scholarly journals A Monograph on the Development of Elasmobranch Fishes

Nature ◽  
1878 ◽  
Vol 18 (448) ◽  
pp. 113-115 ◽  
Author(s):  
E. RAY LANKESTER
Keyword(s):  
Elasmobranch Fishes

scholarly journals Elevated carbon dioxide alters the plasma composition and behaviour of a shark

2014 ◽  
Vol 10 (9) ◽  
pp. 20140538 ◽  
Author(s):  
Leon Green ◽  
Fredrik Jutfelt
Keyword(s):  
Ocean Acidification ◽  
Fossil Fuels ◽  
Resting Metabolic Rate ◽  
Blood Chemistry ◽  
Teleost Fishes ◽  
Behavioural Effects ◽  
Swimming Pattern ◽  
Acclimation Period ◽  
Elevated Water ◽  
Elasmobranch Fishes

Increased carbon emissions from fossil fuels are increasing the p CO 2 of the ocean surface waters in a process called ocean acidification. Elevated water p CO 2 can induce physiological and behavioural effects in teleost fishes, although there appear to be large differences in sensitivity between species. There is currently no information available on the possible responses to future ocean acidification in elasmobranch fishes. We exposed small-spotted catsharks ( Scyliorhinus canicula ) to either control conditions or a year 2100 scenario of 990 μatm p CO 2 for four weeks. We did not detect treatment effects on growth, resting metabolic rate, aerobic scope, skin denticle ultrastructure or skin denticle morphology. However, we found that the elevated p CO 2 group buffered internal acidosis via accumulation with an associated increase in Na + , indicating that the blood chemistry remained altered despite the long acclimation period. The elevated p CO 2 group also exhibited a shift in their nocturnal swimming pattern from a pattern of many starts and stops to more continuous swimming. Although CO 2 -exposed teleost fishes can display reduced behavioural asymmetry (lateralization), the CO 2 -exposed sharks showed increased lateralization. These behavioural effects may suggest that elasmobranch neurophysiology is affected by CO 2 , as in some teleosts, or that the sharks detect CO 2 as a constant stressor, which leads to altered behaviour. The potential direct effects of ocean acidification should henceforth be considered when assessing future anthropogenic effects on sharks.

scholarly journals SPECTRAL SENSITIVITY OF TWO SPECIES OF ELASMOBRANCH FISHES

1966 ◽  
Vol 32 (3) ◽  
pp. 260-261 ◽  
Author(s):  
Tamotsu TAMURA ◽  
Isao HANYU ◽  
Hiroshi NIWA
Keyword(s):  
Spectral Sensitivity ◽  
Elasmobranch Fishes

Periodic gonadal activity and protracted mating in elasmobranch fishes

1996 ◽  
Vol 276 (3) ◽  
pp. 219-232 ◽  
Author(s):  
Karen P. Maruska ◽  
Elizabeth G. Cowie ◽  
Timothy C. Tricas
Keyword(s):  
Gonadal Activity ◽  
Elasmobranch Fishes

scholarly journals Digenea and acanthocephala of elasmobranch fishes from the southern coast of Brazil

2001 ◽  
Vol 96 (8) ◽  
pp. 1095-1101 ◽  
Author(s):  
Marcelo Knoff ◽  
Sérgio Carmona de São Clemente ◽  
Roberto Magalhães Pinto ◽  
Delir Corrêa Gomes
Keyword(s):  
Southern Coast ◽  
Elasmobranch Fishes

scholarly journals Upon the structure and development of the enamel of Elasmobranch fishes

1898 ◽  
Vol 63 (389-400) ◽  
pp. 54-56
Keyword(s):  
Optical Properties ◽  
Outer Layer ◽  
Weak Acids ◽  
Physical Chemical ◽  
Elasmobranch Fishes

The nature of the hard polished outer layer of the teeth of this group of fishes has been from time to time a subject of discussion, some authors holding that it is enamel, whilst others deny its claim to be so styled. The author describes its physical, chemical, and histological peculiarities, calling attention to its hardness, its optical properties, its almost entire solubility in weak acids, and to its tubularity, in all of which respects it resembles unquestionably an enamel.

scholarly journals VIII.—On the calcification of the vertebral centra in sharks and rays

1921 ◽  
Vol 210 (372-381) ◽  
pp. 311-407 ◽  
Keyword(s):  
Natural History ◽  
Research Laboratory ◽  
British Museum ◽  
Imperial College ◽  
Vertebral Centra ◽  
The Subject ◽  
Elasmobranch Fishes ◽  
Fossil State

In this paper are recorded the results of an investigation undertaken at the instance of Dr. A. Smith Woodward for the purpose of ascertaining to what extent the pattern presented by the calcified laminæ of the centrum is of value as an aid to the classification of Elasmobranch fishes, and to the identification of vertebræ found in the fossil state. The subject was dealt with exhaustively in 1879-1885 by Hasse, who, in his monograph ‘Das natürliche System der Elasmobranchier,’ claimed that the differences in the disposition of the calcified laminæ in the various genera and families of Elasmobranchs occur with such constancy and regularity that they may be accepted with confidence as an important factor in taxonomy. During the years, however, that have passed since the publication of this monograph the thesis has come to be looked upon with suspicion, and vertebrate morphologists at the present time do not, as a whole, regard Hasse’s definitions of the Cyclospondyli, Tectospondyli, and Asterospondyli as consistently applicable to the genera and species included by him within those groups. The material studied in the course of the investigation was to a large extent accumulated several years ago (see p. 313), and it was only the superior attraction of Cephalodiscus as a subject of research that prevented the work from being brought to an earlier conclusion. The examination of this accumulated material, and of that more recently acquired, was carried on in the Huxley Research Laboratory of the Imperial College of Science during the winter of 1917 and from May, 1919, to May, 1920, and I hereby acknowledge my great indebtedness to Prof. E. W. MacBride and the administrative officers of the College for the facilities offered there for the prosecution of the work. I have further to thank Prof. MacBride for frequent advice and for valuable suggestions made during the progress of the research. My thanks are also due, and are hereby tendered, to Dr. A. Smith Woodward and Mr. C. Tate Began, of the British Museum (Natural History), for many helpful hints and suggestions. Acknowledgments and thanks for material kindly furnished by various donors are recorded on p. 313.

An Overview of the Feeding Ecology and Physiology of Elasmobranch Fishes

2008 ◽  
pp. 393-443 ◽  
Author(s):  
Enric Cortés ◽  
Yannis Papastamatiou ◽  
John Carlson ◽  
Lara Ferry-Graham ◽  
Bradley Wetherbee
Keyword(s):  
Feeding Ecology ◽  
Elasmobranch Fishes

Ventilatory modes and mechanics of the hedgehog skate (Leucoraja erinacea): testing the continuous flow model

2001 ◽  
Vol 204 (9) ◽  
pp. 1577-1587 ◽  
Author(s):  
A.P. Summers ◽  
L.A. Ferry-Graham
Keyword(s):  
System Design ◽  
Continuous Flow ◽  
Flow Model ◽  
Pressure Measurements ◽  
Suction Pump ◽  
Experimental Animals ◽  
Pressure Transducers ◽  
Oropharyngeal Cavity ◽  
Elasmobranch Fishes ◽  
System 1

The movement of water across the gills of non-ram-ventilating fishes involves the action of two pumps: a pressure pump that pushes water across the gills from the oropharyngeal to the parabranchial cavity, and a suction pump that draws water across the gills from the oropharyngeal into the parabranchial cavity. Together, the two are thought to keep water flowing continuously anteroposteriorly through the head of the respiring animal. However, there is evidence that the pressure and suction pumps do not always work in perfect phase in elasmobranch fishes, leading to periods of higher pressure in the parabranchial than in the oropharyngeal cavity. We investigated the existence and consequence of such pressure reversals in the hedgehog skate Leucoraja erinacea using pressure transducers, sonomicrometry and flow visualization including internal visualization using endoscopy. We noted four patterns of respiration in the experimental skates distinguished by the flow pattern at the three openings into the respiratory system: (1) in through the spiracle only, (2) in through the mouth + spiracle, (3) in through the mouth only, and (4) the mouth held open throughout the respiratory cycle. The first two were by far the dominant modes recorded from experimental animals. We determined that pressure reversals exist in the hedgehog skate, and that the gill bars adducted during such pressure reversals. Direct observation confirmed that these pressure reversals do correspond to pulsatile flow across the gills. During mouth+spiracle ventilation the flow completely reversed direction, flowing from the parabranchial chambers back across the gills and into the oropharyngeal cavity. Finally, we addressed the utility of sonomicrometry as a technique for determining kinematics in aquatic animals. Despite some problems involving errors inherent to the system design, we found the technique useful for complementing such techniques as pressure measurements and endoscopy.

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