Parsimonious Trees Research Articles

Computing the blocks of a quasi-median graph

Quasi-median graphs are a tool commonly used by evolutionary biologists to visualise the evolution of molecular sequences. As with any graph, a quasi-median graph can contain cut vertices, that is, vertices whose removal disconnect the graph. These vertices induce a decomposition of the graph into blocks, that is, maximal subgraphs which do not contain any cut vertices. Here we show that the special structure of quasi-median graphs can be used to compute their blocks without having to compute the whole graph. In particular we present an algorithm that, for a collection of n aligned sequences of length m, can compute the blocks of the associated quasi-median graph together with the information required to correctly connect these blocks together in run time O(n2m2), independent of the size of the sequence alphabet. Our primary motivation for presenting this algorithm is the fact that the quasi-median graph associated to a sequence alignment must contain all most parsimonious trees for the alignment, and therefore precomputing the blocks of the graph has the potential to help speed up any method for computing such trees.

Molecular characterization and genetic diversity of the starch branching enzyme (SBE) gene from Amaranthus: the evolutionary origin of grain amaranths

Full-length genomic DNA clones encoding starch branching enzymes (SBEs) from three cultivated grain amaranths were isolated and characterized. A sequence analysis showed that the SBE genes from Amaranthus caudatus, A. cruentus, and A. hypochondriacus, viz. SBE-ca, SBE-cr, and SBE-hy, respectively, contained the same exon and intron structure and consisted of 961 amino acids with molecular weights of approximately 108.4 kDa. The lengths of the genes were 7,446 (SBE-ca), 7,453 (SBE-cr), and 7,443 bp (SBE-hy), and they are highly homologous. We also tested, for the first time, the potential use of SBE from diverse genetic sources to answer long-standing questions on the origin of grain amaranths. The maximum parsimony tree based on the SBE sequence data suggests that A. hybridus is the progenitor wild species of grain amaranths. The results could be summarized as follows: (1) the A. hybridus species comprise all grain amaranths, which can then be divided into two subgroups; (2) A. caudatus and A. hypochondriacus and/or A. caudatus and A. quitensis appear to be closely related to each other; (3) A. powellii was the most distantly related to the other five species in the A. hybridus complex. These results indicate that A. hybridus is the ancestor species in at least two separate domestication events, lending support to the theory of three separate, rather than one, domestication events involving A. hybridus as the common ancestor. A new approach to investigating the genetic diversity in Amaranthus using the nuclear gene SBE provided useful information on the evolutionary origin of three cultivated species.

Algorithms to model single gene, single chromosome, and whole genome copy number changes jointly in tumor phylogenetics.

We present methods to construct phylogenetic models of tumor progression at the cellular level that include copy number changes at the scale of single genes, entire chromosomes, and the whole genome. The methods are designed for data collected by fluorescence in situ hybridization (FISH), an experimental technique especially well suited to characterizing intratumor heterogeneity using counts of probes to genetic regions frequently gained or lost in tumor development. Here, we develop new provably optimal methods for computing an edit distance between the copy number states of two cells given evolution by copy number changes of single probes, all probes on a chromosome, or all probes in the genome. We then apply this theory to develop a practical heuristic algorithm, implemented in publicly available software, for inferring tumor phylogenies on data from potentially hundreds of single cells by this evolutionary model. We demonstrate and validate the methods on simulated data and published FISH data from cervical cancers and breast cancers. Our computational experiments show that the new model and algorithm lead to more parsimonious trees than prior methods for single-tumor phylogenetics and to improved performance on various classification tasks, such as distinguishing primary tumors from metastases obtained from the same patient population.

The most parsimonious tree for random data

Applying a method to reconstruct a phylogenetic tree from random data provides a way to detect whether that method has an inherent bias towards certain tree ‘shapes’. For maximum parsimony, applied to a sequence of random 2-state data, each possible binary phylogenetic tree has exactly the same distribution for its parsimony score. Despite this pleasing and slightly surprising symmetry, some binary phylogenetic trees are more likely than others to be a most parsimonious (MP) tree for a sequence of k such characters, as we show. For k=2, and unrooted binary trees on six taxa, any tree with a caterpillar shape has a higher chance of being an MP tree than any tree with a symmetric shape. On the other hand, if we take any two binary trees, on any number of taxa, we prove that this bias between the two trees vanishes as the number of characters k grows. However, again there is a twist: MP trees on six taxa for k=2 random binary characters are more likely to have certain shapes than a uniform distribution on binary phylogenetic trees predicts. Moreover, this shape bias appears, from simulations, to be more pronounced for larger values of k.

Molecular phylogenetic status of Siberian roe deer (Capreolus pygargus) based on mitochondrial cytochrome b from Jeju Island in Korea

In order to elucidate the genetic diversity and taxonomic status of Siberian roe deer (Capreolus pygargus) from the Korean peninsula, partial sequences of the mitochondrial cytochrome b gene were analyzed. We collected 57 roe deer samples from Mainland and Jeju Island between July 2004 and June 2009. A total of 50 sequences (1,070 bp) were obtained, and seven haplotypes were defined. Five haplotypes were found from Mainland, and two were discovered from Jeju Island. The genetic diversity was lower in the Jeju Island population than in the Mainland population. In addition, both the consensus neighbor-joining tree and maximum parsimony tree showed an identical topology between the Mainland and Jeju Island clades. Based on the results, two subspecies of the Korean roe deer were confirmed. Siberian roe deer in Jeju Island showed a distinct difference in the cytochrome b gene compared with other Siberian roe deer, being a unique native species inhabiting only Jeju Island in Korea. Because Siberian roe deer in Jeju Island can be classified at subspecies level, the new subspecies in Jeju was named Capreolus pygargus jejuensis in this study. For this new subspecies, reasonable conservation and management effort is needed in the future.

Phylogeny, speciation, and distribution of the Japanese dwarf bamboos of genus Sasa and allies

AbstractDevelopment of the concept of the subfamily Bambusoideae during the past three decades is briefly reviewed. Phylogeny, putative hybrid taxa, a new, simplified key to explicit identification, and the revision of the distribution range among the Japanese dwarf bamboos of genus Sasa and its close allies are discussed. Based on analyses of the random amplified polymorphic DNA and morphological data and of FLOWERING LOCUS T (FT) homologs, parsimonious trees resolved that genus Sasa sec. Macrochlamys were the most basal and sect. Monilicladae were the next most basal, followed by the terminal sister clades of sects. Sasa and Crassinodi.

Genetics and shell morphometrics of assimineids (Mollusca, Caenogastropoda, Truncatelloidea) in the St Lucia Estuary, South Africa.

The Assimineidae are a family of amphibious microgastropods that can be mostly found in estuaries and mangroves in South Africa. These snails often occur in great numbers and are ecologically important to the St Lucia Estuary, which forms a crucial part of the iSimangaliso Wetland Park, a UNESCO World Heritage Site. Genetic and shell morphometric analyses were conducted on individuals collected from nine localities distributed from the northern lake regions to the southern lake and the mouth of the St Lucia estuarine lake. Mitochondrial (COI) and nuclear (28S) DNA was used to construct Bayesian Inference, Neighbour-joining, Maximum Parsimony and Maximum Likelihood trees. Principal Component Analysis and Cluster Analysis were performed on standard shell parameter data. Results indicate that two different taxa are present in St Lucia. The taxon comprising individuals from the South Lake and St Lucia Estuary Mouth is identified as Assiminea cf. capensis Bartsch, in accordance with the latest taxonomic consensus. The taxon comprising assimineid individuals from False Bay, North Lake and South Lake, is here tentatively named “Assiminea” aff. capensis (Sowerby). These two taxa exhibit patterns of spatial overlap that appear to vary depending on environmental parameters, particularly salinity. The need to resolve the complex taxonomy of assimineids is highlighted.

Hide and vanish: Data sets where the most parsimonious tree is known but hard to find, and their implications for tree search methods

Three different types of data sets, for which the uniquely most parsimonious tree can be known exactly but is hard to find with heuristic tree search methods, are studied. Tree searches are complicated more by the shape of the tree landscape (i.e. the distribution of homoplasy on different trees) than by the sheer abundance of homoplasy or character conflict. Data sets of Type 1 are those constructed by Radel et al. (2013). Data sets of Type 2 present a very rugged landscape, with narrow peaks and valleys, but relatively low amounts of homoplasy. For such a tree landscape, subjecting the trees to TBR and saving suboptimal trees produces much better results when the sequence of clipping for the tree branches is randomized instead of fixed. An unexpected finding for data sets of Types 1 and 2 is that starting a search from a random tree instead of a random addition sequence Wagner tree may increase the probability that the search finds the most parsimonious tree; a small artificial example where these probabilities can be calculated exactly is presented. Data sets of Type 3, the most difficult data sets studied here, comprise only congruent characters, and a single island with only one most parsimonious tree. Even if there is a single island, missing entries create a very flat landscape which is difficult to traverse with tree search algorithms because the number of equally parsimonious trees that need to be saved and swapped to effectively move around the plateaus is too large. Minor modifications of the parameters of tree drifting, ratchet, and sectorial searches allow travelling around these plateaus much more efficiently than saving and swapping large numbers of equally parsimonious trees with TBR. For these data sets, two new related criteria for selecting taxon addition sequences in Wagner trees (the “selected” and “informative” addition sequences) produce much better results than the standard random or closest addition sequences. These new methods for Wagner trees and for moving around plateaus can be useful when analyzing phylogenomic data sets formed by concatenation of genes with uneven taxon representation (“sparse” supermatrices), which are likely to present a tree landscape with extensive plateaus.

A preliminary phylogenetic analysis of the New World Helopini (Coleoptera, Tenebrionidae, Tenebrioninae) indicates the need for profound rearrangements of the classification.

Helopini is a diverse tribe in the subfamily Tenebrioninae with a worldwide distribution. The New World helopine species have not been reviewed recently and several doubts emerge regarding their generic assignment as well as the naturalness of the tribe and subordinate taxa. To assess these questions, a preliminary cladistic analysis was conducted with emphasis on sampling the genera distributed in the New World, but including representatives from other regions. The parsimony analysis includes 30 ingroup species from America, Europe and Asia of the subtribes Helopina and Cylindrinotina, plus three outgroups, and 67 morphological characters. Construction of the matrix resulted in the discovery of morphological character states not previously reported for the tribe, particularly from the genitalia of New World species. A consensus of the 12 most parsimonious trees supports the monophyly of the tribe based on a unique combination of characters, including one synapomorphy. None of the subtribes or the genera of the New World represented by more than one species (Helops Fabricius, Nautes Pascoe and Tarpela Bates) were recovered as monophyletic. Helopina was recovered as paraphyletic in relation to Cylindrinotina. One Nearctic species of Helops and one Palearctic species of Tarpela (subtribe Helopina) were more closely related to species of Cylindrinotina. A relatively derived clade, mainly composed by Neotropical species, was found; it includes seven species of Tarpela, seven species of Nautes, and three species of Helops, two Nearctic and one Neotropical. Our results reveal the need to deeply re-evaluate the current classification of the tribe and subordinated taxa, but a broader taxon sampling and further character exploration is needed in order to fully recognize monophyletic groups at different taxonomic levels (from subtribes to genera).

Scanning electron microscopy of male terminalia and its application to species recognition and phylogenetic reconstruction in the Drosophila saltans group.

The Drosophila saltans group consists of five subgroups and 21 species, most of which have been identified only by morphological aspects of the male terminalia revealed by drawings using a camera lucida and a bright-field microscope. However, several species in the group, mainly those included in the saltans subgroup, are difficult to differentiate using only these characteristics. In this study, we used scanning electron microscopy (SEM) to analyze 19 structures of the male terminalia in 10 species from the five saltans subgroups. Among these structures, nine could be identified only through SEM analysis. We aimed to find other characteristics useful for morphological recognition of these species and to use these characteristics for phylogenetic reconstruction. These morphological differences enabled us to effectively distinguish among sibling species. These findings confirmed the monophyly of this group as previously determined in evolutionary studies based on other markers. The single most parsimonious tree (CI = 87 and RI = 90) indicated that the cordata subgroup is the most basal lineage and the saltans subgroup is the most apical lineage, as shown in earlier studies based on morphological data. However, our findings differed somewhat from these studies with respect to the phylogenetic relationships of species in the saltans group indicating that this group is still a puzzle that remains to be deciphered.

The identity and genetic characterization of Simulium reptans (Diptera: Simuliidae) from central and northern Europe.

Although Simulium reptans Linnaeus is one of the first two blackfly species ever described its identity and taxonomy are still not precisely defined. S. reptans and closely related species from central and northern Europe were characterized based on genetic variability, haplotype number and haplotype distribution. S. galeratum can be considered a synonym of S. reptans, but despite this, two distinct species are present in Great Britain and central Europe. The available name S. reptantoides Carlsson can be used for the second species; earlier reported as S. reptans from Great Britain and central Europe. A total of 80 mitochondrial cytochrome c oxidase I gene sequences were analyzed: 44 S. reptans, 36 S. reptantoides; 38 from Great Britain, 19 from Slovakia, 8 from Lithuania, 3 from Latvia and 12 from Sweden. In 73 individuals a 606 bp section (long sequences), and in all 80 individuals a fully overlapping 453 bp section (short sequences) were analyzed. Results confirmed that S. reptans and S. reptantoides are two genetically isolated species. The variation between these species is 80.01% of total variation; approximately six times higher than the variation among the populations within species. The genetic divergence between species is 7.02% in long sequences and 7.46% in short ones. The genetic divergence within species is 1.18% in S. reptans and 0.83% in S. reptantoides in long sequences, and 1.38% and 1.05% in short sequences. Maximum likelihood trees, maximum parsimony trees and the haplotype network constructed using TCS showed that each species consists of two units, labelled as A and B forms. The distribution of the S. reptans forms is not identical-in Slovakia and the Baltic area only S. reptans B was found, meanwhile both A and B forms were present in Great Britain and Sweden; with the A form clearly dominant. In contrast, both forms of S. reptantoides were present in Great Britain and Slovakia, and absent in Scandinavia and the Baltic area. Additional studies comprising more individuals from larger areas of Europe are required to verify the taxonomic position of these species' forms.

Cladistic analysis of self-grooming indicates a single origin of eusociality in corbiculate bees (Hymenoptera: Apidae).

Behavioural traits have been used extensively in recent years as an important character source for making phylogenetic inferences. The phylogenetic positions of the members of the Apini subtribe are increasingly being debated, and new characters must be examined. We analysed the presence and absence of certain behavioural patterns, as well as the sequences of some of these patterns, to generate 79 characters. Eleven species comprised the ingroup, and Xylocopini comprised the outgroup. Parsimony analysis showed that the most parsimonious tree was (Euglossina(Bombina(Apina+Meliponina))). This topology is consistent with most studies that use morphological data and the few that use behavioural data, which suggests that advanced eusociality arose only once in a common ancestor of the clade Apina plus Meliponina; however, this hypothesis is inconsistent with our molecular data. Thus we considered behavioural, molecular, and morphological data and recovered the same topology, in which eusociality has a single origin in corbiculate bees.

Molecular and morphological variability within the Aphidius colemani group with redescription of Aphidius platensis Brethes (Hymenoptera: Braconidae: Aphidiinae).

We have identified the following three taxa related to the Aphidius colemani species group, which are important biological control agents: Aphidius colemani, Aphidius transcaspicus and Aphidius platensis. Using partial sequences of the mitochondrial cytochrome oxidase subunit I (mtCOI) gene and geometric morphometric analysis of the forewing shape, we have explored the genetic structure and morphological variability of the A. colemani group from different aphid host/plant associations covering a wide distribution area. The topology of the maximum parsimony and maximum likelihood trees were identical with 98-100% bootstrap support, clustering A. colemani, A. platensis and A. transcaspicus into separate species. The distances among the taxa ranged from 2.2 to 4.7%, which is a common rate for the between-species divergence within the subfamily Aphidiinae. Differences in the shape of the forewing investigated within the biotypes of A. colemani group are congruent with their genetic diversification. Both A. platensis and A. colemani share a common host range pattern, and it would be interesting to estimate and compare the role of these two species in future biological control strategies against aphids of economic importance. Our results indicate that 'genetic screening' is a reliable approach for identification within the A. colemani group. The high variation in the wing shape among species, including a significant divergence in the wing shape among specimens that emerged from different hosts, makes the forewing shape and wing venation less reliable for species determination. Aphidius platensis is diagnostified and redescribed, and the key for the A. colemani group is presented.

Phylogenetic relationships among genera of the tribe Cnephasiini (Lepidoptera: Tortricidae: Tortricinae) based on morphological characters of adults

A phylogenetic analysis was conducted on the moth tribe Cnephasiini based on 83 morphological characters of adults (63 binary and 20 multistate). The analysis included 26 species representing 20 genera, plus two outgroup representatives of the tribe Tortricini. The cladistic analysis resulted in the 10 most parsimonious trees. The tribe Cnephasiini was recovered as monophyletic; the genus Cnephasia was not recovered as monophyletic; the New World Decodes clustered with the primarily Old World Cnephasia; Oxypteron is best treated as monotypic (with the single species palmoni), and Amphicoecia adamana, Oporopsamma dunaria and O. wertheimsteini should be assigned to a different genus; Propriomorpha and Xerocnephasia were the most basal groups; Exapate duratella and Epicnephasia mongolica were recognised as sister-groups; and Kawabeia was closest to Tortricodes.

Floral Evolution in the Detarieae (Leguminosae): Phylogenetic Evidence for Labile Floral Development in an Early-Diverging Legume Lineage

Premise of research. We examine floral evolution and phylogenetic relationships in the monophyletic Detarieae and related lineages of Caesalpinioideae. Tribe Detarieae (82 genera) includes nearly half of the genera in subfamily Caesalpinioideae and represents some of the most diverse legumes with respect to floral morphology.Methodology. A total of 67 floral ontogenetic and morphological characters were combined with DNA sequences from the plastid trnL-F and matK regions of 34 Detarieae species and representatives of Cassieae, Cercideae, Caesalpinieae, Papilionoideae, and Mimosoideae, for which we have near-complete ontogenetic series. The morphological and ontogenetic characters were optimized onto the resulting most parsimonious phylogenetic trees and Bayesian topology to study character evolution.Pivotal results. Our study supports previously proposed relationships within the tribe Detarieae and among caesalpinioid lineages and indicates that certain features (bracteole and hypanthium characters, sepal initiation, anther position in bud, overlap in timing of initiation of organ whorls) are phylogenetically informative for particular clades whereas others (reductions in petal and stamen number, sepal and petal initiation patterns) have evolved multiple times in parallel in the Detarieae and other Caesalpinioideae. These analyses suggest that modifications that occur early in ontogeny can be good phylogenetic characters for distinguishing both major taxonomic groups and more closely related taxa and that morphological differences that differentiate species within genera can be caused by changes that occur at all stages of ontogeny. Phylogenetic distribution of character states and ontogenetic evidence suggest that in the Caesalpinioideae, loss or suppression of organs within a whorl, both of which are very common, usually does not affect development in subsequent whorls.Conclusions. Our analyses reveal several switches from zygomorphy to actinomorphy (and vice versa), but in Caesalpinioideae (contrary to Papilionoideae), zygomorphy is likely not clearly associated with higher diversification rates. This study suggests that floral initiation patterns are much more variable in Caesalpinioideae than in the other two subfamilies. Although particular patterns may be canalized in certain lineages of the subfamily (Cercideae, Caesalpinieae), in other clades (Detarieae, Dialiinae) floral development is more labile, explaining the high diversity in floral morphology encountered overall in the paraphyletic Caesalpinioideae.

Is morphology supporting a monophyletic Proustia Lag., (Nassauvieae, Asteraceae)?

Proustia is an Andean genus traditionally considered to have three species and ten infraspecific taxa, which has often been placed in tribes other than Nassauvieae mainly because of its distinctive style features. Currently, each of the three species of Proustia is included in its own section denoting a consistent morphological variability within the genus. The heterogeneity among Proustia species mainly relies on habit, spiny structures arrangement, capitula arrangement, and pappus features. On the contrary, the forms or varieties within each species are apparently more homogeneous. The phylogenetic analysis performed here is based on morphological features and includes all the species, and all but two varieties and forms of Proustia. We test the boundaries of Proustia and the hypothesis that morphological discontinuities in the genus are phylogenetically uninformative. A total of 26 taxa and 29 morphological, anatomical, and palynological characters were studied. A maximum parsimony analysis yield six most parsimonious trees that showed almost identical topologies. Our results do not support the current generic concept of Proustia. Independently, each species of Proustia was monophyletic when taxa at sub-specific level were considered. Proustia pyrifolia was retrieved sister to the genus Berylsimpsonia although this clade did not obtain significant support. The spiny structures usually referred to as diagnostic for Proustia are not homologous for the genus. Characteristics of habit, spiny structures, secondary inflorescences and pappus support clades representing each species of Proustia, which may in turn, represent different genera.

Morphology-Based Phylogeny and Biogeography of Wockia (Lepidoptera: Urodidae) with Description of a New Species from Japan and South Korea

Wockia, one of the six genera within the lepidopteran family Urodidae, currently includes nine species distributed in Holarctic, Oriental, and Neotropical regions. A new species of the genus, W. magna sp. nov., is described from Japan and South Korea. This is the first record of Urodidae from Japan. A cladistic analysis was constructed based on 27 morphological characters from five ingroup species and two outgroup taxa. A single most parsimonious tree was found (length = 38, CI = 71, RI = 70). The resulting tree failed to recover the monophyly of Wockia chewbacca and a clade Wockia sensu stricto, including four congeners from North America, temperate East Asia and Southeast Asia. Wockia sensu stricto was resolved as monophyletic and was divided into two subgroups, one including W. asperipunctella and W. magna, and the other including W. koreana and W. variata. The sister-group relationship of W. asperipunctella and W. magna was moderately supported. Synapomorphies of Wockia sensu stricto are provided from the resulting phylogeny. Systematic definitions of Wockia and other allied genera are revised. Optimal ancestral area reconstruction implemented in DIVA resulted in different hypotheses for Wockia, depending on how to constrain the maximum number of areas. The maximum area number set as two yielded a more likely scenario suggesting that Wockia sensu stricto originated in temperate East Asia and then dispersed into the Oriental region, North America, and Europe. A working hypothesis and other equally possible alternative explanations for the biogeography of Wockia are provided.

Cloning and sequence analysis of the partial mitochondrial rrnL gene of Trichuris ovis isolates in China

The purpose of this study was to analyze sequence variation in the partial mitochondrial ribosomal large subunit gene(prrnL) among Trichuris ovis(T.ovis) isolates from Guangdong province,China and to study the phylogenetic relationships of T.ovis with other whipworms using prrnL sequences.The prrnL sequences were amplified from individual T.ovis samples by polymerase chain reaction(PCR) method and the obtained prrnL sequences were aligned using ClustalX 1.81.Maximum parsimony(MP) tree was constructed using the software PAUP 4.0 Beta 10.The lengths of all prrnL were 849 850 bp,and differences in prrnL sequences within T.ovis were 0 0.8%.Phylogenetic analyses showed that all T.ovis isolates were clustered in the same clade.The prrnL sequences were quite conserved within whipworm species while inter-species differences(33.4% 36.1%) were obvious.Thus prrnL sequences can be used as a useful marker for the differentiation and identification of different whipworms.

A taxonomic revision of the genus Edosa Walker, 1886 from China (Lepidoptera, Tineidae, Perissomasticinae).

The genus Edosa Walker, 1886 is revised in China. Of the 31 recognized species, 23 are described as new: Edosa aurea sp. nov., E. baculiformis sp. nov., E. bicolor sp. nov., E. bifurcata sp. nov., E. carinata sp. nov., E. conchata sp. nov., E. cornuta sp. nov., E. curvidorsalis sp. nov., E. dentata sp. nov., E. digitata sp. nov., E. duoprojecta sp. nov., E. elongata sp. nov., E. eminens sp. nov., E. hamata sp. nov., E. longicornis sp. nov., E. minuta sp. nov., E. robinsoni sp. nov., E. robustispina sp. nov., E. semicircularis sp. nov., E. torta sp. nov., E. truncatula sp. nov., E. uncusella sp. nov., and E. varians sp. nov.; Edosa gaedikei nom. nov. is proposed as a replacement name for Edosa spinosa Gaedike, 2012, a junior homonym of Edosa spinosa Gaedike, 1984; four species are newly recorded for China: E. hendrixella Robinson, 2008, E. crayella Robinson, 2008, E. orphnodes (Meyrick, 1911) and E. smithaella Robinson, 2008; the female of E. hendrixella is described for the first time. Phylogenetic relationships of the Chinese species, except E. malthacopis (Meyrick, 1936), are postulated based on 42 morphological characters. The phylogenetic analysis of the morphology matrix yielded one most parsimonious tree (length 121 steps, CI = 0.56, RI = 0.81), based on which seven species-groups are proposed: the hemichrysella-group, the subochraceella-group, the pyrochra-group, the duoprojecta-group, the eminens-group, the crayella-group and the uncusella-group. The whole body structures of the genus are presented and photographs of adults and genitalia are provided, along with a key to all the known Chinese species and maps to show the distribution of Edosa in China. A world checklist of Edosa is given as an appendix, in which 41 new combinations are included.

Mitochondrial COI and morphological evidence for host specificity of the black cherry aphids Myzus cerasi (Fabricius, 1775) collected from different cherry tree species in Europe (Hemiptera, Aphididae)

Partial sequences of the mitochondrial COI gene of forty eight European and two Turkish population samples of Myzus cerasi from different winter hosts (Prunus spp.) were subjected to phylogenetic analyses. The analysed M. cerasi samples emerged as paraphyletic relative to a Myzus borealis sample used as an out-group, and formed two major clades in neighbor joining, maximum parsimony, maximum likelihood and Bayesian inference trees, corresponding to subspecies living specifically on Prunus avium and P. cerasus. Multivariate discriminant analysis (method of canonical variates) was applied to find out if morphological variation of samples correlated with mitochondrial COI and host plant information. Mean scores on the first two canonical variables clustered samples fully in accordance with their COI haplotypes and host plants confirming the existence of two morphologically similar winter host - specific subspecies of M. cerasi in Europe. No single morphological character enabled satisfactory discrimination between apterous viviparous females of the two subspecies. A three-character linear discriminant function enabled 92.37% correct identification of apterous viviparous females of M. cerasi cerasi (n = 118) and 93.64% of M. cerasi pruniavium (n = 110). A key for the morphological identification of the two subspecies is presented and their taxonomic status is discussed.