Southeastern Luzon Research Articles

Tidally Forced Turbulent Dissipation on a Three-Dimensional Fan in Luzon Strait

Abstract Moored observations and a realistic, tidally forced 3D model are presented of flow and internal-tide-driven turbulence over a supercritical 3D fan in southeastern Luzon Strait. Two stacked moored profilers, an acoustic Doppler current profiler, and a thermistor string measured horizontal velocity, density, and salinity over nearly the entire water column every 1.5 h for 50 days. Observed dissipation rate computed from Thorpe scales decays away from the bottom and shows a strong spring–neap cycle; observed depth-integrated dissipation rate scales as where UBT is the barotropic velocity. Vertical velocities are strong enough to be comparable at times to the vertical profiling speed of the moored profilers, requiring careful treatment to quantify bias in dissipation rate estimates. Observations and the model are in reasonable agreement for velocity, internal wave displacement and depth-integrated dissipation rate, allowing the model to be used to understand the 3D flow. Turbulence is maximum following the transition from up-fan to down-fan flow, consistent with breaking lee waves advected past the mooring as seen previously at the Hawaiian Ridge, but asymmetric flow arises because of the 3D topography. Observed turbulence varies by a factor of 2 over the four observed spring tides as low-frequency near-bottom flow changes, but the exact means for inclusion of such low-frequency effects is not clear. Our results suggest that for the extremely energetic turbulence associated with breaking lee waves, dissipation rates may be quantitatively predicted to within a factor of 2 or so using numerical models and simple scalings. Significance Statement This paper describes deep ocean turbulence caused by strong tidal and low-frequency meandering flows over and around a three-dimensional bump, using moored observations and a computer simulation. Such information is important for accurately including these effects in climate simulations. The observations and model agree well enough to be able to use both to synthesize a coherent picture. The observed and modeled turbulence scale as the cube of the tidal speed as expected from theory, but low-frequency flows complicate the picture. We also demonstrate the underestimation of the turbulence that can result when vertical profiling rates are comparable to the internal wave velocities.

First record of blacknape large-eye bream Gymnocranius satoi (Perciformes: Lethrinidae) in the Philippines

The Philippines has been regarded as the center of the center of marine shorefish biodiversity, having the highest number of fish species per square area in the world. The blacknape large-eye bream, Gymnocranius satoi, has been reported to occur from Southern Japan, Taiwan to Northwestern Australia and to the Coral Sea, but has not previously been recorded from the Philippines. From 2011 – 2019, the National Fisheries Research and Development Institute (NFRDI) collaborated with the National Museum of Natural History of the Smithsonian Institution (NMNH/SI), USA, and the Old Dominion University (ODU), Virgina, USA, to inventory all commercial fish species sold in fish markets around the Philippines. During three (3) fish market surveys (Dumaguete City Market, Negros Oriental; Claveria Public Market, Cagayan, Northern Luzon; and Tabaco City Market, Albay, Southeastern Luzon in 2013, 2016 and 2017, respectively), we collected and eventually identified using morphological and DNA barcoding (COI) analysis, seven (7) specimens of G. satoi, representing the first records of this species from the country. Since the potential to discover new species and first records of fish species in the Philippines is high, further taxonomic study of the genus Gymnocranius is needed.

Adakitic Paracale Granodiorite in southeastern Luzon, Philippines: A peek at a Proto-Philippine Sea Plate-related magmatic arc

This paper describes the geochemistry, petrogenesis and tectonic setting of a silicic pluton, the Paracale Granodiorite (PG), intruded into an ophiolitic suite in southeastern Luzon island, Philippines. Whole rock chemistry suggests that the PG samples are calc-alkaline and are characterized by light rare earth element (LREE)-enrichment and relatively weak heavy rare earth element (HREE)-depletion. They also show depletion in Nb, Ta, Zr and Ti and positive anomalies in K, Pb and Sr when normalized with the Primordial Mantle and normal-mid-ocean ridge basalt (N-MORB). The PG biotite mineral chemistry shows an affinity to calc-alkaline trends based on the FeOtot versus Al2O3, whereas in the MgO-Al2O3 plot, they exhibit transitional calc-alkaline to peraluminous characteristics. These information, along with a temperature >600 °C based on biotite chemistry, and hydrous setting for the generation of the PG suggest generation in a subduction-related setting. When plotted in the Y versus Sr/Y and YbN versus (La/Yb)N, the PG samples exhibit adakitic signature. Partial melting, fluid addition and sediment participation are discerned from the geochemistry. Melting, assimilation, storage and homogenization (MASH) with limited fractionation are the dominant mechanisms of formation. The PG could represent a Late Cretaceous to Paleogene magmatic arc generated during the subduction of the proto-Philippine Sea Plate.

Prevalence, diversity and co-occurrence of the white spot syndrome virus, monodon baculovirus and Penaeus stylirostris densovirus in wild populations of Penaeus monodon in the Philippines

The farming of the black tiger shrimp Penaeus monodon in the Philippines relies on wild broodstock. PCR was thus used to determine the prevalence of white spot syndrome virus (WSSV), monodon baculovirus (MBV) and Penaeus stylirostris densovirus (PstDV) in a total of 178 shrimp from 6 geographically disparate locations where broodstock are captured for use in hatcheries. PCR amplicons were also sequenced to identify phylogenetic relationships of the virus haplotypes detected. Shrimp from southeastern Luzon (Camarines Norte) had the highest prevalence of each of the 3 viruses and were frequently co-infected with 2 or more viruses. No viruses were detected in shrimp from northwestern Luzon (Pangasinan). MBV was most prevalent and PstDV strains displayed the most genetic diversity. WSSV was detected at 3 sites, and a VP28 gene sequence examined was invariant and consistent with strains found in many countries, including Thailand, China, Japan, Korea, Indonesia, Iran, Brazil and Mexico. WSSV open reading frame 94 gene sequence analysis identified location-specific repeat types. MBV sequences were dissimilar to haplotypes detected in India. PstDV sequences were diverse and included 2 lineages detected either in Australia or in the United States, Ecuador, Taiwan, China and Vietnam. The PCR data confirmed that WSSV, MBV and PstDV are endemic in P. monodon in the Philippines but that populations at some locations might remain free of infection.

Rafflesia camarinensis (Rafflesiaceae), A New Species from Mt. Asog, Camarines Sur, Luzon Island, Philippines

Rafflesia camarinensis, a new species of Rafflesia, is described from Mt. Asog, Camarines Sur in southeastern Luzon, Philippines. The species is remarkable in being one of the smallest Rafflesia in the Philippines with flower diameter measuring just 11-13 cm across. It is distinguished from R. baletei from the adjoining Mt. Isarog by various characters more notably its smaller size, dome-shaped perigone lobes, thicker and almost woody texture, less dense warts which are more or less homogeneous and raised, fewer, shorter and randomly distributed processes, and a diaphragm concolorous with the perigone lobes and with continuous thick white warts on its surface. It has a very narrow distribution, is critically endangered and needs immediate conservation actions.

Summer Convective Afternoon Rainfall Simulation and Projection Using WRF Driven by Global Climate Model. Part II: Over South China and Luzon

This study is the second of a two-part investigation into summer convective afternoon rainfall (CAR) simulation and projection over the East Asian continents. In Part I, we examined the CAR activity over Taiwan. In this study we focus on CAR activity over South China and Luzon using the WRF (Weather Research and Forecasting Model) driven by HiRAM (High Resolution Atmospheric Model) (i.e., WRF-HiRAM). These examinations focus on two time-sliced simulations assuming the climate conditions at present (1979 - 2003, historical run) and at the end of the 21^(st) century (2075 - 2099, RCP 8.5 scenario). The results show that WRF-HiRAM is capable of simulating the spatial-temporal variation in CAR activity over South China and Luzon close to the recorded observations. In the future projections, WRF-HiRAM predicts that CAR events over most of South China and eastern Luzon will become fewer but stronger. Conversely, CAR events over western Luzon will become more frequent and stronger. Analyses also indicate that the projected change in CAR amount over most of South China (except for the coastal regions) and Luzon will be dominated by the change in CAR rate, not the change in CAR frequency. As for the cause of change in CAR rate, WRF-HiRAM projects that atmospheric humidity over South China and Luzon will increase significantly in the future. This will lead to an increase in local CAR rate. In contrast, the projected change in CAR frequency over South China and Luzon is suggested to be greatly modulated by the change in daytime surface wind convergence and thermal instability. Examinations were also performed to document the characteristics and causes of the projected change in CAR activity extracted from HiRAM.

Types of reduplication: A case study of Bikol by Veronika Mattes (review)

Reviewed by: Types of reduplication: A case study of Bikol by Veronika Mattes Carl Rubino Types of reduplication: A case study of Bikol. By Veronika Mattes. Berlin: De Gruyter Mouton, 2014. Pp. 222. ISBN 9783110362978. $168 (Hb). Veronika Mattes’s volume is a revised and expanded version of her dissertation submitted to the University of Graz in 2007. It is a culmination of an extensive literature review of multiple Philippine languages and two fieldwork trips to the Bikol Peninsula, supported by two reduplication projects at the University of Graz and the University of Bremen. The Bikol Peninsula of Southeastern Luzon Island, Philippines, is home to a variety of Austronesian dialects collectively referred to as ‘Bikol(ano)’. All dialects of this language, as well as sister Philippine languages, are particularly rich in both inflectional and derivational reduplication. The analysis in this book mostly stems from the Legazpi dialect in which recordings of spontaneous speech and elicitation sessions were collected. In addition to the corpus M generated, she extracted all reduplicated forms attested in Mintz and Del Rosário Britanico’s (1985) dictionary and verified every entry with at least two speakers. The book is divided into six chapters and an appendix. Ch. 1 sets the stage for M’s interest in the topic and outlines the format of the book. Ch. 2 provides a grammar sketch of the Bikol language aimed at helping the reader maneuver through the copious examples throughout the book. In Ch. 3, M discusses reduplication in general, defining the topic with respect to the scope of her analysis. In Chs. 4 and 5, M presents the results of her study, productive reduplication in Ch. 4 and lexicalized reduplication in Ch. 5. In Ch. 6, she provides a synopsis of the major issues, then details the corpora and fieldwork annotations in the appendix. Of particular value to this volume is her excellent treatment of Bikol phonology and morphosyntax. This includes an introduction to the Bikol phoneme inventory and morphophonemic processes the readers must understand to navigate the examples. These include nasal assimilation, stress, h-epenthesis, and the status of the phonemes /r/ and /l/. Her examples are written in a current orthography that has not been universally standardized. In her treatment of the Bikol lexicon, M introduces the concept of an open class of categorically indistinct content words, mostly disyllabic in nature, from which both nouns and verbs can be derived via morphological processes, and a closed class of function words. Following Naylor (2006) and Himmelmann (2007), M justifies considering bare roots in Bikol to be ontological nominals that must derive verbal meanings by affixation of tense/aspect/modality (TAM) markers or voice morphology. Her analysis of Bikol grammatical relations is largely adopted from Himmelmann 1987, where the syntactically privileged argument with respect to the predicate is called the ‘predicate base’, referred to by various terms by other linguists, including subject/nominative argument, pivot, absolutive argument, focus, and trigger. The term ‘predicate base’ has not stuck for Philippine languages. Even Himmelmann (2007) has reverted to using the term ‘subject’, although other terms may more adequately cover this concept without discourse or syntactic implications, for example, Lehmann’s (1984:355) Ausrichtungsmarkieurung ‘orientation/alignment marking’ and Rubino’s (2006) ‘orientation’. Bikol is categorized as an agglutinating language with some inflectional features like syncretism and fusion. It is a predicate-initial language with no copula, no agreement marking, and no grammatical gender. M succinctly and accurately summarizes Bikol syntax as having an ‘alternating sequence of content and function words. Each argument is preceded by a phrase marker and each marker is connected with its head by a linker’ (17–18). Inflectional reduplication is immediately apparent in the paradigms M illustrates in her discussion of voice and TAM morphology. An interesting part of her study for Philippine specialists concerns the omission of TAM and voice morphology ‘when the speaker and addressee share enough background knowledge’ (22–23). This insight offers a refreshing perspective rarely seen from grammarians and typologists who do not feed their analyses from spontaneous spoken discourse data. The grammatical analysis closes with a word on derivational affixes and a section on nonobligatory number marking. M discusses three...

A new species of limestone karst inhabiting forest frog, genus Platymantis (Amphibia: Anura: Ceratobatrachidae: subgenus Lupacolus) from southern Luzon Island, Philippines.

We describe a new species of limestone karst dwelling forest frog of the genus Platymantis from the Quezon Protected Landscape in southeastern Luzon Island, Philippines. We assign Platymantis quezoni, sp. nov., to the diverse assemblage of terrestrial species in the Platymantis dorsalis Group, subgenus Lupacolus on the basis of its body size and proportions, only slightly expanded terminal discs of the fingers and toes, and its terrestrial microhabitat. The new species is distinguished from these and all other Philippine congeners by features of its external morphology, its restriction to a distinctive limestone karst microhabitat, and its advertisement call, which is unique among frogs of the family Ceratobatrachidae. Several distinguishing morphological characters include its moderate body size (22.1-33.9 mm SVL for 16 adult males and 32.4-39.7 mm SVL for five adult females), slightly expanded terminal discs of the fingers and toes, smooth skin with limited dermal tuberculation, and a dorsal color pattern of mottled tan to dark brown with black blotches. The new species is the sixth Philippine Platymantis known to occur exclusively on limestone karst substrates (previously known karst-obligate species include: P. bayani, P. biak, P. insulatus, P. paengi, and P. speleaus). Recently accelerated discovery of limestone karst anurans across the Philippines suggests that numerous additional species may await discovery on the hundreds of scattered karst formations throughout the archipelago. This possibility suggests that a major conservation priority in coming years will be to study, characterize, describe, and preserve the endemic species supported by this patchy, unique and imperiled type of forest ecosystem in the Philippines.

Indigenous Knowledge and Sustainable Pest Management in Rice Farming Communities of southeastern Luzon, Philippines

The paper presents the traditional pest management systems in the rice-growing areas of the southeastern part of Luzon, Philippines, particularly in the province of Camarines Sur. These systems have been proven to be productive, sustainable, ecologically sound, and attuned to the social, economic, and cultural features of the food-poor small farmers in the said province. The various indigenous pest control strategies were recorded and classified into cultural, physical, biological, mechanical, and chemical. A mixture of qualitative techniques such as interview guides and Focus Group Discussions were used in the survey. Results indicate that, despite the increasing modernization and commercialization of agriculture, the great majority of respondents who are peasants or marginal farmers still strongly embrace and patronize the use of Indigenous Knowledge (IK) that they have inherited from their ancestors many decades ago. IK on pest management have helped them control and sustainably manage pest problems and meet their subsistence needs without depending on costly energy-based inputs. IK should therefore be recorded and used to devise innovative research for agricultural researchers, extension workers, development practitioners, and environmentalists for sustainable pest management before this wealth of practical knowledge is lost forever since most of the indigenous management techniques for rice pest control are rapidly disappearing as affected by major social, economic, and political pressures.

Antitubercular constituents from Premna odorata Blanco

Ethnopharmacological relevancePremna odorata Blanco (Lamiaceae) is a medicinal plant traditionally used in Albay Province, in southeastern Luzon, Philippines to treat tuberculosis. This study aimed to determine the antitubercular property of the crude extract and sub-extracts of the leaves, and to isolate the bioactive principles from the active fractions. Materials and methodsThrough extraction, solvent polarity-based fractionation and silica gel chromatography purification of the DCM sub-extract, compound mixtures from the bioactive fractions were isolated and screened for their in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv using the colorimetric Microplate Alamar Blue assay (MABA). ResultsThe crude methanolic extract and sub-extracts showed poor inhibitory activity against Mycobacterium tuberculosis H37Rv (MIC≥128µg/mL). However, increased inhibitory potency was observed for fractions eluted from the DCM sub-extract (MIC=54 to 120µg/mL). Further purification of the most active fraction (MIC=54µg/mL) led to the isolation of a 1-heneicosyl formate (1), 4:1 mixture of β-sitosterol (2), stigmasterol (3) and diosmetin (4), which were identified through GC–MS analysis (with dereplication) and NMR experiments. The MIC of compound 1 was 8µg/mL. ConclusionsThe results of this study provide scientific basis for the traditional use of Premna odorata as treatment for tuberculosis.

A model‐based test of accuracy of seawater oxygen isotope ratio record derived from a coral dual proxy method at southeastern Luzon Island, the Philippines

The oxygen isotope ratio in seawater (δ18Osw) is an important indicator of past hydroclimatic conditions in the tropics. In this study, we apply a dual proxy approach using δ18O and Sr/Ca in coral skeletons to estimate δ18Osw. Due to a lack of long‐term continuous observational data for δ18Osw, a simplified one‐dimensional box model of the ocean surface associated with historical surface atmospheric data is used for comparison with coral‐derived δ18Osw record. The atmospheric data consist of the precipitation and evaporation values, together with their δ18O compositions from the global isotope reanalysis data. The model successfully reproduces a multidecadal time series for δ18Osw at southeastern Luzon Island, the Philippines, for the period 1979–2001 (r = 0.57, p < 0.01). The result suggests that the coral records are an accurate indicator of hydrological cycle changes at the site. A discrepancy between the reproduction and the coral record in the wet season (December–February) may be caused by seasonal variation in the depth of the mixed layer and upwelling, since these factors are not accounted for in the model. The reproduction is in good agreement with the coral records in the dry season (April–June), implying that δ18Osw estimated using the coral dual proxy method is more robust at this time of year.

Radiolarian biostratigraphic data from the Casiguran Ophiolite, Northern Sierra Madre, Luzon, Philippines: Stratigraphic and tectonic implications

Results from the first detailed radiolarian biostratigraphic study conducted in Luzon are reported. The data were obtained from cherts associated with the Casiguran Ophiolite, a dismembered ophiolite mass consisting of serpentinized peridotites, gabbros, dolerite dikes and pillow basalts exposed along the eastern coast of the Northern Sierra Madre, Luzon, Philippines. Cherts and limestone interbeds conformably overlie the ophiolite. The radiolarian assemblages from the cherts constrain the stratigraphic range of the cherts to the Lower Cretaceous (upper Barremian–lower Aptian to Albian). This new biostratigraphic result is in contrast with the Upper Cretaceous stratigraphic range previously reported in the region.Radiolarian biostratigraphic results from the Casiguran Ophiolite provide additional evidence for the existence of Mesozoic oceanic substratum upon which Luzon and neighboring regions within the Philippine archipelago were likely built. Interestingly, the result closely resembles those reported for the ophiolite in southeastern Luzon as well as the oceanic crust of the Huatung Basin situated east of Taiwan and the ophiolites in eastern Indonesia. In light of this, along with previously gathered geochemical data from the ophiolites, a common provenance is being looked into for these crust–upper mantle sequences in the western Pacific region.

Volcano-tectonic controls and emplacement kinematics of the Iriga debris avalanches (Philippines)

Mt Iriga in southeastern Luzon is known for its spectacular collapse scar that was possibly created in 1628 ad by a 1.5-km3 debris avalanche. The debris avalanche deposit (DAD) covered 70 km2 and dammed the Barit River to form Lake Buhi. The collapse has been ascribed to a non-volcanic trigger related to a major strike-slip fault under the volcano. Using a combination of fieldwork and remote sensing, we have identified a similar size, older DAD to the southwest of the edifice that originated from a sector oblique to the underlying strike-slip fault. Both deposits cover wide areas of low, waterlogged plains, to a distance of about 16 km for the oldest and 12 km for the youngest. Hundreds of metre-wide and up to 50-m-high hummocks of intact conglomerate, sand and clay units derived from the base of the volcano show that the initial failure planes cut deep into the substrata. In addition, large proportions of both DAD consist of ring-plain sediments that were incorporated by soft-sediment bulking and extensive bulldozing. An ignimbrite unit incorporated into the younger DAD forms small (less than 5 m high) discrete hummocks between the larger ones. Both debris avalanches slid over water-saturated soft sediment or ignimbrite and spread out on a basal shear zone, accommodated by horst and graben formation and strike-slip faults in the main mass. The faults are listric and flatten into a well-developed basal shear zone. This shear zone contains components from the substrate and has a diffuse contact with the intact substrata. Long, transport-normal ridges in the distal parts are evidence of compression related to deceleration and bulldozing. The collapse orientation and structure on both sectors and DAD constituents are consistent with collapse being a response to combined transtensional faulting and gravity spreading. Iriga can serve as a model for other volcanoes, such as Mayon, that stand in sedimentary basins undergoing transtensional strike-slip faulting.

Assessment of the fishery of siganid juveniles caught by bagnet in Lagonoy Gulf, Southeastern Luzon, Philippines

Summary Long-term, excessive harvesting of juvenile fish could lead to significant decline in their settlement strength. In the Philippines, the exploitation of siganid juveniles forms an important traditional fishery but no assessment of the exploitation status of such fishery had been made. The present study is a comprehensive assessment of the siganid juvenile fishery caught by bagnet in Lagonoy Gulf (Southeastern Luzon) by analyzing the temporal trend of their catch and effort statistics. Seven species of siganid juveniles composed the catch, which was dominated by Siganus canaliculatus (78%), S. spinus (8%) and S. argenteus (3%). Total catch 2001 through 2004 was 175 tonnes (t), 154 t, 130 t and 65 t, respectively. The total catch as well as the catch-per-unit-effort declined steeply in these 4 years. Juvenile occurrences or ‘runs’ were observed throughout the year except in some months in the later quarters of 2003 and 2004. Catches for all 4 years were always highest in April and May, occurring on or about the new moon mostly at the Albay East Coast. Overfishing must be stopped in order to prevent the collapse of this resource.

Bat diversity in tropical forest and agro-pastoral habitats within a protected area in the Philippines

Parks and other protected areas in tropical forests often include secondary forest, cropland, and pasture. Documentation of the impact of such anthropogenic disturbance is essential for effective management. We re-sampled bats within Mount Isarog Natural Park (MINP), a protected area in southeastern Luzon, Philippines, seventeen years after a survey in old- and second-growth forest and in agro-pastoral areas was conducted in 1988. By employing harp traps and a tunnel trap, in addition to mist nets as used in the earlier study, we aimed to document species previously undetected by mist netting alone. We documented 26 bat species, seven of which were captured exclusively in harp traps, and two that were only captured in a tunnel trap. This survey resulted in nine new records of bat species for MINP, bringing the total number to 30. We did not recapture four species documented in 1988, all of which were noted in that study as uncommon. Nineteen species were captured in agro-pastoral areas on the south slope, including two Hipposideros spp. not captured at the forested sites.

Descriptions of two New Species ofRhynchomysThomas (Rodentia: Muridae: Murinae) from Luzon Island, Philippines

Rhynchomys belongs to a unique assemblage of Philippine rodents that exhibit a combination of primitive features as well as unique morphological specializations. These nocturnal “shrew-rats,” with highly specialized vermivorous and insectivorous food habits, are endemic to Luzon Island. Analyses of external, cranial, and dental features support the recognition of 4 species, 2 of which are described in this paper. All are restricted to high-elevation habitats, about 1,100 m and above, in montane and mossy forest on northern, western, and southeastern Luzon. Habitat vicariance and subsequent divergence in isolation is the probable mode of diversification in Rhynchomys as well as in other murid clades whose members are restricted to high-elevation habitats. The discovery of locally endemic species of Rhynchomys both confirms the existence of multiple centers of endemism on Luzon and underscores the need to establish and maintain additional protected areas on the island.

Monograph of the green macroalgal genus Rhipilia (Udoteaceae, Halimedales), with a description of R. crassa sp. nov. from Australia and the Philippines

Examination of type and authentic material of the eleven currently recognized species of the green macroalgal genus Rhipilia Kützing has shown that the most useful features for distinguishing species are the disposition and diameters of the blade siphons; tenacular number, position and shape; and the type and location of siphon constrictions. Several attributes that have previously been given major taxonomic weight, such as plant colour, habit (including frond thickness, degree of prominence of concentric markings on the blades, and degree of stipe elongation) and habitat associations do not appear to be sufficiently consistent to be useful in themselves for many species delineations. Two species (Rhipilia diaphana and R. tenaculosa) are placed in synonymy (with R. orientalis and R.tomentosa, respectively). All but the two most recently described species (R. penicilloides and R. nigrescens) are reinvestigated and illustrated, with particular emphasis placed on three (R. sinuosa, R. orientalis and R. crassa A. Millar & Kraft, sp.nov.) that occur along the southern Great Barrier Reef of eastern Australia and in southeastern Luzon, Philippines. Distinguishing features of R. crassa are the lack of clear differentiation between stalk and blade, the relatively large filament diameters (up to 130 μm),the coarse, regularly rectilinear meshworks of the blades, and the large numbers of prongs, some of them forked, on the tenacula.

New Species of Diminutive Scincid Lizard (Squamata; Lygosominae: Sphenomorphus) from Luzon Island, Republic of the Philippines

Sphenomorphus tagapayo is a new species of scincid lizard from Aurora Province, southeastern Luzon Island, Republic of the Philippines. The new species inhabits leaf litter between the elevations of 720 and 1175 m in tropical montane cloud forests along the island's eastern coast. Sphenomorphus tagapayo appears most closely related to Sphenomorphus atrigularis, S. lawtoni, S. biparietalis, S. steerei (differing from all of these by coloration and various morphological characters, most notably a scale-covered tympanum) and S. luzonensis (from which it differs by a much smaller body size, coloration, fewer paravertebrals and greater number of midbody scale rows). The new species is also similar in size, scalation, ecology, and coloration to members of the genus Parvoscincus (P. palawanensis and P. sisoni) but differs from these species by the possession of a single frontoparietal (vs paired frontoparietals), two rows (vs one row) of alternately overlapping supradigital scales, smaller lower eyelid scales (vs a row of columnar-shaped scales covering half of the lower eyelid), higher midbody scale counts, the presence of two (vs one) oviducts, and a brood

Geology and tectonic history of Southeastern Luzon, Philippines

Southeastern Luzon belongs to the eastern Philippine Mobile Belt. Geological and structural studies revealed that it could be divided into three major structural units limited by two subparallel NW-SE trending left-lateral strike-slip faults: the Hilawan Fault in the NE and the Minas Fault in the SW. The North-central Catanduanes Structural Unit (NCSU) is characterized by a Middle to early Late Cretaceous volcanic arc sequence unconformably overlain by a Middle to Late Eocene volcanic arc sequence followed by Early Oligocene intrusives. The Median Structural Unit (MSU), limited from the NCSU by the Hilawan Fault, is underlain by a Late Cretaceous volcanic arc sequence followed by two distinct chaotic sequences from the end of Cretaceous-Paleocene and latest Middle Eocene-earliest Late Eocene. It is limited to the southwest by the Minas Fault. The Western Caramoan Structural Unit (WCSU), pre-Late Cretaceous ophiolitic suite unconformably overlain by Late Cretaceous volcanic arc sequence and Middle Eocene limestones are exposed. These structural units are overlain by carbonate and detrital sequence from the Late Oligocene to Pliocene. Constrained by angular unconformities and deposition of olistostromes, polyphase left-lateral strike-slip faulting was recorded since the end of Cretaceous up to the limit of Early-Late Oligocene. These faults probably represent the traces of a Proto-Philippine Fault System in Southeastern Luzon.

Geology and tectonic history of Southeastern Luzon, Philippines

Abstract Southeastern Luzon belongs to the eastern Philippine Mobile Belt. Geological and structural studies revealed that it could be divided into three major structural units limited by two subparallel NW-SE trending left-lateral strike-slip faults: the Hilawan Fault in the NE and the Minas Fault in the SW. The North-central Catanduanes Structural Unit (NCSU) is characterized by a Middle to early Late Cretaceous volcanic arc sequence unconformably overlain by a Middle to Late Eocene volcanic arc sequence followed by Early Oligocene intrusives. The Median Structural Unit (MSU), limited from the NCSU by the Hilawan Fault, is underlain by a Late Cretaceous volcanic arc sequence followed by two distinct chaotic sequences from the end of Cretaceous-Paleocene and latest Middle Eocene-earliest Late Eocene. It is limited to the southwest by the Minas Fault. The Western Caramoan Structural Unit (WCSU), pre-Late Cretaceous ophiolitic suite unconformably overlain by Late Cretaceous volcanic arc sequence and Middle Eocene limestones are exposed. These structural units are overlain by carbonate and detrital sequence from the Late Oligocene to Pliocene. Constrained by angular unconformities and deposition of olistostromes, polyphase left-lateral strike-slip faulting was recorded since the end of Cretaceous up to the limit of Early-Late Oligocene. These faults probably represent the traces of a Proto-Philippine Fault System in Southeastern Luzon.