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    Body size, age and population structure of Triturus carnifex (Urodela: Salamandridae) in the context of facultative paedomorphosis
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    Abstract:
    Facultative paedomorphosis occurs rarely in the genus Triturus compared to other European newts such as Ichthyosaura alpestris and Lissotriton spp., with most of observation related to single or few individuals per site. In this paper we report about body size, age and population size of two populations of Triturus carnifex with paedomorphs. Since one of the populations consisted of approximately 25% of paedomorphs, this is the first study about a population of large-bodied newts with a conspicuous number of paedomorphic individuals. We found evidences for an ecological causation of paedomorphosis, as well as further support for two recent findings about paedomorphosis: the reduction of sexual size dimorphism and the female-biased sex-ratio within paedomorphs.
    Keywords:
    Neoteny
    Salamandridae
    Triturus
    Facultative
    Sexual dimorphism
    Heterochrony
    SUMMARY The authors provide a detailed description of the skull in neotenic Triturus vulgaris meridionalis (Boulenger) (Amphibia Caudata Salamandridae) and compare it with the morphology of normal adults. The finds are also compared with published data concerning other urodeles. Though some interesting differences are found between the skull of normal and neotenic individuals, these do not plead in favour of the general hypothesis that neoteny has had a general role in the evolution of urodeles. The authors suggest that at an early stage of urodele evolution, telescoping of developmental phases occurred as an adaptation to short seasons favourable to larval development. The cranial kinesis of Triturus vulgaris is described in detail and this supports the contention by IORDANSKY (1982), contrary to current belief, that cranial kinesis is widespread among urodeles. Some features of cranial changes at metamorphosis appear to be linked with functional requirements.
    Neoteny
    Salamandridae
    Triturus
    Morphology
    The skull of neotenic individuals of the Alpine Newt Triturus alpestris from the locality Drakolimni (Greece) is described on the basis of models made from magnified serial frontal sections. In order to recognize features associated with neoteny and paedomorphosis, the results were compared with normal development of contemporary Triturus and of other Caudata. The neotenic larvae from Greece correspond to advanced stages of metamorphosis in normal development of Triturus alpestris. Comparison with salamandrids from the Tertiary of Europe in which the hyobranchial skeleton was preserved, namely Brachycormus noachicus, Chelotriton paradoxus, and Palaeopleurodeles hauffi, revealed that both latter taxa were completely metamorphosed adults anatomically similar to their contemporary relatives Tylototriton, Echinotriton, and Pleurodeles, whereas Brachycormus, though apparently related to Chelotriton, was a neotenic amphibian. This is suggested by its incompletely metamorphosed but ossified hyobranchial skeleton. © 1996 Wiley-Liss, Inc.
    Neoteny
    Salamandridae
    Triturus
    Pleurodeles
    Heterochrony
    Triturus
    Heterochrony
    Salamandridae
    Rejuvenation
    Notophthalmus viridescens
    Neoteny
    Citations (0)
    Over the entire observation history (up to and including 2023), the great crested newt Triturus cristatus (Laurenti, 1768) was found in 39 localities within 12 out of 23 administrative districts of the Tula region, with 23 locations (59%) discovered in the last 4 years (2020–2023). The vast majority of the find points (92.3%) belong to the zones of coniferous-broadleaved and broadleaved forests. The species is less common in the forest-steppe zone, although in general its distribution here is insufficiently studied. In the Tula region, the great crested newt spends its aquatic phase of life predominantly in artificial water bodies (71.4% of 28 cases), which is associated with a shortage of natural stagnant and semi-flowing water bodies due to the region's location on the Central Russian Upland. The abundance of T. cristatus in the populations identified in recent years is extremely low (the number of adult individuals counted in a specific water body has never exceeded several dozen). The article discusses species-specific limiting factors, among which, in recent decades, the colonization of small water bodies in the Tula region by the amur sleeper Perccottus glenii Dybowski, 1877, has had a particularly strong influence on the distribution and abundance of the great crested newt.
    Salamandridae
    Triturus
    Facultative paedomorphosis occurs rarely in the genus Triturus compared to other European newts such as Ichthyosaura alpestris and Lissotriton spp., with most of observation related to single or few individuals per site. In this paper we report about body size, age and population size of two populations of Triturus carnifex with paedomorphs. Since one of the populations consisted of approximately 25% of paedomorphs, this is the first study about a population of large-bodied newts with a conspicuous number of paedomorphic individuals. We found evidences for an ecological causation of paedomorphosis, as well as further support for two recent findings about paedomorphosis: the reduction of sexual size dimorphism and the female-biased sex-ratio within paedomorphs.
    Neoteny
    Salamandridae
    Triturus
    Facultative
    Sexual dimorphism
    Heterochrony