Triturus Carnifex

The Italian crested newt (''Triturus carnifex'') is a species of newt in the family Salamandridae.

Habitat

''Triturus carnifex'' is found in parts of the Balkans and Italy. It is an aquatic breeder that can spend up to four months in the water.(Arntzen, J.W., Themudo, G.E., Wielstra, B. 2007. The phylogeny of crested newts
(Triturus cristatus superspecies): nuclear and mitochondrial genetic characters suggest a hard polytomy, in line with the paleogeography of the centre of origin. Contributions to Zoology 76(4):261-278.) The location of the ponds where they breed affects the time when ''T. carnifex'' enters the water. ''T. carnifex'' prefers living in deep water since it is a nektonic species: it swims freely and is independent of currents. The absence of predatory fish may also explain why ''T. carnifex'' is inclined to ponds, rather than other larger bodies of water.

They typically prefer ponds in northern Europe, where temperatures are colder . Adult ''T. carnifex'' start to arrive between February and May, and leave between July and October.(Andreone, F., and Giacoma, C. 1989. Breeding Dynamics of Triturus Carnifex at a pond
in Northwestern Italy (Amphibia, Urodela, Salamandridae). Holarctic Ecology
12:219-223.) In warmer ponds, adult newts arrive within a month and leave during a two-week period in July. Andreone and Giacoma (1989) speculated that newt migration into the ponds increases after rainy days, since after rainfall, newt activity is not limited by humidity.

Higher altitudes, where temperatures begin to decrease, have a direct effect on the size of ''T. carnifex''.(Ficetola, G. F., et al. 2010. Ecogeographical variation of body size in the newt Triturus carnifex:
comparing the hypotheses using an information-theoretic approach. Global Ecology and Biogeography 19: 485-495.) Ficetola et al. (2010) discovered that living in colder temperatures resulted a body size increase in both male and female. Females in higher altitudes were found to be larger because they were carrying more oocytes and larger ovaries, which gave them a reproductive advantage over the smaller females. ''T. carnifex'' is poikilothermic and larger body sizes help to reduce heat fluctuations. Ficetola also found that fluctuations in body temperature of T. carnifex decreased when body size increased. An increase in body size also occurs where there is increased precipitation or nearby primary producers, due to the effect of increased resources on animals.

Human interference has dramatically changed the habitat of ''T. carnifex'' due to the expansion of industrial areas and urban centers.(Ficetola and Bernardi 2003) This results in a fragmentation of natural landscapes, which leads to selective extinction, genetic drift, and inbreeding from isolation. Introducing fish to isolated wetland habitats also leads to a decline of amphibians because of predation on newt larvae.

Physiology

Adult newts in the genus ''Triturus'' were found to breathe mainly via the skin but also through the lungs and the buccal cavity. Lung breathing is mainly used when there is a lack of oxygen in the water, or at high activity such as during courtship, breeding, or feeding.(Eddy, F. B., P. McDonald. 1978. Aquatic respiration of The Crested Newt Triturus Cristatus. Comparative Biochemical Physiology. 59: 85-88)

When ''T. carnifex'' newts are induced into anemia, they are able to respire without the need of blood cells.(Casale. G.P, Khairallah. E. A., Grasso. J. A. 1980. An Analysis of Hemoglobin Synthesis in Erythropoeitic Cells. Developmental Biology 80:107-119. ) Around two weeks after anemia is induced, the newts produces a mass of cells that helps to revitalize the already circulating red blood cell mass.

During winter months, prolactin is released into the circulatory system, which drives ''T. carnifex'' into the aquatic environment and reduces the active transport of sodium ions.Lodi, G., Biciotti, M., and Viotto, B. 1981. Cutaneous Osmoregualtion in Triturus cristatus carnifex (Laur.) (Urodela). General and Comparative Endocrinology 46: 452-457. This happens because there is more water readily available to the newt for uptake as compared to its terrestrial dwelling during the summer months. In the aquatic phase, ''T. carnifex'' has a reduced urine flow and glomerular filtration rate compared to the terrestrial phase.(G. Lodi, M. Biciotti. 1985. Osmoregulatory adaptation of renal function in the terrestrial and aquatic phase crested newt (Triturus cristatus carnifex Laur. Bolletino di Zoologia. 52(3-4): 243-245.) In summer, aldosterone creates an increase in enzymatic activity in ''T. carnifex'', which leads to a decrease in ion transport.(G. Lodi, B. Dore, P. Usai, M. Biciotti. 1995. Ion transport processes and alkaline phosphatase activity in the skin of the crested newt. Bolletino di Zoologia. 62(2): 137-146.)

Behaviour and ecology

To avoid competition with other co-occurring newts, ''T. carnifex'' tends to reproduce in the deeper parts of a pond and is more nocturnal.(Fasola, M., 1993. Resource partitioning by three species of newts during their aquatic phase. Ecography 16: 73-81.) Due to their larger size, they can prey on smaller species such as the palmate newt.(Buskirk, J. 2007. Body size, competitive interactions, and the local distribution of Triturus newts. Journal of Animal Ecology 76:559-567.)

Reproductive females of ''T. carnifex'' were shown to regulate their body temperature more precisely and prefer higher temperatures than non-reproductive females and males.(L. Gvozdik. 1995. Does reproduction influence temperature preference in newts. Canadian Journal of Zoology. 83(8): 1038-1044. doi: 10.1139/z05-096)

Sensitivity to pollutants

Cadmium, a released into the environment from industrial and consumer waste, has been shown to be detrimental to ''T. carnifex'' even at a concentrations below Italian and European thresholds, by disrupting the activity of the adrenal gland.(Gay, F., V. Laforgia, I. Caputo, C. Esposito, M. Lepretti, and A. Capaldo, “Chronic Exposure to Cadmium Disrupts the Adrenal Gland Activity of the Newt Triturus carnifex (Amphibia, Urodela),” BioMed Research International.) In experiments allowing Italian crested newts to be exposed to nonylphenol, an endocrine disruptor common in leakage from sewers, there was a decrease in corticosterone and aldosterone, hormones produced by the adrenal gland and important for stress response.(A. Capaldo, F. Gay, S. Valiante, M. DeFalco, R. Sciarrillo, M. Maddaloni, V. Laforgia. 2012. Endocrine-disrupting effects of nonylphenol in the newt, Triturus carnifex (Amphibia, Urodela). Comparative Biochemistry and Physiology. 155(2): 352-358. doi: 10.1016/j.cbpc.2011.10.004)

References

External links

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{{Taxonbar, from=Q660346

Triturus
Amphibians described in 1768
Amphibians of Europe
Taxonomy articles created by Polbot
Taxa named by Josephus Nicolaus Laurenti