Zoantharians are among the most abundant non-calcifying hexacorals in shallow-water ecosystems, with colonies of some species capable of covering dozens of square meters across tropical and temperate regions. Despite this ecological prominence, they remain understudied compared with better-known reef groups. The research team combined an extensive literature review with new field surveys conducted by snorkeling and SCUBA diving at depths of 0 to 40 meters across Yucatan, Hong Kong, Cebu, South Africa, Bali, and Kenting, Taiwan. They supplemented these observations with morphological examination and DNA sequence data from specimens held at the Bernice Pauahi Bishop Museum in Hawai’i, the Smithsonian National Museum of Natural History, and the National Museum of Rio de Janeiro.

Two striking results emerged that contrast with previously established marine biogeographical patterns. First, several zoantharian genera are cosmopolitan, inhabiting most biogeographic provinces within and between ocean basins. Although the highest diversity was observed in the Indo-Pacific Ocean, concordant with biogeographic assays of reef fishes and stony corals, the distribution of genera was not significantly different between the Atlantic and the Indo-Pacific. Second, the team identified multiple sibling species complexes between the two basins, pairs or groups of lineages that occupy distinct oceans yet share highly similar DNA sequences and morphology.

The order Zoantharia comprises nine families subdivided into the suborders Brachycnemina and Macrocnemina. Most brachycneminan species host Symbiodiniaceae microalgae, also known as zooxanthellae, and are restricted to shallow waters, while macrocneminans have a broader distribution into the deep sea and polar regions and are mostly azooxanthellate. Several Macrocnemina genera, and one Brachycnemina genus, Acrozoanthus, display epizoic symbioses in which polyps attach to other benthic invertebrates, including crabs, hydroids, octocorals, sponges, or polychaete worm tubes. These associations are often obligatory, with the zoantharian species found only with a specific genus or family of hosts.

The biogeographic analysis revealed that 6 out of the 8 zoantharian families reported in shallow waters are cosmopolitan, with only Nanozoanthidae and Neozoanthidae so far restricted to the Indo-Pacific, though the authors suspect these are also present in the Atlantic. The shallow-water diversity center was the Indo-Polynesian province in the Central Indo-Pacific, while within the Atlantic, the Caribbean province held the highest diversity. In deep waters, a different pattern emerged, with the most diverse provinces being Sino-Japanese, Lusitania, and Hawaiian. Parazoanthidae was the most diverse and widely distributed family, with 16 genera reported across 19 provinces.

To quantify these patterns, the researchers compiled records across global marine biogeographic provinces following the framework of Briggs and Bowen, chosen because its provinces defined by more than 10 percent endemism align well with phylogeographic breaks recovered in fishes and crustaceans. They used the Jaccard dissimilarity index and Unweighted Pair Group Method with Arithmetic Mean to summarize relationships among provinces, and applied non-metric multidimensional scaling to plot similarities in zoantharian composition by ocean basin and seawater temperature. Statistical testing with pairwise Adonis showed no significant differences in the composition of genera and families between the Atlantic and Indo-Pacific, yet tropical and temperate provinces had significant differences, meaning temperature rather than basin separation structures zoantharian communities.

The phylogenetic reconstruction, built from a concatenated alignment of mitochondrial COI and 16S rDNA markers plus nuclear ITS rDNA totaling 120 sequences and 3,219 sites, confirmed that Brachycnemina is monophyletic while Macrocnemina is paraphyletic, with the family Hydrozoanthidae residing within brachycnemic zoantharians. At least four shallow-water families had sibling species complexes. In Brachycnemina, three genera from two families had species reported in both basins: Palythoa from Sphenopidae, and Zoanthus and most likely Isaurus from Zoanthidae. The suborder Macrocnemina had at least two sibling species groups, one from Hydrozoanthidae and another from Parazoanthidae. The sibling pair Palythoa caribaeorum from the Atlantic and Palythoa tuberculosa from the Indo-Pacific had the most extensive distribution among zoantharians analyzed, with reports across all tropical and subtropical provinces.

What explains this puzzling weak genetic differentiation between ocean basins? The authors hypothesize that low or moderate genetic diversity may partially explain the pattern. Anomalously low mutation rates have been observed in a diversity of taxa including plants, cnidarians, and vertebrates, and a low mitochondrial DNA mutation rate may prevail in most anthozoan orders, including stony corals and zoantharians. Hybridization and incomplete lineage sorting may also obscure evolutionary relationships for many Palythoa and Zoanthus lineages. Additionally, many zoantharian lineages have evolved high ecological plasticity, adapting to distinct habitats and environmental settings, with endosymbiosis and epizoism gained and lost multiple times across several distinct genera and families.

At species and population scales, three dispersal strategies may at least partly explain the low levels of genetic differences between ocean basins. A long pelagic larval duration is one factor; research on zoantharian larval phases is limited, but an extended planktonic phase of more than 100 days is known for Palythoa tuberculosa, and plankton tows indicate long larval durations for the families Sphenopidae and Zoanthidae. Asexual reproduction promotes local dispersal and increases substrate occupancy, a trait described for genera such as Palythoa, Parazoanthus, and Zoanthus. Some zoantharians also have high rafting potential, and many coastal organisms, including stony corals and reef fishes, can disperse for hundreds to thousands of kilometers attached to drift material such as volcanic pumice, seaweed, logs, or man-made objects.

The low molecular and morphological divergence observed between zoantharian sibling species may reflect a similar use of resources and related niches. Palythoa tuberculosa is often the most abundant zoantharian in shallow waters of the Indo-Pacific, including Okinawa, Taiwan, Malaysia, and the Red Sea, while its Atlantic sibling Palythoa caribaeorum is widespread along the Brazilian and Caribbean coasts, the Mid-Atlantic Ridge, and the East Atlantic. Both species are generalists found in diverse environments from the backreef moat to the outer reef, and from the intertidal zone to more than 20 meters deep. In contrast, the siblings Palythoa mutuki and Palythoa grandiflora are relatively less abundant and occur most commonly on intertidal reef crests or exposed habitats in both ocean basins. Considering that most zoantharians are widely distributed across regions and might share similar traits, it is unlikely that these sibling species result from ecological differences between the basins. Instead, geological events are the most likely drivers: the rise of the Isthmus of Panama closed the tropical exchange between the Atlantic and Pacific approximately 3.5 million years ago, while the Benguela upwelling zone, starting approximately 2 million years ago, created a cold-water environmental barrier along the South Atlantic coast of Angola, Namibia, and South Africa. The authors note that the closure of the Tethys Sea, a much older event from 20 to 12 million years ago, would have likely resulted in higher genetic differentiation than observed from zoantharian siblings.

Zoantharians are often overlooked in ecological surveys, and their distributions as reported here are still underestimated. There is a paucity of research along the African coasts and Polynesian archipelagos, and great potential for discovering additional species within cryptic habitats such as caves, rubble zones, and turf. The two current Indo-Pacific-endemic families, Nanozoanthidae and Neozoanthidae, are most likely cosmopolitan; Nanozoanthidae species are difficult to spot due to a pale, translucid color and small polyp size under one millimeter, while molecular data suggest Isozoanthus sulcatus off western Europe likely belongs to Nanozoanthidae, and phylogenetic analyses indicate Neozoanthidae should be reassigned to the cosmopolitan family Zoanthidae. Species of Palythoa and Zoanthus play a significant ecological role in phase shifts from coral to zoantharian-dominated reefs, and with ongoing environmental change, such phase shifts may become more common in coral reefs worldwide. Filling knowledge gaps on the distributions and biology of zoantharians will be essential to support monitoring and management of marine ecosystems.

Subject of Research: Global biogeography and sibling species patterns of zoantharian cnidarians between the Atlantic and Indo-Pacific oceans

Article Title: Global biogeography of zoantharians indicates a weak genetic differentiation between the Atlantic and Indo-Pacific oceans, and distinct communities in tropical and temperate provinces

Article References: Santos, M. E. A., Kise, H., Fourreau, C. J. L., Kiriukhin, B., Kitahara, M. V., Baker, D. M., Toonen, R. J., Liu, P. J., Chang, A., Tu, T.-H., Widiastuti, Agustini, K. M. P., Bowen, B. W., & Reimer, J. D. (2026). Global biogeography of zoantharians indicates a weak genetic differentiation between the Atlantic and Indo-Pacific oceans, and distinct communities in tropical and temperate provinces. Frontiers of Biogeography, 19, Article e174247. https://doi.org/10.21425/fob.19.174247

Image Credits: AI Generated

DOI: 10.21425/fob.19.174247

Keywords: zoantharians, biogeography, cnidarians, Atlantic Ocean, Indo-Pacific, sibling species, Isthmus of Panama, Benguela upwelling, larval dispersal, coral reefs, phylogenetics, marine invertebrates

Black corals are among the most striking yet poorly understood groups of marine invertebrates. Despite their common name, living colonies display a remarkable range of colours, and their flexible, chitinous skeletons have been prized for jewellery for centuries. Taxonomically, however, the group has long suffered from fragmented documentation, with type specimens scattered across institutions, historical labels of variable quality, and nomenclatural practices that have shifted dramatically since the nineteenth century. Type specimens, the physical anchors of scientific names, are the single most important resource for resolving questions about what a given species actually is.

The newly compiled catalogue is the product of a systematic re-inventory that began in 2024. Access to the material had been intermittently limited in the years following the 2012 merger, owing to relocation and re-housing of the collections, the retirement of the former collection manager, and later the COVID-19 pandemic. As a result, systematic curation and verification of the Antipatharia holdings were delayed for over a decade. The recent reorganisation enabled researchers to locate and examine every relevant specimen, verifying catalogue numbers, type status, preservation condition and associated documentation.

The collection’s historical depth is extraordinary. The oldest material dates to the early nineteenth century and includes specimens gathered by pioneering collectors such as Philipp Franz Balthasar von Siebold, Jan Cock Blomhoff, François Joseph Cantraine, Franck van Heukelom, Theodoor Gerard Lidth de Jeude and Dirk Samuel Hoedt. Approximately 80 percent of the specimens are preserved in 70 percent ethanol, while the remainder consists largely of dry-preserved historical material, much of it dating from before 1900. Associated preparations, including glass slides and scanning electron microscope mounts, complement the colonies themselves for some specimens.

The geographic heart of the collection beats in the Indo-Pacific. A major portion of the early holdings originates from the Siboga Expedition of 1899 to 1900, which surveyed Indonesia, Timor and the Philippines and remains one of the most important single sources of antipatharian material anywhere in the world. Subsequent twentieth-century acquisitions derive primarily from expeditions in Indonesian waters, including the Snellius I expedition of 1929 to 1930, the Snellius II expedition of 1966 and the Rumphius Biohistorical Expedition of 1990, as well as surveys in the Caribbean and the eastern Atlantic. Roughly half of the nominal taxa represented by type material in the catalogue originate from Indonesia, spanning numerous genera and encompassing both shallow-water and bathyal species.

A central figure in the collection’s scientific history is the early twentieth-century researcher van Pesch, whose monographic treatments of 1910 and 1914 described numerous new taxa, including species, varieties and subvarieties. Because infraspecific ranks such as varieties and subvarieties are rarely used in modern taxonomy, the nomenclatural status and interpretation of several of these names require clarification on a case-by-case basis. The catalogue carefully documents these historical names without proposing any new taxonomic or nomenclatural acts, noting instead where the International Code of Zoological Nomenclature, specifically Article 45.6.4, may allow pre-1961 variety names to be deemed subspecific depending on the original author’s intent.

The re-inventory also revealed the complexities of specimen exchange between institutions. Fragments of type specimens, sometimes called schizotypes, were donated to or received from other museums, particularly the National Museum of Natural History of the Smithsonian Institution in Washington. In several cases, original colonies described in early works are not preserved as complete specimens at Naturalis, although fragments or associated material are present. The authors stress that the absence of an original colony should not be interpreted as loss of the type material; rather, it reflects historical collecting, exchange and curation practices whereby type material or portions thereof were distributed amongst institutions. All specimens listed in van Soest’s 1977 catalogue of the former Zoological Museum Amsterdam were located during the re-inventory, and additional type specimens have since been identified.

Among the most intriguing findings are specimens bearing historical labels reading Mus. de Paris, possibly linked to Lamarck’s species described in 1816, such as Antipathes lacerata, Antipathes radians and Antipathes scoparia. Their presence in Leiden may be connected to a remarkable episode of European history. During the French Occupation of the Netherlands, most of the Kabinet des Stadhouders collection was taken to France in 1795. After the invasion, the Leiden professor S.J. Brugmans was sent to Paris to retrieve these collections, encountering strong resistance from Lamarck himself, who was then working on his Histoire naturelle des Animaux sans vertèbres. The return of the collections was ultimately negotiated with the assistance of Alexander von Humboldt, but Brugmans came back with a collection of mostly duplicates from the Paris Museum. The Lamarck-era specimens now in Leiden may represent original material, though their status cannot be confirmed without archival investigation, and recent examination has identified several of them as octocorals or gorgonians rather than true black corals.

Methodologically, the catalogue follows the World Register of Marine Species for currently accepted names, listing each species under its accepted name alongside the original combination and publication. Locality and label data were transcribed and standardised, with geographic coordinates converted to decimal degrees, while original labels were retained with the specimens whenever present and newly added labels are clearly distinguishable from historical ones. Where discrepancies between sources were encountered, the most recent revisionary treatment or prevailing usage was followed, and any remaining uncertainty is explicitly noted. The authors also caution that specimens labelled as neotype in the collection without a documented published designation should be treated with care until the relevant nomenclatural acts are confirmed, distinguishing between published designations and internal collection annotations.

The significance of this work extends well beyond Leiden. By providing verified and accessible type data, the catalogue supports taxonomic revision, nomenclatural stability and future comparative research on a group whose deep-water representatives are increasingly encountered in seamount and abyssal surveys. The collection combines a historically important Coral Triangle core with a broader modern comparative framework built through later revisionary work, particularly the series of revisions by Dennis Opresko, whose deep-water taxa from Palau, Hawaii, the North Pacific seamounts, the Caribbean, the Gulf of Mexico, the eastern Atlantic and southern high-latitude localities are represented by holotype fragments at Naturalis. Ongoing molecular studies may further clarify the status of several ambiguous historical names. All specimen data are accessible through the Naturalis collection data portal, ensuring that this transparent and verifiable account of two centuries of black coral scholarship will serve researchers worldwide for generations to come.

Subject of Research: Annotated catalogue of black coral (Antipatharia) type specimens at Naturalis Biodiversity Center

Article Title: Collections Unravelled: an annotated catalogue of Antipatharia ( Cnidaria , Hexacorallia ) type material in Naturalis Biodiversity Center

Article References: Bakker, P. A. J., & Samimi-Namin, K. (2026). Collections Unravelled: an annotated catalogue of Antipatharia (Cnidaria, Hexacorallia) type material in Naturalis Biodiversity Center. Zoosystematics and Evolution, 102(3), 817-828. https://doi.org/10.3897/zse.102.192821

Image Credits: AI Generated

DOI: 10.3897/zse.102.192821

Keywords: Antipatharia, black corals, type specimens, Naturalis Biodiversity Center, taxonomy, Siboga Expedition, nomenclature, biodiversity collections, Indo-Pacific, Cnidaria, museum curation, Lamarck

Pteraeolidia is an extraordinary animal even by the flamboyant standards of sea slugs. Members of the family Facelinidae, these aeolid nudibranchs can grow up to 300 millimetres long, care for their offspring, and, most remarkably, farm living algae inside their own bodies. The algae in question are zooxanthellae, dinoflagellates of the family Symbiodiniaceae, the same group that powers coral reefs. The slugs acquire them horizontally by feeding, and once ingested the symbionts are taken up into the cells of the digestive gland, where they photosynthesise, multiply and provide their hosts with a solar-powered energy supply. Juveniles that have not yet acquired their algae are almost completely white; colour returns as the internal gardens become established, which is why the appearance of these animals depends so heavily on the concentration of symbionts in their tissues.

For decades the genus was considered taxonomically simple. A revision in 1982 treated Pteraeolidia ianthina as the single valid species and folded P. semperi and P. scolopendrella into it as synonyms. Later work chipped away at that consensus. Wilson and Burghardt established in 2015 that P. ianthina is actually restricted to its type locality, Sydney Harbour, and subsequent molecular surveys uncovered hidden genetic diversity across the Indo-Pacific. What was missing was a detailed, integrative look at any one region, combining DNA barcodes, nuclear markers and anatomy in a single framework. The new study provides exactly that for Vietnam, where the sea slug fauna remains remarkably underexplored; a single review had identified only about 120 sea slug species in Vietnamese waters, far fewer than neighbouring regions of the Indo-West Pacific.

Between 2016 and 2023, researchers from the Vietnamese-Russian Tropical Centre collected 35 specimens by scuba diving at depths of two to 16 metres from five localities spanning central and southern Vietnam: Nha Trang, Phan Rang, Binh Dinh, Tho Chu and the Spratly Islands. Each animal was photographed alive and preserved in 96 percent ethanol, and DNA was extracted from small pieces of foot muscle. The team amplified fragments of two mitochondrial markers, the standard animal barcode gene COI and the ribosomal 16S rRNA gene, plus one nuclear marker, histone H3, producing alignments of 671, 471 and 338 base pairs respectively. Sequences were checked for pseudogenes by translation into amino acids, verified against GenBank, and analysed with Bayesian and maximum-likelihood phylogenetic methods alongside the automatic species-delimitation algorithm ASAP and TCS haplotype networks.

The results were striking. The Vietnamese specimens split into two deeply divergent clades, designated Clade A and Clade B, both recovered with maximal or near-maximal statistical support. Their mitochondrial COI sequences differ by more than 30 percent, an abnormally high figure for animals within a single genus, and 16S shows comparable divergence. Nuclear data told a more discriminating story: the H3 sequences of the two clades are separated by ten fixed nucleotide substitutions, roughly three percent pairwise divergence. Because H3 is biparentally inherited, such fixed differences between animals living side by side are strong evidence of restricted gene flow and hence reproductive isolation. In other words, the two clades are not merely genetically colourful populations of one species; they are independent evolutionary lineages that do not interbreed, even where they occur in sympatry at Nha Trang.

The species-delimitation analysis, meanwhile, exposed just how messy the bigger picture is. Rather than one clean barcoding gap separating within-species from between-species variation, the ASAP algorithm identified four, yielding estimates that ranged from six to as many as 20 molecular operational taxonomic units depending on the distance model used. Vietnamese animals fell into four of these MOTUs, three within Clade A and one within Clade B. Within each clade, mitochondrial divergence is itself enormous: the maximum distance inside Clade A nearly equals the minimum distance between the two clades, a symptom of substitution saturation in which the COI signal has effectively become scrambled by repeated mutations. Notably, one unit within Clade B, MOTU20, corresponds to true P. ianthina from Sydney Harbour, which the authors confirm is a valid species best kept separate from the P. semperi complex altogether.

Can the eye tell the two Vietnamese lineages apart? Largely yes, though with caveats. Clade A animals are darker, with an almost opaque body ranging from pale beige to dark orange, rows of zooxanthellae visible just beneath the epidermis, continuous lemon-coloured patches on the head running into the oral tentacles, and three to five purple rings on each tentacle. Clade B animals are semi-transparent, cream-violet or beige-brown, dotted with white or yellow pigment spots, often with bushier cerata arranged in several rows rather than one, and usually just two distinct purple rings on the tentacles. The authors suggest the colour difference may reflect the depth at which the symbionts sit within the tissues. Internally, however, the two clades are anatomically near-identical: the triangular jaws, the uniserial radula with its characteristic rows of cusps, and the diaulic reproductive system show no consistent differences. Since the original P. semperi was described from alcohol-bleached specimens, direct colour comparison with the type material is impossible, adding a further layer of taxonomic difficulty.

The most provocative finding concerns the runaway evolution of the mitochondrial genome. The extreme divergence is concentrated in Clade A, which sits on a long, unstable branch in COI trees, while nuclear H3 divergence remains at levels typical for closely related aeolid species. The authors argue this pattern is best explained by an accelerated mitochondrial mutation rate, and they propose a tantalising hypothesis: the photosymbiotic lifestyle itself may be the driver. Mitochondrial respiratory genes could be under unusual selective pressures in an animal packed with oxygen-producing algae, or, alternatively, the high tissue oxygen levels generated by photosynthesis may flood cells with reactive oxygen species that overwhelm DNA repair systems and boost mutagenesis, affecting not only protein-coding genes but ribosomal RNA as well. Similar mitochondrial hyperdiversity linked to symbionts has been documented in amphipods, periwinkles and other nudibranchs, but the idea that photosymbiosis might accelerate mtDNA evolution in sea slugs remains preliminary and will require whole-genome data to test properly.

The biogeographic analysis adds a final flourish. Haplotype networks built from COI sequences, including data mined from GenBank across the Indo-West Pacific, show strong geographic structure: haplogroups from Egypt, Fiji, Hawaii, Singapore and Sydney each form distinct clusters, while peripheral regions such as Hawaii and Egypt host only single, genetically isolated haplogroups. The greatest diversity clusters around the Coral Triangle, the recognised epicentre of marine biodiversity, and spills into nearby Vietnamese waters, where Nha Trang alone hosts both clades. Borderline sites track their neighbours: Tho Chu samples resemble those from Singapore, and Spratly specimens sit close to haplotypes from Sulawesi. The Sydney haplogroup stands apart from all other Australian samples, corroborating the status of P. ianthina as a local endemic.

What the study ultimately delivers is a sobering lesson for biodiversity science wrapped in a dazzling package. A single, familiar name applied across half an ocean’s worth of reefs conceals at least two reproductively isolated species in Vietnam alone, and likely many more across the Indo-Pacific, with mitochondrial DNA too fast-evolving and too saturated to count them reliably on its own. The authors argue that rapid nuclear markers and, eventually, genomic-scale data are essential to resolve species limits in a genus whose mitochondria refuse to behave. For now, the Blue Dragon keeps most of its secrets, but Vietnam’s waters, at least, are home to more dragons than the history books recorded.

Subject of Research: Cryptic species diversity and accelerated mitochondrial evolution in the Pteraeolidia semperi nudibranch complex from Vietnam

Article Title: Dragons guard secrets: integrative systematics of Pteraeolidia semperi species complex ( Gastropoda , Nudibranchia ) from Vietnam

Article References: Meshik, M. N., Antokhina, T. I., Deart, Y. V., Chichvarkhina, O. V., & Ekimova, I. A. (2026). Dragons guard secrets: integrative systematics of Pteraeolidia semperi species complex (Gastropoda, Nudibranchia) from Vietnam. ZooKeys, 1293, 347-376. https://doi.org/10.3897/zookeys.1293.195366

Image Credits: AI Generated

DOI: 10.3897/zookeys.1293.195366

Keywords: nudibranch, Pteraeolidia, cryptic species, sea slug, photosymbiosis, zooxanthellae, mitochondrial DNA, Vietnam, molecular taxonomy, Indo-Pacific, species delimitation, marine biodiversity

Philotrypesis is one of the most species-rich genera of non-pollinating fig wasps, belonging to the tribe Otitesellini within the family Pteromalidae. Its females oviposit from outside the fig syconium, usually after pollination and near the end of fig development, driving their long ovipositors through the fig wall into individual ovules. The length of that ovipositor relative to the thickness of the fig wall appears to be a major ecological constraint shaping host use and diversification. Males are generally wingless, often highly polymorphic, and engage in intense competition for mates, sometimes fighting, sometimes adopting alternative reproductive tactics. The genus currently comprises 45 described species, but decades of collecting across more than 2,000 fig samples from roughly 160 host fig species have yielded over 250 putative species, nearly 220 of which appear to be new to science.

The problem with Philoverdance began almost as soon as it was named. The genus was created to accommodate Philoverdance ravii, a distinctive wasp reared from figs of Ficus tinctoria in India, distinguished by a more compact body, less elongate terminal metasomal tergites, monodentate mandibles, a shorter pronotum and smoother body sculpture. Yet all of the diagnostic apomorphies of Philotrypesis were present, and overlap between these distinguishing characters and variation within Philotrypesis was soon noted. A single earlier molecular analysis using Sanger sequencing had recovered Philoverdance within a well-supported Philotrypesis clade, rendering Philotrypesis paraphyletic, but the position remained weakly supported and the question lingered for over a decade.

To settle the matter, the researchers turned to phylogenomics. They sequenced whole genomes of multiple Philotrypesis species on an Illumina NovaSeq 6000 platform, de novo assembled the reads, and extracted single-copy orthologous genes using BUSCO with the hymenoptera_odb12 lineage dataset. A total of 2,471 genes present in at least 90 percent of samples were retained, aligned with MAFFT, trimmed, and concatenated into a supermatrix for maximum-likelihood analysis in IQ-TREE2 with partitioned models and ultrafast bootstrap support. The resulting phylogeny subdivided the sampled Oriental diversity into approximately ten well-supported species groups, and Philoverdance was recovered nested within Philotrypesis with strong support, confirming that it should be treated as the Philotrypesis ravii species group rather than a separate genus.

The team also generated DNA barcodes for the 5′ region of the mitochondrial cytochrome c oxidase subunit I gene, either recovered from whole-genome sequencing data or amplified by PCR and sequenced with Oxford Nanopore Technologies. For the nanopore approach, PCR products were pooled with amplicons from a larger experiment, purified, prepared using the ligation sequencing protocol, and loaded onto Flongle flow cells. Basecalling with the super-accurate model, demultiplexing, removal of unique molecular identifiers and primers, and clustering with VSEARCH at a 0.90 similarity threshold produced consensus sequences that were merged when sharing more than 98 percent identity. Only dominant meta-consensus sequences supported by more than 100 reads and matching congeneric species in NCBI at at least 90 percent identity were retained, providing a reference framework for future species identification.

COI barcoding recovered five well-defined lineages within the Philotrypesis ravii species group, with pairwise genetic distances ranging from 6.1 percent between the most closely related taxa to 8.4 percent between the most divergent. These values substantially exceed those commonly reported among closely related species of Hymenoptera and Pteromalidae and greatly surpass typical intraspecific variation. Combined with consistent morphological differences, the genetic evidence strongly supports recognition of all five lineages as distinct species. The team described four new species: Philotrypesis minang from Sumatra, P. bannaensis from southern China, P. paiwan from Taiwan, and P. arfak from West Papua, joining the previously known P. ravii from India.

The COI topology revealed a pronounced phylogeographic structure within the group. A western lineage comprises P. bannaensis, P. ravii and P. minang, all associated with Ficus tinctoria subsp. gibbosa, the western representative of the host fig complex that extends from Sri Lanka and India through southern China and mainland Southeast Asia to western Malesia. An eastern lineage comprises the sister species P. paiwan from Taiwan and P. arfak from West Papua, both associated with Ficus tinctoria subsp. tinctoria, a widespread Indo-Pacific subspecies ranging from Taiwan and eastern Malesia to New Guinea, the Pacific Islands and northern Australia. Although based on more limited taxon sampling, the BUSCO phylogeny independently supports this same major evolutionary split between western and eastern lineages.

Remarkably, this geographic partition is mirrored by morphology. The eastern species share a suite of characters including a ventrally orange metasoma, a sculptured mesoscutellum and relatively elongate ovipositor sheaths, whereas the western species generally possess a dark ventral metasoma, a smooth mesoscutellum and shorter ovipositors. The concordance among mitochondrial data, genomic data, morphology, geography and host-plant subdivision provides compelling evidence that the P. ravii species group consists of several independently evolving species whose diversification has been shaped by the historical biogeography of the Ficus tinctoria complex across the Indo-Pacific region.

An equally interesting pattern emerges when ovipositor length is examined within each lineage. In the western lineage, the southern Chinese P. bannaensis and the Indian P. ravii possess relatively short ovipositors, whereas the Sumatran P. minang exhibits a much longer one. A similar trend appears in the eastern lineage, where the Taiwanese P. paiwan has a shorter ovipositor than its Papuan sister species P. arfak. Although direct measurements of syconium size and wall thickness across geographic populations of Ficus tinctoria are currently lacking, this repeated pattern is suggestive of parallel ecological adaptation to local host traits, consistent with previous findings in other Ficus-associated wasp lineages where ovipositor length relative to fig wall thickness constrains host use.

The study provides diagnoses, descriptions and identification keys for females and males of all five species, along with a first phylogenetic framework for Philotrypesis that will facilitate future taxonomic revision of this exceptionally species-rich and still poorly known genus. The authors note that the male-based key remains provisional, as some species are currently represented by few specimens and accurate identification often relies on morphometric measurements. Nevertheless, the integration of genomic, mitochondrial, morphological and biogeographic evidence demonstrates how a lineage once considered a genus in its own right is better understood as a morphologically distinctive but deeply nested species group, one whose diversification tracks the fragmentation and expansion of its host fig populations across one of the most biogeographically complex regions on Earth.

Subject of Research: Phylogenomics and taxonomy of non-pollinating fig wasps associated with Ficus tinctoria

Article Title: Testing the generic status of Philoverdance and revising the Philotrypesis ravii species group ( Otitesellini , Pteromalidae ) associated with Ficus tinctoria ( Moraceae )

Article References: Li, Y.-R., Cruaud, A., Nidelet, S., Peng, Y.-Q., & Rasplus, J.-Y. (2026). Testing the generic status of Philoverdance and revising the Philotrypesis ravii species group (Otitesellini, Pteromalidae) associated with Ficus tinctoria (Moraceae). Journal of Hymenoptera Research, 99, 915-954. https://doi.org/10.3897/jhr.99.205393

Image Credits: AI Generated

DOI: 10.3897/jhr.99.205393

Keywords: Philotrypesis, Philoverdance, fig wasps, Ficus tinctoria, phylogenomics, COI barcoding, BUSCO, Otitesellini, Pteromalidae, new species, biogeography, Indo-Pacific

The new study, published in the Journal of Micropalaeontology, analyzed 35 surface sediment samples collected from nine locations spanning the Java Sea, the Sunda Strait, the Makassar Strait, the Sumba Strait, waters near Simeulue Island, and offshore Papua. The samples cover an extraordinary bathymetric range, from beach-face sands at zero depth to lower bathyal muds more than 4,300 meters below the surface. By cataloguing which foraminiferal species live where, the team built the first comprehensive, statistically validated set of depth-indicator species for the tropical Indo-Pacific, a region whose deep-sea biodiversity has long remained under-sampled compared with temperate Atlantic and Mediterranean waters.

The central finding is a clean confirmation of a decades-old ecological idea known as the TROX model, short for TRophic-OXygen. Proposed in the mid-1990s, the model predicts that in shallow marine settings, foraminiferal communities are governed mainly by physical forces such as wave energy, substrate type, and hydrodynamic disturbance, whereas in deeper waters, biogeochemical factors such as dissolved oxygen and the flux of organic food take over as the dominant controls. Until now, the model had been validated only in cooler temperate seas. The Indonesian data show that the same fundamental transition operates in the tropics, with the pivotal shift occurring around the outer neritic zone at the continental shelf edge.

The statistical machinery behind the conclusion was rigorous. The researchers combined indicator value analysis, which scores how faithfully a species is concentrated in a particular environment, with detrended correspondence analysis, an ordination technique that arranges samples along environmental gradients, and hierarchical clustering based on Bray-Curtis dissimilarity. Together, these methods discriminated the assemblages with 89 percent classification accuracy across six bathymetric zones: transitional, inner neritic, middle neritic, outer neritic, upper bathyal, and lower bathyal. Detrended correspondence analysis confirmed that water depth was the primary structuring gradient, with the first axis correlating strongly with depth and explaining the majority of the variance in the community data.

One of the most striking quantitative results involves the ratio of planktonic to total foraminifera, a metric micropaleontologists abbreviate as %P. Planktonic foraminifera float in the open water column, so the proportion of their shells among the seafloor fauna rises as the water gets deeper and benthic species become scarcer. In the transitional beach environments of this study, %P was essentially zero, ranging from 0 to 0.6 percent. By the lower bathyal zone, it exceeded 90 percent, peaking at 97 percent. The relationship follows a clean exponential curve with depth, expressed by the equation %P equals the natural logarithm of depth multiplied by 12, and it explains 86 percent of the variance. In practical terms, this gives geologists a ready-made depth gauge: measure the planktonic percentage in a fossil assemblage, and you can estimate the ancient water depth.

Species richness told a complementary story. Benthic diversity climbed from the harsh transitional zone, where only 10 to 16 species per sample survived the pounding surf, to a peak of roughly 120 species in the middle neritic zone, with the single richest sample yielding 47 species at 84 meters depth. Beyond that ecological optimum, benthic richness declined steadily as oxygen dwindled and pressure mounted. Planktonic richness, by contrast, increased continuously with depth, from one or two species in the shallows to 17 to 23 species in the deep basins, where keeled, heavily built forms such as Globorotalia dominate over the globular species typical of nearshore waters.

The indicator species themselves form a vivid ecological cast list. In the high-energy transitional zone, robust genera such as Amphistegina, Calcarina, and Sphaerogypsina dominate, but the researchers caution that these are largely transported corpses, winnowed shoreward from their true neritic habitats by waves and currents. The inner neritic zone splits into two distinct communities depending on the seafloor: fine sands host Ammonia, Asterorotalia trispinosa, and Elphidium hispidulum, while silty bottoms favor agglutinated forms such as Haplophragmoides. The middle neritic zone belongs to Quinqueloculina seminulum and Pseudorotalia. Farther out, Brizalina aenariensis, Gyroidina broeckhiana, and Cibicides mark the outer shelf, where oxygen first emerges as a limiting factor. On the upper slope, infaunal specialists such as Bulimina marginata and Uvigerina asperula take over, and in the deepest samples, Lenticulina orbicularis, Uvigerina peregrina, and the dysoxia-tolerant Globobulimina pacifica rule the mud.

These ecological assignments carry direct consequences for reading the rock record. Because fossil foraminifera are abundant, well preserved, and depth-specific, oil companies and academic geologists routinely use them to reconstruct ancient depositional environments. But most existing calibration schemes were built from Atlantic and Mediterranean data, and this study shows that tropical Indo-Pacific assemblages follow their own regional patterns. The Indonesian team found, for example, that substrate type can override depth as the primary control within the inner neritic zone, meaning that two communities at identical depths can look completely different if one sits on sand and the other on silt. Accurate paleobathymetry in shelf settings therefore requires integrating assemblage data with grain-size analysis and other sedimentological evidence rather than relying on species lists alone.

The deep-water results were, in some ways, even more revealing. Upper bathyal samples from different basins split into isolated clusters, apparently reflecting regional oceanographic differences such as the position and intensity of the oxygen-minimum zone and the complex circulation imposed by the Indonesian Throughflow. Lower bathyal samples, however, grouped together cleanly, distinguished by their very high planktonic percentages and characteristic deep-water taxa. This suggests that beyond roughly 1,000 meters, the steep environmental gradients of oxygen, pressure, temperature, and food supply make deep-sea assemblages easier to classify than their shelf counterparts, a reassuring result for anyone attempting to reconstruct ancient slope and basin deposits.

The authors are candid about the limitations of their dataset. Organic carbon flux and dissolved oxygen, the two central variables of the TROX model, were not measured directly at the sampling sites, and the counts represent total assemblages of living and dead shells rather than stained living communities, introducing potential biases from post-mortem transport and time averaging. Future work, they note, should incorporate field geochemical measurements, metabolic tracers such as Rose Bengal staining, and water-column profiles to sharpen the calibration. Even so, the framework they have established, spanning six depth zones from beach to bathyal depths across the Indonesian seas, offers scientists a locally tuned toolkit for decoding millions of years of tropical marine history. Every core drilled through an Indonesian sedimentary basin now comes with a richer, more precise dictionary for translating its microscopic fossils into ancient depths, ancient oxygen levels, and ancient currents.

Subject of Research: Benthic foraminiferal assemblages as paleobathymetric and paleoenvironmental proxies in Indonesian seas

Article Title: Benthic foraminiferal assemblages as proxies for paleoenvironmental indicators in the Indo-Pacific (Indonesia)

Article References: Fitriany, R., Maryunani, K. A., Putra, P. S., Nugroho, S. H., & Ardhyastuti, S. (2026). Benthic foraminiferal assemblages as proxies for paleoenvironmental indicators in the Indo-Pacific (Indonesia). Journal of Micropalaeontology, 45(1), 487-512. https://doi.org/10.5194/jm-45-487-2026

Image Credits: AI Generated

DOI: 10.5194/jm-45-487-2026

Keywords: foraminifera, micropaleontology, paleobathymetry, Indonesian seas, TROX model, benthic ecology, planktonic percentage, bathymetric zonation, indicator species, Indo-Pacific, oceanography, paleoenvironmental reconstruction

The scale of the challenge is what makes the transition so dramatic. India is among the world’s fastest-growing energy consumers, with an expanding economy, a rising middle class, and hundreds of millions of people whose demand for electricity, transport, and industrial goods continues to climb. For decades, that growth has been fueled overwhelmingly by coal and imported oil, leaving the country exposed to price volatility, supply disruptions, and the mounting physical risks of climate change. The research frames India’s push into renewables as a deliberate attempt to break this dependence, coupling long-term energy security with the climate commitments the country has made on the international stage. In this reading, every gigawatt of solar capacity installed is simultaneously an environmental measure, a balance-of-payments decision, and a geopolitical signal.

Technically, the transition rests on a portfolio of technologies rather than a single silver bullet. Solar photovoltaics and onshore wind form the backbone of current expansion, exploiting India’s exceptional solar irradiance across the subcontinent and strong wind corridors in states such as Gujarat and Tamil Nadu. Hydropower contributes dispatchable generation and grid stability, while nuclear energy offers a low-carbon baseload option that can complement the intermittency of renewables. Perhaps the most forward-looking element is green hydrogen—hydrogen produced by electrolysis powered with renewable electricity—which the study identifies as a potential pillar of future industrial decarbonization, particularly for sectors like steel, fertilizers, and long-haul transport that cannot easily be electrified directly. Together, these technologies aim to reduce fossil fuel dependence while maintaining the reliability that a modern economy demands.

The geopolitical upside of this build-out, according to the analysis, is already visible. Expanding renewable capacity enhances India’s standing as a global climate leader, giving New Delhi moral and diplomatic weight in international negotiations that it historically lacked as a major coal consumer. The study highlights how the clean energy agenda strengthens strategic partnerships, pointing specifically to India’s participation in the Minerals Security Partnership, a multinational initiative designed to secure responsible and diversified supply chains for the critical minerals that underpin batteries, wind turbines, and electric vehicles. It also supports regional cooperation in the Indo-Pacific, where energy infrastructure, maritime trade routes, and technology transfer increasingly intertwine with security policy. In effect, clean energy becomes a diplomatic instrument, allowing India to deepen ties with partners who share both its climate goals and its interest in balancing regional influence.

Yet the same technologies that promise independence create new dependencies, and this is where the study’s critical edge lies. The renewable energy sector is built on a supply chain that is strikingly concentrated. Critical minerals—lithium, cobalt, nickel, and the rare earth elements essential for permanent magnets in wind turbines and electric motors—are mined and processed in a handful of countries, and India possesses limited domestic production of most of them. The paper identifies dependence on imported critical minerals as a central vulnerability, one that could substitute a new form of resource insecurity for the old one. Where the twentieth century saw nations compete for oil fields, the twenty-first may see them compete for lithium brines, cobalt concessions, and rare earth processing plants, and India enters that competition as a relative newcomer.

Technological reliance compounds the mineral problem. The study explicitly discusses India’s technological dependence on China, which dominates not only mineral refining but also the manufacturing of solar photovoltaic modules, battery cells, and many of the intermediate components that make up a modern renewable energy system. Even if India installs vast solar capacity, a significant share of the value chain—from polysilicon to wafers to finished panels—runs through factories beyond its borders. This concentration gives an exporting country considerable leverage, whether through pricing, export controls, or simple market dominance, and it means that a disruption in one country’s industrial output could ripple through India’s entire decarbonization schedule. Supply chain vulnerability, the authors argue, is therefore not a peripheral technical detail but a core strategic risk that must be managed alongside the transition itself.

Beyond materials and manufacturing, the paper catalogues a set of governance and security challenges that emerge during the shift itself. Geopolitical competition over clean energy markets and technologies is intensifying, with major powers racing to set standards, capture industries, and secure influence in energy-importing regions. Policy coordination within India presents its own difficulties: energy policy spans central ministries, state governments, regulatory bodies, and public utilities, and aligning their incentives around a coherent transition pathway is a formidable institutional task. The study also flags energy security concerns during the transition phase—a period in which the country must keep the lights on for a growing economy while simultaneously retiring or reducing fossil fuel capacity, scaling up renewables, and building the storage and grid infrastructure that variable generation requires. Managing that balancing act without compromising reliability is arguably the hardest engineering and political problem of the entire endeavor.

What emerges from the analysis is a picture of transition as strategy. The authors argue that India’s clean energy shift is not merely an environmental objective but a geopolitical process shaped by global power dynamics and technological transformation. That framing carries real implications for how the transition should be pursued. If the goal is only emissions reduction, the cheapest and fastest route might involve maximum imports of Chinese panels and batteries. But if the goal is also strategic autonomy, then domestic manufacturing, mineral diversification, technology partnerships, and stockpiling become integral parts of energy policy rather than industrial policy afterthoughts. The study suggests that India’s leaders must weigh these trade-offs explicitly, because decisions made now about supply chains and industrial capacity will determine how much leverage others hold over India’s energy future for decades.

The regional dimension adds another layer of complexity and opportunity. The Indo-Pacific has become the arena where energy, trade, and security interests converge, and India’s renewable expansion positions it to cooperate with neighbors on grid interconnections, green hydrogen trade, and shared technology standards. Such cooperation can anchor India’s role as a provider of clean energy solutions to the developing world, reinforcing the climate leadership the study describes. At the same time, the region is home to intense competition among major powers, and energy infrastructure projects are increasingly viewed through a strategic lens. India’s ability to translate renewable capacity into regional influence will depend on whether it can offer partners reliable technology, financing, and expertise—capabilities that, in turn, depend on resolving the very supply chain and manufacturing vulnerabilities the paper identifies.

Ultimately, the research offers a sober but constructive assessment. India’s transition toward clean energy is portrayed as a genuine transformation of its economic, environmental, and geopolitical landscape—an undertaking comparable in ambition to any in the country’s modern history. The opportunities are substantial: enhanced global standing, stronger strategic partnerships, reduced fossil fuel exposure, and a leadership role in the technologies of the coming century. The risks are equally real: imported mineral dependence, technological reliance on a single dominant supplier, fragile supply chains, and the delicate task of maintaining energy security mid-transition. The study’s central message is that these two sides cannot be separated. How India manages the interplay between decarbonization and geopolitics will shape not only its own future but the broader architecture of global power in an era when the energy systems of nations—and the influence that flows from them—are being rebuilt from the ground up.

Subject of Research: The geopolitical dimensions of India's clean energy transition

Article Title: India’s transition towards clean energy and its emerging geopolitical implications

Article References: Adsul, A. S., Jaybhaye, R. G., & Lad, R. M. (2026). India’s transition towards clean energy and its emerging geopolitical implications. Discover Sustainability. https://doi.org/10.1007/s43621-026-04496-9

Image Credits: AI Generated

DOI: 10.1007/s43621-026-04496-9

Keywords: India, clean energy, geopolitics, renewable energy, energy security, critical minerals, green hydrogen, solar power, supply chains, Indo-Pacific, climate policy, China

Larger benthic foraminifera, or LBF, are marine protists with complex, often coin-sized shells that host photosynthetic symbionts and thrive in sunlit shallow-water carbonates. Because their shells evolved rapidly and are abundant in drill cores and outcrops, miogypsinids have served for decades as biostratigraphic markers for upper Oligocene to middle Miocene deposits from the Mediterranean to Southeast Asia and Central America. But their taxonomy has been notoriously tangled. Generations of researchers relied on morphometric measurements, particularly the number of chambers in the early whorl of the shell, to define species, sometimes without verifying the underlying shell architecture that distinguishes one genus from another.

An international team led by Davide Bassi of the University of Ferrara, together with Juan Carlos Braga of the University of Granada, Shunichi Kinoshita of Fukui Prefectural University, Johannes Pignatti of Sapienza University of Rome, and Yasufumi Iryu of Tohoku University, went back to the source. They re-examined the original type specimens described by Shoshiro Hanzawa in 1940 from drill cores on Kitadaito Jima, a small island in the Philippine Sea, preserved at Tohoku University Museum in Sendai. Using a Zeiss Xradia 510 Versa micro-computed tomography system at the University of Granada, the team produced three-dimensional renderings at submicron resolution, with true spatial resolution of 0.7 micrometers and voxel sizes down to 70 nanometers, revealing internal canal systems, chamber walls, and apertural structures that thin sections alone had obscured for more than eighty years.

The CT scans delivered a decisive verdict on Miogypsinella borodinensis, the type species of the genus Miogypsinella. The scans revealed a suite of diagnostic features, including a cover on the intraseptal interlocular space, an apertural lip, subsutural canals, a septal flap, and a primary spiral canal with vertical branches extending only to the ventral side of the shell. These characters confirm that Miogypsinella is a valid genus, distinct from the closely related Miogypsinoides, whose members possess thick lamellar lateral walls and canal systems on both sides of the test. The team formally designated a lectotype from Hanzawa’s thin sections to stabilize the species name, and showed that Miogypsinella borodinensis is genuinely different from Miogypsinoides complanatus, a species with which it had been repeatedly confused.

Compiling every reliably illustrated occurrence of these foraminifera worldwide, the researchers traced a remarkable biogeographic story. Two species, Miogypsinella borodinensis and Miogypsinella ubaghsi, were widespread across the central Indo-Pacific, appearing in the Chattian stage of the late Oligocene at localities including Kitadaito Jima, Saipan, Chichi Jima, northeastern Borneo, and Eniwetok Atoll. But Miogypsinella borodinensis also turned up in eastern Mexico, Jamaica, and Antigua, having never been recorded in the Mediterranean or western Tethys. The most plausible explanation, the authors argue, is that Pacific larvae or propagules rode eastward currents all the way to Central America, a dispersal route well documented for corals, coralline algae, and other shallow-water benthic organisms of the same interval.

This eastward migration carries a big implication. For decades, paleontologists assumed that the Oligocene larger foraminifera of the Americas formed a distinctly isolated fauna, cut off from the Indo-Pacific realm. The new evidence shows otherwise: the American Oligocene faunas were not largely isolated as previously thought, and at least one genus arrived from the Pacific rather than originating in the Caribbean. In Central America, Miogypsinella borodinensis gave rise to a descendant, Miogypsinella bermudezi, originally described from early Miocene deposits of Cuba, which differs from its ancestor in having a smaller proloculus, more nepionic chambers, and a nearly horizontal early whorl. The team also rejected hypotheses placing the family’s origin in Central America or the Mediterranean, noting that no confidently identified Miogypsinella specimens have ever been found in Mediterranean Oligocene or early Miocene carbonates.

The study also rehabilitated a second forgotten species. Miogypsinoides lateralis, described by Hanzawa from the same Kitadaito Jima cores, had been shuffled between synonyms for half a century and lumped with species such as Miogypsinoides bantamensis and Miogypsinoides dehaartii, largely because its low number of nepionic chambers resembled other forms. The CT analysis confirmed it as a clearly distinct species, and one with an awkward implication for the field’s guiding paradigm. Since the 1930s, miogypsinid evolution has been framed by nepionic acceleration, a trend in which the number of early chambers progressively decreased through time, allowing species to be ordered along a supposed lineage. Miogypsinoides lateralis breaks the pattern: its morphometric values resemble those of the much younger Burdigalian to Langhian species Miogypsinoides indica, yet it lived earlier, in the Aquitanian. It is, the authors conclude, an exception to the presumed morphological trend within the Miogypsinoides lineage.

Then came the extinction. The last known occurrences of Miogypsinella borodinensis, Miogypsinella ubaghsi, Miogypsinella bermudezi, and Miogypsinoides lateralis all cluster near the end of the Aquitanian, around 20 million years ago. That timing coincides with two major environmental upheavals. First, the ongoing collision of Australia with Southeast Asia and the Philippine Sea Plate initiated the restriction of the Indonesian Seaway, cutting the shallow-water connectivity between the Indian Ocean and the Pacific. Second, Southeast Asia’s vast carbonate platforms, which in places stacked more than two kilometers of limestone, abruptly gave way to deeper-water marine clays near the top of the classic Letter Stage Te, as Borneo became a major source of clastic sediments smothering the shallow shelves around Sundaland. For organisms dependent on sunlit carbonate substrates, the habitat simply vanished.

The study’s conclusions ripple beyond taxonomy. By demonstrating that a foraminiferal genus could cross the Pacific barrier during the Chattian, the work aligns with growing evidence that the Oligocene-Miocene tropical oceans were far more connected than the classic provincial schemes suggested, with eastward currents carrying Indo-Pacific species into the eastern Pacific and Caribbean. It also cautions against building evolutionary lineages purely on morphometric numbers without verifying the shell structures that define genera. Several species assigned to Miogypsinella in the literature, including Miogypsinella bornea, Miogypsinella cyprea, and Miogypsinella elongata, lack the diagnostic features of the genus and probably belong in Miogypsinoides, a correction that will force revisions of regional biostratigraphic schemes from Turkey to Borneo.

For a family of organisms that has quietly anchored Oligocene-Miocene stratigraphy for nearly a century, the message is striking: even the smallest fossils, when re-examined with modern imaging, can rewrite the geography of ancient oceans. The miogypsinids that once flourished from Borneo to Mexico were not relics of isolated worlds but participants in a dynamic, interconnected tropical sea, one whose tectonic reorganization closed the doors they had traveled through and erased the platforms they called home.

Subject of Research: Taxonomic revision and palaeobiogeography of Miocene miogypsinid larger benthic foraminifera

Article Title: Taxonomic reassessment and palaeobiogeographical patterns of some Miogypsinidae species, larger benthic foraminifera

Article References: Bassi, D., Braga, J. C., Kinoshita, S., Pignatti, J., & Iryu, Y. (2026). Taxonomic reassessment and palaeobiogeographical patterns of some Miogypsinidae species, larger benthic foraminifera. Journal of Micropalaeontology, 45(2), 653-677. https://doi.org/10.5194/jm-45-653-2026

Image Credits: AI Generated

DOI: 10.5194/jm-45-653-2026

Keywords: larger benthic foraminifera, Miogypsinidae, Miogypsinella, Miogypsinoides, Chattian, Aquitanian, Indo-Pacific, Indonesian Seaway, paleobiogeography, micro-CT, taxonomy, Oligocene-Miocene

The research team, drawing on the Coral Traits Database, compiled fecundity-related data for 277 coral species across 55 genera. Direct empirical measurements of egg production existed for only ten of those species, so the authors turned to trait-based imputation, using the R package funspace and principal components analysis to estimate missing values for polyp density, eggs per polyp, and colony area. Where empirical values could be checked against imputed ones, the estimates followed the same general trends, although the method tended to overestimate at the very high end of the fecundity spectrum. The authors are candid that the resulting figures are first-order approximations rather than precise predictions, and they stress that the extensive infilling of sparse trait data carries a real danger of overgeneralization.

The analysis was conducted at three hierarchical levels. At the finest scale, fecundity per square centimeter was calculated by multiplying polyp density by the number of eggs per polyp. Colony-level fecundity was then derived by scaling that value to an average-sized colony for each species. Finally, total fecundity across the Indo-Pacific was estimated by combining species-level fecundity with geographic range sizes and mean coral cover data from the Status of Coral Reefs of the World: 2020 report, which put Indo-Pacific coral cover at approximately 189,498 square kilometers. Each step required simplifying assumptions, including that egg production per polyp remains constant as colonies grow and that most species reproduce during a single annual spawning event, an assumption broadly consistent with the broadcast-spawning behavior of the majority of coral species.

The results reveal a remarkable spread in reproductive output. Fecundity per square centimeter ranged from 276 eggs in the genus Stylophora to 24,046 eggs in the mushroom coral Polyphyllia, with a mean of 6,877 eggs per square centimeter. Other members of the family Fungiidae, including Ctenactis and Danafungia, recorded similarly enormous per-area values of more than 23,000 eggs per square centimeter. At the colony level, estimates ranged from about 34,000 eggs per average colony in Stylophora to nearly 3.75 million eggs in Polyphyllia, with a cross-species mean of roughly 1.13 million eggs per colony. These differences among genera were statistically significant at both the per-area and colony scales.

Perhaps the most counterintuitive finding is that per-area fecundity correlates only weakly with total fecundity across the Indo-Pacific, with an R-squared of just 0.217. Genera such as Pachyseris, Isopora and Coeloseris topped the regional rankings, each producing on the order of 4 × 10^16 eggs per square kilometer of reef, even though their per-area fecundity was comparatively modest. The explanation lies in abundance: total reproductive potential is driven as much by how much area a genus occupies as by how many eggs its polyps produce. This decoupling between local and regional scales has important implications, because it suggests that a coral’s contribution to reef recovery cannot be judged from tissue-level measurements alone.

When the authors ranked genera by their share of total reproductive potential, a familiar cast of reef-builders emerged. Acropora alone accounted for 28.6 percent of estimated total fecundity across the Indo-Pacific, or about 9.92 × 10^17 eggs, followed by Porites at 12.2 percent and Montipora at 8.1 percent. Together these three genera contributed nearly half of the region’s reproductive output. At the smaller spatial scales, however, the picture was more diverse: massive and branching growth forms each made up roughly half of total reproductive potential across the three levels, with massive corals dominating per-area and per-colony fecundity while branching corals led at the regional scale, likely reflecting their rapid growth rates, wide distributions and high abundance.

The study also uncovered substantial variation within genera. Among Acropora species, fecundity per square centimeter ranged from 233 eggs in Acropora nana to 2,642 eggs in A. fastigata and A. insignis. Montipora species spanned 468 to 14,170 eggs per square centimeter, while Porites ranged from 661 to 13,713. Such within-genus variation means that genus-level classifications can obscure ecologically meaningful differences among species, and it complicates efforts to predict reef resilience from taxonomy alone. The authors note that reproductive mode adds a further layer of complexity: six of the 277 species in the dataset are brooders that release developed larvae multiple times a year, and the single-spawning-event assumption likely underestimates their contribution, although the effect appears relatively minor given the timing of their larval release.

The implications for conservation are significant. Because total reproductive potential is shaped by abundance and range size as much as by per-colony fecundity, protecting highly fecund species at local scales may not translate into regional benefits. The authors argue that conservation efforts should prioritize fecund species across multiple spatial levels, and that identifying reproductive hotspots could enhance reef resilience in the face of climate change and habitat loss. The work also provides a baseline for modeling population dynamics, forecasting recovery after disturbances such as bleaching, cyclones and crown-of-thorns outbreaks, and designating marine protected areas as larval sources that sustain connectivity across the seascape.

There are sobering caveats. The coral cover data underpinning the regional extrapolation were collected between 1997 and 2006, meaning the estimates describe reproductive potential roughly two decades ago, before the repeated severe marine heatwaves of recent years. Elevated temperatures that cause bleaching have been repeatedly linked to reduced egg production, and ongoing losses of adult colonies directly undercut the reproductive capacity of reefs. The authors caution that even a reproductive output measured in quintillions may not be sufficient to counteract the rapid degradation driven by climate change, which has already produced significant declines in coral recruitment in the Caribbean and on the Great Barrier Reef. Whether the Indo-Pacific’s extraordinary fecundity can keep pace with warming oceans remains one of the defining questions for the future of the world’s reefs.

What the study makes unmistakably clear is that reproduction, long a neglected corner of coral science, deserves a central place in reef research and management. The authors hope their first-order estimates will invigorate the collection of empirical data on egg numbers, egg sizes and colony size-frequency distributions, filling the gaps that currently force researchers to rely on imputation. As bleaching events intensify, knowing which species and regions supply the larvae that rebuild reefs may prove as important as knowing which corals bleach first. The three quintillion eggs of the Indo-Pacific represent both a measure of what these ecosystems can still do and a benchmark against which their decline can be tracked.

Subject of Research: Estimation of coral fecundity and reproductive potential across Indo-Pacific reef species, genera and growth forms

Article Title: Patterns in Coral Fecundity Across the Indo‐Pacific

Article References: Bilodeau, M. M., & Quigley, K. M. (2026). Patterns in Coral Fecundity Across the Indo‐Pacific. Ecology and Evolution, 16(10), Article e74441. https://doi.org/10.1002/ece3.74441

Image Credits: AI Generated

DOI: 10.1002/ece3.74441

Keywords: coral reefs, fecundity, Indo-Pacific, Acropora, spawning, trait imputation, reef resilience, climate change, coral reproduction, biodiversity, conservation, Coral Traits Database

The study’s methodology is what sets it apart from much of the existing literature on the region. Rather than offering a country-by-country descriptive tour, the authors apply a narrative review of government and institutional documents, treaty texts and peer-reviewed publications, and then compare the strategic engagement of twelve major and middle powers alongside four small and island states on a consistent set of variables. This comparative table, the authors argue, allows claims about the regional order to rest on evidence rather than assertion. They also embed a human security and small-state agency perspective within the comparative analysis itself, rather than treating it as an afterthought, and they evaluate how economic exposure translates into chokepoint vulnerability and threats to human security.

The analytical stakes are enormous because of geography. The Indian Ocean links the world’s principal energy producers in the Persian Gulf to the largest consumers in East and South Asia, and it hosts several of the busiest maritime chokepoints on Earth, including the Strait of Hormuz and the sea lanes approaching the Strait of Malacca. According to data cited in the study from the U.S. Energy Information Administration and United Nations trade bodies, disruptions at these narrow passages ripple directly into global inflation and supply chains, as recent disturbances around Hormuz have demonstrated. Whoever secures, or threatens, these arteries holds leverage over the economic life of billions of people, which explains why navies from Washington, Beijing, New Delhi, Paris, London and beyond now patrol waters that were once considered distant from their core interests.

The historical sweep of the paper reminds readers that this attention is not new. From the rise of Islam through 1750, as the economic historian K.N. Chaudhuri documented, the Indian Ocean sustained a vast commercial civilisation of monsoon-driven trade long before European arrival. The age of empire then turned the ocean into a British lake, a dominance examined by scholars such as Ashley Jackson and John Darwin. Alfred Thayer Mahan’s 1890 dictum on the influence of sea power upon history, and K.M. Panikkar’s 1946 warning that Indian history had been shaped by neglect of the sea, framed the strategic anxieties that resurfaced after the Cold War, when superpower rivalry in the region, chronicled as early as the 1970s and 1980s, gave way to today’s multipolar contest.

What has changed is the number and variety of players. The study catalogues an extraordinary range of strategic engagements: the United States’ Indo-Pacific strategy and the AUKUS partnership with Australia and the United Kingdom; China’s Belt and Road Initiative and its so-called string of pearls of ports and facilities, a concept first analysed by Gurpreet Khurana in 2008; India’s maritime security strategy and its expanding web of agreements, from a comprehensive strategic partnership with Australia to coast guard harbour development in the Maldives and a maritime rescue centre with Sri Lanka; France’s self-declared resident power role in the southwest Indian Ocean; Japan’s economic cooperation in the Middle East and Africa; and the growing naval ambitions of middle powers such as Türkiye, which is preparing its first aircraft carrier. Even Russia and Saudi Arabia have sought footholds, from a proposed Red Sea naval base deal to aid diplomacy across the region’s least developed countries.

Against this crowded field, the paper’s central mechanism comes into focus. Infrastructure loans, port construction, coast guard vessels, hydrographic surveys and security assistance all arrive with strategic strings attached, and the states that accept them, small island developing states such as the Maldives, Seychelles, Mauritius and Sri Lanka, gain real capabilities they could not otherwise afford. Yet the same dependence concentrates exposure. When external powers compete, the littoral states become arenas for base negotiations, debt leverage and diplomatic pressure, as the abandoned Chinese-linked project in the United Arab Emirates after American intervention illustrated. The authors’ testable proposition is that this competition does not distribute risk evenly: it accrues precisely where fiscal buffers, maritime domain awareness and regulatory control are thinnest.

The human security dimension sharpens the argument further. The study draws on research into coastal hazard vulnerability in India, post-disaster mobilities in small island developing states, and disaster risk reduction two decades after the Indian Ocean tsunami, to show that maritime insecurity is not only about warships. Non-traditional threats, including piracy, trafficking, illegal fishing, climate-driven displacement and the fragility of undersea communication cables, which Observer Research Foundation analyses have flagged as an underappreciated security domain, bear directly on livelihoods. For island states whose economies and very territories are exposed to rising seas, as adaptation studies from Mauritius demonstrate, the line between strategic competition and human survival is thin indeed.

The paper also engages with contested sovereignty questions that continue to shape the region’s legal geography. The International Court of Justice’s 2019 advisory opinion on the separation of the Chagos Archipelago from Mauritius, and subsequent negotiations over the archipelago’s future, show how decolonisation, base politics and great-power strategy remain entangled. Regional institutions such as the Indian Ocean Rim Association offer a forum for cooperation, but the authors suggest that minilateral groupings and middle-power diplomacy, examined in recent work on the region’s security architecture, are increasingly where the real bargaining happens.

Perhaps the study’s most policy-relevant conclusion is its reframing of stability itself. The authors argue that regional stability depends as much on maritime governance and economic cooperation as on the balance between great powers. In other words, more carrier groups and more basing agreements will not, by themselves, make the Indian Ocean safer. What is needed, on their account, is investment in the governance capacity of littoral states, so that the countries sitting on the world’s most valuable sea lanes are not also the ones least equipped to manage the risks that competition generates. That includes coordinated approaches to chokepoint security, debt transparency in port financing, and human-centred frameworks that treat fishermen, coastal communities and island populations as stakeholders rather than bystanders.

For a region that carries the bulk of intercontinental trade and the energy lifelines of Asia, the message of this analysis is a sobering one. The Indian Ocean’s geopolitical moment has arrived, celebrated in strategy documents from Delhi to Washington to Beijing, but the costs of that moment are being quietly externalised onto its smallest and most vulnerable members. Whether the coming decade produces a governed, cooperative ocean or a fragmented arena of competing spheres will depend, the study suggests, not on who wins the rivalry, but on whether the states that host it are finally given the tools to shape it.

Subject of Research: Geopolitical competition, maritime security and human security in the Indian Ocean region

Article Title: The Indian Ocean at the forefront of contemporary world geopolitics: a conceptual and policy analysis

Article References: Prabhu, S. S., & Mohapatra, N. (2026). The Indian Ocean at the forefront of contemporary world geopolitics: a conceptual and policy analysis. SN Social Sciences, 6(10), Article 487. https://doi.org/10.1007/s43545-026-01771-4

Image Credits: AI Generated

DOI: 10.1007/s43545-026-01771-4

Keywords: Indian Ocean, geopolitics, maritime security, chokepoints, human security, small island states, Indo-Pacific, China-India rivalry, maritime governance, sea lines of communication, Belt and Road Initiative, strategic competition

An international research team led by Chiara Bises of the University of Milano-Bicocca, working with veterinary pathologist Michelle M. Dennis of the University of Tennessee and colleagues, examined diseased fragments of Acropora cf. muricata collected by SCUBA in May 2022 from reefs at depths of 7 to 15 meters in Faafu Atoll. Brown band disease had been recorded in the Maldives since 2012, but its underlying pathology had never been described at the microscopic level. The researchers sampled three colonies showing the classic field presentation: a variably intense brown band paralleling an annular zone of acute tissue loss, marked by bright white but non-eroded skeleton. From each colony they collected biopsies capturing three distinct regions along the disease trajectory: the brown band itself, the tissue loss margin, and the bordering apparently healthy tissue.

Identifying the culprit required both morphology and genetics. Ciliates were gently dislodged from coral fragments using menthol treatment, fixed in ethanol, and subjected to DNA extraction and amplification of the 18S rRNA gene using primers originally developed for brown band investigations on the Great Barrier Reef. The resulting sequences, deposited in GenBank, were assembled into a 1300-base-pair alignment alongside reference sequences of the genus Philaster and appropriate outgroups. Maximum likelihood and Bayesian phylogenetic reconstructions, each strongly supported, placed the Maldivian ciliates in a well-defined clade with Philaster guamense isolates previously recovered from diseased Acropora muricata in Australia. Morphological examination of seventy individuals corroborated the molecular identification: oval to elongated cells averaging roughly 336 micrometers in length, with rows of cilia, a centrally positioned elongated macronucleus, and a colorless to brownish-yellow appearance imparted by ingested coral cells and their endosymbiotic algae.

The histological story that emerged from the six biopsies is one of invasion, consumption, and dormancy unfolding in sequence across the lesion. In the brown band region, the researchers found densely packed aggregations of both vegetative and encysted trophonts, the feeding and resting stages of the ciliate, intermingled with fragments of necrotic, dissociated coral tissue representing the basal body wall, surface body wall, and mesenteries. Necrosis in this zone was severe, affecting more than three-quarters of the tissue in the examined fields. Special stains revealed that the cyst capsules stained strongly with Alcian blue and periodic acid Schiff, consistent with acidic mucopolysaccharides, while failing to react with silver or trichrome stains. In five of six biopsies, other organisms, including fungi, flatworms, and Labyrinthulomycetes, clustered within the band, yet none of these saprophytes invaded host tissues or contacted living polyp structures.

The critical evidence came from the tissue loss margin and the tissue beyond it. At the advancing front, vegetative trophonts predominated, lying in direct contact with both intact coral tissues and fragments of dissociated tissue. Where the coral surface was still intact, ciliates occupied deep skeletal spaces and the gastrovascular cavity, pressing against the basal body wall, surface body wall, or mesenteries. Most strikingly, in the bordering regions that appeared completely healthy under gross examination, occasional vegetative trophonts were found deep within skeletal spaces in contact with the basal body wall, and in one case within the gastrovascular cavity touching the mesenteries. These polyps showed intact architecture, regular cell morphology, no necrosis, no degeneration, and no loss of endosymbionts. In other words, the ciliates were infiltrating tissue that was, by every histological measure, still healthy.

This pattern carries profound implications for the pathogenesis debate. One long-standing hypothesis held that bacteria initiate the injury, damaging coral tissue and opening the door for ciliates to consume the compromised remains. The histology does not support this scenario. Bacteria were not microscopically evident within coral tissues, and the only bacterial structures observed were cell-associated microbial aggregates confined to the healthy surface body wall of a single coral, structures generally regarded as potentially symbiotic rather than pathogenic. No degenerative changes suggestive of microbial injury preceded the ciliate invasion. The findings instead align with a model in which Philaster guamense invades coral tissue from the underlying skeleton, attacking deep tissues directly, a strategy that parallels the calcified-matrix invasion documented in shrimp and sea urchins afflicted by related scuticociliates.

Time-lapse observations of diseased fragments in the laboratory added a behavioral dimension to the pathological picture. Tissue loss proceeded from the base of branches toward their tips at approximately 1.2 millimeters per hour, with ciliates advancing from bare skeleton onto intact tissue and then aggregating and encysting on exposed skeleton once tissue resources were depleted. Encystment, the researchers suggest, is triggered by unfavorable conditions such as nutrient depletion or crowding, and involves cytoplasmic condensation and shrinkage within a protective mucinous capsule. The abundance of empty cysts in the brown band may explain why the band’s pigmentation varies in intensity, appearing lighter when many trophonts have exited or died. This clustering and encystment behavior, the authors note, has not been documented in other scuticociliatoses affecting crustaceans, bivalves, echinoderms, or fish, hinting at a pathogenesis unique to the coral system.

The study also carries practical consequences for how coral diseases are diagnosed and named. Gross visual signs alone are notoriously unreliable, since many coral diseases produce overlapping appearances, and the researchers found that tissue appearing normal to the naked eye can harbor substantial microscopic pathology. They therefore propose a formal case definition for acroporid scuticociliate tissue loss disease, requiring rapidly progressing tissue loss, the presence or absence of a brown-pigmented skeletal deposit, microscopic confirmation of invasive ciliates within the skeleton of otherwise normal polyps, dissociation of coral tissue in contact with histophagous trophonts, and molecular or morphological confirmation of scuticociliate identity. Such definitions, grounded in histology rather than appearance, could bring much-needed consistency to surveillance and research across the Indo-Pacific and beyond.

Caveats remain. The sample size was limited to three colonies and six biopsies, constrained by the low prevalence of active lesions, the remote location, and ethical reluctance to place additional destructive sampling pressure on stressed reefs. Definitive proof of causation will ultimately require experimental infection trials in healthy corals, along with control biopsies from colonies far from any tissue loss. The role of Philaster lucinda, a related species sometimes co-occurring with P. guamense in Great Barrier Reef outbreaks but absent from the Maldivian samples, also remains unresolved. Nevertheless, the consistency of the pathological findings across all biopsies, combined with the absence of any alternative pathogen or pre-existing injury, positions Philaster guamense as a credible primary driver of brown band disease. As coral reefs face intensifying thermal stress and disease outbreaks worldwide, understanding which organisms truly kill corals, and at what stage of degradation they intervene, is essential for designing effective conservation responses. This study provides both a histopathological framework for tracking disease progression and a compelling case that, in brown band disease, the ciliate is not a scavenger but the executioner.

Subject of Research: Histopathology of brown band disease caused by the scuticociliate Philaster guamense in Acropora corals from the Maldives

Article Title: Histopathology of scuticociliate tissue loss associated with Philaster guamense (brown band disease) in Acropora cf. muricata from the Republic of Maldives

Article References: Bises, C., Dennis, M. M., Gobbato, J., Maggioni, D., Galli, P., & Montano, S. (2026). Histopathology of scuticociliate tissue loss associated with Philaster guamense (brown band disease) in Acropora cf. muricata from the Republic of Maldives. Coral Reefs. https://doi.org/10.1007/s00338-026-02954-4

Image Credits: AI Generated

DOI: 10.1007/s00338-026-02954-4

Keywords: brown band disease, Philaster guamense, coral disease, Acropora, histopathology, scuticociliate, Maldives, coral reefs, tissue loss, ciliate pathology, Indo-Pacific, coral health