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Elasmobranch

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https://www.readbyqxmd.com/read/29334823/a-new-genus-of-tapeworm-cestoda-onchoproteocephalidea-from-sawfish-elasmobranchii-pristidae
#1
Janine N Caira, Kirsten Jensen, Carolyn A Fyler
Collections from the dwarf sawfish, Pristis clavata, near Darwin, Australia in 1997 led to the discovery of the new onchoproteocephalidean genus Matticestus n. gen.-a taxon that has been referred to in molecular phylogenetic analyses in which it has been included as "New genus 8." Its type species, Matticestus anneae n. gen., n. sp., and a second species, Matticestus kathleenae n. sp. are described. Placement of this taxon in the Onchoproteocephalidea is supported morphologically in that both species bear a scolex with 4 bothridia each with a pair of bipronged hooks and spinitriches that extend throughout the length of the body...
January 15, 2018: Journal of Parasitology
https://www.readbyqxmd.com/read/29329295/novel-signature-fatty-acid-profile-of-the-giant-manta-ray-suggests-reliance-on-an-uncharacterised-mesopelagic-food-source-low-in-polyunsaturated-fatty-acids
#2
Katherine B Burgess, Michel Guerrero, Andrea D Marshall, Anthony J Richardson, Mike B Bennett, Lydie I E Couturier
Traditionally, large planktivorous elasmobranchs have been thought to predominantly feed on surface zooplankton during daytime hours. However, the recent application of molecular methods to examine long-term assimilated diets, has revealed that these species likely gain the majority from deeper or demersal sources. Signature fatty acid analysis (FA) of muscle tissue was used to examine the assimilated diet of the giant manta ray Mobula birostris, and then compared with surface zooplankton that was collected during feeding and non-feeding events at two aggregation sites off mainland Ecuador...
2018: PloS One
https://www.readbyqxmd.com/read/29324879/localized-zinc-distribution-in-shark-vertebrae-suggests-differential-deposition-during-ontogeny-and-across-vertebral-structures
#3
Vincent Raoult, Nicholas Howell, David Zahra, Victor M Peddemors, Daryl L Howard, Martin D de Jonge, Benjamin L Buchan, Jane E Williamson
The development of shark vertebrae and the possible drivers of inter- and intra-specific differences in vertebral structure are poorly understood. Shark vertebrae are used to examine life-history traits related to trophic ecology, movement patterns, and the management of fisheries; a better understanding of their development would be beneficial to many fields of research that rely on these calcified structures. This study used Scanning X-ray Fluorescence Microscopy to observe zinc distribution within vertebrae of ten shark species from five different orders...
2018: PloS One
https://www.readbyqxmd.com/read/29297831/whole-blood-transfusions-to-treat-severe-anemia-in-seven-cownose-rays-rhinoptera-bonasus-and-one-short-tail-stingray-dasyatis-brevicaudata
#4
Alexa J McDermott Delaune, Cara L Field, Tonya M Clauss
Blood transfusions can provide life-saving treatment to severely anemic animals. Due to limited availability and the difficulty of storing whole blood and blood products, such as fresh frozen plasma and packed red blood cells, exotic animals often receive fresh whole blood transfusions. Little is known about elasmobranch blood types and transfusions. Conspecific cross-matches within several different elasmobranch species were negative, indicating that in an emergency situation a single whole blood transfusion may be possible without causing a transfusion reaction...
December 2017: Journal of Zoo and Wildlife Medicine: Official Publication of the American Association of Zoo Veterinarians
https://www.readbyqxmd.com/read/29277002/distribution-of-anisakid-nematodes-parasitizing-rajiform-skates-under-commercial-exploitation-in-the-southwestern-atlantic
#5
Manuel Marcial Irigoitia, Paola Elizabeth Braicovich, Ana Laura Lanfranchi, Marisa Diana Farber, Juan Tomás Timi
In order to evaluate the infestation by anisakids present in elasmobranchs and their distribution in the Argentine Sea, this study was carried at a regional scale with the following aims: 1) to identify those anisakid species present in skates under exploitation; 2) to characterize quantitatively these infestations and 3) to determine those factors driving the variability in parasite burdens across skate species. A total of 351 skates, belonging to 3 species (218 Sympterygia bonapartii, 86 Zearaja chilensis and 47 Atlantoraja castelnaui) and from different localities of the Argentine Sea were examined for anisakids...
December 19, 2017: International Journal of Food Microbiology
https://www.readbyqxmd.com/read/29248570/synthetic-capacity-does-not-predict-elasmobranchs-ability-to-maintain-trimethylamine-oxide-without-a-dietary-contribution
#6
Abigail B Bockus, Brad A Seibel
Trimethylamine oxide (TMAO) is an organic osmolyte and universal protein stabilizer. Its role as a cytoprotectant is particularly important in ureosmotic elasmobranchs that accumulate high levels of urea, a macromolecular perturbant. Feeding is a key component in the turnover and maintenance of these nitrogenous compounds. However, previous studies examining TMAO regulation have been largely completed using starved individuals, when nitrogen balance is altered. Here, under fed conditions, we test the importance of dietary TMAO on long-term maintenance in three elasmobranch species with differing endogenous synthetic capacities...
December 14, 2017: Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology
https://www.readbyqxmd.com/read/29236865/microscopic-aspects-of-electrosensory-system-on-the-partially-euryhaline-lesser-guitarfish
#7
Bianca S Rangel, Natascha Wosnick, Alberto F Amorim, José Roberto K, Rose E G Rici
The electrosensory system on elasmobranchs consists of subcutaneous electroreceptor organs known as ampullae of Lorenzini. The present study investigated the ampullae of Lorenzini morphology of the lesser guitarfish Zapteryx brevirostris, using light microscopy and scanning electron microscopy. The pore number found in the ventral skin surface is much higher than that found in the dorsal portion, characteristic of species that inhabit the euphotic zone. Under light microscopy it was possible to observe that the wall canal consists of a single layer of squamous epithelial cells...
December 7, 2017: Anais da Academia Brasileira de Ciências
https://www.readbyqxmd.com/read/29232670/some-galeomorph-sharks-express-a-mammalian-microglia-specific-protein-in-radial-ependymoglia-of-the-telencephalon
#8
Skirmantas Janušonis
Ionized calcium-binding adapter molecule 1 (Iba1), also known as allograft inflammatory factor 1 (AIF-1), is a highly conserved cytoplasmic scaffold protein. Studies strongly suggest that Iba1 is associated with immune-like reactions in all Metazoa. In the mammalian brain, it is abundantly expressed in microglial cells and is used as a reliable marker for this cell type. The present study used multiple-label microscopy and Western blotting to examine Iba1 expression in the telencephalon of 2 galeomorph shark species, the swellshark (Cephaloscyllium ventriosum) and the horn shark (Heterodontus francisci), a member of an ancient extant order...
December 13, 2017: Brain, Behavior and Evolution
https://www.readbyqxmd.com/read/29216310/gbm-auto-a-software-tool-to-simplify-spatial-modelling-and-marine-protected-area-planning
#9
Simon Dedman, Rick Officer, Maurice Clarke, David G Reid, Deirdre Brophy
BOOSTED REGRESSION TREES. EXCELLENT FOR DATA-POOR SPATIAL MANAGEMENT BUT HARD TO USE: Marine resource managers and scientists often advocate spatial approaches to manage data-poor species. Existing spatial prediction and management techniques are either insufficiently robust, struggle with sparse input data, or make suboptimal use of multiple explanatory variables. Boosted Regression Trees feature excellent performance and are well suited to modelling the distribution of data-limited species, but are extremely complicated and time-consuming to learn and use, hindering access for a wide potential user base and therefore limiting uptake and usage...
2017: PloS One
https://www.readbyqxmd.com/read/29205335/melanomacrophage-functions-in-the-liver-of-the-caecilian-siphonops-annulatus
#10
Robson Campos Gutierre, Carlos Jared, Marta Maria Antoniazzi, Antonio Augusto Coppi, Mizue Imoto Egami
Melanomacrophages are phagocytes that synthesize melanin. They are found in the liver and spleen of ectothermic vertebrates, and in the kidney of fish. In agnathan and elasmobranch fish, melanomacrophages are seen as isolated cells, and forming clusters in all the other vertebrates. The natural phagocytic activity of melanomacrophages is poorly characterized, as most of the research works have focused on induced phagocytic activity only. Furthermore, little is known about amphibian melanomacrophages, mainly about those in caecilians - wormlike amphibians in the order of Gymnophiona, which is the least known group of terrestrial vertebrates...
December 4, 2017: Journal of Anatomy
https://www.readbyqxmd.com/read/29118464/eocene-squalomorph-sharks-chondrichthyes-elasmobranchii-from-antarctica
#11
Andrea Engelbrecht, Thomas Mörs, Marcelo A Reguero, Jürgen Kriwet
Rare remains of predominantly deep-water sharks of the families Hexanchidae, Squalidae, Dalatiidae, Centrophoridae, and Squatinidae are described from the Eocene La Meseta Formation, Seymour Island, Antarctic Peninsula, which has yielded the most abundant chondrichthyan assemblage from the Southern Hemisphere to date. Previously described representatives of Hexanchus sp., Squalus weltoni, Squalus woodburnei, Centrophorus sp., and Squatina sp. are confirmed and dental variations are documented. Although the teeth of Squatina sp...
October 2017: Journal of South American Earth Sciences
https://www.readbyqxmd.com/read/29056144/sharks-in-captivity-the-role-of-husbandry-breeding-education-and-citizen-science-in-shark-conservation
#12
Michael Grassmann, Bryan McNeil, Jim Wharton
The role of public aquariums in promoting conservation has changed substantially over the decades, evolving from entertainment attractions to educational and research centres. In many facilities, larger sharks are an essential part of the collection and represent one of the biggest draws for the public. Displaying healthy elasmobranchs comes with many challenges, but improvements in husbandry techniques have enabled aquariums to have success with a variety of species. The establishment of organisations such as the Association of Zoos and Aquariums, and the completion of texts like the Elasmobranch Husbandry Manual, has helped set high standards of care for sharks in captivity and promoted international conservation efforts...
2017: Advances in Marine Biology
https://www.readbyqxmd.com/read/29056143/an-introduction-to-modelling-abundance-and-life-history-parameters-in-shark-populations
#13
Dovi Kacev, Timothy J Sippel, Michael J Kinney, Sebastián A Pardo, Christopher G Mull
Elasmobranchs play critically important ecological roles throughout the world's oceans, yet in many cases, their slow life histories and interactions with fisheries makes them particularly susceptible to exploitation. Management for these species requires robust scientific input, and mathematical models are the backbone of science-based management. In this chapter, we provide an introductory overview of the use of mathematical models to estimate shark abundance. First, we discuss life history models that are used to understand the basic biology of elasmobranchs...
2017: Advances in Marine Biology
https://www.readbyqxmd.com/read/29044046/locally-extensive-meningoencephalitis-caused-by-miamiensis-avidus-syn-philasterides-dicentrarchi-in-a-zebra-shark
#14
Wen-Ta Li, Chieh Lo, Chen-Yi Su, Hsuan Kuo, Susanne Je-Han Lin, Hui-Wei Chang, Victor Fei Pang, Chian-Ren Jeng
Scuticociliatosis, caused by ciliated protozoa in the subclass Scuticociliatia of the phylum Ciliophora, can cause fatal disease in teleost fish species. However, information on scuticociliatosis in elasmobranchs is still scarce. In this report, we describe a case of locally extensive meningoencephalitis caused by Miamiensis avidus (syn. Philasterides dicentrarchi) in a 2 yr old captive zebra shark Stegostoma fasciatum. Granulocytic meningoencephalitis was observed through histological assessment. Inflammation was confined to the ventral aspect of the brain with a large number of ciliated protozoa, transforming into non-suppurative meningitis in the lateral aspect, and gradually vanished in the dorsal aspect...
October 18, 2017: Diseases of Aquatic Organisms
https://www.readbyqxmd.com/read/29034467/first-insights-into-the-function-of-the-sawshark-rostrum-through-examination-of-rostral-tooth-microwear
#15
R J Nevatte, B E Wueringer, D E Jacob, J M Park, J E Williamson
Potential roles of the rostrum of sawsharks (Pristiophoridae), including predation and self-defence, were assessed through a variety of inferential methods. Comparison of microwear on the surface of the rostral teeth of sawsharks and sawfishes (Pristidae) show that microwear patterns are alike and suggest that the elongate rostra in these two elasmobranch families are used for a similar purpose (predation). Raman spectroscopy indicates that the rostral teeth of both sawsharks and sawfishes are composed of hydroxyapatite, but differ in their collagen content...
October 16, 2017: Journal of Fish Biology
https://www.readbyqxmd.com/read/29023719/natural-variability-and-effects-of-cleaning-and-storage-procedures-on-vertebral-chemistry-of-the-blacktip-shark-carcharhinus-limbatus
#16
J P Lewis, W F Patterson, J K Carlson
Key methodological assumptions regarding the degree of natural variability and influence of sample handling and storage of elasmobranch vertebral chemistry were assessed using laser-ablation inductively coupled plasma mass spectrometry. Vertebral chemistry of juvenile blacktip sharks Carcharhinus limbatus was examined to identify whether differences existed among different regions of the vertebral column, between thoracic vertebrae of individual fish or within individual vertebrae. Additionally, the effects of bleach exposure and storage in ethanol on vertebral chemistry were compared...
October 10, 2017: Journal of Fish Biology
https://www.readbyqxmd.com/read/29023598/the-greenland-shark-somniosus-microcephalus-hemoglobins-and-ligand-binding-properties
#17
Roberta Russo, Daniela Giordano, Gianluca Paredi, Francesco Marchesani, Lisa Milazzo, Giovanna Altomonte, Pietro Del Canale, Stefania Abbruzzetti, Paolo Ascenzi, Guido di Prisco, Cristiano Viappiani, Angela Fago, Stefano Bruno, Giulietta Smulevich, Cinzia Verde
A large amount of data is currently available on the adaptive mechanisms of polar bony fish hemoglobins, but structural information on those of cartilaginous species is scarce. This study presents the first characterisation of the hemoglobin system of one of the longest-living vertebrate species (392 ± 120 years), the Arctic shark Somniosus microcephalus. Three major hemoglobins are found in its red blood cells and are made of two copies of the same α globin combined with two copies of three very similar β subunits...
2017: PloS One
https://www.readbyqxmd.com/read/28989770/large-batoid-fishes-frequently-consume-stingrays-despite-skeletal-damage
#18
Mason N Dean, Joseph J Bizzarro, Brett Clark, Charlie J Underwood, Zerina Johanson
The shapes of vertebrate teeth are often used as hallmarks of diet. Here, however, we demonstrate evidence of frequent piscivory by cartilaginous fishes with pebble-like teeth that are typically associated with durophagy, the eating of hard-shelled prey. High-resolution micro-computed tomography observation of a jaw specimen from one batoid species and visual investigation of those of two additional species reveal large numbers of embedded stingray spines, arguing that stingray predation of a scale rivalling that of the largest carnivorous sharks may not be uncommon for large, predatory batoids with rounded, non-cutting dentition...
September 2017: Royal Society Open Science
https://www.readbyqxmd.com/read/28972451/differential-effects-of-temperature-on-oxygen-consumption-and-branchial-fluxes-of-urea-ammonia-and-water-in-the-dogfish-shark-squalus-acanthias-suckleyi
#19
Marina Giacomin, Patricia M Schulte, Chris M Wood
Environmental temperature can greatly influence the homeostasis of ectotherms through its effects on biochemical reactions and whole-animal physiology. Elasmobranchs tend to be N limited and are osmoconformers, retaining ammonia and urea-N at the gills and using the latter as a key osmolyte to maintain high blood osmolality. However, the effects of temperature on these key processes remain largely unknown. We evaluated the effects of acute exposure to different temperatures (7°, 12°, 15°, 18°, 22°C) on oxygen consumption, ammonia, urea-N, and diffusive water fluxes at the gills of Squalus acanthias suckleyi...
November 2017: Physiological and Biochemical Zoology: PBZ
https://www.readbyqxmd.com/read/28970537/migratory-appendicular-muscles-precursor-cells-in-the-common-ancestor-to-all-vertebrates
#20
Eri Okamoto, Rie Kusakabe, Shigehiro Kuraku, Susumu Hyodo, Alexandre Robert-Moreno, Koh Onimaru, James Sharpe, Shigeru Kuratani, Mikiko Tanaka
In amniote embryos, skeletal muscles in the trunk are derived from epithelial dermomyotomes, the ventral margin of which extends ventrally to form body wall muscles. At limb levels, ventral dermomyotomes also generate limb-muscle precursors, an Lbx1-positive cell population that originates from the dermomyotome and migrates distally into the limb bud. In elasmobranchs, however, muscles in the paired fins were believed to be formed by direct somitic extension, a developmental pattern used by the amniote body wall muscles...
October 2, 2017: Nature Ecology & Evolution
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