Search results

Title: Dietary variability in two common Alaskan skates (Bathyraja interrupta and Raja rhina)
Description: Determining trophic relationships within and among species can provide insight into the structure and function of an ecosystem, and can inform the development of multi-species monitoring and management plans. The goal of this study was to address the need for dietary and trophic information of two common and abundant skates in Prince William Sound (PWS), the Bering skate, Bathyraja interrupta, and longnose skate, Raja rhina. Based on identification and analysis of stomach content data, both species were found to be generalist predators with diets dominated by crustaceans and supplemented with teleosts. The primary source of dietary variability for each species was total length, with spatial variables (i.e., latitude, longitude, and depth) also explaining a large portion of total dietary variability in the Bering skate. However, only a small proportion of the total intraspecific dietary variation was accounted for among the analyzed variables, suggesting substantial individual-based differences in the feeding habits of each species. Trophic level estimates indicated that the Bering skate and longnose skates <100 cm total length (TL) were secondary consumers, whereas longnose skates ≥100 cm TL were more piscivorous, tertiary consumers. Significant interspecific dietary differences were also evident, suggesting trophic separation, likely as a function of skate size. Given their abundance and generalistic feeding behavior, PWS skates can provide a means of monitoring demersal community health; information about their foraging ecology will be valuable in gaining a better understanding of trophodynamics within the PWS food web.
Author: Kemper, Bizzarro, Ebert

Title: Pristiophorus lanae sp. nov., a new sawshark species from the western north Pacific, with comments on the genus Pristiophorus Müller & Henle, 1837 (Chondrichthyes: Pristiophoridae)
Description: A new species of sawshark, Pristiophorus lanae sp. nov., is described from off the Philippine Islands. The new species is the second member of the genus Pristiophorus described from the western North Pacific and can be separated from its closest geographic congener, P. japonicus, by having fewer rostral teeth in front of rostral barbels (17-26 versus 25-32), mouth at corners extending forward to below the rear margin of the eye versus extending below the rear one-third of eye margin, a greater mouth width at 6.9-7.8 times into pre-oral length (versus 5.8-6.9), eye length into head length (15.6-15.9 versus 9.8-13.2), mouth width into head length 9.0-10.0 versus 7.4-8.5 times, head width at nostrils 5.2-6.1 times into pre-orbital length versus 3.9-4.9 times, shorter prebarbel length (from snout tip to barbel) of 50.7-54.5% of preoral length versus 53.6-59.2%, a snout angle of 10.6-13.0° versus 12.4°-14.6°, and lateral trunk denticles with flat crowns that are imbricated versus erect crowns that are not imbricated. The number of monospondylous vertebrae is slightly lower in P. lanae (43-48) versus P. japonicus (51-52). The genus is reviewed, with a revised key to its species presented. © 2013 Magnolia Press., Cited By (since 1996):1, Export Date: 11 February 2014, Source: Scopus
Author: Ebert, Wilms
Date: 2013-01-01T00:00:00Z

Title: First Record of the Dwarf False Catshark, Planonasus parini (Carcharhniformes Pseudotriakis) from Sri Lanka
Description: The dwarf false catshark, Planonasus parini, is a soft, stout to slender bodied poorly known deepwater shark, known previously only from the Socotra Islands, southwestern India, and possibly off the Maldives. Here we report on the first record of the Dwarf False Catshark from Sri Lanka, Southwest Bay of Bengal. The specimen, estimated to be approximately 55 cm in total length, was caught by a local fisherman between 300 m and 600 m depth off Trincomalee Outer Harbour near Norway Inlet (08 29'.136N, 81 14'.783E).
Author: Ebert, De Silva, Goonewardena

Title: Etmopterus alphus n. sp.: a new lanternshark (Squaliformes: Etmopteridae) from the south-western Indian Ocean
Description: Article in Press, A new species of lanternshark, Etmopterus alphus (Squaliformes: Etmopteridae), is described from the south-western Indian Ocean. The new species resembles other members of the ‘Etmopterus lucifer’ clade in having linear rows of dermal denticles and most closely resembles E. molleri from the south-western Pacific. The new species is fairly common along the upper continental slopes off central Mozambique, at depths between 472 and 558 m, and is also found on the southern Madagascar Ridge in 650–792 m depth. It can be distinguished from other members of the E. lucifer clade by a combination of characteristics, including arrangement of flank and caudal markings, dimension of flank markings and shape, size and arrangement of dermal denticles along the body. Molecular analysis further supports the distinction of E. alphus from other members of the E. lucifer clade.
Author: Ebert, Straube, Leslie, Weigmann

Title: An overview on the role of Hexanchiformes in marine ecosystems,
Description: The large size, high trophic level and wide distribution of Hexanchiformes (cow and frilled sharks) should position this order as important apex predators in coastal and deep-water ecosystems. This review synthesizes available information on Hexanchiformes, including information not yet published, with the purpose of evaluating their conservation status and assessing their ecological roles in the dynamics of marine ecosystems. Comprising six species, this group has a wide global distribution, with members occurring from shallow coastal areas to depths of c. 2500 m. The limited information available on their reproductive biology suggests that they could be vulnerable to overexploitation (e.g. small litter sizes for most species and suspected long gestation periods). Most of the fishing pressure exerted on Hexanchiformes is in the form of commercial by-catch or recreational fishing. Comprehensive stock and impact assessments are unavailable for most species in most regions due to limited information on life history and catch and abundance time series. When hexanchiform species have been commercially harvested, however, they have been unable to sustain targeted fisheries for long periods. The potentially high vulnerability to intense fishing pressure warrants a conservative exploitation of this order until thorough quantitative assessments are conducted. At least some species have been shown to be significant apex predators in the systems they inhabit. Should Hexanchiformes be removed from coastal and deep-water systems, the lack of sympatric shark species that share the same resources suggests no other species would be capable of fulfilling their apex predator role in the short term. This has potential ecosystem consequences such as meso-predator release or trophic cascades. This review proposes some hypotheses on the ecology of Hexanchiformes and their role in ecosystem dynamics, highlighting the areas where critical information is required to stimulate research directions. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles., CODEN: JFIBA, , , Fish and Fisheries
Author: Barnett, Braccini, Awruch, Ebert
Date: 2012-01-01T00:00:00Z

Title: A new species of chimaera, Hydrolagus melanophasma sp. nov. (Chondrichthyes: Chimaeriformes: Chimaeridae), from the eastern North Pacific.,
Description: A new species of chimaera, Hydrolagus melanophasma sp. nov. (Chimaeridae), is described from the eastern North Pacific. It is distinct from other eastern Pacific chimaeroids by the following characteristics: a large slightly curved dorsal fin spine extending beyond dorsal fin apex, a long second dorsal fin of uniform height throughout, large pectoral fins extending beyond the pelvic fin insertion when laid flat, trifid claspers forked for approximately one-quarter the total clasper length and a uniform black coloration throughout. The new species is compared to other eastern Pacific members of the genus Hydrolagus including H. alphus, H. colliei, H. macrophthalmus, and H. mccoskeri. Remote Operated Vehicle (ROV) video footage has identified and documented Hydrolagus melanophasma from the Gulf of California. ROV observations suggest that individuals typically occur over soft-bottom habitats or cobble patches with minimal vertical relief. This is in contrast to other eastern Pacific Hydrolagus species that tend to occur in areas of high rocky relief. The known distribution of this new species at present extends from southern California, U.S.A., along the Pacific coast of Baja California, Mexico, and into the Gulf of California. © 2009 Magnolia Press., Cited By (since 1996):6, , , Fish and Fisheries
Author: James, Ebert, Long, Didier
Date: 2009-01-01T00:00:00Z

Title: Introduction to the systematics and biodiversity of sharks, rays, and chimaeras (Chondrichthyes) of Taiwan
Description: All 13 orders of chondrichthyan fishes occur in Taiwanese waters, representing 52 chondrichthyan families (31 shark, 19 batoid, 2 chimaeroid) and 98 genera (64 shark, 31 batoid, 3 chimaeroid). A total of 119 shark, 58 batoid, and 4 chimaera species may occur in the waters surrounding Taiwan, pending taxonomic resolution of some groups. Of the 34 nominally described species from Taiwan, 17 are currently considered valid. The majority of named species occurred during two peak periods in Taiwanese chondrichthyan research; the first between 1959-63, when 13 nominal species were described, of which 7 remain valid today, and a second peak period between 2003-13 when 9 nominal species were described, of which 6 remain valid. The overall species diversity of Taiwan's chondrichthyan fauna is comparable to that of other adjacent marine zoogeographic hotspots, e.g. Japan (126 shark, 75 batoid, 11 chimaeroid species) and the Philippines (81 shark, 46 batoid, 2 chimaeroid species). The Carcharhiniformes, Squaliformes, Myliobatiformes, and Rajiformes are the most dominant orders in terms of abundance and species-richness within this region. Each of these groups may increase in relative diversity with improved taxonomic resolution resulting from the incorporation of molecular tools and renewed morphological studies. Improved identification of Taiwan's chondrichthyan fauna will aid in developing better conservation and management practices. © 2013 Magnolia Press., Export Date: 11 February 2014, Source: Scopus
Author: Ebert, Ho, White, De Carvalho
Date: 2013-01-01T00:00:00Z

Title: Diet, feeding behaviour and habitat utilisation of the blue stingray Dasyatis chrysonota (Smith, 1828) in South African waters,
Description: Analysis of stomach contents for Dasyatis chrysonota revealed that diet varied with size and habitat. The diet of all size classes in the surf zone was comprised primarily of Callianassa spp., Donax spp. and unidentified polychaete species. The medium and large size classes fed primarily on Donax spp., whereas the very large size class fed mainly on Callianassa spp. Polychaetes were of secondary importance as prey for the medium size class. The diet of D. chiysonota in the nearshore zone consisted mainly of Balanoglossus capensis and Callianassa spp. Balanoglossus capensis decreased from an index of relative importance (IRI) of 75.3% for the medium size class to 59.9% for the very large size class, whereas Callianassa spp. increased from 22.8% to 39.4% between the medium and the very large size classes. The offshore zone was the only area in which small size class D. chrysonota were caught. The diet of these small D. chrysonota was primarily polychaetes and amphipods. Polychaetes increased in importance in the medium size class, but declined in each successively larger size class. Conversely, Pterygosquilla armata capensis became the single most important prey item for the very large size class, comprising an IRI of 50.9%. The behaviour pattern used by D. chrysonota to locate and extract prey is described., Cited By (since 1996):27, Fish and Fisheries, CODEN: AJMFA, ,
Author: Ebert, Cowley
Date: 2003-01-01T00:00:00Z

Title: A revision of the western North Pacific swellsharks, genus Cephaloscyllium Gill 1862 (Chondrichthyes: Carcharhiniformes: Scyliorhinidae), including descriptions of two new species.,
Description: The genus Cephaloscyllium Gill 1862 (Chondrichthyes, Carcharhiniformes, Scyliorhinidae) until recently had only two species recognized, C. isabellum [= C. umbratile (Jordan & Fowler 1903)] and C. fasciatum Chan 1966, from the western North Pacific (WNP), with one dubious species, C. formosanum, having been described by Teng in 1962. Recently, three additional species were described, C. circulopullum Yano et al. 2005, C. sarawakensis Yano et al. 2005, and C. parvum Inoue & Nakaya 2006 from this region. Here we present a revision of this genus for the WNP, including redescriptions of C. fasciatum and C. umbratile based on the holotypes, a re-examination of the recently described species, and descriptions of two new species from Taiwan. Cephaloscyllium umbratile can be distinguished from its congeners based on maximum size, length of first dorsal-fin base, anal-caudal space, and dorsal-caudal space. We conclude, based on a comparison of C. parvum and C. sarawakensis, that the former is a junior synonym of the latter species. The two new Taiwanese species can be separated from other WNP species by color pattern, shape of the anterior nasal flap, anal and dorsal-fin size, internarial width, and mouth size. Finally, we present a revised dichotomous key to the WNP Cephaloscyllium recognizing six contemporary taxa: C. circulopullum, C. fasciatum, C. sarawakensis, C. umbratile, C. pardelotum sp. nov. and C. maculatum sp. nov. Copyright © 2008 Magnolia Press., Cited By (since 1996):2, , , Fish and Fisheries
Author: Schaaf-Da Silva, Ebert
Date: 2008-01-01T00:00:00Z

Title: Chlamydoselachus africana, a new species of frilled shark from southern Africa (Chondrichthyes, Hexanchiformes, Chlamydoselachidae),
Description: Frilled sharks (Chondrichthyes, Hexanchiformes, Chlamydoselachidae), long believed to be a monotypic family and genus, consisting of a single wide ranging species, Chlamydoselachus anguineus (Garman, 1884), is now known to contain at least two species. A new species of frilled shark, Chlamydoselachus africana, sp. nov., is described from five specimens collected from southern Africa. The new species, although difficult to distinguish externally from the well known C. anguineus, differ internally by the structural differences in the chondrocranium, lower total vertebral and spiral valve counts, and pectoral-fin radial counts. The new species, Chlamydoselachus africana, is known from off southern Angola, Namibia, and South Africa. © 2009 · Magnolia Press., Cited By (since 1996):3, Fish and Fisheries, ,
Author: Ebert, Compagno
Date: 2009-01-01T00:00:00Z

Title: Biodiversity, Life History, and Conservation of Northeastern Pacific Chondrichthyans
Description: The sharks, batoids, and chimaeras, collectively the class Chondrichthyes, are one of the most successful groups of fishes, with over 1250 species globally. Recent taxonomic revisions have increased their diversity by about 20% over the past 17 years (2000–2016). The Northeast Pacific Ocean is one of the top 20 most diverse regions/countries on the globe with 77 chondrichthyan species, a number less than a quarter that of the most species-rich area (Australia) but that has increased by 10% since 2000 to include three new species (two skates and a chimaera). In this chapter we discuss the species richness of chondrichthyans occurring in the Northeast Pacific Ocean, characterize their life histories, briefly review several fisheries, and summarize the conservation status of those chondrichthyans occurring in the region. Detailed descriptions and evaluations of fisheries can be found in Chapter 7 of AMB Volume 78.
Author: Ebert, Bigman, Lawson

Title: Reproductive biology of catsharks (Chondrichthyes: Scyliorhinidae) off the west coast of southern Africa,
Description: This study presents information on the reproductive biology of five southern African catshark species: Apristurus microps, A. saldanha, Apristurus sp., Galeus polli, and Scyliorhinus capensis. They were caught between Walvis Bay, Namibia, and Cape Agulhas, South Africa, from 50 to 1016 m deep. The reproductive mode of four species was oviparous, whereas G. polli exhibited aplacental viviparity. Males of all species attained first maturity slightly larger than females, and males of the four oviparous species attained a larger LTmax than females. The length at 50% maturity was similar for males and females in most species. All species matured at an LT > 75% of LTmax except for male Apristurus spp. and female G. polli, which matured at 71.2% and 68.8%, respectively, of LTmax. The egg case of A. microps has minute tendrils, whereas those of S. capensis were quite long, suggesting different egg-laying habitats. Fecundity in G. polli ranged from 5 to 13, and litter size increased in relation to increased female length. Embryos of G. polli were large, each measuring approximately 30% of female LT. Neonates of G. polli were common and appear to have a demersal lifestyle; those of the four oviparous species were entirely absent from the study. Gravid A. microps were found in summer and winter, indicating a protracted breeding cycle, but reproductively active S. capensis were caught only in winter. Prior to this study, reproductive information on these catsharks was largely lacking. © 2006 International Council for the Exploration of the Sea., Cited By (since 1996):23, CODEN: ICESE, ,
Author: Ebert, Compagno, Cowley
Date: 2006-01-01T00:00:00Z

Title: Chimaera notafricana sp. nov. (Chondrichthyes: Chimaeriformes: Chimaeridae), a new species of chimaera from southern Africa,
Description: A new species of chimaera, Chimaera notafricana sp. nov., is described from specimens collected off the west and south coasts of southern Africa. The new species is distinguished from its closest congener, the eastern North Atlantic Chimaera monstrosa, by a combination of morphometric characters and coloration: pectoral fin when depressed reaches to origin of pelvic fin base; caudal fin ventral margin terminating slightly posterior to caudal fin dorsal margin insertion; distance from anterior base of dorsal-fin spine to center of supratemporal canal short (6.5-14.8% HDL); pelvic claspers externally trifid and short (12.1-12.3% BDL), divided for distal one-third of length, not extending past distal tip of pelvic fins; uniform blackish brown with dark bluish streaking, precaudal tail with longitudinal light and dark stripes. This new species has a restricted distribution from Lüderitz, Namibia to south of Algoa Bay, Eastern Cape Province, South Africa. Copyright © 2010 Magnolia Press., Fish and Fisheries, ,
Author: Kemper, Ebert, Compagno, Didier
Date: 2010-01-01T00:00:00Z

Title: Resurrection and redescription of Squalus suckleyi (Girard, 1854) from the North Pacific, with comments on the Squalus acanthias subgroup (Squaliformes: Squalidae),
Description: A taxonomie re-evaluation of the status of the North Pacific Squalus suckleyi (Girard, 1854) combining the use of meristie, morphological and molecular data reveal this species to be clearly distinct from the widespread Squalus acanthias (Linneaus, 1758). Differences in the external morphology between S. acanthias and S. suckleyi are subtle and are likely to be masked by intraspecific variation within individuals. However, we found S. suckleyi to differ from S.acanthias based on the following morphological and meristic characteristics: a short, broadly-rounded to acute snout;first dorsal-fin midpoint more posterior to pectoral-fin insertion; pelvic-fin origin closer to second dorsal fin than first dorsal fin; total vertebral counts average 99 (97-106). Molecular analysis of approximately 650 bp of the CO1 mitochondrial gene (DNA barcode region) showed separation of S. suckleyi and S. acanthias into two distinct genetic clades with 98% bootstrap support. Within species genetic diversities were 0.109±0.036% and 0.176±0.041% for S.suckleyi and S. acanthias respectively; between species diversity was 5- 6 fold greater at 0.765+0.307%. Squalussuckleyi is thus resurrected and a neotype for this endemic North Pacific Squalus species is designated. Copyright © 2010 Magnolia Press., Cited By (since 1996):20, ,
Author: Ebert, White, Goldman, Compagno, Daly-Engel, Ward
Date: 2010-01-01T00:00:00Z

Title: Life history of the sevengill shark, Notorynchus cepedianus Peron, in two northern California bays.
Description: Abstract not available (old pdf)
Author: Ebert

Title: Confirmation of the cookiecutter shark, Isistius brasiliensis, from the eastern North Pacific Ocean (Squaliformes Dalatiidae)
Description: The cookiecutter shark, Isistius brasiliensis, is confirmed for the first time from the eastern North Pacific Ocean. The shark, a female 432 mm in total length, was caught in a sablefish pot at a depth of 1132 m off San Nicolas Island, California, USA (32°59′05″N 120°25′99″W).
Author: Ebert, Pien, Kamikawa

Title: Lost and found: Recovery of the holotype of the ocellated angelshark, Squatina tergocellatoides Chen, 1963 (Squatinidae), with comments on western Pacific squatinids
Description: The ocellated angelshark, Squatina tergocellatoides, Chen, 1963 is redescribed from the holotype, which was thought to be lost. Its recent recovery has allowed for a revised description, including new data, and comparison to other Western Pacific squatinids. Squatina tergocellatoides can be distinguished from its congeners by three pairs of prominent large black spots, each with a diameter greater than eye length; two on each pectoral fin at anterior and posterior angles and one on each side near the tail base; another three pairs of lesser defined spots, one large spot on base of each dorsal fin and one located laterally on each side of tail located below first dorsal fin. Ventral surface is uniformly white to cream coloured, and margins of pectoral fins and tail similar in colour to dorsal side. Pectoral fins with angular lateral apices and rounded posterior lobe, pelvic fin tips not reaching origin of first dorsal fin, strongly fringed nasal barbels, small inter-orbital space, head and mouth lengths, broad internarial width and pelvic fin base, a very small pelvic girdle width, and a caudal fin with triangular ventral lobe greater in length than dorsal lobe. Comments on additional specimens are provided, as well as observations on biogeography. A review of western Pacific squatinids is also provided. © 2013 Magnolia Press., Cited By (since 1996):1, Export Date: 11 February 2014
Author: Theiss, Ebert
Date: 2013-01-01T00:00:00Z

Title: The evolution of chondrichthyan research through a metadata analysis of dedicated international conferences between 1991 and 2014
Description: Science is continually evolving, with recent developments in some fields, such as conservation biology, leading to shifts in priorities and needs. Recent international conferences focused on chondrichthyan research provide an opportunity to assess how the research environment of chondrichthyan science has evolved through time. We compiled metadata from Sharks Down Under (1991) and the two Sharks International conferences (2010 and 2014), spanning 23 years. Analysis of the data highlighted taxonomic biases towards charismatic species, a declining number of studies in fundamental science such as those related to taxonomy and basic life history, and the emergence of new research fields or tools such as social science and stable isotope analysis. Although there are limitations associated with our study, which are discussed, it lays the foundation for continued assessment of the progression of chondrichthyan research as future chondrichthyan‑focused international conferences are organised. Considering the research biases that our metadata analysis identifies, we suggest that: (i) greater attention should be given to species or species groups that are of particular conservation concern but that may not necessarily be charismatic (e.g. batoids); (ii) increased support should be given to scientists from low‑income countries; (iii) new research areas should continue to be developed and included within broad integrated research programmes; and (iv) concurrent with this, foundational research should not be neglected. © 2015 NISC (Pty) Ltd., Cited By :2, Export Date: 4 September 2015
Author: Huveneers, Ebert, Dudley
Date: 2015-01-01T00:00:00Z

Title: Morphological characters of the thickbody skate Amblyraja frerichsi (Krefft 1968) (Rajiformes: Rajidae), with notes on its biology
Description: Detailed descriptions of morphological features, morphometrics, neurocranium anatomy, clasper structure and egg case descriptions are provided for the thickbody skate Amblyraja frerichsi; a rare, deep-water species from Chile, Argentina and Falkland Islands. The species diagnosis is complemented from new observations and aspects such as colour, size and distribution are described. Geographic and bathymetric distributional ranges are discussed as relevant features of this taxońs biology. Additionally, the conservation status is assessed including bycatch records from Chilean fisheries. © 2012 Bustamante et al., Art. No.: e39963, Downloaded from: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0039963 (12 June 2014).
Author: Bustamante, Lamilla, Concha, Ebert, Bennett
Date: 2012-01-01T00:00:00Z

Title: Reproduction and embryonic development of the blue stingray, Dasyatis chrysonota, in southern African waters,
Description: Dasyatis chrysonota is perhaps the most common of the 14 whiptail stingray (Chondrichthyes: Dasyatidae) species known to frequent the temperate coastal waters of southern Africa and like other stingrays they possess life history characteristics that make them vulnerable to over-exploitation. First and 50% maturity (Dw50) were determined for 153 males and 204 females from the Eastern Cape Province of South Africa. Disc width (Dw) for first and Dw50 maturity was estimated at 392mm and 395mm Dw, respectively for males and at 500mm and 505mm Dw, respectively for females. The reproductive cycle of males, based on gonadosomatic (GSI) and hepatosomoatic (HSI) indices indicates that they are most active during the spring. Females appear to have an annual reproductive cycle with a maximum HSI occurring during the summer and autumn, but it declines steadily through the birthing season reaching a low in the late spring. Fecundity, following a nine month gestation period, averages 2.8 with a range of 17. Embryos at six different development stages are described. Dasyatis chrysonota, like other dasyatids, exhibit life history characteristics that make them vulnerable to overexploitation, therefore a precautionary management strategy is advised for this species. © 2009 Marine Biological Association of the United Kingdom., Cited By (since 1996):4, CODEN: JMBAA, ,
Author: Ebert, Cowley
Date: 2009-01-01T00:00:00Z

Title: First southeastern Atlantic record of the false catshark, Pseudotriakis microdon (Carcharhiniformes: Pseudotriakidae)
Description: The false catshark, Pseudotriakis microdon, is a large-bodied, poorly known deepwater shark, with a global distribution, except for the eastern Pacific and South Atlantic oceans. Here we report the first record of the false catshark from the southeastern Atlantic. The specimen, estimated to be approximately 290 cm in total length, was observed via an unmanned submersible 700 m depth off the western slope of Valdivia Seamount (26.2° S, 6.3° E).
Author: Clerkin, Ebert

Title: Revision of the genus Centrophorus (Squaliformes: Centrophoridae): Part 1-redescription of Centrophorus granulosus (Bloch & Schneider), a senior synonym of C. acus Garman and C. niaukang Teng,
Description: The genus Centrophorus is one of the most taxonomically complex and confusing elasmobranch groups. A revision of this group is currently underway and this first paper sets an important foundation in this process by redescribing the type species of the genus-Centrophorus granulosus. This taxon name has been previously applied to two different morphotypes: a large species 1.5 m TL and a smaller species ∼1 m TL. Centrophorus acus and C. niaukang are the most commonly used names applied to the larger morphotype. The original description of C. granulosus was based on a large specimen of ∼1.5 m TL, but subsequent redescriptions were based on either of the large or small morphotypes. Centrophorus granulosus is herein redescribed as a large species and a neotype is designated. Centrophorus acus and C. niaukang are found to be junior synonyms of C. granulosus. Centrophorus granulosus is distinguishable from its congeners by its large size, dermal denticle shape, colouration and a number of morphological and biological characteristics. Ontogenetic changes in morphology, dentition and denticle shape for this species are described in detail. © 2013 Magnolia Press., Cited By (since 1996):3, Export Date: 11 February 2014, Source: Scopus, ,
Author: White, Ebert, Naylor, Ho, Clerkin, Veríssimo, Cotton
Date: 2013-01-01T00:00:00Z

Title: Preliminary observations of population genetics and relatedness of the broadnose sevengill shark, Notorynchus cepedianus, in two northeast Pacific estuaries
Description: The broadnose sevengill shark, Notorynchus cepedianus, a common coastal species in the eastern North Pacific, was sampled during routine capture and tagging operations conducted from 2005-2012. One hundred and thirty three biopsy samples were taken during these research operations in Willapa Bay, Washington and in San Francisco Bay, California. Genotypic data from seven polymorphic microsatellites (derived from the related sixgill shark, Hexanchus griseus) were used to describe N. cepedianus genetic diversity, population structure and relatedness. Diversity within N. cepedianus was found to be low to moderate with an average observed heterozygosity of 0.41, expected heterozygosity of 0.53, and an average of 5.1 alleles per microsatellite locus. There was no evidence of a recent population bottleneck based on genetic data. Analyses of genetic differences between the two sampled estuaries suggest two distinct populations with some genetic mixing of sharks sampled during 2005-2006. Relatedness within sampled populations was high, with percent relatedness among sharks caught in the same area indicating 42.30% first-order relative relationships (full or half siblings). Estuary-specific familial relationships suggest that management of N. cepedianus on the U.S. West Coast should incorporate stock-specific management goals to conserve this ecologically important predator. © 2015 Larson et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited., Export Date: 24 July 2015
Author: Larson, Farrer, Lowry, Ebert
Date: 2015-01-01T00:00:00Z

Title: Redescription of hexanchus nakamurai teng 1962, (Chondrichthyes: Hexanchiformes: Hexanchidae), with designation of a neotype,
Description: Hexanchus nakamurai Teng, 1962 is one of two valid nominal species in the genus Hexanchus; the other being H. griseus. The taxonomic history of H. nakamurai is somewhat convoluted due to questions about the validity of whether it constituted a publication or an unpublished dissertation. The issue appeared to have been resolved once it was determined that the Teng's original description met the criteria under the International Commission on Zoological Nomenclature code (Article 8a) of a publication. However, recent molecular studies have indicated that the western North Atlantic H. nakamurai (=?H. vitulus) may be distinct from western Indian Ocean H. nakamurai. Compounding the issue is the loss of the holotype of H. nakamurai from Taiwan. A neotype is herein designated and the species redescribed based on the neotype and eight additional Taiwanese specimens. © 2013 Magnolia Press., Cited By (since 1996):1, Export Date: 11 February 2014, Source: Scopus, ,
Author: Ebert, White, Ho
Date: 2013-01-01T00:00:00Z

Title: Standardized diet compositions and trophic levels of skates (Chondrichthyes: Rajiformes: Rajoidei),
Description: Skates by virtue of their abundance and widespread occurrence appear to play an influential role in the food webs of demersal marine communities. However, few quantitative dietary studies have been conducted on this elasmobranch group. Therefore, to better understand the ecological role of skates, standardized diet compositions and trophic level (TL) values were calculated from quantitative studies, and compared within and among skate and shark taxa. Prey items were grouped into 11 general categories to facilitate standardized diet composition and TL calculations. Trophic level values were calculated for 60 skate species with TL estimates ranging from 3.48 to 4.22 (mean TL = 3.80 ± 0.02 SE). Standardized diet composition results revealed that decapods and fishes were the main prey taxa of most skate species followed by amphipods and polychaetes. Correspondingly, cluster analysis of diet composition data revealed four major trophic guilds, each dominated by one of these prey groups. Fish and decapod guilds were dominant comprising 39 of 48 species analyzed. Analysis of skate families revealed that the Arhynchobatidae and Rajidae had similar TL values of 3.86 and 3.79 (t-test, P = 0.27), respectively. The Anacanthobatidae were represented by a single species, Cruriraja parcomaculata, with a TL of 3.53. Statistical comparison of TL values calculated for five genera (Bathyraja, Leucoraja, Raja, Rajella, Rhinoraja) revealed a significant difference between Bathyraja and Rajella (t-test, P = 0.03). A positive correlation was observed between TL and total length (L T) with larger skates (e.g. >100 cm L T) tending to have a higher calculated TL value (>3.9). Skates were found to occupy TLs similar to those of several co-occurring demersal shark families including the Scyliorhinidae, Squatinidae, and Triakidae. Results from this study support recent assertions that skates utilize similar resources to those of other upper trophic-level marine predators, e.g. seabirds, marine mammals, and sharks. These preliminary findings will hopefully encourage future research into the trophic relationships and ecological impact of these interesting and important demersal predators. © 2007 Springer Science+Business Media, Inc., Cited By (since 1996):38, Fish and Fisheries, CODEN: EBFID, ,
Author: Ebert, Bizzarro
Date: 2007-01-01T00:00:00Z

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