The leptomedusa Dichotomia cannoides is reported for the first time from the Red Sea, extending its known distribution beyond the western Atlantic and western Pacific Ocean. Five specimens were documented in the northern Gulf of Aqaba, and one was collected for molecular analysis. In situ photography was used to extract diagnostic characters and natural habitus. DNA barcoding of the mitochondrial COI gene showed 98.03% identity with D. cannoides from Florida. Phylogenetic analysis confirmed its placement within D. cannoides, distinct from related leptothecate taxa. This finding increases the number of Leptothecata species recorded in the region to 15. The delayed detection of D. cannoides in the Red Sea may be due to its small size, limited seasonality or a recent introduction via ballast water or hull fouling. The species remains known only from its medusa stage. We further discuss how environmental DNA may help uncover its life cycle and those of other hydrozoans.

Phenotypic plasticity refers to the capacity of an organism’s phenotype to vary in response to changes in environmental conditions, without any change in the individual genotype. Sea urchins (Echinoidea) are well-known for their morphological and behavioural plasticity in response to changing habitats or trophic environments. Phenotypic plasticity has been little studied in directly developing species, in which low levels of phenotypic plasticity are usually expected as a consequence of high levels of genetic differentiation among populations and local genetic adaptation. In the present work, we report a significant plasticity in the direct-developing and brooding sub-Antarctic species Ctenocidaris (Eurocidaris) nutrix (Echinoidea, Cidaridae) through morphological and trophic analyses of gut contents and δ13C and δ15N isotopic compositions. Molecular data (COI mtDNA) confirm that the different phenotypes of C. nutrix, the short-spined C. nutrix nutrix and the long-spined C. nutrix longispina, are a single species restricted to sub-Antarctic waters. As formerly demonstrated in broadcasting echinoid species, morphological plasticity appears to be mainly linked to depth and swell exposure, specimens from exposed and shallow sites showing shorter spines and larger apical systems compared to specimens from sheltered or deep sites. Significant differences in the diet and trophic niche of the different phenotypes suggest that prey type and food diversity may also be a factor promoting distinct phenotypic responses, both in the feeding behaviour and morphology of echinoids.

In January 1852, as searches continued for Sir John Franklin’s missing Arctic expedition, large quantities of preserved (that is, canned) meats supplied to the Royal Navy were found putrid and caused concern that the expedition had received similar meats with fatal consequences. Whilst a Parliamentary enquiry concluded correctly that the expedition had received good-quality meats, it neglected the fact that some 5% of all canned meats were condemned on ships due to damage and corrosion. As the Franklin expedition would be no exception, the study applies recent evidence of the expedition’s victualling schedule to estimate the number of cans condemned by the time at Beechey Island when a decision would be made whether enough remained to sustain the mission. It also estimates the vitamin B1 (thiamine) content of the meat because high temperatures during canning would have degraded or destroyed that vitamin, and vitamin C, both being essential to health. Any reduction in general rations would add to the decline in the quality of the diet. The expedition’s unique circumstances of long entrapment without recourse to hunting to supplement such deficiencies, or to escape, would prove fatal regardless of the good quality of the canned provisions.

This study presents the first sponge biodiversity inventory of Los Picos reef in Veracruz, Mexico. Although the Veracruz Reef System is known for its high sponge diversity, several recently discovered submerged reefs – including Los Picos – had remained biologically uncharacterised until this investigation. Our comprehensive inventory documents 37 species, identified at the species level, all belonging to Demospongiae; 15 of which are new records for the Mexican coast, and 13 for the Gulf of Mexico (GoM). Six species are described as new: Psammocinia alcoladoi sp. nov., distinguished by a dermal surface armoured with sand and spongin filaments, lightly fasciculated primary fibres, and non fasciculated secondary with long conules and slender fiber diameters; Hyatella hyattus sp. nov., distinguished by its soft and lobular habitus, and slender fiber diameters; Zyzzya marinagreenae sp. nov., is an open fistula with acanthostrongyles irregularly spined and both, acanthostrongyles and isochelae, smaller in size; Desmapsamma paulumharenae sp. nov., has an encrusting shape with larger spicules than D. anchorata; Phorbas veracruzanus sp. nov., consists of conule-shaped processes on an embedded layer and morphometric differences on spicules; and Timea citlallitzina sp. nov., stands out by the lumpy tips of the oxyaster type. The whole, highlighted by two genera, Psammocinia and Zyzzya, both reported for the first time in the GoM. Samples were obtained by SCUBA surveys at 10–16 m depth, between August and October 2017.

The United States has long been a global power deeply entangled in regions like Europe and the Middle East, where its foreign policy has been anchored in clear ontological scripts – defender of democracy, bulwark against terrorism, guarantor of order. In contrast, the Arctic has historically lacked this symbolic and strategic integration into US identity. Despite its formal status as an Arctic state since the 1867 purchase of Alaska, the region has remained ontologically peripheral to US strategic imagination. This paper explores the implications of that absence. Through discourse and content analyses of Arctic strategy documents and congressional hearings from 1867 to 2024, I identify four distinct eras of US Arctic engagement and examine how the region’s underdefined identity position has generated scattered and inconsistent policy. The paper argues that this form of ontological ambiguity has given rise to growing anxiety, particularly status anxiety, amid rising Arctic investments by Russia and China. Rather than paralyzing decision-making, however, this anxiety has begun to function as a catalyst, prompting renewed attention to the Arctic’s strategic, environmental, and symbolic relevance.

Deep-sea trawling is concentrated  on assessing fisheries, or in fishing; a combination of long hauls and a large mesh size results in a rather poor collection of soft-bodied invertebrates. In this contribution, we report upon the finding of the French-New Zealand Halipro 2 expedition, along the Norfolk and Loyalty Ridges, especially regarding the proposal of a new genus and description of a new species of polynoid polychaetes, Jimipolyeunoa richeri gen. n., sp. n. Jimipolyeunoa has over 50 body segments, with 21 pairs of elytra; it resembles Parapolyeunoa Barnich, Gambi and Fiege (2012), but they differ because in Jimipolyeunoa the prostomium lacks cephalic peaks (present in Parapolyeunoa), and its neurochaetae are unidentate or finely bidentate (clearly bidentate in Parapolyeunoa). Further, a parasitic copepod was found in one of the specimens, and it is described as Herpyllobius pleurotumoris sp. n., being unique by having the right side of ectosoma with single bulging tumour-like process on posterior third, adjacent to genital swellings.