LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 2 of total 2

Search options

  1. Article ; Online: A review of age estimation methods in non-avian reptiles by growth marks in hard tissues.

    Székely, Diana / Stănescu, Florina / Székely, Paul / Telea, Alexandra E / Cogălniceanu, Dan

    Integrative zoology

    2024  

    Abstract: Age and growth-related data are basic biological parameters, essential in population ecology, evolution, and conservation biology. There is a growing body of published information on reptile demography derived from sclerochronology, a technique based on ... ...

    Abstract Age and growth-related data are basic biological parameters, essential in population ecology, evolution, and conservation biology. There is a growing body of published information on reptile demography derived from sclerochronology, a technique based on counting the growth layers deposited in bones (skeletochronology) and other hard body structures. Since the data are not always easily available, we compiled the existing published data, described the current status of knowledge, synthetized the conclusions of disparate studies, and identified patterns of research and information gaps, prioritizing the needs for future research. Our database includes the results of 468 published studies covering 236 reptile species from 41 families. These represent less than 2% of the total number of known extant species. Turtles and crocodiles are proportionally better studied, while snakes are the least examined group. The distribution of the research does not reflect conservation needs; we found an important geographic bias, with an overrepresentation of Northern temperate species. Only 23% of the studies checked the assumption of periodicity of growth marks deposition, and the method was found to be reliable or adequate in 79% of the cases. Overall, the data obtained through sclerochronology can be considered robust, especially if validation methods are employed, since the general goal is to characterize population parameters, trends, and dynamics, rather than determining the exact age of any specimen in particular.
    Language English
    Publishing date 2024-01-22
    Publishing country Australia
    Document type Journal Article ; Review
    ZDB-ID 2570656-1
    ISSN 1749-4877 ; 1749-4869
    ISSN (online) 1749-4877
    ISSN 1749-4869
    DOI 10.1111/1749-4877.12808
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  2. Article ; Online: Melanism in the grass snake Natrix natrix (Linnaeus, 1758) from the Danube Delta Biosphere Reserve, Romania

    Fănaru, Geanina / Telea, Alexandra E. / Gherghel, Iulian / Melenciuc, Raluca

    Herpetozoa. 2022 Dec. 21, v. 35 p.257-263

    2022  

    Abstract: AbstractAnimal colouration has a significant ecological role in defence, reproduction, and thermoregulation. In the case of melanism, it is a complex topic. Besides potential disadvantages such as higher risk of predation, melanistic ectotherms may have ...

    Abstract AbstractAnimal colouration has a significant ecological role in defence, reproduction, and thermoregulation. In the case of melanism, it is a complex topic. Besides potential disadvantages such as higher risk of predation, melanistic ectotherms may have certain physiological advantages such as more efficient thermoregulation in colder climates and thus, reduced basking time. The common grass snake (Natrix natrix) is a widespread species throughout Europe and Asia. It exhibits a wide range of colour polymorphisms, from olive to dark grey, even albinistic and melanistic. Between 2016 and 2021, we conducted fieldwork in the Danube Delta Biosphere Reserve (DDBR) with the aim to document the geographic range of melanistic grass snakes. We categorised the melanistic expressions of N. natrix individuals as melanotic, completely melanistic, and partially melanistic. Melanistic snakes were encountered in all six localities visited, suggesting that the occurrence of melanistic grass snakes in the DDBR is geographically widespread. We observed both juveniles (n=2) and adults (n=11) with melanism, suggesting that individuals are born melanistic. However, the proportion of melanistic individuals in the general population of N. natrix from the DDBR is unknown. Only at Histria locality we studied the proportion of melanism in the grass snake population and 6.3% of the snakes caught were melanistic. Body size comparisons are not statistically significant because of the low sample size. The N. natrix melanistic morph’s geographical distribution in the DDBR is most likely due to an interaction of climate and habitats, which offer a thermal advantage in the face of predation pressure.
    Keywords Natrix natrix ; body size ; climate ; color ; conservation areas ; ectothermy ; geographical distribution ; grasses ; melanosis ; olives ; predation ; reproduction ; risk ; river deltas ; sample size ; Asia ; Romania ; colour morphs ; ectotherms ; melanotic ; polymorphism
    Language English
    Dates of publication 2022-1221
    Size p. 257-263.
    Publishing place Pensoft Publishers
    Document type Article ; Online
    ZDB-ID 2474932-1
    ISSN 2682-955X
    ISSN 2682-955X
    DOI 10.3897/herpetozoa.35.e85310
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

To top