National Museum of the Philippines

Padre Burgos, Philippines

National Museum of the Philippines

Padre Burgos, Philippines
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Blackburn D.C.,University of Kansas | Bickford D.P.,National University of Singapore | Diesmos A.C.,National Museum of the Philippines | Iskandar D.T.,Bandung Institute of Technology | Brown R.M.,University of Kansas
PLoS ONE | Year: 2010

Background: The complex history of Southeast Asian islands has long been of interest to biogeographers. Dispersal and vicariance events in the Pleistocene have received the most attention, though recent studies suggest a potentially more ancient history to components of the terrestrial fauna. Among this fauna is the enigmatic archaeobatrachian frog genus Barbourula, which only occurs on the islands of Borneo and Palawan. We utilize this lineage to gain unique insight into the temporal history of lineage diversification in Southeast Asian islands. Methodology/Principal Findings: Using mitochondrial and nuclear genetic data, multiple fossil calibration points, and likelihood and Bayesian methods, we estimate phylogenetic relationships and divergence times for Barbourula. We determine the sensitivity of focal divergence times to specific calibration points by jackknife approach in which each calibration point is excluded from analysis. We find that relevant divergence time estimates are robust to the exclusion of specific calibration points. Barbourula is recovered as a monophyletic lineage nested within a monophyletic Costata. Barbourula diverged from its sister taxon Bombina in the Paleogene and the two species of Barbourula diverged in the Late Miocene. Conclusions/Significance: The divergences within Barbourula and between it and Bombina are surprisingly old and represent the oldest estimates for a cladogenetic event resulting in living taxa endemic to Southeast Asian islands. Moreover, these divergence time estimates are consistent with a new biogeographic scenario: the Palawan Ark Hypothesis. We suggest that components of Palawan's terrestrial fauna might have "rafted" on emergent portions of the North Palawan Block during its migration from the Asian mainland to its present-day position near Borneo. Further, dispersal from Palawan to Borneo (rather than Borneo to Palawan) may explain the current day disjunct distribution of this ancient lineage. © 2010 Blackburn et al.

Scheffers B.R.,National University of Singapore | Scheffers B.R.,James Cook University | Phillips B.L.,James Cook University | Laurance W.F.,James Cook University | And 3 more authors.
Proceedings of the Royal Society B: Biological Sciences | Year: 2013

Biodiversity is spatially organized by climatic gradients across elevation and latitude. But do other gradients exist that might drive biogeographic patterns? Here, we show that rainforest's vertical strata provide climatic gradients much steeper than those offered by elevation and latitude, and biodiversity of arboreal species is organized along this gradient. In Philippine and Singaporean rainforests, we demonstrate that rainforest frogs tend to shift up in the rainforest strata as altitude increases. Moreover, a Philippine-wide dataset of frog distributions shows that frog assemblages become increasingly arboreal at higher elevations. Thus, increased arboreality with elevation at broad biogeographic scales mirrors patterns we observed at local scales. Our proposed 'arboreality hypothesis' suggests that the ability to exploit arboreal habitats confers the potential for larger geographical distributions because species can shift their location in the rainforest strata to compensate for shifts in temperature associated with elevation and latitude. This novel finding may help explain patterns of species richness and abundance wherever vegetation produces a vertical microclimatic gradient. Our results further suggest that global warming will 'flatten' the biodiversity in rainforests by pushing arboreal species towards the cooler and wetter ground. This 'flattening' could potentially have serious impacts on forest functioning and species survival. © 2013 The Author(s) Published by the Royal Society. All rights reserved.

Ding H.-H.,CAS South China Botanical Garden | Ding H.-H.,University of Chinese Academy of Sciences | Chao Y.-S.,Kaohsiung Medical University | Callado J.R.,National Museum of the Philippines | Dong S.-Y.,CAS South China Botanical Garden
Molecular Phylogenetics and Evolution | Year: 2014

In this study we provide a phylogeny for the pantropical fern genus Tectaria, with emphasis on the Old World species, based on sequences of five plastid regions (atpB, ndhF plus ndhF-trnL, rbcL, rps16-matK plus matK, and trnL-F). Maximum parsimony, maximum likelihood, and Bayesian inference are used to analyze 115 individuals, representing ca. 56 species of Tectaria s.l. and 36 species of ten related genera. The results strongly support the monophyly of Tectaria in a broad sense, in which Ctenitopsis, Hemigramma, Heterogonium, Psomiocarpa, Quercifilix, Stenosemia, and Tectaridium should be submerged. Such broadly circumscribed Tectaria is supported by the arising pattern of veinlets and the base chromosome number (x= 40). Four primary clades are well resolved within Tectaria, one from the Neotropic (T. trifoliata clade) and three from the Old World (T. subtriphylla clade, Ctenitopsis clade, and T. crenata clade). Tectaria crenata clade is the largest one including six subclades. Of the genera previously recognized as tectarioid ferns, Ctenitis, Lastreopsis, and Pleocnemia, are confirmed to be members in Dryopteridaceae; while Pteridrys and Triplophyllum are supported in Tectariaceae. To infer morphological evolution, 13 commonly used characters are optimized on the resulting phylogenetic trees and in result, are all homoplastic in Tectaria. © 2014 Elsevier Inc.

Stevenson J.,Asia Pacific College | Siringan F.,University of the Philippines at Diliman | Finn J.,Asia Pacific College | Madulid D.,National Museum of the Philippines | Heijnis H.,Australian Nuclear Science and Technology Organisation
Global Change Biology | Year: 2010

The last 7000 years of environmental history for Paoay Lake and its surrounding landscape is examined through the analysis of pollen, diatoms, charcoal, mineral magnetics and AMS dating. Basal sediments contain shells of Cerithiidae and the saline-tolerant diatom Diploneis indicating that this was an estuarine environment before becoming a freshwater lake after 6000 bp. Pollen analysis shows that submontane forests, characterized by Pinus pollen, underwent a major disturbance around 5000 years ago, recovering to previous levels by 1000 years ago. Charcoal as an indicator of fire is abundant throughout record, although the highest levels occur in the earlier part of the record, between 6500 and 5000 years ago. An aspect of the project was to examine whether there is evidence of land clearance and agricultural development in the region during the late Holocene. While a clear signal of human impact in the record remains equivocal, there appears to be a correspondence between submontane forest decline and mid-Holocene ocean data that depict warmer and possibly drier conditions for the region. The study highlights the vulnerability of these montane forests to forecasts of a warmer and drier climate in the near future. © 2009 Blackwell Publishing Ltd.

Linkem C.W.,Biodiversity Research Center | Hesed K.M.,Biodiversity Research Center | Hesed K.M.,University of Maryland University College | Diesmos A.C.,National Museum of the Philippines | Brown R.M.,Biodiversity Research Center
Molecular Phylogenetics and Evolution | Year: 2010

In the megadiverse conservation hotspot of the Philippines, biodiversity is not uniformly distributed throughout the archipelago, but hierarchically partitioned into islands and island groups that were conjoined during the mid- to late-Pleistocene. Few species groups are widely distributed throughout the archipelago, but some exceptions exist, such as the common scincid lizards of the Sphenomorphus jagori complex (including S. jagori, S. coxi, and S. abdictus). Using mtDNA haplotype data we test biogeographic and taxonomic predictions in these abundant, large-bodied, forest floor lizards and arrive at conclusions that differ significantly from both past, and current, appraisals of species diversity. In contrast to expectations based on existing taxonomy (three species, each with two subspecies), we find evidence of at least eleven highly divergent species lineages diagnosed by haplotypic variation. Each lineage corresponds to a biogeographically circumscribed distribution (i.e., isolated islands or geological components of islands), suggesting lineage cohesion and allopatric differentiation. Parametric bootstrapping tests reject taxonomic and biogeographic hypotheses and suggest a complex pattern of unpredicted relationships. Only one of the former species (S. jagori) appears as a monophyletic entity (including four allopatric, highly divergent lineages that we suspect may represent evolutionary species), and the remaining species are paraphyletic, necessitating a comprehensive future taxonomic revision. The pattern of biogeographic provincialism and hidden cryptic species diversity detected here leads us to suspect that even the most common, presumably well-studied, and widespread species complexes in the Philippines are in need of thorough analysis with modern genetic and phylogenetic techniques. Such studies of speciation genetics in these common, widely distributed groups may lead to a better understanding of the genetic underpinnings of biodiversity, allow for an enhanced appreciation of the evolutionary history of this model island archipelago, and enable more informed conservation planning in a global biodiversity hotspot. © 2010 Elsevier Inc. All rights reserved.

Detroit F.,French Natural History Museum | Corny J.,French Natural History Museum | Corny J.,University of Ferrara | Dizon E.Z.,National Museum of the Philippines | Mijares A.S.,University of the Philippines at Diliman
Human Biology | Year: 2013

"Pygmy populations" are recognized in several places over the world, especially in Western Africa and in Southeast Asia (Philippine "negritos," for instance). Broadly defined as "small-bodied Homo sapiens" (compared with neighboring populations), their origins and the nature of the processes involved in the maintenance of their phenotype over time are highly debated. Major results have been recently obtained from population genetics on present-day negrito populations, but their evolutionary history remains largely unresolved. We present and discuss the Upper Pleistocene human remains recovered from Tabon Cave and Callao Cave in the Philippines, which are potentially highly relevant to these research questions. Human fossils have been recovered in large numbers from Tabon Cave (Palawan Island) but mainly from reworked and mixed sediments from several archaeological layers. We review and synthesize the long and meticulous collaborative work done on the archives left from the 1960s excavations and on the field. The results demonstrate the long history of human occupations in the cave, since at least ~30,000 BP. The examination of the Tabon human remains shows a large variability: large and robust for one part of the sample, and small and gracile for the other part. The latter would fit quite comfortably within the range of variation of Philippine negritos. Farther north, on Luzon Island, the human third metatarsal recently recovered from Callao Cave and dated to ~66,000 BP is now the oldest direct evidence of human presence in the Philippines. Previous data show that, compared with H. sapiens (including Philippine negritos), this bone presents a very small size and several unusual morphological characteristics. We present a new analytical approach using three-dimensional geometric morphometrics for comparing the Callao fossil to a wide array of extant Asian mammals, including nonhuman primates and H. sapiens. The results demonstrate that the shape of the Callao metatarsal is definitely closer to humans than to any other groups. The fossil clearly belongs to the genus Homo; however, it remains at the margin of the variation range of H. sapiens. Because of its great antiquity and the presence of another diminutive species of the genus Homo in the Wallace area during this time period (H. floresiensis), we discuss here in detail the affinities and potential relatedness of the Callao fossil with negritos that are found today on Luzon Island. © 2013 Wayne State University Press.

Mijares A.S.,University of the Philippines | Detroit F.,French Natural History Museum | Piper P.,University of the Philippines | Grun R.,Australian National University | And 6 more authors.
Journal of Human Evolution | Year: 2010

Documentation of early human migrations through Island Southeast Asia and Wallacea en route to Australia has always been problematic due to a lack of well-dated human skeletal remains. The best known modern humans are from Niah Cave in Borneo (40-42. ka), and from Tabon Cave on the island of Palawan, southwest Philippines (47±11 ka). The discovery of Homo floresiensis on the island of Flores in eastern Indonesia has also highlighted the possibilities of identifying new hominin species on islands in the region. Here, we report the discovery of a human third metatarsal from Callao Cave in northern Luzon. Direct dating of the specimen using U-series ablation has provided a minimum age estimate of 66.7 ± 1 ka, making it the oldest known human fossil in the Philippines. Its morphological features, as well as size and shape characteristics, indicate that the Callao metatarsal definitely belongs to the genus Homo. Morphometric analysis of the Callao metatarsal indicates that it has a gracile structure, close to that observed in other small-bodied Homo sapiens. Interestingly, the Callao metatarsal also falls within the morphological and size ranges of Homo habilis and H. floresiensis. Identifying whether the metatarsal represents the earliest record of H. sapiens so far recorded anywhere east of Wallace's Line requires further archaeological research, but its presence on the isolated island of Luzon over 65,000 years ago further demonstrates the abilities of humans to make open ocean crossings in the Late Pleistocene. © 2010 Elsevier Ltd.

Linkem C.W.,University of Kansas | Diesmos A.C.,National Museum of the Philippines | Brown R.M.,University of Kansas
Zoological Journal of the Linnean Society | Year: 2011

Skinks of the genus Sphenomorphus are the most diverse clade of squamates in the Philippine Archipelago. Morphological examination of these species has defined six phenotypic groups that are commonly used in characterizations of taxonomic hypotheses. We used a molecular phylogeny based on four mitochondrial and two nuclear genes to assess the group's biogeographical history in the archipelago and examine the phylogenetic validity of the currently recognized Philippine species groups. We re-examined traditional characters used to define species groups and used multivariate statistics to quantitatively evaluate group structure in morphometric space. Clustering analyses of phenotypic similarity indicate that some (but not all) members of previously defined species groups are phenotypically most similar to other members of the same group. However, when species group membership was mapped on our partitioned Bayesian phylogenetic hypothesis, only one species group corresponds to a clade; all other species group arrangements are strongly rejected by our phylogeny. Our results demonstrate that (1) previously recognized species group relationships were misled by phenotypic convergence; (2) Sphenomorphus is widely paraphyletic; and (3) multiple lineages have independently invaded the Philippines. Based on this new perspective on the phylogenetic relationships of Philippine Sphenomorphus, we revise the archipelago's diverse assemblage of species at the generic level, and resurrect and/or expand four previously recognized genera, and describe two new genera to accommodate the diversity of Philippine skinks of the Sphenomorphus group. © 2011 The Linnean Society of London.

Brown R.M.,University of Kansas | Diesmos A.C.,National Museum of the Philippines | Oliveros C.H.,University of Kansas
Journal of Herpetology | Year: 2011

We describe a new species of Luperosaurus from the Luzon faunal region, northern Philippines. The new species is most similar to, and has long been confused with, Luperosaurus cumingii from Luzon Island but differs from this and all other Luperosaurus by numerous characters of scalation, color pattern, and a suite of variables related to its small body size. The new species has been recorded at four localities along the eastern seaboard of Luzon and on Camiguin Norte, a small island just northeast of Luzon; it may also occur on Polillo and Lubang Islands. Data from our recent survey work suggest that some Luperosaurus species may be adapted to low elevation, coastal forest and that these species may now be encountered rarely now because this habitat type is so severely imperiled by centuries of deforestation and near complete development of virtually all Philippine coastlines. © 2011 Society for the Study of Amphibians and Reptiles.

Welton L.J.,University of Kansas | Siler C.D.,University of Kansas | Diesmos A.C.,National Museum of the Philippines | Brown R.M.,University of Kansas
Zootaxa | Year: 2010

Using a combination of fixed morphological character differences, mitochondrial DNA sequence data, and an estimate of phylogeny as our guide, we describe a new species of bent-toed gekkonid lizard (Genus: Cyrtodactylus) from southwestern Mindanao Island, and northeastern portions of the Sulu Archipelago, southern Philippines. The new species resembles C. annulatus, but differs from this and all other congeners by characteristics of external morphology, color pattern, and body size. In addition, the new species is distinguished from congeners by marked genetic divergence and reciprocal monophyly of mitochondrial DNA sequences. The new species is common in pristine, low elevation gallery forests throughout Pasonanca Natural Park, Zamboanga Peninsula, southwestern Mindanao Island, and the northeastern portions of the Sulu Archipelago. Copyright © 2010 Magnolia Press.

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