Phylogenetic relationships and evolution of Orbiniidae (Annelida, Polychaeta) based on molecular data

The phylogenetic relationships of orbiniid taxa were reconstructed based on sequence data of the mitochondrial 16S rRNA and nuclear 18S rRNA genes. Both genes were analysed separately and in combination using maximum likelihood, Bayesian inference and maximum parsimony. Regardless of the method used, a clade consisting of the investigated Orbiniidae, Methanoaricia dendrobranchiata and Questa was strongly supported by the 18S dataset. The analysis of the combined dataset suggests inclusion of M. dendrobranchiata within the Orbiniidae with close relationships to species of Orbinia and Phylo, rather than as a sister taxon to all other orbiniids. Evidence is given for the paraphyletic status of Leitoscoloplos , Naineris , Orbinia , Phylo and Scoloplos , which represent the most species-rich genera of the Orbiniidae. It is thus reasoned that the morphological characters presently used for genus diagnosis are not informative for cladistic analysis. No support is found for the hypothesis that taxa of the Protoariciinae represent juveniles of Orbiniinae. Instead, in the case of Protoaricia oerstedi , strong support for a progenetic origin is found.  © 2005 The Linnean Society of London, Zoological Journal of the Linnean Society , 2005, 144 , 59−73.     

Phylogenetic relationships in the subgenus Mus (genus Mus, family Muridae, subfamily Murinae): examining gene trees and species trees

Over eight kilobases (kb) of sequence from eight genes including two mitochondrial loci, Cyt b and 12S, and six nuclear loci, B2m , Zp3 , Tcp1, Sry, Smcx and Smcy , were used to investigate phylogenetic relationships among 11 taxa representing eight species within the rodent genus Mus . Particular attention was given to discerning relationships among species within the subgenus Mus including members of a Palearctic clade ( M. musculus , M. spicilegus , M. macedonicus and M. spretus ) and members of an Asian clade ( M. caroli , M. cookii and M. cervicolor ), as previous studies using different datasets have produced different topologies for taxa within these two groups. While parsimony analyses of the combined eight-gene dataset yielded a single, fully resolved tree, support values were lower for nodes resolving relationships within the Palearctic and Asian clades than they were elsewhere in the tree. In addition, a maximum likelihood analysis of the same eight-gene dataset yielded different topologies for both the Palearctic and the Asian clades. Both observations are indicative of clade instability. The nature of this instability was explored through a comparison with our previous study in which we included the two mitochondrial loci and only four of the six nuclear genes, and through an analysis of partitioned data, specifically mitochondrial vs. nuclear genes. This study underscores the importance of considering among-site rate variation in phylogeny reconstruction. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 84 , 653–662.     

Molecular systematics of North American phoxinin genera (Actinopterygii: Cyprinidae) inferred from mitochondrial 12S and 16S ribosomal RNA sequences

The cyprinid fish fauna of North America is relatively large, with approximately 300 species, and all but one of these are considered phoxinins. The phylogenetic relationships of the North American phoxinins continue to pose difficulties for systematists. Results of morphological analyses are not consistent owing to differences interpreting and coding characters. Herein, we present phylogenetic analyses of mitochondrial 12S and 16S ribosomal RNA sequence data for representatives of nearly all genera of North American phoxinins. The data were analysed using parsimony, weighted parsimony, maximum likelihood and bayesian analyses. Results from weighted parsimony, likelihood and the bayesian analysis are largely consistent as they all account for differing substitution rates between transitions and transversions. Several major clades within the fauna can be recognized and are strongly supported by all analyses. These include the western clade, creek chub–plagopterin clade and the open posterior myodome clade. The shiner clade is nested in the open posterior myodome clade and is the most species-rich clade of North American phoxinins. Relationships within this clade were not well resolved by our analyses. This may reflect the inability of the mitochondrial RNA genes to resolve recent speciation events or taxon sampling within the shiner clade.  © 2003 The Linnean Society of London, Zoological Journal of the Linnean Society , 2003, 139 , 63–80.     

Sophora sect. Edwardsia (Fabaceae): further evidence from nrDNA sequence data of a recent and rapid radiation around the Southern Oceans

Phylogenetic relationships are inferred from nuclear ribosomal internal transcribed spacer sequences for species belonging to Sophora sect. Edwardsia from South America, New Zealand, Lord Howe Island, Hawai'i, La Réunion, Easter Island, and Raivavae Island (French Polynesia). Results support the monophyly of sect. Edwardsia , but relationships among the species from this section are poorly resolved due to most species having identical sequences. The origin of Sophora sect. Edwardsia is discussed, as competing hypotheses have proposed the group originated in South America from a North American ancestor, or in the north-west Pacific. We suggest sect. Edwardsia may have arisen in the north-west Pacific from a Eurasian ancestor.  © The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 140 , 435–441.     

Molecular phylogeny and zoogeography of the freshwater crayfish genus Cherax Erichson (Decapoda: Parastacidae) in Australia

The evolutionary history and biogeography of freshwater-dependent taxa in Australia is of intrinsic interest given the present-day aridity of this continent. Cherax is the most widespread and one of the most species-rich of Australia's nine freshwater crayfish genera. The phylogenetic relationships amongst 19 of the 23 Australian Cherax were established from mitochondrial DNA sequences representing the 12S rRNA and 16S rRNA gene regions. The relationships among species support an initial east–west separation, followed by a north–south divergence in eastern Australia. Molecular clock estimations suggest that these divergences date back to the Miocene. The phylogenetic relationships support endemic speciation within geographical regions and indicate that long-distance dispersal has not led to recent speciation as previously hypothesized. This new evolutionary scenario is consistent with the climatic history of Australia and the evolutionary history of other similarly distributed freshwater-dependent organisms in Australia.  © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 81 , 553–563.     

A phylogenetic study of chthamaloids (Cirripedia; Thorcica; Chthamaloidae) based on 16S rDNA and COI sequence analysis

The sequences of gene fragments encoding cytochrome  c oxidase subunit I (COI) and 16S rDNA were obtained and used to construct phylograms of eight taxa of chthamaloid barnacles using the scalpelloid Calantica as an out-group. The phylograms support the basal position of Catomerus within the chthamaloids . Analysis of 16S rDNA shows that Octomeris and the four-plated barnacle Chamaesipho are located on the same clade, while Chthamalus , Euraphia and Tetrachthamalus are located on a second clade, indicating that reduction in the number of shell plates occurred twice in the evolution of the chthamaloids. The topology of phylograms based on COI sequences is poorly resolved: 93% of third position nucleotides in this fragment are polymorphic while the amino acid sequences are strictly conserved. We assume that in the chthamaloids, at least at the generic level, polymorphism in the COI gene is saturated beyond phylogenetic information and cannot resolve the phylogenetic relationships within this superfamily.  © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 83 , 39–45.     

Phylogenetic relationships of thorny catfishes (Siluriformes: Doradidae) inferred from molecular and morphological data

Doradidae is a putatively monophyletic group of South American freshwater catfishes containing 30 extant genera and 72 valid species. Only one study to date has attempted to estimate phylogenetic relationships among doradids. This morphological analysis partitioned species into two basal genera ( Wertheimeria and Francisodoras ) and a crown group of three subfamilies (Platydoradinae, Astrodoradinae and Doradinae) whose relationships were unresolved. No subsequent work has been done to resolve the subfamilial trichotomy or to assess whether postulated intergeneric relationships are accurate. We address this problem with complete sequences (2.5 kilobases, kb) of mitochondrial 12S and 16S rRNA genes and partial (1.3 kb) sequences of the nuclear elongation factor-1 alpha (EF1α) gene from representatives of 23 doradid genera (43 species) and 13 outgroups from additional siluriform families. Phylogenetic analysis of these data yields strong support for the monophyly of Doradidae and Astrodoradinae (as well as other relationships), but otherwise shows significant conflict with morphological results. A partial re-examination of published morphological data indicates that many characters may have been incorrectly polarized and many taxa have incorrect state assignments. Our results provide a framework for ongoing efforts to describe the species-level diversity of this poorly understood neotropical family.  © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society , 2004, 140 , 551–575.     

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.     

Systematics of African lowland rainforest Praomys (Rodentia, Muridae) based on molecular and craniometrical data

Representatives of the genus Praomys occur throughout the African intertropical zone. It is unclear how many species this genus contains, nor do we know the exact distribution ranges and phylogenetic relationships of these taxa. Using molecular (16S rRNA gene sequencing) and morphological (multivariate craniometry) analyses we clarify the taxonomy and phylogenetic relationships among the Praomys occurring in Africa's lowland tropical rainforests. We studied most species known from this area, based on specimens collected in seven countries (Guinea, Ivory Coast, Cameroon, Central African Republic, Gabon, Congo Republic and Democratic Republic of Congo). In our study, Praomys appears to be monophyletic. Our results identify two species complexes: the jacksoni complex includes at least two species ( P. jacksoni and P. mutoni ) and the tullbergi complex contains at least four species ( P. tullbergi , P. rostratus , P. misonnei , P. petteri ). Although the 16S rRNA gene appears insufficient to resolve the phylogenetic relationships among all the members of the tullbergi species complex, it is suitable for the identification of most of the studied species, and its use has allowed us to redefine the geographical limits of several species.  © 2005 The Linnean Society of London, Zoological Journal of the Linnean Society , 2005, 145 , 539–553.     

The phylogenetic position of toadfishes (order Batrachoidiformes) in the higher ray-finned fish as inferred from partitioned Bayesian analysis of 102 whole mitochondrial genome sequences

In a previous study based on 100 whole mitochondrial genome (mitogenome) sequences, we sought to provide a new perspective on the ordinal relationships of higher ray-finned fish (Actinopterygii). The study left unexplored the phylogenetic position of toadfishes (order Batrachoidiformes), as data were unavailable owing to technical difficulties. In the present study, we successfully determined mitogenomic sequences for two toadfish species ( Batrachomoeus trispinosus and Porichthys myriaster ) and found that the difficulties resulted from unusual gene arrangements and associated repetitive non-coding sequences. Unambiguously aligned, concatenated mitogenomic sequences (13 461 bp) from 102 higher actinopterygians (excluding the ND6 gene and control region) were divided into five partitions (1st, 2nd and 3rd codon positions of the protein-coding genes, tRNA genes and rRNA genes) and partitioned Bayesian analyses were conducted. The resultant phylogenies strongly suggest that the toadfishes are not members of relatively primitive higher actinopterygians (Paracanthopterygii), but belong to a crown group of actinopterygians (Percomorpha), as was demonstrated for ophidiiform eels (Ophidiiformes) and anglerfishes (Lophiiformes) in the previous study. We propose revised limits of major unranked categories for higher actinopterygians and a new name (Berycomorpha) for a clade comprising two reciprocally paraphyletic orders (Beryciformes and Stephanoberyciformes) based on the present mitogenomic phylogenies.  © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 85 , 289–306.     

Systematics and biogeography of the New World species of Trichadenotecnum Enderlein (Insecta: Psocodea: 'Psocoptera': Psocidae)

The taxonomy of the New World species of the genus Trichadenotecnum is revised. A total of 44 species, including 29 new species, were treated. These species are classified into 12 monophyletic species groups, eight of them newly proposed here. Two species previously assigned to Trichadenotecnum , T. pichincha New & Thornton and T. sylvaticum Turner, are recognized as not belonging to this genus. Phylogenetic relationships among 16 previously and presently proposed species groups are estimated based on a data matrix of 58 morphological characters. Trees from these analyses support monophyly of Trichadenotecnum and the proposed species groups. The New World species were divided into three major clades. Based on the phylogenetic hypothesis and distributional pattern of the species groups, the biogeographical history of the New World Trichadenotecnum is discussed.  © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society , 2008, 153 , 651–723.     

Phylogenetic patterns of diversification in a clade of Neotropical frogs (Anura: Aromobatidae: Mannophryne)

We used partial sequences of mitochondrial 16S and cytochrome oxidase I genes to perform a phylogenetic study of collared frogs (Anura: Aromobatidae: Mannophryne ), a genus endemic to Venezuela and the islands of Trinidad and Tobago. We analysed 1.2 kb from 13 of the 15 described species of Mannophryne . Maximum parsimony, maximum likelihood and Bayesian analyses support the monophyly of Mannophryne . Mannophryne consists of three deeply differentiated clades that split from each other in a relatively short period of time. The diversification of Mannophryne occurred well before the glacial-interglacial periods of the Quaternary. Our data support the taxonomic validity of M. olmonae , a species endemic to Tobago Island. Mannophryne olmonae is more closely related to the continental species Mannophryne riveroi than to the Trinidad island endemic Mannophryne trinitatis . As in most tropical clades of frogs, molecular evidence indicates that species richness in Mannophryne is largely underestimated and, consequently, current priorities for conservation are inadequate.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 97 , 185–199.     

A revision and phylogenetic analysis of Stapeliopsis (Apocynaceae)

A survey of morphological characters is carried out for Stapeliopsis . The information obtained from this is combined with molecular data from the plastid trn L-F DNA region and ITS1 of the nuclear encoded 18S−26S rRNA cistron, to obtain a hypothesis of the evolutionary relationships among the species. It is shown that Stapeliopsis is monophyletic in a combined molecular and morphological analysis. Stapeliopsis is sister to a clade containing Huernia , Orbea and Tromotriche . The species of Stapeliopsis group into two clades. One contains S. khamiesbergensis , S. neronis and S. urniflora , and this is highly supported. The remaining species fall into an unsupported clade in which S. exasperata is sister to the others. The genera Hermanschwartzia Plowes and Neopectinaria Plowes are rejected. It is shown that a synapomorphy for Stapeliopsis is the laterally flattened inner corona-lobes, which touch the anthers only at their bases. Eight species of Stapeliopsis are recognized, with no subgeneric divisions.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 148 , 125–155.     

A new species of Saussurea (Asteraceae) from Tibet and its systematic position based on ITS sequence analysis

A new species of Saussurea , S. erecta S. W. Liu, J. T. Pan & J. Q. Liu sp. nov. , is described from Tibet. It resembles S. kingii but may be distinguished by having distinct stems and glabrous achenes. Saussurea kingii was placed in sect. Pseudoeriocoryne of subgen. Eriocoryne ; this section was circumscribed by acaulescence and an inflorescence with congested capitula surrounded by a rosette of leaves. The discovery of S. erecta with distinct stems, cauline leaves and corymbose capitula blurred the delimitation of sect. Pseudoeriocoryne and suggested that the section may be polyphyletic. Both the close relationship and the significant difference between S. erecta and S. kingii were confirmed by analyses of nrDNA ITS sequences. The resulting phylogenies based on ITS data further suggest that Saussurea sect. Pseudoeriocoryne , as traditionally defined, does not constitute a monophyletic group. The rapid radiation and speciation of Saussurea in the Qinghai-Tibetan Plateau, as inferred from ITS phylogeny, are discussed.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 147 , 349–356.     

Evolutionary relationships among the Pulmonate land snails and slugs (Pulmonata, Stylommatophora)

We have incorporated an additional 56 species of land snails and slugs in our ribosomal (r) RNA molecular phylogeny. The new taxa include representatives of several important groups. The molecular tree now includes 160 species of stylommatophoran land snails and slugs in 144 genera in 61 families. In the rDNA tree, the Stylommatophora are principally divided into an 'achatinoid' and a 'non-achatinoid' clade. Within these clades, several major land snail groups, including the Orthurethra, Elasmognatha, Limacoidea, and Helicoidea, are supported. Overall, the rDNA molecular phylogeny has remained stable following the incorporation of the additional taxa, with these additions having little impact on the major evolutionary patterns in the tree. Taxonomic coverage of the Orthurethra, Orthalicidae, Camaenidae, and Bradybaenidae is increased significantly. The camaenids and bradybaenids form a complex, and both appear to be paraphyletic. Several families of uncertain affinity, such as the Sagdidae and Thyrophorellidae, are included for the first time. The Sagdidae are shown to belong to the Helicoidea, and the Thyrophorellidae to the Achatinoidea.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 87 , 593–610.     

Phylogenetic relationships of the north-eastern Atlantic and Mediterranean blenniids

The phylogenetic relationships of 27 north-eastern Atlantic and Mediterranean blennioids are analysed based on a total of 1001 bp from a combined fragment of the 12S and 16S mitochondrial rDNA. The most relevant results with implications in current blenniid taxonomy are: (1) Lipophrys pholis and Lipophrys (=  Paralipophrys ) trigloides are included in a well-supported clade that by the rule of precedence must be named Lipophrys ; (2) the sister species of this clade are not the remaining species of the genus Lipophrys but instead a monotypic genus comprising Coryphoblennius galerita ; (3) the smaller species of Lipophrys were recovered in another well-supported and independent clade, which we propose to be recognized as Microlipophrys ; (4) although some authors included the genera Salaria and Lipophrys in a single group we have never recovered such a relationship. Instead, Salaria is more closely related to the genera Scartella and Parablennius ; (5) the genus Parablennius , which was never recovered as a monophyletic clade, is very diverse and may include several distinct lineages; (6) the relative position of Aidablennius sphynx casts some doubts on the currently recognized relationships between the different blenniid tribes. Meristic, morphological, behavioural and ecological characters support our results and are also discussed. The possible roles of the tropical West African coast and the Mediterranean in the diversification of blenniids are discussed.  © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 86 , 283–295.     

Phylogeny and biogeographical history of Trogoniformes, a pantropical bird order

With highly conserved morphology throughout the family, a tropical distribution, and no close living relatives, the trogons (Aves: Trogonidae) pose a difficult problem for systematists. Disjunct tropical distributions are often attributed to Gondwanan vicariance, but the fossil record for trogons is mostly from the Tertiary of Europe. This study examined support for the basal relationships among trogons using a combination of nuclear (RAG-1) and mitochondrial (ND2) DNA sequence data. Although some nodes could not be resolved with significant support, there is strong support for the basal position of three New World genera ( Pharomachrus , Euptilotis , and Priotelus ). This phylogenetic hypothesis differs markedly from previous studies of trogon relationships and taxonomic treatments. Biogeographically, it implies an origin and early vicariance events for the crown clade in the New World. Molecular divergence estimates place all of the basal nodes of the trogon phylogeny in the Oligocene, precluding a Gondwanan origin for modern trogons.  © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 84 , 725–738.     

Phylogenetic relationships among Rhacophorinae (Rhacophoridae, Anura, Amphibia), with an emphasis on the Chinese species

The partial nucleotide sequence of mitochondrial 12S and 16S rRNA genes was determined for 23 Chinese species of Rhacophoridae (Amphibia: Anura), representing four of the eight recognized genera. Using Buergeriinae as the outgroup, phylogenetic analyses (maximum parsimony, maximum likelihood, and Bayesian inference) were performed in combination with already published mitochondrial 12S and 16S sequences of Rhacophorinae frogs. In all cases, Philautus romeri Smith, 1953 is recovered as the sister taxon to all other Rhacophorinae, although the support values are weak. Chirixalus doriae Boulenger, 1893 is closer to Chiromantis [ Chiromantis rufescens (Günther, 1868) and Chiromantis xerampelina Peters, 1854] than to Chirixalus vittatus (Boulenger, 1887). The clade { Philautus odontotarsus Ye & Fei, 1993, [ Philautus idiootocus (Kuramoto & Wang, 1987), Kurixalus eiffingeri (Boettger, 1895)]} is recovered with strong support. The monophyly of Theloderma and Rhacophorus rhodopus Liu & Hu, 1959 is not supported. It is suggested that Philautus albopunctatus Liu & Hu, 1962 should be placed into the synonymy of Theloderma asperum (Boulenger, 1886), and that Philautus rhododiscus Liu & Hu, 1962 should be assigned to Theloderma , so as to correct the paraphyly. Additionally, the monophyly of ' Aquixalus ' is not supported, and this requires further examination. Results also indicate that the Rhacophorus leucomystax (Gravenhorst, 1829)/ Rhacophorus megacephalus (Hallowell, 1861) complex needs further revision. Studies employing broader sampling and more molecular markers will be needed to resolve the deep relationships within the subfamily Rhacophorinae.  © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 153 , 733–749.     

Natural hybridization does not dissolve species boundaries in commercially important sea cucumbers

The study of species boundaries in areas of sympatry provides important insight into speciation processes. We investigated whether (i) two sympatric holothurians, Holothuria scabra and H. s. var. versicolor constituted species, and (ii) specimens of intermediate phenotype hybrids. Results from allozyme and 16S mtDNA sequence analyses indicated these two sea cucumbers to be distinct but young biological and phylogenetic species. Several private allozyme alleles existed and a Bayesian analysis grouped varieties into separate clusters. MtDNA sequences hardly varied within each taxon, and nine single bp changes were diagnostic between these two taxa. Allozyme allele frequencies in individuals of intermediate phenotype were intermediate to those of H. scabra and H. s.  var.  versicolor , most private alleles were present and heterozygote frequencies were higher than in either species. Ancestry coefficients modelled for these individuals were close to 0.5, indicating that the two taxa contributed equally to their genome. MtDNA sequences were identical to those of either species. We conclude that individuals of intermediate phenotype represent F1 hybrids. The presence of hybrids demonstrates that the opportunity for introgression exists, but is not realized, as backcrossing and introgression were not supported by the data. Thus, the genetic integrity of either holothurian species remains intact through an unknown postzygotic mechanism, possibly hybrid sterility.  © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 85 , 261–270.     

Phylogeny of South American Bufo (Anura: Bufonidae) inferred from combined evidence

Despite the considerable research that has focused on the evolutionary relationships and biogeography of the genus Bufo, an evolutionary synthesis of the entire group has not yet emerged. In the present study, almost 4 kb of DNA sequence data from mitochondrial (12S, tRNA^Val, and 16S) and nuclear (POMC; Rag-1) genes, and 83 characters from morphology were analysed to infer a phylogeny of South American toads. Phylogenies were reconstructed with parsimony and maximum likelihood and Bayesian model-based methods. The results of the analysis of morphological data support the hypothesis that within Bufo , some skull characters (e.g. frontoparietal width), correlated with the amount of cranial ossification, are prone to homoplasy. Unique and unreversed morphological synapomorphies are presented that can be used to diagnose recognized species groups of South American toads. The results of all phylogenetic analyses support the monophyly of most species groups of South American Bufo . In most DNA-only and combined analyses, the South American (minus the B. guttatus and part of the ' B. spinulosus ' groups), North American, Central American, and African lineages form generally well-supported clades: ((((((((South America) (North America + Central America)) Eurasia) Africa) Eurasia) South America) West Indies) South America). This result confirms and extends prior studies recovering South American Bufo as polyphyletic. The biogeographical results indicate that: (1) The origin of Bufo predates the fragmentation of Gondwana; (2) Central and North American species compose the sister group to a large, 'derived' clade of South American Bufo ; and (3) Eurasian species form the sister group to the New World clade.  © 2006 The Linnean Society of London, Zoological Journal of the Linnean Society , 2006, 146 , 407–452.