Musical calling as a behavior ancestral to all modern primates

Music is a singular behavior humans exhibit via the creation of patterned sounds organized, for example, along rhythmic and melodic dimensions. Music-like behavior, however, also appears in many other animals including non-human primates. Calls with western musical attributes are primarily ascribed to species of gibbon, tarsier, indri, and potentially also marmoset, tamarin, and titi monkeys. A recent survey of primates, using a continuous measure of acoustic musicality, suggests that many other species—including galagos, several lemurs, and some old-world monkeys—also exhibit calls with music-like qualities. Based on this ubiquity and a recent arboreal-origins theory for musical behavior, I hypothesized that the ancestor of all living primates was likewise also somewhat musical. Ancestral character estimation was used to reconstruct ancestral phylogenetic states using scored spectrographic depictions of vocalizations of extant primates (n=58 species) to determine if musical calling is the initial primate condition. The results suggest that nearly all primate families have an ancestor with at least one moderately music-like call—two or more reappearing syllables—with the clear exception of Cercopithecine. These cheek-pouch monkeys likely experienced a multi-million year diminution in musical behavior, perhaps in conjunction with their recent adaptations for quadrupedal terrestriality. These findings largely indicate that exhibition of at least one music-like call is a normal, and likely quite ancient, constituent of primate vocalization behavior.

­Comparative spigot ontogeny across the spider tree of life

Spiders are well known for their silk and its varying use across taxa. Very few studies have examined the silk spigot ontogeny of the entire spinning field of a spider. Historically the spider phylogeny was based on morphological data and behavioral data associated with silk. Recent phylogenomics studies have shifted major paradigms in our understanding of silk use evolution, reordering phylogenetic relationships that were once thought to be monophyletic. Considering this, we explored spigot ontogeny in 22 species, including Dolomedes tenebrosus and Hogna carolinensis, reported here for the first time. This is the first study of its kind and the first to incorporate the Araneae Tree of Life. After rigorous testing for phylogenetic signal and model fit, we performed 60 phylogenetic generalized least squares analyses on adult female and second instar spigot morphology. Six analyses had significant correlation coefficients, suggesting that instar, strategy, and spigot variety are good predictors of spigot number in spiders, after correcting for bias of shared evolutionary history. We performed ancestral character estimation of singular, fiber producing spigots on the posterior lateral spinneret whose potential homology has long been debated. We found that the ancestral root of our phylogram of 22 species, with the addition of five additional cribellate and ecribellate lineages, was more likely to have either none or a modified spigot rather than a pseudoflagelliform gland spigot or a flagelliform spigot. This spigot ontogeny approach is novel and we can build on our efforts from this study by growing the dataset to include deeper taxon sampling and working towards the capability to incorporate full ontogeny in the analysis.

El método compativo en ecología vegetal

In this paper a review of the uses of the comparative method in plant eco logy is presented. Particular attention is devoted to statistical methods that analyze variation in continuos phenotypic traits. The comparative method incorporates the phylogenetic relationships of the species in recognition that species usually do not provide independent points in statistical analysis because they share characteristics through descent from common ancestors. This review is divided in three sections. In the first one, the different statistical analysis that comprises the comparative method are presented, particular attention is devoted to: i] Evolutionary correlations, ii] phylogenetic inertia, and iii] ancestral character estimation. The second section presents the different papers that had applied these different methodologies, in both, origin al or reanalyzed data. Finally, in the third section the use of comparative methods to study adaptation and the debate between the use of phylogenetically based statistical methods and conventional statistical analyses are discussed.