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  • 1
    Publication Date: 2014-11-07
    Description: Spadefoot toads (Pelobates) and Parsley frogs (Pelodytes) are an enigmatic group of Western Palaearctic anurans. In the genus Pelobates, a fossorial lifestyle has enforced a conserved bauplan that masks their intraspecific evolutionary history. We used partial sequences of the mitochondrial 16S and 12S rRNA genes to infer a paleobiogeographic scenario of speciation events in these two anuran genera. Based on two alternative, mutually exclusive calibrations of the Iberian-African split within Pelobates (Pb. cultripes and Pb. varaldii), the disjunction of the Betic Cordillera ca. 14-16 million years ago (mya), and the end of the Messinian Salinity crisis 5.33 mya, we inferred alternative scenarios for species evolution within both genera applying regression-based dating and Bayesian molecular dating. Pelobates and Pelodytes are both monophyletic genera. Interspecific relationships among spadefoot toads are poorly resolved, and only an Iberian-African Pb. cultripes/Pb. varaldii clade consistently emerges from our analyses. An evolutionary scenario based on the Messinian divergence of African and Iberian Pelobates lineages becomes plausible in the light of geological and paleontological data. Consequently, Pelobates species are likely to have originated from the Miocene. Speciation around the Oligocene/Miocene boundary is inferred for the Iberian-Caucasian Pelodytes, and a Messinian divergence has to be invoked to explain intraspecific diversification of Iberian parsley frogs. There is indication that the different Pb. syriacus lineages may not form a monophylum.
    Keywords: Phylogeny ; paleobiogeography ; speciation ; regression-based molecular clock ; Bayesian molecular dating ; Messinian salinity crisis ; 16S ; 12S ; 42.82
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
    Format: application/pdf
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  • 2
    Publication Date: 2024-01-12
    Description: Spadefoot toads (Pelobates) and Parsley frogs (Pelodytes) are an enigmatic group of Western Palaearctic anurans. In the genus Pelobates, a fossorial lifestyle has enforced a conserved bauplan that masks their intraspecific evolutionary history. We used partial sequences of the mitochondrial 16S and 12S rRNA genes to infer a paleobiogeographic scenario of speciation events in these two anuran genera. Based on two alternative, mutually exclusive calibrations of the Iberian-African split within Pelobates (Pb. cultripes and Pb. varaldii), the disjunction of the Betic Cordillera ca. 14-16 million years ago (mya), and the end of the Messinian Salinity crisis 5.33 mya, we inferred alternative scenarios for species evolution within both genera applying regression-based dating and Bayesian molecular dating. Pelobates and Pelodytes are both monophyletic genera. Interspecific relationships among spadefoot toads are poorly resolved, and only an Iberian-African Pb. cultripes/Pb. varaldii clade consistently emerges from our analyses. An evolutionary scenario based on the Messinian divergence of African and Iberian Pelobates lineages becomes plausible in the light of geological and paleontological data. Consequently, Pelobates species are likely to have originated from the Miocene. Speciation around the Oligocene/Miocene boundary is inferred for the Iberian-Caucasian Pelodytes, and a Messinian divergence has to be invoked to explain intraspecific diversification of Iberian parsley frogs. There is indication that the different Pb. syriacus lineages may not form a monophylum.
    Keywords: Phylogeny ; paleobiogeography ; speciation ; regression-based molecular clock ; Bayesian molecular dating ; Messinian salinity crisis ; 16S ; 12S
    Repository Name: National Museum of Natural History, Netherlands
    Type: info:eu-repo/semantics/article
    Format: application/pdf
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  • 3
    ISSN: 0044-2313
    Keywords: 1,3-Di-tert-butyl-2,2-dimethyl-4-X-4-Y-1,3,2,4-diazasilagermetidines (X, Y = halide, pseudohalide, alkyl or amino substituent) ; syntheses ; reduction ; 1H-NMR ; X-ray structure analyses ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclic Diazastannylenes. XXXII. On the Synthesis and Reactivity of Difunctional Cyclosilagermadiazanes - Formation of DigermanesThe cyclic bisaminostannylene Me2Si(t-BuN)2Sn 1 reacts with tetrahalides of germanium GeX4(X = Cl, Br, I) forming the bisaminodihalogengermanes 2a, 2b and 2c. The halogen atoms of the compounds 2 may be substituted by alkyl-, amino- and pseudohalide groups: Me2Si(t-BuN)2GeXY (X = Y = N3 3; X = Br, Y = Me 4, Y = t-Bu 6, Y = N(SiMe3)2 8a, Y = NEt2 9; X = Me, Y = N3 5a, Y = CN 5b; X = N3, Y = t-Bu 7, Y = N(SiMe3)2 10; X = I, Y = N(SiMe3)2 8b). Reduction of the compounds 2b and 4 with sodium naphthalide generates the digermanes (Me2Si(t-BuN)2GeR)2 (with R = Br 11, R = Me 12) Compound 8b crystallizes in the monoclinic space group P21/c with Z = 8 and lattice constants a = 16.205(8), b = 19.854(9), c = 17.537(9) Å, β = 107.50(9)°. Compound 11 crystallizes in the triclinic space group P1 with Z = 2 and lattice constants a = 8.921(4), b = 11.091(5), c = 17.590(8) Å, α = 80.5(1), β = 89.2(1), γ = 71.4(1)°.
    Notes: Das cyclische Bisaminotannylen Me2Si(t-BuN)2Sn 1 reagiert mit Germaniumtetrahalogeniden GeX4 (X = Cl Br, I) zu den Bisaminodihalogengermanen 2a, 2b und 2c. Die Halogenatome der Verbindungen 2 können durch Alkyl- und Amino- sowie Pseudohalogengruppen ersetzt werden: Me2Si(t-BuN)2GeXY (X = Y = N3) 3; X = Br, Y = Me 4, Y = t-Bu 6, Y = N(SiMe3)2 8a, Y = NEt2 9; X = Me, Y = N3 5a, Y = CN 5b; X = N3, Y = t-Bu 7, Y = N(SiMe3)2 10; X = I, Y = N(SiMe3)2 (8b). Durch Reduktion der Verbindungen 2b und 4 mit Natriumnaphthalid erhält man die Digermane (Me2Si(t-BuN)2GeR)2 (mit R = Br 11, R = Me 12). Die Verbindung 8b kristallisiert in der monoklinen Raumgruppe P21/c mit Z = 8 und a = 16,205(8), b = 19,854(9), c = 17,537(9) Å, β = 107,50(9)° und die Verbindung 11 kristallisiert in der triklinen Raumgruppe P1 mit Z = 2 und den Gitterkonstanten a = 8,921(4), b = 11,091(5), c = 17,590(8) Å, α = 80,5(1), β = 89,2(1), γ = 71,4(1)°.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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