188 research outputs found
Una visión general de la taxonomía de Attalea (Arecaceae)
The genus Attalea (Arecaceae) is distributed in continental habitats of the Neotropical region and in some Caribbean islands. Life forms of Attalea species vary from small acaulescent palms to tall and massive palms, always solitary. The ecological range of the genus encompasses most of the Neotropical ecosystems, from coastal sand dunes to sub-Andean forests up to 1600 m in elevation, lowland wet to dry forests, savannas, swamps, etc. The taxonomy of the genus has been poorly understood due to conflicting genus and species concepts that exist since the last decades. Taxonomical problems have been caused by the lack of adequate material, especially species of large size, loss of many types and difficulties in interpreting hybrids. In this article, I review the most recent taxonomic literature on Attalea. The number of species in Attalea varies from 29 to 67 depending on different authors, with a maximum estimate of 73 species when combining the revised publications. There is a consensus for the validity of 20 species among modern palm taxonomists. The most conflicting species or group of species are discussed in detail as well as the taxonomic significance of some characters such as the pattern of insertion of staminate flowers on rachillae, insertion of pinnae on rachis, and arrangement of fibrous strands in the endocarp.Attalea (Arecaceae) es un género distribuido en toda la región Neotropical continental y en algunas islas Caribeñas. Las formas de vida de las especies de Attalea incluyen tanto pequeñas palmeras como plantas de gran tamaño, siempre con tallo solitario. El rango ecológico del género abarca prácticamente todos los ecosistemas neotropicales desde las dunas de arena costeras hasta el bosque sub-Andino (algunas especies llegan a 1600 m de altitud), pasando por todo tipo de bosque tropical, seco o húmedo, pantanos, sabanas, etc. La taxonomía del género ha sido poco entendida y conceptos conflictivos sobre géneros y especies existen desde hace décadas. Las dificultades taxonómicas resultan de la falta en los herbarios de material adecuado, en particular para las grandes especies, de la pérdida o destrucción de numerosos tipos y de la frecuente hibridación entre especies. En este artículo se analizan los trabajos taxonómicos más recientes sobre Attalea. El número de especies varía entre 29 y 67 según los autores, y un máximo estimado de 73 especies al combinar los diferentes trabajos; siendo 20 las especies en consenso entre autores. Las especies y grupos de especies más problemáticos se tratan detalladamente y se enfatiza el significado taxonómico de algunos caracteres como la inserción de las flores estaminadas en la raquilla, inserción de las pinas en el raquis, distribución de las fibras en el endocarpio, entre otros
Phylogenetic relationships of andean-ecuadorian populations of Anastrepha fraterculus (Wiedemann 1830) (Diptera : Tephritidae) inferred from COI and COII gene sequences
Abstract. Phylogenetic relationships among Andean-Ecuadorian and other Neotropical populations of Anastrepha fraterculus and related species have been studied using two regions of mtDNA : 405 base pairs within Cytochrome Oxidase I ( COI) and 224 base pairs within Cytochrome Oxidase II (COII). Phylogenetic relationships were inferred using Maximun Parsimony (MP) method and haplotype networks. Andean-Ecuadorian populations of A. fraterculus are monomorphic at the COI locus and fall within a clade of South-American lowland populations of A. fraterculus. They appear to be unrelated with populations of northern Andes of Colombia and Venezuela also assigned to A. fraterculus, meaning that this species, as currently circumscribed, is not monophyletic and is composed of different biological entities that are little differentiated morphologically. At the COII locus, AndeanEcuadorian populations of A. fraterculus show a major haplotype with a few variants, and form a clade with the lowland populations of southern Brazil an Argentina, but are clearly differentiated from them. Andean-Ecuadorian populations of Anastrepha fraterculus appear to be homogeneous with respect to their mitochondrial genome and thus their identity as members of a single gene pool is confi rmed by these results. Résumé. Relations phylogénétiques entres les populations des Andes d'Equateur d'Anastreph
El género Hexopetion Burret (Arecaceae)
The genus Hexopetion was described by Burret to accommodate a single species, H. mexicanum. We reinstate the genus on the basis of morphological and anatomical data, and enlarge it to include a second species, Astrocaryum alatum, for which a new combination is made.El género Hexopetion definido por Burret con una única especie, H. mexicanum, se restablece a partir de datos morfológicos y anatómicos. Se incluye una segunda especie, Astrocaryum alatum, para la cual se hace una nueva combinación
Taxonomic status of Oenocarpus bataua (Euterpeae, Arecaceae) inferred from plastid sequences
With the aim of testing the evolutionary relationships between Oenocarpus bataua (formerly Jessenia bataua) and other Oenocarpus species (Arecaceae), a phylogenetic study of tribe Euterpeae (Arecaceae) was conducted using 3,6 kb of non-coding chloroplast DNA sequence data. The results of maximum parsimony analysis support the monophyly of Euterpeae and the inclusion of O. bataua within the Oenocarpus clade. Our results show substantial molecular divergence between O. bataua var. bataua and var. oligocarpus suggesting that, according to their original description, these two taxa may indeed represent different species. However, our phylogenies should be considered as tentative due to low statistical support
Evaluación detallada de la distribución de Astrocaryum sec. Huicungo (Arecaceae) en Perú
Detailed distribution of Astrocaryum sect. Huicungo (Arecaceae) in Peru is presented and discussed. Twelve out of the 15 species that compose this section are found in the Peruvian territory from North to South in the eastern Andean foothills and western Amazonian lowlands. All these species have a parapatric distribution, except for Astrocaryum macrocalyx and A. urostachys, which share a very limited area. Limits of distribution areas may be related to geographical, geomorphological and ecological barriers (river, geological rising, soil drainage). In some cases, however, the contact between species is almost contiguous; no natural barrier could be detected in the field.Se presenta y se discute la distribución detallada de las especies de Astrocaryum sect. Huicungo (Arecaceae) en Perú. Doce de las 15 especies que componen esta sección se encuentran en el territorio peruano, del Norte al Sur en el piedemonte de los Andes orientales y en la llanura amazónica. Todas las especies presentan una distribución parapátrica, salvo Astrocaryum macrocalyx y A. urostachys que se superponen en una franja muy reducida. Las áreas de distribución son separadas por pasillos estrechos, que se pueden relacionar a barreras geográficas, geomorfológicas y ecológicas (ríos, levantamientos geológicos, drenaje del suelo). En algunos casos, las especies se suceden en el espacio sin que se haya podido identificar barreras naturales separándolas
Caracterización de una zona de contacto parapátrico entre Astrocaryum macrocalyx y Astrocaryum urostachys en el límite entre la planicie Marañón-Pastaza y el Arco de Iquitos
This study identifies a parapatric contact zone between Astrocaryum macrocalyx and Astrocaryum urostachys at the boundary between the Marañón-Pastaza flood plain and the Iquitos Arch, in the northern Peruvian Amazon. The area sampled covers 35,5 ha in the form of 9 transects 1-3 km long × 20 m wide. All Astrocaryum individuals were recorded within the transects, and their size was measured as well as topographical data of the environment. The results show that the two species meet only in a small area in the confluence zone of Marañón and Tigre rivers near the southwest basement of the Iquitos Arch. A total of 1133 Astrocaryum individuals were recorded, mostly in the 0—3,90 m size classes, with only 9,2% of the individuals exceeding 12 m in high. Within the three topographical positions considered (slope, valley bottom and ridge), most individuals were found in the lower slopes and bottoms of valleys.Se determinó una zona de contacto parapátrico entre Astrocaryum macrocalyx y Astrocaryum urostachys en el límite entre la planicie Marañón-Pastaza y el Arco de Iquitos, en la Amazonía norperuana. Para ello se realizó un muestreo de 35,5 hectáreas. Esta área de estudio se dividió en 9 transectos con dimensiones de 1 a 3 km por 20 m de ancho. Se tomaron datos de abundancia, altura de la planta y variaciones topográficas a lo largo de los transectos. Los resultados indican que estas especies entran en contacto solamente en una pequeña área en la zona de confluencia de los Ríos Marañón y Tigre en la margen suroccidental del arco de Iquitos. Durante la evaluación se registró un total de 1133 individuos del género Astrocaryum. La mayoría de individuos (58,5%) se ubican en las clases de tamaño inferiores (0—3,90 m de alto) mientras que los individuos mayores a 12 m representan 9,2% de los individuos censados. En las tres posiciones topográficas (pendientes, valles y colinas) la mayor cantidad de individuos están presentes en las laderas y en los zonas bajas de las colina
Characterization of a parapatric contact zone between Astrocaryum macrocalyx and Astrocaryum urostachys at the boundary of the Marañón-Pastaza flood plain and the Iquitos arch
This study identifies a parapatric contact zone between Astrocaryum macrocalyx and Astrocaryum urostachys at the boundary between the Marañón-Pastaza flood plain and the Iquitos Arch, in the northern Peruvian Amazon. The area sampled covers 35,5 ha in the form of 9 transects 1-3 km long × 20 m wide. All Astrocaryum individuals were recorded within the transects, and their size was measured as well as topographical data of the environment. The results show that the two species meet only in a small area in the confluence zone of Marañón and Tigre rivers near the southwest basement of the Iquitos Arch. A total of 1133 Astrocaryum individuals were recorded, mostly in the 0—3,90 m size classes, with only 9,2% of the individuals exceeding 12 m in high. Within the three topographical positions considered (slope, valley bottom and ridge), most individuals were found in the lower slopes and bottoms of valleys
На перетині двох світів: Волинь в умовах українського національно-визвольного руху 1940-х років
У статті йдеться про особливості національно-визвольного руху періоду Другої світової війни у двох регіонах Волині — східному (Житомирщина) та західному. Розглядається проблема ставлення населення Східної Волині до оунівського підпілля і УПА в 1941—1945 рр. та масштаби залученості у них місцевих мешканців.The peculiarities of national liberation movement in the period of the Second World War on the territory of two regions of Volyn — eastern (Zhytomyr region) and western are described in the article. The problem of the attitude of people of eastern Volyn to OUN underground and UPA in 1941—1945 years and the measure of involvement of local people in these organizations are examined
Floral structure and development in the monoecious palm Gaussia attenuata (Arecaceae; Arecoideae)
Background and Aims Sexual dimorphism, at both the flower and plant level, is widespread in the palm family (Arecaceae), in contrast to the situation in angiosperms as a whole. The tribe Chamaedoreeae is of special interest for studies of the evolution of sexual expression since dioecy appears to have evolved independently twice in this group from a monoecious ancestor. In order to understand the underlying evolutionary pathways, it is important to obtain detailed information on flower structure and development in each of the main clades. Methods Dissection and light and scanning electron microscopy were performed on developing flowers of Gaussia attenuata, a neotropical species belonging to one of the three monoecious genera of the tribe. Key Results Like species of the other monoecious genera of the Chamaedoreeae (namely Hyophorbe and Synechanthus), G. attenuata produces a bisexual flower cluster known as an acervulus, consisting of a row of male flowers with a basal female flower. Whereas the sterile androecium of female flowers terminated its development at an early stage of floral ontogeny, the pistillode of male flowers was large in size but with no recognizable ovule, developing for a longer period of time. Conspicuous nectary differentiation in the pistillode suggested a possible role in pollinator attraction. Conclusions Gaussia attenuata displays a number of floral characters that are likely to be ancestral to the tribe, notably the acervulus flower cluster, which is conserved in the other monoecious genera and also (albeit in a unisexual male form) in the dioecious genera (Wendlandiella and a few species of Chamaedorea). Comparison with earlier data from other genera suggests that large nectariferous pistillodes and early arrest in staminode development might also be regarded as ancestral characters in this trib
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