Staatliches Naturhistorisches Museum Braunschweig

Braunschweig, Germany

Staatliches Naturhistorisches Museum Braunschweig

Braunschweig, Germany
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Zinenko O.,University of Kharkiv | Stumpel N.,Staatliches Naturhistorisches Museum Braunschweig | Mazanaeva L.,Dagestan State University | Bakiev A.,Russian Academy of Sciences | And 12 more authors.
Molecular Phylogenetics and Evolution | Year: 2015

The phylogeny and historical demography of small Eurasian vipers of the Vipera ursinii and V. renardi complexes were studied using mitochondrial DNA sequences analysed with Bayesian inference, Maximum Likelihood and Maximum Parsimony approaches, and mismatch distributions. Diversification in the group resulted from an initial dispersion in the later Pliocene - Pleistocene in two directions: north-westwards via the Balkans (V. ursinii complex) and north-eastwards from Asia Minor via the Caucasus (V. renardi complex). An independent, comparatively recent transition occurred from montane habitats to lowland grasslands in different mitochondrial lineages during the Late Pleistocene, when representatives of the both complexes had reached lowland steppes to the north. Effective population size showed clear signs of rapid growth in eastern V. renardi, triggered by colonization of vast lowland steppes, but in western V. ursinii complex grew during the Last Glaciation and experienced stabilization in Holocene. Expansion and population growth in lowland lineages of V. renardi was not strongly affected by Pleistocene climatic oscillations, when cold, dry conditions could have favoured species living in open grasslands. The high diversity of closely related haplotypes in the Caucasus and Tien-Shan could have resulted from repetitive expansion-constriction-isolation events in montane regions during Pleistocene climate fluctuations. The mitochondrial phylogeny pattern conflicts with the current taxonomy. © 2014 Elsevier Inc.

Witzmann F.,University of Rhode Island | Hampe O.,Leibniz Institute For Evolutions Und Biodiversitatsforschung | Rothschild B.M.,Carnegie Museum | Joger U.,Staatliches Naturhistorisches Museum Braunschweig | And 3 more authors.
Journal of Vertebrate Paleontology | Year: 2016

Several abnormal caudal vertebrae are described in an indeterminate sauropod specimen from ?Middle–Late Jurassic strata of Niger. The anterior and posterior articular surfaces of caudal vertebrae 7–11 exhibit erosive perforations (‘holes’) of the subchondral compact bone into the trabecular bone of the vertebral centrum. Additionally, the vertebral centra of caudal vertebrae 17 and 18 are fused and show a bulging mass of abnormal bone growth, most probably caused by infection. The erosive lesions of the anterior tail vertebrae closely resemble the morphological and radiological characteristics of Schmorl's nodes in humans and other mammals, in which the gel-like nucleus pulposus of the intervertebral discs penetrates through the endplate into the cancellous bone of the vertebral body and creates an erosive cavity of mushroom-like shape. The diagnosis of Schmorl's nodes in this sauropod, however, would be incompatible with the extant phylogenetic bracket and osteological correlates that suggest that dinosaurs had no intervertebral discs. Rather, they possessed synovial joints with a joint space filled with synovial fluid between adjacent vertebral centra. Therefore, the lesions can best be interpreted as subchondral cysts and as an analog of Schmorl's nodes in synovial joints. Similar to Schmorl's nodes, the regular pattern and location of the lesions suggest that the cysts were caused by axial stress. One may hypothesize that the fusion of caudals 17 and 18 led to altered mechanical loading that may have facilitated rupture of the articular cartilage and subchondral bone and forced synovial fluid into the spongiosa of the vertebral centra. Citation for this article: Witzmann, F., O. Hampe, B. M. Rothschild, U. Joger, R. Kosma, D. Schwarz, and P. Asbach. 2016. Subchondral cysts at synovial vertebral joints as analogies of Schmorl's nodes in a sauropod dinosaur from Niger. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2016.1080719. © 2016 by the Society of Vertebrate Paleontology

Schulte U.,Marienstrasse 42 | Alfermann D.,Arbeitsgemeinschaft Amphibien und Reptilienschutz in Hessen e.V. AGAR | Bohme W.,Zoologisches Forschungsmuseum Alexander Koenig Museumsmeile Bonn | Joger U.,Staatliches Naturhistorisches Museum Braunschweig | And 4 more authors.
Natur und Landschaft | Year: 2016

To assess the connectivity of the Western Green Lizard along the lower reaches of the Moselle river and to evaluate the origin of populations in Hesse, we used a combination of maternally inherited markers (mtDNA: cytb) and Mendelian markers (microsatellites). Our results demonstrate that the westernmost populations along the Moselle are connected and compose a management unit of high value. In contrast the gene flow towards populations at the estuary is interrupted. Estimated effective population sizes document that these remaining populations are small and highly endangered. The genetic analysis of populations in Hesse suggests that they stem from systematic introductions of L. bilineata from the Kaiserstuhl or the offspring of such introductions. Furthermore, individuals of the Eastern Green Lizard (L. viridis) have been introduced within a L. bilineata population at the Kaiserstuhl without indication of hybridisation. Likewise we found introductions of L. bilineata from Brittany at the Kaiserstuhl. Our results thus emphasise the high relevance of genetic assignments of populations for nature conservation and legislation. © 2016 W. Kohlhammer, Stuttgart.

Smid J.,National Museum | Smid J.,South African National Biodiversity Institute | Shobrak M.,Taif University | Wilms T.,Allwetterzoo Munster | And 2 more authors.
Organisms Diversity and Evolution | Year: 2016

In this study, we provide genetic, morphological, and geographical comparisons for 11 species of the southwestern Arabian radiation of Hemidactylus geckos, nine of which are endemic to the region. By using a coalescence-based species-tree reconstruction in combination with divergence time estimations and speciation probability testing, we show that most of the speciation events occurred in the Pliocene, which is more recent than previously thought based on calibrations of concatenated data sets. The current dating indicates that the changing climate at the beginning of the Pliocene, from hot and dry to cold and wet, is likely responsible for increased speciation in Hemidactylus. Analyses of geographic and altitudinal overlap of the species and their morphological differentiation show that most species do not occur in sympatry. Those that overlap geographically are usually differentiated by their altitudinal preference, head shape, body size, or their combination. Our results indicate that the topographically complex mountains of southwestern Arabia support a significant radiation of Hemidactylus geckos by allowing multiple allopatric speciation events to occur in a relatively small area. Consequently, we describe two new species endemic to the Asir Mountains of Saudi Arabia, H. alfarraji sp. n. and H. asirensis sp. n., and elevate two former subspecies of H. yerburii to a species level, H. montanus and H. pauciporosus. © 2016 Gesellschaft für Biologische Systematik

Zinenko O.,University of Kharkiv | Zinenko O.,Ohio State University | Sovic M.,Ohio State University | Joger U.,Staatliches Naturhistorisches Museum Braunschweig | Gibbs H.L.,Ohio State University
BMC Evolutionary Biology | Year: 2016

Background: Studying patterns of introgression can illuminate the role of hybridization in speciation, and help guide decisions relevant to the conservation of rare taxa. Vipera magnifica and Vipera orlovi are small vipers that have high conservation status due to their rarity and restricted distributions in an area of the Caucasus region where two other related species are present - V. kaznakovi and V. renardi. Despite numerous observations of hybridization between different species of small vipers, and the potential of a hybrid origin for V. magnifica and V. orlovi based on their distribution with respect to V. kaznakovi and V. renardi, hypotheses of a hybrid origin have not been formally tested. Here we generate genomic-scale data by performing next generation sequencing of double digest restriction-site associated DNA libraries, and use these multilocus data to test whether these two species are of hybrid origin. Results: We generated over nine hundred loci for 38 specimens of six taxa, and analysed the dataset using Bayesian clustering and multivariate methods, as well as Patterson D-statistics, which can distinguish between incomplete lineage sorting and introgression as explanations for shared polymorphism. The results demonstrate a pattern of historical admixture in the two purported hybrids that is consistent with past gene flow from V. renardi into V. kaznakovi. The average admixture proportion in individuals was low (6.39 %) in the case of V. magnifica, but was higher in V. orlovi (19.02 %). We also show that the specific individual samples used in D-statistic tests can have a significant impact on inferences regarding the magnitude of introgression, suggesting the importance of including multiple individuals in these analyses. Conclusions: Our results support the conclusion that both V. orlovi and V. magnifica had formed through a hybridization event between V. kaznakovi and V. renardi. Given a low proportion of admixture and absence of clear ecological and morphological differences V. magnifica should be treated as a marginal population of V. kaznakovi. Further studies that include analyses of ecological segregation of V. orlovi from parental taxa and search for evolutionary consequences of hybridisation would clarify if V. orlovi is a distinct hybrid species. Until this we recommend preserving the current taxonomy and protection status of V. orlovi. © 2016 Zinenko et al.

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