We describe a new species of miniaturised Platymantis (subgenus Lahatnanguri) from the Romblon Island Group (RIG), Philippines. Previously, the RIG population was treated as Platymantis pygmaeus, a forestdwelling species endemic to Luzon Island due to morphological, ecological, and acoustic similarities. We conducted phylogenetic analyses using 16S mitochondrial DNA sequences and quantified morphological variation across a statistically robust sample size to assess the distinctiveness of the RIG population. Our results recovered the RIG lineage as monophyletic with moderate support (75% bootstrap; 0.83 BPP). Phylogenetic analyses further demonstrate that Platymantis guiting, new species, is not closely related to P. pygmaeus and it is morphologically distinguished by shorter limb proportions and a stereotyped advertisement call characterised by a single-pulsed, repetitive clicking. Named after Mount Guiting-Guiting, the highest peak on Sibuyan Island, this species stands as a powerful reminder of the biogeographic subregion's fragile and irreplaceable biodiversity. This taxonomic revision highlights the unique herpetological diversity of the RIG and reinforces the need for targeted conservation efforts in this biogeographically significant subregion.

Where and how species are sampled can shape biodiversity knowledge, spatial patterns, and data-driven conservation. In megadiverse regions of the Global South, sampling remains uneven, and available data often lack synthesis needed to assess spatial heterogeneity in recorded biodiversity for conservation planning. This limitation is also evident in areas designated for biodiversity conservation. We examine this in the Philippines, where long-term research effort and policy development have supported expansion of conservation-relevant areas (hereafter "Philippine conservation-relevant areas" or PCAs). Using over a century of digitally accessible species occurrence records compiled and manually curated, we analyzed the country-wide spatial distribution of observed amphibian and squamate reptile species richness. We further tested whether observed richness across PCAs is associated with area, topographic relief, and sampling effort, and whether these relationships differ between protected and conserved areas (with management or governance schemes) and key biodiversity areas (unmanaged but priority areas for conservation). Results show strong spatial heterogeneity in occurrence records, with preserved specimens comprising 92% of all records and strongly influencing observed richness patterns. Citizen-science data tend to reinforce already well-sampled regions, whereas literature-derived records provide additional coverage in comparatively undersampled areas. PCAs show variable representation in the dataset, with observed richness and sampling effort generally increasing with area. However, this richness-area relationship weakens with increasing topographic relief. Differences in predictor-richness relationships between PCA types are also evident, with stronger area and sampling effects in protected and conserved areas and a relatively stronger elevational effect in key biodiversity areas. Notably, several high-richness areas occur outside formally designated protected areas. These results highlight uneven biodiversity data coverage and suggest that observed richness patterns may reflect both sampling structure and spatial variation. We emphasize integrating multiple biodiversity data sources and identifying undersampled regions to improve future biodiversity assessments.

One challenge for species delimitation involves closely related species, characterized by both intra- and interspecifically variable morphologies, for which genetic information is not yet available. One such example is exhibited by agamid lizards of the genus Bronchocela. This group of conspicuously vibrant green lizards is widely distributed in Southeast Asia, with 15 recognized species. However, the geographic distributions of several named taxa have remained unclear because of the imprecise application of names in taxonomic summaries and faunal checklists. For more than a century, many authors have noted that a few species, often considered “widespread,” persist throughout nearly the entire range of the genus. This is particularly true for populations identified as Bronchocela cristatella sensu lato and, to a lesser extent, B. marmorata in the Philippines. In this study, we reassess the systematics and taxonomy of Bronchocela populations in the Philippine archipelago. Using multiple lines of evidence from molecular and morphological data, we uncover four distinct lineages of Philippine Bronchocela, all of which we interpret as being distantly related to B. cristatella sensu lato from Malaysia and Indonesia. We argue that these lineages should now be interpreted as Philippine endemic species. Given the strong congruence in molecular and morphological analyses, we now consider populations from the Luzon faunal region (including Catanduanes, Marinduque, Lubang, and Polillo Islands), Romblon (Tablas, Romblon, and Sibuyan Islands), and the West Visayas (Negros, Cebu, and Panay Islands) as B. marmorata. The nomenclaturally available name, B. philippina, is now designated to the unique lineage from the Mindanao faunal region. Additionally, we recognize two new, distinctive species from the Mindoro (B. carestiai) and Palawan (B. mallarii) faunal regions. Overall, our findings demonstrate how conspicuous and widely distributed species in Southeast Asia remain poorly understood, overlooked, and taxonomically unresolved. Hence, the taxonomic resolution of Bronchocela populations in the island archipelagos of Southeast Asia will greatly benefit from the urgent priority of determining which landmass the name “B. cristatella” applies.

Where and how species are sampled can shape biodiversity knowledge, spatial patterns, and data-driven conservation. In many Global South biodiversity hotspots, sampling remains uneven, and available data often lack the synthesis needed to assess region-wide gaps for effective conservation planning and priority-setting. This shortfall is common within conserved areas and key biodiversity areas (hereafter ‘priority conservation areas’ or PCAs). We demonstrate this case in the Philippines, one of the most biodiverse countries in the world, where longstanding biodiversity research and growing policy momentum support efforts to expand coverage of conserved areas. Drawing on over a century of species occurrence records made digitally accessible, we compiled and manually curated these data to assemble and analyze information on Philippine amphibians and squamate reptiles from multiple sources, assessing the spatial distribution of observed diversity in relation to PCAs. Results reveal strong spatial biases, with preserved specimens comprising the majority of records and largely shaping observed diversity patterns. Citizen-science data complement already well-sampled regions, while records from peer-reviewed literature contribute valuable documentation in poorly sampled areas. PCAs are proportionally well-sampled, although gaps and biases remain. Sampling effort and observed diversity were higher in larger PCAs, but this positive area effect diminishes with increasing topographic relief, highlighting large mountain ranges as persistent blind spots in biodiversity documentation. Notably, some areas of higher diversity occur outside established PCAs. We discuss implications of these biases and propose enabling mechanisms to improve primary biodiversity data collection. This study affirms the importance of integrating digitally accessible biodiversity data from multiple sources in revealing sampling gaps and biases, guiding future studies towards poorly sampled areas and informing conservation priorities. ### Competing Interest Statement The authors have declared no competing interest.

A first review of the history, status, and prospects for Philippine herpetology conducted more than two decades ago (2002) summarized the diverse topics studied and highlighted the development and achievements in research up to the year 2000. This study revisits and re-assesses what Philippine herpetology has accomplished, both as a discipline and a community, during the last two decades (2002–2022). A total of 423 herpetological publications was collated, revealing a substantial increase in annual publications, rising from approximately four per year during 2002–2008 to around 28 per year in 2009–2022. Half of the published studies focused on squamate reptiles (lizards 30.5%, snakes 21%) and 28.4% on amphibians, 5.9% on turtles, and 2.6% on crocodiles. The remaining 11.6% of studies focused simultaneously on multiple taxa (i.e., faunal inventories). Diversity and distribution (35.2%) and ecological (26.5%) studies remained popular, while studies on taxonomy (14.9%), phylogenetics and biogeography (11.8%), and conservation (11.6%) all increased. However, geographical gaps persist urging immediate surveys in many understudied regions of the country. Finally, we found a balanced representation between Filipino and foreign first authors (1.0:1.1), yet a substantial gender gap exists between male and female first authors (7.1:1.0). Nonetheless, the steep increase in publications and the diversity of people engaged in Philippine herpetology is a remarkable positive finding compared to the 20 years preceding the last review (1980–2000). Our hope is that the next decades will bring increasingly equitable, internationally collaborative, and broadly inclusive engagement in the study of amphibians and reptiles in the Philippines.

The establishment of environmental management zones is an important strategy for biodiversity conservation. However, identifying and assigning appropriate zones is a challenging task that is critical to the management’s success. The Environmentally Critical Areas Network (ECAN) of the Palawan province is among the management strategies being implemented in the western Philippines. Under this strategy, natural resources needing the highest degree of protection are designated as core zones (CZ). Our study revisited this strategy to assess the current placement of the core zones with respect to species distributions and vegetation types. We conducted a series of field surveys in four municipalities of Palawan to assess the status of biodiversity. Gathered data was used to identify potential critical habitats by generating species distribution models and performing vegetation analysis using land satellite images. The placement of the CZ was evaluated using the identified critical habitats. Our assessments show that many Palawan endemic species persist despite increasing pressures from anthropogenic activities. We also found that a considerable extent of natural forest remains, generally confined in high elevations and steep terrains. The assessment of critical habitats and CZ revealed vital gaps in protection, suggesting that a revision is necessary to accommodate important habitats of threatened and endemic species. Overall, our study highlights the significance of integrating biodiversity data in improving conservation and management strategies, which has been overlooked in the current ECAN zones.

Amblyomma geoemydae is an oriental tick species primarily associated with turtles and tortoises but also sometimes reported from other vertebrates, including humans. Although A. geoemydae was first reported from the Philippines more than 70 years ago, it has not been reported since, and no local distributional or host data have been published. Herein, we present the first definitive locality report and host record for A. geoemydae in the Philippines. A complete checklist of the known host species from which A. geoemydae has been collected is also presented.

The Philippine mouse deer (Tragulus nigricans) is an endangered ungulate species, endemic to the Balabac Islands in the Palawan Faunal Region of the western Philippines. Despite its conservation importance, it has received little attention from local authorities and conservation biologists, with limited studies conducted on the species. Here we provide a preliminary report on the species distribution, population and conservation status, based on our recently completed surveys. We used a combination of line transect distance sampling, opportunistic searching on targeted habitats, and informal community interviews to assess the species’ status. We recorded a total of 25 sightings of mouse deer during our transect surveys. All records, including recent sightings of mouse deer, were from two islands, mainland Balabac and Bugsuk. No mouse deer were recorded on other islands that we surveyed, suggesting that the populations have been markedly reduced due to a nearly complete conversion of natural habitat, such as Ramos Island, or perhaps some islands are too small to permanently support populations. Our analyses revealed that the species occurs at low density (0.219 ± 0.084/ha), particularly on Balabac. The mean population estimate based on Bayesian analysis is 2525 (95% Highest Density Interval, 1635–3461). However, this number is highly uncertain because of the low probability, highlighting the need for more information on the species’ population. Several conservation efforts are being implemented now, but more intensive in situ conservation programs would benefit the species, along with other threatened endemics found in the region.

Understanding the patterns and drivers of species assemblages is the central tenet of community ecology and this may inform effective conservation and management strategies. Such information is scarce in tropical regions, particularly the Palawan faunal region and island group in the western Philippines. Here we examined the patterns of anuran richness and identified correlations in species co-occurrences and their shared responses to habitat types, water availability, and elevation. We sampled anuran populations using standardized transects established across Palawan's major islands between 2013 and 2019. We generated interpolated and extrapolated richness using Hill numbers. To investigate species co-occurrences and the relative importance of environmental variables, we used Joint Species Distribution Model (JSDM). A total of 18 anuran species were recorded, including seven non-endemic and 11 species restricted to Palawan. Anuran richness was highest in forests habitats than in cultivated land areas. Sites with water sources had higher anuran richness than those without water. Species richness observed along elevational gradient exhibited a hump-shaped pattern. Significant positive correlations in species co-occurrences were found among aquatic and semi-aquatic species. Anuran species showed tight associations with elevation and water availability, indicating that these variables are strong predictors of anuran co-occurrences. Finally, this study broadens our understanding of the differences and similarities in habitat requirements among anuran species, highlighting the need to consider such information when developing conservation strategies other than the traditional vulnerability and irreplaceability measures.

The municipality of Santa Ignacia in the Province of Tarlac is highly dependent on groundwater as its major water supply for various purposes, but there is inconsistency in monitoring groundwater quality in the area which may impact the health of consumers. This study presented the preliminary assessment of groundwater quality through the application of spatial mapping. Out of 6,815 wells in the municipality, groundwater samples were collected from 274 hand pump wells. The measurements of selected groundwater quality parameters such as pH, conductivity, nitrate, nitrite, and iron of groundwater samples were determined on-site. The geographical coordinates of sampled wells and measurements of groundwater quality parameters were used in Geographic Information System software, QGIS, to construct the spatial distribution and spatial variation maps. The values of measured parameters were interpolated using the inverse distance weighted technique to predict the parameters at other sites in Santa Ignacia. Spatial variation maps revealed that the groundwater quality parameters varied in the municipality. All measured parameters, except the nitrite content, were within the acceptable limits set by the World Health Organization for drinking water. The high level of nitrite content in groundwater may be attributed to the application of fertilizers during agricultural activities. The nitrite content of groundwater, which exceeded the permissible limit, may cause long-term public health problems. Hence, an upscale evaluation and monitoring of groundwater quality and existing anthropological activities in the municipality are highly recommended. The identification of other possible source(s) of nitrite is necessary to lessen possible contamination risk and to protect the groundwater sources in the municipality. The results of this preliminary study would be useful in prospect studies of groundwater quality in the study area and in other provinces in the Philippines.

Information on species richness and community structure is invaluable for guiding conservation and management of biodiversity, but is rarely available in the megadiverse biodiversity conservation hotspot of Philippines – particularly for amphibians and reptiles. This study provides the first report and characterisation of amphibians and reptile communities across primary habitat types of the Victoria-Anepahan Mountain Range on Palawan Island along the western edge of the archipelago. A total of 41 amphibian and reptile species were recorded throughout our sampling sites (n = 27 species) or in targeted habitat searches (14 species). A species richness estimator predicted that 35 species may be present in our sampling sites, suggesting that a significant proportion of secretive species may continue to be unrecorded, especially for reptiles. Higher species richness was found in secondary growth than in mixed-use agricultural areas or even pristine forest. The low species richness recorded from pristine forest types may be due to these forests now being restricted to higher elevations where species diversity has been documented to decrease. Our results also show that complex community structures (species assemblages) are to be equally expected in both secondary growth and pristine forests. Together, our results show how species richness and community assemblages may vary across habitats, highlighting that old growth forest does not always support higher species richness, particularly in high elevations.

Snakes of the genus Oligodon Fitzinger, 1826 are rarely observed and infrequently collected in the Philippines. Here we report the rediscovery and first documentation of Oligodon perkinsi (Taylor, 1925) after nearly 60 years. Our observation extends the species distribution to Busuanga, an island located north of Culion (type locality) and on the western side of the archipelago.