A preliminary analysis of distribution patterns in a large, pantropical genus, Barleria L. (Acanthaceae)

Barleria L. (Acanthaceae) is a large, polymorphic, widespread genus of herbs and shrubs comprising about 300 species, occurring mainly in Africa and Asia but with one species, Barleria oenotheroides Dum.Cours., extending to the New World tropics. Recent completion of a monographic infra-generic classification of the genus (in which seven sections are recognised, and the names of four of these validated in this paper—see Appendix 1), has facilitated a comprehensive analysis of distribution patterns on a global scale. The richest representation of Barleria is in Africa where there are two centres of diversity, one in tropical East Africa (about eighty species) and the other in southern Africa (about seventy species). The number of species tails off rapidly to both the Far East and the West. Barleria shows a marked trans-Atlantic disjunction between West Africa and the Neotropics, with B. oenotheroides shared by these two regions. This type of disjunction, which is known in other genera of the family, cannot be adequately explained in Barleria on the basis of long-distance dispersal or past continental movements. There is a high degree of regional endemism (e.g. 75% for the Indian subcontinent) at both the species and sectional levels within this genus. The degree of similarity between regions is correspondingly low. The endemics in each region tend to belong to only one or a few of the sections. There are few truly widespread taxa within the genus. East and West Africa are the only regions in which all sections are represented. Sections Barleria and Prionitis C.B. Cl. are the most widespread in the genus; Sections Somalia (Oliv.) Lindau, Fissimura M. Balkwill and Stellatohirtae M. Balkwill are mainly restricted to Africa and Sections Chrysothrix M. Balkwill and Cavirostrata M. Balkwill are the most restricted, occurring mainly in India and Sri Lanka. On a local scale, many of the species show highly restricted, clumped distributions; this is apparently related to particular soil types and possibly to the short-distance, ballistic mode of seed dispersal. This account of the biogeography of Barleria is to be regarded as preliminary, as much taxonomic work at the species level remains to be done before a full-scale cladistic biogeographic account can be undertaken. Particular areas worthy of future investigation include establishing the centre of origin of the genus and investigating the basis for the high degree of endemism shown by many of the species.     

Review of plant biogeographic studies in Brazil

Molecular phylogenetic studies have become a major area of interest in plant systematics, and their impacts on historical biogeographic hypotheses are not to be disregarded. In Brazil, most historical biogeographic studies have relied on animal phylogenies, whereas plant biogeographic studies have largely lacked a phylogenetic component, having a limited utility for historical biogeography. That country, however, is of great importance for most biogeographic studies of lowland tropical South America, and it includes areas from a number of biogeographic regions of the continent. Important biogeographic reports have been published as part of phylogenetic studies, taxonomic monographs, and regional accounts for small areas or phytogeographic domains, but the available information is subsequently scattered and sometimes hard to find. In this paper we review some relevant angiosperm biogeographic studies in Brazil. Initially we briefly discuss the importance of other continents as source areas for the South American flora. Then we present a subdivision of Brazil into phytogeographic domains, and we cite studies that have explored the detection of biogeographic units （areas of endemism） and how they are historically related among those domains. Examples of plant taxa that could be used to test some biogeographic hypotheses are provided throughout, as well as taxa that exemplify several patterns of endemism and disjunction in the Brazilian angiosperm flora.     

山东省特有植物的研究

本文对山东省特有植物的区系组成、地理分布和特有性质进行了初步研究,并绘制了特有植物分布图。76种特有植物隶属于32科53属,其中蕨类植物5科8属12种,被子植物27科45属64种。这些特有植物多为新特有种而缺乏古特有种。特有植物的区系特征可以归纳为以下几点:(一)区系成分不算丰富;(二)地理分布极不均衡,有四个明显的特有现象中心,即昆嵛山,泰山、崂山和蒙山;(三)地理成分复杂。     

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.     

Ribosomal DNA evidence and disjunctions of western American Portulacaceae

Phylogenetic analysis of ribosomal DNA internal transcribed spacer sequences from 35 members of western American Portulacaceae plus seven Portulacaceae outgroups generally supports morphologically based interpretations of multiple intercontinental disjunctions. The data neither support nor refute monophyly of the western American group but strongly support a group comprising the western American taxa plus Phemeranthus, the only strictly American genus of the morphology-based eastern American/African group of Portulacaceae, along with the Australian genus Parakeelya. Support is strong for the monophyly of Calandrinia, Montiopsis, Lewisia, Claytonia, and Montia, along with a sister relationship of the last two. The data neither strongly support nor refute the morphologically based diagnosis of Cistanthe, but they strongly support a clade including the North American Cistanthe section Calyptridium and the South American Cistanthe sections Amarantoideae and Philippiamra. The internal transcribed spacer data fail to resolve the phylogenetic relationships among most of the western American lineages, suggesting either rapid radiation or, alternatively, erratic evolution of the internal transcribed spacer. The internal transcribed spacer and morphological evidence together suggest that in this group there have been 8-13 dispersal and colonization events across >2000 km (1 for every 15-26 extant species in this group). The internal transcribed spacer data document complex molecular evolutionary patterns, including strong substitution biases, among-site rate heterogeneity, positional bias for deamination-type substitutions, nonstationarity, and variable rates of insertion/deletion. Our phylogenetic conclusions, however, do not appear to be sensitive to these patterns.     

The North American obligate cave fauna: regional patterns

The obligate cave faunas of nine regions of the United States –Florida Lime Sinks, Appalachians, Interior Low Plateaus, Ozarks, Driftless Area,Edwards Aquifer/Balcones Escarpment, Guadalupe Mountains, Black Hills, andMother Lode – are described and compared. The number of aquatic(stygobitic) species ranged from zero (Black Hills) to 82 (Appalachians), andthe number of terrestrial (troglobitic) species ranged from zero (Florida LimeSinks) to 256 (Interior Low Plateau). Even at the level of genus, overlapbetween regions is low. Several predictor variables (karst area, number ofcaves, number of long caves, number of deep caves, distance from the Pleistoceneice margin, distance from the late Cretaceous Sea, and vegetation type – asurrogate for productivity) were assessed using rank order statistics,especially rank order multiple regression with a backward elimination procedure.For both stygobites and troglobites, only number of caves was a significantpredictor. The absence of a karst area effect suggested that the degree of karstdevelopment is better described by the number of caves rather than area ofkarst. There was no evidence that distance to Pleistocene glacial boundaries wasimportant, but there was some support for the importance of distance from late Cretaceous sea margins, a potential source of aquatic subterranean colonists. Finally,there was no indication that surface productivity had an effect on speciesrichness. Analysis was complicated by correlations among predictor variables.     

“金虎尾路线”植物的花进化与传粉转变

以金虎尾科植物地理分布格局及迁移历史总结出来的“金虎尾路线”, 是解释热带植物洲际间断分布与长距离扩散格局的重要模式。金虎尾路线阐明了金虎尾科植物历史时期7次独立的从起源中心(南美洲)向旧世界(非洲和亚洲)的洲际长距离扩散事件。本文总结了金虎尾路线植物起源地与扩散地主要类群的花部特征与传粉系统, 以探讨这些类群及类似植物长距离扩散后的花进化与传粉转变等适应规律。金虎尾科的南美洲类群都有分泌油脂的萼片腺体, 花的形态结构非常保守, 是与美洲当地特有的条蜂科集油蜂长期协同进化的结果。金虎尾科的非洲类群花保守性消失, 花白色、辐射对称且无萼片腺体, 繁育系统为雄花-两性花异株(功能性的雌雄异株), 传粉者是采集花粉的蜜蜂科昆虫。亚洲的一些属发生了类似非洲类群的泛化适应转变, 但风筝果属(Hiptage)出现了镜像花、异型雄蕊和极度反折的花瓣, 且传粉者是亚洲特有的大蜜蜂(Apis dorsata), 显示出了非常特化的适应性转变。风筝果属所在支系的现存类群涵盖了南美洲、中美洲、非洲和亚洲等地的地方特有属, 体现了金虎尾路线整个迁移历史过程, 是认识金虎尾路线及其进化适应规律的关键类群, 值得在今后的研究中加以重视。     

A new species of Elpidium (Crustacea,Ostracoda) from bromeliads in Cusuco National Park,Honduras

Passively dispersing aquatic invertebrates such as Ostracoda in restricted aquatic habitats such as bromeliads remain an intriguing observation considering the highly specialised dispersal vectors needed for efficient colonisation. Here we describe a new species of Elpidium, Elpidium merendonense sp. n., collected from bromeliads in the cloud forest from Cusuco National Park, Honduras. Elpidium merendonense sp. n. is a small to medium-sized species that can be easily distinguished from its congeners by its unique outgrowth at the posterior end of the left valve, visible especially in females. The species was common all through the park occurring at a wide range of altitudes and in different species of bromeliads. This finding is the first freshwater ostracod species described from Honduras and is in agreement with the prediction that the genus Elpidium contains a large number of species with small geographic distributions. We update the list of described species of Elpidium and present a key to species.     

New Caledonia: a very old Darwinian island?

New Caledonia has generally been considered a continental island, the biota of which largely dates back to Gondwanan times owing to its geological origin and the presence of phylogenetic relicts. This view is contradicted by geological evidence indicating long Palaeocene and Eocene submersions and by recent biogeographic and phylogenetic studies, with molecular or geophysical dating placing the biota no older than the Oligocene. Phylogenetic relicts do not provide conclusive information in this respect, as their presence cannot be explained by simple hypotheses but requires assumption of many ad hoc extinction events. The implication of this new scenario is that all the New Caledonian biota colonized the island since 37 Ma Local richness can be explained by local radiation and adaptation after colonization but also by many dispersal events, often repeated within the same groups of organisms. Local microendemism is another remarkable feature of the biota. It seems to be related to recent speciation mediated by climate, orography, soil type and perhaps unbalanced biotic interactions created by colonization disharmonies. New Caledonia must be considered as a very old Darwinian island, a concept that offers many more fascinating opportunities of study.     

Animal‐mediated long‐distance dispersals and migrations shaping the intercontinental disjunctions of Celastrus (Celastraceae) among five continents

The mechanisms underlying the origin, evolution, and distributional patterns of organisms are a major focus of biogeography. Vicariance and long‐distance dispersal (LDD) are two important explanations for disjunctive distribution patterns among lineages. In‐depth biogeographic studies of taxa that exhibit wide‐ranging disjunctions can provide valuable information for addressing the relative importance of these biogeographic mechanisms. The genus Celastrus contains ca. 30 species that are disjunctly distributed in five continents of both the Northern and Southern Hemispheres, providing an excellent system for historical biogeographic analyses. Here, we used sequence data from five markers (nuclear external transcribed spacer and internal transcribed spacer, and plastid psbA‐trnH, rpl16, and trnL‐F) to reconstruct the phylogeny of Celastrus and investigate its phylogenetic relationships with Tripterygium, estimate clade divergence times using the fossil‐calibrated method, and infer its ancestral distribution range. Celastrus and Tripterygium were each supported as monophyletic. The morphology‐based classification systems were not supported by the phylogenetic results. The divergence time between Celastrus and Tripterygium was estimated to be 26.22 Ma (95% highest posterior density: 24.46–28.17 Ma), and the diversification of Celastrus were suggested to be linked to global warming events during the Miocene. Celastrus was suggested to have a tropical Asian origin, and dispersed to Central and South America, North America, Oceania, and Madagascar at different periods, most probably through LDD. Birds may have facilitated transoceanic migrations of Celastrus because of its bicolored fruits, which contain red and fleshy arils. Our results highlight the importance of key morphological innovations and animal‐mediated dispersals for the rapid diversification of plant lineages across vast distributional ranges.     

Effects of habitat patchiness and connectivity on the spatial ecology of the root vole Microtus oeconomus

1. The effect of habitat patchiness and connectivity on dispersal distances and spatial aggregation of individuals is investigated in 12 enclosed populations of the root vole, Microtus oeconomus , employing a factorial experimental design with three different patch configurations and two distinct geographical root vole strains. The three patch configurations, all with an identical total area, were: two large patches, six small patches and six small patches connected by corridors.
2. The populations were followed for three generations (13. weeks) using live-trapping. Matrilineal relationships, time and place of birth, and weekly home ranges were established for the 1155 individuals in the study.
3. Smaller patch sizes enhanced dispersal, but most for one of the strains. The strain difference is, tentatively, explained by inbreeding avoidance which is known to differ between the strains.
4. The effect of habitat configuration on the dispersion pattern was similar for the two strains. Increased patchiness increased the aggregation of individuals. The two sexes diverged in their response, however, females being more aggregated than males.
5. The spatial pattern of matrilinearity was used as an indication of the resulting effect of habitat configuration on the demic structure in space. Patchiness enhanced and connectivity decreased the substructuring.