Notes on Dacryodes Vahl, including a new species from the Rio Negro basin in Amazonia. Studies in neotropical Burseraceae. XI

Dacryodes is a poorly known pantropical genus of some 67 species; a new revision now under way reveals that the Neotropical region is home to at least 36 species, 14 of them undescribed. The genus is introduced with a brief taxonomic history, a presentation of the putative differences fromPseudodacryodes, a discussion of the infrageneric classification, and a preliminary comparison of Neo- and Paleotropical taxa. Characteristics that make the genus difficult to study are pointed out.Dacryodes negrensis, the first in a series of new taxa, is described and illustrated.     

Notes on the breeding biology of Rufous Potoos (Nyctibius bracteatus) in lowland Ecuadorian Amazon

Five species of potoos occur in Ecuador, with Rufous Potoos (Nyctibius bracteatus) being one of the least known. We monitored a nest site of Rufous Potoos in a lowland forest in the Ecuadorian Amazon and provide information about the behavior of a nestling and one or more adults. Observations were conducted opportunistically from 10 August to 10 September 2018, and an infrared heat‐and‐motion activated camera was used to monitor the nest site from 11 September to 13 November 2018. We recorded 2006 10‐s videos of the nestling and/or adult(s) that we used to quantify behavior. The nestling spent most of its time perching (53%) and stretching (20.7%). Beginning when ~ 23 d old, the nestling began exercising its flight muscles and did so with increasing frequency over time. Adult behaviors included perching while brooding the nestling (55%), stretching (24%), flying (10.4%), and feeding the nestling (10.4%). The duration of the nestling period, ~ 2 mo, in our study was similar to that reported previously for this species. Our observations suggest that the breeding and nestling behavior of Rufous Potoos is similar to that of other Nyctibius species. However, additional studies are needed to better document the behavior of Rufous Potoos during the incubation period.     

On the congruence of morphology,trophic ecology,and phylogeny in Neotropical treeboas (Squamata: Boidae: Corallus)

Nine members of the Neotropical treeboa genus Corallus occur from Guatemala to south‐eastern Brazil and recent studies have provided an inconclusive picture about the relationship between morphology and trophic ecology in these snakes. To construct a more complete picture, we conducted the first study of morphology and diet to consider all nine species. Using adult specimens from museum collections, we examined several morphometric and meristic variables and their possible relationship to Corallus diets. Broadly, we found three basic morphologies within the genus: a short, narrow head and a slender body (C. cookii, C. grenadensis, C. hortulanus, and C. ruschenbergerii), useful for exploiting a wide variety of prey; a relatively stout body with a long, wide head (C. batesii, C. caninus, and C. cropanii) associated with feeding on larger mammalian prey; and an intermediate morphology, found in C. annulatus and C. blombergii, which may be indicative of endotherm generalists. These morphological and dietary patterns exhibit a strong degree of congruence with a recent molecular phylogeny of Corallus and highlight a heretofore unexamined ecological diversification within Corallus. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109, 466–475.     

Extremely high variability in the S72 intron of the Amazonian cardinal tetra (Paracheirodon axelrodi)

Here, a combination of a DNA screening technique, direct sequencing and cloning was used to carry out a large-scale assessment of intron variability in cardinal tetras – the first to be conducted for an Amazonian forest fish. To the best of the authors' knowledge, the levels of DNA variability reported in this study are the highest ever documented for an intron marker.     

Phylogeny and comparative phylogeography of Sclerurus (Aves: Furnariidae) reveal constant and cryptic diversification in an old radiation of rain forest understorey specialists

Aim To evaluate the role of historical processes in the evolution of Sclerurus leaftossers by integrating phylogenetic and phylogeographical approaches. Location Humid forests of the Neotropical region. Methods We reconstructed the evolutionary history of Sclerurus based on DNA sequences representing all species and 20 of the 26 recognized subspecies using one autosomal nuclear locus and three protein‐coding mitochondrial gene sequences. Phylogenetic relationships were inferred using Bayesian and maximum‐likelihood methods. We used Bayesian coalescent‐based approaches to evaluate demographic changes through time, and to estimate the timing of diversification events. Based on these results, we examined the temporal accumulation of divergence events using lineage‐through‐time plots. Results The monophyly of all Sclerurus species was strongly supported except for Sclerurus mexicanus, which was paraphyletic in relation to Sclerurus rufigularis, and for the sister pair Sclerurus scansor–Sclerurus albigularis, which were not reciprocally monophyletic in the nuclear tree. We found remarkably deep phylogeographical structure within all Sclerurus species, and overall this structure was congruent with currently recognized subspecies and Neotropical areas of endemism. Diversification within Sclerurus has occurred at a relatively constant rate since the Middle Miocene. Main conclusions Our results strongly support the relevance of physiographical (e.g. Nicaragua Depression, Isthmus of Panama, Andean Cordillera, great rivers of Amazonia) and ecological barriers (open vegetation corridor) and ecological gradients (elevational zonation) to the diversification of Neotropical forest‐dwelling organisms. Despite the high congruence among the spatial patterns identified, the variance in divergence times suggests multiple speciation events occurring independently across the same barrier, and a role for dispersal. The phylogenetic patterns and cryptic diversity uncovered in this study demonstrate that the current taxonomy of Sclerurus underestimates the number of species.     

Labile Phosphorus in Soils of Forest Fallows and Primary Forest in the Bragantina Region, Brazil

We used the Hedley sequential extraction procedure to measure nine different organic inorganic soil phosphorus fractions in forest soil of the Bragantina region of Para, Brazil. We compared the labile fractions (resin‐extractable P + HCO3‐extractable inorganic and organic P) in Oxisols from three secondary forests (10, 20, and 40 years old) and a primary forest. These stands were located in an area that has supported shifting agriculture for approximately a century. After agricultural use, total P and labile P in soils of young secondary forests are diminished compared to the amounts presents in the primary forest soil. Within each stand, organic carbon content was a good predictor of labile organic and inorganic P, consistent with the large body of research indicating that mineralization of organic matter is important to plant nutrition in tropical ecosystems. During the reorganization of P pools during forest development, the pool of labile organic P (HCO3‐extractable) diminishes more than the other labile fractions, suggesting that it is directly or indirectly an important source of P for the regrowing forest vegetation. Across the four age classes of forest, the soil reservoir of labile P was equal to or greater than the total amount of P in the vegetation. If labile P measured by this method adequately represents P available to plants in the short term (as suggested by the current consensus), we would conclude that plant‐available P is reasonable abundant, and that the effects of agriculture on available P pools are detectable but not sufficient to compromise forest regrowth in this area.     

Habitat Partitioning Among Primates in Maracá Island, Roraima, Northern Brazilian Amazonia

I studied a primate community on a tropical rainforest island, in the northernmost area of the Brazilian Amazonia. While walking through six distinct habitats along a 12-km trail, running toward the center of the island—a remote undisturbed area—I collected data on the use of the different forest types and forest strata by the primate community and the formation of either mixed groups or species assemblages. Five species are present: Cebus olivaceus, C. apella, Saimiri sciureus, Ateles belzubuth, and Alouatta seniculus. They seemed to be habitat generalists, using most habitat types. The five species used the higher strata more significantly, probably because Maracá does not present well-defined forest floors, which could be a result of being located in the transition between the great areas of savannah and the Amazonian seasonally dry forests. The five species all formed some polyspecific associations, which involved sharing the available food resource. Mixed groups were significantly more frequent and therefore possibly more important to Saimiri, which was not the case in relation to the other four species. Assemblages, defined as the presence in the same clumped resource, without coordinated activity, of 3 primate species, were recorded primarily in fruiting fig trees. I suggest that assemblages are impelled by food constraints, forcing cofeeding in large seasonal resources, highlighting the ecological importance of figs to these primates. Linear regression models show that the number of feeding bouts in each habitat type is positively related to the number of fruiting trees exploited, but the density of these fruit trees, diversity of plant species, tree height, and total basal area of each habitat type have no relationship to feeding.