Transoceanic Dispersal Research Articles

A brief review of non-avian dinosaur biogeography: state-of-the-art and prospectus.

Dinosaurs potentially originated in the mid-palaeolatitudes of Gondwana 245-235 million years ago (Ma) and may have been restricted to cooler, humid areas by low-latitude arid zones until climatic amelioration made northern dispersals feasible ca 215 Ma. However, this scenario is challenged by new Carnian Laurasian fossils and evidence that even the earliest dinosaurs had adaptations for arid conditions. After becoming globally distributed in the Early-Middle Jurassic (200-160 Ma), dinosaurs experienced vicariance driven by Pangaean fragmentation. Regional extinctions and trans-oceanic dispersals also played a role, and the formation of ephemeral land connections meant that older vicariance patterns were repeatedly overprinted by younger ones, creating a reticulate biogeographic history. Palaeoclimates shaped dispersal barriers and corridors, including filters that had differential effects on different types of dinosaurs. Dinosaurian biogeographic research faces many challenges, not the least of which is the patchiness of the fossil record. However, new fossils, extensive databasing and improved analytical methods help distinguish signal from noise and generate fresh perspectives. In the future, developing techniques for quantifying and ameliorating sampling biases and modelling the dispersal capacities of dinosaurs are likely to be two of the key components in our modern research programme.

Evidence for a floristically diverse rainforest on the Falkland archipelago in the remote South Atlantic during the mid- to late Cenozoic

Abstract We report the discovery of an ancient forest bed near Stanley, on the Falkland Islands, the second such ancient deposit identified on the South Atlantic island archipelago that is today marked by the absence of native tree species. Fossil pollen, spores and wood fragments preserved in this buried deposit at Tussac House show that the source vegetation was characterized by a floristically diverse rainforest dominated by Nothofagus-Podocarpaceae communities, similar to cool temperate Nothofagus forests/woodlands and Magellanic evergreen Nothofagus rainforests. The age limit of the deposit is inferred from the stratigraphic distribution of fossil pollen species transported by wind, birds or ocean currents from southern Patagonia, as well as similar vegetation types observed across the broader region. The deposit is suggested to be between Late Oligocene and Early Miocene, making it slightly older than the previously analysed Neogene West Point Island forest bed (200 km west of Tussac House). The combined evidence adds to our current knowledge of the role of climate change and transoceanic dispersal of plant propagules in shaping high-latitude ecosystems in the Southern Hemisphere during the late Palaeogene and Neogene.

Endocranial anatomy and phylogenetic position of the crocodylian Eosuchus lerichei from the late Paleocene of northwestern Europe and potential adaptations for transoceanic dispersal in gavialoids.

Eosuchus lerichei is a gavialoid crocodylian from late Paleocene marine deposits of northwestern Europe, known from a skull and lower jaws, as well as postcrania. Its sister taxon relationship with the approximately contemporaneous species Eosuchus minor from the east coast of the USA has been explained through transoceanic dispersal, indicating a capability for salt excretion that is absent in extant gavialoids. However, there is currently no anatomical evidence to support marine adaptation in extinct gavialoids. Furthermore, the placement of Eosuchus within Gavialoidea is labile, with some analyses supporting affinities with the Late Cretaceous to early Paleogene "thoracosaurs." Here we present novel data on the internal and external anatomy of the skull of E. lerichei that enables a revised diagnosis, with 6 autapormorphies identified for the genus and 10 features that enable differentiation of the species from Eosuchus minor. Our phylogenetic analyses recover Eosuchus as an early diverging gavialid gavialoid that is not part of the "thoracosaur" group. In addition to thickened semi-circular canal walls of the endosseous labyrinth and paratympanic sinus reduction, we identify potential osteological correlates for salt glands in the internal surface of the prefrontal and lacrimal bones of E. lerichei. These salt glands potentially provide anatomical evidence for the capability of transoceanic dispersal within Eosuchus, and we also identify them in the Late Cretaceous "thoracosaur" Portugalosuchus. Given that the earliest diverging and stratigraphically oldest gavialoids either have evidence for a nasal salt gland and/or have been recovered from marine deposits, this suggests the capacity for salt excretion might be ancestral for Gavialoidea. Mapping osteological and geological evidence for marine adaptation onto a phylogeny indicates that there was probably more than one independent loss/reduction in the capacity for salt excretion in gavialoids.

A trans-oceanic flight of over 4,200 km by painted lady butterflies

The extent of aerial flows of insects circulating around the planet and their impact on ecosystems and biogeography remain enigmatic because of methodological challenges. Here we report a transatlantic crossing by Vanessa cardui butterflies spanning at least 4200 km, from West Africa to South America (French Guiana) and lasting between 5 and 8 days. Even more, we infer a likely natal origin for these individuals in Western Europe, and the journey Europe-Africa-South America could expand to 7000 km or more. This discovery was possible through an integrative approach, including coastal field surveys, wind trajectory modelling, genomics, pollen metabarcoding, ecological niche modelling, and multi-isotope geolocation of natal origins. The overall journey, which was energetically feasible only if assisted by winds, is among the longest documented for individual insects, and potentially the first verified transatlantic crossing. Our findings suggest that we may be underestimating transoceanic dispersal in insects and highlight the importance of aerial highways connecting continents by trade winds.

Fossil-informed biogeographic analysis suggests Eurasian regionalization in crown Squamata during the early Jurassic.

Squamata (lizards, snakes, and amphisbaenians) is a Triassic lineage with an extensive and complex biogeographic history, yet no large-scale study has reconstructed the ancestral range of early squamate lineages. The fossil record indicates a broadly Pangaean distribution by the end- Cretaceous, though many lineages (e.g., Paramacellodidae, Mosasauria, Polyglyphanodontia) subsequently went extinct. Thus, the origin and occupancy of extant radiations is unclear and may have been localized within Pangaea to specific plates, with potential regionalization to distinct Laurasian and Gondwanan landmasses during the Mesozoic in some groups. We used recent tectonic models to code extant and fossil squamate distributions occurring on nine discrete plates for 9,755 species, with Jurassic and Cretaceous fossil constraints from three extinct lineages. We modeled ancestral ranges for crown Squamata from an extant-only molecular phylogeny using a suite of biogeographic models accommodating different evolutionary processes and fossil-based node constraints from known Jurassic and Cretaceous localities. We hypothesized that the best-fit models would not support a full Pangaean distribution (i.e., including all areas) for the origin of crown Squamata, but would instead show regionalization to specific areas within the fragmenting supercontinent, likely in the Northern Hemisphere where most early squamate fossils have been found. Incorporating fossil data reconstructs a localized origin within Pangaea, with early regionalization of extant lineages to Eurasia and Laurasia, while Gondwanan regionalization did not occur until the middle Cretaceous for Alethinophidia, Scolecophidia, and some crown Gekkotan lineages. While the Mesozoic history of extant squamate biogeography can be summarized as a Eurasian origin with dispersal out of Laurasia into Gondwana, their Cenozoic history is complex with multiple events (including secondary and tertiary recolonizations) in several directions. As noted by previous authors, squamates have likely utilized over-land range expansion, land-bridge colonization, and trans-oceanic dispersal. Tropical Gondwana and Eurasia hold more ancient lineages than the Holarctic (Rhineuridae being a major exception), and some asymmetries in colonization (e.g., to North America from Eurasia during the Cenozoic through Beringia) deserve additional study. Future studies that incorporate fossil branches, rather than as node constraints, into the reconstruction can be used to explore this history further.

Phylogenetic placement of Carex dianae Steud., a sedge endemic to the South Atlantic island of St. Helena

Carex dianae Steud. is an endemic sedge of St. Helena, an isolated island in the South Atlantic. Our study provides the first molecular sequence data for this taxon. We generated sequence data for plastid matK and trnK regions and nuclear internal transcribed spacer and external transcribed spacer regions to determine the placement of C. dianae in the broader Carex phylogeny. The placement of C. dianae falls within Carex sect. Spirostachyae Drejer, and it is sister to a clade including Carex clavata Thunb., Carex aethiopica Schkuhr (both from the Cape region of S. Africa), and Carex gunniana Boott (southern Australia). The existence of three divergent nucleotype groups and two plastotypes is revealed from genetic variation within C. dianae. The results suggest that the ancestor of C. dianae likely originated in the Cape region of South Africa, followed by transoceanic dispersal to St. Helena estimated at 4.4–4.9 million years ago, likely by a bird vector. The most divergent population is that on an isolated hill known as “The Barn”, which may represent a distinct taxon. The existence of highly structured molecular variation within an island only 16 km long is discussed.

Phylogeny of Berberidopsidales based on nuclear and chloroplast loci, with the description of a new species of Berberidopsis endemic to Central Chile

AbstractBerberidopsidales comprises two families: monotypic Aextoxicaceae (Aextoxicon punctatum in Chile and Argentina) and Berberidopsidaceae. The latter includes Australian monotypic Streptothamnus (S. moorei) and Berberidopsis (B. beckleri in Australia and B. corallina in Chile). A new Berberidopsis species from the Central Chilean Andes is here described. Phylogenetic analyses based on nuclear and chloroplast data clarified the relationships within Berberidopsidales. The new species, Berberidopsis granitica, is sister to the Chilean endemic B. corallina, and this clade is sister to the Australian B. beckleri. The dated molecular phylogeny places the split between the South American B. corallina and B. granitica into the late Miocene/early Pleistocene and the split between South American and Australian Berberidopsis to the late Miocene and Pliocene, suggesting transoceanic dispersal rather than vicariance. Climatic niche analyses show two distinct and non‐overlapping climatic niches for the Australian and southern South American species. Berberidopsis granitica and B. corallina also differ clearly in their habitat and morphology, in addition to their climatic niche. Berberidopsis granitica has a very restricted distribution area and grows in the Andes under montane climatic conditions, unique within Berberidopsidales.

Fossil-calibrated phylogenies of Southern cave wētā show dispersal and extinction confound biogeographic signal.

The biota of continents and islands are commonly considered to have a source-sink relationship, but small islands can harbour distinctive taxa. The distribution of four monotypic genera of Orthoptera on young subantarctic islands indicates a role for long-distance dispersal and extinction. Phylogenetic relationships were inferred from whole mtDNA genomes and nuclear sequences (45S cassette; four histones). We used a fossil and one palaeogeographic event to calibrate molecular clock analysis. We confirm that neither the Australian nor Aotearoa-New Zealand Rhaphidophoridae faunas are monophyletic. The radiation of Macropathinae may have begun in the late Jurassic, but trans-oceanic dispersal is required to explain the current distribution of some lineages within this subfamily. Dating the most recent common ancestor of seven island endemic species with their nearest mainland relative suggests that each existed long before their island home was available. Time estimates from our fossil-calibrated molecular clock analysis suggest several lineages have not been detected on mainland New Zealand, Australia, or elsewhere most probably due to their extinction, providing evidence that patterns of extinction, which are not consistently linked to range size or lineage age, confound biogeographic signal.

Independent origins or single dispersal? Phylogenetic study supports early Cenozoic origin of three endemic Indo‐Sri Lankan Lygosomine skink genera

AbstractThe Western Ghats‐Sri Lanka biodiversity hotspot is home to three endemic Lygosomine (Reptilia, Scincidae) skink genera—Kaestlea, Ristella and Lankascincus. Phylogenetic reconstructions in the past have suggested a sister relationship between the Western Ghats endemic Ristella and the Sri Lankan endemic Lankascincus, while the placement of Kaestlea has been uncertain. We reconstruct a global, genus‐level, multi‐locus phylogeny of the sub‐family Lygosominae to ask if these endemic genera share an immediate common ancestor, that is, did they arise from a single dispersal event? Furthermore, to understand the possible centres of origin and dispersal routes of these three genera of Indo‐Sri Lankan skinks, we construct a time‐calibrated phylogeny and perform ancestral range evolution. We find that Kaestlea does not share an immediate ancestor with Ristella + Lankascincus. Therefore, their presence in the Indian subcontinent results from two independent colonization events. Both these dispersal events likely occurred during the late Palaeocene‐early Eocene from the Asian landmass. Our molecular dating and ancestral range evolution analyses add further evidence of probable transoceanic dispersal in skinks and early land connections between the Indian subcontinent and Asia. It also reveals that these skinks were some of the earliest lizards to disperse into the Indian subcontinent.

A new species of Kana Distant representing the first record of Evacanthinae (Hemiptera: Cicadellidae) from Madagascar.

Kana ranomafanensis sp. n. is described and illustrated based on specimens from montane rainforests in eastern Madagascar. This is the first record of the diverse and widely distributed leafhopper subfamily Evacanthinae from Madagascar. A revised diagnosis of Kana Distant is provided and the new species is compared to species from the Indomalayan and Afrotropical regions. Evidence from previous molecular divergence time analyses suggests that ancestors of the new species arrived in Madagascar via transoceanic dispersal. The ovipositor of the genus and the male genitalia of Kana decora (Melichar), previously known only from the female holotype from Sri Lanka, are illustrated for the first time.

A comprehensive genus-level phylogeny and biogeographical history of the Lythraceae based on whole plastome sequences.

The Lythraceae are a mainly subtropical to tropical family of the order Myrtales with 28 currently accepted genera and approximately 600 species. There is currently no well-supported phylogenetic and biogeographical hypothesis of the Lythraceae incorporating all currently accepted genera, which we sought to provide. Plastomes of representative species of 18 distinct Lythraceae genera were sequenced and annotated. Together with existing sequences, plastomes of all 28 currently accepted genera in the Lythraceae were brought together for the first time. The plastomes were aligned and a Bayesian phylogenetic hypothesis was produced. We then conducted a time-calibrated Bayesian analysis and a biogeographical analysis. Plastome-based Bayesian and maximum-likelihood phylogenetic trees are generally congruent with recent nuclear phylogenomic data and resolve two deeply branching major clades in the Lythraceae. One major clade concentrates shrubby and arboreal South American and African genera that inhabit seasonally dry environments, with larger, often winged seeds, adapted to dispersal by the wind. The second major clade concentrates North American, Asian, African and several near-cosmopolitan herbaceous, shrubby and arboreal genera, often inhabiting humid or aquatic environments, with smaller seeds possessing structures that facilitate dispersal by water. We hypothesize that the Lythraceae dispersed early in the Late Cretaceous from South American to North American continents, with subsequent expansion in the Late Cretaceous of a North American lineage through Laurasia to Africa via a boreotropical route. Two later expansions of South American clades to Africa in the Palaeocene and Eocene, respectively, are also hypothesized. Transoceanic dispersal in the family is possibly facilitated by adaptations to aquatic environments that are common to many extant genera of the Lythraceae, where long-distance dispersal and vicariance may be invoked to explain several remarkable disjunct distributions in Lythraceae clades.

Gossypium purpurascens genome provides insight into the origin and domestication of upland cotton

IntroductionAllotetraploid upland cotton (Gossypium hirsutum L.) is native to the Mesoamerican and Caribbean regions, had been improved in the southern United States by the mid-eighteenth century, was then dispersed worldwide. However, a Hainan Island Native Cotton (HIC) has long been grown extensively on Hainan Island, China. ObjectivesExplore HIC’s evolutionary relationship and genomic diversity with other tetraploid cottons, its origin and whether it was used for YAZHOUBU (Yazhou cloth, World Intangible Cultural Heritage) weaving, and the role of structural variations (SVs) in upland cotton domestication. MethodsWe assembled a high-quality genome of one HIC plant. We performed phylogenetic analysis, divergence time estimation, principal component analysis and population differentiation estimation using cotton assemblies and/or resequencing data. SVs were detected by whole-genome comparison. A F2 population was used for linkage analysis and to study effects of SVs. Buoyancy and salt water tolerance tests for seeds were conducted. ResultsWe found that the HIC belongs to G. purpurascens. G. purpurascens is best classified as a primitive race of G. hirsutum. The potential for long range transoceanic dispersal of G. purpurascens seeds was proved. A set of SVs, selective sweep regions between G. hirsutum races and cultivars, and quantitative trait loci (QTLs) of eleven agronomic traits were obtained. SVs, especially large-scale SVs, were found to have important effects on cotton domestication and improvement. Of them, eight large-scale inversions strongly associated with yield and fiber quality have probably undergone artificial selection in domestication. ConclusionG. purpurascens including HIC is a primitive race of G. hirsutum, probably disperse to Hainan from Central America by floating on ocean currents, may have been partly domesticated, planted and was likely used for YAZHOUBU weaving in Hainan much earlier than the Pre-Columbian period. SV plays an important role in cotton domestication and improvement.

Gondwanan origin of the Dipterocarpaceae-Cistaceae-Bixaceae is supported by fossils, areocladograms, ecomorphological traits and tectonic-plate dynamics

There is disparity between the estimated time of origin of the ‘superclade’ Dipterocarpaceae sensu lato, that includes Sarcolaenaceae, Cistaceae, Pakaraimaea, Bixaceae, Cochlospermaceae and Sphaerosepalaceae, as determined by recent molecular phylogenies (100−85 million years ago, Ma) and its strongly tropical, South American-African-Madagascan-SE Asian distribution that indicates an older Gondwanan origin (>110 Ma). We used several paleobiogeographic approaches, including recently reported fossil records, to explore the hypothesis that Dipterocarpaceae sl has a Gondwanan/early-Cretaceous origin.We created molecular phylogenies for this group, assigned each genus/family to the tectonic plate on which it is extant, and subjected the cladogram to areogram analysis. We also assessed ecological, mycotrophic and morphological traits, and global circulation patterns, as these might affect this group’s distribution.The initial analysis (omitting fossil evidence) showed that the crown of Dipterocarpaceae sl occurred concurrently on the South American and Madagascan plates. Including fossils from Africa and India changed this to a South American-African origin. Collectively, these origins represent NorthWest Gondwana with South America, Africa and Madagascar remaining conjoined until ≥105–115 Ma, setting the minimum age for this superclade with some evidence that it may be much older. We also show that the immediate ancestors of the three daughter lineages [Dipterocarpaceae- Sarcolaenaceae (in Africa/Madagascar, ≥115 Ma), Cistaceae- Pakaraimaea (South America/Africa/Eurasia, ≥105 Ma) and Bixaceae-Cochlospermum-Sphaerosepalaceae (South America/ Africa, ≥105 Ma)] also arose in NorthWest Gondwana.The immediate ancestors or basal species in Sarcolaenaceae, Sphaerosepalaceae, Dipterocarpaceae (both its subfamilies) and Bixaceae migrated from (South America)/Africa to Madagascar and we propose that the Dipterocarpoideae proceeded from Africa to India while still linked to Madagascar. In addition, much subsequent diversification of this superclade has occurred on the Eurasian, Indian, SE Asian (Sunda) and North American plates post-Gondwanan breakup.This long vicariant history is supported by fossil, ecological, mycotrophic and morphological traits, and global circulation patterns that show negligible propensity for transoceanic dispersal to explain this clade’s wide intercontinental distribution.We conclude that all these areocladogram/plate-breakup/ ecomorphological/circulation features are consistent with a Gondwanan/early-Cretaceous (>115 Ma) origin for the Dipterocarpaceae-Cistaceae-Bixaceae superclade plus its three daughter clades. Future analyses at the species level, exploring alternative diversification dates from both fossils and plate-tectonic dynamics, are needed to refine these findings.

Amphiboreality and Distribution of Snailfishes (Cottiformes: Liparidae) in the Arctic and the North Atlantic

The marine ichthyofauna of the Arctic Ocean has an ancestral origin from the Pacific Ocean and, to a lesser extent, from the Atlantic Ocean, which is explained by the amphiboreal concept, developed on groups of fish and invertebrates. Snailfishes (Liparidae) of the Arctic and the North Atlantic are analyzed in the context of this amphiboreal concept. The review is based on the data of many years of research on their taxonomy using various material of morphological differences/similarities of the taxa and patterns of species distribution against the background of biogeographic representations. For the Arctic area, 33 species of the family are known: Liparis (5), Careproctus (21), Paraliparis (2), Rhodichthys (2), and Psednos (3). For the Atlantic fauna, with the same number of species, their composition differs: Liparis (6), Careproctus (3), Paraliparis (12), Psednos (11), and Eutelichthys (1). The amphiboreal concept explains the speciation of Liparis and the majority of Careproctus as the result of trans-Arctic preglacial migrations. For other (deep-sea) species, the hypothesis of a transoceanic dispersal route is applicable; it passed from the North Pacific through the Southern Ocean and then north across the Atlantic.

A Review of the Giant Triton (Charonia tritonis), from Exploitation to Coral Reef Protector?

Charonia tritonis (Charoniidae), one of the largest marine gastropods and an echinoderm specialist, preys on Crown-of-Thorns starfish (CoTS), a recurring pest that continues to be a leading cause of coral mortality on Indo-Pacific reefs. Widespread historical exploitation has impacted their numbers, with standing populations considered rare throughout their habitat. Their life-stage attributes, i.e., teleplanic larvae, planktotrophic phase spanning years permitting transoceanic dispersal, and recruitment to coral reefs through oceanic influx with intense larval mortality, have likely hindered their recovery. Decline in numbers is hypothesised to account partially for periodic CoTS outbreaks, yet predator-prey dynamics between these two species that might influence this are poorly understood. The C. tritonis excretory secretome elicits a proximity deterrence effect on CoTS, the nature of which is under investigation as a possible tool in CoTS biocontrol scenarios. However, specificity and zone of impact in situ are unknown, and whether the mere presence of C. tritonis and/or predation pressure has any regulatory influence over CoTS populations remains to be established. The fundamental taxonomy and distinctive characteristics, biology and ecology of C. tritonis is summarized, and knowledge gaps relevant to understanding their role within coral reefs identified. Information is provided regarding exploitation of C. tritonis across its habitat, and prospects for conservation interventions, including captive rearing and stock enhancement to repopulate local regions, are discussed. Its predator-prey ecology is also examined and potential to mitigate CoTS considered. Recommendations to direct future research into this predator and for its inclusion in a CoTS integrated pest management strategy to improve coral reef health are offered.

Diversification dynamics of chameleons (Chamaeleonidae)

AbstractChameleons are charismatic and common lizards across Madagascar, Africa, and some surrounding regions. Little is known about their diversification dynamics and how this relates to their ecology, so we estimated diversification rate variation and consider this in the context of three hypotheses previously proposed in the literature. First, that the transoceanic dispersal from Africa to Madagascar on two separate occasions has resulted in fast radiation of Malagasy chameleons. Second, that the substantial floral turnover in their distributions within South Africa has resulted in rapid radiations of the endemic dwarf chameleons (Bradypodion). Finally, that the evolution of distinct ecomorphs of chameleon has fuelled fast diversification via adaptive radiations. We use the most recent and complete phylogeny of chameleons to estimate the diversification dynamics of the group using three methods: BAMM (which estimates constant or gradually changing diversification regimes and tests for shifts in these), MEDUSA (which tests for rate shifts in particular clades), and ClaDS (which estimates branch‐specific diversification rates). Our results from all analyses estimate a diversification rate increase in a clade containing most of the genusBradypodion, a group containing the South African dwarf chameleons which occur in recognized biodiversity hotspots in diverse habitats. We find no evidence for shifts resulting from dispersal events to Madagascar or related to the strong ecomorphological divergence of short‐tailed chameleon lineages (Brookesia,Palleon,Rhampholeon, andRieppeleon). The single burst of diversification within chameleons was in a clade which was associated with geographic areas which have experienced rapid habitat turnover and vicariance over the last ~10 million years. This suggests that ‘habitat vicariance’ resulting from ecological changes in vegetation has contributed to the diversity of species in this area by increasing diversification rates.

Extremely Stochastic Connectivity of Island Mangroves

Studies of mangrove population connectivity have focused primarily on global to regional scales and have suggested potential for long-distance connectivity, with archipelagos serving as stepping stones for trans-oceanic dispersal. However, the contribution of propagule dispersal to connectivity is still largely unknown, especially at local-scale. Identifying fine-scale propagule dispersal patterns unique to individual island systems is important to understand their contribution to global species distributions, and to select appropriate sizes and locations for mangrove conservation in archipelagos. Using population genetic methods and a release-recapture method employing GPS drifting buoys, we investigated the spatiotemporal scale of propagule dispersal of Rhizophora stylosa, one of the widely distributed mangrove species in the Indo-West Pacific. This study sought to quantify intra- and inter-island connectivity and to assess their contributions to oceanic scale dispersal of R. stylosa from the Ryukyu Archipelago, which spans over 545 km in southwestern Japan. Using 7 microsatellite markers, we tested 354 samples collected from 16 fringing populations on 4 islands. We identified 3 genetic populations, indicating distinct genetic structures comprising 3 distinguishable bioregions (genetic clusters). The western end of the archipelago receives relatively frequent migration (m > 0.1), but is genetically isolated from other sites. Based on genetic migration rates, we found that the central area of the archipelago serves as a stepping stone for southwestward, but not northeastward dispersal. On the other hand, with in-situ drifting buoys, we did not confirm prevailing dispersal directionality within the archipelago, instead confirming local eddies. Some buoys trapped in those eddies demonstrated potential for successful beaching from another island. A large portion of buoys were carried predominantly northeastward by the Kuroshio Current and drifted away from the coastal areas into the Pacific, contrary to local migrations. We found that the spatiotemporal scale of propagule dispersal is limited by the distance between islands (< 200km), propagule viability duration, and fecundity. Over all, recruitment does not occur frequently enough to unify the genetic structure in the archipelago, and the Ryukyu Archipelago is isolated in the center of the global mangrove distribution.

Termite dispersal is influenced by their diet.

Termites feed on vegetal matter at various stages of decomposition. Lineages of wood- and soil-feeding termites are distributed across terrestrial ecosystems located between 45°N and 45°S of latitude, a distribution they acquired through many transoceanic dispersal events. While wood-feeding termites often live in the wood on which they feed and are efficient at dispersing across oceans by rafting, soil-feeders are believed to be poor dispersers. Therefore, their distribution across multiple continents requires an explanation. Here, we reconstructed the historical biogeography and the ancestral diet of termites using mitochondrial genomes and δ13C and δ15N stable isotope measurements obtained from 324 termite samples collected in five biogeographic realms. Our biogeographic models showed that wood-feeders are better at dispersing across oceans than soil-feeders, further corroborated by the presence of wood-feeders on remote islands devoid of soil-feeders. However, our ancestral range reconstructions identified 33 dispersal events among biogeographic realms, 18 of which were performed by soil-feeders. Therefore, despite their lower dispersal ability, soil-feeders performed several transoceanic dispersals that shaped the distribution of modern termites.

Three dispersal routes out of Africa: A puzzling biogeographical history in freshwater planarians

AbstractAimFreshwater planarians may have a wide geographical range despite their assumed low vagility. Found across four continents, Dugesia may have either an ancient origin on a large palaeo landmass, followed by colonisation in different regions before continental fragmentation, or a more recent origin and subsequent transoceanic dispersal. We seek to resolve between these two hypotheses.LocationAfrica, Eurasia and Australasia.TaxonGenus Dugesia (Platyhelminthes: Tricladida: Dugesiidae).MethodsWe used data from the sequencing of six gene fragments and comprehensive taxonomic sampling of Dugesia from across its distribution range to reconstruct the phylogeny of this genus using maximum likelihood and bayesian inference methods. We conducted two phylogenetic dating analyses using Platyhelminthes fossils and palaeogeological events. Basing on the time‐calibrated molecular phylogenetic framework we evaluated the contribution of vicariance and dispersal to the biogeographical evolution of Dugesia. By reconstructing the ancestral areas and present‐day potential distribution using BioGeoBEARS and niche modelling, we elucidated the biogeographical history of the genus.ResultsThe present‐day distribution of Dugesia is a result of different vicariance and dispersal events. However, we also found evidence of transoceanic dispersal. Consistent with previous hypotheses, Dugesia dates to the Upper Jurassic in the Afro‐Malagasy Gondwana region. We unveiled a novel biogeographical scenario for the genus, involving multiple events of colonisation in Eurasia from continental Africa via at least three dispersal routes.Main conclusionsDugesia is an ancient genus having reached its present distribution through a complex history of dispersal and vicariant events following its origin in southern Gondwana. Despite the low vagility of Dugesia, we found evidence of their overseas dispersal.

A new species of Halorhynchus from Madagascar (Coleoptera, Curculionidae, Cossoninae, Onycholipini).

Halorhynchusremii Chamorro & Steiner, sp. nov. is described from Madagascar. This new species is the third known species of the genus and the first for Africa. Halorhynchusremii is compared to other psammophilous, anophthalmous onycholipine cossonines. Transoceanic dispersal between Australia and Madagascar and sand burrowing adaptation are briefly discussed. A key to the species is provided.