The Indochinese–Sundaic faunal transition at the Isthmus of Kra: an analysis of resident forest bird species distributions

Aim  To establish the geographical position of the biogeographical transition between Indochinese and Sundaic faunas using distributional data for the best-documented taxon, the birds.
Methods  Distributional data of 544 resident forest and forest edge bird species of Thailand and the Thai–Malay peninsula were examined at 45 sites spanning 15° of latitude from northern-most Thailand to the southern peninsular Malaysia. Sites were grouped into 23 degree or half-degree latitudinal zones and avifaunal similarity coefficients were calculated between each zone.
Results  A Mantel test revealed a significant transition between northern Indochinese and southern Sundaic (Indomalay) avifauna assemblages just north of the Isthmus of Kra (10°30' N). Northern and southern range limits of 152 species (> 269 species and subspecies combined) lie between 11° and 13° N.
Main conclusions  This transition between zoogeographical subregions is not coincident with the widely recognized transition between floristic provinces which is traditionally placed 400–500 km further south at the Kangar–Pattani line, but is associated with a change from wet seasonal evergreen dipterocarp rain forest to mixed moist deciduous forest north of the Isthmus of Kra in the northern Thai–Malay peninsula. Climatological and ecological factors associated with the distribution of forest types today are reviewed and it is hypothesized that the avian transition tracks the northern phytogeographical boundary. Palaeogeographical factors, including hypothetical Neogene seaways, which may account for the historical development of both phytogeographical and avifaunal transitions are also described.     

The Indochinese–Sundaic zoogeographic transition: a description and analysis of terrestrial mammal species distributions

Aim We describe the distributions of mammal species between the Indochinese and Sundaic subregions and examine the traditional view that the two faunas show a transition near the Isthmus of Kra on the Thai–Malay peninsula. Location Species distributions are described along a 2000‐km transect from 20° N (northernmost Thailand) to 1° N (Singapore). Methods For the 325 species of native non‐marine mammals occurring along the transect we used published records to provide a database of their distributional records by degree of latitude. Results Along the transect we found 128 Indochinese species with southern range limits, 121 Sundaic species with northern range limits, four un‐assignable endemics and 72 widespread species. In total, 152 southern and 147 northern range limits were identified, and their distribution provides no evidence for a narrow faunal transition near the Isthmus of Kra (10°30′ N) or elsewhere. Range limits of both bats and non‐volant mammals cluster in northernmost peninsular Malaysia (5° N) and 800 km further north, where the peninsula joins the continent proper (14° N). The clusters of northern and southern range limits are not concordant but overlap by 100–200 km. Similarly, the range limits of bats and non‐volant mammals cluster at slightly different latitudes. There are 30% fewer species and range limits in the central and northern peninsula (between 6 and 13° N), and 35 more widely distributed species have range gaps in this region. In addition, we found 70 fewer species at the southern tip of the peninsula (1° N) than at 3–4° N. Main conclusions The deficiencies of both species and species range limits in the central and northern peninsula are attributed to an area effect caused by repeated sea‐level changes. Using a new global glacioeustatic curve developed by Miller and associates we show that there were > 58 rapid sea‐level rises of > 40 m in the last 5 Myr that would have resulted in significant faunal compression and local population extirpation in the narrow central and northern parts of the peninsula. This new global sea‐level curve appears to account for the observed patterns of the latitudinal diversity of mammal species, the concentration of species range limits north and south of this area, the nature and position of the transition between biogeographical subregions, and possibly the divergence of the faunas themselves during the Neogene. The decline of species diversity at the southern end of the transect is attributed to a peninsula effect similar to that described elsewhere.     

Phylogeographic evidence for the existence of an ancient biogeographic barrier: the Isthmus of Kra Seaway

Biogeographic boundaries are characterised by distinct faunal and floral assemblages restricted on either side, but patterns among groups of taxa often vary and may not be discrete. Historical biogeography as a consequence, while providing crucial insights into the relationship between biological diversity and earth history, has some limitations. Patterns of intraspecific molecular variation, however, may show unambiguous evidence for such historical divides, and can be used to test competing biogeographic hypotheses (often based on the dispersal-vicariance debate). Here, we utilise this method to test the hypothesis that a major biogeographic transition zone between the Sundaic and Indochinese biotas, located just north of the Isthmus of Kra in SE Asia, is the result of Neogene marine transgressions that breached the Isthmus in two locations for prolonged periods of time (>1 million year duration). Phylogeographic analyses of a freshwater decapod crustacean, the giant freshwater prawn Macrobrachium rosenbergii, strongly supports the historical existence of the more northerly postulated seaway. Results presented here highlight the power of utilising intraspecific molecular variation in testing biogeographical hypotheses.     

基因组时代的新视野: 东南亚哺乳动物类群在第四纪冰河时期多样性的起源与分化

东南亚地区东起菲律宾群岛, 西至印度次大陆, 北及中国中部, 南至巽他群岛, 涵盖了世界上25个最重要的生物多样性热点地区之中的6个, 具有极其重要的全球生物多样性保护的战略意义。该地区复杂的地质地貌和气候历史使其动植物的种类和数量都极为丰富。经典的生物地理分界线华莱士线和克拉地峡将该地区进一步划分出包括部分巽他群岛和马来半岛在内的南部巽他区和北部印度支那区两个生物多样性热点地区。主要基于形态学的生物地理学研究认为巽他区和印度支那区通过马来半岛陆地相连, 并且第四纪大部分时间海平面下降形成大陆桥, 直到一万年前该地区的众多岛屿仍与大陆连接, 促进了哺乳动物的种群迁徙与基因交流, 因此物种种群间的差别将很细微。然而近来分子遗传学研究表明, 由于其他生态因素制约, 哺乳动物的迁移能力可能比以往认为的低, 大陆桥的存在并不一定导致迁徙的发生, 许多种群的隔离早在200万年前便已形成, 并且没有因为后来冰川期海平面降低而恢复种群交流, 而距今7.3万年前发生的苏门答腊多巴超级火山爆发也可能进一步影响了物种间和物种内多样性的形成和分化。通过已有的东南亚哺乳动物种群遗传学研究结果, 我们认为物种间或种群间的差异主要表现为三个层次: 巽他区种群与印度支那区种群间约百万年尺度的分化, 巽他区不同岛屿种群间约数十万年尺度的分化, 以及发生于晚更新世的分化事件。已有的东南亚种群遗传学研究主要采用线粒体及核基因多位点数据进行分析, 而种群基因组学分析则使得获得详尽的种群历史动态成为可能, 并使我们可以进一步了解东南亚哺乳动物类群所经历的物种形成过程。     

Sympatric Asian felid phylogeography reveals a major Indochinese–Sundaic divergence

The dynamic geological and climatological history of Southeast Asia has spawned a complex array of ecosystems and 12 of the 37 known cat species, making it the most felid‐rich region in the world. To examine the evolutionary histories of these poorly studied fauna, we compared phylogeography of six species (leopard cat Prionailurus bengalensis, fishing cat P. viverrinus, Asiatic golden cat Pardofelis temminckii, marbled cat P. marmorata, tiger Panthera tigris and leopard P. pardus) by sequencing over 5 kb of DNA each from 445 specimens at multiple loci of mtDNA, Y and X chromosomes. All species except the leopard displayed significant phylogenetic partitions between Indochina and Sundaland, with the central Thai–Malay Peninsula serving as the biogeographic boundary. Concordant mtDNA and nuclear DNA genealogies revealed deep Indochinese–Sundaic divergences around 2 MYA in both P. bengalensis and P. marmorata comparable to previously described interspecific distances within Felidae. The divergence coincided with serial sea level rises during the late Pliocene and early Pleistocene, and was probably reinforced by repeated isolation events associated with environmental changes throughout the Pleistocene. Indochinese–Sundaic differentiations within P. tigris and P. temminckii were more recent at 72–108 and 250–1570 kya, respectively. Overall, these results illuminate unexpected, deep vicariance events in Southeast Asian felids and provide compelling evidence of species‐level distinction between the Indochinese and Sundaic populations in the leopard cat and marbled cat. Broader sampling and further molecular and morphometric analyses of these species will be instrumental in defining conservation units and effectively preserving Southeast Asian biodiversity.     

Phylogeographic structure in mitochondrial DNA of a South-east Asian freshwater fish, Hemibagrus nemurus (Siluroidei; Bagridae) and Pleistocene sea-level changes on the Sunda shelf

We postulated that the biogeographical history of South-east Asia contributed to extensive admixture during Pleistocene low sea levels of genetic groups of an obligate freshwater fish (the river catfish, Hemibagrus nemurus) isolated during periods of high sea levels. During Pleistocene glacial maxima, the sea level was lower than at present and the islands of the Sunda shelf (Sumatra, Borneo and Java) and the Asian mainland were connected by lowlands traversed by rivers. Restriction fragment length polymorphisms in mitochondrial DNA were documented for 140 putative H. nemurus analysed from 13 sampling sites resulting in the definition of 35 haplotypes. The high level of haplotype differentiation (mean P × 100 = 2.22, SD = 1.33) indicates that the subdivision of the ancestral H. netnurus group was extensive and probably occurred early in the Pleistocene. The occurrence of some genetically divergent groups of the H. netnurus complex occurring in sympatry in widely separated locations supports the proposition that low sea levels aided the dispersion and mingling of genetic groups. Based on both genetic and morphological evidence, the main H. nemurus line gave rise to three regional groups: (1) a morphologically distinct ‘Indochinese’ group composed of two mtDNA clades overlapping in east peninsular Malaysia; (2) a ‘Sundaic’ group composed of various lineages of differing morphology and genetic identity; (3) a genetically distinct ‘Sarawak’ group in west Borneo, similar in morphology to the ‘Sundaic’ and ‘Indochinese’ groups, but including a small, golden colour morph as a distinct dade. The morphologically similar Sundaic forms from west Java, Sumatra and west Borneo show some degree of genetic divergence, but their phylogenetic relationships are poorly resolved. The most genetically and morphologically distinct Sundaic dade, assigned to H. hoevenii, colonized the Kapuas river (west Borneo), east Sumatra and south peninsular Malaysia. Contrary to our original hypothesis and present biogeographical theory, little exchange of genetic groups has apparently occurred between the mainland and the Sunda Islands during recent glaciations.     

The biogeography of the Isthmus of Kra region: a review

This review examines the evidence for a significant biogeographic divide on the Thai–Malay Peninsula of mainland southeast Asia (SE Asia) associated with the Isthmus of Kra. The divide is believed to be of the same scale as ‘Wallace’s Line’, though it remains less well‐known, less well‐studied, and its location and cause are enigmatic. This review presents relevant geological, geographical, climatic, biogeographic and sea‐level data, discusses some exemplar distributional patterns and concludes with an integrated discussion.     

Explaining the causes of the zoogeographic transition around the Isthmus of Kra: using bats as a case study

Aim  The causes of a zoogeographic divide in peninsular Thailand around the Isthmus of Kra have not been adequately resolved. We explored climatic, historical and geological perspectives to gain insights into factors that may have contributed to the development and maintenance of this zoogeographic transition, and to determine whether a faunal transition occurs for bats. Location  Southeast Asia, focusing on the Thai Peninsula. Methods  Spatial principal components analysis was used to determine the relationship between climate and species distribution patterns. We studied bats (order Chiroptera) because of their ability to bypass small‐scale geophysical barriers. Spatial data on bat species distributions on the Thai Peninsula were analysed in relation to multivariate measures of climate to determine the possible influence of climatic zonation on distribution patterns. We assessed the effects of the interaction of climatic zonation with the highly dynamic environmental conditions the area has undergone in relation to species distribution patterns. Results  A zoogeographic transition was found, with 44 species (out of 127) restricted to the north of the Isthmus of Kra and 29 restricted to the south, although there were relatively few abrupt changes in distribution at the exact position of the isthmus. Northern and southern species were associated with specific climatic conditions. Major transitions in the distribution of bat species exist at 6–6.5° N and 13–13.5° N, with a smaller peak at 11.0° N. These major peaks fall in the same areas as the borders of climatic zones, and the 6–6.5° N peak falls in the same area as a floristic divide (the Kangar–Pattani Line). Main conclusions  On the mainland, climatic zones cause gradual changes in species distributions. However, in addition to climatic factors, repeated changes in the breadth of the Sunda Shelf during recent glacial cycles may have caused locally high extinction rates at narrow points on the peninsula, exacerbating transitions in species distribution patterns along the region, in the context of a peninsula effect that reduces opportunities for recolonization.     

When Thailand was an island – the phylogeny and biogeography of mite harvestmen (Opiliones,Cyphophthalmi, Stylocellidae) in Southeast Asia

Aim To develop a comprehensive explanation for the biological diversity of Southeast Asia, especially in the Wallacea and Sundaland regions. This study focuses on a group of arachnids, mite harvestmen, which are thought to be an extremely old group of endemic animals that have been present in the region since most of its land supposedly formed part of the northern rim of the supercontinent Gondwana. Location Eastern Himalayas, Thai‐Malay Peninsula, Sumatra, Borneo, Java, Sulawesi, and New Guinea. Methods  Approximately 5.6 kb of sequence data were obtained from 110 South‐east Asian Cyphophthalmi specimens. Phylogenetic analyses were conducted under a variety of methods and analytical parameters, and the optimal tree was dated using calibration points derived from fossil data. Event based and paralogy‐free subtree biogeographical analyses were conducted. Results The Southeast Asian family Stylocellidae was recovered as monophyletic, arising on what is now the Thai‐Malay Peninsula and diversifying into three main clades. One clade (Meghalaya, here formally placed in Stylocellidae) expanded north as far as the eastern Himalayas, a second clade entered Borneo and later expanded back across the Sundaland Peninsula to Sumatra, and a third clade expanded out of Borneo into the entire lower part of Sundaland. Molecular dating suggested that Stylocellidae separated from other Cyphophthalmi 295 Ma and began diversifying 258 Ma, and the lineage that inhabits mostly Borneo today began diversifying between 175 and 150 Ma. Main conclusions The topology and molecular dating of our phylogenetic hypothesis suggest that Stylocellidae originated on Gondwana, arrived in Southeast Asia via the Cimmerian palaeocontinent, and subsequently diversified north, then south. Their present distribution in the Indo‐Malay Archipelago is explained largely by a diversification over the Sundaland Peninsula before western Sulawesi departed and the peninsula was extensively inundated.     

Mammals of south-east Asian islands and their Late Pleistocene environments

Aim The environments that existed in south‐east Asian islands during the last glacial are poorly known, limiting our understanding of mammalian biogeography in the region. The objective of this research is to investigate the ecological characteristics of mammal faunas on small islands, and to see whether the habitat requirements of the species in those faunas can be used to deduct the vegetation types that existed on islands before becoming isolated by rising sea levels. Location The maps presented here cover the small islands of tropical south‐east Asia, including the Burmese, Thai and Cambodian islands in the north, the islands off the coast of west Sumatra in the west, the islands around Java in the south, and the islands off the east coast of Borneo in the east, including the Philippine islands of Palawan and those in the Sulu Archipelago. Methods The presence records of mammal species on 215 small islands in the region were compiled, and the habitat requirements for each of these species was assessed (species that had probably been introduced by humans were excluded from the analysis). For each island location (longitude and latitude), maximum altitude of the island, total area, depth to nearest land, distance to nearest island, and distance to nearest mainland were assessed. Geographical and statistical analyses were used to investigate patterns of mammalian habitat requirements. Results The geographical analysis showed that forest‐dependent species, i.e. species that are only found in primary forest (lowland and mountainous), appear to be concentrated on islands off west Sumatra, in the Lingga and Riau Archipelagos, around Palawan, and around Bunguran Island; they are absent mostly from the islands of the Java Sea, those off the east coast of eastern Borneo, from most islands in the Sunda Strait, several islands in the northern South China Sea, and from all islands off the west coast of the Malay/Thai Peninsula and in the Gulf of Thailand. Species that generally occur outside primary forest, that is those in secondary forest, gardens, plantations and open areas mostly occurred on islands where the forest‐dependent species were absent. The statistical analysis showed that latitude and size of islands were important factors that determined the absence and presence of forest‐dependent species on small islands. Main conclusions The data suggest that during the last glacial there were several areas in the Sundaic region that remained forest covered: west of Sumatra, north‐west of Borneo, the Malacca Straits and around Palawan. Other areas may have been covered by more open vegetation types like tree savanna, or open deciduous forest: on and to the east of the Malay/Thai Peninsula, the Java Sea area, including the Sunda Strait, and eastern Borneo.     

Phylogeny of Cerberus (Serpentes: Homalopsinae) and phylogeography of Cerberus rynchops: diversification of a coastal marine snake in Southeast Asia

Aim The biogeography of Southeast Asia has been greatly affected by plate tectonic events over the last 10 Myr and changing sea levels during the Quaternary. We investigated how these events may have influenced the evolution of Cerberus Cuvier, a marine coastal snake belonging to the Homalopsinae (Oriental‐Australian Rear‐fanged Water Snakes). This study is an expansion of a previous study on the biogeography and systematics of Cerberus. Location We obtained species from localities across the range of the widely distributed Cerberus: India, Sri Lanka, the Andaman islands, Myanmar, the Philippines, Borneo, Suluwesi, Sumatra, Vietnam, Thailand, Singapore and Australia. Methods We analysed mtDNA sequences (12S, ND3, ATPase, 2338 nucleotide characters) from 21 localities. The sample consisted of 65 Cerberus rynchops (Schneider), three Cerberus australis (Gray) and four Cerberus microlepis Boulenger. One Homalopsis buccata (Linnaeus), one Bitia hydroides Gray, one Enhydris enhydris (Schneider), and two Enhydris plumbea (Boie) were used as outgroups. Results We produced phylogenetic trees based on parsimony, maximum likelihood and Bayesian analysis. We did not find unambiguous support for the monophly of Cerberus. Cerberus austalis, H. buccata and all other Cerberus populations formed a three‐way basal polytomy under parsimony and C. australis formed the sister group to a clade consisting of H. buccata and all other Cerberus in likelihood and Bayesian analysis. The non‐Australian Cerberus were monophyletic and consisted of four primary biogeographical clades: Indian and Mayanmar, Philippines, Greater Sunda Islands and Suluwesi, and the Thai‐Malay peninsula and Gulf of Thailand. The range of genetic divergence between these clades and Australian Cerberus was 0.06–0.12. Genetic divergence among clades to the west of Australia was less pronounced (Thai‐Malay peninsula and Gulf of Thailand = 0.02–0.05; Sunda Islands and Suluwesi = 0.02–0.05; Philippines = 0.02–0.06; India and Myanmar = 0.04–0.06, Philippines = 0.02–0.5). Main conclusions Gyi [University of Kansas Publications, Museum of Natural History 20 (1970), 47] recognized three species of Cerberus: C. australis (from Australia), C. microlepis (known only from Lake Buhi in the Philippines), and the widely distributed C. rynchops (India to Wallacea). We did not find strong support for the monophyly of the genus. Cerberus australis is highly divergent from all other Cerberus lineages sampled from this region. The geographically widespread C. rynchops is resolved into four biogeographical clades (Indian and Myanmar, Philippines, Greater Sunda Islands and Suluwesi, and the Thai‐Malay Peninsula and Gulf of Thailand). We discuss how the dispersal biology of a salt‐water tolerant, coastal marine taxon and the complex geological history of the region (Tertiary plate tectonic movements and Quaternary sea‐level changes) could produce the observed patterns of diversification.     

The influence of the ecological characteristics of phytocoenoses on the percentage proportions of zoogeographical elements in the malacocoenoses of land snails (Mollusca: Gastropoda terrestria)

The influence of 11 forest phytocoenoses in a single area (the Medvednica Mountain in north-western Croatia) on the composition of the zoogeographical elements of the land malacofauna was analysed. It was established that malacocoenoses in different plant associations of the same phytogeographical and zoogeographical area have different compositions in respect to the zoogeographical elements of the land snail fauna. Zoogeographical elements located on borders of the range display the widest divergences in their percentage representation in the malacocoenoses of the forest phytocoenoses of a single area. This is due to varying ecological conditions in the phytocoenoses under investigation.Abbreviations as. = association - subas.= subassociation     

Pleistocene and Holocene rhinocerotids (Mammalia,Perissodactyla) from the Indochinese Peninsula

Rhinocerotids were abundant and diverse in southern Asia during the Pleistocene and the Holocene epochs, as shown by palaeontological and archaeological discoveries published throughout the last century, whereas the only living rhinoceros in the Indochinese Peninsula is Rhinoceros sondaicus (Cat Loc Reserve, Vietnam). The Pleistocene-Holocene Indochinese rhinocerotid record consists of the extinct species Dicerorhinus gwebinensis (Early Pleistocene, Myanmar) and representatives of the Recent Asian Species Rhinoceros unicornis (Middle-Late Pleistocene), R. sondaicus (Middle Pleistocene-Recent), and Dicerorhinus sumatrensis (Middle Pleistocene-Holocene). This fossil record is synthesized, mapped for Early/Middle/Late Pleistocene and Holocene/Recent times, and then compared with coeval rhinocerotid assemblages from the adjacent areas (South China), subregions (Indian, Sundaic, Philippine, and Wallacean), and region (Palearctic), from a biochronological and biogeographical perspective.     

Late Pleistocene to Holocene distributional stasis in scorpions along the Baja California peninsula

The biota of the Baja California peninsula (BCP) assembled in response to a complex history of Neogene tectonics and Quaternary climates. We constructed species distribution models (SDMs) for 13 scorpion species from the BCP to compare current suitable habitat with that at the latest glacial maximum about 21 000 years ago. Using these SDMs, we modelled climatic suitability in relation to latitude along the BCP. Our SDMs suggested that most BCP scorpion distributions have remained remarkably conserved across the latest glacial to interglacial climatic transformation. Three areas of climatic suitability coincide remarkably well with genetic discontinuities in other co‐distributed taxa along the BCP, indicating that long‐term persistence of zones of abrupt climatic transition offer a viable alternative, or synergistic enhancement, to hypotheses of trans‐peninsular seaways as drivers of peninsular divergences. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111 , 450–461.     

Heterochrony: The evolution of ontogeny. By Michael L. McKinney and Kenneth J. McNamara. New York: Plenum Press. 1991. XIX + 437 pp. ISBN 0-306-43638-8. $ 49.50 (cloth)

Macaca fascicularis is broadly distributed in Southeast Asia across 30° of latitude and 35° of longitude (Indochinese Peninsula, Isthmus of Kra, Malay Peninsula, Greater and Lesser Sunda Islands, Philippine Islands, and numerous small, neighboring islands). The range is divisible into 1) a core area comprised of mainland Southeast Asia, Borneo, Sumatra, and Java (large land masses interconnected during the last glacial maximum, 18,000 B. P.); 2) shallow-water fringing islands, which are smaller islands connected to the core area during the last glacial maximum; and 3) deep-water fringing islands, which are peripheral islands not connected to the core area during the last glacial maximum. Skull length was used to study effects of latitude and insularity on patterns of size variation. The data are from 802 adult M. fascicularis specimens from 140 core-area localities, 63 shallow-water islands, and 29 deep-water islands. Sex-specific polynomial regressions of skull length on latitude were used to describe skull length variation in the core area. These regressions served as standards for evaluating variation among samples from shallow-water and deep-water islands. The core area exhibits Bergmannian latitudinal size clines through most of the species range. Thus, skull length decreases from about 8°S (Java) to the equator (Sumatra and Borneo), then increases as far north as about 13°N (Isthmus of Kra). Farther north, to the northernmost Indochinese localities at about 17°N, skull length in M. fascicularis decreases with increasing latitude, contrary to Bergmann's rule. Latitudinal size variation in shallow-water fringing islands generally parallels that in the core area. However, skull length tends to be smaller than in the core area at similar latitudes. Deep-water fringing islands are markedly more variable, with relatively small specimens in the Lesser Sunda Islands and relatively large specimens in the Nicobar Islands. These analyses illustrate how a primate species may vary in response to latitudinal temperature variation and to isolation. © 1993 Wiley-Liss, Inc.     

Are Chilean coastal forests pre‐Pleistocene relicts? Evidence from foliar physiognomy,palaeoclimate, and phytogeography

Aim We ask whether contemporary forests of the Chilean Coastal Range can be considered to be direct and conservative descendants of pre‐Pleistocene palaeofloras that occurred in southern South America from the Palaeogene to early Neogene periods (65–10 Ma), maintaining foliar physiognomies that do not match their present‐day climate. We also identify the most likely ancestors of present‐day coastal forests. Location Coastal Range of south‐central Chile (33–40° S). Methods We compared leaf morphology between five representative modern floras from mid‐latitude forests of the Chilean Coastal Range, and 14 Palaeogene–early Neogene palaeofloras from southern South America. We also compared the composition of biogeographical elements (defined by the modern distribution of plant genera) between fossil and present‐day assemblages. Palaeoclimatic reconstructions were based on a canonical correspondence analysis between leaf morphology of modern assemblages and eight climatic variables, and tested by a Monte Carlo permutation test. We compared the relative positions of fossil and modern floras on the environmental vector space defined by Canoco, and on axes defined by instrumental and estimated temperature and precipitation data. Results According to foliar characters, Palaeogene palaeofloras were strikingly divergent from present‐day coastal forests of central Chile. In contrast, two extant forest floras of the Chilean Coastal Range have a foliar morphology that resembles some late Eocene to early Miocene mixed palaeofloras, at least 23 Myr older. These two modern sites are representative of an area of the Coastal Range (36–37° S) that has been highlighted for its relictual character. None of the 14 fossil floras corresponded exactly to the modern composition of phytogeographic elements, although correspondence analyses showed that mixed and Neogene subtropical fossil floras were compositionally close to the extant woody floras of coastal forests in central Chile. Main Conclusions Contemporary forests of the Chilean Coastal Range exhibit strong physiognomic resemblance to the mixed palaeofloras from 33°57′ to 41°15′ S, which may be the closest ancestor of the deciduous and endemic‐rich Maulino forest, presently restricted to coastal areas between 36° and 38° S. In turn, the Neogene subtropical palaeoflora that occurred in the Proto‐Andean foothills of central Chile is the likely predecessor of Mediterranean‐type sclerophyllous forests of central Chile (32–33° S). Despite foliar resemblance between the late pre‐Pleistocene and extant forest floras, our palaeoclimatic reconstructions suggest that modern assemblages exist under climatic conditions that do not match their foliar physiognomy. We attribute this convergence in foliar morphology to the ‘evolutionary inertia’ of surviving lineages, favoured by the buffering effect of the coastal environment on climatic variability.     

A phytogeographical characterization of the vine flora of the Sonoran and Chihuahuan deserts

Aim This study presents a phytogeographical characterization of the vine flora of two lower North American desert regions as a biogeographical framework for further ecological inquiry into desert vines. Location The phytogeography of the vine flora of the Sonoran and Chihuahuan Deserts was c haracterized based on 263 known species. Methods Checklists of the vines of each desert were developed. Represented genera were then grouped into 10 phytogeographical elements based on worldwide distribution patterns. To compare the floristic composition of the desert floras, an index of species similarity was calculated. Results About a third more species of vines occur in the Sonoran Desert than in the Chihuahuan Desert. Based on the analysis, cosmopolitan genera are the only group more numerous in absolute terms in the Chihuahuan Desert than in the Sonoran Desert. Tropical elements are represented in about the same proportion in each desert as the number of species, however, nearly twice as many pantropical and neotropical genera are represented in the Sonoran Desert as in the Chihuahuan Desert. Proportionately, more genera of temperate elements occur in the Chihuahuan Desert than in the Sonoran desert, although the absolute number of genera is slightly higher in the latter. Main conclusions As these deserts are relatively recent ecological formations and as vines evolved in forest ecosystems, the composition of the desert vine floras is the result of the interaction between historical vegetation types, their constituent taxa and climatic and geological history. The main differences in the vining floras of the present‐day Sonoran and Chihuahuan Deserts appear to be the result of greater historical influence in the Sonoran Desert of (1) tropical vegetation types and (2) the emergence of the Gulf of California. The Chihuahuan Desert vine flora seems to be the result of (1) a more pronounced historical temperate vegetation, (2) the lack of an important isolating event, such as the creation of the Baja California peninsula, and (3) a cooler climate with shorter growing seasons.     

Geographical distributions in tropical trees: can geographical range predict performance and habitat association in co‐occurring tree species?

Aim A major floristic and climatic transition from aseasonal to seasonal evergreen tropical forest (the Kangar–Pattani Line; KPL) exists in the Indo‐Sundaic region of Southeast Asia. Mechanisms constraining species distribution here are at present poorly understood, but it is hypothesized that species differ in their tolerances of abiotic factors, in particular water availability. Under this hypothesis, we anticipate differences in performance or habitat preferences, or both, of species differing in distribution with respect to the KPL. The aim of this study is to test whether geographical distributions can be used to explain variation in growth, mortality and habitat preferences in co‐occurring tree species differing in their distribution in relation to the KPL. Location Pasoh Forest Reserve, Negeri Sembilan, Malaysia; south of the KPL. Methods All tree species within a 50‐ha forest dynamics plot were classified as widespread or southern based upon their distributions in relation to the KPL and as habitat specialists or generalists based on spatial association with soil‐based habitat categories. Growth and mortality rates, variation in growth and mortality with respect to soil type, and levels of habitat association were quantified for species with different geographical distributions. Results Differences existed in species performance based upon geographical distributions. Specifically, widespread species had lower growth rates than did species restricted to the aseasonal forests. Mortality rates did not differ as a function of geographical distribution. The growth responses of species to soil habitats also diverged, such that differences in performance of widespread species among soil types were more conservative than those of species restricted in their distribution to the aseasonal forests. However, the proportion of species showing positive habitat associations did not differ significantly between widespread and southern species. Main conclusions Distribution‐based differences in species performance and response to soil type support the hypothesis that species tolerant of wider climatic variation perform less well in any given environment due to limitations on plasticity. These performance differences provide quantitative evidence of the role of climatic transitions in determining tree species distributions in relation to the Kangar–Pattani Line in the Indo‐Malay region. Such differences in performance have important implications for our understanding of biodiversity gradients and responses of Indo‐Sundaic forests to climate change.     

Low genetic diversity in the masked palm civet Paguma larvata (Viverridae)

The masked palm civet is distributed through south-east Asia, China and the Himalayas. Because of its potential role in the severe acute respiratory syndrome (SARS) epidemic, it has become important to gather information on this species, and notably to provide a tool to determine the origin of farm and market animals. For this purpose, we studied the genetic variability and the phylogeographic pattern of the masked palm civet Paguma larvata . First, two portions of mitochondrial genes, cytochrome b and the control region, were sequenced for a total of 76 individuals sampled from China, the Indochinese region and the Sundaic region. Results indicated a low genetic variability and suggested a lack of a phylogeographic structure in this species, which do not allow inferring the geographic origin of samples of unknown origin, although it is possible to distinguish individuals from China and the Sundaic region. This low variation is in contrast to the well-marked morphological differentiation between the populations in the Sundaic and Chinese–Indochinese regions. We also used five microsatellite loci to genotype 149 samples from two wild and four farmed populations in China, where the masked palm civet is farmed and where the SARS coronavirus was isolated. These analyses also showed a reduced variability in Chinese civets and showed that farmed populations did not exhibit a lower genetic diversity than wild populations, suggesting frequent introductions of wild individuals into farms.     

Neogene sloth assemblages (Mammalia,Pilosa) of the Cocinetas Basin (La Guajira,Colombia): implications for the Great American Biotic Interchange

We describe sloth assemblages from the Cocinetas Basin (La Guajira peninsula, Colombia), found in the Neogene Castilletes and Ware formations, located in northernmost South America, documenting otherwise poorly known biotas. The tentative referral of a specimen to a small megatherioid sloth, Hyperleptus?, from the early–middle Miocene Castilletes Formation, suggests affinities of this fauna with the distant Santa Cruz Formation and documents a large latitudinal distribution for this taxon. The late Pliocene Ware Formation is much more diverse, with five distinct taxa representing every family of ‘ground sloths’. This diversity is also remarkable at the ecological level, with sloths spanning over two orders of magnitude of body mass and probably having different feeding strategies. Being only a few hundred kilometres away from the Isthmus of Panama, and a few hundred thousand years older than the classically recognized first main pulse of the Great American Biotic interchange (GABI 1), the Ware Formation furthermore documents an important fauna for the understanding of this major event in Neogene palaeobiogeography. The sloths for which unambiguous affinities were recovered are not closely related to the early immigrants found in North America before GABI 1.