Complete nucleotide sequence of the mitochondrial genome of a salamander, Mertensiella luschani
The complete nucleotide sequence (16,650 bp) of the mitochondrial genome of the salamander Mertensiella luschani (Caudata, Amphibia) was determined. This molecule conforms to the consensus vertebrate mitochondrial gene order. However, it is characterized by a long non-coding intervening sequence with two 124-bp repeats between the tRNA Thr and tRNA Pro genes. The new sequence data were used to reconstruct a phylogeny of jawed vertebrates. Phylogenetic analyses of all mitochondrial protein-coding genes at the amino acid level recovered a robust vertebrate tree in which lungfishes are the closest living relatives of tetrapods, salamanders and frogs are grouped together to the exclusion of cae…
Bestimmung des Cobalts (und Nickels) durch Adsorptionsvoltammetrie in Grundlösungen mit Triethanolamin und Dimethylglyoxim
Schwach alkalische Losungen von Triethanolamin und NH4C1 sind zur Bestimmung niedriger Co-Gehalte durch Adsorptionsvoltammetrie nach Dimethylglyoximzusatz geeignet. Die Bestimmungsgrenze liegt bei 0,05 ppb Co (Reproduzierbarkeit 3–5%). Ein 250facher Ni-Uberschus und ein 25 000facher Zn-Uberschus storen nicht. Das Verfahren kann zur Bestimmung des Co in biologischem Material (Pflanzenasche) verwendet werden.
Bestimmung von Cobalt und Nickel in einigen biologischen Matrices — Vergleich Chelat-Gas-Chromatographie und Adsorptions-Voltammetrie
Die Arbeitsbedingungen fur die Bestimmung von Cobalt und Nickel in Biomatrices durch Chelat-Gas-Chromatographie und Adsorptionsvoltammetrie werden angegeben. In der Adsorptionsvoltammetrie ist die Verwendung geeigneter, die Bestandteile der Aschen bindender Grundlosungen von besonderer Wichtigkeit. Die Trockenveraschung der Proben ist fur die Bestimmung der beiden Elemente in Biomatices geeignet. Die Richtigkeit beider Verfahren wird anhand der Analyse von zertifizierten Referenzproben gezeigt. Ergebnisse orientierender Versuche zur Bestimmung der Bindungsformen der beiden Elemente werden fur Trockenmilchpulver mitgeteilt.
Exploring the potential of life-history key innovation: brook breeding in the radiation of the Malagasy treefrog genus Boophis
The treefrog genus Boophis is one of the most species-rich endemic amphibian groups of Madagascar. It consists of species specialized to breeding in brooks (48 species) and ponds (10 species). We reconstructed the phylogeny of Boophis using 16S ribosomal DNA sequences (558 bp) from 27 species. Brook-breeders were monophyletic and probably derived from an ancestral pond-breeding lineage. Pond-breeders were paraphyletic. The disparity in diversification among pond-breeders and brook-breeders was notable among endemic Malagasy frogs, although it was not significant when considering Boophis alone. Sibling species which have different advertisement calls but are virtually indistinguishable by mo…
Fluorescence labelling of organic acidic compounds with 4-bromomethyl-7-methoxycoumarin (Br-Mmc)
4-Bromomethyl-7-methoxycoumarin (Br-Mmc) is introduced as a fluorescence marker for aromatic and heterocyclic acids. To investigate the applicability of this method on substances of different chemical classes, screening experiments with 110 compounds were carried out using a microrefluxer. Most aromatic and heterocyclic monocarboxylic acids gave Mmc-esters which are fluorescent on thin-layer plates, like the Mmc-esters of fatty acids, which have been previously investigated. Strong acids, alcohols, amides and most amines did not react, whereas certain cyclic amines such as piperidine gave strongly fluorescent derivatives. Mmc-phenyl ethers shows only weak fluorescence. A new standard proced…
A molecular phylogeny of ‘true’ salamanders (family Salamandridae) and the evolution of terrestriality of reproductive modes
Key innovations enable species to conquer new habitats. Within the family Salamandridae, particular adaptations to terrestrial life, such as the anatomy and physiology of the feeding apparatus, courtship behaviour and in some cases viviparity, allowed the ‘true’salamanders (genera Chioglossa, Mertensiella, Salamandra) to shift from a semi-aquatic to a more terrestrial life cycle. We sequenced 423 base pairs of the 16S RNA gene of the mitochondrial DNA for all species of the ‘true’salamanders. Based on the resulting phylogeny we discuss the evolution of terrestrial reproductive modes within this species group. We especially tested two hypotheses of monophyletic origin of specific adaptations…
Multiple overseas dispersal in amphibians
Amphibians are thought to be unable to disperse over ocean barriers because they do not tolerate the osmotic stress of salt water. Their distribution patterns have therefore generally been explained by vicariance biogeography. Here, we present compelling evidence for overseas dispersal of frogs in the Indian Ocean region based on the discovery of two endemic species on Mayotte. This island belongs to the Comoro archipelago, which is entirely volcanic and surrounded by sea depths of more than 3500 m. This constitutes the first observation of endemic amphibians on oceanic islands that did not have any past physical contact to other land masses. The two species of frogs had previously been tho…