Sharks of the World

Deep-water sharks are among the most vulnerable deep-water taxa because of their extremely conservative life-history strategies (i.e., late maturation, slow growth, and reproductive rates), yet little is known about their biology and ecology. Thus, this study aimed at investigating the trophic ecology of five deep-water shark species, the birdbeak dogfish (Deania calcea), the arrowhead (D. profundorum), the smooth lanternshark (Etmopterus pusillus), the blackmouth catshark (Galeus melastomus) and the knifetooth dogfish (Scymnodon ringens) sampled onboard a crustacean bottomtrawler off the south-west coast of Portugal. We combined carbon and nitrogen stable isotopes with RNA and DNA (RD) ratios to investigate the main groups of prey assimilated by these species and their nutritional condition, respectively. Stable isotopes revealed overall small interspecific variability in the contribution of different taxonomic groups to sharks' tissues, as well as in the origin of their prey. S. ringens presented higher δ 15 N and δ 13 C values than the other species, suggesting reliance on bathyal cephalopods, crustaceans and teleosts; the remaining species likely assimilated bathy-mesopelagic prey. The RD ratios indicated that most of the individuals had an overall adequate nutritional condition and had recently eaten. This information, combined with the fact that stable isotopes indicate that sharks assimilated prey from the local or nearby food webs (including commercially important shrimps), suggests a potential overlap between this fishing area and their foraging grounds, which requires further attention.

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“…(2012) and Ebert et al . (2021) except for Scymnodon ringens , for which there is no available information to conduct such identification.…”

Section: Methodsmentioning

confidence: 99%

A glimpse into the trophic ecology of deep‐water sharks in an important crustacean fishing ground

Aranha

Teodósio

Baptista

et al. 2023

Journal of Fish Biology

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“…Cirrhigaleus barbifer is originally described from Japanese waters and exhibits records in the coasts of Indonesia, New Caledonia and Western Australia [1,[3][4][5][6][7]. Cirrhigaleus asper is recognized in the Western Indian and Atlantic Oceans, and in the Hawaiian Islands [2,6,[8][9][10][11]. Cirrhigaleus australis is known from the South-western Pacific Ocean, including Australia (except Western Australia) and New Zealand [3,10], and in the Indian Ocean [12].…”

Section: Introductionmentioning

confidence: 99%

Untangling the systematic dilemma behind the roughskin spurdog Cirrhigaleus asper (Merrett, 1973) (Chondrichthyes: Squaliformes), with phylogeny of Squalidae and a key to Cirrhigaleus species

Viana

Soares²

2023

PLoS ONE

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Cirrhigaleus comprises a small genus of rare barbel-bearing dogfish sharks with distributions in limited regions of all oceans. Generic validity and taxonomic status of some species are upon controversies by morphological and molecular evidence that often suggest reallocation of Cirrhigaleus species into the genus Squalus. Particularly, the roughskin spurdog C. asper exhibits intermediary morphological characteristics within Squalidae that requires clarification. In the present study, a phylogenetic approach was undertaken to test the correct generic placement of C. asper using novel and revised morphological characters. We performed maximum parsimony analysis of 51 morphological characters of the internal (e.g., neurocranium, clasper cartilages, pectoral and pelvic girdles) and external anatomy applied to 13 terminal taxa. Cirrhigaleus represents a valid genus and it is supported by eight synapomorphies: high number of monospondylous vertebrae; medial nasal lobe supported by fleshy core and innervated by the buccopharyngeal branch of the facial nerve; neurocranium with greatest width across nasal capsules; one facet and one condyle in the puboischiadic bar for articulating with the basipterygium; two intermediate segments between the basipterygium of the pelvic fin and the axial cartilage of the claspers; five terminal clasper cartilages; and posterior medial process of the puboischiadic bar absent. Cirrhigaleus asper is sister-species to a small clade comprising C. barbifer and C. australis which is supported by one synapomorphy, presence of conspicuous cusplets in the dermal denticles. Cirrhigaleus barbifer, C. asper and C. australis are redescribed herein and the neotype of C. barbifer is designated. A key to Cirrhigaleus species is also given and the inner relationships within Squalus is tentatively discussed.

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“…The Nursehound Scyliorhinus stellaris is an elasmobranch belonging to the Scyliorhinidae family, order Carcharhiniformes, with a medium size (up to 160 cm), appearing as a bycatch in a variety of fishing gears throughout its distribution range and entering the markets [ 1 , 2 , 3 ]. This shark is widespread in the whole Mediterranean, as well as in the coastal waters of the eastern Atlantic Ocean, from Morocco to the North Sea on the Scandinavian coasts [ 4 ]. It inhabits rocky and algal covered bottoms, at a depth range of 2–380 m, and feeds on mollusks, crustaceans, Osteichthyes and other demersal fishes [ 4 ].…”

Section: Introductionmentioning

confidence: 99%

“…This shark is widespread in the whole Mediterranean, as well as in the coastal waters of the eastern Atlantic Ocean, from Morocco to the North Sea on the Scandinavian coasts [ 4 ]. It inhabits rocky and algal covered bottoms, at a depth range of 2–380 m, and feeds on mollusks, crustaceans, Osteichthyes and other demersal fishes [ 4 ].…”

Section: Introductionmentioning

confidence: 99%

“…From a taxonomic point of view, the family Scyliorhinidae is composed of 7 genera and about 50 species [ 4 ]. Within this family, Compagno et al [ 15 ] described the monophyly of the subfamily Scyliorhininae, which includes the genera Cephaloscyllium , Poroderma and Scyliorhinus , in a hypothesis later supported by molecular studies [ 16 , 17 ].…”

Section: Introductionmentioning

confidence: 99%

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The Nursehound Scyliorhinus stellaris Mitochondrial Genome—Phylogeny, Relationships among Scyliorhinidae and Variability in Waters of the Balearic Islands

Catanese

Morey²,

Verger

et al. 2022

IJMS

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The complete mitochondrial DNA sequence of the Nursehound Scyliorhinus stellaris has been determined for the first time and compared with congeneric species. The mitogenome sequence was 16,684 bp in length. The mitogenome is composed of 13 PCGs, 2 rRNAs, 22 transfer RNA genes and non-coding regions. The gene order of the newly sequenced mitogenome is analogous to the organization described in other vertebrate genomes. The typical conservative blocks in the control region were indicated. The phylogenetic analysis revealed a monophyletic origin of the Scyliorhininae subfamily, and within it, two subclades were identified. A significant divergence of Scyliorhinus spp. together with Poroderna patherinum in relation to the group of Cephaloscyllium spp. was observed, except for Scyliorhinus torazame, more related to this last cited clade. A hypothesis of a divergent evolution consequent to a selective pressure in different geographic areas, which lead to a global latitudinal diversity gradient, has been suggested to explain this phylogenetic reconstruction. However, convergent evolution on mitochondrial genes could also involve different species in some areas of the world.

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Sharks of the World

Cited by 124 publications

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A glimpse into the trophic ecology of deep‐water sharks in an important crustacean fishing ground

A glimpse into the trophic ecology of deep‐water sharks in an important crustacean fishing ground

Untangling the systematic dilemma behind the roughskin spurdog Cirrhigaleus asper (Merrett, 1973) (Chondrichthyes: Squaliformes), with phylogeny of Squalidae and a key to Cirrhigaleus species

The Nursehound Scyliorhinus stellaris Mitochondrial Genome—Phylogeny, Relationships among Scyliorhinidae and Variability in Waters of the Balearic Islands

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