Comparative molecular phylogeny and evolution of sex chromosome DNA sequences in the family Canidae (Mammalia: Carnivora)

To investigate the molecular phylogeny and evolution of the family Canidae, nucleotide sequences of the zinc-finger-protein gene on the Y chromosome (ZFY, 924-1146 bp) and its homologous gene on the X chromosome (ZFX, 834-839 bp) for twelve canid species were determined. The phylogenetic relationships among species reconstructed by the paternal ZFY sequences closely agreed with those by mtDNA and autosomal DNA trees in previous reports, and strongly supported the phylogenetic affinity between the wolf-like canids clade and the South American canids clade. However, the branching order of some species differed between phylogenies of ZFY and ZFX genes: Cuon alpinus and Canis mesomelas were included in the wolf-like canid clades in the ZFY tree, whereas both species were clustered in a group of Chrysocyon brachyurus and Speothos venaticus in the ZFX tree. The topology difference between ZFY and ZFX trees may have resulted from the two-times higher substitution rate of the former than the latter, which was clarified in the present study. In addition, two types of transposable element sequence (SINE-I and SINE-II) were found to occur in the ZFY final intron of the twelve canid species examined. Because the SINE-I sequences were shared by all the species, they may have been inserted into the ZFY of the common ancestor before species radiation in Canidae. By contract, SINE-II found in only Canis aureus could have been inserted into ZFY independently after the speciation. The molecular diversity of SINE sequences of Canidae reflects evolutionary history of the species radiation.     

Ecogeographical Variation in Skull Shape of South-American Canids: Abiotic or Biotic Processes?

Species morphological changes can be mutually influenced by environmental or biotic factors, such as competition. South American canids represent a quite recent radiation of taxa that evolved forms very disparate in phenotype, ecology and behaviour. Today, in the central part of South America there is one dominant large species (the maned wolf, Chrysocyon brachyurus) that directly influence sympatric smaller taxa via interspecific killing. Further south, three species of similar sized foxes (Lycalopex spp.) share the same habitats. Such unique combination of taxa and geographic distribution makes South American dogs an ideal group to test for the simultaneous impact of climate and competition on phenotypic variation. Using geometric morphometrics, we quantified skull size and shape of 431 specimens belonging to the eight extant South American canid species: Atelocynus microtis, Cerdocyon thous, Ch. brachyurus, Lycalopex culpaeus, L. griseus, L. gymnocercus, L. vetulus and Speothos venaticus. South American canids are significantly different in both skull size and shape. The hypercarnivorous bush dog is mostly distinct in shape from all the other taxa while a degree of overlap in shape—but not size—occurs between species of the genus Lycalopex. Both climate and competition impacts interspecific morphological variation. We identified climatic adaptations as the main driving force of diversification for the South American canids. Competition has a lower degree of impact on their skull morphology although it might have played a role in the past, when canid community was richer in morphotypes.     

History of canids in Chile and impacts on prey adaptations

Artiodactyl prey species of Chile, especially guanacos (Lama guanicoe), are reported to be very susceptible to predation by pack‐hunting feral dogs. It has been previously suggested that guanacos and endemic South American deer may have evolved in the absence of pack‐hunting cursorial predators. However, the paleoecology of canid presence in southern South America and Chile is unclear. Here, we review the literature on South American and Chilean canids, their distributions, ecologies, and hunting behavior. We consider both wild and domestic canids, including Canis familiaris breeds. We establish two known antipredator defense behaviors of guanacos: predator inspection of ambush predators, for example, Puma concolor, and rushing at and kicking smaller cursorial predators, for example, Lycalopex culpaeus. We propose that since the late Pleistocene extinction of hypercarnivorous group‐hunting canids east of the Andes, there were no native species creating group‐hunting predation pressures on guanacos. Endemic deer of Chile may have never experienced group‐hunting selection pressure from native predators. Even hunting dogs (or other canids) used by indigenous groups in the far north and extreme south of Chile (and presumably the center as well) appear to have been used primarily within ambush hunting strategies. This may account for the susceptibility of guanacos and other prey species to feral dog attacks. We detail seven separate hypotheses that require further investigation in order to assess how best to respond to the threat posed by feral dogs to the conservation of native deer and camelids in Chile and other parts of South America.     

Phylogeny of the large extinct South American Canids (Mammalia,Carnivora, Canidae) using a “total evidence” approach

South America currently possesses a high diversity of canids, comprising mainly small to medium‐sized omnivorous species, but in the Pleistocene there were large hypercarnivorous taxa that were assigned to Protocyon spp., Theriodictis spp., Canis gezi, Canis nehringi and Canis dirus. These fossils have never been included in phylogenies based on quantitative cladistics, but hand‐constructed cladograms published in the 1980s included some of them in the South American canine clade and others in the Canis clade. In this work, the phylogenetic position of the large extinct South American canids was studied using a large sample of living and extinct canids, as well as different sources of characters (e.g. DNA and 133 osteological characters). The phylogenetic analysis corroborates the inclusion of Theriodictis and Protocyon in the “South American clade”, where C. gezi is also included. In addition, the position of C. dirus as a highly derived Canis species is confirmed. The simultaneous analysis supports hypercarnivory having arisen at least three times in Caninae and once in the “South American clade”. The combination of the phylogenetic analyses, the fossil record and divergence dates estimated in previous works suggests that at least three or four independent lineages of the “South American clade” invaded South America after the establishment of the Panama bridge around 3 million years ago, plus other events corresponding to the immigration of Urocyon and Canis dirus.
© The Willi Hennig Society 2009.     

Molecular systematics of the Canidae

Despite numerous systematic studies, the relationships among many species within the dog family, Canidae, remain unresolved. Two problems of broad evolutionary significance are the origins of the taxonomically rich canidae fauna of South America and the development in three species of the trenchant heel, a unique meat-cutting blade on the lower first molar. The first problem is of interest because the fossil record provides little evidence for the origins of divergent South American species such as the maned wolf and the bush dog. The second issue is problematic because the trenchant heel, although complex in form, may have evolved independently to assist in the processing of meat. We attempted to resolve these two issues and five other specific taxonomic controversies by phylogenetic analysis of 2,001 base pairs of mitochondrial DNA (mtDNA) sequence data from 23 canidae species. The mtDNA tree topology, coupled with data from the fossil record, and estimates of rates of DNA sequence divergence suggest at least three and possibly four North American invasions of South America. This result implies that an important chapter in the evolution of modern canids remains to be discovered in the fossil record and that the South American canidae endemism is as much the result of extinction outside of South America as it is due to speciation within South America. The origin of the trenchant heel is not well resolved by our data, although the maximum parsimony tree is weakly consistent with a single origin followed by multiple losses of the character in several extant species. A combined analysis of the mtDNA data and published morphological data provides unexpected support for a monophyletic South American canidae clade. However, the homogeneity partition tests indicate significant heterogeneity between the two data sets.     

Sigmodontine rodents diversified in South America prior to the complete rise of the Panamanian Isthmus

The extant distribution of sigmodontine rodents encompasses most of the New World, and the majority of the species in this subfamily inhabit South America. Nevertheless, the basal lineages of the Sigmodontinae are distributed in North and Central America, and the fossil record indicates a North American origin. This evidence has produced contentious theories concerning the evolution of these rodents. The dispute usually stems from a disagreement about the way in which sigmodontines reached South America, which was an isolated landmass during most of the Cenozoic. Fundamentally, the debate is associated with the role of Panamanian Isthmus formation and the Great American Biotic Interchange (GABI) in the diversification of the clade. An early hypothesis implies that sigmodontines arrived in South America before the complete rise of the Panamanian Isthmus, whereas a late hypothesis directly correlates the diversification of the lineage with this event. To address this question, we have sequenced nuclear and mitochondrial sequences, as well as the first Sigmodontinae mitochondrial genomes (Akodon montensis and Wiedomys cerradensis) and performed a Bayesian dating analysis. Our results showed that the most recent common ancestor of the subfamily lived at approximately 15 Ma. Although the diversification of sigmodontines was not associated with the complete rise of the Panamanian Isthmus, we cannot exclude the hypothesis that this event played a relevant role in the evolution of the lineage during the Miocene.     

Phylogenetic relationships and evolution in Chrysosplenium (Saxifragaceae) based on matK sequence data

Chrysosplenium (Saxifragaceae) consists of 57 species widely distributed in temperate and arctic regions of the Northern Hemisphere, with two species restricted to the southern part of South America. Species relationships within the genus are highly problematic. The genus has traditionally been divided into two groups, sometimes recognized as sections (Oppositifolia and Alternifolia), based on leaf arrangement, or, alternatively, into 17 series. Based on morphological features, Hara suggested that the genus originated in South America and then subsequently migrated to the Northern Hemisphere. We conducted phylogenetic analyses of DNA sequences of the chloroplast gene matK for species of Chrysosplenium to elucidate relationships, test Hara's biogeographic hypothesis for the genus, and examine chromosomal and gynoecial diversification. These analyses revealed that both sections Oppositifolia and Alternifolia are monophyletic and form two large sister clades. Hence, leaf arrangement is a good indicator of relationships within this genus. Hara's series Pilosa and Macrostemon are each also monophyletic; however, series Oppositifolia, Alternifolia, and Nepalensia are clearly not monophyletic. MacClade reconstructions suggest that the genus arose in Eastern Asia, rather than in South America, with several independent migration events from Asia to the New World. In one well-defined subclade, species from eastern and western North America form a discrete clade, with Old World species as their sister group, suggesting that the eastern and western North American taxa diverged following migration to that continent. The South American species forms a clade with species from eastern Asia; this disjunction may be the result of ancient long-distance dispersal. Character mapping demonstrated that gynoecial diversification is dynamic, with reversals from inferior to half-inferior ovaries, as well as to ovaries that appear superior. Chromosomal evolution also appears to be labile with several independent origins of n = 12 (from an original number of n = 11) and multiple episodes of aneuploidy.     

THE EARLY DIVERSIFICATION HISTORY OF DIDELPHID MARSUPIALS: A WINDOW INTO SOUTH AMERICA'S “SPLENDID ISOLATION”

The geological record of South American mammals is spatially biased because productive fossil sites are concentrated at high latitudes. As a result, the history of mammalian diversification in Amazonia and other tropical biomes is largely unknown. Here we report diversification analyses based on a time‐calibrated molecular phylogeny of opossums (Didelphidae), a species‐rich clade of mostly tropical marsupials descended from a Late Oligocene common ancestor. Optimizations of habitat and geography on this phylogeny suggest that (1) basal didelphid lineages inhabited South American moist forests; (2) didelphids did not diversify in dry‐forest habitats until the Late Miocene; and (3) most didelphid lineages did not enter North America until the Pliocene. We also summarize evidence for an Early‐ to Middle‐Miocene mass extinction event, for which alternative causal explanations are discussed. To the best of our knowledge, this study provides the first published molecular‐phylogenetic evidence for mass extinction in any animal clade, and it is the first time that evidence for such an event (in any plant or animal taxon) has been tested for statistical significance. Potentially falsifying observations that could help discriminate between the proposed alternative explanations for didelphid mass extinction may be obtainable from diversification analyses of other sympatric mammalian groups.     

Mitochondrial DNA based phylogeny of the woodpecker genera Colaptes and Piculus,and implications for the history of woodpecker diversification in South America

The woodpecker genus Colaptes (flickers) has its highest diversity in South America and the closely related genus Piculus is restricted to South and Central America. Two species of flickers occur in North America, and one species is endemic to Cuba. We conducted a Bayesian phylogenetic analysis of three mitochondrial encoded genes (cyt b, COI, 12S rRNA) and confirmed that the two genera are paraphyletic. Three species historically classified as Piculus are actually flickers. We found that the Cuban endemic C. fernandinae is the most basal species within the flickers and that the Northern Flicker is the next most basal species within the Colaptes lineage. The South American clade is most derived. The age of the South American diversification is estimated to be 3.6 MY, which is synchronous with the emergence of the Isthmus of Panama. The pattern of diversification of South American flickers is common among South American woodpeckers. Although woodpeckers have their greatest diversity in South America, we hypothesize that woodpeckers (Family Picidae) originated in Eurasia, dispersed to North America via the Bering land bridge, and multiple lineages entered South America as the Isthmus approached its final closing.     

Phylogenetics of neotropical Platymiscium (Leguminosae: Dalbergieae): systematics, divergence times, and biogeography inferred from nuclear ribosomal and plastid DNA sequence data

Platymiscium is a neotropical legume genus of forest trees in the Pterocarpus clade of the pantropical "dalbergioid" clade. It comprises 19 species (29 taxa), distributed from Mexico to southern Brazil. This study presents a molecular phylogenetic analysis of Platymiscium and allies inferred from nuclear ribosomal (nrITS) and plastid (trnL, trnL-F and matK) DNA sequence data using parsimony and Bayesian methods. Divergence times are estimated using a Bayesian method assuming a relaxed molecular clock (multidivtime). Within the Pterocarpus clade, new sister relationships are recovered: Pterocarpus + Etaballia, Inocarpus + Tipuana and Paramachaerium + Maraniona. Our results support monophyly of Platymiscium, which is resolved into three major clades, each with distinct geographic ranges and ecological preferences. Diversification in Platymiscium has been driven by habitat fragmentation, invasion of novel geographic regions, and ecological diversification, revealing general patterns of diversification in the neotropics. We hypothesize that Platymiscium arose in dry habitats of South America and radiated northward. The Amazon basin was invaded twice both within the last 5.6 My and Central America twice before the closure of the Isthmus of Panama. Divergence times of the P. pubescens complex, restricted to seasonally dry tropical forests of South America, support pre-Pleistocene divergence in this biome.     

Temporal patterns of diversification and microendemism in Eastern Highland endemic barcheek darters (Percidae: Etheostomatinae)

Eastern North America is the location of the world's most species-rich temperate freshwater fish fauna. Hypotheses regarding the geographic and temporal scale of teleost diversification in this region have not been broadly investigated using absolute divergence time estimates among the constituent lineages. This study used time-calibrated molecular phylogenies estimated from mitochondrial and nuclear genes to investigate the temporal and geographic signatures of diversification within barcheek darters, a clade of allopatrically distributed species endemic to the Eastern Highlands. Results from divergence time estimates using an uncorrelated lognormal model suggest that the barcheek darters are an ancient group with a crown node estimate of 16.3 mya, 95% highest posterior density (HPD): [12.4, 20.5], and the clade is characterized by substantial intraspecific divergence times within several species. In particular, the Caney Fork endemic Etheostoma basilare comprises five strongly supported and deeply divergent clades with a most recent common ancestor estimated at 8.0 mya, 95% HPD: [5.6, 10.7]. These results are concordant with the hypothesis that geologically stable areas of eastern North America have facilitated both the generation and preservation of lineages across a substantial breadth of evolutionary time, and that allopatric speciation in darters has occurred at much smaller spatial scales than previously realized.     

Diversification patterns in the CES clade (Brassicaceae tribes Cremolobeae,Eudemeae, Schizopetaleae) in Andean South America

Dated molecular phylogenetic trees show that the Andean uplift had a major impact on South American biodiversity. For many Andean groups, accelerated diversification (radiation) has been documented. However, not all Andean lineages appear to have diversified following the model of rapid radiation, particularly in the central and southern Andes. Here, we investigated the diversification patterns for the largest South American‐endemic lineage of Brassicaceae, composed of tribes Cremolobeae, Eudemeae and Schizopetaleae (CES clade). Species of this group inhabit nearly all Andean biomes and adjacent areas including the Atacama–Sechura desert, the Chilean Matorral and the Patagonian Steppe. First, we studied diversification times and historical biogeography of the CES clade. Second, we analysed diversification rates through time, lineages and associated life forms. Results demonstrate that early diversification of the CES clade occurred in the early to mid‐Miocene (c. 12–19 Mya) and involved the central Andes, the southern Andes and the Patagonian Steppe, and the Atacama–Sechura desert. The Chilean Matorral and northern Andes were colonized subsequently in the early Pliocene (4–5 Mya). Diversification of the CES clade was recovered as a gradual process without any evidence for rate shifts or rapid radiation, in contrast to many other Andean groups analysed so far. Diversification time/rates and biogeographical patterns obtained for the CES clade are discussed and compared with patterns and conclusions reported for other Andean plant lineages.     

Life in proto‐Amazonia: Middle Miocene mammals from the Fitzcarrald Arch (Peruvian Amazonia)

The Middle Miocene has been identified as a time of great diversification in modern lineages now distributed in tropical South America, and when basic archetypal traits defining Amazonia appear, including climatic humid conditions, basic floral physiognomy and phylogenetic composition of modern rainforests. Nonetheless, Middle Miocene localities in South America are poorly known, especially at low latitudes where only one species‐rich locality, La Venta in Colombia, has been extensively studied. The present contribution describes the mammal fauna of Fitzcarrald, a new Middle Miocene local fauna from western Amazonia in Peru. Fitzcarrald is correlated with the Laventan South American Land Mammal Age based on the presence of taxa defining the ‘Miocochilius assemblage zone’ in La Venta. The mammalian fauna of Fitzcarrald comprises 24 taxa among cingulates, folivores, astrapotheres, notoungulates, litopterns, rodents, odontocetes and a possible marsupial. At this time, tropical South America was characterized by the presence of the Pebas megawetland, a huge lacustrine complex that provided unique ecological and environmental conditions most likely isolating northern South America from southern South America. These isolating conditions might have come to an end with its disappearance in the Late Miocene and the establishment of the subsequent Acre system, the predecessor fluvial system of modern Amazonia. Results of faunistic similarity between Fitzcarrald and other Miocene faunas throughout South America support these scenarios. The Fitzcarrald mammal fauna exhibits first appearance datums and last appearance datums of various taxa, showing that tropical South America has played a crucial role in the evolutionary history and biogeography of major clades, and revealing a more complex biological history than previously proposed, based on the record from the southern cone of the continent.     

Resolving the evolutionary history of Campanula (Campanulaceae) in western North America

Recent phylogenetic works have begun to address long-standing questions regarding the systematics of Campanula (Campanulaceae). Yet, aspects of the evolutionary history, particularly in northwestern North America, remain unresolved. Thus, our primary goal in this study was to infer the phylogenetic positions of northwestern Campanula species within the greater Campanuloideae tree. We combined new sequence data from 5 markers (atpB, rbcL, matK, and trnL-F regions of the chloroplast and the nuclear ITS) representing 12 species of Campanula with previously published datasets for worldwide campanuloids, allowing us to include approximately 75% of North American Campanuleae in a phylogenetic analysis of the Campanuloideae. Because all but one of North American Campanula species are nested within a single campanuloid subclade (the Rapunculus clade), we conducted a separate set of analyses focused specifically on this group. Our findings show that i) the campanuloids have colonized North America at least 6 times, 4 of which led to radiations, ii) all but one North American campanuloid are nested within the Rapunculus clade, iii) in northwestern North America, a C. piperi-C. lasiocarpa ancestor gave rise to a monophyletic Cordilleran clade that is sister to a clade containing C. rotundifolia, iv) within the Cordilleran clade, C. parryi var. parryi and C. parryi var. idahoensis exhibit a deep, species-level genetic divergence, and v) C. rotundifolia is genetically diverse across its range and polyphyletic. Potential causes of diversification and endemism in northwestern North America are discussed.     

Phylogeny and diversification of Valerianaceae (Dipsacales) in the southern Andes

The southern Andean clade of Valeriana provides an excellent model for the study of biogeography. Here we provide new data to help clarify phylogenetic relationships among the South American valerians, with special focus on taxa found in the southern Andes. We found that the southern Andean taxa formed a clade in maximum likelihood and maximum parsimony analyses, and used a Bayesian relaxed clock method to estimate divergence times within Valerianaceae. Our temporal results were similar to other studies, but we found greater variance in our estimates, suggesting that the species of Valeriana have been on the South American continent for some time, and have been successful at exploiting new niche opportunities that reflects the contemporary radiation. Regardless of the time frame for the radiation of the clade, the uptick in the rate of diversification in Valerianaceae appears correlated with a dispersal event from Central to South America. The appearance of Valeriana in the southern Andes (13.7 Ma) corresponds with the transition from closed forest on the western side of the Andes in central Chile to a more open Mediterranean woodland environment. This would suggest that the high species richness of Valerianaceae in South America is the result of multiple, smaller radiations such as the one in the southern Andes, that may or may not be geographically isolated. These smaller radiations may also be driven by species moving into new biomes (migration from a temperate to a more Mediterranean-type climate and into alpine). The degree to which different ecological and geological factors interact to drive diversification is difficult to ascertain. Likewise, without a better-resolved phylogeny it is impossible to determine the directionality of dispersal in this group; did they colonize the southern Andes first, then move northward as the central Andean alpine habitat became more widely available or vice versa?     

Molecular evidence for an Asian origin and a unique westward migration of species in the genus Castanea via Europe to North America

The genus Castanea (Fagaceae) is widely distributed in the deciduous forests of the Northern Hemisphere. The striking similarity between the floras of eastern Asia and those of eastern North America and the difference in chestnut blight resistance among species has been of interest to botanists for a century. To infer the biogeographical history of the genus, the phylogeny of Castanea was estimated using DNA sequence data from different regions of the chloroplast genome. Sequencing results support the genus Castanea as a monophyletic group with Castanea crenata as basal. The three Chinese species form a strongly supported sister clade to the North American and European clade. A unique westward expansion of extant Castanea species is hypothesized with Castanea originating in eastern Asia, an initial diversification within Asia during the Eocene followed by intercontinental dispersion and divergence between the Chinese and the European/North American species during the middle Eocene and a split between the European and the North American species in the late Eocene. The differentiation within North America and China might have occurred in early or late Miocene. The North America species are supported as a clade with C. pumila var. ozarkensis, the Ozark chinkapin, as the basal lineage, sister to the group comprising C. pumila var. pumila, the Allegheny chinkapin, and Castanea dentata, the American chestnut. Morphological evolution of one nut per bur in the genus may have occurred independently on two continents.     

Mitochondrial DNA phylogeny of the woodpecker genus Veniliornis (Picidae, Picinae) and related genera implies convergent evolution of plumage patterns

The woodpecker genus Veniliornis comprises 12 species, all restricted to the New World tropics. The seemingly distantly related genus Picoides is broadly distributed in Eurasia and North America with two putative species, P. lignarius and P. mixtus , occurring in South America. The two genera are clearly distinct with respect to general plumage colouration and patterning as well as habitat utilization and thus traditionally have been placed in different tribes. Phylogenetic analyses of mtDNA sequences from the COI and cyt b genes indicated that both genera are reciprocally paraphyletic. The two South American species of Picoides belong to a clade comprising most species of Veniliornis , but V. fumigatus of Central and north-western South America belongs to a clade comprising species of Picoides . The mtDNA tree also indicated that Veniliornis is not closely related to the genus Piculus, as is implicit in current classifications. Misclassifications involving Veniliornis at both the generic and tribal levels appear to result from convergent evolution of plumage traits in specific forest types. We infer that the common ancestor of Veniliornis entered South America approximately at the time the Isthmus of Panama was formed, and diversification within South America was rapid.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 87 , 611–624.     

Temporal diversification of Mesoamerican cichlid fishes across a major biogeographic boundary

The Mexican Neovolcanic Plateau sharply divides the vertebrate fauna of Mesoamerica where the climate of both the neotropics and temperate North America gradually blend. Only a few vertebrate groups such as the Heroine cichlids, distributed from South America to the Rio Grande in North America, are found both north and south of the Neovolcanic Plateau. To better understand the geography and temporal diversification of cichlids at this geologic boundary, we used mitochondrial DNA sequences of the cytochrome b (cyt b) gene to reconstruct the relationships of 52 of the approximately 80 species of Heroine cichlids in Mesoamerica. Our analysis suggests several cichlids in South America should be considered as part of the Mesoamerican Heroine clade because they and the cichlids north of the Isthmus of Panama are clearly supported as monophyletic with respect to all other Neotropical cichlids. We also recovered a group containing species in Paratheraps+Paraneetroplus+Vieja as the sister clade to Herichthys. Herichthys is the only cichlid clade north of the Mexican Plateau and it is monophyletic. Non-parametric rate smoothing of cichlid cyt b sequence resulted in an estimated divergence time of approximately 6 million years for Herichthys. This temporal diversification is concordant with divergence times estimated for anurans in the genus Bufo, a group that exhibits a similar geographic distribution. Our results indicate the 5-million-year-old extension of the Mexican Neovolcanic Plateau to the Gulf Coast of Mexico has strongly influenced the current transition between the vertebrate faunas of the Neotropics and Nearctic.     

Phylogeny and evolution of Perezia （Asteraceae： Mutisieae： Nassauviinae）

A molecular phylogenetic analysis of most of the species of Perezia reveals that, as traditionally defined, the genus is not monophyletic with two species more closely related to Nassauvia than to Perezia. In addition, our results show that Burkartia （Perezia） lanigera is related to Acourtia and is the only member of that clade in South America. The remaining species are monophyletic and show a pattern of an early split between a western temperate and an eastern subtropical clade of species. Within the western clade, the phylogeny indicates a pattern of diversification that proceeded from southern, comparatively low-elevation habitats to southern high-elevation habitats, and ultimately into more northern high-elevation habitats. The most derived clades are found in the high central Andes, where significant radiation has occurred.     

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.