Physiological adaptations of the living agnathans

@article{Hardisty1989PhysiologicalAO,
  title={Physiological adaptations of the living agnathans},
  author={M. W. Hardisty and Ian C. Potter and R. W. Hilliard},
  journal={Earth and Environmental Science Transactions of the Royal Society of Edinburgh},
  year={1989},
  volume={80},
  pages={241 - 254}
}
ABSTRACT The modes of life and environments of the extant agnathans (cyclostomes) are discussed in relation to their adaptations to temperature, light, oxygen and salinity. As their antitropical distribution indicates, both hagfishes and lampreys are cold water groups. Since hagfishes live in deeper waters than lampreys, they are not exposed to the marked seasonal changes in temperature and light which influence major events in the lamprey life cycle. Both groups tend to be nocturnally active… 

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References

SHOWING 1-10 OF 146 REFERENCES

Respiration of Lampreys

In lampreys, though the gross morphology of the branchial chamber and the method of ventilating the gills are radically different from that found in gnathostomes, the total gill area of larval and adult Lampetra fluviatilis and the thickness of the water–blood barrier are similar to active teleosts.

Osmoregulation in Juvenile and Adult Lampreys

Nonparasitic lampreys are well adapted for a freshwater existence but are less tolerant of salt water than representatives of the parasitic species and changes in serum osmolality are primarily the result of corresponding shifts in sodium and chloride ions.

OXYGEN CONSUMPTION DURING THE METAMORPHOSIS OF THE PARASITIC LAMPREY, LAMPETRA FLUVIATILIS (L.) AND ITS NON-PARASITIC DERIVATIVE, LAMPETRA PLANERI (BLOCH)

Standard oxygen consumption and ventilatory frequency were influenced greatly by temperature, e.g. values for stage 6 of L. fluviatilis rose from 24.3 μl g−1 h−1 and 33.0 beats min−1 at 5 °C to 103.8 μlG −1 h −1 and 98.2 beats min −1 at 15 °C.

The Mechanism of Marine Osmoregulation in the Lampern (Lampetra Fluviatilis L.) and the Causes of its Breakdown During the Spawning Migration

An analysis of the mechanism of osmoregulation in fresh-run lamperns shows that it is similar in many respects to that employed by marine teleosts, and it is calculated that chloride is excreted by an extra-renal route, presumably by means of chloride excretory cells which have been discovered in the gills.

On the Feeding of the Hagfish Myxine Glutinosa in the North Sea

  • R. Shelton
  • Environmental Science
    Journal of the Marine Biological Association of the United Kingdom
  • 1978
The myxinoid cyclostomes, of which the hagfish Myxine glutinosa L. is one of the best known examples, are of unique biological interest as representatives of a group of jawless vertebrates which

Studies on an Isolated Spawning Population of the Brook Lamprey (Lampetra planeri)

In the course of physiological work on the brook lamprey (Lampetra planeri) both ammocoetes and adults of this species have been collected in the river Yeo from 1940 onwards, and further restrictions have been placed on their distribution by pollution and by the construction of weirs and sluices.

Hypoxic Acclimation in the Lamprey, Lampetra Fluviatilis: Organismic and Erythrocytic Responses

The intraerythrocytic pH of hypoxic animals, measured with a freeze-thaw method, was higher than the plasma pH, suggesting that protons are not passively distributed, and theHypoxic animals had a higher blood O 2 affinity than the normoxic controls.

Some Aspects of Osmotic Regulation in Lampreys

Evidence has been produced to support the view that the differences observed in water, fat and Cl content of ammocoete and adult planeri and adult fluviatilis are consequences of the period of starvation preceding sexual maturity.

Osmotic Conditions During the Embryonic and Early Larval Life of the Brook Lamprey (Lampetra Planeri)

Evidence is presented which points to a decrease in the volume of the embryo at some point between gastrulation and hatching, and the evidence suggests that the ovarian egg is in osmotic equilibrium with the peritoneal fluid.
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