Luzon Island Research Articles

Structure and Variability of the Kuroshio and Luzon Undercurrent Observed by a Mooring Array

AbstractThe spatial structure and variability of the western boundary currents east of Luzon Island at 18°N are investigated using measurements collected by acoustic Doppler current profilers (ADCPs) from three moorings between January 2018 and May 2020. During the observation period, the southward velocity of Luzon Undercurrent (LUC) has a maximum greater than 0.04 m at about 800 m on average and instantaneously reaches a maximum speed of about 0.47 m . Observations indicate that the LUC and Kuroshio have significant intraseasonal variability and the LUC is reversed occasionally. We find that the strong upper‐layer anticyclonic eddy plays a key role in the weakening and reversal of LUC and that the LUC is a permanent mean undercurrent. A vertical mode decomposition analysis is employed and results show that the first two baroclinic modes explain the main vertical features of the LUC and Kuroshio at its origin. No reversal of the southward undercurrent occurs in the second baroclinic mode velocity. We conclude that the LUC variability is generally a result of the second baroclinic mode but the observed reversal of the LUC is mainly caused by the first mode.

A new jewel from the crown jewel of the South – Lake Holon: Eupyrgops almae sp. nov. (Cagas, C.L.A. &Mohagan, D.P., 2023) (Coleoptera: Curculionidae: Celeuthitini) from Mt. Melibengoy, Sitio Salacafe, T’boli, South Cotabato, Mindanao, Philippines

A new species of weevil under the genus Eupyrgops (Berg, 1898) of the family Curculionidae is discovered on the Salacafe Trail going to Lake Holon, Mt. Melibengoy, T’boli, South Cotabato, Philippines. The genus Eupyrgops is poorly known in the Philippines. There are only 11 species recorded. However, these species were only recorded on Luzon Island. Thus, making this new species a new and lone record in Mindanao, would update the list to 12 species. The new species was collected in an opportunistic manner last May 16-18, 2022. The new species Eupyrgops almae sp. nov. has a resemblance with Eupyrgops mitorajii (Alessandro Bramanti, Andrea Bramanti and Rukmane Barbale, 2020) from Luzon. This single (female holotype) specimen was deposited at the zoology section of the CMU – University Museum as a repository of the vertebrate and invertebrate fauna of Mindanao.

The early lithic productions of Island Southeast Asia: Traditions or convergences?

Island Southeast Asia has been the subject of intense prehistoric investigations since the seminal work of Eugene Dubois in the late XIXth century. This has resulted in several discoveries of a very diverse type of lithic productions of oftentimes debated age. Recent and old excavations have now secured the production of stone artefacts as early as 1 million years on Flores Island, 800,000 years on Java Island, 700,000 on Luzon Island and at least 118,000 years on Sulawesi Island. Along with these findings, several surface collections which most certainly date back to the Lower Palaeolithic are known, and adds to the diversity of the lithic productions. In this paper, we report what is at stake regarding our current knowledge over the early lithic productions of Island Southeast Asia, without giving more importance to one type of artefact over another. After describing the findings from each islands taken one by one, we compare the similarities and dissimilarities between these sometimes isolated and sometimes connected geographic entities. It appears that each of these islands might have had its own evolutionary trend with its own rhythm.

Mollusks from Miocene hydrocarbon-seep deposits in the Ilocos-Central Luzon Basin, Luzon Island, Philippines

Mollusks from Miocene hydrocarbon-seep deposits in the Ilocos-Central Luzon Basin, Luzon Island, Philippines

Inspired by Harold Conklin

Harold C. Conklin (1926-2016) is without doubt one of the key figures in ethnobotany and environmental anthropology. His work is admired for, among other qualities, its precision and its level of « fine description ». In particular, his pioneering studies on shifting cultivation have changed the general perspective on this way of land use. His Ethnographic Atlas of Ifugao (1980) is still a landmark of ethnographic fieldwork, combining a wide range of methods, including sophisticated cartography. The focus of this atlas was on the culture of Ifugao farmers in their home area in the Cordillera Mountains on the island of Luzon in the Philippines. In recent decades, thousands of Ifugao farmers have left their home area and migrated eastwards to the Sierra Madre Mountains in the northeastern part of Luzon, across Cagayan Valley. They have done so for various reasons but land shortage is certainly one of them. In the foothills of the Sierra Madre, accessible arable land became available after large-scale commercial logging operations. In this article we will draw attention to the relevance of Conklin’s work before describing how the Ifugao farmers, with their extensive knowledge and experience, have been able to turn this new area into a highly productive environment, combining wet rice fields with upland agriculture. The research is based on fieldwork that was done over several years with Filipino, Dutch and other international students in the context of a long-standing cooperation project between Isabela State University in the Philippines and Leiden University (Netherlands).

Onshore convection associated with the easterly wave over the South China Sea: A case study

A heavy rainfall event associated with a low-level shear line, a mid-level easterly wave, and a marine boundary layer jet occurred from 17 to 18 July 2017 along the coastal area of South China. The shear line was found associated with a low-level disturbance on the northwestern edge of the Luzon Island, while the easterly wave exerted significant influences on its maintenance and development over the South China Sea (SCS). Using the Global Forecast System (GFS) analysis and numerical simulations, the mechanism for the disturbance development is investigated. Along with its development, the disturbance extended upwards to the mid-level easterly wave and established an eastward-tilting structure under the effect of the vertical wind shear. When it approached the coast of South China, the height of the disturbance was lowered down due to the intensified divergence above it, and a slanting updraft was formed. A quasi-closed circulation within the easterly wave helped to protect the moist air inside and was favorable for sustained convection. The westward component of the divergent flow, which was induced by the downdraft below the easterly wave, converged in the disturbance that proved to be the primary mechanism for the disturbance development, while the cold core formed in the downdraft intensified the local baroclinicity and contributed to convection development. Although the simulation reproduced the disturbance evolution, it failed to reproduce the vertically tilting structure of the disturbance. In addition, the convection intensity in the simulation was overestimated due to the wet biases in the low troposphere. Sensitivity experiments showed that the disturbance moved faster and more westwards, when it was weakened through terrain modification, which led to stronger boundary layer jet and heavier precipitation.

How Filipino Fishers Use Traditional Knowledge in Identifying Species of Juvenile Mangrove Crabs for Grow-out Culture

Mangrove crab growers in the Philippines still rely on wild-caught late instar to early juvenile mangrove crablets, as supplies from hatcheries are limited. Any batch of crablets caught from the wild is a mix of the three native species under the genus Scylla. Scylla species have different growth rates. Since grow-out culture depends heavily on species' growth, growers should be able to distinguish the species as early as the juvenile stage, which is taxonomically difficult. This study was done to consolidate low-cost traditional identification techniques for juvenile Scylla from fishers of the Philippines for future validation. Focused group discussions were done in fishing communities from Bataan, Pangasinan, and Cagayan on the island of Luzon. The study was continued through online surveys, as travel was restricted due to the Covid-19 pandemic. Results indicate that 70.58% of respondents identify the species of crabs by looking at their claws and 55.88% observe the color of the crabs. Almost half, or 41.17% of respondents, consider the width and size of the carapace. Unique methods in certain Philippine regions include observation of the behavior patterns, carapace texture, rate of weight gain, and seasonality. Validation of the traditional practices identified in this study would result in a reliable "at-a-glance" method of identifying juvenile Scylla in the Philippines, which would shorten the culture period, improve production gains, and manage local populations.

Ardisia kalimbahin (Primulaceae, Myrsinoideae), a new species from the Philippines

Ardisia kalimbahin is herein described and illustrated as a new species. It is the latest addition to the richness of Ardisia in the Philippines. It closely resembles A. romanii Elmer but is distinct in having shorter petiole, shorter elliptic leaves, racemose inflorescence, longer and sparsely puberulent pedicels, magenta corolla lobes, basifixed anthers, shorter filaments, and a beaked stigma. Based on current collection and available herbarium specimens, Ardisia kalimbahin is distributed in the islands of Palawan (Aborlan), Mindoro, and Luzon (Carranglan). Available data is not enough to assess its conservation status; hence, it is proposed as data deficient (DD).

Air quality deterioration episode associated with a typhoon over the complex topographic environment in central Taiwan

Abstract. Air pollution is typically at its lowest in Taiwan during summer. The mean concentrations of PM10, PM2.5, and daytime ozone (08:00–17:00 LST) during summer (June–August) over central Taiwan were 35–40 µg m−3, 18–22 µg m−3, and 30–42 ppb, respectively, between 2004 and 2019. Sampling analysis revealed that the contribution of organic carbon (OC) to PM2.5 could have exceeded 30 % in urban and inland mountain sites during July in 2017 and 2018. Frequent episodes of air quality deterioration occur over the western plains of Taiwan when an easterly typhoon circulation interacts with the complex topographic structure of the island. We explored an episode of air quality deterioration that was associated with a typhoon between 15 and 17 July 2018 using the Weather Research Forecasting with Chemistry (WRF-Chem) model. The results indicated that the continual formation of low-pressure systems or typhoons in the area between Taiwan and Luzon island in the Philippines provided a strong easterly ambient flow, which lasted for an extended period between 15 and 17 July. The interaction between the easterly flow and Taiwan's Central Mountain Range (CMR) resulted in stable weather conditions and weak wind speed in western Taiwan during the study period. Numerical modeling also indicated that a lee side vortex easily formed, and the wind direction could have changed from southwesterly to northwesterly over central Taiwan because of the interaction between the typhoon circulation and the CMR. The northwesterly wind coupled with a sea breeze was conducive to the transport of air pollutants from the coastal upstream industrial and urban areas to the inland area. The dynamic process for the wind direction changed given a reasonable explanation for why the observed SO42- became the major contributor to PM2.5 during the episode. SO42- contribution proportions (%) to PM2.5 at the coastal, urban, and mountain sites were 9.4 µg m−3 (30.5 %), 12.1 µg m−3 (29.9 %), and 11.6 µg m−3 (29.7 %), respectively. Moreover, the variation of the boundary layer height had a strong effect on the concentration level of both PM2.5 and ozone. The lee vortex and land–sea breeze, as well as the boundary layer development, were the key mechanisms in air pollutant accumulation and transport. As typhoons frequently occur around Taiwan during summer and fall, their effect on the island's air quality merits further research attention.

Multivariate Characterization of Phenotypic Variation from throughout the Geographic Ranges of Philippine False Coral Snakes: Two Species or Four?

The Philippine-endemic elapid genus Hemibungarus consists of three described species that are widely distributed across northern and central portions of the archipelago. Hemibungarus calligaster, H. mcclungi, and H. gemianulis were originally diagnosed, and remain recognized today, primarily based on differences in color pattern. Previous studies and faunal checklists suggest that these species occupy distinct geographic distributions within the Philippines. However, the relatively low numbers of specimens in collections and the misidentification of older specimens under outdated taxonomy have hampered a synthetic understanding of their actual distributional limits. Thus, an in-depth revisiting of the range of external morphological and color pattern variation within and among each species is still needed to clarify species boundaries and determine whether distributional limits change once properly documented. We provide a geographic assessment of morphological variation, using 98 specimens of Hemibungarus from institutional collections and public databases to reevaluate the range of phenotypic variation exhibited by each taxon and critically assess the geographic ranges of all three species of Hemibungarus. We use these data and multivariate statistics (principal coordinate and linear discriminant analyses) to demonstrate quantitatively how meristic data support the phenotypic distinctiveness of each species and to update the identifications of all accessible specimens. Georeferencing all specimens reidentified with morphological data indicates that H. calligaster is limited to central and northern regions of Luzon Island, whereas H. gemianulis is restricted to islands in central Philippines (Visayas). Hemibungarus mcclungi, previously considered restricted to the Bicol Peninsula in southern Luzon, appears to be more widely distributed—extending north into central and northern Luzon. We also identify a population of Hemibungarus that is intermediate in morphology between the parapatric H. calligaster and H. mcclungi, which raises the question of species boundaries and should be the focus of future study. Overall, our results provide a much-needed reconsideration of the identities of all available specimens in the world's biodiversity repositories, which use newly summarized data to elucidate the geographic distributions of the members of this enigmatic elapid genus, identify future directions for research on this group, and highlight the importance of returning to verified species occurrence data from the source (museum specimens) when considering biogeographical questions, species boundaries, and all related natural history studies.

Optimization of submerged culture conditions for mycelial biomass production of fourteen Lentinus isolates from Luzon Island, Philippines

This paper is the first report on the mycelial biomass production of 14 Lentinus native isolates from Luzon Island, Philippines by submerged fermentation using the one-factor-at-time optimization technique. Coconut water (CW) was the most suitable liquid culture medium for the maximum mycelial biomass production of all studied Lentinus . The optimum initial pH of CW for most of the isolates tested was found at pH 4.0 to 7.0. In terms of physical parameters, all Lentinus isolates preferred 30 °C as the optimum temperature, indicating that they are tropical mushroom species. Lighted condition was found to be more favorable than dark condition for most Lentinus isolates tested. Some isolates preferred static-flask culture condition, while some isolates showed comparable yields in both culture conditions. The mycelial biomass production of 14 Lentinus isolates was significantly increased by 1.2–1.7-fold when grown in the optimized submerged culture condition. Among Lentinus isolates, L. swartzii BIL4618 consistently recorded the highest biomass yield in all optimization parameters. Therefore, the mycelial biomass productivity of 14 Lentinus may vary depending on the species and isolates and this can be enhanced by growing them in their optimized submerged culture conditions. The chemical constituents and biological activities of extracts of mass-produced mycelia are currently under investigation. • Coconut water (CW) at pH 4–7 is the most suitable culture medium for fourteen Lentinus isolates from the Philippines. • Physical factors affect the mycelial biomass production of Lentinus isolates. • Mycelial biomass production increased by 1.2–1.7-fold when grown in the optimized submerged culture condition. • Lentinus swartzii BIL4618 isolate produced the highest biomass yield in all optimization parameters.

ELUCIDATING THE GONADAL DEVELOPMENT AND SEX DIFFERENTIATION OF THE RICE PADDY EEL, Monopterus albus (Zuiew, 1993), BASED ON GONADAL HISTOMORPHOLOGY AND STEROID HORMONE LEVELS

The establishment and survival of the population of species in their breeding ground can be attributed to the species’ reproductive characteristic and capacity. The Monopterus albus species is an introduced fish in the Philippines. It is a protogynous hermaphrodite which has a natural ability for sex reversal. This study describes the histomorphology of the different stages of gonadal maturation and determines the concentration levels of the steroid hormones 17ß-estradiol (E2) and testosterone (T) in the blood plasma. These aim to a further understanding on the gonadal development and sex differentiation of the rice paddy eel as a hermaphroditic fish. Fish samples were collected randomly from farm ponds located in three provinces within the island of Luzon, Philippines. The sexual identity of the fish was categorized based on the presence or absence of ovarian and testicular tissues. Histological analysis of the gonad showed that immature, maturing-matured female gonad exhibited ovarian tissues of varying stages. The intersex gonad showed the existence of both ovarian and testicular tissues. Enzyme-linked immunosorbent assay (ELISA) was used to determine the concentration levels of gonadal steroid hormones. Differences in the concentration levels of the two hormones were evident across all the stages of gonad maturation. The functional role of these hormones in vitellogenesis and spermatogenesis leads to the development of this sex-changing gonads. This reproductive characteristic contributes to our understanding of the reproductive success of hermaphroditic fish.

THE ROLE OF SELECTED HIGHER EDUCATIONAL INSTITUTIONS (HEIS) AND LOCAL GOVERNMENT UNITS ON INTEGRATING FOOD HERITAGE RESEARCH INTO POLITICAL PRIORITIES: A PUBLIC POLICY ANALYSIS OF LUZON ISLAND, PHILIPPINES

The purpose of this study is to show how food heritage, specifically Filipino Pancit, define the culture oftheir citizens, investigate the efforts of Local Government Units (LGUs), and examine the role of a selectedHigher Educational Institution (HEI) as a partner of LGUs in safeguarding food heritage. The researcher
 used frameworks from international and national cultural agencies and researchers. Observation and in-depth interviews were also used for the documentation process through case study technique, which
 examined the aspects of statutory control and safeguarding mechanisms to determine the political prioritiesof involved LGUs and the selected HEI’s role in safeguarding food heritage in the islands of Luzon,Philippines. Findings suggest that LGUs’ sheer political will, knowledge, and awareness on issues onheritage conservation, openness, sustainable practices, and multi-stakeholder participation are essential inrobust protection vis-à-vis culture and heritage conservation. This comes with the active participation ofstakeholders, especially academic institutions, which provide expertise and extra leg work on researchbacked by their advocacy rooted on Filipino identity and sustainability to support policies of the government.Ultimately, research-based policymaking is key to open opportunities not just on intangible cultural heritagelike Filipino Pancit but on culture and heritage conservation in general.

Review of potential astronomical optical observatory sites in the Philippines

The Philippines is an archipelago of more than 7,600 islands with many geographical features such as mountain ranges, seas, and plains. The country has fairly developed cities that are now experiencing various kinds of pollution at different levels and intensities. Highly developed urban areas are brightly lit and are currently experiencing worsening light pollution. Despite this, the two biggest telescopes in the country are still installed in two observatories right in the country’s capital city where light pollution is at its worst. This paper aims to identify several locations away from light pollution in the islands of Luzon, the biggest island in the Philippines, and the island of Palawan, where optical astronomical observatories may be built. The locations are chosen by studying the comparative light pollution scales in the various locations. The topography of the place and meteorological data such as temperature, humidity, and precipitation are likewise studied and considered as factors. Included in these factors is the fact that both the islands of Luzon and Palawan experience several typhoons every year, while earthquakes occur anywhere in the archipelago. For this reason, the observatories to be built must be designed to withstand Category 5 typhoons and strong magnitude 7 to 8 earthquakes. The results of the study identify the places on the island of Palawan and in northern Luzon which are good dark sites for the establishment of optical astronomy observatories. These locations can be declared as protected and developed as dark-sky sites dedicated to the study of Astronomy.

The Conventional and Modern Uses of Water Buffalo Milk in the Philippines

In Southeast Asia, milking of livestock is not common. In the Philippines, water buffalo (carabao) milk has been used since the Spanish colonial period of the 16th century. Milk is processed into cheese (kesong puti) or candy (pastillas). These customs are found in a few areas on the Islands of Luzon and Visayas. However, in 1996, following the launch of the Philippine Carabao Center (PCC), the uses of modern milk have been practiced nationwide using Murrah (buffalo), which produces more milk than a carabao. This paper analyzes the dairy transition currently occurring in the Philippines from the conventional uses of carabao milk to the modern uses of Murrah milk. Intensive fieldwork was broadly conducted in conventional and modern milk use areas of the country, with water buffalo management and milk use systems researched using participatory observation and interview methods. This study delves into how the conventional uses of water buffalo milk have helped support the livelihood of special farmers and whether recent government-backed projects, such as enhancing the ability of water buffaloes to produce milk, have made carabaos dispensable. The shift to modern milk uses, which relies on buffalo milk, has become a national project, in order to improve the subsistence of peasant farmers. This paper concludes that the modern dairy farming of Murrah is becoming popular in farming societies close to the PCC and that the dairy culture has changed from being a minor conventional regional system to a major industrial farming and business system to sustain the lives of local small-scale farmers.

Taxonomic Revision of Scaly-toed Geckos (Reptilia: Gekkonidae: Lepidodactylus) in the Northern Philippines, with Descriptions of Four New Species

Recent higher level phylogenetic analyses of gekkonid lizards of the genus Lepidodactylus uncovered an array of unrecognized species diversity, particularly within the Philippine archipelago. Novel phylogenetic analyses of multilocus data sets suggest that as many as five, previously undescribed, species-level lineages of Scaly-toed Geckos occur in just the northern portions of the archipelago. Here, we evaluate Lepidodactylus species diversity in the Lepidodactylus yami–balioburius clade and describe four new forest species from Luzon Island and surrounding minor island groups. Interestingly, these species are the first endemic Lepidodactylus taxa described from Luzon proper and peripheral islands. In this first review of Philippine Scaly-toed Gecko diversity in nearly half a century, we use a suite of morphological characters along with molecular data to delimit evolutionary lineages. All species described in this paper can be distinguished from congeners by an array of discrete external traits; all are also monophyletic groups, separated in our phylogenetic analyses of the mitochondrial ND2 gene. This study increases significantly the number of known Scaly-toed Geckos in the Philippines from 7 to 11, which is likely still an underestimate of the species diversity in this understudied clade.

Genetic Diversity and Population Structure of Sugarcane (Saccharum officinarum L.) Collected from Seven Philippine Regions for Use as Breeding Stocks for Crop Improvement

Selection of parents for hybridization relies on the information on their genetic relationship and diversity which are essential in any breeding program. This study aimed to estimate the extent of genetic diversity and population structure of 76 sugarcane accessions from seven regions in the Philippines using 57 morphological characters and 50 microsatellite markers. The sugarcane collections exhibited moderate to high diversity with mean of H’ = 0.72 for qualitative and H’ = 0.75 for quantitative morphological characters, respectively. This is corroborated by the analysis of variance (ANOVA) of agronomic parameters, except for stalk length. Unweighted Pair Group Method with Arithmetic Mean (UPGMA) cluster analysis based on morphology subdivided the accessions into 31 clusters which reveal phenotypic variability among sugarcane samples. The fingerprints of the 76 accessions were also evaluated using 45 Saccharum-based genomic SSR and 5 EST-SSR primer pairs to measure genetic diversity and population structure. Based on UPGMA, a total of six clusters were generated with a 0.65 coefficient of dissimilarity, and the sugarcane accessions were further subdivided into five major sub-populations. Out of 50 markers used, 41 (82%) were found to be highly informative with a mean PIC value of 0.69. It was also expected that Saccharum-based genomic SSRs were more polymorphic (92%) compared to EST-SSRs (82%) since the latter preferably amplify in more conserved and expressed sequences in the genome. Out of 2,850 pairwise combinations based on the Jaccard coefficient index, large diverse parental combinations (genetic dissimilarity= 0.51 -0.70) were observed, indicating substantial diversity from the existing breeding pool of IPB-UPLB for genetic improvement. Cluster analysis based on UPGMA, STRUCTURE analysis, and Principal Coordinate Analysis (PCoA) were predominantly consistent. However, no association was observed between the geographical origin and genetic distance of the genotypes based on molecular data. The results showed that accessions were grouped into five sub-populations and genetic differentiation within sub-population was higher (85%) as compared to between sub-population (15%) based on the analysis of molecular variance (AMOVA), suggesting an active exchange of genetic pool across provinces and regions of both Luzon and Visayas islands. The findings from this study will be useful for future breeding efforts by exploiting genetic variation existing in the current breeding population.

King or royal family? Testing for species boundaries in the King Cobra, Ophiophagus hannah (Cantor, 1836), using morphology and multilocus DNA analyses

In widespread species, the diverse ecological conditions in which the populations occur, and the presence of many potential geographical barriers through their range are expected to have created ample opportunities for the evolution of distinct, often cryptic lineages. In this work, we tested for species boundaries in one such widespread species, the king cobra, Ophiophagus hannah (Cantor, 1836), a largely tropical elapid snake distributed across the Oriental realm. Based on extensive geographical sampling across most of the range of the species, we initially tested for candidate species (CS) using Maximum-Likelihood analysis of mitochondrial genes. We then tested the resulting CS using both morphological data and sequences of three single-copy nuclear genes. We used snapclust to determine the optimal number of clusters in the nuclear dataset, and Bayesian Phylogenetics and Phylogeography (BPP) to test for likely species status. We used non-metric multidimensional scaling (nMDS) analysis for discerning morphological separation. We recovered four independently evolving, geographically separated lineages that we consider Confirmed Candidate Species: (1) Western Ghats lineage; (2) Indo-Chinese lineage (3) Indo-Malayan lineage; (4) Luzon Island lineage, in the Philippine Archipelago. We discuss patterns of lineage divergence, particularly in the context of low morphological divergence, and the conservation implications of recognizing several endemic king cobra lineages.

Isles of Passages: Transport geography perspective on Calayan and Lubang as gateways to the main Island of Luzon (Metal ages to early historical period, 500 BCE to CE 1600)

Archaeological works have tended to privilege the processes behind the rise and fall of ancient culture- centers (as defined by Wallerstein 2004 in World Systems Theory) while some have attempted to integrate more data on the changes that take place in strategic nodes or peripheries that ‘feed’ into these centers (Junker and Smith, 2017; Hendrickson et al., 2013). This paper tackles how social-historical transformations may have become an impetus in the waxing and waning of gateway/ gatekeeper locations using transport geography perspective. At the center of the case study are two strategic island nodes connecting to the main Island of Luzon- – Calayan and Lubang group. The paper attempts to demonstrate that due to social-historical factors specifically evolving trade, colonial assimilation, and technological diffusion, these key players have eventually taken a backseat in the transportation and communication network in this crucial passage to Island Southeast Asia. The crux of the argument lies on probative evidence that these islands possibly supported more inhabitants before the Spanish Contact period in the 16th c, using boat shaped burial complexes and ijang (garrison) complexes as proxy indicators. Aided by geomatics and remote sensing and geographic information systems (RS-GIS) algorithms including maximum likelihood classification, band maths as well as principal component analysis, the paper emphasizes the density of possible archaeological sites in both island locales as the proxy indicator to the pre-Contact period populations. The paper argues that the introduction of blue water maritime vessels with the opening of the Manila-Acapulco galleon trade (Wu, 2019; Dizon, 2004; Dizon, 2003; Schurz, 1985 on the Manila Galleon) contributed to the waning of the strategic importance of these island nodes with the final straw being the Spanish colonial administrations’ policy of depopulating these smaller islands and relocating them to their colonial- panoptic landscapes in Luzon. The role of the prevailing market situation as dictated by rapidly evolving scales of transactions from evanescent to more permanent markets (Canilao, 2020) may have also contributed to the emergent new status quo in these isles of passage.

Amorphophallus minimus (Araceae), a new species from the montane forest of Nueva Ecija, Luzon island, Philippines

Amorphophallus minimus (Araceae) is herein described and illustrated as a new species from the montane forest of Nueva Ecija, Luzon island, Philippines. A. minimus has an overall resemblance to Amorphophallus palawanensis Bogner and Hett., however, it is easily distinguished by having a club‐shaped and colliculate appendix that is contiguous with the male zone, oblate stamens (2 per flower), presence of leaf bulbils, and its overall small dimensions. Amorphophallus minimus is currently the only species in the Philippines found to inhabit a montane forest ecosystem.