Publication Search Results

ID: 158050
Type: article
Authors: Bayona, Germán; Baquero, Mauricio; Ramírez, Catalina; Tabares, Manuela; Salazar, Ana M.; Nova, Giovanny; Duarte, Edward; Pardo, Andrés; Plata, Angelo; Jaramillo, Carlos; Rodríguez, Guillermo; Caballero, Victor; Cardona, Agustín; Montes, Camilo; Gómez Marulanda, Sebastián; Cárdenas‐Rozo, Andrés L.
Abstract: The onset of deformation in the northern Andes is overprinted by subsequent stages of basin deformation, complicating the examination of competing models illustrating potential location of earliest synorogenic basins and uplifts. To establish the width of the earliest northern Andean orogen, we carried out field mapping, palynological dating, sedimentary, stratigraphic and provenance analyses in Campanian to lower Eocene units exposed in the northern Eastern Cordillera of Colombia (Cocuy region) and compare the results with coeval succession in adjacent basins. The onset of deformation is recorded in earliest Maastrichtian time, as terrigenous detritus arrived into the basin marking the end of chemical precipitation and the onset of clastic deposition produced by the uplift of a western source area dominated by shaly Cretaceous rocks. Disconformable contacts within the upper Maastrichtian to middle Palaeocene succession document increasing supply of quartzose sandy detritus from Cretaceous quartzose rocks exposed in eastern source areas. The continued unroofing of both source areas produced a rapid shift in depositional environments from shallow marine in Maastrichtian to fluvial‐lacustrine systems during the Palaeocene‐early Eocene. Supply of immature Jurassic sandstones from nearby western uplifts, together with localized plutonic and volcanic Cretaceous rocks, caused a shift in Palaeocene sandstones composition from quartzarenites to litharenites. Supply of detrital sandy fragments, unstable heavy minerals and Cretaceous to Ordovician detrital zircons, were derived from nearby uplifted blocks and from SW fluvial systems within the synorogenic basin, instead of distal basement rocks. The presence of volcanic rock fragments and 51–59 Ma volcanic zircons constrain magmatism within the basin. The Maastrichtian–Palaeocene sequence studied here documents crustal deformation that correlates with coeval deformation farther south in Ecuador and Peru. Slab flattening of the subducting Caribbean plate produced a wider orogen (>400 km) with a continental magmatic arc and intra‐basinal deformation and magmatism.

ID: 159226
Type: article
Authors: Carrillo-Briceño, Jorge D.; Sánchez, Rodolfo; Scheyer, Torsten M.; Carrillo, Juan D.; Delfino, Massimo; Georgalis, Georgios L.; Kerber, Leonardo; Ruiz-Ramoni, Dami; Birindelli, José L. O.; Cadena, Edwin-Alberto; Rincón, Aldo F.; Chavez-Hoffmeister, Martin; Carlini, Alfredo A.; Carvalho, Mónica R.; Trejos-Tamayo, Ra; Vallejo, Felipe; Jaramillo, Carlos; Jones, Douglas S.; Sánchez-Villagra, Marcelo R.
Abstract: The Pliocene–Pleistocene transition in the Neotropics is poorly understood despite the major climatic changes that occurred at the onset of the Quaternary. The San Gregorio Formation, the younger unit of the Urumaco Sequence, preserves a fauna that documents this critical transition. We report stingrays, freshwater bony fishes, amphibians, crocodiles, lizards, snakes, aquatic and terrestrial turtles, and mammals. A total of 49 taxa are reported from the Vergel Member (late Pliocene) and nine taxa from the Cocuiza Member (Early Pleistocene), with 28 and 18 taxa reported for the first time in the Urumaco sequence and Venezuela, respectively. Our findings include the first fossil record of the freshwater fishes Megaleporinus , Schizodon , Amblydoras , Scorpiodoras , and the pipesnake Anilius scytale , all from Pliocene strata. The late Pliocene and Early Pleistocene ages proposed here for the Vergel and Cocuiza members, respectively, are supported by their stratigraphic position, palynology, nannoplankton, and 86 Sr/ 88 Sr dating. Mammals from the Vergel Member are associated with the first major pulse of the Great American Biotic Interchange. In contrast to the dry conditions prevailing today, the San Gregorio Formation documents mixed open grassland/forest areas surrounding permanent freshwater systems, following the isolation of the northern South American basin from western Amazonia. These findings support the hypothesis that range contraction of many taxa to their current distribution in northern South America occurred rapidly during at least the last 1.5 million years.

ID: 159244
Type: article
Authors: Carvalho, Monica R.; Herrera, Fabiany; Gomez Marulanda, Sebastian; Martinez, Camila; Jaramillo, Carlos
Abstract: Premise of research. Melastomataceae are a diverse and primarily tropical family with a particularly sparse fossil record. Various biogeographic interpretations based on phylogenies, extant distribution, and a limited fossil record have placed the origin of the family in either Laurasia or Gondwana (eastern or western). Methodology. We describe Xystonia simonae M. Carvalho gen. et sp. nov. on the basis of fossil leaves from middle-late Paleocene deposits of the Bogota Formation in central Colombia. These leaves have a characteristic acrodromous venation pattern common among subfamily Melastomatoideae. The leaves are compared with various acrodromously veined fossils and living angiosperms to assess their natural affinities. Pivotal results. The fossil leaves described predate the earliest known occurrence of Melastomatoideae by 5-7 Myr and conflict with previous interpretations that considered Melastomatoideae as Laurasian in origin. In revising the fossil record of Melastomataceae, we reevaluated the age of Melastomaephyllum danielis Huert. to be Miocene (previously Eocene/Oligocene) using pollen obtained from the rock that contained the type specimen. Conclusions. Our findings contribute to the scant early records of Melastomataceae and show that Melastomatoideae was part of a tropical rain forest assemblage by the middle-late Paleocene. Leaf galls and other leaf damage on X. simonae evidence intense and specialized biotic interactions in the early evolution of this lineage.

ID: 159210
Type: article
Authors: Carvalho, Mónica R.; Jaramillo, Carlos; de La Parra, Felipe; Caballero-Rodríguez, Dayenari; Herrera, Fabiany; Wing, Scott; Turner, Benjamin L.; D'Apolito, Carlos; Romero-Báez, Millerlandy; Narváez, Paula; Martínez, Camila; Gutierrez, Mauricio; Labandeira, Conrad C.; Bayona, German; Rueda, Milton; Paez-Reyes, Manuel; Cárdenas, Dairon; Duque, Álvaro; Crowley, James L.; Santos, Carlos; Silvestro, Daniele
Abstract: The end-Cretaceous event was catastrophic for terrestrial communities worldwide, yet its long-lasting effect on tropical forests remains largely unknown. We quantified plant extinction and ecological change in tropical forests resulting from the end-Cretaceous event using fossil pollen (>50,000 occurrences) and leaves (>6000 specimens) from localities in Colombia. Late Cretaceous (Maastrichtian) rainforests were characterized by an open canopy and diverse plant–insect interactions. Plant diversity declined by 45% at the Cretaceous–Paleogene boundary and did not recover for ~6 million years. Paleocene forests resembled modern Neotropical rainforests, with a closed canopy and multistratal structure dominated by angiosperms. The end-Cretaceous event triggered a long interval of low plant diversity in the Neotropics and the evolutionary assembly of today's most diverse terrestrial ecosystem.

ID: 158049
Type: article
Authors: Mander, Luke; Parins‐Fukuchi, Caroline; Dick, Christopher W.; Punyasena, Surangi W.; Jaramillo, Carlos
Abstract: Morphology varies enormously across clades, and the morphology of a trait may reflect ecological function or the retention of ancestral features. We examine the tension between ecological and phylogenetic correlates of morphological diversity through a case study of pollen grains produced by angiosperms in Barro Colorado Island, Panama (BCI). Using a molecular phylogeny of 730 taxa, we demonstrate a statistically significant association between morphological and genetic distance for these plants. However, the relationship is non-linear, and while close relatives share more morphological features than distant relatives, above a genetic distance of ~ 0.7 increasingly distant relatives are not more divergent in phenotype. The pollen grains of biotically pollinated and abiotically pollinated plants overlap in morphological space, but certain pollen morphotypes and individual morphological traits are unique to these pollination ecologies. Our data show that the pollen grains of biotically pol-linated plants are significantly more morphologically diverse than those of abiotically pollinated plants.

ID: 158048
Type: article
Authors: Aguilera, Orangel; Bencomo, Karen; Oliveira de Araújo, Olga M.; Dias, Bruna Borba; Coletti, Giovanni; Lima, Daniel; da Silva-Caminha, Silane A. F.; Polck, Marcia; Martins, Maria Virgínia Alves; Jaramillo, Carlos; Kutter, Vinicius Tavares; Lopes, Ricardo Tadeu
Abstract: Outcrops of Neogene carbonates of the North Brazilian platform occur exclusively along the equatorial coast and represent some of the few existing examples of Neogene carbonate systems of the Atlantic coast of South America. The Pirabas Formation (early-middle Miocene) is the northernmost part of this platform. Although onshore mainly consists of small and scattered outcrops, it considerably extends in the subsurface keeping record of relevant geological and paleontological episodes of tropical South American history. Intending to improve the knowledge of South American carbonate and providing a solid basis for future comparisons between the Pirabas Basin and other, largely subsurface, Cenozoic basins, this research investigates the Aricuru outcrops by combining a standard petrographical and paleontological approach with advanced microCT analyses. The Aricuru area is characterized by mixed siliciclastic-carbonate sand-sized deposits, which probably deposited after the early Miocene according to the palynological assemblage. The bioclastic fraction of the rock is dominated by benthic foraminifera (mostly soritids, amphisteginids, small rotaliids, and small miliolids, typical of marginal marine environments), bryozoans, calcareous algae (Halimeda), echinoderms and mollusks. The abundant siliciclastic fraction together with the taxonomic composition of the foraminiferal, echinodermal, crustacean, ichnofossil and fish assemblages indicates deposition in a tropical coastal environment featuring both protected and more exposed sectors. The carbonate system probably developed under abundant nutrient supply, which fostered heterotroph suspension feeders over hermatypic corals. The demise of this system was most likely caused by a growth in siliciclastic input due to increased rainfall in the coastal area. The sedimentary evolution of the Pirabas Formation is similar to the one of the Foz do Amazonas Basin, and fits well with the general evolutionary trend of Cenozoic carbonate factories of the region, indicating the potential of the Pirabas subsurface record for understanding other Cenozoic basins, their paleoenvironmental significance, and their potential as oil, gas and water reservoirs.

ID: 154319
Type: article
Authors: Aguilera, Orangel; Oliveira de Araújo, Olga M.; Hendy, Austin; Nogueira, Anna A. E.; Nogueira, Afonso C. R.; Wagner Maurity, Clovis; Tavares Kutter, Vinicius; Alves Martins, Maria Virginia; Coletti, Giovanni; Borba Dias, Bruna; Silva-Caminha, Silane; Jaramillo, Carlos; Bencomo, Karen; Lopes, Ricardo Tadeu

ID: 156400
Type: article
Authors: Barreda, Viviana D.; Zamaloa, María del Carmen; Gandolfo, María A.; Jaramillo, Carlos; Wilf, Peter

ID: 157254
Type: article
Authors: Benites-Palomino, Aldo; Aguirre-Fernandez, Gabriel; Moreno-Bernal, Jorge W.; Vanegas, Andres; Jaramillo, Carlos
Abstract: The two extant genera of strictly freshwater dolphinsIniaandPlatanistaare the result of convergent evolution to freshwater environments with reduced visibility. Characterized by their long snout and small melon, these extant taxa are clustered into two clades, Iniidae in South America and Platanistidae in Southern Asia. Their evolutionary history leading to freshwater environments remains mostly unknown, because many of their related fossil species have been found in marine environments. Here, we report riverine dolphin remains (two rostral fragments and a periotic) from two stratigraphic levels of the late middle Miocene (ca. 12.5 Ma) from La Venta, Colombia. The periotic has a reduced cochlear aqueduct mediodorsally oriented, the anterior process is relatively thin, and the dorsal opening of the facial canal is located lateral to the spiral cribriform tract. The rostral fragments are dorsoventrally flattened; the mandible features two longitudinal ventral grooves, and the premaxilla-maxilla suture of the rostrum is located in a deep lateral groove. These characteristics indicate that the specimens belong to Platanistidae, the lineage of the Ganges river dolphinPlatanista. Platanistids had also been recorded on coeval strata from the Fitzcarrald arch, Peru. The occurrence of middle Miocene platanistids in both the La Venta and Fiztcarrald localities suggests that members of this lineage moved into freshwater environments in South America earlier than the ancestors of the modern Amazon river dolphinInia. The subsequent collapse of the Pebas ecosystem could have played a role in the extinction of non-marine Platanistoidea in South America.

ID: 154852
Type: article
Authors: Cadena, Edwin-Alberto; Vanegas, Andrés; Jaramillo, Carlos; Cottle, John M.; Johnson, Thomas A.
Abstract: Mesoclemmys is the most diverse extant genus of South American pleurodires or side-necked turtles, with at least 10 species inhabiting fluvial to littoral environments. Despite this high extant diversity and extensive geographic distribution, the evolutionary history and fossil record of this genus are completely unknown. Here, we describe the first fossil record of this genus, which supports a previous molecular-based hypothesis that indicates a minimum split time of 13.5 Ma between this and other genera of South American chelids. Mesoclemmys vanegasorum, sp. nov., is represented by a nearly complete shell (carapace and plastron) and some postcranial bones found in the middle Miocene (13.6 ± 0.2 Ma), La Victoria Formation, Tatacoa Desert, Colombia, increasing the turtle paleodiversity of La Venta Fauna. It differs from all extant species of Mesoclemmys by vertebral scute 1 reaching the sutural boundary between peripherals 1 and 2; shorter cervical and marginal scutes 1 to 3; pleurals 1 very advanced over the peripherals; pygal bone with a posteromedial shallow notch; vertebral 5 covering half of the pygal bone; small extragulars reaching only half of the epiplastra length; and a fine microvermiculation of the shell. Our phylogenetic results show a close relationship between M. vanegasorum, sp. nov., and the extant M. hogei. The overall morphology and size of Mesoclemmys genus have remained relatively constant for at least the last 13.6 million years. However, its geographic distribution has decreased drastically in northwestern South America, being restricted today to the lower region of the Magdalena River Basin.

ID: 157330
Type: article
Authors: Cardenas, Damian; Jaramillo, Carlos; Oboh-Ikuenobe, Francisca
Abstract: Dinoflagellate cysts and acritarchs are excellent proxies for biostratigraphic and paleoceanographic studies in neritic sequences. However, Neogene marine palynological studies in tropical latitudes are scarce. Here, we analyzed the marine palynological contents (dinoflagellate cysts, acritarchs, foraminiferal test linings and prasinophytes) of 40 samples from a well drilled in northernmost Colombia, southern Caribbean Sea, spanning the late Chattian-late Burgidalian time interval (similar to 24.1-17.3 Ma). We propose a biostratigraphic scheme that includes an upper Chattian-lower Aquitanian Minisphaeridium latirictum Interval Zone (similar to 23.9-22.0 Ma), an upper Aquitanian Achomosphaera alcicornu Interval Zone (-22.0-20.3 Ma), and a Burdigalian Cribroperidinium tenuitabulatum Interval Zone (similar to 20.3-17.5 Ma). Our results reveal several biostratigraphic events that are heterochronous compared to high latitudes. Furthermore, the conspicuous shift from a peridinioid-dominated to a gonyaulacoid-dominated dinoflagellate cyst assemblage towards the Aquitanian-Burdigalian boundary (similar to 20.7 Ma) indicates a reduction in marine primary productivity. This paleoproductivity decline was probably driven by the initial constriction of the Central American Seaway.

ID: 157163
Type: article
Authors: Carrillo, Juan D.; Faurby, Søren; Silvestro, Daniele; Zizka, Alexander; Jaramillo, Carlos; Bacon, Christine D.; Antonelli, Alexandre
Abstract: The biological interchange between North and South America associated with the formation of the Isthmus of Panama is key to defining current gradients of species diversity. A major gap in our understanding of the interchange is its asymmetry, where mammals of North American origin attained higher diversity in South America than vice versa. The prevailing view is that this asymmetry resulted from higher origination of immigrant mammals in South America. In contrast, we find that asymmetry results from high extinction of native mammals in South America, which reduced the diversity of native mammals available to disperse northwards. These results shed light on the legacy of the biotic interchange to understand the current patterns of species diversity across the Americas.The interchange between the previously disconnected faunas of North and South America was a massive experiment in biological invasion. A major gap in our understanding of this invasion is why there was a drastic increase in the proportion of mammals of North American origin found in South America. Four nonmutually exclusive mechanisms may explain this asymmetry: 1) Higher dispersal rate of North American mammals toward the south, 2) higher origination of North American immigrants in South America, 3) higher extinction of mammals with South American origin, and 4) similar dispersal rate but a larger pool of native taxa in North versus South America. We test among these mechanisms by analyzing ∼20,000 fossil occurrences with Bayesian methods to infer dispersal and diversification rates and taxonomic selectivity of immigrants. We find no differences in the dispersal and origination rates of immigrants. In contrast, native South American mammals show higher extinction. We also find that two clades with North American origin (Carnivora and Artiodactyla) had significantly more immigrants in South America than other clades. Altogether, the asymmetry of the interchange was not due to higher origination of immigrants in South America as previously suggested, but resulted from higher extinction of native taxa in southern South America. These results from one of the greatest biological invasions highlight how biogeographic processes and biotic interactions can shape continental diversity.Datasets and code have been deposited in Zenodo (https://doi.org/10.5281/zenodo.3770347) (74).

ID: 158051
Type: article
Authors: da Silva-Caminha, Silane A. F.; D'Apolito, Carlos; Jaramillo, Carlos; Espinosa, Bruno S.; Rueda, Milton
Abstract: The Acre Basin has a complex geology that is related to the Andean uplift and it still is one of the least understood Brazilian sedimentary basins due in part to difficulties in accessing outcrops. Its geological history is related to several subandean basins including Marañon, Ucayali and Madre de Dios in Peru, and the Solimões Basin in Brazil. These basins have potential for oil and gas which raised interest in the Brazilian oil industry since 1930. During this period, 11 wells were drilled in Acre, one of which is herein studied (2CDST001-AC). Available information from this 2600 m-thick borehole suggested an age spanning from the Albian to the Pliocene. We performed palynological analyses in 29 core-samples spread along the well. Our new data indicated much younger ages, spanning from Eocene to late Miocene together with a middle to late Miocene marine incursion. The palynological assemblage of the Solimões Formation in the Acre basin is similar to that of the adjacent Solimões Basin, but with a much thicker stratigraphic sequence offering a greater potential to unravel the history of western Amazonia during the Cenozoic.

ID: 158052
Type: article
Authors: Jaramillo, Carlos; Sepulchre, Pierre; Cardenas, Damian; Correa‐Metrio, Alexander; Moreno, J. E.; Trejos, Raul; Vallejos, Diego; Hoyos, Natalia; Martínez, Camila; Carvalho, Daniella; Escobar, Jaime; Oboh‐Ikuenobe, Francisca; Prámparo, Mercedes B.; Pinzón, Diego
Abstract: Dry biomes occupy ~35% of the landscape in the Neotropics, but these are heavily human‐disturbed. In spite of their importance, we still do not fully understand their origins and how they are sustained. The Guajira Peninsula in northern Colombia is dominated by dry biomes and has a rich Neogene fossil record. Here, we have analyzed its changes in vegetation and precipitation during the Neogene using a fossil pollen and spore dataset of 20 samples taken from a well and we also dated the stratigraphic sequence using microfossils. In addition, we analyzed the pollen and spore contents of 10 Holocene samples to establish a modern baseline for comparison with the Neogene as well as a study of the modern vegetation to assess both its spatial distribution and anthropic disturbances during the initial stages of European colonization. The section was dated to span from the latest Oligocene to the early Miocene (~24.2 to 17.3 Ma), with the Oligocene/Miocene boundary being in the lower Uitpa Formation. The early Miocene vegetation is dominated by a rainforest biome with a mean annual precipitation of ~2,000 mm/yr, which strongly contrasts with Guajira's modern xerophytic vegetation and a precipitation of ~300 mm/yr. The shift to the dry modern vegetation probably occurred over the past three millions years, but the mechanism that led to this change is still uncertain. Global circulation models that include the vegetation could explain the ancient climate of Guajira, but further work is required to assess the feedbacks of vegetation, precipitation, and CO2.