High-quality reference genomes permit deeper investigation into species' evolution and provide insight into species management and conservation. Next-generation sequencing technologies, such as Oxford Nanopore Technologies, allow researchers to generate high-accuracy long-read genetic data in real-time from anywhere in the world, increasing accessibility to sequence data without exportation of the sample. The lava gull (Leucophaeus fuliginosus), an endemic bird species of the Galápagos archipelago, is the world's rarest gull with an estimated population of 300 to 600 individuals. Little genetic research has been done on this species due to its solitary nature and small population size. Here we present a chromosome-level reference genome assembly of an adult female lava gull, generated using ultra-long reads from the Oxford Nanopore Ultra-Long DNA Sequencing Kit and a PromethION 2 Solo device. Initial sequencing generated 1.78 million reads, consisting of 29.6 gigabases (Gbp), with a mean Q-score of 17.8 at an average 22.5× coverage. Our final assembly has a total length of 1.31 Gbp, with 450 scaffolds, and a scaffold N50 of 85.1 Mbp and contig N50 of 42.8 Mbp. The generation of a high-quality whole genome for the lava gull is an important step for investigation into the species' phylogeography and population genetics.
Acropora is the most diverse and widespread reef-building coral genus in the world. Although known for its critical ecological role in shallow water habitats, its abundance and diversity at upper mesophotic depths have only recently been uncovered. Consequently, little is known about the genetic structuring of mesophotic Acropora populations and their potential ecological and evolutionary relationships with shallow populations. Here, we present the first population genomic evaluation of the depth-generalist coral Acropora aculeus to assess genetic structuring across depths (10 and 40 m) and regions (the Great Barrier Reef (GBR) and the Western Coral Sea (WCS)). We observed strong geographic differentiation between regions, indicating the relative isolation of WCS atolls, with some admixture from WCS into the GBR, but rarely in the opposite direction. Conversely, we observed no geographic or depth-related genetic structuring within regions, although the limited sample sizes prevented evaluation of local allelic patterns over depth. In other words, A. aculeus appears to maintain widespread connectivity within regions, consistent with its broadcast spawning reproductive mode. The lack of depth differentiation requires further assessment to evaluate the potential refuge role of mesophotic populations on isolated reefs, such as in the WCS.
BackgroundLa Réunion Island (Mascarene Archipelago, south-western Indian Ocean) hosts a largely introduced ant fauna, shaped by historical and ongoing human-mediated introductions. Despite previous inventories, the ant fauna of the Island remains incompletely documented and updated faunistic records are needed to refine species checklists and improve knowledge of regional biodiversity. Documenting new occurrences contributes to a better understanding of species distributions, biogeographic patterns and invasion dynamics on oceanic islands, which are particularly vulnerable to biological invasions. New informationFollowing recent fieldwork, we report eight new species for La Réunion Island: Brachymymex australis Forel, 1901; Cardiocondyla obscurior Wheeler, 1929; Monomorium exiguum Forel, 1894; Pheidole parva Mayr, 1865; Solenopsis globularia Smith, 1858; Solenopsis gr. pygmaea, Stigmatomma cf. zwaluwenburgi Williams, 1946; and Strumigenys membranifera Emery, 1869. All are introduced species with varying invasiveness status. This work brings the total number of ants known from La Réunion Island to 62, although the presence and identification of some species cited in literature and databases needs verification. Further collections may uncover additional introduced species in urbanised and anthropogenised habitats and native species specific to La Réunion Island or the Mascarene Islands in natural ecosystems.
Vietnam's diverse tropical habitats remain underexplored for ant biodiversity despite being part of the Indo-Burma biodiversity hotspot. This study presents the first detailed taxonomic revision of the ant genus Nylanderia Emery, 1906 in Vietnam, based on a combined approach using morphological characteristics and phylogenomic data. Using targeted enrichment of ultraconserved elements (UCEs) from 18 specimens and extensive morphological assessment of >200 individuals across all castes, we delimit 11 species from Vietnam. Three species are newly described: Nylanderia camon sp. nov., N. congtroi sp. nov., and N. didactica sp. nov., and one subspecies is elevated to species rank: N. donisthorpei (Forel, 1908) stat. nov. Our analysis reveals 3 new country-level records and clarifies the status of morphologically cryptic species through concordant genomic and morphological signals. All known Vietnamese Nylanderia species are diagnosed, with taxonomic accounts provided for each, including high-resolution montage images of all available castes and distribution maps. A revised illustrated key to the worker caste is also presented. This study highlights the utility of UCE-based phylogenetics for species delimitation within morphologically conservative taxa and contributes to a broader understanding of Nylanderia diversity in the Indomalayan region.
Abstract Linear regressions between total alkalinity (TA) and dissolved inorganic carbon (DIC) are widely used to infer the balance between net ecosystem calcification (NEC) and net ecosystem production (NEP) in coral reefs. Using high‐frequency carbonate chemistry observations from an Australian reef flat and simple numerical models, we show that TA–DIC slopes primarily reflect the temporal co‐variability of NEC and NEP, rather than their time‐integrated metabolic balance. To recover time‐integrated metabolic information, diel reef measurements must be coupled with offshore reference conditions, which anchor changes in TA and DIC to NEC : NEP ratios. We further demonstrate that metabolic balance shifts systematically over the diel cycle and depends on light, indicating that it is inherently dynamic rather than static. Together, our results highlight the need to distinguish metabolic co‐variability from metabolic ratios when interpreting carbonate chemistry data in coral reef and other dynamic aquatic ecosystems.
