David A. Ebert

Moss Landing Marine Laboratories | MLML · Moss Landing Marine Laboratories

Aim: To examine the species richness, distribution and macroecological patterns of elasmobranch assemblages across a broad latitudinal gradient in the Eastern Pacific Ocean (EPO). Location: The study area encompasses the Pacific coast of the American continent, spanning from 65°N to 60°S, and extending from the coastline to approximately 1000 km of...

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 r...

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% BDL; long, s...

The Japanese velvet dogfish Scymnodon ichiharai Yano and Tanaka 1984 (Somniosidae) is a rare deep-sea shark hitherto known only from the northwest Pacific Ocean. This species is observed for the first time from the northern Indian Ocean. Two male specimens with total length (TL) of 760 mm, and 323 mm were caught by longline hook in the commercial m...

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 S...

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 pop...

A new species of shortnose chimaera is described from a single specimen collected at 772-775 m depth in the Andaman Sea (07.54° N; 96.99° 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...

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 bee...

Global biodiversity continues to decline in the terrestrial and aquatic realms. Across animal groups, threatened species are at risk of extinction if not managed effectively and permitted to recover. The cartilaginous fish order Rhinopristiformes (rhino rays) comprises 5 families: sawfishes, wedgefishes, guitarfishes, giant guitarfishes, and banjo...

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...

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°N, 167.39357°W; 3090 m depth). The additional documentation of its location prior to collection allows for tentative conclusions on surrounding...

Biodiversity loss is a major global challenge and minimizing extinction rates is the goal of several multilateral environmental agreements. Policy decisions require comprehensive, spatially explicit information on species’ distributions and threats. We present an analysis of the conservation status of 14,669 European terrestrial, freshwater and mar...

The occurrence of the Filetail catshark Parmaturus xaniurus is rare in the Gulf of California (GC), and its population structure is unknown. We reported its occurrence as bycatch of the Pacific hake fishery in the northern GC. We examined 22 mature females (412-620 mm total length) caught at 263.0-360.2 m depth.

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 i...

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...

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 atte...

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 allowe...

A new species of sawtail catshark, Galeus friedrichi n. sp., is described from the Philippines. The new species is separable from other western Pacific Galeus species by the absence of saddle or blotch markings, a large size >50 cm TL, 40 monospondylous vertebrae, and 83 precaudal vertebrae. All regional Galeus, other than Galeus sauteri, can be di...

Shark-like rays (order Rhinopristiformes) are the most threatened cartilaginous fish globally. Despite this, unresolved taxonomic issues still exist within the group. To date, no studies have used complete mitochondrial genomes to assess the phylogenetic placement of Acroteriobatus within the non-monophyletic family Rhinobatidae. The current study...

A new genus of skate (Caliraja gen. nov.) is described based on egg case morphology and the number of embryos per egg case. Caliraja gen. nov. egg cases differ from those of the genus Beringraja by a combination of following characteristics: egg cases relatively small in size, lacking ridges, fine striations on the capsule surface, and moderately l...

The Sharpfin Houndshark, Triakis acutipinna, was described in 1968 from a specimen captured from Isla de la Plata, Ecuador. Since then, there have been no confirmed records of the species. To investigate the contemporary occurrence of this ‘lost shark’, a multi-pronged approach was undertaken. This included a literature review, development of an ed...

A new genus of skate (Caliraja gen. nov.) is described based on egg case morphology and the number of embryos per egg case. Caliraja gen. nov. egg cases differ from those of the genus Beringraja by a combination of following characteristics: egg cases relatively small in size, lacking ridges, fine striations on the capsule surface, and moderately l...

The deep-sea fishery for Patagonian toothfish (Dissostichus eleginoides) in Peru offers the opportunity to document species that may be new or rare to the region, or possibly new to science. Here, we report specimens caught, photographed and discarded in a vessel operating in the deep-sea fishery for D. eleginoides, during two fishing trips in 2019...

A new species of softnose skate, Bathyraja chapmani n. sp., is described from two female specimens collected in deepwater off Lima, Peru (-11.933°,-78.15°), in the southeastern Pacific, at 1714 m deep, in a fishery for Patagonian toothfish. The new species is separated from other southeastern Pacific Bathyraja species by having the same color and s...

Centrophorus uyato (Rafinesque, 1810) has a complicated nomenclatural history which has led to multiple scientific names being ascribed to this species. In the Mediterranean Sea, and elsewhere in its range, this species was previously referred to as C. granulosus (Bloch & Schneider, 1801). The first paper in this revision series clarified that C. g...

Softnose skates (Rajiformes: Arhynchobatidae: Bathyraja Ishiyama) are the most diverse skate genus, with 54 species, and are readily distinguishable from other genera in the family by their poorly calcified, flexible rostral cartilages. Six Bathyraja species are considered valid in the eastern North Pacific, including: B. abyssicola, B. aleutica, B...

Nine egg capsules of the Rasptail Skate (Rostroraja velezi) were collected from their southernmost distributional range in northern Peruvian waters for their description. Egg capsules had a glossy black or dark brown color, with a subrectangular shape, slightly wider at posterior end than at anterior end. Egg capsules when observed under a stereosc...

The southwest Indian Ocean (SWIO) is a hotspot of endemic and evolutionarily distinct sharks and rays. We summarise the extinction risk of the sharks and rays endemic to coastal, shelf, and slope waters of the SWIO and adjacent waters (Namibia to Kenya, including SWIO islands). Thirteen of 70 species (19%) are threatened: one is Critically Endanger...

Among the largest fish species, the basking shark (Cetorhinus maximus) is found circumglobally in temperate and tropical waters. Though historical documents have recorded their presence in the California Current Ecosystem (CCE), basking sharks are now only rarely observed in this part of their range. We compiled recent and historical data from syst...

In recent years, the eagle ray family Myliobatidae has undergone major taxonomic revisions due to molecular and morphological findings. A new species of eagle ray, Aetomylaeus wafickii sp. nov., is described based on specimens collected from the Arabian Gulf, Northwest Indian Ocean. The new species externally most closely resembles A. caeruleofasci...

Integrating both morphological and genetic data, we describe Squatina mapama, a new species of the angel shark genus Squatina, found on the upper continental slope off the Caribbean coast of Panama. Distinguishing characters of S. mapama include a wider pectoral and pelvic span; a shorter head length; a narrower mouth; short fringed nasal flaps and...

The recent ocean-warming events along the California coast have extended the northern range of several elasmobranch species. The Banded Guitarfish, Zapteryx exasperata, is a poorly known shallow-water batoid, typically found in warm-temperate to tropical waters of southern California, USA and the Gulf of California, Mexico. During a Baited Remote U...

Somniosus pacificus, Pacific Sleeper Shark

The scale and drivers of marine biodiversity loss are being revealed by the International Union for Conservation of Nature (IUCN) Red List assessment process. We present the first global reassessment of 1,199 species in Class Chondrichthyes—sharks, rays, and chimeras. The first global assessment (in 2014) concluded that one-quarter (24%) of species...

The southwest Indian Ocean (SWIO) is a hotspot of endemic and evolutionarily distinct sharks and rays. We summarise the extinction risk of the sharks and rays endemic to coastal, shelf, and slope waters of the SWIO and adjacent waters (Namibia to Kenya, including SWIO islands). Thirteen of 70 species (19%) are threatened: one is Critically Endanger...

The scale and drivers of marine biodiversity loss are being revealed by the International Union for Conservation of Nature (IUCN) Red List assessment process. We present the first global reassessment of 1,199 species in Class Chondrichthyes—sharks, rays, and chimeras. The first global assessment (in 2014) concluded that one-quarter (24%) of species...

Recent sampling efforts and examinations of museum material provided evidence for a complex of species within Acroteriobatus leucospilus (Norman, 1926). The present manuscript contains a redescription of A. leucospilus involving the syntypes and additional material, as well as formal descriptions of two new species of Acroteriobatus Giltay, 1928. A...

Three species of ghost sharks (Chimaeriformes) were recorded for the first time from the Andaman Sea of Thailand during a deep-sea trawl survey conducted from October 1-15, 2018. Morphological characteristics primarily revealed species described as the sicklefin chimaera, Neoharriotta pinnata (Rhinochimaeridae), longspine chimaera, Chimaera aff. ma...

A new species of catshark, Apristurus manocheriani n. sp., is described from 8 specimens collected from seamounts in the southwest Indian Ocean (SWIO). The new species is placed in the Apristurus spongiceps subgroup and is only the second known species in this subgroup occurring in the western Indian Ocean. Geographically, A. manocheriani is known...

This is the essential illustrated guide for anyone interested in these fascinating fishes. The number of shark species has increased over the past 15 years with over 20% of all known species having been described. In fact, the new Sharks of the World book have about 50 species that have been added since the previous edition, bringing the total numb...

A Pocket Guide to Sharks of the World is the only field guide to identify, illustrate, and described every known shark species. Its compact format makes it handy for many situations, including recognising living species, fishery catches, or parts sold at markets. This expanded second edition presents lavish images, details on newly discovered speci...

Assessment of the conservation status of the Sharpfin Houndshark, Triakis acutipinna

Cosmopolitan marine pelagic species display variable patterns of population connectivity among the world’s major oceans. While this information is crucial for informing management, information is lacking for many ecologically important species, including apex predators. In this study we examine patterns of genetic structure in the broadnose sevengi...

A new species of lanternshark, Etmopterus brosei sp. nov. (Squaliformes: Etmopteridae), is described from the southeastern Atlantic and southwestern Indian oceans. The new species resembles other members of the Etmopterus lucifer Jordan & Snyder, 1902 clade in having linear rows of dermal denticles, and most closely resembles the conspecific E. scu...

Red list assessment of Dasyatis chrysonata

The history of elasmobranch ageing highlights the difficulty of age estimation in animals lacking ossified structures. Ageing techniques are numerous, yet all are limited by difficulties of validation and verification and inherent subjectivity. Sample scarcity further hinders progress as limited samples cannot be risked on exploratory techniques. T...

Chondrichthyan egg cases are important elements for species-specific identification and also provide a valuable aid in determining a species spatial distribution, as well as for defining spawning areas. Considering the absence of a general key for the identification of the egg cases of the Mediterranean Chondrichthyes, this work aims to fill this g...

An annotated checklist of chondrichthyan fishes (sharks, batoids, and chimaeras) occurring in South African waters is presented. The checklist is the result of decades of research and on-going systematic revisions of the regional fauna. The chondrichthyan fauna of South Africa is one of the richest in the world with 191 species, comprising 50 famil...

Sharks and rays are possibly the most threatened Class of marine fishes and their declines can be halted if protected areas are optimised to benefit these species. We identify spatial priorities for all 63 endemic sharks and rays in the marine biodiversity hotspot, the Western Indian Ocean (WIO). Collectively, while the WIO nations currently surpas...

The Critically Endangered shorttail nurse shark Pseudoginglymostoma brevicaudatum (Günther, 1866) is a small-bodied Orectolobiform shark found only in the Western Indian Ocean (WIO). We report here on a significant range extension for P. brevicaudatum based on four records of the species in southern Mozambique, recorded during research surveys, inc...

Ghost sharks (subclass Holocephali) remain a largely data-poor group of cartilaginous fishes. The general paucity of attention may partially be related to identification and unresolved taxonomic issues, occurrence in the deep oceans, and their low value and interest in fisheries (which some notable exceptions). Here, we synthesize and assess the ex...

The waters of the Northeast Atlantic and Mediterranean Sea are home to an amazing variety of sharks, rays, and chimaeras. This ground breaking, comprehensive and easy-to-use field guide covers all 146 species found in the Mediterranean, the waters of the European Atlantic and Iceland, along all the Scandinavian coasts, in the Black Sea and as far s...

Fig. 1 In situ imagery of Hydrolagus melanophasma (1367 m) at Clipperton Atoll (N 10.23993, W − 109.21736). a Adult male approaching camera; b aggregation of males; c adult female with egg cases visible; d female with egg cases co-occur with two males over rock and sand habitat with low relief Communicated by L. Menzel Electronic supplementary mate...

The Southern Lanternshark, Etmopterus granulosus, is a deep-sea shark commonly found throughout the oceans of the southern hemisphere and frequently caught as bycatch in deep-sea fisheries. Despite its common occurrence, little is known about this species’ life history and reproductive biology. Here, we develop species-specific microsatellite marke...