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1.
Ecomorphological theory predicts a match between an organism's environment and its locomotor abilities, such that animals function most effectively under the conditions they experience in nature. However, amphibious species must simultaneously optimize performance in two different habitats posing incompatible demands on locomotor morphology and physiology. This situation may generate a mismatch between environment and locomotor function, with performance optimized only for the more important habitat type; alternatively, selection may fine-tune locomotor abilities for both types of challenges. Two species of sea kraits in New Caledonia offer an opportunity to examine this question: Laticauda laticaudata is more highly aquatic than L. colubrina , and males are more terrestrial than females within each taxon. We examined an aspect of locomotor performance that is critical to coming ashore on steep-walled rocky islets: the ability to climb steep cliffs. We also measured the muscular strength of these animals, a character that is likely critical to climbing performance. Laticauda colubrina was heavier-bodied and stronger (even relative to its body mass) than the more aquatic L. laticaudata ; and within each species, males were heavier-bodied and stronger than females. The same patterns were evident in cliff-climbing ability. Thus, the ability of different species and sexes of sea kraits to climb steep cliffs correlates with their body shape even though these primarily aquatic animals use terrestrial habitats only rarely.  © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 85 , 433–441.  相似文献   

2.
The West Indian species Liabum oblanceolatum Urb. & Ekman was established on the basis of sterile young specimens represented by acaulescent herbs with rosulate leaves. However, these specimens have important traits that do not correspond to Liabum Adans. More than 90 genera of Asteraceae occur in Hispaniola (= Santo Domingo), but only 14 of them include species represented by acaulescent herbs with rosulate or grouped leaves at the base of the stem. From these genera, Chaptalia Vent. and Liabum are the most similar to the types of L. oblanceolatum . Habit, leaf arrangement, lamina shape, leaf margin, leaf surface, leaf margin intrasection, leaf venation, leaf pubescence, leaf trichomes, stomata and upper surface leaf cuticle were analysed in the type specimens of L. oblanceolatum and in species of Chaptalia and Liabum of Hispaniola. The vegetative trichomes are described in detail. The analysis reveals that the type specimens of L. oblanceolatum fit with all the vegetative traits of Chaptalia angustata Urb. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 150 , 479–486.  相似文献   

3.
The woodpecker genus Veniliornis comprises 12 species, all restricted to the New World tropics. The seemingly distantly related genus Picoides is broadly distributed in Eurasia and North America with two putative species, P. lignarius and P. mixtus , occurring in South America. The two genera are clearly distinct with respect to general plumage colouration and patterning as well as habitat utilization and thus traditionally have been placed in different tribes. Phylogenetic analyses of mtDNA sequences from the COI and cyt b genes indicated that both genera are reciprocally paraphyletic. The two South American species of Picoides belong to a clade comprising most species of Veniliornis , but V. fumigatus of Central and north-western South America belongs to a clade comprising species of Picoides . The mtDNA tree also indicated that Veniliornis is not closely related to the genus Piculus, as is implicit in current classifications. Misclassifications involving Veniliornis at both the generic and tribal levels appear to result from convergent evolution of plumage traits in specific forest types. We infer that the common ancestor of Veniliornis entered South America approximately at the time the Isthmus of Panama was formed, and diversification within South America was rapid.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 87 , 611–624.  相似文献   

4.
The leaf anatomy of Bomarea is described and related to ecological conditions. The principal architecture of all species is very similar; adaptations are developed in numerous differences, for instance degree of lignification. All species have inverse leaves, the adaxial side being the stomatous side. In most species, the leaves are resupinate, the lower surface being the adaxial. Theories for the cause of resupination are discussed.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 152 , 73–90.  相似文献   

5.
All amphibians are thought to possess two distinct types of dermal gland: mucous and granular. Mucous glands typically produce an acidic, flocculent and carbohydrate positive secretion that keeps skin moist and helps maintain homeostasis. In this study, we use a battery of histochemical tests to identify these traditional mucous glands in the dermis of the plethodontid salamander Ensatina eschscholtzii . The periodic acid-Schiff, alcian blue, toluidine blue and carmine reactions reveal the absence of both acidic glycosaminoglycans and traditional mucous glands. Instead, E. eschscholtzii produces neutral mucus in specialized granular glands, which we name mucus-producing granular glands (MPGGs). The loss of traditional mucous glands is a derived trait for Ensatina .  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 87 , 469–477.  相似文献   

6.
Previous phylogenetic analyses of Orchidaceae subtribe Orchidinae resulted in the proposal to classify Coeloglossum viride (L.) Hartman within the genus Dactylorhiza in order to maintain its monophyly. In this paper, we report some results that contradict previous studies regarding the monophyly of the traditional Dactylorhiza and its phylogenetic relationship with Coeloglossum. Our results, which combine sequences of the internal and external transcribed spacers of the nuclear ribosomal DNA, support the monophyly of Dactylorhiza , with Coeloglossum being a sister clade. The position of C. viride in the phylogenetic tree, and the considerable morphological differences with respect to Dactylorhiza , incline us to retain both lineages as distinct genera.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 152 , 261–269.  相似文献   

7.
Cerdia is a poorly understood genus of minute cushiony plants endemic to Mexico that is traditionally placed in subfamily Paronychioideae, tribe Polycarpeae (Caryophyllaceae). Morphological observations and phylogenetic analysis of ITS DNA sequences were carried out to determine the number of species, heretofore controversial, that constitute the genus as well as its position within Caryophyllaceae. Samples of Cerdia were collected through its entire range of distribution and together with previous specimens were used in morphological analyses. Nineteen terminal taxa were considered in a phylogenetic analysis with representatives of the different lineages in Caryophyllaceae. Results indicated that Cerdia is a monotypic genus, including only one variable species, C .  virescens , but its phylogenetic affinities remain doubtful.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 152 , 1–13.  相似文献   

8.
Kladothrips rugosus Froggatt has previously been considered a single polyphagous species that, in Australia, induces galls on several species of Acacia , with the gall structure varying both within and between hosts. On Acacia papyrocarpa , two types of gall are induced by this species, one with the surface ridged but the other with the surface smooth. Using sequence data from cytochrome oxidase subunit I (CO I ) and elongation factor-1 alpha gene fragments, we show that the thrips inducing these two gall-types are genetically distinct and comprise separate lineages. Uncorrected ' p ' distances calculated from CO I gene fragments were 0.000 and 0.006 within lineages and 0.074 and 0.078 between lineages. The between-lineage distances are comparable with distances between morphologically distinct species of other Acacia gall-thrips. Re-examination of adult thrips from the two gall types revealed consistent differences in body colour, as well as in body sculpture. Together with observations on gall founding behaviour, these data indicate that the thrips populations in the two gall types on A. papyrocarpa are reproductively isolated and should be considered as separate species. The form from smooth galls on A. papyrocarpa is therefore described as Kladothrips nicolsoni sp. nov. , although the form from ridged galls can be considered only as ' K. rugosus agg.'. These inconsistencies in the taxonomic status of the various units within the K. rugosus species complex are discussed, although most of them cannot be distinguished morphologically at present.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 88 , 555–563.  相似文献   

9.
A total of nine enzymes coded by 14 loci were assayed for each of six populations (from the north-eastern Atlantic and the Mediterranean) of two sea bream subspecies ( Diplodus sargus sargus and Diplodus sargus cadenati ). Diagnostic alleles were observed for each subspecies, although there were several common alleles. Estimates of variance in allele frequencies among samples ( F ST) revealed significant differences ( P  < 0.05) among both subspecies. Genetic divergence was found between Atlantic and Mediterranean samples: values for genetic distances were higher than 0.163. Furthermore, D. sargus cadenati populations displayed a higher mean weight and length than D. sargus sargus populations and significant differences in growth were found among subspecies and populations. These results are discussed in terms of levels of gene flow and its respective relationships with water circulation in the Strait of Gibraltar and geological events.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 89 , 705–717.  相似文献   

10.
Potential prey are often exposed to multiple predators that vary in their foraging tactics and ability to detect prey. For animals that rely on crypsis to avoid predators, one solution is to alter their behaviour or appearance to maximize crypsis in ways that are specific to different types of predator. We tested whether dwarf chameleons ( Bradypodion transvaalense ) showed different behavioural responses, including colour change, towards multiple predators (bird and snake models) that detect and capture prey in different ways, and whether these antipredator responses varied geographically. Chameleons consistently used the same body postures (lateral compression and flipping to the opposite side of the branch) and displayed similar chromatic (colour) contrast against the natural background in response to both predator types. However, they became significantly more achromatically contrasting (brighter) in the presence of the snake compared to the bird. This relative difference in achromatic contrast towards the two types of predator was consistent among populations. There were also significant differences in both absolute achromatic and chromatic contrast among populations despite very similar light environment, background coloration and habitat structure. Our results highlight facultative crypsis as one type of flexible antipredator tactic and emphasize the importance of visual ecology in understanding prey–predator interactions.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 88 , 437–446.  相似文献   

11.
12.
Salamander populations of the Plethodon jordani species complex form a challenging system for applying the general lineage concept of species to diagnose population-level lineages. The present study reports and analyses mitochondrial-DNA haplotypes (∼1200 nucleotide bases from the genes encoding ND2, tRNATrp, and tRNAAla from 438 salamanders) from 100 populations representing six species of the P. jordani complex ( Plethodon amplus , Plethodon cheoah , Plethodon jordani , Plethodon meridianus , Plethodon metcalfi , and Plethodon montanus ) with comparative analyses of previously published allozymic data to reconstruct the evolutionary history of this group and to diagnose species lineages. Analyses of mitochondrial haplotypic data include nested-cladistic analysis of phylogeography, analysis of molecular variance, hierarchical analysis of nucleotide-diversity measures, and likelihood-based estimates of recent temporal changes in population size. New analyses of allozymic data include multidimensional scaling and principal component analyses, and both data sets are analysed and compared for congruent genetic structure using Mantel correlation tests. These analyses in combination identify the six named species as distinct evolutionary lineages despite sporadic genetic exchanges among them and some discordance between mitochondrial DNA and allozymic markers. Sexual isolation is not complete for any pair of these six species, but they replace each other geographically and appear to block the geographical spreading of their neighbours. The P. jordani complex is a strong study system for investigating the genetic and ecological processes responsible for vicariant speciation.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 89 , 25–51.  相似文献   

13.
This study highlights the morphological differences between two groups of plants; those that are recorded as hosts of the thrips Heliothrips haemorrhoidalis (Bouché) and those that remain free from infestation. Scanning electron microscope techniques were used to describe the morphology of the leaf surface of 19 species in order to help identify which morphological features could play a role in the selection of plant species by thrips from among a diverse botanical collection. H. haemorrhoidalis had a preference for species with leaves that were coriaceous, with one or both surfaces being smooth. Plants evading these thrips commonly possessed glandular trichomes. Thus morphology may have a role in deterring thrips from the leaf surface, as well as influencing the behaviour of predators that control thrips. Further detailed studies into the chemistry of leaves of hosts and nonhost species may help to further our understanding of selection mechanisms.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 152 , 109–130.  相似文献   

14.
The present study investigated how variation in mating distribution in time and among males influences the operational sex ratio (OSR) with a simulation inspired by paternally caring fish. Varying (1) the potential reproductive rate of each sex, (2) the mating distribution among males, and (3) the length of male mating phase, we created different mating patterns. In each case, we searched for the adult sex ratio that resulted in an OSR of 50% (where sex-roles switch). This approach enabled a comparison with a previous model. We found that the OSR was influenced by the distribution of matings in time and among males when the male mating phase was limited by a parental phase. Furthermore, the mating dynamics were shaped by the fact that the numbers of males and females and their capacities for collateral investment affected OSR immediately from the start of the reproductive season, whereas their times-out had a delayed effect on OSR.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 89 , 551–559.  相似文献   

15.
Using genetic techniques (mtDNA, microsatellites and allozymes), this study investigated patterns of gene flow in two plotosid catfish species ( Neosilurus hyrtlii and Porochilus argenteus ), at various hierarchical scales in the dryland rivers of western Queensland, Australia. The study area constituted two major catchments, Cooper and Darling, representing arid and semiarid systems, respectively. Results generally conformed to expectations, with high levels of gene flow observed within catchments and limited contemporary gene flow evident across catchment boundaries. However, the isolation between catchments was more recent than expected, occurring approximately 40 000–72 000 years ago. Also contrary to predictions, genetic structure within the Cooper catchment did not fit the stream hierarchy model of genetic differentiation, which there was evidence of in the Darling catchment. This was hypothesized to relate to the different climatic regimes and hydrological inputs in each system, leading to a more genetically homogeneous system in the Cooper than in the Darling system.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 87 , 457–467.  相似文献   

16.
Additional occurrences of cetrarioid lichens in India are documented. Tuckneraria sikkimensis Divakar & Upreti sp. nov. is described as a new species. Tuckneraria ahtii Randlane & Saag, T. togashii (Asahina) Randlane & A. Thell and Cetrelia sinensis W.L. Culb. & C.F. Culb. are reported as new records.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 150 , 249–251.  相似文献   

17.
18.
Missing data are frequent in morphometric studies of both fossil and recent material. A common method of addressing the problem of missing data is to omit combinations of characters and specimens from subsequent analyses; however, omitting different subsets of characters and specimens can affect both the statistical robustness of the analyses and the resulting biological interpretations. We describe a method of examining all possible subsets of complete data and of scoring each subset by the 'condition' (ratio of first eigenvalue to second, or of second to first, depending on context) of the corresponding covariance or correlation matrix, and subsequently choosing the submatrix that either optimizes one of these criteria or matches the estimated condition of the original data matrix. We then describe an extension of this method that can be used to choose the 'best' characters and specimens for which some specified proportion of missing data can be estimated using standard imputation techniques such as the expectation-maximization algorithm or multiple imputation. The methods are illustrated with published and unpublished data sets on fossil and extant vertebrates. Although these problems and methods are discussed in the context of conventional morphometric data, they are applicable to many other kinds of data matrices.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 88 , 309–328.  相似文献   

19.
Body size, host choice and sex allocation in a spider-hunting pompilid wasp   总被引:1,自引:0,他引:1  
Two important relationships in parasitoid evolutionary ecology are those between adult size and fitness and between host quality and sex ratio. Sexually differential size–fitness relationships underlie predicted sex-ratio relationships. Despite each relationship receiving considerable attention, they have seldom been studied simultaneously or using field data. Here we report the biology of Anoplius viaticus paganu s Dahlbom, a little known parasitoid of spiders, using field and laboratory data. We found that larger foraging females were able to select larger host spiders from the field, thus identifying a relatively novel component of the size–fitness relationship. Larger offspring developed from larger hosts and, in agreement with the prediction of the host quality model of sex allocation, were generally female. Data on the size–fitness relationship for males are lacking and, in common with many prior studies, we could not evaluate sexually differential size–fitness relationships as an explanation for the observed sex-ratio patterns. Nonetheless, A. v. paganu s exhibited one of the strongest relationships between host size and offspring sex ratio yet reported.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 87 , 285–296.  相似文献   

20.
Chromosome counts are reported of 38 populations representing 24 species of the genus Cousinia from Iran, one of the main centres of speciation of the genus. Sixteen of the counts are new to science. Our results confirm that Cousinia exhibits a complex dysploid series ranging from x  = 13 to x  = 9. One of the basic chromosome numbers, x  = 9, is new for the genus and must be confirmed. Some considerations on the correlation between chromosome numbers and section classification are made.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 411–419.  相似文献   

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