利用低拷贝核基因重建菊科紫菀亚科族间系统发育关系

紫菀亚科(Asteroideae)是菊科最大的一个亚科, 包含的种数多于被子植物的绝大多数科。目前, 紫菀亚科族间的系统发育关系主要依赖于叶绿体基因信息, 但是叶绿体基因为单亲遗传, 并不能完整反映进化历史。鉴于杂交现象在菊科普遍存在, 故利用核基因可以反映更完整的紫菀亚科进化历史。该研究首次使用从转录组数据(20个新测+11个从NCBI数据库下载)中筛选出的47个直系同源低拷贝核基因来研究紫菀亚科的系统发育关系, 共选取了29个物种, 代表了紫菀亚科20个族中的13个族。用超矩阵分析方法和溯祖推测分析方法各获得了1个稳定的紫菀亚科系统树, 每个树上绝大多数分支都得到了高度支持, 且2个树之间没有明显的冲突。新的紫菀亚科族间系统发育关系揭示了千里光超族应并入紫菀超族, 春黄菊族可能是千里光族与紫菀族杂交起源的, 金鸡菊族很可能也是杂交起源的。该研究结果显示低拷贝核基因可以更好地解决科以下分类阶元的系统发育关系, 对菊科乃至被子植物其它科的系统发育研究具有重要的借鉴意义。     

Pollen hosts of western palaearctic bees of the genus Colletes (Hymenoptera: Colletidae): the Asteraceae paradox

To assess the pollen hosts of 60 western palaearctic bee species of the genus Colletes (Colletidae), we microscopically analysed 1336 pollen loads of collected females. Twenty‐six species (43.3%) were found to be specialized at the level of plant family, subfamily or genus. Thirty‐four species (56.7%) proved to be pollen generalists to varying degrees, visiting the flowers of up to 15 different plant families. Flowers of the subfamily Asteroideae (Asteraceae) are by far the most important pollen source, contributing 23.6% to the pollen‐plant spectrum of the whole bee genus. The high significance of Asteroideae pollen is due to the large number of specialists: 14 Colletes species belonging to four different taxonomic groups harvest pollen exclusively or predominantly on flowers of the Asteroideae. By striking contrast, Asteroideae pollen plays only a marginal role in the diets of the pollen generalists: it was recorded in only 2.7% of the pollen loads and in seven out of the 34 pollen generalists. Among the few generalists exploiting Asteroideae for pollen, three closely related species have ancestors which were possibly specialized on Asteraceae. The pattern of use of Asteroideae pollen by the Colletes bees supports recent findings that this pollen possesses unfavourable or protective properties, which render its digestion difficult, and suggests that bees need physiological adaptations to successfully utilize it. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95 , 719–733.     

A comprehensive generic-level phylogeny of the sunflower family: Implications for the systematics of Chinese Asteraceae

The sunflower family (Asteraceae) is the largest and the most diverse flowering plant family, comprising 24 000–30 000 species and 1600–1700 genera. In China, Asteraceae are also the largest family, with approximately 2336 indigenous species in 248 genera. In the past two decades, molecular phylogenetic analyses has contributed greatly to our understanding of the systematics of Asteraceae. Nevertheless, the large-scale analyses and knowledge about the relationships of Chinese Asteraceae at the generic level as a whole are far from complete due to difficulties in sampling. In this study, we presented a three-marker (rbcL, ndhF, and matK) phylogeny of Asteraceae, including 506 genera (i.e., approximately one-third of Asteraceae genera). The study sampled 200 Chinese genera (i.e., approximately 80% of Chinese Asteraceae genera). The backbones of the new phylogeny were largely congruent with earlier studies, with 13 subfamilies and 45 tribes recognized. Chinese Asteraceae were distributed in 7 subfamilies (Mutisioideae, Wunderlichioideae, Carduoideae, Pertyoideae, Gymnarrhenoideae, Cichorioideae, and Asteroideae) and 22 tribes (Mutiseae, Hyalideae, Cardueae, Pertyeae, Gymnarrheneae, Vernonieae, Cichorieae, Doroniceae, Senecioneae, Astereae, Anthemideae, Gnaphalieae, Calenduleae, Inuleae, Athroismeae, Helenieae, Coreopsideae, Neurolaeneae, Tageteae, Millieae, Eupatorieae, and Heliantheae). Chinese Asteraceae lacked 6 basal subfamilies and 23 tribes. Several previously ambiguous relationships were clarified. Our analyses also resolved some unplaced genera within Chinese Asteraceae. Finally, our phylogenetic tree was used to revise the classification for all genera of Chinese Asteraceae. In total, 255 genera, 22 tribes, and 7 subfamilies in China are recognized.     

Evolution of sesquiterpene lactones in angiosperms

The paper attempts to discover an outline of the evolutionary trends of sesquiterpene lactones in angiosperms. The working method involves the quantification of skeletal specialization and oxidation state of the compounds and the assignment of evolutionary advancement indices, based on such data, to taxa. In the angiosperms as a whole, sesquiterpene lactone evolution proceeds by diversification of structural types and by amplification of the oxidation state of the molecules. The opposite trend appears to operate at lower hierarchical level, in the Asteraceae. In this family, which contains most of the known compounds of the class, sesquiterpene lactone evolution follows two parallel pathways in the tribes belonging to two groups of the subfamily Asteroideae.     

Contribution to the genome size knowledge of New World species from the Heliantheae alliance (Asteraceae)

This article contributes first genome size assessments by flow cytometry for 16 species, 12 genera, and 3 tribes from family Asteraceae, mostly belonging to the Heliantheae alliance, an assembly of 13 tribes from subfamily Asteroideae with a large majority of its species in the New World. Most genome sizes are accompanied by their own chromosome counts, confirming in most cases, although not all, previous counts for the species, and revealing possible cases of unknown dysploidy or polyploidy for certain taxa. The data contribute to the pool of knowledge on genome size and chromosome numbers in the family Asteraceae and will further allow deeper studies and a better understanding on the role of dysploidy in the evolution of the Heliantheae alliance. However, we still lack data for tribes Chaenactideae, Neurolaeneae, Polymnieae, and Feddeeae (the latter, monospecific) to complete the alliance representation.     

TRIBAL INTERRELATIONSHIPS OF THE ASTERACEAE

Abstract— A cladistic analysis involving 27 tribes and subtribes of Asteraceae and 81 characters is presented. The terminal taxa are mainly those of present tribal classification, though some apparently poly- and paraphyletic tribes, notably the Mutisieae and the Inuleae, have been represented by sub-tribal taxa. Characters are assembled from all available sources. Corolla types, styles and stamens have provided many characters. The Lobeliaceae are used as an outgroup and are considered as the most probable sister group of the Asteraceae. There is a basal dichotomy in the family, the Mutisieae-Barnadesiinae being the monophyletic sister group of the remaining major, also monophyletic part of the family. The recent family division into two subfamilies about equal in size, the Cichorioideae and the Asteroideae, neither represents a basal dichotomy nor a sister group relationship within the Asteraceae. The Asteroideae are monophyletic and have their sister group within the paraphyletic Cichorioideae. Interrelationships among the cichorioid tribes are still unclear. The Lactuceae, Eremothamneae, Vernonieae and Liabeae may be one monophyletic group, and the Arctoteae, Carlineae, Echinopsideae and Cardueae another. The Mutisieae are a paraphyletic grade at the base of the family. Within the subfamily Asteroideae tribal interrelationships are also rather unclear. The Anthemideae and the Heliantheae sensu lato (including the Helenieae, Tageteae, Coreopsideae and all helenioid/helianthoid representatives sometimes placed in the Senecioneae) may be sister groups. The Heliantheae appear to be monophyletic and there is little support for the hypothesis that other tribes are derived from or have their sister group within the Heliantheae. The Astereae and the Eupatorieae may be sister groups, though a closer relationship between the Eupatorieae and the Heliantheae is possible. The Inuleae are a paraphyletic grade group at the base of the subfamily Asteroideae in the same way as the Mutiseae are a grade group at the base of the family.     

A review of the phylogeny and classification of the Asteraceae

The Asteraceae are commonly divided into two large subfamilies, the Cichorioideae (syn. Lactucoideae; Mutisieae, Cardueae, Lactuceae, Vernonieae, Liabeae, Arctoteae) and the Asteroideae (Inuleae, Astereae, Anthemideae, Senecioneae, Calenduleae, Heliantheae, Eupatorieae). Recent phylogenetic analyses based on morphological and chloroplast DNA data conclusively show that the Mutisieae-Barnadesiinae are the sister group to the rest of the family and that the Asteroideae tribes form a monophyletic group. The Vernonieae and Liabeae are sister tribes and the Eupatorieae are nested within a paraphyletic Heliantheae; otherwise tribal interrelationships are still largely uncertain. The Mutisieae-Barnadesiinae are excluded from the Mutisieae and elevated to the new subfamily Barnadesioideae. The two subfamilies Barnadesioideae and Asteroideae are monophyletic, whereas the status of the Cichorioideae remains uncertain. Analyses of chloroplast DNA data support the monophyly of the Cichorioideae; however, morphological data indicate that the subfamily is paraphyletic. Further studies are needed to test the monophyly of the Cichorioideae, as well as to further resolve tribal interrelationships in the two larger subfamilies.     

Terrestrial gastropods zoogeography in Southern Tamaulipas, México

Biogeography of Mexican terrestrial mollusks is poorly known, although many studies have described some of their biological aspects. This study aimed to contribute with new information on the distribution of terrestrial mollusks in this region of high altitudinal, topographic and climatic variations of Southern Tamaulipas State, México. For this, terrestrial gastropods were surveyed from December 1990 to November 2006. A total of 525 samples were obtained from 121 localities, characterized with different vegetation types. The primary zoogeographical feature was the presence of many endemic taxa, with 45 species or subspecies, representing the 43%, the highest value for Northeastern México. In addition, a total of 24 species (23%), were of Neotropical and Neartic distributions, and 15 species or subspecies (14%) exhibited Neotropical distributions. Furthermore, the family Spiraxidae showed the largest number of endemic species, with 17 species and two subspecies, and had the largest number of endemic species (27) for Northeastern México.     

The value of sampling anomalous taxa in phylogenetic studies: major clades of the Asteraceae revealed

The largest family of flowering plants Asteraceae (Compositae) is found to contain 12 major lineages rather than five as previously suggested. Five of these lineages heretofore had been circumscribed in tribe Mutisieae (Cichorioideae), a taxon shown by earlier molecular studies to be paraphyletic and to include some of the deepest divergences of the family. Combined analyses of 10 chloroplast DNA loci by different phylogenetic methods yielded highly congruent well-resolved trees with 95% of the branches receiving moderate to strong statistical support. Our strategy of sampling genera identified by morphological studies as anomalous, supported by broader character sampling than previous studies, resulted in identification of several novel clades. The generic compositions of subfamilies Carduoideae, Gochnatioideae, Hecastocleidoideae, Mutisioideae, Pertyoideae, Stifftioideae, and Wunderlichioideae are novel in Asteraceae systematics and the taxonomy of the family has been revised to reflect only monophyletic groups. Our results contradict earlier hypotheses that early divergences in the family took place on and spread from the Guayana Highlands (Pantepui Province of northern South America) and raise new hypotheses about how Asteraceae dispersed out of the continent of their origin. Several nodes of this new phylogeny illustrate the vast differential in success of sister lineages suggesting focal points for future study of species diversification. Our results also provide a backbone exemplar of Asteraceae for supertree construction.     

Echinoderms (Echinodermata) from the Mexican waters of the Gulf of Mexico

We present a systematic list of the echinoderms from Gulf of Mexico's Mexican waters based on specimens of the Colecci6n Nacional de Equinodermos, Instituto de Ciencias del Mar y Limnologia, Universidad Nacional Aut6noma de México and the National Museum of Natural History, Smithsonian Institution, Washington, D.C. This list reveals an important echinoderm biodiversity present in the Gulf of Mexico, where five of the six echinoderm classes are represented. A total of 209 echinoderm species is recorded, distributed in 129 genera, 63 families and 25 orders. 31 new records for the Gulf of Mexico are presented: Asteroidea (16), Ophiuroidea (nine), Echinoidea (one) and Holothuroidea (five).     

Niche shifts and range expansions along cordilleras drove diversification in a high‐elevation endemic plant genus in the tropical Andes

The tropical Andes represent one of the world's biodiversity hot spots, but the evolutionary drivers generating their striking species diversity still remain poorly understood. In the treeless high‐elevation Andean environments, Pleistocene glacial oscillations and niche differentiation are frequently hypothesized diversification mechanisms; however, sufficiently densely sampled population genetic data supporting this are still lacking. Here, we reconstruct the evolutionary history of Loricaria (Asteraceae), a plant genus endemic to the Andean treeless alpine zone, based on comprehensive population‐level sampling of 289 individuals from 67 populations across the entire distribution ranges of its northern Andean species. Partly incongruent AFLP and plastid DNA markers reveal that the distinct genetic structure was shaped by a complex interplay of biogeography (spread along and across the cordilleras), history (Pleistocene glacial oscillations) and local ecological conditions. While plastid variation documents an early split or colonization of the northern Andes by at least two lineages, one of which further diversified, a major split in the AFLP data correlate with altitudinal ecological differentiation. This suggests that niche shifts may be important drivers of Andean diversification not only in forest–alpine transitions, but also within the treeless alpine zone itself. The patterns of genetic differentiation at the intraspecific level reject the hypothesized separation in spatially isolated cordilleras and instead suggest extensive gene flow among populations from distinct mountain chains. Our study highlights that leveraging highly variable markers against extensive population‐level sampling is a promising approach to address mechanisms of rapid species diversifications.     

ITS secondary structure derived from comparative analysis: implications for sequence alignment and phylogeny of the Asteraceae

An RNA secondary structure model is presented for the nuclear ribosomal internal transcribed spacers (ITS) based on comparative analysis of 340 sequences from the angiosperm family Asteraceae. The model based on covariation analysis agrees with structural features proposed in previous studies using mainly thermodynamic criteria and provides evidence for additional structural motifs within ITS1 and ITS2. The minimum structure model suggests that at least 20% of ITS1 and 38% of ITS2 nucleotide positions are involved in base pairing to form helices. The sequence alignment enabled by conserved structural features provides a framework for broadscale molecular evolutionary studies and the first family-level phylogeny of the Asteraceae based on nuclear DNA data. The phylogeny based on ITS sequence data is very well resolved and shows considerable congruence with relationships among major lineages of the family suggested by chloroplast DNA studies, including a monophyletic subfamily Asteroideae and a paraphyletic subfamily Cichorioideae. Combined analyses of ndhF and ITS sequences provide additional resolution and support for relationships in the family.     

Paracreptotrema profundulusi n. sp. and P. blancoi Choudhury, Pérez-Ponce De León, Brooks, and Daverdin, 2006 (Trematoda: Allocreadiidae) from freshwater fishes of the genus Profundulus (Teleostei: Profundulidae) in southern México

Paracreptotrema profundulusi n. sp. (Trematoda: Allocreadiidae) is described from the intestine of the freshwater fishes Profundulus punctatus and P. balsanus (Teleostei: Profundulidae) from the Tehuantepec and the Atoyac-Verde River basins, in Oaxaca, México, in the western extreme of Central America. The new species is distinguished from Paracreptotrema blancoi Choudhury, Pérez-Ponce de León, Brooks, and Daverdin, 2006 , to which it is most similar, and from P. mendezi (Sogandares-Bernal, 1955) Choudhury, Pérez-Ponce de León, Brooks, and Daverdin, 2006 , by the caeca extending beyond the testes, vitelline follicles that invade the postesticular area, and uterus with transverse loops located mainly between the testes and the genital pore. Paracreptotrema blancoi was collected from the same host species and also from Profundulus oaxacae. Here, we provide data that show its broad distribution in several river basins of Neotropical southern México, including the Papagayo River basin, Guerrero, México, and the Atoyac-Verde and Tehuantepec river basins, and other rivers in Oaxaca, México. Freshwater fishes of the Profundulidae are endemic to Central America and host a helminth fauna that includes at least 4 species found only in these hosts.     

Flowering phenology of co-occurring Asteraceae: a matter of climate,ecological interactions,plant attributes or of evolutionary relationships among species?

We analyzed the flowering phenodynamics of 43 Asteraceae species co-occurring in natural populations of Chaco Serrano forests in central Argentina. We explored the potential influence of factors such as photoperiod and climate (variations in temperature, rainfall, and frost), animal-plant interactions (richness of floral visitors, frequency of visits), some plant attributes (plant growth form, seed dispersal mechanism), and evolutionary relationships among species on flowering phenodynamics. Cluster Analysis (CA) and Principal Component Analysis (PCA) were the multivariate statistical methods used to analyze emerging patterns associated with these co-occurring species. Null-model analyses were used to evaluate whether flowering times are aggregated, segregated, or random. Results showed that flowering phenology was significantly correlated with the seasonal variation in temperature, photoperiod, rainfall, and frost. The multivariate statistical methods separated all the species in three groups: 1) species with short flowering time, large plant floral display, high frequency of visits by a large number of species of floral visitors, anemochorous fruits, and shrubby growth form, with a tendency to a segregated flowering pattern; 2) species with long flowering time, small plant floral display, low frequency of visits by few insect species, anemochorous fruits, and herbaceous growth form; and 3) species with long flowering time, small plant floral display, intermediate values for frequency of visits and number of species of floral visitors, seed dispersal mechanisms other than anemochory, and herbaceous growth form. In addition, all but one species belonging to early-branching tribes (tribes phylogenetically close to the root of the Asteraceae tree) were grouped together and clustered in the same region of the two-dimensional PCA ordination. All species belonging to the late-branching tribes (Asteroideae subfamily tribes) included in group 1 were separated from the other Asteroideae species in the PCA. In conclusion, it seems that climatic factors restrict the phenological period of most species, and that plant attributes and taxonomic membership are strongly related to flowering phenodynamics in this group of Asteraceae studied.     

Dispersal and adaptive radiation of Bidens (Compositae) across the remote archipelagoes of Polynesia

The genus Bidens (Compositae) comprises c. 230 species distributed across five continents, with the 41 Polynesian species displaying the greatest ecomorphological variation in the group. However, the genus has had a long and complicated taxonomic history, and its phylogenetic and biogeographic history are poorly understood. To resolve the evolutionary history of the Polynesian Bidens, 152 individuals representing 91 species were included in this study, including 39 of the 41 described species from Polynesia. Four chloroplast and two nuclear DNA markers were utilized to estimate phylogenetic relationships, divergence times, and biogeographic history. Bidens was found to be polyphyletic within Coreopsis, consistent with previous assessments. The Polynesian radiation was resolved as monophyletic, with the initial dispersal into the Pacific possibly from South America to either the Hawaiian or Marquesas Islands. From the Marquesas, Bidens dispersed to the Society Islands, and ultimately to the Austral Islands. The initial diversification of the crown group in the Pacific is estimated to have occurred ~1.63 mya (0.74–2.72, 95% HPD), making Polynesian Bidens among the youngest and most rapid plant diversification events documented in the Pacific. Our findings suggest that relatively rare long‐distance dispersal and founder‐event speciation, coupled with subsequent loss of dispersal potential and within‐island speciation, can explain the repeated and explosive adaptive radiation of Bidens throughout the archipelagoes of Polynesia.     

Both host-plant phylogeny and chemistry have shaped the African seed-beetle radiation

For the last 40 years, many authors have attempted to characterize the main patterns of plant-insect evolutionary interactions and understand their causes. In the present work on African seed-beetles (Coleoptera: Bruchidae), we have performed a 10-year field work to sample seeds of more than 300 species of potential host-plants (from the family Fabaceae), to obtain bruchids by rearing. This seed sampling in the field was followed by the monitoring of adult emergences which gave us the opportunity to identify host-plant use accurately. Then, by using molecular phylogenetics (on a combined data set of four genes), we have investigated the relationships between host-plant preferences and insect phylogeny. Our objectives were to investigate the level of taxonomic conservatism in host-plant fidelity and host-plant chemistry. Our results indicate that phylogenetically related insects are associated with phylogenetically related host-plants but the phylogeny of the latter cannot alone explain the observed patterns. Major host shifts from Papilionoideae to Mimosoideae subfamilies have happened twice independently suggesting that feeding specialization on a given host-plant group is not always a dead end in seed-beetles. If host-plant taxonomy and chemistry in legumes generally provide consistent data, it appears that the nature of the seed secondary compounds may be the major factor driving the diversification of a large clade specializing on the subfamily Mimosoideae in which host-plant taxonomy is not consistent with chemical similarity.     

Novel classification and biogeography of Leptolejeunea (Lejeuneaceae,Marchantiophyta) with implications for the origin and evolution of the Asian evergreen broad-leaved forests

Although recent molecular phylogenetic analyses have greatly improved our understanding of the classification of the large liverwort family Lejeuneaceae, the frequent incongruencies between morphology-based taxonomy and molecular phylogeny have hindered our understanding of evolutionary diversification within the group. Here we focus on Leptolejeunea (Spruce) Steph., a pantropical epiphyllous genus in Lejeuneaceae with 40 species. Phylogenetic studies on the genus have been hampered by insufficient taxon sampling, leaving the deep phylogenetic relationships within this group unresolved. We present the most comprehensive phylogenetic analysis of the genus to date with sampling of over 80% of species, including the enigmatic Leptolejeunea spinistipula (Mizut.) X.L.He endemic to Borneo. Based on data from three molecular markers with representatives of Leptolejeunea and its allies, Leptolejeunea appeared to be monophyletic following the exclusion of L. spinistipula and its transfer to Soella R.L.Zhu, L.Shu, Qiong He & Y.M.Wei. A total-evidence approach was taken to resolve the backbone phylogeny of Leptolejeunea and a first infrageneric classification of Leptolejeunea, including a new subgenus and three new sections, is proposed based on integrated molecular and morphological evidence. Reconstruction of the evolutionary history showed a wide ancestral area of Leptolejeunea during the Paleogene that arose in mainland Asia, followed by an accelerated speciation rate. Across the biogeographical history of Leptolejeunea, long-distance dispersal had profound effects on population expansion. Our findings suggest that Australasia is a source of biodiversity of Asian evergreen broad-leaved forests that have been established since the Oligocene and rose after the early Miocene.     

Distorted perception of the spatial distribution of plant diversity through uneven collecting efforts: the example of Asteraceae in Australia

Aim Our aims were (1) to compare observed, estimated and predicted patterns of species richness using the Australian native Asteraceae as an example, (2) to identify candidates for hotspots of diversity for the study group, and (3) to examine the distortion of our perception of the spatial distribution of species richness through uneven or misdirected sampling efforts. Location Australia. Methods Based on data from Australia’s Virtual Herbarium, we calculated and visualized observed species richness, the Chao1 estimate of richness, the C index of collecting completeness, and an estimate of richness derived from environmental niche modelling for grid cells at a resolution of 1°. The 20 cells with the highest diversity values were used to define hotspots of diversity. Results Uneven collecting activity results in misleading diversity patterns for the family Asteraceae. While observed species richness is much higher in central Australia than in other parts of the arid interior, this is an artefact resulting from the area being a hotspot of collecting activity. The mountain ranges of south‐eastern Australia and Tasmania are candidates for unbiased hotspots of species richness. Main conclusions Vast areas of the Australian interior are insufficiently sampled on a local scale, although most of them can be expected to be relatively species poor. Some areas in the south‐east and south‐west of the continent remain undersampled relative to their high species richness. Observed species numbers, estimators and environmental niche‐modelling all have their unique advantages and disadvantages for the inference of patterns of diversity.