Body Mass Shapes Most Life History Traits and a Fast-Slow Continuum in Amphibians.

Amphibians have the least studied life histories among vertebrates, although they have unique and the most diverse life histories within this group. We compiled a new dataset on adult body mass and 16 other life history traits of 2069 amphibian species across three orders (1796 frogs, 236 salamanders, 37 caecilians). These traits characterise fecundity, offspring development from egg deposition to metamorphosis and adult life. We established allometric models on traits for all amphibians and each of the three orders to assess a potential scaling of traits to body mass and then checked whether allometric slopes were consistent with two different metabolic scaling exponents. Further, we examined a possible fast-slow continuum in all amphibians, as well as in each of the two orders frogs and salamanders by applying principal component analysis (PCA) to five traits. Our allometric models indicated a positive scaling to body mass for 11 traits across all amphibians, 12 in frogs, and 10 in salamanders, and for five out of eight traits analysed in caecilians. Allometric slopes on most traits characterising offspring development were not significant. All slopes did not support a three-quarter metabolic scaling exponent, whereas slopes on age at maturity and maximum longevity were consistent with an amphibian metabolic scaling exponent of 0.88. As in fishes, reptiles, birds, and mammals, the first axes of our PCAs indicated a body mass-dependent fast-slow continuum in amphibians. Amphibian species of slow life histories have larger body masses, later sexual maturities and longer lifespans and lay more and larger eggs than species of fast life histories, a pattern also known from reptiles. The second axes indicated a trade-off between egg size and number. As this trade-off was nearly independent of body mass, we hypothesise that amphibians have occupied a broad range of ecological niches without evolutionary changes in body mass.

Ant-following behavior is correlated with plumage traits in African understory birds.

Ant-following behavior is a common phenomenon in birds of Neotropical and Afrotropical rainforests but yet little is known from Central Africa. We here report on the phenomenon in lowland rainforest in Cameroon, quantifying the strength of the interaction of different ant-following bird species with driver ants and test the hypothesis that higher levels of specialization in ant-following behavior are associated with dominance or aggression-dependent plumage and other morphological traits. Flock size varied between 1 and 11 individuals with a mean size of 5.34 ± 2.68 (mean ± SD) individuals occurring at the same time. The maximum number of species present during one raid observed was ten, whereas the minimum number was four with an overall species richness of 6.89 ± 2.1 species. The 21 attending bird species strongly varied in the degree of ant-following behavior. In an interspecific comparison, plumage traits such as the presence of a colored crown, eyespots, and bare skin around the eye, in combination with metatarsus length and weight, were significantly correlated with ant-following behavior. These results suggest that-in size and identity of species-ant-following bird assemblages in Central Africa are similar to those reported from East Africa. They also suggest that ant following favors the selection of traits that signal dominance in interactions between individuals struggling for valuable food resources in the forest understory.

Another piece for the syllid puzzle: A new species from Japan and its mitochondrial genome reveal the enigmatic Clavisyllis (Phyllodocida: Syllidae) as a member of Eusyllinae.

The phylogenetic relationships of Syllidae have been analyzed in several studies during the last decades, resulting in highly congruent topologies. Most of the subfamilies were found to be monophyletic, while other groups (Eusyllinae and several genera) have been reorganized attending their phylogenetic relationships. However, there are still several enigmatic genera, which could not be assigned to any of the established subgroups. These enigmatic genera usually show a combination of characters indicating relationships with several different groups, and some show morphological traits unique to Syllidae. One of the most intriguing genera, still unclassified within Syllidae is Clavisyllis Knox. Herein, we provide a complete description of a new species Clavisyllis tenjini n. sp. from Japan. We sequence the complete mitochondrial genome, compare with the available data from other syllids, and perform a phylogenetic analysis of three genes (18S, 16S, COI), traditionally used in previous studies. Clavisyllis shows a unique combination of characters within Syllidae, such as nuchal lappets and large ovoid dorsal cirri. The new species has additional anterior appendages that have not been found in any other syllid. Our results show the genus is a member of Eusyllinae, closely related to Pionosyllis Malmgren. The mitochondrial gene order agrees with the considered plesiomorphic gene order in Annelida, which is present in all members of Eusyllinae investigated so far. Clavisyllis reproduces by epigamy, the reproductive mode of members of Eusyllinae. The present study contributes to the systematics of Syllidae, a complex group with a large number of species and striking reproductive modes.

First mitochondrial genomes of Chrysopetalidae (Annelida) from shallow-water and deep-sea chemosynthetic environments.

Among Annelida, Chrysopetalidae is an ecologically and morphologically diverse group, which includes shallow-water, deep-sea, free-living, and symbiotic species. Here, the four first mitochondrial genomes of this group are presented and described. One of the free-living shallow-water species Chrysopetalum debile (Chrysopetalinae), one of the yet undescribed free-living deep-sea species Boudemos sp., and those of the two deep-sea bivalve endosymbionts Craseoschema thyasiricola and Iheyomytilidicola lauensis (Calamyzinae). An updated phylogeny of Chrysopetalidae is performed, which supports previous phylogenetic hypotheses within Chrysopetalinae and indicates a complex ecological evolution within Calamyzinae. Additionally, analyses of natural selection pressure in the four mitochondrial genomes and additional genes from the two shallow-water species Bhawania goodei and Arichlidon gathofi were performed. Relaxed selection pressure in the mitochondrion of deep-sea and symbiotic species was found, with many sites under selection identified in the COX3 gene of deep-sea species.