| 1. |
- Goicoechea, Noemi, et al.
(författare)
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Recovering phylogenetic signal from frog mating calls
- 2010
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Ingår i: Zoologica Scripta. - : Wiley. - 0300-3256 .- 1463-6409. ; 39:2, s. 141-154
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Tidskriftsartikel (refereegranskat)abstract
- Few studies have tried to analyse the phylogenetic information contained in frog mating calls. While some of those studies suggest that sexual selection deletes any phylogenetic signal, others indicate that frog calls do retain phylogenetic informative characters. Discordant results can be the outcome of disparate rates of character evolution and evolutionary plasticity of call characters in different groups of frogs, but also the result of applying different coding methods. No study to date has compared the relative performance of different coding methods in detecting phylogenetic signal in calls, hampering thus potential consilience between previous results. In this study, we analyse the strength of phylogenetic signal in 10 mating call characters of 11 related species of frogs belonging to three genera of Andean and Amazonian frogs (Anura: Terrarana: Strabomantidae). We use six quantitative characters (number of notes per call, note length, call length, number of pulses per note, fundamental frequency and dominant frequency) and four qualitative ones (presence/absence of: pseudopulses, frequency modulation in notes, amplitude modulation in notes and amplitude modulation in pulses). We code quantitative characters using four different coding and scaling methods: (i) gap-coding, (ii) fixed-scale, (iii) step-matrix gap-weighting with between-characters scaling, and (iv) step-matrix gap-weighting with between-states scaling. All four coding methods indicate that frog calls contain phylogenetic information. These results suggest that divergent selection on frog mating calls may not always be strong enough to eliminate phylogenetic signal. However, coding methods strongly affect the amount of recoverable information. Step-matrix gap-weighting with between-characters scaling and gap-coding are suggested as the best methods available for coding quantitative characters of frog calls. Also, our results indicate that the arbitrariness in selecting character states and the method for scaling transitions weights, rather than the number of character states, is what potentially biases phylogenetic analyses with quantitative characters.
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| 2. |
- Koehler, Joern, et al.
(författare)
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Systematics of Andean gladiator frogs of the Hypsiboas pulchellus species group (Anura, Hylidae)
- 2010
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Ingår i: Zoologica Scripta. - : Wiley. - 0300-3256 .- 1463-6409. ; 39:6, s. 572-590
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Tidskriftsartikel (refereegranskat)abstract
- We revisit the taxonomic status of Andean species and populations of frogs of the Hypsiboas pulchellus group using multiple lines of evidence potentially indicative of evolutionary lineage divergence in anurans: differences in qualitative morphological or bioacoustic character states, no overlap in quantitative characters of advertisement calls, and monophyly of gene genealogies. We found qualitative and quantitative morphological characters to be extremely variable among species and populations of the group and thus of very limited use in assessing lineage divergence. In contrast, phylogenetic analyses based on 16S rRNA and cytochrome b sequences resolved highly supported clades that are in concordance with bioacoustic differences. The results support the specific distinctness of most nominal species recognized in the group, including the Bolivian Hypsiboas balzani and Hypsiboas callipleura, two species that were considered to be synonymous, and revealed the presence of an undescribed species from southern Peru, which is here described as Hypsiboas gladiator sp. n. In contrast, Hypsiboas andinus and Hypsiboas riojanus were mutually paraphyletic, and showed no differences in morphology and acoustic characters. Consequently, we regard the former as a junior synonym of the latter. However, we discovered that populations of H. riojanus from central Bolivia exhibit some degree of genetic differentiation and advertisement call differences with respect to Argentine populations, but sampling of these Bolivian populations is too sparse to draw taxonomic conclusions. Our phylogenetic results support the hypothesis that ancestral lineages of the Andean H. pulchellus group experienced successive splitting events along a latitudinal gradient from north to south.
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| 3. |
- Padial, José M., et al.
(författare)
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A response to recent proposals for integrative taxonomy
- 2010
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Ingår i: Biological Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4066 .- 1095-8312. ; 101:3, s. 747-756
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Tidskriftsartikel (refereegranskat)abstract
- Several proposals have been launched under the new concept 'integrative taxonomy' to frame the future development of species discovery and description. We consider that some of those proposals have failed to be truly integrative, by not acknowledging the limitations of operational definitions of species, by defending some kinds of evidence as universally superior, by considering taxonomy to be irreconcilable with population genetics, or by ignoring that the heterogeneity of evolutionary processes often precludes full character congruence in species. Here we defend a taxonomy where species exist, but not in any particular way everyone might want them to exist; a taxonomy open to data and methods from population biology, phylogeography and phylogenetics, as well as any other discipline providing evidence about the origin and evolution of species. This new taxonomy embraces all the consequences of considering species as lineages of reproductive populations, encouraging the use of as many lines of evidence as possible, but without negating that a single line may also be the only one providing evidence for a particular species. Species cannot only be those reproductive populations showing broad character congruence and/or reproductive isolation, due to the different degrees of character congruence, as well as of reproductive isolation, that result from the heterogeneity of evolutionary processes causing lineage splitting and divergence. Also, any kind of character - and not only those established by tradition or fashion - is potentially relevant as evidence of lineage divergence. To conciliate the authors who only see species supported by broad character congruence as good species hypotheses, we explain how a hypothesis can gain corroboration using single or multiple lines of evidence, even in cases of discordance with other lines of evidence. Finally, we propose guidelines to identify the expected degree of stability (preliminary, unstable, and stable) of species hypotheses. (C) 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101, 747-756.
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| 4. |
- Padial, José M., et al.
(författare)
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The integrative future of taxonomy
- 2010
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Ingår i: Frontiers in Zoology. - : Springer Science and Business Media LLC. - 1742-9994. ; 7, s. 16-
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Forskningsöversikt (refereegranskat)abstract
- Background: Taxonomy is the biological discipline that identifies, describes, classifies and names extant and extinct species and other taxa. Nowadays, species taxonomy is confronted with the challenge to fully incorporate new theory, methods and data from disciplines that study the origin, limits and evolution of species. Results: Integrative taxonomy has been proposed as a framework to bring together these conceptual and methodological developments. Here we review perspectives for an integrative taxonomy that directly bear on what species are, how they can be discovered, and how much diversity is on Earth. Conclusions: We conclude that taxonomy needs to be pluralistic to improve species discovery and description, and to develop novel protocols to produce the much-needed inventory of life in a reasonable time. To cope with the large number of candidate species revealed by molecular studies of eukaryotes, we propose a classification scheme for those units that will facilitate the subsequent assembly of data sets for the formal description of new species under the Linnaean system, and will ultimately integrate the activities of taxonomists and molecular biologists.
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