44 research outputs found

    Citizen Science, taxonomy and grass snakes: iNaturalist helps to clarify variation of coloration and pattern in Natrix natrix subspecies

    Get PDF
    Abstract We used a dataset of georeferenced photos of 5,751 grass snakes from iNaturalist to evaluate subspecific variation of Natrix natrix in coloration and pattern. Our results provide evidence that all four genetically delineated subspecies differ morphologically, although unstriped individuals of N. n. vulgaris are difficult to tell apart from the nominotypical subspecies. The iNaturalist dataset shows that the frequency of dark body coloration increases from south to north and from west to east. This trend is both concordant with taxonomic variation (the easternmost subspecies, N. n. scutata, being the darkest taxon) and variation within the same subspecies (in N. n. natrix and N. n. scutata more northern populations harbor more dark or melanistic individuals than more southern populations). Although available characters were limited to coloration and pattern traits, our study suggests that photo material from iNaturalist and similar platforms can be a valuable data source for studies on morphological variation. However, investigations using such databases can only supplement, but not replace, studies using museum material because only then measureable, meristic and genetic characters will be accessible

    Skeletal repatterning enhances the protective capacity of the shell in African hinge‐back tortoises (Kinixys)

    Get PDF
    Changes in the structural association of skeletal traits are crucial to the evolution of novel forms and functions. In vertebrates, such rearrangements often occur gradually and may precede or coincide with the functional activation of skeletal traits. To illustrate this process, we examined the ontogeny of African hinge-back tortoises (Kinixys spp.). Kinixys species feature a moveable “hinge” on the dorsal shell (carapace) that enables shell closure (kinesis) when the hind limbs are withdrawn. This hinge, however, is absent in juveniles. Herein, we describe how this unusual phenotype arises via alterations in the tissue configuration and shape of the carapace. The ontogenetic repatterning of osseous and keratinous tissue coincided with shifts in morphological integration and the establishment of anterior (static) and posterior (kinetic) carapacial modules. Based on ex vivo skeletal movement and raw anatomy, we propose that Kinixys employs a “sliding hinge” shell-closing system that overcomes thoracic rigidity and enhances the protective capacity of the carapace. Universal properties of the vertebrate skeleton, such as plasticity, modularity, and secondary maturation processes, contributed to adaptive evolutionary change in Kinixys. We discuss a hypothetical model to explain the delayed emergence of skeletal traits and its relevance to the origins of novel form-to-function relationships.info:eu-repo/semantics/publishedVersio

    Tortoise forensics: Conservation genetics of the leopard tortoise Stigmochelys pardalis in Southern Africa

    Get PDF
    Sub-Saharan Africa harbours an outstanding diversity of tortoises of which the leopard tortoise Stigmochelys pardalis is the most widespread. Across its’ range the species is impacted by habitat transformation, over-collection for human consumption and the pet trade, road mortality, and electrocution by electric fences. Most leopard tortoises in southern Africa are nowadays restricted to reserves and private farms. So far confiscated tortoises are frequently released into a nearby reserve without knowledge on their area of origin. This is problematic, as it has been demonstrated that the leopard tortoise harbours five distinct mitochondrial lineages, of which three occur in the southern portion of the species’ distributional range (South Africa, Namibia, and Botswana). Using 14 microsatellite loci corresponding to 270 samples collected throughout southern Africa, we found a clear substructuring in the north constituting four clusters (western, central, north-eastern, and eastern). Genetic diversity was particularly high in the north-east and decreased towards the south. In addition, we found a significant size difference between the studied populations. Our basic morphological analysis showed that tortoises from the southern cluster tend to grow bigger than tortoises from the north. We established a comprehensive genetic database for South Africa and Namibia that can serve as a conservation management tool for the assignment and potential release of translocated or seized leopard tortoises based on genetic affiliation

    Niche divergence corresponds to genetic differentiation within the parrot-beaked tortoise Homopus areolatus (Reptilia: Testudinidae), endemic to South Africa

    Get PDF
    We assessed genetic differentiation and habitat suitability for Homopus areolatus during current and Last Glacial Maximum (LGM) conditions. The ND4 locus retrieved two monophyletic mtDNA clades with lower diversity in clade 1, in the west, than in clade 2, in the south-east. Clade 1 showed a north–south and clade 2 a west-to-east genetic divergence, and the clades co-occur in the syntaxis zone of the Cape Fold Mountains. The clades occupy distinct niches with limited overlap. Rainfall seasonality contributed most to habitat suitability, with clade 1 being restricted to winter rainfall and clade 2 to all-year rainfall regions. Precipitation variables contributed 90% and 60%, respectively, to habitat suitability of clades 1 and 2, with temperature, particularly mean temperature of the driest quarter, being= of greater importance for clade 2 than clade 1. Suitable habitat shrank from the LGM to current conditions, probably due to reduced rainfall in the west and higher temperatures in most regions. We conclude that patterns of genetic divergence are strongly associated with ecological niche divergence of H. areolatus clades. More studies are needed to assess the taxonomic status of clade 1, particularly in view of its shrinking habitat due to climate change and anthropogenic factors

    Phylogeny and phylogeography of chelonians from sub-Saharan Africa—A review of current knowledge in tribute to Margaretha D. Hofmeyr

    Get PDF
    Species-level phylogeny and especially phylogeography of African chelonians is a comparatively under-studied field of research. We review the current knowledge of phylogeny and phylogeography, highlight congruence of spatial phylogeographic patterns amongst chelonians and other taxa and suggest future research directions to address gaps in knowledge. Our review shows that phylogeographic and phylogenetic investigations have led to unexpected findings. For example, for Pelomedusa, a putatively wide-ranging monotypic terrapin genus, cryptic diversity was revealed, with more than ten species being uncovered. The formerly recognized tortoise genus Homopus sensu lato was found to be paraphyletic with respect to Chersina. To resolve this situation, Homopus was restricted to the four-toed species H. areolatus and H. femoralis and the genus Chersobius was resurrected for the five-toed species C. boulengeri, C. signatus, and C. solus. Three previously recognized taxa were shown to be invalid, viz. the putatively extinct terrapin species Pelusios seychellensis and the tortoise subspecies Chersobius signatus cafer and Stigmochelys pardalis babcocki. Together with taxonomy, the knowledge of phylogeographic structuring sets a solid foundation for conservation measures and allows the identification of Management and Conservation Units. However, the current legislation, in particular the enforcement of the Nagoya Protocol under the Convention of Biological Diversity (CBD), has largely halted research on widely distributed taxa and turned the well-intended concept of Access and Benefit Sharing into a major impediment for conservation and research. The current situation leads for many species to a continued usage of outdated and incorrect taxonomic classifications resulting in an error cascade of conservation decisions. This is counterproductive to the aims of the CBD, that is, the protection of biodiversity. Sequencing historical DNA from museum specimens using aDNA approaches could be a short-term approach to mitigate, but not solve, this impediment

    Phylogeny of the Eurasian Wren Nannus troglodytes (Aves: Passeriformes: Troglodytidae) reveals deep and complex diversification patterns of Ibero-Maghrebian and Cyrenaican populations

    Get PDF
    Acknowledgments We are indebted to S. Birks (Burke Museum of Natural History and Culture, Seattle, WA, USA) and to J.-M. Pons (L’Institut de Systématique, Évolution, Biodiversité, Muséum national d’histoire naturelle, Paris, France), who kindly provided access to genetic material from their collections. We also thank G. López and CHAGRA ringing group for providing samples. All genetic analyses were performed at SGN-SNSD-Mol-Lab and we are grateful to A. Rauh, C. Spitzweg, A. Müller, and C. Kehlmaier for practical help in the molecular lab facilities. We would also like to thank M. Vamberger for support in phylogenetic analyses. Finally, we would like to thank four anonymous reviewers for constructive criticism on the manuscript. Erratum: Phylogeny of the Eurasian Wren Nannus troglodytes (Aves: Passeriformes: Troglodytidae) reveals deep and complex diversification patterns of Ibero-Maghrebian and Cyrenaican populations (PLoS ONE) (2020) 15: 3 (e0230151) DOI: 10.1371/journal.pone.0230151) F. Albrecht, J. Hering, E. Fuchs, J.C. Illera, F. Ihlow, T.J. Shannon, 2020. PLoS ONEPeer reviewedPublisher PD

    Ancient DNA elucidates the lost world of western Indian Ocean giant tortoises and reveals a new extinct species from Madagascar

    Get PDF
    © 2023 The Authors. Published by the American Association for the Advancement of Science under a Creative Commons License. The published version can be accessed at the following link on the publisher’s website: https://www.science.org/doi/10.1126/sciadv.abq2574Before humans arrived, giant tortoises occurred on many western Indian Ocean islands. We combined ancient DNA, phylogenetic, ancestral range, and molecular clock analyses with radiocarbon and paleogeographic evidence to decipher their diversity and biogeography. Using a mitogenomic time tree, we propose that the ancestor of the extinct Mascarene tortoises spread from Africa in the Eocene to now-sunken islands northeast of Madagascar. From these islands, the Mascarenes were repeatedly colonized. Another out-of-Africa dispersal (latest Eocene/Oligocene) produced on Madagascar giant, large, and small tortoise species. Two giant and one large species disappeared c. 1000 to 600 years ago, the latter described here as new to science using nuclear and mitochondrial DNA. From Madagascar, the Granitic Seychelles were colonized (Early Pliocene) and from there, repeatedly Aldabra (Late Pleistocene). The Granitic Seychelles populations were eradicated and later reintroduced from Aldabra. Our results underline that integrating ancient DNA data into a multi-evidence framework substantially enhances the knowledge of the past diversity of island faunas.The work of C.K. and U.F. was supported by the Senckenberg Society for Nature Research (SGN), Germany. The work of E.G. and U.F. was partially supported by the Spanish Ministry of Science and Innovation through the project PID2019-105682RA-100/AEI/10.13039/501100011033. The work of V.D. was supported by the Alexander von Humboldt Foundation, Germany. F.I. was supported by the German Research Foundation (DFG, grant number IH 133/1-1).Published versio

    Potential distribution and effectiveness of the protected area network for the crocodile lizard, Shinisaurus crocodilurus (Reptilia: Squamata: Sauria)

    No full text
    The crocodile lizard, Shinisaurus crocodilurus AHL, 1930, is a monotypic taxon, restricted in occurrence to southern China and northern Vietnam. Wild populations are presently suffering tremendous declines, mainly due to illegal poaching, habitat destruction, and fragmentation, which already led to the extinction of populations in Guangxi and Hunan provinces in China. In order to accelerate the discovery of so far unknown populations of S. crocodilurus and to identify suitable priority areas for conservation strategies, we determined the species' potential distribution using correlative species distribution models (SDMs) based on locality records and a set of satellite-based environmental predictors. In addition, we evaluated the coverage of the species' potential distribution with designated protected areas according to IUCN standards. The resulting SDM revealed potentially suitable habitats to be scattered and disconnected while being very small in size. Moreover, present coverage with nature reserves is extremely poor, underlining the urgent need for improved habitat protection measures and potential population restoration of S. crocodilurus
    corecore