Determining the factors that give rise to reproductive isolation is critical for understanding how species form. Observing reproductive isolation between closely related populations is especially interesting because it can show the factors initially involved in species formation. We studied two phenotypically different populations of Side-Blotched Lizards (Uta stansburiana), which diverged less than 22,500 years ago according to geologic evidence. The lava flow population has dark dorsal coloration for crypsis and is dimorphic for throat coloration used for signaling male mating type. The off-lava population has light dorsal coloration and is trimorphic for throat coloration. We tested whether there was reproductive isolation between these two populations in order to understand the factors that maintain the phenotypic differences between these populations. Our genetic crosses revealed evidence of reproductive incompatibilities because females from the dimorphic lava population produced fewer fertilized eggs and more unfertilized eggs when mated outside their population. In addition, male morphs varied in their reproductive compatibility because females from both populations produced fewer fertilized eggs and fewer clutches with orange-throated males from outside their population. The reproductive incompatibilities observed between the populations suggest that cryptic female choice of sperm may act as a post-mating, prezygotic barrier that contributes to the rapid formation of new species.

We report a new fossil amiid from Eocene rocks of West Africa representing the first record of this clade from Senegal. The new specimen has a maxilla that is very similar in size to that of Amia calva. It is distinctly smaller than reported remains of another West African Eocene taxon, †Maliamia gigas. We tentatively refer the Senegal specimen to Vidalamiini because it has the large postmaxillary process diagnostic of this clade; however, it also exhibits anatomical features not previously described in extinct amiids. We recovered the specimen in rocks of the Lam-Lam Formation in Central-Western Senegal that we interpret to have been a shallow marine depositional environment. The occurrence of an Eocene marine amiid contradicts existing hypotheses that marine amiids were generally absent after the Cretaceous–Paleogene boundary having been replaced by freshwater taxa. Research completed since the initial discovery of †Maliamia gigas indicates that this Eocene taxon was also found in shallow marine rocks.

Nous avons découvert un poisson fossile dans les sédiments éocènes de l'Afrique de l'Ouest, le premier représentant du clade des Amiidae au Sénégal. Le nouveau fossile a presque la même taille que l'espèce actuelle, Amia calva. Le fossile sénégalais a une longue processus postmaxillaire diagnostique de Vidalamiini. Le fossile montre aussi plusieurs charactéristiques anatomiques qui n'ont jamais été décrites chez les Amiidés fossiles. Nous avons trouvé le fossile dans les sédiments de la Formation du Lam-Lam au Centre-Ouest du Sénégal, et nous les interprétons comme des sédiments marins. La découverte d'un amiidé dans les gisements éocènes marins contredit l'hypothèse selon laquelle on ne trouve plus d'amiidés marins au-dessus de la limite Crétacé–Paléogène et qu'ils ont été remplacés par les amiidés d'eau douce. Les travaux stratigraphiques menés depuis la découverte de †Maliamia gigas ont montré que cette espèce était aussi présente dans les gisements marins.

Hollandichthys and Rachoviscus are endemic to the Atlantic coastal drainages of Brazil and have been historically hypothesized as related to different genera and even subfamilies of the Characidae. We describe the testis morphology, spermiogenesis, and sperm ultrastructure of species of both genera under light, transmission, and scanning electron microscopy, and provide unique characters that support a close relationship among Hollandichthys and Rachoviscus. The testes have a similar organization with a tripartite structure, showing a spermatogenic-cranial region, a differentiating-intermediate region, and a storage-caudal region that is continuous with the sperm duct. During spermiogenesis, the final spermatic differentiation occurs in the luminal compartment of the differentiating-intermediate region of the testis. This is herein termed as “partially cystic,” being distinct from that of any other characids previously described. At the beginning of spermiogenesis, the centriolar complex lies in a medial position in relation to the nucleus, the nucleus moves and slightly elongates toward the flagellar axis forming an eccentric nuclear fossa, and then the nucleus turns backward and elongates forward. The species of both Hollandichthys and Rachoviscus share the presence of long, spiraling mitochondria in the midpiece that seem to be unique among characids. Sperm competitiveness seems to be a determinant factor in accelerating the rate of phenotypic changes in nucleus length and sperm shape among inseminating characids. This is exemplified by the differences found in sperm nucleus shape and length between the two sister species of Rachoviscus, as well as between these species and their sister lineage (Hollandichthys). The formation of sperm packages was observed in Rachoviscus graciliceps.

Hollandichthys e Rachoviscus são gêneros endêmicos das drenagens costeiras Atlânticas do Brasil e tem sido historicamente considerados como relacionados a gêneros e até mesmo subfamílias distintas de Characidae. A morfologia dos testículos, a espermiogênese e a ultraestrutura dos espermatozóides das espécies dos dois gêneros são descritas sob microscopia ótica e microscopia eletrônica de transmissão e varredura, fornecendo caracteres únicos que suportam uma relação próxima de parentesco. Os testículos apresentam uma organização semelhante em uma estrutura tripartite, com uma região espermatogênica-craniana, uma região de diferenciação intermediária e uma região caudal de armazenamento, que é contínua com o ducto espermático. Durante a espermiogênese, a diferenciação final do espermatozóide ocorre no compartimento luminal da região intermediária dos testículos, sendo aqui denominada de espermiogênese “parcialmente cística,” distinta de qualquer outra descrita anteriormente em Characidae. No início da espermiogênese, o complexo centriolar encontra-se em uma posição medial em relação ao núcleo, o núcleo se move e se alonga um pouco em direção ao eixo flagelar formando uma fossa nuclear excêntrica, e, em seguida, o núcleo retorna e se alonga para a frente. As espécies de Hollandichthys e Rachoviscus compartilham a presença de mitocôndrias espirais na peça intermediária, que parece ser única em Characidae. A competição do esperma parece ser um fator determinante na aceleração do ritmo das alterações fenotípicas de comprimento do núcleo e forma do espermatozóide entre os caracideos inseminadores, exemplificado pelas diferenças encontradas entre as duas es

A new species of catfish of the subfamily Doumeinae, of the African family Amphiliidae, was discovered from the Kasai River system in northeastern Angola and given the name Congoglanis howesi. The new species exhibits a combination of proportional body measurements that readily distinguishes it from all congeners. This brings to four the number of species of Congoglanis, all of which are endemic to the Congo River basin.

Trichomycterus minus, new species, is described from an Andean stream in Provincia de Catamarca, Argentina. The new species is distinguished from congeners by the number of supraorbital pores, the form of the supraorbital canal within the frontal, the length of the lateral line canal, the shape of the supraorbital tendon bone, the size of the premaxilla, the form of the barbels, an absence of a thick layer of rugose fatty tissue on the head and body, the number and degree of exposure of odontodes on the interopercle, the limited compression of the caudal peduncle, details of pigmentation, the number of premaxillary tooth rows, and the head form from a dorsal view. Trichomycterus corduvensis is recorded from thermal waters, the second locality known to be inhabited by members of the genus.

Trichomycterus minus, nueva especie, es descripta para un arroyo andino en la Provincia de Catamarca, Argentina. La nueva especie se diferencia de los congéneres por el número de pores supraorbitales, la forma del canal supraorbital dentro del frontal, la longitud del canal de la línea lateral, la forma del hueso supraorbital, el tamaño del premaxilar, la forma de las barbillas, la ausencia de una gruesa capa de tejido graso sobre la cabeza y cuerpo, el número y grado de exposición de odontoides en el interopérculo, la ausencia de compresión del pedúnculo caudal, los detalles de pigmentación, el número de hileras de dientes premaxilares y la forma de la cabeza en vista dorsal. Trichomycterus corduvensis es registrado para aguas termales, la segunda localidad conocida para los miembros del géneros.

Nannoplecostomus eleonorae, a new genus and species of a miniature suckermouth armored catfish, is described based on specimens collected from the karst region of São Domingos, upper Rio Tocantins basin, Goiás State, central Brazil. The new genus and species can be diagnosed among loricariids by presenting a unique reductive pattern of lateral dermal plates, with most of the body covered by only three series of plates (viz., dorsal, mid-ventral, and ventral). Based on the available published phylogenetic studies for the family, we provisionally consider Nannoplecostomus eleonorae as being an incertae sedis taxon within Loricariidae. Achieving a maximum standard length of 22.2 mm SL, Nannoplecostomus eleonorae is the smallest known loricariid catfish, and a list of the remaining smallest loricariids is provided.

É descrito um novo gênero e espécie de cascudo miniaturizado, Nannoplecostomus eleonorae, baseado em espécimes coletados na região de carste de São Domingos, bacia do alto rio Tocantins, estado de Goiás, Brasil central. O novo gênero e espécie pode ser diagnosticado dos demais loricarídeos por apresentar um padrão de redução das placas dérmicas laterais único, em que a maior parte do corpo é recoberta por apenas três séries de placas (viz., séries dorsal, médio-ventral e ventral). Baseado nos estudos filogenéticos publicados para a família, consideramos Nannoplecostomus eleonorae como sendo um táxon incertae sedis dentro de Loricariidae. Atingindo um comprimento padrão máximo de 22,2 mm CP, Nannoplecostomus eleonorae é o menor loricarídeo conhecido, e uma lista dos demais menores loricarídeos é fornecida.

We describe a new frog species of the genus Guibemantis in the subgenus Pandanusicola from southeastern Madagascar and provide a redescription of a morphologically similar species, G. pulcher, based on its type series and on newly collected material. The new species, Guibemantis tasifotsy, differs from most Pandanusicola by probably not breeding in leaf axils of Pandanus plants but instead was collected calling from the vegetation above large, open lowland swamps. The green dorsal color of the new species is reminiscent of Guibemantis pulcher but can be distinguished from this Pandanus-breeding species by the presence of prominent white blotches along the flanks and by the structure of femoral glands in males. It shares these character states with G. liber from which the new species differs in details of coloration and advertisement call. Newly determined DNA sequences of the cytochrome b gene confirm that G. tasifotsy is genetically highly divergent from all other species of Guibemantis.

A new species of Potamorrhaphis is described from the Amazon basin in Brazil and Peru. Potamorrhaphis labiatus, new species, is distinguished from P. guianensis and P. eigenmanni by having the posterior third of the labial membrane highly expanded laterally, reaching to or passing the level of the ventral margin of the maxilla when folded ventrally, and from P. petersi by having fewer dorsal- and anal-fin rays and a deeper caudal peduncle. A key for the species of Potamorrhaphis is provided.

Uma nova espécie de Potamorrhaphis é descrita da bacia do rio Amazonas no Brasil e no Peru. Potamorrhaphis labiatus n. sp. se distingue de P. guianensis e P. eigenmanni por ter o terço posterior da membrana labial fortemente expandida lateralmente, alcançando ou ultrapassando o nível da margem ventral da maxila quando virada para baixo, e de P. petersi pelo menor número de raios nas nadadeiras dorsal e anal e pelo pedúnculo caudal mais alto. Uma chave de identificação para as espécies de Potamorrhaphis é fornecida.

A new species of Scoloplax is described with a remarkable new tooth morphology, possessing dentary teeth with four cusps and premaxillary teeth with two to four cusps, features unique among all Loricarioidea and rare among Siluriformes. Scoloplax baileyi, new species, is further distinguished by eight diagnostic features. The new species is found in the small tributaries of Rio Unini, an important tributary to the Rio Negro, and in the Anavilhanas Archipelago, lower Rio Negro, Amazonas State, Brazil. Based on a review of scoloplacids, a new record of S. baskini is given to include the Rio Negro, increasing the number of species of Scoloplax from that basin to four.

The acquisition of signals used in intrasexual communication is not well studied. To better understand the possible contribution of early experience to the acquisition of intrasexual responses, we reared Neotropical Túngara frogs, Physalaemus pustulosus, in four acoustic environments: 1) conspecific chorus, 2) heterospecific chorus, 3) acoustic isolation, and 4) noise. For the heterospecific chorus, we chose the calls of a congener, P. enesefae, with which P. pustulosus is sympatric in parts of its distribution. We measured the evoked vocal responses (EVR) of these frogs in response to calls of the conspecifics, to calls of the congener, and to calls representing an intermediate between the two species. Male P. pustulosus reared hearing the calls of P. enesefae produced more calls overall and more complex calls in response to the call of P. enesefae. This is consistent with the hypothesis that the EVR of male anurans can be influenced by early experience and is the product of an interaction between genes and the environment.

Many species of frogs that breed in bromeliads exhibit parental care as females deposit unfertilized eggs to feed the tadpoles. Treefrogs of the genus Scinax are not known to exhibit this behavior, even though they have exotrophic tadpoles. The purpose of this study was to describe qualitatively and quantitatively the diets of tadpoles of hylids S. littoreus and S. perpusillus developing in the phytothelm of Alcantarea glaziouana (Bromeliaceae). We evaluate if there are seasonal and spatial differences (between tadpoles living in the central tank and the lateral tanks) in the diet, and to test for food selectivity of the species. The most abundant items in the diet of tadpoles of both species were, respectively, algae, fungi, and protozoa. Detritus and plant debris were present in the diet of more than 90% of the tadpoles of the two species. The trophic niche breadth for S. littoreus was 1.26, whereas that for S. perpusillus was 1.54. The tadpole diets were seasonally conservative for both tadpole species and spatially similar only for S. perpusillus. Tadpoles of Scinax littoreus showed differences in diet, depending on the microhabitat in which they developed in the bromeliad, and showed electivity favorable for fungi but negative for copepods. Our data suggest that tadpoles of S. perpusillus are, in general, non-selective omnivores feeding on items in a similar proportion to their occurrence in the environment, while tadpoles of S. littoreus are more selective-feeders, avoiding animal items.

Muitas espécies de anuros que se reproduzem em bromélias apresentam cuidado parental com fêmeas depositando ovos não fertilizados para alimentar os girinos no fitotelma. Os hilídeos do gênero Scinax não apresentam este comportamento, mesmo apresentando girinos exotróficos. O objetivo do presente estudo foi descrever quali-quantitativamente a dieta dos girinos das espécies S. littoreus e S. perpusillus que se desenvolvem no fitotelma da Alcantarea glaziouana (Bromeliaceae). Avaliamos se há diferenças sazonais e espaciais (entre girinos que residem no vaso central e nos vasos laterais da bromélia) na dieta, além de testar a existência de seleção de itens alimentares pelas espécies de anuros. Os itens mais abundantes na dieta de ambos os girinos foram respectivamente: algas, fungos e protozoários. Detrito e restos vegetais estavam presentes em mais de 90% dos estômagos de ambas as espécies. A amplitude de nicho trófico para S. littoreus foi 1,26 enquanto para S. perpusillus foi 1,54. As dietas foram sazonalmente conservativas para ambas as espécies e espacialmente similar apenas para S. perpusillus. Os girinos de Scinax littoreus apresentaram diferenças na dieta de acordo com o microhabitat em que se desenvolviam na bromélia além de apresentar eletividade positiva para fungos e negativa para copépodos. Nossos dados sugerem que S. perpusillus é, em geral, um onívoro não seletivo, alimentando-se de itens em proporção similar da que estes ocorrem no fitotelma, enquanto os girinos de S. littoreus são mais seletivos evitando itens animais.

Many ecological factors are known to influence anuran growth and development. However, little is known about the influence of the shape of the aquatic environment. We investigated how the size of the air–water interface (surface area), water depth, and partitioning the aquatic space independently affect the growth and development of tadpoles of Xenopus laevis. To do this, we used a series of pyramidal frustra and partitioned aquaria. In our experimental containers, as the surface area decreased the dissolved oxygen concentration decreased and the tadpoles' air-breathing rates increased. As the depth of the water increased, the dissolved oxygen concentration decreased and the tadpoles' air-breathing rates increased. When the aquatic space was vertically partitioned to form a maze with corridors either 2 cm or 4 cm wide, the tadpoles avoided the narrow spaces between the partitions. Neither varying the surface area, nor vertically partitioning the aquatic space, significantly affected the growth or development of the tadpoles. However, the tadpoles raised in the shallower containers grew significantly slower than the tadpoles raised in the deeper containers. Tadpoles raised in shallow water behaved differently than those raised in deeper water. Shallow water appeared to prevent the tadpoles from ascending normally to break the surface tension of the water and properly air-breathe. Instead, the tadpoles in the shallow containers often floated at the surface, rather than in their normal position in the water column. Our study suggests that shallow water, independent of other variables such as water volume or dissolved oxygen concentration, may detrimentally impact air-breathing tadpoles, since shallow water appears to physically impede the animals' ability to air-breathe.

Currently, little is known about the seasonal variation of corticosterone (CORT) levels, either baseline or stress response, within freshwater turtles. We conducted a seasonal CORT study with a species of freshwater turtle, Graptemys flavimaculata (Yellow-blotched Sawback; family Emydidae), that is endemic to the Pascagoula River system of southeastern Mississippi. Graptemys flavimaculata is commonly observed while basking on deadwood snags, with us using basking traps and dip nets as active capture methods. We caught both male (n  =  60) and female (n  =  49) turtles during the months of April–October during 2007 and 2008. Immediately after capture, we collected an initial blood sample, confined the turtle for 35 minutes, and then took a second blood sample. Competitive binding radioimmunoassays were done to determine CORT levels. Time zero CORT levels for both sexes were generally lower than previously reported levels for other turtle species, likely due to the trapping methods used. By time 35 min, CORT levels were significantly elevated relative to initial levels. We did not detect seasonal differences in time zero CORT levels for males or females. However, seasonal differences in time 35 CORT levels for males were detected, with higher levels observed during summer months (July, August) relative to spring (April) and fall (October) months. Seasonal differences were also detected in time 35 CORT levels of females, with lower levels observed during July (nesting season) relative to September. This study provides novel information and insight into the differences in seasonal physiological demands for this species, and aquatic turtle species in general, while also providing probable connections of physiology to seasonal life history events.

Recent reports of declines in terrestrial snake populations in the southeastern U.S. have highlighted the need for life history information for these often cryptic animals. In this study, we used radio-telemetry to describe home range size and habitat use of the Florida Pine Snake (Pituophis melanoleucus mugitus), a large fossorial species associated with the endangered Longleaf Pine (Pinus palustris) ecosystem. Florida Pine Snakes had large home ranges that varied in size among individuals (mean  =  59.2 ± 50.8 ha, minimum convex polygon). There was no significant difference between mean annual home range size of males and females, but home range size differed significantly among seasons and between males and females by season. At the home range scale, Florida Pine Snakes selected natural pine forests and mature slash pine plantations, and they tended to use sites with shrubs and vines and very little bare ground at a local scale. As has been observed in other studies, Florida Pine Snakes were highly fossorial and they frequently sought shelter in Southeastern Pocket Gopher (Geomys pinetus) burrows. Snakes in our study rarely crossed paved or graded dirt roads; however, they frequently crossed low-use harrowed dirt roads. Collectively, our findings indicate that Florida Pine Snakes require large contiguous pine forests and that paved and graded roads may be significant barriers to their movement.

We examined the life history of Blackbanded Darters (Percina nigrofasciata) from two streams in the Choctawhatchee River drainage, Florida, over a three-year study period. Blackbanded Darters from Turkey Creek were longer than fish from Ten Mile Creek; however, size-adjusted clutch and egg sizes were similar between populations. Larger females produced larger clutches, whereas egg size did not vary with female body size. Seasonally, clutch sizes were greater in May than in August. When contrasted with previous studies of Blackbanded Darters in Alabama and Louisiana, the reproductive season of Blackbanded Darters in Florida was unusually long, ceasing for only a few months in late fall. The reproductive season was longer in Turkey Creek than in Ten Mile Creek. Differences in thermal regime among streams may explain differences in life history traits among local and distant populations of Blackbanded Darters. This research, alone and in combination with previous studies of this species, emphasizes two main points. First, it reaffirms that life history studies based on a single locality or conducted at a single point in time may fail to capture the full range of variation in life history traits. Second, it highlights the extensive phenotypic variation found in species with broad geographic ranges. Such species lend themselves to comparative and experimental research on patterns and causes of life history variation.

In this study we describe for the first time aspects of the reproductive ecology and behavior of a population of Hyalinobatrachium aureoguttatum located in the Colombian Pacific lowlands. Males vocalize and attend clutches from the underside of leaves overhanging the streams. Males showed high fidelity to their territory; each male repeatedly uses the same leaf for perching, calling, mating, and clutch attendance. There were no significant differences in the environmental variables registered for the microhabitats where males were located with or without clutches, with one or multiple clutches, or between successful or unsuccessful clutches, which suggest that the analyzed variables are not important for the obtention of the clutches and their success. Males were found grouped in the study area at distances varying between 0.3–0.5 m; thus, more than one male can be observed occupying other leaves in the same plant. Fights or aggressive behaviors were not observed in intrusion events by co-specific males in the territory of the resident males; however, we registered a series of movements that resulted in moving the intruder further away. Females almost immediately abandoned the clutches after oviposition, whereas most of the time, at day and night, males stayed near, touching or sitting on one to five egg clutches during most of their embryonic development. This brooding behavior also included hydration, cleaning, and defense of the eggs. Arthropod predation was observed in both attended and abandoned egg clutches; however, in one observation, the behavior of the male moved the predator away and saved the clutch. These observations and the finding of abandoned clutches that did not complete their development suggest that male parental care increases embryo survival and, as a result, his reproductive success.

Moving from one location to another provides animals with obvious benefits, but also incurs costs. When and how far an animal chooses to move is thus of fundamental importance to all aspects of its biology. We investigated movement patterns in a population of Namaqua Dwarf Adders (Bitis schneideri) in southern Africa through the use of radio telemetry. We measured how many individuals moved at different times of the day, at different times of the year, and differences in displacement frequency between sexes. We also assessed the influence of environmental variables (air temperature, relative humidity, atmospheric pressure, and wind speed) on activity levels. Snakes moved almost exclusively during the day-light hours, despite our expectations from the literature. Namaqua Dwarf Adders show limited seasonal variation in activity levels, with males moving more frequently during spring months than in other seasons. Our analysis indicated that movement was linked most closely to environmental conditions during the winter season, when conditions were generally less suitable for movement. We hypothesize that the observed variation in movement patterns at all temporal scales is the result of the selective pressure imposed by the costs of activity during sub-optimal environmental conditions.

The nest environment, in particular sand temperature, is critical to the breeding ecology of sea turtles which lack parental care during their early stages of life. We investigated the effects of sand temperature on emergence success and sex ratio of Olive Ridley (Lepidochelys olivacea) hatchlings in in situ and relocated nests in Alas Purwo National Park (APNP), East Java, Indonesia. Over two years of observation no in situ nests survived due to predation, while emergence success in relocated nests varied between the years. Temperatures above 34°C experienced by the nests over at least three consecutive days during incubation (T3dm) had decreased emergence success in both years. These high temperatures occurred as a result of metabolic heating of developing embryos combined with high sand temperatures. The indirect method of determining sex ratios from nest temperature profiles indicated that the hatchery at APNP generated more male hatchlings than female. Our study provides justification for on-going egg relocation to the hatchery as a conservation management strategy. Therefore the nest environment inside the hatchery needs to be carefully managed so that temperatures do not exceed the viable limit nor unnaturally skew the sex ratio of embryos.

Coloration is a trait frequently cited as important to ecological, and thus evolutionary, processes in amphibians. To fully understand the impact of coloration, a consistent method of color measurement is required, which is often achieved by collecting color information in a captive, laboratory setting. However, results from the lab can only be generalized to the field if coloration remains consistent between the two. In this study we collected spectral data from two discrete color morphs of Plethodon cinereus (erythristic and striped) at two distinct time periods while in captivity to determine whether and how their coloration changed over time. We found that brightness in both color morphs decreased similarly through time, though the change was most pronounced in the erythristic morph. Additionally, we examined the overall coloration change over time using multivariate change vectors and found that the magnitude (amount) of multivariate color change was significantly greater in the erythristic morph as compared to the striped morph (for cheek color patches). Intriguingly, the direction of color change in color space was oriented similarly among measured regions within each morph, whereas the direction of color change differed between morphs, indicating that while coloration changed for all individuals, how that change occurred was morph-specific. We propose a physiological mechanism that may be responsible for the observed changes, and suggest several additional mechanisms that may influence labile coloration in these salamanders. Additionally, our findings suggest that quantifying color from individuals held in captivity should be used with caution, as color changes observed in a laboratory setting may not reflect what is seen in the field.

Vernal pools are preferred breeding habitats for numerous amphibian species. The analysis of prey composition during the amphibian larval stages is necessary to understand diet composition and food choice in aquatic communities. We studied the diet of larvae of Pleurodeles waltl when exogenous feeding begins and throughout the flooding period in an episodic Mediterranean pond. The stomach contents were analyzed and the diet was compared to the availability of prey in the pond. The diet analysis revealed an ample diversity of prey, the most abundant being cyclopoid and calanoid copepods and podocopid ostracods. Changes in the composition of the diet corresponded principally to the variations in the availability of different prey as a consequence of the succession of the zooplankton community throughout the flooding period. However, certain taxa such as large anostracans, small anomopods, and turbellarias were not consumed although they were available and abundant. In contrast, prey scarcely represented in the pond such as coleopteran, dipteran, and hemipteran larvae were efficiently captured, suggesting their accessibility to newt larvae. The proportion of prey found in stomachs with respect to their abundance in the pond increased with larval size, coinciding with a reduction in number and bio-volume of available prey. The results suggest that newt larvae are opportunistic feeders and that breeding success of newts may be highly dependent on early egg-laying to match the abundant food supply found at early flooding stages of vernal pools.