘fruit’ types of the genus. Podocarpus falcatus produces a heavy fruit, but invests mostly in dispersal (with a yellow fleshy pulp or epimatium enclosing the seed) and protective tissue (stony shell or sclerotesta) and very little into endosperm food reserves for the embryo. Podocarpus latifolius produces a light fruit which is composed mainly of dispersal tissue (blackish-purple fleshy receptacle) with protective tissue (thin leathery epimatium without woody sclerotesta) and food reserves for the embryo. The structure of the P. falcatus fruit is related to adaptation for protection during seed dispersal by bats. The stony sclerotesta delays germination for about one year and thereby causes the exposure of the seed to high post-dispersal predation by rodents and bushpig. Seedling recruitment is low. In contrast birds and baboons eat the receptacle of the P. latifolius fruit and discard the seed undamaged. Less protective tissue is required. Seeds germinate within two to four months and recruitment is high. The structural differences of the two fruit types also have predictive value for the relative success of the different sections of the genus. Section Afrocarpus (to which P. falcatus belongs) and related sections have relatively restricted geographic distributions. Section Eupodocarpus (to which P. latifolius belongs) and related sections have wide distributions.  相似文献   

5.
The Cape region of South Africa is a hotspot of flowering plant biodiversity. However, the reasons why levels of diversity and endemism are so high remain obscure. Here, we reconstructed phylogenetic relationships among species in the genus Protea, which has its center of species richness and endemism in the Cape, but also extends through tropical Africa as far as Eritrea and Angola. Contrary to previous views, the Cape is identified as the ancestral area for the radiation of the extant lineages: most species in subtropical and tropical Africa are derived from a single invasion of that region. Moreover, diversification rates have been similar within and outside the Cape region. Migration out of the Cape has opened up vast areas, but those lineages have not diversified as extensively at fine spatial scales as lineages in the Cape. Therefore, higher net rates of diversification do not explain the high diversity and endemism of Protea in the Cape. Instead, understanding why the Cape is so diverse requires an explanation for how Cape species are able to diverge and persist at such small spatial scales.  相似文献   

6.
Aim The causes of geographical variation in species richness in clades that do not follow the latitudinal diversity gradient have rarely been investigated. Here, we examine spatial asymmetries of diversity in Gladiolus (Iridaceae), a large genus (> 260 species) that is present in two mediterranean climate biomes: the Cape of southern Africa (106 species) and the Mediterranean Basin (7 species). Despite convergence of climatic conditions between the two regions, the species density of Gladiolus is over one order of magnitude higher in the Cape than in the Mediterranean Basin. We investigate whether the diversity disparities observed in the genus are better explained by recent colonization of species‐poor areas (temporal hypothesis) or by differential rates of diversification (evolutionary hypothesis). Location Africa, Madagascar and Eurasia Methods We employ a recently developed Bayesian method for the estimation of diversification rates and a biogeographical optimization approach within a phylogenetic framework. Results In Gladiolus, the ‘diversity anomaly’ between the two Mediterranean climate regions cannot be explained solely by the time available for speciation in the Cape, but is also due to locally reduced rates of diversification in the Mediterranean Basin. Furthermore, high overall diversity in southern Africa stems from an ancient origin in the Cape allied with high rates of diversification in the summer‐rainfall region of the subcontinent. Main conclusions Both evolutionary and temporal hypotheses must be taken into account in order to explain the diversity anomaly between the Mediterranean Basin and the Cape. Our results suggest that regions at comparable latitudes and/or with similar climate may not converge in diversity levels due to heterogeneity of diversification rates and contrasting biogeographical histories.  相似文献   

7.
Lloyd, P., Craig, A.J.F.K., Hulley, P.E., Essop, M.F., Bloomer, P. & Crowe, T.M. 1997. Ecology and genetics of hybrid zones in the southern African Pycnonotus bulbul species complex. Ostrich 68 (2–4): 90–96.

The closely related Blackeyed Bulbul Pycnonotus barbatus, Cape Bulbul P. capensis and Redeyed Bulbul P. nigricans have parapatric to locally sympatric distributions within southern Africa. Extensive hybridization along narrow transition zones between each of the three species pairs is described in a region of the Eastern Cape province, South Africa. The transition zones coincide with ecotones between different vegetation types, which in turn follow escarpments or mountain ranges. The lack of population density depressions within the hybrid zones, together with the variability of the hybrids, suggests the hybrids are viable. Sharp step clines in various phenotypic characters are described across the P. barbatus/P. nigricans hybrid zone. A mtDNA analysis found evidence of possible introgression between P. barbatus and P. capensis. All eight P. barbatus x P. nigricans hybrids analysed possessed P. barbatus mtDNA, suggesting the existence of either positive assortative mating or strong directional selection, but our data are unable to distinguish which. Our results do not support the dynamic-equilibrium model, but are compatible with the bounded-hybrid-superiority model. We conclude that the maintenance of the parapatric distributions of the different taxa is due mainly to differences in environmentally-associated fitness between parental phenotypes or among parental and hybrid phenotypes along an ecotone, with the narrowness of the hybrid zones maintained by the steepness of the environmental gradients crossing them.  相似文献   

8.
Summary

This paper reviews historical and current ecological information on macrobenthos from the Mhlathuze Estuary before and after development of the Richards Bay Harbour. The fauna is described in terms of the potential influence of a change in freshwater inflow to the system and the requirements for the setting of an Ecological Reserve. Over 95% of the species recorded were primarily marine and to a lesser extent estuarine in origin. Fauna typical of sheltered, soft-bottomed marine environments inhabited the estuary, whereas estuarine fauna was limited to the canalised sections of the Mhlathuze River. Certain areas were characterised by opportunistic species indicative of disturbed or organically enriched sediments while others sustained a high diversity of more sensitive climax species, several of which are endemic to southern Africa. The majority of species belonged to the Class Polychaeta but the estuarine mudcrab Paratylodiplax blephariskios dominated the benthic biomass. The pre-feasibility stage of the Ecological Reserve Determination indicated that a reduction in freshwater input would negatively impact upon the already reduced estuarine component at the head of the estuary. Conversely, if freshwater flow to the estuary is augmented, sediment transport via the river could increase without there being an. improved catchment management policy in place.  相似文献   

9.
Evolutionary relationships in the widely distributed velvet worm Peripatopsis balfouri sensu lato species complex were examined using DNA sequence data, gross and SEM morphology. Sequence data were generated for the COI mtDNA and the 18S rRNA loci and analysed using a Bayesian inference approach, maximum likelihood and maximum parsimony. Phylogenetic analyses of the combined DNA sequence data revealed that Peripatopsis clavigera specimens from the southern Cape (clade 1) was sister to P. balfouri sensu lato specimens from the Cederberg Mountains (clade 2). Within the main P. balfouri sensu lato species complex, three addition clades could be discerned (clades 3, 4 and 5). The obligatory troglobitic species Peripatopsis alba was equidistant between the Cape Peninsula and adjacent interior (clade 3) and the two Boland and Hottentots Holland Mountains (clades 4 and 5). On the Cape Peninsula, P. stelliporata specimens nested among the sympatric P. balfouri sensu lato specimens. The Cape Peninsula specimens were sister to specimens from Jonkershoek site 1, Kogelberg and Simonsberg. Two Boland clades were retrieved, comprising Du Toit's Kloof, Bain's Kloof and Mitchell's Pass and sister (in clade 4) to specimens from the Boland and adjacent Hottentots Holland Mountains in clade 5. These results revealed complex biogeographic patterning in the P. balfouri sensu lato species complex. The presence of sympatric, yet genetically discrete species pairs at six of the sample localities (Du Toit's Kloof, Simonsberg, Jonkershoek sites 1 and 2, Kogelberg and Landroskop) suggests that there is reproductive isolation between the lineages. Divergence time estimations suggest a Miocene/Pliocene/Pleistocene cladogenesis. A taxonomic revision of the P. balfouri sensu lato species complex was undertaken to stabilize the taxonomy. P. clavigera is monophyletic and retained for the southern Cape specimens, P. balfouri sensu stricto is now confined to the Cape Peninsula and adjacent interior, while P. stelliporata is regarded as a junior synonym of the latter taxon, P. alba is endemic to the Wynberg Cave systems on the Cape Peninsula. Three novel species (Peripatopsis cederbergiensis, sp. n., Peripatopsis bolandi sp. n. and Peripatopsis purpureus, sp. n.) are described.  相似文献   

10.
The Somali warthog, Phacochoerus aethiopicus delamerei, is the surviving relative of the Cape warthog, P. a. aethiopicus, which formerly inhabited Cape Province but became extinct in the last century. It is only recently that these two subspecies of Phacochoerus aethiopicus have been restored to the status of a species – the ‘desert warthog’– distinct from the common warthog, P. africanus ( Grubb, 1985 ; Grubb & Oliver, 1991 ; Grubb, 1993 ). Mitochondrial DNA analysis has recently confirmed that the common and desert warthogs are two different and widely divergent species (Randi et al., unpublished). This preliminary study maps their distribution in the Horn of Africa, and discusses the significance of ecological barriers that limit these distributions. One hundred and thirty‐three skulls from 64 different localities in five countries – mostly from museum collections – were identified. New material was obtained from the field and reliable literature data were also recorded. Locality records suggest that the optimal habitats of desert warthog are low altitude arid lands. The two species may overlap locally in northern Somalia, northern and eastern Kenya and southern and south‐eastern Ethiopia, but the desert warthog's precise range is still not accurately established and basic data about its conservation status, ecology and behaviour are still very poor.  相似文献   

11.
Summary

Three new trechine species of the genus Pilosaphaenops Deuve & Tian, 2008, P. qianzhii n. sp. from cave Lubian Dong in Pingtang County, southern Guizhou Province, P. mengzhenae n. sp. and P. weiguofui n. sp. from cave Xia Dong in Nandan County, and cave Shenlong Gong in Huanjiang County respectively, northern Guangxi Zhuang Autonomous Region, are described and illustrated. A key to all known species of this genus is also provided.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:170C467F-5421-49AD-B1B1-091D8BD58B88  相似文献   

12.
Two new species of the genus Plectrocnemia Stephens, Plectrocnemia levanidovae, sp. n., from Sakhalin Island and the southern Kuril Islands, and Plectrocnemia martynovae, sp. n., from southern Primorye, are described and illustrated. The new species belong to the P. tortosa Group and are the sister species of P. tortosa Banks, from China, and P. appensata Mey, from Vietnam.  相似文献   

13.
All freshwater calanoids in southern Africa belong to the family Diaptomidae of which there are two subfamilies, the Paradiaptominae (Lovenula, Paradiaptomus and Metadiaptomus) and Diaptominae (Tropodiaptomus and Thermodiaptomus). The Paradiaptominae are endemic to Africa, while the Diaptominae have one endemic African genus Thermodiaptomus, and the other genus Tropodiaptomus, occurs in other parts of the world as well as Africa. Knowledge of distribution of the Diaptomidae has been hampered by incomplete taxonomic knowledge and lack of co-ordination of available information. Distribution patterns of 19 described species and 11 new species confirm that the majority of species have a limited distribution, and that the Paradiaptominae are arid-adapted and belong to temporary pool communities. Six species are endemic to coastal pans and vleis of the western and southern Cape Province. Only those species with a wider distribution have been recorded as colonising man-made lakes. The four Lovenula species are predators and often co-exist with a Metadiaptomus species as prey. Synapomorphies of widely separated species of the Paradiaptominae, provide interesting insights into how their evolution may have been governed by vicariance, dispersal and palaeoenvironments of the African continent.  相似文献   

14.
It has been assumed that species of the large African genus Protea have strong self‐incompatibility systems. However, this assumption was based largely on studies conducted on a clade of bird‐pollinated species that occur in the shrubby fynbos vegetation of the Cape region of southern Africa. To test whether self‐incompatibility occurs in a grassland/savanna Protea clade, which is largely insect‐pollinated, we performed controlled pollination experiments on four species, P. caffra, P. dracomontana, P. simplex and P. welwitschii. Although pollen–ovule ratios of all four species fall within the range for outcrossers, all four species are self‐compatible and capable of autonomous seed production. Using fluorescence microscopy, we found that self‐pollen tubes had the same probability of reaching ovules as cross‐pollen tubes. In the small tree P. caffra, selfed progeny had rates of germination and survivorship that were identical to those of crossed progeny. The grassland Protea spp. studied are likely to have mixed mating systems on account of being both visited by insects and capable of autonomous selfing. If one assumes previous reports of self‐incompatibility in Protea to be reliable, there have been at least five losses of self‐incompatibility and two gains of autonomous selfing in this genus. However, earlier studies in the genus were often methodologically flawed and a thorough re‐analysis of breeding systems in Protea is required. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 169 , 433–446.  相似文献   

15.
Increasing human pressure on the environment in the isolated Macaronesian island group of Cape Verde is threatening many endemic species with extinction. The status of Phoenix atlantica, the Cape Verde Island date palm, is one of the unresolved taxonomic issues not only of the archipelago’s flora but also in the genus Phoenix. We applied 15 nuclear microsatellite markers and one chloroplast minisatellite marker to individuals of Phoenix from the Cape Verde Islands, P. dactylifera, P. canariensis and P. sylvestris, in order to assess the taxonomic position of P. atlantica within the genus. Our analysis showed that P. atlantica is clearly distinct from its close relatives and that its closest relative is likely to be its nearest geographical neighbour, P. dactylifera. Comparable levels of genetic diversity were found in insular P. atlantica and continental P. dactylifera despite the large difference in geographic range size. Our findings highlight the importance of conserving the relatively fragmented and isolated populations of P. atlantica as one of only␣two endemic trees on the islands and emphasise the need for further studies into its evolution and relationship with P. dactylifera.  相似文献   

16.
Summary

This study aimed to determine the distribution and relative abundance of freshwater fish in the Addo Elephant National Park. A total of 1578 fish specimens of 12 species were collected during surveys carried out in the Sundays River and four tributaries during 1996 and 1997. The redfin minnow Pseudobarbus afer comprised 81.6% of the total catch. Length frequency analysis of P. afer populations indicated recent successful recruitment in several rivers. Differences between rivers in the concentrations of dissolved and suspended solids and pH are possible reasons for different species complements. These surveys show the distribution of P. afer and Barbus aeneus in the Eastern Cape Province to be wider than previously reported. Management action is required to minimise opportunities for further establishment and spread of alien and translocated fish species and to conserve indigenous fish assemblages within the Park.  相似文献   

17.
The Western Australian camaenid genera Plectorhagada and Strepsitaurus have morphological similarities and mutually exclusive ranges near Cape Range. Sequences of ctyochrome c oxidase subunit I (COI) and 16S mitochondrial DNA (mtDNA) genes confirmed that the two genera are genetically close sister clades. Targeted sampling showed that Strepsitaurus, which is confined to Cape Range, lies within a hole in the distribution of the more broadly distributed Plectorhagada that occurs on the coastal strip surrounding Cape Range. Species of the two genera meet at the transition between the rocky Cape Range and the sandier coastal areas, providing a rare example of the close replacement of genera. Within each genus, mtDNA sequences confirmed the monophyly and genetic distinctness of species, with few exceptions that show the need for additional work, and with the addition of three new species in the Cape Range area. As is typical of Australian camaenids, distributions of congeneric species are mutually exclusive, but in some cases close proximity is associated with contrasting habitats, such as gorge endemics versus the species on top of Cape Range. In sympatry, Strepsitaurus rugus (Cotton, 1951) and Strepsitaurus williami Solem, 1997 are separated by microhabitat. These local associations with habitat indicate that ecological differences, and not simply allopatric divergence, contribute to the lack of sympatry between closely related Australian camaenids. © 2015 The Linnean Society of London  相似文献   

18.
The endemic diversification of the Cape zone fauna and the phylogenetic relationships among the 30 species of the blister beetle genus Iselma are investigated. We analysed morphological, molecular (mtDNA 16S) and combined datasets of characters using a number of approaches (maximum parsimony, maximum likelihood, Bayesian inference analyses). We propose hypotheses of diversification times among taxa from molecular clock analyses. Morphological and molecular analyses produced similar results. According to maximum likelihood molecular studies, radiation within the genus Iselma occurred during the Pliocene and Pleistocene, roughly contemporaneously with the shift in African climate, vegetation and faunal assemblages. Two main lineages, one Namibian and one South African, separated c. 4.9 Ma. Within the South African lineage we identify two groups of endemic species, one in Little Karoo and one that extend towards southern Namaqualand. The remaining South African groups of species are spread through Namaqualand and the southwestern Cape area. These include several endemisms, with different times of diversification during the Pleistocene, probably related in part to glacial cycles. These endemisms are distributed in small areas of the following ecosystems: coastal Strandveld, Succulent Karoo and particularly Fynbos.  相似文献   

19.
The Mngazana Estuary has the third largest area of mangroves in South Africa (118 ha) and one of the main environmental threats is the cumulative effects of long term small scale harvesting from local communities. This study investigated the change in aerial cover of the mangrove forest over time and assessed the effect of harvesting on the microenvironment and the population structure of Rhizophora mucronata (preferred harvested species) in both harvested and non-harvested sites. In 1982 there were 150 ha of mangroves of all species and since then 32 ha (21%) of the forest area has been lost. Areas of the estuary where mangroves have been completely removed showed significant differences in sediment characteristics. Changes in population size, ratios of adult trees to juveniles (harvested sites—1:5.5, non-harvested sites 1:3.4) and significant differences in height structure are some of the indications that harvesting is affecting the mangrove populations. Results show that while it is necessary to suggest proposals aimed at the sustainable use of the Mngazana mangroves, it is equally important in the short-term to make available alternative sources of materials to replace mangrove poles for building. The formation of the Mngazana Mangrove Management Forum provides an ideal opportunity to drive Participatory Forest Management (PFM) but this would require scientific and management support. The data shown here will provide ecological information required for PFM.  相似文献   

20.
River networks of major drainages can form barriers that shape the phylogeography of freshwater organisms, particularly those with low dispersal capabilities. Freshwater crab species' distributions can be used to examine hydrological patterns to expose historical drainage interconnectivity. We used molecular sequence data (mitochondrial and nuclear DNA) and divergence time estimations to determine the phylogeography of the freshwater crab, Potamonautes perlatus sensu lato, from six drainage systems along the Cape Fold Mountains, South Africa. Two major clades were detected: clade 1 comprised two geographically discrete haploclades occurring in southern flowing drainages, whereas clade 2 included specimens from western flowing drainages. Divergence time estimations suggested a Pleistocene (c. 2.61 Mya) divergence of P. perlatus s.l. The Pleistocene was associated with arid conditions and drainage contractions. However, it is likely that during the mesic conditions of the Pleistocene, P. perlatus s.l. migrated and diverged into contemporary patterns. We conclude that three lineages are nested within P. perlatus s.l., two representing novel species. Potamonautes perlatus sensu stricto is confined to western flowing drainages. The two novel species both occurring in southern flowing drainages are described here: P otamonautes barbarai sp. nov. occurs in the Gamtoos and Gourits Rivers and P otamonautes barnardi sp. nov. in the Breede River. © 2014 The Linnean Society of London  相似文献   

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