Trophic morphology and diet of the endangered fish Tlaloc hildebrandi (Cyprinodontiformes: Profundulidae) / Morfología trófica y dieta de Tlaloc hildebrandi (Cyprinodontiformes: Profundulidae), especie amenazada de extinción

Abstract Introduction: Tlaloc hildebrandi is a freshwater killifish, endemic to Southern Mexico and under threat of extinction; the knowledge of the trophic morphology and diet is needed by conservation managers. Objective: To analyse and describe the anatomy of the visceral skeleton, visceral musculature, digestive tract and its adjoining glands of T. hildebrandi; as well as its diet. Methods: We performed the trophic anatomy on 20 adult specimens of both sexes, through manual dissection; as well as gut content analysis in 60 individuals to describe the diet. Results: As notable characters of the visceral skeleton of T. hildebrandi we found the posterior notch of the premaxillary, the presence of the "coronoid cartilage", the tricuspid shape of the gill rakers of the first branchial arch, and the presence of the coronomeckelian bone; some outstanding characters of the visceral musculature are the origin of the retractor dorsalis muscle from the first four vertebral centra, and the division of the pharyngoclavicularis externus muscle into two sections. The notable characters of the digestive tube are the absence of stomach and pyloric caeca, and the presence of the "intestinal valve". Insects (IVI = 66.6 %) and ostracods (13 % IVI) were the dominant prey items of the Tlaloc hildebrandi diet; larvae and adults of the family Chironomidae were the most dominant insects in the diet (53 % IVI). Conclusions: The organization of the digestive system of T. hildebrandi corresponds to the general morphologic pattern of the Cyprinodontiformes; however, we register as new information for these fish, the presence of the "coronoid cartilage" and the "intestinal valve". The structures of the trophic morphology and the components of the diet, confirms us that T. hildebrandi is a carnivorous-insectivorous fish.

Resumen Introducción: Tlaloc hildebrandi es un killi de agua dulce, endémico del sur de México y bajo amenaza de extinción; el conocimiento de la morfología trófica y la dieta son necesarios para los administradores de la conservación. Objetivo: Analizar y describir la anatomía del esqueleto visceral, la musculatura visceral, el tracto digestivo y las glándulas adyacentes de T. hildebrandi; así como los componentes de su dieta. Métodos: Mediante la técnica del descarnado manual, realizamos la descripción de la anatomía trófica en 20 especímenes adultos de ambos sexos, y el análisis del contenido estomacal en 60 individuos para describir la dieta. Resultados: Como caracteres sobresalientes del esqueleto visceral de T. hildebrandi está la escotadura posterior del premaxilar, la presencia del "cartílago coronoides", la forma tricúspide de las branquiespinas del primer arco branquial y la presencia del hueso coronomeckeliano; como caracteres de la musculatura visceral sobresalen el origen del músculo retractor dorsalis de los cuatro primeros centros vertebrales, y la división del músculo pharyngoclavicularis externus en dos secciones. Los caracteres notables del tubo digestivo son la ausencia de estómago y de ciegos pilóricos y la presencia de la "válvula intestinal". Los insectos (IVI = 66.6 %) y ostrácodos (13 % IVI) fueron los componentes dominantes de la dieta de T. hildebrandi; particularmente las larvas y adultos de la familia Chironomidae fueron los insectos más abundantes en la dieta (53 % IVI). Conclusiones: La organización del sistema digestivo de T. hildebrandi corresponde al patrón morfológico general de los Cyprinodontiformes, sin embargo, se registra como nueva información para estos peces, la presencia del cartílago coronoides y la válvula intestinal. Las estructuras de la morfología trófica y los componentes de la dieta nos confirman que T. hildebrandi es un pez carnívoro-insectívoro.

Reproductive cycle of native viviparous fish species (Actinopterygii: Cyprinodontiformes: Goodeidae) in a subtropical Mexican lake

Reproductive tactics and strategies contribute to the persistence and maintenance of long-term populations in fish species. Members of the subfamily Goodeinae are a group of small-bodied freshwater fish with specialized reproduction (viviparity-matrotrophy). They are found in the highlands of central Mexico, most of them endemic. The aim of this study was to conduct a comprehensive investigation to evaluate the annual reproductive cycle of seven species of goodeines (splitfins). We carried out our study in the subtropical Lake Zacapu, Mexico, with bi-monthly sampling from May 2019 to March 2020. We obtain the fertility, size at first maturity (L50), sex ratio, and gonadosomatic index. Our result shows that populations of goodeines have high fertility compared to other populations of the same species in other aquatic systems and also to other species of goodein. We found that males mature at smaller sizes than females, the observed proportion of females was greater than males in all the goodeines. Lake Zacapu goodeines have two reproductive peaks, one in spring (April to June) and another in fall (September to November). These tactics (fertility rates, sex ratio, reproductive period) and strategies (viviparity-matrotrophy) favor reproductive success in this environmentally stable subtropical lake in the highlands of Mexico.(AU)

Las tácticas y estrategias reproductivas contribuyen a la persistencia y el mantenimiento de las poblaciones a largo plazo en especies de peces. Miembros de la subfamilia Goodeinae son un grupo de peces de agua dulce con reproducción especializada (viviparidad-matrotrofia). Se encuentran en el centro de México, la mayoría de ellos endémicos. El objetivo de este estudio fue realizar una investigación integral para evaluar el ciclo reproductivo anual de siete especies de goodeines o mexclapiques. Realizamos nuestro estudio en el lago subtropical de Zacapu, México, con muestreo bimestral de mayo de 2019 a marzo de 2020. Nuestros resultados muestran que las poblaciones de goodeines tienen una alta fertilidad en comparación con otras poblaciones de la misma especie en otros sistemas acuáticos y también con otras especies de goodeines. Encontramos que los machos maduran en tamaños más pequeños que las hembras, la proporción observada de hembras fue mayor que los machos en todas las goodeines. Los goodeines del lago Zacapu tienen dos picos reproductivos, uno en primavera (abril a junio) y otro en otoño (septiembre a noviembre). Estas tácticas (fertilidad, proporción de sexos, período reproductivo) y estrategias (viviparidad-matrotrofia) favorecen el éxito reproductivo en este lago subtropical ambientalmente estable en el altiplano de México.(AU)

Descripción morfológica e histológica del tejido hepático de Gambusia holbrooki (Pisce: Poeciliidae) que habita en la Provincia de Arica - Chile / Morphological and histological description of the liver tissue of Gambusia holbrooki (Pisce: Poeciliidae) inhabiting the Province of Arica - Chile

Gambusia holbrooki es el pez de agua dulce con mayor distribución en Chile y el mundo, pero los estudios que abordan la morfología e histología hepática del pez son escasos. El hígado es utilizado para evidenciar efectos subletales de contaminantes ambientales y es preciso contar con una descripción histomorfológica del hígado para futuros estudios comparativos. El presente estudio tiene como objetivo describir patrones histomorfológicos del hígado de Gambusia holbrooki, para ello se colectaron 97 individuos adultos de los sistemas límnicos de los valles de Lluta y Azapa (Extremo norte de Chile), para observar patrones morfológicos comunes en ambas poblaciones, se utilizó técnicas histológicas de rutina e histoquímica. Las evidencias demostraron que el hígado contiene tejido pancreático y su arquitectura tisular es trabecular con mayor presencia de capilares sinusoides.

Gambusia holbrooki is the freshwater fish with the greatest distribution in Chile and the world. However, studies dealing with morphology and liver histology of fish are scarce. The liver commonly shows the sublethal effects of environmental pollutants and there should be a histomorphological description of the liver for further comparative studies. The present study aims to describe histomorphological patterns of the liver of Gambusia holbrooki. A total of 97 adult individual specimens were collected from the ecosystems in the valleys of Lluta and Azapa (Region of Arica and Parinacota), to observe patterns morphologically common in both populations. Routine histological and histochemical techniques were used for analysis. The evidence showed that the liver contains pancreatic tissue, and that tissue architecture is trabecular with greater presence of capillary sinusoids.

Review of the family Rivulidae (Cyprinodontiformes, Aplocheiloidei) and a molecular and morphological phylogeny of the annual fish genus Austrolebias Costa 1998

The family Rivulidae is the fourth most diverse clade of Neotropical fishes. Together with some genera of the related African family Nothobranchiidae, many rivulids exhibit a characteristic annual life cycle, with diapausing eggs and delayed embryonic development, which allows them to survive in the challenging seasonal ponds that they inhabit. Rivulidae also includes two species known as the only the self-fertilizing vertebrates and some species with internal fertilization. The first goal of this article is to review the systematics of the family considering phylogenetic relationships and synapomorphies of subfamilial clades, thus unifying information that is dispersed throughout the literature. From this revision, it is clear that phylogenetic relationships within Rivulidae are poorly resolved, especially in one of the large clades that compose it, the subfamily Rivulinae, where conflicting hypotheses of relationships of non-annual and annual genera are evident. The second goal of this work is to present an updated phylogenetic hypothesis (based on mitochondrial, nuclear, and morphological information) for one of the most speciose genus of Rivulidae, Austrolebias. Our results confirm the monophyly of the genus and of some subgeneric clades already diagnosed, but propose new relationships among them and their species composition, particularly in the subgenus Acrolebias.

a familia Rivulidae es el cuarto clado más diverso dentro de los peces Neotropicales. Junto con algunos géneros de la familia Nothobranchiidae, muchos rivulidos presentan un característico ciclo de vida anual, con huevos resistentes a la desecación y embriones con diapausas que les permiten sobrevivir en los ambientes estacionales donde habitan. Los Rivulidae presentan también dos especies consideradas como los únicos vertebrados hermafroditas suficientes y algunas especies con inseminación interna. El primer objetivo de este artículo es actualizar la sistemática de la familia considerando las relaciones filogenéticas y las sinapomorfías de los clados que la componen, reuniendo información que se encuentra dispersa en la literatura. De esta revisión surge que las relaciones filogenéticas dentro de Rivulidae están todavía sin resolver, especialmente en uno de los grandes clados que la componen, la subfamilia Rivulinae, donde relaciones conflictivas entre géneros anuales y no anuales son evidentes. El segundo objetivo de este trabajo es presentar una hipótesis filogenética, basada en datos morfológicos, mitocondriales y nucleares, de uno de los géneros más diversos de la familia, el género Austrolebias. Nuestros resultados confirman la monofilia del género y de algunos clados subgenéricos previamente definidos, y propone nuevas relaciones entre ellos, particularmente de las especies del subgénero Acrolebias(AU)

Colorful invasion in permissive Neotropical ecosystems: establishment of ornamental non-native poeciliids of the genera Poecilia/Xiphophorus (Cyprinodontiformes: Poeciliidae) and management alternatives

Headwater creeks are environments susceptible to invasion by non-native fishes. We evaluated the reproduction of 22 populations of the non-native livebearers guppy Poecilia reticulata, black molly Poecilia sphenops, Yucatan molly Poecilia velifera, green swordtail Xiphophorus hellerii, southern platyfish Xiphophorus maculatus, and variable platyfish Xiphophorus variatus during an annual cycle in five headwater creeks located in the largest South American ornamental aquaculture center, Paraíba do Sul River basin, southeastern Brazil. With few exceptions, females of most species were found reproducing (stages 2, 3, 4) all year round in the creeks and gravid females of all species showed small sizes indicating stunting. Juveniles were frequent in all sites. The fecundity of the six poeciliids was always low in all periods. The sex ratio was biased for females in most species, both bimonthly as for the whole period. Water temperature, water level and rainfall were not significantly correlated with reproduction in any species. Therefore, most populations appeared well established. The pertinence of different management actions, such as devices to prevent fish escape, eradication with rotenone and research about negative effects on native species, is discussed in the light of current aquaculture practices in the region.(AU)

Riachos de cabeceira são ambientes susceptíveis à invasão por peixes não-nativos. Neste trabalho, avaliou-se a reprodução de 22 populações dos poecilídeos não-nativos guppy Poecilia reticulata, molinésia preta Poecilia sphenops, molinésia Poecilia velifera, espadinha Xiphophorus hellerii, plati Xiphophorus maculatus e plati variado Xiphophorus variatus durante diferentes anos em cinco riachos de cabeceira localizados no maior polo de piscicultura ornamental da América do Sul, bacia do rio Paraíba do Sul, sudeste do Brasil. Foram encontradas fêmeas da maioria das espécies em reprodução (estágios 2, 3, 4), durante todos os anos nos riachos e fêmeas grávidas de todas as espécies apresentaram pequeno tamanho indicando nanismo. Juvenis de todas as espécies foram frequentes em todos os locais. A fecundidade das seis espécies sempre foi baixa em todos os períodos. Para os períodos bimestrais e totais, encontrou-se mais fêmeas que machos na maioria das espécies. Temperatura e nível de água dos riachos, bem como precipitação pluviométrica não foram correlacionadas com a reprodução. Todas as populações estão estabelecidas nos locais e ações de gerenciamento como dispositivos para impedir a fuga de peixes, erradicação com rotenona e pesquisa científica sobre os efeitos negativos nas espécies nativas são discutidas em relação às práticas de piscicultura na região.(AU)

A macroscopic classification of the embryonic development of the one-sided livebearer Jenynsia multidentata (Teleostei: Anablepidae)

This study proposes eight stages according to the main discernible changes recorded throughout the embryonic development of Jenynsia multidentata. The development of morphological embryo structures, pigmentation, and changes in tissues connecting mother and embryo were included in the stage characterization. From the fertilized egg (Stage 1), an embryo reaches the intermediary stages when presenting yolk syncytial layer (Stage 2), initial pigmentation of the outer layers of the retina and dorsal region of the head (Stage 3), and the sprouting of the caudal (Stage 4), dorsal and anal fins (Stage 5). During the later stages, the ovarian folds enter the gills, and the body pigmentation becomes more intense (Stage 6), the body becomes elongated (Stage 7), and there is a greater intensity in body pigmentation and increased muscle mass (Stage 8). The dry weight of the batches varied between 0.6 ± 0.3 mg (Stage 3) to 54.6 ± 19.7 mg (Stage 8), but the dry weight of the maternal-embryonic connecting tissues remained almost constant. After controlling the effect of those reproductive tissues, the gain in dry weight of the batches throughout development increased exponentially from Stage 6, reflecting the increase in size and weight of the embryos due to matrotrophy.(AU)

Este estudio propone una clasificación constituida por ocho etapas, establecidas con base en los principales cambios macroscópicos registrados a lo largo del desarrollo embrionario de Jenynsia multidentata. El desarrollo de estructuras embrionarias, los patrones de pigmentación y los cambios en los tejidos de conexión entre la madre y el embrión fueron incluidos en la caracterización de cada etapa. Inicia con el huevo fertilizado (Etapa 1), siguiendo con etapas intermedias del embrión en las cuales es visible la capa sincitial del vitelo (Etapa 2), la pigmentación inicial de las capas externas de la retina y el dorso de la cabeza (Etapa 3), y la aparición de las aletas caudal (Etapa 4), dorsal y anal (Etapa 5). En las etapas posteriores, los pliegues del tejido ovárico se introducen por las branquias y se intensifica la pigmentación corporal (Etapa 6), el cuerpo se extiende (Etapa 7) y hay un marcado aumento en la pigmentación corporal y masa muscular (Etapa 8). El peso seco de los lotes varió entre 0,6 ± 0,3 mg (Etapa 3) y 54,6 ± 19,7 mg (Etapa 8); sin embargo, el peso seco del tejido que conecta a la madre con el embrión se mantuvo prácticamente constante. Después de controlar el efecto del peso seco de estos tejidos, la ganancia de peso seco de los lotes de embriones a lo largo del desarrollo aumentó de forma exponencial a partir de la Etapa 6, evidenciándose en el aumento en tamaño y peso de los embriones debido a la matrotrofia.(AU)

First record of a male of Kryptolebias hermaphroditus Costa, 2011 (Cyprinodontiformes: Cynolebiidae)

During an ichthyological survey in September 2015 at the Ceará-Mirim River estuary, Rio Grande do Norte State, northeastern Brazil, we collected a male of Kryptolebias hermaphroditus , a cynolebiid species that had been previously described as containing exclusively self-fertilizing hermaphrodites. This is the first record of a male in this species, over 140 years after the discovery of the mangrove rivulid species from Brazil. Our discovery reinforces the need for more studies in K. hermaphroditus , as well as the potential of this species as a model for evolutionary studies due to its unique mating system.(AU)

Durante uma amostragem ictiológica em setembro de 2015 no estuário do rio Ceará-Mirim, Estado do Rio Grande do Norte, Nordeste do Brasil, nós coletamos um macho de Kryptolebias hermaphroditus , uma espécie de rivulídeo que foi descrita como contendo apenas hermafroditas auto-fertilizantes. Este é o primeiro registro de um macho dessa espécie, mais de 140 anos depois da descoberta das espécies de rivulídeos de manguezais do Brasil. Nossa descoberta reforça a necessidade de mais estudos em K . hermaphroditus , assim como, o potencial desta espécie como um modelo para estudos evolutivos devido ao seu sistema reprodutivo único.(AU)

Conservation status of an endangered annual fish Hypsolebias antenori (Rivulidae) from Northeastern Brazil / Status de conservação de Hypsolebias antenori (Rivulidae) um peixe anual ameaçado do Nordeste brasileiro

This work presents information regarding the biology and state of conservation of an endangered annual fish Hypsolebias antenori. Fish were captured from small seasonal pools located in Northeastern Brazil. The total body length, body mass, sex ratio, first sexual maturity were investigated. The sampled population showed sexual dimorphism. There was a predominance of females (60%) over males (40%) with a sex ratio of 1: 1.4 and males were bigger and heavier than the females. Amplitude of total length of males ranged from 2.6 to 7.1cm (4.1±1.15) and that of females from 2.2 to 5.4cm (3.6±0.9). Amplitude of body mass of males varied from 0.25 to 7g (1.3g±1.4) and that of females from 0.12 to 2.1g (0.7g±0.5). The total weight-length equation of males was Wt=0.0108Lt3.172 with r = 0.9826 and of females was Wt=0.0122Lt3.0114 with r = 0.9608. Females attained first sexual maturity at 3.2 cm (±0.25) total length and males at 3.3 cm (±0.08) total length. All temporary pools surveyed in Northeastern Brazil were in a high degree of degradation, suffering due to anthropogenic action. Reduced rainfall resulting from global climate change prevents the filling up of these pools, thus preventing the completion of the reproductive cycle of annual fishes. One factor hindering development of conservation strategies is limited literature on biology and conservation status of annual fishes. There is a need for conservation measures to protect annual fish populations, especially creation of protected areas in the Brazilian semiarid region.

Este trabalho apresenta informações sobre a biologia e estado de conservação de Hypsolebias antenori, um peixe anual ameaçado. Os peixes foram capturados em pequenas poças temporárias localizadas no Nordeste do Brasil. O comprimento total, peso total, proporção sexual e a primeira maturação sexual foram investigados. A espécie em estudo apresentou dimorfismo sexual bem evidente. Houve um predomínio de fêmeas (60%) sobre os machos (40%), com uma razão sexual de 1M: 1,4F. Os machos foram significativamente maiores e mais pesados do que as fêmeas. A amplitude do comprimento total dos machos variou de 2,6 a 7,1 centímetros (4,1 ± 1,15) e as fêmeas de 2,2 a 5,4 centímetros (3,6 ± 0,9). A amplitude de peso dos machos variou de 0,25 a 7 g (1,4 ± 1,3 g), enquanto que as fêmeas de 0,12 a 2,1 g (0,5 ± 0,7 g). A equação da relação peso total/comprimento dos machos foi Wt = 0.0108Lt3.172 com r = 0,9826 e para fêmeas foi Wt = 0.0122Lt3.0114 com r = 0,9608. As fêmeas alcançaram a primeira maturação sexual com 3,2 cm ( ± 0,25) de comprimento total e os machos com 3,3 centímetros ( ± 0,08 ) de comprimento total. Todas as poças temporárias amostradas neste trabalho estavam em um alto grau de degradação, principalmente devido à ação antrópica. Observamos que diminuição das chuvas e a desertificação decorrente das mudanças climáticas globais que também são alarmantes e poderão impedir a conclusão do ciclo reprodutivo dos peixes anuais. As informações sobre a biologia e o estado de conservação dos peixes anuais ainda são limitadas, portanto há uma grande necessidade estudos e de medidas de conservação para proteger as populações de peixes anuais, entre elas especialmente a criação de áreas proteção nos ambientes aquáticos efêmeros do semiárido brasileiro.

Spermatozoa characterization in the one-sided livebearing Jenynsia multidentata (Cyprinodontiformes: Anablepidae) / Caracterización de parámetros espermáticos del pez vivíparo Jenynsia multidentata (Cyprinodontiformes: Anablepidae)

Several sperm parameters have been employed as useful tools to evaluate fish fertility. Within teleosts, approximately 3% of fish species are known to be viviparous. The Order Cyprinodontiformes includes several species with internal fertilization, and within this group most of the studies about sperm quality have been mainly focused on the Poeciliidae family. The livebearing fish Jenynsia multidentata (Anablepidae) inhabits an extensive area of the Neotropical region and it has been used as a useful fish laboratory model to evaluate the effects of xenobiotics through different biomarkers. The present work characterized the sperm of this species through a simple protocol of semen collection. Sperm population showed linearity greater than 89% and 70% of fish have a straight line and curvilinear velocity valued between 50 and 100µm/s. Although 85% of individuals showed a proportion of live sperm higher than 60%, the male population had a high degree of heterogeneity in its sperm count. Morphometry analyses showed a total sperm and head lengths of 46.66±2.06µm and 3.46±0.41mm, respectively. A rather long midpiece region (9.12±0.65µm) was registered, which may indicate high energy-producing capabilities of the spermatozoa. This study established basic parameter values which could be useful for evaluating reproductive potential of J. multidentata populations.

Diversos parámetros espermáticos han sido utilizados para evaluar la fertilidad de peces. Dentro de los peces teleósteos, aproximadamente el 3% de las especies son vivíparas. El orden Cyprinodontiformes incluye varias especies con fecundación interna. Dentro de este orden la mayor parte de los estudios sobre la calidad del esperma se han centrado principalmente en la familia Poeciliidae. El pez vivíparo Jenynsia multidentata (Anablepidae) habita una extensa área de la región Neotropical y ha sido utilizado como un exitoso modelo de laboratorio. El objetivo del presente trabajo fue caracterizar los espermatozoides de esta especie a través de un simple protocolo de recolección de esperma. La población de espermatozoides mostró una linealidad superior al 89% y el 70% de los peces tienen una velocidad lineal y curvilineal entre 50 y 100µm/s. Aunque el 85% de los individuos mostró una proporción de espermatozoides vivos de más del 60%, se observó una alta heterogeneidad en el recuento espermático. Los análisis morfométricos mostraron una longitud total de espermatozoides de 46.66±2.06µm y una longitud de la cabeza de 3.46±0.41µm. Los espermatozoides presentan una pieza media larga (9.12±0.65µm) lo que puede indicar una alta capacidad de producción de energía. El presente estudio establece valores básicos de parámetros que pueden ser útiles para evaluar el potencial reproductivo de las poblaciones de J. multidentata.

Diferencias osteológicas entre los subgéneros Profundulus y Tlaloc (Teleostei: Profundulidae) / Osteological differences between the subgenus Profundulus and Tlaloc (Teleostei: Profundulidae)

El género Profundulus es uno de los grupos de peces más antiguos, distribuidos al norte de América Central en México, Guatemala y Honduras. No obstante, son pocos los trabajos que se han realizado para conocer el número de especies que lo conforman y sus relaciones filogenéticas. Históricamente se reconoció que este taxón estaba conformado por dos grupos naturales, actualmente considerados como los subgéneros Profundulus y Tlaloc. Recientes investigaciones genéticas han revelado un alto grado de diferenciación entre ambos taxones y algunas de sus especies, lo cual probablemente este asociado a cambios morfológicos. De esta manera, se realizó la comparación osteológica entre seis especies de los subgéneros Profundulus y Tlaloc (Cyprinodontidae: Profundulidae). Se revisaron 17 huesos ubicados en el cráneo y la cintura pélvica, se encontraron diferencias cualitativas en el mesetmoides, vómer, lacrimal, premaxilar, articular, cuadrado, interopérculo y basipterigio. Los patrones de variación observados permiten diagnosticar ambos subgéneros, corroborando lo encontrado en estudios morfológicos y moleculares. Las evidencias permiten suponer que ambos taxones podrían ser reubicados como géneros, como previamente se había establecido.

The genus Profundulus is one of the oldest fish groups, distributed north of Central America in Mexico, Guatemala and Honduras. However, there are few studies that determine the number of species and their phylogenetic relationships. Historically it has been recognized that this taxon comprises two natural groups, defined as the subgenus Profundulus and Tlaloc. Recent genetic researches have revealed a high degree of differentiation between the two taxa and some species, probably associated with the morphological changes. In this way, we made the osteological comparison between six species of the subgenus Profundulus and Tlaloc (Cyprinodontidae: Profundulidae). We reviewed 17 bones located in the skull and pelvic girdle; qualitative differences were found in eight bones: the mesethmoid, vomer, lachrymal, premaxilla, articular, quadrate, interoperculum, and basipterygium. The variation patterns permit to diagnose both subgenus, corroborating the previous morphological and molecular studies. The evidence suggests that both taxa could be relocated as genus, such as previously was established.

Reproductive strategies of two Neotropical killifish, Austrolebias vandenbergi and Neofundulus ornatipinnis (Cyprinodontiformes: Rivulidae) in the Bolivian Gran Chaco / Estrategias reproductivas de dos especies de rivulidos Neotropicales Austrolebias vandenbergi y Neofundulus ornatipinnis (Cyprinodontiformes: Rivulidae) en el Gran Chaco Boliviano

The dry Chaco, a semiarid thorn forest, is experiencing some of the highest deforestation rates globally, coupled with the fact that small-bodied fish are at the highest risk of extinction, the killifish inhabiting this region may be some of the most threatened taxa. Yet, aspects of ecology and life history for Neotropical killifishes in the Bolivian Gran Chaco region are completely lacking, and basic life-history data is of critical importance for the design and implementation of conservation measures. Collections were conducted during the early (January 2011) and late (March-April 2011) rainy season using an area-based sampler and dip net surveys. Fish standard length and body depth were measured as well as the number of oocytes per size class, mean oocyte diameter per size class, and total fecundity for the females of each species. A total of 490 specimens of rivulids were captured; Austrolebias vandenbergi: 85 females, 105 males and 39 juveniles, and N. ornatipinnis: 62 females, 113 males, 86 juveniles. Sexual size dimorphism, absolute fecundity, oocyte developmental stages, oocyte diameter, and population sex ratios were determined for each species. Both species exhibited sexual size dimorphism. Male A. vandenbergi exhibited longer standard length (mean±SD; males: 27.07±3.89mm, females: 23.6±2.02mm) and body depth (males: 8.9±1.7mm, females: 7.2±1.1mm) as compared to females. Male N. ornatipinnis had a similar pattern for both standard length (males: 26.0±7.1mm, females: 19.1±5.83mm) and body depth (males: 5.6±1.9mm, females: 4.7±1.0mm). Austrolebias vandenbergi had fewer and smaller oocytes per female (47±31.6) than N. ornatipinnis (206±131.2). There was a positive relationship between fecundity and female body size in both species. The presence of multiple developmental stages of oocytes (immature, maturing, and mature) suggest that both species of rivulids exhibit fractional spawning, a reproductive strategy that enhances reproductive success in these extreme habitats. Neofundulus ornatipinnis exhibited a higher mean oocyte diameter for all three developmental stages (immature, maturing, and mature) as compared to A. vandenbergi. Austrolebias vandenbergi exhibited an equal adult sex ratio (males:females, 1:1), but there was a slight female biased ratio for N. ornatipinnis (males:females, 1:1.8). These results provide fundamental and valuable information for ensuring rivulid conservation in tropical regions, and also improve the knowledge on the biology and ecology of these poorly known species. To our knowledge, this study represents the first contribution on the reproductive biology of two Neotropical annual rivulid fishes (Austrolebias vandenbergi and Neofundulus ornatipinnis) inhabiting semi-permanent and ephemeral ponds in the Gran Chaco of Southeastern Bolivia.

Información sobre la ecología e historia de vida de varias especies de rivulidos no ha sido estudiada, por lo tanto se analiza la biología reproductiva de dos especies neotropicales (Austrolebias vandenbergi y Neofundulus ornatipinnis) que habitan pozos semipermanentes y temporales en el Gran Chaco Boliviano. Las recolectas se realizaron al inicio y al final de la estación lluviosa. Dimorfismo sexual, fecundidad absoluta, diámetro de los ovocitos y proporción sexual fue determinada para cada especie de rivulido. Machos en las dos especies presentaron mayor tamaño de longitud estándar y altura del cuerpo cuando fue comparado con las hembras. Austrolebias vandenbergi tuvo menor fecundidad por hembra y huevos más pequeños que N. ornatipinnis, pero hembras en ambas especies presentaron una relación estrecha y positiva entre fecundidad y tamaño cuerpo. La presencia de varios estadios gonadales sugiere un desove fraccionado, lo cual es una estrategia reproductiva que promueve la viabilidad y sobrevivencia de estos peces en hábitats de extremas condiciones. La proporción sexual no varió entre machos y hembras de A. vandenbergi (1:1), pero en N. ornatipinnis la proporción sexual fue dominada por las hembras (1:1.8). Este estudio representa uno de los primeros que investiga aspectos de la biología reproductiva de A. vandenbergi y N. ornatipinnis, lo cual es importante para la conservación de rivulidos en regiones tropicales.

Proteínas totales y factor de bioconcentración por exposición a metales en la Gambusia punctata (Poeciliidae) / Total proteins and bioconcentration factor by metal exposure in Gambusia punctata (Poeciliidae)

El objetivo del presente trabajo fue evaluar niveles de proteínas totales y el factor de bioconcentración por exposición a metales en la Gambusia punctata. La especie fue muestreada en el ecosistema Filé y luego trasladada hacia condiciones de laboratorio, donde fueron diseñados 3 tratamientos a 2 réplicas con 25 ejemplares. Se determinó la concentración letal media (CL-50) como parámetro de toxicidad durante 48 horas de bioensayo. Los metales analizados fueron plomo y cadmio, cuantificados por espectroscopia de plasma inductivamente acoplados con vista axial. Transcurrido el experimento, la CL-50 correspondió a 0,1, ensayándose las concentraciones 0,06 y 5,78 mg/L, además del control negativo. Posteriormente se cuantificó el nivel de proteínas totales y los metales en agua, tejido y su relación mediante el factor de bioconcentración. El menor valor de proteínas fue ante la exposición al cadmio, con 43,9 por ciento de inhibición (p< 0,05) en comparación con el control; en el caso del plomo se determinó 2,5 por ciento de estimulación. Las mayores concentraciones en agua y tejido correspondieron a este último, no así para el factor de bioconcentración. Se concluyó que los resultados mostraron sensibilidad en la respuesta del contenido de proteínas totales y alta capacidad bioacumulativa para ambos metales.

The aim of this study was to evaluate levels of total proteins and the bioconcentration factor by metal exposure in Gambusia punctata. The species was sampled in the ecosystem Filé and then transferred to the laboratory, where 3 treatments in 2 replications with 25 copies were designed. Mean lethal concentration (CL-50) was determined as a toxicity parameter for 48 hours of bioassay. The analyzed metals were lead and cadmium, quantified by plasma spectroscopy inductively coupled with axial view. After the experiment, the CL-50 corresponded to 0.1 and concentrations of 0.06 and 5.78 mg/L and the negative control were tested. Then the level of total proteins and metals in water, tissue and its relationship by means of the bioconcentration factor were quantified. The lower value of proteins was by exposure to cadmium with 43.9 percent of inhibition (p <0.05) compared with the control; for lead 2.5 percent of stimulation was determined. The highest concentrations in water and tissue corresponded to the latter, but not for the bioconcentration factor. It was concluded that the results showed sensitivity in the response of total protein content and a high bioaccumulative capacity for both metals.

Bothriocephalus acheilognathi (Cestoda) in the endangered fish Profundulus hildebrandi (Cyprinodontiformes), Mexico

The Asian fish tapeworm, Bothriocephalus acheilognathi, has been considered one of the most dangerous parasites for cultured carp and a risk for native freshwater fish populations worldwide. This cestode is highly pathogenic for fishes especially fry. In this paper we record B. acheilognathi parasitizing the endangered and endemic freshwater fish Profundulus hildebrandi from the endorheic basin of San Cristóbal de las Casas, Chiapas, Mexico. B. acheilognathi was recorded from 10 of the 11 sampled localities, with high values of prevalence (>60%) and mean abundance (>4.50). The infection was persistent all through the year; gravid cestodes were recorded in all samples. It is assumed that B. acheilognathi entered to this area through the introduction of common carp Cyprinus carpio, for aquacultural purposes. The data presented in this paper document the successful introduction, colonization and establishment of this alien species into the endangered P. hildebrandi. Rev. Biol. Trop. 59 (3): 1099-1104. Epub 2011 September 01.

El céstodo Asiático, Bothriocephalus acheilognathi, es considerado como uno de los helmintos más peligrosos para peces de cultivo, y un riesgo potencial para las poblaciones silvestres de peces en todo el mundo. La patología que causa es grave, principalmente en larvas y juveniles de peces. En este trabajo registramos la presencia de B. acheilognathi en el pez endémico de Chiapas y amenazado de extinción, Profundulus hildebrandi, en la cuenca endorreica de San Cristóbal de Las Casas, Chiapas, México. El céstodo B. acheilognathi fue registrado en 10 de las 11 localidades muestreadas, con valores altos de prevalencia (>60%) e intensidad promedio (>4.50). Registramos esta infección durante todo el año, con presencia de céstodos grávidos en todos los meses muestreados. Asumimos que B. acheilognathi ingresó a esta área geográfica con la introducción de la carpa común, Cyprinus carpio, para acuicultura. Los datos que presentamos en este trabajo documentan la introducción exitosa, la colonización y el establecimiento de esta especie exótica de parásito sobre P. hildebrandi, especie dulceacuícola, endémica y amenazada de extinción.

Diet of four annual killifishes: an intra and interspecific comparison

We examined the diet of 4 annual fishes, Austrolebias viarius, Austrolebias cheradophilus, Austrolebias luteoflammulatus and Cynopoecilus melanotaenia inhabiting temporal ponds of southeastern Uruguay, by analysis of stomach contents. Fishes were captured from fifty ephemeral ponds of Castillos Lagoon basin, in the region of the Humedales del Este. We identified 13099 individual prey items extracted from 669 stomachs of the four captured species. In the studied system, annual killifishes represents the most abundant and conspicuous top predators. Killifishes are generalist key predators at the ephemeral ponds of the studied system, consuming mostly aquatic items. Zooplancton represented the bulk of the diet in the four analyzed species, followed by eggs, algae and diatoms. Insects are the next group in prey number, as follows: Diptera larvae (especially Chironomidae and Cullicidae), Ephemeroptera (especially Betidae), and coleopteran larvae (especially Dytiscidae). Acari are also important prey in number. The four fish species differ in diet composition and in diet richness. A general pattern of differences in diet richness among killifish species and demographic groups could be related to variations in body sizes. As top predators annual killifishes are an important component of the temporal pond ecosystems. Understanding the natural history of this species and their communities is necessary in order to conserve them.(AU)

Nós examinamos a dieta de 4 peixes anuais, Austrolebias viarius, Austrolebias cheradophilus, Austrolebias luteoflammulatus e Cynopoecilus melanotaenia, que habitam poças temporárias do sudeste do Uruguai, através da análise de conteúdo estomacal. Os peixes foram capturados em cinco poças temporárias da bacia da lagoa Castillos, na região de Humedales del Este. Nós identificamos 13099 itens de presas estraídos de 669 estômagos das quatro espécies. No sistema estudado, peixes anuais representam os predadores de topo mais abundantes e conspícuos. Os rivulídeos são predadores generalistas nas poças temporaries estudadas, consumindo principalmente itens aquáticos. Zooplâncton representou o item principal da dieta para as quatro espécies, seguido de ovos, algas e diatomáceas. Insetos compoem o próximo grupo em número de presas, como segue: larvas de Diptera (especialmente Chironomidae e Cullicidae), Ephemeroptera (especialmente Betidae), e larvas de Coleoptera (especialmente Dytiscidae). Ácaros foram também presas importantes em número. As quatro espécies de peixes diferem na composição e riqueza das dietas. O padrão geral de diferenciação da dieta entre espécies e grupos demográficos de rivulídeos pode ser relacionado à variação do tamanho corporal. Como predadores de topo, os rivulídeos anuais são um componente importante dos ecossistemas de poças temporárias. A compreensão da história natural destas espécies e de suas comunidades é necessária a sua conservação.(AU)

Protozoan parasites of Xiphophorus spp. (Poeciliidae) and their relation with water characteristics / Parasitos protozoários de Xiphophorus sp. (Poeciliidae) e a relação deles com as características da água

This work investigated the relationship between water characteristics and infestation of protozoan parasites, Icthyophthirius multifiliis and Trichodina sp., in swordtails (Xiphophorus helleri) and platy (Xiphophorus maculates) collected in an ornamental fish farm in São Paulo, Brazil. Fish were monthly collected from ponds and tanks for one year. The prevalence rates in fish from tanks and ponds were, respectively, 34.2 percent and 22.5 percent for I. multifiliis, and 13 percent and 54.2 percent for Trichodina sp. Increased electric conductivity and pH provoked reduction of I. multifiliis infestation. Low oxygen concentration increased Trichodina sp. infestation. The use of salt to increase the electric conductivity of water was a method to control I. multifiliis. Low dissolved oxygen and the addition of organic fertilizer favored the reproduction of Trichodina sp.

Investigou-se a relação entre as características da água e a infestação de protozoários parasitos, Icthyophthirius multifiliis e Trichodina sp., em peixe espada, Xiphophorus helleri e em plati, Xiphophorus maculatus, coletados em uma piscicultura de peixes ornamentais no Estado de São Paulo, Brasil. Os peixes foram coletados mensalmente, durante um ano, dos viveiros e das caixas de estocagem. A prevalência da infestação nos peixes das caixas e dos viveiros foram, respectivamente, 34,2 por cento e 22,5 por cento para I. multifiliis e 13 por cento e 54 por cento para Trichodina sp. A elevada condutividade elétrica e o pH da água reduziram a infestação por I. multifiliis. A baixa concentração de oxigênio resultou em aumento na infestação por Trichodina sp. O uso do sal, para aumentar a condutividade elétrica da água, consistiu em um método de controle de I. multifiliis. A redução do oxigênio dissolvido e a adição de fertilizante orgânico favoreceram a reprodução de Trichodina sp.

Distribution of guppies Poecilia reticulata (Peters, 1860) and Phalloceros caudimaculatus (Hensel, 1868) along a polluted stretch of the Paraíba do Sul River, Brazil / Distribuição dos guppies Poecilia reticulata (Peters, 1860) e Phalloceros caudimaculatus (Hensel, 1868) ao longo de um trecho poluído do rio Paraíba do Sul, Brasil

Cyprinodontiformes fishes (guppies) are widely distributed in Neotropical regions and use deteriorated microhabitats in rivers where few species can occur. This study was carried out in a stretch of the Paraíba do Sul River in bracketing a large urban-industrial complex. The aim was to assess eventual effects that the industrial complex could have on distribution of two closely related fish species of guppies, Phalloceros caudimaculatus and Poecilia reticulata. The area was divided into three zones: Z1, 40 km upriver of the major urban-industrial complex of Volta Redonda; Z2, just down river of the complex; and Z3, 30 km down river of the complex. Six sites (two in each zone) were sampled monthly between November 1998 and October 1999, using a standardized fishing effort with cast net throws, trays lifts and seine hauls, covering different microhabitats, that is, riffles, pools and the proximity of the river's margins. Poecilia reticulata was widely distributed, peaking at Z2, the most polluted area, while P. caudimaculatus showed the highest abundance at Z3, being almost absent in Z1. Both species occurred in high numbers throughout the year but they were scarce between April and June. Females outnumbered males for both species in most size classes and at all sites. Juveniles were more abundant than adults, with non-pregnant females outnumbering pregnant ones. Condition factor was always higher in males than females but only males P. reticulata showed significant difference among the three zones, with the highest values at Z2. The higher number of females confirms the expectation that these species can use very polluted areas and that availability of food provided by organic loads allowed their distribution all over the area. Although these two species have shown indication of spatial separation in the study area, their similar seasonal patterns of occurrence suggest that they respond in a similar way to changes in environmental conditions.

Peixes Cyprinodontiformes (guppies) são largamente distribuídos na região Neotropical e usam microhábitats deteriorados em rios onde poucas espécies podem ocorrer. Este estudo foi realizado em um trecho do rio Paraíba do Sul compreendendo um grande complexo urbano-industrial. O objetivo foi avaliar eventuais efeitos que o complexo industrial poderia ter na distribuição de duas espécies de guppies proximamente relacionadas, Phalloceros caudimaculatus e Poecilia reticulata. A área foi dividida em três zonas: Z1, 40 km rio acima do complexo urbano-industrial de Volta Redonda; Z2, imediatamente abaixo do complexo industrial; e Z3, 30 km abaixo do complexo. Seis locais (dois em cada zona) foram amostrados mensalmente entre novembro de 1998 e outubro de 1999, usando um esforço de pesca estandardizado com tarrafas, peneiras e arrastos, cobrindo diferentes microhábitats, isto é, corredeiras, remansos e a proximidade da margem dos rios. Poecilia reticulata foi largamente distribuído, apresentando pico na Z2, área mais poluída, enquanto P. caudimaculatus apresentou a maior abundância na Z3, sendo quase ausente na Z1. Ambas as espécies ocorreram em elevados números ao longo do ano, mas foram escassas entre abril e junho. Fêmeas foram mais numerosas do que machos para ambas as espécies na maioria das classes de tamanho e em todos os locais. Jovens foram mais abundantes que adultos, com fêmeas não grávidas predominando sobre fêmeas grávidas. Fator de condição foi sempre maior nos machos do que nas fêmeas, mas somente machos de P. reticulata apresentaram diferenças significantes entre as três zonas, com os mais elevados valores na Z2. Maior número de fêmeas confirma as expectativas de que estas espécies podem usar áreas bem poluídas e que a disponibilidade de alimento provida pela carga orgânica permite sua distribuição ao longo de toda a área. Embora estas duas espécies tenham apresentado indicações de separação especial, seus similares padrões de ...

A new species of poeciliid fish, Poeciliopsis santaelena, from Peninsula Santa Elena, Area de Conservación Guanacaste, Costa Rica

An undescribed freshwater fish was recently discovered during a biological inventory of Area de Conservación Guanacaste, northwestern Costa Rica. This new species of Poeciliopsis is closely related to a group of widespread species of small spotted fishes designated as the Poeciliopsis gracilis complex in this study. The complex extends on both versants from southern Mexico to Nicaragua, and with this new finding, extends into Costa Rica. The new species is distinguished from its Central American relatives by its lack of lateral and ventral markings, higher pectoral and caudal-fin counts and more posterior placement of the dorsal fin. Poeciliopsis santaelena is endemic to the Río Potrero Grande, a river whose flow is reduced to just a few pools during the long dry season and flows fully only during very rainy weather. It is just another in a growing list of threatened or endangered species found in this unique peninsular environment. Rev. Biol. Trop. 56 (2): 829-838. Epub 2008 June 30.

Recientemente se descubrió una especie no descrita de pez dulceacuícola durante un inventario biológico en Area de Conservación Guanacaste (ACG) en el noroeste de Costa Rica. Esta especie nueva del género Poeciliopsis tiene un parentesco cercano con un grupo de especies con puntos en los costados ampliamente distribuidas que se designan en este informe como complejo de Poeciliopsis gracilis. El complejo se extiende en ambas vertientes desde el sur de México hasta Nicaragua. La especie nueva se distingue de sus parientes centroamericanos por su falta de manchas negras laterales y ventrales, mayor número de radios pectorales y caudales, y posición más posterior de la aleta dorsal. Poeciliopsis santaelena, especie endémica de un sólo riachuelo intermitente, es una especie más in la lista de especies en peligro que se encuentra en este peculiar ambiente peninsular.

Camallanus maculatus n. sp. (Nematoda: Camallanidae) in an ornamental fish Xiphophorus maculatus (Osteichthyes: Poeciliidae) cultivated in São Paulo State, Brazil

The present study describes Camallanus maculatus n. sp. (Nematoda: Camallanidae) from Xiphophorus maculatus (Osteichthyes: Poecilidae) collected in an ornamental fish farm in São Paulo State, Brazil. Thirty-three out of 40 examined fish were parasitized (82 percent prevalence) with mean intensity of 2.8 (1-20). Male specimens were 3,500µm total length and females 7,100µm total length, provided with orange-brown buccal capsule and two developed tridents. Males showed two unequal spicules, gubernaculum absent and females with vulva situated in the middle of the body. The main characteristics were the sleekly longitudinal ridges in the buccal capsule in both sexes, enlargement at the anterior end of the smaller spicule, the number of genital papillae, longer muscular and glandular portion of esophagus and round tail in female

Descreve-se Camallanus maculatus n. sp. (Nematoda: Camallanidae) em Xiphophorus maculatus (Osteichthyes: Poecilidae) capturado em uma piscicultura ornamental no estado de São Paulo. De 40 peixes examinados, 33 estavam parasitados (prevalência de 82 por cento) cuja intensidade média foi de 2,8 (1-20). Os machos apresentaram 3.500µm e as fêmeas com 7,100µm de comprimento total, providos de uma cápsula bucal laranja-castanho e dois tridentes. Observaram-se machos com espículos desiguais, gubernáculo ausente e fêmeas com vulva situada na metade do corpo. As principais características foram as estrias longitudinais lisas em cada valva da cápsula bucal em ambos os sexos, o espículo menor com alargamento na extremidade anterior, o número de papilas genitais, as porções muscular e glandular do esôfago longas e a cauda longa e arredondada na fêmea

Alimentación de los peces dulceacuícolas tropicales Heterandria bimaculata y Poecilia sphenops (Cyprinidontiformes: Poeciliidae)

Diet of the tropical freshwater fish Heterandria bimaculata (Haeckel) and Poecilia sphenops Valenciennes (Cyprinidontiformes: Poeciliidae). We analyzed the diet and feeding habits of the fishes Heterandria bimaculata and Poecilia sphenops. Specimens were captured monthly in "Los Carros" damp, Morelos, Mexico (18°37´ N, 98°43´ W). We quantified gut content by the numerical method and by the frequency of occurrence method; and used the MacArthur and Levin´s indices for niche overlap. The diet of H. bimaculata was composed by 16 prey categories, mainly dipterans (Culicidae predominated), independently of sex, size and season. The index of niche overlap was high, from 0.74 to 0.99. The diet of P. sphenops consisted of 11 items, detritus being the most consumed, also independently of sex, size and season. The niche overlap index was high (0.99), indicating overlapping for all analyses. There was little diet overlap (0.26) between the two species. Rev. Biol. Trop. 55 (2): 603-615. Epub 2007 June, 29.

Se analizó la dieta y los hábitos alimentarios de Heterandria bimaculata y Poecilia sphenops. Se tomaron muestras mensuales en la presa "Los Carros", Morelos, México (10°37´ N, 98°43´ W). El contenido intestinal fue analizado de acuerdo con los métodos numérico (No) y el de frecuencia de presencia (FO). Se utilizó el índice de traslape de MacArthur y Levin. H. bimaculata presentó la ingestión de 16 componentes alimenticios. Los odonatos y los himenópteros fueron los más consumidos en le estación de lluvias, mientras que en el estiaje fueron los himenópteros y coleópteros. La talla II fue la que registró la mayor diversidad, siendo los himenópteros los más consumidos en las tres tallas. El índice de traslape en cada uno de los análisis fue de 0.74 a 0.99. P. sphenops consumió 11 tipos de alimento; el detrito registró los porcentajes más altos independientemente de sexo, tamaño y época (índice de traslape = 0.99). Ambas especies comparten seis alimentos, pero en bajas proporciones (índice de traslape = 0.26).