Search results for "Actinopterygii"
showing 10 items of 210 documents
Permian-Triassic Osteichthyes (bony fishes): diversity dynamics and body size evolution
2014
The Permian and Triassic were key time intervals in the history of life on Earth. Both periods are marked by a series of biotic crises including the most catastrophic of such events, the end-Permian mass extinction, which eventually led to a major turnover from typical Palaeozoic faunas and floras to those that are emblematic for the Mesozoic and Cenozoic. Here we review patterns in Permian-Triassic bony fishes, a group whose evolutionary dynamics are understudied. Based on data from primary literature, we analyse changes in their taxonomic diversity and body size (as a proxy for trophic position) and explore their response to Permian-Triassic events. Diversity and body size are investigate…
Effects of lindane on fish carbohydrate metabolism.
1991
Exposure of the European eel (Anguilla anguilla) to a high sublethal concentration of 0.335 ppm (0.50 of the 96-hr LC50) of lindane for 6, 12, 24, 48, 72, and 96 hr affected carbohydrate metabolism. Muscle glycogen levels decreased significantly (P less than 0.05) at 6, 12, 24, 48, 72, and 96 hr; liver glycogen content did not decline at any time. Muscle glucose levels in fish were elevated at 6, 12, 24, 48, 72, and 96 hr but in liver, the levels increased only at 96 hr. Mean values of muscle and liver pyruvate were elevated significantly (P less than 0.05) at 6, 12, 24, 48, and 72 hr. Muscle lactate levels increased at 6, 12, 24, and 48 hr in pesticide-treated fish. Liver lactate levels we…
Susceptibility of eye fluke-infected fish to predation by bird hosts.
2005
Host manipulation by trophically transmitted parasites may predispose infected hosts to predation and in this way enhance parasite transmission. In most study systems, however, the evidence comes from laboratory studies, and therefore knowledge of the effect of manipulation on parasite transmission efficiency in the wild is still limited. Here we examined the effect ofDiplostomum spathaceum(Trematoda) eye flukes on the susceptibility of fish intermediate hosts to predation by bird definitive hosts. Our earlier studies have shown that the parasite alters fish phenotype and increases their susceptibility to artificial predation under laboratory conditions. In the present field study, we allow…
A catalogue of the vertebrate fossil record from the Guadix-Baza Basin (SE Spain)
2020
In this paper, a catalogue of the vertebrate content of the Guadix-Baza Basin is presented. A total of 93 localities have been reviewed, providing more than 300 vertebrate species. These localities have been included in 11 biochronological units, ranging in age from the late Miocene (MN 13) to the Middle Pleistocene (MmQ 4), including also two MN 10 localities. The best-represented epoch in the Guadix-Baza Basin is the Pliocene (MN 14 to MN 16), with 41 sites. This is followed by the Early Pleistocene (MN17 and MmQ1 to MmQ3) with 30 sites. The vertebrate classes represented in the basin are Actinopterygii, Amphibia, Aves, Reptilia and Mammalia, this last one being the best represented. Amon…
The effect of time on physiological changes in eel Anguilla anguilla, induced by lindane.
1991
Abstract 1. 1. Eel were exposed to a sublethal concentration of lindane (0.335 ppm) for 6, 12, 24, 48, 72 and 96 hr. 2. 2. Concentrations of glycogen, glucose, lactate, pyruvate and lipids were determined in gill tissue after lindane exposure. 3. 3. Gill glycogen descreased and glucose levels increased at 6 hr of treatment, lactate and pyruvate concentration increased between 6 and 48 hr. Total lipid values decreased between 6 and 24 hr; thereafter, the levels increased up to 72 hr of exposure. 4. 4. Clear changes were found in all parameters tested in gill tissues. The observed effects of lindane on metabolism in fish are discussed in relation to acute stress syndrome.
Testing Acute Toxicity in the Embryo of Zebrafish, Brachydanio rerio, as an Alternative to the Acute Fish Test: Preliminary Results
1994
Acute toxicity testing in fish is a standard method used in estimating the influences of chemicals on aquatic vertebrates. The ecotoxicological data obtained from acute toxicity tests in fish are, however, not sufficiently reliable to justify the continued use of this test. Fertilised eggs of zebrafish ( Brachydanio rerio) were used to test the acute toxicity of chemicals. They were chosen because the development of B. rerio has been studied extensively and information already exists concerning the normal development of this species. The following parameters of the development of B. rerio were observed: coagulation of the egg, gastrulation, number of somites, movement, development of organ…
δ18O values of coexisting brachiopods and fish: Temperature differences and estimates of paleo–water depths
1998
To estimate vertical thermal gradients and paleo–water depths to marine platforms we present a new method based on the difference between δ 18 O values of contemporaneous brachiopod carbonate and fish phosphate. Present-day marine fauna of well-known ecology from the surface to the sea floor record isotopic temperatures that agree with measured temperatures. We predict distributions of isotopic data that result from sampling strategy, basin morphology, and fauna ecology and discuss limitations. Application of the method to the Jurassic Paris-London basin gives vertical thermal variations of up to 14 °C associated with depths varying from a few meters to 170 ± 30 m. The estimated depths are …
Estimating the effects of winter-fishing: mobile echosounding under ice
1999
Abstract An echosounder with a tape recorder in a propeller-driven waterproof box (an echosounder shuttle) was used under the ice to monitor the vertical distribution and density of fish in a winter seining area of a Finnish lake in April 1997. The surveyed fish were at 3.5–8 m depth, and fish density was significantly lower after seining than before. The seine catch was about 10 kg ha−1, and the echosounding results showed a decrease of 7 kg ha−1 in the hauling area. There were some difficulties due to the low temperature, and minor problems with steering and leakage of the shuttle. We conclude that it is possible to make mobile echosurveys under the ice and estimate densities of wintering…
Experience and dominance in fish pairs jointly shape parasite avoidance behaviour
2018
There is increasing evidence that the composition of a social group influences the fitness of its members. For example, group member identities can determine the exposure risk to contact-transmitted parasites and consequently impact the health of all group members. Here, we propose that group composition may also affect host exposure to parasite propagules prevailing in the environment via collective parasite avoidance behaviours. We explored the spatial avoidance of a trematode parasite, Diplostomum pseudospathaceum, using the simplest form of host groups, pairs of sea trout, Salmo trutta trutta. These pairs showed either (1) between-group heterogeneity in their experience with the parasit…
Chemical characterization of organic residues on Late Roman amphorae from shipwrecks off the coast of Marsala (Trapani, Italy)
2021
Abstract Organic residues were extracted from thirty-three different types of Roman and Late Antique amphorae retrieved from underwater contexts in the custody of the Archaeological Museum “Baglio Anselmi” of Marsala in Sicily. The samples were analysed using GC-MS and 1H NMR, finding biomarkers of plant oils (including saturated and unsaturated fatty acids, alcohols and alkanes present in plant waxes) were identified in seven samples. The biomarkers for Pinaceae spp., used for making pitch, were identified in one sample. The results obtained shed light on the function of different types of North African amphorae, traditionally interpreted as containers for olive oil, wine and fish sauce, p…