HISTORICAL BIOGEOGRAPHY IN THE INDO-PACIFIC: A CLADISTIC APPROACH

Abstract— The history of biogeographic theories about the Indo-Pacific is reviewed. The methods of cladistic biogeography are introduced and 10 monophyletic groups of Miridae (Insecta: Heteroptera) are used to apply these methods in the Indo-Pacific. The results are summarized and then combined with those of Duffels on cicadas. The results of most previous schemes are rejected on the basis of new results because the prior studies applied methods which failed to correctly interrelate areas of endemism within the Indo-Pacific and between this and other regions. The composite biotic nature of New Guinea is stressed.
"it is the presence in and not the absence from land areas of organisms that calls for reasoned explanations" (Evans, 1959)     

The mammals of northern Melanesia: speciation,ecology, and biogeography

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Connectivity and the development of population genetic structure in Indo‐West Pacific coral reef communities

Aim To identify connectivity patterns among coral reefs of the Indo‐West Pacific. Projecting connectivity forward in time provides a framework for studying long‐term source–sink dynamics in the region, and makes it possible to evaluate the manner in which migration shapes population genetic structure at regional scales. This information is essential for addressing critical gaps in knowledge for conservation planning efforts in one of the most biologically diverse regions on earth. Location Coral reefs of the Indo‐West Pacific, ranging from 15° S to 30° N and 95° E to 140° E. Methods Individual‐based biophysical dispersal models were used in conjunction with matrix projection to identify the expected patterns of exchange between coral reefs over time. Results Present‐day oceanographic conditions lead to the transport of larvae from the South China Sea into the Coral Triangle region via the Sulu Sea, and from northern Papua New Guinea and the Solomon Islands via Halmahera. The directionality of the system leads to the expected accumulation of organisms from outlying areas into the Coral Triangle region over time, particularly in the vicinity of the Maluku Islands and eastern Sulawesi. Coral reefs in Papua New Guinea, the Sulu Archipelago and areas within the Philippines are expected to be areas of high diversity as well. Main conclusions Biophysical dispersal models, used in conjunction with matrix projection, provide an effective means of simulating connectivity structure across the Indo‐West Pacific and thereby evaluating the directionality of genetic diversity. Migration appears to have a significant influence on population genetic structure in the region. Based on present‐day ocean currents, coral reefs in the South China Sea, northern Papua New Guinea and the Solomon Islands are contributing to high levels of diversity in the Coral Triangle.     

Cladistic analysis and biogeography of the cicadas of the Indo-Pacific subtribe Cosmopsaltriina (Hemiptera: Cicadoidea: Cicadidae)

Abstract A consensus cladogram is presented for ninety-seven of the ninety-nine (sub)species of the cicada subtribe Cosmopsaltriina on the basis of a cladistic analysis of forty-nine characters. The consensus cladogram confirms the monophyly of the eight genera constituting the subtribe, and the monophyly of the subtribe as a whole. Cosmopsaltriina occur in Sulawesi, the Moluccas, New Guinea, Cape York, the Solomon Islands, Vanuatu, Fiji, Tonga and Samoa. The subtribe demonstrates a high rate of endemism on genus, species group and species level. The taxon-area and consensus-area cladograms resulting from Brooks parsimony analysis are discussed in relation to the palaeogeography of the area.     

The endemic plant families and the palms of New Caledonia: a biogeographical analysis

This paper provides a panbiogeographical analysis of the endemic plant families and the palms of New Caledonia. There are three endemic plant families in New Caledonia and several genera that were previously recognized as endemic families. Of these taxa, some are sister to widespread Northern Hemisphere or global groups (Canacomyrica, Austrotaxus, Amborella). The others belong to trans‐Indian Ocean groups (Strasburgeria), trans‐tropical Pacific groups (Oncotheca) or Tasman Sea/Coral Sea groups (Phelline, Paracryphia) that are sister to widespread Northern Hemisphere or global groups. In palms, the four clades show allopatric regional connections in, respectively: (1) western Indonesia, Malaysia and Thailand; (2) Vanuatu/Fiji and the southern Ryukyu Islands near Taiwan; (3) the western Tasman/Coral Sea (eastern Australia, New Guinea and the Solomon Islands); and (4) the eastern Tasman/Coral Sea (Lord Howe and Norfolk Islands, New Zealand, Vanuatu, Fiji and the Solomon Islands). The four clades thus belong to different centres of endemism that overlap in New Caledonia. The patterns are attributed not to chance dispersal and adaptive radiation but to the different histories of the eight terranes that fused to produce modern New Caledonia. Trans‐tropical Pacific connections can be related to the Cretaceous igneous plateaus that formed in the central Pacific and were carried, with plate movement, west to the Solomon Islands and New Zealand, and east to Colombia and the Caribbean.     

An extended survey of the genetic polymorphism at the human coagulation factor XIII: a subunit structural locus

The distribution of the three previously reported alleles, with normal products at the factor XIII A subunit structural locus, FXIIIA*1, FXIIIA*2 and FXIIIA*4 has been studied in populations from the region extending from the Indonesian archipelago through Papua New Guinea, Australia and New Zealand to the Pacific Islands of Micronesia, Melanesia and Polynesia. In addition a population from the Caspian Littoral of Iran and a population of South American Indians were studied. The FXIIIA*1 and FXIIIA*2 alleles were polymorphic in all populations studied. The distribution of the FXIIIA*4 allele suggests that it may be a Melanesian marker.     

Tree diversity and phytogeographical patterns of tropical high mountain rain forests in Central Sulawesi,Indonesia

Tropical high mountain forests in Lore Lindu National Park, Sulawesi, Indonesia, were described by their floristic composition and the importance of tree families (Family importance values, FIV), based on tree inventories conducted on 4 plots (each 0.24 ha) in old-growth forest stands at c. 1800 and 2400 m a.s.l. (mid- and upper montane elevations). To identify general patterns and regional peculiarities of the forests in the SE Asian and SW Pacific context, the biogeography of the tree species was analysed using distribution records. Out of the total of 87 tree species, only 18 species were found at both elevational zones. The discovery of new species and new distribution records (28% of the data set) highlights the deficiencies in the taxonomic and distribution data for Sulawesi. Sulawesi endemism rate was 20%. In the mid-montane Fagaceae–Myrtaceae forests, Lithocarpus spp. (Fagaceae) were overall important (4 spp. occupying around half of the total basal area) and the Myrtaceae the most species rich (8 spp.), thus showing typical features of Malesian montane forests. The upper montane conifer-Myrtaceae forest contained several high mountain tree taxa and showed affinity to the forests of New Guinea. The mountain flora comprised both eastern and western Malesian elements, with the nearest neighbouring islands Borneo and Maluku both sharing species with Sulawesi, reflecting the complex palaeogeography of the island. A separate analysis showed the mid-montane forest to possess greatest biogeographical affinity to Borneo/western Malesia, and the upper montane forest had a number of typical elements of Papuasia/eastern Malesia and the Phillipines, which may be a result of historical patterns in land connection and the emergence of mountain ranges.     

Panbiogeography of New Caledonia,south‐west Pacific: basal angiosperms on basement terranes,ultramafic endemics inherited from volcanic island arcs and old taxa endemic to young islands

Aim To investigate areas of endemism in New Caledonia and their relationship with tectonic history. Location New Caledonia, south‐west Pacific. Methods Panbiogeographical analysis. Results Biogeographical patterns within New Caledonia are described and illustrated with reference to eight terranes and ten centres of endemism. The basement terranes make up a centre of endemism for taxa including Amborella, the basal angiosperm. Three of the terranes that accreted to the basement in the Eocene (high‐pressure metamorphic terrane, ultramafic nappe and Loyalty Ridge) have their own endemics. Main conclusions New Caledonia is not simply a fragment of Gondwana but, like New Zealand and New Guinea, is a complex mosaic of allochthonous terranes. The four New Caledonian basement terranes were all formed from island arc‐derived and arc‐associated material (including ophiolites) which accumulated in the pre‐Pacific Ocean, not in Gondwana. They amalgamated and were accreted to Gondwana (eastern Australia) in the Late Jurassic/Early Cretaceous, but in the Late Cretaceous they separated from Australia with the opening of the Tasman Sea and break‐up of Gondwana. An Eocene collision of the basement terranes with an island arc to the north‐east – possibly the Loyalty Ridge – is of special biogeographical interest in connection with New Caledonia–central Pacific affinities. The Loyalty–Three Kings Ridge has had a separate history from that of the Norfolk Ridge/New Caledonia, although both now run in parallel between Vanuatu and New Zealand. The South Loyalty Basin opened between Grande Terre and the Loyalty Ridge in the Cretaceous and attained a width of 750 km. However, it was almost completely destroyed by subduction in the Eocene which brought the Loyalty Ridge and Grande Terre together again, after 30 Myr of separation. The tectonic history is reflected in the strong biogeographical differences between Grande Terre and the Loyalty Islands. Many Loyalty Islands taxa are widespread in the Pacific but do not occur on Grande Terre, and many Grande Terre/Australian groups are not on the Loyalty Islands. The Loyalty Islands are young (2 Myr old) but they are merely the currently emergent parts of the Loyalty Ridge whose ancestor arcs have a history of volcanism dating back to the Cretaceous. Old taxa endemic to the young Loyalty Ridge islands persist over geological time as a dynamic metapopulation surviving in situ on the individually ephemeral islands and atolls found around subduction zones. The current Loyalty Islands, like the Grande Terre terranes, have inherited their biota from previous islands. On Grande Terre, the ultramafic terrane was emplaced on Grande Terre in the Eocene (about the same time as the collision with the island arc). The very diverse endemic flora on the ultramafics may have been inherited by the obducting nappe from prior base‐rich habitat in the region, including the mafic Poya terrane and the limestones typical of arc and intraplate volcanic islands.     

Traditional Banana Diversity in Oceania: An Endangered Heritage

This study aims to understand the genetic diversity of traditional Oceanian starchy bananas in order to propose an efficient conservation strategy for these endangered varieties. SSR and DArT molecular markers are used to characterize a large sample of Pacific accessions, from New Guinea to Tahiti and Hawaii. All Pacific starchy bananas are shown of New Guinea origin, by interspecific hybridization between Musa acuminata (AA genome), more precisely its local subspecies M. acuminata ssp. banksii, and M. balbisiana (BB genome) generating triploid AAB Pacific starchy bananas. These AAB genotypes do not form a subgroup sensu stricto and genetic markers differentiate two subgroups across the three morphotypes usually identified: Iholena versus Popoulu and Maoli. The Popoulu/Maoli accessions, even if morphologically diverse throughout the Pacific, cluster in the same genetic subgroup. However, the subgroup is not strictly monophyletic and several close, but different genotypes are linked to the dominant genotype. One of the related genotypes is specific to New Caledonia (NC), with morphotypes close to Maoli, but with some primitive characters. It is concluded that the diffusion of Pacific starchy AAB bananas results from a series of introductions of triploids originating in New Guinea area from several sexual recombination events implying different genotypes of M. acuminata ssp. banksii. This scheme of multiple waves from the New Guinea zone is consistent with the archaeological data for peopling of the Pacific. The present geographic distribution suggests that a greater diversity must have existed in the past. Its erosion finds parallels with the erosion of cultural traditions, inexorably declining in most of the Polynesian or Melanesian Islands. Symmetrically, diversity hot spots appear linked to the local persistence of traditions: Maoli in New Caledonian Kanak traditions or Iholena in a few Polynesian islands. These results will contribute to optimizing the conservation strategy for the ex-situ Pacific Banana Collection supported collectively by the Pacific countries.     

Austronesian Speakers and Hereditary Leadership in the Pacific

ABSTRACT

This article explores the notion that peoples speaking Austronesian languages brought the ideology of social hierarchy based on hereditary leadership into the Pacific Islands. This social model contrasts with the strongly egalitarian leadership that likely characterised peoples already residing in New Guinea and nearby islands. While complex interactions between these two groups did occur, particularly in coastal areas, the latter populations rarely adopted hierarchical models of leadership. In contrast, the institution of hereditary leadership burgeoned into elaborate chiefdoms as Austronesian speakers expanded into Remote Oceania. Using linguistic and archaeological evidence, we argue that hereditary leadership, or the institutions to support it, may already have been in place in early Austronesian societies in Taiwan. We further evaluate this correlation by reviewing ethnographic reports of chiefs and reanalysing scholarly appraisals of big-man societies and chiefdoms. We conclude that the ‘Melanesian big-man vs. Polynesian chief’ contrast corresponds largely to the Austronesian and Non-Austronesian language divide; attention to which can clarify the development of hereditary leadership in the Pacific and illuminate historical relations among cultures in Near Oceania.     

DISTRIBUTION AND DISPERSAL OF CENTRAL PACIFIC LESSER FRIGATEBIRDS ‘FREGATA ARZEL*

During the period from March 1963 to July 1965 the Pacific Ocean Biological Survey Program made an extensive study of the islands of the Central Pacific in the area bounded by 10°N.,180° W., 10° S. and 150° W. In the course of this study much new information was obtained on the distribution and dispersal of the Lesser Frigatebird. We have found that Lesser Frigatebirds are an abundant and widely distributed breeding bird in the Central Pacific, although only once previously reported breeding. Most of the young Lesser Frigatebirds from the Phoenix Islands travel to the Solomon Islands, Bismarck Archipelago, New Guinea, or the Philippines. A few travel farther north to the Ryukyu Islands, Japan, Taiwan, and Siberia, and a few also move to areas southwest and southeast of the Phoenix Islands. Most of the dispersal to these latter areas apparently occurs earlier than the dispersal to the Solomons. The dispersal pattern may be dependent in part on the surface wind pattern.     

Historical biogeography of Rhododendron section Vireya and the Malesian Archipelago

Aim Vireya rhododendrons are distinctive and easily recognizable by their general form; however, they are virtually circumscribed geographically, predominantly distributed throughout the biogeographically intriguing Malesian Archipelago. Hypotheses of the evolutionary relationships of the group have been proposed but the biogeography of vireyas has not been analysed based on molecular phylogeny. Recently, the first detailed molecular phylogenetic investigation of section Vireya was completed based on cp‐ and nrDNA sequence data, therefore making this cladistic biogeographic study of vireya rhododendrons possible. Location Malesia, Australia, Solomon Islands, Taiwan, Himalayas, north Vietnam and south China. Methods Based on distribution maps, areas of endemism were determined for the biogeographic region of Malesia. Area relationships were analysed based on a recent molecular phylogeny of species in section Vireya. The method of paralogy‐free subtree analysis was applied. Results Individual distribution maps were produced for 74 species of Rhododendron section Vireya. Species clades with bootstrap support proved to be biogeographically informative. Major clades correspond to three regions: eastern Malesia, western/middle Malesia and Taiwan/north Vietnam/south China. Within eastern Malesia, Australia, New Guinea, the Bismarck Archipelago and Solomon Islands are related. In western Malesia, northern Philippines, Borneo, southern Moluccas and north and west Sulawesi are related. These areas are more distantly related to Sumatra, the Malay peninsula, Java, Bali, Palawan, Lesser Sunda islands and the southern Philippines. The position of the Himalayas is equivocal and part of a basal polytomy in the summary area cladogram. Main conclusions Two alternative hypotheses are proposed for the evolution of vireya rhododendrons based on the pattern of area relationships. The first hypothesis is that the vireyas are an old group, with ancestors present on Gondwana, rifting north in the Cretaceous. The second alternative hypothesis is that vireyas are a young group that has dispersed eastwards from India to Australia and the Solomon Islands since the current Malesian islands formed.     

Phylogenetics of fanged frogs: testing biogeographical hypotheses at the interface of the asian and Australian faunal zones

The interface of the Asian and Australian faunal zones is defined by a network of deep ocean trenches that separate intervening islands of the Philippines and Wallacea (Sulawesi, the Lesser Sundas, and the Moluccas). Studies of this region by Wallace marked the genesis of the field of biogeography, yet few workers have used molecular methods to investigate the biogeography of taxa whose distribution spans this interface. Some taxa, such as the fanged frogs of the ranid genus Limnonectes, have distributions on either side of the zoogeographical lines of Wallace and Huxley, offering an opportunity to ask how frequently these purported barriers were crossed and by what paths. To examine diversification of Limnonectes in Southeast Asia, the Philippines, and Wallacea, we estimated a phylogeny from mitochondrial DNA sequences obtained from a robust geographic sample. Our analyses suggest that these frogs dispersed from Borneo to the Philippines at least twice, from Borneo to Sulawesi once or twice, from Sulawesi to the Philippines once, and from the Philippines to Sulawesi once. Dispersal to the Moluccas occurred from Sulawesi and to the Lesser Sundas from Java/Bali. Species distributions are generally concordant with Pleistocene aggregate island complexes of the Philippines and with areas of endemism on Sulawesi. We conclude that the recognition of zoogeographic lines, though insightful, may oversimplify the biogeography of widespread taxa in this region.     

Biogeography and diversification of the Pacific ant genus Lordomyrma Emery

Aim This study addresses the origins of terrestrial biodiversity of the Fijian islands using the ant genus Lordomyrma (Hymenoptera: Formicidae: Myrmicinae) as a model system. We derive the evolution of the genus and determine its closest extra-Fijian relatives from geological data, molecular phylogenetic reconstruction and divergence estimates. Location Ant taxa were sampled in the Southwest Pacific, Melanesia, Southeast Asia, Australia and mainland China. Methods Phylogeny and divergence estimates of the ant genus Lordomyrma based on four nuclear genes (28S, ArgK, LW Rh, CAD) plus data on Indo-Pacific geological history are used to address current hypotheses regarding the origins of the Fijian biota. Results The genus Lordomyrma probably originated in mainland Asia, with subsequent colonization of Australia and the Pacific. The Fijian Lordomyrma clade is monophyletic, and originated c. 8.8 Ma, when it diverged from a sister group in Papua New Guinea. Main conclusions The colonization of Fiji by Lordomyrma is probably a result of long-distance dispersal from New Guinea, possibly aided by island hopping across the Vitiaz Arc. The timeline of diversification in Lordomyrma is broadly congruent with the Miocene fragmentation of the Vitiaz Arc and the Pliocene emergence of Vanua Levu. The biotic shuttle hypothesis, which posits ‘Eua Island as the source of Fijian endemics, is rejected based on the sister relationship of Fiji and New Guinea lineages, as well as on the Miocene submergence of the terrane below sea level. The diversity of Fijian Lordomyrma results from the radiation of a single lineage, which diverged from a New Guinea sister group. The genus appears to have originated in Asia rather than in Australia.     

Vicariance biogeography and terrane tectonics in the South Pacific: analysis of the genus Abrotanella (Compositae)

The species of Abrotanella (Compositae) form mats and cushions a few centimetres high and up to a metre or more in diameter. The flowers are less complex than those of most Compositae and lack a pappus, the usual means of dispersal in the family. There are 20 species, all restricted to mountains of Australasia and southern South America. The putative affinities of Abrotanella involve several tribes of Compositae and the genus is not considered derived within the family. A comparative analysis of areas of endemism in Abrotanella shows clear patterns of vicariance and disjunction shared with many plants and animals, and longdistance dispersal is rejected as an explanation. Abrotanella and the three genera related to it are all restricted to lands bordering the Pacific. Areas previously accepted as areas of endemism, such as New Guinea, Tasmania, New Zealand and southern South America, are shown to be polyphyletic complexes, rather than simple areas. Use of such areas in area cladograms leads to the erroneous interpretation of taxa-area relations as incongruent. Distributions of the taxa in Abrotanella are correlated with tectonic features such as plate margins, transform faults and fracture zones, and processes such as continental rifting, terrane accretion, granite emplacement and orogeny. Abrotanellapatearoa sp. nov., a high-alpine cushion-plant, is described from mountains of eastern Central Otago: Rock and Pillar Range, Lammerlaw Range, Umbrella Mountains and Garvie Mountains.     

Signatures of invasion: using an integrative approach to infer the spread of melon fly, <Emphasis Type="Italic">Zeugodacus cucurbitae</Emphasis> (Diptera: Tephritidae), across Southeast Asia and the West Pacific

Invasion into new areas by already widespread pest organisms often occurs through non-obvious routes, with the origins of such invasions difficult to determine. Understanding population structure using multiple datatypes can help untangle past dispersal events and reveal putative contemporary invasion pathways. The tephritid fruit fly, Zeugodacus cucurbitae (Coquillett), is a serious pest of cucurbits and other commercial crops and is considered native to the Indo-Oriental region, but is invasive in both Africa and the Pacific. Here, we combine molecular (microsatellites and COI) and morphological (male genetalia length and wing shape geometric morphometrics) data within an integrative taxonomic framework to test hypotheses concerning levels of Z. cucurbitae population variation observed in Southeast Asia (native range, 10 sites, ~200 individuals) versus the West Pacific (invasive range, 4 sites, ~80 individuals), and whether single or multiple introductions of Z. cucurbitae have occurred into the West Pacific. We also use this case to explicitly test if using an integrative approach provides more information about hypothesized invasion pathways than either genetic or morphological approaches would do alone. All datasets support Z. cucurbitae as being more variable in Southeast Asia than the West Pacific, and within these regions populations appear to be structured geographically. In particular, mainland and Sundaic Southeast Asian locations formed separate clusters, and New Guinea and Solomon Islands were not closely related to Guam and Hawaii. Evidence supports a separate single origin for New Guinea from the Melanesian arc, the Solomon Islands from Malaysia/Singapore, and Guam from mainland Asia, but multiple introductions into Hawaii from mainland Asia. Taken together, we argue that there is great value in integrating evidence from multiple sources as it can provide finer resolution of population relationships than any single data source alone.     

Biogeography of Australasian flightless weevils (Curculionidae,Celeuthetini) suggests permeability of Lydekker's and Wallace's Lines

The Indo‐Australian region was formed by the collision of the Australian and Asian plates, and its fauna largely reflects this dual origin. Lydekker's and Wallace's Lines represent biogeographic transition boundaries between biotas although their permeability through geological times was rarely assessed. Here, we explore the evolutionary history of flightless weevils of the tribe Celeuthetini in this geologically highly complex region. We generated a DNA sequence data set of 2236 bp comprising two nuclear and two mitochondrial markers for 62 species of the Indo‐Australian tribe Celeuthetini. We used Bayesian Inference and Maximum Likelihood to reconstruct the first molecular phylogeny of the group. Based on this phylogenetic tree, we employed the program BioGeoBEARS to infer the biogeographical history of Celeuthetini in the region. The group's radiation begun east of Wallace's Line, probably during the mid‐Eocene. We unveil multiple transgressions of Lydekker's and Wallace's Lines mostly during the Miocene with a significant role of founder‐event speciation. The phylogeny of Celeuthetini is geographically highly structured with the first lineages occurring in New Guinea and the Moluccas, and a deep divergence between two clades largely confined to Sulawesi and their respective sister clades of the Lesser Sunda Islands. Wallace's Line was crossed once from Sulawesi and three times from the Lesser Sunda Islands to Java whilst Lydekker's Line was crossed once from New Guinea to the Moluccas. Although this beetle group shows extensive local diversification with little dispersal, the biogeographical demarcations of the Australasian region appear to have been rather porous barriers to dispersal.     

The impact of the Austronesian expansion: evidence from mtDNA and Y chromosome diversity in the Admiralty Islands of Melanesia

The genetic ancestry of Polynesians can be traced to both Asia and Melanesia, which presumably reflects admixture occurring between incoming Austronesians and resident non-Austronesians in Melanesia before the subsequent occupation of the greater Pacific; however, the genetic impact of the Austronesian expansion to Melanesia remains largely unknown. We therefore studied the diversity of nonrecombining Y chromosomal (NRY) and mitochondrial (mt) DNA in the Admiralty Islands, located north of mainland Papua New Guinea, and updated our previous data from Asia, Melanesia, and Polynesia with new NRY markers. The Admiralties are occupied today solely by Austronesian-speaking groups, but their human settlement history goes back 20,000 years prior to the arrival of Austronesians about 3,400 years ago. On the Admiralties, we found substantial mtDNA and NRY variation of both Austronesian and non-Austronesian origins, with higher frequencies of Asian mtDNA and Melanesian NRY haplogroups, similar to previous findings in Polynesia and perhaps as a consequence of Austronesian matrilocality. Thus, the Austronesian language replacement on the Admiralties (and elsewhere in Island Melanesia and coastal New Guinea) was accompanied by an incomplete genetic replacement that is more associated with mtDNA than with NRY diversity. These results provide further support for the "Slow Boat" model of Polynesian origins, according to which Polynesian ancestors originated from East Asia but genetically mixed with Melanesians before colonizing the Pacific. We also observed that non-Austronesian groups of coastal New Guinea and Island Melanesia had significantly higher frequencies of Asian mtDNA haplogroups than of Asian NRY haplogroups, suggesting sex-biased admixture perhaps as a consequence of non-Austronesian patrilocality. We additionally found that the predominant NRY haplogroup of Asian origin in the Admiralties (O-M110) likely originated in Taiwan, thus providing the first direct Y chromosome evidence for a Taiwanese origin of the Austronesian expansion. Furthermore, we identified a NRY haplogroup (K-P79, also found on the Admiralties) in Polynesians that most likely arose in the Bismarck Archipelago, providing the first direct link between northern Island Melanesia and Polynesia. These results significantly advance our understanding of the impact of the Austronesian expansion and human history in the Pacific region.     

Out of the Neotropics: Late Cretaceous colonization of Australasia by American arthropods

The origins of tropical southwest Pacific diversity are traditionally attributed to southeast Asia or Australia. Oceanic and fragment islands are typically colonized by lineages from adjacent continental margins, resulting in attrition of diversity with distance from the mainland. Here, we show that an exceptional tropical family of harvestmen with a trans-Pacific disjunct distribution has its origin in the Neotropics. We found in a multi-locus phylogenetic analysis that the opilionid family Zalmoxidae, which is distributed in tropical forests on both sides of the Pacific, is a monophyletic entity with basal lineages endemic to Amazonia and Mesoamerica. Indo-Pacific Zalmoxidae constitute a nested clade, indicating a single colonization event. Lineages endemic to putative source regions, including Australia and New Guinea, constitute derived groups. Divergence time estimates and probabilistic ancestral area reconstructions support a Neotropical origin of the group, and a Late Cretaceous (ca 82 Ma) colonization of Australasia out of the Fiji Islands and/or Borneo, which are consistent with a transoceanic dispersal event. Our results suggest that the endemic diversity within traditionally defined zoogeographic boundaries might have more complex evolutionary origins than previously envisioned.     

Historical biogeography of Melicope (Rutaceae) and its close relatives with a special emphasis on Pacific dispersals

The genus Melicope (Rutaceae) occurs on most Pacific archipelagos and is perfectly suited to study Pacific biogeography. The main goal was to infer the age, geographic origin and colonization patterns of Melicope and its relatives. We sequenced three nuclear and two plastid markers for 332 specimens that represent 164 species in 16 genera of Rutaceae. Phylogenetic reconstruction, molecular dating, ancestral area reconstruction and diversification analyses were carried out. The two main clades (Acronychia‐Melicope and Euodia) originated in Australasia and their crown ages are dated to the Miocene. Diversification rates differed among the subclades and were lowest in the Euodia lineage and highest in the Hawaiian Melicope lineage. The Malagasy and Mascarene species form a clade, which split from its SE Asian relatives in the Pliocene/Pleistocene. At least eight colonizations to the Pacific islands occurred. The timing of all colonizations except for the Hawaiian group is congruent with age of the island ages. Australia, New Guinea and New Caledonia have been the source of colonizations into the Pacific islands in the Melicope clade. Melicope shows high dispersability and has colonized remote archipelagos such as the Austral and Marquesas Islands each twice. Colonization of islands of the Hawaiian‐Emperor seamount chain likely predates the ages of the current main islands, and the initial colonization to Kaua'i occurred after the splitting of the Hawaiian lineage into two subclades. Wider ecological niches and adaptations to bird‐dispersal likely account for the much higher species richness in the Acronychia‐Melicope clade compared to the Euodia clade.