Publication Search Results

ID: 158396
Type: article
Authors: Alonso-Garcia, Marta; Grewe, Felix; Payette, Serge; Villarreal, Juan Carlos A.
Keywords: STRI
Abstract: PREMISE Lichens are one of the main structural components of plant communities in the North American boreal biome. They play a pivotal role in lichen woodlands, a large ecosystem situated north of the closed-crown forest zone, and south of the forest-tundra zone. In Eastern Canada (Quebec), there is a remnant LW found 500 km south of its usual distribution range, in the Parc National des Grands-Jardins, originated mainly because of wildfires. We inferred the origin of the lichen Cladonia stellaris from this LW and assessed its genetic diversity in a postfire succession. METHODS We genotyped 122 individuals collected across a latitudinal gradient in Quebec. Using the software Stacks, we compared four different approaches of locus selection and single-nucleotide polymorphism calling. We identified the best fitting approach to investigate population structure and estimate genetic diversity of C. stellaris. RESULTS Populations in southern Quebec are not genetically different from those of northern LWs. The species consists of at least four phylogenetic lineages with elevated levels of genetic diversity and low co-ancestry. In Parc National des Grands-Jardins, we reported high values of genetic diversity not related with time since fire disturbance and low genetic differentiation among populations with different fire histories. CONCLUSIONS This first population genomic study of C. stellaris is an important step forward to understand the origin and biogeographic patterns of lichen woodlands in North America. Our findings also contribute to the understanding of the effect of postfire succession on the genetic structure of the species.

ID: 158420
Type: article
Authors: Amador-Vargas, Sabrina; Orribarra, Vivian Sara; Portugal-Loayza, Ana; Fernandez-Marin, Hermogenes
Keywords: STRI
Abstract: Ants in obligate defense mutualisms with plants protect them against potentially damaging organisms. In the swollen-thorn acacias, organisms linked to the plant inform about the interaction between the tree and the resident ant colony. Some organisms coexist with the aggressive mutualistic ants: specialized herbivores and organisms using the enemy-free space. Conversely, trees inhabited by non-defending ants usually hold a greater load of generalist herbivores and are avoided by organisms looking for the ant protection. We aimed to elucidate the association type between swollen-thorn acacias (Vachellia collinsii) and the almost unstudied Pseudomyrmex simulans ants from Panama. We compared the presence of non-ant organisms on trees inhabited by P. simulans, a well-known mutualist (P. spinicola) and a facultative parasite (non-defending ants; Crematogaster crinosa). We recorded non-ant organisms (e.g., stem galls, acacia true bugs, spiders) that nest, lay eggs, or live on the trees. Except for stem galls, all other non-ant organisms were mostly or exclusively found on trees with the mutualists, which is also the most common resident ant. P. simulans is less able to deter galling midges (Cecidomyiidae) than C. crinosa and even less than P. spinicola, because trees with P. simulans were more likely to have galls and in greater densities than on C. crinosa-trees, and even more than on P. spinicola-inhabited trees. The mechanism by which the Cecidomyiids occur in greater proportion on trees with P. simulans and C. crinosa is still unknown, but the pattern indicates an herbivory specialization or a potentially obligate weaker defender of the swollen-thorn acacias. Abstract in Spanish is available with online material

ID: 158502
Type: article
Authors: Benites‐Palomino, Aldo; Vélez‐Juarbe, Jorge; Collareta, Alberto; Ochoa, Diana; Altamirano, Ali; Carré, Matthieu; Laime, Manuel J.; Urbina, Mario; Salas‐Gismondi, Rodolfo
Keywords: STRI

ID: 158170
Type: article
Authors: Boyle, Michael J. W.; Bishop, Tom R.; Luke, Sarah H.; van Breugel, Michiel; Evans, Theodore A.; Pfeifer, Marion; Fayle, Tom M.; Hardwick, Stephen R.; Lane-Shaw, Rachel Isolde; Yusah, Kalsum M.; Ashford, Imogen C. R.; Ashford, Oliver S.; Garnett, Emma; Turner, Edgar C.; Wilkinson, Clare L.; Chung, Arthur Y. C.; Ewers, Robert M.
Keywords: STRI
Abstract: Logging and habitat conversion create hotter microclimates in tropical forest landscapes, representing a powerful form of localised anthropogenic climate change. It is widely believed that these emergent conditions are responsible for driving changes in communities of organisms found in modified tropical forests, although the empirical evidence base for this is lacking. Here we investigated how interactions between the physiological traits of genera and the environmental temperatures they experience lead to functional and compositional changes in communities of ants, a key organism in tropical forest ecosystems. We found that the abundance and activity of ant genera along a gradient of forest disturbance in Sabah, Malaysian Borneo, was defined by an interaction between their thermal tolerance (CTmax) and environmental temperature. In more disturbed, warmer habitats, genera with high CTmax had increased relative abundance and functional activity, and those with low CTmax had decreased relative abundance and functional activity. This interaction determined abundance changes between primary and logged forest that differed in daily maximum temperature by a modest 1.1 degrees C, and strengthened as the change in microclimate increased with disturbance. Between habitats that differed by 5.6 degrees C (primary forest to oil palm) and 4.5 degrees C (logged forest to oil palm), a 1 degrees C difference in CTmax among genera led to a 23% and 16% change in relative abundance, and a 22% and 17% difference in functional activity. CTmax was negatively correlated with body size and trophic position, with ants becoming significantly smaller and less predatory as microclimate temperatures increased. Our results provide evidence to support the widely held, but never directly tested, assumption that physiological tolerances underpin the influence of disturbance-induced microclimate change on the abundance and function of invertebrates in tropical landscapes. A free Plain Language Summary can be found within the Supporting Information of this article.

ID: 158466
Type: article
Authors: Ceron-Souza, Ivania; Barreto, Maria Beatriz; Barreto-Pittol, Eduardo; Silva, Angie; Feliner, Gonzalo N.; Medina, Ernesto
Keywords: STRI
Abstract: Rhizophora is the dominant genus of mangrove forests on the Atlantic coast of northern South America. What determines the zonation frequently observed in sympatric populations of the two neotropical species, R. mangle and R. racemosa, and their hybrids, R. x harrisonii, is an open question. The most widely held hypothesis is that differences in salinity tolerance among the taxonomic groups explain the observed zonation. To address this question, we analyzed the elemental composition of soils and canopy leaves from 60 Rhizophora spp. trees distributed in different intertidal zones of an estuarine site of the Paria Gulf, Venezuela. The low intertidal zone showed lower salinity, organic matter, C, N, S, and Na, and higher bulk density, Al, Fe, and Mn concentrations compared with the higher intertidal zones. Using morphological characters and microsatellite molecular markers, we identified 39 pure R. mangle, 19 hybrids, and only two pure R. racemosa. We found that both intertidal position and taxonomic groups explained most of the differences in leaf variables measured across trees. The ratio Mg/Ca, however, was higher in R. mangle than in R. racemosa and hybrids regardless of intertidal position. Moreover, at some specific intertidal position, R. mangle differed from R. racemosa and hybrids in the values of C, N, K, Mg, Fe, Mn, C/N, K/Ca, S/Ca, and delta C-13. We conclude that despite the scarcity of R. racemosa and the absence of a clear species zonation, our results suggest that R. mangle copes with salinity differently than R. racemosa and R. x harrisonii.

ID: 158472
Type: article
Authors: Collin, Rachel; Venera-Ponton, Dagoberto E.; Macdonald, Kenneth; Driskell, Amy C.; Boyle, Michael J.
Keywords: NMNH; NH-SMS; STRI; NH-LAB
Abstract: The morphological diversity of marine annelid larvae is stunning. Although many of the larval forms have been categorized as trochophores or modified trochophores, there are a few groups with distinctive larval features that make them easy to distinguish from other annelid larvae. We collected 252 annelid larvae from the plankton, with particular emphasis on oweniids, polygordiids, and thalassematids (i.e., echiurans) and sequenced fragments of their cytochrome c oxidase subunit 1 and 16S ribosomal RNA genes. We found six oweniid, five polygordiid, and eight thalassematid OTUs. Thalassematids were found only in samples from the Pacific, and oweniids were found only in Caribbean samples. Among the oweniids we found two distinct morphotypes, one with a narrow, cloche shape and another that had a wider and more rectangular shape with clearly developed lappets. Among the polygordiids, we identified one larva as Polygordius eschaturus and several larvae as Polygordius jenniferae. All larvae, except for the P. eschaturus, which was at a stage too early to make a determination, were endolarvae. Among the thalassematids, we identified larvae of Ochetostoma edax and found seven unidentified OTUs. Finally, 150 miscellaneous polychaete larvae were sequenced, representing similar to 76 OTUs. Four rostraria larvae from the Caribbean, whose sequences confirm the long-held assumption that they are amphinomids, could not be identified to species. In total only 5% of these OTUs could be identified to species with known sequences, and most could not be identified to genus or even family with reasonable certainty. It is clear that this poor coverage in the reference databases will limit metabarcoding efforts to document numbers of OTUs, and that DNA barcodes will be of limited use for identifying neotropical marine annelids until reference databases have improved their coverage of this group.

ID: 158488
Type: article
Authors: De Faria, Bruno L.; Marano, Gina; Piponiot, Camille; Silva, Carlos A.; Dantas, Vinicius de L.; Rattis, Ludmila; Rech, Andre R.; Collalti, Alessio
Keywords: STRI
Abstract: In recent decades, droughts, deforestation and wildfires have become recurring phenomena that have heavily affected both human activities and natural ecosystems in Amazonia. The time needed for an ecosystem to recover from carbon losses is a crucial metric to evaluate disturbance impacts on forests. However, little is known about the impacts of these disturbances, alone and synergistically, on forest recovery time and the resulting spatiotemporal patterns at the regional scale. In this study, we combined the 3-PG forest growth model, remote sensing and field derived equations, to map the Amazonia-wide (3 km of spatial resolution) impact and recovery time of aboveground biomass (AGB) after drought, fire and a combination of logging and fire. Our results indicate that AGB decreases by 4%, 19% and 46% in forests affected by drought, fire and logging + fire, respectively, with an average AGB recovery time of 27 years for drought, 44 years for burned and 63 years for logged + burned areas and with maximum values reaching 184 years in areas of high fire intensity. Our findings provide two major insights in the spatial and temporal patterns of drought and wildfire in the Amazon: (1) the recovery time of the forests takes longer in the southeastern part of the basin, and, (2) as droughts and wildfires become more frequent-since the intervals between the disturbances are getting shorter than the rate of forest regeneration-the long lasting damage they cause potentially results in a permanent and increasing carbon losses from these fragile ecosystems.

ID: 157994
Type: article
Authors: Eren, A. Murat; Kiefl, Evan; Shaiber, Alon; Veseli, Iva; Miller, Samuel E.; Schechter, Matthew S.; Fink, Isaac; Pan, Jessica N.; Yousef, Mahmoud; Fogarty, Emily C.; Trigodet, Florian; Watson, Andrea R.; Esen, Ozcan C.; Moore, Ryan M.; Clayssen, Quentin; Lee, Michael D.; Kivenson, Veronika; Graham, Elaina D.; Merrill, Bryan D.; Karkman, Antti; Blankenberg, Daniel; Eppley, John M.; Sjodin, Andreas; Scott, Jarrod J.; Vazquez-Campos, Xabier; McKay, Luke J.; McDaniel, Elizabeth A.; Stevens, Sarah L. R.; Anderson, Rika E.; Fuessel, Jessika; Fernandez-Guerra, Antonio; Maignien, Lois; Delmont, Tom O.; Willis, Amy D.
Keywords: STRI
Abstract: Big data abound in microbiology, but the workflows designed to enable researchers to interpret data can constrain the biological questions that can be asked. Five years after anvi'o was first published, this community-led multi-omics platform is maturing into an open software ecosystem that reduces constraints in 'omics data analyses.

ID: 157161
Type: article
Authors: Gudnitz, Maria N.; Collins, Laurel S.; O'Dea, Aaron
Keywords: STRI
Abstract: The distribution and community structure of mid-Holocene, tropical benthic foraminiferal assemblages were analyzed for their correspondence to marine habitats and invertebrate facies. Benthic foraminifera are useful for paleoenvironmental reconstructions because the modern ecology of many species found as Quaternary fossils is known. Samples were collected from ~30,000 m2 of an excavated Acropora cervicornis-dominated mid-Holocene reef with an age of ~6 kyr on Isla Colón, Bocas del Toro, Caribbean Panama. Bulk sediment samples were collected from a maximum depth of ~7 m below modern mean sea level and classified into five biofacies based on field observations of primarily corals and mollusks: 1) A. cervicornis-dominated reef, 2) molluscan mud, 3) Porites/Agaricia, 4) fringing reef and 5) seagrass. Sediment carbon and grain size analyses along with the relative abundance of species per sample and Fisher's alpha diversity index were used to compare sample similarity and environmental variables to identify any relationships. Most samples contained high total inorganic carbon content and poorly sorted, medium-coarse sediments. Principle component analysis of sediment grain size and carbon values did not show a clear association between samples, habitat type or location of trenches in respect to one another. Acropora cervicornis and other reefal samples contained the greatest foraminiferal diversity and were indicative of normal-marine conditions, while molluscan mud samples with high total organic carbon content were least diverse resulting from dominant Ammonia and Elphidium taxa. Seagrass samples were differentiated from molluscan mud samples and had similar diversities and species assemblages to Porites/Agaricia samples. Based on the distribution of foraminiferal species across this mid-Holocene coral reef, we conclude that it was a patch reef similar to those of modern Bocas del Toro. Results from this study can be used for comparison to modern foraminiferal studies to investigate whether the modern habitats of BDT are significantly different from the pristine reefs of the mid-Holocene.

ID: 158464
Type: article
Authors: Heineman, Katherine D.; Turner, Benjamin L.; Dalling, James W.
Keywords: STRI
Abstract: Resprouting capacity is a key component of plant life history. While resprouting requires substantial nutrient reserves to support new growth, the influence of soil fertility on resprouting is largely unknown. We tested whether the frequency of multi-stemmed trees, a potential indicator of resprouting history, is associated with low soil fertility, reflecting selection for conservative life histories that enhance survival, or with high fertility, reflecting greater resource availability to support regrowth. Data from the Barro Colorado Island (BCI) 50-ha plot in Panama showed that multi-stemmed trees are more likely to resprout during their lifetime than single-stemmed trees, and that multiple stem frequency has a strong taxonomic signal for adult trees. To test how multiple stem frequency varies with demographic rates and nutrient allocation strategies, we compiled functional trait datasets for 71 species from lowland forest on BCI and 43 species from lower montane forest in western Panama. We also assessed environmental correlates of community-wide multiple stem frequency in thirty-seven 1-ha lowland plots in the Panama Canal watershed and twelve 1-ha montane plots in western Panama, spanning gradients of rainfall and soil fertility. Multiple stem frequency was not correlated with species demographic rates or wood density, suggesting that resprouting is unrelated to classical 'persistence' traits in neotropical tree species. Multiple stem frequency of tree species occurring on BCI was weakly but significantly positively correlated with regional soil phosphorus associations, but unrelated to foliar nutrient concentrations. Multiple stem frequency covaried strongly with soil and tissue nutrient status across fertility gradients. It was significantly positively correlated with nutrient allocation traits, including foliar phosphorus and wood nitrogen and phosphorus, among species sampled across soil habitats in western Panama. At the community level, the proportion of woody stems >10 cm DBH with at least one multiple stem increased with plant available soil phosphorus. Synthesis. These results suggest a novel mechanism by which soil phosphorus availability influences tree recruitment and forest dynamics by facilitating resprouting. Future experiments should seek to understand whether soil fertility mediates resprouting frequency through nutrient supply directly, or via the formation of enhanced wood nutrient reserves.

ID: 158047
Type: article
Authors: Kime, Nicole M.; Goutte, Sandra; Ryan, Michael J.
Keywords: STRI

ID: 158471
Type: article
Authors: Knight, Nicole S.; Guichard, Frederic; Altieri, Andrew H.
Keywords: STRI
Abstract: Aim The temperature constraint hypothesis proposes that marine herbivorous fishes are rare at high latitudes relative to carnivorous fishes because low temperatures impair the digestion of plant material. To test this hypothesis, we compared the effects of temperature on the digestive performance and investment in digestion of marine fishes across trophic groups. Location Global marine ecosystems. Major taxa studied Marine fishes. Methods We analysed data from 304 species consuming a range of diets to quantify the effects of temperature on three indicators of digestive performance and investment: gut passage time, absorption efficiency, and gut length. Results Decreasing temperatures increase gut passage time in fishes consuming macroalgae more than fishes consuming other fish or invertebrates. Low temperatures do not impair absorption efficiency in fishes regardless of diet, but herbivores have lower absorption efficiencies than carnivores overall. Gut length decreases with decreasing temperature in all trophic groups. Main conclusions Our analyses reveal limited evidence to support the temperature constraint hypothesis. Low temperatures slow digestion more in fishes consuming macroalgae than those consuming animal prey; however, this may not reflect a meaningful disadvantage for herbivores but rather could be explained by greater representation of fishes relying on microbial fermentation at high latitudes. Herbivorous fishes absorb nutrients and energy from their food in similar proportions regardless of temperature, in contrast to the expectations of the temperature constraint hypothesis. Decreased gut length was associated with decreasing temperature across all trophic groups, likely due to improved food quality at high latitudes, which should benefit all trophic groups by reducing their required investment in gut tissues. Altogether, our findings run counter to the general hypothesis that low temperatures disadvantage the digestion of plant material and suppress the diversity and abundance of herbivorous fishes at high latitudes.

ID: 158314
Type: article
Authors: Lattenkamp, Ella Z.; Nagy, Martina; Drexl, Markus; Vernes, Sonja C.; Wiegrebe, Lutz; Knornschild, Mirjam
Keywords: STRI
Abstract: Differences in auditory perception between species are influenced by phylogenetic origin and the perceptual challenges imposed by the natural environment, such as detecting prey- or predator-generated sounds and communication signals. Bats are well suited for comparative studies on auditory perception since they predominantly rely on echolocation to perceive the world, while their social calls and most environmental sounds have low frequencies. We tested if hearing sensitivity and stimulus level coding in bats differ between high and low-frequency ranges by measuring auditory brainstem responses (ABRs) of 86 bats belonging to 11 species. In most species, auditory sensitivity was equally good at both high- and low-frequency ranges, while amplitude was more finely coded for higher frequency ranges. Additionally, we conducted a phylogenetic comparative analysis by combining our ABR data with published data on 27 species. Species-specific peaks in hearing sensitivity correlated with peak frequencies of echolocation calls and pup isolation calls, suggesting that changes in hearing sensitivity evolved in response to frequency changes of echolocation and social calls. Overall, our study provides the most comprehensive comparative assessment of bat hearing capacities to date and highlights the evolutionary pressures acting on their sensory perception.

ID: 158168
Type: article
Authors: Legett, Henry D.; Aihara, Ikkyu; Bernal, Ximena E.
Keywords: STRI
Abstract: Haematophagous insects can rely on specialized host-seeking behaviors to locate hosts. Some frog-biting flies, for example, eavesdrop on the conspicuous acoustic signals produced by male frogs and toads. Using such auditory cues to locate a host imposes an additional challenge: how to recognize appropriate sounds when different frog species produce calls with varying acoustic properties. The limited knowledge of antennal hearing in dipteran insects hinders our ability to understand how eavesdropping flies detect and recognize frog calls. Behavioral studies suggest that frog-biting flies use broad acoustic templates to detect and recognize their victims. Here, we use within-species call variation to examine the acoustic preferences in frog-biting flies. Specifically, we examine the attraction of frog-biting mosquitoes (Uranotaenia spp.) and midges (Corethrella nippon) to the calls of a Japanese treefrog, the Ryukyu Kajika frog (Buergeria japonica), on Iriomote Island, Japan. Male Ryukyu Kajika frogs produce two call types. While both calls have a high frequency peak (3 kHz), the first call type (Type I) also contains a lower frequency peak (1.8 kHz) absent in the second call type (Type II). Using field phonotaxis experiments we found that Type I calls are more attractive to both frog-biting mosquitoes and midges. Thus, our results suggest that the frog-biting Nematoceran flies in this community are biased towards the acoustic properties of Type I calls. We discuss this finding in the context of the evolution of antennal hearing in flies.

ID: 158275
Type: article
Authors: López-Blanco, Charo; Rodríguez-Abaunza, Gloria Alejandra; Seitz, Carina; Perez, Laura; Cuña-Rodriguez, Carolina; Fontana, Sonia L.
Keywords: STRI
Abstract: The Pampean region is a crucial area to obtain sensitive paleoclimatic lacustrine archives due to the presence of shallow environments in a territory non impacted by humans until the last centuries. In this study, we provide a paleoecological reconstruction for the last ca. 700 years based on a multiproxy lacustrine record from Laguna Blanca Grande, in Olavarría (Buenos Aires, Argentina). Our inferences, which were based on sedimentary properties, diatom, cladoceran and ostracod assemblages, offered interesting information about hydroclimatic variability and nutrient increase. Changes in relative abundances on diatoms, specifically on Aulacoseira granulata and Aulacoseira granulata var. angustissima and fragilariods, were used to infer shifts in nutrient conditions. The remainder proxies together indicated small lake level changes. Reconstructed hydroclimatic conditions in Laguna Blanca Grande are consistent with previous paleoecological inferences indicating a humid phase around ca. AD 1450 and progressive drier conditions ca. AD 1530–1900. A flood gate construction and an increase of nutrients in the lake revealed a higher human pressure due to population increase and land-use changes during the last century. Further studies on taxonomy and autecology of microcrustaceans are needed to effectively unlock the information contained in biological proxies from Sudamerican records.

ID: 158163
Type: article
Authors: Ly, Sophia; Collin, Rachel
Keywords: STRI

ID: 157991
Type: article
Authors: Magee, Lukas; Wolf, Amy; Howe, Robert; Schubbe, Jonathan; Hagenow, Kari; Turner, Benjamin
Keywords: STRI
Abstract: Survival and growth of forest tree seedlings are influenced by many abiotic and biotic forces that may vary across space and time. The simultaneous influences of habitat heterogeneity, temporal environmental variability (including disturbance regimes), and biotic interactions are difficult to disentangle, yet understanding the relative importance of these factors for tree seedling dynamics is critical for conservation of forest biodiversity. Most long term, spatially explicit studies of tree seedling ecology have been set in the tropics; much less attention has been given to tree seedlings in temperate forests. We monitored the survival of over 3000 individual seedlings over an eight-year period in a temperate forest in northeast Wisconsin, USA. Results from four seedling censuses demonstrated that both conspecific density and environmental variables significantly affected seedling survival. Higher densities of conspecific trees consistently reduced the probability of seedling survival over time. At the community level, relatively common species were negatively influenced by neighboring conspecific trees and exhibited higher per capita and per basal area mortality. The negative impacts of high conspecific tree density were most pronounced in areas of higher light and moisture, but these interactions varied over time, as did the importance of other abiotic variables. Patterns of less common species were more clearly explained by abiotic variables, with shifting relevance of specific variables according to species abundance. Conspecific negative density dependence, which interacts with resource gradients, and habitat conditions that shift over time are influencing community composition in this northern temperate forest.

ID: 158335
Type: article
Authors: Miller, Matthew J.; Bermingham, Eldredge; Turner, Benjamin L.; Touchon, Justin C.; Johnson, Andrew B.; Winker, Kevin
Keywords: STRI
Abstract: Despite evidence that species' traits affect rates of bird diversification, biogeographic studies tend to prioritise earth history in Neotropical bird speciation. Here we compare mitochondrial genetic differentiation among 56 co-distributed Neotropical bird species with varying ecologies. The trait 'diet' best predicted divergence, with plant-dependent species (mostly frugivores and nectivores) showing lower levels of genetic divergence than insectivores or mixed-diet species. We propose that the greater vagility and demographic instability of birds whose diets rely on fruit, seeds, or nectar - known to vary in abundance seasonally and between years - relative to birds that eat primarily insects, drives episodic re-unification of otherwise isolated populations, resetting the divergence 'clock'. Testing this prediction using coalescent simulations, we find that plant-dependent species show stronger signals of recent demographic expansion compared to insectivores or mixed-diet species, consistent with this hypothesis. Our study provides evidence that localised ecological phenomena scale up to generate larger macroevolutionary patterns.

ID: 158079
Type: article
Authors: Montes, C.; Silva, C. A.; Bayona, G. A.; Villamil, R.; Stiles, E.; Rodriguez-Corcho, A.; Beltran-Triviño, A.; Lamus, F.; Muñoz-Granados, M. D.; Pérez-Angel, L. C.; Hoyos, N.; Gomez, S.; Galeano, J. J.; Romero, E.; Baquero, M.; Cardenas-Rozo, A.; von Quadt, A.
Keywords: STRI
Abstract: Integration of several geologic lines of evidence reveals the prevalence of a lowland trans-Andean portal communicating western Amazonia and the westernmost Andes from at least middle Miocene until Pliocene times. Volcanism and crustal shortening built up relief in the southernmost Central and Eastern Cordilleras of Colombia, closing this lowland gap. Independent lines of evidence consist first, of field mapping in the Tatacoa Desert with a coverage area of ∼381 km², 1,165 km of geological contact traces, 164 structural data points, and 3D aerial digital mapping models. This map documents the beginning of southward propagation of the southernmost tip of the Eastern Cordillera's west-verging, fold-and-thrust belt between ∼12.2 and 13.7 Ma. Second, a compilation of new and published detrital zircon geochronology in middle Miocene strata of the Tatacoa Desert shows three distinctive age populations: middle Miocene, middle Eocene, and Jurassic; the first two sourced west of the Central Cordillera, the latter in the Magdalena Valley. Similar populations with the three distinctive peaks have now been recovered in western Amazonian middle Miocene strata. These observations, along with published molecular and fossil fish data, suggest that by Serravallian times (∼13 Ma), the Northern Andes were separated from the Central Andes at ∼3°N by a fluvial system that flowed into the Amazon Basin through the Tatacoa Desert. This paleogeographic configuration would be similar to a Western Andean, or Marañon Portal. Late Miocene flattening of the subducting Nazca slab caused the eastward migration of the Miocene volcanic arc, so that starting at ∼4 Ma, large composite volcanoes were built up along the axis of today's Central Cordillera, closing this lowland Andean portal and altering the drainage patterns to resemble a modern configuration.

ID: 158392
Type: article
Authors: Munoz-Romo, Mariana; Page, Rachel A.; Kunz, Thomas H.
Keywords: STRI
Abstract: Sexual dimorphism is the condition in which males and females of the same species are easily distinguished by specific traits (secondary sex characteristics), often related to body size, colour patterns, weapons, and ornaments. Males of many mammal species tend to be larger or more ornamented than females, and these characteristics tend to be more pronounced in polygynous, diurnal, and open-habitat species. Bats have long been considered a largely non-sexually dimorphic group due to lack of conspicuous differences in body size and other cranial and skeletal characters. However, bats, like many mammals, exhibit a diverse array of soft-tissue integumentary glands and non-glandular odour-producing structures with intense odorous substances that have not been thoroughly investigated, although postulated functions include facilitating mate selection in their generally polygynous associations. To date, there has been no systematic assessment of the occurrence or expression of sexually dimorphic traits in bats, many of which show intriguing sexual dimorphism in soft tissue, and most of which involve intense odours. In this study, we review evidence of integumentary glands and non-glandular odour-producing structures known in bats, as a first step towards identifying future research pathways to study sexual dimorphism in bats. Highly variable glands and non-glandular odour-producing structures have been noticed in ten different regions of the body, but are most frequently found on the head and the ventral region of the neck. They have been described in nearly 9% of bat species and in 70% of 21 extant bat families. Our review, based on extremely scattered and unevenly detailed literature, unveils the extraordinary sexual dimorphism that has been observed in Chiroptera to date, identifying not only target body parts where sexually dimorphic traits are likely to be found, but also critical avenues for future investigation and discoveries, and stressing the importance of the timing of secondary sexual trait observations, behavioural studies, and chemical analyses.