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https://www.readbyqxmd.com/read/29316367/development-of-the-lunate-shaped-caudal-fin-in-white-shark-embryos
#1
Taketeru Tomita, Minoru Toda, Kei Miyamoto, Shin-Ichiro Oka, Keiichi Ueda, Keiichi Sato
The lunate-shaped caudal fin in lamnid sharks is a morphological specialization for their thunniform mode of locomotion, but its developmental process during gestation has been poorly investigated. Observations of 21 embryonic specimens of the white shark (Carcharodon carcharias) revealed that their caudal fin morphology drastically changes from strongly heterocercal to lunate-shaped through ontogeny. This morphological change involves 1) rapid elongation of the ventral lobe, 2) increased upward curvature of the vertebra within the caudal fin, and 3) formation of keels at both lateral sides of the caudal fin base...
January 6, 2018: Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology
https://www.readbyqxmd.com/read/29230354/ecomorphological-inferences-in-early-vertebrates-reconstructing-dunkleosteus-terrelli-arthrodira-placodermi-caudal-fin-from-palaeoecological-data
#2
Humberto G Ferrón, Carlos Martínez-Pérez, Héctor Botella
Our knowledge about the body morphology of many extinct early vertebrates is very limited, especially in regard to their post-thoracic region. The prompt disarticulation of the dermo-skeletal elements due to taphonomic processes and the lack of a well-ossified endoskeleton in a large number of groups hinder the preservation of complete specimens. Previous reconstructions of most early vertebrates known from partial remains have been wholly based on phylogenetically closely related taxa. However, body design of fishes is determined, to a large extent, by their swimming mode and feeding niche, making it possible to recognise different morphological traits that have evolved several times in non-closely related groups with similar lifestyles...
2017: PeerJ
https://www.readbyqxmd.com/read/29214009/the-role-of-hoxa11-and-hoxa13-in-the-evolution-of-novel-fin-morphologies-in-a-representative-batoid-leucoraja-erinacea
#3
Shannon N Barry, Karen D Crow
Background: Batoids exhibit unique body plans with derived fin morphologies, such as the anteriorly expanded pectoral fins that fuse to the head, or distally extended anterior pelvic fin lobes used for a modified swimming technique utilized by skates (Rajidae). The little skate (Leucoraja erinacea), exhibits both of these unique fin morphologies. These fin modifications are not present in a typical shark body plan, and little is known regarding the mechanisms underlying their development...
2017: EvoDevo
https://www.readbyqxmd.com/read/29209245/identification-and-description-of-novel-mood-profile-clusters
#4
Renée L Parsons-Smith, Peter C Terry, M Anthony Machin
Mood profiling has been a popular assessment strategy since the 1970s, although little evidence exists of distinct mood profiles beyond the realm of sport and exercise. In the present study, we investigated clusters of mood profiles derived from the six subscales of the Brunel Mood Scale using the In The Mood website. Mood responses in three samples (n = 2,364, n = 2,303, n = 1,865) were analyzed using agglomerative, hierarchical cluster analysis, which distinguished six distinct and theoretically meaningful profiles...
2017: Frontiers in Psychology
https://www.readbyqxmd.com/read/29077226/species-composition-of-the-international-shark-fin-trade-assessed-through-a-retail-market-survey-in-hong-kong
#5
Andrew T Fields, Gunter A Fischer, Stanley K H Shea, Huarong Zhang, Debra L Abercrombie, Kevin A Feldheim, Elizabeth A Babcock, Demian D Chapman
The shark fin trade is a major driver of shark exploitation in fisheries all over the world, most of which are not managed on a species-specific basis. Species-specific trade information highlights taxa of particular concern and can be used to assess the efficacy of management measures and anticipate emerging threats. The species composition of the Hong Kong Special Administrative Region of China, one of the world's largest fin trading hubs, was partially assessed in 1999-2001. We randomly selected and genetically identified fin trimmings (n = 4,800), produced during fin processing, from the retail market of Hong Kong in 2014-2015 to assess contemporary species composition of the fin trade...
October 27, 2017: Conservation Biology: the Journal of the Society for Conservation Biology
https://www.readbyqxmd.com/read/29056141/the-economy-of-shark-conservation-in-the-northeast-pacific-the-role-of-ecotourism-and-citizen-science
#6
Peter A Mieras, Chris Harvey-Clark, Michael Bear, Gina Hodgin, Boone Hodgin
Historically sharks have been seen either as a source of income through harvesting, or as a nuisance and danger. The economic value of sharks has traditionally been measured as the total value of sharks caught for liver oil, fins, or meat for consumption. Sharks have also been killed to near extinction in cases where they were seen as a threat to fisheries on other species. This is illustrated by the mass extermination of Basking Sharks (Cetorhinus maximus) in British Columbia. They were seen as a nuisance to fishermen as they got entangled in gill nets during the salmon fishing season...
2017: Advances in Marine Biology
https://www.readbyqxmd.com/read/29020095/a-multiplex-pcr-mini-barcode-assay-to-identify-processed-shark-products-in-the-global-trade
#7
Diego Cardeñosa, Andrew Fields, Debra Abercrombie, Kevin Feldheim, Stanley K H Shea, Demian D Chapman
Protecting sharks from overexploitation has become global priority after widespread population declines have occurred. Tracking catches and trade on a species-specific basis has proven challenging, in part due to difficulties in identifying processed shark products such as fins, meat, and liver oil. This has hindered efforts to implement regulations aimed at promoting sustainable use of commercially important species and protection of imperiled species. Genetic approaches to identify shark products exist but are typically based on sequencing or amplifying large DNA regions and may fail to work on heavily processed products in which DNA is degraded...
2017: PloS One
https://www.readbyqxmd.com/read/28931746/voltage-gated-sodium-channel-gene-repertoire-of-lampreys-gene-duplications-tissue-specific-expression-and-discovery-of-a-long-lost-gene
#8
Harold H Zakon, Weiming Li, Nisha E Pillai, Sumanty Tohari, Prashant Shingate, Jianfeng Ren, Byrappa Venkatesh
Studies of the voltage-gated sodium (Nav) channels of extant gnathostomes have made it possible to deduce that ancestral gnathostomes possessed four voltage-gated sodium channel genes derived from a single ancestral chordate gene following two rounds of genome duplication early in vertebrates. We investigated the Nav gene family in two species of lampreys (the Japanese lamprey Lethenteron japonicum and sea lamprey Petromyzon marinus) (jawless vertebrates-agnatha) and compared them with those of basal vertebrates to better understand the origin of Nav genes in vertebrates...
September 27, 2017: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/28883085/hydrodynamic-function-of-dorsal-fins-in-spiny-dogfish-and-bamboo-sharks-during-steady-swimming
#9
Anabela Maia, George V Lauder, Cheryl D Wilga
A key feature of fish functional design is the presence of multiple fins that allow thrust vectoring and redirection of fluid momentum to contribute to both steady swimming and maneuvering. A number of previous studies have analyzed the function of dorsal fins in teleost fishes in this context, but the hydrodynamic function of dorsal fins in freely-swimming sharks has not been analyzed, despite the potential for differential functional roles between the anterior and posterior dorsal fins. Previous anatomical research has suggested a primarily stabilizing role for shark dorsal fins...
September 7, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28855616/similarity-of-morphological-composition-and-developmental-patterning-in-paired-fins-of-the-elephant-shark
#10
Cyrena Riley, Richard Cloutier, Eileen D Grogan
Jawed vertebrates, or gnathostomes, have two sets of paired appendages, pectoral and pelvic fins in fishes and fore- and hindlimbs in tetrapods. As for paired limbs, paired fins are purported serial homologues, and the advent of pelvic fins has been hypothesized to have resulted from a duplication of the developmental mechanisms present in the pectoral fins, but re-iterated at a posterior location. Developmental similarity of gene expression between pectoral and pelvic fins has been documented in chondrichthyans, but a detailed morphological description of the progression of paired fin development for this group is still lacking...
August 30, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28842669/dna-analysis-of-traded-shark-fins-and-mobulid-gill-plates-reveals-a-high-proportion-of-species-of-conservation-concern
#11
Dirk Steinke, Andrea M Bernard, Rebekah L Horn, Paul Hilton, Robert Hanner, Mahmood S Shivji
Continuously increasing demand for plant and animal products causes unsustainable depletion of biological resources. It is estimated that one-quarter of sharks and rays are threatened worldwide and although the global fin trade is widely recognized as a major driver, demand for meat, liver oil, and gill plates also represents a significant threat. This study used DNA barcoding and 16 S rRNA sequencing as a method to identify shark and ray species from dried fins and gill plates, obtained in Canada, China, and Sri Lanka...
August 25, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28807418/assessment-of-metallic-trace-elements-in-the-muscles-and-fins-of-four-landed-elasmobranchs-from-kuala-terengganu-waters-malaysia
#12
Meng Chuan Ong, Shi Ling Gan
A study had been carried out to determine Cu, Zn, Cd, Hg and Pb concentrations in the muscle and fins of four elasmobranchs species namely spot-tail sharks, milk sharks, whitespotted bamboo sharks and whitespotted guitarfish from Pulau Kambing LKIM Fishery Complex, Kuala Terengganu, Malaysia. Zinc level was found to have the highest concentration whereas Cd had the lowest concentration in both organs. By comparing both organs, metals concentrations in fins of all elasmobranchs species were higher than muscle...
November 30, 2017: Marine Pollution Bulletin
https://www.readbyqxmd.com/read/28725435/biogeophysical-and-physiological-processes-drive-movement-patterns-in-a-marine-predator
#13
Lucy A Howey, Bradley M Wetherbee, Emily R Tolentino, Mahmood S Shivji
BACKGROUND: Blue sharks (Prionace glauca) are among the most abundant and widely distributed of oceanic elasmobranchs. Millions are taken annually in pelagic longline fisheries and comprise the highest component of auctioned fin weight in the international shark fin trade. Though studies of blue sharks outnumber those of other large pelagic sharks, the species' complicated and sexually segregated life history still confound current understanding of Atlantic movement patterns. Lack of detailed information regarding movement and vertical behavior continues to limit management efforts that require such data for stock assessment and sustainable catch modeling...
2017: Movement Ecology
https://www.readbyqxmd.com/read/28724735/dual-function-of-the-pectoral-girdle-for-feeding-and-locomotion-in-white-spotted-bamboo-sharks
#14
Ariel L Camp, Bradley Scott, Elizabeth L Brainerd, Cheryl D Wilga
Positioned at the intersection of the head, body and forelimb, the pectoral girdle has the potential to function in both feeding and locomotor behaviours-although the latter has been studied far more. In ray-finned fishes, the pectoral girdle attaches directly to the skull and is retracted during suction feeding, enabling the ventral body muscles to power rapid mouth expansion. However, in sharks, the pectoral girdle is displaced caudally and entirely separate from the skull (as in tetrapods), raising the question of whether it is mobile during suction feeding and contributing to suction expansion...
July 26, 2017: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/28705829/regional-variation-in-undulatory-kinematics-of-two-hammerhead-species-the-bonnethead-sphyrna-tiburo-and-the-scalloped-hammerhead-sphyrna-lewini
#15
S L Hoffmann, S M Warren, M E Porter
Hammerhead sharks (Sphyrnidae) are have a large amount of morpholigcal variation within the family, making them the focus of many studies. The size of the laterally expanded head, or cephalofoil, is inversely correlated with pectoral fin area. The inverse relation in cephalofoil and pectoral fin size in this family suggests that they might serve a complimentary role in lift generation. The cephalofoil is also hypothesized to increase olfaction, electroreception, and vision; however, little is known about how morphological variation impacts post-cranial swimming kinematics...
July 13, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28649268/muscle-development-in-the-shark-scyliorhinus-canicula-implications-for-the-evolution-of-the-gnathostome-head-and-paired-appendage-musculature
#16
Janine M Ziermann, Renata Freitas, Rui Diogo
BACKGROUND: The origin of jawed vertebrates was marked by profound reconfigurations of the skeleton and muscles of the head and by the acquisition of two sets of paired appendages. Extant cartilaginous fish retained numerous plesiomorphic characters of jawed vertebrates, which include several aspects of their musculature. Therefore, myogenic studies on sharks are essential in yielding clues on the developmental processes involved in the origin of the muscular anatomy. RESULTS: Here we provide a detailed description of the development of specific muscular units integrating the cephalic and appendicular musculature of the shark model, Scyliorhinus canicula...
2017: Frontiers in Zoology
https://www.readbyqxmd.com/read/28586694/challenges-and-priorities-in-shark-and-ray-conservation
#17
REVIEW
Nicholas K Dulvy, Colin A Simpfendorfer, Lindsay N K Davidson, Sonja V Fordham, Amie Bräutigam, Glenn Sant, David J Welch
Sharks, rays, and chimaeras (Class Chondrichthyes; herein 'sharks') are the earliest extant jawed vertebrates and exhibit some of the greatest functional diversity of all vertebrates. Ecologically, they influence energy transfer vertically through trophic levels and sometimes trophic cascades via direct consumption and predation risk. Through movements and migrations, they connect horizontally and temporally across habitats and ecosystems, integrating energy flows at large spatial scales and across time. This connectivity flows from ontogenetic growth in size and spatial movements, which in turn underpins their relatively low reproductive rates compared with other exploited ocean fishes...
June 5, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28468932/30-years-of-the-mineralocorticoid-receptor-evolution-of-the-mineralocorticoid-receptor-sequence-structure-and-function
#18
REVIEW
Michael E Baker, Yoshinao Katsu
The mineralocorticoid receptor (MR) is descended from a corticoid receptor (CR), which has descendants in lamprey and hagfish, cyclostomes (jawless fish), a taxon that evolved at the base of the vertebrate line. A distinct MR and GR first appear in cartilaginous fishes (Chondrichthyes), such as sharks, skates, rays and chimeras. Skate MR has a strong response to corticosteroids that are mineralocorticoids and glucocorticoids in humans. The half-maximal responses (EC50s) for skate MR for the mineralocorticoids aldosterone and 11-deoxycorticosterone are 0...
July 2017: Journal of Endocrinology
https://www.readbyqxmd.com/read/28438339/mercury-arsenic-cadmium-and-lead-in-two-commercial-shark-species-sphyrna-lewini-and-caraharinus-porosus-in-trinidad-and-tobago
#19
Azad Mohammed, Terry Mohammed
Sharks are long-lived apex predators which can accumulate toxic metals such as mercury and arsenic. Samples of Sphyrna lewini and Carcharinus porosus were collected from two commercial fish landing sites in Trinidad. Heavy metal concentrations were determined in the muscle, dorsal fin, vertebrae and liver using atomic absorption spectrometric. The provisional tolerable weekly intake (PTWI) and target hazard quotient (THQ) were determined to assess the potential health risks to consumers. Mercury levels ranged between 74-1899μg/kg in S...
April 21, 2017: Marine Pollution Bulletin
https://www.readbyqxmd.com/read/28423077/early-devonian-late-emsian-shark-fin-remains-chondrichthyes-from-the-paran%C3%A3-basin-southern-brazil
#20
Martha Richter, Elvio P Bosetti, Rodrigo S Horodyski
We report on the pioneering discovery of Devonian fish remains in the Paraná Basin, which represents the southernmost record of fishes from that period in mainland South America. The material comes from an outcrop at the lower portion of the São Domingos Formation, within Sequence C of the Paraná-Apucarana sub-basin in Tibagi, State of Paraná. Marine invertebrates are abundant in the same strata. The dark colored fish remains were collected in situ and represent natural moulds of partially articulated shark fin rays (radials)...
January 2017: Anais da Academia Brasileira de Ciências
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