Wide but not impermeable: Testing the riverine barrier hypothesis for an Amazonian plant species

Wallace's riverine barrier hypothesis postulates that large rivers, such as the Amazon and its tributaries, reduce or prevent gene flow between populations on opposite banks, leading to allopatry and areas of species endemism occupying interfluvial regions. Several studies have shown that two major tributaries, Rio Branco and Rio Negro, are important barriers to gene flow for birds, amphibians and primates. No botanical studies have considered the potential role of the Rio Branco as a barrier, while a single botanical study has evaluated the Rio Negro as a barrier. We studied an Amazon shrub, Amphirrhox longifolia (A. St.‐Hil.) Spreng (Violaceae), as a model to test the riverine barrier hypothesis. Twenty‐six populations of A. longifolia were sampled on both banks of the Rio Branco and Rio Negro in the core Amazon Basin. Double‐digest RADseq was used to identify 8,010 unlinked SNP markers from the nuclear genome of 156 individuals. Data relating to population structure support the hypothesis that the Rio Negro acted as a significant genetic barrier for A. longifolia. On the other hand, no genetic differentiation was detected among populations spanning the narrower Rio Branco, which is a tributary of the Rio Negro. This study shows that the strength of riverine barriers for Amazon plants is dependent on the width of the river separating populations and species‐specific dispersal traits. Future studies of plants with contrasting life history traits will further improve our understanding of the landscape genetics and allopatric speciation history of Amazon plant diversity.     

Mitochondrial phylogenetics of the goshawk Accipiter [gentilis] superspecies

The Northern Goshawk Accipiter gentilis is a medium‐sized bird of prey inhabiting boreal and temperate forests. It has a Holarctic distribution with 10 recognized subspecies. Traditionally, it has been placed within the Accipiter [gentilis] superspecies, together with Henst's Goshawk A. henstii, the Black Sparrowhawk A. melanoleucus, and Meyer's Goshawk A. meyerianus. While those four taxa are geographically separated from each other, hence referred to as allospecies, their phylogenetic relationships are still unresolved. In the present study, we performed phylogenetic analyses on the Accipiter [gentilis] superspecies, including all recognized subspecies of all four allospecies, using partial sequences of two marker loci of the mitochondrial genome, the control region and the cytochrome b gene. We found a deep split within A. gentilis into two monophyletic groups, a Nearctic clade (three subspecies) and a Palearctic clade (seven subspecies). The Palearctic clade is closely related to A. meyerianus, and together these two were more closely related to the other Old World taxa A. henstii and A. melanoleucus, which in turn were reciprocally monophyletic sister species. As a consequence, A. gentilis as usually conceived (including all Holarctic subspecies) was non‐monophyletic. We found a strong genetic homogeneity within Palearctic A. gentilis despite the fact that it comprises seven subspecies distributed from the Atlantic coast in Western Europe to Eastern Siberia. Relationships between the four clades could not be resolved unambiguously. Our results, if confirmed by more integrative data, would imply a taxonomic revision of Nearctic A. gentilis into a separate allospecies, Accipiter [gentilis] atricapillus.     

Divergent mitochondrial lineages arose within a large,panmictic population of the Savannah sparrow (Passerculus sandwichensis)

Unusual patterns of mtDNA diversity can reveal interesting aspects of a species’ biology. However, making such inferences requires discerning among the many alternative scenarios that could underlie any given mtDNA pattern. Next‐generation sequencing methods provide large, multilocus data sets with increased power to resolve unusual mtDNA patterns. A mtDNA‐based phylogeography of the Savannah sparrow (Passerculus sandwichensis) previously identified two sympatric, but divergent (~2%) clades within the nominate subspecies group and a third clade that consisted of birds sampled from northwest Mexico. We revisited the phylogeography of this species using a population genomic data set to resolve the processes leading to the evolution of sympatric and divergent mtDNA lineages. We identified two genetic clusters in the genomic data set corresponding to (a) the nominate subspecies group and (b) northwestern Mexico birds. Following divergence, the nominate clade maintained a large, stable population, indicating that divergent mitochondrial lineages arose within a panmictic population. Simulations based on parameter estimates from this model further confirmed that this demographic history could produce observed levels of mtDNA diversity. Patterns of divergent, sympatric mtDNA lineages are frequently interpreted as admixture of historically isolated lineages. Our analyses reject this interpretation for Savannah sparrows and underscore the need for genomic data sets to resolve the evolutionary mechanisms behind anomalous, locus‐specific patterns.     

Phylogeny of the hermit hummingbirds (trochilidae: Phaethornithinae)

A phylogeny of the hummingbirds of the genera Ramphodon, Eutoxeres, Glaucis, Threnetes, and Phaethornis is presented on the basis of external morphological characters. All 34 species of hermit hummingbirds are included in this study. Differences in 96 characters were examined with regard to their apomorphic (derived) or plesiomor‐phic (primitive) states, resulting in evolutionary trees drawn on the basis of cladistic principles. The most important results are: (1) “Ramphodon “ dohrnii is closer to Glaucis than to Ramphodon; (2) “Phaethornis” gounellei is the sister species to all Phaethornis and merits reevaluation as a separate genus, Anopetia; (3) Phaethornis philippii and P. koepckeae are the sister group to P. syrmatophorus, their straight bill having evolved independently of P. bourcieri; (4) the Phaethornis superciliosus/malaris species group includes P. longirostris as a third species; (5) Phaethornis subochraceus, P. pretrei, and P. augusti share a common ancestor, and (6) Phaethornis longuemareus (sensu Peters 1945) is polyphyletic, being comprised of four seperate species. Due to the lack of synapomorphies, the relationships of some species cannot be reliably determined on the basis of external morphological characters alone.     

The genus Pseudo-nitzschia (Bacillariophyceae) in a temperate estuary with description of two new species: Pseudo-nitzschia plurisecta sp. nov. and Pseudo-nitzschia abrensis sp. nov.

The genus Pseudo‐nitzschia contains potentially toxic species of problematic taxonomy, making it one of the most intensively studied diatom genera. The study of 35 clonal strains isolated from the Bilbao estuary, an area that experiences recurrent blooms of Pseudo‐nitzschia, revealed the presence of two new species, P. abrensis and P. plurisecta, differing from their congeners in both morphology and gene sequence. The morphological features were analyzed by LM and EM, whereas molecular analyses were based on the internal transcribed spacer (ITS) and large subunit (LSU) regions of the rDNA. P. plurisecta appears closely related to P. cuspidata/P. pseudodelicatissima in the phylogenetic tree, whereas P. abrensis forms a moderately supported clade with P. heimii/P. subpacifica and P. caciantha/P. circumpora. Comparison of the secondary structure of ITS2 regions reveals marked differences in the most highly conserved regions among related taxa. Morphologically, the new species differ from their closest congeners in the arrangement of the poroid sectors and the density of valve striae and fibulae. The two species share similar pigment composition, and belong to the group of Pseudo‐nitzschia species containing only chlorophyll c₂ and c₃.     

Are Prorocentrum hoffmannianum and Prorocentrum belizeanum (DINOPHYCEAE,PROROCENTRALES), the same species? An integration of morphological and molecular data

The taxonomic assignment of Prorocentrum species is based on morphological characteristics; however, morphological variability has been found for several taxa isolated from different geographical regions. In this study, we evaluated species boundaries of Prorocentrum hoffmannianum and Prorocentrum belizeanum based on morphological and molecular data. A detailed morphological analysis was done, concentrating on the periflagellar architecture. Molecular analyses were performed on partial Small Sub‐Unit (SSU) rDNA, partial Large Sub‐Unit (LSU) rDNA, complete Internal Transcribed Spacer Regions (ITS1‐5.8S‐ITS2), and partial cytochrome b (cob) sequences. We concatenated the SSU‐ITS‐LSU fragments and constructed a phylogenetic tree using Bayesian Inference (BI) and maximum likelihood (ML) methods. Morphological analyses indicated that the main characters, such as cell size and number of depressions per valve, normally used to distinguish P. hoffmannianum from P. belizeanum, overlapped. No clear differences were found in the periflagellar area architecture. Prorocentrum hoffmannianum and P. belizeanum were a highly supported monophyletic clade separated into three subclades, which broadly corresponded to the sample collection regions. Subtle morphological overlaps found in cell shape, size, and ornamentation lead us to conclude that P. hoffmanianum and P. belizeanum might be considered conspecific. The molecular data analyses did not separate P. hoffmannianum and P. belizeanum into two morphospecies, and thus, we considered them to be the P. hoffmannianum species complex because their clades are separated by their geographic origin. These geographic and genetically distinct clades could be referred to as ribotypes: (A) Belize, (B) Florida‐Cuba, (C1) India, and (C2) Australia.     

Genetic variation in Tertiary relics: The case of eastern‐Mediterranean Abies (Pinaceae)

The eastern‐Mediterranean Abies taxa, which include both widely distributed species and taxa with minuscule ranges, represent a good model to study the impacts of range size and fragmentation on the levels of genetic diversity and differentiation. To assess the patterns of genetic diversity and phylogenetic relationships among eastern‐Mediterranean Abies taxa, genetic variation was assessed by eight nuclear microsatellite loci in 52 populations of Abies taxa with a focus on those distributed in Turkey and the Caucasus. Both at the population and the taxon level, the subspecies or regional populations of Abies nordmanniana s.l. exhibited generally higher allelic richness, private allelic richness, and expected heterozygosity compared with Abies cilicica s.l. Results of both the Structure analysis and distance‐based approaches showed a strong differentiation of the two A. cilicica subspecies from the rest as well as from each other, whereas the subspecies of A. nordmanniana were distinct but less differentiated. ABC simulations were run for a set of scenarios of phylogeny and past demographic changes. For A. ×olcayana, the simulation gave a poor support for the hypothesis of being a taxon resulting from a past hybridization, the same is true for Abies equi‐trojani: both they represent evolutionary branches of Abies bornmuelleriana.     

Comparative phylogeographies of six species of hinged terrapins (Pelusios spp.) reveal discordant patterns and unexpected differentiation in the P. castaneus/P. chapini complex and P. rhodesianus

Using up to 2117 bp of mitochondrial DNA and up to 2012 bp of nuclear DNA, we analysed phylogeographic differentiation of six widely distributed species of African hinged terrapins (Pelusios spp.) representing different habitat types. Two taxa each live in savannahs or in forests and mesic savannahs, respectively, and the remaining two species occur in intermediate habitats. The species living in forests and mesic savannahs do not enter dry savannahs, whereas the savannah species may occur in dry and wet savannahs and even in semi‐arid steppe regions. We found no obvious correlation between habitat type and phylogeographic pattern: one savannah species (P. rhodesianus) shows phylogeographic structure, i.e. pronounced genetic differences among geographically distinct populations, and the other (P. nanus) not. One species inhabiting forests and mesic savannahs (P. carinatus) has phylogeographic structure, the other (P. gabonensis) not. The same pattern is true for the two ecologically intermediate species, with phylogeographic structure present in P. castaneus and absent in P. chapini. Nuclear evidence suggests that the latter two taxa with abutting and partially overlapping ranges are distinct, while mtDNA is only weakly differentiated. Pelusios castaneus shows pronounced phylogeographic structure, which could reflect Pleistocene range interruptions correlated with the fluctuating forest cover in West and Central Africa. Our results do not support the recognition of an extinct subspecies of P. castaneus for the Seychelles. Pelusios carinatus contains two well supported clades, which are separated by the Congo River. This species is closely related to P. rhodesianus, a taxon consisting of two deeply divergent mitochondrial clades. One of these clades is paraphyletic with respect to P. carinatus, but the two clades of P. rhodesianus are not differentiated in the studied nuclear markers and, again, paraphyletic with respect to P. carinatus. Using mtDNA sequences from the type material of P. rhodesianus, we were able to allocate this name to one of the two clades. However, owing to the confusing relationships of P. rhodesianus and P. carinatus, we refrain from taxonomic decisions.     

Inferring the roles of vicariance,climate and topography in population differentiation in Salamandra algira (Caudata,Salamandridae)

Integrating information from species occurrence data, environmental variables and molecular markers can provide valuable insights about the processes of population persistence and differentiation. In this study, we present the most comprehensive overview of the evolutionary history of the North African salamander Salamandra algira (Caudata, Salamandridae) to date, including analyses of climatic and topographical variables, and sequences of two mitochondrial and two nuclear DNA fragments, with a special focus on Algerian populations, under‐represented in previous studies. Coalescent‐based phylogenetic analyses of mtDNA data recover four well‐supported population groups corresponding to described subspecies, with a western clade including populations in north‐western Morocco (with two subclades corresponding to the subspecies tingitana and splendens), and an eastern clade including populations from north‐eastern Morocco (subspecies spelaea) and Algeria (subspecies algira). Inferred split times between major clades date back to the Miocene, with additional splits within each major clade in the Plio‐Pleistocene. Present climatic (aridity) and topographical factors account for geographical discontinuities across population groups and help identify potential areas of secondary contact between clades corresponding to the subspecies tingitana and splendens in the Rif mountains in Morocco. Niche analysis indicates the absence of phylogenetic signal in the use of environmental space in this species.     

Welcome back Janolidae and Antiopella: Improving the understanding of Janolidae and Madrellidae (Cladobranchia,Heterobranchia) with description of four new species

Proctonotidae and Madrellidae are families that belong to the suborder Cladobranchia. Historically, both have been the subjects of taxonomic confusion. Thus, Proctonotidae Gray, 1853, was subsequently named as Zephyrinidae Iredale and O'Donoghue, 1923 and Janolidae Pruvot‐Fol, 1933, but currently both are considered as synonyms of Proctonotidae. On the other hand, Alder and Hancock (1864) erected the genus Madrella in Proctonotidae. Here, we completed a detailed morphological and molecular study of four apparently undescribed species of Madrellidae and Proctonotidae from the Indo‐Pacific. We performed a maximum likelihood and Bayesian inference phylogenetic analyses using two mitochondrial and one nuclear genes to improve the understanding of the families. Prompted by our results, Janolidae is removed from synonymy with Proctonotidae. Within Janolidae, there are two well‐supported clades. One includes species with smooth cerata that are found in the Atlantic and eastern Pacific Oceans. The taxa in this clade include the type species of Antiopella and several other species. We resurrect Antiopella as the valid name for this clade. The sister clade to Antiopella includes a variety of taxa with species that have been traditionally included in Janolus Bergh, 1884 and Bonisa Gosliner, 1981. Further systematic revision requires more comprehensive taxon sampling. The new species discovered have clear morphological differences and strong molecular support. They include Madrella amphora Pola and Gosliner sp. nov. , Janolus tricellariodes Pola and Gosliner sp. nov. , Janolus flavoanulatus Pola and Gosliner sp. nov., and Janolus incrustans Pola and Gosliner sp. nov.     

Ecological niche comparison and molecular phylogeny segregate the invasive moss species Campylopus introflexus (Leucobryaceae,Bryophyta) from its closest relatives

The delimitation of the invasive moss species Campylopus introflexus from its closest relative, Campylopus pilifer, has been long debated based on morphology. Previous molecular phylogenetic reconstructions based on the nuclear ribosomal internal transcribed spacers (ITS) 1 and 2 showed that C. pilifer is split into an Old World and a New World lineage, but remained partly inconclusive concerning the relationships between these two clades and C. introflexus. Analyses of an extended ITS dataset displayed statistically supported incongruence between ITS1 and ITS2. ITS1 separates the New World clade of C. pilifer from a clade comprising C. introflexus and the Old World C. pilifer. Ancestral state reconstruction showed that this topology is morphologically supported by differences in the height of the dorsal costal lamellae in leaf cross‐section (despite some overlap). ITS2, in contrast, supports the current morphological species concept, i.e., separating C. introflexus from C. pilifer, which is morphologically supported by the orientation of the hyaline hair point at leaf apex as well as costal lamellae height. Re‐analysis of published and newly generated plastid atpB‐rbcL spacer sequences supported the three ITS lineages. Ecological niche modeling proved a useful approach and showed that all three molecular lineages occupy distinct environmental spaces that are similar, but undoubtedly not equivalent. In line with the ITS1 topology, the C. pilifer lineage from the New World occupies the most distinct environmental niche, whereas the niches of Old World C. pilifer and C. introflexus are very similar. Taking the inferences from ecological niche comparisons, phylogenetics, and morphology together, we conclude that all three molecular lineages represent different taxa that should be recognized as independent species, viz. C. introflexus, C. pilifer (Old World clade), and the reinstated C. lamellatus Mont. (New World clade).     

Molecular and morphological criteria for revision of the genus Microcoleus (Oscillatoriales,Cyanobacteria)

Ninety‐two strains of Microcoleus vaginatus (=nomenclatural‐type species of the genus Microcoleus Desmazières ex Gomont) and Phormidium autumnale Trevisan ex Gomont from a wide diversity of regions and biotopes were examined using a combination of morphological and molecular methods. Phylogenies based on the 16S rDNA and 16S‐23S ITS (partial) demonstrated that the 92 strains, together with a number of strains in GenBank, were members of a highly supported monophyletic clade of strains (Bayesian posterior probability = 1.0) distant from the species‐cluster containing the generitype of Phormidium. Similarity of the 16S rRNA gene exceeded 95.5% among all members of the Microcoleus clade, but was less than 95% between any Microcoleus strains and species outside of the clade (e.g., Phormidium sensu stricto). These findings, which are in agreement with earlier studies on these taxa, necessitate the revision of Microcoleus to include P. autumnale. Furthermore, the cluster of Phormidium species in the P. autumnale group (known as Group VII) must be moved into Microcoleus as well, and these nomenclatural transfers are included in this study. The main diacritical characters defining Microcoleus are related to the cytomorphology of trichomes, including: narrowed trichome ends, calyptra, cells shorter than wide up to more or less isodiametric, and facultative presence of sheaths. The majority of species are 4–10 μm in diameter. The possession of multiple trichomes in a common sheath is present facultatively in many but not all species.     

DNA barcoding provides support for a cryptic species complex within the globally distributed and fishery important opah (Lampris guttatus)

The cornerstone of fisheries management relies on a solid taxonomic base and an understanding of how animals can be grouped into coherent management units. Surprisingly, little is known about the basic biology and ecology of opah (Lampris guttatus), a globally distributed species that is commercially exploited and regionally common in the North Pacific. Recent efforts to collect life history data on this species uncovered evidence of two North Pacific morphotypes. Sequencing of the mitochondrial cytochrome c oxidase I gene (655 bp) for these morphotypes and other specimens collected worldwide (n = 480) produced five strongly diverged and well‐supported clades. Additional sequence data from the cytochrome b gene (1141 bp) as well as the nuclear recombination activating gene 1 (1323 bp) corroborated these results, suggesting these five clades probably represent separate species. Our conclusion that opah is a complex of five separate species has implications for management and indicates a need to gather additional data on these poorly understood fishes.     

Taxonomy of cryptic species in the Cyornis rubeculoides complex in the Indian subcontinent

Taxa classified as subspecies may in fact be cryptic species. We assessed the taxonomic status of the Blue-throated Flycatcher Cyornis rubeculoides complex in India, which consists of several forms with similar plumages and song. We used mitochondrial and nuclear DNA, plumage traits, and detailed song analysis to ascertain the taxonomic status of the different forms. The molecular data identified three primary clades: (1) in the west Himalayan foothills, (2) at higher elevations in the northeast hill states of Meghalaya, Nagaland and Mizoram, and (3) at lower elevations in the northeastern hills of Meghalaya and the east Himalayas of Arunachal Pradesh. The western clade represents nominate C. rubeculoides rubeculoides. The high-elevation eastern clade was considered to be C. rubeculoides rogersi, because it included a sample from this subspecies from near the type locality in southwest Myanmar. These two sister clades had an estimated divergence time of 1.5 million years (my). The low-elevation east clade has previously been assigned to C. rubeculoides, but we showed it is closely related to the Hainan Blue Flycatcher Cyornis hainanus, formerly thought to breed only further east, with an estimated divergence time of only ~0.8 my. This clade may represent a subspecies of C. hainanus or, given reports of widespread sympatry with C. hainanus in Thailand, a distinct species, Cyornis dialilaemus. However, more research is advocated, including molecular data, from the area of overlap. Songs were remarkably similar across all taxa. In playback experiments, C. r. rubeculoides in the west responded to all taxa. This is in agreement with recent work demonstrating that song differences and responses to songs are not always a good indicator of the progress of reproductive isolation.     

Phylogenetic relationships in the Sceloporus variabilis (Squamata: Phrynosomatidae) complex based on three molecular markers,continuous characters and geometric morphometric data

The monophyly of the Sceloporus variabilis group is well established with five species and two species complexes, but phylogenetic relationships within species complexes are still uncertain. We studied 278 specimens in 20 terminals to sample all taxa in the “variabilis group,” including three subspecies in the “variabilis complex,” and two outgroups (Sceloporus grammicus and Sceloporus megalepidurus). We assembled an extensive morphological data set with discrete and continuous characters (distances and scale counts), including geometric morphometric data (landmark coordinates of three shapes), and a three‐marker molecular data set as well (ND4, 12S and RAG1). We conducted parsimony and Bayesian phylogenetic inferences on these data, including several partitioning and weighting schemes. We suggest elevating three subspecies to full species status. Therefore, we recommend recognition of nine species in the “variabilis group.” First, S. variabilis is sister to Sceloporus teapensis. In turn, Sceloporus cozumelae is sister to Sceloporus olloporus. These four species are a monophyletic group, which is sister to Sceloporus smithi. Finally, Sceloporus marmoratus is sister of the clade of five species. The other species in the “variabilis group” (Sceloporus chrysostictus, Sceloporus couchii and Sceloporus parvus) are a paraphyletic grade at the base of the tree. Our analyses reject the existence of the “variabilis complex.” We conducted a parsimony‐based ancestral reconstruction on body size (snout–vent length), femoral pores and dorsal scales and related morphological changes to geographic distribution of the species. Our phylogenetic hypothesis will allow best designs of comparative studies with species in the “variabilis group,” one of the earliest divergent lineages in the genus.     

Examination of prezygotic and postzygotic isolating barriers in tropical Ulva (Ulvophyceae,Chlorophyta): evidence for ongoing speciation

Phylogenetic clades based on DNA sequences such as the chloroplast rbcL gene and the nuclear ITS region are frequently used to delimit algal species. However, these molecular markers cannot accurately delimit boundaries among some Ulva species. Although Ulva reticulata and Ulva ohnoi occasionally bloom in tropical to warm‐temperate regions and are clearly distinguishable by their reticulate or plain blade morphology, they have few or no sequence divergences in these molecular markers and form a monophyletic clade. In this study, to clarify the speciation and species delimitation in the U. reticulata‐ohnoi complex clade, reproductive relationships among several sexual strains from the Philippines and Japan including offspring that originated from the type specimen of U. ohnoi were examined by culturing and hybridization in addition to the ITS‐based analysis. As a result, both prezygotic and postzygotic reproductive isolation were revealed to occur between genetically perforated U. reticulata and imperforate U. ohnoi. They were also separated on the basis of sequence analysis of the ITS region. That strongly supports that the two taxa are independent biological species. Although no prezygotic barrier among the Philippine and Japanese strains of U. reticulata was observed, unexpectedly zoospores produced by hybrid sporophytes in some of their combinations mostly failed to develop, indicating partial formation of a postzygotic barrier despite a 0.2% divergence in the ITS sequence. These findings suggest speciation is still ongoing in U. reticulata.     

Glass in the water: Molecular phylogenetics and evolution of Indian glassy perchlets (Teleostei: Ambassidae)

Glassfishes of the family Ambassidae, comprising around 50 species, are distributed in the Indo‐West Pacific where they inhabit marine, estuarine, and freshwater ecosystems. We investigated for the first time the molecular phylogenetic and evolutionary relationships of this group using a combined dataset of mitochondrial and nuclear genes, particularly focusing on the taxa occurring in the Indian subcontinent. Results revealed that marine and freshwater genera of Ambassidae diverged during the Paleocene (~62 mya). The enigmatic monotypic genus Chanda is nested within the larger clade currently recognized as Parambassis, indicating its paraphyly. Based on cleared and stained osteological preparations and phylogenetic placement of Chanda nama, we hypothesize that the elongated and protruding lower jaw is an autapomorphic character that might have evolved for the lepidophagous habit of the species. The southern Indian species of Parambassis, Parambassis dayi, and Parambassis thomassi, which formed a monophyletic group, probably diverged from other species of Parambassis and Chanda nama around the Eocene (~42 mya) and can potentially be recognized as a distinct genus in view of the apomorphic characters such as the presence of serration on the ventral fringe of interopercle, densely serrated palatine and ectopterygoid, and the presence of more than 30 serrations along the lower preopercle and the posterior edge. Our analysis provides new insights into the evolution and phylogenetic relationships of glassy perchlets, including detailed relationships among the Indian species within this family.     

Finding arboreal snakes in an evolutionary tree: phylogenetic placement and systematic revision of the Neotropical birdsnakes

The genus Pseustes Fitzinger, 1843 is composed of three recognized species, Pseustes poecilonotus, P. shropshirei and P. sulphureus, which may be the largest sized colubrid snake in the New World. The group has a complex systematic history that has yet to be untangled using modern molecular phylogenetic approaches. The systematic position, within‐group diversity and distribution are therefore uncertain. We obtained samples of four species from multiple specimens across their distribution and analysed one nuclear and two mitochondrial genes to determine the phylogenetic placement of the genus and infer relationships among Pseustes lineages. We find strong support for the paraphyly of Pseustes with respect to the monotypic genus Spilotes, both of which are nested within a clade of at least 23 other New World Colubrinae genera. Based on our results, we formally revise the taxonomy of P. poecilonotus and P. sulphureus, resurrecting the taxon P. polylepis for populations of P. poecilonotus from South America and allocating P. sulphureus to the genus Spilotes which renders both genera monophyletic. Additionally, we identify two lineages that are putatively new and currently unrecognized species. Finally, the placement of P. sulphureus, the type species of Pseustes, in the genus Spilotes, requires the allocation of the senior synonym Phrynonax be considered for the remaining Pseustes taxa.     

Reversing expansion of Calamagrostis epigejos in a grassland biodiversity hotspot: Hemiparasitic Rhinanthus major does a better job than increased mowing intensity

Questions

Can hemiparasitic Rhinanthus major originating from a local population suppress the competitive clonal grass Calamagrostis epigejos and reverse its expansion in species‐rich semi‐natural grasslands? Does sowing seeds of R. major facilitate restoration of target meadow vegetation? Is R. major more beneficial for biodiversity restoration/conservation than increased mowing intensity, a conventional measure to suppress C. epigejos?

Location

?ertoryje National Nature Reserve, Bílé Karpaty (White Carpathians) Protected Landscape Area, Czech Republic.

Methods

We conducted a before‐after‐control‐impact experiment in meadow patches heavily infested by C. epigejos: eight blocks, each containing four plots with four treatment combinations: (1) traditional management, i.e. mowing once in summer, (2) mowing in summer and autumn (3) mowing in summer and seed sowing of R. major, (4) mowing in summer and autumn and seed sowing of R. major. Above‐ground biomass of C. epigejos and vegetation composition of each of the plots were monitored every year from 2013 to 2016. To assess the effects of treatments, we analysed biomass production of C. epigejos, herb layer cover and vegetation composition.

Results

Both sowing R. major and an additional autumn meadow cut significantly suppressed C. epigejos. Their effects were additive and of comparable size. Both treatments also had significant but markedly different effects on community composition. Rhinanthus major facilitated directional community composition change towards the regional Brachypodio‐Molinetum meadows. In contrast, increased mowing intensity significantly decreased frequency of threatened species, which however may have also been influenced by R. major.

Conclusions

Sowing of autochthonous R. major seeds was demonstrated as an efficient tool to suppress C. epigejos and facilitate community restoration. It can be combined with an additional meadow cut to further accelerate decline of the grass. The additional cut should however be used as a short‐term practice (1–2 years) only to minimize potential negative effects of its long‐term application on some threatened plant species. The effects of R. major are comparable to those of Rhinanthus alectorolophus reported previously. As a species occurring naturally in species‐rich dry grasslands, R. major has a broader and longer‐term application potential than R. alectorolophus in ecological restoration and conservation of these communities.