Phenetic studies in Nuphar Sm. (Nymphaeaceae):variation in sect. Nuphar

Previous taxonomic assessments of the hydrophytic genus Nuphar Sm. (Nymphaeaceae) have inadequately considered the range of morphological variation existing in the genus. A comprehensive statistical analysis of morphological features among the recognized taxa of Nuphar is presented here, first using 10 fruit characters to delimit the separation of two infrageneric groups of taxa, and secondly using 31 characters to quantify the morphological variation found within sect. Nuphar. Results from combined phenetic analyses provided empirical support for recognition of two infrageneric groups of species in the genus (largely by fruit, stigmatic disk margin, neck, and stigmatic disk size) and for separation of taxa within sect. Nuphar (by leaf size, and fruit disk and neck size). Statistical analyses demonstrate that extensive variation in ranges of character states exists among sect. Nuphar taxa. However, a suite of qualitative and quantitative characters can be used to recognize five species and three subspecies within this predominantly Old World assemblage.     

Significance of variation and evaluation of potential characters in three morphologically similar species of <Emphasis Type="Italic">Barleria</Emphasis> sect. <Emphasis Type="Italic">Barleria</Emphasis> (Acanthaceae) in southern Africa

The variation exhibited within three species of Barleria (B. bechuanensis, B. irritans and B. jubata) was studied to establish whether it was discrete or continuous. Morphological characters were examined and recorded in matrices. Cluster analysis was employed to impose a hierarchical non-overlapping association among operational taxonomic units (OTUs) while ordination was used to establish whether the variation was discrete or continuous. Discrete characters were determined from quantitative morphological data using box and whisker plots. Locality information for the OTUs was obtained from herbarium labels and used to generate maps to illustrate geographic distribution of taxa. Cluster analysis and ordination demonstrated that there was discrete variation within Barleria bechuanensis, B. irritans and B. jubata, which each split into two distinct clusters, although box and whisker plots illustrated that many quantitative characters overlapped within and between species. Since clear morphological gaps between clusters are assumed to be indicators of breaks in gene flow, the distinct clusters were recognised at species level.     

Species delimitation: inferring gaps in morphology across geography

Species are commonly delimited on the basis of gaps in patterns of morphological variation, but there seems to be little recent work on methods to objectively assess such gaps. Here, we introduce a statistical approach that uses measurements of continuous morphological characters and geographic variation in those characters to (i) measure the strength of the evidence for the existence of a gap in morphological variation between two hypothesized species and (ii) examine if a gap in morphological variation between two hypothesized species can be explained by an alternative hypothesis of geographic variation within a species. This approach is based on recent developments in analyses of multivariate normal mixtures, estimates of multivariate tolerance regions, and principal coordinates of neighboring matrices. We demonstrate the application of the approach by examining previously proposed hypotheses of species limits in the plant genus Escallonia. We discuss the main features of the method, including potential limitations, in relation to other approaches that use gaps in morphological variation as a criterion for species delimitation. The method we propose can help strengthen the link between the theory and practice of species delimitation by increasing the transparency and consistency of taxonomic decisions based on morphology, thus contributing to integrative approaches for species delimitation that consider morphological and geographic data on an equal footing with other kinds of information.     

The species concept as an emergent property of population biology

Resurgent interest in the genetics of population divergence and speciation coincides with recent critical evaluation of species concepts and proposals for species delimitation. An important result of these parallel trends is a slight but important conceptual shift in focus away from species diagnoses based on prior species concepts or definitions, and toward analyses of the processes acting on lineages of metapopulations that eventually lead to differences recognizable as species taxa. An advantage of this approach is that it identifies quantitative metapopulation differences in continuous variables, rather than discrete entities that do or do not conform to a prior species concept, and species taxa are recognized as an emergent property of population-level processes. The tension between species concepts and diagnosis versus emergent recognition of species taxa is at least as old as Darwin, and is unlikely to be resolved soon in favor of either view, because the products of both approaches (discrete utilitarian taxon names for species, process-based understanding of the origins of differentiated metapopulations) continue to have important applications.     

Species boundaries within the<Emphasis Type="Italic"> Acropora humilis</Emphasis> species group (Cnidaria; Scleractinia): a morphological and molecular interpretation of evolution

Species boundaries remain unresolved in many scleractinian corals. In this study, we examine evolutionary boundaries of species in the Acropora humilis species group. Five morphologically discrete units are recognized using principal components and hierarchical cluster analyses of quantitative and qualitative characters, respectively. Maximum parsimony and likelihood analyses of partial 28S rDNA sequences suggest that these morphological units diverged to form two evolutionarily distinct lineages, with A. humilis and A. gemmifera in one lineage and A. digitifera and two morphological types of A. monticulosa in the other. Low levels of sequence divergence but distinct morphologies of A. humilis and A. gemmifera within the former lineage suggest recent divergence or ongoing hybridization between these species. Substantially higher levels of divergence within and between A. digitifera and A. monticulosa suggest a more ancient divergence between these species, with sequence types being shared through occasional introgression without disrupting morphological boundaries. These results suggest that morphology has evolved more rapidly than the 28S rDNA marker, and demonstrate the utility of using morphological and molecular characters as complementary tools for interpreting species boundaries in corals.     

Patterns of morphometric variation and a new supraspecific classification of apomictic taxa of Hieracium (Asteraceae) from Denmark and southern Sweden

Patterns of variation among all micro-species of Hieracium sect. Hieracium and H. sect. Vulgata known from Denmark and southern Sweden are investigated. Forty-three, possibly independent morphological characters are used. Significant correlations were revealed among the majority of the characters. Multivariate analyses did not reveal any discontinuities in the variation or any discrete groups of species. However, there were obvious correlations between previous taxonomic classifications and the result of the multivariate analyses. Based on the statistical analyses, three sections and 38 informal species aggregates are recognized. H. sect. Bifidum T. Tyler is described anew. The characters that turned out to be most influential in the multivariate analyses, and thus most important for the classification, were the distribution of stellate tomentum on the phyllaries, the amount of glandular hairs and the amount and pigmentation of simple hairs on the phyllaries, the shape of the leaf-base and the regularity of the leaf dentation. The evolution of the group and the taxonomic treatment is thoroughly discussed in the light of the results.     

Phylogeny and taxonomy of the round-eared sengis or elephant-shrews, genus Macroscelides (Mammalia, Afrotheria, Macroscelidea)

The round-eared sengis or elephant-shrews (genus Macroscelides) exhibit striking pelage variation throughout their ranges. Over ten taxonomic names have been proposed to describe this variation, but currently only two taxa are recognized (M. proboscideus proboscideus and M. p. flavicaudatus). Here, we review the taxonomic history of Macroscelides, and we use data on the geographic distribution, morphology, and mitochondrial DNA sequence to evaluate the current taxonomy. Our data support only two taxa that correspond to the currently recognized subspecies M. p. proboscideus and M. p. flavicaudatus. Mitochondrial haplotypes of these two taxa are reciprocally monophyletic with over 13% uncorrected sequence divergence between them. PCA analysis of 14 morphological characters (mostly cranial) grouped the two taxa into non-overlapping clusters, and body mass alone is a relatively reliable distinguishing character throughout much of Macroscelides range. Although fieldworkers were unable to find sympatric populations, the two taxa were found within 50 km of each other, and genetic analysis showed no evidence of gene flow. Based upon corroborating genetic data, morphological data, near sympatry with no evidence of gene flow, and differences in habitat use, we elevate these two forms to full species.     

A morphological and chemical analysis of geographical variation in Tilia L. of eastern North America

A statistical analysis of morphological variation and a Chromatographic analysis of flavonoid variation were performed to determine taxonomic relationships among the species ofTilia of eastern North America. No apparent morphological discontinuities were seen between populations within the sample area although two characters (involving leaf pubescence and gland length) showed definite patterns of geographical variation. Flavonoid patterns showed definite differences between northern and southern populations with an intermediate zone in the Smoky Mountain region. The continuous nature of the morphological and flavonoid variation suggested that the genus as represented in eastern North America should be regarded as one species,Tilia americana L.     

Morphological and molecular variation in tiger beetles of the Cicindela hybrida complex: is an ‘integrative taxonomy’ possible?

Current taxon assignments at the species level are frequently discordant with DNA-based analyses. Recent studies on tiger beetles in the Cicindela hybrida complex identified discordance between mtDNA patterns and the entities currently defined by the taxonomic literature. To test the accuracy of morphologically delimited groups, five named taxa (species) from 24 representative sampling sites across Europe were scored for 41 external morphological characters. Three of the named taxa were 'diagnosable', that is, defined by between one and three characters unique to each group. Newly sequenced ITS1 and existing mitochondrial cox1 markers established 20 and 22 different haplotypes, respectively, but only cox1 produced (four) diagnosable units. Phylogenetic analysis and statistical parsimony networks showed poor congruence of character variation with the taxonomic entities (and each other). Variation in morphological characters was therefore tested directly for association with DNA-based nesting groups at various hierarchical levels using permutational contingency analysis. Significant statistical associations of 11 (of 13 variable) morphological characters were observed with nesting groups from ITS1 and mitochondrial DNA markers, predominantly at the 4-step level. The analysis demonstrates the need for formal tests of congruence with morphological variation at the level of individual characters, a step that is omitted from recent studies of 'integrative taxonomy'. In addition, statistical correlation of particular morphological characters with DNA-based nesting groups can identify the lowest hierarchical level at which various character sets show congruence, as a means to define evolutionarily separated entities supported by diverse data sources.     

Systematics of Andean gladiator frogs of the Hypsiboas pulchellus species group (Anura,Hylidae)

Köhler, J., Koscinski, D., Padial, J. M., Chaparro, J. C., Handford, P., Lougheed, S. C. & De la Riva, I. (2010). Systematics of Andean gladiator frogs of the Hypsiboas pulchellus species group (Anura, Hylidae). —Zoologica Scripta, 39, 572–590. We revisit the taxonomic status of Andean species and populations of frogs of the Hypsiboas pulchellus group using multiple lines of evidence potentially indicative of evolutionary lineage divergence in anurans: differences in qualitative morphological or bioacoustic character states, no overlap in quantitative characters of advertisement calls, and monophyly of gene genealogies. We found qualitative and quantitative morphological characters to be extremely variable among species and populations of the group and thus of very limited use in assessing lineage divergence. In contrast, phylogenetic analyses based on 16S rRNA and cytochrome b sequences resolved highly supported clades that are in concordance with bioacoustic differences. The results support the specific distinctness of most nominal species recognized in the group, including the Bolivian Hypsiboas balzani and Hypsiboas callipleura, two species that were considered to be synonymous, and revealed the presence of an undescribed species from southern Peru, which is here described as Hypsiboas gladiator sp. n. In contrast, Hypsiboas andinus and Hypsiboas riojanus were mutually paraphyletic, and showed no differences in morphology and acoustic characters. Consequently, we regard the former as a junior synonym of the latter. However, we discovered that populations of H. riojanus from central Bolivia exhibit some degree of genetic differentiation and advertisement call differences with respect to Argentine populations, but sampling of these Bolivian populations is too sparse to draw taxonomic conclusions. Our phylogenetic results support the hypothesis that ancestral lineages of the Andean H. pulchellus group experienced successive splitting events along a latitudinal gradient from north to south.     

泡沙参复合体(桔梗科)的物种生物学研究——Ⅲ.性状的遗传变异及其分类价值

阐明性状变异的遗传基础是评估性状分类价值以及揭示类群关系和进化过程的前提。本文根据泡沙参复合体内6个天然居群的材料,利用居群样本分析、子代测定和杂交试验等手段,结合统计学方法对该复合体一些在以往类群划分中起鉴别作用的形态性状进行了遗传学分析。结果表明,叶形、叶缘锯齿数目和大小、茎叶被毛、花萼裂片齿数、花梗长短等性状都是遗传性比较强的性状,而且性状之间有很强的相关性。但是,这些性状在居群内呈现连续变异且变异幅度非常大,以致于变异的两个极端个体被分别作为不同的种处理。通过对野外居群样本的统计分析和对极端变异类型个体所进行的子代测定及其人工杂交,进一步证实上述性状是受多基因决定的数量性状,其变异幅度大,变异式样中并不存在任何程度的间断性,因而至少在本复合体内没有鉴别意义。因此,以往建立在上述性状变异基础上的3个类群(A.biformifolia Y.Z.Zhao;A.bockiana Diels和A.polydentata P.F.Tu et G.I.Xu)均不成立。最后,本文对形态性状变异的遗传基础及其与类群划分的关系进行了讨论。     

Biosystematic Studies on Adenophora potaninii Korsh. Complex (Campanulaceae) III. Genetic Variation and Taxonomic Value of Morphological Characters

Adenophora potaninii Korsh．complex is a morphologically variable group including six species．As shown in many species in the genus Adenophora,the variability of many morphological characters in the complex under investigation is amazingly great,which brings difficulties in the delimitation and indentification of taxa．In the present study,six populations representing five species in the complex were systematically sampled to investigate the pattern of morphological variation within population and to detect the genetic basis of the variation with progeny tests and controlled crosses．The results are as follows： Great morphological variation within population is found (Fig.1),including characters such as leaf shape,teeth number and size of leaf margins,teeth number of calyx lobes,and indumentum on the surface of stems and leaves,which were previously considered as diagnotic．Systematic sampling and statistical analysis show that the differences in the above characters exhibit continuous patterns of variation within population (Fig．1,2),though they are highly correlated (Table 2)．From progeny testing and crossing between two contrast types of individuals (oblong,dentate and pubescent leaves vs．narrow,entire and glabrous leaves)it is evident that those characters show continuous variability in segregating progenies (Fig.3,4)and appear to be influenced by large numbers of loci with individually slight effects．Since most wild populations were highly heterozygous for those characters,the individuals in one extreme of variation can produce their variable offsprings including individuals similar to those in the other extreme (Fig. 3). This is also true for the indumentum density on stems and teeth number of calyx lobes. In this complex, A. biformifolia Y. Z. Zhao, A. bockiana Diels and A. polydentata P.F. Tu et G. J. Xu were described exclusively based on leaf shapes, teeth number of leaf margins and calyx lobes, teeth size of leaf margins, and indumentum on the surface of stemsand leaves. It is demonstrated, however, that the variation of those characters is of a quantitative nature and show no discontinuities. As a result, genetic analysis of diagnostic characters along with their sympatric distribution and same habitats, strongly suggest that A.biformifolia as well as A. bockiana and A. polydentata are actually the extreme individuals within A. wawreana and A. potaninii respectively and should not be recognized as taxa at any taxonomic level.     

REVISED CLASSIFICATION OF THE GENUS PACHYMENIA BASED ON MORPHOLOGICAL AND MOLECULAR CHARACTERS

Taxonomic discrimination in the genus Pachymenia (Rhodophyta) in New Zealand is based primarily on phenotypic characters of the thallus. The taxonomic problems raised by this classification method are due to highly variable thallus characters such as blade thickness, blade width, degree of thallus branching, and variation in anatomical characters. Delineation of species is further complicated by a lack of adequate knowledge about the responses of phenotype to environmental variation. There are currently three species recognized in this genus that are endemic to New Zealand: a prostrate species P. crassa , and two erect species, P. laciniata and P. lusoria. In this study, two approaches are used to investigate the current delineation of these species. Morphological and anatomical characters of field collected material and herbarium specimens from throughout the species' distributional ranges were quantified. Multivariate analyses were used to identify discrete phenotypic groups. Species relationships were further analyzed by quantifying the variation found within the internal transcribed spacer region (ITS) of the nuclear ribosomal DNA. The results obtained from both approaches will be discussed with regards to possible re-classification of species relationships within this genus. We suggest that the two erect species should be merged, and the currently recognized P. lusoria should be separated into at least two taxonomic groups.     

白腰雪雀分类地位的商榷

自腰雪雀Onychostruthus taczanowskii(Przewalski)的分类地位比较混乱.在早期的分类系统中,它被归属于雪雀属Montifringilla下.后期由于生态习性与行为特征的不同,被划分至地雀属Pyrgilauda下;又有将它划分为独立属--高原雀属Onychostruthus的观点.本文结合身体量衡度数值特征、外部形态特征以及遗传差异上的研究,综合探讨白腰雪雀的分类地位.对量衡度特征的因子分析发现:白腰雪雀与地雀属种类在体长、体重、翅长、尾长、嘴长与跗蹠长上明显不同,其体形明显偏大.形态特征的聚类分析显示:白腰雪雀与地雀属种类的平均特征差异为0.3902～0.5122,而这些种类间平均特征差异为0.1281～0.2195.比较属间差异发现:石雀Petronia petronia与地雀属种类为0.4878～0.5385,树麻雀Passer montanus与地雀属种类为0.4872～0.5610.麻雀属与石雀属为0.3415,这些结果显示自腰雪雀与地雀属种类的差异已经达到石雀属、麻雀属与地雀属属间的差异.通过比较白腰雪雀与石雀的遗传差异(0.2578),地雀属种类与石雀的遗传差异(0.2386～0.3193),发现白腰雪雀与地雀属种类具有较大的遗传差异(0.2267～0.3143),几近于地雀属与石雀属间的差异.综合量衡度、形态以及遗传等特征的分析结果,作者认为白腰雪雀与地雀属种类有较大的差异,两者间的差异已经达到了它们与近缘属石雀属和麻雀属间的差异,以及近缘属之间的差异,因此,建议白腰雪雀应作为一个独立的属,高原雀属Onychostruthus.     

Intraspecific flavonoid variation

This review is concerned with variation of flavonoid patterns within species. Many examples of species with invariant flavonoid patterns are known; there are at least as many examples where complex arrays of pigments are known. Eight categories of variation are discussed: 1) qualitatively invariant pigment profiles, 2) quantitative variation, 3) flavonoid races that do not correspond to recognized taxonomic groups, 4) flavonoid races that do correspond to recognized taxonomic groups, 5) flavonoid profile differences between different ploidy levels, 6) differences between organs or between tissues, 7) differences between developmental stages, and 8) environmentally influenced flavonoid profiles. These types of variation seem to occur randomly in the plant kingdom. Members of the same family, or in some cases, the same genus, can display different types of variation. Careful attention to these sources of variation is necessary before flavonoid characters can be used in taxonomic studies.     

Morphometric studies and taxonomic delimitation in Menonvillea scapigera and related species (Cremolobeae: Brassicaceae)

Previous systematic treatments of Menonvillea recognized a group of six morphologically related species, the ‘M. scapigera group,' distinguished by having pinnately lobed leaves and united filaments of median staminal pairs. The number of recognized species ranged from six to two, one with three subspecies. In order to clarify the taxonomy of this group, multivariate and univariate analyses of qualitative and quantitative characters from herbarium specimens were performed. Additionally, to test the morphological results, the phylogenetic relationships and degree of exclusive ancestry were studied using ITS sequences and the genealogical sorting index. Our results support the recognition of three species (M. famatinensis, M. hirsuta, M. scapigera) delimited by a unique combination of qualitative characters. Quantitative characters support the division of the latter species into two subspecies: scapigera and longipes. The molecular data are congruent with the morphology and support the inclusion of M. hookeri within M. scapigera. A key to taxa of the M. scapigera group is presented.     

Evaluation of the fossil fish‐specific diversity in a chadian continental assemblage: Exploration of morphological continuous variation in Synodontis (Ostariophysi,Siluriformes)

In the fossil record, the quantification of continuous morphological variation has become a central issue when dealing with species identification and speciation. In this context, fossil taxa with living representatives hold great promise, because of the potential to characterise patterns of intraspecific morphological variation in extant species prior to any interpretation in the fossil record. The vast majority of catfish families fulfil this prerequisite, as most of them are represented by extant genera. However, although they constitute a major fish group in terms of distribution, and ecological and taxonomic diversity, the quantitative study of their past morphological variation has been neglected, as fossil specimens are generally identified based on the scarcest remains, that is, complete neurocrania that bear discrete characters. Consequently, a part of freshwater catfish history is unprospected and unknown. In this study, we explored the morphological continuous variation of the humeral plate shape in Synodontis catfishes using Elliptic Fourier Analysis (EFA), and compared extant members and fossil counterparts. We analysed 153 extant specimens of 11 Synodontis species present in the Chad basin, in addition to 23 fossil specimens from the Chadian fossiliferous area of Toros Menalla which is dated around 7 Ma. This highly speciose genus, which is one of the most diversified in Africa, exhibits a rich fossil record with several hundred remains mostly identified as Synodontis sp. The analysis of the outline of the humeral plate reveals that some living morphological types were already represented in the Chad Basin 7 My ago, and allows for the discovery of extinct species. Beside illuminating the complex Neogene evolutionary history of Synodontis, these results underline the interest in the ability of isolated remains to reconstruct a past dynamic history and to validate the relevance of EFA as a tool to explore specific diversity through time. J. Morphol. 277:1486–1496, 2016. © 2016 Wiley Periodicals, Inc.