Significance The effect of glacial cycles on Southeast Asian (SEA) rainforest during the Quaternary is unresolved. Some historical evidence suggests rainforests were confined to small refugia during ...glacial maxima, but dynamic vegetation models suggest evergreen rainforests were widespread. Because Dipterocarpaceae dominate current SEA rainforests, their distributions closely reflect general rainforest extent. Here, we use an extensive georeferenced database of collection records for 317 Dipterocarpaceae species to model their climatic niches, based on current climatic conditions. These distribution models were then hindcast onto historical climatic conditions of the last glacial maximum. The results indicate that central Sundaland, exposed because of lower sea levels at glacial maxima, harbored suitable environmental conditions for Dipterocarpaceae and was probably covered by rainforest.
The extent of Dipterocarp rainforests on the emergent Sundaland landmass in Southeast Asia during Quaternary glaciations remains a key question. A better understanding of the biogeographic history of Sundaland could help explain current patterns of biodiversity and support the development of effective forest conservation strategies. Dipterocarpaceae trees dominate the rainforests of Sundaland, and their distributions serve as a proxy for rainforest extent. We used species distribution models (SDMs) of 317 Dipterocarp species to estimate the geographic extent of appropriate climatic conditions for rainforest on Sundaland at the last glacial maximum (LGM). The SDMs suggest that the climate of central Sundaland at the LGM was suitable to sustain Dipterocarp rainforest, and that the presence of a previously suggested transequatorial savannah corridor at that time is unlikely. Our findings are supported by palynologic evidence, dynamic vegetation models, extant mammal and termite communities, vascular plant fatty acid stable isotopic compositions, and stable carbon isotopic compositions of cave guano profiles. Although Dipterocarp species richness was generally lower at the LGM, areas of high species richness were mostly found off the current islands and on the emergent Sunda Shelf, indicating substantial species migration and mixing during the transitions between the Quaternary glacial maxima and warm periods such as the present.
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The region of Tropical Southeast Asia and the Malay Archipelago is a very appealing area for research due to its outstanding biodiversity, being one of the most species‐rich areas in the world with ...high levels of endemism, and due to its complex geological history. The high number of species in tribe Dissochaeteae (Melastomataceae) and their tendency to narrow endemism make the tribe an ideal group for examining biogeographic patterns. We sampled 58 accessions spread over 42 accepted and two undescribed species of the Dissochaeteae. Two nuclear (ETS, ITS) and four chloroplast regions (ndhF, psbK‐psbL, rbcL, rpl16) were used for divergence time estimation and ancestral area reconstruction. Results from the molecular dating analysis suggest that the diversity of Dissochaeteae in the Southeast Asian region resulted from a South American ancestor in the late Eocene. The ancestor of the Dissochaeteae might have migrated from South America to Southeast Asia via North America and then entered Eurasia over the North Atlantic land bridge during the Eocene. The origin and early diversification of the Dissochaeteae in Southeast Asia dates back to the middle Oligocene, and most of the genera originated during the Miocene. Indochina and Borneo are most likely the area of origin for the most recent common ancestor of the Dissochaeteae and for many of the early diverging clades of some genera within Southeast Asia.
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FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
The genus Phyllanthus is paraphyletic as currently circumscribed, with the genera Breynia, Glochidion and Synostemon nested within it. A phylogeny based on nuclear (ITS, PHYC) and chloroplast (matK, ...accD‐psaI, trnS‐trnG) markers is presented, including 18/18 subgenera and 53/70 sections. Differences in habit, branching type, floral and fruit characters are discussed, and we find indications for shifts in pollination and dispersal strategies possibly underlying the convergent evolution of these characters in multiple clades. Several taxonomic issues were found in the subgeneric classification of Phyllanthus that will require new transfers and rank changes. Phyllanthus subg. Anesonemoides, subg. Conami, subg. Emblica, subg. Gomphidium, subg. Kirganelia and subg. Phyllanthus are polyphyletic, and several sections appear to be paraphyletic (e.g., P. sect. Anisonema, sect. Emblicastrum, sect. Pseudoactephila, sect. Swartziani, and sect. Xylophylla); P. subg. Phyllanthodendron is furthermore paraphyletic with the genus Glochidion nested within. To create a classification of tribe Phyllantheae that comprises exclusively monophyletic taxa, it is necessary to treat several clades at the same taxonomic rank as the genera Breynia, Glochidion and Synostemon. Since combining all genera would lead to one giant heterogeneous genus that is difficult to define, we recommend dividing Phyllanthus into several monophyletic genera, which have previously been recognized and often possess diagnostic (combinations of) morphological characters. This new classification is forthcoming.
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Several groups within tribe Phyllantheae (Phyllanthaceae) formed, independently, an (obligate) pollination mutualism with
moths, which originally had been parasitic. In this pollination system, ...female moths actively collect pollen from staminate flowers and deposit it on the stigma of pistillate flowers, after which they place at least one egg in or against the ovary. The high pollination rate makes the system beneficial for the plants, whereas the larvae are provided with food (part of the developing seeds) and some protection against predation. Qualitative comparisons are made between non-moth-pollinated lineages, used as outgroups and various, independently moth-pollinated Phyllantheae clades, used as ingroups, thereby looking for parallel developments. The flowers of both sexes of various groups display similar, convergent morphological adaptations to the pollination system, likely to secure the obligate relationship and to improve efficiency. Sepals in both sexes, free or partly to highly connate, are commonly upright and form a narrow tube. The staminate flowers often have united, vertical stamens with the anthers along the androphore or on top of the androphore. Pistillate flowers generally reduce the stigmatic surface, either by making the stigmas shorter or by uniting them into a cone with a small opening at the top for pollen deposition. Less obvious is the reduction of the stigmatic papillae; these are often present in non-moth-pollinated taxa, but absent in the moth-pollinated species. The most diverging, parallel adaptations to moth pollination are currently found in the Palaeotropics, whereas in the Neotropics, some groups continue to also be pollinated by other insect groups and are morphologically less changed.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Ficus subsection Urostigma as currently circumscribed contains 27 species, distributed in Africa, Asia, Australia and the Pacific, and is of key importance to understand the origin and evolution of ...Ficus and the fig-wasp mutualism. The species of subsection Urostigma are very variable in morphological characters and exhibit a wide range of often partly overlapping distributions, which makes identification often difficult. The systematic classification within and between this subsection and others is problematic, e.g., it is still unclear where to classify F. amplissima and F. rumphii. To clarify the circumscription of subsection Urostigma, a phylogenetic reconstruction based on four nuclear DNA markers (ITS, ETS, G3pdh, and ncpGS) combined with morphology and leaf anatomy is conducted. The phylogenetic tree based on the combined datasets shows that F. madagascariensis, a Madagascan species, is sister to the remainder of subsect. Urostigma. Ficus amplissima and F. rumphii, formerly constituting sect. Leucogyne, appear to be imbedded in subsect. Conosycea. The result of the phylogenetic analysis necessitates nomenclatural adjustments. A new classification of Ficus subsection Urostigma is presented along with the morphological and leaf anatomical apomorphies typical for the clades. Two new species are described ─ one in subsect. Urostigma, the other in Conosycea. One variety is raised to species level.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Aim: Using a dated phylogenetic hypothesis with nearly complete species-level sampling of Ficus subsect. Urostigma with several samples per species, spatiotemporal diversification patterns are ...clarified, and alternative hypotheses for repeated Palaeotropical intercontinental disjunctions (PIDs) are revisited. Location: (Sub) tropics of Africa, Madagascar, Asia and Australia. Methods: Estimates of divergence times were obtained using a Bayesian relaxed clock analysis via the program BEAST with three calibration points. The output was used to analyse the historical biogeographical patterns via the program RASP (S-DIVA option). The results were compared with existing geological knowledge. Results: The subsection probably originated in Madagascar or Madagascar and India, and dispersed once (or twice) to Africa and once to Asia (1st PID). From Asia the taxa dispersed all over Southeast Asia and finally to the west Pacific. Wallace's Line was relatively recently crossed several times independently by widespread species. One dispersal event back from Asia to Africa is inferred (2nd PID). Main conclusions: The combination of dates and area optimizations for the ancestral nodes of Ficus subsect. Urostigma agree with the tectonic history of the various areas and divergence dates published for Ficus. The first PID is explained by species rafting on India to Asia, after which the majority of species evolved in Asia-Australia. The second PID probably involved dispersal from India via south Asia and Arabia to Africa in the early Miocene before the world-wide climate cooled down and areas became drier. Dispersal over Wallace's Line is by widespread species from which only a few local endemics in east Malesia-Australia developed. The biogeographical history of F. subsect. Urostigma supports a complex picture of several crossings of PIDs and it confirms that the route between Asia and Africa via south Asia and Arabia is often favoured. This route was available during a long period from Oligocene to mid-Miocene and perhaps even up to 2 Ma.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
The problem of polymorphism in the
Calamus javensis
complex has been examined by various techniques in several publications. A wide range of morphological variation was identified during these ...studies. Characters showing high variation were leaf sheath and ocrea morphology, number and arrangement of leaflets, length and arrangement of the rachillas. All names used in the complex are here regarded as synonyms of
C. javensis
except
C. tenompokensis
, which is retained as a distinct species. One variety is recognized,
C. javensis
var.
polyphyllus
(including
C. acuminatus
). Using morphological characters, we recognized 11 informal (often not monophyletic) forms within
C. javensis
var.
javensis
. Here we present identification keys, descriptions and notes of all recognisable forms, varieties and species included in the
Calamus javensis
complex.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Aim The historical biogeography of three Palaeotropical legume genera, Aganope, Brachypterum and Derris, was investigated with the aim of (1) evaluating competing hypotheses on the origins of ...Palaeotropical intercontinental disjunctions (PIDs), and (2) inferring spatio-temporal diversification patterns in tropical Southeast Asia. Location Palaeotropics. Methods Plastid (trnL–F IGS, psbA–trnH IGS and trnK–matK ORF) and nuclear ribosomal (ITS/5.8S) DNA sequence data, covering the geographical distribution of all three genera, were analysed using an uncorrelated-rates relaxed molecular clock model. Ancestral areas were reconstructed using a likelihood approach implementing the dispersal–extinction/mcladogenesis model (Lagrange) and a Bayesian approach to dispersal–vicariance analysis (S-DIVA). Results A wide ancestral distribution in Africa and Asia was inferred for the Aganope stem and crown groups, with a vicariance event between Africa and Asia in the early Miocene. The Southeast Asian mainland was inferred as the ancestral area for both the Brachypterum and the Derris crown groups. The reconstructions indicated numerous dispersal events westwards to India, and eastwards across Wallace's Line to New Guinea from the middle Miocene onwards. Two dispersal events from Asia to Africa, in the Miocene–Pliocene in Brachypterum and in the Pliocene–Pleistocene in Derris, were deduced. Main conclusions The PID in Aganope is likely to be the result of vicariance, caused by climatic deterioration subsequent to the Middle Miocene Climatic Optimum. The inferred PIDs in Brachypterum and Derris in the middle Miocene to Pliocene–Pleistocene are consistent with long-distance dispersal. The biogeographical patterns of Brachypterum and Derris are similar to patterns identified in other Southeast Asian plant taxa, and highly congruent with geological events in Southeast Asia facilitating dispersal from the early Miocene onwards. Preadaptation to several environmental conditions and habitats including mangrove swamps, and high dispersal capabilities by hydrochory may explain the wide distributions of some species and frequent dispersal across oceanic water bodies separating western and eastern Malesia.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Aim: The dated phylogeny of Breynia (including Sauropus) was used to analyse historical biogeographical patterns and to compare the speciation events with tectonic occurrences and biotic and abiotic ...aspects. Location: Southeast Asia, Malesia and Australia. Methods: Existing molecular markers (trnS-trnG ,accD-psal, PHYC and ITS) were used in BEAST to make a Bayesian age estimate with an exponential relaxed molecular clock. The resulting cladograms and maximum clade credibility (MCC) tree were used as input in statistical dispersal-vicariance analysis (S-DIVA option in the RASP package). Results: Breynia originated 25-20 Ma in Thailand (western part of northern to southern Thailand) up to peninsular Malaysia. Dispersal occurred in various directions (India+Sri Lanka, China+Indochina, Malesia+Australia) establishing widespread species. Most species evolved locally in the area of origin and a relatively high number of species form limestone endemics. Main conclusions: There is little correlation between tectonic movements and dispersal patterns in Breynia. Only the dispersal over Wallace's Line occurred when stepping stones were in place. Speciation, especially in the area of origin seems to be linked to soil (limestone endemics) and pollination, as indicated by the presence of deviating inflorescences in B. subgen. Sauropus (no pollinators are known yet) and the obligate moth pollination in B. sect. Breynia.Moreover, B. sect. Breynia and three widespread species of B. subgen. Sauropus have (more) fleshy fruits and all these taxa generally have wide distributions, probably because of bird dispersal.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Macaranga and Mallotus (Euphorbiaceae s.s.) are two closely related, large paleo(sub)tropical genera. To investigate the phylogenetic relationships between and within them and to determine the ...position of related genera belonging to the subtribe Rottlerinae, we sequenced one plastid (trnL-F) and three nuclear (ITS, ncpGS, phyC) markers for species representative of these genera. The analyses demonstrated the monophyly of Macaranga and the paraphyly of Mallotus and revealed three highly supported main clades. The genera Cordemoya and Deuteromallotus and the Mallotus sections Hancea and Oliganthae form a basal Cordemoya s.l. clade. The two other clades, the Macaranga clade and the Mallotus s.s. clade (the latter with Coccoceras, Neotrewia, Octospermum, and Trewia), are sister groups. In the Macaranga clade, two basal lineages (comprising mostly sect. Pseudorottlera) and a crown group with three geographically homogenous main clades were identified. The phylogeny of the Mallotus s.s. clade is less clear because of internal conflict in all four data sets. Many of the sections and informal infrageneric groups of Macaranga and Mallotus do not appear to be monophyletic. In both the Macaranga and Mallotus s.s. clades, the African and/or Madagascan taxa are nested in Asian clades, suggesting migrations or dispersals from Asia to Africa and Madagascar.
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