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.

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.

We describe a new species of fanged frog (genus Limnonectes) from the foothills of two, inland, south-to-north oriented, parallel mountain ranges of Luzon Island of the northern Philippines. Although the new species broadly cooccurs with its closest relative at numerous localities within the Luzon Pleistocene aggregate island complex faunal region, it can be readily diagnosed from Limnonectes macrocephalus based on its unpigmented (white) ventral surfaces of terminal digital discs, its unexpanded or minimally expanded terminal digital discs, and an allometric growth pattern indicating evidence of sexual dimorphism at a smaller overall body size. The new species, which can also be identified by its divergent 16S ribosomal RNA mitochondrial gene sequence, possesses a curious distribution unlike the range of any Philippine endemic amphibian characterized to date: it is known from nine interior (inland) localities distributed between the two, parallel, south-to-north mountain chains (the Cordillera and Sierra Madre) which characterize mainland Luzon. We interpret the presence of two broadly sympatric, genetically divergent, strongly supported haplotype clades-which correspond to morphologically diagnosable phenotypes, using traditional discrete characters and allometric growth patterns-as prima facia evidence of two, independently evolving evolutionary lineages (species) of giant fanged frogs on Luzon. The description of another new species of large-bodied fanged frog on Luzon from multiple localities in close proximity to the capital city (Manila) emphasizes the degree to which even well-studied larger Philippine landmasses possess unrecognized and overlooked biodiversity.

We measured hardness, modulus of elasticity, and, for the first time, loss tangent, energy of fracture, abrasion resistance, and impact resistance of zinc- and manganese-enriched materials from fangs, stings and other "tools" of an ant, spider, scorpion and nereid worm. The mechanical properties of the Zn- and Mn-materials tended to cluster together between plain and biomineralized "tool" materials, with the hardness reaching, and most abrasion resistance values exceeding, those of calcified salmon teeth and crab claws. Atom probe tomography indicated that Zn was distributed homogeneously on a nanometer scale and likely bound as individual atoms to more than ¼ of the protein residues in ant mandibular teeth. This homogeneity appears to enable sharper, more precisely sculpted "tools" than materials with biomineral inclusions do, and also eliminates interfaces with the inclusions that could be susceptible to fracture. Based on contact mechanics and simplified models, we hypothesize that, relative to plain materials, the higher elastic modulus, hardness and abrasion resistance minimize temporary or permanent tool blunting, resulting in a roughly 2/3 reduction in the force, energy, and muscle mass required to initiate puncture of stiff materials, and even greater force reductions when the cumulative effects of abrasion are considered. We suggest that the sharpness-related force reductions lead to significant energy savings, and can also enable organisms, especially smaller ones, to puncture, cut, and grasp objects that would not be accessible with plain or biomineralized "tools".

The Eurycea bislineata complex ("two-lined salamanders") of eastern North America contains six described species, of which three have very similar morphologies and relatively broad geographic distributions, and three have more divergent morphologies with narrow geographic distributions. Recent molecular phylogenetic analyses found that four of the six species in the complex contain deep genetic structure, and that two of the species (E. cinigera and E. wilderae) are paraphyletic in mitochondrial and nuclear DNA, inferring that current taxonomy does not reflect actual species boundaries in the complex. The member of this complex in the Sandhilis physiographic region of south-central North Carolina, USA, is notable for its distinctive coloration and ecology, and a study on allozymic variation published over 30 years ago demonstrated that it is genetically distinct but clustered within the paraphyletic E. cirrigera. This study investigates the taxonomic status of the Sandhills population using morphology, mitochondria] DNA, and a 21-locus nuclear DNA data set to test if the Sandhills taxon represents a local ecomorph that is conspecific with adjacent populations of E. cirrigera, or if it represents a divergent evolutional), lineage that warrants taxonomic recognition. Mitochondria! and nuclear DNA revealed that the Sandhills taxon is genetically distinct and phylogenetically unrelated to adjacent populations of E. cirrigera. Principal components analysis of 316 adult specimens of the Sandhills taxon and the three morphologically similar species in the complex found considerable overlap among these fain but pairwise comparisons of heavily loading morphological characters showed that the Sandhills taxon usually has a shorter body, shorter tail, and narrower head. Based on these corroborated lines of evidence, the hypothesis that the Sandhills taxon represents only a local ecomorph is rejected and it is described as a new species. Clarification of the extent of its geographic range (including its possible presence in South Carolina), differentiation of larvae from other members of the complex, and verification of hypothesized narrow zones of hybridization with E. cirrigera at the peripheries of its geographic range are needed. The description of the Sandhills taxon brings the number of endemic salamander species in North Carolina to seven. Integrative taxonomic revisions of the E. bislineata complex, particularly E. cirrigera and E. wilderae, are needed to estimate species diversity and distributions of these salamanders more accurately.

Liopeltis is a genus of poorly known, infrequently sampled species of colubrid snakes in tropical Asia. We collected a specimen of Liopeltis from Pulau Tioman, Peninsular Malaysia, that superficially resembled L. philippina, a rare species that is endemic to the Palawan Pleistocene Aggregate Island Complex, western Philippines. We analyzed morphological and mitochondrial DNA sequence data from the Pulau Tioman specimen and found distinct differences to L. philippina and all other congeners. On the basis of these corroborated lines of evidence, the Pulau Tioman specimen is described as a new species, L. tiomanica sp. nov. The new species occurs in sympatry with L. tricolor on Pulau Tioman, and our description of L. tiomanica sp. nov. brings the number of endemic amphibians and reptiles on Pulau Tioman to 12.

A new species of the dicroglossid frog genus Limnonectes is described from recent and historical museum specimens collected in central and southern Laos and northeastern Thailand. Limnonectessavan sp. nov. has males that bear a caruncle on top of the head, and most closely resembles L.dabanus from adjacent southern Vietnam and eastern Cambodia. However, the new species is readily distinguished from L.dabanus, and all other caruncle-bearing species of Limnonectes in mainland Southeast Asia, by its adult and larval morphology, mitochondrial DNA, and advertisement call. Its description brings the total number of caruncle-bearing species of Limnonectes to six.