In: Mythos im Alltag – Alltag im Mythos
Author: J.W. Arntzen

Abstract

The Golden-striped salamander (Chioglossa lusitanica) from the Iberian peninsula is characterised by the possession of a long tail which it can shed (autotomy). The allometric relationship of tail length and body length is described for larvae, juveniles and adult males and females, using modal values extracted from a large data set. Tail length increases non-lineary with body length and in adults the tail frequently exceeds twice the length of the body (i.e. tail-index > 2). The frequency of observed autotomy ranges from 6% to 33%. Differences are observed in tail-index and autotomy rates between life stages and sexes; differences are also observed between temporal and spatial subgroups. It is concluded that tail-length is an important demographic character in C. lusitanica. Comparisons are made with some American plethodontid salamanders to which C. lusitanica shows a striking morphological similarity.

In: Amphibia-Reptilia
Author: J.W. Arntzen

Abstract

During 1977 and in October 1978 fieldwork was carried out on the Golden-striped Salamander (Chioglossa lusitanica) in the surroundings of Porto (Portugal). The occurrence of C. lusitanica appears to be limited to the northwestern part of the Iberian Peninsula; its distribution is well defined by the region with a precipitation of more than 1000 millimeters per annum and not exceeding 1500 meters altitude. Here it leads a nocturnal and secretive life along small streams in hilly and mountainous terrain. In autumn, the adults meet on their mating-sites, observations on the mating process conform with data already available. Oögenesis takes place in summer. A positive relation was found between the length of the female and its fecundity. C. lusitanica can autotomize its tail, which can regenerate completely. It was found that oögenesis proceeds at the expense of tail-regeneration. Egg-deposition takes place in September, October and November, the larvae hatch after six to nine weeks. Metamorphosis takes place from the beginning of summer onward. Some larvae postpone metamorphosis until next season, having spent two winters in the water. Adults spend the summer in hidden places and remain largely inactive. It was found that with the drying up of the brooks a part of some populations migrated to summer-refuges such as dams and deserted mine galleries, thereby sometimes covering long distances. These refuges may also serve as a place for copulation and for egg-deposition. Migration-patterns in the populations under study were markedly different, largely depending on the availability of resorts and summer-refuges. Juveniles lead a live less nocturnal than the adults. Furthermore they show a stronger tendency to stay close to the brook and to stay there in summer. The population-density along one of the brooks investigated was estimated at four to five adult specimens per section of one meter in length. Water withdrawal presents a serious danger to certain populations.

In: Amphibia-Reptilia
Author: J. W. ARNTZEN

The spatial and ecological characteristics of two hybrid zones of amphibians are described. In two species of fire-bellied toads (genus Bombina) in central Europe, the location of the hybrid zone between them is determined by the parameters altitude and relief. In western France, the distribution of two hybridizing species of newts (genus Triturus) is described by the parameters relief and forestation. The toads fit the gradient model of hybrid zone structure, whereas the newts fit the mosaic model of hybrid zone structure. However, when the spatial scale of observation is varied, the distinction between the models fades and a continuum might exist between them.

In: Israel Journal of Ecology and Evolution
Authors: Ferrand, Lima, and Arntzen

Abstract

We studied age structure and growth in two populations of the golden-striped salamander, Chioglossa lusitanica, in northern Portugal by cohort analysis and skeletochronology. Lines of Arrested Growth (LAG) deposited during the larval phase could be distinguished from LAG deposited after metamorphosis. One or two LAG were found in larvae, with counts corresponding to age in years as predicted from larval size distributions. Post-metamorphic modal age was 5 to 6 years and longevity was 8 years. Von Bertalanffy growth curves for males and females from both populations were different from one another. Sexual maturity was reached 4 to 5 years after metamorphosis and corresponded with a snout-vent length of 43-44 mm in both sexes. A tendency was observed for females to be older than males. Mature females were on average larger than mature males. Larval growth was higher in spring than in winter and differed between populations and years. The population in which larvae grew relatively slowly was characterized by large young adults and vice versa, perhaps reflecting contrasting aquatic and terrestrial feeding conditions. The knowledge here presented is important for the better understanding of the population dynamics and ecological and conservation requirements of the golden-striped salamander.

In: Amphibia-Reptilia
Authors: Ben Wielstra and Arntzen

Abstract

The group of crested newts distributed from the southern Balkans to the southern shore of the Caspian Sea, Triturus karelinii sensu lato, comprises two species, T. karelinii in the east and T. arntzeni in the west. Three hypotheses have been forwarded defining the range of T. arntzeni, namely from northern Serbia eastwards i) in to Thrace, ii) up to the Aegean-Black Sea waterway including the Bosporus, or iii) into western Anatolia. We study 130 newts from 22 populations across this area with a panel of 40 enzyme nuclear genes. A combined analysis with the computer programs Structure and NewHybrids reveals the existence of two groups with admixture at two localities. The 'western group' comprises all European populations and a population at the southern shore of the Sea of Marmara in Asiatic Turkey, whereas the 'eastern group' is found at the Sakarya river valley in northern Anatolia, Asiatic Turkey. The admixed populations are also located in northern Anatolia. An analysis with the computer program BAPS resolves six genetic clusters, of which three represent the 'western group' and the other three coincide with the 'eastern group' and the two admixed populations. These analyses indicate that the species transition from T. arntzeni to T. karelinii is not in Thrace but in northern Anatolia. The presence of 'western' T. arntzeni to the east of 'eastern' T. karelinii indicates that the species' contact zone has a convoluted shape. Moreover, the spatial distribution of diagnostic allozymes only roughly coincides with that of two deeply divergent mitochondrial DNA haplotypes. A more detailed survey on the crested newt distribution in Anatolia is required to elucidate the picture further.

In: Amphibia-Reptilia
Authors: Arntzen and Judit Vörös

Abstract

Nuclear genetic variation and population structure were assessed in 140 individuals from 16 populations across the range of the Danube crested newt (Triturus dobrogicus) using 40 enzyme loci. Intraspecific hybridization with other crested newt species (Triturus carnifex, T. cristatus, T. macedonicus and T. arntzeni) affected 33 individuals in 11 populations at the range edge and reduced operational sample size to 107 T. dobrogicus in 14 populations. Allele diversity was high, and we inferred a high level of gene flow among T. dobrogicus populations, possibly associated with flooding conditions and the relatively continous habitat along rivers. Triturus dobrogicus showed weak but significant genetic structure between tributaries of the three main river systems of Danube, Sava and Tisza. The highest genetic diversity was observed in the Sava drainage, suggesting that this area might have been a Pannonian refugium during the most recent glacial maximum. The relatively high level of genetic variation observed suggests that a genetic bottleneck during this period has not been extreme.

In: Amphibia-Reptilia
Authors: Arntzen and Kurtulus Olgun

Abstract

We studied the number of rib-bearing vertebrae, eight morphometric characters and 36 protein loci in three subspecies of the banded newt, Triturus vittatus from the Near and Middle East. The number of rib-bearing vertebrae ranged from 12 to 15. Modal count was 13 in T. v. cilicensis, T. v. vittatus and T. v. ophryticus in the western part of the range and 14 in the eastern part of the T. v. ophryticus range. Significant differences were found between groups (cilicensis plus vittatus, western ophryticus, eastern ophryticus). Significant differences in shape were observed comparing T. vittatus with T. karelinii and T. montandoni, but not among T. v. vittatus, T. v. cilicensis and T. v. ophryticus. Genetic differentiation within T. v. ophryticus reached DNei = 0.24, which was similar to the distance observed between T. v. vittatus and T. v. cilicensis (DNei = 0.18). The two groups clustered at DNei = 0.58. We discuss the question whether T. v. ophryticus should be raised to species level.

In: Amphibia-Reptilia