Karyology of some Brazilian species of Alismataceae

The family Alismataceae ( sensu Cronquist) comprises 11 genera and 75 species of aquatic and semiaquatic herbs. In Brazil, only the two most speciose genera, Echinodorus Rich. ex Engelm. and Sagittaria L., are present. The chromosome number 2 n  = 22 is common to all species. We present karyotypes for eight species, together with their asymmetry index (TF%) and total chromatin length (TCL). All karyotypes have high karyotypic asymmetry and TCL, due to their large and mostly acrocentric chromosomes. The chromosomal evolution of the Alismatidae group is discussed.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 143 , 159−164.     

Karyological studies in Jaborosa (Solanaceae)

Sixteen species of Jaborosa (Solanaceae), including eight endemic to Argentina, were studied karyologically. The numbers n  = 12 and/or 2n  = 24 were found in all species, the majority of the cases being new reports. Mitotic chromosomes were small- to medium-sized, the average length varying from 2.95 to 4.93 µm. All species had one to three chromosome pairs with satellites. The karyotypes, obtained for 13 species, were slightly asymmetrical: A ₁ ranged from 0.228 to 0.483, A ₂ ranged from 0.095 to 0.182, and Paszko's asymmetry index ranged from 0.84 to 3.47. In all species, metacentric chromosomes were the most common, followed by submetacentrics, but subtelocentrics were rare. Morphological similarities and sectional arrangements were not reflected in either a principal components analysis plot or asymmetry index plot, but the species could be singled out by their karyotype formulae and the different karyotype parameters taken. In Jaborosa , a notably diversified genus, exo-morphological evolution has taken place, together with evident chromosome rearrangements, whose disposition is different and not as clear as in related genera.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 156 , 467–478.     

Karyotype analysis in South American species of Myrtaceae

In Myrtaceae (Myrteae), the diploid chromosome number 2 n  = 2 x  = 22 is the most common, although variations of ploidy level occur, with some triploid (2 n  = 3 x  = 33) and tetraploid (2 n  = 4 x  = 44) records. Karyotype details in this group are scarce because the chromosomes are small (< 2 μm). In this work, we carried out a karyotypic analysis of 15 species of Myrtaceae grouped in different subtribes and genera. Measurements of chromosome length (long arm, L ; short arm, S ) were taken and several karyotypic parameters were calculated for each species. The karyotypes in fleshy-fruited taxa (Myrteae) were more varied than in the other previously analysed dry-fruited group ( Eucalyptus , Eucalypteae), in which the chromosomes were exclusively metacentric.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 155 , 571–580.     

Chromosome number, karyotype, and taxonomic considerations on the enigmatic Sellocharis paradoxa Taubert (Leguminosae, Papilionoideae, Genisteae)

Until recently, Sellocharis paradoxa Taubert, the only species of this Genisteae genus, was known solely by the isotypes. Recent new collections in Rio Grande do Sul, southern Brazil, have enabled data on chromosome number and karyotype morphology to be obtained for the first time. S. paradoxa has 2 n  = 20 chromosomes, and a bimodal asymmetrical karyotype, composed of one pair of long ( c . 6.3 µm) metacentric, five pairs of shorter acrocentric, and four pairs of shorter telocentric chromosomes ranging from c . 3.7 to 2.7 µm. The chromosome number and karyotype morphology of S. paradoxa do not fit into the Genisteae pattern. Existing information is so far insufficient to answer evolutionary questions about its origin and phylogenetic relationships, but the uniqueness of this taxon, first indicated by its peculiar leaf arrangement, and now supported by its uncommon karyological constitution, strongly suggests that the suprageneric taxonomic position of S. paradoxa should be re-evaluated.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 155 , 223–226.     

Polymorphism of the Sphaerium corneum (Bivalvia, Veneroida, Sphaeriidae) revealed by cytogenetic and sequence comparison

Two populations of Sphaerium corneum were sampled from River Vilnelė and small pond in Vilnius, Lithuania. The chromosomes were studied using conventional Giemsa staining and karyometric analysis. Inter- and intra-individual variation in the diploid chromosome numbers was revealed and two different sources of chromosome variability were identified: B chromosomes and the structural changes of chromosomes of the basic (A) set. The chromosome set of the more common karyotypic form, 2 n  = 30, found in both populations, consists of all biarmed metacentric and meta-submetacentric chromosomes of gradually decreasing size. Small, biarmed, mitotically unstable B chromosomes were found in the cells of this karyotypic form. Specimens with 2 n  = 36 were found only in pond. No B chromosomes were detected in their cells. The karyotype is characterized by presence of two pairs of medium telocentrics and four pairs of small subtelocentrics. The remaining chromosomes are biarmed. Robertsonian fusions appear to be involved in formation of two karyotypic forms of S. corneum . DNA sequence analyses showed that ITS1 is identical in both karyotypic forms. On the other hand, differences in 16S sequence were revealed and two haplotypes, corresponding to two karyotypic forms, were identified. The present study opens new perspectives in establishing species-specific characters for confident identification of Sphaerium species and provides insights to the genetic intraspecific variability and possible mechanisms of speciation.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 89 , 53–64.     

A new annual species of Bellium (Asteraceae) from the Balearic Islands

A new species, Bellium artrutxensis (Asteraceae: Astereae), is described from the therophytic pastures of southern Minorca (Balearic Islands). The analysis of nuclear ribosomal internal transcribed spacer (ITS) sequences showed that the new taxon was closely related to Bellium bellidioides , but differed with regard to the annual lifespan, the absence of epigeal stolons, and the presence of a patent eglandular indumentum on the leaves. The new taxon shows morphological features that are well suited for the colonization of dry environments with a marked summer drought, and may be of adaptive significance. The new species is diploid (2 n  = 18) and shows up to two accessory chromosomes in root tissues. B chromosomes have not been reported previously in other species of Bellium .  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 154 , 65–77.     

Cytotaxonomy of Lychnophoriopsis Sch.Bip. and Paralychnophora MacLeish species (Asteraceae: Vernonieae: Lychnophorinae)

The genera Lychnophoriopsis and Paralychnophora are endemic to Brazilian 'campo rupestre' in the States of Minas Gerais and Bahia. To analyse the status of the cytotaxonomy of these genera, we carried out chromosome counts on several species. Two chromosome numbers were obtained for four species of Paralychnophora : 2 n  = 36 and 2 n  = 38. For three species of Lychnophoriopsis , only 2 n  = 36 was observed. The chromosome size (1.0–2.58 µm) and morphology (mainly metacentric, with some submetacentric) were analysed in four species of Paralychnophora and showed relative constancy .   © 2007 The Linnean Society of London. Botanical Journal of the Linnean Society , 2007, 154 , 109–114.     

Karyomorphology of the endangered Trigonobalanus doichangensis (A. Camus) Forman (Fagaceae) and its taxonomic and biogeographical implications

Cytological studies were carried out for the first time on five populations of Trigonobalanus doichangensis in China and Thailand. In all populations, the pattern of interphase nuclei was of the simple chromocentre type, the mitotic prophases were of the proximal interstitial type and chromosome numbers were 2 n  = 2 x  = 14. Two B chromosomes were commonly observed at prophase and prophase–metaphase, but rarely at metaphase. Karyotype variation among the populations at the diploid level was limited, but there were some distinguishing cytological characters. Based on the comparison of all the available data on cytology, taxonomy, phytogeography and molecular systematics related to the genus Trigonobalanus , we recommend that the three species of Trigonobalanus comprise the subfamily Trigonobalanoideae and that the genus should not be segregated into three monotypic genera.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 154 , 321–330.     

Cytogenetic studies of four South American species of Paullinia L. (Sapindaceae)

Four South American species of Paullinia ( P. elegans , P. meliaefolia , P. pinnata , and P. rhomboidea ) were compared using conventional chromosome staining, C-Giemsa and C-chromomycin A₃/4',6-diamidino-2-phenylindole (C-CMA₃/DAPI) banding, and fluorescence in situ hybridization (FISH) with a 45S ribosomal DNA (rDNA) probe. All species showed a somatic complement of 2 n  = 24 chromosomes, agreeing with earlier records in some cases, and showing a tendency for the chromosome number to be conserved in this genus. The chromosome number of P. rhomboidea is a new report. The karyotypes differed in chromosome size and degree of karyotype asymmetry. The chromosomal band patterns and location of the 45S rDNA sites are reported for the first time in the genus. Terminal C-CMA₃ bands were associated with the 45S rDNA sites, but varied in number and size between the species. The occurrence of other C-Giemsa bands that were not revealed by CMA₃ suggests that more than one family of repetitive DNA may be involved in karyotype differentiation. The systematic implications of these results on the infrageneric relationships are discussed.   © 2007 The Linnean Society of London . Botanical Journal of the Linnean Society , 2007, 154 , 313–320.     

Relationships in Patagonian species of Berberis (Berberidaceae) based on the characterization of rDNA internal transcribed spacer sequences

Sequence analysis of the internal transcribed spacer (ITS) of the 18S(ITS1)-5.8S-26S(ITS2) rDNA region was performed in order to analyse the phylogenetic relationships between 13 Patagonian species of the genus Berberis (Berberidaceae). The divergence values between the pairwise sequence in the studied Patagonian species were in the range 2.9–22.9%. The lengths of the ITS1 and ITS2 sequences were in the range 227–231 bp and 220–224 bp, respectively, and the 5.8S sequence was 159 bp throughout all species . B. microphylla sensu Landrum does not appear to be monophyletic based on current sampling. Indeed, we suggest that B. microphylla should be distinguished from B. buxifolia , B. parodii , and B. heterophylla . ITS sequences, together with data obtained from morphological, biochemical, amplified fragment length polymorphism, and cytological characterizations, support the existence of diploid and polyploid hybrid speciation in the genus.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 153 , 321–328.     

Karyotype evolution in the genus Boronia (Rutaceae)

New chromosome counts are reported for Boronia clavata 2 n  = 14, B. heterophylla 'Near White' 2 n  = 15, B.  'Carousel' 2 n  = 16, B. deanei 2 n  = 22, B. chartacea 2 n  = 32, B. keysii 2 n  = 32, B. pilosa 2 n  = 44, B. anethifolia 2 n  = 36 and B. citriodora 2 n  = 108. Studies in 20 genotypes of 18 species and one interspecific hybrid revealed that they are highly complex in terms of chromosome number, ploidy level, chromosomal length, karyotype constitution and asymmetry. Karyotype analysis indicated that Boronia taxa with high chromosome numbers are primitive and those with lower numbers are derived. The basic chromosome number for this genus is suggested to be x = 18. Analysis of chromosome number, variations of total chromosome length (TCL) and average chromosome length (ACL), Nombre Fondamental (NF) and karyotype asymmetry suggest that dysploid reduction is the major mechanism in Boronia karyotype evolution. Chromosomal rearrangements might also have been involved. Origin, chromosome number changes and spread of Boronia are discussed in relation to the species divergence and the geological and climatic changes of the Australian continent.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 142 , 309–320.     

Cytotaxonomic analysis of South American species of Vernonia (Vernonieae: Asteraceae)

Chromosome numbers in 48 populations belonging to 31 species of Vernonia from South America have been determined. First chromosome counts are reported for V. propinqua var. canescens (2 n = 20), V. sceptrum (2 n = 80), V. rufogrisea (2 n = 32), V. heringeri (2 n = 32), V. hovaefolia (2 n = 64), V. hystricosa (2 n = 128), V. obtusata (2 n = 64), V. pseudoincana (2 n = 32), V. rubricaulis var.◊ australis (2 n = 64) and V. rugulosa (2 n = 30). The basic chromosome numbers x = 10, 14, 15, 16 and 17 were confirmed for New World species of Vernonia . Together with previous records, these numbers suggest that the evolution of Vernonieae has occurred through a combination of polyploidy and aneuploidy. Taxonomic implications of certain counts are also discussed.  © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 139 , 401–408.     

Incipient speciation revealed in Anastrepha fraterculus (Diptera; Tephritidae) by studies on mating compatibility, sex pheromones, hybridization, and cytology

It has long been proposed that the nominal species Anastrepha fraterculus is a species complex and earlier studies showed high levels of pre-zygotic isolation between two laboratory strains from Argentina and Peru. Further experiments were carried out on the same populations and on their reciprocal hybrids, including pre- and post-zygotic isolation studies, pheromone analysis, and mitotic and polytene chromosome analysis. A high level of pre-zygotic isolation had been maintained between the parental strains despite 3 years of laboratory rearing under identical conditions. The level of pre-zygotic isolation was reduced in matings with hybrids. There were also differences in other components of mating behaviour. There were quantitative and qualitative differences in the sex pheromone of the two strains with the hybrids producing a mixture. The pre-zygotic isolation barriers were complemented by high levels of post-zygotic inviability and sex ratio distortion, most likely not due to Wolbachia , although there was evidence of some cytoplasmic factor involved in sex ratio distortion. Analysis of polytene chromosomes revealed a high level of asynapsis in the hybrids, together with karyotypic differences between the parental strains. The combined results of the present study indicate that these two strains belong to different biological entities within the proposed A. fraterculus complex.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 97 , 152–165.     

Chromosomal variability in the genus Primula (Primulaceae)

Chromosome numbers and measurements were recorded in 47 individuals of ten taxa of Primula , representing eight species and two subspecies from ten populations. The basic numbers of chromosomes were x  = 8, 9 or 11, and they were mostly metacentric, medium-long to medium-small, ranging in length from c . 3.6 µm to 1.6 µm. Diploid chromosome numbers of 2 n  = 2 x  = 24 and 22 were scored for the first time in P. loeseneri Kitag. and P. prenantha Balf. & Sm., respectively. A new ploidy level of 2 n  = 4 x  = 44 was found in P. burmanica Balf. & King. The recorded diploid numbers of the remaining species confirmed earlier reports. Interspecific variability in chromosome numbers was correlated with heterogeneity in their mean length. Comparison of the data with those in the literature revealed that the observed variability of chromosomal characters was compatible with the other taxonomic criteria and supports the current taxonomic delimitation. Chromosomal variation at the diploid level is the predominant feature in Primula evolution, and allopatric speciation has played a major role in its specific diversity. Subgen. Aleuritia could represent the main clade from which the other subgenera have evolved. The origin of the chromosome numbers, geographical distribution and evolution of the species were assessed, and the parallel polyphyletic mode of evolution in the genus was confirmed.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 150 , 211–219.     

Uniformity of karyotypes in Ligularia (Asteraceae: Senecioneae), a highly diversified genus of the eastern Qinghai–Tibet Plateau highlands and adjacent areas

Ligularia , a highly diversified genus in the eastern Qinghai–Tibet Plateau and adjacent areas, was chosen as a suitable subject in which to study speciation patterns in this 'hot spot' area at the chromosomal level. Chromosome numbers and karyotypes were studied in 23 populations of 14 species, most of which are endemic to this area. The basic number x  = 29 was confirmed for all species. Ligularia virgaurea was found to have diploid and triploid cytotypes, 2 n  = 58 and 87. Other species are only diploid, with 2 n  = 58. The karyotypes of all populations within any species, and all species spanning most sections and covering most of the morphological range in Ligularia , are very similar to each other, belonging to type 2A according to Stebbin's classification. This karyotype was also found in its close allies, e.g. Cremanthodium , Ligulariopsis , Parasenecio , and Sinacalia . Aneuploid reduction of chromosome number from 2 n  = 60 to 58 and karyotypic variation was found in Ligularia and its allies. Such a chromosomal pattern with few polyploids infers that variation of karyotype structure at the diploid level seems to be the predominant feature of chromosomal evolution in this group and sympatric speciation via hybridization and polyploidization has played a minor role in its species diversity.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 144 , 329–342.     

A new species of Astragalus L. (Leguminosae) from India based on morphological and molecular markers

A new species, Astragalus himachalensis , is described and illustrated from the Himalaya in India. The species grows occasionally in different parts of the cold desert of Lahul-Spiti (Himachal Pradesh). It resembles A. himalayanus , but differs chiefly in the small size of the plants (length, 5–15 cm), diadelphous stamens, and small pods (length, 5–6 mm) with the stipe length (2–3 mm) more or less equal to the calyx length. The similarities and significant differences between A. himachalensis and A. himalayanus were confirmed by analyses of random amplification of polymorphic DNA (RAPD) and directed amplification of minisatellite DNA (DAMD) markers. RAPD and DAMD methods clearly distinguished between the two species and were in congruence with morphological markers. © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 154 , 27–34.     

Cytotaxonomy of Begonia rubropunctata and B. purpureofolia (Begoniaceae)

The chromosome numbers of four Chinese Begonia species were counted for the first time as follows: 2 n  = 22 in B. rubropunctata , 2 n  = 18 in B. purpureofolia , 2 n  = 44 in B. pedatifida , and 2 n  = 22 in B. villifolia . The first two species had relatively large chromosomes with early condensed chromatin in the distal and interstitial or proximal regions, whereas the last two had small chromosomes with early condensed chromatin in the proximal regions. Although they have been reduced in the literature to synonyms of B. pedatifida and B. villifolia , respectively, B. rubropunctata and B. purpureofolia should be treated as distinct species because of the differences in chromosome numbers and other chromosome features.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 155 , 513–517.     

Assemblage and population-level consequences of forest fragmentation on bilateral asymmetry in tropical montane birds

Habitat fragmentation has the potential to influence the development and thus the phenotype of organisms. The asymmetry of bilateral traits may be indicative of the extent to which developmental stability is compromised by the stressful conditions underlying fragmentation. Using an assemblage- and population-level approach, we explored asymmetry differences in tarsus and outermost tail feathers of birds inhabiting fragmented landscapes in the tropical Andes of Colombia. More than 2500 individuals of 185 species were mist-netted at nine forest sites representing continuous forest (> 1000 ha), medium- (70–110 ha), and small-sized (8–20 ha) fragments. Feathers showed true fluctuating asymmetry (FA), whereas tarsus presented a mixture of FA and directional asymmetry. Overall, asymmetry was lowest in continuous forest, and highest in small and medium fragments. These patterns remained unchanged when directionality and differences in species composition, abundance, and foraging tactics were considered. The population-level analyses showed a general trend of increased asymmetry variation in fragments, yet the responses were not always in the same direction. Increased asymmetry may represent an outcome of processes that contribute to the persistence of species in changing environments, and to the generation of phenotypic innovation, which suggests individual adjustments of development to deal with stress. This calls into question the deliberated application of FA as a biomonitoring tool for conservation.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 92 , 119–133.     

Epidendrum caparaoense (Orchidaceae), a new species from Minas Gerais, Brazil

A new species of Orchidaceae, Epidendrum caparaoense W.Forst. & V.C.Souza, is described and illustrated. This species is known only from the type locality, Caparaó National Park, in Minas Gerais State, where it grows on low tree trunks in gallery forests, at approximately 1300 m. The taxon is distinct from the other species of the genus by its laterally compressed stems, a long tubular spathaceous bract at the base of the inflorescence, a labellum with the free portion three-lobed and the clinandrium with an entire margin. It is considered similar to E. geniculatum and E. hololeucum .  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 155 , 157–159.     

Amana kuocangshanica (Liliaceae), a new species from south-east China

Amana kuocangshanica D. Y. Tan & D. Y. Hong is described as a new species from Mt. Kuocang, Zhejiang Province, south-east China. Morphological observations and a statistical analysis of the new species and its relatives show that it is most closely related to A. anhuiensis and A. erythronioides , but differs in having the lower leaf oblanceolate, the widest at two-thirds length from the base, tunics glabrous inside, and fruit beaks 5–7.5 mm long. The morphologies of the pollen, seeds, and epidermal cells of the leaves of this new species are described.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 154 , 435–442.