Disjunct Geographical Distribution Research Articles

Recurrent gene flow events occurred during the diversification of clownfishes of the skunk complex.

Clownfish (subfamily Amphiprioninae) are an iconic group of coral reef fish that evolved a mutualistic interaction with sea anemones, which triggered the adaptive radiation of the clade. Within clownfishes, the "skunk complex" is particularly interesting. Besides ecological speciation, interspecific gene flow and hybrid speciation are thought to have shaped the evolution of the group. We investigated the mechanisms characterizing the diversification of this complex. By taking advantage of their disjunct geographical distribution, we obtained whole-genome data of sympatric and allopatric populations of the three main species of the complex (Amphiprion akallopisos, A. perideraion and A. sandaracinos). We examined population structure, genomic divergence and introgression signals and performed demographic modelling to identify the most realistic diversification scenario. We excluded scenarios of strict isolation or hybrid origin of A. sandaracinos. We discovered moderate gene flow from A. perideraion to the ancestor of A. akallopisos + A. sandaracinos and weak gene flow between the species in the Indo-Australian Archipelago throughout the diversification of the group. We identified introgressed regions in A. sandaracinos and detected in A. perideraion two large regions of high divergence from the two other species. While we found that gene flow has occurred throughout the species' diversification, we also observed that recent admixture was less pervasive than initially thought, suggesting a role of host repartition or behavioural barriers in maintaining the genetic identity of the species in sympatry.

A new characid species with remarkable sexual dimorphism (Characiformes: Characidae: Stevardiinae) from the upper Guayabero River, Orinoco basin, Colombia.

A new species of characid with remarkable sexual characteristics is described from the upper Guayabero River drainage from the Orinoco basin in Colombia. The new species is included in the genus Monotocheirodon by sharing most of the previously proposed diagnostic features of this genus. It differs from all Stevardiinae by the combination, in adult males, of an enlarged urogenital papilla in contact with the first anal-fin unbranched ray and a highly modified anal fin with enlarged and distally elongated first and second branched anal-fin rays, forming a gonopodium-like structure. In addition, it differs from congeners by the presence of an adipose fin, an incomplete lateral line, an ascending process of the premaxilla dorsally oriented, and a long snout. The new species was discovered from a poorly sampled region in Colombia and is an unexpected new record given its disjunct geographic distribution from other species of the genus. Monotocheirodon species were previously known from piedmont drainages in Bolivia and Peru. The conservation status of the new species is herein categorized following IUCN criteria.

Taxonomic revision of the native Magnolia (Magnoliaceae) species of Brazil.

The genus Magnolia (Magnoliaceae) has a wide and disjunct geographic distribution ranging from Eastern and South Asia to Malaysia, extending across the Neartics and reaching into the Neotropics. Regarding its infrageneric classification, the genus is divided into three subgenera: Yulania, Gynopodium and Magnolia, the latter including the section Talauma in which the native Brazilian taxa are classified. The species of Magnoliasect.Talauma can be recognized by two parallel longitudinal scars on the petiole formed by the shedding of the stipules, in addition to a woody syncarp that breaks into irregular plates at dehiscence. Currently, in Brazil, species recognition is not clear on national platforms that are widely used by the Brazilian botanical community (e.g. Flora do Brasil), with only two native Magnolia species being accepted: M.amazonica and M.ovata. The lack of knowledge about the species and their respective characteristics has resulted in many identification errors in Brazilian herbaria, which contributes to the lack of knowledge about their current conservation status. We conducted a complete taxonomic revision based on extensive fieldwork, a herbarium survey, along with literature study. Based on this, we propose to recognize three previously described species, supporting the acceptance of five native Magnolias occurring in Brazil, namely: M.amazonica, M.brasiliensis, M.irwiniana, M.ovata and M.sellowiana. However, we follow the Flora do Brasil in maintaining M.paranaensis as a synonym of M.ovata. Additionally, we designate a lectotype for M.sellowiana. We present morphological descriptions and the geographic distribution for each species, in addition to an identification key to all of these plus the two introduced ornamental species from Asia and North America, illustrations, photographs, ecological data, updated conservation status and taxonomic notes.

Phylogeography of Ara militaris (Military Macaw): Implications for Conservation

The Military Macaw (Ara militaris) is an endangered bird species with disjunct geographic distribution across the Neotropics, consisting of three recognized subspecies: One in Mexico (A. m. mexicanus) and two in South America (A. m. militaris and A. m. bolivianus). However, due to the limited phenotypic differentiation between these allopatric taxa, their taxonomic status has been the subject of debate. In this study, we explored mitochondrial DNA (mtDNA) variability to determine the phylogeographical pattern through phylogenetic and ecological modelling analyses. We also aimed to describe the evolutionary relationships of twelve A. militaris populations. We identified 41 haplotypes in the 300 bp region of the Cytochrome b (Cyt-b) gene of the mtDNA and low nucleotide diversity. The observed phylogeographic structure suggests the existence of two clades: One composed of A. m. militaris and A. m. bolivianus and another consisting solely of A. m. mexicanus. The A. m. mexicanus clade further divides into two recognized subclades: Sierra Madre Oriental and northeastern portion of the Sierra Madre Occidental. Ecological analyses revealed that the niche similarity between these lineages was lower than expected by chance. Additionally, results from low cross-prediction tests indicated that the two lineages have inhabited different environmental spaces since the Late Pleistocene. This divergence may be associated with a steep ecological gradient and contemporary geographical barrier. Based on our results, we suggest that at least the A. m. mexicanus has a divergent evolutionary history; therefore, it should be considered as a different evolutionarily significant and management unit. We recommend that future conservation strategies in Mexico incorporate effective protection measures, including habitat preservation and the reduction of illegal trade, to ensure the preservation of viable populations.

Phylogenetics of the Paleartic model grass Brachypodium sylvaticum uncovers two divergent oriental and occidental micro-taxa lineages

Brachypodium sylvaticum has been selected as a model for perennial grasses, and considerable genomic resources have been generated and a reference genome and several resequenced pangenome accessions are available for this species. Despite these genomic advances, the evolution and systematics of diploid B. sylvaticum s. l. is almost unknown. The B. sylvaticum complex is formed by up to seven taxonomically close micro-taxa which differentiate from typical B. sylvaticum s. s. based on a few morphological features. Moreover, some of them show some largely disjunct geographic distributions on both sides of their native Palearctic region. In this study, we used a phylogenomic approach including representative populations from the oriental and occidental distribution range of B. sylvaticum micro-taxa to elucidate their evolutionary relationships and assess the systematic value of the morphological features that separate them. A combined plastome and nuclear phylogenetic tree supports an early split and high divergence of the oriental lineage, showing the close relationship of the Himalayan B. sylvaticum var. breviglume lineages to the Pacific B. miserum / B. kurilense clade, and the contrasting large homogeneity and low divergence of the occidental European, N African and SW and C Asian lineage, with several B. sylvaticum s. s., B. spryginii, and B. glaucovirens samples showing identical or similar sequences. Divergence time estimate analysis suggests that the oriental lineage diverged from the common ancestor in the early Pleistocene (2.0 Ma), followed by subsequent colonization and isolations in the Himalayas (2.0 – 1.7 Ma) and the Far East (0.36 Ma) in more recent times, while the occidental lineage split in the Mid-Late Pleistocene (0.97 Ma), followed by rapid radiation and postglacial spread in the western Paleartic during the last thousand years.

Phylogeography and cryptic species structure of a locally adapted parasite in New Zealand.

The phylogeographic patterns of many taxa on New Zealand's South Island are characterized by disjunct distributions that have been attributed to Pleistocene climatic cycles and the formation of the Southern Alps. Pleistocene glaciation has been implicated in shaping the contemporary genetic differentiation between populations of the aquatic snail Potamopyrgus antipodarum. We investigated whether similar phylogeographic patterns exist for the snail's locally adapted trematode parasite, Atriophallophorus winterbourni. We found evidence for a barrier to gene‐flow in sympatry between cryptic, but ecologically divergent species. When focusing on the most common of these species, disjunct geographic distributions are found for mitochondrial lineages that diverged during the Pleistocene. The boundary between these distributions is found in the central part of the South Island and is reinforced by low cross‐alpine migration. Further support for a vicariant origin of the phylogeographic pattern was found when assessing nuclear multilocus SNP data. Nuclear and mitochondrial population differentiation was concordant in pattern, except for populations in a potential secondary contact zone. Additionally, we found larger than expected differentiation between nuclear‐ and mitochondrial‐based empirical Bayes F ST estimates (global F ST: 0.02 vs. 0.39 for nuclear and mitochondrial data, respectively). Population subdivision is theoretically expected to be stronger for mitochondrial genomes due to a smaller effective population size, but the strong difference here, together with mitonuclear discordance in a putative contact zone, is potentially indicative of divergent gene flow of nuclear and mitochondrial genomes.

A New Genus of Tachydromiinae from South Africa and Turkmenistan (Diptera: Empidoidea: Hybotidae).

Simple SummaryA new hybotid dance fly (or fast-running fly) genus, Parallelodromia is described along with three new species. The new genus is recorded from South Africa and Turkmenistan. Details are provided regarding the morphology of the flies and the wide geographical gap between the species is discussed.Parallelodromia gen. nov. is described with the inclusion of two new species from South Africa (P. glenlyonensis sp. nov. and P. hantamica sp. nov.) and a new species (P. turkmenistanica sp. nov.) from Turkmenistan. The genus is fully illustrated along with a discussion of its unusual disjunct geographic distribution and its phylogenetic relationship within the Tachydromiinae tribe Drapetidini.

Brachiopods in early Mesozoic cryptic habitats: Continuous colonization, rapid adaptation, and wide geographic distribution

Late Triassic and early Jurassic dikes and fissures in the Dachstein Limestone in the Northern Calcareous Alps harbor mass occurrences of the rhynchonellide brachiopods Sulcirostra juvavica and Halorella amphitoma . To test recent hypotheses about their paleoecology, we characterized these habitats using petrography, carbon stable isotopes, and trace element patterns, and found no evidence for hydrocarbon seepage or hydrothermal venting. Thus the brachiopods lived under normal-marine conditions, in darkness and absence of local photosynthetic primary production, hence relying on the supply of limited and presumably small-sized food washed into the dikes and fissures. Because Halorella and Sulcirostra occur in dikes and fissures since the beginning of their stratigraphic ranges, these rhynchonellides are not relics of formerly widely distributed taxa, but instead are two genera that rapidly adapted to these habitats. Both Halorella and Sulcirostra occur also in late Triassic and early Jurassic deep-water settings such as deep-marine sills and hydrocarbon seeps, indicating that close phylogenetic relationships between submarine cave faunas and deep-sea faunas, as seen today, existed also in the early Mesozoic, albeit among very different taxa. Another analogy to the modern cave fauna is the wide but disjunct geographic distribution of Sulcirostra and Halorella , both found throughout the Tethys and Panthalassa oceans. Our findings support the view that submarine cave habitats were continuously colonized by new taxa throughout Earth's history.

Similar pattern, different paths: tracing the biogeographical history of Megaloptera (Insecta: Neuropterida) using mitochondrial phylogenomics.

The sequential breakup of the supercontinent Pangaea since the Middle Jurassic is one of the crucial factors that has driven the biogeographical patterns of terrestrial biotas. Despite decades of effort searching for concordant patterns between diversification and continental fragmentation among taxonomic groups, increasing evidence has revealed more complex and idiosyncratic scenarios resulting from a mixture of vicariance, dispersal and extinction. Aquatic insects with discreet ecological requirements, low vagility and disjunct distributions represent a valuable model for testing biogeographical hypotheses by reconstructing their distribution patterns and temporal divergences. Insects of the order Megaloptera have exclusively aquatic larvae, their adults have low vagility, and the group has a highly disjunct geographical distribution. Here we present a comprehensive phylogeny of Megaloptera based on a large-scale mitochondrial genome sequencing of 99 species representing >90% of the world genera from all major biogeographical regions. Molecular dating suggests that the deep divergence within Megaloptera pre-dates the breakup of Pangaea. Subsequently, the intergeneric divergences within Corydalinae (dobsonflies), Chauliodinae (fishflies) and Sialidae (alderflies) might have been driven by both vicariance and dispersal correlated with the shifting continent during the Cretaceous, but with strikingly different and incongruent biogeographical signals. The austral distribution of many corydalids appears to be a result of colonization from Eurasia through southward dispersal across Europe and Africa during the Cretaceous, whereas a nearly contemporaneous dispersal via northward rafting of Gondwanan landmasses may account for the colonization of extant Eurasian alderflies from the south.

A dated molecular phylogeny and biogeographical analysis reveals the evolutionary history of the trans-pacifically disjunct tropical tree genus Ormosia (Fabaceae)

The papilionoid legume genus Ormosia (Fabaceae) comprises about 150 species of trees and exhibits a striking disjunct geographical distribution between the New World- and Asian and Australasian wet tropics and subtropics. Modern classifications of Ormosia are not grounded on a well-substantiated phylogenetic hypothesis and have been limited to just portions of the geographical range of the genus. The lack of an evolutionarily-based foundation for systematic studies has hindered taxonomic work on the genus and prevented the testing of biogeographical hypotheses related to the origin of the Old World/New World disjunction and the individual dispersal histories within both areas. Here, we present the most comprehensively sampled molecular phylogeny of Ormosia to date, based on analysis of both nuclear (ITS) and plastid (matK and trnL–F) DNA sequences from 82 species of the genus. Phylogenetically-based divergence times and ancestral range estimations are employed to test hypotheses related to the biogeographical history of the genus. We find strong support for the monophyly of Ormosia and the grouping of all sampled Asian species of the genus into two comparably sized clades, one of which is sister to another large clade containing all sampled New World species. Within the New World clade, additional resolution supports the grouping of most species into three mutually exclusive subordinate clades. The remaining New World species form a fourth well-supported clade in the analyses of plastid sequences, but that result is contradicted by the analysis of ITS. With few exceptions the supported clades have not been previously recognized as taxonomic groups. The biogeographical analysis suggests that Ormosia originated in continental Asia and dispersed to the New World in the Oligocene or early Miocene via long-distance trans-oceanic dispersal. We reject the hypothesis that the inter-hemispheric disjunction in Ormosia resulted from fragmentation of a more continuous “Boreotropical” distribution since the dispersal post-dates Eocene climatic maxima. Both of the Old World clades appear to have originated in mainland Asia and subsequently dispersed into the Malay Archipelago and beyond, at least two lineages dispersing across Wallace’s Line as far as the Solomon Islands and northeastern Australia. In the New World, the major clades all originated in Amazonia. Dispersal from Amazonia into peripheral areas in Central America, the Caribbean, and Extra-Amazonian Brazil occurred multiple times over varying time scales, the earliest beginning in the late Miocene. In a few cases, these dispersals were followed by local diversification, but not by reverse migration back to Amazonia. Within each of the two main areas of distribution, multiple modest bouts of oceanic dispersal were required to achieve the modern distributions.

The role of vicariance and dispersal on the temporal range dynamics of forest vipers in the Neotropical region.

The emergence of the diagonal of open/dry vegetations, including Chaco, Cerrado and Caatinga, is suggested to have acted as a dispersal barrier for terrestrial organisms by fragmenting a single large forest that existed in South America into the present Atlantic and Amazon forests. Here we tested the hypothesis that the expansion of the South American diagonal of open/dry landscapes acted as a vicariant process for forest lanceheads of the genus Bothrops, by analyzing the temporal range dynamics of those snakes. We estimated ancestral geographic ranges of the focal lancehead clade and its sister clade using a Bayesian dated phylogeny and the BioGeoBEARS package. We compared nine Maximum Likelihood models to infer ancestral range probabilities and their related biogeographic processes. The best fitting models (DECTS and DIVALIKETS) recovered the ancestor of our focal clade in the Amazon biogeographic region of northwestern South America. Vicariant processes in two different subclades resulted in disjunct geographic distributions in the Amazon and the Atlantic Forest. Dispersal processes must have occurred mostly within the Amazon and the Atlantic Forest and not between them. Our results suggest the fragmentation of a single ancient large forest into the Atlantic and Amazon forests acting as a driver of vicariant processes for the snake lineage studied, highlighting the importance of the diagonal of open/dry landscapes in shaping distribution patterns of terrestrial biota in South America.

Molecular Phylogeny, Character Evolution, and Biogeography of Hydrangea Section Cornidia, Hydrangeaceae.

Background: Hydrangea section Cornidia consists of 26 currently accepted species and a yet undefined number of new species and erroneously synonymized taxa. This clade consists of (sub)tropical lianas occurring from northern Mexico to southern Chile and Argentina, and one species from Southeast Asia. Currently, no molecular phylogenetic hypothesis is available that includes more than a few species of this section. Hence, a resolved and well-sampled molecular phylogenetic hypothesis may help to enforce taxonomic decisions. In this study, we present a phylogenetic framework based on sequences from two low copy nuclear genes from a comprehensive taxon sampling of H. section Cornidia and a selection of outgroups. Our phylogenetic reconstructions prove the non-monophyly of the traditionally recognized subsections Monosegia and Polysegia and their corresponding series, Speciosae and Aphananthae, and Synstyleae and Chorystyleae, respectively. Three morphologically defined species were recovered with high support as monophyletic, namely, Hydrangea panamensis, Hydrangea serratifolia, and Hydrangea tarapotensis. However, statistical support for some shallow nodes did not allow to refute, with high support, the monophyly of several of the herein recognized species for which more than one individual could be analyzed. Based on the obtained phylogenetic framework, we reconstructed the evolution of selected reproductive characters. Hydrangea section Cornidia is the only genus section for which dioecism has been extensively documented. Our character reconstruction of sexual dimorphism shows that dioecism is the ancestral state in this section and that this was reversed to monoecy in Hydrangea seemannii and Hydrangea integrifolia. Character reconstruction for the enlarged marginal flowers recovered their presence as the ancestral character state in H. section Cornidia, although at least three internal lineages independently lost them; thus, losses were reconstructed to be more likely than gain. With respect to the flower color, more species exhibit white than red flowers, and white is reconstructed as the ancestral state. Cornidia also shows an unusual disjunct geographic distribution between Asia and Central Mesoamerica—South America, as it is not present in the USA and Canada. The origin of Cornidia is reconstructed to be the New World with higher probability, and the presence of one species in Asia is likely due to long-distance dispersal.

A new species of Sun Skink (Reptilia: Scincidae: Eutropis) from the Zamboanga Peninsula, southwestern Mindanao Island, Philippines

We describe a new species of lizard in the genus Eutropis Fitzinger 1843 from the southwestern tip of the Zamboanga Peninsula on the western part of Mindanao Island, Philippines. The new species is related to Eutropis rugifera, which is a secretive, forest-adapted skink that ranges widely outside the Philippines from the western extent of its distribution on Nicobar Island (the type locality) through southern Peninsular Malaysia, Sumatra, and the Mentawai islands, Borneo, Java, and as far east as Bali Island. The discovery of a new, morphologically distinct, and genetically highly divergent Sun Skink lineage in the low elevation forests of the Zamboanga Peninsula creates a puzzling disjunct geographic distribution (E. rugifera has not been reported from the Sulu Archipelago). The new species is estimated to have diverged ~10–16 mya from E. rugifera, from which it appears to have an extralimital and isolated distribution. Considering the dynamic geological history and ancient continental origin of the Zamboanga Peninsula, colonization by the new species may have been facilitated by pre-Pleistocene overseas long-distance dispersal, saltatory range expansion, and subsequent contraction/extinction in the Sulu Archipelago, and/or possibly paleotransport on the ancient crustal fragment of Zamboanga. The new species is known only from Zamboanga City’s primary surface water supply catchment at the lowest elevations inside the boundaries of Pasonanca Natural Park, despite the fact that there have been historical surveys of herpetological diversity at multiple sites to the northeast (Zamboanga, western Mindanao) and to the southwest (Sulu Archipelago). The new species, thus, may be limited to just the tip of the Zamboanga Peninsula, possibly rendering KEYWORDS: IUCN Red List, Palawan microcontinent block, Pasonanca Natural Park, Sulu Archipelago, Surface catchment watershed biodiversity

Phylogenetics of Piresia (Poaceae: Bambusoideae) reveals unexpected generic relationships within Olyreae with taxonomic and biogeographic implications

AbstractPiresia, a Neotropical herbaceous bamboo genus (Poaceae, Olyreae) including six described species, has a disjunct geographic distribution involving the Caribbean and north/western South America and the northeastern Atlantic Forest in Brazil. Its phylogenetic relationships are poorly known, especially with respect to certain monotypic genera within Olyrinae, such as Reitzia, endemic to the Atlantic forest of southern/south Brazil, and Piresiella, endemic to Cuba. In order to examine the evolutionary history of Piresia, we analyzed 36 samples, including known and possible new species of the genus, as well as members of Reitzia, Piresiella and other genera of subtribes Olyrinae, Parianinae and Buergersiochloinae as the ingroup, and selected woody bamboos and Lolium (Pooideae) as the outgroups. Five regions of plastid and nuclear non‐coding DNA spacers (trnD‐trnT, trnS‐trnG, rpl32‐trnL, trnH‐psbA, ITS) were sequenced, and to estimate phylogenetic relationships, we used Bayesian inference, maximum likelihood and maximum parsimony considering the plastid regions (with and without gaps) and ITS separately. Surprisingly, Piresiella emerged as sister to the monotypic Buergersiochloa (Buergersiochloinae), endemic to New Guinea. Based on these results and morphological analysis, we discuss the implications for the biogeography of the herbaceous bamboos, formally transfer Ekmanochloa, Mniochloa and Piresiella to Buergersiochloinae, and provide an emended description of the subtribe. Three main lineages were recovered within Olyrinae, one of them comprising Piresia and Reitzia, with high support. Within this clade, the two main lineages are geographically distinct, and their evolutionary history seems to be complex and possibly related to adaptations to climatic conditions. We suggest new directions for future studies involving this clade, in order to better understand its evolutionary history and generic circumscription.

Skipping the Dry Diagonal: spatio-temporal evolution ofCrotonsectionCleodora(Euphorbiaceae) in the Neotropics

AbstractCroton is one of the largest angiosperm genera, with > 1200 species in the tropics worldwide. The arborescent Croton section Cleodora stands out for its disjunct geographical distribution with two main centres of diversity in the Amazonian and Atlantic Forest regions, separated by the Caatinga, Cerrado and Chaco biomes (the ‘Dry Diagonal’). This disjunction is found in other Neotropical lineages and attributed to Neogene geological and climatic events. We inferred a nearly complete phylogenetic reconstruction of Croton section Cleodora based on DNA sequences of nuclear ITS and five plastid regions (rps16, trnH-psbA, trnL-F, trnT-L and ycf1). We further estimated divergence times and reconstructed ancestral ranges using Bayesian methods. Our results show that Croton section Cleodora is monophyletic with two main clades; we also confirm the phylogenetic adscription of eight Croton spp. recently described or assigned to section Cleodora based on morphology. Divergence of section Cleodora from its sister clade occurred c. 25 Mya, and diversification within this group started 20 Mya. Biogeographic analyses suggest the section originated in the Amazonian region, from where it dispersed to other forested Neotropical regions, including the Atlantic Forest. Divergence between Amazonian and Atlantic Forest taxa appears to have been triggered by the formation of the South American Dry Diagonal.

<p><strong><em>Matelea ojadapantha </em></strong><strong>(Apocynaceae; Asclepiadoideae; Gonolobeae; Gonolobinae), a new species from México</strong></p>

A new species of Matelea from central and southern México with green to black corollas and pubescent lobes is described here: Matelea ojadapantha. This taxon is morphologically similar to M. schaffneri and M. atrostellata but differs by the corolla and corona morphology and has a disjunct geographic distribution. Descriptions, illustrations, morphological comparisons, map of the distributions of this species as well as their conservation status is provided. This discovery highlights México as a center of diversity of the genus, as more than 70 species are currently known in the country. Furthermore, 60% of those species are endemic.

Testing species hypotheses in the mangrove genus Rhizophora from the Western hemisphere and South Pacific islands

The determination of species limits is key to biology, with practical implications for conservation policy makers, lawyers and stakeholders. However, naming species may be a difficult task as interspecific hybridization blurs species boundaries. Natural interspecific gene flow has been reported for seven distinct mangrove genera, including the iconic genus Rhizophora. Species limits within this genus have long been debated because of morphological similarity, natural variability in diagnostic traits, disjunct geographic distribution, and recent molecular data have reignited this issue. Here, we used a phylogeographical approach based on genome-wide single nucleotide polymorphism (SNP) data to test species hypotheses of R. mangle, R. racemosa and R. X harrisonii from the Atlantic East Pacific (AEP) biogeographic region and South Pacific islands. Genetic structure patterns and Approximate Bayesian Computation (ABC) analyses revealed that taxonomic identification based only on morphological traits could not predict genetic clustering alone nor the phylogenetic relationships among groups. The American continent plays an important role as a barrier to gene flow within the genus such that trees identified morphologically as R. racemosa from the Atlantic basin are more genetically similar to R. mangle from the same basin than to R. racemosa trees from the Pacific coast. Additionally, our findings supported previous studies that showed that R. samoensis is indistinguishable from R. mangle populations from the Pacific basin. Moreover, we provide novel evidence that R. X harrisonii is likely composed by two independently originated and separately maintained evolutionary lineages in both sides of the American continent. Our findings provide novel evidence of taxonomic inconsistency of current morphology-based species designations in Western hemisphere and South Pacific islands Rhizophora species.

Evolutionary history of the Eurasian steppe plant Schivereckia podolica (Brassicaceae) and its close relatives

The genus Schivereckia (Brassicaceae) – presently included in the genus Draba – comprises two species, S. podolica and S. doerfleri. Schivereckia podolica is an eastern European species with disjunct distribution in Russia, Ukraine, and Podolian-Galician outposts. Schivereckia doerfleri is reported from alpine fields of the Balkan Peninsula and from mountain chains of northern Anatolia, Turkey. Schivereckia podolica shares its ecological and biogeographic characteristics with a number of other steppe plants. The ‘relic hypothesis’ interprets the present locations of Schivereckia and its associates as relics of a formerly continuous distribution belt of a cold periglacial steppe vegetation.We employed nuclear ITS and chloroplast trnL-trnF region, and DNA fingerprinting (RAPD) to elucidate the evolutionary history and historical biogeography of Schivereckia. RAPD data prove isolation by distance and mirror the present disjunct geographical distribution pattern of Schivereckia podolica. Phylogenetic analyses revealed that Schivereckia might be polyphyletic and nested within a highly supported clade of central Asian, Caucasian and North American Draba species. Time divergence estimation and ancestral area reconstruction support the interpretation of species of the Schivereckia subclade as periglacial relic. Our results argue for a continuous persistence of certain steppe species since the Pleistocene, and support the view that the modern steppes of Europe have derived partly from Pleistocene glacial steppes.

Studies on the biogeography of Phellinotus piptadeniae (Hymenochaetales, Basidiomycota): Expanding the knowledge on its distribution and clarifying hosts relationships

Abstract Phellinotus piptadeniae is associated with several hosts and presents a continental and disjunct geographic distribution, whose populations occur in both dry and wet forests of South America. To understand the distribution of P. piptadeniae, we explored the prior knowledge of its host geography to predict potential distribution of the fungus and discuss aspects of its geography. Based on records from public herbarium data of Piptadenia gonoacantha, the main host of P. piptadeniae, we confirmed its occurrence in four Brazilian states with no previous records. Also, the analysis of herbarium specimens from Brazil and Argentina revealed the presence of P. piptadeniae in one additional Brazilian state and its first record in Argentina. Our study showed the importance of using prior information of host distribution to clarify the P. piptadeniae distribution pattern. The most representative host of the fungus was Pip. gonoacantha (1117 records). Further, a high environmental concordance between P. piptadeniae and a contemporary Seasonally Dry Tropical Forest distribution map (~76% of the records) was observed. We discuss the current distribution pattern of P. piptadeniae, present evidence for Caatinga as an ancestral area of the Phellinotus lineage and the Vanishing refuge model as the probable process that shapes the natural history of the species.

The cavernicolous swimming crab Atoportunus dolichopus Takeda, 2003 (Crustacea, Decapoda, Portunidae) reported for the first time in the Western Indian Ocean during technical dives in the mesophotic zone

The rare cavernicolous crab Atoportunus dolichopus Takeda, 2003, described from Kume-Jima Island, Ryukyu archipelago, is recorded for the first time since its description. Two pecimens were observed in a marine cave off Mayotte Island, Western Indian Ocean, during technical dives in the mesophotic zone. The crabs were observed in total darkness at a depth of 75m, 120m from the entrance of the cave. No specimens were collected but morphological traits recognized on close-up photographs agree with those of A. dolichopus. This rare species is illustrated with comments on its remarkable disjunct geographical distribution and ecology.