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Papers by santiago duque

Morphological and DNA sequence data has been used to propose hypotheses of relationships within t... more Morphological and DNA sequence data has been used to propose hypotheses of relationships within the Characiformes with minimal comparative discussion of causes underpinning the major intraordinal diversification patterns. We explore potential primary morphological factors controlling the early diversification process in some Neotropical characiforms as the first step to identifying factors contributing to the pronounced intraordinal morphological and species diversity. A phylogenetic reconstruction based on 16S rDNA (mitochondrial) and 18S rDNA (nuclear) genes provided the framework for the identification of the main morphological differences among the Acestrorhynchidae, Anostomidae, Characidae, Ctenoluciidae, Curimatidae, Cynodontidae, Gasteropelecidae, Prochilodontidae and Serrasalmidae. Results indicate an initial split into two major groupings: (i) species with long dorsal-fin bases relative to the size of other fins (Curimatidae, Prochilodontidae, Anostomidae, Serrasalmidae) which primarily inhabit lakes, swamps, and rivers (lineage I); and (ii) species with short dorsal-fin bases (Acestrorhynchidae, Gasteropelecidae, Characidae) which primarily inhabit creeks and streams (lineage II). The second diversification stage in lineage I involved substantial morphological diversification associated with trophic niche differences among the monophyletic families which range from detritivores to large item predators. Nonmonophyly of the Characidae complicated within lineage II analyzes but yielded groupings based on differences in pectoral and anal fin sizes correlated with life style differences.

Biota Colombiana Instituto de Investigación de Recursos Biológicos Alexander von Humboldt biotaco... more Biota Colombiana Instituto de Investigación de Recursos Biológicos Alexander von Humboldt biotacol@humboldt.org.co ISSN (Versión impresa): 0124-5376 COLOMBIA ... 2005 José Iván Mojica / Germán Galvis / Fernando Arbeláez / Marisol Santos / Silvia Vejarano / Edgar ...

... 1838 Trachelomonas volvocinopsis var. tigr A TB 034 O, M volvocinopsis Swir., 1914 Trachelomo... more ... 1838 Trachelomonas volvocinopsis var. tigr A TB 034 O, M volvocinopsis Swir., 1914 Trachelomonas zingeri Roll, 1925 poho TB 110 M ... baileyi fo. baileyi yahu A TB 057, 300 O, MNord., 1880 Gonatozygon aculeatum var. aculeatum isro yahu AM A TB 056, 516 O, M ...

Algological Studies, 2012

A fl oristic and ultrastructural study on naked green Euglenophyta was performed in the Amazonian... more A fl oristic and ultrastructural study on naked green Euglenophyta was performed in the Amazonian and Caribbean regions of Colombia, where a large number of taxa are contained in several freshwater bodies. A total of 37 taxa were recorded, 1 belonging to the genus Cryptoglena Ehr., 9 to Lepocinclis Perty, 1 to Monomorphina Meresch., and 26 to Phacus Duj. From the identifi ed taxa, 22 were recorded for the fi rst time in Colombia, 2 in the Amazonian region, and 14 in the Caribbean region. Among the taxa described in this work we propose Phacus sesquitortus var. longicauda as a new variety. In addition, 9 taxa were examined by scanning electron microscopy (SEM) to illustrate in detail their ultrastructure; 3 of them were examined for the fi rst time under this method.

Revista de Biología Tropical, 2009

Caldasia, 2015

Para caracterizar las fuentes primarias de carbono del zooplancton y su flujo en la red trófica e... more Para caracterizar las fuentes primarias de carbono del zooplancton y su flujo en la red trófica en un lago de inundación próximo a la ciudad de Leticia (Amazonas, Colombia), se hicieron recolectas de bacterias, detritos, fitoplancton, perifiton y zooplancton entre mayo de 2010 y mayo de 2011. El zooplancton se usó como integrador por su posición central en la red trófica y para tal fin fueron analizados en términos de δ 13 C y δ 15 N los organismos concentrados en malla de 60μm, representados por cladócera, copépoda ciclopoida y rotífera. Las muestras fueron concentradas con filtros GF/F pre quemados para su análisis en el laboratorio de isótopos estables de la UNESP en Botucatú (SP). Los valores de δ 13 C muestran una relación trófica pobre entre el zooplancton (-37,99‰ ± 2,14) y sus fuentes potenciales como fitoplancton (-32,53‰ ± 1,97) perifiton (-32,56‰ ± 1,55) y detritos (-32,27‰ ± 0,81). Por otra parte, si bien los valores de δ 15 N del zooplancton (6,12‰ ± 0,59) complementan la apreciación sobre el fitoplancton (7,38‰ ± 1,1), sugieren el consumo de perifiton empobrecido (1,15‰ ± 0,07) y de detrito (5,23‰ ± 4,76). Los valores bajos de δ 13 C son asociados con el consumo de una fracción de carbono metanogénico, como ha sido demostrado en el hipolimnio de lagos de inundación; de la misma forma que su aporte a las capas superiores de la columna de agua durante eventos de mezcla. Esta especialización del zooplancton en consumir una fracción de varios gremios tróficos puede ser el resultado de la variabilidad intrínseca de los recursos, como resultado de las variaciones biogeoquímicas asociadas con la hidrología del lago.

Limnology and Oceanography: Methods, 2008

The problem using the CHEMTAX program in freshwater environments is that the few matrices of pigm... more The problem using the CHEMTAX program in freshwater environments is that the few matrices of pigment ratios available have not been tested in a wide range of environments. Sixteen Amazonian, Andean, and Caribbean lakes, lagoons, and swamps were sampled over a year. The aim was to determine if it was possible to obtain a reliable matrix of input pigment ratios that may be used in freshwater habitats with different environmental conditions. There were no clear differences among regions for most of the ratios of marker pigments to Chlorophyll a (Chl a) in most of the phytoplankton groups. Only the zeaxanthin/Chl a ratio showed clear variations among areas. The estimates for the mean relative contribution of each phytoplankton group calculated for the pigment ratios obtained in each separate habitat and season were very similar to the estimates calculated using the average pigment ratio obtained for all habitats and seasons. Our study suggests that the matrix of the average pigment ratio obtained in this study can be used to estimate phytoplankton class abundances with the CHEMTAX program in freshwater habitats with different limnological conditions.

Aquatic Botany, 2007

The abundance and taxonomic composition of periphyton attached to the bladders and phytoplankton ... more The abundance and taxonomic composition of periphyton attached to the bladders and phytoplankton associated with the aquatic carnivorous plant Utricularia foliosa were quantified, to determine whether periphyton associated with U. foliosa would enhances predation success. Bladder size, periphyton abundance and periphyton richness together explained 76% of the variation observed in the number of prey captured by the bladders. The abundance and richness of periphyton followed the same pattern as phytoplankton, i.e., both increased as dissolved inorganic phosphate concentration rose. This nutrient concentration explained 84 and 74% of the variation observed in richness and abundance of periphyton, respectively. This suggests that abundance and richness of the periphyton associated with U. foliosa depend mostly on environmental conditions rather than on facilitation mechanisms displayed by the plant. In conclusion, if periphyton affects U. folisosa negatively due to the competition for light or nutrients, the plant is “fated to get along with the enemy” but apparently without the capacity to manipulate this “enemy” to its own advantage.

Aquatic Botany, 2006

Investment by bladderwort (Utricularia foliosa L.) in carnivory, in terms of biochemical composit... more Investment by bladderwort (Utricularia foliosa L.) in carnivory, in terms of biochemical composition (carbohydrates per bladder), elemental composition (carbon and nitrogen per bladder), and morphology of the bladders (length, depth, size of the trap door, and size of antennae), was estimated in seven plants located in Yahuarcaca creek (Colombian Amazon) five times from March to May 2005. The aims were to determine whether investment in carnivory varies temporally (over the growing season of the plant) and/or spatially, and if this potential change in carnivory investment varies according to nutrient conditions. The main differences in the investment in carnivory (changes in bladder number and bladder size, and changes in the size of the antennae) were among locations and there were not important differences over the growing season of the plant. Nitrogen and not phosphorus, was the element that stimulated the investment in carnivory. In addition to changes in bladder number and bladder size, we observed a new strategy to enhance prey capture under nitrogen limitation: changes in the size of the antennae. The size of the antennae was approximately 1.3 higher in those plants located in sites with low NO3−. However, we did not observed changes in the carbon/nitrogen ratio of the bladders or in the relationship between bladder length with bladder depth or size of the trap door. The amount of carbohydrates per bladder was also 1.8 higher in those plants located in sites with low NO3− (0.13 μM) than those with higher NO3− concentration (0.39 μM). However, the amount of carbohydrates in the bladder was related with the abundance of periphyton and, hence, it is not possible to conclude that carbohydrate production was a strategy of the plant to enhance the capture of prey. Therefore, our findings do not support the carbohydrate mucilage lure speculations.

Freshwater Biology, 2006

1. We examined the prey captured by individual plants of the tropical carnivorous plant Utricular... more 1. We examined the prey captured by individual plants of the tropical carnivorous plant Utricularia foliosa, located in different areas along a creek in the Colombian Amazon and the zooplankton and macroinvertebrate communities associated with the plants. The aims were: (i) to determine whether bladders of different sizes within each plant catch different numbers of prey or exploit different size ranges and types of prey, (ii) if the quantity and composition of prey captured varies temporally and/or spatially and (iii) if the plant has evolved effective mechanisms of attracting prey. 2. Utricularia foliosa captured the most abundant species of macroinvertebrates associated with the plant. Larger bladders captured more, larger and more diverse prey. However, benefits of the extra prey caught by large bladders were not offset by the greater cost of producing bladders larger than approximately 1650 lm. 3. The number of prey captured was higher in those plants with more carbohydrates per bladder and with a higher ratio of antenna size/bladder length. The antennae enhance capture success by offering the prey a favourable substratum that exploits their natural locomotor and feeding behaviour. However, although carbohydrates may lure prey, carbohydrate production was not a strategy of the plant to enhance the capture of prey, because the amount of carbohydrates in the bladder was related to the abundance of periphyton.

Diatom Research, 2014

This study focuses on the genus Brachysira Kützing from lowland waters as part of the diatom flor... more This study focuses on the genus Brachysira Kützing from lowland waters as part of the diatom flora investigation of Colombia. Periphyton samples were collected in lentic and lotic waterbodies from different Amazonian basins and the Ayapel swamp system in the northern Atlantic plain of Colombia. Diatoms were analysed with light and scanning electron microscopy. Two new taxa, B. guarrerai and B. huitotarum, are described. These species were differentiated from their allied taxa based on the combination of: the shape of the central area; the shape and number of the areolae that delimit the central area; stria position; presence or absence of papillae on the interstriae; and degree of silicification of the ribs that delimit the raphe. In addition, five other taxa are reported and described: B. microcephala (Grunow) Compère and B. subrostrata Lange-Bertalot are recorded for the first time from Colombia, while B. manfredii Lange-Bertalot was previously found in the Sierra Nevada.The other two taxa were identified as B. aff. brebissonii Ross and B. aff. microcephala because the Colombian specimens differ slightly from the type material of these cosmopolitan species.

Aquatic Botany, 2004

Investment by bladderwort (Utricularia foliosa) in carnivory, in terms of total C and N of bladde... more Investment by bladderwort (Utricularia foliosa) in carnivory, in terms of total C and N of bladders per leaf, was estimated in places with different nutrient concentrations from the Yahuarcaca Creek in the Colombian Amazon. The aims were to determine whether nutrient limiting conditions stimulate the investment in carnivory, and the relative balance between C and N invested in carnivory versus C and N obtained from prey. There were no significant differences either for phosphate (PO 4 3À ) concentration or for ammonia (NH 4 + ) concentration among five sampling areas, along approximately 5 km long stretch of the creek, with a pooled mean AE S.D. of 0.19 AE 0.06 and 8.6 AE 3.0 mM, respectively. However, there were significant differences in the nitrate (NO 3 À ) concentration ranging from 0.6 to 2.5 mM. Total C and N of bladders per leaf increased with decreasing NO 3 À . This corroborates the hypotheses that the carnivorous plant U. foliosa optimises its investment in carnivory according to nutrient availability in the water, and that N is a limiting factor that stimulates the investment in carnivory. The numbers of prey per bladder were also higher under NO 3 À limitation, thus enhancing the input of nutrients toward the plant through the bladders. The ratio of total C of prey captured/total C invested in bladders was always lower than 1. However, the efficiency of N was higher since when NO 3 À concentration was lower than 1 mM, the ratio of total N of prey captured/ total N invested in bladders ranged between 0.97 and 1.67. #

El minimalismo surge a finales de la década del 60 en Nueva York, pero sus orígenes están anclado... more El minimalismo surge a finales de la década del 60 en Nueva York, pero sus orígenes están anclados en Europa, en las primeras ideas del arquitecto alemán Ludwig Mies Van Der Rohe, uno de los arquitectos más importantes de este siglo.