A new paraclupeid fish (Clupeomorpha, Ellimmichthyiformes) from a muddy marine pro-delta environment: middle Cenomanian Dunvegan Formation, Alberta, Canada

2007 ◽  
Vol 44 (6) ◽  
pp. 775-790 ◽  
Author(s):  
Michael J Hay ◽  
Stephen L Cumbaa ◽  
Alison M Murray ◽  
A Guy Plint

A black marine mudstone in allomember A of the middle Cenomanian Dunvegan Formation, Alberta, yielded a well-preserved, deep-bodied fish skeleton attributable to a new genus and species, Tycheroichthys dunveganensis, in the Paraclupeidae (Clupeomorpha, Ellimmichthyiformes). This new taxon appears most closely related to members of the subfamily Paraclupeinae, which includes largely freshwater and estuarine or marginal marine species known from South and Central America and China. The Dunvegan Formation represents a large delta complex deposited in the Western Interior Seaway at about 65°N, where mean sea water temperature may have been about 10 °C. The specimen was found about 60 km from the contemporaneous shoreline, and, in life, apparently inhabited a shallow, muddy pro-delta environment characterized by high turbidity and variable salinity. The fish may have died when it was engulfed by brackish floodwater that also introduced suspended mud that rapidly buried the body, preventing physical disarticulation of the skeleton. River outflow probably produced a salinity- and density-stratified water column that limited oxygen transfer to the sea floor, leading to dysaerobic bottom water and an absence of scavengers. High terrestrial phytodetrital content of the sediment also favoured anaerobic conditions that limited bacterial decay.

1934 ◽  
Vol 11 (4) ◽  
pp. 364-381
Author(s):  
J. A. KITCHING

1. The rate of output of fluid from the contractile vacuole of a fresh-water Peritrich Ciliate was decreased to a new steady value immediately the organism was placed in a mixture of tap water and sea water. The rate of output returned to its original value immediately the organism was replaced in tap water. The contractile vacuole was stopped when the organism was treated with a mixture containing more than 12 per cent, of sea water. 2. Transference of various species of marine Peritricha from 100 per cent, sea water to mixtures of sea water and tap water led to an immediate increase of the body volume to a new and generally steady value. Return of the organism to 100 per cent, sea water led to an immediate decrease of the body volume to its original value or less. 3. Marine Peritricha showed little change in rate of output when treated with concentrations of sea water between 100 and 75 per cent. In more dilute mixtures the rate of output was immediately increased, and then generally fell off slightly to a new steady value which was still considerably above the original (100 per cent. sea water) value. The maximum sustained increase was approximately x 80. Return of the organism to 100 per cent, sea water led to an immediate return of the rate of output to approximately its original value. 4. When individuals of some marine species were placed in very dilute concentrations of sea water, the pellicle was frequently raised up in blisters by the formation of drops of fluid underneath it, and the contractile vacuole stopped. 5. Evidence is brought forward to suggest that in the lower concentrations of sea water marine forms lost salts. 6. The contractile vacuole probably acts as an osmotic controller in fresh-water Protozoa. Its function in those marine Protozoa in which it occurs remains obscure.


1969 ◽  
Vol 50 (3) ◽  
pp. 689-703 ◽  
Author(s):  
DAVID H. EVANS

Measurements were made of the flux of tritiated water across various marine, freshwater and euryhaline teleosts. The effects of temperature, body size, species differences, salinity, stress and anaesthetization were studied. 2. The Q10 of the flux of water across teleosts is approximately 1·90 and the flux is related to the 0·88 power of the body weight. 3. All of the freshwater species studied were more permeable to water than the marine species. Euryhaline teleosts appear to have about the same permeability as species to which they are most closely related. 4. While the flounder and the yellow eel are more permeable to water in fresh water than in sea water, the silver eel and the brown trout do not change their permeability and the 3-spined stickleback is less permeable to water in fresh water than in sea water. 5. While stress markedly increases the permeability to water of large brown trout, it has no effect on small brown trout and seems to decrease the water permeability of the plaice. 6. Anaesthetization has no effect on the water permeability of the goldfish but markedly increases the permeability to water of the silver eel. 7. The relationship between the flux of water and either the drinking rate in sea water or the urine flow in fresh water is discussed.


2020 ◽  
Vol 7 ◽  
Author(s):  
Tengyue Zhang ◽  
Yurui Wang ◽  
Ting Cheng ◽  
Jiyang Ma ◽  
Peter Vd’ačný ◽  
...  

Morphogenesis of ciliated protists attracts a lot of attention, because their huge morphological diversity is related to formation of ciliary structures during cell division. In the present work, the morphology and morphogenesis as well as the phylogenetic position of a new, marine hypotrich ciliate, Nothoholosticha luporinii n. sp., were investigated. The new species is characterized by having a combination of the following features: a bicorona whose anterior row contains four frontal cirri and posterior row includes only two cirri, a single buccal cirrus, midventral complex composed of about 30 cirral pairs, one pretransverse cirrus, 3–6 transverse cirri, one left and one right marginal cirral row; three bipolar dorsal kineties; contractile vacuole located in about 2/3 of the body length, two types of cortical granules, and many macronuclear nodules scattered throughout the cytoplasm. The morphogenesis of N. luporinii follows the ontogenetic mode of Pseudokeronopsis, a well-known and closely related genus except that the macronucleus fuses into a single mass in the middle fission stage. Phylogenetic analyses based on the rDNA operon classify Nothoholosticha in the family Pseudokeronopsidae and support the distinctness of the new taxon as well as the monophyletic origin of the subfamily Nothoholostichinae.


1968 ◽  
Vol 48 (2) ◽  
pp. 359-380
Author(s):  
D. W. SUTCLIFFE

1. Sodium uptake and loss rates are given for three gammarids acclimatized to media ranging from fresh water to undiluted sea water. 2. In Gammarus zaddachi and G. tigrinus the sodium transporting system at the body surface is half-saturated at an external concentration of about 1 mM/l. and fully saturated at about 10 mM/l. sodium. In Marinogammarus finmarchicus the respective concentrations are six to ten times higher. 3. M. finmarchicus is more permeable to water and salts than G. zaddachi and G. tigrinus. Estimated urine flow rates were equivalent to 6.5% body weight/hr./ osmole gradient at 10°C. in M. finmarchicus and 2.8% body weight/hr./osmole gradient in G. zaddachi. The permeability of the body surface to outward diffusion of sodium was four times higher in M. finmarchicus, but sodium losses across the body surface represent at least 50% of the total losses in both M. finmarchicus and G. zaddachi. 4. Calculations suggest that G. zaddachi produces urine slightly hypotonic to the blood when acclimatized to the range 20% down to 2% sea water. In fresh water the urine sodium concentration is reduced to a very low level. 5. The process of adaptation to fresh water in gammarid crustaceans is illustrated with reference to a series of species from marine, brackish and freshwater habitats.


Author(s):  
G. W. Bryan ◽  
L. G. Hummerstone ◽  
Eileen Ward

Zinc is one of the most important of the essential trace metals and more than 90 zinc-containing enymes and proteins have been discovered: furthermore, zinc increases the activity of many other enzymes (Vallee, 1978). It is not surprising, therefore, that in some groups of animals the body concentration is regulated against fluctuations in intake. Decapod crustaceans comprise one such group, although the ways in which regulation is achieved vary from species to species. In the freshwater crayfish, Austropotamobius pallipes, excretion in the faeces is a major pathway for removing zinc (Bryan, 1967a) whereas in the shore crab Carcinus maenas losses over the body surface also assume considerable importance (Bryan, 1966). On the other hand, preliminary work on the lobster Homarus gammarus (formerly H. vulgaris) suggests that in this species urinary excretion plays a major role in regulation (Bryan, 1964). The present work continues the study of zinc regulation in lobsters and its main aims are: (1) to measure rates of absorption from sea water over a wide range of concentrations and study the uptake mechanism; (2) to examine absorption from the stomach under different conditions; (3) to determine the relative importance of different pathways for the removal of zinc in response to various levels of intake.


Author(s):  
D. F. Jefferies ◽  
C. J. Hewett

INTRODUCTIONThe caesium radionuclides, caesium-137 and caesium-134, are important constituents of aqueous radioactive effluents discharged to the environment of the United Kingdom from fuel re-processing plants and nuclear power stations (Howells, 1966; Mitchell, Harvey & Smith, 1968; Harvey, Baker & Mitchell, 1969). Their accumulation by marine fishes has been the subject of several previous studies, beginning with that of Chipman (1959) who noted that caesium-137 was accumulated in the flesh of the killifish (Fundulus heteroclitus) and that accumulation continued even after a period of 72 days. Similarly, Hiyama & Shimizu (1964) showed that the muscle of the common goby (Acanthobus flaviamus) continued to accumulate caesium-134 from sea water after periods of 30 days. Baptist & Price (1962) have examined the whole body uptake of caesium, by absorption from sea water, in two marine species, the flounder (Paralichthys dentatus) and the Atlantic croaker (Micropogon undulatus), and they also investigated the accumulation, tissue distribution and excretion of caesium-137 in the croaker, the little tuna (Euthynnus alleteratus) and the bluefish (Pomatomus saltatoux), following oral administration of single doses. These authors concluded that the heart, liver and spleen of the croaker absorbed caesium-137 from sea water at a faster rate than the muscle, and that orally administered caesium-137 was rapidly absorbed from the digestive tract. Tissue distributions were similar in the croaker, bluefish and tuna. The retention of caesium-137 in croaker tissue was described as a multiple rate process. In later experiments Hiyama & Shimizu (1969) compared turnover rates in various organs and tissues following uptake from sea water and from single injection experiments, and obtained good agreement between the values from the two methods.


Author(s):  
M. R. Clarke ◽  
E. J. Denton ◽  
J. B. Gilpin-Brown

Squids (teuthoids) fall into two distinct groups according to their density in sea water. Squids of one group are considerably denser than sea water and must swim to stop sinking; squids in the other group are nearly neutrally buoyant. Analyses show that in almost all the neutrally buoyant squids large amounts of ammonium are present. This ammonium is not uniformly distributed throughout the body but is mostly confined to special tissues where its concentration can approach half molar. The locations of such tissues differ according to the species and developmental stage of the squid. It is clear that the ammonium-rich solution are almost isosmotic with sea water but of lower density and they are present in sufficient volume to provide the main buoyancy mechanism of these squids. A variety of evidence is given which suggests that squids in no less than 12 of the 26 families achieve near-neutral buoyancy in this way and that 14 families contain squids appreciably denser than sea water [at least one family contains both types of squid]. Some of the ammonium-rich squids are extremely abundant in the oceans.


Author(s):  
G. W. Bryan

The relationship between the ability of brackish water invertebrates to regulate Na and K and the extent to which the radioactive fission product 137Cs can be accumulated has been studied.The brackish water isopod Sphaeroma hookeri and the gastropod Potamopyrgus jenkinsi have been acclimatised to a wide range of sea-water dilutions. Unfed Sphaeroma can survive in sea-water concentrations of 100–2·5%, while Potamopyrgus can live fairly indefinitely in concentrations of 50–0·1%. Measurements of Na and K in the whole animals of both species and in the blood of Sphaeroma have been made. Salt movements are quite rapid and acclimatization to new media is achieved by both species in less than 10 h. Concentration factors for inactive K in particular increase to high values in the more dilute media.Uptake of the isotopes 42K and 137Cs from solution has been examined in both species over a range of sea-water concentrations. All of the body K is exchangeable with 42K and in Sphaeroma exchange of 42K between the blood and tissues is so rapid that the body surface appears to be the limiting factor in the uptake of the isotope. Both species exchange 42K more rapidly in the higher concentrations of sea water and one reason for this may be the existence of an exchange diffusion component of exchange which increases as the salinity of the medium is raised. Indirect evidence suggests that the excretion of 42K in urine is probably not an important factor in exchange.


1972 ◽  
Vol 57 (1) ◽  
pp. 83-102
Author(s):  
H. J. FYHN ◽  
J. A. PETERSEN ◽  
K. JOHANSEN

1. Physiological responses to environmental stresses of the intertidal cirriped Pollicipes polymerus have been studied by combined field and laboratory experiments. 2. The body temperature of air-exposed animals is always lower than expected from the heat load. Evaporation from the peduncle is responsible for the heat loss. 3. The rate of water loss by evaporation from the peduncle cuticle is 1.5 µl/cm2 h mmHg both at 21 and 27 °C. The transpiration is proportional to the saturation deficit of the air. The water loss from the capitulum is negligible in comparison to that from the peduncle. 4. The haemolymph osmolality of animals in the field increases during exposure to sunshine and decreases during exposure to rain. The increase in haemolymph osmolality during desiccation is equal to that calculated from the decrease in body water. The water loss during air exposure is adequately replaced during submersion, probably by osmosis. 5. Pollicipes is an osmoconformer but is 5-20 m-osmoles hyperosmotic. It tolerates sea-water dilutions down to about 50%. The hyperosmolality seems to be balanced by a high internal hydrostatic pressure. 6. An excretory activity is observed. The excretion is isosmotic to the haemolymph and is possibly an ultrafiltrate of the latter. 7. The muscle cells show volume regulation, but free amino acids seem to be unimportant in regulation of intracellular osmolality. The concentration of ninhydrinpositive substances in the muscle tissue is about 200 mM for animals in full strength sea water.


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