Karyotype analysis of three species of Corydoras (Siluriformes: Callichthyidae) from southern Brazil: rearranged karyotypes and cytotaxonomy

The genus Corydoras comprises a diversity of species with different diploid numbers. We compared cytogenetic data among Corydoras species from different rivers of the Ponta Grossa Arch region in southern Brazil. Corydoras ehrhardti and C. aff. paleatus have a similar karyotype formula and the same diploid number (2n = 44). Corydoras lacrimostigmata has a higher diploid number, with 2n = 58 chromosomes. Fluorescence in situ hybridization using 5S and 18S ribosomal DNA probes suggests that these ribosomal DNA sequences are involved in chromosomal rearrangements in these Corydoras species. 5S rDNA is a chromosomal marker that is considered to be unique to the species analyzed in this study. Signals of interstitial telomeric sites are seen in a chromosome pair of C. lacrimostigmata, suggesting chromosomal rearrangements via fusions or translocations. This study revealed that C. ehrhardti and C. aff. paleatus have exclusive chromosomal markers associated with chromosome differentiation, which we speculate to prevent genetic introgression.(AU)

Corydoras compreende um gênero diversificado com espécies de diferentes números diploides. Nós comparamos dados citogenéticos de espécies de Corydoras de diferentes rios da região do Arco de Ponta Grossa no sul do Brasil. Corydoras ehrhardti e C. aff. paleatus tem fórmula cariotípica similar e o mesmo número diploide (2n = 44). Corydoras lacrimostigmata tem um número diploide maior, com 2n= 58 cromossomos. A hibridação in situ fluorescente (FISH) com sondas de DNA ribossomal 5S e 18S sugere que estas sequências de DNA ribossomal estão envolvidas em rearranjos cromossômicos nestas espécies de Corydoras. A marcação do DNAr 5S foi considerada espécie-específico para as espécies analisadas neste estudo. Sinais de sítios teloméricos intersticiais foram vistos em um par de cromossomos de C. lacrimostigmata sugerindo a ocorrência de rearranjos cromossômicos como fusões ou translocações. Este estudo revelou que as espécies C. ehrhardti e C. aff. paleatus têm marcadores cromossômicos exclusivos associados à diferenciação cromossômica, os quais, em nossa hipótese, podem prevenir a introgressão gênica.(AU)

Una nueva subespecie de Heraclides androgeus (Lepidoptera: Papilionidae) y sus aspectos biogeográficos / A new subspecies of Heraclides androgeus (Lepidoptera: Papilionidae) and its biogeographical aspects

Heraclides androgeus epidaurus was described and illustrated by Godman & Salvin in 1890 based on specimens obtained in Veracruz, indicating that their distribution encompassed both the Pacific and Atlantic sides of Mexico. Later authors commented that there were morphological differences between the male wings from both populations. We analyzed, described and nominated Heraclides androgeus reyesorum ssp. nov. Vargas, Llorente & Luis distributed in the Mexican Pacific coast, based on 62 specimens, and compared it with H. a. epidaurus from the Gulf of Mexico, based on more than 200 specimens housed at UNAM: Museo de Zoología, Facultad de Ciencias and the Colección Nacional de Insectos of the Instituto de Biología, as well as some collections from the USA. The main characters were the width of the yellow and black bands on forewings in males, which had a significant difference between the populations of both sides of Mexico, although some characters were variable and showed partial overlap. In the hindwings, the differences were the extent of the subterminal lunules in dorsal and ventral view. We also analyzed the male genitalia, finding notorious differences in both sclerotic processes of the harpe. Subspecific differences between females refer to the brightness and extent of green spots on the hindwings and the extent of lunules in the ventral view. The greatest abundance of H. a. reyesorum ssp. nov. was in the tropical deciduous forest, with gallery forest and in the lower range of the cloud forest, present at altitudes of 500-800m and 1 000-1 750m, respectively. We discussed the pattern of endemism due to historical vicariant processes and explain the presence of the new subspecies of H. androgeus and other taxa of specific level.

Hemos reunido evidencia de que Heraclides está formado por dos subespecies, cada una con caracteres propios que las distinguen; analizamos, describimos y nominamos a Heraclides androgeus reyesorum ssp. nov. que se distribuye en la costa pacífica mexicana. Los principales caracteres masculinos fueron la amplitud de las bandas amarilla y negra en alas anteriores, que al cuantificarse y analizarse tuvieron una diferencia significativa entre las poblaciones de las dos vertientes de México, a pesar que algunos caracteres son variables y muestran superposición parcial. En alas posteriores las diferencias fueron la amplitud de lúnulas subterminales en vista dorsal y ventral. Se analizaron los genitales masculinos, se encontraron diferencias determinantes en los procesos esclerosados del harpagón. Las diferencias subespecíficas entre hembras se refieren al brillo y extensión de las manchas verdes en alas posteriores y a la amplitud de lúnulas en vista ventral. La mayor abundancia de H. a. reyesorum ssp. nov. fue en el bosque de galería del bosque tropical caducifolio y en el intervalo inferior del bosque mesófilo, a 500-800m y 1 000-1 750m, respectivamente. Se discute la existencia de un patrón de endemismo analizado por Halffter (1978) y Morrone & Llorente (2006) que obedece a procesos históricos vicariantes y resume la presencia de subespecies nuevas en el Pacífico como en H. androgeus y muchos otros taxones.

On the origin and diversification of Venezuelan freshwater fishes: the genus Gephyrocharax (Ostariophysi: Characidae) a case study

We conducted a phylogeographic analysis of the genus Gephyrocharax in Venezuela to evaluate geomorphologic evidence for the formation of the country's main watersheds and to establish a biogeographical hypothesis of possible diversification mechanisms of the Neotropical freshwater fish fauna. We assayed eight enzyme systems and general proteins to estimate genetic variability (H, P), intraspecific structuring in several Gephyrocharax valencia and G. venezuelae populations (FIS, FIT, and FST), and a phylogenetic approach for the three species of Gephyrocharax in Venezuela, using Corynopoma riisei as the external group. Fourteen presumptive loci indicate that populations of the three species of Gephyrocharax analyzed show a clear genetic inter-specific differentiation, determined by four loci with fixed alleles (GPI-B*, IDH*, ME-1*, and ME-2*). The resulting cladogram shows two major clades: a monophyletic group consisting of Gephyrocharax n. sp. and G. venezuelae (restricted to the northwest of the country) and a group formed exclusively by G. valencia (distributed along the largest geographic range). Speciation of the Venezuelan lineages of the genus Gephyrocharax could be explained by the origin and course movements of the present Orinoco River together with geomorphologic processes that have occurred in northern Venezuela since the Miocene.

Foi feita uma análise filogeográfica do gênero Gephyrocharax na Venezuela a fim de avaliar as evidências geomorfológicas que levaram à formação dos principais sistemas hidrográficos do país, além de estabelecer uma hipótese biogeográfica com os possíveis mecanismos de diversificação da fauna de peixes de água doce Neotropical. Foram analisados oito sistemas enzimáticos e proteínas gerais para conhecer a variabilidade genética (H, P), estruturação intraespecífica em populações de Gephyrocharax valencia e G. venezuelae (FIS, FIT e FST), e uma abordagem filogenética com base na análise isozimática para as três espécies de Gephyrocharax na Venezuela, com Corynopoma riisei como grupo externo. Quatorze loci presumíveis indicam que as populações das três espécies de Gephyrocharax analisados revelam uma diferenciação inter-específica genética, determinada por quatro loci com alelos fixos (GPI-B*, IDH*, ME-1* e ME-2*). O cladograma resultante apresenta dois clados principais: um grupo monofilético composto por Gephyrocharax n. sp. e G. venezuelae (restrita ao noroeste do país) e um grupo formado exclusivamente por G. valencia (distribuídos ao longo da maior área geográfica). A especiação das linhagens de Gephyrocharax na Venezuela poderia ser explicada pela origem e movimentos do curso atual da bacia do rio Orinoco, associado a processos geomorfológicos que ocorrem no norte da Venezuela desde o Mioceno.

Análisis biogeorráfico de los peces characiformes de Venezuela / Biogeographic Analysis of the Characiformes Fishes of Venezuela

Se realizó un análisis biogeográfico basado en los peces Characiformes de Venezuela con el objetivo de explorar la importancia relativa de los procesos que han contribuido con el establecimiento de los patrones de distribución actuales de la ictiofauna continental venezolana. La información geográfica y filogenética disponible se analizó siguiendo los métodos de Análisis de Parsimonia de Endemismos (PAE) y Análisis de Parsimonia de Brooks (BPA). El PAE señaló fundamentalmente a los Llanos Occidentales y el sur del Amazonas como áreas de endemismo. El BPA realizado con la información filogenética de siete géneros mostró un patrón generalizado con los clados (Caribe + Maracaibo) y ((((Río Negro+Orinoco) + Paria) + Valencia) + Cuyuní), donde se destaca un evento de dispersión desde la cuenca del río Negro hacia el río Orinoco. Los resultados de ambos métodos biogeográficos indican que la región de los llanos - amazonas, donde se conjugó la biota del incipiente Orinoco con la biota amazónica, contiene el mayor número de especies, las áreas de endemismo mejor sustentadas, así como distintos eventos de especiación y posterior dispersión hacia otras regiones. La biota de la región nortecostera del país parece más bien gobernada por procesos de especiación vicariante de carácter puntual por el aislamiento histórico de sus drenajes.

Based on the information available on fishes of the order Characiformes of Venezuela a biogeographical analysis was performed to explore the relative importance of the processes that may have contributed to the establishment of current distribution patterns of the Venezuelan continental ichthyofauna. Geographic and phylogenetic information available for this group of fishes was analyzed by Parsimony Analysis of Endemicity (PAE) and Brooks Parsimony Analysis (BPA). PAE uncovered the western plains and southern Amazonas as areas of endemism. BPA, using the phylogenetic information of seven genera, showed a general pattern with two major clades (Caribbean + Maracaibo) and ((((Rio Negro + Orinoco River) + Paria) + Valencia) + Cuyuní), where the proposed hypothesis highlights a dispersion event from the Rio Negro basin to the Orinoco River. The results indicate that the plains-Amazonas region, where the Amazon biota mixed with that of the incipient Orinoco s biota, contains the largest species richness, areas of endemism, and well as many speciation events with posterior dispersion to other regions of Venezuela. The biota of the northern coastal region in turn seems rather governed by punctual vicariant speciation processes, which may have been conditioned by the historical isolation of the basins draining this region.

Track analysis of the Neotropical Entimini (Coleoptera: Curculionidae: Entiminae)

Track analysis of the Neotropical Entimini (Coleoptera, Curculionidae, Entiminae). Distributional patterns of the species belonging to the tribe Entimini from the Neotropical region were analyzed. Based on a track analysis of 22 species of Entimus, Rhigus, and Phaedropus, for which distributional data were available, two generalized tracks were found. One is located in northern Brazil, corresponding to the Amazonian subregion, and is determined by Phaedropus candidus and Rhigus speciosus. The other is located in southern Brazil, corresponding to the Parana subregion, and is determined by Entimus imperialis, E. excelsus, Phaedropus togatus, Rhigus dejeanii, R. faldermanni, R. horridus, R. lateritus, R. nigrosparsus, and R. tribuloides. The development of the Chacoan subregion is hypothesized to have been the dynamic vicariant event that fragmented the former Amazonian-Parana forest.

Análisis de trazos de Entimini Neotropical (Coleoptera, Curculionidae, Entiminae). Se analizaron los patrones de distribución de la tribu Entimini en la región Neotropical. Con base en un análisis de los trazos de 22 especies de Entimus, Rhigus y Phaedropus, para los cuales se contaba con datos de distribución, se hallaron dos trazos generalizados. Uno se localiza en el norte de Brasil, en la subregión Amazónica, y está sustentado por Phaedropus candidus y Rhigus speciosus. El otro se localiza en el sur de Brasil, en la subregión Paranaense, y está sustentado por Entimus imperialis, E. excelsus, Phaedropus togatus, Rhigus dejeanii, R. faldermanni, R. horridus, R. lateritus, R. nigrosparsus y R. tribuloides. Se hipotetiza que el desarrollo de la subregión Chaqueña constituyó el evento de vicarianza dinámica que fragmentó el antiguo bosque Amazónico-Paranaense.

Inferring possible population divergence in Espeletia pycnophylla (Asteraceae) through morphometric and paleogeographic approaches

The phenotypic structure within and between plant populations is generally influenced by their distribution patterns in space and time; therefore, the study of their divergence is a central issue for the understanding of their microevolutive processes. We boarded the hypothesis that three populations of Espeletia pycnophylla show phenotypic divergence as one of the possible implications of their geographic isolation in the Southern Colombian Andes. We used the Elliptic Fourier Descriptors (leaf shape) and traditional leaf morphometry (leaf size) of 347 leaves to measure inter and intra-population variation and a comparison between a paleogeographic reconstruction with an actual estimate of the distribution areas of E. pycnophylla in order to identify their main changes during the last 14 000 years. The three populations showed significant differences in leaf morphometry and a positive correlation between the matrices of morphometric and geographic dissimilarities, indicating that the inter-population divergence increases between further populations, so that the morphometric structure reflects their spatial distribution. The geographical and paleogeographical estimates evidenced a conspicuous process of reduction and fragmentation of the distribution area of E. pycnophylla since the Late-Glacial until the Holocene. We suggest that these results support possible scenarios of vicariance events, which allow us to approach the divergence of these populations in terms of their historic biogeographic relations. However, genetic analyses are still needed to support these results. Rev. Biol. Trop. 58 (4): 1261-1270. Epub 2010 December 01.

La estructuración fenotípica entre y dentro de poblaciones vegetales responde generalmente a sus patrones de distribución espacio-temporales, por lo tanto, el estudio de su divergencia es un tema central dentro de sus procesos microevolutivos. En esta investigación abordamos la hipótesis que tres poblaciones de Espeletia pycnophylla presentan divergencia fenotípica como uno de los posibles efectos de su aislamiento geográfico en los Paramos del suroeste de Colombia. Utilizamos los Descriptores Elípticos de Fourier (forma foliar) de 117 hojas y algunas medidas morfológicas tradicionales (tamaño foliar) como indicadores de la variación intra e inter-poblacional, además de una comparación entre una reconstrucción paleogeográfica con una estimación del área de distribución actual de la especie para identificar sus principales cambios durante los últimos 14 000 años. Todas las poblaciones mostraron diferencias significativas y además, existió una correlación positiva entre las matrices de disimilitud morfométrica y geográfica, indicando que la divergencia incrementa entre poblaciones lejanas. Paralelamente, las estimaciones geográficas y paleogeográficas evidenciaron un proceso de reducción y fragmentación del área de distribución de E. pycnophylla desde el Tardiglacial hasta el Holoceno. Sugerimos que ambos resultados apoyan escenarios de posibles series de eventos de vicarianza para las poblaciones estudiadas y nos permiten entender su divergencia en términos de sus relaciones biogeográficas históricas.