We report the first live in situ observations of the iconic goblin shark (Mitsukurina owstoni) on a seamount near Jarvis Island in 2019 and on the slope of the Tonga Trench in 2024. Past observations are restricted to specimens hauled to the surface, resulting in limited knowledge of this species' ecology. These observations extend its known geographic and depth range considerably, and extend the depth range of lamniform sharks by 108 m. To further clarify habitat preferences and assess conservation status, further sampling, particularly with remote video, is required.

A San Blas skate (Dipturus garricki) was incidentally captured at a depth of ~284m in the Guatemalan Caribbean Sea, ca. 11km northeast of El Quetzalito. The immature female with a total length of 742mm and disc width of 610mm had morphological characteristics consistent with Dipturus garricki. This is the first record of this little-known skate in the western Caribbean region. This new record is significant due to the scarcity of records of this species along its distribution in the Western Atlantic (N = 19).

Guitarfish species (genus Acroteriobatus) display restricted distributions in undermanaged regions of intense fishing pressure. The importance of accurate specimen identification is well established, especially in the context of conservation management. However, guitarfishes remain poorly understood, which is exacerbated by taxonomic uncertainty due to morphological similarity. We therefore aimed (1) to identify molecular operational taxonomic units (MOTUs) within Acroteriobatus by analysing sampled specimens as well as publicly available sequence data for the cytochrome c oxidase subunit I (COI) and nicotinamide adenine dehydrogenase subunit 2 (ND2) genes, and (2) to augment and review the representation of these sequences on public databases. A molecular taxonomic approach integrating species delimitation and specimen assignment methods revealed 14 MOTUs. These MOTUs aligned with current species descriptions, displaying no evidence of cryptic diversity. Both genes demonstrated similar interspecific relationships that broadly reflected current distribution ranges, underscoring sub-regional endemism. Moreover, discrepancies in public sequence repositories were identified, attributed to misidentified specimens and the usage of outdated taxonomic nomenclature. Genetic diversity indices were substantially inflated when specimens were grouped based on reported species versus delimited MOTUs, thus overestimating genetic diversity. We highlight the need for extensive, curated DNA reference libraries, including revising earlier sequence entries in light of new taxonomic insights, to enable reliable identification of morphologically conserved species. The molecular resolution illustrated in this study can aid in clarifying taxonomic uncertainties in the genus Acroteriobatus.

The Western Indian Ocean (WIO) is known for its high diversity of chondrichthyans (sharks, rays, and chimaeras). However, intense fishing pressure has led to severe population declines and local extinctions of several species. The Important Shark and Ray Area (ISRA) process is a collaborative, evidence-based approach used to identify critical habitat for chondrichthyans. We analysed ISRAs across the WIO to quantify the diversity of research methods used to identify them, evaluate spatial overlap with designated marine protected areas (MPAs), model the influence of several species- and jurisdiction-specific variables on ISRA delineation, and explore the importance of incorporating unpublished data into the delineation process. In total, 125 ISRAs (covering > 2.8 million km2; ~10% of total regional surface area) were identified within the WIO from surface waters to ~2000 m depth. These ISRAs contain over one-third (n = 104, 39%) of the 270 chondrichthyan species reported from the region, with 76% being threatened with extinction according to the IUCN Red List of Threatened Species. The underlying evidence supporting ISRA identification was primarily drawn from relatively inexpensive research methods, such as visual census (25%) or fish-market/landing site surveys (22.6%), as well as citizen science (9.5%). Incorporating unpublished records substantially increased the frequency of ISRA delineation, leading to expanded taxonomic and geographic coverage. Still, the full dataset was influenced by the same biases as the published record, tending to favour large-bodied, wide-ranging, and shallow-dwelling species. Only 7.1% of ISRAs are within designated MPAs, with just 1.2% in fully protected no-take areas. The highest no-take overlap occurs in the Seychelles and Chagos Archipelago. These findings highlight the shortfalls in spatial protection of chondrichthyan habitats, but also present a strategic opportunity for policy-makers and resource managers to improve current MPA coverage and meet their commitments under international agreements, such as the Global Biodiversity Framework.

AimTo examine the species richness, distribution and macroecological patterns of elasmobranch assemblages across a broad latitudinal gradient in the Eastern Pacific Ocean (EPO).LocationThe study area encompasses the Pacific coast of the American continent, spanning from 65 degrees N to 60 degrees S, and extending from the coastline to approximately 1000 km offshore, encompassing the oceanic archipelagos.TaxonElasmobranchs.MethodsUtilising the established distribution ranges of 190 elasmobranch species (comprising 89 sharks and 101 rays), we assessed the richness and spatial distribution of these species across the EPO. Subsequently, three macroecological patterns were scrutinised: Rapoport's rule, the Mid Domain Effect with its association to Mean Sea Surface Temperature, and the correlation between body size and latitudinal distribution.ResultsThe analysis of species richness along latitudinal gradients unveiled a bimodal pattern, reaching peaks between 30 degrees to 20 degrees N and 10 degrees N to 5 degrees S. A decline in species richness was observed from tropical to polar regions. Contrary to Rapoport's Rule, Stevens' and midpoint methods demonstrated higher geographic range values at lower latitudes, diminishing towards higher latitudes. Additionally, the mid-domain effect model exhibited a robust correlation with the mean sea surface temperature. Exploring the interspecific relationship between body size and extent of occurrence, it was found that 29 out of 190 species are more susceptible to extinction.Main ConclusionMarine elasmobranchs of the EPO defy conventional latitudinal richness patterns and deviate from Rapoport's rule. Furthermore, our findings indicate a robust correlation between observed richness and both sea surface temperature and environmental heterogeneity. The proportion of species vulnerable to human or stochastic impacts potentially leading to extirpation in relation to their geographic range was low across the majority of examined provinces.

The deep ocean is the last natural biodiversity refuge from the reach of human activities. Deepwater sharks and rays are among the most sensitive marine vertebrates to overexploitation. One-third of threatened deepwater sharks are targeted, and half the species targeted for the international liver-oil trade are threatened with extinction. Steep population declines cannot be easily reversed owing to long generation lengths, low recovery potentials, and the near absence of management. Depth and spatial limits to fishing activity could improve conservation when implemented alongside catch regulations, bycatch mitigation, and international trade regulation. Deepwater sharks and rays require immediate trade and fishing regulations to prevent irreversible defaunation and promote recovery of this threatened megafauna group.

Wedgefishes (Rhinidae) are threatened by unsustainable fishing globally, and especially in the Southwest Indian Ocean (SWIO), due to their high-value fins in the shark trade. The whitespotted wedgefish Rhynchobatus djiddensis and the bottlenose wedgefish R. australiae are both classified as Critically Endangered on the IUCN Red List of Threatened Species, yet a lack of species-specific knowledge and taxonomic uncertainty still exists within this genus. Genetic approaches aid in taxonomic classification and identifying distinct populations for targeted conservation. Morphological specimen identification of samples (n = 189) collected across the SWIO was confirmed based on the cytochrome oxidase c subunit I (COI) and/or nicotinamide adenine dehydrogenase subunit 2 (ND2) gene regions. The genetic diversity and population structure within and between species and sampling locations were investigated using a dual marker approach: (1) 2 concatenated mitochondrial gene regions, namely COI and the control region (n = 117), and (2) 9 nuclear microsatellite markers (n = 146). The overall genetic diversity was moderate, with an indication that different evolutionary forces are at play on a mitochondrial versus nuclear level. The 2 species were delineated based on both marker types, and for R. djiddensis, the sampling locations of South Africa and Mozambique were genetically homogeneous. For R. australiae, significant differentiation was found between sampling locations, with Madagascar and Tanzania being genetically the most similar. This information provides critical insights into the distribution range and population structure of the whitespotted wedgefish species complex that can support the sustainable management of wedgefishes.

The shark-like rays (Rhinopristiformes) are among the most threatened species of cartilaginous fishes. The guitarfishes (Rhinobatidae) are one of 5 families in the order, with 62% of species assessed as Vulnerable or higher by the International Union for the Conservation of Nature (IUCN). Species-specific fisheries and conservation efforts have been limited, however, due to unresolved taxonomic issues and poor species descriptions. Presently, there are 3 described species of Rhinobatos from the southwestern Indian Ocean (SWIO): R. austini , R. holcorhynchus , and R. nudidorsalis . These 3 species have been mistaken for one another and are assessed as Data Deficient by the IUCN. Since the descriptions of R. austini and R. nudidorsalis , additional specimens have become available and a rediagnosis of these 3 species is required to clarify their taxonomic status. In the present study, morphometrics from 4 additional congener Indian Ocean species of Rhinobatos assessed by the IUCN were analyzed and serve as comparative material. In addition to a traditional morphological analysis, morphometrics from all 7 species were analyzed using a principal component analysis (PCA) and linear discriminant analysis (LDA). Results show distinct clusters for the SWIO Rhinobatos and indicate the nasal region is effective in differentiating species. R. austini , R. holcorhynchus , and R. nudidorsalis are confirmed as distinct species and are rediagnosed based on new material. These rediagnoses provide taxonomic clarity for SWIO Rhinobatos and will aid in species-specific identification, leading to improvements in conservation and fisheries monitoring and management.

Here, we summarise the extinction risk of the sharks and rays endemic to coastal, shelf, and slope waters of the southwest Indian Ocean and adjacent waters (SWIO+, Namibia to Kenya, including SWIO islands). This region is a hotspot of endemic and evolutionarily distinct sharks and rays. Nearly one-fifth (n = 13 of 70, 18.6%) of endemic sharks and rays are threatened, of these: one is Critically Endangered, five are Endangered, and seven are Vulnerable. A further seven (10.0%) are Near Threatened, 33 (47.1%) are Least Concern, and 17 (24.3%) are Data Deficient. While the primary threat is overfishing, there are the first signs that climate change is contributing to elevated extinction risk through habitat reduction and inshore distributional shifts. By backcasting their status, few endemic species were threatened in 1980, but this changed soon after the emergence of targeted shark and ray fisheries. South Africa has the highest national conservation responsibility, followed by Mozambique and Madagascar. Yet, while fisheries management and enforcement have improved in South Africa over recent decades, substantial improvements are urgently needed elsewhere. To avoid extinction and ensure robust populations of the region’s endemic sharks and rays and maintain ecosystem functionality, there is an urgent need for the strict protection of Critically Endangered and Endangered species and sustainable management of Vulnerable, Near Threatened, and Least Concern species, underpinned by species-level data collection and reduction of incidental catch.

Harriotta avia sp. nov., a new species of long-nose chimaera (Holocephali: Chimaeriformes: Rhinochimaeridae), is described from specimens collected off New Zealand in the Southwest Pacific Ocean. The species is distinguished from its congeners by a combination of the following characters: elongated, narrow and depressed snout up to 56

A new species of shortnose chimaera is described from a single specimen collected at 772-775 m depth in the Andaman Sea (07.54 degrees N; 96.99 degrees E) off Thailand. The species is distinguished from its congeners by the combination of the following characteristics: massive head with short snout; eyes relatively large, horizontally oval, eye length 32.2% head length; thin body with a relatively long trunk 40% body length (BDL), deciduous skin; uniformly dark brown; preopercular and oral lateral line canals sharing a common branch; posterior margin of pectoral fins slightly convex; long dorsal spine 27% BDL, longer than the first dorsal fin. The new species is morphologically close to Chimaera macrospina from Australia but differs in the length of the ventral caudal lobe, snout-vent length, and pectoral fin anterior margin length. It can be distinguished from C. macrospina and other Chimaera species based on the DNA sequence divergence of the mitochondrial ND2 gene.

Warren's sixgill sawshark, Pliotrema warreni , is confirmed for the first time in Namibian waters, from two specimens. One specimen was collected by fisheries observers on a vessel fishing in southern Namibian waters in March 2010. The other was found dead on a beach in central coastal Namibia, in August 2014. The West African catshark, Scyliorhinus cervigoni , is documented for the first time in northern Namibia, from a specimen recorded during surveys of chondrichthyan bycatch on a commercial bottom trawler. This extends the species' range southwards from Angola. Records of bull sharks Carcharhinus leucas are also documented, providing a better understanding of their distribution in Namibia. Several anglers have reported catching bull sharks in the Kunene River (from the riverbank on the Namibian side) and just south of the river mouth, along the Namibian coast.

Until recently, the tentacled butterfly ray, Gymnura tentaculata (Valenciennes in Müller & Henle, 1841 ), had not been seen for over three decades and had been assessed as Critically Endangered–Possibly Extinct on the IUCN Red List of Threatened Species. An elasmobranch-specific monitoring program undertaken between October 2019 and July 2020 allowed the discovery of a population of the species along southern Iranian waters. This allowed for a detailed redescription of the morphology as well as generating molecular data for G. tentaculata based on material retrieved during surveys. Gymnura tentaculata is a small (to 85-cm disc width) gymnurid endemic to the northwestern Indian Ocean that can be distinguished from other Gymnura Kuhl in van Hasselt, 1823 , by a combination of characteristics, including a small tentacle present on the posterior end of each spiracle, a short tail without bands, and a small dorsal fin always present at its base. Historically, the confirmed range of the species comprised coastal waters of Iran, Pakistan, and India, but it now appears limited to Iranian waters of the eastern Persian Gulf and the Gulf of Oman. Threats to this gymnurid across its current geographical range are also discussed.

Technological advances have enabled the expansion of ocean exploration to include the deep ocean, providing new species observations. Here, the authors present two new observations, captured by deep-sea cameras, of the sleeper shark Somniosus cf. pacificus from the Solomon Islands and Palau. This presents the first observation of S. cf. pacificus in the western Pacific tropics and extends its range about 2000 nautical miles south. The observations presented here provide much-needed information on the range of this species which can help guide future management and conservation actions.

In this short communication, we describe the first reported case of an in-situ observation and subsequent sampling of a fossil Otodus megalodon tooth from a deep-sea locality in the Pacific Ocean (14.11332 degrees N, 167.39357 degrees W; 3090 m depth). The additional documentation of its location prior to collection allows for tentative conclusions on surrounding factors leading to its current state, such as sedimentation rate and manganese encrusting.

On September 11, 2022, two megamouth sharks ( Megachasma pelagios ), estimated at 3.7–4.6 m TL, were observed swimming together near the surface about 39 km off the coast of San Diego, CA, USA. Megamouth sharks are rarely observed pelagic sharks, and the film from this encounter provided new insight into the social behavior of this species. We attempt to put the behavior of these two individuals into the context of past sightings, known megamouth shark biology, and with analogous behavior observed in other shark and pelagic fish species.

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The ability to correctly identify specimens at the species level is crucial for assessing and conserving biodiversity. Despite this, species-specific data are lacking for many of South Africa's catsharks due to a high level of morphological stasis. As comprehensive and curated DNA reference libraries are required for the reliable identification of specimens from morphologically similar species, this study reviewed and contributed to the availability of cytochrome c oxidase subunit I (COI) and nicotinamide adenine dehydrogenase subunit 2 (NADH2) sequences for South Africa's catsharks. A molecular taxonomic approach, implementing species delimitation and specimen assignment methods, was used to assess and highlight any taxonomic uncertainties and/or errors in public databases. The investigated species were summarised into 47 molecular operational taxonomic units (MOTUs), with some conflicting specimen assignments. Two Apristurus specimens sampled in this study remained unidentified, revealing the presence of previously undocumented genetic diversity. In contrast, haplotype sharing within Haploblepharus-attributed to nucleotide ambiguities-resulted in the delimitation of three congeners into a single MOTU. This study reveals that molecular taxonomy has the potential to flag undocumented species and/or misidentified specimens, and further highlights the need to implement integrated taxonomic assessments on catsharks that represent an irreplaceable component of biodiversity in the region.