Molecular phylogeny of Juglans (Juglandaceae): a biogeographic perspective

The eastern Asian and eastern North American disjunction in Juglans offers an opportunity to estimate the time since divergence of the Eurasian and American lineages and to compare it with paleobotanical evidence. Five chloroplast DNA noncoding spacer (NCS) sequences: trnT−trnF, psbA−trnH, atpB−rbcL, trnV-16S rRNA, and trnS-trnfM and data from earlier studies (matK, ITS, and nuclear RFLP) were used to reconstruct phylogeny and to estimate the divergence time of major lineages. Seventeen taxa from four sections of Juglans and two outgroup taxa, Pterocarya stenoptera and Carya illinoiensis were included. NCS data was congruent only with matK data. Both maximum parsimony (MP) and maximum likelihood (ML) cladograms were concordant at the sectional level and revealed three well-supported monophyletic clades corresponding to sections Juglans, Cardiocaryon, and Rhysocaryon in both NCS and combined analyses. The single extant American butternut, Juglans cinerea was placed within the poorly resolved, but well-supported Rhysocaryon. Placement of taxa within Rhysocaryon and Cardiocaryon were inconsistent between NCS and combined analyses. Overall, the results suggest that: (1) the NCS sequence divergence observed within and between sections of Juglans is low and the addition of matK data only marginally improved resolution within Rhysocaryon; (2) the early divergence of section Juglans in both MP and ML analyses of NCS and combined data implies its ancient origin in contrast to fossil evidence, which suggests the earliest divergence of sections Rhysocaryon and Cardiocaryon; and (3) the extant taxa may not hold the footprints to unravel the evolutionary history of the genus.     

Tropical rain forest conservation and the twin challenges of diversity and rarity

Data from a global network of large, permanent plots in lowland tropical forests demonstrate (1) that the phenomenon of tropical tree rarity is real and (2) that almost all the species diversity in such forests is due to rare species. Theoretical and empirically based reasoning suggests that many of these rare species are not as geographically widespread as previously thought. These findings suggest that successful strategies for conserving global tree diversity in lowland tropical forests must pay much more attention to the biogeography of rarity, as well as to the impact of climate change on the distribution and abundance of rare species. Because the biogeography of many tropical tree species is poorly known, a high priority should be given to documenting the distribution and abundance of rare tropical tree species, particularly in Amazonia, the largest remaining tropical forested region in the world.     

Molecular phylogeny of Mentawai macaques: taxonomic and biogeographic implications

In order to elucidate the evolutionary history and taxonomy of the Mentawai macaques, we sequenced a 567 base pairs (bp) long fragment of the mitochondrial cytochrome b gene from 39 individuals representing pigtailed macaque populations from Siberut, Sipora, South Pagai, and Sumatra. Pairwise difference analyses carried out within and among populations have shown, that: (1) variation within populations is relative low, (2) variation among populations is increased, and (3) pairwise differences within and among the populations from Sipora and South Pagai are in the same range. From phylogenetic tree reconstructions including further macaque species, we detected a paraphyletic origin of Mentawai macaques with the Siberut population more closely related to Macaca nemestrina from Sumatra, than it is to populations from the Southern islands. Based on these results, we favour a scenario in that macaques entered the Mentawai islands by two independent colonisation events. Taking together the paraphyletic origin of Mentawai macaques and the genetic differences detected among pigtailed macaque populations, which are comparable with those observed among the seven Sulawesi macaque species, we propose to separate macaques from Siberut and Sipora, North and South Pagai into two distinct species, Macaca siberu and Macaca pagensis, respectively.     

Molecular phylogeny and morphometric analyses reveal deep divergence between Amazonia and Atlantic Forest species of Dendrophryniscus

Dendrophryniscus is an early diverging clade of bufonids represented by few small-bodied species distributed in Amazonia and the Atlantic Forest. We used mitochondrial (414 bp of 12S, 575 bp of 16S genes) and nuclear DNA (785 bp of RAG-1) to investigate phylogenetic relationships and the timing of diversification within the genus. These molecular data were gathered from 23 specimens from 19 populations, including eight out of the 10 nominal species of the genus as well as Rhinella boulengeri. Analyses also included sequences of representatives of 18 other bufonid genera that were publically available. We also examined morphological characters to analyze differences within Dendrophryniscus. We found deep genetic divergence between an Amazonian and an Atlantic Forest clade, dating back to Eocene. Morphological data corroborate this distinction. We thus propose to assign the Amazonian species to a new genus, Amazonella. The species currently named R. boulengeri, which has been previously assigned to the genus Rhamphophryne, is shown to be closely related to Dendrophryniscus species. Our findings illustrate cryptic trends in bufonid morphological evolution, and point to a deep history of persistence and diversification within the Amazonian and Atlantic rainforests. We discuss our results in light of available paleoecological data and the biogeographic patterns observed in other similarly distributed groups.     

Molecular and morphological analysis of the critically endangered Fijian iguanas reveals cryptic diversity and a complex biogeographic history

The Pacific iguanas of the Fijian and Tongan archipelagos are a biogeographic enigma in that their closest relatives are found only in the New World. They currently comprise two genera and four species of extinct and extant taxa. The two extant species, Brachylophus fasciatus from Fiji, Tonga, and Vanuatu and Brachylophus vitiensis from western Fiji, are of considerable conservation concern with B. vitiensis listed as critically endangered. A recent molecular study has shown that Brachylophus comprised three evolutionarily significant units. To test these conclusions and to reevaluate the phylogenetic and biogeographic relationships within Brachylophus, we generated an mtDNA dataset consisting of 1462 base pairs for 61 individuals from 13 islands, representing both Brachylophus species. Unweighted parsimony analyses and Bayesian analyses produced a well-resolved phylogenetic hypothesis supported by high bootstrap values and posterior probabilities within Brachylophus. Our data reject the monophyly of specimens previously believed to comprise B. fasciatus. Instead, our data demonstrate that living Brachylophus comprise three robust and well-supported clades that do not correspond to current taxonomy. One of these clades comprises B. fasciatus from the Lau group of Fiji and Tonga (type locality for B. fasciatus), while a second comprises putative B. fasciatus from the central regions of Fiji, which we refer to here as B. n. sp. Animals in this clade form the sister group to B. vitiensis rather than other B. fasciatus. We herein describe this clade as a new species of Brachylophus based on molecular and morphological data. With only one exception, every island is home to one or more unique haplotypes. We discuss alternative biogeographic hypotheses to explain their distribution in the Pacific and the difficulties of distinguishing these. Together, our molecular and taxonomic results have important implications for future conservation initiatives for the Pacific iguanas.     

Molecular phylogeny of elapid snakes and a consideration of their biogeographic history

Evolutionary relationships among the major elapid clades, particularly the taxonomic position of the partially aquatic sea kraits (Latkauda) and the fully aquatic true sea snakes have been the subject of much debate. To discriminate among existing phylogenetic and biogeographic hypotheses, portions of both the 16S rRNA and cytochrome b mitochondrial DNA genes were sequenced from 16 genera and 17 species representing all major elapid snake clades from throughout the world and two non-elapid outgroups. This sequence data yielded 181 informative sites under parsimony. Parsimony analyses of the separate data sets produced trees of broad agreement although less well supported than the single most parsimonious tree resulting from the combined analyses. These results support the following hypotheses: (1) the Afro-Asian cobra radiation forms one or more sister groups to other elapids, (2) American and Asian coral snakes form a clade, corroborating morphological studies, (3) Bungarus forms a sister group to the hydrophiines comprised of Latkauda, terrestrial Australo-Papuan elapids and true sea snakes, (4) Latkauda and true sea snakes do not form a monophyletic group but instead each group shares an independent history with terrestrial Australo-Papuan elapids, corroborating previous studies, (5) a lineage of Melanesian elapids forms the sister group to Latkauda, terrestrial Australian species and true sea snakes. In agreement with previous morphologically based studies, the sequence data suggests that Bungarus and Latkauda represent transitional clades between the elapine 'palatine erectors' and hydrophiine 'palatine draggers'. Both intra and inter-clade genetic distances are considerable, implying that each of the major radiations have had long independent histories. I suggest an African, Asian, or Afro-Asian origin for elapids as a group, with independent Asian origins for American coral snakes and the hydrophiines.     

Molecular phylogeny and biogeographic history of the piculets (Piciformes: Picumninae)

The subfamily Picumninae (piculets) includes 3 genera and 30 species of tiny and short-tailed woodpeckers with a pantropical distribution. Within the Picumninae, two cases of intercontinentally disrupted distributions at the genus level occur. The first one concerns the genus Sasia (one species in Africa and two in southeast Asia) while the second concerns Picumnus (one species in southeast Asia and 25 in South America). These disrupted distributions, as well as several morphological differences, have lead some authors to place the African representative of Sasia and the southeast Asian representative of Picumnus in their own monotypic genera ( Verreauxia and Vivia , respectively). To address the taxonomic status and biogeographic history of the piculets, we sequenced 2676 bp of DNA from one mitochondrial (ND2) and two nuclear markers (myoglobin intron 2 and β-fibrinogen intron 7). Monophyly of Picumninae could not be recovered with confidence, while monophyly of Sasia and Picumnus were always strongly supported. Molecular dating analyses revealed that the splits both between the African and Indo-Malayan Sasia and between the New World and Old World Picumnus occurred at ca 7.9 Myr BP. This time corresponds to the beginning of the formation of the northern Hemisphere ice sheets and the accompanying expansion of grasslands throughout the world. The spread of open areas in the northern parts of Eurasia and America prevented gene flow between tropical forest birds, such as the piculets, in Africa, southeast Asia and South America, respectively.     

Molecular phylogeny and biogeography of Malagasy frogs of the genus Gephyromantis

The genus Gephyromantis is a clade within the Malagasy-Comoroan family Mantellidae composed of rainforest frogs that live and breed to varying degrees independently from water. Based on DNA sequences of five mitochondrial and five nuclear genes we inferred the phylogeny of these frogs with full taxon coverage at the species level. Our preferred consensus tree from a partitioned Bayesian analysis of 5843 base pairs of 51 nominal and candidate species supports various major clades within the genus although the basal relationships among these remain unresolved. The data provide strong evidence for the monophyly of the subgenera Gephyromantis (after exclusion of Gephyromantis klemmeri), Laurentomantis, Vatomantis, and Phylacomantis. Species assigned to the subgenus Duboimantis belong to two strongly supported clades of uncertain relationships. G. klemmeri, previously in the subgenus Gephyromantis, was placed with high support sister to the Laurentomantis clade, and the Laurentomantis + G. klemmeri clade was sister to Vatomantis. A reconstruction of ancestral distribution areas indicates a diversification of several subgenera in the northern biogeographic regions of Madagascar and the dispersal out of northern Madagascar for several clades.     

Molecular phylogeny of the marmots (Rodentia: Sciuridae): tests of evolutionary and biogeographic hypotheses

There are 14 species of marmots distributed across the Holarctic, and despite extensive systematic study, their phylogenetic relationships remain largely unresolved. In particular, comprehensive studies have been lacking. A well-supported phylogeny is needed to place the numerous ecological and behavioral studies on marmots in an evolutionary context. To address this situation, we obtained complete cytochrome (cyt) b sequences for 13 of the species and a partial sequence for the 14th. We applied a statistical approach to both phylogeny estimation and hypothesis testing, using parsimony and maximum likelihood-based methods. We conducted statistical tests on a suite of previously proposed hypotheses of phylogenetic relationships and biogeographic histories. The cyt b data strongly support the monophyly of Marmota and a western montane clade in the Nearctic. Although some other scenarios cannot be rejected, the results are consistent with an initial diversification in North America, followed by an invasion and subsequent rapid diversification in the Palearctic. These analyses reject the two major competing hypotheses of M. broweri's phylogenetic relationships--namely, that it is the sister species to M. camtschatica of eastern Siberia, and that it is related closely to M. caligata of the Nearctic. The Alaskan distribution of M. broweri is best explained as a reinvasion from the Palearctic, but a Nearctic origin can not be rejected. Several other conventionally recognized species groups can also be rejected. Social evolution has been homoplastic, with large colonial systems evolving in two groups convergently. The cyt b data do not provide unambiguous resolution of several basal nodes in the Palearctic radiation, leaving some aspects of pelage and karyotypic evolution equivocal.     

Landscape Transformations and loss of Atlantic Forests: challenges for conservation

Regions of intense fragmentation and landscape transformation can indicate patterns of conversion of forest areas in space and time, challenging the resilience of ecosystems and driving the degradation of natural resources. In this study, we analyzed the dynamics of use, loss, and gain of Atlantic forests in the southern region of Bahia State in the last thirty-four years (1985–2019) based on pre and post-implementation of forest production policies. The area has ecological, historical, and cultural importance, and is the most conserved portion of the Atlantic Forest in northeastern Brazil. From the remote sensing products of the MapBiomas Project and spatial analyses of land use and forests, we evaluated a conflicted region that has 751 km of coastline and seventy municipalities. Our results indicate a degraded landscape, with 59% of the territory occupied by anthropogenic activities and intense fragmentation. The planting of eucalyptus forests and pasture stood out as landscape modifiers. The results show a loss of 328,595 ha of Atlantic Forest in the period under study, with a large part of this area being replaced by planted forests of Eucalyptus sp derivated the policies economics of the sector. It is urgent to consider the recovery of the Atlantic domain, prioritizing the capacity of ecosystems, especially in the Decade of Restoration.     

Optimizing conservation of forest diversity: a country-wide approach in Mexico

A recent vegetation study [Palacio-Prieto et al. (2000) Bol Inst Geogr UNAM 43:183–203] showed that Mexico’s forest area has declined to 33.3%, from originally 52.0% of the country’s land area. In order to assess strategies for tree diversity conservation, we compiled a list of 846 tree species native to Mexico, and determined for each the presence or absence in 234 geographical squares of 1° latitude by 1° longitude (approximately 106 × 106 km). On the average, any two squares shared only 6% of their species composition. Using a standard optimization method from engineering and economics [Dantzig (1963) Linear programming and extensions. Princeton University Press, Princeton, NJ, USA, 625 p], we determined the minimally necessary land area in Mexico to conserve the 846 tree species, while securing that each species is found in an area of (approximately) 1,100 km² of currently existing forest vegetation. Furthermore, we took into account 15 existing protected areas with a size of at least 1,100 km² each. With these constraints, the total minimum area needed to conserve all 846 tree species is 45,136 km² of currently existing forest vegetation, or 2.3% of Mexico’s surface. While this analysis can be refined with subsequent field work, the proposed reserve network indicates that efficient land use planning on a national scale may be able to conserve tree species diversity in a relatively small portion of Mexico, even after severe deforestation has taken place.     

Tuberculina-Helicobasidium: Host specificity of the Tuberculina-stage reveals unexpected diversity within the group

Tuberculina species are mitosporic parasites of rust fungi. It was demonstrated recently that Tuberculina represents the asexual life stage of the plant-parasitic genus Helicobasidium. Here we reveal the host specificities of Tuberculina and Helicobasidium species on rust fungal hosts by means of infection experiments and molecular analyses. We inoculated species of the rust genera Chrysomyxa, Coleosporium, Cronartium, Gymnosporangium, Puccinia, Tranzschelia and Uromyces with conidia and with basidiospores of Helicobasidium longisporum and H. purpureum and with conidia of Tuberculina maxima, T. persicina and T. sbrozzii. In addition we analyzed base sequences from the nuclear ITS region of 51 Tuberculina and Helicobasidium specimens collected in the field together with the sequences from the Tuberculina infections obtained by infection experiments. The resulting data show that at least six monophyletic lineages are within the Tuberculina/Helicobasidium-group that can be unambiguously distinguished by combining molecular and morphological characters and by specific host spectra of the Tuberculina-stage. This diversity opens up new vistas on the evolution of this exceptional mycoparasitic-phytoparasitic fungal group.     

Molecular phylogeny of the Astrophorida (Porifera, Demospongiae(p)) reveals an unexpected high level of spicule homoplasy

Background

The Astrophorida (Porifera, Demospongiae ^p) is geographically and bathymetrically widely distributed. Systema Porifera currently includes five families in this order: Ancorinidae, Calthropellidae, Geodiidae, Pachastrellidae and Thrombidae. To date, molecular phylogenetic studies including Astrophorida species are scarce and offer limited sampling. Phylogenetic relationships within this order are therefore for the most part unknown and hypotheses based on morphology largely untested. Astrophorida taxa have very diverse spicule sets that make them a model of choice to investigate spicule evolution.

Methodology/Principal Findings

With a sampling of 153 specimens (9 families, 29 genera, 89 species) covering the deep- and shallow-waters worldwide, this work presents the first comprehensive molecular phylogeny of the Astrophorida, using a cytochrome c oxidase subunit I (COI) gene partial sequence and the 5′ end terminal part of the 28S rDNA gene (C1-D2 domains). The resulting tree suggested that i) the Astrophorida included some lithistid families and some Alectonidae species, ii) the sub-orders Euastrophorida and Streptosclerophorida were both polyphyletic, iii) the Geodiidae, the Ancorinidae and the Pachastrellidae were not monophyletic, iv) the Calthropellidae was part of the Geodiidae clade (Calthropella at least), and finally that v) many genera were polyphyletic (Ecionemia, Erylus, Poecillastra, Penares, Rhabdastrella, Stelletta and Vulcanella).

Conclusion

The Astrophorida is a larger order than previously considered, comprising ca. 820 species. Based on these results, we propose new classifications for the Astrophorida using both the classical rank-based nomenclature (i.e., Linnaean classification) and the phylogenetic nomenclature following the PhyloCode, independent of taxonomic rank. A key to the Astrophorida families, sub-families and genera incertae sedis is also included. Incongruences between our molecular tree and the current classification can be explained by the banality of convergent evolution and secondary loss in spicule evolution. These processes have taken place many times, in all the major clades, for megascleres and microscleres.     

From forest to cropland and pasture systems: a critical review of soil organic carbon stocks changes in Amazonia

The impact of deforestation on soil organic carbon (SOC) stocks is important in the context of climate change and agricultural soil use. Trends of SOC stock changes after agroecosystem establishment vary according to the spatial scale considered, and factors explaining these trends may differ sometimes according to meta‐analyses. We have reviewed the knowledge about changes in SOC stocks in Amazonia after the establishment of pasture or cropland, sought relationships between observed changes and soil, climatic variables and management practices, and synthesized the δ¹³C measured in pastures. Our dataset consisted of 21 studies mostly synchronic, across 52 sites (Brazil, Colombia, French Guiana, Suriname), totalling 70 forest–agroecosystem comparisons. We found that pastures (n = 52, mean age = 17.6 years) had slightly higher SOC stocks than forest (+6.8 ± 3.1 %), whereas croplands (n = 18, mean age = 8.7 years) had lower SOC stocks than forest (?8.5 ± 2.9 %). Annual precipitation and SOC stocks under forest had no effect on the SOC changes in the agroecosystems. For croplands, we found a lower SOC loss than other meta‐analyses, but the short time period after deforestation here could have reduced this loss. There was no clear effect of tillage on the SOC response. Management of pastures, whether they were degraded/nominal/improved, had no significant effect on SOC response. δ¹³C measurements on 16 pasture chronosequences showed that decay of forest‐derived SOC was variable, whereas pasture‐derived SOC was less so and was characterized by an accumulation plateau of 20 Mg SOC ha^?1 after 20 years. The large uncertainties in SOC response observed could be derived from the chronosequence approach, sensitive to natural soil variability and to human management practices. This study emphasizes the need for diachronic and long‐term studies, associated with better knowledge of agroecosystem management.     

Beta diversity of frogs in the forests of New Guinea, Amazonia and Europe: contrasting tropical and temperate communities

Aim To test the hypothesis that animal communities within environmentally relatively uniform lowland forests are characterized by low beta diversity, both in tropical and in temperate areas. Location Lowland forests in the basins of the Sepik and Ramu rivers in New Guinea, the Amazon river in Bolivia, and the Elbe and Dyje rivers in the Czech Republic. Methods A network of 5–6 study sites spanning distances from 20–80 to 300–500 km in each study area was systematically surveyed for all frogs, using visual detection and call tracking. The community data were analysed for alpha and beta diversity. Results Local (alpha) diversity of frog communities was similar in the two tropical areas, New Guinea (mean ± SE of 22 ± 1.4 species per site) and Amazonia (24 ± 1.7 species), but was significantly lower in Europe (8 ± 0.8 species). In Amazonia, 36 of the total of 70 species were recorded from single sites. In contrast, widespread species dominated in Europe, whereas New Guinea exhibited an intermediate pattern with both local and widespread species well represented. The rate of species accumulation across different sites was lowest in Europe, intermediate in New Guinea and highest in Amazonia. The regional species diversity, expressed as the combined number of species from five study sites, was 1.5 times higher than the local species diversity at a single site in Europe, 2.0 times higher in New Guinea and 2.7 times higher in Amazonia. The proportion of species shared between communities decreased with geographic distance in New Guinea and Europe, but not in Amazonia. Main conclusions Frog communities in the lowland tropical rain forests of New Guinea and Amazonia had similar numbers of species, but differed in their beta diversity. More species in Amazonia had restricted distributions than in New Guinea. Both tropical areas had markedly higher alpha and beta diversity than the temperate area in Europe.     

Molecular phylogeny of French Guiana Hylinae: implications for the systematic and biodiversity of the Neotropical frogs

In this study we used nucleotide sequences from a segment of mitochondrial 16S ribosomal DNA gene to investigate the evolutionary relationships of some French Guiana Hylinae. New sequences, representing the members of different French Guiana frogs-five specimens of the Scinax genus, two Hyla, one Osteocephalus, one Hyalinobatrachium and two Rana as out-group-were examined. In addition, 26 sequences available from GenBank database representing the other subfamilies of the Hylidae were added to our study. This work allowed us to clarify relationships within the four hylids subfamilies (Pelodryadinae, Phyllomedusinae, Hemiphractinae and Hylinae) and the phylogenetic placement of the enigmatic Scinax genus within the Hylidae. We found that: (1) the Scinax genus displays a high level of differentiation in comparison to two other genera (Litoria and Hyla) belonging to 'Hylidae' family; (2) the Hylinae are paraphyletic given the position of the Litoria, which was the sister-group of the Hyla and the Osteocephalus genera; (3) the anterior works and our results (based on two different data sets) showed the paraphyly of the Hylidae questioning the validity of this family; (4) the reassessment of these different taxonomic groups will induce a huge implication on the estimation (past, present and future) of the biodiversity (in Neotropical frogs).     

Molecular phylogeny of plethodonine salamanders and hylid frogs: statistical analysis of protein comparisons.

The bootstrapping method of determining confidence in the topology of phylogenetic trees has been applied to electrophoretic protein data for two groups of amphibians: salamanders of two North American genera (Aneides and Plethodon) of the tribe Plethodontini and Holarctic hylid frogs. Some current methods of phylogenetic reconstruction for electrophoretic protein data have been evaluated by comparing the trees obtained from molecular data sets with available morphological data. Molecular data on the phylogenetic relationships of Aneides and Plethodon, data obtained from electrophoretic and immunological studies, indicate that Aneides probably was derived from western Plethodon subsequent to the separation of eastern and western Plethodon. Thus Plethodon very likely is a paraphyletic genus. The extremely low rate of morphological evolution in Plethodon compared with that in Aneides causes difficulty in indicating their evolutionary relationships taxonomically because there are no synapomorphic morphological characters that define either eastern or western Plethodon, whereas there are several for the genus Aneides. Thus molecular data alone probably indicate the evolutionary relationships of the species in these genera. Highton and Larson's (1979) arrangement of species of Plethodon into eight species groups is supported. The topologies of the unweighted pair-group method using arithmetic means (UPGMA) and distance Wagner trees were compared with independent morphological and molecular data on the relationships of the 28 plethodonine species. It was found that UPGMA trees indicate relationships that are more in agreement with other information than are those provided by distance Wagner trees. The use of the bootstrap technique indicates that the topologies of UPGMA trees are better supported statistically than are the topologies of distance Wagner trees. Moreover, different addition criteria produce a variety of distance Wagner trees with different topologies, each with several groupings that are not supported statistically. It is concluded that considerable caution should be used in interpreting the topology of distance Wagner trees. Very similar results were obtained with a second data set on 30 taxa of Holarctic hylid frogs. Trees obtained by the neighbor-joining method are more in agreement with UPGMA phenograms and other data, so this method of phylogenetic reconstruction may be useful to systematists not willing to assume constant rates of evolution.(ABSTRACT TRUNCATED AT 400 WORDS)     

Molecular phylogeny, biogeography and insights into the origin of parthenogenesis in the Neotropical genus Leposoma (Squamata: Gymnophthalmidae): Ancient links between the Atlantic Forest and Amazonia

Leposoma is a conspicuous component of leaf litter herpetofauna of South and Central American rainforests. The 15 bisexual and one parthenogenetic species are allocated to the parietale and scincoides groups based on morphology. Phylogenetic analyses of 1830 bp (mtDNA + nuclear) were performed on 63 specimens of four species from Amazonian and Panamanian rainforests, and six species and one undescribed form from the Atlantic Forest. Different methods of tree reconstruction were explored, with Anotosaura vanzolinia and Colobosauroides cearensis as outgroups. The monophyly of the parietale and scincoides groups is strongly supported. Contrary to previous hypotheses suggesting a recent contact between Atlantic and Amazon forests, our estimates point to an initial split in Miocene. The position of Leposoma baturitensis, endemic to relictual forests in the semiarid Caatingas northeastern Brazil, and its divergence from the remaining species of the Atlantic Forest, suggests an ancient isolation with no indication of a secondary contact with forests of the eastern coast. Our data do not permit unambiguous assignment of parental species of the unisexual Leposoma percarinatum or the mechanism involved in the origin of parthenogenesis, but revealed two highly divergent diploid and triploid lineages within L. percarinatum, indicating that the unisexuals represent a species complex.     

Molecular phylogeny of Malagasy poison frogs,genus Mantella (Anura: Mantellidae): homoplastic evolution of colour pattern in aposematic amphibians

We studied the evolution of colour pattern in Malagasy poison frogs, genus Mantella, a group of diurnal and toxic frogs endemic to Madagascar. Based on a phylogeny reconstructed using 1130 bp of the mitochondrial 16S rRNA gene, the genus can be divided into five species groups. Within some of these groups, interspecific genetic divergences were very low (1.2–2.8% sequence divergence) while colour patterns were markedly different. In contrast, Mantella madagascariensis and M. baroni, two species which show extremely similar dorsal coloration patterns, were not included in the same clade. This conclusion was supported by high bootstrap values and by significant rejection of alternative topologies using KH-tests. Analysis of colour patterns and tentative reconstruction of ancestral states yielded five character states shared by these two species but not by their respective sister species, M. aurantiaca and M. nigricans. Considering these detailed similarities as symplesiomorphic therefore requires the assumption of multiple reversals in other species, whereas a homoplastic colour evolution in the sympatric M. madagascariensis andM. baroni appears as most parsimonious. This parallelism may have been triggered by MÜllerian mimicry. However, additional data is necessary to support this hypothesis.     

Molecular phylogeny of Allograpta (Diptera, Syrphidae) reveals diversity of lineages and non-monophyly of phytophagous taxa

Phylogenetic relationships of genera Allograpta, Sphaerophoria and Exallandra (Diptera, Syrphidae) were analyzed based on sequence data from the mitochondrial protein-coding gene cytochrome c oxidase subunit I (COI) and the nuclear 28S and 18S ribosomal RNA genes. The three genera are members of the subfamily Syrphinae, where nearly all members feed as larvae on soft-bodied Hemiptera and other arthropods. Phytophagous species have recently been discovered in two subgenera of Allograpta, sg Fazia and a new subgenus from Costa Rica. Phylogenetic analyses of the combined datasets were performed using parsimony, under static alignment and direct optimization, maximum likelihood and Bayesian inference. Congruent topologies obtained from all the analyses indicate paraphyly of the genus Allograpta with respect to Sphaerophoria and Exallandra. Exallandra appears embedded in the genus Sphaerophoria, and both genera are placed within Allograpta. The distribution of phytophagous taxa in Allograpta indicates that plant feeding evolved at least twice in this group.