Michael Lee Berumen

Global biodiversity loss demands that research effort be directed towards species most at risk. Yet conservation science is biased by species' accessibility and perceived charisma, raising concerns that threatened species may be overlooked. We apply a structured causal modelling framework to 651 species of rays (superorder Batoidea), a highly threatened yet understudied lineage of cartilaginous fishes, to disentangle the drivers of research effort. We quantify the causal effects of taxonomy, extinction risk, accessibility (range size, depth, economic context, year of description) and charisma (body size, shape, patterning and colouration) on species-level research outputs from more than 7000 publications. Research effort was strongly taxonomically biased, driven by accessibility and charisma, with shallow depth, broad geographic ranges, large body size and distinctive morphologies attracting disproportionate attention. Extinction risk exerted a counterintuitive nonlinear effect: Critically Endangered and Endangered species received significantly fewer publications than Near Threatened and Vulnerable species and were comparable to Data Deficient species. This effect is consistent with a ‘Goldilocks’ zone in which species are threatened enough to justify research but not so threatened that it becomes prohibitively challenging. Systematic research bias away from the species most in need undermines conservation efforts. Realigning research priorities is essential to combating the biodiversity crisis.

The tiger shark is a highly migratory apex predator with distinct populations in the Atlantic and Indo-Pacific regions. Regional analyses in the western Atlantic Ocean have revealed additional genetic differentiation between northern (Caribbean) and southern (Brazilian) populations, particularly in maternally inherited mitochondrial DNA. The eastern Atlantic Ocean, however, remains understudied, leaving connectivity between American and African populations unresolved. Using a fin-mounted satellite transmitter, we document the complete eastward transatlantic movement of a female tiger shark (2.9 m total length), tracked from Fernando de Noronha Archipelago, Brazil, to the coastal waters of Sierra Leone, West Africa. Following an initial prolonged residency of around Fernando de Noronha, the individual undertook a 6,764 km migration across the Atlantic over 116 days (mean ~58 km day ^-1 ). Surfacing behavior differed significantly between the residency and migration phases, shifting from predominantly nocturnal to predominantly diurnal detections. This movement corroborates previous findings that female tiger sharks can disperse across basin scales and suggests that equatorial migration may facilitate genetic connectivity between the western and eastern Atlantic. In the absence of genetic data from West Africa, the demographic and genetic consequences of such movements remain undetermined, underscoring the need to integrate telemetry with expanded population genetic sampling to better understand connectivity in highly mobile marine predators.

Trimma charon sp. nov . is described based on two specimens collected at 30 m depth from the northern Red Sea, Saudi Arabia. The new species can be distinguished from its congeners by the following combination of characters: predorsal midline with scales; fifth pelvic-fin ray unbranched and 41–43% length of the fourth ray; cheek and opercle scaleless; 14 pectoral-fin rays, all unbranched; dorsal fins VI + I,8, with no elongate spines; anal-fin I,8; bony interorbital width 55–62% of pupil diameter; and 6 papillae in row c. In life, T. charon sp. nov . is translucent with a distinct, broad, orange-red midlateral stripe extending from the eye to the caudal-fin base and interrupted by three narrow pale bars, and with conspicuous golden spots on the caudal fin that extend onto the caudal peduncle; the iris is divided into four uneven white/orange sectors. The species is known from two specimens collected at the entrance of a cave on a steep outer-reef slope. Trimma charon sp. nov . was compared with congeners, especially with the very similar T. anaima and co-occurring Red Sea species. An illustrated dichotomous key to all Trimma currently known from the Red Sea is provided. With the description of T. charon sp. nov ., the number of valid species in the Red Sea rises to 11.

Earth's biodiversity is central to ecosystem health and resilience, providing essential functions and services. The Red Sea is a recognised marine biodiversity hotspot with high endemism and unique environmental conditions that support extensive but poorly resolved biodiversity. Here, we applied metagenomic analyses to sediment samples collected from coastal to deep‐sea environments during the Red Sea Decade Expedition 2022 to characterise biodiversity across the web of life. From a single shotgun assay per sample, this approach simultaneously characterised the sediment microbiome, which amplicon‐based surveys recover only through parallel, targeted assays, and extended detection to higher eukaryotes. Using high‐throughput sequencing, we generated 12.8 billion sequences, revealing taxa covering all domains of life. Although eukaryotic sequences represented only 0.7% of the taxonomically annotated dataset, we managed to identify 679 eukaryotic families. Prokaryotic diversity was high, as expected in a basin‐scale sampling coupled with high sequencing depth, with groups covering a wide functional array. Community structure analyses revealed depth‐driven stratification of open‐ocean benthic microbial communities and latitudinal structuring of coastal benthic eukaryotes. Overall, this dataset provides an empirical reliability–coverage trade‐off with direct consequences for the design of eDNA monitoring programmes targeting conservation‐priority taxa, and clear priorities for taxa specific reference‐database expansion.

The deep oceans are warming, but we lack reference systems for observing community restructuring without exploitation confounds. Here, we assess the deep Red Sea as a natural analogue for mesopelagic and upper-bathypelagic climate futures. Below 150 m, Red Sea temperatures stabilise at 21–22°C to the seafloor (3,040 m), conditions the global mesopelagic will not reach until at least 2100–2200. Deep-sea fisheries are effectively absent: over 70 years, catch composition has remained among the most coastally dominated globally (6th percentile). We identify 38 additional species, including conspicuous commercial taxa, potentially present but undocumented. Functional-space truncation relative to the Arabian Seas source pool is concentrated along axes of extreme depth-specialisation, while feeding and life-history diversity are retained. No other warm deep basin combines equivalent thermal extremity, oxygenation, and an unexploited baseline. The deep Red Sea is a globally unique, time-limited system for predicting mesopelagic restructuring under sustained ocean warming.

Antipathidae Ehrenberg, 1834 is the largest family within the order Antipatharia (commonly known as black corals), and includes corals distributed worldwide from shallow to deep waters. With over 124 nominal species, Antipathidae comprises taxa with diverse morphologies, whose taxonomic boundaries, diversity, and distribution remain poorly resolved due to morphological convergence, limited sampling, and discordance between genetic and morphological evidence. Here, we integrated phylogenomic analyses from target-capture of ultraconserved elements (UCEs) and exon loci with detailed morphological analyses for a total of 107 black coral specimens, including 70 collected from the Red Sea between 3 and 623 m water depth, 18 from the Indo-Pacific and Atlantic Oceans between 3 and 26 m water depth, and 19 specimens from museum collections, five of which representing type material. Moreover, previously published UCE data from 77 specimens was included in the analysis. Our results supported the resurrection of the family Stichopathidae Roule, 1905 to accommodate the genera Cirrhipathes de Blainville, 1830 and Stichopathes Brook, 1889, formerly assigned to Antipathidae. We described three new genera, Multilobopathes gen. nov., Papillopathes gen. nov., and Opreskopathes gen. nov., to accommodate species previously assigned to Antipathes Pallas, 1766, including newly discovered taxa from the Red Sea. Antipathes lentipinna is reassigned to Multilobopathes lentipinna (Brook, 1889) comb. nov., Antipathes grandis to Papillopathes grandis (Verrill, 1928) comb. nov., Antipathes caribbeana, Antipathes umbratica, and Antipathes rubusiformis are reassigned to Opreskopathes caribbeana (Opresko, 1996), Opreskopathes umbratica (Opresko, 1996), and Opreskopathes rubusiformis (Warner & Opresko, 2004) comb. nov., respectively. Finally, four new species, Multilobopathes ornatus sp. nov., Multilobopathes intricatus sp. nov., Multilobopathes densispinosus sp. nov., and Stichopathes arenicola sp. nov., are described from the Red Sea. Our results provide the first step towards a comprehensive revision of the diversity and distribution of the order Antipatharia.

Cryptobenthic reef fishes (CRFs) comprise a substantial fraction of coral reef biodiversity, representing up to 50% of fish species on a single reef. Their small body size (<5 cm total length), cryptic behavior, and coloration make them difficult to detect, collect, identify, and quantify, and they are therefore frequently overlooked in reef assessments. These sampling limitations have constrained the development of quantitative links between traits, demographic processes, and ecosystem functions, contributing to their historical exclusion from functional diversity studies. To address this gap, we synthesize existing evidence to propose how CRFs contribute to reef functioning, identifying secondary production and trophic transfer as the primary pathways of influence. We develop a mechanistic framework in which ecosystem roles emerge from demographic and interaction-driven processes, growth, reproduction, turnover, and predation-mediated mortality rather than from traits alone. Within this framework, traits act as modulators of these processes, shaping how biomass is produced, renewed, and transferred to higher trophic levels. Building on this perspective, we organize CRF traits into life history, morphological, behavioral, and habitat association categories that are ecologically relevant for explaining variation in growth, turnover, and predation risk. We also highlight the limitations of applying generic reef fish trait frameworks to cryptobenthic assemblages, identify key gaps in life history and demographic data, and outline priorities for future research. Together, this work provides a transparent, scalable framework for integrating CRFs into functional ecology while emphasizing the need for stronger empirical foundations.

Corallimorphs are opportunistic cnidarians that can compete with reef‐building corals for substrate and thrive in disturbed conditions. Their clonal reproduction often results in a patchy distribution, and they typically occupy a negligible percentage of benthic area on tropical coral reefs. In the Red Sea, the corallimorph Rhodactis rhodostoma has been observed in dense aggregations inhabiting shallow reef flats and nearshore habitats, and is less abundant on reef slopes deeper than 3 m. Here, we describe an unusually deep corallimorph barren on the exposed slope of a remote offshore reef 96 km from the Saudi Arabian coast in the south‐central Red Sea. Based on molecular and morphological characteristics, we tentatively identify the species as R. cf. rhodostoma . Mean percent cover of R. cf. rhodostoma ranged from 25% to 35% from depths of 15–30 m, while it was completely absent at 5 m. Although mean percent cover of R . cf. rhodostoma was less than 50% for all depths surveyed, localized patches resulted in areas consisting of ~90% coverage. Contrary to many reports of corallimorph barrens appearing after a physical disturbance, there are no obvious factors promoting corallimorph dominance on this remote reef. Further surveys are needed to document the total extent of the corallimorph barren and to assess if other reefs in the region are susceptible to similar phenomena.