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Anolis lizards are the focus of most Caribbean lizard community ecology studies with few studies including other common species that might influence community structure. To study niche relationships and interspecific interactions in Antiguan lizard communities, we used five offshore islands with varying combinations of three diurnal lizards: Ameiva griswoldi, Anolis leachii, and Anolis wattsi. We collected data on perch height, substrate, thermal microhabitat, body size, head length, daily activity, and abundance to characterize the ecological niche of each species. Ameiva griswoldi was more similar to A. leachii in size and daily activity, but more similar to A. wattsi in perch height, and A. leachii and A. wattsi were more similar in thermal microhabitat. This pattern of niche differentiation was consistent with niche complementarity, where species are similar on some niche axes but differ on others. Using the same niche characteristics as in species comparisons, we tested for a niche shift among islands for A. wattsi. In the absence of A. griswoldi, A. wattsi used lower perches, sunnier microhabitats, and was found more often on the ground. In contrast, with A. leachii absent, A. wattsi perched higher, more often in the shade, and on trunks. Furthermore, A. wattsi was most abundant when with A. leachii only, but least abundant when alone with A. griswoldi. These results suggest interspecific interactions, most likely due to competition and intraguild predation, are important for structuring Antiguan lizard communities.
Trichomycterus crassicaudatus is described as a new species from the Rio Iguaçu basin in southern Brazil. The new species has an exceptionally deep posterior region of the body (caudal peduncle depth 22.8–25.4% SL), resulting in an overall shape which distinguishes it at once from all other members of the Trichomycteridae. The caudal fin of the species is broad-based and forked, a shape also distinguishing it from all other species in the family. A number of autapomorphic modifications of T. crassicaudatus are associated with the deepening of the caudal region, including an elongation of the hemal and neural spines of the vertebrae at the middle of the caudal peduncle. Phylogenetic relationships of the new species are yet unresolved, but it shares a similar color pattern and a thickening of caudal-fin procurrent rays with T. stawiarski, a poorly-known species also from the Rio Iguaçu basin. Coloration and body shape also include similarities with T. lewi from Venezuela.
Two spermatogenetic cycles, vernal and aestival, have been described in temperate colubrid snakes. In both cycles, mating occurs in the spring, although vernal species produce spermatozoa in spring, just before mating, while aestival species use spermatozoa produced the previous summer. In this study, we describe the reproductive cycles of male and female Malpolon monspessulanus (Colubridae), and compare them to previously published cycles of five other snake species, four vernal and one aestival, inhabiting the same area. We also examine the consequences of both spermatogenesis cycles over the entire reproductive processes of male and female snakes in the south-eastern Iberian Peninsula. Vernal species mate later than do aestival species, as males must produce spermatozoa just prior to mating. However, vernal species are able to condense spermatogenesis and vitellogenesis processes, hence undertaking oviposition at the same time as aestival species. Here we discuss advantages of accomplishing the entire reproductive cycle in one (vernal species) or two (aestival species) calendar years. We also found that mature male M. monspessulanus exhibit decreased testes volume relative to body size. Large testes are expected in scenarios of sperm competition. The mating system of M. monspessulanus (territoriality, mate guarding, male–male combat) does not suggest sperm competition, hence it may be more advantageous for males of this species to invest in body size than in testes size.
Playa wetlands are the major habitat for amphibians in the Southern Great Plains, USA. Agricultural cultivation causes playa sedimentation and related hydroperiod reduction in this intensively-farmed region, which in turn affects amphibian community structure. The goals of our study were (1) to investigate the influence of landuse on larval salamander (Ambystoma tigrinum mavortium) occurrence and densities in playas and whether hydroperiod length is an environmental influence on that occurrence, (2) to examine the polymorphic structure (cannibal, intermediate, and typical morphotypes) of larval salamanders and whether the frequency of occurrence of intermediate and typical morphs is associated with the presence of cannibal morphs and variations in hydroperiod length and conspecific density, and (3) to investigate morphological and life history trait differences among morphotypes (i.e., larval periods, growth rates, and body sizes). Cultivation of watersheds negatively affected presence and density of larval salamanders in playas, and this effect was associated with reduced hydroperiods. Although cannibal morphs were rare in playas, their presence negatively influenced presence of intermediate morphs and, thus, in this situation the majority of larvae were typical morphs. When cannibal morphs were absent, intermediate and typical morphs developed in similar proportions among playas with a tendency for intermediate morphs to predominate. Larval density and hydroperiod length were positively associated with the presence of cannibal morphs. Intermediate morphs had distinct growth patterns compared to cannibal and typical morphs and had body size measures (snout-to-vent length and stomach size) in between the two extreme morphs. Cannibal morphs grew faster and reached larger body size at metamorphosis than non-cannibal morphs. When cannibal morphs were absent, intermediate and typical larvae reached larger sizes than when cannibal morphs were present. We conclude that cultivation surrounding playas can negatively influence Ambystoma occurrence in general and especially the cannibal morphotype by reducing wetland hydroperiod. Moreover, a polymorphic community structure in larval amphibians may be important to a properly functioning playa food web.
Synodontis macropunctata, a new species of mochokid catfish, is described from tributaries of the Kasai River in northern Angola. Specimens of this species have been identified as S. zambesensis and more recently as S. nigromaculata. Synodontis macropunctata is distinguished from these species and all Congo basin congeners by the following combination of characters: large, discrete, widely spaced dark spots on the skin; minute, villous papillae on the skin; 27–35 mandibular teeth; 9–10 branched pectoral-fin elements; the lack of a distinct membrane on the maxillary barbel; interrupted premaxillary toothpad; 8–11 branches on the lateral mandibular barbel; and comparatively longer maxillary (138.2–176.3% HL), lateral mandibular (87.2–107.9% HL), and medial mandibular (38.5–54.5% HL) barbels. The description of this species restricts the known distribution of Synodontis nigromaculata within the Congo basin to the Lake Mweru–Luapula River–Lake Banguelu system and to neighboring rivers in the Katanga Province of the Democratic Republic of Congo.
The following is a study of the trophic niche of Phrynops rufipes revealed by an investigation of stomach flushing and fecal samplings. We successfully stomach flushed all 31 adult turtles captured and collected feces from ten of the flushed turtles. Our results show that only an integrated approach using both techniques is able to provide a comprehensive picture of P. rufipes diet. Trichoptera larvae were the most eaten item in numeric terms and in frequency of occurrence, but shrimp contributed the greatest volume of invertebrates. The seeds of most kinds of palm trees common around streams in the area were eaten. Due to the limitations of stomach-flushing technique, palm fruits were underestimated, but they still contributed the highest volume of material flushed from the stomachs and found in the feces. Our findings alter the conclusions concerning the food habits of P. rufipes: it is an omnivore species that feeds in an opportunistic way on a greater quantity of benthonic macro-invertebrates and fishes than was evident from previous studies based on fecal sampling alone.
The use of terrestrial habitat by freshwater turtles is receiving increased attention by herpetologists, driven in part by conservation efforts to protect critical upland habitat. I report on a high degree of non-nesting terrestrial activity by Chrysemys picta in Virginia. During a three-year project, 60 individual adult turtles were followed by radiotelemetry, primarily during the summer, with 22 of them being detected on land. Fifteen turtles dispersed overland at distances up to 3300 m, two turtles nested, four turtles aestivated on land for a mean of 34 days, and an adult male overwintered on land for approximately 290 days. Terrestrial activity was evidently prompted by drying of the home ponds. Most available upland habitats were used, with slight preferences by dispersing turtles for wooded habitats and by aestivating turtles for non-wooded habitats. Aestivation on land by C. picta has rarely been reported but may be fairly common during periods of drought. Overwintering on land by adult C. picta has not been reported and will require additional research to explain the physiological responses needed to survive. This study underscores the importance of upland habitat in the life history and conservation of freshwater turtles.
Fish ecologists often use species-discharge relationships (SDRs) to understand how species richness varies with aquatic habitat availability, but few SDR studies have considered whether the reported SDRs are scale-dependent, or attributed the SDR to a specific causal mechanism. Here, we assessed whether the SDR is scale-dependent by using individual river reaches, rather than complete river basins, as sampling units in a SDR analysis. We also determined whether the SDR is a function of among-reach habitat diversity. To do so, we first tested for longitudinal zonation along three major Pacific Northwest (U.S.A.) rivers. Our zonation tests consistently detected ‘lower,’ ‘middle,’ and ‘upper’ river fish assemblages, each of which was characterized by common patterns in adult habitat use, feeding guild structure, and reproductive behavior, and was associated with predictable habitat conditions. When these longitudinal zones were used as sampling units in a SDR analysis (i.e., total discharge and species richness within each zone), we detected strong linear relationships between discharge and species richness (log10 data). Because individual zones predicted species richness more effectively than complete basins, we conclude that the SDR is scale-dependent. And we infer that among-zone habitat shifts are an important determinant of the SDR, as the slope of the SDR is a function of the differential richness found in each zone.
Trophic niche studies are essential for evaluating ecological interactions between and within species and their evolutionary implications. For example, fundamental aspects of a wide range of hypotheses concerning population divergence, evolution of sexual dimorphism, and adaptations to fluctuating environments rely on dietary evidence. The accuracy of different methodologies used to estimate trophic specializations is therefore a fundamental issue. Under the assumption that direct observations of gastric contents provide accurate information about dietary preferences, I examined how reliably diet is reflected in fecal pellets. I conducted two main comparative tests on living lizards. First, I fed individuals of 23 species with hard- and soft-bodied organisms, and compared fecal pellets. Second, I examined prey items from natural diets represented in feces and gastric contents (stomach-flushing) in a wild population of the lizard Liolaemus tenuis. My results reveal that fecal samples provide inaccurate estimates of lizard trophic preferences, mainly because soft-bodied organisms are destroyed by digestive processes. Even though soft-bodied prey may be essential dietary items (as inferred from gastric analysis), these organisms may be almost entirely absent from feces. I suggest that direct gastric analyses should be the preferred method for analyzing reptilian diets.
Characidium nupelia, new species, is described from the upper Rio Paraguay basin, and C. xavante, new species, from the upper Rio Xingu basin, State of Mato Grosso, Brazil. The two species comprise a group diagnosed by a high number (12–18) of dark vertical bars on the body, each bar having the width of a scale. Characidium nupelia differs from C. xavante by having 12 instead of 10 scales around the caudal peduncle, a narrower interorbital distance, and a deeper caudal peduncle. Both species lack an adipose fin, have an incomplete lateral line, and have a conspicuous dark blotch on the caudal peduncle. Breeding males of the two new species present sexual hooks on some pelvic and pectoral branched fin rays.
Characidium nupelia, nova espécie, é descrita da bacia do alto rio Paraguai, e C. xavante, nova espécie, da bacia do alto rio Xingu, Estado do Mato Grosso, Brasil. As duas espécies formam um grupo diagnosticado pelo elevado número (12–18) de barras verticais escuras no corpo, cada barra com a largura de uma escama. Characidium nupelia difere de C. xavante por apresentar 12 ao invés de 10 escamas circumpedunculares, distância interorbital menor e pedúnculo caudal mais alto. Ambas têm nadadeira adiposa ausente, linha lateral incompleta e uma mancha escura conspícua no pedúnculo caudal. Machos maduros das duas espécies novas apresentam ganchos sexuais em alguns raios ramificados das nadadeiras pélvica e peitoral.
The species of Rineloricaria from the Laguna dos Patos drainage are reviewed. Four species are rediagnosed: R. strigilata, R. cadeae, R. microlepidogaster, and R. longicauda, and two new species are described: R. malabarbai and R. baliola. Rineloricaria malabarbai is distinguished from all other Rineloricaria species except R. maquinensis by its unique abdominal pattern, composed of a large naked area with a single preanal complex of plates and one or two small squarish platelets at the base of pelvic-fin spine and connecting the preanal complex to the lateral abdominal plates, and from R. maquinensis it is distinguished by a longer predorsal length, shorter postanal length, longer abdominal length, broader cleithral width, broader body width at anal-fin origin, deeper head, and shorter maxillary barbel. Rineloricaria baliola is distinguished by its unique color pattern composed of dark, wide bands covering most of the distal one-half of all fins, and by its snout with a roundish naked area, generally reaching to anteriormost pore of infraorbital ramus of sensory canal. The species in Rineloricaria are divided in two phenetic groups, based on general background color pattern, distribution of plates on abdomen, head and snout shape, shape of the naked area at tip of snout, number of lateral body series of plates, and presence of the dorsal-fin spinelet. Species illustrations and a taxonomic key for the Laguna dos Patos drainage are provided.
Son revisadas las especies de Rineloricaria del sistema de la Laguna dos Patos. Cuatro especies son rediagnosticadas: R. strigilata, R. cadeae, R. microlepidogaster, y R. longicauda; y dos nuevas especies se describen para el sistema: R. malabarbai y R. baliola. Rineloricaria malabarbai se distingue de las otras especies de Rineloricaria, excepto R. maquinensis, por su único patrón de placas abdominales compuesto por un gran área desnuda con un complejo de placas preanales y una o dos pequeñas placas cuadrangulares en la base de la espina de la aleta pélvica, que conectan el complejo preanal a las placas abdominales laterales. De R. maquinensis se distingue por presentar mayor longitud predorsal, menor longitud postanal, mayor longitud abdominal, mayor ancho cleithral, mayor ancho del cuerpo en el origen de la aleta anal, cabeza más baja y barbillas maxilares más cortas. Rineloricaria baliola se distingue por su único patrón de coloración, compuesta de oscuras y amplias barras en todas las aletas, comprendiendo la mitad distal, y por su patrón de placas abdominales. Las especies de Rineloricaria son divididas en dos grupos fenéticos, basados en el patrón de coloración general, cobertura de placas en el abdomen, forma de la cabeza y el hocico, forma del área desnuda del extremo del hocico, número de series de placas laterales del cuerpo y presencia de “spinelet” en la aleta dorsal. Se provee una clave taxonómica e ilustraciones para las especies del sistema de la Laguna dos Patos.
Roads have numerous negative ecological effects on terrestrial fauna, and vehicular mortality can have significant demographic consequences for some species. We studied road mortality of reptiles around Carlyle Lake, Clinton County, Illinois, USA, from April 2000 through November 2002, to assess the impact of vehicular traffic and identify influential factors. Carlyle Lake, a popular tourism/recreation area, is situated in a larger agricultural landscape and is home to the largest Illinois population of the endangered Eastern Massasauga (Sistrurus catenatus). We documented 321 cases of reptile road mortality (84 individuals of six turtle species and 237 individuals of nine snake species) while driving our approx. 46 km study route roundtrip daily. Turtle road mortality was highest in May and June, and positively associated with precipitation and minimum daily temperature. Colubrid snake road mortality was highest in April and October, and positively associated with minimum daily temperature. We recorded 42 cases of road mortality of S. catenatus with the highest number occurring from mid-August to mid-September. Road mortality in S. catenatus was biased toward adult males, which show an increase in movement in August, coinciding with the peak of the mating season and a period of high tourist visitation. The traffic intensity on a road segment did not significantly affect the level of road mortality, but segments through high quality habitats had higher levels of mortality than segments through lower quality habitats. Based on our study on the ecology of S. catenatus, we make recommendations to reduce road mortality that should aid in the conservation of the Carlyle Lake population.
Campostoma are ubiquitous across North America, yet relationships among members of the genus are poorly understood. Here we present phylogenetic hypotheses based on analyses of DNA sequence data from the mitochondrial cytochrome b gene. All analyses consistently recovered nine clades of comparable topological structure. Differentiation of the recovered clades did not follow currently accepted taxonomic boundaries, and was not consistent with previously hypothesized relationships among recognized species and subspecies. Rather, the recovered clades corresponded to broad geographic divides and to areas known either to have high rates of endemism or to represent discrete biogeographic provinces, indicating that clades not corresponding to recognized taxa represent additional diversity within the group. This result provides evidence of morphological similarity among genealogically divergent lineages, and supports several disputed descriptions of putative Campostoma taxa based on subtle variation in morphology. At least nine lineages could be recognized as distinct taxa to provisionally resolve differences among prior systematic accounts of Campostoma evolutionary diversity.
The Western Lyresnake (Trimorphodon biscutatus) inhabits arid regions from the desert southwestern United States southward along the Pacific lowland versant to northwestern Costa Rica and exhibits substantial geographic variation in size, squamation, and color pattern across its range. We examined patterns of geographic variation within T. biscutatus using multivariate statistical analyses of 33 morphological characters scored from 429 specimens. Principal components and discriminant analysis revealed six morphologically distinct groups that are generally concordant with lineages recovered in a phylogeographic analysis of mitochondrial DNA and with taxa traditionally recognized as species or subspecies. We conclude that Trimorphodon biscutatus (sensu lato) comprises six evolutionary species (including the recently elevated T. vilkinsonii) and recommend elevating T. biscutatus (sensu stricto), T. lambda, T. lyrophanes, T. paucimaculatus, and T. quadruplex to the species level. A key to the species of Trimorphodon is provided.
There are very few comprehensive studies of the ecology of small-bodied snakes. Here, we describe the ecology and demography of the Southeastern Crowned Snake (Tantilla coronata) based on 1,640 captures on the Savannah River Site in the Upper Coastal Plain of South Carolina, USA from 1951–2007. Female T. coronata were significantly longer, heavier, and heavier-bodied than males but had relatively shorter tails. Clutch size based on oviductal eggs was positively correlated to maternal body mass and length. Snakes exhibited a unimodal seasonal activity pattern that peaked in summer. Pitfall captures were significantly male-biased from July–October, corresponding to the suggested mating period for this species in this part of its range. We identified three classes of animals in the population: neonates, second year animals, and older animals that included both non-reproductive subadults and reproductive adults. Longevity was at least five years for two recaptured males originally captured as mature adults. Centipede species were the exclusive prey identified from T. coronata collected on the Savannah River Site. Our study demonstrates that research on underrepresented species is possible and can contribute to understanding of snake ecology.
Gogo atratus is a new species of anchariid catfish described from the Mananara du Nord River drainage in northeastern Madagascar. It can be distinguished from congeners by a longer snout (54.8–56.4% HL, vs. 47.1–54.3 in congeners) and faintly mottled dark gray coloration (vs. uniform brown, highly mottled dark gray and cream, or mottled brownish-gray). The following combination of characters further distinguishes Gogo atratus from congeners: dorsal-spine length 17.7–20.6% SL, pectoral-spine length 16.5–18.9% SL, length of adipose-fin base 23.6–27.8% SL, head width 17.8–18.9% SL, interorbital distance 28.9–30.5% HL, eye diameter 13.0–14.3% HL, unicuspid teeth, and straight dorsoposterior margin of dorsal fin.
Ecologists often rely on a suite of demographic parameters—such as age structure, body size distributions, population density, and sex ratios—to understand life history patterns, population dynamics, and community structure of snakes. Unfortunately, in many cases little consideration is given to how sampling techniques may influence the outcome of demographic studies. Herein, we use a combination of field capture techniques, an extensive database of field-captured snakes, and laboratory and field experiments to evaluate how capture methods may influence demographic assessments of several North American semi-aquatic snake species, including Agkistrodon piscivorus, Farancia abacura, Nerodia fasciata, N. floridana, N. rhombifer, N. taxispilota, Regina rigida, Seminatrix pygaea, and Thamnophis sauritus. We found that commercially available aquatic funnel traps (i.e., minnow traps) generally yielded biased assessments of population demography, but that the nature and magnitude of these biases varied predictably by species and trap type. Experimental manipulations of funnel opening diameter in aquatic funnel traps demonstrated that such modifications allowed for capture of larger snakes but that the size of funnel opening necessary to capture the largest individuals varied between species. Additionally, we found differences between snake species in their ability to escape from different types of traps at birth, suggesting that escape of neonates through trap mesh can lead to the lack of small snakes often observed in field samples. Overall, our results demonstrate that capture methods may bias assessments of snake population demography, but that careful design of sampling methodology, with consideration of potential biases, can yield meaningful data on snake biology.
Astyanax armandoiLozano-Vilano and Contreras-Balderas, 1990, a characid described as endemic to a small stream in southern Mexico, is hereby synonymized with A. aeneus (Günther, 1860), a species widespread in northern Central America. Astyanax armandoi was diagnosed by its expanded lower lip, in combination with a suite of osteological characters. The labial expansion has been shown in other Astyanax populations (in Campeche and Chiapas, Mexico) to be an ecophenotype, an adaptation to hypoxia. The osteological, meristic, and morphometric characters of A. armandoi are compatible with the remarkable intra- and interpopulational variation of A. aeneus. The type locality has been repeatedly visited in the last decade; no further specimens identifiable as A. armandoi have been found, only typical A. aeneus. This conclusion implies that A. armandoi should be taken off the Mexican list of endangered species (NOM-059-SEMARNAT-2001) and similar lists.
Astyanax armandoiLozano-Vilano and Contreras-Balderas, 1990, un carácido descrito como endémico de un pequeño arroyo en el sur de México, se considera en este trabajo como sinónimo de A. aeneus (Günther, 1860), especie de amplia distribución en el norte de Centroamérica. La diagnosis de A. armandoi se basa en su labio inferior expandido, junto con un conjunto de caracteres osteológicos. La expansión labial se ha observado también en otras poblaciones de Astyanax (en Campeche y en Chiapas, México) y se trata de un ecofenotipo, una adaptación a condiciones de hipoxia. Los caracteres osteológicos, merísticos, y morfométricos de A. armandoi son compatibles con la notable variación intra- e interpoblacional de A. aeneus. La localidad tipo ha sido visitada repetidamente durante la última década sin que se hayan encontrado más especímenes identificables como A. armandoi, sólo el típico A. aeneus. Esta conclusión implica que A. armandoi debe borrarse de la Norma Oficial Mexicana (NOM-059-SEMARNAT-2001) y de listas similares de especies en peligro.
Desert Tortoises (Gopherus agassizii) in the Sonoran Desert typically occur on rocky slopes and bajadas and are absent from intermountain valley floors. Tortoises also occur along deeply incised washes emanating from rocky bajadas, using caliche caves as shelter sites. The Florence Military Reservation (FMR), in south-central Arizona, is typified by gently sloping alluvial fans bisected by steeply incised washes. One 10.9-ha hill consisting of volcanic outcrops and boulders occurs at the northern end of the reservation. Tortoise locations at FMR were concentrated around incised washes with dense caliche caves or near the volcanic hill. Home ranges of male and female tortoises were not significantly different, and the sexes used shelter types similarly. Tortoises used caliche caves as shelter more than other shelter types, especially those tortoises without access to the rocky hill. Compositional analysis of the three principal habitat types used by tortoises at FMR revealed that they selected incised washes over the other habitat types. However, we did not find tortoises in washes with few caliche caves. These results suggest that availability of shelter sites strongly influences tortoise distribution at FMR.
The broad and imprecise type localities of Crotalinus catenatusRafinesque, 1818 (now Sistrurus catenatus) and Crotalinus viridisRafinesque, 1818 (now Crotalus viridis) are re-identified based on a published account of the collector's travels as well as an examination of the relationship and contacts between the collector and the author of the type description. Both type specimens are lost. Unfortunately, enhanced resolution of the type locality of S. catenatus places it within the range of S. c. tergeminus Say, 1823 (a subsequently described subspecies). Thus, the name S. c. catenatus incontrovertibly applies to the form currently recognized as S. c. tergeminus, which in turn renders the latter as a subjective junior synonym of the former, leaving the eastern form with an unfamiliar name (Crotalus messasaugusKirtland, 1838). To conserve prevailing usage, we are preparing an appeal to the International Commission of Zoological Nomenclature (ICZN) to allow a neotype of Sistrurus catenatus to be designated from the type locality of Crotalus massassaugus. In the interim, existing use of the names should be continued.
Between 1995 and 1998 we studied the effects of water level, moon phase, and site on the number of caimans observed in spotlight surveys in the Mamirauá Sustainable Development Reserve, Brazilian Amazonia. Multiple linear regression analyses including water level of the Amazon River and the moon phase explained 91 and 73% of the variance in number of Melanosuchus niger seen in spotlight surveys in Lago Mamirauá and Cano Mamirauá, respectively, and 60 and 76%, respectively, of the variance in the number of Caiman crocodilus seen. Water level had a statistically significant and negative effect on the number of M. niger and C. crocodilus seen. Moon phase had no significant effect on the number of C. crocodilus seen, but more M. niger were detected in Lago Mamirauá on nights with more moon light. The regression equations derived for Lago Mamirauá and Cano Mamirauá did not adequately predict the variation in numbers seen in 18 other water bodies in the Mamirauá Reserve. Analysis of covariance showed an interaction between water level and site on the numbers of M. niger and C. crocodilus observed in the spotlight surveys in these water bodies, indicating that the effect of water level depends on the site. In these analyses, moon phase did not have a significant effect on either species, and there was no interaction between moon phase and site. To monitor natural tendencies, or impacts (e.g., controlled commercial hunting), on caiman populations of Mamirauá Reserve, it will be necessary to undertake regular spotlight surveys in many water bodies of all types at a narrow range of water level to have confidence in the results.
We recorded the pattern morph for 9,950 frogs captured at nine locations in northeastern Puerto Rico over a 25-year period from 1978–2002. Data revealed 21 distinct pattern morphs including a variety of stripes, bars, and spots. Analysis of morph frequencies among plots showed significant differences, with longitudinal stripes more common in grassland and disturbed areas, and spot and bar morphs more common in forests where palm and bromeliad axils are important habitat features. Comparison of morph frequencies through time at the same sites showed temporal shifts immediately following Hurricane Hugo in 1989. We suggest that the pattern polymorphism is maintained in part by local habitat matching resulting from selection pressure from visual predators.
The Concho Water Snake (Nerodia harteri paucimaculata) is confined to the Concho–Colorado River valley of central Texas, thereby occupying one of the smallest geographic ranges of any North American snake. In 1986, N. h. paucimaculata was designated as a federally threatened species, in large part because of reservoir projects that were perceived to adversely affect the amount of habitat available to the snake. During a ten-year period (1987–1996), we conducted capture–recapture field studies to assess dynamics of five subpopulations of snakes in both natural (river) and man-made (reservoir) habitats. Because of differential sampling of subpopulations, we present separate results for all five subpopulations combined (including large reservoirs) and three of the five subpopulations (excluding large reservoirs). We used multistate capture–recapture models to deal with stochastic transitions between pre-reproductive and reproductive size classes and to allow for the possibility of different survival and capture probabilities for the two classes. We also estimated both the finite rate of increase (λ) for a deterministic, stage-based, female-only matrix model using the average litter size, and the average rate of adult population change, λ ˆ, which describes changes in numbers of adult snakes, using a direct capture–recapture approach to estimation. Average annual adult survival was about 0.23 and similar for males and females. Average annual survival for subadults was about 0.14. The parameter estimates from the stage-based projection matrix analysis all yielded asymptotic values of λ < 1, suggesting populations that are not viable. However, the direct estimates of average adult λ for the three subpopulations excluding major reservoirs were λ ˆ = 1.26, SE ˆ(λ ˆ) = 0.18 and λ ˆ = 0.99, SE ˆ(λ ˆ) = 0.79, based on two different models. Thus, the direct estimation approach did not provide strong evidence of population declines of the riverine subpopulations, but the estimates are characterized by substantial uncertainty.
On 6 June 2005, the ROV Tiburon of the Monterey Bay Aquarium Research Institute captured approximately 24.4 min of footage (30 frames s−1) of a female ceratioid anglerfish, identified as a member of the genus Oneirodes, off the coast of Monterey, CA, at a depth of 1474 m. To gain insight into ceratioid behavioral ecology, this sequence was digitized and analyzed frame-by-frame. All relevant behaviors were described and the kinematics of one slow-swimming and one directional change sequence were quantified. These sequences captured both reduced (slow-swimming) and prominent (directional change) functions of the pectoral fins in producing motion. The angler was initially sighted passively drifting with its illicium extended. It swam away rapidly when approached by the ROV, but for most of the time, it remained lethargic, drifting with no preferred body orientation. When progressing, however, the fish swam slowly and intermittently at approximately 0.24 body lengths s−1, with its pectoral fins beating in-phase. Overall, the observed behaviors of Oneirodes support the hypothesis that these animals are lethargic, lie-and-wait predators, well adapted to the low energy conditions of deep-sea environments.
Populations of the genus Gekko from three southern islands of the Tokara Group, Ryukyu Archipelago are known to be unique in lacking distinct preanal pores even in adult males. Recently, we found an almost identical morphotype from five islands of the Amami Group, where only G. hokouensis, a species having distinct preanal pores in adult males, has hitherto been recorded. To clarify the taxonomic status of these poreless geckos from the Tokara and Amami Groups, we conducted allozyme and morphological comparisons of Gekko specimens collected from these eight islands and one adjacent island. Results of the allozyme analyses showed the presence of fixed allelic differences at 7–14 loci between samples of the poreless form and sympatric G. hokouensis from each of the Amami islands, confirming their reproductive isolation. Our data further revealed the presence of two genetically divergent groups within the poreless form that are distinct from each other by fixed allelic differences at no less than 30% of loci examined. Ranges of these two groups are contiguous with each other but do not overlap on a single island. Distance analysis showed that one of the two groups is genetically much closer to G. hokouensis than to the other. These results strongly suggest that each of them represents an evolutionarily independent unit and deserves recognition as a full species. We describe these species based on a set of characters that clearly discriminate them from all other congeneric species hitherto described, and we briefly discuss their historical biogeography.
The reproductive behavior and mating system of the Rock Wrasse (Halichoeres semicinctus) was recorded and monitored around Big Fisherman Cove, Santa Catalina Island, CA from April 2001 to September 2002. Four sites with different relative densities were visited daily throughout the summer spawning season and once a month throughout the spring and fall. Group spawning was the dominant mating system among smaller individuals (<200 mm) with 8–12 individuals in the spawning aggregations. Large (>200 mm) terminal phase males held territories which were 4–5 m2 and were observed courting on multiple occasions in an attempt to pair spawn, but only three pair spawns were witnessed during the study. Elaborate courtship displays, including vertical rushes and lateral displays by the males within their territory, preceded pair spawning attempts. Spawning occurred primarily in the morning, but aggressive behavior by the territorial males continued throughout the day. The highest level of both group and pair spawning activity occurred at the highest density site, and only group spawning was seen at other sites. Density transect data showed that ratios of initial phase: terminal phase individuals were skewed toward initial phase in late spring and early fall and were skewed toward terminal phase individuals during peak spawning months (July and August) when many aggregations were present. The overall sex ratio in Rock Wrasse from Santa Catalina Island was nearly 1∶1, and histological data suggest that sex-changed individuals made up 38% of studied males. These data suggest that Rock Wrasse utilize a context-dependent, dualistic mating system that may act to increase opportunities for mating and thus, their overall reproductive output.
A new species of slingjaw wrasse, Epibulus brevis, is described from the tropical West Pacific. It is very similar to the common and wide-ranging E. insidiator, differing in the relatively drab coloration of the male, the presence of prominent black pigment on the pectoral fins of most females, smaller size, slightly longer pectoral fins, and genetically as determined by mitochondrial DNA analysis. It lives in more protected inshore waters than E. insidiator.
Embryos of beach-spawning California Grunion incubate terrestrially buried in sand above the tide line. Out of water, these marine teleosts may encounter osmotic challenges including dilution by rainfall or freshwater runoff, or hypersalinity from evaporation or human activities. To test the physiological tolerance of California Grunion embryos, we incubated them in sand at different, ecologically relevant salinities, bracketing their physiological tolerance between 16 and 48 ppt. Fertilization percentage, embryo survival, hatching success, and larval length all decreased when salinity was higher or lower than control seawater, 32 ppt. Some embryos developed deformities that prevented hatching when incubated at high salinities. Mortality at each life stage resulted in significantly lower total survival in hyposaline or hypersaline incubation conditions. Effects of altered salinity include significantly reduced fertilization of eggs, greater mortality of zygotes, smaller hatchlings, and significantly decreased ability to hatch, even for apparently viable full-term embryos. California Grunion eggs are vulnerable to lethal and sublethal effects of altered salinity during early development in beach sand. Coastal management should strive to avoid potentially serious negative effects of altered salinity on the California Grunion's beach nursery grounds.
The archival records of the ASIH are administered by the Smithsonian Institution Archives in Washington, D.C. The records occupy 40 cubic feet of space and are maintained under optimal conditions in a remote storage facility in Boyers, PA. This paper describes the transfer of the Society's records to the Smithsonian Institution in 1974, the additional deposits in the following years, and the basic arrangement and importance of the records. The archival collection is available for research, and anyone interested in the history of the Society may access it by prior arrangement with the Smithsonian Institution Archives.
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