Biogeographic Events Research Articles

Defining the native and naturalised flora for the Australian continent

The value of distinguishing between plant species regarded as ‘native’ and ‘alien’ has special relevance in the island continent of Australia, where European settlement was a springboard for human-assisted plant dispersal. The year of European settlement is proposed here as providing a distinction between a ‘native’ and ‘naturalised’ flora and is applied for the entire Australian flora of vascular plants. Herbarium collections and ecological criteria were employed to determine the status of 168 species of ambiguous origin. The date of 1788 proved to be a relatively straightforward criterion to assign native and naturalised status and the origin of only 27 plant species remains ambiguous. The dispersal of plants between continents is an ongoing process but European settlement of the Australian continent represents a very sharp biogeographic event for the Australian flora and provides a straightforward criterion for determining the ‘naturalised’ species.

A new southern Laramidian ankylosaurid, Akainacephalus johnsoni gen. et sp. nov., from the upper Campanian Kaiparowits Formation of southern Utah, USA.

A partial ankylosaurid skeleton from the upper Campanian Kaiparowits Formation of southern Utah is recognized as a new taxon, Akainacephalus johnsoni, gen. et sp. nov. The new taxon documents the first record of an associated ankylosaurid skull and postcranial skeleton from the Kaiparowits Formation. Preserved material includes a complete skull, much of the vertebral column, including a complete tail club, a nearly complete synsacrum, several fore- and hind limb elements, and a suite of postcranial osteoderms, making Akainacephalus johnsoni the most complete ankylosaurid from the Late Cretaceous of southern Laramidia. Arrangement and morphology of cranial ornamentation in Akainacephalus johnsoni is strikingly similar to Nodocephalosaurus kirtlandensis and some Asian ankylosaurids (e.g., Saichania chulsanensis, Pinacosaurus grangeri, and Minotaurasaurus ramachandrani); the cranium is densely ornamented with symmetrically arranged and distinctly raised ossified caputegulae which are predominantly distributed across the dorsal and dorsolateral regions of the nasals, frontals, and orbitals. Cranial caputegulae display smooth surface textures with minor pitting and possess a distinct conical to pyramidal morphology which terminates in a sharp apex. Character analysis suggests a close phylogenetic relationship with N. kirtlandensis, M. ramachandrani, Tarchia teresae, and S. chulsanensis, rather than with Late Cretaceous northern Laramidian ankylosaurids (e.g., Euoplocephalus tutus, Anodontosaurus lambei, and Ankylosaurus magniventris). These new data are consistent with evidence for distinct northern and southern biogeographic provinces in Laramidia during the late Campanian. The addition of this new ankylosaurid taxon from southern Utah enhances our understanding of ankylosaurid diversity and evolutionary relationships. Potential implications for the geographical distribution of Late Cretaceous ankylosaurid dinosaurs throughout the Western Interior suggest multiple time-transgressive biogeographic dispersal events from Asia into Laramidia.

Biogeographic regions and events of isolation and diversification of the endemic biota of the tropical Andes

Understanding the spatial and temporal evolution of biota in the tropical Andes is a major challenge, given the region's topographic complexity and high beta diversity. We used a network approach to find biogeographic regions (bioregions) based on high-resolution species distribution models for 151 endemic bird taxa. Then, we used dated molecular phylogenies of 14 genera to reconstruct the area history through a sequence of allopatric speciation processes. We identified 15 biogeographical regions and found 26 events of isolation and diversification within their boundaries that are independently confirmed with disjunct distributions of sister taxa. Furthermore, these events are spatially congruent with six geographical barriers related to warm and/or dry river valleys, discontinuities in elevation, and high peaks separating fauna from different range slopes. The most important barrier is the Marañon River Valley, which limits the boundaries of four bioregions and is congruent with eight phylogenetic distribution breaks, separating the Central and Northern Andes, where the most bioregions are found. We also show that many bioregions have diffuse and overlapping structures, with contact and transition zones that challenge previous conceptions of biogeographical regions as spatially simple in structure. This study found evidence that the drivers of our identified bioregions were processes of Andean uplift and mountain dispersal facilitated by temperature oscillations of the Pleistocene. Therefore, Andean bioregions were not formed from one simple biogeographical event in a certain time frame, but from a combination of vicariance and dispersal events, which occurred in different time periods.

Long distance dispersal in the assembly of floras: A review of progress and prospects in North America

AbstractHere, we review progress and prospects to explicitly test for long distance dispersal biogeographic events. Long distance dispersal represents a “jump” across some kind of barrier, such as a topographic feature or a zone of unsuitable climate and may include repeated jumps, or stepping‐stone dispersals. Long distance dispersals were considered integral for explaining the organization of biodiversity at large and small scales by early biogeographers, such as Darwin and Wallace. Darwin, Wallace, and others envisioned that long distance dispersals were predictable events because the vectors for dispersal, such as animals, winds, and currents, behaved in non‐random ways. However, these early biogeographers found that dispersal was hard to observe, and, later, with the advent of the theory of Continental Drift, vicariance became regarded as a better scientific explanation for the arrangement of biodiversity, because it represented a falsifiable hypothesis. Thus, long distance dispersal was reduced to a nuisance parameter in biogeography; a random possibility that could never fully be ruled out in a scenario in which evidence supported vicariance. Today, there is strong interest to more fully integrate long distance dispersal into understanding the assembly and organization of biodiversity on earth. In this review, we discuss progress and prospects for explicitly testing long distance dispersal hypotheses including through uses of molecular, morphological, paleontological, and informatics methods. We focus on hypothesis testing of long distance dispersals involved in the assembly of the flora of North America, which is a robust preliminary study system on account of its extant and extinct biodiversity being well‐catalogued.

Reconstructing the origins and the biogeography of species’ genomes in the highly reticulate allopolyploid-rich model grass genus Brachypodium using minimum evolution, coalescence and maximum likelihood approaches

The identification of homeologous genomes and the biogeographical analyses of highly reticulate allopolyploid-rich groups face the challenge of incorrectly inferring the genomic origins and the biogeographical patterns of the polyploids from unreliable strictly bifurcating trees. Here we reconstruct a plausible evolutionary scenario of the diverging and merging genomes inherited by the diploid and allopolyploid species and cytotypes of the model grass genus Brachypodium. We have identified the ancestral Brachypodium genomes and inferred the paleogeographical ranges for potential hybridization events that originated its allopolyploid taxa. We also constructed a comprehensive phylogeny of Brachypodium from five nuclear and plastid genes using Species Tree Minimum Evolution allele grafting and Species Network analysis. The divergence ages of the lineages were estimated from a consensus maximum clade credibility tree using fossil calibrations, whereas ages of origin of the diploid and allopolyploid species were inferred from coalescence Bayesian methods. The biogeographical events of the genomes were reconstructed using a stratified Dispersal-Extinction-Colonization model with three temporal windows. Our combined Minimum Evolution-coalescence-Bayesian approach allowed us to infer the origins and the identities of the homeologous genomes of the Brachypodium allopolyploids, matching the expected ploidy levels of the hybrids. To date, the current extant progenitor genomes (species) are only known for B. hybridum. Putative ancestral homeologous genome have been inherited by B. mexicanum, ancestral and recent genomes by B. boissieri, and only recently evolved genomes by B. retusum and the core perennial clade allopolyploids (B. phoenicoides, B. pinnatum 4x, B. rupestre 4x). We dissected the complex spatio-temporal evolution of ancestral and recent genomes and have detected successive splitting, dispersal and merging events for dysploid homeologous genomes in diverse geographical scenarios that have led to the current extant taxa. Our data support Mid-Miocene splits of the Holarctic ancestral genomes that preceded the Late Miocene origins of Brachypodium ancestors of the modern diploid species. Successive divergences of the annual B. stacei and B. distachyon diploid genomes were implied to have occurred in the Mediterranean region during the Late Miocene-Pliocene. By contrast, a profusion of splits, range expansions and different genome mergings were inferred for the perennial diploid genomes in the Mediterranean and Eurasian regions, with sporadic colonizations and further mergings in other continents during the Quaternary. A reliable biogeographical scenario was obtained for the Brachypodium genomes and allopolyploids where homeologous genomes split from their respective diploid counterpart lineages in the same ancestral areas, showing similar or distinct dispersals. By contrast, the allopolyploid taxa remained in the same ancestral ranges after hybridization and genome doubling events. Our approach should have utility in deciphering the genomic composition and the historical biogeography of other allopolyploid-rich organismal groups, which are predominant in eukaryotes.

Reconstructing the phylogenetic history of the tribe Leucocoryneae (Allioideae): Reticulate evolution and diversification in South America

At present, the Allioideae is included within the Amaryllidaceae, which is an economically important bulb crop subfamily that includes onion, garlic, and ornamental species worldwide. The Allioideae includes four tribes geographically disjunct namely: Allieae, widespread in the northern hemisphere, tribe Tulbaghieae distributed in South Africa, and tribes Leucocoryneae and Gilliesieae are endemic to South America. Although we agree with the current tribal circumscription of the Leucocoryneae including Beauverdia, Ipheion, Latace, Leucocoryne, Nothoscordum, and Tristagma, there are still taxonomic and phylogenetic uncertainties regarding the monophyly, phylogenetic relationships, and divergence time of several lineages in a biogeographic context. In this study, a comprehensive molecular phylogeny of the tribe Leucocoryneae was inferred based on nuclear ribosomal ITS and plastid (ndhF and matK) sequences. We used Bayesian inference and maximum parsimony analyses to predict ancestor-descendant relationships. Our results confirmed the monophyly of the four tribes of subfamily Allioideae. Similarly, within the Leucocoryneae, Ipheion, Leucocoryne, and Nothosocordum Sect. Inodorum were also monophyletic; Tristagma and Nothoscordum would be monophyletic if including Ipheion and Beauverdia, respectively. Network analyses were implemented to reveal putative scenarios of reticulate evolution. Both, current and ancestral hybridization events have presumably occurred among species of Nothoscordum Sect. Nothoscordum and Beauverdia favored by spatial overlapping of populations, flowering synchrony and a puzzling pattern of cytogenetic attributes. The estimation of divergence time indicates that the tribe Leucocoryneae originated in the Late Oligocene in southern South America with possible ancestors in Africa. Most crown lineages within the tribe diversified in conjunction with biogeographical events during the Late Miocene to Pliocene. We posit that new suitable environments available after the Andean uplift and during the Age of the Southern Plains provided the favorable geographic setting for the major lineages of Leucocoryneae in southern Pampas, extra-Andean Patagonia, Andean mountains, and in Chile. Hybridization, polyploidization, and Robertsonian translocations of chromosomes have been the driving forces and major sources of speciation in the evolution of tribe Leucocoryneae.

A Post-pleistocene Calibrated Mutation Rate from Insect Museum Specimens.

Quantifying the age of recent species divergence events can be challenging in the absence of calibration points within many groups. The katydid species Neoconocephalus lyristes provides the opportunity to calibrate a post-Pleistocene, taxa specific mutation rate using a known biogeographic event, the Mohawk-Hudson Divide. DNA was extracted from pinned museum specimens of N. lyristes from both Midwest and Atlantic populations and the mitochondrial gene COI sequenced using primers designed from extant specimens. Coalescent analyses using both strict and relaxed molecular clock models were performed in BEAST v1.8.2. The assumption of a strict molecular clock could not be rejected in favor of the relaxed clock model as the distribution of the standard deviation of the clock rate strongly abutted zero. The strict molecular clock model resulted in an intraspecific calculated mutation rate of 14.4-17.3 %/myr, a rate substantially higher than the common rates of sequence evolution observed for insect mitochondrial DNA sequences. The rate, however, aligns closely with mutation rates estimated from other taxa with similarly recent lineage divergence times.

The phylogeography of the cycad genus Dioon (Zamiaceae) clarifies its Cenozoic expansion and diversification in the Mexican transition zone.

Biogeographic transition zones are promising areas to study processes of biogeographic evolution and its influence on biological groups. The Mexican transition zone originated due to the overlap of Nearctic and Neotropical biota, which promoted great biological diversification. However, since most previous studies in this area were focused on revealing the phylogeography of Nearctic plants, how historical biogeographic configuration influenced the expansion and diversification of the Neotropical flora remains almost unknown. Using the cycad genus Dioon (Zamiaceae), this study aimed to test whether the biogeographic provinciality of the Mexican transition zone reflects the history of diversification of Neotropical plants. Two chloroplast DNA (cpDNA) regions were analysed from 101 specimens of 15 Dioon species to reveal the distribution of haplogroups. In addition, genome-wide single nucleotide polymorphisms (SNPs) from 84 specimens were used to test the concordance between phylogenetic clusters and the biogeographic provinces. An ultrametric tree was constructed from the sequences containing SNPs to reconstruct the biogeographic events of vicariance and dispersal of Dioon across the Neotropical biogeographic provinces. Four Dioon lineages with strong phylogeographic structures were recognized using both cpDNA and SNP data. The lineages correspond to two clades that originated from a common ancestor in Eastern Mexico. One clade expanded and diversified in South-east Mexico and Central America. Another clade diversified into three lineages that dispersed to North-east, South and North-west Mexico. Each lineage was biogeographically delimitated. Biogeographic provinces might have provided disparate ecological conditions that facilitated speciation in Dioon since the Miocene. The current genetic structure and species diversity of Dioon depict the history of expansion and diversification of the northernmost Neotropical provinces. Past biogeographic connectivities were favoured by elevated topographies, since mountain systems served as corridors for the migration of Dioon and as refugia of tropical communities that diversified during the formation of modern Neotropical forests.

An early Oligocene occurrence of the palaeoendemic genus Dipteronia (Sapindaceae) from Southwest China

Palaeoendemic plants, whose past geographical distribution was much larger than their present distribution ranges, play an important role in reconstructing biogeographical events, and in tracking floristic relationships among continents throughout geological time. Improving knowledge about their geographical histories helps to understand the evolution of biodiversity under palaeoenvironmental changes. Here, we report the first fossil record of Dipteronia from East Asia, namely Dipteronia brownii McClain et Manchester, based on diagnostic winged fruit remains from the Rupelian (c. 32±1Ma) of the Lühe Basin in southwestern China. The fossil species is characterized by (i) a samaroid mericarp, with an orbicular wing, (ii) a primary vein extending from the attachment scar, and ramifying into secondary and tertiary veins that radiate out from the seed body area and dichotomize toward the mericarp. Dipteronia was widely distributed in the Northern Hemisphere during the Palaeogene and is now endemic to central and southwestern China with two extant species. This new finding significantly expands the historical distribution of Dipteronia into China by the early Oligocene, and its present-day endemism is apparently the result of extirpation from North America and the higher latitudes of Asia associated with Cenozoic climatic changes.

Still slow, but even steadier: an update on the evolution of turtle cranial disparity interpolating shapes along branches.

In a previous study, we estimated the cranial disparity of turtles (Testudinata) through time using geometric morphometric data from both terminal taxa and hypothetical ancestors to compensate for temporal gaps in the fossil record. While this method yielded reasonable results for the Mesozoic and the early Cenozoic, we found a large drop in cranial disparity for the Miocene, for which we found no correlation with known environmental changes or extinction events. Instead, we speculated that the Miocene dip was a result of poor sampling of fossils or ancestors in this time bin. To countervail this problem, we here updated our original dataset and interpolated changes of shape along the branch lengths and compared them with the previous data. We furthermore explored the impact of topological and temporal uncertainty, demonstrating that the Miocene dip, indeed, is a sampling artefact. All remaining conclusions of the previous study could be more or less supported, nevertheless, including an apparent correlation with global biogeographic events, a minor correlation between cranial disparity and global temperature, and resilience across the K/T extinction event.

Genetic variation of complete mitochondrial genome sequences of the Sumatran rhinoceros (Dicerorhinus sumatrensis)

The Sumatran rhinoceros (Dicerorhinus sumatrensis) is the smallest and one of the most endangered rhinoceros species, with less than 100 individuals estimated to live in the wild. It was originally divided into three subspecies but only two have survived, D. sumatrensis sumatrensis (Sumatran subspecies), and D. s. harrissoni (Bornean). Questions regarding whether populations of the Sumatran rhinoceros should be treated as different management units to preserve genetic diversity have been raised, particularly in light of its severe decline in the wild and low breeding success in captivity. This work aims to characterize genetic differentiation between Sumatran rhinoceros subspecies using complete mitochondrial genomes, in order to unravel their maternal evolutionary history and evaluate their status as separate management units. We identified three major phylogenetic groups with moderate genetic differentiation: two distinct haplogroups comprising individuals from both the Malay Peninsula and Sumatra, and a third group from Borneo. Estimates of divergence time indicate that the most recent common ancestor of the Sumatran rhinoceros occurred approximately 360,000 years ago. The three mitochondrial haplogroups showed a common divergence time about 80,000 years ago corresponding with a major biogeographic event in the Sundaland region. Patterns of mitochondrial genetic differentiation may suggest considering Sumatran rhinoceros subspecies as different conservation units. However, the management of subspecies as part of a metapopulation may appear as the last resource to save this species from extinction, imposing a conservation dilemma.

A short-range endemic species from south-eastern Atlantic Rain Forest shows deep signature of historical events: phylogeography of harvestmen Acutisoma longipes (Arachnida: Opiliones)

The Brazilian Atlantic Rain Forest is amongst the most diverse biomes in the world, but the processes that shaped its biodiversity are still poorly understood. We used one mitochondrial and two nuclear markers to evaluate the phylogeographic patterns of the endemic harvestman Acutisoma longipes and its closely related species to investigate the biogeographic history of this biome. The results showed low intrapopulation diversity and strong population structure, suggesting poor dispersion amongst locations. Phylogenetic analyses pointed to three main mitochondrial lineages congruent with the geomorphology of the south-eastern region of Brazil (Serra do Mar, Serra da Mantiqueira, and interior plateau). These older divergences occurred in the middle-Neogene, suggesting that events in this period drove the diversification of the species, but Quaternary events also affected the populations locally. We detected some congruence between A. longipes demographic patterns and the areas of endemism delimited for harvestmen, suggesting that some regions of the distribution could have been more stable in the past (especially in Serra da Mantiqueira). Our findings corroborate that harvestmen are a suitable group for the study of ancient biogeographic events in the Atlantic Rain Forest, even at small-scale ranges. Acutisoma hamatum is here considered as a new junior synonym of A. longipes.

The hidden anatomy of paranasal sinuses reveals biogeographically distinct morphotypes in the nine-banded armadillo (Dasypus novemcinctus).

BackgroundWith their Pan-American distribution, long-nosed armadillos (genus Dasypus) constitute an understudied model for Neotropical biogeography. This genus currently comprises seven recognized species, the nine-banded armadillo (D. novemcinctus) having the widest distribution ranging from Northern Argentina to the South-Eastern US. With their broad diversity of habitats, nine-banded armadillos provide a useful model to explore the effects of climatic and biogeographic events on morphological diversity at a continental scale.MethodsBased on a sample of 136 skulls of Dasypus spp. belonging to six species, including 112 specimens identified as D. novemcinctus, we studied the diversity and pattern of variation of paranasal cavities, which were reconstructed virtually using µCT-scanning or observed through bone transparency.ResultsOur qualitative analyses of paranasal sinuses and recesses successfully retrieved a taxonomic differentiation between the traditional species D. kappleri, D. pilosus and D. novemcinctus but failed to recover diagnostic features between the disputed and morphologically similar D. septemcinctus and D. hybridus. Most interestingly, the high variation detected in our large sample of D. novemcinctus showed a clear geographical patterning, with the recognition of three well-separated morphotypes: one ranging from North and Central America and parts of northern South America west of the Andes, one distributed across the Amazonian Basin and central South America, and one restricted to the Guiana Shield.DiscussionThe question as to whether these paranasal morphotypes may represent previously unrecognized species is to be evaluated through a thorough revision of the Dasypus species complex integrating molecular and morphological data. Remarkably, our recognition of a distinct morphotype in the Guiana Shield area is congruent with the recent discovery of a divergent mitogenomic lineage in French Guiana. The inflation of the second medialmost pair of caudal frontal sinuses constitutes an unexpected morphological diagnostic feature for this potentially distinct species. Our results demonstrate the benefits of studying overlooked internal morphological structures in supposedly cryptic species revealed by molecular data. It also illustrates the under-exploited potential of the highly variable paranasal sinuses of armadillos for systematic studies.

Alto de Ballester, biogeographical consequences of atypical MN 3 micromammal assemblages from eastern Spain

The small mammal assemblages from Alto de Ballester 1 and 2 in the Rubielos de Mora basin represent a unique faunal assemblage from the late early Miocene (Ramblian, MN 3). Together, the assemblages yielded five species of rodents (Peridyromys murinus, P. aff. murinus, P. aquatilis, Pseudotheridomys aff. fejfari and cf. Steneofiber depereti), and nine insectivores (Galericinae indet., Desmanella fejfari, Myxomygale minor, Desmanodon daamsi, Chainodus cf. sulcatus, Heterosorex sp., cf. Oligosorex thauensis, cf. Clapasorex alvarezae, and Paenelimnoecus cf. truyolsi). High abundance and diversity of insectivores, and the presence of a beaver and a dimylid show that the assemblages represent a humid, forested environment. This is in line with the palaeobotanical evidence of the basin. The two Alto de Ballester assemblages, which are very different from other Ramblian faunas, show that there was a variety of ecosystems on the Iberian Peninsula at this period, probably drier in the inland and more humid near the coastal zone.

Estimation of Evolutionary Rates of Mitochondrial DNA in Two Japanese Wood Mouse Species Based on Calibrations with Quaternary Environmental Changes.

Reliable estimates of evolutionary rates of mitochondrial DNA might allow us to build realistic evolutionary scenarios covering broad time scales based on phylogenetic inferences. In the present study, we sought to obtain estimates of evolutionary rates in murine rodents using calibrations against historical biogeographic events. We first assumed that land-bridge-like structures that appeared intermittently at glacial maxima with 100,000-year intervals shaped the divergence patterns of cytochrome b (Cytb) sequences (1140 bp) of the larger Japanese wood mouse Apodemus speciosus. The comparison of sequences from peripheral remote islands that are separated from one another by deep straits allowed us to estimate mitochondrial DNA evolutionary rates (substitutions/site/million years) to be 0.027 to 0.036, with presumed calibrations from 140,000, 250,000, 350,000, and 440,000 years ago. Second, we addressed rapid expansion events inferred from analyses of the Cytb sequences of the lesser Japanese wood mouse A. argenteus. We detected five expansion signals in the dataset and established three categories based on the expansion parameter tau values: 3.9, 5.6-5.7, and 7.8-8.1. Considering that the climate became warmer 15,000, 53,000, and 115,000 years ago after preceding periods of rapid cooling, we calculated evolutionary rates to be 0.114, 0.047, and 0.031, respectively. This preliminary concept of the evolutionary rates on a time scale from 15,000 to 440,000 years ago for the wood mouse should be refined and tested in other species of murine rodents, including mice and rats.

An event model for phylogenetic biogeography using explicitly geographical ranges

AbstractAimTo develop and implement a method for phylogenetic biogeography that is both event based and geographically explicit, that is, that uses the geographical ranges observed in the terminals instead of ‘predefined areas.’MethodsThe method, GEM (Geographically explicit Event Model), attributes vicariance, sympatry (range copying), point sympatry (subset sympatry) or founder events, to the internal nodes of the tree. The cost of a reconstruction is calculated as the event cost plus the amount of range changes along a branch, and the best reconstruction is the combination of the event and range assignments that minimize the cost.ResultsThe approach was implemented in a computer program, evs, using a geographical data model (a raster) in which range changes were measured by pixel counts. The program can be used in real‐sized datasets, using an heuristic to find reasonable solutions in short times.Main conclusionGEM provides a method for direct analysis of joint data on phylogeny and explicit distribution ranges, and proposes both the ancestral ranges and the biogeographical events connected with cladogenesis.

Contrasting dispersal histories of broad‐ and fine‐leaved temperate Loliinae grasses: range expansion, founder events, and the roles of distance and barriers

AbstractAimSuccessful colonization after long‐distance dispersal (LDD) depends on the availability of suitable habitats and competitive ability. In this study, we address the hypothesis that two widely distributed sister grass lineages (broad‐ and fine‐leaved Loliinae; hereafter BL and FL) that differ in their habitat requirements and competitive ability also differ in their biogeographic history, with particular reference to LDD.LocationGlobal.MethodsWe reconstructed a comprehensive phylogeny of Loliinae, based on nuclear and plastid markers and estimated divergence times using fossil calibrations. Biogeographical events were estimated using analysis of range evolution, comparing different models. Numbers and rates of dispersals were estimated for BL and FL using stochastic mapping with best‐performing and baseline biogeographical models, and examined for correlation with distance, disjunction type, and phenotypic syndrome.ResultsThe most recent common ancestor of Loliinae likely split at the Oligocene‐Miocene transition (22.50 ± 3.95 Ma), pre‐dating previous estimates, whereas the ancestors of the BL and FL Loliinae likely began to diversify in the Early Miocene (18.91 ± 4.15 and 17.50 ± 3.50 Ma, respectively). A model of range evolution integrating founder events and scaling of dispersal by shortest distance between areas performed best amongst a set of alternative models and recovered a mean of 83 dispersal events in Loliinae. Overall dispersal rates were significantly higher in BL than in FL. Per‐route dispersal rates showed a significant negative exponential relationship to shortest distance but were not affected by phenotypic syndrome or disjunction type.Main conclusionsLoliinae originated in the Northern Hemisphere and evolved through recurrent LDDs. Higher competitive ability, potentially related to the broad‐leaved syndrome (i.e. tall strong‐rhizomatous plants, long‐living individuals, occupancy of more stable habitats), may explain higher observed dispersal rates in BL compared with FL Loliinae. However, the dominant factor impacting dispersal in both BL and FL Loliinae is the distance between suitable areas.

Did interaction between human pressure and Little Ice Age drive biological turnover in New Zealand?

AbstractAimTo test for simultaneous Holocene biogeographic turnover events in the New Zealand region. Specifically, we synthesize ancient DNA, radiocarbon data and archaeological data to assess the chronologies of late Holocene lineage extinction and replacement.LocationCool‐temperate coastal ecosystems of New Zealand and the subantarctic.MethodsWe present new ancient DNA and radiocarbon data for New Zealand sea lions, and synthesize existing climatic, genetic and archaeological data, to test for synchronous megafaunal extinction and replacement events. The collated data include ancient DNA sequences from over 200 ancient sea lion and penguin specimens, in addition to 150 modern genetic samples.ResultsOur temporal genetic analyses show that, following human‐driven extinction events, synchronous marine megafaunal replacement events occurred at around 1500 AD, coinciding with the Little Ice Age onset and an associated drastic human demographic decline in southern New Zealand.ConclusionsA combination of climatic and human demographic shifts likely facilitated northward expansion of subantarctic sea lion and penguin lineages, replacing extirpated mainland New Zealand marine megafauna. Broadly, the interaction between human pressure and late Holocene climatic change may explain multiple biological turnover events in the Southern Hemisphere.

Biogeographic Events Are Not Correlated with Diaspore Dispersal Modes in Boraginaceae

Long-distance dispersal seems to be the main biogeographic event responsible for intriguing distribution patterns in plant groups in which sister taxa are separated by thousands of kilometers of distance across oceans and continents. The biotic and abiotic mechanisms behind such dispersal events are poorly understood and many attempts have been made to explain how plants can manage to disperse and survive these long journeys. The biogeographic history of Boraginaceae, a subcosmopolitan plant family with many disjunct clades, is here addressed and analyzed in the context of the different dispersal modes exhibited by the species. The lack of a clear pattern between the main dispersal events in Boraginaceae and the phylogenetic distribution of the dispersal modes indicates that no single dispersal mechanism can be associated with the events of dispersal in the family. Moreover, adaptations to different dispersal agents and unassisted dispersal modes in some clades might have promoted the diversification of Boraginaceae in various habitats across several continents. Our study reveals that long-distance dispersal is a very complex process that needs to be analyzed in the context of climatic and environmental changes and the response of plants and their dispersal vectors to these variable conditions.

Phylogeny and biogeography of South Chinese brown frogs (Ranidae, Anura).

Few studies have explored the role of Cenozoic tectonic evolution in shaping the patterns and processes of extant animal distributions in and around East Asia. In this study, we selected South Chinese brown frogs as a model to examine the phylogenetic and biogeographical consequences of Miocene tectonic events within South China and its margins. We used mitochondrial and nuclear molecular data to reconstruct phylogenetic interrelationships among Chinese brown frogs using Bayesian and maximum likelihood analyses. The phylogeny results show that there are four main clades of Chinese brown frogs. Excepting the three commonly known Chinese brown frog species groups, R. maoershanensis forms an independent clade nearest to the R. japonica group. Phylogeny and P-distance analyses confirmed R. maoershanensis as a valid species. Among South Chinese brown frogs, there are four subclades associated with four geographical areas: (I) R. maoershanensis; (II) R. japonica; (III) R. chaochiaoensis; and (IV) other species of the R. longicrus species group. Divergence times, estimated using mitochondrial sequences, place the vicariance events among the four subclades in the middle to late Miocene epoch. Our results suggest that (1) South Chinese brown frogs originated due to a vicariance event separating them from the R. chensinensis species group at the time of the Geological movement (~18 million years ago, Ma) in southern Tibet and the Himalayan region; (2) the separation and speciation of R. maoershanensis from the R. japonica group occurred due to the dry climate at approximately 16 Ma; (3) South Chinese brown frogs migrated from South China to Japan at the time (~10.8 Ma) that the global sea-level fell and the East China Sea Shelf Basin was swamp facies, when a land gallery may have formed across the sea to connect the two areas; and (4) R. chaochiaoensis separated from other species of the R. longicrus species group during the uplift of the Tibetan Plateau at approximately 9.5 Ma.