Chloroplast DNA restriction site variation in theVernonieae (Asteraceae), an initial appraisal of the relationship of New and Old World taxa and the monophyly ofVernonia

Chloroplast DNA restriction site variation was examined for 35 taxa in theVernonieae and four outgroup tribes, using 17 restriction enzymes mapped for ca. 900 restriction sites per species; 139 mutations were found to be phylogenetically informative. Phylogenetic trees were constructed using Wagner and weighted parsimony, and evaluated by bootstrap and decay analyses. Relationships of Old and New World taxa indicate complex geographical relationships; there was no clear geographic separation by hemisphere. The relationships between Old and New World Vernonias found here support prior morphological analyses. The sister group to all New and most Old World taxa was composed of a small group of Old World species including yellow-flowered, trinervate-leaved species previously postulated to be basal in the tribe. The majority of both New and Old World taxa are derived from a lineage beginning with the monotypic genusStokesia, an endemic of the southeastern United States. The genusVernonia was also found to be paraphyletic within both the New and Old World. Available data do not support either the separation ofVernonia or the tribeVernonieae into geographically distinct lineages. The pattern of relationships within theVernonieae for taxa from North America, Asia, Africa, Central and South America is most similar to that of several other groups of both plants and animals with a boreotropical origin, rather than an origin in Gondwanaland. Such a pattern of distribution suggests more ancient vicariant events than are routinely postulated for theAsteraceae.     

A global phylogeny of apple snails: Gondwanan origin, generic relationships, and the influence of outgroup choice (Caenogastropoda: Ampullariidae)

Apple snails (Ampullariidae) are a diverse family of pantropical freshwater snails and an important evolutionary link to the common ancestor of the largest group of living gastropods, the Caenogastropoda. A clear understanding of relationships within the Ampullariidae, and identification of their sister taxon, is therefore important for interpreting gastropod evolution in general. Unfortunately, the overall pattern has been clouded by confused systematics within the family and equivocal results regarding the family's sister group relationships. To clarify the relationships among ampullariid genera and to evaluate the influence of including or excluding possible sister taxa, we used data from five genes, three nuclear and two mitochondrial, from representatives of all nine extant ampullariid genera, and species of Viviparidae, Cyclophoridae, and Campanilidae, to reconstruct the phylogeny of apple snails, and determine their affinities to these possible sister groups. The results obtained indicate that the Old and New World ampullariids are reciprocally monophyletic with probable Gondwanan origins. All four Old World genera, Afropomus, Saulea, Pila, and Lanistes, were recovered as monophyletic, but only Asolene, Felipponea, and Pomella were monophyletic among the five New World genera, with Marisa paraphyletic and Pomacea polyphyletic. Estimates of divergence times among New World taxa suggest that diversification began shortly after the separation of Africa and South America and has probably been influenced by hydrogeological events over the last 90 Myr. The sister group of the Ampullariidae remains unresolved, but analyses omitting certain outgroup taxa suggest the need for dense taxonomic sampling to increase phylogenetic accuracy within the ingroup. The results obtained also indicate that defining the sister group of the Ampullariidae and clarifying relationships among basal caenogastropods will require increased taxon sampling within these four families, and synthesis of both morphological and molecular data. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98 , 61–76.     

Phylogeny, classification, and biogeography of the cycloteline Therevinae (Insecta: Diptera: Thereavidae)

Twenty-one members of the Laurasian group of Therevinae (Diptera: Therevidae) are compared using 65 adult morphological characters. Cladistic analysis using parsimony on the 17 ingroup and 4 outgroup taxa provides a well-supported hypothesis of relationships among taxa within the Gyclotelini, tribe nov. The Cyclotelini is a monophyletic assemblage of mostly New World genera, including Anolinga , gen. nov. , Breviperna Irwin, Coleiana , gen. nov. , Crebraseta , gen. nov. , Cyclotelus Walker, Mesonana , gen.nov. , and Ozodiceromyia Bigot. In addition, three Old World genera, Ammothereva Lyneborg, Bugulaverpa , gen. nov. , and Procyclotelus Nagatomi & Lyneborg, are included in the tribe. These ten genera are divided into two monophyletic genus-groups, the Brevipema-group and the Cyclotelus-group. Keys are provided for the genera of Cyclotelini. The tribe, the two informal genus-groups, and all genera are diagnosed; five new genera and six new species are proposed. The biogeographical histories of the genera are discussed in terms of their cladistic relationships using methods of cladistic biogeography. Two major vicariant events account for the current distribution of the tribe. The first relates to the Beringian land bridge connecting western North America and eastern Asia. Second, New World cyclotelines were profoundly affected by the Early Eocene breakup of the archipelagic bridge between North and South America, and the distributions support the hypotheses favouring the continental origin of the Greater Antilles.     

Salvia (Lamiaceae) is not monophyletic: implications for the systematics, radiation, and ecological specializations of Salvia and tribe Mentheae

Salvia, with over 900 species from both the Old and New World, is the largest genus in the Lamiaceae. Unlike most members of the subfamily Nepetoideae to which it belongs, only two stamens are expressed in Salvia. Although the structure of these stamens is remarkably variable across the genus, generally each stamen has an elongate connective and divergent anther thecae, which form a lever mechanism important in pollination. In a preliminary investigation of infrageneric relationships within Salvia, the monophyly of the genus and its relationship to other members of the tribe Mentheae were investigated using the chloroplast DNA regions rbcL and trnL-F. Significant conclusions drawn from the data include: Salvia is not monophyletic, Rosmarinus and Perovskia together are sister to an Old World clade of Salvia, the section Audibertia is sister to subgenus Calosphace or the monotypic Asian genus Dorystaechas, and the New World members of section Heterosphace are sister to section Salviastrum. Owing to the non-monophyly of Salvia, relationships at the next clearly monophyletic level, tribe Mentheae, were investigated.     

Phylogeny of South African Gnaphalieae (Asteraceae) based on two noncoding chloroplast sequences

The Gnaphalieae are a group of sunflowers that have their greatest diversity in South America, Southern Africa, and Australia. The objective of this study was to reconstruct a phylogeny of the South African Gnaphalieae using sequence data from two noncoding chloroplast DNA sequences, the trnL intron and trnL/trnF intergenic spacer. Included in this investigation are the genera of the Gnaphalieae from the African basal groups, members of the subtribes Cassiniinae, Gnaphaliinae, and Relhaniinae, and African representatives from the large Old World genus Helichrysum. Results indicate that two Gnaphaloid genera, Printzia and Callilepis, should be excluded from the Gnaphalieae. In most trees the Relhaniinae s.s. (sensu stricto) and some of the basal taxa comprise a clade that is sister to the remainder of the tribe Gnaphalieae. The Relhaniinae, which are restricted to Africa, are not a monophyletic group as presently circumscribed, nor are the South African members of Helichrysum, the Cassiniinae and Gnaphaliinae. There is general agreement between our molecular analysis and that of morphology, particularly in the terminal branches of the trees.     

Phylogenetic relationships of butterflies of the tribe Acraeini (Lepidoptera, Nymphalidae, Heliconiinae) and the evolution of host plant use

The tribe Acraeini (Nymphalidae, Heliconiinae) is believed to comprise between one and seven genera, with the greatest diversity in Africa. The genera Abananote, Altinote, and Actinote (s. str.) are distributed in the Neotropics, while the genera Acraea, Bematistes, Miyana, and Pardopsis have a Palaeotropical distribution. The monotypic Pardopsis use herbaceous plants of the family Violaceae, Acraea and Bematistes feed selectively on plants with cyanoglycosides belonging to many plant families, but preferentially to Passifloraceae, and all Neotropical species with a known life cycle feed on Asteraceae only. Here, a molecular phylogeny is proposed for the butterflies of the tribe Acraeini based on sequences of COI, EF-1alpha and wgl. Both Maximum Parsimony and Bayesian analyses showed that the tribe is monophyletic, once the genus Pardopsis is excluded, since it appears to be related to Argynnini. The existing genus Acraea is a paraphyletic group with regard to the South American genera, and the species of Acraea belonging to the group of "Old World Actinote" is the sister group of the Neotropical genera. The monophyly of South American clade is strongly supported, suggesting a single colonization event of South America. The New World Actinote (s. str.) is monophyletic, and sister to Abananote+Altinote (polyphyletic). Based on the present results it was possible to propose a scenario for the evolution in host plant use within Acraeini, mainly concerning the use of Asteraceae by the South American genera.     

Review of the systematics and phylogenetic relationships of the Sabethini (Diptera: Culicidae)

This paper reviews the historical treatment of the tribe Sabethini and genus-group taxa and examines the unusual life histories associated with the group. Although recognized by taxonomists as distinct, the taxonomic position of sabethines has been questioned and their rank within the family Culicidae unstable. In order to evaluate the current status of the classification of the tribe a cladistic analysis is performed. Thirty-seven taxa are selected from within the Sabethini and two outgroups were chosen from the tribe Aedini. Exemplars are selected from genus-group taxa world-wide and new and traditional character systems examined in larval, pupal and adult life stages. The results firmly establish the sabethines as a monophyletic group. However, the genera Runchomyia , Tripteroides and Wyeomyia are not demonstrably monophyletic. In addition, the data support the New World taxa as a monophyletic group to a paraphyletic assemblage of Old World taxa. The pattern displayed by the cladogram suggests the ability to vector arboviruses has arisen more than once in mosquitoes.     

The genus Artemisia (Asteraceae: Anthemideae) at a continental crossroads: molecular insights into migrations, disjunctions, and reticulations among Old and New World species from a Beringian perspective

Artemisia is the largest genus (ca. 350-500+ spp.) in the tribe Anthemideae and is composed of ecologically, morphologically, and chemically diverse species that are found primarily throughout the Northern Hemisphere. Two major centers of diversity for the genus are located in Eurasia and western North America, but phytogeographic links connecting these two regions are observed all across the North Pacific Rim and adjacent areas in the Arctic, including many islands and archipelagos. Previous phylogenetic studies have helped to clarify major lineages and identify likely sister relationships, but many questions remain unanswered regarding the relationships and migration history of New and Old World species. Here we investigate the phylogenetics of Artemisia within a biogeographic context centered in the Beringian Region and offer new hypotheses concerning species relationships, migration history, and the likely role of reticulate evolution in the genus. Our sampling included many new taxa and emphasized multiple accessions of widespread species, species from proposed refugia, and species with disjunct/vicariant distributions. The ITS phylogeny contained 173 accessions (94 new and 79 from GenBank) and indicated that Artemisia is paraphyletic by the exclusion of several small Asian genera and the North American genus Sphaeromeria. Following a survey of thirteen chloroplast loci, phylogenies based on two plastid markers (psbA-trnH and rpl32-trnL spacers) were constructed with a reduced data set, and though largely consistent with the ITS topology, revealed several cases of possible introgression among New World and Beringian species. Our analysis reveals that North American Artemisia species have multiple origins, and that western North America has served as a source for some colonizing elements in eastern Asia and South America.     

Melastomeae come full circle: biogeographic reconstruction and molecular clock dating

Rhexia, with 11 species in the Coastal Plain province of North America, is the only temperate zone endemic of the tropical eudicot family Melastomataceae. It is a member of the only pantropical tribe of that family, Melastomeae. Based on the chloroplast gene ndhF, we use a fossil-calibrated molecular clock to address the question of the geographic origin and age of Rhexia. Sequences from 37 species in 21 genera representing the tribe's geographical range were analyzed together with five outgroups. To obtain better clade support, another chloroplast region, the rpl16 intron, was added for 24 of the species. Parsimony analysis of the combined data and maximum-likelihood analysis of ndhF alone indicate that the deepest split is between Rhexia plus its sister group, a small Central American genus, and all other Melastomeae. Old World Melastomeae are monophyletic and nested within New World Melastomeae. Although likelihood-ratio tests of clock and nonclock substitution models for the full or moderately pruned datasets rejected the clock, these models yielded identical topologies (for 30 taxa) with few significantly different branch lengths as assessed by a Student's t-test. Age estimates obtained were 22 million years ago (Mya) for the divergence of Rhexia from its sister group, 12 Mya for the dispersal of Melastomeae from the New World to West Africa, and 1 Mya for the diversification of Melastoma in Southeast Asia. The only other genus of Melastomeae to have reached Southeast Asia from Africa or Madagascar is Osbeckia. The age and geographic distribution of fossils, which come from Miocene sites throughout Eurasia, suggest that Melastomeae once ranged from Eurasia across Beringia to North America from whence they reached South America and subsequently Africa and Southeast Asia. Climate deterioration led to their extinction in the Northern Hemisphere, with Rhexia possibly surviving in Coastal Plain refugia.     

Evolution, biogeography, and patterns of diversification in passerine birds

This paper summarizes and discusses the many new insights into passerine evolution gained from an increased general interest in avian evolution among biologists, and particularly from the extensive use of DNA sequence data in phylogenetic reconstruction. The sister group relationship between the New Zealand rifleman and all other passerines, indicates the importance of the former southern supercontinent Gondwana in the earliest evolution of this group. Following the break-up of Gondwana, the ancestors of other major passerine groups became isolated in Australia (oscines), South America (New World suboscines), and possibly, the then connected Kerguelen Plateau/India/Madagascar tectonic plates (Old World suboscines). The oscines underwent a significant radiation in the Australo-Papuan region and only a few oscine lineages have spread further than to the nearby Southeast Asia. A remarkable exception is the ancestor to the vast Passerida radiation, which now comprises 35% of all bird species. This group obviously benefitted greatly from the increased diversity in plant seed size and morphology during the Tertiary. The lyrebirds (and possibly scrub-birds) constitute the sister group to all other oscines, which renders "Corvida" ( sensu Sibley and Ahlquist 1990) paraphyletic. Sequence data suggests that Passerida, the other clade of oscines postulated based on the results of DNA–DNA hybridizations, is monophyletic, and that the rockfowl and rock-jumpers are the most basal members of this clade. The suboscines in the Old World (Eurylamides) and the New World (Tyrannides), respectively, are sister groups. A provisional, working classification of the passerines is presented based on the increased understanding of the major patterns of passerine evolution.     

Molecular phylogenetics of the giant genus Croton and tribe Crotoneae (Euphorbiaceae sensu stricto) using ITS and TRNL-TRNF DNA sequence data

Parsimony, likelihood, and Bayesian analyses of nuclear ITS and plastid trnL-F DNA sequence data are presented for the giant genus Croton (Euphorbiaceae s.s.) and related taxa. Sampling comprises 88 taxa, including 78 of the estimated 1223 species and 29 of the 40 sections previously recognized of Croton. It also includes the satellite genus Moacroton and genera formerly placed in tribe Crotoneae. Croton and all sampled segregate genera form a monophyletic group sister to Brasiliocroton, with the exception of Croton sect. Astraea, which is reinstated to the genus Astraea. A small clade including Moacroton, Croton alabamensis, and C. olivaceus is sister to all other Croton species sampled. The remaining Croton species fall into three major clades. One of these is entirely New World, corresponding to sections Cyclostigma, Cascarilla, and Velamea sensu Webster. The second is entirely Old World and is sister to a third, also entirely New World clade, which is composed of at least 13 of Webster's sections of Croton. This study establishes a phylogenetic framework for future studies in the hyper-diverse genus Croton, indicates a New World origin for the genus, and will soon be used to evaluate wood anatomical, cytological, and morphological data in the Crotoneae tribe.     

Phylogenetic relationships of Loxosceles and Sicarius spiders are consistent with Western Gondwanan vicariance

The modern geographic distribution of the spider family Sicariidae is consistent with an evolutionary origin on Western Gondwana. Both sicariid genera, Loxosceles and Sicarius are diverse in Africa and South/Central America. Loxosceles are also diverse in North America and the West Indies, and have species described from Mediterranean Europe and China. We tested vicariance hypotheses using molecular phylogenetics and molecular dating analyses of 28S, COI, 16S, and NADHI sequences. We recover reciprocal monophyly of African and South American Sicarius, paraphyletic Southern African Loxosceles and monophyletic New World Loxosceles within which an Old World species group that includes L. rufescens is derived. These patterns are consistent with a sicariid common ancestor on Western Gondwana. North American Loxosceles are monophyletic, sister to Caribbean taxa, and resolved in a larger clade with South American Loxosceles. With fossil data this pattern is consistent with colonization of North America via a land bridge predating the modern Isthmus of Panama.     

Systematics of the parasitic wasp genus Yelicones Cameron (Hymenoptera: Braconidae: Rogadinae) and revision of the genus from the New World

Species of the braconid wasp genus Yelicones Cameron from North, Central and South America are revised and the first phylogenetic analysis of the world Yelicones fauna is presented. The results are considered from a biogeographical perspective and the effect of including and excluding colour characters is investigated. One hundred and twenty‐four species from throughout the world are recognised. Eighty‐five species are from the New World, 63 of which are new. A fully illustrated key to New World species is provided. A total of 116 characters were scored, of which 86 were morphological and 30 were based on the wasps’ colour pattern. All analyses show a near perfect diversion between New and Old World species. However, analyses excluding and including colour produced completely opposite results in terms of whether New or Old World species were basal. We found that in our data matrix colour characters performed at least as well as morphological characters in terms of their ensemble retention index, making it difficult to decide which phylogenetic hypotheses is correct. However, consideration of venom apparatus features leads us to prefer the hypotheses placing the New World taxa basally.     

Phylogenetic relationships of North American Antirrhinum (Veronicaceae)

Species of the genus Antirrhinum (Veronicaceae) provide excellent opportunities for research on plant evolution given their extensive morphological and ecological diversity. These opportunities are enhanced by genetic and developmental data from the model organism Antirrhinum majus. The genus Antirrhinum includes 15 New World species in section Saerorhinum and 21 Old World species in sections Antirrhinum and Orontium. Phylogenetic analyses of sequences of the internal transcribed spacer region (ITS) of nuclear ribosomal DNA were conducted for 19 Antirrhinum species, including all species from the New World, and 13 related genera in the tribe Antirrhineae. These analyses confirm the monophyly of Antirrhinum given the inclusion of the small genus Mohavea and exclusion of A. cyathiferum. The New World species, all of which are tetraploid, form a clade that is weakly supported as sister to the Old World sect. Orontium. The Old World species in sect. Antirrhinum form a well-supported clade that is sister to the remainder of the genus. In addition, both molecular and morphological data are used in the most comprehensive effort to date focused on recovering the phylogenetic relationships among the extremely diverse species in section Saerorhinum.     

Mitochondrial and nuclear phylogenies of Cervidae (Mammalia, Ruminantia): Systematics, morphology, and biogeography

The family Cervidae includes 40 species of deer distributed throughout the northern hemisphere, as well as in South America and Southeast Asia. Here, we examine the phylogeny of this family by analyzing two mitochondrial protein-coding genes and two nuclear introns for 25 species of deer representing most of the taxonomic diversity of the family. Our results provide strong support for intergeneric relationships. To reconcile taxonomy and phylogeny, we propose a new classification where the family Cervidae is divided in two subfamilies and five tribes. The subfamily Cervinae is composed of two tribes: the tribe Cervini groups the genera Cervus, Axis, Dama, and Rucervus, with the Père David's deer (Elaphurus davidianus) included in the genus Cervus, and the swamp deer (Cervus duvauceli) placed in the genus Rucervus; the tribe Muntiacini contains Muntiacus and Elaphodus. The subfamily Capreolinae consists of the tribes Capreolini (Capreolus and Hydropotes), Alceini (Alces), and Odocoileini (Rangifer + American genera). Deer endemic to the New World fall in two biogeographic lineages: the first one groups Odocoileus and Mazama americana and is distributed in North, Central, and South America, whereas the second one is composed of South American species only and includes Mazama gouazoubira. This implies that the genus Mazama is not a valid taxon. Molecular dating suggests that the family originated and radiated in central Asia during the Late Miocene, and that Odocoileini dispersed to North America during the Miocene/Pliocene boundary, and underwent an adaptive radiation in South America after their Pliocene dispersal across the Isthmus of Panama. Our phylogenetic inferences show that the evolution of secondary sexual characters (antlers, tusk-like upper canines, and body size) has been strongly influenced by changes in habitat and behaviour.     

Phylogenetic relationships of mormyrid electric fishes (Mormyridae; Teleostei) inferred from cytochrome b sequences

The nasute termite genus Nasutitermes is widely distributed over all tropical regions. The phylogenetic relationships among 17 Nasutitermes species from the Pacific tropics were inferred from sequences of mitochondrial cytochrome oxidase II and 16S ribosomal RNA genes. Several methods of analysis yielded phylogenetic trees showing almost the same topology and in good agreement with reconstructions based on morphological or behavioral characters. Neotropical and Australian species came out as separate, apical clades. Asian species split between an apical branch, appearing as sister group to the neotropical clade, and basal taxa. New Guinean species were spread among several clades, suggesting a derivation from multiple origins. A well-supported clade includes the neotropical, Australian, and New Guinean species, with the southeast Asian N. takasagoensis and N. matangensis. It excludes the Asian species N. regularis, N. parvonasutus, and N. longinasus, which might deserve to be removed from Nasutitermes, as well as the long-legged Asian genera Hospitalitermes and Longipeditermes. A Gondwanan origin is proposed for the former clade, although an Old World origin of Nasutitermes followed by dispersal to Australia and South America cannot be excluded.     

A molecular phylogenetic analysis of the "true thrushes" (Aves: Turdinae)

The true thrushes (Passeriformes: Muscicapidae, subfamily Turdinae) are a speciose and widespread avian lineage presumed to be of Old World origin. Phylogenetic relationships within this assemblage were investigated using mitochondrial DNA (mtDNA) sequence data that included the cytochrome b and ND2 genes. Our ingroup sampling included 54 species representing 17 of 20 putative turdine genera. Phylogenetic trees derived via maximum parsimony and maximum likelihood were largely congruent. Most of the Turdine taxa sampled can be placed into one of six well supported clades. Our data indicate a polyphyletic Zoothera which can be divided into at least two (Afro-Asian and Austral-Asian) main clades. The genus Turdus, as presently recognized, is paraphyletic but forms a well supported clade with the addition of three mostly monotypic genera (Platycichla, Nesocichla, and Cichlherminia). We identify an exclusively New World clade that includes a monophyletic Catharus, Hylocichla, Cichlopsis, Entomodestes, Ridgwayia, and Ixoreus. Members of the morphologically and behaviorally distinct genera Sialia, Myadestes, and Neocossyphus unexpectedly form a basal clade. Using multiple outgroup choices, we show that this group is distantly related, but unequivocally the sister group to the remaining Turdines sampled. The Turdinae appear to be a relatively old songbird lineage, originating in the mid to late Miocene. If the Turdinae are indeed Old World in origin, our data indicate a minimum of three separate invasions of the New World.     

Piecing together the "new" Plantaginaceae

Scrophulariaceae is one of the families that has been divided extensively due to the results of DNA sequence studies. One of its segregates is a vastly enlarged Plantaginaceae. In a phylogenetic study of 47 members of Plantaginaceae and seven outgroups based on 3561 aligned characters from four DNA regions (the nuclear ribosomal ITS region and the plastid trnL-F, rps16 intron, and matK-trnK intron regions), the relationships within this clade were analyzed. The results from parsimony and Bayesian analyses support the removal of the Lindernieae from Gratioleae to a position outside Plantaginaceae. A group of mainly New World genera is paraphyletic with respect to a clade of Old World genera. Among the New World taxa, those offering oil as a pollinator reward cluster together. Ourisia is sister to this clade. Gratioleae consist of Gratiola, Otacanthus, Bacopa, Stemodia, Scoparia, and Mecardonia. Cheloneae plus Russelia and Tetranema together constitute the sister group to a clade predominantly composed of Old World taxa. Among the Old World clade, Ellisiophyllum and Lafuentea have been analyzed for the first time in a molecular phylogenetic analysis. The former genus is sister to Sibthorpia and the latter is surprisingly the sister to Antirrhineae.     

Phylogenetic analysis of the New World Ptininae (Coleoptera: Bostrichoidea)

A phylogenetic analysis of the New World Ptininae (Anobiidae) was conducted with representatives of nine of ten New World genera, several Old World genera and seven more of the ten subfamilies of Anobiidae. One hundred and two characters (forty‐three multistate) from thirty‐four taxa were used. The single cladogram shows Ptininae as monophyletic and the sister group of the remaining Anobiidae, supporting their placement as subfamilies of a monophyletic Bostrichidae. Genus Niptus Boieldieu is polyphyletic supporting recognition of Pseudeurostus Heyden and the creation of a new genus to encompass the remaining New World species of Niptus. Flightlessness has evolved a minimum of three times within Ptininae and myrmecophily has probably evolved three times within just the New World taxa. The classifications of Ptininae and the remaining Anobiidae are examined and the evolution of feeding habits, myrmecophily and wing loss are discussed.     

Nuclear ribosomal DNA and karyotypes indicate a NW African origin of South American Hypochaeris (Asteraceae, Cichorieae)

Hypochaeris has a disjunct distribution, with more than 15 species in the Mediterranean region, the Canary Islands, Europe, and Asia, and more than 40 species in South America. Previous studies have suggested that the New World taxa have evolved from ancestors similar to the central European H. maculata. Based on internal transcribed spacer (ITS) sequences and fluorescence in situ hybridization (FISH) with 5S and 18S-25S rDNA of the previously overlooked Hypochaeris angustifolia from Moyen Atlas, Morocco, we show that it is sister to the entire South American group. A biogeographic analysis supports the hypothesis of long-distance dispersal from NW Africa across the Atlantic Ocean for the origin of the South American taxa rather than migration from North America, through the Panamian land bridge, followed by subsequent extinction in North America. With the assumption of a molecular clock, the trans-Atlantic dispersal from NW Africa to South America is roughly estimated to have taken place during Pliocene or Pleistocene.