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16 resultados encontrados para: AUTOR: Kotov, Alexey A.
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1.
Artículo
A phylogenetic analysis of Ilyocryptus Sars, 1862 (Cladocera: Ilyocryptidae)
Kotov, Alexey A. ; Elías Gutiérrez, Manuel (coaut.) ;
Contenido en: International Review of Hydrobiology Vol. 94, no. 2 (May 2009), p. 208-225
Resumen en: Inglés |
Resumen en inglés

Kotov and stifter (2006) revised the taxonomy of the genus Ilyocryptus Sars, 1862 (Branchiopoda: Anomopoda: Ilyocryptidae) and concluded that 28 species can be recognized as valid for the world fauna. In order to test phylogenetic relationships between the species and to contribute to a better understanding of the genus, a cladistic (using branch-and-bound search) analysis was conducted for 25 Ilyocryptus species (two of them with two subspecies). In total, 32 morphological characters were used. An evolutionary-morphological interpretation of the results was also made. Phylogenetic analysis revealed that Ilyocryptus elegans is an earlier derived member of the genus, while other species are separated into two main branches: agilis - and sordidus -lines (without reference to type of moulting). Species with incomplete moulting and species with complete moulting do not form separate clusters, suggesting an independent origin of incomplete moulting within different species groups.


2.
Tesis - Doctorado
Patrones de diversidad y distribución (Real y potencial) de las familias Macrothricidae y Chydoridae (Anomopoda, Cladocera) en México y norte de Centroamérica / Tania Garfias Espejo
Garfias Espejo, Tania ; Elías Gutiérrez, Manuel (tutor) ; Kotov, Alexey A. (asesor) ; Silva Briano, Marcelo (asesor) ; Schmitter Soto, Juan Jacobo (asesor) ;
Chetumal, Quintana Roo, México : El Colegio de la Frontera Sur , 2008
Clasificación: TE/595.320972 / G3
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SIBE Campeche
ECO040003498 (Disponible)
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SIBE Chetumal
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SIBE San Cristóbal
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Resumen en español

A escala global la diversidad biológica se incrementa hacia los trópicos. Un efecto similar ocurre al disminuir la altitud. Las familias Macrothricidae y Chydoridae son grupos de microcrustáceos que destacan por su diversidad en los ambientes acuáticos continentales, lo cual contrasta con el limitado conocimiento de su distribución. Este trabajo establece los patrones de distribución (real y potencial) y la diversidad de estos grupos a distintas escalas de observación en México y norte de Centroamérica. Se elaboró una base de datos a partir de literatura especializada y análisis de material biológico el cuál incluyó información geográfica y ecológica de las especies. Se obtuvo una lista actualizada de estos con ampliaciones de ámbito, nuevos registros y la redescripción de una especie. Se generaron mapas de distribución para estimar: 1) distribución geográfica; 2) diversidad beta o recambio en un gradiente de latitud a escalas 0.5°, 1°, 2°, 4° latitud/longitud; 3) complementariedad para estimar la similitud faunística entre provincias biogeográficas; 4) Cuadros complementarios (CC) para establecer criterios de conservación y 5) distribución potencial con el método GARP (Genetic Algorithm for Rule set Prediction). Se registraron 61 especies, 2 subgéneros y 28 géneros, se agregó un nuevo registro para la región (Alona glabra) y se amplió el ámbito de distribución del 54% de las especies.

Se redescribió a Macrothrix agsensis con base en los distintos estadios de desarrollo y se reasignó el macho pues anteriormente fue confundido con M. smirnovi. La distribución espacial de los grupos fue variable y mostró fuertes contrastes de latitud y altitud. Por el momento no se puede definir si los organismos con distribución amplia forman poblaciones estables o solo sobreviven un tiempo y luego desaparecen. En general, los macrotrícidos incrementaron su diversidad hacia las montañas y la disminuyeron hacia los trópicos; en cambio los quidóridos incrementaron su diversidad hacia el sur de la porción central del altiplano mexicano y la disminuyeron al sur, lo cual es opuesto al gradiente de diversidad general que predice un incremento gradual de las especies hacia los trópicos. El recambio fue mayor en las provincias biogeográficas Altiplano y Eje Neovolcánico en macrotrícidos y el Golfo de México en quidóridos. Las provincias más complementarias fueron Eje Neovolcánico en macrotrícidos y en quidóridos Altos de Chiapas y Belice. Las provincias menos complementarias fueron Guatemala y Altos en macrotrícidos y las provincias Costa del Pacífico y Petén en quidóridos. Para representar la totalidad de los macrotrícidos en las provincias biogeográficas es necesario proteger de 2 a 3 CC. Para los quidóridos deben protegerse de 1 a 9 CC. El 52% de los modelos de distribución potencial resultaron significativos (X²; P < 0.05).

Los modelos ampliaron en teoría el área de distribución de los organismos dentro y fuera del área de estudio. Por esta razón, es probable que el número de posibles endemismos sea menor al conocido. Los puntos con distribución potencial restringida podrían representar sitios donde las condiciones ambientales de temperatura y precipitación son muy específicas. Se puede especular que estos sitios podrían albergar especies crípticas o bien representar el límite de distribución de algunas especies. De acuerdo a los modelos es posible que algunas especies ocupen las planicies costeras y algunas regiones montañosas como corredores naturales. En apariencia, la penetración de formas norteñas hacia el sur es en forma de cuña, mientras los taxa neotropicales avanzan hacia el norte principalmente a través de las planicies costeras. Deben ampliarse los muestreos principalmente en latitudes elevadas para apoyar las hipótesis aquí presentadas. El modelar con tres o menos registros no generó predicciones adecuadas en 25% de las especies. En la práctica, los modelos de predicción potencial pueden ser útiles en la generación de hipótesis, orientación y planeación de proyectos que deben comprobarse con trabajo de campo.

Resumen en inglés

The Macrothrix rosea-triserialis group of species (Cladocera: Macrothricidae) is characterized by (1) a well developed postabdomen heel; (2) rows of strong spines on preanal margin of postabdomen and (3) scraper 5 of limb II with enlarged subapical teeth. Macrothrix agsensis, a member of this group, was recently described from the Mexican Central Plateau based on parthenogenetic females only. It is characterized by five rows of long spines in the female antenna I, and five thick spines on setae 4–5 of endite 2 of limb I. Here we describe its ephippial females and males, as well as development of the latter. The ephippium is strongly chitinized, with a special ornamentation in the form of hexagonal cells. The male is characterized by peculiar groups of long and short spinules in the anterior half of the antenna I, three furrows with spinules on the male copulatory hook on limb I, and a longer seta in the outer distal lobe, armed with bean-like projections. With regard to the known distribution of Macrothrix in Mexico, it is now feasible to consider the existence of four possible endemic species in this region: Macrothrix mexicanus, M. agsensis, M. sierrafriatiensis and M. marthae.

All of them, except the last one, are restricted to the Central Plateau. Another species, Macrothrix smirnovi, was described from Mexico and later found in Sacramento (USA). Among the widespread species are Macrothrix elegans and M. spinosa, the former one of the most common macrothricids in the Neotropics. It shows a northern distributional limit at the northwest of Mexico and it is possible to find it from north to south. Macrothrix hirsuticornis, restricted to North America has a southern limit in the north. Macrotrhix spinosa is found from north to south of Mexico, but its distribution range extends to South America. Other old records are doubtful, such as Macrothrix triserialis, M. rosea and M. laticornis, because they seem to be restricted to the old world.

Índice

Resumen
Introducción
Material y Métodos
Resultados
Discusión
Conclusiones
Bibliografía
Figuras
Cuadros
Anexos


3.
Artículo
*Solicítelo con su bibliotecario/a
Cladocera (Crustacea: Ctenopoda, Anomopoda) from southern Mexico, Belize and northern Guatemala, with some biogeographical notes
Elías Gutiérrez, Manuel ; Kotov, Alexey A. (coaut.) ; Garfias Espejo, Tania (coaut.) ;
Contenido en: Zootaxa No. 1119 (Jan 2006), p. 1–27 ISSN: 1175-5334
Nota: Solicítelo con su bibliotecario/a
Resumen en: Inglés |
Resumen en inglés

Different surveys in the Campechano–Petenense biogeographical province, including a part of Yucatan Peninsula, Belize, and North of Guatemala (Departments of Peten and Alta Verapaz), produced a list of 56 species of the Cladocera. Studied water bodies included small temporary pools, sinkholes (named cenotes), permanent lagoons, wetlands, and Peten Lake. We increase the number of known cladoceran species from Mexico by adding eight new records, and provide the first published species list for Belize, as well as for the Mayan Mountains and intermittent rivers from Guatemala. Interesting taxa found are Diaphanosoma bergamini Paggi & da Rocha, 1999; Macrothrix spinosa King, 1853; M. elegans Sars, 1901; Grimaldina brazzai Richard, 1892; Picripleuroxus quasidenticulatus Smirnov, 1996; Ephemeroporus tridentatus (Bergamin, 1939); Graptoleberis sp.; Alona cf. ossiani Sinev, 1998; Oxyurella ciliata Bergamin, 1939, and O. longicaudis (Birge, 1910). The majority of these species are Neotropical representatives, and the Mexican records are the northernmost. Few other taxa, such as the recently described Leydigia louisi mexicana Kotov, Elías-Gutiérrez & Nieto, 2003, are related to African species or widely distributed, like Ilyocryptus spinifer Herrick, 1882. Some species, as E. tridentatus (Bergamin) and O. ciliata Bergamin were rare in the samples.


4.
Artículo
*Solicítelo con su bibliotecario/a
Ecological remarks on Mastigodiaptomus nesus, Bowman 1986 (Copepoda, Calanoida) in a Mexican karstic sinkhole
Cervantes Martínez, Adrián (coaut.) ; Elías Gutiérrez, Manuel (coaut.) ; Gutiérrez Aguirre, Martha Angélica (coaut.) ; Kotov, Alexey A. (coaut.) ;
Contenido en: Hydrobiologia Vol. 542, no. 1 (July 2005), p. 95-102 ISSN: 0018-8158
Nota: Solicítelo con su bibliotecario/a
Resumen en: Inglés |
Resumen en inglés

Mastigodiaptomus nesus (Bowman, 1986) was previously described from the West Indies, and its distribution was considered restricted to these islands. Recently it has been detected in several systems from the continental Yucatan Peninsula in Mexico. In this study, we contribute to the body size variability, abundance, distribution and vertical migration of Mastigodiaptomus nesus dwelling in a small, deep (264 m2, 47 m deep) karstic beaker-shaped sinkhole, located in this Peninsula. Here, this species is an important component of the zooplankton community during all the year. We analyzed the relationship between its abundance and concentration of nutrients (NO)3), and Chlorophyll a. Differences in body size by sex (F ¼ 67.56, p < 0.0001; n ¼ 180), and sampled season (F ¼ 6.59, p < 0.01; n ¼ 180) were found. When animals from this sinkhole were compared with other localities, size difference was detected. Bigger animals were found in the West Indies, and smaller ones in continental localities.

The nauplii were the most abundant development instars, followed by copepodids, and adults. In general, all developmental instars had a normal migration, with higher abundance at night time in upper layers (0.5 and 5 m), and diminishing towards daylight time. Direction of migrations seems to be towards the walls of the sinkhole (horizontal migration) instead of the deeper water layers, suggesting that these copepods are hidden in the irregular calcareous walls of the sinkhole. Abundance of total copepodid developmental stages were correlated with the Chl-a concentration. In addition, we found a highly significant difference between Chl-a concentration (F ¼ 24.172, p < 0.001, n ¼ 72), and NO)3 concentration at all strata among seasons (F ¼ 25.46, p < 0.001, n ¼ 60). Our results suggest that the body size of M. nesus is influenced by the nutrient concentration, and its vertical abundance and distribution may be explained by food availability.


5.
- Artículo con arbitraje
*En hemeroteca, SIBE-Chetumal
Moina dumonti sp. nov. (cladocera, anomopoda, moinidae) from southern Mexico and Cuba, with comments on moinid limbs
Kotov, Alexey A. ; Elías Gutiérrez, Manuel (coaut.) ; Granados Ramírez, José G. (coaut.) ;
Clasificación: AR/595.3 / K6
Contenido en: Crustaceana Vol. 78, no. 1 (2005), p. 41-57 ISSN: 0011-5403
Nota: En hemeroteca, SIBE-Chetumal
Resumen en español

Una nueva especie, Moina dumonti sp. nov. ( Branchiopoda, Anomopoda,Moinidae) se encuentra en el sureste deMéxico y Cuba. Esta especie está relacionada con Moina reticulata por las siguientes características: (1) cuerpo relativamente comprimido lateralmente; (2) la cámara embrionaria de los adultos grandes se encuentra ligeramente inflada, como resultado el dorso de las valvas es ligeramente convexo; (3) la presencia de un ocelo; (4) no presenta pelos en la cabeza y las valvas; (5) tiene un solo huevo en el efipio; (6) los gonoporos se encuentran en posición dorso-distal en el macho. Se enlistan las diferencias de M. dumonti sp. nov. con respecto a otros miembros del grupo M. reticulata y algunas especies cercanas. Finalmente, se incorporan una serie de comentarios sobre la morfología de los apéndices torácicos de los moinidos.

Resumen en inglés

A new species, Moina dumonti sp. nov. (Branchiopoda, Anomopoda, Moinidae) is found in southern Mexico and Cuba. This species is closely similar to Moina reticulata, because of (1) body rather laterally compressed; (2) brood pouch in large adults slightly inflated, as a result dorsum of valves only slightly convex; (3) presence of an ocellus; (4) no hairs on head and valves; (5) a single egg in the ephippium; (6) gonopores in male positioned dorso-distally. Differences of M. dumonti sp. nov. with other members of the M. reticulata-group, and some other closely similar species, are listed. Comments are given on the morphology of the limbs in moinids.


6.
Artículo
Notes on aloninae Dybowski & grochowski, 1894 amend. Frey, 1967 (Cladocera: anomopoda: chydoridae): 2. Leydigia cf. Striata birebén, 1939 in South Mexico
Kotov, Alexey A. ; Elías Gutiérrez, Manuel (coaut.) ;
Contenido en: Arthropoda Selecta Vol. 13, no. 1-2 (2004), p. 1-6 ISSN: 0136-006X

7.
- Artículo con arbitraje
Separation of two neotropical species: Macrothrix superaculeata (Smirnov, 1982) versus M. elegans Sars, 1901 (Macrothricidae, Anomopoda, Cladocera)
Kotov, Alexey A. ; Garfias Espejo, Tania (coaut.) ; Elías Gutiérrez, Manuel (coaut.) ;
Contenido en: Hydrobiologia Vol. 517, no. 1 (April 2004), p. 61-88 ISSN: 0018-8158
Resumen en: Inglés |
Resumen en inglés

The morphology of two Neotropical taxa, Macrothrix elegans Sars, 1901 and M. superaculeata (Smirnov, 1982) (Macrothricidae, Anomopoda, Cladocera) was redescribed, based on type materials (a lectotype of M. elegans was selected here), and additional samples from the Americas. Previous conclusion about synonymy of both species was erroneous, because it was based on limited material from South America. M. superaculeata differs from M. elegans in the presence of a sharp spine at postero-dorsal angle of valves; a more fine ring around dorsal head pore; thinner hexagonal reticulation of valves; the presence of setules on basal segment of postabdominal seta; armature of exopod on antenna II, and some features of thoracic limbs. Previously, the discriminative features of the two species were not formulated accurately, and it was a reason of several misidentifications. Actually, M. superaculeata is found only in a limited set of localities from the Amazon basin, while M. elegans is one of the most common anomopod species in all Neotropics, from Argentina to Mexico.


8.
- Artículo con arbitraje
Differentiation between african leydigia ciliata Gauthier, 1939 and Neotropical L. cf. striata Birabén, 1939 (Chydoridae, anomopoda, cladocera)
Kotov, Alexey A. (autor) ; Damme, Kay Van (autor) ; Elías Gutiérrez, Manuel (autor) ;
Clasificación: AR/595.32 / K67
Contenido en: Hydrobiologia Vol. 505, no. 1-3 (September 2003), p. 179-197 ISSN: 0018-8158
Bibliotecas: San Cristóbal
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ECO010006633 (Disponible)
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Resumen en: Inglés |
Resumen en inglés

We investigated the morphology and variability of Leydigia ciliata Gauthier, 1939 (Chydoridae, Anomopoda, Cladocera) from Africa and of Leydigia cf. ciliata from the Americas, using optical microscope and SEM. Some differences, predominantly in limb armature, between African and Neotropical populations were revealed. Probably, the name L. striata Birabén, 1939 must be used for Neotropical populations, but this opinion must be confirmed by re-examination of topotypical material (Puerto de La Plata, Argentina). The confused situation in the systematics of the Leydigia acanthocercoides-ciliata complex is confirmed and some characters previously applied to the discrimination of L. ciliata Gauthier, 1939 from L. acanthocercoides (Fischer, 1854), are discussed.


9.
Artículo
Leydigia louisi louisi jenkin, 1934 in the neotropics, L. louisi mexicana n.subsp. in the Central Mexican highlands
Kotov, Alexey A. ; Elías Gutiérrez, Manuel (coaut.) ; Nieto López, María Guadalupe (coaut.) ;
Clasificación: AR/595.320972 / K6
Contenido en: Hydrobiolgia Vol. 510, no. 1-3, (December 2003), p. 239-255
Bibliotecas: San Cristóbal
Cerrar
SIBE San Cristóbal
ECO010006272 (Disponible)
Disponibles para prestamo: 1
Resumen en: Inglés |
Resumen en inglés

Leydigia louisi Jenkin, 1934 was recently redescribed by Kotov (2003). We found in Guatemala and South of Mexico populations of this species, similar with the typical African form. A re-examination of Daday's (1902) specimens from Patagonia demonstrated that his material, determined as L. leydigi, was also L. louisi. At the same time, we describe a new subspecies Leydigia louisi mexicana n.subsp. from four water bodies on the central Mexican plateau (State of Mexico). Parthenogenetic females, ephippial females, juvenile and adult males are described. SEM illustrations are given for L. louisi mexicana n.sp. It differs from the nominotypical subspecies by (1) ocellus of irregular shape; (2) chitinous insertions within distal segments of swimming setae far from bases of segments; (3) on IDL, 3 bunches of very long setules; (4) setules on distal lobe of limb II long; (5) longest seta of exopodite III with long, fine setules; (6) seta 1 of exopodite IV relatively short; (7) a two-lobed body on inner margin of limb V. Features 2–6 were never used in the genus previously, but were applied in the systematics of other genera of Chydoridae. The ranges of these two subspecies are, probably, the Neotropical and Holarctic regions.


10.
Artículo
Separation of Leydigia louisi Jenkin, 1934 from L. leydigi (Schoedler, 1863) (Chydoridae, Anomopoda, Cladocera)
Kotov, Alexey A. ;
Contenido en: Hydrobiologia Vol. 490, no. 1-3 (January 2003), p. 147-168 ISSN: 0018-8158
Resumen en: Inglés |
Resumen en inglés

The aim of the present article was to contribute to the systematics of the leydigi-like species of Leydigia consisting of a few (probably 3) formal species with: (1) a large basal spine on the postabdominal claw (as long as claw thickness at the base); (2) a short setulation at anterior margin of labral keel; (3) no longitudinal striation on the female valves; (4) at least three lateral setae in each fascicle on the postabdomen; (5) three large lateral setae on exopodite III. The morphology of L. leydigi (Schoedler, 1863) and L. louisi Jenkin, 1934 are redescribed, and type material of L. macrodonta Sars, 1916 is studied. In contrast to previous suggestions (Jenkin, 1934; Smirnov, 1971), I found that: (1) L. louisi is a valid species, not a subspecies of L. macrodonta; (2) L. macrodonta is not a member of the L. leydigi-group. The third member of leydigi-group, Leydigia macrodonta longiseta Chen Shou-zhong, 1992, was described from China. It is not a subspecies of L. macrodonta, but a relative of L. leydigi; most probably, it is a valid species, but this opinion must to be confirmed by examination of original Asian material. In this article, the presence of L. leydigi in Palearctic only, and that of L. louisi in only Africa was confirmed. A new subspecies of L. louisi, found in Mexico, will be reported separately.